r _ru_n-_n_-rv n__n. REESE LIBRARY OF T1IK UNIVERSITY OF CALIFORNIA Works of Prof. Robt H, Thurston. Published by JOHN WILEY & SONS, 53 E. Tenth Street, New York. MATERIALS OP ENGINEERING/. A work designed for Engineers, Students, and Artisans in woo*, metal, and stone. AJso as a TEXT-BOOK in Scientific Schools, show- ing the properties of the subjects treated. By Prof. R. H. Thurston. Well illustrated. In three parts. Part I. THE NON-METALLIC MATERIALS OF ENGINEER- ING AND METALLURGY. With Measures in British and Metric Units, and Metric and Reduction Tables 8vo, cloth, $3 00 Part II. IRON AND STEEL. The Ores of Iron ; Methods of Reduction ; Manufacturing Processes; Chemical and Physical Properties of Iron and Steel ; Strength, Duc- tility, Elasticity and Resistance ; Effects of Time, Temperature, and repeated Strain ; Methods of Test ; Specifications 8vo, cloth, 3 50 Part III. THE ALLOYS AND THEIR CONSTITUENTS. Copper, Tin, Zinc, Lead, Antimony, Bismuth, Nickel, Aluminum, etc.; The Brasses, Bronzes; Copper-Tin-Zinc Alloys; Other Valuable Alloys ; Their Qualities, Peculiar Characteristics ; Uses and Special Adaptations; Thurston's "Maximum Alloys"; Strength of the Alloys as Commonly Made, and as Affected by Special Conditions; The Mechanical Treatment of Metals 8vo, cloth, 2 50 "As intimated above, this work will form one of the most complete as well as modern treatises upon the Materials used in all sorts of Building Constructions. As a whole it forms a very comprehensive and practical hook for Engineers, both Civil and Mechanical." American Machinist. " We regard this as a most useful book for reference in its departments ; it should be hi every Engineer's library." Mechanical Engineer. MATERIALS OP CONSTRUCTION. A Text-book for Technical Schools, condensed from Thurston's " Materials of Engineering." Treating of Iron and Steel, their ores, manufacture, properties and uses ; the useful metals and their alloys, especially brasses and bronzes, and their "kalchoids": strength, ductility, resistance, and elasticity, effects of prolonged and oft- repeated loading, crystallization and granulation ; peculiar metals : Thurston's " maximum alloys " ; stone ; timber ; preservative pro- cesses, etc., etc. By Prof. Robt. H. Thurston, of Cornell University. Many illustrations Thick 8vo, cloth, 500 "Prof. Thurston has rendered a great service to the profession by the publication of this thorough, yet comprehensive, text-book. . . . The book meets a long-felt want, end the well-known reputation of its author is a sufficient guarantee for its accuracy and thoroughness." Building. TREATISE ON FRICTION AND LOST WORK IN MACHIN- ERY AND MILL WORK. Containing an explanation of the Theory of Friction, and an account of the various Lubricants in general use, with a record of various experiments to deduce the laws of Friction and Lubricated Surfaces, etc. By Prof. Robt. H. Thurston. Copiously illustrated.. 8vo, cloth, 300 "It is not too high praise to say that the present treatise is exhaustive and a complete review of the whole subject." American Engineer. STATIONARY STEAM-ENGINES. Especially adapted to Electric Lighting Purposes. Treating of the Development of Steam-engines the principles of Construction and Economy, with description of Moderate Speed and High Speed En- gines. By Prof. R. H. Thurston 12mo, cloth, 150 " This work must prove to be. of great interest to both manufacturers and users of steam-euyiucs." Uuuder and Woodworker , DEVELOPMENT OP THE PHILOSOPHY OP THE STEAM- ENGINE. By Prof. R. H. Thurston 12mo, cloth, $0 75 "This small book of forty-eight pages, prepared with the care and pre- cision one would expect from the scholarly Director of the Sibley College of Engineering, contains all the popular information that the general student would want, and at the same time a succinct account covering so much ground as to be of great value to the specialist." Public Opinion. A MANUAL OF STEAM BOILERS, THEIR DESIGNS, CON- STRUCTION, AND OPERATION. For Technical Schools and Engineers. By Prof. R. H. Thurston. (183 engravings in text.) Second edition 8vo, cloth, 5 00 " We know of no other treatise on this subject that covers the ground so thoroughly as this, and it has the further obvious advantage ol being anew and fresh work, based on the most recent data and cognizant of the latest discoveries and devices in steam boiler construction." Mechanical News. STEAM-BOILER EXPLOSIONS IN THEORY AND IN PRAC- TICE. Containing Causes of Preventives Emergencies Low Water Con- sequences Management Safety Incrustation Experimental In- vestigations, etc., etc., etc. By R. H. Thurston, LL.D., Dr. Eng., Director of Sibley College, Cornell University. With many illus- trations 12mo, cloth, 150 "Prof. Thnrston has had exceptional facilities for investigating the Causes of Boiler Explosions, and throughout this work there will be lound matter of peculiar interest to practical men." American Machinist. " It is a work that might well be in the hands of every one having to do with steam boilers, either in design or use." Engineering News. A HAND BOOK OF ENGINE AND BOILER TRIALS, AND THE USE OF THE INDICATOR AND THE BRAKE. By R. H. Thurston, Director of Sibley College, Cornell University. Second edition revised 5 00 "Taken altogether, this book is one which every Engineer will find of value, containing, as it does, much information in regard to Engine and Boiler Trials which has heretofore been available only in the form of scat- tered papers in the transactions of engineering societies, pamphlet reports, note-books, etc." Railroad Gazette. CONVERSION TABLES. Of the Metric and British, or United States WEIGHTS AND MEAS- URES. With an Introduction by Robt. H. Thurston, A.M., C.E. 8vo, cloth, 1 00 " Mr. Thiirstpn's book is an admirably useful one, and the very difficulty and unfamiliarity of the Metric System renders such a volume as this almost indispensable to Mechanics, Engineers, Students, and in fact all classes of people." Mechanical News. REFLECTIONS ON THE MOTIVE POWER OF HEAT. And on Machines fitted to develop that Power. From the original French of N. L. S. Carnot. By Prof. R. H. Thurston 12mo, cloth, 2 00 From Mons. Haton de la Goupilliere, Director of the Ecole Nationals Superieure des Mines de France, and President of La Societe d" 1 Encourage- ment pour r Industrie Rationale: - "I have received the volume so kindly sent me, which contains the trans- lation of the work of Carnot. You have rendered tribute to the founder of the science of thermodynamics in a manner that will be appreciated by the whole French people." A MANUAL OF THE STEAM ENGINE. A companion to the Manual of Steam Boilers. By Prof. Robt. H. Thurston. 2 vols 8 vo, cloth, 12 00 Part I. HISTORY, STRUCTURE AND THEORY. For Engineers and Technical Schools. (Advanced courses.) Nearly 900 pages Bvo, cloth, 7 50 Part II. DESIGN, CONSTRUCTION AND OPERATION. For Engineers and Technical Schools. (Special courses in Steam Engineering.) 8vo, cloth, 750 Those who desire an edition of this work in French, can obtain it at Baudry et Cie, itue des Saints- Peres, 15, Paris. THE ANIMAL AS A MACHINE AND A PRIME MOTOR, AND THE LAWS OF ENERGETICS. By Prof. R. H. Thurston... 12uio, cloth, 100 OF THE TJNIVERSIT^ OIW41* A TREATISE ON BRASSES, BRONZES, The Publishers and the Author will be grateful to any of the readers of this volume who will kindly call their attention to any errors of omission or of commission that they may find therein. It is intended to make our publications standard works of study and reference, and, to that end, the greatest accuracy is sought. It rarely happens that the early editions of works of any size are free from errors ; but it is the endeavor of the Publishers to see them removed immediately upon being discovered, and it is therefore desired that the Author may be aided in his task of revision, from time to time, by the kindly criticism of his readers. JOHN WILEY & SONS. 53 EAST TENTH STREET. (UNIVERSITY) NEW YORK: JOHN WILEY & SONS, PUBLISHERS, 53 EAST TENTH STREET. 1893 H -8. 1 u I 4 A TREATISE ON BRASSES, BRONZES, AND OTHER ALLOYS, AND THEIR CONSTITUENT METALS. PART III. MATERIALS OF ENGINEERING. BY ROBERT H. THURSTON, LL.D., DR. ENGINEERING, DIRECTOR OF SIBLEY COLLEGE, CORNELL UNIVERSITY j FIRST PRESIDENT AMERICAN SO- CIETY OF MECHANICAL ENGINEERS: MEMBF.R OF AMERICAN SOCIETY CIVIL ENGINEERS; AMERICAN INSTITUTE MINING ENGINEERS; SOCIE'TEDES INGE*NIEURSCIVILS; VEREIN DEUTCHER INGENIEURE; OESTERREICHISCHER^NGENIEI R- UND ARCHITEKTEN VEREIN ; INSTITUTION OF ENGINEERS AND SHIPBUILDERS IN SCOTLAND ; BRITISH INSTITUTION OF NAVAL ARCHITECTS ; FELLOW OF AM. Assoc. FOR ADVANCEMENT OF SCIENCE; NEW YORK ACADEMY OF SCIENCES, ETC., ETC., ETC. SECOND EDITION, NEW YORK : JOHN WILEY & SONS, PUBLISHERS, 53 EAST TENTH STREET. 1893 COPYRIGHT, 1884, BY ROBERT H. THURSTGN. COPYRIGHT, 1889, BY ROBERT H. THURSTON. Press of J. J. Little & Co. Astor Place, New York CONTENTS. CHAPTER I. HISTORY AND PROPERTIES OF THE METALS AND THEIR ALLOYS. ART. PAGH 1. Ancient knowledge of Metals 3 2. Metallurgy, Schedule of Chemical Processes 5 3. Calcination and Roasting 9 4. Smelting 1 1 5. Fluxes *.\N. . 12 6. Fuels 13 7. Mechanical Processes 13 8. Working of Metals H 9. Metal defined 1 6 10. Useful Metals 16 1 1 . Laws of Ore Distribution 17 12. Requirements of the Engineer 17 13. Special Properties of Metals 18 14. Non- Ferrous Metals 19 15. Relative Tenacities 19 16. Hardness .' 20 1 7. Conductivity 21 1 8. Lustre 24 1 9. Densities and Weights 25 20. Ductility and Malleability 27 21. Odor and Taste 28 22. Characteristics in General 30 23. Crystallization 30 24. Specific Heats 31 25. Expansion by Heat 34 26 . Fusibility, Latent Heat 36 27. Chemical Character 39 28. Alloys 39 VI CONTENTS. CHAPTER II. THE NON-FERROUS METALS. ART. PAGE 29. Copper, History and Distribution 42 30. Qualities of Copper 43 3 1 . Ores and Sources 44 32. Processes of Reduction 47 33. Details 47 34. Properties of Copper 54 35. Commercial Copper 55 36. Sheet and Bar Copper 59 37. Tin, Sources and Distribution 64 38. Reduction of Ores 64 39. Commercial Tin 66 40. Zinc, History and Sources 40 4 1 . Ores of Zinc, Smelting 41 42. Metallic Zinc 73 43. Lead 77 41. Ores of Lead 78 45. Smelting Galena 79 46. Commercial Lead 8 1 4 7. Antimony 82 48. Bismuth and its Ores 83 49. Nickel and its Ores 84 50. Uses of Nickel 86 5 1 . Aluminium 88 52. Mercury 90 53. Platinum 92 54. Magnesium , 94 55. Arsenic 95 56. Iridium . . 96 57. Manganese 87 58. Rare Metals 98 59. Commercial Metals, Prices 99 CHAPTER III. PROPERTIES OF ALLOYS. 60. General Characteristics 102 6 1. Chemical Nature of Alloys 104 CONTENTS. Vll LRT. PAGE 62. Specific Gravity .................................... 108 63. Fusibility .......................................... no 64. Liquation ......................................... 113 65. Specific Heat ...................................... 1 16 66. Expansion by Heat ................................. 1 1 6 67. Thermal Conductivity ............................... 1 1 8 68. Electric " ............................... 120 69. Crystallization .............................. . ....... 123 70. Oxidation ......................................... 1 24 71. Mechanical Properties ............... ........ ....... 126 CHAPTER lYjWIVERSITT THE BRONZES. 72. Copper Alloys ; Bronze and Brass defined .............. 130 73. History of Bronze .................................. 131 74. Copper-Tin Alloys ................................. 134 75. Properties ......................................... 136 76. Principal Bronzes ................................... 137 77. Early Bronzes ...................................... 139 78. Oriental Bronzes ................................... 140 79. Density of Bronze .................................. 141 80. Quality of Ordnance Bronze .......................... 141 81. Phosphor-Bronze ................................... 143 82. Uses of Phosphor-Bronze ........................... 145 83. Table of the Bronzes ................................ 149 ' "" CHAPTER V. THE BRASSES. 84. Brass defined ................................. ..... 158 85. Composition of Brass ................................ 158 86. Mallett's Classification ............................... 159 87. Uses of Brass ...................................... 1 59 88. Muntz Metal ....................................... 160 89. Special Properties ................................... 161 90. Application in the Arts ............................... 162 91. Working Brass ...................................... 163 92. Properties or Brass ................................. 165 Vlll CONTENTS. CHAPTER VI. THE KALCHOIDS AND MISCELLANEOUS ALLOYS. ART. PAGE 93. Use of various Alloys 172 94. Copper-Tin-Zinc Alloys 172 95. " Iron and Zinc , . 174 96. " " " Tin 174 97. Manganese-Bronze 175 98. " " Preparation 176 99. Aluminium " 178 100. " " Uses 1 80 101. Copper-Nickel Alloys 181 102. " " and Zinc (German Silver) 182 103. " andiron 183 104. ". Antimony 185 105. " " Bismuth 186 106. " Bismuth ; Bismuth-Bronze 186 107. " " Cadmium 186 1 08. " " Lead 187 109. " " Silicon 187 1 10. " " " ; Silicon-Bronze 188 in. " Tin and Lead 188 112. " " Antimony and Bismuth 188 113. " " Zinc and Iron 189 1 14. " and Mercury ; Dronier's Alloy 189 115. Complex Copper Alloys 189 1 1 6. Bismuth Alloys 1 90 1 1 7. Tin and Lead ; Fusible Alloys 193 1 1 8. Lead and Antimony 193 119- Tin " " 198 120. " " Lead ; Fusible Alloys 198 121. " " Zinc 201 122. Antimony, Bismuth and Lead 202 123. Tin " " 202 124. " " " Zinc 202 125 " Bismuth and Lead 202 1 26. Pewter and Britannia Metal 205 127. Iron and Manganese 202 1 28. Platinum and Iridium 203 129. Spence's " Metal " , 204 CONTENTS. ix CHAPTER VII. MANUFACTURE AND WORKING OF ALLOYS. ART. PAGE 130. Alloy of General Use ; Brass Working 205 131. The Brass Foundry 207 132. Melting and Casting 207 133. Furnace Manipulation 209 134. Preparation of Alloys 210 135. Effect of Small Doses of Metal 212 136. Art Castings in Bronze 212 137. Stereotyping 214 138. German Silver 215 1 39. Babbitt's Anti- friction Metal 515 140. Solders 216 141. Standard Compositions 218 142. Special Recipes 221 143. Classified Lists . . . < 226 144. Bronzing 237 145. Lacquering 239 CHAPTER VIII. STRENGTH AND ELASTICITY OF NON-FERROUS METALS. 146. Strength of Non-Ferrous Metals 242 147. Resistances Classified , 242 148. Factors of Safety " 244 149. Measures of Resistance * 246 1 50. Methods of Resistance 247 151. Equation of Resistance Curves 248 152. The Elastic Limits 249 153. Impact, Shock 251 154. Resilience 252 155. Proportioning for Shock 255 156. Methods of Test 255 157. Compression 255 158. Structure and Composition 256 1 59. Transverse Stress 256 160. Distribution of Resistances 258 1 6 1 . Theory of Rupture 259 X CONTENTS. ART. PAGE 162. Formulas for Transverse Loading ... 260 163. Modulus of Rupture 262 1 64 . Elastic Resistance 263 165. Torsional " 267 1 66. Strength of Shafts 268 167. Tenacity of Copper 270 168. Tests " " 271 169. " " Commercial Copper. 272 1 70. Shearing Resistance " , 277 171. Resistance to Compression 278 1 72. Compression by Impact 281 1 73. Transverse Tests of Copper 284 1 74. Modulus of Elasticity 286 1 75. Copper in Torsion . . 287 176. Mean of Results of Tests of Copper 287 177. Strength of Tin 288 178. Transverse Resistance of Tin 292 179. Modulus of Elasticity of Tin 294 1 80. Tin in Torsion 294 1 8 1. Strength of Zinc 296 182. Tests of Zinc 297 183. Various Metals 298 184. Wertheim on Elasticity 300 185. BischofFs Tests 303 CHAPTER IX. STRENGTH OF BRONZES AND OTHER COPPER-TIN ALLOYS. 1 86. The Bronzes defined 306 187. Tenacity of Gun Bronze; Wade's Experiments 306 1 88. " " " " Anderson 308 189. " " Bell Metal, Mallett 308 190. Ordnance Bronze in Compression 309 191. Hardness of " (Riche) 311 192. Tenacity of Phosphor-Bronze 312 193. Resistance " to Abrasion 316 194. Strength of Manganese- Bronze 316 195. Manganese-Bronze under Impact 317 196. Strength of Ferrous Copper. 319 CONTENTS. XI ART. . PAGE 197. Copper-Tin Alloys, U. S. Board 320 198. Metals used in Research ... 322 199. Alloys tested. '.*> 322 200. Temperatures of Casting ' ^^ , ^^^ . . - 324 201. External appearance of Test Pieces^f^^^^^^x. 325 202. Behavior under Test. ^tXNl.VJCiRsicp-y: . 326 203. Appearance of Fractures v ^^^fFOtHNlA^ x ** 33 204. Records of Test ."TTrTTTT. . . 335 205. Final Results. 341 206. Strain- diagrams of Bronzes in Tensions 344 207. Tenacities of Bronzes. 344 208. Strain-diagrams of Bronzes in Compression 346 209. Transverse Strain-diagrams 348 210. Comparison of Resistances '. 350 211. " Resiliences 353 212. " Specific Gravities 355 213. " " Elastic Limits 358 214. " " Moduli of Elasticity 361 215. " " Ductilities 361 216. " " Conductivities 363 217. " " Hardness, etc ; . . 363 CHAPTER X. STRENGTH OF BRASSES AND OTHER COPPER-ZINC ALLOYS. 218. The Brasses denned : 366 219. Earlier Experiments. . 367 220. Strength of Sterro-metal 368 221. Moduli of Elasticity 368 222. Copper-Zinc Alloys tested for the U. S 369 223. Alloys tested 370 224. Appearance of Test-pieces 371 225. " " Fractures 373 226. Temperatures of Casting - 275 227. Mixtures and Analyses 376 228. Results of Tests 378 229. Conclusions from Tests 379 230. Notes on Tests 383 231. Tenacity of Brasses 384 xii CONTENTS. 232. Resistance to Compression 385 233. " " Transverse Stress 387 234. " " Torsion 391 235. " of Shafts 392 236. Records of Tests 393 237. Strain-diagrams of Tension 404 238. " " " Transverse Tests 406 239. Resistances compared 406 240. Resiliences 409 24 1 . Elastic Limits " 409 242. Moduli 411 243. Specific Gravities compared 412 244. Ductilities 412 245. Summary 413 CHAPTER XI. STRENGTH OF THE KALCHOIDS AND OTHER COPPER-TIN-ZINC ALLOYS. 246. The Kalchoids 4 14 247. Sterro-metal 415 248. Copper-Tin-Zinc Alloys 416 249. Plan of Research 416 250. Selected Alloys 418 251. Details of Investigation 419 252. Method of Registry 425 253. General Deductions 427 254. Strain Diagrams 429 255. Tenacities 430 256. Ductility 434 257. Improvement 437 258. Thurston's " Maximum " Bronzes 440 259. Results of Tests 442 260. Discussion 443 261. Conclusions 446 262. Other Researches 447 CHAPTER XII. THE STRENGTH OF ZINC-TIN AND OTHER ALLOYS. 263. Zinc-Tin Alloys 449 264. Strength and Density 450 CONTENTS. Xlll AT. PAGE 265. Grey Ternary Alloys 450 266. Earlier Investigations 45 1 267. Records of Tests 452 CHAPTER XIII. CONDITIONS AFFECTING STRENGTH. 268. Conditions modifying Tenacity of Non-Ferrous Metals. .. 476 269. Heat " " "Copper 476 270. " " " " Bronze 477 271. " " " " Various Metals 480 272. " " Elasticity 480 273. Stress produced by Change of Temperature 481 274. Effect of Sudden Variation " " 482 275. " " Chill-Casting 483 276. " " Tempering and Annealing; on Density 484 277. " " " on Tenacity 487 278. " " Temperature of Casting 488 279. " " Time of Loading 489 280. " " Prolonged Stress on Tin and Zinc ... 492 281. Effect of Prolonged Stress on Bronze 497 282. Fluctuation of Resistance 498 283. Effects of Intermitted and Steady Stress on Resistance.. 500 284. " " Stress on Deflection 502 285. " " " " Elastic Limits 508 286. " " Variable " " " ll 512 287. " Repeated " " Strength 515 CHAPTER XIV. MECHANICAL TREATMENT OF METALS AND ALLOYS. 288. Qualities affected by Mechanical Treatment 517 289. The Whitworth Process. 519 290. The Lavroff Process 523 291. Rolling and Forging 5 24 292. Hydraulic Forging ; Drop Forging 525 293. Thermo-Tension ; Annealing 526 294. Cold-Working 527 295. Wire-Drawing 527 XIV CONTENTS. ART. PAGE 296. Cold-Rolling Iron ; Lauth's Process 529 297. The Dean Process, applied to Bronze 530 298. Uchatius' Method 531 299. Experiments on Compressed Bronze 538 300. Uchatius' Deductions 540 301 . Frigo-Tension 540 302. Comparison of Methods 541 303. Effect of Rolling and Hammering 543 304. Historical ; Discoveries 546 305 . History of Experiments 548 306. " " Exaltation of Elastic Limits 552 307. et " Strain Diagrams 55 1 308. " " Processes 552 309. Cold-Working Iron 555 310. " " Bronze 556 311. Conclusions 557 THE MATERIALS OF ENGINEERING PART III, NON-FERROUS METALS. OF THE XTHXVERSITY NON-FERROUS METALS. CHAPTER I. HISTORY AND CHARACTERISTICS OF THE METALS AND THEIR ALLOYS.* I. The knowledge of metals possessed by tne early races of mankind was of the most inexact and unsatisfactory character. They were probably led to seek a method of utilizing them, first, by the demands of their fighting classes. Their structures, their implements of agriculture and war, and their domestic utensils were, in the earliest stages of their race- history, of wood, bone, and stone. All races are found to have advanced to their present condition of civilization from a primitive state of barbarism, in which they were entirely ignorant of the use of metals, and knew nothing of even the simplest processes of reduction. The weapons of mankind, in prehistoric times, were at first made of hard wood, of bone, or of stone, fashioned with long and patient labor into rude and inefficient forms. As the race advanced in knowledge and intelligence, they acquired, by some fortunate circumstance, a knowledge of the methods of reducing from the ores the more easily deoxidized metals, and, still later, those which cling with tenacity to oxygen, and require considerable knowledge and skill, and special apparatus for their reduction to the metallic state ; and at a still very early period, they applied the more common and more generally useful metals in their rude manufactures. * This introduction has been in part prefaced to Part II. on Iron and Steel, as the volumes are published and sold separately. 4 MA TERIALS OF ENGINEERING NON-FERROUS METALS. It has thus happened, that mankind has passed through what are designated by the geologists as the ages of stone, of bronze, and of iron, and may be considered as having just entered upon an age of steel. The ancients, at the commencement, and immediately before the Christian era, were familiar with but seven metals. The earliest of historical records indicate that, long pre- vious to their date, some metals were worked, although with rude apparatus, and in an exceedingly unintelligent manner. Tubal Cain was an artificer in brass and in iron ; and several sacred writers refer to the use of these metals and of gold and silver, in very early times. Profane writers also present similar testimony ; and the discovery of implements of metal among the ruins of the ancient cities of Asia and Africa, and in the copper mines and other localities of North America, indicate that some knowledge of metallurgy was acquired many centuries before our era. The Hebrews were familiar with gold, silver, brass (bronze ?), iron, tin, and lead, and possibly copper and other metals. Bronze and brass were not always distinguished by ancient writers, but both alloys were known at a very early date. Phillips gives analyses * of a number of samples of the latter dating from B.C. 20 to B.C. 165, and bronze was certainly made much earlier. Zinc was known in the metallic state at some early date, while tin was known in the earliest his- toric times. The Chinese, at a time far back of even their oldest his- torical records and traditions, seem to have been workers in iron and in bronze. Evidence has been found, in Hindostan, that the inhabit- ants of the Indian peninsula, at an era of their history of which we have lost every trace, were able not only to reduce these metals from their ores by rude metallurgical processes, but that they actually constructed in metal, works which are looked upon as remarkable for their magnitude. The Chaldeans, four thousand years ago, the Persians, the * Metallurgy, 1874, p. 6. HISTORY OF THE METALS AND THEIR ALLOYS. 5 Egyptians, and the Aztec inhabitants of America, if not an earlier race, had some knowledge of the reduction and of the manufacture of metals. The " Bronze Age," in Europe, is supposed to have origi- nated in the south of England, and to have gradually spread over Europe, a knowledge of the methods of working copper and bronze finally becoming very general. The bronze age of Central America antedated that of Northern America, where the contemporaneous age was that of copper. It is probable that copper may have been the first metal worked by these early metallurgists, and that tin was next discovered and used to harden the copper, as is done at the present time. In the manufacture of bronze, the ancients became very skilful, probably long before the discovery and use of iron. The bronze implements discovered on both con- tinents have sometimes nearly the hardness and sharpness of our steel tools. It is only within a comparatively recent period, however, that metallurgy has become well understood. To insure its rapid and uninterrupted progress, it was necessary that the science of chemistry should be first placed upon a solid basis, and this was only done when, about a century ago, Lavoi- sier introduced the use of the balance, and by his example led his brother chemists to employ exact methods of re- search. 2. The valuable qualities of the 'metals used in con- struction are very greatly influenced by the presence of impurities, and by their union with exceedingly minute quantities of the other elements, both metallic and non- metallic. In the processes by which the metals are reduced from their ores and prepared for the market, there is always greater or less liability of producing variations of quality and differences of grade, in consequence of the impossibility of always avoiding contamination by contact with injurious ele- ments during these operations, even where the ore was origi- nally pure. In the time of Lavoisier, but seventeen substances were 6 MA TERIALS OF ENGINEERING NON-FERROUS METALS. classed as metals, and of these the characteristics upon which the classification was based were principally physical, and the place of newly discovered elements was long uncertain ; potassium and sodium were at first (1807) classed as non- metals. . The distinction between metals and metalloids remains somewhat indefinite, and the type metal is considered, neces- sarily, ideal. The metals are usually solid, mercury being an exception ; they are usually liquefiable by heat, but arsenic is volatile without fusing; they are generally opaque, but gold is, in very thin leaves, translucent ; they are nearly all malleable and ductile, but in very variable degrees. The metals are good conductors ; the metalloids are not. The metals are electro-positive, as a rule ; the metalloids electro- negative. Metallurgy is the art of separating the metals from the chemical combinations in which they are met in nature, freeing them from impurities with which they may be mechanically mingled, and reducing them to the state in which they are found in our markets, and in which they are adapted for application in construction. The chemical combinations from which the useful metals are obtained, are usually either the sulphides or the oxides. The common ores of iron are peroxides, either hydrated or anhydrous, and copper is generally, except in the Lake Su- perior mining region of the United States, reduced from the state of sulphide. Lead is usually found combined with sulphur, forming a sulphide known as galena. Zinc is found and mined as an oxide, as a sulphide, and also as carbonate and silicate. The sulphide of iron is rarely or never mined as an ore of iron, although abundantly distributed in the form of pyrites. The following table * illustrates the general character of the chief chemical processes employed for the purpose of reducing metals of ordinary occurrence from their ores. * Metals and Applications. G. A. Wright, London, 1878. HISTORY OF THE METALS AND THEIR ALLOYS. 7 TABLE I. REDUCTION PROCESSES IN USE. I NATIVE METALS. By mechanical means ..... ...... e.g. gold washing. By simple fusion (liquefaction) ---- e.g. bismuth. By solution in mercury .......... e.g. gold-quartz. By solution in aqueous chemicals. . e.g. gold-quartz. II. SIMPLE ORES; i. e., containing only one metal. A. OXIDES. Analytic ..... By simple heating ............... e.g. mercury, silver. f By heating in hydrogen .......... eg. nickel, iron. Single decom- J By heating in carbon oxide ....... e.g. iron (blast furnace). position ... 1 By heating with carbon (coal, \ ff .\ tin, arsenic, zinc, iron, L coke, etc.) .................. J ' ' ' ( antimony. B. CHLORIDES, FLUORIDES, ETC. Analytic ..... By heating alone ................ e.g. platinum, gold. (By heating in hydrogen .......... e.g. silver. By action of cheaper metal, etc. By (tf) wet processes ............. e.g. copper, gold. By (b) dry processes ............. e.g. magnesium, aluminium. By (c) amalgamation processes ---- e.g. silver. C. SULPHIDES. Single decom- j By heating with air ............. e.g. mercury, copper, lead. position ... \ By heating with cheaper metal, etc. e.g. mercury, antimony, lead. . followed by B converting'into chloride and) n single de- y reati as * bove ............ \*f> Sllver ' composition D. CARBONATES. Single decom- j By heating with car bon .......... e.g. zinc, sodium, potassium. followed by 4 By conver ting intochloride and) single de- y treating as S ab ove ............ r *' PP ^ composition L III. COMPLEX ORES; i. e., containing more than one metal. I. Alloy extracted by some or ) j silver-lead alloy, spie- other process, as above. ... \ ' '' ( geleisen. II. Special processes adopted for ) extraction of metals sepa- V e.g. cupriferous pyntes. rately .................... ) 8 MATERIALS OF ENGINEERING NON-FERROUS METALS. It is not the purpose of the Author to describe these proc- esses at length. In the reduction of metallic ores, the earthy impurities are separated as completely as possible by selection, and by mechanical methods, and the operation of smelting follows, during which, by chemical processes, the remaining impuri- ties, whether mechanically or chemically united with the metal are removed. Earthy matters are removed in the furnace, by the use of properly selected and skilfully pro- portioned fluxes. The ores, in their then purified condition, are deoxidized by the action of carbon, or of carbonic oxide, at high tem- peratures. The sulphides are decomposed by burning out their sulphur, as it is usually found that the affinity of sul- phur for the oxygen of the atmosphere is greater than for the metal with which it is found in combination. In these processes, high temperatures are requisite, as the chemical reaction to be secured can usually only occur satisfactorily when one or all of the substances treated are in either the liquid or the gaseous state. In the reduction of ores, the flux must be melted, as must be the silica with which it is to unite, and which it is to remove from the ore, before this desired union can take place ; and also in order that the silicate formed may flow to the bottom and out of the tap hole of the furnace. The oxide left after the removal of earthy matters must usually be brought in contact with carbon in the gaseous state as carbonic oxide, to insure its reduction ; and the finally reduced metal must be retained liquid, in order that it may be conveniently removed from the furnace. The temperatures required and allowable in reducing the various ores are widely different. Iron, copper, bismuth, lead, and nickel are reduced at a bright red heat; while ores of tin, zinc, and manganese must be made white hot zinc being volatilized in the process of smelting. The process of reduction of a metal from its ores, and its separation from earthy or metallic impurities, sometimes con- sists of a single operation, sometimes of two or more. yE (UNIVERSITY. HISTORY OF THE METALS AiVD THEIR ALLOYS. 9 3. Calcination or Roasting. The first process to which the ore is subjected, after leaving the mine, is frequently that of Calcination or of Roasting, by which the ore is disintegrated, and during which sulphur, carbonic acid, and other volatile elements and compounds are eliminated. In this process the ores are not mixed with a flux, and the temperature is not raised so high as to produce either fusion or reduction. This is found to be an economical proc- ess with nearly all ores of iron, and it is also adopted in the reduction of lead and zinc. The operation is performed either in the open air or in kilns. The former method is adopted with ores capable of withstanding somewhat elevated tem- peratures, such as the ores of iron. Roasting in heaps in the open air is conducted as follows : The ground selected is first covered with a layer of wood, or of coal six inches or more in depth. Over this is spread a layer of ore from one to two feet thick, the quantity being determined for each case by experience, and varying with the character of the ore. Another layer of fuel is added, and this is covered with another layer of ore. Alternate layers are thus added to the pile, until it has reached the desired height. The pile is then fired, and the ore, under the action of the moderate temperature produced by the smouldering fire, is slowly roasted and becomes well prepared for the suc- ceeding process of reduction. It loses its water, whether of combination or free, gives up its carbonic acid, loses a portion, if not all, of the sulphur which may have been united with it, and the disintegration produced fits it for more thorough intermixture with fluxes, and for more rapid and complete reduction. The second, and the most usually satisfactory, method, with iron ores, is that of roasting in kilns. The fuel and the ore are charged alternately into the kilns in such a manner as to become intimately mixed, and the process is similar in all respects to that which goes on in the previously described method. With kilns, however, the operation can be carried on continuously, the roasted ore being removed at the bottom, and new material supplied at 10 MATERIALS OF ENGINEERING NON-FERROUS METALS. the top as required. This method requires comparatively little space, and does not necessitate the accumulation of immense masses of ore " in stock," as does calcination by the other method. The expense of the construction of the kilns is an objection which is usually more than counterbalanced by the advantages of the process. Roasting to produce oxidation is a common process in the ordinary work of reduction of sulphides and of protoxides in special cases. The sulphides are usually converted either into sulphates or into a mixture of sulphate and oxide, of which the former often decomposes at high temperature into sulphurous acid and oxide, or oxide and basic sulphate, as with iron or zinc ores. Arsenides and phosphides are simi- larly treated. Roasting to volatilize the sulphur is a common method of treatment of iron pyrites, which yield sulphur freely by partial decomposition. Carbonates and hydrated ores are also thus treated to drive off carbonic acid and water. The most common process of reduction of ores is a refined method of reducing by roasting in a deoxidizing atmosphere, and in contact with other reducing agents, as carbon. The metals which are treated of in this work are all usually found only in a state of combination with either oxygen or sulphur, with the single exception of copper, which is often found native, and deposits of which are sometimes very extensive, furnishing the market with large quantities of that metal. These oxides and sulphides are mixed with other minerals of less valuable, of valueless, or even often of in- jurious, character. It becomes usually necessary to melt the " ores," as these minerals are called, to effect the separation and reduction of the metal. This operation is called " smelt- ing." The "wet" or " humid " processes of reduction are but little practised in ordinary metallurgical work, although those methods and electrolysis are occasionally found useful and commercially economical. The melting of common ores is not usually practised, except as a sequel to an earlier roasting process, except in the case of oxides of iron, which are often smelted without HISTOR Y OF THE ME TALS A ND THEIR ALLO YS. 1 1 calcination or roasting except such as occurs within the furnace previous to fusion. When melting does take place, it results in reduction of the metal and its separation from the gangue that may have accompanied it. This separation is usually accomplished partly by the formation of a fusible slag, by union of the gangue with a flux, which is either siliceous, aluminous or calcareous, according to circumstances. Melting to reduce the ore is effected by the combined action of heat and of chemical affinity, and by the use, with oxides generally, of carbon both as a fuel and as a reducing agent. Sulphides of other metals than iron are reduced by melting with that metal. Smelting with oxidation some- times takes place, as in separating metals, or removing sulphur, or in the manufacture of litharge, a lead oxide ; this sub- stance is also used as an oxidizing agent with sulphides of other metals. Melting to effect solution is sometimes practised to secure a separation of compounds into constituent elements or com- pounds. Thus fused lead oxide dissolves some of the sul- phides and many oxides. Lead itself is used in dissolving silver and gold out of some of their ores. The alkaline car- bonates dissolve the oxides of the metals, and borax, fluor- spar, and other substances similarly used as fluxes act in the same manner when employed in the production of slags. The silicates of alkalies and alkaline earths perform the same office as the ther fluxes, and are especially valuable in the treatment of oxides, as solvents both of some oxides and of the gangue ; the most easily reduced oxides are dissolved by the silicate, and go into the slag, while the less readily reduci- ble oxides of the compound give up the metal.* Slags are necessarily more fusible than the metal to be reduced. Melting is often a process preliminary to volatilization, as in the reduction of ores of arsenic and of zinc, or to separa- tion by liquefaction and crystallization. 4. Smelting". The final process of reduction, that of Smelting, which usually requires still higher temperature, and which immediately succeeds calcination, is conducted in * Watts. 12 MATERIALS OF ENGINEERING NON-FERROUS METALS, various ways, the outlines of which will be given in those chapters relating to the several metals. 5. Fluxes, are used in nearly all of the metallurgical processes, and their characteristics are determined by the special requirements of each case. Fluxes are, as the name (from fluo, to flow) indicates, sub- stances which assist in reducing the solid materials in the smelting furnace to the liquid state, forming a compound known as slag, or sometimes as cinder. It frequently happens that two substances, having a pow- erful affinity for each other, will unite chemically, when brought in contact, and fuse into a new compound at a much lower temperature than that at which either will melt alone. Silica fuses only at an extremely high temperature, if iso- lated, or if heated in contact with bodies for which it has no affinity ; but, if mixed with an alkali, as potash, soda, or lime, the mixture fuses readily. The two first-named alkalies are too expensive for general use in metallurgy ; but the lat- ter is plentifully distributed, as a carbonate, and it is, there- fore, the flux generally used in removing silica from ores, by fusion. Borax similarly unites with oxide of iron to produce a readily fusible glass ; and it is, therefore, often used by the blacksmith as a flux when welding iron. Quartz sand is also used by the blacksmith for precisely the same purpose. Being composed almost purely of silicic acid, it forms a readily fusible silicate with the oxides of iron, and it is used wherever the mass of iron is of considerable size, and is capable of bearing, without injury, the high temperature necessary for its fusion. Fluor-spar, a native fluoride of calcium, has been fre- quently and extensively used as a flux. Its name was given to it in consequence of that fact. It is a very valuable fluxing material, and is used where the expense of obtaining it does not forbid its application. It has special advantages arising from the fact that it is composed of two elements, both of which perform an active and a useful part in the removal of the non-metallic constituents of ores. In the removal of sulphur HISTORY OF THE METALS AND THEIR ALLOYS. 13 and phosphorus from iron, it also possesses the great advan- tage that the resulting compounds produced by its union with those elements are gaseous, and pass off up the chimney, in- stead of remaining either solid or liquid in the furnace and contaminating the iron by their contact. Since the aim, in selecting a flux, is usually to form, with the impurities to be removed, a readily fusible glass, such materials are selected, in each case, as are found, by analysis or by trial, to unite in those proportions which produce such a compound. The "slag" thus formed should usually be a compound silicate of lime and alumina, as free as possible from refractory substances, like magnesia, and from the oxides of the metal treated. The flux used, therefore, where an ore contains excess of silex, is a mixture of lime and alumina as, for example, limestone and clay. Where the ore already contains alumina, limestone only may be needed. In the reduction of iron ores, limestone is very generally the only material added as a flux. 6. The Fuels used in engineering and metallurgy are con- sidered very fully in Chapter IV., Part I., of this work. 7. Mechanical Processes. Metallurgy includes both mechanical and chemical processes. The former consist in crushing and washing ores, or the gangue with which they are associated, to render the processes of reduction or of separation more easy, complete, and economical. The " stone- breaker," or " rock-crusher," is the form of crushing apparatus used for breaking rock into pieces of fixed size. It often consists of an arrangement of vibrating jaw, J (Fig. i), hung from the centre, K, and operated by a knee-joint, GG, the connecting-rod of which, E, is raised and depressed by a crank, C, driven by a steam engine. A fly-wheel, B, gives regularity of motion, and stores energy needed at the instant when the squeeze occurs. Steel or cast-iron faces, PP, receive the wear. The breadth of opening at /, which de- termines the maximum size of pieces crushed, is adjusted by a wedge at O W y set by a screw at N. The jaw is pulled back 14 MATERIALS OF ENGINEERING NON-FERROUS METALS. by a spring R. Many modifications of this, the Blake crusher, are now made. Stamps consist of heavy weights carried at the ends of vertical rods, which are lifted either by cams on a continuously revolving shaft, or by the ac- tion of a steam piston. The former are the older, and for many kinds of work the most effective style ; the latter are, however, found vastly more economical for other cases, as in the crush- ing of some of the copper- bearing rock of the Lake FIG. I.-STONE-CRUSHER. Superior district. Washing machinery is largely used in silver mining and reduction, and less generally in working the ores of the " use- ful " metals. It takes many forms, according to the kind of work to be done ; this is usually the washing of earthy matter from harder ores or the separation of heavy masses from an earthy mass in which it is imbedded. 8. The Working of Metals, as an art, antedated, un- questionably, the very earliest historic periods, and introduced the " age of bronze." The first metal-work was done in gold, silver, copper, bronze, brass, lead, and iron, and possibly tin. The East Indians, the Egyptians, the early Greeks, and per- haps other nations, were familiar with methods of working these metals and alloys, and are said to have been conversant with a now unknown art of hardening and tempering bronze, to give cutting edges on knives and weapons, which were only equalled by those of steel. Copper was much used during the Middle Ages, and from A.D. iioo to 150x3 espe- cially, for a great variety of objects. Bronze was the most common material for works in art among the older nations. The metals were worked both by casting and by the " repoussf method. The earliest castings were solid, and the art of economizing cost and weight by " coring out " the inner portions was one of later introduction. The first HISTORY OF THE METALS AND THEIR ALLOYS. I 5 " cores " in bronzes were of iron, and were left in in the cast* ing ; still later, removable clay and wax cores were used. The finest Greek art-castings and those of the Romans, and later the Italian artists, were made by the method called, by French workers in, bronze, that " ct cire perdue." The statue or other object was first roughly modelled in clay, and in size slightly less than that proposed for the finished piece. On this clay model was laid a coating of wax, which was worked to exactly the intended finished size and form, and was frequently even given the smoothness of surface desired in the finished casting ; this formed a thin skin over the clay. A clay, or earthy, wash was next applied, covering the wax surface, and over this was placed a thick and strong mass of clay, worked on in soft state and allowed to dry and set. The whole was then baked slowly; the wax melted and flowed out from between the two masses of clay, leaving a space into which molten bronze was finally poured to form the casting. The two parts of the clay mould were secured together by stays of bronze which were built, or afterward driven, into both parts, and thus connected them together. When the casting had cooled, the clay was torn away from the outside and removed from the interior of the bronze ; the surface was finished up as required, and the work was done. The finest antique bronzes were thus made. The hammered, or " repousse" work of the Greeks was wonderfully perfect at a date which is supposed to have been earlier than that of their large castings. The first efforts in this direction were rude ; the sheet metal was hammered into shape over blocks of wood, which had been roughly given the desired form. Later, a bed of pitch, or of soft kinds of cement, was prepared, and the sheets hammered into form by striking them on the back side, the bed yielding to the blow and thus allowing the metal to assume the desired shape without being broken by the hammer or by the punch used. The work was often reversed and the final finish given on the front side. This method produced some of the largest and the finest of the ancient Asiatic bronzes, and fine work in gold, silver, and copper. The Greeks excelled in this 1 6 MATERIALS OF ENGINEERING NON-FERROUS METALS. method of metal-working. In many cases, the thickness of the metal was reduced nearly to that of paper, without injury to its surface. The Siris bronzes of about B.C. 400 are of this kind. Tin was probably worked into vess.els for domestic use by the natives of Cornwall before the settlement of the country by the Romans. Lead was used throughout Europe, in the mediaeval period, in sheets for roof-coverings, and cast into objects of complicated form. Specimens remain of the former, exhibiting its great durability when exposed to the weather. Like the modern Chinese and Japanese artists, the ancient workers in metal used gold and silver to adorn and give relief to their castings in bronze. Mirrors, of fine surface and thus ornamented, are common among collections of the products of Greek art. The bronzes of the Italian artists of the Middle Ages are remarkable for their beauty as art work in metal, as well as for their beauty of design ; even their work in iron is famous for its unexcelled beauty and the skill exhibited in forging it. Modern work has not equalled that of the Middle Ages, or even that of the early Greeks. 9. Metal is the name applied to above fifty of the chem- ical elements. The larger number of the metals are but little known, and many are found in such extremely minute quantities, that we are not well acquainted with either their chemical or their physical characteristics. Some approach the non-metallic elements so nearly in their properties, that they are placed, sometimes in the one class, and sometimes in the other. Very few of the metals are well fitted for use in construction ; but, fortunately, those few are comparatively widely distributed, and are readily reduced from their oxides or sulphides, in which states of combination they are almost invariably found in nature. 10. The " Useful Metals " are iron in its various forms of cast iron, malleable or wrought iron, and steel copper, lead, tin, zinc, antimony, bismuth and nickel, and occasionally aluminium and rarer metals are used for similar purposes. From this list of metals, and from their alloys, the engi- HISTORY OF THE METALS AND THEIR ALLOYS. IJ neer can almost invariably obtain precisely the quality of material which he requires in construction. He finds here substances that exceed the stones in strength, in durability under the ordinary conditions of mechanical wear, and in the readiness and firmness with which they maybe united. They are superior to timber of the best varieties in strength, hard- ness, elasticity and resilience, and have, in addition, the im- portant advantages, that they may be given any desired form without sacrificing strength, and may be united readily and firmly to resist any kind of stress. By proper selection or combination, the engineer may secure any desired strength, from that of lead, at the lower, to the immense tenacity of tempered steel, at the upper limit. He obtains any degree of hardness, or fusibility, and almost any desired immunity from injury by natural destroy- ing agencies. Elasticity, toughness, density, resonance, and varying shades of color, smoothness, or lustre, may also be secured. 11. The Laws Governing Distribution of the Ores of the metats are comprehended in the science of geology. The detection of their presence in any locality, and bringing them to the surface of the ground, free from the foreign earthy substances which accompany them, is the work of the min- ing engineer, and of the miner. The "reduction" of the metals from ores, by chemical and mechanical processes, con- stitutes the business of the metallurgist. The engineer takes the metals as they are brought into the market, and makes use of them in the construction of permanent or movable structures. 12. The Requirements of the Engineer include some acquaintance with the general principles, and with the ex- perimental knowledge, which are to be obtained by the study of geology; of mining, and of metallurgy, to aid him in select- ing the metals used in his constructions ; since their quali- ties cannot always be determined by simple inspection, and it is not always possible to subject them to such tests as he may consider desirable before purchasing. In such cases, a knowledge of the localities whence the ores were obtained, 1 8 MATERIALS OF ENGINEERING NON-FERROUS METALS. familiarity with the processes of manufacture, and with the nature of the materials employed by the metallurgist, coupled with a knowledge of the effects of various foreign substances upon the quality of the metal, may enable the engineer to judge with some accuracy what metal will best suit his pur- poses, and what will be likely to prove valueless. He is also thus enabled to judge, should the purchased material prove defective, where the defect in quality originated, and to place the responsibility where it belongs. The student will seek this knowledge in special works on geology and metallurgy. But brief reference can be made to these subjects here. All the metals possess, as a whole, a number of properties which define the class, although few of these properties are common to all. The metals all unite chemically with oxygen to form basic oxides, and some of them take higher proportions of oxygen, forming acids. All metals are capable of similarly uniting with chlorine. All are capable of fusion and lique- faction at certain temperatures, fixed for each, which are usually high. Mercury, however, is liquid at ordinary tem- peratures. The metals are also capable of vaporization, and their vapors have some physical characteristics quite different from those of the solid metal. Thus, silver, white when solid or liquid, becomes blue as a vapor; mercury vapor is color- less, potassium is green. All are opaque, except in exceed- ingly thin films, when some become apparently translucent. Gold transmits green light, mercury blue, and silver remains opaque in the thinnest leaf yet made. 13. The Special Qualities of the Useful Metals which give them their importance as materials of construction are : their strength, hardness, density, ductility, malleability, fusibil- ity, lustre, and conductivity. Strength, or the resistance offered to distortion and fract- ure, is their most valuable quality. The strength of metals and alloys in general use has been very carefully determined by experiment, and will be given hereafter. Of the metals in our list, lead is the least tenacious, and steel is the strongest. HISTORY OF THE METALS AND THEIR ALLOYS. 19 14. The Non-Ferrous Metals, which are to-day of com- paratively little importance to the engineer in the construction of machines or of structures, and which have been so generally superseded by iron and steel in every department of art, were, in earlier times, in some cases, as copper, tin, lead, the most common materials of construction. The three just mentioned were known in prehistoric times, and the Greeks were also familiar with mercury, as well as with iron. Valentinus dis- covered and described antimony in the I5th century, and bismuth and zinc became known at about the same time or a little later. Brande discovered arsenic and cobalt about the middle of the 1 8th century, and Ward discovered cobalt.* Cronstedt discovered nickel and Scheele manganese in 1774, and tungsten was prepared in 1783 by the brothers D'Elhu- jart. Palladium, rhodium, indium and osmium were isolated and described by Wollaston and others in 1803. The alkaline earths, recognized as oxides by Davy in 1807-8, were soon after deoxidized, and potassium and sodium became known. Aluminium and magnesium were separated in 1828 and 1829, respectively by Wohler and by Bussy, and cadmium had already been discovered by Stromeyer in 1818. The rarer and more unfamiliar metallic elements were found later. The properties of these metals have been referred to in a general way in an abridged account of them given in Part II. of this work. A more detailed account of those used in con- struction will occupy the greater part of this volume. The following is a resume of the general characteristics of these metals. 15. The Relative Tenacities are approximately as below, lead being taken as the standard. TABLE II. RELATIVE TENACITIES OF METALS. Lead i.o Tin 1.3 Zinc 2.0 Worked copper 12 to 20 Cast iron 7 to 12 Wrought iron 20 to 40 Steel 40 to loo * Encyclopaedia Britannica, 1883, art. Metals. 20 MATERIALS OF ENGINEERING NON-FERROUS METALS. No two pieces of metal, even nominally of the same grade, have precisely the same strength. The figures can therefore only represent approximate ratios, as every variation of purity, structure, or even of temperature, is found to affect their strength. Cast metal is usually weaker than the same metal after having passed through the rolls or under the hammer ; those which can be drawn into wire are still more considerably strengthened by that process. Metals are stronger at ordi- nary temperatures than when highly heated, and " annealing " is found to reduce the strength of iron and steel, although frequently increasing their ductility, and produces an op- posite effect on copper and its alloys. " Hardening," pro- duces the contrary effect. The presence of impurities and the formation of alloys produce changes of strength, some- times increasing, sometimes diminishing it. Copper alloyed with tin or zinc, in certain proportions, is strengthened ; and the addition of a small percentage of phosphorus to the alloy has a marked effect in increasing its tenacity and ductility. 16. Hardness varies in the metals as considerably as their tenacity, and, like the latter quality, is greatly influenced in the same metal by very slight changes, either physical or chemical. Thus metals are hardened by cold hammering and softened by sudden change of temperature. The addition of scarcely more than a trace of impurity often produces a marked change in the degree of hardness of metals. The scale of hardness, according to Gollner,* is as follows: Soft lead. Tin.. i 2 Hard lead 3 Copper 4-5 Alloy for bearings (C.,8 5 ; T., io;Z., 5). 6 Soft cast iron 7 Wrought iron 8 Cast iron 10-11 Mild steel 12-13 Tool " blue 14 " " violet 15 " " straw 16 Hard bearings (C, 83; Z., 17) 17 Very hard steel 18 * Tech. Blaetter ; London Engineering, June I, 1883, p. 519. QUALITIES OF THE METALS AND THEIR ALLOYS. 21 The hardness of metals, as determined by Dumas, is exhibited in the following table of their order. TABLE III. HARDNESS OF THE METALS. Titanium Manganese Scratch steel. RhodTuT 1 Scratch S lass Platinum Nickel Palladium Cobalt Copper Iron - Scratched by Gold Silver Tellurium Scratched by ' Calc Spar. Antimony Zinc Scratched by Bismuth .L,eaa the nail. Cadmium Tin J Potassium Sodium Soft as wax. Mercury, Liquid. 17. Conductivity, or their power of transmitting molecu- lar vibrations of either heat or electricity, is another property of the metals, upon which is founded many useful applications, Of the " useful " metals, copper has by far the highest conductivity, and is only second in this respect to gold and silver, the best known conductors. Its conductivity is greatly reduced by the presence of foreign substances. The powers of conduction for heat and electricity seem to have very similar relative values. Conductivity is reduced by increase of temperature and by presence of impurities. The following table of relative conductivities was deter- mined by the experiments of Despretz, and very closely con- firmed by Forbes. TABLE IV. RELATIVE THERMAL CONDUCTIVITIES OF METALS. Gold 1,000 Silver 973 Copper 878 Iron 374 Zinc 360 Tin... 304 Lead 180 Marble 25 The electric conductivities obtained by Becquerel, and the 22 MATERIALS OF ENGINEERING NON-FERROUS METALS. thermal conductivities given by Wiedmann and Franz, are as below : * TABLE IVtf. CONDUCTIVITIES OF METALS. ELECTRIC. THERMAL. In Vacuo. In Air. Silver . . T.OOO I,OOO '748 548 240 154 84 79 T,OOO '736 532 236 145 840 85 18 Copper. . ,ppci . ' commercial . . 915 649 140 79-3 82.7 Gold Brass Tin . .... Platinum Lead Bismuth The resistance to the voltaic current has been found by Mr. K. H edges f as follows, wire and foil being used, and strength of the current so adjusted that on increasing it 20 per cent, the metal would fuse. The experiments continued 24 hours and the temperature was 69 F. (21 C.) TABLE V. RESISTANCES OF METALS TO ELECTRIC CURRENTS. METAL. Before Heating. Change in 24 Hours. I. Commercial tin, 2. Lead, soft wire 0.815 Ohms. 0.835 o.Sio 0.860 0.800 0.835 0.820 0.003 0.005 + o.ooo + 0.000 0.160 + o ooo + 0.0008 3. Copper, soft. . . 4. Tin-foil, pure.. 5. Tin and lead. . . 6. Aluminium ("A 7. Aluminium and ilbo ") alloy foil tin RESISTANCES AS MEASURED. * Part II., p. 8, 10. f Brit. Assoc. Reports, 1883, Sec. G. QUALITIES OF THE METALS AND THEIR ALLOYS. 2$ Commercial copper (Rio Tinto), has been found to have, in some cases, but one-seventh the conductivity of pure copper. Conductivity is reduced by increase of temperature, ac- cording to Forbes, and at rates varying with the character of the metal. M. Benoit has measured the electrical resistance of various metals at temperatures from o to 860 C. The mean of the figures obtained is given in the following table, the second column giving the resistance in ohms of a wire 39.37 inches (i metre) long, and having a cross section of 0.03 inch (0.2 sq. cm.), and column three the same quantity in Siemens units. Column four gives the conductivity compared with silver : TABLE Va. METAL. OHMS. SIEMENS. Silver A .OI54 0161 IOO Copper A OI7I OI7Q Silver A (i) .oicn O2OI 80 Gold, A .O2I7 O227 71 Aluminium A O^OQ OQ2J. 4Q 7 Magnesium H .042^ O44^ 06 4 .(x6^ O^QI 27. *, Zinc H OCQ 1 O62I 2C Q Cadmium, H .068=; O7l6 *P*V 22 ; Brass A. (2) .0601 O72T 22. 1 Steel A IOQQ II4Q 14 Tin 1161 1214 j 2775 5.8o .9564 I.OOOO 1.61 A, annealed; H. hardened; (i) silver .75; (2) copper 64.2, zinc 33.1, lead 0.4, tin 0.4; (5) copper 90, aluminium 10 ; (4) copper 50, nickel 25, zinc 25. These results, are all taken at o C., and agree closely with those obtained by other observers. The resistance increases regularly for all metals up to their points of fusion. This 24 MATERIALS OF ENGINEERING NON-FERROUS METALS. increase, however, differs for different metals. Tin, thallium, cadmium, zinc, lead, are found to vary similarly; at 200 to 230 their resistance has doubled. The resistance of iron and steel doubles at 180, quadruples at 430, and at 860 is about nine times that at o. Palladium and platinum increase much less, their resistance becoming twice that at o C, at 400 to 450. Gold, copper, and silver form an intermediate group. In general conductibility decreases more rapidly the lower its point of fusion. Iron and steel are exceptions to this rule. In alloys the variation is less than in their constituents, and this is especially the case with German silver. The thermal conductivity of brass was found by Isher- wood to be 556.8 thermal units (British) per hour per square foot and per i Fahr., and to vary at the difference of tem- perature. Silicon-bronze may be given a conductivity but little less than that of copper, but its tenacity then diminishes con- siderably; that having 95 per cent, the conductivity of copper, has but one half the strength of that of which the conductivity is 25 per cent. 18. The Lustre of these metals is measured by their power of reflecting light. Thus, according to Jamin, silver may reflect 0.9 of the light sent between surfaces of mirrors made of that metal ; after ten normal reflections it yields from 0.24 to 0.48, the former figure being that for violet, and the latter for red light. The figures for speculum metal are 0.6 to 0.7, 0.006 and 0.035 ; those for steel, 0.6, 0.006, and 0.007. Estimating weights of metal in various forms as used by the engineer is a simple operation. Thus : if d diameter of a circular section, or the minor diameter of an ellipse ; d' = major diameter of ellipse ; / = length of piece, section uniform ; b = breadth ; k a constant ; W ' total weight. QUALITIES OF THE METALS AND THEIR ALLOYS. 2$ The weight of any piece of uniform section is W '= kd*l for cylindrical bars ; = kdd'l " elliptical sections ; = kbdl " rectangular sections. The values of k when / is in feet, other dimensions in inches and Win pounds, are VALUES OF k IN W '= kdd'l. W= kbdl. 2.906 j 700 Iron wrought 2 618 3-7-J-3 3 888 4QCQ Steel, soft 2.670 1. , J.OO For pipes, W= k(d? df) when d^d 2 represent the inner and outside diameters in inches. To obtain weights in kilogrammes when measures are in centimeters, multiply the above by 0.00241. The " metallic lustre " is a property of the metals almost peculiar to them, and constitutes one of their marked charac- teristics. Polished steel, and an alloy of copper and tin known as speculum metal, burnished copper and aluminium, as well as the precious metals, gold and silver, exhibit this beautiful and peculiar lustre very strikingly. Tin, lead, and zinc, are lustrous, but they are not capable of taking a sufficiently high polish to exhibit this quality in such a degree as the metals first named. 19. The Specific Gravities of the commercial metals are' as follows : THE DENSITIES OF PURE METALS according to Fownes,* are * Chemistry, loth eel., p. 297. 26 MATERIALS OF ENGINEERING NON'-FERRO US METALS. TABLE VI. SPECIFIC GRAVITIES OF PURE METALS. (Water at 60 F. (15-5 C.) = i.) Platinum 21 . 50 Indium 21.15 Gold 19-50 Tungsten 17 . 60 Mercury .... J 3 59 Palladium u . 80 Lead *i-45 Silver 10.50 Bismuth 9-9 Copper 8 . 96 Nickel 8.80 Cadmium 8 . 70 Molybdenum 8 . 63 Cobalt 8.54 Manganese 8.00 Iron 7-79 Tin 7.29 Zinc 7. 10 Antimony 6 . 80 Tellurium 6.11 Arsenic 5.88 Aluminium 2.67 Magnesium 1.75 Sodium 0.97 Potassium o. 87 Lithium o. 59 For the purposes of the engineer, the densities and the weights per unit of volume of commercial materials are the data desired. The following table gives such a set of figures. As is seen by comparing the tables, authorities differ some- what in these figures. TABLE VII. WEIGHTS AND DENSITIES OF COMMERCIAL METALS. NAME. S. G. LBS. IN CU. FT. KILOG'S IN CU. M. 2.56 1 60 2,560 sheet 2.67 167 2,670 Antimony cast 6.7 418 6,700 Bismuth, " - 9.8 614 9,800 Brass * cast . . . 8.4 525 8,400 " sheet . . 8.5 S3 2 8,500 <4 wire 8.54 eo-3 8,540 Bronze * (ordinary) . . 8.4 C i24 8,400 Copper,* bolts 8.85 548 8,850 " cast 8 60 c-37 8,600 " sheet 8.88 54Q 8,800 ' ' wire 8.88 550 8,800 Gold, hammered . . 10 4 I.2O5 10,400 ' ' standard 17.65 I,TO3 17,650 Gun metal (bronze) . . S.I*'* 510 8,153 QUALITIES OF THE METALS AND THEIR ALLOYS. 2J TABLE VII. Continued. NAME. S. G. LBS. IN CU. FT. KILOG'S IN CU. M. Iron cast from . . . 6 Q55 4 k = 0.10687 + Q.0000547/ + o.ooooooo428/ 2 j" for the Fahrenheit and Centigrade scales respectively. For platinum he obtains : k = 0.0328 + o.ooooo3022(/ 32) + 0.000000000009 (/ 32)', k 0.0328 + 0.00000544/ + 0.0000000000 1 6/ 2 , (I) or, very nearly, k = 0.03208 + 0.00000304 (t 32) ) k 0.03208 + 0.00000547/ 1 f * Journal Franklin Institute, August, 1882. 34 MATERIALS OF ENGINEERING NON-FERROUS METALS. The figures given in Table XI. are mean values be- tween the temperatures of freezing and of boiling, of the quantity of heat, in thermal units, required to produce a change of temperature of one degree. Their values have been shown by Dulong and Petit to increase with the rise of temperature, as does the specific heat of water itself. When melted their specific heats are greater than when solid. The specific heats represent the number of units of water which would be raised in temperature one degree by the addition of the amount of heat which would raise one unit of weight of the metal one degree. Specific heat is sometimes called " Capacity for heat." 25. The Expansion of the Metals by increase of tem- perature is exhibited by the following table of coefficients of linear expansion. The figures represent the extension, in parts of its own length, of a bar of the given metal during a rise in tempera- ture from the freezing to the boiling point of water. TABLE XII. LINEAR EXPANSIONS OF SOLIDS. EXPANSION BETWEEN 32 F.(oC.)AND2I2 F.(lOOC.) AUTHORITY. Glass o 000872 to o 000918 Lavoisier and Laplace. 0.000776 to 0.000808 Roy and Ramsden. Copper o 001712 to o 001722 Lavoisier and Laplace Brass o 001867 to o 001890 o 001855 to 0.001895 Roy and Ramsden. Iron . . O OOI22O to O OOI235 Lavoisier and Laplace Steel (untempered) . . . " (tempered) 0.001079 to 0.001080 o 001240 <( t ( Cast Iron O OO 1 1 09 Roy and Ramsden. Lead o 002849 Tin o 001938 to o 002173 < Gold o 001466 to o 001552 o 000884 Zinc o 002976 Daniell QUALITIES OF THE METALS AND THEIR ALLOYS. 35 Chancy gives* the following values of the coefficients of linear expansion, at ordinary temperature, as recalculated by him, and corrected for the author, from selected data, for the Standards Office of the British Board of Trade. TABLE XIL*. EXPANSIONS OF SOLIDS. FOR i F. FOR r C. AUTHORITY. 0.00001234 O.OOOO222I Fizeau. cryst 0.00000627 0.00001129 Brass ca-t 0.00000957 0.00001722 Sheepshanks " plate 0.00001052 0.00001894 Ramsden. " sheet 0.00000306 o. 00000^50 Kater. Bronze, Baileys, Cop., 17 ; tin, 25 ; zinc, i. 0.00000986 O.OOOOOQ7S; 0.00001774 0.00001775 Clarke. Hilgard. Coooer 0.00000887 0.00001596 Fizeau. Gold 0.00000786 O.COOOI4I5 Chandler & Roberts. o 00000356 O.COOOO64I Fizeau. Lead 0.00001571 0.00002828 Mercury (cubic expan.) 0.00009984 o 00004695 o 00017971 0.00001251 Regnault & Miller. Fizeau. Osmium . . ........ 0.00000317 0.00000570 tt Palladium 0.00000556 O.OOOOIOOO Wollaston. Pewter o 00001129 0.00002033 Daniell. Platinum 0.00000479 0.00000863 Fizeau. '* CfO ; indium, 10. . . . " 85; " 15...- Silver 0.00000476 0.00000453 0.00001079 0.00000857 0.00000815 0.00001943 it Chandler & Roberts. Tin 0.00001163 0.00002094 Fizeau. 0.00001407 0.00002532 Baeyer. " 8 tin i 0.00001496 0.00002692 Smeaton. These coefficients are not absolutely constant, but vary with the physical conditions of the metals. They are not the same with the same material in its forms of cast, rolled, ham- mered, hardened, or annealed metal. The value of the co- efficient of expansion also increases slightly with increase of temperature. To determine the length, L r , of a bar at any given tem- perature, /', knowing its length, Z,, at any other temperature, /, we have the formulas : * Calculations of densities and expansions ; report by the Board of Trade ; printed for the House of Commons, London, 1883. 36 MATERIALS QF ENGINEERING NON-FERROUS METALS. , I + at T8o , for Fahr. scale, L(I + ^-} T , \ lOOj , , 2J = ^_ for Cent, scale, at 100 where a is the coefficient given above. TABLE XIII. EXPANSIONS OF VOLUME. (3) .. (4) PER DEGREE CENT.* o C. (32" F.) to ioo r ' C. (212 F.). Glass .00002 to .00003 .002 to .003 Iron 000035 to 000044 0035 to 0044 Copper. . .000052 to 000057 0052 to .0057 Platinum .000026 to .000029 .0026 to .0029 Lead 000084 to 000080 0084 to 0089 Tin .000058 to 000069 .0059 to .0069 Zinc .OOOO87 to OOOOQO .0087 to .0090 Brass . . 000053 to 000056 0053 to 0056 Steel .000032 to 000042 .0032 to .0042 Cast Iron about ooocm .00^1 These results are partly from direct observation, and partly calculated from observed linear expansion, which is one-third the cubical expansion. 26. The Fusibility of the Metals, or their property of be- coming liquid at a temperature which is always the same for the same metal, is a quality which has an important bearing upon their useful applications in the arts. All solids which do not undergo decomposition by heat before reaching that temperature have definite "melting points." The metals differ more widely in their temperatures of Abridged from Watts's "Dictionary of Chemistry. QUALITIES OF THE METALS AND THEIR ALLOYS. 37 fusion than even in density. Solidified mercury melts at nearly 40 below zero, Fahr. ( 40 Cent.) ; while platinum requires the highest temperature attainable with the oxy- hydrogen blow-pipe. The more common metals fuse at tem- peratures quite readily attainable, although none of them melt at temperatures approaching those ordinarily met with in nature. Some of the metals may even be readily volatilized, and probably all are vaporized, to a slight degree at least, at very high temperatures. Mercury boils at 330 Cent. (626 Fahr.). Zinc can be distilled at a bright red heat, and copper and gold are known to give off minute quantities of vapor at temperatures frequently occurring during the process of man- ufacture. The low temperatures of fusion of tin, lead, bismuth, and antimony, allow of their being readily applied as solders, either alloyed or separately. Cast iron, copper and its alloys, and other metals, melt at temperatures which are easily reached, and the iron and the brass founders are thus enabled by the process of moulding and casting, to produce the most intricate forms readily and cheaply, and thus, when desired, to obtain large numbers of precise copies of the same pattern. The melting points of some of the more important metals are as follows : TABLE XIV. TEMPERATURE OF FUSION OF COMMERCIAL METALS. FAHR. CENT. Mercury . .... 39 39 Tin 420 216 Bismuth . .... 400 254 Lead 7 630 332 Zinc 700 371 Silver 1,280 693 1,870 1,021 2,550 1,118 2,750 1,510 4,000 (?) 2,201 (?) 38 MATERIALS OF ENGINEERING NON-FERROUS METALS. The temperatures of fusion of pure iron, or of wrought iron, are very high, and are not precisely known, no means of accurate measurement having yet been applied to their determination. The following very complete table will serve for reference in more extended work.* TABLE XV. MELTING POINTS OF PURE METALS. FUSIBLE ABOVE RED HEAT. FUSIBLE BELOW RED HEAT. F. C. F. C. Silver . . . . + 1873 + 1023 1996 1091 2Ol6 IIO2 2786 1530 ? Highest heat of the forge. Do not melt in the forge. Fusible only in Oxyhydrogen flame. Mercury . . .... -39 + 101.3 144-5 207.7 356 442 442.5 497 56i 617 6i5 (?) 773 red -39 -8 + 38.5 62.5 97.6 1 80 227.8 228 259 294 325 324 412 heat. Copper . . Rubidium Gold Potassium Cast Iron Sodium Pure Iron, "1 Nickel, Cobalt, \ Manganese, Palladium, Molybdenum, 1 Uranium, Tungsten, Chromium, Titanium, Cerium, Osmium, Iridium, Rhodium, Platinum, Tantalum, Lithium Tin Cadmium Bismuth j Thallium Lead Arsenic .... Zinc Antimony Latent Heat. In passing from the solid to the liquid state, a certain amount of heat disappears, being expended in producing this change of physical conditions. Latent Heat, as this is called, varies in amount with dif- For approximate values of temperatures of fusion of alloys, see later. QUALITIES OF THE METALS AND THEIR ALLOYS. 39 ferent substances. In Table XVI. are the latent heats of several, as obtained by M. Person, expressed in thermal units.* TABLE XVI. LATENT HEATS OF METALS. CENT. FAHR. Tin 14.25 2<$. 6? Bismuth 12.64 22.75 Lead . ... c -17 9.67 Water 7Q.25 142.65 Silver 21 O7 V] .&\ Cadmium ... i-?. 66 24- 5Q 27. Chemical Character. Chemically, the metals exhibit the same variation of properties as physically, and the line of demarcation between the metals and the metalloids is no more definitely fixed. They are acid or basic in combination, and resemble the metalloids more or less nearly in chemical action, according to the proportion as well as the nature of the elements with which they combine. Their oxides are usually basic, but often acid. The alkaline metals unite with oxygen with great rapidity to form alkaline oxides ; the com- mon " useful " metals are oxidized readily, but less freely than the preceding, and gold, silver, platinum, and others, have little affinity for oxygen, and do not easily corrode. Nearly all metals combine freely with sulphur, and their sulphides form, in some cases, extensive deposits which are worked for the market. 28. Alloys are formed by fusing together two or more metals. In the alloys, metallic qualities and chemical prop- erties are not always completely altered or masked, as is the case in chemical combinations with the non-metals. * This thermal unit is the quantity of heat required to raise the temperature of unity in weight of water at maximum density, one degree in temperature. For values of constants, relating to the non-ferrous metals, expressed in " C. G. S." units, see Appendix, Part I. 40 MATERIALS OF ENGINEERING NON-FERROUS METALS. The physical properties of the alloys are, however, some- times quite different from those of the constituent metals, notwithstanding the fact that the compounds formed are apparently not definite, as in cases of purely chemical combi- nations. It would appear probable that the force of chemi- cal affinity performs some part in the formation of the alloy. It is not improbable that a definite compound is usually formed which either dissolves, or is dissolved in, any excess of either constituent which may be present. Examples of alloys are seen, in gold and silver coins, in which the precious metals are hardened by alloying them with copper, to give them greater durability. Copper is too soft and tough to allow of its being conveniently worked, and it is, therefore, for most purposes, alloyed with tin or zinc, and these alloys bronze and brass are, by varying the propor- tions of the metals used, adapted to a wide range of useful application. Alloys of copper and tin exhibit strikingly the fact, noted above, that the alloy may have widely different properties from either constituent. Speculum metal is composed of 33 per cent, of tin fused with 67 per cent, of copper. Its color is nearly white, it is extremely hard, exceedingly brittle, and takes a magnificent polish. The latter property gives it value for reflectors of telescopes. Its metallic lustre resembles neither of its con- stituents, and its tenacity is but about 20 per cent, of that of the weaker metal. Type metal, also, formed by alloying lead and antimony, in the proportions of four of the former and one of the latter, is a hard alloy, capable of being cast in moulds, taking form very perfectly, and it differs greatly in its properties from either lead or antimony. It is usually found that the temperature of fusion of an alloy is below, and often considerably below, that of either constituent metal. The strength of alloys is often greater than that of the metals composing them. The characteristics of the alloys will be discussed at greater length when treating of those compounds hereafter. The minimum percentage of metal in paying ores varies QUALITIES OF THE METALS AND THEIR ALLOYS. 41 with the value of the metal in the market, and the cost of reduction and transportation ; the following may be taken as fair averages : Iron 25 to 40 per cent. Lead 20 to 25 Zinc 201025 " Antimony 201025 " Copper 2 to 2.5 " Tin i to 1.5 *' Mercury I to 2.5 Silver 0.0005 to o.ooio per cent Platinum o.oooi to 0.0002 " Gold o.oooooi to o.ooooi " Where two metals exist together, as copper and silver, lead and silver, iron and manganese, the ore may be reduced for the one, and the other obtained incidentally, at less expense, when in even smaller quantities than above given. CHAPTER II. COPPER, TIN, ZINC, LEAD, ANTIMONY, BISMUTH, NICKEL, ALUMINIUM, ETC. 29. Copper (Latin Cuprum, Cu.) has been known to man- kind from some very early, and even prehistoric, period, and was applied in the manufacture of tools and useful implements, probably long before iron was used, or even known. It exists native and is comparatively easily reduced from its ores and worked, and hence could be obtained and worked at a time when the art of reducing the comparatively refractory ores of iron had not been acquired. Tubal Cain worked " in brass and in iron " ; the ancient Egyptians mined copper in the neighborhood of Sinai, and of it made an alloy which was used in making their mining and quarrying tools and are supposed by Wilkinson and other Egyptologists, to have been able to temper it as we temper steel. It is more likely, however, that they knew only how to produce and harden the alloys of copper and tin. All the more civilized nations succeeding those contempo- rary with Cheops used bronze extensively in making statuary and monuments, and the Greeks and Romans made a statuary bronze, taking a " patina" unexcelled in later times. Their foundry-work was fully equal to that of the moderns. It was also used in coinage by these nations as it is used to-day. The prehistoric nations of America used large quantities of copper, quarrying it in all those districts in the neighbor- hood of Lake Superior which have been recently worked for mass copper, and their tools are still occasionally found in the old workings. It was worked in Mexico by the Aztecs, and by the same race in Chili and Peru, before the discovery COPPER. 43 of those countries by the Spaniards. The bronze used by the Aztecs was of similar composition to that made by their Asiatic contemporaries, and that used frequently in modern times when a tough, as well as strong, bronze is desired 94 per cent, copper, 6 per cent. tin. Bronze implements of great age have been found in all parts of Europe, and so ex- tensively was it used in the period preceding that in which iron became common that that period has been denominated the " Bronze Age." According to Lubbock,* copper was mined in many locali- ties, and the knowledge of mining, alloying it and of casting in bronze was brought into Europe from the East. The tin with which it was alloyed was obtained, in the time of the Phoenicians, from Cornwall. The forms of the bronze im- plements found in Europe and in America are often strikingly similar. Bancroft f states that the American Indians were reported by Cabot, in 1598, to be familiar with this metal and its use. 30. Qualities. The metal has a deep red color, the only metal except titanium having that color, is heavy (S. G. 8.8 to 8.93) very malleable and ductile and has considerable tenacity. Its hardness is usually rated at 2.5 or 3. When warm, and when rubbed with the hand, it gives out a strong odor of a peculiar and somewhat disagreeable character. Commercial copper is contaminated with silver, lead, antimony and iron ; although the native copper, as much of that obtained from Lake Superior, is sometimes almost chemically pure. The melting point of copper is given by Pouillet as 2050 Fahr. (1121 C.) and vaporization occurs at the white heat, the vapors burning with the green flame which gives the characteristic lines of this metal in the spectroscope. It is a remarkably good conductor both of heat and electricity. Copper does not oxidize in dry air at ordinary temperatures, but does so rapidly in a moist or acid atmosphere, and at temperatures approaching the red heat. Of this metal from 125,0x30 to 150,000 tons are annually * " Prehistoric Times." f Vo1 - P- I2 ( Ed - l8 5 6 -) 44 MATERIALS OF ENGINEERING NON-FERROUS METALS. consumed, principally from the United States, Cornwall, Chili and Bolivia. It is supplied in the form of bars, wire, sheet and ingots, which latter are re-melted to obtain copper and alloys in castings. It is, next to iron, the most important and useful of the metals. Its valuable properties will be de- scribed at greater length, presently. 31. Copper Ores are distributed very widely over the earth's surface and are found in every large political division of the world. It exists in a great variety of forms, usually as sulphide or oxide; but in some cases, as in the United States, on the south shore of Lake Superior, is found in the form of native copper and in enormous quantities. Very large quan- tities are now mined in Montana, Arizona, and other western districts. Metallic copper occurs in masses, in flakes and sheets, in threads, and in spongy masses dissemimated through rock crevices, earthy gangue or even solid rock masses. Enor- mous blocks and extensive masses are found and worked in several of the mines of Lake Superior. These great blocks sometimes weigh several hundred tons. In this condition it is one of the most expensive ores of copper ; for the metal is excessively tough, and cannot be blasted, but must be pre- pared for the market by being cut up with tools ; and the presence of siliceous gangue in the mass renders this opera- tion very difficult. In the deposits worked in and near the Calumet and Hecla mine of that district, it exists in the red conglomerate in a peculiar form, permeating the rock very uniformly in just such a proportion as gives maximum ease and cheapness of mining and preparation. The metallurgists find that comparatively few of the cop- per minerals are of much importance, by far the largest pro- portion of this metal annually produced by the mines of the world being obtained from copper pyrites. Phillips gives the following list of the commercial ores of copper.* Native Copper is cubical, occurs crystallized in octahedrons, sometimes modified, lamellar, filiform, or arborescent, and has a specific gravity 8.83. No known locality produces such * Vide " Elements of Metallurgy ;" J. A. Phillips. Lond., 1874. COPPER large quantities as the region of Lake Superior, where it occurs in veins intersecting trap rocks, frequently associated with metallic silver. In small quantities, native copper is of fre- quent occurrence, but except in the region above mentioned, it is not of much importance as an ore. It is generally re- markable for great toughness. Cuprite (red oxide of copper) composition, Cu 2 O is cub- ical, generally in cubes and octahedrons, of a ruby-red color, with a specific gravity 6, and contains, when pure, 88.80 per cent, of copper. Melaconite (black oxide of copper) composition, CuO is cubical ; rarely found crystallized, but more commonly earthy ; is massive, or pulverulent, affording, when pure, 79.82 per cent, of copper. Malachite (green carbonate of copper) crystallizes in the oblique system, the crystals being often very complicated ; occurs more frequently massive or incrusting the surface, being botryoidal or stalactitic. The specific gravity = 3.7 to 4.1. Its composition is CuCO 3 , CuH 2 O 2 , yielding, when pure, 57.33 per cent, of copper. This mineral frequently occurs near the surface, in veins producing sulphides and other ores of copper, and has probably been derived therefrom by at- mospheric agencies. A2urttr(b\ue carbonate of copper) composition, 2CuCO 3 , CuH 2 O2 crystallizes according to the oblique system, and also occurs massive. Its specific gravity is 3.5 to 8.81 ; con- taining, when pure, 55.16 per cent, of metallic copper. It occurs largely in South Australia, and formerly at Chessy, near Lyons ; and is hence sometimes called Chessylite. Chalcopyrite (copper pyrites) composition, Cu 2 S, Fe 2 S 3 is prismatic, often in hemihedral forms, though more commonly massive, with specific gravity = 4.2 ; containing, when pure, 34.81 per cent, of copper. This, which is the most important ore, rarely contains, as sent to market, more than 12 per cent. of that metal, and frequently less. Bornite (purple copper ore) crystallizes in the cubical system, and has a specific gravity 4.4 to 5.5. Its composition varies, sometimes 3Cu 2 S, Fe 2 S 3 ; copper from 50 to 70 per cent. 46 MATERIALS OF ENGINEERING NON-FERROUS METALS. Chalcocite (gray sulphide of copper) is prismatic, and of specific gravity 5.7 ; its composition is Cu 2 S, yielding, when pure, 79.70 per cent, of copper. The copper sent into the market from the Lake Superior district is principally derived from crushed low-grade rock, containing native copper ; that coming from the southern Rocky Mountains is derived from oxides, and that from the Butte district of Montana and from Arizona is obtained from argentiferous ores. The copper smelted in the Appalachian sections is from pyritous ores. Altogether they yield between 80,000 and 90,000 tons annually. The output in 1845 was but loo tons,* that in 1891 was about 280 millions of pounds (nearly 175,000,000 kilogs.), valued at 12 cents per pound, or over $30,000,000, and was increasing at the rate of 10 to 15 per cent, annually. Much of this product is exported. The refining is done in works situated at Baltimore, Md., Orford, N. Y., and in various other scattered localities in the United States, as well as by the mining companies. The production of Great Britain is very small, and that of Spain and Chili is enormously great. Copper smelting in the United States is conducted, by three principal methods, according to the character of the ores. These are : f Fusion of native copper and refining; Fusion of carbonates and refining ; Reduction of sulphuretted ores and refining. Lake Superior copper is of the first class. It is melted down as received with its gangue and with 6 or 8 per cent, limestone and 10 per cent, refinery slags. The charges are about 12 tons each, which are worked in a large reverberatory furnace about 12 hours. The slags are skimmed and the richer grades are refined, while the remainder form a part of the next charge. The refining and ladling take 5 hours. Cupola furnaces are sometimes used, which take 20 tons at a run, of which 40 or 45 per cent, is limestone, 30 to 35 per * " Metallic Wealth of the U. S." : Whitney. | J. Douglas, Jr., in " Mineral Resources of the U. S." Gov't Print. (GeoL Survey ; Interior Dept.), Washington, D.C., 1883. REDUCTION OF COPPER ORES. 47 cent, anthracite coal and 4 per cent, copper. The lining fur- nishes a considerable amount of silica and is rapidly cut out. The Bessemer process is also used in reducing copper. 32, The Processes of Reduction of copper ores differ with their composition. The oxides and carbonates are easily re- duced, by fusion, in presence of carbon, with a siliceous flux. The copper is promptly reduced to the metallic state. Some loss is usually met with in consequence of the tendency of the oxide to form a silicate, and this is checked by supplying either an alkaline base, usually lime, or by mixing with sul- phuretted ores, of which the sulphur unites with the oxygen present and thus permits complete reduction. The sulphides are usually first roasted and thus converted to a considerable extent into oxide. This roasted ore is then smelted, sometimes in reverberatory and sometimes in blast furnaces, and this roasting and smelting is repeated until a " regulus " is obtained consisting of a nearly pure sulphide. This product is finally roasted with free access of air until, having been brought to a certain state, in which sulphide and oxide exist in the right proportion, a double decomposition occurs, yielding sulphurous acid and metallic copper (2CuS-f Cu 2 O = SO 2 + Cu c ) which latter is of fair degree of purity, and is known either as " coarse copper," or " blister copper," etc., etc. This is finally purified before it is sent into the market as ingot copper. The final process consists in melting down in the presence of an oxidizing flame and with fluxes, and, after removal of slag, " poling " or stirring with green birch rods or poles to produce thorough mixture and to decompose all oxide. Care and skill are required to prevent either " underpoling," which would leave oxide in the metal, or " overpoling," which reduces other metals and makes an alloy of reduced value. This last process of refining is the only one necessary in the treatment of the native copper of Lake Superior. 33. Details of Reduction of Copper Ores. In detail, these processes arc very complex, although sufficiently simple in their theory. The process of reduction usually practised consists of roasting to expel sulphur and arsenic, melting to 48 MATERIALS OF ENGINEERING-NON-FERROUS METALS. flux out iron oxide by siliceous fluxes, and roasting and smelt- ing in one operation to obtain the commercial metal. The first operation is that of breaking up the ore into small and, as nearly as may be, uniform pieces, removing useless gangue and assorting the ore in such a manner as to facilitate the processes of reduction. The next process is that of cal- cining, roasting, about three tons at a time, in a reverberatory furnace on a long and wide level hearth often 15 or 16 feet by 12 or 14(4.6 or 4.9 metres by 3.7 or 4.3) where it is spread in a thin layer and exposed to the action of the flame. The hearth is bricked over and cemented with fire-clay and the roof is a low arch. Openings from the fire-place admit the heating gases ; others from the atmosphere provide for oxida- tion by the admission of air ; and others at each side are arranged for the discharge of the roasted ore into a low arched space, or chamber, under the furnace. The ore is admitted through openings in the top surmounted by hop- pers, into which it is filled and left to heat gradually until dropped into the furnace. The fuel, a soft coal or a mixture of bituminous and semi- bituminous coal, is burned with restricted air-supply, and the resulting carbonic oxide passes into the furnace, where, meet- ing the required air, it burns to carbon dioxide, and the long flame sweeping over the hearth, heats the ore to the tempera- ture needed to roast it. While thus exposed to the heat of the burning gas, the ore is continually stirred and raked over to bring all parts of the charge into contact with the flame. During this process, any sulphur present is exposed to oxygen at high temperature, and a part, but never all, is oxidized, passing off as sulphurous acid ; or oxidizing in small amount still further, it unites with the copper to form a sul- phate. The arsenic passes off as white arsenic, arsenious acid, in the form of vapor. The copper also combines, to a slight extent, with oxygen, to form the suboxide of copper, and any salt of iron present in sulphides becomes changed to oxide. In some cases, the roasting is accomplished by indirect heating and out of contact with the flame from the grate, REDUCTION OF COPPER ORES. 49 and the vapors thus isolated are diverted for the purpose of converting the sulphurous acid into sulphuric acid, which latter is collected in the usual way in leaden chambers. Where the gases from the fuel mingle with the vapors of sulphur, and other products of roasting, they are often all carried into a " condenser," in which a spray of water is introduced to wash the air clean before discharging it into the atmosphere. The ore is now ready to be smelted. If any ores are to be treated which are free from arsenic and sulphur, they are not roasted, but are mixed with the other ores after the latter are calcined, and the mixture is then smelted. The smelting furnace, called often the " ore furnace," is a small reverberatory furnace, fitted with a comparatively large grate, and having a hearth so formed that the molten ore may lie on it in a shallow pool, deepest near the middle of one side of the furnace. The charge is about one and a half tons of ore, flux and slag derived from a later operation, of which the ore amounts to about two-thirds, while the flux and slags make up the other third. This being charged upon the bed of the furnace, the slag soon melts, and the whole charge later becomes molten and " boils " rapidly with disen- gagement of sulphurous acid. In the course of four hours, or less, the attendant uses his rubble, stirring the charge thoroughly, and at the same time raising the heat of the furnace until the coarse metal and slag separate. When this is done, the " matt " or " regulus " of partly refined or " coarse metal " is tapped off into a cast-iron box having a perforated bottom, through which it runs into a tank contain- ing water, and thus becomes granulated. The slag is run into moulds, and the blocks so formed of silicate of iron, principally are useful in building. The regulus is only one-third copper, the rest being sul- phur and iron, and the whole being a sulphide of copper and iron. It is charged again into the roasting furnace, and calcined for twenty-four hours, the workmen raking it over en or twelve times in the interval, as the sulphur burns out of the more exposed portions. The loss of about one-half the 50 MATERTAZS OF ENGINEERING NON-FERROUS METALS. sulphur reduces the charge to a mixture of iron oxide, copper sulphide, and some iron sulphide. This calcined regulus is then charged with slags from later processes in equal or greater quantity, and with any pure oxides or carbonates at hand, into a melting furnace, and there held in fusion about six hours, when the resulting regulus and slag are tapped off. The former may be run into water as before, and thus made " fine metal," or cast in pigs as " blue metal, 1 ' containing about seventy-five per cent, of copper. The best copper is found in the pigs last cast, the first producing a less pure metal called, later, " bottoms." or "tile copper." When less rich in copper, it is again cal- cined and melted to obtain block or coarse copper, contain- ing more metal. The slag, or " metal slag," as it is called, contains, usually, enough of copper to make it advisable to re-work it with the ores, as already described, or sepa- rately. Still another repetition of the calcining and melting proc- esses removes a part of the remaining sulphur, and yields what is called "blistered copper;" the "blisters" on the surface of the ingots giving evidence of the escape of sul- phurous acid while solidifying. Finally, this blistered copper is re-heated in charges of six or eight tons weight, with free access of air, and the arsenic and sulphur remaining are converted into arsenious and sulphur- ous acid, and the iron, lead, tin, and other oxidizable impuri- ties are converted into oxides before the charge is allowed to melt, this preliminary operation occupying about six hours. The metal is then melted down and sampled to determine how the process of " toughening " shall be con- ducted. This consists in " poling," or stirring the molten charge with poles, from young saplings of birch, usually, until sample ingots exhibit the density, toughness, fineness of grain, and pure copper color which indicate the desired quality. When right, or at " tough-pitch," it is run into ingot moulds and becomes " tough-cake." The process of poling results in the removal of the oxygen taken up by the copper in the earlier processes by contact with the hydro- REDUCTION OF COPPER ORES. 5 1 carbons and the pure carbon of the wood. Overpoling causes the absorption of carbon, and gives the same brittlencss which had been caused by oxygen ; and the avidity with which copper takes up both these elements makes this opera- tion one demanding great care and skill. Where sheet copper is to be made, lead is often added before casting, to give greater malleability, by fluxing out the tin and other alloy ; this lead is oxidized, and is all removed again with other oxides in the slag. Modifications of this process are adopted with leaner ores ; and the melting and poling only is necessary with pure native copper, such as is mined in the Lake Superior region in the United States. Copper is reduced at Ore Knob, N. C, from very pure but lean ores, containing from two to five per cent, copper. These ores are picked over carefully, and sent to the calcin- ing ground, where they are roasted in heaps, under sheds 240 to 300 feet long and 34 feet wide, the piles measuring 100 tons of fresh, or 50 tons of roasted ore. The roasted ore contains four to five per cent, copper. Fusion of the ores takes place in furnaces resembling cupolas, and the mattes are smelted in the same kind of fur- nace. The latter contain twenty or twenty-five per cent, copper. These " single mattes " are roasted in heaps, and fused in shaft-furnaces for black, or pig copper, and " double," or concentrated mattes. This black copper contains ninety to ninety-five per cent metallic copper, some iron, and other elements. The mattes are re-worked, and the crude copper is refined in reverberatory furnaces, taking five tons at a charge ; the product consists of 99.8 per cent, metallic copper. The wet processes of copper extraction are divided by Hunt * into three classes : I. Those in which the copper in sulphuretted ores is ren- dered soluble in water, after roasting them, converting them into chlorides or sulphates. II. Those in which free hydrochloric or sulphuric acid is * Trans. Am. Inst. Min. Engineers, vol. x., p. II. 52 MATERIALS OF ENGINEERING NON-FERROUS METALS. used to dissolve the metal from oxides or roasted ores. These are usually costly processes, and are seldom practised. III. A method by which a hot solution of ferrous chloride with common salt is used to convert copper oxides into chlo- rides. This is the Hunt and Douglas method. The Hunt and Douglas process of extracting copper from its ores consists, as practised in North Carolina and in Chili, in the dissolving of the oxides in a hot solution of proto- chloride of iron and common salt, thus converting the proto- chloride into peroxide of iron, and the oxide of copper into protochloride and dichloride, the latter of which is soluble in strong brine. From this solution the copper is precipitated by the introduction of scrap iron. This method involves almost no consumption of chemicals other than common salt, which is added to supply unavoidable losses. The sulphur- ous ores are converted into oxides by crushing, grinding, and calcination in three-hearthed reverberatory furnaces. The iron consumed amounts to seventy per cent, of the copper reduced as cement copper. One furnace roasts two and a half to three tons of ore per day, using one-third cord of wood. Special cases. Carbonate ores sometimes supply excel- lent copper, although rarely, if ever, equal to that found native. They are now smelted in cupola furnaces, in which the parts exposed to highest temperature are surrounded and cooled by water-jackets. These furnaces are capable of smelt- ing 50 tons per day. Oxides are similarly smelted, using about I ton of fuel (coke) for 6 or 7 tons of ore. The reduced copper is run into pigs or ingots of 250 to 300 pounds (115 to 160 kilogs., nearly) weight, and containing 2 or 2.5 per cent. slag. Sulphuretted ores are smelted both in reverberatory fur- naces and in cupolas. By the first method, the ores and slags, containing a mean of about 33 per cent, copper, are treated in charges of 4 tons each, and about four charges are worked in 24 hours. The matte is roasted and fused until a regulus is obtained containing 70 per cent, copper. This is slowly melted, the sulphur oxidized out of it, the slag skimmed and the charge oxidized sufficiently by the air- REDUCTION OF COPPER ORES. 53 blast to form oxide of copper and sulphurous acid and to produce the reactions, 2 CuO + CuS = 3Cu + SO, Cu+ SO. The gases thus carry some sulphuric acid. The metal should finally contain over 95, and even 98, per cent, copper. With labor at $2.25 and $1.50 per day and coal at $4.00 per ton, the cost of reduction is about $35 per ton of copper pro- duced. Cupolas and modifications of the broad-mouthed furnace of Rachette are also used for smelting the sulphuretted ores, and the cost is thus often reduced some 30 per cent. These furnaces are not as well adapted to treating a wide variety of ore as the reverberatory.* The latter is much better fitted than the former for smelting arsenical ores, and for use where wood is cheap, and charcoal, coal or coke expensive. The slag from the cupola is cleaner, the cost of repair may be made less, and no temporary loss of copper occurs as by its permeation of the bed of the reverberatory. When the ore is very lean, or contains elements difficult of removal by smelting, or when the separation of silver or other valuable metals alloying with copper is necessary, wet methods of reduction are practised. The copper is either separated by solution or by separate precipitation. Such processes are adopted to save the metal otherwise lost in mine waters either below ground or flowing from ore-heaps. Copper reduced by the dry method is liable to consider- able injury by absorption of oxygen while in fusion. The extent of this injury is well shown by the behavior of bars made for test by the author t in the course of investigations of the properties of bronze alloys. An analysis was made of the turnings of these bars for the purpose of learning whether the chemical composition would account for the presence of blow-holes and the lack of ductility. * " Mineral Resources of the United States." J. Douglas, Jr., p. 270. f Report of U. S. Board, vol. i. ; 1878. 54 MATERIALS OF ENGINEERING NON-FERROUS METALS. The result was the discovery of an extraordinary amount of suboxide of copper in bar No. I. This was no doubt caused by repeated meltings. The following are the analyses : NO. I. Per cent. NO. 30. Per cent. Metallic iron O.O2O O OIJ. 0.014 o 057 Metallic silver O O15 O OI4. none none none none Metallic tin none Metallic bismuth . . . none none Metallic lead trace trace Metallic copper . 87.000 06. ^qo 12.086 3. ego Carbon none 100.055 99-995 No. 30 had been less exposed to the air than No. I and less frequently remelted. 34. Metallic Copper, although both malleable and duc- tile, excels in the first quality and finds more frequent em- ployment in the form of sheet metal than in that of wire. These qualities are possessed in the highest degree by the pure metal and are greatly impaired by very slight admixture of foreign elements of metallic alloy. Its tenacity and hard- ness, although less than that of iron or steel, is greater than that of any other non-ferrous material ; and its power of resisting oxidation, of taking a fine polish and of easy work- ing, make it an extremely valuable material to the engineer. Good copper should have a strength of at least 30,000 pounds per square inch (2,109 kg- per sq. cm.) ; and cold-work- ing, by wire-drawing, for example, raises its tenacity some- times to double that amount. If worked hot in the presence of oxygen, it is liable to serious injury by internal oxidation, and, in presence of carbon, by the formation of the carbide. It becomes hard and brittle when hammered or wire-drawn, COPPER OF COMMERCE. 55 and its ductility is restored by annealing, by sudden cooling the opposite of the treatment required in annealing steel. It can be forged, when pure, either hot or cold, more easily than iron. It loses strength with increasing tempera- ture. Its oxide and carbonate are poisonous, and its surface is therefore tinned when it is used for culinary purposes or where liable to serious injury by corrosion. Copper is very seldom cast, unalloyed, in consequence of the difficulty of obtaining sound, strong castings. When fluxed with phosphorus, it is, however, possible to make castings of good quality ; and that metalloid is one of the best known fluxes for all its alloys. " Phosphorus-copper " has a strength, according to Abel, of from 30,000 to 50,000 pounds per square inch (2,103 to 3>5 X 5 kgs. per sq. cm.), as the per- centage of phosphorus added rises from one to three or four per cent. Riche* found that the density of copper, subjected alter- nately to mechanical action, then to tempering or annealing, displays inverse variations according as it is exposed to the air or sheltered from it during the re-heating ; while in the first case the mechanical action increases the density, in the second, mechanical action diminishes it. Professor Farmer has informed the author that he has succeeded in depositing copper, from cyanide solutions by electrolytic processes, harder than untempered steel. 35. Copper of Commerce. The copper found in the market is of several kinds, each known commercially by a different name. " Lake Copper " is that obtained in the neighborhood of Lake Superior, and is principally native copper. It is remark- ably pure, and when well handled in melting and poling, it is considered unexcelled for purposes as, for example, con- ductors of electricity, in which every trace of foreign matter reduces appreciably, and often seriously, the value of the copper. The best Lake copper has ninety-three per cent, of the conductivity of chemically pure copper. Australian, South American, and European coppers are * Comptes Rendus, vol. 55, 1862 ; pp. 143-7, 56 MATERIALS OF ENGINEERING NON-FERROUS METALS. usually not native coppers, nor are the coppers obtained from nearly every other part of the world. Japanese copper is a richly colored metal, which comes into the market in small ingots. All commercial coppers obtained from other than deposits of native copper are likely to be contaminated by the presence of arsenic, sulphur, oxygen, and alloyed with lead, tin, iron, nickel, bismuth, silver, and antimony, of which sulphur, oxygen, and antimony are most troublesome. Copper, as sold in the market, contains from one-tenth to one per cent, of foreign matter ; an excellent sample con- tained 99.9 per cent, copper. One-tenth of one per cent, of impurity, according to Egleston,'* may reduce the conduc- tivity of the metal ten per cent. The presence 'of one-half per cent, may make the metal worthless for many purposes. The following are analyses of three samples : f AMERICAN COPPER. EGLESTON. ORE KNOB. L. SUPERIOR. BALTIMORE. Metallic copper . . QQ. 80 QQ.83 QQ.6 1 ^ Oxygen O. 1Q o. 15 O.OO Sulphur O.OO O.OO O.OO Silver o.o^ 0.026 0.066 Lead O.OI 0.016 0.044 O.OO O.OO 0.088 Antimony O.OO O.OO o.o^c; Silver in 2,000 pounds 100.25 14. 6 IOO.O2 7 ' 3 99.893 IQ. 7^ A sample of Swiss copper, found by Berthier \ topossess extraordinary softness, ductility, and malleability, was com- posed of Copper 99 . 12 Potassium o. 38 Calcium 0.33 Iron 0.17 and that author concludes that its valuable properties are * Trans. Inst. Min. Engineers, vol. x., p. 63. t Ibid., p. 54. \ ' ' Essais par la Voie Seche. " COPPER OF COMMERCE. 57 due to the presence of the alkaline metals. Mallet proposes* to introduce an alloy of sodium and tin in the manufacture of gun-bronze to secure freedom from oxide, using 0.05 per cent, sodium, or less. Copper is too soft, and usually too weak, to be of as great value in the arts as iron, even were its price to admit of such use. It is principally employed in the form of sheets and wire. Copper in heavy sheets is sometimes used for the "fire-boxes" of locomotives, where iron would be rapidly corroded ; it is extensively used in making large vessels for manufacturers of chemicals and pipes. Copper pipes of large size, such as are used on marine engines for steam and feed pipes, are made by rolling up sheet copper and brazing the edges together. Small pipe is sometimes drawn to size in dies ; feed and " blow-off " pipes are usually thus made ; this " solid-drawn " pipe is more costly, but much better, than bra/ed pipe." The ductility, malleability, and the considerable strength of copper, permitting its being worked into rods, bars, wire, or sheets with equal facility, make it, next to iron, the most useful of the metals. Its quality is so greatly dependent upon its purity and freedom from oxidation or admixture with other metals, that it is very important to the engineer to see proper precaution observed in obtaining it for struct- ural purposes. Working by the hammer, in the rolls, or in the wire-mill, causes great increase in tenacity, while carelessness in melt- ing and casting it may render it worthless for the purposes of the engineer, and even the strengthening processes cannot be carried far except with occasional annealing. It may be worked either cold or hot, and forged like iron, if not so highly or so long heated as to cause serious oxidation. It oxidizes quickly at high temperatures, and also when exposed to a damp atmosphere. Fusing it under a layer of salt, it is less liable to injury in the foundry. Thin sheet copper is subject to a peculiar deterioration of strength, with time, which has been studied but little, and * " Construction of Artillery," p. 97. 58 MATERIALS OF ENGINEERING NON-FERROUS METALS. the cause of which is not fully ascertained. This degrada- tion of quality is singularly irregular and erratic, and affects the product of the best mills, as well as low grade copper. It has been noticed particularly in thin metal, as cartridge sheets. This metal is sometimes of nearly pure copper, but often of alloy with zinc in considerable amount. Cartridge metal, passing the severest tests, was reported by Capt. Michaelis as failing in firing ; later an improvement was observed. Dr. Egleston attributed failure in such cases to several causes, as impurities in the copper, oxidation, over- heating, underheating, and over-compression in the rolling mill. Large quantities of gas are sometimes separated from the metal, often many times its own bulk. The stress and flow caused by the presence of this gas may be the most usual cause of loss of strength with time. Copper is rarely worked in the lathe or by cutting tools ; it is soft, yet tough and tenacious, and is easily distorted by the resistance offered to the tool, which it clogs and causes, espe- cially if the latter is sharp and has an acute cutting angle, to chatter and dig into the work. Its peculiar qualities fit it well for working with the hammer, and it is often forged hot, and still oftener worked cold. Pieces are often cast and then hammered into the desired form, or beaten to the required degree of thinness. If, during the process, the metal becomes too hard and brittle, it is annealed by heating and suddenly cooling it. Joints are made either by " brazing " or " hard-soldering " with an alloy of copper rich in zinc, by rivetting, or by soft- soldering with an alloy of tin and lead. Copper vessels are usually brazed, and when used for culinary purposes, or when liable to be filled with alkalies or other substances which may dissolve the metal, are tinned. This operation consists in first thoroughly cleaning and brightening the surface by scraping or sand-papering, then washing with a solution of sal-ammoniac, or of zinc in hydro- chloric acid, which leaves a clean metallic surface, free from oxide and greasy matter. Tin is then melted in the vessel and rubbed over the whole interior, the surplus finally poured SHEET COPPER. 59 off, and the polishing completed. Oily and ammoniacal matters, and according to Sir Humphrey Davy, weak solu- tions of salt, attack copper, as do nearly all acids. 36. Sheet Copper was formerly much used by engravers, but has been much less generally called for by that trade since other engraving processes have been perfected. En- graved rolls for calico-printing often have their surfaces made of the finest sheet copper, but are sometimes made of the cast metal. Embossing cylinders are made of copper or gun- metal. The patterns are produced either by engraving or by stamping. Sheet copper is used to some extent, but less than for- merly, in lining air-pump cylinders for steam engines and pumps used in mines, where the water is found to seriously corrode iron ; but here, as in .sheathing ships, alloys with tin or zinc have displaced the unalloyed metal. The sheet copper found in the market is classed as Bra- zier's Sheets and Sheathing Copper. The sizes of the sheets are : SIZES AND WEIGHTS OF SHEET COPPER. BREADTH. LENGTH. WEIGHT. Brazier's 2 feet 4 feet. 5 to 25 Ibs. per sheet. Sheathing 2* " 3 " 4 14 inches. 5 " 5 " 6 " 48 inches. 9 to 150 " " 1610300 " " 16 to 300 " 14 to 34 oz. per sq. ft. The weight may be approximately computed by multiply- ing the cubic contents of the mass in inches by 0.32 12 to obtain the weight in pounds. The thickness of sheet copper is often measured by wire- gauge, and the diameter of copper wire is always so meas- ure d. Copper is used to some extent in electro-plating, and is of common use with a slight alloy of hardening metal in coinage ; sheet copper is often tinned. Nearly all the copper 60 MATERIALS OF ENGINEERING NON-FERROUS METALS. used in the arts, however, is alloyed with zinc and tin to form the brasses and bronzes. When used unalloyed, specifications should call for a tenacity of at least 25,000 pounds per square inch in castings, 35,000 in bars, and 60,000 in wire (5,075, 7,105, and 4,218 kgs. per sq. cm.). Copper wire is used in enormous quantities in the con- struction of electric and magnetic apparatus. Its great conductivity, which is six times that of iron, makes it pecu- liarly valuable for this purpose. Its greater conductivity for heat, also excelling iron two and a half times, has given it value for heating surfaces of steam boilers. Copper " fire- boxes " are often used in locomotives, and copper utensils are of frequent use in minor departments of engineering, as in distillation, and in chemical and culinary operations. It is used to some extent in the sheathing of wooden vessels ; but one of its alloys, a special sheathing metal, has now. nearly taken its place. The " fastenings " of wooden ships are, in the best practice, always made of copper; it oxidizes very slowly, and its oxide does not injure the timber through which it is driven. Its use unalloyed is far less extensive, however, than when alloyed with other metals. The steam and feed-water, and other pipes used on ship- board and on locomotives, are often made of copper, as are the staybolts of heating surfaces when the latter are made of this metal. Sheet copper is rolled, for fire-boxes and other purposes, up to 10 feet 10 inches (3.3 metres) long. These sheets must be free from cracks, blow-holes, or scale ; and to secure a good surface, the sheets are inspected while going though the rolling mill, and any defects detected are carefully removed by the chisel, or by scraping, before the finishing pass is given. It is even necessary, frequently, to plane the ingots before rolling them. Fire-box tube-sheets are hammer-hardened, in order that the " expander " used in setting the tubes may not distort the sheet. Hammer-hardened copper, when tested by ten- sion, stretches irregularly, and the hammer-hardened plate may thus be distinguished from plate not so treated ; the effect is COMMERCIAL COPPER. 6 1 also seen in the diminished elongation without much change of tenacity. Moderate hammering, according to Lebasteur, is quite as effective as more severe work. Copper rods, or bars, are made with the same care, and the same precautions are adopted, as in making sheet copper. If reduced by the wire-drawing process, the reduction must be small at each pass, and the metal should be occasionally annealed, if the reduction is considerable. The maximum reduction in diameter should not exceed -j^th inch (0.16 centi- metre). Rods intended for fire-box stays are often drilled through the axis of the stay, as a means of detecting fracture ; these stays are now sometimes made by rolling up heavy sheet copper on a mandril and then drawing to size. Copper tubes and pipe are sometimes made by repeatedly stamping disk-shaped ingots under the hydraulic press, and thus gradually changing their form to that desired. Very large quantities of copper are used in coinage. The consumption of copper in the United States is not far from 40,000 tons per annum, and a very nearly equal amount is used in Great Britain (2.8 Ibs. per capita). Copper is, when cast, rendered sound and strong by the use of phosphorus as a flux. Abel, in 1860, found that the introduction of 2 to 4 per cent.* produces a remarkably uniform, sound, dense and tough metal, exceeding the strength of ordinary gun bronze by one-half, and attaining a tenacity of 50,000 pounds per square inch (4,218 kilogs. per sq. cm.) Alloyed with tin to form bronze, and with zinc to make brass, copper has extensive use in all the constructive arts. It is used in alloying gold and silver for coinage, plate, and other similar purposes for which those metals are too soft. The copper usually amounts to about ten per cent, of the total weight. COPPER TELEGRAPH WIRE, as stated by Glover & Co., has weight and conductivity, if pure, as follows : * Construction of Artillery ; Inst. Civil Engineers, 1860. 62 MATERIALS CF ENGINEERING NON-FERROUS METALS. ON '0 'A\. 'a |ii ly S a O -M S H "S, aJr W I f | 8 8 8 | I | I M M M ft Ct CO *O v> hs OQ w C4 ir> OO M in H f^t^t^ frs, ON t^. rO H OO bsVO lO-^-^fON N M lO-^txO O "^C^H H OO-^-O lOH qn ?OIOHM looxiocfoo^ gjvo fOM trjiriw ^?WOO MOO-O"^? OOOOOOOOOOOOOO JNCO >ot-NONW row H omo"> ox oo cj oo NO 5 o oo oo o H H c) co W O\N N COM lOrovO ro^f*"> M* O\ coco ^^ "? H M f^^^oo HO o\ ^- vo rj. t^ oo o* el 10 fo oo r^. 10 6 \o* ONOO O -^rooo txO t^iOM coiooo woo ro oo ^-M O C7>r^.vo xo-^row ro CO 10 10 o -*^- -- O vo COPPER TELEGRAPH WIRE. 10 vo rs. oo ON -f r-> ro ^2 3 $ ? s <* o o o vS 5- 8 cf S" 2 . &8lfSEK <* ^*- M >o *]-( cioo tN. -^ M rx&oovo ^o^^ss-l g5&s < 8s > o* % 2v#ff:fo.?:;r t>. 10 O C7> O> N tx 00 * N IO N VO N O> O >O xo r * a iL a ji^s^ x w M w W f*^ ro (Y) \O M IO M M M n ft sS B. O^ m ro M 10 t* K* in vo 10 r^ M S ^ 2 $ S- S ^ tt \o* ^ *m <2 ? B 1 S O O O O 1 1 M v> vp r> n fO w C^ n ro M ttoo tooo roi-t o^tooo t^rof^ Sv-gS>U$8;Ev8^'S,P,?r Moovoio-^-mcsM OOOOOO O R S 5 S o o o M VI PI O fO & j j i i s & & ? ^ ? & OO ^^\O fOOf^^O^O *** Qiriw O^OC>^f^MOoK.iOOO w -^-00^ \O O^t^i- N 10 >O S3 fOlOlOOOVO ^T'T^ \o t^ PO oo oo t-^t^o^j^ *-oo N xoosO 10 ^" 1 1 c o % S -o- fe S of ^ I" O ts. ro 00 *fr M CO vo 10 ro wioRooobvoSo SKoN COOOvOt>.MM COtiOcOOO 9 iSfc M O\ PO O NO i ' -^- VO O & I 3. 2" R S M flt S> to co 10 m H 00 N 10 VO N A V? S % ^ CO vo v? xS *& & i I 1 1 ft ClooOO!5hvoiO MHIOO10( CO t^VO 100^--*f^ I f g i i g ?_l_?_ -_ -J_l_Ll ^ *2 S* ^ 2" 8 S S ^JT eT i? * J? ^ c?~ I 1 M I I j I 12 8 l-s I *l I a 2 S a 6 1 ll c -. u A U en 8-3 I! i ^1 fc J H en | 64 MATERIALS OF ENGINEERING NON-FERROUS METALS. 37. Tin (Si 'annum ; Sn.) is less widely and less plentifully distributed than copper, but has probably been as long known and as generally used. In fact, the two metals have always been, as they are to-day, almost invariably used together ; and their alloys, the bronzes, have been in general use since the earliest times. The ores of tin are found and worked extensively in Devonshire and Cornwall, Great Britain, and less extensively in Malacca, Banca, Germany, and Australia, in small quantities at Ashland, Alabama, and lately in the Black Hills of Dakota. Banca tin usually commands the highest price ; it is known in the market as " Straits Tin." Tin is found as u stream tin " (cassiterite) in many parts of the United States which are underlaid by the primitive rocks, and the ores are found in small quantities in California and other States west of the Mississippi, in Maine, and in Alabama. It is only worked at Ashland, and in a few other localities scattered over the United States. The tin used in the United States comes principally, via Great Britain, from Banca, Billiton, Cornwall, Australia, and South Amer- ica. The amount is above 10,000 tons annually. Tin sometimes occurs in the metallic state, but is gen- erally found as an oxide. 38. Ores, and Processes of Reduction. The common ore of tin, cassiterite, stannite, stannic oxide, Sn O 2 , is a dioxide, and is often called tin-stone or stream-tin. The ore usually contains between 65 and 75 per cent, metal. It occurs in veins traversing the primitive rocks. Much care is demanded in dressing it, and in assorting it into the four qualities usually classed at the mine. The ore is stamped, washed, weathered a few days, calcined, again weathered and washed, and finally smelted in reverberatory furnaces. The tin thus obtained requires refining, which is done as in the working of copper, the melting and poling demanding and occupying five or six hours, and yielding a very pure metal. The blast- furnace is sometimes used instead of the reverberatory, and is said to yield a purer tin. In detail, the processes of preparation are as follows : The oxide comes to the metallurgist as " tin-stone," or PRODUCTION OF TIN. 65 oxide, either as " stream tin ore," called often " alluvial ore," or " mine tin ore." The former is usually comparatively clean. The latter is washed, to free it from the earthy mat- ters accompanying it, by stirring it on a grating under a flowing stream ; it is then assorted carefully, the stony and useful part picked out and thrown away, the remainder broken, if in large pieces, and reduced to a sufficiently small size to work well under the stamps. The stamps consist of a series of heavy blocks of wood shod with cast iron, usually weighing 225 pounds (102 kilo- grammes) or more, mounted on the lower ends of vertical shafts. They are lifted by cams revolving on a horizontal shaft, which engage lugs secured to the vertical rods. The motive power is either water or steam, and the stamps make fifteen to twenty-five blows per minute. The stamps fall into a trough into which the ore is fed, and as it is pulverized by the blows it is washed out at the side, through a finely perforated screen, by a constantly flowing stream of water. From the stamps, the fine ore is carried by the current to a succession of settling tanks, in which it collects, while all other and lighter matter is swept away. The " slimes " thus retained are removed, are again washed in a flowing stream of water, and are then sent to the calcining furnaces. These are reverberatory furnaces, in which the sulphur and arsenic are driven out of the pyrites with which the ore is usually contaminated. The addition of common salt aids in this process, by the production of vaporous chlorides. The ore is now washed once more to remove the sulphate of copper which exists in the mass, and often still again to free it from oxide of iron and other lighter mineral matters, leaving the " black tin " in proper shape for smelting. The smelting process is conducted in reverberatory fur- naces similar in general form and method of working to those used in iron working. The charge of ore, now containing about sixty per cent, tin, and weighing a ton or more, includ- ing about twenty per cent, its weight of ground coal and lime, introduced as a flux to remove the silica, is dampened with a small quantity of water and spread upon the hearth. 5 66 MATERIALS OF ENGINEERING NON-FERROUS METALS. At a low, and long-continued heat, the oxide of tin gradually becomes deoxidized by the carbon present, and the metallic tin settles in the middle of the furnace, the hearth being slightly dished to receive and retain it. The ore is contin- ually stirred as this goes on, to facilitate the settling of the tin ; while the heat is finally considerably raised to produce a fluid slag. The slag is finally removed, and the tin is run off into a reservoir, from which, after the dross has risen to its surface and been skimmed off, the metal is cast in ingots. A portion of the slag is sufficiently rich in tin to be re-worked. The ingots of tin, made as above, are refined by re-melting and separation from the dross, and then " boiling" in a large refining basin, kept at a moderate temperature, somewhat above that of fusion, by a process resembling in principle the " poling" of copper. The wood is secured in the bottom of the tank under the tin, and the steam and gases rising from it as it chars beneath the molten tin, cause the foreign materials to separate and rise to the surface. This process being completed, the tin is again cast in ingots ; the quality of the metal being determined, not only by the extent to which the purification has been carried, but on the part of the pool from which the ingot is cast. The upper part is purer than the lower, and yields " refined tin," while the lower portion is ordinary " block tin " ; they should contain from 0.985 to 0.998 pure tin. The lowest part of the molten mass in the basin is reserved for further refining. A small blast-furnace is sometimes used, as in Saxony, in reducing the ore ; but it is a wasteful process. The fuel is charcoal, and the flux is either siliceous or calcareous, accord- ing as the ore contains an excess of basic or acid constit- uents. 39. Commercial tin is never pure. Chemically pure tin has a specific gravity of 7.28 to 7.4, according to the method of preparation, the purest being lightest. Its atomic weight is 116; color white, with a tinge of yellow; it possesses a peculiar odor; it oxidizes with difficulty, and when bent emits the crackling sound known as the " cry of tin." It has little tenacity, considerable ductility, and greater malleability. COMMERCIAL TIN. 6 7 The coefficient of expansion is 0.000023 ; its melting point is 443 Fahr. (232 Cent.) ; specific heat, 0.0562 ; latent heat of fusion, 14.25. It boils at a white heat ; its conductivity is low. Tin oxidizes very slowly in the air at ordinary tempera- tures, but burns quite freely at a white heat and with a white flame. Exposed to severe cold it becomes crystalline and friable. Its principal uses are in the making of alloys with copper, zinc, lead, etc., and in the manufacture of "tin-plate." The yellow oxide is used for polishing metals, such as steel cutlery and glass. The white oxide is used in making a white opaque glass generally known as " enamel." This metal is readily rolled into very thin sheets, known as tin-foil, and drawn into tubes and into fine wire. It resembles zinc in its change from great ductility at the boil- ing point of water, to equal brittleness at about 400 F. (204 C). It then melts a few degrees above the latter tem- perature, as already stated. The following is a complete analysis, made at the request of the Author, of Queensland tin : ANALYSIS OF "QUEENSLAND TIN. Per cent. I Lead o. 165 Iron 0.035 Manganese 0.006 Arsenic trace. Copper none. Zinc.. Per cent. Antimony none. Bismuth " Nickel " Cobalt " Tungsten " Molybdenum " Kerl * gives a set of analyses, thus : KIND. BANCA. BRITISH. PERUVIAN. SAXON. BOHEMIAN. Elements. . . . Tin I 99.961 o 019 0.014 0.006 2 99.9 0.2 I 99.96 2 98.64 I 93-50 O.O7 2.76 2 95-66 0.07 1-93 99.9 I 99-59 2 98.18 Iron . . Lead Copper 0.24 0.20 o. 16 0.406 "1.60 3-76 2-34 * Metalnuttenkunde, 1873. 68 MATERIALS OF ENGINEERING NON-FERROUS METALS. Grain tin is made by heating ingots to a temperature at which they become brittle and breaking them up by dropping them on the floor. MANUFACTURED TIN is found in the market in nearly every form in which iron and copper are sold. Tin-foil is made by rolling into plates and sheets, then heating, doubling, and again rolling, and repeating the latter processes until it is sufficiently thin for use as desired. It is sometimes rolled down in a compound sheet composed partly of lead ; and it is often alloyed with lead to make thin sheets and other forms. Tin-plate is made, as described in the preceding volume, by tinning sheet-iron, and consists prin- cipally of the latter metal. Copper, lead, and zinc are some- times tinned. Brass pins are tinned by dipping in a solution of the chloride or of the oxide ; the other metals are some- times similarly tinned. Unmanufactured tin comes into the market as " block tin," as " grain " tin, and in small bars or" sticks." Block tin is cast in ingots or blocks in moulds of marble ; grain tin is made by heating these ingots until very brittle, and then breaking them up on stone blocks ; it is sometimes granulated by melting and pouring into water. The production of tin has been enormously increased during late years by the increased demand for tin-plate, which is due to the growth of the " canning industries " and the roofing business. The consumption now exceeds a quarter of a million tons per year. Sheet tin, or tin-foil, is often no more than one-thousandth of an inch (0.00254 cm.) in thickness. The foil is used for wrapping tobacco and other materials which are to be pro- tected from the action of the atmosphere. Thicker sheets are used in " silvering " mirrors by amalgamation with mer- cury, and for making amalgam and for other purposes con- nected with the generation and use of electricity. Pure tin is used in making some tin vessels, as dyers' kettles. Its cleanliness and innocuous qualities make it valuable for tin- ning culinary utensils. The tubes are used sometimes alone, and often as a lining for lead pipe, in the supply of water to ZINC. 69 houses. The wire is very ductile and moderately tenacious, and has the perfect inelasticity exhibited by tin in all its forms. Tin is very extensively used alloyed with lead, in pewter and Britannia metal, and sometimes with a little copper as a hardening or "temper." The evidence lately discovered of the existence of an extensive region, bearing tin, in Dakota, according to the report of Professor Blake,* and of other deposits in Ala- bama, lead to the expectation of a large future development of this industry in the United States. Of the whole product of the world, over 15,000 tons per annum are used in Great Britain, probably nearly as much in the United States. Cornwall supplies above 10,000 tons per annum, Banca is producing large quantities, and Australia is rapidly approaching that district in its production. The use of tin for " tin-plates "sheet iron tinned on both sides is a very great proportion of the total. Good " tin-plate " is plated with the best tin, while the cheaper, or "terne," plates are plated with cheap alloy. Good tin-plate is distinguished by the thickness, evenness, and brightness of the coating of tin, the absence of dark spots produced by imperfections in the coating and of roughness due to the incomplete covering of the rough iron surface. " Pin-holes " in the coating often indicate a low grade of iron in the plated sheet. The iron should be good " charcoal iron," but in often " coke iron." The cheaper grades are as suitable for many purposes as the more expensive. 40. Zinc in the metallic state was not familiar to the ancients, although they were accustomed to use its ores in the manufacture of brass. The alloy was used in coins occa- sionally ; the Greek and Roman coinage was, however, prin- cipally bronze. Zinc was probably discovered, five hundred years ago, by Albertus Magnus, and by him called marchasita aurea ; its modern name was first given by Paracelsus in the middle of the sixteenth century. It became a regular article of manufacture about 1720, in Germany, and in England * Engineering and Mining Journal, 1883. 7O MATERIALS OF ENGINEERING NON-FERROUS METALS. fifteen or twenty years later ; the ore generally reduced was calamine, and the process was one of distillation. The metal had already been smelted in the East Indies. It has been regularly manufactured in the United States since about 1850, first at Bethlehem, N. J., and later in a number of other localities. The city of St. Louis, alone, supplies the market with fifteen tons per day. The whole product for the United States was, in 1888, about 60,000 tons (or tonnes, nearly). Zinc ores were known to the ancients, and were used in the manufacture of brass long before the art of reducing them was discovered. The alloy was made by smelting together the ores of copper and zinc. The metal became known about 1600, but was little noticed until after Hobson and Sylvester discovered, in 1805, that it becomes ductile and malleable at about 300 F. (144 C.), when it was brought into the market in competition with lead. It has since been extensively used for sheathings, roofing, culinary, and other vessels, architectural ornaments, etc. The oxide is exten- sively used as a substitute for white lead. 41. Ores of Zinc occur abundantly in the United States, the best being obtained in New Jersey, Pennsylvania, and Virginia, and in a line of deposits running through West Virginia and the Middle States, across to Illinois, Missouri, and Kansas, and north into Wisconsin. Large quantities are mined in Missouri and other parts of the country. They are mined extensively in Europe. Calamine and blende are the ores principally used in the production of the zinc of com- merce. These ores are the carbonate known as calamine, the sili- cate, or siliceous calamine, the sulphide, or blende, and the oxide, or red ore. The latter is given its color by the oxides of manganese and iron which are present with the zinc. It is the common ore of New Jersey. Calamine is also found in the United States, near the red ore. It is a common ore in the North of England and in Scotland, in Belgium, Silesia, Spain, and Sardinia. It is an impure carbonate, having a peculiar columnar structure, a dirty red color, and moderate cohesion. OKES OF ZINC. 71 It often contains lead, iron, manganese, and cadmium and rarer metals. When raised from the mine, the ores are carefully picked over, and the gangue and lean ores removed as completely as possible. They are next broken to small fragments or powder under stamps, and washed very thoroughly. They are calcined and smelted, the calcination rendering them porous and more easily reducible by driving out moist- ure and carbonic acid. The process is generally conducted in reverberatory furnaces, but sometimes in kilns. In smelting, the ore is mixed with half its weight of any cheap form of carbon, the two materials being well ground and mixed, and is reduced at a high temperature in retorts or muffles, usually three feet long and eighteen inches high, a half-dozen being heated in a single furnace. The reduced metal passes off in the state of vapor, condenses as it issues through a properly formed channel, and flows into the moulds placed to receive, it. The process is therefore one of distilla- tion. Two processes are in use the Belgian and the Silesian. In the former the distillation is carried on in cylindrical retorts, four or five diameters in length, put up in " benches," which consist of forty or fifty, or even more, set in several rows, one above another, within a furnace stack, with one end depressed and accessible from the front. Two or four furnaces are often built in one structure, and their products of combustion are led to a single chimney. The upper rows of retorts are charged with about sixteen pounds (7.26 kilo- grammes), and the lower with fifty per cent, more ore, the charge being first moistened to prevent the formation of dust. The furnaces and retorts are heated separately, and after three or four days' heating the former, the latter are intro- duced. The open end of the retort is closed by a fire-clay plug to which an iron funnel-shaped cap is fitted to conduct the distilled zinc away, while acting also as a condenser. Every two hours these are removed and cleared out, the zinc collected in them thrown into a ladle, and the unreduced oxide found with it is re-worked later. The retorts are re- 72 MATERIALS OF ENGINEERING NON-FERROUS METALS. charged every twelve hours, and the furnaces are only stopped for repairs about once in every two months. The zinc is poured from the ladle, when filled, into ingot moulds. In the Silesian process, the distillation is carried on in ovens or muffles, which are better calculated to bear high temperatures, and in which, therefore, the work can be more perfectly done. The distilled zinc runs down an iron tube, which is the condenser, into a small reservoir at the mouth of the oven. Thirty-two are set in- a furnace. They are re-charged once a day. Re-melting is carried on in clay-lined iron crucibles or kettles. The fuel consumed in these processes is from about six times the weight of ore in the best examples of Belgian work, to twelve or fifteen in the Silesian furnaces. Zinc ores are often found to contain lead, and their treat- ment by usual processes is somewhat difficult. Thus Chen- hall * gives : COMPOSITION OF ZINC ORES. CONSTANTINE. CAVALO. BLUESTONE. AMERICAN. :Zinc IO.64. IT 4.O 2Q 28 27 2O Lead 4.8l 17. 14 I2.QO 12 OO Copper . 1 . 3^ O 44. O 6^ O 2O Silver and Gold . . o 04. o 06 O O^ Sulphur 26.85 je . -27 22. 14 Iron . ... IQ Q^ 4. 08 7 16 Alumina 2. -l-l I O2 Magnesia O.22 Barium sulphate Silica 26.4.8 35-04 1 1 . IQ 26.84 Arsenic. o 65 OTT O I ^ Lime o 60 0.84 Sulphuric Acid 7 . C.T. Antimony o 02 Oxygen and loss 2-77 I. 01 I. 01 IOO.OO IOO.OO IOO.OO These ores are treated by the Parnell process of dissolving in sulphuric acid, and decomposing the sulphate by heating Proc. British Institute Civil Engineers ; 1882-3 I Part iv. METALLIC ZINC. 73 it with the sulphide. The loss is reported to be, for lead ores, which are similarly treated, three per cent. Commercial zinc thus prepared usually contains some lead, and may contain a considerable amount. Where needed pure, it should be very carefully selected by analysis. 42. Metallic Zinc is a bluish white metal known to the trade as " spelter" Its atomic weight is 65. It is rather brittle, and can be rolled satisfactorily only when heated somewhat above the boiling point of water. When pure, it can be worked, with care, into bars or sheets at ordinary temperatures. After passing the boiling-point, it again gradually loses its ductility and malleability, and can be powdered readily at a tempera- ture somewhat below the red heat. The rolling of this metal was at first accomplished with very great difficulty, from the fact that its malleability is confined to very narrow limits of temperature. For this reason it is always an operation only entrusted to experienced hands. The most suitable temperature is about 120 Cent. (248 Fahr.), and this must be maintained throughout the process. Below this point the metal opposes too great a resistance, and must be re-heated; above this point it be- comes brittle ; at 200 Cent. (390 Fahr.), it can be brayed in a mortar. Zinc should be re-melted before being rolled into sheets. The heat of fusion varies between 400 Cent, and 50x3 Cent. (750 Fahr. and 930 Fahr.). Re-melting is generally per- formed in a reverberatory furnace to cleanse the zinc of im- purities. The thickness of the ingots must vary with the final dimensions required ; this renders re-melting indispens- able. The re-melted plates are first roughed down or rolled between heavy rolls, and after being cut down to a fixed weight, are taken to the finishing train, where the rolling is completed. There are thus two distinct operations the roughing down and the finishing. Between the two, the sheets are re-heated in annealing boxes placed upon the melting furnace. Each operation gives rise to a production 74 MATERIALS OF ENGINEERING NON-FERROUS METALS. of scrap, which is more or less large in amount according to the quality of the metal and thickness of the sheet. This scrap, and all defective sheets, are re-melted with the ingots from the foundry. The fact that zinc, heated to a temperature exceeding the boiling point of water, becomes malleable, was discovered about the year 1805, and rolled sheet zinc then soon made its appearance in the market, and was used to some extent as a roofing material. Zinc is used extensively in the form of sheets for roofing, sheathing of iron ships, domestic utensils, etc., etc. Very large quantities are used by the engineer in the brass alloys and in the surface-protection of sheet-iron. It unites readily with the other useful metals to form alloys, which are usually characteristically different from their constituents. The prin- cipal of these alloys are the brasses, or alloys with copper. The metal is also often mixed in small proportions with the bronzes, or copper-tin alloys, to form the copper-tin-zinc ter- nary alloys often used in machine construction. Of the world's product of this metal, amounting to above 200,000 tons, the United States produces twenty per cent. Belgium and Germany make two-thirds. Zinc sheets of standard dimensions have the following weights : THICKNESS AND WEIGHT PER SQUARE FOOT. Inch. .0311 = 10 oz. .0457 = 12 OZ. Inch. .0534= I40Z. .0611 = 16 oz. Inch. .0686 = 18 oz. .0761 = 20 oz. Cast zinc, as well as rolled, is often used in the manufac- ture of ornamental work ; it takes the impression of the mould as sharply as good foundry iron, and is especially liked for small work. A prize offered in 1826 by the Society for Advancement of Industry in Prussia, led to the discovery, by Krieger, of Berlin, that hollow ware can be cast in zinc, and, by Geiss, that it would make good architectural ornaments. An exten* METALLIC ZIXC. sive consumption of the metal for these purposes at once arose, and the applications of zinc in these directions are becoming rapidly more general. It is largely used in decora- tion, as a substitute for bronze, and to a considerable extent in the construction of large statuary ; in this case, however, the mass is usually built up of smaller parts soldered together. Berlin has been the head-quarters of this industry. Zinc castings made at a high temperature are brittle and crystalline ; when cast at near the melting point, they are comparatively malleable. It is hardened by working, and must be occasionally annealed. The value for sheathing and for work exposed to the weather, arises from the permanence and impenetrability of the coating which forms over its surface a basic carbonate. Zinc is the most strongly electro-positive of the metals of commerce, and is almost exclusively used as the perishable element in voltaic batteries. It has a specific gravity of 6.9 to 7.2, melts at 770 F. (410 Cent.), and boils at 1900 F. (1040 Cent.) ; its vapor burns readily with a bluish-white flame, forming the white oxide. The salts and the higher oxide of zinc are extensively used in the arts, especially in making paints and dyes. The chloride is used in large quantities as a preservative of timber and as a disinfectant. Rolled zinc is made very much as sheet lead or sheet copper is made ; but its temperature must be kept at a little above the boiling point of water, to secure the necessary malleability, and it must also be free from alloy. It is freed from its most usual constituent, lead, by re-melting the spel- ter, as received from the furnace, on the hearth of a rever- beratory furnace which has a gradual slope terminated by a basin, into which the melted metal flows, and in which the zinc and lead separate, the lead settling to the bottom, while the zinc lies on the top. The zinc is ladled out and cast into ingots for the mill. These ingots are warmed to the proper temperature, and then rolled into sheets, and sometimes into bars, between 76 MATERIALS OF ENGINEERING NON-FERROUS METALS. rolls kept heated by the passage through them of steam of moderate pressure. Galvanized iron is sheet iron covered with a coating of zinc by immersion in molten zinc. Zinc is produced in the United States to the amount, annually, of about 60,000 tons (1888), and the production is rapidly increasing. At least one-half comes from Illinois, one-third from Missouri, and nearly as much from Kansas. New Jersey supplies zinc of excellent quality, and furnishes all that is exported, sending abroad over 40,000 tons of ore. The gas-furnace of Siemens is now adapted to smelting zinc, and is coming into general use in consequence of its cheap- ness of operation and manageability. The known deposits of zinc are being rapidly worked out. The importations of foreign zinc into the United States are more than equalled by the export of special grades of American zinc to Europe, where the metal is much sought on account of its high value for the manufacture of military rifle cartridge cases. The amount of coal used for one pound of zinc is the fol- lowing at the different works, the Eastern works using anthra- cite principally, and the Western works using bituminous coal : FUEL. REDUCTION. TOTAL. Passaic . .. . 4. ? I 3 5 8 Bergen Point e . c I Q 7.4. Lehigrh 4c I 7 6 2 Carondelet 4.4 I 2 5 6 The yield of zinc is stated to be Lehigh, for calamine 73 . 5 per cent. Lehigh, for blende 70 . o " Passaic, for calamine 80 . o " Martindale, for blende and silicates 73 -O " Carondelet, for silicates 76. So " Of the whole quantity consumed in the United States in 1883, about ten per cent, is used in galvanizing wire. LEAD. 77 43. Lead (Plumbum ; Pb.) is a bluish-white, lustrous, in- elastic metal, so soft that it may be easily scratched with the finger-nail. It has too little tenacity to be readily drawn into fine wire, although some lead wire is found in the market. It is very malleable, and is very extensively used in the forms of sheet-lead and lead-pipe. It is very heavy (S. G. 11.4), and is easily fusible, melting at 620 F. (327 C.) ; it absorbs, in fusing, 5.4 metric thermal units per kilogramme (9.8 B. T. U.). Its specific heat is 0.03 at low temperature, and 0.04 near the melting point. The coefficient of expansion is given by Calvert and Johnson at 0.00003. It is a very bad conduc- tor of both heat and electricity. At high temperatures it becomes slightly volatile ; in this respect and in changing in character from ductile to brittle as the melting point is approached, it resembles zinc somewhat. Oxidation occurs but slowly in dry air, and the oxide forms a protecting coating over the metal. When exposed to moist air containing carbonic or acetic acid, however, oxidation progresses rapidly. Lead is readily dissolved in water containing carbonic acid or salts of nitric acid ; the solution is poisonous, as all the salts of lead are cumulatively poisonous. Lead oxides are of great value in the arts. " Red lead," or minium (Pb 4 O 5 ), is used, mixed with drying oils, as a pig- ment, and by the engineer as a cement, in the latter case often mixed with " white lead," a basic carbonate [2PbCO 3 Pb (OH) 2 ], which admixture gives greater hardening and cement- ing power; this quality is often still further improved by the addition to the cement of red and white lead, in oil, in equal parts, of several times its weight of borings of iron with a little sal-ammoniac and sulphur. Red lead is much used in the manufacture of flint glass. Lead compounds are easily identified by the formation of the yellow oxide in the reducing flame of the blow-pipe. Lead salts in solution give a black precipitate when exposed to the action of sulphuretted hydrogen. Lead was known, but was of little importance in the earliest historic times. It is supposed to have been discov- 78 MATERIALS OF ENGINEERING NON-FERROUS METALS. ered later than either copper or tin. It was the custom, apparently, among the Hebrews and their contemporaries, to engrave records of importance, and which were desired to be made permanent, upon tablets of lead with an iron stylus. The Phoenicians used the metal in weighting anchors, and sold it to the Greeks and the Egyptians. It was used by the Babylonians, according to Herodotus, in securing iron cramps in masonry, probably in the same manner as is usual in modern engineering. 44. The Ores of Lead are galena or the sulphide, and the carbonate. Nearly all the lead of commerce is obtained from galena, which consists of eighty-seven per cent, lead, nearly, when pure, and 13 per cent, sulphur; it nearly always contains silver, sometimes in quite large amounts, varying from a fraction of one per cent, up to fifty per cent. ; arsenic, copper, iron, and zinc. The ore is very often worked for its silver. Galena is worked in Saxony and Bohemia, in Eng- land, Spain, and the United States ; it is usually found in the palaeozoic rocks. The ores worked in the United States generally contain comparatively little silver, and are quite pure. They are found principally in the valley of the Mis- sissippi. Enormous deposits exist in Missouri, Iowa, Illinois, and Wisconsin, in crevices and pockets in those lower Silu- rian rocks which have lately been distinctively known as the galena limestone. These deposits have been worked only from about 1820, although the existence of the ores had been then known more than a century. The ores of lead occur all through the Alleghanian districts of the eastern United States, but none are profitably worked. Lead ores are now often smelted in furnaces of the Rachette type, i.e., having a rectangular form and widening section from bottom to top. These permit the use of a low pressure of blast, and comparatively unlimited magnitude of charge. The fuel is usually charcoal or coke, or both, the flux is iron and limestone, or sometimes silica, and the ore is broken to the size of the fist or of an egg. The ore is often first roasted. The total fuel used amounts to from fifteen to twenty-five per cent, of weight of charge. THE SMELTING OF GALENA. 79 45. The Smelting of Galena is performed in a rever- beratory furnace, first roasting it, usually adding a little lime, until it is largely converted into lead sulphate. An increase of temperature of furnace with an oxidizing flame drives off the sulphur in the form of sulphurous acid, and the reduced metal is tapped off. Some of the lead is volatilized, and is condensed in the flues or in a vacuum chamber, constructed for the purpose, in which it meets with a shower of water. Antimony and tin, when present in objectionable propor- tions, are oxidized by exposing the molten lead, in shallow pans, to the action of the air. Silver is removed, often, by the Pattinson process of concentration, by melting, agitation, and slow cooling, with repeated separation of the crystalliz- ing metal which contains little silver, from the more infusible portion which is richer in the precious metal. The final product is subjected to the action of the air at high tempera- ture, which oxidizes the lead and leaves the silver in the metallic state. The lead-smelting process is very largely, like the process of reducing copper, one of desulphurization. The prelimi- nary roasting of galena converts a part into oxide of lead, the metalloid passing off in sulphurous acid, while another por- tion becomes a sulphate. The whole mass is then melted, the sulphur all passing off in sulphurous acid, and the metallic lead is left behind. This is done on the basin-shaped hearth of a reverberatory furnace, which is about six feet (1.8 metres) wide and 8 feet (2.44 metres) long, and is lined with slags melted down in place. The tap-hole for the slag is above that for metal. The process of smelting is conducted in four operations or " fires." The lead tapped off at the first melting of argentiferous ores is richest in silver. As soon as it is out of the furnace a second charge is thrown in and roasted ; the dross from the preceding charge is added. Some lead is reduced and is tapped off after an hour or more, and the remaining ore is, in the course of about two hours, converted into oxide and sulphate. The temperature of the furnace has been, up to this 80 MATERIALS OF ENGINEERING NON-FERROUS METALS. period, kept below the red heat, in order that the ore may not melt down and the desired change thus be checked. The heat is now increased to a full red, and the reaction of the oxide and sulphates present upon the sulphide, leads to the reduction of the lead, which runs off freely. This process occupies about an hour, and the temperature of the furnace has been alternately raised and depressed to facilitate the separation of the metal ; a little lime being added, also, to flux the ore. The temperature is now again raised for another hour ; more lime is added, and further reduction occurs. Finally, the furnace is heated to its maximum temperature, and held at this heat for three-quarters of an hour or more, when the lead is tapped off, the slags hardened with lime, and reduc- tion is complete. The whole process has occupied five hours or more. The fuel consumed amounts to something more than one-half the weight of the ore smelted. The slag is still rich in lead, and is again worked separately. The molten lead tapped off is often refined, as is done in purifying tin, by the use of sticks of wood in the basin. It contains a considerable amount, often, of silver, copper, anti- mony, and iron, amounting sometimes to several per cent. This is partly removed by the process of " softening," which consists in running it into a reverberatory furnace, having for its hearth a shallow basin, and there oxidizing out the im- purities by exposing it to the oxygen-laden gases passing over it. The process of smelting has of late been modified, and is now very generally conducted in blast-furnaces, instead of in reverberatory furnaces. When rich in silver, Pattinson's process is adopted. This consists in melting in a series of basins, in which the metals gradually separate. Lead crystallizes at a lower temperature than the alloy, and the molten metal being allowed to cool slowly, crystals of comparatively pure lead are formed, which are separated from the remaining mass which is richer in silver, and are transferred from one melting pot in a series to another; the lead richer in silver being gradually separated until that to be sent to market contains little to pay for COMMERCIAL LEAD. 8 1 further working. The melting pots are set side by side, and the purer lead is transferred from pot to pot in one direction, while that containing silver is similarly transferred in the reverse direction, until the pots at the extremes of the series contain, the one nearly pure and marketable lead, while the other contains so much silver that it can profitably be worked to recover it. This method is going out of use. 46. Commercial Lead. The lead is run into "pigs" about 3 feet (0.9 metre) long, usually weighing about 150 pounds (70 kilogs.). Spanish "pigs" weigh 112 pounds (50 kilogs.). A " fodder" is 8 pigs. Pig-lead is rolled into sheets 6^ to 7% feet (2 to 2j/( metres) wide, 30 to 35 feet (9 to 1 1 metres) long, and sent to market in rolls. The weight runs very nearly six pounds per square foot for each o.i inch thickness (120 kilograms per square metre per centimetre in thickness). Sheet-lead is extensively used for tanks, sheathing % etc., and sometimes, although less than formerly, for roofing. Lead-pipe is made as below by forcing lead through an orifice, the size of the pipe to be made, over a former which gives it the required internal diameter. Lead shot is made by dropping the molten metal from the top of a shot-tower of such height that the globules of the leaden rain thus produced may cool and become solid before striking the water in a tank at the bottom, placed there to receive it. Lead pipe is now made by a peculiar process called " squirting" ; it was formerly made by a process of " draw- ing" through dies. In the modern process, the lead is melted in crucible, or iron pots, and then carried to a com- pressing chamber fitted with a plunger which is driven by hydraulic pressure. The lead is allowed to solidify and cool to about 400 F. (204 C.). The ram is then forced down upon it, and, at a pressure of a ton and a half or more per square inch, the lead flows freely from an orifice in the bottom of the chamber, and around an iron core attached to the plunger, thus taking the size desired, and issues in the form of a pipe of a length determined by the relative capacity of the chamber and section of pipe. 6 82 MATERIALS OF ENGINEERINGNON-FERROUS METALS. Bar lead and lead wire and rods are made in the same manner, but dispensing with the core on the plunger. The compressing chamber is sometimes attached to the hydraulic press plunger, and rises against a fixed plunger in which is the orifice of issue, while the core is fixed in the compressing chamber. This arrangement is more convenient and causes less frictional resistance. Tin-lined pipe is often made. The alloys of lead will be referred to later. The oxides and salts have great value in the arts. White lead, the carbonate of lead, is made by exposing sheet-lead to carbonic acid and moisture. The lead is coiled up in pots, piled in heaps and covered with spent tan-bark and horse-dung. A little acetic acid, in each pot, attacks the metal, forming the acetate, which is then altered into carbonate by the carbonic acid generated in the hot-bed. It it used extensively in making paints. Red lead is produced by heating the protoxide in the presence of oxygen and thus converting it into the peroxide. Litharge is made by similarly acting upon the metallic lead and thus forming the protoxide. It is used as flux, as a constituent of cement and in the manufacture of red lead and of glass. The salts of lead are much used in medicine and to a con- siderable extent in dyeing. They are all poisonous. Lead is now produced in the United States at the rate (1884) of about 150,000 tons annually, and the production is increasing at the rate of ten per cent, or more a year. But little is imported. Of that produced in the United States, Utah yields about 20 per cent., Nevada, 6 to 8 per cent,, Colorado, over one-third, principally from Leadville, and Missouri and Kansas 15 per cent. Great Britain produces very nearly as much as the United States, reducing Spanish and other imported ores, which are principally argentiferous. Spain exported nearly as much more, and Germany quite as much. 47. Antimony (Stibium; .), is a grayish white, crystal- line and lustrous metal, moderately hard, extremely brittle, of inferior tenacity and has a peculiar taste and odor. It ANTIMONY ; BISMUTH. 83 melts at a low red heat, 840 F. (450 C), and may be dis- tilled at a white heat in an atmosphere free from oxygen. It does not oxidize in dry air at ordinary temperatures, but takes up oxygen slowly in cool, moist air, and rapidly when hot. It expands while solidifying, like iron. Its specific gravity is 6.7. The most common ore is the sulphuret, which is found abundantly in Borneo and in considerable deposits in Eng- land, France, and Hungary, and also in California. It is reduced by roasting to expel the sulphur. The salts of antimony are poisonous. The metal is a bad conductor of heat and electricity, and is used, with bismuth, is making thermo-electric piles. Its principal use is in the manufacture of alloys, as britannia metal, type metal, pewter, specula, etc. It expands when solidifying from fusion. It is rarely used alone. Antimony is found in abundance in the Rocky Mountain section of North America, and especially in California and Nevada. The ore is usually a crude sulphuret, containing, often, some bismuth and a little silver. It is smelted at several points and sold in the eastern markets for use in making type metal, britannia ware, and babbitt metal. Gray antimony was used by the ancients for coloring the hair and eyebrows. 48. Bismuth (Bi. ; atomic weight, 208) is a brittle, pink- ish white, heavy, useful metal, having some resemblance to antimony. It has a specific gravity of 9.8 to 9.9. It expands on solidifying, at a temperature of 500 F. (260 C.). Its co- efficient of expansion is 0.00134; specific heat, 0.0305. It crystallizes with remarkable facility. It may be distilled at a high temperature. It is very diamagnetic. Its principal use is in making alloys. The metal is obtained either by reducing the sulphide or, oftener, by purifying native bismuth. Its oxides and salts are used in medicine, and in the arts to a moderate extent, only, almost invariably alloyed with other metals. Commercial bismuth contains many impurities, which are 84 MATERIALS OF ENGINEERING NON-FERROUS METALS. removed by fusion with nitre. Chemically pure bismuth is obtained by precipitation, by dilution of its solution in nitric acid. The bismuth of commerce comes principally from Germany and Bohemia, and some from Peru. Deposits of oxides and sulphides have been found in Utah.* The quantity mined is not great and the demand is small, not more than ten or fifteen tons being used in this country annually. It has about one-eighth or one-tenth the value of silver. 49. Nickel (NL; atomic weight, 58.8) is a bluish, nearly silver white metal, having high lustre, considerable ductility and malleability, and closely related, chemically, to iron and cobalt, which metals are often associated with it, in nature. It has about the hardness of iron, but is heavier, having a specific gravity of 8.3 to 8.9, has about equal fusibility, but is far less subject to oxidation and corrosion. Its oxide is white and defaces the polished metal comparatively little, and is easily removed. Nickel can be either cast or forged; but it is generally used in making alloys or in plating more oxidizable metals. It is magnetic, although much less so than iron. The Ores of Nickel are the arsenide, which is by far the most common, and is known to the miners as kupfernickel, the sulphide, the sulphate, and the silicate. Nickel ores are found in France, Sweden, Cornwall, Spain, Germany, New Caledonia, and in Oregon and other localities in the United States, Pennsylvania supplying the greatest quantity. The ores are reduced by fluxing with chalk and fluor-spar, if arseniated, or by roasting and then reducing with charcoal and sulphur to the state of sulphide, and then by double decomposition with carbonate of soda, obtaining the car- bonate, which is finally reduced with charcoal. The metal was discovered and the ore reduced as early as 1751 by Cron- stadt. The nickel ores of Oregon have the following composition as given by Hood, as determined by analyses of ores sent to San Francisco : * Polytechnic Review, April, 1876. NICKEL. A. B. GARNIERITE. NOUMEITE. Silica 48.21 4.0. is 4.7 21 4.7 QO Iron and alumina oxide. . . . Nickel oxide 1.38 21.88 i-33 2Q 66 1.66 24 OI 3.00 24 OO IQ.QO 2 1. 7O 21 66 12 51 Water 6 61 7.OO 5oc 12 71 A. Amorphous. Hardness, 2.5 ; specific gravity, 2.45 ; color, pale apple green, becoming lighter by exposure. Ad- heres to tongue ; not unctuous. Does not fall to pieces in water. B. Amorphous. Hardness, 2.0-2.5 ; specific gravity, 2.20 ; color, dark apple green, becoming lighter by exposure. Ad- heres to tongue ; unctuous. Falls to pieces in water. Gamier it e. Amorphous. Hardness, 2.0-2.5 ; specific gravity, 2.27 ; color, apple green. Adheres to tongue ; not unctuous. Falls to pieces in water. Noumeite. Amorphous. Hardness, 2.5 ; specific gravity, 2.58; color, dark apple green. Does not adhere to tongue; unctuous. Does not fall to pieces in water. NICKEL ORE A. This mineral is amorphous, and much broken up with bands or plates of white silica, which forms in many cases a complete network to inclose the nickel mineral. Other speci- mens, however, of the same ore are quite massive, with the silica in nodules. In color it is a beautiful pale apple green, which darkens and becomes more translucent on immersion in water. It does not fall to pieces when placed in water, but gives off bubbles of air for some minutes. A piece placed on the tongue adheres strongly. It is not greasy to the touch. Streak pale green, When heated in a closed tube it becomes gray, and on platinum wire with borax gives the usual nickel bead. 86 MATERIALS OF ENGINEERING NON-FERROUS METALS. NICKEL ORE, B. This ore strongly resembles garnierite, except in its color being darker, and the fact that it is slightly unctuous to the touch. It falls to pieces with a sharp crackling sound when placed in water, splitting into conchoidal fragments, and, like the other ore, gives off air bubbles, but not to so great an extent. Heated in a closed tube it gives off water, loses its color and becomes gray. Before the blowpipe it gives the usual nickel bead. It is not so soluble in acids as the other variety, but in one of the shafts of the district was found a decomposed variety of this ore, which was quite soluble in acids. The analyses here given are the mean results of examina- tion of four different samples of each ore ; they show the percentage of nickel protoxide to be from 23.88 in A to 29.66 in B. The average yield of all that has been mined taking a fair sample is stated to be 11.20, which is a high average yield. These ores are silicates of nickel and magnesia from Douglas Co., Oregon. 50. Uses of Nickel. Nickel plating by the electric cur- rent was practised experimentally by Jacobi and Becquerel in 1862, but it was commercially practised by Isaac Adams, of Boston, some years later. The plating fluid is a solution of the double chloride or the sulphate of nickel and ammo- nium. The current is usually obtained from the magneto- electric machine. This has become, during late years, a very important industry, and nickel plating is adopted by all manufacturers of small articles of metal subject to corrosion and tarnishing. The malleability of nickel allows of its being chased as are silver and gold, and with the result of greater lustre, while the qualities of brilliancy, hardness, and durability, whether used solidly or in electro-plating, make it very suitable for table service. The sheet-nickel of commerce is as thin as o.oi inch USES OF KICKEL. 87 (0.025 cm.), and the wire is nearly as fine. It can be welded, with care, and can be forged like iron. Nickel coinage was commenced, about 1850, by Switzer- land, and in the United States in 1857. This application, and nickel plating by electrolytic action, absorb enormous quantities. The working of this metal has been most exten- sively carried on in the United States by Mr. J. Wharton, at Camden, N. J., from sulphuretted ores mined at Lancaster Gap, Penn. Sheets have been produced 6 feet (1.8 m.) long and 2 feet (6.1 m.) wide. Dr. Fleitmann's discovery, that a small dose of manganese added to the molten charge, when ready to pour into the moulds, renders the nickel sound, strong, malleable, and ductile, has greatly cheapened, as well as improved, the prod- uct. Fleitmann has welded together iron and nickel, and steel and nickel. Nickel is principally used in the arts in the manufacture of hollow ware which is to be plated with silver, as practised by Gorham, and for vessels of nickeled iron ; the latter are less liable to injury than when the nickel is deposited by electrol- ysis. Iron thus plated with nickel can be worked with nearly the same facility as either metal alone. Commercial nickel often contains iron. Canadian (Quebec) ores contained,* in the garnet, calcite, 50.40; chromite, 6.87; chrome garnet, 49.73, and in pyroxene, silicon and alumina, 50.60; iron oxide, 8.73; magnesium and calcium oxides, 35.90; water, 5.83. The reduced ore gave: iron, 71.84; nickel, 22.70. The slag contained no nickel. Commercial nickel contains, usually, measurable amounts of carbon, silicon, iron and often cobalt. The nickel plates now largely used as anodes for nickel plating are prepared by fusing commercial nickel, generally with addition of charcoal, and casting in suitable form. The subjoined analyses by Mr. W. E. Gard,f of such plates, show that silica may be reduced and retained as silicon, and that a considerable amount of carbon may be present : * " Nickel Ores " ; W. E. Eustis. Trans. Am. Inst. Min., Eng. f Am. Journal of Science and Art, 1878. 88 MATERIALS OF ENGINEERING NON-FERROUS METALS. NO I. NO. II. NO. in. a. V. a. b. a. b. .530 549 1. 104 1.080 i .900 1.830 .303 .294 .130 .125 .255 .268 .464 463 .108 .110 .301 .318 Cobalt .446 .438 trace trace 049 CK7 .266 . 340 . 104 .006 [Nickel] 98 . 208 08.190 98.392 98 . 345 Q7.44O 97,488 Total IOO.OOO IOO.OOO IOO.OOO IOO.OOO IOO.OOO IOO.OOO No. I. was American nickel, manufactured and cast by Jos. Wharton, at Camden, N. J. A careful examination by means of Marsh's apparatus showed not the least trace of arsenic or antimony. No. II. was a sample taken from a cast nickel anode used by a nickel-plating establishment in New Haven, No. III. a sample taken from the same anode after it had been used in the plating bath until upward of half its weight had been removed. Solvent action had ex- tended quite through the plate, leaving as usual a porous flexible mass retaining its original form. A comparison of Nos. II. and III. shows that under galvanic action the car- bon, silicon, and iron of the anode dissolved relatively slower than nickel, while the reverse happens with sulphur. 51. Aluminum ; or, Aluminium (AL; atomic weight, 27.5), is a white silver-like metal, very malleable and ductile, a good conductor of both heat and electricity, uniting with oxygen only with great difficulty, and therefore little liable to cor- rosion either by exposure to air or to the action of the oxygen acids. It dissolves freely in hydrochloric acid and in solutions of the alkalis. It is remarkable for its lightness ; its specific gravity being 2.6 to 2.7. The salts of this metal are not expensive, and are used in large quantities in the arts ; the sulphate, alum, is the most useful, and finds its most important applications in dyeing and calico printing. The alloys of aluminium are very valuable. Its remarkable lightness, combined with its strength, make it useful as a ALUMINUM; OR, ALUMINIUM. gg alloys. Equal volumes have equal strength when steel has about 80,000 pounds tenacity. Specific heat (Richards), 0.227. This metal was discovered by Wohler, in the year 1827, and by him obtained in considerable quantity, twenty years later, by reduction with sodium. Deville obtained it in ingots on a commercial scale, and the metal rapidly became familiar to chemists. Rose, in 1855, found that it could be obtained from cryolite, in which it exists as a fluoride, by reduction with sodium. Reduction with carbon or hydrogen has not succeeded. Cowle's process of reducing compounds of alu- minium, copper, and other metals in the " electric furnace " produces these bronzes and alloys at far less expense than earlier methods, and has introduced a great variety of alloys into the market at moderate prices. Sulphuretted hydrogen gas, which readily tarnishes silver, forming a black film on. the surface, has no action on this metal. Next to silica, the oxide of aluminium (alumina) forms, in combination, the most abundant constituent of the crust of the earth, in the form of hydrated silicate of alumina, clay. Common alum is sulphate of alumina combined with another sulphate, as potash, soda, etc. It is much used as a mordant in dyeing and calico printing, also in tanning. Aluminium is of great value in mechanical dentistry, as, in addition to its lightness and strength, it is not affected by the presence of sulphur in the food. Dr. Fowler obtained patents for its combination with vulcanite as applied to dentistry and other uses. It resists sulphur in the process of vulcanization so perfectly as to make it an efficient and economical substitute for platinum or gold. The metal, aluminium, is distinguished from other white metals by its peculiar gray-white color, differing from both zinc and tin, and especially its remarkably low density, pos- sessing as it does, but one-third the weight of copper, one- fourth that of silver, and one-eighth that of gold. It has a pleasant metallic ring when struck, and confers a beautiful tone when introduced into bell-metal. Deville made a bell of but 44 pounds (20 kilogs.) weight, which was, however, one and a half feet in diameter (^ metre), and exhibited an 90 MATERIALS OF ENGINEERING NON-FERROUS METALS. exquisite timbre ; it was presented to the Royal Society in 1868. It is sufficiently malleable and ductile to permit its being rolled into thin sheets and drawn into fine wire. Its melting point is at, or near, 1,300 F. (700 C. nearly), between the fusing point of silver and zinc, and it does not evaporate at any temperature yet observed. The metal may be worked cold, like copper or soft brass, and may be coined perfectly and easily. Oxidation occurs very slowly and it retains a polish as well as silver. It has often been proposed for use in coin, for which purpose it is well adapted by its beauty, lightness, sonority, and non-oxidizing quality. Laboratory weights have been made of the metal, and have remained standard for many years. Its solubility in the solutions of the Alkalis is, as with copper and silver, such as to prevent its use for some purposes. It is very extensively used in making fine articles of luxury, and is proposed for use for philo- sophical and engineering apparatus, and for utensils to be used in the household. Alloys of aluminium with other metals, with the excep- tion of copper, are little known and are not in use. There are several manufactories of the metal producing a half ton, or less, annually. Its cost is five per cent, of that of silver ; that of the bronze is five per cent, of that of the metal and somewhere about that of copper-tin bronze. See page 305. 52. Mercury (Hydrargyrum ; Hg.), often called quicksilver, is used by the engineer for a number of important purposes. It is a dense fluid metal, having an atomic weight, 200, a specific gravity of 13.6, a specific heat of 0.032 to 0.0333 as it passes from the solid to the liquid state, a coefficient of ex- pansion, according to Regnault, of from 0.00018 to 0.000197 as its temperature rises from the freezing point of water, 0, to 350 Cent. (32 to 662 F.) Its latent heat of fusion is 2.82 metric units per unit of weight (5.08 British). It boils at about 350 C. (662 F.), forming a colorless, transparent, poisonous vapor, and evaporates at all temperatures. The density of its vapor, according to Dumas, is 6.976. It unites freely, at ordinary temperatures, with several other metals MERCURY. 91 forming " amalgams." Iron and platinum are not among these metals. Mercury is therefore preserved in iron bottles. The Ores of Mercury are cinnabar, "vermilion," which is the sulphide, and calomel, the chloride ; the former is the usual source of the mercury of commerce. The metal is sometimes found native, in small quantities ; it is fre- quently alloyed slightly with silver. The ores of mercury are principally mined in California ; but large quantities are produced also in Spain, Austria, and China. Mercury, or " Quicksilver," is only produced in the United States, in California, where it is obtained from the red sul- phide (cinnabar). The quantity produced is not far from 60,000 flasks of 76^ pounds each, per annum, and one-fourth as much more is imported. Its principal use is in the manufac- ture of vermilion (sulphide of mercury), and amalgamating mirrors. Cinnabar is dark brown in color, earthy in texture, and very heavy, its specific gravity being 8.2 ; abrasion produces a red powder and a red streak on the mass. The ore is reduced by distillation and usually with considerable loss of vapor. The ore is broken up into pieces somewhat larger than an egg, and roasted in a deep furnace, of circular form, closed at the top and connected by flues with a set of con- densing chambers in which the mercury is condensed by contact with iron plates, over which cooling streams of water are kept flowing. The charges weigh 700 or 800 pounds (318 to 363 kilogrammes), and are worked off in about three- quarters of an hour; the fuel used per charge is 25 or 30 pounds (i 1.3 or 13.6 kilogs.) of charcoal. In some cases, as in India, a reverberatory furnace is used in reducing the cinnabar, when the ore is lean. In still other cases, lean ores are dis- tilled in small iron retorts, holding about 70 Ibs. (32 kilogs.), with lime, and the vapors are condensed in stone bottles half filled with water, or, the retorts are larger and contain as much ore as the furnace above described. Condensation is effected in a " hydraulic main," kept cool by immersion in a trough of water. Mercury, as distilled, usually contains bismuth, lead, and 92 MATERIALS OF ENGINEERING NON-FERROUS METALS. zinc, and is often re-distilled in the iron bottles in which it is purchased from the smelter, or purified by washing with dilute nitric acid. A subsequent washing with water and drying with filter-paper and then warming it, leaves it in good condition. It is also purified by shaking with powdered sugar or with charcoal, the impurities being thus oxidized out by contact with air. This metal is used in many kinds of philosophical appa- ratus, in the pressure gauges used for standardizing steam gauges, in the barometer, in " silvering " mirrors, and in a few alloys. Mercury was the last metal discovered by the ancients, and is supposed to have been known four or five centuries before the Christian era. Red cinnabar, its sulphide, was, however, used as a cosmetic several hundred years earlier, and was imported into Greece and Italy, in enormous quanti- ties, from the Spanish mines of Almaden. The Peruvians made similar use of it at the time of the discovery of their country by Pizarro. 53. Platinum (Pt.) is a metal possessing qualities of the highest value in the arts ; but its considerable cost forbids its common use. It is so named from the Spanish platina, the diminutive of plata, silver, because of its white, silvery color. It is found in the mountainous portions of South America, Central America, Mexico and California, in the West Indies, and in the Ural Mountains, in the metallic state, but mingled with ore of iron, copper, and the rarer metals, and usually alloyed with a small quantity of indium. Its atomic weight is 197.4. The metal is purified by solution in a mixture of nitric and hydrochloric acids, precipitation by potassium chloride of the double chloride of potassium and platinum, re-solution by nitro-hydrochloric acid and reprecipitation by sal-ammoniac, sometimes, after repeated solution, as the double chloride of ammonium and platinum. The volatile element is driven off by heating, and the " spongy platinum " remaining is welded into a solid mass, after cleansing by trituration and washing. Commercial Platinum always contains osmium and usually PLATINUM. 93 silicium and iridium. Fusion in the oxy-hydrogen flame with proper fluxing removes these metals by oxidation and the promotion of slag. Deville and Debray fuse the ore with galena in a small reverberatory furnace, and, fluxing with glass and litharge, obtain an alloy of lead and platinum nearly free from other metals. This is expected to remove the lead, and the platinum so obtained is refined on the lime-covered hearth and thus obtained in a very pure state. Various other ways are sometimes practised. The best method of compacting the metal is by fusion, which can be accomplished by the oxy-hydrogen flame in a little furnace made by forming a cavity between blocks of lime. Platinum is nearly as ductile as gold and silver, and is only exceeded in malleability by those metals and copper. It is white like silver and has nearly as high a lustre. It is softer than silver and about as hard as copper; but it is rapidly hardened by the addition of traces of iridium or of rhodium. Its specific heat is 0.03243 at common tempera- tures, according to Regnault. The coefficient of expansion is 0.0000068 per degree, Cent., according to Calvert and Johnson, 0.0000085 per Bordaz, o.oooooi according to other authorities, varying according to purity and physical condi- tion. Platinum can only be fused by the oxy-hydrogen flame or the voltaic arc. It is the heaviest of the metals used in the arts, having a specific gravity of 21.15 to 21.5. This metal is not oxidizable in the air or by any acid, although a mixture of nitric and muriatic acids will slowly dissolve it. At high temperatures, alkalis will produce corrosion by con- tact with it, as will potassium sulphate, and sulphur, phosphorus and arsenic. Chlorine attacks it slightly, iodine and bromine not at all. Platinum is principally used in the manufacture of vessels required to resist heat or the action of acids, as crucibles, evaporating basins, stills or retorts used in the concentration of sulphuric acid, etc. Carbon and silica corrode it, and the metals, generally, freely alloy with it ; its applications are thus somewhat restricted. Platinum was discovered by the Spaniards, in the sixteenth 94 MATERIALS OF ENGINEERING NON-FERROUS METALS. century, in the gold mines worked at the time, on the Isthmus of Darien ; it only became valuable in the arts two centuries later, after Sickengen had, in 1772, found that it could be welded at a single white heat ; it then came into demand, its hardness, strength, freedom from liability to oxidation, and especially its infusibility, giving it a value nearly equal to that of gold. 54. Magnesium, (Mg.; atomic weight, 24) is a silver white, lustrous metal, ductile and malleable, very light (s. g., 1.75), readily combustible, easily cut and worked, and resem- bling alumina in many respects. It melts and volatilizes like zinc, and at about the same temperature. In the form of powder or thin wire or ribbon, it takes fire like a shaving of wood and burns rapidly, with an intense bluish white light very rich in actinic rays. It abounds in dolomitic limestone in the form of silicate and carbonate of magnesia, in carncllite, a double chloride of magnesium and potassium, from which it is reduced by sodium, using fluor spar as a flux, purifying it by distillation. Magnesium has been manufactured by two establish- ments, the American Magnesium Company, Boston, United States, and the Magnesium Metal Company, Manchester, Great Britain. The English manufactory produced by far the most. The former furnished large quantities for the English army during the campaign in Abyssinia, the metal being employed extensively for signals. Magnesium can readily be ignited at the flame of a candle. Combustion is frequently interrupted by the dropping off of the burning portion, so that it becomes necessary to feed the unburnt portion into the flame continually. The wire burns to the best advantage if inclined at an angle of about 450. An uninterrupted and very brilliant combustion is produced by lamps especially constructed for this purpose. Such a lamp* is made by the American Magnesium Company. The strips of magnesium are rolled up on cylinders in the upper part of the apparatus. These strips are unrolled by clockwork * From designs patented by R. H. Thurston, 1865. New Marine Signal Light : Journal Franklin Institute, 1866. ARSENIC. 95 in the lower part of the apparatus, and are carried between two small rollers, the uniform motion of which feeds them regularly into the lamp, where they are ignited. The ashes are cut off at intervals by means of eccentric cutters, and collect in the bottom of the apparatus. A small chimney is added, which is very important, as producing a draught of air directly through the flame. A portion of the products of combustion is thus carried away, and the flame becomes very intense, while it is less so without a draught. This lamp has been found very efficient, especially for marine signals. At trials made at sea, on two vessels stationed eight miles apart, the signals could be readily distinguished ; it is said to be visible 28 miles. Larkin has constructed and patented a lamp in which the magnesium is not employed as wire, or in strips, but as a powder. By this means the clock-work, or other mechanical device, has been dispensed with. The metallic powder is contained in a reservoir, which has a small opening in the bottom. The magnesium powder flows through this like the sand in the sand-clock. It is intimately mixed with a certain quantity of fine sand, in a manner diluted ; first, in order to be able to make the opening sufficiently large ; furthermore, to produce a continuous flow of the material. The mixture falls into a metallic tube, through which illuminating gas is led from the upper end. The mixture is ignited at the lower end. The flame is very brilliant, and the remaining sand falls into a vessel placed below, while the smoke passes away through a chimney. A lamp of this character was adopted in several forms of signal apparatus devised for the Army and the Navy Signal Corps, by the Author, in the years 1866-70. 55. Arsenic (As.; atomic weight, 75) is found native, but is usually obtained from the sulphite or from the alloy with iron known as arsenical iron. It is also found alloyed with other metals. It is reduced from arsenical pyrites, or from arsenical iron, by roasting in retorts, the arsenic passing off by subli- mation and condensing outside as in the zinc manufacture. The arsenic of commerce is made principally from German 96 MATERIALS OF ENGINEERING NON-FERROUS METALS. and Spanish ores. The oxide is easily reduced by heating with carbon. This metal is a gray, lustrous solid, of steely fracture and color, having a density of 5.6 to 5.95, crystallizing in rhombohedra, volatilizing at a red heat, with a garlic-like odor, and oxidizing easily at a high temperature, but not readily at a low temperature. It has no value in the arts of construc- tion and engineering except in alloys. 56. Iridium (Jr.; atomic weight, 197) is the heaviest of useful metals. It was discovered in the year 1803 by Tennant, who analyzed the metallic residue which remains when platinum ores are dissolved. Tennant proved that the platinum residues contained two new metals, to one of which he gave the name of indium, on account of the varying color of its salts, and to the other the name osmium, because of the peculiar odor which its volatile oxide possesses. Iridium is found in the platinum ores in considerable quantity in the form of the alloys of platiniridium and osmiridium. The first of these occurs in grains and small cubes with rounded edges ; the second, usually, in flat, irregular grains, and sometimes in hexagonal prisms. Iridium, in the cold state, resists the action of acids and alkalies. It parts with its oxygen at a high heat, and, although it possesses a number of valuable qualities, has been used, until recently, only for the points of gold pens. Its limited use was caused by the difficulty of obtaining it in metallic form. It is found in Russia, Brazil, California and several other countries, and is usually accom- panied by gold or platinum. Since its discovery, numerous chemists and metallurgists have unsuccessfully endeavored to reduce the ore and obtain iridium in the metallic form. Chemists have succeeded in producing some small pieces of iridium the size of a pea by means of the oxyhydrogen blow- pipe flame, the metal obtained, however, being porous and valueless. In 1855, George W. Sheppard, of Cincinnati, suc- ceeded in producing a similar result with the aid of a power- ful galvanic battery. Later, John Holland, of that city, began experimenting in the same direction, and after several years of trial succeeded in reducing the iridium ore to a solid MANGANESE. 97 metal in common furnaces. He used phosphorus as a flux, by means of which, it was said, the metal could be made to fuse as easily as cast iron. This new method of fusing iridosmine was discovered in 1881 ; it consists in heating the ore to whiteness and adding phosphorus. The mass becomes at once fused, and the phos- phide thus obtained is reduced by heating with lime. The metal is exceedingly hard, has a brilliant metallic lustre and is not attacked by acids; when pure, its density is 18.7.* The ore used as above, and the metal, have been examined by Clarke and Joslin.f The ore has a specific gravity of 19.182, the metal 13.77. The composition of the latter was Indium 80.82 Osmium 6.95 Phosphorus 7.09 Ruthenium, Rhodium 7. 20 102.06 showing the fused metal to be a phosphide, of the formula, Ir,P. Phosphorus was found to re-act similarly with platinum. 57. Manganese (Mn. ; atomic weight, 55) is usually found as a peroxide, although occurring in many other com- pounds. Its oxide is reduced by carbon at a white heat, usually by heating the peroxide in powder with oil. The metal is also obtained by heating the chloride or fluoride with sodium. It is gray in color, resembling light gray cast iron, usually weak and brittle, heavy (s. g., 7 to 8) and slightly magnetic. It has a strong affinity for oxygen, and it is this which makes it valuable in the arts. In one of its forms it is quite different, however. As reduced from the chloride by sodium it is hard and does not easily oxidize. Manganese is always used as an alloy. Its most usual form is seen in " spiegeleisen" an alloy with iron used in the * Proc. Ohio Mechanics' Institute, 1882. f Am. Chemical Journal, vol. v. No. 4, 1883. Qo MATERIALS OF ENGINEERING NON-FERROUS METALS. Bessemer and other processes of steel-making, which is made by direct reduction from manganiferous ores by the ordinary small charcoal blast-furnace. It is cast either into pigs or into flat plates. When very rich in manganese and ccmpari- tively low in carbon, it is called " ferro manganese." Spie- geleisen contains from 3 or 4 to 8 or 10 per cent, manganese, while ferro-manganese contains 10 to 30 per cent. 58. The Rare Metals are of no value to the engineer in his everyday work ; they are enormously costly, and possess, as a rule, none of the qualities which are essential to their use in construction. They are here only referred to, to com- plete the list. Gold and silver are too well known to demand description. They are both dense, but soft, metals, difficult of oxidation, little subject to corrosion, and therefore sometimes very use- ful in plating other metals not readily attacked by acids, alloying with copper and some other metals readily, and forming compounds which, like these metals themselves, are of little or no value to the engineer. Cadmium is a white, malleable and ductile metal resem- bling tin. Its sulphide, known as cadmium yellow, is bright in color and has qualities of great value to artists. The metal is of little use. Calcium is yellow, ductile and malleable, and softer than gold. At a red heat it burns with a dazzling white light. Erbium is very rare ; it resembles aluminium in its proper- ties and compounds. Glucinum is white, malleable and moderately fusible, re- sembling aluminium. Lithium is a metal resembling silver in color. It admits of being drawn into wire, but has little tenacity. It is remarkable for its lightness and the readiness with which it combines with oxygen. Molybdenum is a silvery white, brittle and infusible metal. It never occurs native, and neither it nor its compounds are of practical use. Osmium is remarkable for its high specific gravity and infusibility. COMMERCIAL METALS. 99 Palladium resembles platinum. An alloy of 20 per cent, with 80 per cent, gold is perfectly white, very hard and doe? not tarnish by exposure. Rhodium is white, very hard and infusible. Its specific gravity is about n. Ruthenium resembles indium. It is rare and of little value. Strontium is yellowish, ductile and malleable ; it burns in the air with a crimson flame. Thallium is very soft and malleable. Thorium is an extremely rare metal, remarkable for taking fire below red heat, and burning with great brilliancy. Neither the metal nor its compounds are of practical use ; its oxide has the high specific gravity of 94. Titanium is a rare metal, usually obtained in crystalline form, and also as a heavy iron-gray powder. The crystals are copper-colored and of extreme hardness. Tungsten is a hard, iron-gray metal, very difficult of fusion. An alloy of ten per cent, of this metal and 90 per cent, of steel is of extreme hardness. Both the metal and its compounds have proved of value alloyed in steel and bronze. Uranium is very heavy and hard, but moderately mallea- ble, resembling nickel and iron ; it is unaltered at ordinary temperatures by air or water. Rubidium and caesium so closely resemble platinum that no ordinary test will distinguish them. Indium is very soft, malleable and fusible ; it marks paper like lead. Barium, cerium, columbium (or niobium), didymium, lan- thanium, tantalum, terbium, yttrium, and zirconium, are all rare metals and not very well known. 59. The Commercial Metals are never chemically pure. Lake Superior copper and the best lead and tin are practi- cally so, but all other metals have such a variety of quality and composition, as sold in our markets, that the purchaser and consumer can only rely upon careful analyses to deter- mine their value for any proposed use. This precaution is 100 MATERIALS OF ENGINEERINGNON-FERROUS METALS. especially advisable when the engineer selects metals of alloys for use in construction. Thus copper has been found to contain as much as 30 per cent, lead and 8 or 9 per cent, of nickel, iron, arsenic, and other metals ; lead often contains several per cent, of antimony, arsenic, zinc, and other elements ; iron may con- tain besides the sulphur and phosphorus which frequently seriously injure it, a considerable amount of manganese, chrome, nickel and cobalt, and even copper ; platinum often contains appreciable quantities of the other rare metals, as paladium, rhodium, usually iridium and osmium, and some- times iron and copper ; zinc is very frequently rendered use- less for the engineer's purposes by the presence of lead. The Prices of Metals are so constantly varying that no list can be given of great accuracy. The cost of reduction, the relations of supply and demand, and the accidental fluctu- ations of the market combine to determine the exact figures. The following table, calculated by Bolton,* may be taken as representing approximate values. PRICES OF METALS. METAL. STATE. VALUE IN GOLD PER LB. AVOIRDUPOISE. PRICE IN GOLD PER GRAMME. AUTHORITY. Vanadium . $J. 7Q2 J.O $10 80 g Rubidium Wire 3 261 60 7 2O s Calcium 2 446 2O 5 JO Q Tantalum . Pure 2 446 2O SAO s Cerium Fused globule 2 446 2O SAO s Lithium 2228 76 s I>ithium Wire 2Q-2C A A 6 48 s F^rbium Fused I 671 ^7 306 s Didymium 1 630.08 3.60 s Strontium. Electrolytic I ^ 76 AA o 18 s Indium Pure I 52^ 08 3q6 T Ruthenium I "3O4 64 2.88 T Columbium Rhodium Fused 1,250.28 I O^ 8<1 2.76 2 28 S. T Barium O2J. 12 2OA s Thallium 7^8 ^Q I 6l T Osmium 6C2 ^2 1 .44 T Palladium do8 ^o I IO T * Engineering and Mining Journal, Aug. 21, 1875. THE PRICES OF METALS. PRICES OF METALS. Continued. IOI METAL. STATE. VALUE IN GOLD PER LB. AVOIRDUPOISE. PRICE IN GOLD PER GRAMME. AUTHORITY. SU66.5Q Si o*? T 434.88 06 T. Gold 2QO 72 Titanium . Fused O-IQ go ro Tellurium fi I Annalen, vol. 89, 1853, pp. 497-531. \ Phil. Trans., 1858, pp. 349-368. PROPERTIES OF THE ALLOYS. IIQ proportions of the metals composing them. They found also that the conducting power of metals was different when they were rolled out into bars or cast, and that it was modified by molecular arrangement or position of the axes of crystalli- zation, as was shown by the different conducting power of metals cast horizontally and vertically. Some curious results were observed in regard to alloys of gold and silver. Silver being the best conductor, its conductivity is rated as 1,000, and that of gold the next, is 981 ; but gold alloyed with I per cent, of silver has a relative conductivity of only 840. The conduction of heat by alloys, according to Calvert and Johnson, may be considered under three general heads: 1. Alloys which conduct heat in ratio with the relative equivalents of the metals composing them. 2. Alloys in which there is an excess of equivalents of the worse conducting metal over the number of equivalents of the better conductor, such as alloys composed of I Cu and 2 Sn, I Cu, and 3 Sn, etc., and which present the curious and unexpected rule that they conduct heat as if they did not contain a particle of the better conductor, the conducting power of such alloys being the same as if the bar was entirely composed of the worse conducting metal. A not less remarkable fact is that the alloys of a series, such as those of 2 equivalents of bis- muth and I of lead, 3 Bi and I Pb, 4 Bi and I Pb, all conduct heat alike, the various increasing quantities of lead exercis- ing no influence on the conductivity. The results obtained with this class of alloys are most im- portant to engineers ; for it will be seen in the case of alloys of brass and bronze that no increase is gained in the con- ductivity of an alloy by increasing the quantity of a good conductor; nay, in many cases it would be a decided loss, unless a sufficient quantity of the better conducting metal be employed to bring the alloy under the third head. 3. Alloys composed of the same metals as the last class, but in which the number of equivalents of the better conducting metal is greater than the number of equivalents of the worse conductor ; for example, alloys composed of I Sn 2 Cu, I Sn 3 Cu, etc. In this case each alloy has its own arbitrary con- 120 MATERIALS OF ENGINEERING NON-FERROUS METALS. ducting power ; the conductivity of such an alloy gradually increases and tends toward the conducting power of the better conductor. In a later experiment upon the conductivity of mercury and the amalgams, Calvert and Johnson* discovered that they had committed an error in their first experiments in determining the conductivity of mercury, by disregarding the fact that convection of the liquid increased the apparent con- ductivity. In the first experiments they found the apparent relative conductivity to be 677, silver being 1,000; but in the later experiments they determined the real relative con- ductivity to be only 54, or less than that of any other metal. In regard to the fluid amalgams, they found in all cases that their conductivity was nearly the same as that of pure mer- cury. Weidemann,f in 1859, published a paper in which he calls in question the accuracy of the results found by Calvert and Johnson, and criticises the apparatus used by them and the small size of the bars upon which they experimented. He also gives the results of some experiments which he has made upon the conductivity of a few alloys. Matthiessen \ describes a simple apparatus for showing the different conductivities of alloys. He also states that the conductivity for heat furnishes no evidence of whether an alloy is a chemical compound or a mixture. 68. Conductivity for Electricity. The conductivity for electricity, like the conductivity for heat, is one of the prop- erties which, in some alloys, is the mean of that of the com- ponent metals, and in others seems to have no relation what- ever to such mean. There have been a large number of experiments made upon the electric conductivity of the alloys, but in this, as in the examination of other properties, with widely varying results. In the first place, the determinations of the con- ducting powers of the metals themselves are far from agree- * Phil. Trans., 1859, PP- 831-835. t Pgg- Annalen, vol. 108, 1859, pp. 393-406. \ Jour. Chem. Soc.,vo\. 5, 1867, p. 213. PROPERTIES OF THE ALLOYS. 121 ing; as, for instance, the conductivity of copper, according to different experimenters, is given at numbers ranging from 66 to 100, pure silver being 100. Again, Matthiessen * has shown that small traces of the metals, and especially of the metalloids, reduce the conduc- tivity of copper to a great extent. He states also, that there is no alloy of copper which conducts electricity better than pure copper, and that the fact of the wires experimented upon being annealed or hard drawn causes a marked differ- ence in the values obtained, annealed wire being a better conductor than hard drawn ; and, further, that temperature has likewise a marked influence, the metals losing in conduct- ing power as the temperature increases. In 1833, Professor Forbes f published the statement that the order of conducting powers of the metals for heat and for electricity is the same. He states, as a general conclusion, " that the arrangement of metallic conductors of heat does not differ more from that of those of electricity than either arrangement does alone under the hands of different ob- servers." Twenty years later, Weidemann and Franz J arrived at the same conclusion in regard to brass and German silver, and Weidemann, in 1859, concluded tne same in regard to alloys in general. Weidemann and Franz remarked that whatever the quality may be upon which calorific conduction depends, the close agreement of the figures renders it exceedingly prob- able that the same quality influences in a similar manner the transmission of electricity; for the divergence of the numbers expressing the conductivity for heat from those ex- pressing the conductivity for electricity are not greater than the divergences of the latter alone, exhibited by the results of different observers. The most extensive series of investigations upon the electric conductivity of alloys has been made by Matthiessen. * Phil. Trans., 1860, pp. 85-92. f Phil. Mag., vol. 4, 1834, p. 27. \ PS&' Annalen, vol. 89, 1853, pp. 497-531. Ibid., vol. 108, 1859, pp. 393-407. 122 MATERIALS OF ENGINEERING NON-FERROUS METALS. His results are published in the following papers: <4 On the Electric Conducting Power of the Metals ;" * " On the Elec- tric Conducting Power of Alloys ;"f " On the Influence of Temperature on the Electric Conducting Power of Alloys ;" \ "On the Thermo-Electric Series ;" "On the Effect of the Presence of the Metals and Metalloids upon the Electric Conducting Power of Pure Copper;"] "On the Chemical Nature of Alloys." 1 It was chiefly from these researches that Matthiessen arrived at the conclusions in regard to the question whether alloys are chemical compounds or mixtures, which have already been given under the head of the chemical nature of alloys. Matthiessen's examination of the conductivity of copper, made in 1860, greatly stimulated the refinement of the metal used in telegraphy and led to a gradual improvement, from a conductivity of less than 50 per cent, up to above 98 per cent., that of pure copper in the latest work. Good wire has highest conductivity when soft, but the strength of soft cop- per is often much less than one-half that of hard drawn wire. Use has no apparent effect on conductors of this metal, but it is at times subject to a peculiar change resulting in brittle- ness and loss of conductivity; this is especially liable to occur in electro-magnets. In regard to the conducting power for electricity of the alloys, Matthiessen divides the metals into two classes : Class A. Those metals which, when alloyed with one another, conduct electricity in the ratio of their relative volumes. Class B. Those metals which, when alloyed with one of the metals belonging to class A, or with one another, do not conduct electricity in the ratio of their relative * Phil. Trans., 1858, pp. 383-387. f Phil. Trans., 1860, pp. 161-176. \ Phil. Trans., 1864, pp. 167-200. Phil. Trans., 1858, pp. 369-381. | Phil. Trans., 1860, pp. 85-92. *f British Assoc. Reports, 1863, pp. 37-48. PROPERTIES OF THE ALLOYS. 123 volumes, but always in a lower degree than the mean of their volumes. To Class A belong lead, tin, zinc, and cadmium. To class B belong bismuth, mercury, antimony, platinum, palladium, iron, aluminium, gold, copper, silver, and in all probability most of the other metals. 69. Crystallization. The crystallization of alloys exhibits some curious phenomena. It was formerly supposed that if a distinct crystal of an alloy were found, it would have a definite chemical composition, and would show that the alloy was not a mixture, but a veritable chemical compound. In 1854, however, Prof. J. P. Cooke* published a paper on two crystalline compounds of zinc and antimony, which exhibited such properties as justified him in considering them definite chemical compounds. To distinguish them, he gave them the names of Stibiotrizincyle, with the formula Sb Zn 3 , and Stibiobizincyle, with the formula SbZn 2 . In the paper named, the crystalline form and other properties are fully described. A short time afterward it was found that well-defined crystals, like those described as SbZn 3 , were obtained from the alloys containing between 43 and 60 per cent, of zinc ; and even in alloys of a higher zinc percentage crystals of the same form were still seen, although they were no longer well defined. In the alloys containing between 20 and 33 per cent, of zinc, well-defined crystals, like those described as Sb Zn a , were formed ; and finally, there separated from the alloys containing between 33 and 42 per cent, of zinc, thin metallic plates, which evidently belonged to the same crys- talline form, f The same fact has been observed by Matthiessen and Von Bose $ in regard to the alloys of gold and tin, namely, that well-defined crystals are not limited to one definite propor- tion of the constituents of an alloy, but are common to all gold-tin alloys containing from 43 to 27.4 per cent, of gold. * Am. Jour. Art and Set., vol. 18, 1854, pp. 229-237. f Ibid., vol. 20, 1855, pp. 222-238. J Proc. Roy. Soc., i86o-'62, pp. 433-436. 124 MATERIALS OF ENGINEERING NON-FERROUS METALS. They also found in the case of these alloys that the crystals and the mother liquor were never of the same composition, the percentage of gold in the mother liquor being much below that in the crystals. From experiments by F. H. Storer,* it appears that the alloys of copper and zinc yield crystals, sometimes exhibiting distinct octahedral faces, sometimes in confused aggregates of crystals, but all of octahedral character, and bearing a striking resemblance to the crystals of pure copper obtained by fusion. None of the crystals were found to contain a larger proportion of either metal than the remainder of the molten liquid from which they had separated. Storer con- cludes that all the alloys of copper and zinc crystallize in the regular system, and that they are not definite atomic com- pounds, but merely isomorphous mixtures of the two metals. Calvert and Johnsonf have also noticed the crystallization of the alloys of copper and zinc, and state that it is probable that Cu 2 Zn and Cu 3 Zn are definite compounds, as they are perfectly crystallized, and have also a special heat-conducting power of their own. They state that the most splendid of all the brass alloys is the alloy CuZn, which is of a beautiful gold color, and crystallizes in prisms often 3 centimetres long. Slow cooling of an alloy is apt to favor the separate crys- tallization of one or more of its components, and thus render it brittle. Sometimes in casting an alloy in large masses, there will be a partial separation of the constituents, and crystals of different composition will be found at the top and bottom of the mass, those at the bottom usually containing the larger percentage of the metal which has the greater specific gravity. This phenomenon has already been noted under the head of liquation. 70. Oxidation and Action of Acids. But few experiments have been made to determine the rate of oxidation or cor- rosion of the alloys by atmospheric influences or by the action of acids. It is generally found that the action of the atmos- phere is less on alloys than on their component metals. An * " Memoirs of the American Academy," vol. 8, 1863, pp. 27-56. f Phil. Trans., 1858, p. 367. PROPERTIES OF THE ALLOYS. 1 25 instance of this is the ancient bronze statues and coins, some of the latter of which have their characters still legible, although they have been exposed to the effects of air and moisture for upward of twenty centuries. The action of the atmosphere on an alloy heated to a high temperature is sometimes quite energetic, as is shown in the alloy of three parts lead and one of tin, which, when heated to redness, burns briskly to a red oxide. When two metals, as copper and tin, are combined, which oxidize at different temperatures, they may be separated by continued fusion with exposure to the air. Cupellation of the precious metals is a like phenomenon. Mushet* found that unrefined copper resisted the action of muriatic acid better than pure copper. This he thought was due to the presence of tin in the unrefined copper, as he found that an alloy of copper containing about 3 per cent, of tin resisted the action of acid to still greater extent. The latter he recommends for the purpose of ship-sheathing. Calvert and Johnsonf have made several experiments to determine the action of nitric, hydrochloric, and sulphuric acids upon alloys of copper and zinc and copper and tin. Some of the results thus obtained were entirely unexpected. Nitric acid of 1.14 specific gravity was found to dissolve the two metals in an alloy of zinc and copper in the exact pro- portion in which they exist in the alloy employed, while an acid of 1. 08 specific gravity dissolved nearly the whole of the zinc and only a small quantity of the copper. Hydrochloric acid of 1.05 specific gravity was found to be completely inactive on all alloys of copper and zinc containing an excess of copper, and especially on the alloy containing equivalent proportions of each metal. Zinc was found to have an ex- traordinary preventive influence on the action of strong sulphuric acid on copper. The alloys of copper and tin were all found to resist the action of nitric acid more than pure copper, but the preven- * Phil. Mag., vol. 6, 1835, pp. 444-447. t Ibid., vol. 10, 1855, pp. 250, 251 ; also, Jour. Chem. Soc., vol. 19, 1866, pp. 434-454- 126 MATERIALS OF ENGINEERING NON-FERROUS METALS. tive influence of tin presents the peculiarity that the action of the acid increases as the proportion of tin increases ; thus the alloy CuSn 5 is attacked ten times more than the alloy Cu Sn. The alloys SnCu 2 and SnCu 3 were attacked by strong sulphuric acid with more violence than an)/ other of the bronzes. Three alloys, viz., Cu l8 ZnSn, Cu IO ZnSn, and Cu 4 Zn 2 , were found to be only slightly attacked by strong nitric or hydrochloric acids, and not at all by sulphuric acid. The resistance to the action of nitric acid is remarkable, as its action on each of the component metals is very violent. A. Bauer * has also published, in the Berichte der deut- schen chemise/ten Gesellschaft, the result of some experiments on the action of hot sulphuric acid on several alloys of lead. These experiments show that the addition of a little antimony or copper renders the alloy more able to resist sulphuric acid, while bismuth has a decidedly injurious effect. 71. Hardness and other Mechanical Properties. The mechanical properties of the alloys, such as hardness, mallea- bility, ductility, resistance to strains of tension, compression, and torsion, elasticity, resilience, etc., are of the utmost im- portance to the engineer, but, at the same time, it is most difficult to find reliable information regarding them. But few experimenters of authority have investigated the subject, and their researches, although valuable as far as they go, are too limited in extent to allow of a complete classification and comparison. A few alloys which are of special service in the arts have been well studied by those who have had occasion to use them, with a view to learn their mechanical properties, not as a matter of scientific interest, but as an actual necessity. This has been the case especially with the various gun-metals, upon which many experiments have been made under authority of the different governments, so that among all the alloys our knowledge of the gun-metals is the most extensive and accurate. In like manner the properties of journal and anti-friction metals have been investigated by those who are concerned in their manufacture and use. * Scientific American, vol. 33, 1875, p. 135. PROPERTIES OF THE ALLOtt^ 12? With these, and a few other exceptions, however, our information on the mechanical properties of the alloys is very meagre. It has been the endeavor of the Author, as far as possible, to supply this manifest want by a series of experi- ments on a large number of alloys, testing them to deter- mine their mechanical properties. The hardness of some of the alloys has been investigated by Calvert and Johnson.* They used an apparatus for determining the hardness, which consists, chiefly, of a conical steel point of a certain size, which is pushed into the material whose hardness is to be determined a given distance by means of weights applied at the end of a lever. The relative hardness is shown by the weight required for the different materials. A somewhat similar apparatus was used by Major Wade f in determining the hardness of gun-metal, but he used a diamond-shaped point and a fixed weight, determining the relative hardness by the distance which the point was pushed into the metal. General Uchatius,J in experiments for the Austrian Government, used an indenting tool, which was forced into the metal to be tested by a weight of 4.4 pounds falling through a height of 9^ inches. The shorter the cut made by the indenting tool, the greater the hardness. Mallet in 1842, in his experiments on the alloys of cop- per and tin and copper and zinc, determined their tensile strength, and also the order of their ductility, malleability, and hardness. In his work on the " Construction of Artil- lery," | published in 1856, the same author discusses the physical and mechanical properties of gun-metal, showing the effects of sudden and of rapid cooling, and the deteriorat- ing effect of small proportions of a third metal, such as iron, zinc, lead, or antimony. In regard to the extent of our knowledge upon these sub- * Phil. Mag., vol. 17, 1859, pp. 114-121. f " Report of Experiments on Metals for Cannon," Phila., 1856. j Ordnance Notes No. XL., Washington, D. C, 1875. Phil. Mag., vol. 21, 1842, pp. 6-68. | Mallet, "Construction of Artillery," London, 1856, pp. 80-101. 128 MATERIALS OF ENGINEERING NON-FERROUS METALS. jects, he remarks : " Gun-metal, probably the very earliest used material for cannon, is that which has received the least improvement or systematization of our knowledge as to its use, up to the present time ; the archaeologist finds the rude weapons of Scandinavian, Celtic, Egyptian, Greek, and Ro- man warfare formed of nearly the same alloys of copper and tin, and in about the same proportions, as the cannon of to-day." The circumstances of chief difficulty and importance in the manipulation of gun-metal, as affecting the production of cannon, are : 1st. The chemical constitution of the alloy, as influencing the balance of its hardness, rigidity, or ductility, and tenacity. 2d. Its chemical constitution, and what other conditions influence the segregation of the cooling mass of the gun, when cast, into two or more alloys of different and often variable composition. 3d. The effects of rapid and of slow cooling, and of the temperature at which the metal is fused and poured. 4th. The effects due to repeated fusions, and to foreign constituents, in minute proportions, entering into the alloy. The circumstances of manipulation, as above named, have already been shown to have a vast influence upon nearly all the properties of the alloys, and their study is of the greatest importance, not only in reference to gun-metals, but to all alloys which may be used as materials of construction. In connection with the subject of gun-metal, the experi- ments lately made by General Uchatius * for the Austrian Government are of interest. He found that the tenacity, elasticity, and hardness of bronze were increased to an extra- ordinary degree by driving a series of conical steel mandrels or plugs, gradually increasing in size, into the bore of the gun. The metal in the interior of the gun was thus stretched or strained much beyond its elastic limit, and was thereby given a new molecular condition, which enables it better to resist both the expansive force of the exploded powder, and the abrading effects of the shot. The results of the experiments of General Uchatius have * Ordnance Notes No. XL., Washington, D. C., 1875. PROPERTIES OF THE ALLOYS. 1 29 been communicated to the Ordnance Department of the United States by Col. T. T. S. Laidley, U. S. A., who calls attention to the fact that experiments were made upon bronze, with a view to improve its quality for guns, by Mr. S. B. Dean, of Boston, in 1868-69, at which time he used the identical mode of improving the bronze adopted by General Uchatius some four years later. Patents for the improvement were secured in May, 1869, not only in this country, but also in England, France, and Austria. The want of funds rendered it necessary for Mr. Dean's experi- ments to be discontinued. This matter will be considered at greater length in a later division of this volume. 9 CHAPTER IV. THE BRONZES AND OTHER COPPER-TIN ALLOYS. 72. The Alloys of Copper, with smaller quantities of the more common metals, are the most valuable and the most common, and the most extensively used of all compounds or mixtures known to. the .engineer and the metallurgist. Those which are produced by the union of copper and tin are generally classed as the " Bronzes." When copper is alloyed with zinc, the composition is known as u Brass." These terms are not exclusively so applied, however, and the term brass is not infrequently used to cover the whole series of alloys com- posed, wholly or in part, of alloys of copper and tin, copper and zinc, or combinations of brass and of bronze with each other or with less quantities of other metals. Bronzes are here sup- posed to contain principally copper and tin. These alloys are produced by the union, either chemically or by solution, when molten, of two or more metals. Nearly all metals can unite with nearly all other metals in this manner, and the number of possible combinations is infinite ; nevertheless, but few alloys are found to be very generally used in the arts. It is consid- ered probable that the metals may combine chemically in definite proportions, but the compounds thus produced usually dissolve in all proportions in either of the constituents, and it is rarely possible to separate the chemically united portions. In some cases the affinity is very slight, as between lead and zinc, either of which will take up but about one and a half per cent, of the other. The alloys are usually the more stable as their constituents are the more dissimilar, and, when this dif- ference is chemically great, the compound becomes brittle. Occasionally, an alloy is formed which gives evidence of the occurrence of chemical union, by the production of heat; this is seen in some copper-zinc alloys. BRONZES AND OTHER COPPER TIN-ALLOYS. 131 Copper alloys are formed with nearly all metals with great facility, and with no other precaution than that of either preventing access of oxygen to the molten mass, or of thor- oughly fluxing the alloy, to take up such as may have com- bined with it. Many of these alloys were once considered chemical compounds ; but the view which seems most gener- ally accepted, at the present time, is that they are almost in- variably either mere mixtures, or that a species of solution of the one metal in the other takes place. The most minute trace of foreign element often produces an observable, or even an important, alteration of the proper- ties of copper. This is especially true of its conductivity for electricity, which is reduced greatly by an exceedingly minute proportion of iron or lead. 73. History. The alloys of these metals were used ex- tensively by the ancients for coins, weapons, tools and orna- ments, and the composition of their bronzes, as shown by recent analyses, indicates that they were as skilful in brass- founding as the modern workman. Thus, Phillips gives the following as the results of his own examinations and as showing the proportions of the constit- uents employed in the manufacture of brass, at times bofh preceding and closely following the Christian era : DATE. i ZINC. TIN. LEAD. IRON. o u Large brass of the Cassia family. . " Nero M .. B C. 20 A.D. 60 82.26 81.07 17.31 I7.8I 35 1.05 .... j " Titus " .. " 79 83.04! 15.84 ..... 50 " Hadrian " .. " I2O 85.67 10.85 I.I4 1-73 74 Faustina " .. " 165 79.14 6.27 4-97 9.18 23 Thus, copper and zinc were the essential constituents of the alloys examined ; but then lead was sometimes present in considerable quantities, together with tin andiron. Although zinc occurs in such considerable quantities in these alloys, it 132 MATERIALS OF ENGINEERING NON-FERROUS METALS. was not known in the metallic state until about the thirteenth century, when it was described by Albert of Bollstadt. Many analyses of ancient articles of bronze have been made, and our knowledge of this very old alloy is consider- ably greater than that of the alloys of zinc. The proportion of the constituent metals was varied according to the purpose to which the alloy was to be applied, as will be seen from the following analyses, the hardness being modified according to the proportion of tin present. The alloys containing the largest amount of tin were used for mirrors, while those of medium hardness were used for sword-blades and other cut- ting instruments : COPPER. TIN. LEAD. IRON. COBALT. ANALYST. i. Chisel, from ancient Egyptian quarry. 2 Bowl from Nimroud 94.00 80 57 5-90 .10 Wilkenson. Dr Percy 3. Bronze overlaying iron 88:37 ii 33 4. Sword-blade, Chertsey, Thames 5. Axe-head 89.69 88 cs 9-58 II. 12 ' '-78 33 J. A. Phillips. Prof Wilson 6. Celt 81.19 18.31 78 7. Roman As, B.C. 500 69.69 7.16 21.82 47 57 J. A. Phillips 8. Julius Caesar 8.00 12. 8l The third specimen was analyzed by Dr. Percy, who de- scribes it as a small casting in the shape of the foreleg of a bull, forming the foot of a stand, consisting of a ring of iron supported upon three bronze feet. A longitudinal section disclosed a central core of iron, around which the bronze had been cast. Some writers, to account for the immense masses of hard stone wrought by the Egyptians and ancient Americans, sup- pose that they possessed means of hardening bronze to a degree equal to that of our steel; this requires confirmation, since no remains of bronze of such a hard variety have ever been discovered. The bronze weapons discovered by Dr. Schliemann among the ruins excavated by him at or near the site of ancient Troy* were often of nearly the composition of modern gun- bronze ; they contained copper 90 to 96, tin 8.6 to 4. The date, * " Troy and its Remains ;" London and New York, 1875 ; p. 361. BRONZES AND OTHER COPPER-TIN ALLOYS. 133 archaeologically, is at the beginning of the " bronze age," and immediately at the close of the " stone age." Sir John Lubbock finds the bronze implements and ornaments of the bronze age as remarkable for their beauty and variety as for their utility.* They consisted of axes, arrow-heads, knives, swords, lances, sickles, ear-rings, bracelets, rings, etc., etc. The bronze used by the prehistoric nations contained no lead ; that of the Romans and post-Romans was rarely of pure copper and tin, but were usually more or less alloyed with lead. Silver, zinc, and lead was not known in the bronze age. The prehistoric bronzes were cast, sometimes in metal or in stone, and sometimes in sand, moulds. A more common method was by wax models, or " patterns," which were used to make the desired cavity in an earthen or sand mould, the wax being melted out afterward. According to Charnay,f the Aztecs discovered a means of tempering copper, and of giving to it a considerable degree of hardness, by alloying it with tin. Copper hatchets were known among them ; since Bernal Diaz states in the narrative of his first expedition to Tobasco, that the Spaniards bartered glass-ware for a quantity of hatchets of copper, which at first they supposed to be gold. Copper abounded in Venezuela, and we still find there in great numbers trinkets of copper mixed with gold, or of pure copper, representing crocodiles, lizards, frogs and the like. In cutting down trees, they employed copper axes like our own, except that, instead of having a socket for the haft, the latter was split, and the head of the axe secured in the cleft. The hatchet described seems to have been a piece of native copper wrought and fashioned with a stone ham- mer. The Aztecs made good bronze chisels, as described by Seftor Mendoza, director of the National Museum of Mexico. He describes certain specimens of bronze chisels belonging to the collection in that museum. When freed from oxide the bronze presents the following characteristics: In color it resembles gold ; its density is 8.875 '> Jt is malle- * " Prehistoric Times ; " London and New York, 1872. f N. A. Review, 1875 ; Ruins of Central America. 134 MATERIALS OF ENGINEERING NON-FERROUS METALS. able, but unlike pure copper, is hard, and breaks under strong tension or torsion ; the fracture presents a fine granulation like that of steel ; in hardness, it is inferior to iron, but it is sufficiently hard to serve the purpose for which it was in- tended. One of these chisels was found to consist of copper 97-87 per cent., tin 2-13 per cent., with traces of gold and zinc. The bronzes were used by the ancients in the manufacture of weapons and of tools. The use of phosphorus increases the purity and adds strength and hardness to these alloys, and the remarkable hardness of ancient bronze weapons is found by Dr. Reyer to be due, in part at least, to the presence of phosphorus, probably introduced with the flux used in melt- ing. The proportion of tin varied up to 20 per cent. 74. The Alloys of Copper and Tin have many uses in the arts. The two metals will unite to form a homogeneous alloy in a wide range of proportions. As tin is added to pure cop- per, the color of the alloy gradually changes, becoming decidedly yellow at 10 per cent, tin and turning to gray as the proportion approaches 30 per cent. In the researches conducted by the Author, it was found that good alloys may contain as much as 20 per cent. tin. When the color changes from golden yellow to gray and white, the strength as suddenly diminishes ; and alloys containing 25 per cent, tin are valueless to the engineer; nevertheless, this alloy and those contain- ing up to 30 per cent, show compressive resistances increas- ing to a maximum. The tensile and compressive resistances have no known relation ; the torsional resistance is more closely related to tenacity. A small loss of each constituent occurs in melting, the loss often being highest with the metal present in the lowest proportion ; this loss rarely exceeds one per cent., except when the fusion has taken place slowly with exposure to the air, when considerable copper-oxide is liable to form. The specific gravities of these alloys do not differ much from 8.95. Under 17.5 per cent, tin, the elastic limit lies between 50 and 60 per cent, of the ultimate strength ; beyond this limit the proportion rises, and at 25 per cent, tin the elastic limit BRONZES AND OTHER COPPER-TIN ALLOYS. 135 and breaking point coincide. Passing 40 per cent, tin, this change is reversed and the elastic limit, although indefinite, is lowered until pure tin is reached and a minimum at pjbout 30 per cent. The modulus of elasticity of all the bronzes lies between ten and twelve millions. Riche states that tempering produces on steel, forged or annealed, an inverse effect to that which it produces on bronzes rich in tin ; it diminishes its density instead of in- creasing it, from which it may be seen that tempering diminishes the density of annealed steel and makes it hard, while tempering increases the density of annealed bronze and makes it soft. There is always an increase in density, whether the bronzes rich in tin be tempered, or slowly cooled, after compression. These experiments confirm most clearly the fact affirmed by D'Arcet, that tempering softens the bronzes, rich in tin, for we can flatten in the press the tempered bronzes, while it is impossible to do this with steel. It is evident from his experiments that tempering aug- ments considerably the density of bronze rich in tin, and that annealing evidently diminishes the density of tempered bronze. Still the effect of slow cooling by no means destroys the effect of tempering, for the density continues to increase till it becomes remarkable. While all mechanical action increases the density of the annealed bronze, it very slightly, but still sensibly, diminishes the density of annealed steel, and, on the whole, tempering and shock increase the density of annealed bronze, while they diminish the density of annealed steel. But the variations are very decided for bronze and very slight for steel. Bronze of 96 and 97 parts copper may be employed to great advantage, and with no serious inconvenience, in the manufacture of medals. Its hardness, much less than that of the alloy of M. de Puymaurin, does not much exceed that of copper ; it possesses a certain sonority and casts well, rolls evenly, and its color is more artistic than that of copper. 136 MATERIALS OF ENGINEERINGNON-FERROUS METALS. The action of the press and of heat modify its density but little. 75. Properties. Copper and tin alloy in all proportions, and the most useful compounds known to the engineer are the " bronzes," as these alloys are called. They include gun- metal, bell-metal and speculum alloys. The following is Mallet's list of these alloys and table of their properties.* TABLE XIX. PROPERTIES OF COPPER-TIN ALLOYS. At. wt. : Cu. = 31.6 ; Sn = 58.9. AT. COM P. COPPER. S. G. COLOR. FRACT. TENACITY. MALL. HARD. FUS. Cu Sn per ct. Tons per sq. in. I O too. 8.607 red-yellow 24.6 I IO 16 a 10 b 9 84.29 82.81 8.561 8.462 Xi yellow-red fine grain 16.1 15.2 2 3 8 5 15 H c 8 81.10 8-459 ifc lt 17.7 4 4 13 d 7 78.97 8.728 pale red vitreous 13.6 5 3 12 e 6 76.29 8.750 " u 9-7 britrle 2 II f 5 72.80 8-575 ash gray conchoid. 4-9 " I IO i 4 h 3 i 63.21 61.69 51-75 8.400 8.539 8.416 dark gray white gray white lam. grain 0.7 0-5 *-7 friable brittle 6 7 9 I 7 j 34 -9 2 8.056 vitreous 1.4 u ii 6 k 21.15 7-387 lam. grain 3-9 lt 12 5 3 T 5-!7 7-447 " 3- 1 8 tough J 3 4 m 4 11.82 7.472 ** 3- 1 6 " J 4 3 5 9 63 7.442 earthy 2-5 7 J5 2 O 1 o. 7.291 2.7 16 I a, b, c are gun-metals ; d, hard brass for pins ; e, f, g, h, i, bell-metal ; /, k, for small bells ; /. m, , o, are speculum alloys. The addition of a small quantity of tin to copper causes it to become brittle under the hammer, according to Karsten, and the ductility is restored only by heating to a red heat and suddenly cooling. Mushet finds that the alloy, copper 97, tin 2, makes good sheathing, as it is not readily dissolved in hydrochloric acid. The best gun-metal is from copper 90, tin 10, to copper 91, tin 9 ; if richer in copper, it is especially liable to liquation, which action is detrimental to all these alloys. Bell-metal, copper 80, tin 20, to copper 84, tin 16, is sonorous and makes good castings, but is hard, difficult to * Dingier 's Journal, Ixxxv., p. 378 ; Watts's Diet, ii., p. 43. BRONZES AND TftER COFFER- TIN ALLOYS. 137 work and quite, brittle. Suddenly cooling it from a high temperature reduces its brittleness, while slow cooling re- stores its hardness and brittleness. It is malleable at low red heat and can be forged by careful management. Speculum-metal, copper 75, tin 25, is harder, whiter, more brittle and more troublesome to work than bell-metal. Old flexible bronzes contain about % ounce of tin to the pound of copper, or copper 95, tin 5, as stated by Ure. Ancient tools and weapons, as shown elsewhere, contain from 8 to 15 per cent, tin ; medals from 8 to 12 per cent., with often 2 per cent, zinc to give a better color. Mirrors con- tained from 20 to 30 per cent. tin. The metals mix in all proportions, and the alloys are, to a certain extent, independ- ent of their chemical proportionality. The occurrence of hard, brittle, elastic alloys between the extremes of a series having soft tin and ductile copper at either end, both of which metals are inelastic, is probably a proof that these alloys are sometimes chemical compounds. They are proba- bly, usually, compounds in which are dissolved an excess of one or the others of the components. 76. The Principal Bronzes are those used in coinage, in ordnance, in statuary, in bells, and musical instruments, and in mirrors and the specula of telescopes. These alloys oxid- ize less rapidly than copper, are all harder, and often stronger and denser. Coin bronze, as made by the Greeks and Romans, con- tained from copper 96, tin 4, to copper 98, tin 2, and Chaudet has shown that the first of these alloys can be used for fine work, obtaining medals of this composition of very perfect polish while sufficiently hard to wear well. Puymaurin succeeded well with alloys of copper 93.5, tin 6.5, to copper 90, tin 10; and Dumas found the range of good alloys for this purpose quite large, varying from 96 copper, 4 tin, to 86 copper, 14 tin, but the best falling near the middle of this range. Gun bronze has various compositions in different countries. The most common proportion would seem to be copper 90, tin 10, or copper 89, tin 11. Well made, it is solid, yellowish, denser than the mean of its constituents, and much harder, 138 MATERIALS OF ENGINEERING NOK-FERRO US METALS. stronger, and more fusible than commercial copper; it is somewhat malleable when hot, much less so when cold. It is subject to some liquation, and should therefore be quickly chilled in the mould ; it loses some tin when per- mitted to stand at a temperature of 400 to 500 Fahr. (200 to 260 C.). This liquation gives rise to light-colored spots throughout the metal. This bronze does not readily oxidize at ordinary temperatures, but is quickly attacked when hot ; it usually becomes greenish when exposed to the weather, by the formation of the hydrated carbonate ; thus " patina " is ob- served on all unpolished old bronze guns or old statues. Statuary bronze is usually of nearly the same composition as gun-bronze. It should be rapidly melted, poured at high temperature, and quickly cooled to prevent liquation. Bell-metal is richer in tin than the preceding, and varies in composition somewhat with the size of bell. The propor- tion, 77 copper, 23 tin, is said to be a good one for large bells ; it shrinks 0.015 in the mould while solidifying. The range of good practice is found to be from 1 8 to 30 per cent, tin, 82 to 70 per cent, copper ; the largest proportions of tin are used for the smallest bells, and an excess is added to meet the liability to oxidation and liquation; copper 78-82, tin 22-18, is a very usual composition. When made of scrap metal, as is not uncommon, serious loss of quality is liable to occur by the introduction of lead and other metals deficient in sonorousness. When properly made, this alloy is dense and homogeneous, fine-grained, malleable if. quickly cooled in the mould, rather more fusible than gun-bronze, but otherwise quite similar; excelling, however, in hardness, elasticity and sonority. These bronzes become quite malleable when tempered by sudden cooling, and this treatment is resorted to when they are to be subjected to prolonged working or to a succession of processes. Chinese gongs are made of copper 78 to 80, tin 22 to 20, and are beaten into shape with the hammer, the metal being softened at frequent intervals by heating to a low red heat and plunging into cold water. The tone desired is obtained by hammering the instrument until the proper degree of hardness is obtained. Tempering not BRONZES AND OTHER COPPER-TIN ALLOYS. 139 only increases the ductility and malleability of these alloys, but also, it is claimed, their strength, while decreasing their hardness and density, when they are made into thin sheets; thick plates are less affected ; annealing by slow cooling pro duces an opposite effect. Speculum-metal contains, often, as much as 33 per cent, tin ; it is steely, almost silvery white, extremely hard and brittle, and capable of taking a very perfect polish. The most suitable proportion of tin varies slightly with the character of the copper, some kinds requiring more and some less to give the degree of whiteness and the perfection of polish required. An excess of tin injures the color and reduces the lustre of the mirror. The finest speculum metal is perfectly white, without a shade of yellow, sound, uniform, and tough enough to bear the grinding and polishing without danger of disintegration. The specula made by Mudge were twice fused, and con- tained from 32 parts copper and 16 tin to 32 copper and 14.5 tin. A little tin is lost in fusion. According to David Ross, the best proportions are: copper, 126.4; tin, 58.9, i.e., atomic proportions. He adds the molten tin to the fused copper at the lowest safe temperature, stirring carefully, and secur- ing a uniform alloy by remelting, as is often done in making ordnance bronze. Bronze for bearings and pieces subject to severe friction, as in machinery, is made of many proportions. Gun-bronze is one of the best ; the Author has known of one case in which the bronze was made of ingot copper 90, ingot tin 10, and used in the main crank-shaft journal of a steam vessel for ten years without appreciable wear, although the area was not unusually large for the load and the velocity of rubbing was high, as is usual in screw engines. The proportions given in several cases will be found elsewhere ; they vary in practice from 88 to 96 per cent, copper, as more or less hardness is required. Bronze for steam engine packing rings is some- times made of 92 to 94 copper, 7 to 9 parts tin, I part zinc. 77. Old Bronze. According to Riche,* the analysis of * Appendix to U. S. Report on Tests of Iron and Steel, vol. i, p. 556. 140 MATERIALS OF ENGINEERING NON-FERROUS METALS. antique medals shows that, though the ancients sometimes used copper for this purpose, they ordinarily employed bronze in which the proportion of tin varied between wide limits (from I to 25 per cent.). The manufacture of medals with a bronze rich in tin is not practised at the present day, on account of its hardness, and because considerable relief is necessary, while this was very slight in the medals of antiquity. Bronze has been wholly given up and copper substituted for it ; but copper also presents some serious inconveniences. It rusts badly, does not ring when struck ; its red tint is not artistic, and this is concealed by an artificial bronzing which adheres poorly, and which causes different medals to vary in tone. In 1828, M. dePuymaurin made a large number of experi- ments, and continued them until 1832, after which an alloy of 94 copper, 4 tin, and 2 zinc was adopted in France, of which, from time to time, medals were manufactured until 1847, at which time it was entirely given up on account of the hard- ness of the metal leading to a deterioration of the coin. Riche advises a bronze containing 96 or 97 per cent, copper, and 4 or 3 per cent, tin, as less hard, more sonorous, capable of making good castings, and of working w r ell in the rolls, under the hammer, or in the dies; it has also a good color. 78. Oriental Bronzes. Analyses of Japanese bronzes, made by M. E. J. Maumene,* give the following: NO. I. NO. 2. NO. 3. NO. 4. CoDoer 86 -38 80 QI 88 70 Q2 O7 Tin I Q4 7. ec 2 58 I O4. Antimony. . I 61 O J.J. O IO I O4 Lead * 68 Srt 1 ! 1875. BRONZES AND OTHER COPPER-TIN ALLOYS. 141 These alloys are all of a granulated texture, blistered on the interior surface, sound on the exterior surface (which can be readily polished with a file). Their color is sensibly violet when antimony is abundant, red when iron is present. All the specimens were cast thin, from 0.195 to 0.468 inch, and the mould was well filled. It appears by analysis that these alloys were not made with pure metals, but with minerals. We should, says Maumene, consider these bronzes as result- ing from the use of copper pyrites, and antimonial galena mixed with blende ; and the calcination was not always com- plete, as the presence of sulphur in specimen No. 2 proves. Antique alloys, Greek, Roman, old French, etc., present similar indications. 79. Density of Bronzes. The increase of density above the mean of the densities of the two constituents, probably either due to the affinity of the metals, or freedom from air- cells, is exhibited by the following table, prepared by Briche : ALLOY. S. G. ACTUAL. CALCULATED. DIFF. Cop per i< X) ; t in 4 8.79 8.78 8.76 8.76 8.80 8.81 8.87 8.83 8.79 8.74 8-71 8.68 8.66 8.63 8.61 8.60 8-43 8.05 0.05 0.07 0.08 0.10 0.17 0.20 0.27 0.40 0.74 6 8 10 14. 16 o-j IOO The condensation of the alloy, due to the affinity of its con- stituents, or to greater homogeneousness, increases as the pro- portion of tin increases throughout the range above studied. 80. Ordnance Bronze. According to the U. S. Ordnance Manual, bronze used for ordnance consists of 90 parts of copper and 10 of tin, allowing a variation of one part of tin, more or less. It is more fusible than copper, much less so than tin, more sonorous, harder, and less susceptible of oxida- tion, and much less ductile, than either of its components. When the mixture is well made, the metal is homogeneous ; 142 MATERIALS OF ENGINEERING NON-FERROUS METALS. the fracture is of a uniform yellow color, with an even grain. The specific gravity of bronze is about 8.7, being greater than the mean of the specific gravities of copper and tin. Copper proposed to be used in ordnance bronze should be condemned for the manufacture of guns, if it contains sulphur in an appreciable quantity ; more than one-thou- sandth of arsenic and antimony united ; more than about three-thousandths of lead, iron, or oxygen ; if it contain more than about five-thousandths of foreign substances altogether ; or if, near these limits, it give bad results when subjected to the mechanical tests of hammering, rolling, and wire-drawing. It is also stated that tin offered should be rejected if, when run into elongated drops, it have not a smooth and re- flecting surface, without any considerable sign of rough spots ; if, when analyzed, it contain more than about one-thousandth of arsenic and antimony united ; more than about three- thousandths of lead or iron ; or more than four-thousandths of foreign substances. All bronze ought to be rejected which contains sulphur in an appreciable amount; which contains more than about one- thousandth of arsenic and antimony united; more than about three-thousandths of lead, iron, or zinc; or, in all, more than about five-thousandths of foreign substances. Notice should be taken of the appearance of the fracture of specimens ; it sometimes gives indications sufficient to authorize the rejection of certain bronzes full of sulphur or oxides. Gun-metal, when broken, should present a fine, close- grained fracture, of a uniform, beautiful golden color; it should be ductile, although finely granular and possibly crystalline. Bronze guns often exhibit, when burst, a decidedly crystal- line surface, the axes of the crystals lying radially to the bore. According, to the practice of the Navy Department, the bronze used for rifled howitzers is composed of Lake Superior copper 9 parts, tin I part. This 'is used when the casting is made in a sand mould. When a chill mould is used, which is the method now adopted for such castings, the proportion is changed to 10 to i. BRONZES AND OTHER COPPER-TIN ALLOYS. The copper is melted in a reverberatory furnace, and three hours after the fires are started, when the copper is in perfect fusion, the tin is stirred in ; half-an-hour after, the bronze is run off into the moulds. The casting cools nat- urally, and is taken out of the mould about twenty-four hours after the metal is run in. The chill mould is warmed suf- ficiently to drive out the moisture. 81. Phosphor-Bronze and Manganese Bronzes are alloys which are now so well known and have become so important in the arts as to demand special notice. PJiosphor bronze has been known many years. It consists simply of any alloy of bronze or brass or any ternary alloy of copper, tin and zinc which has been given exceptional purity and excellence by skilful fluxing with phosphorus. It is also supposed that the presence of phosphorus is useful in giving the tin a crystalline character which enables it to alloy itself more completely and strongly with the copper. Phosphor- .bronze will bear remelting with less injury than will common bronze. The phosphor bronzes greatly excel the unphos- phuretted alloy in every valuable commercial quality, and they are very extensively used for every purpose for which such alloys are fitted. The following are Kirkaldy's figures for tenacity and ductility of phosphor-bronze wire of No. 16 Birmingham gauge : PHOSPHOR-BRONZE WIRE, NO. 1 6, B. W. G. MATERIALS. LOAD AT FRACTURE. c.S o 'is J? No. twists be- G bo fore breaking. Unannealed. Annealed. .2 c Per sq. mm. Per sq . in. Per sq. mm. Per sq. in. Per cent. Unan- nealed. An- nealed. 72.3 kil. 46 T. 34. 7 kil. 22 T. 37 5 6. 7 80 Phosphor-bronze of several pro- - portions. 85.1 85.2 97-7 112. 2 54 54-1 62.1 71 2 33-6 37-5 42.8 41.7 21.3 23.8 27.2 26.5 34-1 42.4 44.9 46.6 22.3 13.0 17-3 13-3 52 124 106.3 67.6 45-4 28.9 42.8 15-0 60 144 MATERIALS OF ENGINEERING NON-FERROUS METALS. CAST PHOSPHOR-BRONZE. REDUCT. OF SEC- TION. ELASTIC LIMIT. ULTIMATE RESISTANCE. Per cent. Per. sq. mm. Per sq. in. Per sq. mm. Per sq. in. 8.4 i-5 33-4 16.05 kil- 17-38 II. 6 10.6 T. 11.05 7.2 37-0 32.5 3i-3 23- 5 T. 20. 6 19.9 The phosphorus is sometimes added to the alloy in the form of copper-phosphide, which is made by reducing acid phosphate with charcoal. This is added to the extent of from one and a half to three and a half per cent. Dry phos- phorus may be added in the crucible if preferred to phos- phor-tin or copper-phosphide. Phosphor-bronze was early known to chemists, but its valuable qualities as a material to be used in construction were first made known by MM. Montefiori, Levi, and Kun- zel, who discovered the alloy in the year 1871. According to Dick,* who introduced the alloy into the United States, the chemical action of phosphorus on the metals composing the alloy is two-fold : it reduces any oxides dissolved therein, and it forms with the purified metals a homogeneous and regular alloy, the hardness and the toughness of which are completely under control. We summarize, from the same source, the special uses of phosphor-bronze : I. It is very tough, and thus fitted for pis- ton rings and valve covers. 2. It is very tough and hard, and therefore used for machine castings, pinions, cog-wheels, pro- peller screws, hydraulic press and pump barrels, piston rods, screw bolts for steam cylinders, and hardware. 3. Very hard bronze is adopted for bearings of heated rolls, valves, etc. 4. Harder and stronger alloys than ordinary bell metal are employed for bells, steam -whistles, etc. 5. Acquiring great toughness, elasticity, and strength under the hammer, it is Journal Franklin Institute, 1878. BRONZES AND OTHER COPPER-TIN ALLOYS. 145 used for hammered piston-rods and bolts. 6. As bearing metal it is said to be better than the best gun-metal, very much less liable to heat than gun-metal, and when heated, it does not cut the journal. Ordnance has been made of this modification of gun- bronze by European nations, and has been found to excel in strength, toughness, and endurance. Small arms have also been made of it, and, in ship-work, the screws and sometimes rods in small vessels. When sheathing of this metal is used, it is found to possess exceptional power of resisting corro- sion. 82. Uses of Phosphor-Bronze. The comparatively high cost of phosphor-bronze has checked its introduction, not- withstanding its undeniable excellence. It is said to be stable, not losing much phosphorus by remelting, the tempera- ture of the fusion of the alloy being kept low, ranging from 752 to 932 Fahr. (400 to 500 C). Phosphor-tin is now sold in the market for use in making this bronze ; it is known by its number, as No. o, No. I. All alloys made with copper and phosphor-tin may be forged cold, provided the percentage of tin does not much exceed 12 per cent., and by this treatment they increase con- siderably in hardness. An alloy of 94 or 95 per cent, of cop- per, and 6 or 5 per cent, of phosphor-tin, may attain the hard- ness of ordnance steel, while the toughness of the bronze remains high. When expense does not permit the use of phosphor-bronze instead of ordinary bronze, the quality of the latter may be very materially improved by re-placing one-tenth of the percentage of tin by phosphor-tin, which carries enough phosphorus into the bronze to deoxidize the metals in the alloy, and the small increase in cost is coun- terbalanced by soundness of castings and improved working. It is best to avoid the use of zinc in making phosphor- bronze with phosphor-tin. Take, for heavy main-shaft jour- nals, 85 per cent, of copper and 15 per cent, of phosphor-tin, and for coupling and crank-rod journals, 90 per cent, of cop- per and 10 per cent, of phosphor-tin ; these alloys have great hardness and high tensile strength and toughness. 10 146 MATERIALS OF ENGINEERINGNON-FERROUS METALS. As a substitute for ordinary bronze take : , (35 parts of zinc, 30 parts of ^ood brass \ ~, . ( 65 parts of copper, 16 parts of copper, 4 parts of phosphor-tin, No. O. Gearing, tuyeres for blast-furnaces, and wire ropes of this alloy have been successfully used, the latter on the hoists of deep mines in Europe ; they have the advantages of great strength and freedom from corrosion. Phosphide of copper may be used in the manufacture of phosphor-bronze. It may be prepared by adding phosphorus to copper sulphide solution and boiling, adding sulphur as the sulphide is precipitated. The precipitate is carefully dried, melted, and cast into ingots. When of good quality and in proper condition, it is quite black. Phosphide of tin is oftener employed. When the precipi- tated tin obtained by the addition of zinc to a solution of chloride of tin (SnCl 2 ) is heated with phosphorus in the pro- portions of about nine atoms of tin to one of phosphorus, the phosphide (Sn g P) is produced. This compound resembles cast zinc, is crystalline, melts at about 370 C. (700 F.) and can be easily introduced into the crucible in the process of manufacture of bronze. " Phosphor-bronze " is, therefore, any copper-tin alloy or bronze which has been fluxed, in the process of making the alloy, by the addition of a measurable quantity of phosphorus. The metalloid maybe added either pure or combined, and either to the alloy itself or to one of its constituents, usually to the tin often as phosphate of copper, before mixing. A small quantity of phosphorus, chemically uniting with copper, hardens and strengthens it. Added in the process of manu- facture, in larger amount, it prevents the formation of copper, or other metal, oxide, and thus produces an alloy of such purity as to give greatly increased strength, and ductility as well, and also greater homogeneousness. In using phosphate of copper, Messrs. Ruoltz and de Fon- tenay mix the sirupy acid phosphate with 0.20 charcoal and BRONZES AND OTHER COPPER-TIN ALLOYS. 147 melt in plumbago crucibles, and use this material in the fol- lowing proportions,* the phosphate containing 9 per cent, phosphorus : In preparing phosphor-bronze it seems immaterial whether phosphor-copper or phosphor-tin is used, though the former is more likely to find an extended use, as it is applicable, not only for phosphor-bronze, but for other copper alloys contain- ing no tin, as yellow brass, German silver, etc., and for pure copper. It also possesses the advantage of being able to take up the greatest quantity of phosphorus, and consequently to offer the efficient reagent in the most compact form. In making phosphor-bronze or copper alloys of all sorts, the copper should first be melted in the usual way, with a cover of charcoal put over it as quickly as possible. After the required quantities of tin, zinc, etc., have been added, or in case of gun metal or brass scrap, after the latter has been completely melted, the small exactly weighed quantity of phosphor-copper is added while the metal is continually stirred. For stirring, a graphite bar, a strip cut from an old plumbago crucible, or a bar of retort carbon should be used. The stirring has to be done carefully, and the metal then freed of the coal and scoriae floating on the top ; it should be poured before the surface begins to be covered with a skin. The latter point and the careful stirring cannot be too urgently recommended. Phosphor-metals should always be covered with charcoal when remelted. A further addition of an extremely small quantity of phosphor-copper is necessary only in case the metal should not assume a bright mirror face. For preparing phosphor-bronze or remelting old gun metal and turnings, the addition of i^ Ib. to i^ Ib. of phosphor- copper of 15 per cent, phosphorus is generally sufficient fora hundred-weight of metal. In making or remelting brass, an addition of J^ to ^ part only is required per hundred. A larger percentage increases the hardness, but may lead to brittleness. The phosphor-copper of 15 per cent, phos- phorus itself is so brittle that the small ingots of about 2 Ib. * Lebasteur, p. 321. 148 MATERIALS OF ENGINEERING NON-FERROUS METALS. (I kg.) weight in which it is usually sold, can be broken in the hand by a light blow with a hammer into such pieces as are required. Sheathing metal made of phosphor-bronze is found to resist the action of sea-water remarkably well. In experi- ments made at Blankenbergh, lasting six months, comparing the best English copper and phosphor-bronze, the following results were arrived at : * LOSS OF THICKNESS OF THE SHEETS WEIGHT BE- WEIGHT 1 WEIGHT. 0.236 in. FORE IMMER- AFTFR TM_ = 0.6 cm. SION. MERSION. Actual. Per cent. Sheet of copper 7d. A. 72 2 2 2 3 QTC Do. 88 Q 86 2 27 3 TOO Sheet of phosphor-bronze .... 695 68.75 0.75 I.I23 Do. Do II4-3 112.97 i-33 I.I95 The loss in weight, therefore, due to the oxidizing action of sea-water during the six months' trial, averaged for the English "copper 3.058 per cent., while that of the phosphor- bronze was but 1.158 per cent. According to Delalot,f true phosphor-bronze is not an alloy; it is a combination of copper with phosphorus; it is simply a phosphide of copper in definite proportions. The metal unites with the metalloid either cold or hot ; for some applications of phosphor-bronze the cold method suffices. Phosphor-bronze made by the hot process does not allow the introduction of simple bodies other than the metal and the metalloid. Copper exempt from arsenic, antimony, iron, or zinc, is required ; it must be commercially pure. The manu- facturer may choose from three kinds of phosphorus, ordinary, amorphous, and all the earthy biphosphates. Amorphous phosphorus is the most expensive, but the best. The secret of making good phosphor-bronze lies in the working of .the * M. J. Maure, Engineering, Sect. T2 ; 1873. f Moniteur Industrielle Beige ; 1878. v BRONZES AND OTHER COPPER-TIN ALLOYS. 149 furnace and in practice. The following are the best combina- tions in definite proportions. The minimum and maximum percentages of phosphorus in phosphor-bronze are 2 and 4. Five sorts of phosphor-bronze, however, are considered to answer all requirements. 0. Ordinary phosphor-bronze of 2 per cent, of phosphorus. 1. Good " " " 2% These two numbers are superior to ordinary bronze and steel in all cases. 2. Superior phosphor-bronze of 3 per cent, of phosphorus. 3. Extra " " " 3j 4. Maximum " " " 4 " These three, according to Delalot, are superior to any other bronzes. Above No. 4, phosphor-bronze is useless ; below o, it is inferior to common bronze and steel. The price of phosphor-bronze unworked, for all numbers, should not exceed that of copper by over ten per cent. Nos. 3 and 4 are comparatively unoxidizable. It is stated by Dumas that the characteristics of these alloys change with the addition of phosphorus. The color, when the proportion of phosphorus exceeds ^ per cent, becomes warmer, and like that of gold largely alloyed with copper. The grain and fracture approximate to those of steel. The elasticity is considerably increased, the tenacity also becomes in some cases more than doubled ; the density is also in- creased, and to such a degree that some phosphor-bronzes are with difficulty touched by the file. The metal, when cast, has great fluidity, and fills the mo'uld perfectly, exhibit- ing the smallest details. By varying the doses of phosphorus and tin, the particular characteristic of the alloy which is most desired can be varied at pleasure. 83. Tabular Exhibit of Properties of the Copper-Tin Alloys.* The following table is a list of about 140 different alloys of copper and tin, giving some of their mechanical and physical properties. . ^ __ * Prepared originally for the U. S. Board ; Committee on Alloys' Report, vol. i., 1878, p. 389. ISO MATERIALS OF ENGINEERING NON-FERROUS METALS. 1 v-i ^ tx cx "2. 8 >" III 1 Ij 1 , .iff 1 8.8,3 "s y^s^^o Ss^s-Grt C/3C/5*- 1 toaj rt t3 *3 001 =J9A -jis 'A)pu}33[3 001 = J3A[IS '}B3q joj AjiAiphpiKT) '(1 3 H B K) i : ::^i 1 ! i : : : : S M . . . VO (}3[IBJ^) All -jiqBsiiBin jo japJQ (uosuqof PUB JJ3A[B3 pUB (uojsanqx) Xji[ipnp 3Ai}B[3-a oc C 2 is : 1 i : : ! i i : i : : : ' ' ... . . . . ro ... i 8 . ' 2. : : : Ajinionp jo J3pjQ X c o qoui 3JBnbs jad spunod 'XjioBuax & t 10 N m | 1 b 42 -43 S : 3 ; ; 3 3 u ; <> ; u o W :>::>> : : U 1 ^3 : : : 15 !! ? i IS, Js ! 00 > Y 0000 00 00 00 -00 -00 -00 0000 00 8^' ^ U* 1 rt c3 : i i i i i i i : i : i i ^ : : : iiis ^ ~i 8"888888^^8g>l? K8 8 8>8 8 J-=ti 3 88888888S23"89>t> Sr8 828 "o Si 8 ISM?**** 8 * ** s - ss a Bjnuuoj oiuiojy ; . ; 3 .... 3 . . ; ; u u '.'.'.''.'.'.'. :^n '.'.'.'. c/: I : ; . J3 qinn N BRONZES AND OTHER COPPER-TIN ALLOYS. .. - M (6 41 U . "O C !isijJ.j ^il 11 SI III sill! 111 Il3 KttWOci HfcOfe U < sion. Railroad-car bearings. Ordnance-metal. Small bar cast in iron mould. Small bar cast in clav 'j ! ll B J-. M I'sl 1 Ills |g| 1 ^2l COu W3 W JC SO S ^_Q (Riche). Axle-bearincr Seraine lo- i i 'i .ma ^ ^ ""^/ic/jea"^' (riffled -cd sffl'cdfflc/i U DD U ^ ID 1 .:.... d 00 S ::::::$:::::: ! : 1: :|| : H :j : ; M :S-8 :::::: : ! : : :>8 : i : 1 i 5:::f :<8 5- : : : : : : : Z : : :*8 : : : R Cl N . . . N . . . CO . M = 8 :::::::::: :^ CJ i ii;;ii;i;|i 1 : : :fr y i i ig it i ! i ; ; !; i i ; il :| : i M i Ml : :::::::: :^ :-^- -fe I 1 '." . > : : : 1 * " * *3 *S . . ... . u n ^ : : :-g :^ : : : : : : : : : : ' : : ^ !H !8"!! il 4 j| > m < Ov < ?S ^-J?? : :4- : oo ? t ^ coco oooom --\o-voOxoc oo oo m 000000 ; 00 ; -00 oo a CO CO OOOOOO CO CO CO OC 00 0000 :::::::::::::: 8s I 882. f : :::::::: j j N C>>C \O ts. \o >. c^co oooooo'oooo'oooox^d^d C ) C C ) OOO"- l N M P * iMO "TO M M * > S'oS S>8 tt ?. ??>3.8NK2 8 3 883. < r S 1 S" J? 8 ao? 3 8 S>o9 ^ p.?"^? S^3>^^3,S.3,3>5,aaaS.8s i 8*8^ 0= r ^^cg'^sssScS-^s s s ! cS UCQ <<< 001 == J3ATIS '}B3t{ aoj AiiAijon (uosuqof qoui ajunbs J9d spunod 'Xj ^iABjS ogpadg u ~ o S h yel. sh gr 'wish red CO co oo oo oo oo CT, . ro o o . rtj &8 6 .(/) fcl Tj- is* o 'S tv o O\ t^ 00 CO 00 CO CO CO gra Pi l-^ 10 O ^ O in w vo H 10^^ > i^ r^\o Oirj^t^ 1 - 1 'Oocoo 888 5 1 8 8,8 P. QOQ 000 rOi'O NOO>3- ) CO l-^O \O >O O IT) ; c : -C/3 uu 155 : [333 \ : . : 33 C/)C/3 -C/3C/3! K8 JS eg BRONZES AND OTHER COPPER-TIN ALLOYS. 153 II | 4 I 1 2* =3 I I I I I & > .c3 . w 'c/j J3 D CSCQW m'd o'cda cdca : : : !?: : ::: : : : : : : : n a ^-j-j 4^ 8 : O O - H iff ^^- fl s . 8 : :5 ' 6 6 : o' o o o o' o' o' 6 o' 000 o* | o' o : : : o ; o jo . o SH H Jo : 3 N^to i f:K : g|s a o o o J8 M *O C*l OVOIO M M M . M N M H HI M . N ro . M N COM fO N M COCO . cT 111 31 a ^ o > to o !| ! C ,- 3 -.ii.. ggg S o : '. u & =3 I s3 y jg& l 1 - ^ to v, * u_5 'U urtu ou u : P4 O *rt j> E rt ~ t^ S s.^ 5 a g Bluish red Reddish wh White ^ (/) <5 White Steel gra> Bluish gra Dark gra; 2 2 to tx Q Q Light gra Light gra Grayish wh Bluish whi Grayish wh JZ1 1 .22 | i ! o f & l O O 1O 10 N -, : |1 v O* ^ ; t^ T i o o r^ co "tlvovo" v - , ^ 5 w !5- K*!$ oH oo o ^ ! -5^-5? 00 CO CO a X 00 00 . OO OO OC M 00 OO CO CO 00 OC OC -^ CO OO OO OC 00 00 00 oo oo a t a 00 CO ' tx CO CO ' ' : : c? ?> : ; ; S : : : ? : 5- : : So : 10 >0 vS : g : : : :S : : : : v2 : . t- Tf f) oo 8 : : : ^- . . . . .& .NO - S, .^ : Erg 8 8 ffRRSS^ 8o 8 iO t^OO OOOO ro ro (*i m m NfO^ OO .OOOOOOOONNlOtO t^OO O O N 10 10 * V * -^-.^^THOIOIOIOIOIOIO 10^6 V3 vo vo g S. g. R.S S S oT o?co tC i ; 8 S IONO'O' 10 r. 8 P 10 OM> j ; M H M* o* o* ti tC *<* >-' o' <> t>. * * 10 >O 10 10 10 * -^ * -^- * * f rr, er, ft) ff, M O - CO>0 S . . .3333 . U ' ' UUUU ' 1 j J5- i : < : :c i ^^ iic-i . -t/: c/3 c/5 c/5 c/5 c/3 c/i ( 3i;5: 133333 . -C/) 'c/3 -t 154 MATERIALS OF ENGINEERING NON-FERROUS METALS. PROPERTIES OF ALLOYS OF COPPER AND TIN. Remarks. 1 ? L i ii . j 001 = ipny 43A ^ da ^^^^^ -JIS 'XjpUJD3p 001 = J3A[|S joj AjiAip'n U3UBJM puo3 ) M H ... . m . . vo . . . vo ' iO *'*' fO ' A}i[iqisnj jo aspJQ (}3tlBJ\[) A}t -lfqB3[[BUJjoa3pao : : : ; ; ; 1/5 ; ; ; * ; PUB U3A[B3 PUB 'J3J[B]/^) SS3UpJBfJ ro - H : H '. c (N . . ^00 : " (uojsjnqx) S3 : S* S : ^8 : 8 : g, : p. 8 : : : : 00-00 ... o ; >* . ilij ro Aiitrpnp jo 43pJQ qoui sjsnbs J3d spunbd 'AjpBusj, H:K8 t^ O r~ o 1 ^:5: ro vo' ro N ^ .vo m TTCO, vo'vo" ro VO .VO . i * Crystal Fine cryst. Crystal Coarse cryst. to i : ^L- ' ^.^ C <*> ^ ; cj |gcj o Crystal Coarse cryst. Granular Earthy 1 V V "> 15 " ? ^ ? -a u o o ' 1H ri Grayish white Grayish white , S o"c3 o-- c U rt 3 IHI! i :^:: . . ra . . . (>. . . . .. vo * -oo" -co ON 00 HI A 'S Si 8 vo Sj^N S K^o 00* ro 2>v8 S KoS -^ S> ?"2 "S *S ?T ^ ro ro ^ N IT) IT) t^co COOOOOCO N W rO^-'^'*f < ^- t^OO OOCOOOOOOOO fx tv. t< t^ t^ ti. t^ t^ I-s t>.00 00 00 CO 00 00 00 00 CO 00 CO 00 OX ON ON 6 MOOOOO-* H-OO moo O M - O-t^Ovo ** roroooo o t^iooroi/it^ MMMHVOIO^MCIKH oco oo oo oo t^ r^ t^vo O Bjnuuoj oiuioiv 3 ' '3 . 333 3' 3 . .33 3' 3 .3333 3' 3 33 u -u uuuuu -.ucjcju -uuuuuuuu c : :c : GCCGC : :c"ccc :cccccccc CO CO COCOCOCOCO -COCOCOCO CO 00 CO CO CO V) CO CO aaqamw rorSSS^ro ^gi^^^^^^^^^-^^toJoSSlo^^^ BRONZES AND OTHER COPPER-TIN ALLOYS. 155 m t^co O^OO 00000 o\ o\ o a o c a uu OF THE MATERIALS OF ENGINEERING NON-FERROUS METALS. In the above table the figures or order of ductility, malle- ability, hardness, and fusibility are taken from Mallet's experi- ments on a series of sixteen alloys, the figure I representing the maximum and 16 the minimum of the property. The ductility of the brittle metals is represented by Mallet as o. The relative ductility given in the table of the alloys ex- perimented on by the U. S. Board, is the proportionate exten- sion of the exterior fibres of the pieces tested by torsion as determined by the autographic strain-diagrams. It will be seen that the order of ductility differs widely from that given by Mallet. The figures of relative hardness, on the authority of Cal- vert and Johnson, are those obtained by them by means of an indenting tool. The figures are on a scale in which cast iron is rated at 1,000. The word "broke" in this column indi- cates the fact that the alloy opposite which it occurs broke under the indenting tool, showing that the relative hardness could not be measured, but was considerably greater than that of cast iron. The quality of the iron is not specified. The figures of specific gravity show a fair agreement among the several authorities for the alloys containing more than 35 per cent, of tin, except those given by Mallet, which are in general very much lower than those by all the other authorities. In the alloys containing less than 35 per cent, of tin there is a wide variation among all the different authori- ties ; Mallet's figures, however, being generally lower than the others. Several of the figures of specific gravity have been selected from Riche's results of experiments on the effects of annealing, tempering, and compression, which show that the latter especially tends to increase the specific gravity of all the alloys containing less than 20 per cent, tin to about 8.92. This result, as stated in the discussion on specific gravity above, is due merely to the closing up of the blow-holes, and thus diminishing the porosity. The specific gravity of 8.953 was obtained by Major Wade by casting a small bar in a cold iron mould from the same metal which gave a specific gravity of only 8.313 when cast in the form of a small bar in a clay mould. The former result is exceptionally high, and in- BRONZES AND OTHER COPPER-TIN ALLOYS. Itf dicates the probability that every circumstance of the melt- ing, pouring, casting, and cooling was favorable to the ex- clusion of the gas which forms blow-holes, and to the forma- tion of a perfectly compact metal. The figures of tenacity given by Mallet, Muschenbroek, and Wade agree with those found in the experiments de- scribed in this volume as closely as could be expected from the very variable strengths of alloys of the same composition which have been found by all experimenters. Mallet's figure for copper, 24.6 tons, or 55,104 pounds, is probably much too high for cast copper; the piece which he tested was probably rolled or perhaps drawn into wire. Has- w ell's Pocket Book gives the following as the tensile strength of copper ; the names of the authorities are not given : Pounds per square inch. Copper, wrought 34>ooo Copper, rolled 36,000 Copper, cast (American) 24,250 Copper, wire 61,200 Copper, bolt 36,800 This table of comparison of authorities is by no means complete. No account is taken of a vast number of ancient bronzes, weapons, medals, coins, and sonorous instruments which have been described by various writers. These, how- ever, differ but little in composition and properties from the ordnance and bell metal given in the tables. It will be observed that while there is considerable irregu- larity in the tenacity of the alloys containing more than 27.5 per cent, of tin, they are all extremely weak, the highest strength found by any experimenter being only 8,736 pounds, and valueless for all purposes in which strength is required. It has been shown that the useful alloys, those which con- tain less than 27.5 per cent, of tin, have strengths which are nearly proportional to their densities. CHAPTER V. THE BRASSES AND OTHER COPPER-ZINC ALLOYS. 84. Brass is a term which is applied by many, and espe- cially older, authors indifferently to all alloys composed princi- pally of copper, combined with either tin or zinc. The alloy of copper and tin and its minor modifications are now becom- ing better known as bronze, and the name brass is generally restricted to the designation of alloys consisting mainly of copper and zinc. " Brass " ordnance is properly called bronze ordnance, and the compositions used in the bearings of machinery, which are usually of somewhat similar compo- sition, are also properly called bronzes. The alloys of copper, tin and zinc, which occupy intermediate positions between the bronzes and the brasses, are as often known by the one name as by the other. 85. Copper and Zinc together form " Brass," which is usu- ally made nearly in the proportion, copper, 66^3, zinc 33/^ Brasses of certain other proportions have specific names, as Tourbac, Pinchbeck. The mixture and fusion of the metals must be so conducted that the loss of zinc by volatilization may be the least possible ; there is always some loss, and it may not only be serious as a matter of cost, but the introduc- tion of oxides into the alloy is exceedingly injurious to its quality. The fusion is generally performed in crucibles heated in air-furnaces. The change of color and of other qualities with the intro- duction of zinc is gradual and very similar in character to that produced by the admixture of tin ; but the quantity of zinc demanded to produce the same modification is about twice as much as of tin. On adding zinc, the deep red color of copper is changed at once, becoming lighter and lighter, BRASSES AND OTHER COPPER-ZINC ALLOYS. 159 and finally shading into a grayish white and then assuming more of the color of zinc. The alloy generally increases in hardness and loses ductility as the percentage of zinc is in- creased, up to a maximum, which being passed, ductility increases again. The most ductile are, however, those which contain 70 to 85 per cent, copper, 30 to 15 of zinc, the first being called "tombac," the latter "brass." 86. Mallet's Classification. The following is Mallet's table of the copper-zinc alloys : TABLE XXI. PROPERTIES OF COPPER-ZINC ALLOYS. ORDI IR OF AT- COM P. COPPKR S. G. COLOR* FRACT. TENACITY. Mall. Hard. Fus. by anal. Cu Zn i per ct. IOO. 8.667 red Tons per sq. in. 24.6 g 22 10 98.80 8.605 red -yellow coarse 12.1 6 21 J 5 J 4 9 90.72 8.607 vi fine "5 4 20 13 8 88.60 8.633 it u 12.8 2 19 12 I 87.30 85.40 *S9 yellow-red ii fine fibre 13-2 n. i 5 18 17 ii IO 5 83.02 8.4J5 " 13-7 IT 16 4 3 79-65 74-58 8.448 8-397 pale yellow 14.7 i3-i 7 10 15 14 7 a 66.18 8.299 deep ' 12.5 3 23 6 i 49-47 8.230 " " coarse 9.2 12 12 6 i 32-85 8.263 dark " 19-3 I 10 6 ! i 31-52 30-3 6 7.721 7.836 silver white silver white 2.1 2.2 very brittle I 5 5 ! 2 29.17 28.12 7.019 light gray ash ' vitreous 0.7 3-2 brittle 7 3 5 5 8 21 8 22 27.10 26.24 7.'882 light ; coarse 0. 9 0.8 u 9 i 5 5 8 23 25-39 7-443 ash ' fine 5-9 slight duct. i 5 1 3 24.50 7-449 it * ** 3.i brittle 2 4 * 4 19.65 7-371 44 1.9 4 3 i 5 O I 16.36 O. 6.605 6 801; dark ' 1.8 15.2 ii 27 2 I u *Vj J In the above table, the minimum of hardness and fusibility is denoted by i. The conclusion of Storer* that these alloys are mixtures rather than true compounds, is accepted by Watts and other authorities. 87. Uses of Brass. Brass is the alloy commonly em- ployed in the arts in the construction of scientific apparatus, * Mem. Am. Acad., N. S., vol. viii, p. 97. l6o MATERIALS OF ENGINEERING NON-FERROUS METALS. mathematical instruments, and small parts of machinery. It is cast into parts of irregular shape, drawn into wire, or rolled into rods and sheets. It is harder than copper, very malle- able and ductile, and can be " struck up " in dies, formed in moulds, or " spun " into vessels of a wide variety of forms if handled cold or slightly warm ; it is brittle at a high tempera- ture. A common proportion for making brass is copper 66, zinc 34. This alloy is a much slower conductor of electricity and of heat than copper, is more fusible, oxidizes very slowly at low temperatures, but rapidly at a high heat. The brass of Romilly, which works remarkably well under the hammer, is composed of copper 70, zinc 30 ; English brass is often given 33 per cent, zinc, and for rolled brass 40 per cent. This constitutes " Muntz sheathing metal," as patented by G. F. Muntz in 1832. The proportion of zinc ranges, however, for such purposes, from 37 to 50 per cent, copper 63 to 50* 88. Muntz Metal is thus described by its inventor : " I take that quality of copper known in the trade by the ap- pellation of * best selected copper,' and that quality of zinc, known in England as ' foreign zinc/ and melt them together in the usual manner in any proportion between 50 per cent, of copper to 50 per cent, of zinc, and 63 per cent, of copper to 37 per cent, of zinc, both of which extremes, and all intermediate proportions, will roll and work at a red heat ; but as too large a proportion of copper increases the diffi- culty of working the metal, and too large a proportion of zinc renders the metal too hard when cold, I prefer the alloy to consist of about 60 per cent, of copper to 40 per cent, of zinc. This compound I cast into ingots of any con- venient weight, and then heat them to a red heat, and roll or work them while at that heat into bolts and other like ship's fastenings, in the same manner as copper is rolled or worked, but only taking care not to overheat the metal so as to pro- duce fusion, and not to put it through the rolls or work it after the heat has left it too much, say, when the red heat goes off." This alloy is cast into ingots, and rolled, hot, into sheets, BRA SSES A ND O THER COPPER-ZINC ALLO YS. 1 6 1 which are cleaned by pickling and washed before they are sent into the market. As this alloy is cheaper and more du- rable than copper sheathing, and equally effective, it has dis- placed the latter almost entirely in the protection of wooden ships. When made on a large scale, the alloy is melted in a reverberatory furnace. 89. Special Properties. Farmer has deposited brass by electrolysis and obtained an alloy containing copper 75, zinc 25, as ductile and malleable as rolled brass. The brasses, or copper-zinc alloys, although probably of more extended use than the bronzes or copper-tin alloys, are not as well studied as the latter. The metals, as already stated ( 85), mix in all propor- tions, and produce alloys of which the general character has been shown in the introductory chapter of this part of the work and in the earlier paragraphs of this chapter. The red color of copper, in this series, fades into yellow very gradually, and becomes golden-yellow at about 40 per cent, zinc ; the color then becomes lighter, and at 60 per cent, zinc is bluish-white or silvery. With the change of color occurs the same change of strength and ductility noted with the copper-tin alloys, but it requires about twice as much zinc as tin to produce it. The white metals richest in copper are, like those of the bronze class, too brittle to be of use in engineering construction, but the yellow metals ob- tained with from 40 to 50 per cent, zinc are very valuable. Brass has a high coefficient of expansion, 0.000054 to 0.000056 per Cent, degree (0.00003 to 0.000033 per degree F.).* Yellow brass fuses at from 1,870 F. (1,021 C), and other compositions from 1,000 F. (550 C., nearly) to 2,000 F. (1,100 C, nearly), and loses strength and ductility as its tem- perature rises. The composition of the several most useful brasses is given elsewhere. Brass for fine work is often made of copper, 80; zinc, 17; tin, 3 ; "fine brass" of 2 copper, I of zinc ; sheet brass of 3 copper, I zinc. A hard solder is made of 3 parts brass to I of zinc, etc., etc. Castings shrink in cooling T \ inch to the foot (0.015). * Vide Chapter I. II 1 62 MATERIALS OF ENGINEERING NON-FERROUS METALS. Hydrochloric acid reddens brass by dissolving its zinc; ammonia whitens it by taking up the copper. Brass may be made tough and soft, hard and brittle, strong or weak, elastic or inelastic, dull of surface or lustrous as a mirror, friable or nearly as malleable and ductile as lead, as may be desired, by varying its composition. No known ma- terial, perhaps not even excepting iron, can be given so wide a range of quality or so wonderful a variety of uses. All the common varieties are composed of 67 to 70 parts copper and 33 to 30 of zinc. A little lead is often added to soften and cheapen it and tin in small proportion to strengthen it. Brass is subject to flow under stress, like all other metals of what the Author has called the " tin class," and it is not safe to leave heavy loads upon it. Weights should not usually be hung upon brass chains, or upon brass tie-rods. The alloy is capable of being considerably hardened by compression, as when rolled into sheets, or by wire-drawing, and becomes much stronger and is less liable to permanent change under load. Some compositions are very elastic and make good springs for intermittent and occasional use. The thin sheet brass used for metallic cartridges and other purposes requiring a metal in this form of great strength combined with ductility, is subject, frequently, to a singular deterioration with age which seem to be partly a physical and partly a chemical change. It results, sometimes in a very brief interval, in the entire destruction of the essential proper- ties of such forms of this alloy. This has been studied by Egleston, but the results of irvestigation are not yet fully known. Weems has found '* that a pressure of 4,000 tons (or ton- nes) being applied to brass, in the endeavor to produce brass tubes by " squirting " as is usual with lead, causes a separa- tion of the zinc, which issues as a zinc pipe, leaving the cop- per behind. This is considered a proof that this alloy is a mixture rather than a chemical compound. 90. Applications in the Arts. Bronze and brass have in- numerable uses in the arts : locks, keys, shields, escutcheons, * Land. Engineer, 1883. BRASSES AND OTHER COPPER-ZINC ALLOTS. 163 hinges, journal-bearings, pump-plungers, screw propellers, all small parts of machinery, optical and other philosophical instruments, cabinet-makers' fittings, sheathing of ships. Even so-called copper castings usually contain a small amount of zinc 2 to 5 per cent., to give them soundness. The copper and brass manufactures of the United States are very extensive and of excellent character, both as to ma- terial and workmanship, and in those departments which are purely mechanical, are probably unequalled elsewhere. The purest copper is at their doors and the best of zinc ; while tin is likely, in time, to be largely produced in this country also. Brass to be used in the rolling mill in the manufacture of sheet metal, is cast between marble blocks which are separ- ated to a distance which determines the thickness of the ingot or slab. The marble is coated with a thin layer of loam prepared for the purpose; the sides are closed with moulding sand. The slabs, when cast, are rolled, several " passes" being necessary, and the sheets are annealed at intervals, and when finally finished are " pickled " to give them a good surface. For fine work, the surfaces must sometimes be repeatedly scraped during the process of rolling to remove surface impurities and defects. Wire brass is similarly treated, and the plates are then slit into rods in the " slitting mill," rolled to give them a section which can be handled in the wire-mill, and the rods are then drawn as in making iron wire.* Brass tubes for steam boilers, condensers and other pur- poses, are usually drawn, as are many other forms of section. 91. Working Brass. Yellow brass, and several composi- tions of similar character, are so easily worked cold that many articles are made by "striking up" in a die, under a press or a drop-hammer. Where a considerable change of form is necessary, the work is done by a succession of opera- tions alternating with annealing. Rolls may often be used to form brass into the desired shape and they are still oftener employed to impress a pattern on the sheet. * Part I, 138, p. 196. 164 MATERIALS CF ENGINEERING NON-FERROUS METALS. " Spinning " is a peculiar and very interesting, as well as useful process. It is employed in altering the shape of a disk or of a cylinder which can be " chucked " and held in a lathe, while the tool of the workman, pressing on the edge, turns it over and forces it into a new shape. Spinning brass often consists merely in forming a flat sheet, turning in the lathe, by the pressure of a smooth burnishing tool. Chasing is done with a graver, and matting and emboss- ing with formers and hammers. In burnishing to give high lustre, the metal is kept wet with sour beer, while the burnisher by a steady friction produces the polish. " Burnishing " consists in giving a fine lustrous surface by the pressure and friction of a smooth, highly polished steel tool, lubricated well, as above. The surface is first prepared by giving it a good polish by the usual methods. The "burnishers" are made of fine steel, carefully polished with crocus and oil, and kept in the most perfect possible con- dition. The working of brass in the lathe requires especial care, not only in the handling, but also in the form of the tool. The cutting edge is given a much larger angle than in cutting iron and steel ; hand-tools require to be given precisely the right inclination and a constant rotation ; the velocity of cutting greatly exceeds that usual with iron. Brass tubes are sometimes made by simply rolling sheet- brass, cut to exact size, upon a mandrel and brazing or solder- ing the joint ; but they are more usually " drawn." The roll and its mandrel are sent through the draw-plate together and the tube is thus drawn to size and the soldered lap becomes distinguishable only by the color of the joint. Locomotive tubes, and others required to bear very high temperatures and pressures, are drawn solid and seamless. Brass condenser tubes should be made of copper 70, zinc 30, as prescribed by the British Admiralty. Boiler tubes are made of copper 18, zinc 32. The metals should be pure. In many cases peculiar and ornamental shapes are given by modification of the form of mandrel or of draw-plates. Patterned sheets are produced by the use of rolls with BRASSES AND OTHER COPPER-ZINC ALLOYS. 165 properly cut surfaces. The " die" in which the metal is given shape under the blows of a " drop," or of a heavy hammer, is very extensively used in working brass. 92. The Properties of Brasses, as described by the best authorities, are exhibited in the most concise manner in the following table, which was originally collated for the Com- mittee on Alloys of the U. S. Board,* as was that already given for the bronzes. It includes the results of work done for that board. A more complete exhibit of the mechanical properties of the bronzes and brasses will be given in succeeding chapters describing investigations, usually conducted by the Author, as above. * Report, vol. ii, 1881, p. 67. 1.66 MATERIALS OF ENGINEERING-NON-FERROUS METALS. Xjuoqjnv 031 =43AJIS *J ooi = J3AJIS '}T23q joj AjiArpnpuoj . 'S C^ i 1 mm :D & (uosuqof JJ9AIB3 pUB tpui arenbs aad spunod ' AjiAEjS ogpsdg 111 u Fibrous Earthy . : OO 00* Vesicu Vesicu CO OO ON - OO f* -vo se c sicu :v8^ J^oo ?> S \o in 10 Ot^t^ ^ lOfONN &oo o- Q~&o\a\ 5 5 BRASSES AND OTHER COPPER-ZINC ALLOYS. 167 4 * i 8*. I I ft i 2oS tfr O -| . | sag *i ^LJg * 3 ^ o^3 u a u - si-g t* .2-3 se ilfl! ** w i II * .s . .o" . .cd .^ .od .n . . .cd . . . . .a U ^ 03 . . o . . f* e* O . .vO . .VO O : :S: :Sa o CO " ilU Ml! : : i miinimjiiiiiMUH ^ i iS^i :5 : 11 ^ OO -CO 8 : : 5 : S : :S> : ' : :R g i :s : ,: ij: 8 : : ,S^ S??5-., %5- ErjfErSggSSS^y^S 1 s-s^S'ss 1 ; ro VO O O O* w OOCOOOOOOOOC OOOOOOOOOOOOOOOOf 33 NNN 555 1 68 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XXII. Continued. & 1 i J. f j>* i i 1 ifi K f 'Sou t> Sfl* o "Sfi b'oJ3 ^w" !l\- ! fc-a! -a-s 1! 1 i '2-S < i' >S 'o^-S w"^ a -2 "3 s ^o^lM u 8 6^ 6^ o^ u t> c l^il S s 11 il 41 1 K i Sp. gr. of ingot, 8.263. Escutcheons of locks. Sp. gr. of ingot, 8.039. Ic^f Ajuoipnv 001 = J3A -jis k A}pu}03[3 001 = J3AIIS '}B3l{ joj XjiAijohpuoj . .03 . .03 . . .03 j . .03 .03 . .PQ03 . . '_ 03 CQ 03 CQ CQ j&v^W^^W^U | n (uosuqof PUB JJ3AIB3 pUB '13IIBJ\[) ssaupjBjj (}3l[BJ^[) Xjl (uoisjnqj,) A^I[i:pnp 3AIJBI3"JJ (jailBp^) :::::::::: M ^ i- . . . vo vr> : : Os . . M O> t^ CO . o o 00 Xjitponp jo japJQ iput ajBnbs jad spunbd 'A^pBuaj, 8 X ' ' . . . o .0 . o o oo |ft 1? ? . 00 CO oo" . O I "* ; ...-*;. N. . * q;^ ; 1 in ; T- ; * ro o I ^ : 1 U 2s :..>:>>: t C* : : :-S :-S : > y i 1 r g i|" il Finely gran. Vitreous conch Vitreous conch :W : ; i ; w ; w i | : : : : : , u g * ft : ^ ! ! U i^ & ^ Pinkish gray Pinkish gray Silver white Silver white =1 : "p 1 : : :"3 :"w :"3 "3 . ^* . t> . ^%^ >^ * 'O X^iABjS otjioadg o <* ig; j JH o o^S-is 00 00 OO 00 00 OO -OO -00 00 00 OO t^OO CO OOCX5CX3 r*^ lit U rt A Is :S> : :^ ' : S : 2 : $ : *8. ? : : & <8 '.% '. : :5- :? : ?0> : :S,S>So ^^vSvS 3' CJ : N : : $ : : :::::$: t? : 88 : : : s;^ : : : :vg : : : : ^ : ffi : 3? : : :~ ^ Composi- tion of original mixture. N 'OsOOOOO'-N^OiO r)\O t^-OOOO Nirt^f^OQNfO 3 CJ ^ * fO >0 in C?00 Lji!&mSxiu!$&99?S || NN ,SSr5 N N CN ^ NJ c^ 33 3 D 3 33 UU UUU U 'J BRASSES AND OTHER COPPER-ZINC ALLOYS. 169 1 = - - o- o i f :- c > > II I > iZ & 5 5 c=3 ** * & jig ^ * . AS 3 ^ o n & 1= ta iti-r 1 as & 1 6 | 3 0.5 b'C 'C S rt 'C g d 'C d. u 0^ t/5 > >P3 >PkC3 03 S^ c O c/5 03 . LIST OF AUTHORITIES. Bo. Bolley. Essais et rccherches chimiques, Paris, 1869. Cr. Croockewit. Erdmann's Journal, xlv., 1848. pp. 87-93. C. J. Calvert and Johnson. Phil. Ma%., 18. 1850. pp. 3^4-359; ibid., 17, 1859, pp. 114-121 : ibid., 16, 1858, pp. 381-383. Ma.-Matthiessen. Phil. Trans., 1860. pp. 161-184 ; ibid., 1864, pp. 167-200. Ml. Mallet. Phil. Mag., v. 21, 1842, pp. 66-68. Ri. Riche. Annales de chimie, 30, 1873, pp. 751-410. U. S. B. Report of Committee on Metallic Alloys of United States Board appointed to test iron, steel, etc. (Thurston's Investigations). We. Weidemann. Pogg. Annalcn, 108, 1859, pp. 393-407. . ffl . .03 . .03 . . . .03* . .C3S ... 03 .CQm 03 0303" C3 03' P P P P ^P P PP PDPPP O 2 ""'^ ^ m ' O* 00 u i . . . . O i w :::oo oo^oo I O o O 8 : :8^ : o ' 000 MVO .; N r^ TI-OO ^oo oo -*^o a M M' t^ O ft o w " o m m m . o M ir> invo O O ^* I M 11 PH W C*> " *J *U ^^ "u ^- ' C rt C rt w ^ b 813 3| | 2 11 1* 11* r J |5| u > 6 Finely cryst. Finely gran. Finely cryst. Finely gran. Finely cryst. Finely gran. Finely cryst. Finely gran. Finely gran. Finely cryst. Tab. cryst. i' 3 ' lili* 1 Ash gray Bluish gray Ash gray if If C ;03 Bluish gray tt Bluish white Bluish gray ^H^^SvSt^i ONVO OO 1 * - w - ^^gl^O?? . t^ t>. t^ ^ t>.0 tx . : : ? f? : : D" : : : : '%'& Si>o : ' 2vo"8 co O >n < : :^> : :S : : : : r^ t^ as : :^Sc? oo OM7- O : : : :S : : ^ : : :::::: : :::>;: :4ci ro M m ) mvo ^ oo O moo O O M \o m moo ^ O oo >Mcimm-*tx coooinON t^>O vo m in in m * * mvo r- n M a^8 S ! j \o"o*o - \o'vo <8*?.?.r^S.ri.KS^^t^IC t^oo oo o? oo oo oo o?o?oo 1 oo"oc ^rtomSfim ^2in2jT^m "3>m vo'InJn m'm ?o moo n -^ - RftS.AS.A^ &^ SS^JSS S 8 ?? ff^'S'S ?2 2 2 ^ 533 S 33 3*5" 3" 33 333 33 d MATERIALS OF ENGINEERING NON-FERROUS METALS. Note on the Table. Alloys having the name of Bol- ley appended, are taken from Bolley's " Essais et Recherches Chimiques," which gives compositions and commercial names, and mentions valuable properties, such as are given in the columns of remarks, but does not give results in figures, as recorded by other authorities. The same properties and the same name are accorded by Bolley to alloys of different com- positions, such as those which in the column of remarks are said to be " suitable for forging." It might be supposed that such properties belonged to those mixtures and not to other mixtures of similar composition. It seems probable, how- ever, that v/hen two alloys of different mixtures of copper and zinc are found to have the same strength, color, fracture, and malleability, it will also be found that all alloys between these compositions will possess the same properties, and hence that, instead of the particular alloys mentioned only being suitable for forging, all the alloys between the extreme compositions mentioned also possess that quality. In the figures given from Mallet under the heads of " order of ductility," " order of malleability," " hardness," and " order of fusibility," the maximum of each of these properties is re- presented by i. The figures given by Mallet for tenacity are confirmed by experiments of the Author, with a few very marked excep- tions. These exceptions are, chiefly, the figures for copper, for zinc, and for CuZn 2 (32.85 copper, 67.15 zinc). The figures for CuZn 2 , as given by Mallet, can, in the opinion of the Author^ only be explained on the supposition that the alloy tested was not CuZn 2 (32.85 copper, 67.15 zinc), but another, containing a percentage of copper probably as high as 55. The figure for the specific gravity (8.283) given by Mallet, indicates this to be the case, as does the color. The figure for ductility would indicate even a higher percentage of copper. The name " watchmaker's brass " in the column of remarks must be an error, as that alloy is a brittle silver-white, and ex- tremely weak metal. The figures of Calvert and Johnson and Riche, as well as BRASSES AND OTHER COPPER-ZINC ALLOYS. I /I those of the Author, give a more regular curve than can be constructed from the figures of Mallet. The specific gravities in Riche's experiments were obtained both from the ingot and from powder. In some cases one, and in some cases the other, gave highest results. In the table, under the head of " specific gravity," Riche's high- est average figures are given, whether these are from the ingot or from fine powder, as probably the most nearly cor- rect. The figures by the other method, in each case, are given in the column of remarks. The figures of Riche and Calvert and Johnson are scarcely sufficient in number to show definitely the law relating specific gravity to composition, and the curves from their figures vary considerably. The figures of the Author being much more numerous than those of earlier experimenters, a much more regular curve is obtained, es- pecially in that portion of the series which includes the yel- low, or useful metals. The irregularity in that part of the curve which includes the bluish-gray metals is, no doubt, due to blow-holes, as the specific gravities were in all cases deter- mined from pieces of considerable size. If it were determined from powder, it is probable that a more regular set of obser- vations could be obtained, and that these would show a higher figure than 7.143, that obtained for cast zinc. Matthiessen's figure for pure zinc, 7.148, agrees very closely with that ob- tained by the Author for the cast zinc, which contained about I per cent, of lead. The figures for hardness given by Calvert and Johnson were obtained by means of an indenting tool. The figures are on a scale in which the figure for cast iron is taken as 1,000. The alloys opposite which the word " broke " appears, were much harder than cast iron, and the indenting tool broke them instead of making an indentation. The figures of al- loys containing 17.05, 20.44, 2 5-5 2 an< ^ 33-94 P er cent - zinc, have nearly the same figures for hardness, varying only from 427.08 to 472.92. This corresponds with what has been stated by the Author in regard to the similarity in strength, color, and other properties of alloys between these compositions. CHAPTER VI. THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 93. Other Alloys than Bronzes and Brasses exist in im mense variety and have numerous applications in the Arts, although of far less common application than the classes of alloys already described. Of these alloys, the most important are those which most closely resemble the true bronzes and brasses in composition, as alloys consisting of bronze or brass with which are united smaller proportions of lead, iron, nickel, antimony, bismuth, and other common metais. In this class also fall the "Kal- choids" as the Author would call them, or the copper-tin-zinc alloys which are usually called brass or bronze accordingly as zinc or tin predominates. The white " anti-friction " or "anti-attrition" metals, the fusible alloys, and type and stereotype metals, all come within this classification. 94. The Kalchoids (Gr. Kalchos\ or Copper-Tin-Zinc Alloys, are of great value and include the strongest, and probably the hardest, possible combinations of these metals. They are, in most respects, usually, intermediate between the brasses and the bronzes obtained by uniting two metals. According to MargrafT, these alloys are often very valu- able and have the character as per table on next page. Mackensie finds the alloy, copper 58, zinc 25, tin 17, excellent for castings and a good statuary bronze; and pro- poses copper 50, zinc 22, tin 28, for mirrors for telescopes ; it is slightly yellow and takes a very fine polish. Bronzes in which equal parts tin and zinc are used are of common use for very small articles as u brass " buttons. Knives for cotton printers' rolls are often made of copper 82, zinc 10, tin 8. Depretz' " chrisocalle " is of copper 92, tin 6, zinc 6, KALCHOIDS AND MISCELLANEOUS ALLOYS. 173 it has a beautiful golden color. Another composition imitat- ing gold is, copper 81.5, zinc 8, tin 0.5 ; and still another, which retains its lustre well, is of copper 80, zinc 17, tin 3; it is used for the small parts of ornamented pistols, etc. Alloys containing these metals are used for bronze medals, the zinc and tin being introduced to the extent of from 2 to 8 per cent, and the total of both being usually 10 per cent, or less. The percentage of zinc is usually kept under 3 or 4 in ordnance metal. TABLE XXIII. COPPER-TIN-ZINC ALLOYS. NO. COPPER. TIN. ZINC. REMARKS. I IOO IOO IOO Very white, brittle, subject to liquation. 2 100 50 50 but finer grain. 3 IOO 25 50 Yellowish tint, hard, fine, not malleable. 4 IOO 25 25 Brittle. 5 IOO 20 20 Brittle, hard, yellow. 6 IOO 16 16 " close grained. 7 IOO 14 14 Yellow, slightly malleable. 8 IOO 12.5 12.5 " more malleable. 9 IOO ii II 10 IOO 10 10 Fine yellow, fine grain, malleable. ii IOO 8 8 Yellow, softer, more malleable. 12 IOO 7 7 Golden, malleable, soft. 13 IOO 6 6 << The use of 8 to 15 per cent, of tin and 2 per cent, zinc in alloy with copper is probably as common as the employment of the bronzes without zinc ; the latter is added to improve the color. Alloys of copper containing from 3 to 8 or 10 per cent, zinc and from 8 to 15 per cent, tin are used in engineer- ing very extensively, the softer alloys for pump-work, the harder for turned work and for nuts and bearings. An alloy of 5 per cent, tin, 5 zinc and 90 copper is cast into ingots and remelted for general purposes. It is tough, strong and sound. Copper 75, tin 12, zinc 3 makes a good mixture for heavy journal-bearings. Copper 76, tin 12, zinc 12, is as hard as tempered steel and was made into a razor-blade by its 1/4 MATERIALS OF ENGINEERING NON-FERROUS METALS. discoverer, Sir F. Chantrey.* When copper and brass are mixed in equal proportions and their sum is equal to the weight of tin, the alloy constitutes a solder. 95. Copper, Zinc and Iron unite with some difficulty, and the presence of iron is thought to make brass harder, to weaken it, and to increase its liability to tarnish. A ternary alloy of this character was introduced in England as early as 1822 and was claimed to be stronger and better for the pres- ence of the iron. An alloy of I per cent, brass with 99 of iron was advised for castings exposed to corrosion, and Kars- ten found that it was harder than the cast iron, and considered it well adapted for use in steam engine cylinders and heavily loaded journal bearings. Herve found the zinc less desira- ble in copper-iron alloys than tin. He states that alloys containing 1.33 to 4 per cent, copper and 0.65 to 3 per cent, zinc were stronger than the cast iron with which they were alloyed. Sterro-metal, elsewhere described, is a metal of this kind, containing also a small amount of tin. 96. Copper, Tin and Iron may be alloyed to make a ferrous bronze of great value. The introduction of cast-iron into gun-bronze (copper 89, tin n, or copper 90, tin 10) is not only useful, in small amounts as a flux, but this ferrous alloy is harder and stronger than the bronze alone. This alloy was made in Russian arsenals about 18205, and used for ordnance. The maximum proportion of iron was from 12 to 25 per cent., according to the use intended. The guns made of these alloys were found, according to Depretz, to excel good gun-bronze ordnance in strength and endurance. Similar alloys were made in France by the Messrs. Darcet f and by M. Dussaussoy, of the artillery, and on a large scale, in the government foundry at Douai. The latter experiments were made with alloys containing : Copper. Tin. Iron. Copper. Tin. Iron. 90 10 6 9 10 4 90 10 3 * Holtzapffel. \ Alliages Metalliques, p. 333. KALCHOIDS AND MISCELLANEOUS ALLOYS. 175 The results were not such as to lead to the adoption of these alloys in making field guns. Wrought iron was introduced into standard gun-bronze by Dussaussoy as early as 1817, using tin-plate for the pur- pose. When the proportion of iron exceeded 2 per cent, the result was not satisfactory. For small articles, the ferrous bronze was found an improvement, it being stronger, harder and less fusible. Gen. Goguel, of the Russian Army, added 12 per cent, of wrought iron to gun-bronze, and reported that the ordnance made of this alloy proved much superior to that made of common gun-bronze. Subsequently, an extended investigation was made by the order of the French govern- ment by MM. Gay Lussac and Darcet, and later by M. Herve of the French Artillery. The former research led to no result ; the last named investigator concluded that the use of tin in securing an alloy of iron with copper is of ad- vantage and that re-fusion is advisable to secure the best results. 97. Manganese Bronze is said to have qualities resem- bling those of phosphor-bronze, the introduction of man- ganese increasing the strength, ductility and homogeneous- ness of the alloy. The manganese alloys are usually white tinged with red, ductile, hard and tenacious. They are often known as white brass, white bronze or white alloys ; they take a fine polish ; those richest in copper have a decided rose hue. These alloys, as well as the phosphor- bronzes, are in somewhat extensive use, especially in Great Britain. Copper and manganese alloy easily, or with difficulty, under different conditions, making a metal of considerable mallea- bility, red in color, turning green when weather stained. It is less fusible than copper, lighter in color, and more liable to tarnish ; it may be made by fusing together copper and the black oxide of manganese. Manganese bronze contains iron, also, and is made by melting together copper and spie- geleisen or " ferro-manganese." When containing 10 per cent, manganese, the alloy of copper and this metal is dense, grayish-white with a tinge of red, very ductile and malleable. 176 MATERIALS OF ENGINEERING NON-FERROUS METALS. and of rather a short fracture ; with 20 per cent, manganese, the color is silver-white to tin white, strong and ductile, with a fine lustre ; with 30 per cent, manganese, the properties remain little altered ; with 40 per cent., the alloy becomes iron-gray, malleable and ductile, very strong, fracture inclined to fibrous. Thus, according to Berthier, all these alloys are ductile, strong, compact and homogeneous. Manganese-bronze is very similar in its general character- istics to phosphor-bronze ; but is a white alloy and differs in being a triple compound of the metals, copper, tin and man- ganese, instead of an alloy of copper and tin fluxed with a metalloid. It possesses some peculiarities which give very great value to this metal as a material of construction. It is remarkably hard, tough and elastic, has rather a high elastic limit, as compared with ordinary bronze, and is found to be very durable when used for bearings of machinery. A common pro- portion of its constituents is, copper, 88, tin, 10, manganese, 2. 98. Preparation and Uses of Manganese-Bronze. As described by the inventor, Mr. P. M. Parsons, white bronze, or manganese-bronze, is prepared by combining ferro-man- ganese, in different proportions, with various bronze alloys, thus producing qualities suited to various uses. The ferro- manganese is first subjected to a refining process, by which the silicon is eliminated, and the proportion between the iron and manganese adjusted in various degrees, for use according to the quality of bronze to-be produced. To effect this com- bination, the temperature of the copper must be brought up to the melting point of the ferro-manganese, which is melted separately and then added in a fluid state. The effect of this combination is similar to that produced by the addition of ferro-manganese to decarbonized iron in the Bessemer converter. The manganese in its metallic state having a strong affinity for oxygen, cleanses the copper of oxides, and renders the metal more dense and homogeneous. A portion of the manganese is utilized in this manner, while the remainder, with the iron, becomes permanently combined with the copper, and plays an important part in improving and modifying the quality of the bronzes prepared from the KALCHOIDS AND MISCELLANEOUS ALLOYS. 1 77 copper thus treated, the effect being to increase their strength, hardness, toughness in various degrees, according to the quality and quantity of the ferro-manganese employed. Manganese, when once incorporated with the copper, is not driven off by remelting ; the quality of the manganese-bronze is improved by remelting. Manganese-bronze, as is stated, when forged, is remarkable for its strength and toughness, having an average tensile strength equal to mild steel, and elongating as much before breaking. It is suitable for forgings of all kinds, for bolts and nuts for engine and machine work, for ships' bolts, rud- der and other fittings, screws, pins, nails, pump-rods, wire, and for all purposes for which yellow metal, brass, and cop- per are employed. In forging this metal, it should be heated to a clear cherry red (not bright), when it may be hammered, rolled, pressed, or worked in any way as long as it retains any color. It should not be worked at a black heat, but when the color is just fading it should be reheated. In rolled sheets and plates it can be worked both hot and cold. In working hot, the instructions given for forgings should be followed. The metal can be rolled, stamped, pressed, and worked cold like brass or copper, being annealed as required. It is stronger, stiffer, and harder than copper, brass, or yellow metal, for which it can be substituted for purposes to which these are applied. The rods, plates, sheets and angles are supplied of mild, medium, or high qualities, as required. The mild and medium qualities have a tensile strength of 28 tons per square inch (4,410 kgs. per sq. cm.), with an elastic limit at 40 per cent, and stretch from 28 to 45 per cent, before breaking. These qualities can be worked and riveted up cold, and are claimed to be greatly superior to yellow metal or gun metal. When ships' screws are made of this material, they are given less thickness than when made of mild steel or of com- mon bronze; it is not subject to alteration of form when taken from the mould or by the annealing which must be done with steel castings ; it retains a clean surface remarkably well, but its cost is considerable. 12 1/8 MATERIALS OF ENGINEERING NON-FERROUS METALS. The ferro-manganese used to mix with gun metal con- tains from 10 to 40 per cent, of metallic manganese ; with brass alloys, 5 to 20 per cent., and with bronze alloys, the proportion lies between the above, according to the propor- tions of tin and zinc employed. To prepare ferro-manganese containing a given amount of metallic manganese, the invent- or melts rich ferro-manganese, containing up to 70 per cent., in a crucible under powdered charcoal, and with a quantity of the purest wrought-iron scrap. If it is desired to employ a ferro-manganese to mix with any of the alloys containing 20 per cent, of manganese, a ferro-manganese containing 60 per cent, of metallic manganese, and, say, I per cent, of silicon, is melted with wrought-iron scrap, in the proportion of 100 of ferro-manganese to 300 scrap. Then a ferro-manganese containing 20 per cent, of metallic manganese will be ob- tained, in which there is only one-third of I per cent, of silicon. Dry sand or loam moulds are recommended for casting. Metal moulds render the alloy somewhat harder and closer in texture. Manganese-bronze is said to be much less subject to cor- rosion. in salt water than is pure copper. Alloys containing from 75 to 85 per cent, copper are most usually adopted for machinery. Zinc often forms a constituent of these alloys, in the proportion of from 2 to 10 per cent. The addition of manganese to bronzes and brasses gives them much lighter color, greater hardness and tenacity, with- out proportionally decreasing ductility and resilience. Cop- per and manganese alone form white alloys of great hardness, strength and ductility. Some of these alloys forge well and can be rolled with ease. They are somewhat susceptible to the action of the atmosphere at high temperature, and should be worked as little and at as low temperature as pos- sible. 99. Aluminium- Bronze. Aluminium is added to copper and to the bronzes and brasses with good results. The alloy, copper 90, aluminium 10, may be worked cold or hot like wrought iron, but not welded. Its tenacity is sometimes KALCHOIDS AND MISCELLANEOUS ALLOYS. 179 nearly 100,000 pounds per square inch (7,030 kilos per square mm.), and its average is not far from three-fourths as great. It is hard and stiff and very homogeneous. Wire has been given a tenacity exceeding 125,000 pounds per square inch (8,776 kilos per square mm.). Its specific gravity is 7.7. In compression this alloy has been found capable of sustaining a little more than in tension (130,000 pounds per square inch, 9,139 kilos per square mm.), and its ductility and toughness were such that it did not even crack when distorted by this load. It is so ductile and malleable that it can be drawn down under the hammer to the fineness of a cambric needle. Measuring its stiffness, the Messrs. Simms found * that it had three times that of gun -bronze and 44 times that of brass. It works well, casts well, holds a fine surface under the tool, and when exposed to the weather ; and it is, in every respect, considered the best bronze yet known. Its high cost alone prevents its extensive use in the arts. Alloying 2 to 8 per cent, copper with aluminium raises its tenacity 65 to 90 per cent., making it, weight for weight, stronger than machinery steel, f Pure, it has a tenacity of about 30,000 Ibs. per square inch, and a modulus about 11,000,000. The density of aluminium-bronze has been determined by M. Riche,J with the following results: BRONZE CONTAINING TEN PER CENT. OF ALUMINIUM. DENSITY. I. WT. = 120^.568. II. WT. = 120^ .275. After casting 7.705 7.706 7.706 7-707 7-703 7.703 7.701 7.699 7.704 7.704 7.705 7.707 7.704 7.702 7-702 7.703 After tempering After tempering . After annealing After tempering . . After impact * Ure's Diet.. Art. Aluminium. f Rail-way Review, Jan. 7, 1891. Ann de Chimie, vol. xxx., 1873, pp. 351-419. Appendix. 180 MATERIALS OF ENGINEERING NON-FERROUS METALS. BRONZE CONTAINING FIVE PER CENT. OF ALUMINIUM. . DENSITY. I. \VT. = 129". 575. II. WT. I29* r .l6l. After casting^ 8.252 8.259 8.255 8.257 8.257 8.264 8.263 8.263 8.262 8.259 8.262 8.262 8.262 8.264 8.264 8.265 After tempering . .. After tempering After annealing After tempering . . After impact Tempering, annealing, and mechanical action produce no noticeable variation in the volume. These alloys are very uniform in character and work regu- larly and smoothly. 100. Uses of Aluminium-Bronze. Aluminium-bronze, composed of 9 parts copper and I part aluminium, was pro- posed in 1864 as a material for small coins, and with this ob- ject in view the assayer of the United States mint made a number of careful experiments with it. The assayer states that aluminium-bronze possesses much greater hardness than copper alone, but less malleability and ductility. When rolled into sheets, it requires annealing at every third pas- sage through the rolls ; when drawn into wire it must also be frequently annealed. To strike a coin of this bronze required unusual force. It tarnishes quite readily, but not more so than copper. Aluminium-bronze containing ^/^ per cent, of aluminium is greenish in color, according to Morin, while other compo- sitions on either side are golden. Even I per cent, added to copper causes a considerable increase in ductility and fusi- bility, and enables it to be used satisfactorily in making castings. Two per cent, gives a mixture used for castings which are to be worked with a chisel. The standard alumin- ium-bronze 10 per cent, aluminium is brittle after the first fusion, but becomes more ductile as well as stronger by repeated refusion. It makes good castings, is easily worked, KALCHOIDS AND MISCELLANEO US ALLO VS. 1 8 1 and may be forged at a red heat, and is fairly ductile under the hammer even when cold. It is softened by sudden cool- ing from a red heat. It takes a fine polish, is a half stronger than good wrought iron in tension, but has less strength in compression. Its coefficient of expansion is small at ordinary temperatures. Its liability to crack in large masses makes it difficult to get large castings. It has great elasticity when made into springs ; it is found useful for watches, and has the decided advantage over steel of being but little liable to oxi- dation ; the addition of 5 per cent, silver is advised to pure aluminium to make springs. Kettles of this alloy have been used in making fruit syrup and preserves. The alloy of aluminium with 4 to 5 per cent, silver is used in making balances for chemists. The introduction of a very minute proportion of bismuth makes this metal very brittle. Steel containing but 0.08 per cent, aluminium is said to be greatly improved by its presence. An alloy of 2 or 3 copper and 97 or 98 aluminium is found useful in making ornamental silver-colored castings which are to be chased and engraved. The alloys of aluminium and copper may be made by fus- ing together the oxides with metallic copper and enough car- bon and flux to reduce them. The oxides, as well as the other materials, should be as finely divided as possible, and the carbon introduced in excess. 101. Copper and Nickel are quite easily alloyed, giving a metal of usually white color, hard, rather brittle, and quite easily oxidized. When the nickel forms 30 per cent, of the whole, the alloy is easily fused, strong, and tough, of a silvery- gray color, and slightly magnetic. White copper and Ger- man silver consist wholly or partly of this alloy. Copper and nickel unite in a wide .range of proportions. In color they range from the red of copper to the blue-white of nickel, according to their proportions. Adding nickel in the proportion of o.io, the alloy is very ductile, light copper- red in color, and moderately strong; with 0.15 nickel, the color becomes very light red and the ductility is still great ; 0.25 nickel gives an alloy nearly white; 0.30 nickel produces 182 MATERIALS OF ENGINEERING NON-FERROUS METAL*. a silver-white metal. Berthier's alloy, copper 0.682, nickel 0.318, is fusible, ductile, strong, bluish-white, slightly mag- netic and somewhat crystalline near the surface. " White copper," so-called, is such an alloy, usually con- taining slight quantities of iron and silicon. Nickel coinage is now used by several nations ; it was first privately coined by Feuchtwanger, of New York City, in 1837; Switzerland began using it in 1850, the United States in 1857, and Belgium in 1860. The U. S. coins now contain copper 75, nickel 25. 102. German Silver. Copper, zinc, and nickel alloy readily. These compositions were used at a very early date in China, and have been known as packfong, tutenag, and white copper. The East Indian or Chinese tutenag is a grayish-white alloy, somewhat sonorous, and brittle. Its composition has been given as copper 44, zinc 40, nickel 16. The other alloys above named are nearly silver-white, malle- able hot or cold, have a beautiful lustre, and very sonorous. The specific gravity is 8.5. Alloys of European manufacture, of similar characteristics, are now common. Viennese alloys have been found by Gersdorff to contain : Table utensils ; copper,- 50 ; zinc, 25 ; nickel, 25. Ornaments " 55 ; " 25 ; " 20. Sheet metal " 60; " 20; " 20. Prick's alloys contain copper, 50 to 55; zinc, 30 to 31; nickel, 17 to 19. These are white and hard but ductile, and have a specific gravity from 8.5 to 8.6 ; they are used in making table utensils and ornamental objects. The alloy, copper 56, zinc 5, and nickel 39, makes a fine white metal of the same class with the preceding. German sliver, as made by good makers, consists usually of Copper 60 Zinc 20 Nickel '. 20 100 KALCHOIDS AND MISCELLANEOUS ALLOYS. 183 Guillemin introduces sodium, thus: Copper 58.00 Zinc 16.65 Nickel 25.00 Sodium o. 35 Sound castings are secured by the use of borax, glass, or other good flux. German silver is rolled cold, and the rolls are necessarily made of very great strength ; frequent anneal- ing is necessary during the process. 103. Copper and Iron unite, when the latter is in small amount, to produce a stronger metal than can be obtained without the iron, even when the copper is alloyed with other strengthening elements ; and iron forms a part of nearly all manganese bronzes, of the bronze known as Austrian " sterro- metal," and of various other useful compositions. The ductility is rather improved than otherwise. Copper and iron unite at high temperatures, if the heat is sufficiently prolonged, and in any proportions. The addition of copper to iron causes brittleness, or " red-shortness." The Author has found that minute doses of copper confer in- creased strength on some steels, and Tredgold states that the same effect is observed on cast iron. Berthier and Rinmann think that one per cent, copper will have a good effect on cast iron. The color of the alloy changes, losing the gray and becoming red, as the proportion of copper increases, up to equal parts copper and iron, when the alloy loses all tint of gray. An alloy of copper 66.67, iron 33.33, is the strongest of these alloys. Mushet has made a number of these alloys. He finds that the presence of carbon causes difficulty in making them. Karsten found that the copper-iron alloys do not as readily dissolve in sulphuric acid as does iron. A ductile alloy was made by Rinmann of copper 16, iron I ; it is magnetic, harder than copper, and the fractured sur- face has a beautiful red color. Eight parts copper and from 1 84 MATERIALS OF ENGINEERING-NON-FERROUS METALS. I to 4 parts iron produce alloys harder than the preceding, but not appreciably less ductile or less red than copper. Copper and cast iron alloy to form a strong metal, also. Riche has successfully produced alloys of copper and iron ; but they are somewhat variable in composition and quality ; thus : He heated in a temperature sufficient to melt cast iron Copper 90 Cast iron 10 The ingot obtained contained, at the top, iron uncom- bined. He heated very hot and held some time in fusion Copper 90 Rivets 10 The ingot obtained furnished upon analysis Top 1, 600 iron.. Bottom 365 iron. He heated very hot and kept melted some time Copper 96 Rivets 6 The metal appeared very homogeneous. Its density, taken at two different points, gave 8.881 8.876 The metal is easily forged, stretches and coils upon itself without breaking. It is rolled with such facility that, without annealing, a bar of it can be reduced from a thickness of 9 millimetres (0.35 inch) to that of I millimetre (0.04 inch). Its tenacity exceeds that of copper. Examining with a magnifying glass the plates I millimetre in thickness mentioned above, gray spots may be seen at certain points, but analysis of these points shows no material KALCHOIDS AND MISCELLANEOUS ALLOYS. I8 S difference between them and other portions. There was found Iron 5.383 5.285 5.236 This substance made very hot in the crucible gives a but- ton in which there remains only Iron 0.167 percent. These two metals were alloyed in variable proportions, melted in earthen tubes 15 centimetres (5.9 inches) in length, and after being kept three hours in fusion, were left to cool slowly. Analysis then gave : IRON, PER CENT. Top of bar. Bottom of bar. Density. I 12 6q^ 4- ( ?4 t ? 8.839 t 8.771 2 92QO * 680 6 8?6 J.UOU 1.O52 4 . 4.6lQ 4. 52O 4.226 4.288 8.885 6 .... 2 Q^O 2 6OO The addition to copper of small quantities of foreign matter, iron, for example, increases the porosity, as do small quantities of oxygen. The copper acquires tenacity and elasticity by this addition of iron, while retaining some malle- ability. 104. Copper-Antimony Alloys. Antimony p , added to the copper-tin alloys, rich in the latter metal, is largely used for a lining metal in journal-bearings. Babbitt's Metal is the best known of these metals, and contains 4 parts copper, 96 of tin, 8 of regulus of antimony. It is made** by melting 4 parts of copper, adding 12 parts best tin, 8 of regulus of antimony, then 12 of tin while cooling the molten mixture. Of this " hardening metal," one part is added to twice as much tin to make the lining metal. Copper I, tin 9, without antimony, is also known as Babbitt Metal ; it is a usual composition in * Haswell. 1 86 MATERIALS OF ENGINEERING NON-FERROUS METALS, government work. This composition has been found ex- cellent in locomotive practice and more satisfactory than that containing antimony. Copper and antimony alloy in the proportion, copper 85, antimony 15, to form, according to Karsten, a brittle metal of little value. Equal parts copper and antimony unite to make a brittle, light-violet colored alloy, of which no use is made in the arts. 105. Copper and Bismuth unite readily and at a temper- ature below that of fusion of copper. The addition of bis- muth causes brittleness, and all ductility is lost when the proportion approaches I per cent. Minute quantities may be added to copper, and if not above 0.5 per cent, the alloy may be hammered and rolled ; exceeding that proportion, the alloy becomes brittle with working and too much so to be safely used. The color of the alloy is light red ; its density is the mean of its constituents. Prince's Metal is said to be an alloy of copper and bismuth, 106. Bismuth-Bronze. Webster's bismuth-bronze is made of various proportions. According to the statement of the discoverer, its composition and qualities are as follows : For a hard alloy, take I part of bismuth and 16 parts of tin, both by weight, and, having melted them, mix them thoroughly. For a hard bismuth bronze, take 69 parts of copper, 21 parts spelter, 9 parts nickel and I part of the alloy of bismuth and tin. This bismuth-bronze is a hard, tough and sonorous metallic alloy, which is proposed for use in the manufacture of screw-propeller blades, shafts, tubes and other appliances employed partially or constantly in sea water. In consequence of its toughness it is thought to be well suited for telegraph wires and other similar pur- poses where much stress is borne by the wires. From its sonorous quality it is well adapted for piano and other wires. For domestic utensils and articles exposed to at- mospheric influences, use I part bismuth, one part aluminium and 15 parts tin melted together to form the separate or preliminary alloy, which is added in the proportion of I per cent, to the above described alloy of copper, spelter and nickel. KALCHOIDS AND MISCELLANEOUS ALLOYS. 1 87 This bronze forms a bright and hard alloy suited for the manufacture of utensils or articles exposed to oxidation. 107. Copper and Cadmium form an alloy similar in char- acter to those of bismuth and copper. 108. Copper and Lead unite with difficulty, and a good alloy can only be obtained with a small quantity of lead. One-tenth per cent, lead gives a mixture observably less duc- tile than copper, and when three times this quantity is intro- duced the alloy has the singular property of working better cold than hot. The combining temperature is so high that the lead usually gives off fumes of oxide ; the cooling should be done rapidly. The alloy has a lower density than the mean of its constituents and is rarely stable. An alloy of copper 20, lead 80, is sometimes used in type- foundries for large type. This, like all those alloys, if kept in a state approaching that of fusion, is subject to separation or "liquation," the lead separating and leaving the copper in a porous mass. When the alloy oxidizes, the oxide is found to contain much more than the proportion of lead contained in the alloy. Common " pot-metal " contains 20 per cent, lead. It is brittle when heated ; larger amounts of lead render the alloy difficult to work and injure it seriously. The fusibility is greatly increased by the presence of the lead. Copper and lead are not easily alloyed, but form, when combined, a metal of gray color, brittle, and of feeble affinity. An alloy of lead 4, copper I, is sometimes used for large type. The constituents are very liable to separation, when kept molten, by liquation. Norway copper, from Drontheim, con- tains a half per cent, lead ; it is preferred in making brass. Other coppers often contain \ l / 2 or 2 per cent. lead. 109. Copper and Silicon, with or without tin, may be alloyed to form "silicon-bronze." Weiller's alloy is made by the introduction of sodium to reduce silica in the cru- cible. This bronze has been used to take the place of phosphor-bronze for telegraph wires in Southern Europe. The inventor recommends the following proportions : fluo- silicate of potash, 450 grams ; glass in powder, 600 grams ; chloride of sodium, 250 grams ; carbonate of soda, 75 grams; 1 88 MATERIALS OF ENGINEERING NON-FERROUS METALS. carbonate of lime, 60 grams ; and dried chloride of calcium, 500 grams. The mixture of these substances is heated, in a plumbago retort, to a temperature a little below the point when they begin to react on one another, and it is then placed in a copper or bronze bath, when the combination of the silicium takes place, as already said. 1 10. Use of Silicon-Bronze. The superiority of silicon is claimed to be due to its better adaptability to being worked at a high temperature, by its penetrating the metal better, and, consequently, insuring the indispensable homo- geneity. It is said of silicon-bronze, that it possesses the conducting qualities of the best copper, with the resisting qualities of the best iron, and that each of these advantages may be varied at will, at the expense of the other. Applied to aerial telegraph lines, the present galvanized wires of the great lines, 5 millimetres (0.2 inch) in diameter, and weighing 155 kilos per kilometre (120 pounds per mile), can be replaced by silicon-bronze wires of 2 millimetres (0.08 inch) in diameter, weighing only 26 kilos to the kilometre (20 pounds per mile) ; while the ordinary steel telephone wires of 2 millimetres (0.08 inch) diameter, and 25 kilos to the kilometre (20 pounds per mile), may be replaced by sili- con wires of only i^V millimetre (0.04 inch) in diameter, and weighing 8 kilos to the kilometre (6 pounds per mile). in. Copper, Tin, and Lead alloy readily, and are thus used in the manufacture of art-castings, for which purpose this composition was also used by the ancients. Statues made by the Romans have been found to contain lead in a propor- tion equal to about one-fourth that of the tin. Klaproth finds in an antique mirror, copper 62, tin 32, lead 6. The pres- ence of lead in bronze is usually considered objectionable. Bronzes containing 2 to 15 per cent, lead make the best of bearings. 112. Copper, Tin, Antimony, and Bismuth united, form a " pewter," once in common use for tableware ; it is a beau- tiful alloy resembling silver, but too readily tarnished, and too soft to be very valuable. It contains copper 3^, tin 88^, antimony 7, bismuth I. KALCHOIDS AND MISCELLANEOUS ALLOYS. 189 113. Copper, Tin, Zinc, and Iron are found in bell metal, and make, in certain proportions, an excellent alloy. The alloy is not made for the market. The above metals, alloyed with nickel, iorm"melchior" a composition containing: of copper, 55 ; nickel, 23; zinc, 17; iron, 3; tin, 2. ^ Argenthal is a similar metal. They are white alloys and used for ornamental castings. Their lustre is silvery and quite per- manent. 114. Copper and Mercury alloy freely. A composition of 25 parts copper in fine powder, obtained by precipitation from solutions of the oxide by hydrogen, or of the sulphate by zinc, washed with sulphuric acid and amalgamated with 7 parts of mercury, after being well washed and dried, is moderately hard, takes a good polish, and makes a fine solder for low temperatures. It will adhere to glass. Droniers malleable bronze is made by adding one per cent, of mercury to the tin when hot, and this amalgam is carefully introduced into the molten copper. 115. Complex Copper Alloys. An alloy imitating gold is made thus : Melt together pure copper, platinum, and tungstic acid, in proportion as follows : Copper 800, 25 of platinum, 10 of tungstic acid, 175 of gold. When com- pletely melted, stir and granulate by running into water con- taining 500 parts of slacked lime, and the same of carbonate of potash for every cubic metre of water. The granulated metal is next collected, dried, and, after remelting in a cru- cible a small quantity of fine gold is added. An alloy results which, when run into ingots, presents the appearance of red gold of the standard of 75o-ioooths, bears a strong acid test, and has nearly the density of gold. A so-called unoxidizable alloy has the following compo- sition : Iron, 10 parts; nickel, 35 parts; brass, 25 parts; tin, 20 parts; zinc, 10 parts. The castings made of this alloy are cleaned by immersion, while white hot, in a mixture of 60 parts sulphuric acid, 10 parts nitric acid, 5 parts hydrochloric acid, and 25 parts of water. Alloys of copper, tin, zinc, and lead are the most familiar of the complex alloys. 1 90 MATERIALS OF ENGINEERING NON-FERROUS METALS. 116. Bismuth Alloys. The properties of alloys of bis- muth and other useful metals are given in considerable detail by Guettier, as follows : * Alloys of Bismuth and Copper. These alloys are easily made, notwithstanding the difference in the points of fusion of the two metals. They are brittle, and of a pale red color, whatever the proportions employed. For description of the useful alloys with copper, see Articles 105-6, page 1 86. Alloys of Bismuth and Zinc. These alloys are seldom made, and produce a metal more brittle, exhibiting a larger crystallization, with less strength, than zinc or bismuth taken singly. They have little value in the arts. Alloys of Bismuth and Tin. The combinations of bismuth and tin take place easily and in all proportions. A very small quantity of bismuth imparts to tin more hardness, sonorous- ness, lustre, and fusibility. On that account, and for some purposes, a little bismuth is added to tin in order to increase its hardness. But bismuth, being easily oxidized, and often containing arsenic, the alloys of tin and bismuth would be dangerous, if used for the manufacture of culinary vessels. The alloys of bismuth and tin are more fusible than either of the metals taken separately. An alloy of equal parts of the two metals is fusible between a temperature of 100 to 150 Centigrade (2I2-3O2 F.). When tin is alloyed with as little as 5 per cent, of bismuth, its oxide acquires the peculiar yel- lowish-gray color of the bismuth oxide. According to Rud- berg, melted bismuth begins to solidify at 264, and tin at 288 C. (507-55o F.). For the alloys of the two metals the " constant point " is 143 C. (289 F.). Alloys of Bismuth and Lead. These two metals are al- loyed by simple fusion, with ordinary precautions. The alloys are malleable and ductile as long as the proportion of bismuth does not exceed that of lead ; they are more tena- cious than lead. The alloy of bismuth 2 and lead 3 is ten times harder than pure lead. The compounds of bismuth and lead generally have a dark gray color with a tint inter- mediate between the color of tin and that of lead. Their * Guettier : " Guide Pratique des Alliages Metalliques." Paris, 1865. KALCHOIDS AND MISCELLA fracture is lamellar, and their specific gravity greater than the mean specific gravity of either metal taken singly. An alloy of equal parts of bismuth and lead has a specific gravity of 10.71. It is white, lustrous, sensibly harder than lead, and more malleable. The ductility and malleability diminish with an increased proportion of bismuth, while they increase with the excess of lead in the alloy. An alloy of bismuth I and lead 2 is very ductile, and may be rolled into thin sheets with- out cracking. Berthier gives its point of fusion as 166 C. (331 F.). Alloys of Bismuth and Iron. Authorities disagree as to the possibility of combining bismuth and iron. The presence of bismuth in iron tends to render this metal brittle. Alloys of Bismuth and Antimony. These alloys are gray- ish, brittle, lamellar, like the alloys of bismuth and zinc, and have no value in the arts. It will be seen from the preceding that the alloys of bis* muth are not at present of importance in the arts, excepting the fusible alloys made of bismuth and certain white metals, such as tin, lead, etc. The alloys of bismuth with tin, the latter predominating, are the most interesting. The great fusi- bility of the alloys of bismuth and lead will have the effect of making these alloys useful, as also those with tin, as soon as bismuth can be obtained in abundance and at small cost. The action cf the bismuth in alloys is to increase their hardness, fusibility, and brittleness. But, although bismuth renders brittle the metals with whicfi it combines, it does so to a considerably less degree than either arsenic or antimony. Tin and Bismuth alloy to form metals of greater hardness, sonorousness, and fusibility than either tin or bismuth. Equal parts give an alloy which melts at about 300 F. (150 C. nearly), and is called " cuttanego," of which the oxide makes a white enamel. Tin 2, bismuth I, gives an alloy melting at about 325 F. (165 C.), and the alloy tin 8, bismuth I, at 480 F. (200 C.). Tin itself melts at about 440 F. (228 C.), bismuth at 510 F. (265 C). Riche gives the densities of alloys of tin and bismuth as follows : MATERIALS OF ENGINEERING NON-FERROUS METALS. THEORETICAL DENSITY. EXPERIMENTAL DENSITY. DIFFERENCE. REMARKS. Bi 2 Sn 94.26 94^4 + .OO8 Bi Sn Q. i "35 Q. 145 + .OIO Bi Sn 2 V *JJ 8 740 8.754 + .OI4 Bi Sn 3 8 4QI 8.506 + .015 Bi Sn 4 8.qo6 8.^27 + .021 Bi Sn 5 8.174 8. iqq + 025 Maximum contraction. Bi Sn 6 . ... 8 O7T 8 007 4- .024 7QQ4 8 017 + . O2 1 } The maximum contraction should take place in the alloy Bi Sn 5 , which is a silvery-white metal formed of little crystal- line grains commingled. This alloy was not attacked by dis- tilled water ; at the end of several hours it retained its brill- iancy and its silvery lustre. The maximum contraction is seen with the alloy Bi Pb 3 , and on either side of this alloy a very regular diminution in contraction will be noticed. The differences being very great both between the theoretical and experimental density, and between the density of each alloy and that of its neigh- bors, he made but two determinations for each alloy. As analysis of the ends and of the middle of the ingot formed by the alloy BiPb 3 gave the same numbers, it seems, therefore, that this alloy should be considered as a chemical com- pound. Lead and bismuth unite readily, when fused, to form a malleable alloy if the lead is in excess, but a brittle compound if the bismuth is present in large amount. Its color is dark gray, fracture often lamellar, and the density greater than that given by calculation. Equal parts give an alloy having the specific gravity 10.71, white, lustrous, harder and also even more malleable than lead; with lead 3, bismuth I, an alloy of 6 times the tenacity of lead is produced ; lead 2, bis- muth i, gives a very malleable alloy, easily rolled into thin sheets, melting at 325 F. (165 C.), the melting-point of the alloy of equal parts. Riche finds the following densities of alloys of lead and bismuth : THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 193 Density of the lead n . 364 Density of the bismuth 9. 830 THEORETICAL DENSITY. EXPERIMENTAL DENSITY. DIFFERENCE. REMARKS. Bin Pb lO.OQQ IO.232 4-O I*}** Bi Pb IO.28S IO. 5IQ + o 231 Bi Pb 2 10. 536 IO 0^1 + O.3Q5 Bi a Pb 5 10 622 II .038 + o 416 Bi Pb s IO.J.4S 11.108 + O.66O Bi 2 Pb 7 jo 74.8 n 166 4-O 418 Bi Pb 4 IO 7Q7 II. IQ4 + O. *}Q7 Bi Pbs 10 874. II .2OQ + O.3*?5 Bi Pb ro.0^2 11.225 + O.293 Bi Pb 7 IO Q7Q 11.2*35 + O.254 117. Bismuth, Tin, and Lead form a series of "fusible alloys " used in obtaining impressions from objects made of the less fusible metals, and in making " fusible plugs " and other safety apparatus or gauges of temperature. These al- loys are also used as " soft solders.'* Newton's alloy consists of bismuth 50, tin 30, lead 20; it melts at about the boiling-point of water. These alloys are all weak and are of a dull gray color and tarnish readily. Darcet's alloys are the following : TABLE XXIV. DARCET'S FUSIBLE ALLOYS. NO. BISMUTH. LEAD. TIN. REMARKS. I 7 2 4 Softens at the boiling-point of water. 2 8 2 6 Ditto ; easy of oxidation. 3 8 2 4 Ditto ; like butter. 4 16 4 7 Softens still more. 5 9 2 4 " less. 6 7 16 8 5 3 7 4 Becomes nearly liquid at boiling-point, quite " " 8 8 4 4 very 9 16 9 7 Ditto. 10 8 5 3 Melts at 205 F. (95 C.). ii 8 6 2 Ditto. 12 8 7 I Softens. 13 16 15 I Does not melt at 212 F. (100 C.). IQ4 MATERIALS OF ENGINEERING NON-FERROUS METALS. The fusible metals of most common use are : D'Arcet's : Bismuth, 8 ; lead, 5 ; tin, 3 parts. Walker's : Bismuth, 8 ; tin, 4 ; lead, 5 parts ; antimony, I part. The metals should be repeatedly melted and poured into drops, until they can be well mixed previous to fusing them together. Onion's : Lead, 3 ; tin, 2 ; bismuth, 5 parts. Melts at 197 Fahr. (93 C). If, to the latter, after removing it from the fire, one part of warm quicksilver be added, it will remain liquid at 170 Fahr., and become a firm solid only at 140 Fahr. (77 C. ; 60 C.). Another : Bismuth, 2 ; lead, 5 ; tin, 3 parts. Melts in boiling water. They are frequently used to make toy spoons, which sur- prise the uninitiated by melting in hot liquors. A little mer- cury may be added to lower the melting points. The first two are specially adapted for making electrotype moulds. French cliche moulds are made with the second alloy. These alloys are also used to form pencils for writing, also as metal baths in the laboratory, or for soft soldering joints. The committee of the Franklin Institute, experimenting on steam boilers in 1836, made an examination on the be- havior of the " fusible metals," and reported : That the impurities of the commercial metals, lead, tin and bismuth, do not usually affect the melting points of these alloys ; and that the compounds made by alloying them in chemically equivalent proportions do not present the characteristics of chemical compounds. They found that alloys ranging between SnPb and SnPb 6 give nearly the same temperatures of fusion, but differ in their rates of change from the solid, through the plastic to the liquid state. The temperatures of casting and rates of cooling do not affect the melting points. Separation of the metals could be effected by pressure a conclusion confirmed by the later ex- periments of Weems; these alloys, when used in "safety plugs " of steam boilers, should not be exposed to the pres- sure of the steam. Very little change is effected in the THE KALCHOIDS AND MISCELLANEOUS ALLOYS. IQ5 melting point of an alloy of equal parts lead and tin by adding tin ; its melting point was found to be a few degrees lower than reported by Parkes. Parkes and Martin obtain the following : TABLE XXV. FUSION OF ALLOYS OF BISMUTH, TIN AND LEAD. BISMUTH. LEAD. TIN. TEMPERATURE. Parts. Parts. Parts. Fahr. Cen. 8 5 3 202 94-44 8 6 3 208 97.78 8 8 3 226 107 64 8 8 4 2 3 6 112.20 8 8 6 243 II6.05 8 8 8 254 122. IO 8 10 8 266 127.60 8 12 8 270 130.90 8 16 8 300 147.40 8 16 10 304 149.60 8 16 12 294 141 . 90 8 16 14 290 139.70 8 16 16 292 I40.SO 8 16 18 298 I44.IO 8 16 20 304 147.40 8 16 22 312 152.80 8 16 24 316 154-00 8 18 24 312 152.90 8 20 24 310 I5I.9 8 22 24 308 I5I.8O 8 24 24 310 152.90 8 26 24 320 158.40 8 28 24 330 163.00 8 30 24 342 170.50 8 32 24 352 I76.OO 8 32 28 332 165 oo 8 32 30 328 163.90 8 32 32 320 158.40 8 32 34 318 157.30 8 32 36 320 158.40' 8 3 2 38 322 159.50 8 32 40 324 160.60 The thermometer is observed to rise about one degree, Fahr., at the instant of solidifying. These alloys are especially valuable for baths used in tempering steel articles of small size. They give a very exact temperature, which may be adjusted to the purpose 196 MATERIALS OF ENGINEERING NON-FERROUS METALS. intended. They are used by placing the article on the sur- face of the unmelted alloy, and gradually heating until fusion occurs and they fall below the surface, at which moment their temperature is right ; they are then removed and quickly cooled in water. It is not easy, even if possible at all, to give as uniform a temperature by the ordinary processes of heating, or to obtain the exact heat desired, and the quality of the tool is not so easy of adjustment by any other method. The Homberg alloy consists of equal parts of these metals, and melts at about 254 F. (122 C.) ; it is silver white. Krafft's alloy is composed of bismuth 63, lead 25, tin 12; it melts at 220 F. (104 C.). Rose's alloy is a more common one 40 bismuth, 20 lead, 20 tin, or 50 bismuth, 20 lead, 30 tin. Another, Rose's alloy, is of 50 bismuth, 25 each lead and tin, and melts at 205 F. (95 C.). According to Ermann, this alloy fuses at 200 F. (94 C.) and expands from a volume i,at the boiling point of water, to 1.0083 at 114 F. (44 C.), contracts to 0.9913 at 148 F. (70 C.) and then ex- pands to 1.0083 at tne melting point. Dobereiner's alloy, bismuth 46.6, tin 19.4, lead 34, melts at 210 F. (99 C.). Bismuth, Lead and Zinc in equal parts form an alloy which melts in boiling water, according to Mackensie. The melting points of fusible alloys, as determined by Grehm, are as follows (see Art. 120): ALLOYS. SOFTENS MELTS Tin. Lead. atF. atC. at F. atC. 2 2 365 185 372 189 2 6 372 189 383 195 2 7 377* I 9 S 388 198 2 8 3954 202 406 to 410 216 118. Lead and Antimony uniter eadily and in all propor- tions, forming alloys of intermediate character, of which the most familiar is a u type metal," lead 34, antimony I. The THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 197 proportions vary with the size of type and with the character of the work to be done. The alloy is ductile, quite strong, hard enough to bear considerable use without wear or defor- mation, and not so hard as to injure the paper. It fuses at a low cherry-red heat, is not easily oxidized, and differs from lead in most of its qualities simply by possessing greater hardness. Keys of flutes and similar parts of instruments are made of lead 2, antimony I. Shot for guns is often hardened with antimony, and rifle bullets for large game are very frequently similarly made, introducing very small quanties of either tin or antimony or both. Low grade lead sold to shot-makers often contains I or 2 per cent, antimony. The alloy of lead with even a very small percentage of antimony has been found, by Bischoff, to be subject to rapid corrosion by even very pure water. As the salts of lead are poisonous, any use of lead or of its alloys under conditions favorable to the formation of solutions liable to enter into drinking-water or food must be carefully avoided. Riche reports the densities of alloys of lead and antimony as below : Density of the antimony 6.641 Density of the lead 12.364 THEORETICAL DENSITY. EXPERIMENTAL DENSITY. DIFFERENCE. REMARKS. Sb 4 Pb . . 7 2^7 7 214 .023 Sb 3 Pb 7. age 7 ^61 .024 Sb, Pb 7 6*1 7.622 .029 Sb Pb 8.271 8.233 .038 Sb Pbi 9O46 8.QQQ .047 Maximum dilatation. Sb Pb 3 9 CIQ 9. 502 -.008 Sb Pb 4 98lO Q 8l7 .OO2 Sb Pb 5 IO O4O 10.040 Nulle. Sb Pb 6 10 206 IO 211 + .005 Sb Pb 7 IO V\ti IO ^44 4- .ooq Sb Pb 8 IO 4^8 IO-455 + .017 Sb Pb 9 10 521 IO S4I + .020 SbPbio . . . jo <;o2 IO.6I5 -4- .023 Maximum contractioa Sb Pbi , 10.652 10.673 + .021 Sb Pb, 3 10 702 IO.722 + .O2O Sb Pb, 3 IO . 74.6 10.764 + .018 Sb Pb, 4 . . 10 785 IO.SO2 + .OI7 198 MATERIALS OF ENGINEERING NOK-FERROUS METALS. The maximum of contraction corresponds to an atomic alJoy SbPb IO , which has a rather simple composition, and near the alloy SbPb 2 is found the maximum of dilatation. These alloys are crystalline. The alloys near SbPb 2 crys- tallize in quite large scales. Up. Tin and Antimony are easily alloyed, forming a sil- ver or tin-white alloy, according to the proportion of tin, usually brittle, and often sonorous when the antimony is present in considerable amount ; its specific gravity is less than the mean of the two constituents. Berzelius states that the alloy of 3 parts tin to I of antimony can be worked hot, although liable to crack along the edges. Berthier found the alloy, tin 4, antimony I, very malleable and excellent for mak- ing hollow ware and for white-metal cocks ; the mixture, tin 6, antimony i, is also used for such purposes and also for various " pewter " (so-called) articles. This alloy takes a good polish, which slowly disappears with long exposure to the atmosphere. For domestic utensils an alloy of these metals is often used, as free from danger of injuring food cooked or kept in them ; the alloy is not usually affected by the acids to which it is there exposed. Chaudet investigated these alloys with considerable care.* He found that containing equal parts of tin and antimony harder than the latter, brittle and weak, and easily powdered. Its fracture was white and fine grained, and its specific grav- ity 6.8. The alloy of tin 3, antimony i, had a specific gravity of 7.06, was somewhat malleable under the hammer, but very liable to crack ; it had much less ductility than tin. Nitric acid oxidizes these alloys without dissolving them, and the oxide dissolves readily in hydrochloric acid, from which the addition of water causes the precipitation of the metals. 120. Tin and Lead alloy freely in all proportions, and the two metals are often found associated in nature. The addition of lead hardens tin, weakens it, alters its color from * " Alliages Metalliques." THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 199 white to gray, and changes its texture. When 3 parts tin and I of lead are used, the hardest and strongest alloy is produced ; its density is 8. An alloy of tin I, lead 2, is used for a lead-solder and known as plumber's solder, and the proportions are variable up to equal parts of each ; its density is 9.4 to 9.6. Tin 2 or 3, lead I, produce alloys which are very fusible, harder than either lead or tin, and which are used as tinner's solders ; fluxed with resin, they are found valuable in joining all kinds of tin-smith's work; the propor- tion of the constituents is sometimes I to I, and these alloys are known as " soft-solder." According to Watson the densities of these alloys are as follows : TIN. LEAD. S. G. O 10 32 16 8 4 2 I "3 7.2 7-3 7-4 7-6 7-8 8.2 8.8 These alloys have a large number of applications in the arts in making small instruments, apparatus and utensils ; they are used in plating copper, in making organ-pipes, and formerly in domestic utensils for which, however, they are unfitted by the solubility and the poisonous properties of the lead, which are, however, greatly reduced by the presence of the tin. The alloy containing 16 to 18 per cent, lead is not sensibly attacked by vinegar or fruit acids. Alloys used in plating copper contain from 40 to 50 per cent. lead. Of the alloys of these two metals, that containing little or no ob- servable amount of lead is used for domestic utensils ; 8 per cent, lead gives a useful alloy for other dishes ; 20 per cent, lead gives an alloy in considerable demand for ornamental castings. Messrs. Parkes and Martin have determined and tabu- lated the melting points of these alloys, as in the following table : 200 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XXVI. MELTING POINTS OF TIN-LEAD ALLOYS. PROPORTIONS. MELTING POINTS. PROPORTIONS. MELTING POINTS. Tin. Lead. Fahr. Cent. Tin. Lead. Fahr. Cent. 4 4 372 187 4 28 527 271 6 4 336 167 4 30 530 274 8 4 340 169 4 32 532 275 10 4 348 174 4 34 535 277 12 4 336 178 4 3i 538 278 14 4 362 182 4 38 540 279 16 4 367 184 4 40 542 281 18 4 372 188 4 42 . 544 282 20 4 378 190 4 44 546 283 22 4 380 191 4 46 548 284 24 4 382 193 4 48 550 285 4 4 372 187 4 5o 55i 285 4 6 412 209 4 52 552 286 4 8 442 225 4 54 554 287 4 10 470 241 4 56 555 288 4 12 482 248 4 58 556 288 4 14 49 258 4 60 557 289 4 16 498 256 4 62 557 289 4 18 505 260 4 64 557 289 4 20 512 264 4 66 557 289 4 22 517 267 4 68 557 289 4 24 519 268 4 70 558 289 4 26 523 270 Parkes and Martin propose the following alloys for baths used by cutlers and others in tempering and heating steel articles : TABLE XXVII. BATHS FOR TEMPERING. NO. USE. LEAD. TIN. MELTING POINTS. F. c. I 2 3 4 6 8 9 10 II 12 7 74 8 81 10 14 19 30 48 50 Oilb j 4 4 4 4 4 4 4 4 4 4 riling. 4 420 430 442 450 470 490 509 530 550 558 600 612 213 221 226 232 241 252 262 274 28 5 289 312 319 Other surgical instruments. . . . Razors Pen-knives Knives, scalpels etc Chisels, garden knives Hatches Table knives Swords, watch-springs Large springs, small saws Hand saws Articles of low temper THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 2OI Tin and lead in equal parts make an alloy used for organ pipes. It is cast in sheets on a table ; these sheets are beaten smooth with a " planer," trimmed to size, rolled into shape and soldered together at the abutting edges. 121. Tin and Zinc unite, in all proportions, readily and uniformly, the quality varying less with variation of propor- tions than in alloys generally, as may be seen by studying the change of strength exhibited by the map and model shown in the chapter on the ternary alloys. The introduction of zinc increases the hardness of tin, and rather increases its whiteness, when in small proportion ; in larger quantities it reduces ductility perceptibly. The alloy is of granular, some- times crystalline, structure, as revealed by fracture, and is somewhat sonorous. With equal parts tin and zinc the alloy is rather hard, moderately ductile, and of a very brilliant lustre. According to Koechl, the following are melting-points of these alloys : TABLE XXVIII. FUSION OF TIN-ZINC ALLOYS. TIN ZINC TEMPERATURE OF FUSION. Deg. Fahr. Deg. Cent. I 3 500-572 260-300 Pure metals. 2 4 572-662 300-350 " " 3 2 428-680 220-360 i I 472-662 250-350 Commercial. i I 680-932 460-500 Pure metals. The alloy of equal parts of tin and zinc is said by some authorities to be nearly as strong as brass, to be much cheaper, and a better anti-friction metal ; but it is necessary that the zinc should be very pure. This alloy has been used in the form of roofing sheets. The alloy tin 75, zinc 25, makes ex- cellent metal patterns, the alloy flowing freely, running " sharp" and expanding slightly when solidifying ; it should not be overheated, and should be constantly stirred while pouring, 2O2 MA TERIALS OF ENGINEERING NON-FERROUS METALS. to insure uniformity. This metal works easily, turns well in the lathe, and does not clog the file. 122. Antimony, Bismuth, and Lead unite to form an alloy which expands on cooling, and which is therefore used for type-metal. Mackensie's alloy is antimony 16, bismuth 16, lead 68. Stereotype plates of good quality may be made of this composition. 123. Antimony, Tin, and Lead are alloyed in the pro- portion of antimony 17, tin 13, lead 70, to form another Mac- kensie metal for stereotype plates and other printers' work. Sheets of this, or a similar alloy, are used in engraving music for printing ; a composition reported by Berthier is antimony 5, tin 60, lead 35. 124. Antimony, Tin, and Zinc, in the proportions anti- mony 12, tin 44, zinc 44, make an alloy considered excellent for lining pump-barrels. 125. Antimony, Bismuth, Tin, and Lead, in the propor- tions tin 76, bismuth 8, antimony 8, lead 8, form the " Queen's Metal," which is one of the " pewter " alloys of greatest beauty and durability. 126. Pewter and Britannia Metal. Pewter has a wide range of composition, from tin 20, copper I, to tin 2, copper i. The alloy is often mixed with lead, of which the Pewterers* Company in 1772* permitted enough to bring the density of the pewter from fff \ to |||f that of tin. The best Britannia, a metal of this class, is said to be tin 77, antimony 15, copper 7, zinc 2 ; the alloy is cast in flat ingots and rolled into sheets. Britannia wares, made in Sheffield, are often composed of $y 2 parts block tin, 28 parts antimony, 8 of copper, and 8 of brass. The tin is melted and kept at a red heat while the antimony, the copper, and the brass are successively added, molten. The liquid alloy is ladled into the ingot moulds, which are slab-shaped cast-iron boxes, and the slabs thus made are subsequently rolled into sheets or recast into the form desired, or into such shapes as may be easily modified to the necessary extent. Spherical vessels are usually " spun up " in halves, which are then united by soldering. The * British Industries. Bevan, 1871. THE KALCHOIDS AND MISCELLANEOUS ALLOYS. 203 solder is any very fusible composition of this class, and is often made of tin 75, lead 25. The fusibility of the metal is such that it requires some dexterity and great care to prevent its injury in the process of soldering. Britannia is easily shaped by all the familiar processes ; it may be cast, rolled and ham- mered, and cut in the lathe or by hand tools with equal facility. 127. Iron and Manganese have a strong affinity. In small proportions manganese confers whiteness upon iron, and the alloy called " ferro-manganese " is considerably used in making steels containing very little carbon ; the carbide of this alloy, known as " spiegeleisen," or simply " spiegel " in the trade, is used in carburetting iron to produce steels " higher " in carbon. A small proportion of manganese renders iron less fusible, and is said to increase its tenacity. Many of the ingot-irons in the market, called " mild " or " low " steels, contain more manganese than carbon and are very strong and ductile, and make excellent material for use where great changes of tem- perature are not met ; this alloy is not considered suitable for springs, however. In large doses, manganese does not re- duce the ductility and malleability of iron to the extent ob- served with the introduction of carbon. Karsten found that nearly 2 per cent, manganese improved iron. Mushet found that the alloy iron 71, manganese 29, was not magnetic, and concluded that the maximum attainable in iron was 40 per cent, manganese. As the percentage of manganese increases, the alloy becomes whiter, harder, more infusible, and more brittle if the manganese is present in considerable amount ; it is more subject to oxidation also. 128. Platinum and Iridium alloy to form a composition, according to Matthey,* which is homogeneous and is capa- ble of being forged. Its density is 21.5 when of the com- position, platinum 98.5, indium 12.5 by mixture, and platinum 90, iridium 10 by analysis. The density of the iridium was 22.38. The coefficient of expansion was from o to 16 C. (32 to 41 F.), 0.0000254. * Proc. Royal Society, 1878. 204 MATERIALS OF ENGINEERING NON-FERROUS METALS. 129. Spence's " Metal " is not, strictly speaking, a metal, but is a compound obtained by dissolving metallic sulphides in molten sulphur,* which is fo and capable of receiving into solution nearly all known compounds of sulphur and the use- ful metals. It was discovered by J. B. Spence in the year 1879. The solution, on cooling, solidifies, forming a homo- geneous, tenacious mass of the specific gravity 3.37 to 3.7 at o C. (32 F.). According to Dr. Hodgkinson, when finely powdered, it is acted upon slowly by concentrated HC1 and NO a HO in the cold ; in large lumps, little or no action takes place ; the expansion coefficient appears to be small. The fracture is not conchoidal, but somewhat like that of cast iron. It is said to be exceedingly useful in the laboratory for making the air-tight connections between glass tubes by means of caoutchouc, and a water or mercury jacket, where rigidity is no disadvantage ; the fusing point is so low that it may be run into the outer tube on to the caoutchouc, which it grips on cooling, like a vice, and makes it perfectly tight. It melts at 320 F. (160 C.), expands on cooling, is claimed to be capable of resisting well the disintegrating action of the atmosphere, is attacked by but few acids and by them but slowly, or by alkalies, and is insoluble in water, and may re- ceive a high polish ; it makes clear, full castings, taking very perfect impressions ; it is cheap and easily worked. It has been used as a solder for gas-pipes, and as a joint-material in place of lead. * Jour. Society of Arts. London, 1879. CHAPTER VII. MANUFACTURE AND WORKING OF ALLOYS. 130. Alloys of General Application ; Brass Working. Of the alloys described in the preceding chapter but a few are employed by the engineer in his professional work, and still fewer are familiar and in common use. Of all the known alloys, the bronzes and the brasses, the coin alloys and a few compounds of tin, lead, zinc, antimony and bismuth, only, are so well known as to be properly classed among the ma- terials of constructive engineering. All the others are of use only in a restricted range of application and for a few special purposes. The methods of preparation are practically the same for all, and the " brass foundry " is usually resorted to in making them all. Brass work is divided into several branches, which, accord- ing to Aitken, are : 1. Brass casting, or ordinary foundry work; 2. Bell and cabinet-ware casting ; 3. Pot-metal and plumbing work ; 4. Stamped brass-work; 5. Rolled brass ; wire-work; sheathing; 6. Tube making ; 7. Lamp making; 8. Gas fitting ; 9. Naval brass-founding. Several of these lines of work may often be carried on together, but it is usual to combine those most nearly re- lated as those involving casting, those in which the metal is rolled or wire-drawn, stamping, tube-making and brass finishing. 206 MATERIALS OF ENGINEERING NON-FERROUS METALS. Casting is described at length in Arts. 131-2, on the brass foundry. Sheet-rolling is a very important branch of brass-making, employing a large number of work-people and sustaining a host of minor trades. The ingot brass for sheet-brass rolling is cast in broad, shallow, iron ingot-moulds, or when larger masses are to be used, in stone moulds, cut out of the solid block. They are well oiled and powdered with charcoal before filling them. The cast ingots of brass are called " strips," and are rolled, cold, by several successive " passes " through heavy rolls, with occasional annealing as they become hardened by the operation of the rolling-mill. When the surface of the sheet is found to be irregular and to contain spots of im- purity, the hand-scraper, or a scraping machine, is employed to remove them, and thus to prevent liability to cracking and raggedness of surface or edges. When rolled nearly to gauge, the sheet is " pickled," to remove the oxidized surface, and is then passed through the finishing rolls, which are finely polished and give the sheet its final finish. Muntz metals can be rolled hot, and therefore much more cheaply than other brass. Wire-drawing is conducted as in the drawing of iron and steel wire ; but the rods to be drawn are cut, by a slitting- mill, from sheet-brass. Like iron wire, brass must be occa- sionally annealed, in passing from wire-block to wire-block. Stamping in dies can be practised with any of the soft and ductile brasses, or other alloys. It is by this process that a large proportion of the cheap brass ornaments are made, as well as many parts of various utensils, as lamps, door-fixtures and kitchen utensils. The die on the anvil is made of the desired form, and the metal is "struck" into it by the blow of a " drop-hammer" carrying a companion die, the drop falling from one to five feet according to weight and power. Heavy drops are always worked by steam power. The " force," or die carried by the drop, is usually of soft metal ; the die on the anvil is of steel. For fine and small in- tricate work, several blows are struck. This kind of work MANUFACTURE AND WORKING OF ALLOYS. 2O? does not compare favorably with cast brass, or bronze, in clearness and fineness of lines. Brass Tubes are made by either of several methods. Sheet-brass is rolled, over a form, into a tube, and the edges soldered together, or they are rolled into cylindrical shape and soldered. For exact sizing, a mandrel is placed within the tube and on this it is rolled to gauge. Seamless tubes, such as are used in steam boilers and elsewhere under pres- sure, are made by rolling, or by drawing down cast cylinders in a mill consisting of several sets of steel rolls. Brass-finishing includes lacquering, bronzing, dipping and burnishing and other methods of giving a surface finish, described at the end of this chapter. 131. The Brass Foundry is usually an adjunct to large manufacturing establishments. It is generally small, and the moulding room and casting room are in one. A drying room, or core-oven, is conveniently located at the moulding room side ; it may be heated by either steam or by stoves, the for- mer being the better plan. A cleaning room and, beyond it, a finishing or dressing room, should be attached to the foun- dry, and, for fine work, a lacquering room is also required. The " patterns " are of wood or iron, as in iron founding, or they may be of stucco and pipe-clay. Patterns for brass castings must be larger than for iron, as shrinkage is one-half greater, i.e., T \th inch to the foot, or about 20 cm. per metre. The <( shrink-rule" used for iron will not apply for brass-work. The flasks, and all details of apparatus, tools, and work are very similar to those used in an iron foundry, and the meth- ods are the same in the main. Castings are cooled rapidly, often with water, to soften and toughen them. 132. Melting and Casting. In the melting of the ma- terials in the making of alloys in the foundry, two general methods of procedure are practised ; in the one, all the con- stituents are fused at the same time in the same crucible or melting pot ; in the other they are fused one after another in a definite order, which is determined by their relative fusibility, volatility, and liability to oxidation, or to absorb oxygen and other gases. The first of these methods is, perhaps, the most 2O8 MATERIALS OF ENGINEERING NON-FERROUS METALS. common, but the second is by far the better ; thus in making the most common ternary alloys, those of copper, tin, and zinc, the copper is best melted first, the tin should be next introduced, and the zinc, which is volatile and oxidizable, is added last. If lead is to be introduced into such an alloy, it is found best to put it into the crucible last. Other things being equal, the metals should be added in the order of their non-volatility ; the next controlling quality is infusibility ; the least fusible should generally be melted first. The casting and cooling of the alloy is hardly less a mat- ter of importance than the methods of fusion. Liquation is very liable to occur in certain cases, as in many alloys of cop- per with tin, and to prevent it the most prompt cooling pos- sible is resorted to ; the use of " chills," or metal moulds, is sometimes found essential to success. In these cases, it is not advisable to pour the alloy " cold," as liquation may have al- ready commenced ; they should be poured hot " sharp," as the term is often used in the foundry and yet compelled to chill quickly, if possible. The apparatus of the foundry, in which alloys are mixed and cast, consists of an air, or wind, furnace, sufficiently large to receive the crucibles in which the metals are melted, or, sometimes, when the masses handled are very large, a rever- beratory " open hearth " furnace, which is preferably heated with gas or liquid fuel ; of a collection of crucibles, which may be iron melting-pots for lead and alloys which melt at a low heat and have no affinity for iron, but which are usually of clay, of graphite, or of graphite mixed with clay ; and utensils for weighing and handling the metals, fuels, and crucibles. In some cases platinum and silver crucibles are used, as in lab- oratory work, but these are rarely needed. The crucibles should be carefully selected, since the cost of these vessels is often an important item of the expense account. In melting, the constituents of the charge being intro- duced in the order decided to be, on the whole, best, the liquid metal should be carefully stirred after each addition, and in such a manner as to secure most complete intermixture, without liability to injure it by exposure to an oxidizing MANUFACTURE AND WORKING OF ALLOYS. 2OQ atmosphere. When the alloy is not homogeneous and sound, it may sometimes be greatly improved by refusion. In mak- ing large castings, the several metals to be alloyed are usually melted separately and all finally poured together into a reser- voir in which they are thoroughly mixed before " pouring the casting." Where a reverberatory furnace is used, the process may be conducted as in crucibles ; in this case, especial pre- cautions must be observed to preserve a deoxidizing flame within the furnace. W T hen they are used in making bronzes, great care is taken to keep the mass constantly stirred to pre- vent liquation and the floating of the tin to the top. The fuel used in the mint-furnace is generally coke, which should be dense, hard, bright, and should ring when struck. In laige establishments, and especially in melting bronzes, the open-hearth reverberatory is very generally used. Bell founders use a peculiar dome-topped furnace, melting at more moderate heat. In " pouring," the small castings are made first and the heavier are poured with the cooler metal. Sheet-brass is first cast in plates between heavy marble blocks washed with loam and well dried, or, often in ingots. They are rolled in heavy plate-mills and occasionally annealed as they become hard and unmalleable in the rolls. In making brass-plates and sheet-brass, the surface is pickled, after the sheet is reduced nearly to size, in order to give it a clean surface, and then, when a finish is demanded, it is given by a set of polished rolls. Wire-brass is cast and rolled into plates, which are cut into narrow strips in a "slitting-mill " by narrow interlocking roll-collars. These strips are rolled to a conveniently small size, and are then sent to the wire-mill to be finished in the draw-plates. 133. Furnace Manipulation. In filling the furnaces, the crucibles are slowly heated to avoid danger of breaking ; they are at first set bottom upward. When well heated, they are set mouth upward and charged with the broken copper. The tin or zinc is heated at the mouth of the furnace and is added gradually to the copper as the latter becomes fluid. 14 2IO MATERIALS OF ENGINEERING NON-FERROU S METALS. The zinc is liable to volatilization, and is, therefore, when introduced, plunged well below the surface of the molten copper. The Author has sometimes had it wrapped in dry paper or other protecting material to secure protection from loss by volatilization and oxidation. Great care is needed to prevent the introduction of cold and especially of damp metal ; seriously dangerous explosions are sure to take place if this should happen. The fumes arising from the molten alloys when poured are unhealthy, and a form of intermittent fever known as the " brass ague " is often produced by them where proper pre- cautions in handling and in securing ventilation are not observed. The brass-founder's furnace consists of a vertical cast- iron cylinder or other casing often a brick structure lined with fire-brick to a diameter of 10 to 15 inches. The flue is led off at one side at the top, and the whole is covered with a plate having an opening of sufficient size to permit the crucible to enter and fitted with a cover plate. The grate is usually composed of loose bars which can be easily and in- dependently withdrawn or inserted. Each furnace contains one crucible, and large castings are only made where several furnaces are in use or where the alloy can be melted in a reverberatory furnace. Tuyeres are sometimes fitted for the purpose of increasing the rapidity of melting, and the crucibles are then, when large castings are to be made, emptied as fast as ready into a ladle which serves as a collecting reservoir from which the mould is filled. The fuel is usually either coke or charcoal. 134. The Preparation of the Alloys involves considerable knowledge of the behavior of the mixture and its constituents while fusing and while the alloy is being formed, and can only be successful when the skill and judgment of an ex- perienced founder aid in the work of melting and casting. There are two methods of making alloys : the one is that of weighing out the constituents in proper proportions and mixing and melting all together; the other is that of mixing and melting the constituents successively and in an order MANUFACTURE AND WORKING OF ALLOYS. 211 dependent upon the character of the metals and the alloy made of them. The first is the usual method and is the least troublesome and expensive ; but it does not usually give as sound, uniform, and strong castings of the alloy as the second. In the latter case, the metal of highest melting point is usually first fused and the others are added in the order of fusibility or volatility. The order of introduction into the crucible or melting-pot has an appreciable effect on the quality of the alloy. After the alloy has been made and poured into the ingot, or other mould, it may change in composition by the process of separation or " liquation," to which reference is elsewhere made, either by the denser metal settling out or by the change due to formation of other definite alloys of greater stability at various points in the mass, thus altering the com- position of the metal all around those points. Thus in gun- metal (bronze) the surface of fracture often has a variegated color due to separation of the tin and the production of a variable composition of alloy. This will be noted in the description of the behavior of many alloys made by the Author. It will be seen that the rapid cooling secured by the use of metal moulds is the best means of preventing this liquation. Slow cooling, affording ample time for the separa- tion and reconcentration of the constituents, and for the pro- duction of crystals, permits, often, very serious loss of quality. It will be noted that the best alloys are usually made most successfully when the molten metal is poured " sharp," L e. y hot, and then rapidly cooled to the point of solidification. The process of liquation is sometimes usefully applied, as in the Pattinson process of separating the metals in argentif- erous galena, or in cupriferous ores of lead. The desired alloy is very rarely made of its essential con stituents only. A simple binary alloy of copper and tin is, for example, rarely made in commercial work. Lead is often added to give color, zinc to cheapen it or to flux it, and some- times other metals to give special qualities. Statuary bronze usually contains some lead and zinc to give it its peculiar "patina"; bronze used in "hardware" and architectural 212 MATERIALS OF ENGINEERINGNON-FERROUS METALS. work, in bearings, etc., contains lead to give color and to make it wear well ; brass is hardened greatly, and strengthened, by the addition of one per cent, tin, or more, as in the " maxi- mum alloys " discovered by the Author. In such cases, the metal is added in small quantity to the mixture, after the latter is in fusion and alloyed. 135. Minute Quantities of Alloy often greatly influence the properties and quality of metals. Thus, it is stated* that lead alloyed with 0.003 per cent, of antimony turns percep- tibly freer than pure lead ; that an addition of 0.007 P er cent, copper unfit leads for use in the manufacture of white lead ; that gold containing 0.05 per cent, of lead exhibits greatly decreased ductility ; that copper containing 0.5 per cent, iron has but 40 per cent, of the conductivity of pure copper. Nickel is too brittle to work ; but, alloyed with o.i per cent, magnesium or 0.3 per cent, phosphorus, it can be rolled and worked. Brittle steel is sometimes made tough and malle- able by alloying it with 0.08 per cent, manganese or magne- sium. A difference of o.ooi per cent, in the amount of phos- phorus present in the best Swedish irons can be plainly observed by a change of malleability. 136. Art Castings in Bronze represent the most perfect work known in the department of foundry work. It has been practised from the earliest known and even pre-historic peri- ods, and the analyses of art castings found in the Egyptian tombs and in Nineveh prove that the composition then adopted was substantially that of the statuary bronze, and that of the art-work of to-day. The Greeks began to make bronzes several hundred years before the Christian era, and before the commencement of that era, had attained great skill in the art. The statue of Apollo, at Rhodes, made by the pupil of Lysippus, Chares, 330 B.C., was about 100 feet (30 metres) high, and after having been shaken down by an earth- quake some 60 years later, lay over 900 years prostrate, and was then carried away by a Jew who purchased it from the Saracens, making a load, as it is said, for 900 camels. The Chinese and Japanese first made use of bronze at some * Der Techniker, 1883. MANUFACTURE AND WORKING OF ALLOYS. 213 unknown but very early date. The art was long lost in Europe, but was revived in the i6th and i/th centuries, and now con- stitutes an exceedingly important industry. Art castings of large size are moulded and cast precisely as other brass-founding is done; but great precaution is taken in the selection of materials, in determining exactly the desired proportions and in all the details of foundry practice and manipulation. The usual mixtures are given elsewhere. In making statuary, the model is first formed, and is then lined cff by the founder in sections in such manner that each will be likely to be easily moulded and will " draw " readily ; plaster patterns are made of these sections separately, which are used in obtaining metal copies, which latter are finally joined together. Where the piece is to be cast whole also, the mould must be often made in many parts, in order that every section of the mould may be readily removed. In some cases, an elastic mould is made within which a wax model is formed, the latter being moulded in the sand in the usual manner. For such work, a plaster cast is usually first made, which is coated with any oily or glutinous substance which will not allow moisture to be transferred, and will not permit the adherence of the cope or mould, to be formed over it. By covering the model with a thin coating of wax, an outer mould can be constructed, and the inner and outer shapes may thus be separated by a thin space which represents that to be filled by the molten bronze, and determines the thickness of the casting. This space is often filled with wax and the latter is melted out when the mould is sent into the drying room or oven. Properly made, the mould has smooth, perfect sur- faces of the exact form to be reproduced, and the bronze, when removed from it, is an exact reproduction of the model, only requiring a small amount of work to make it marketable. If the composition and the work are what is desired, the sur- face of -.the casting is smooth, precise in form, sharp in out- line, and of good color. Statues thus made acquire, with age, a color or "patina" which distinguishes all good bronzes. Statuary bronze, and bronze for art- work generally, should have, when newly cast, a fresh, yellow-red color, and a fine 214 MATERIALS OF ENGINEERING NON-FERROUS METALS. grain, should be easy to work with file or chisel, very fluid when melted, taking the finest impressions of the mould, and when exposed to the atmosphere in the finished casting, should take the peculiar green patina characteristic of old bronze statuary of good quality. These qualities are not usually ob- tained in so high a degree in the copper-tin or copper-zinc alloys, the common bronzes and brasses, as in alloys contain- ing the three metals. According to Guettier, the best of these alloys are : COPPER. ZINC. TIN. 92 6 2 85 ii 5 65 32 3 It is very usual to add i or 2 per cent, of lead ; ancient bronzes contain as much as 6 per cent. According to Pliny, bronze was made by melting copper first, then adding 12^ per cent, of an alloy of equal parts tin and lead, known as plumbum argentarium. 137. Stereotype Metal, of which a good quality is made of 1 6 parts antimony, 17 parts tin, and 67 parts lead, is worked thus: The type is brushed over with a small quantity of black- lead and oil, placed in a casting-frame, and a cast taken in plaster of Paris. This cast is dried in a hot drying-oven until absolutely free from all moisture, and is held in form, meantime, by securing it to a flat cast-iron plate. The stereo- type metal is cast upon the matrix thus produced, and the plate thus obtained is planed up to a gauge and fitted to the press, or mounted on wooden blocks of the right height to work in the press. Damaged type are cut out and replaced with perfect ones. A later process is the following : * A sheet of tissue paper covered with printing paper is placed upon a perfectly smooth metal plate, and the two sheets are pasted together. These sheets are laid over the type, beaten into their in- terstices, covered with other sheets similarly beaten down, and * Spon. MANUFACTURE AND WORKING OF ALLOYS. 21$ this process is continued until the mass of paper forms a matrix of satisfactory thickness and strength. Heavier paper, as cartridge paper, is used for the last layers. This matrix is dried carefully between surfaces which hold it in shape, is then brushed over with French chalk or black lead, and laid in the casting box, where the stereotype metal is cast over it and a plate thus made. 138. German Silver is made by English founders of small bells and similar articles of copper 57, zinc 19, nickel 19, lead 3, tin-plate 2. The copper and nickel are fused together first, the zinc added after their fusion, and the other metals last. Commercial zinc containing lead is rarely pure enough for the finer grades of this alloy which do not permit the in- troduction of lead. It is difficult to obtain this alloy in correct proportions and of good quality. 139. Babbitt's "Anti-attrition" Metal is usually not cast directly into the " brasses " to be lined with it. It is made by melting separately 4 parts copper, 12 Banca tin, 8 regulus of antimony, and adding 12 parts tin after fusion. The anti- mony is added to the first portion of tin, and the copper is introduced after taking the melting-pot away from the fire, and before pouring into the mould. The charge is kept from oxidation by a surface coating of powdered charcoal. The " lining metal " consists of this "hardening," fused with twice its weight of tin, thus making 3.7 parts copper, 7.4 parts antimony and 88.9 parts tin. The bearing to be lined is cast with a shallow recess to receive the Babbitt metal. The portion to be tinned is washed with alcohol and powdered with sal ammoniac, and those surfaces which are not to receive the lining metal are to be covered with a clay wash. It is then warmed suffi- ciently to volatilize a part of the sal ammoniac, and tinned. The lining is next cast in between a former which takes the place of the journal and the bearing. Founders often prefer to melt the copper first in a plum- bago crucible, then to dry the zinc carefully and immerse the whole in the barely fluid copper. A report of a committee of the American Master 2 1 6 MA TERIA LS OF ENGINEERING NON-FERR US ME TA L S. Mechanics' Association, reporting on the use of Babbitt metal, state that thirty-five replies to their circular gave the following facts relating to the use of Babbitt metal : Four use gibs with Babbitt ; four use the solid octagon brass without Babbitt; seven use octagon with Babbitt; seven use half- round solid brasses without Babbitt ; four use half round brasses in three pieces with Babbitt, and one makes no re- port of the use of Babbitt. All, with one exception, report that the Babbitt metal should extend the entire length of the journal and should be put on in strips ^ to i^ inches wide, at a point between the top and the front and back points of the journal bearing ; one inserts it by drilling holes in the brass and then filling in with the metal. The Com- mittee have observed that, in engines of from thirty-two to thirty-five tons weight, the half-round brass does not give as good results as in lighter engines. Good results may be ob- tained from a hexagon-shaped brass if properly fitted. The Babbitt metal will wear until it is cut through into the cast- iron. The recess in the top of the brass is of advantage also as a reservoir for oil ; and as there is less bearing at that point, the brass wears away and the shaft beds itself into the brass, so that there is no lost motion or pounding between the shaft and the brass. The Committee is of opinion that the use of Babbitt metal is advisable. 140. Solders are alloys used in joining metallic surfaces, and parts of apparatus or constructions, by fusing them upon the surfaces of contact, and allowing them to cool, obtaining a more or less firm and tenacious union. They have a wide range of composition ; the " soft solders " are made of tin and lead ; " hard solders " are usually made of brass ; and special solders are composed of various alloys of copper, zinc, lead, tin, bismuth, gold and silver. Haswell's table of solders is given later. In soldering copper, brass, or iron with soft solder, a " soldering iron " is used to melt, and to apply the solder to the work. This instrument consists of a copper head, shaped somewhat like a machinist's hammer, the large end of which is inserted longitudinally in the claw-shaped end of an iron MANUFACTURE AND WORKING OF ALLOYS. holder, which is itself carried by a wooden handle ; it is heated in a small charcoal-furnace, or " brazier," which is especially constructed for the purpose. A " soldering fluid," usually a solution of zinc in hydro- chloric acid, is used to remove the oxide from the surfaces to be joined and to give them a coating of zinc, to which the solder will promptly adhere. Soldering is often successfully performed by cleaning the surfaces thoroughly, fitting them nicely together with a file, if necessary, placing a piece of tin-foil between them, binding them firmly together with " binding wire," and heating in the flame of a lamp or a Bunsen burner, or in the fire, until the tin melts and unites with both surfaces. Joints carefully made may be united, in this way, so neatly as to be invisible. When using the more fusible solders, as those containing bismuth, a fire is seldom needed. When one joint has been made with hard solder, it is not always safe to make another near it with the same composition ; a softer soldei; should then be used. Soft solders are not malleable, and where this quality is demanded, the solder is necessarily of the hard variety. An excellent solder for such work is made with silver and brass in equal parts. Coin silver, in thin sheets, is an excellent solder for cop- per, hard brass, and wrought iron. Cast iron cannot be readily soldered, and the attempt is rarely made. In making solders, great care is to be taken to secure uni- formity of composition ; they are often granulated by pour- ing from the crucible or ladle through a wet broom or from a considerable height into water, or they are cast in ingots and reduced to a powder by filing or by machinery. The silver and the gold solders are usually rolled into sheets ; the soft solders are generally sold in sticks, as is also pure tin ; those which are rich in tin are distinguished by their peculiar " tin- cry," which is destroyed by a very small admixture of other metals. In making solders, as all other such alloys, the most infusible metal is first melted, and the other constituents are added in the order of infusibility. OF THE UNIVERSITY 218 MATERIALS OF ENGINEERING NON-FERROUS METALS. fusible and are melted under tallow, and the hard solders are prepared under a covering of powdered charcoal to prevent oxidation. Yellow brass, containing from 65 to 80 per cent, copper, will be found useful at times in brazing wrought iron, mild steel, and all the common brasses and bronzes containing less than 10 per cent, tin or lead. Equal parts of copper and zinc make a good solder for yellow brass and is known as " broom " solder. Tin and lead are sometimes added, but probably without advantage, the one making the solder hard, the other weakening it. For brazing iron, yellow brass is excellent. In using these solders, the surfaces to be brazed should be well cleansed, sprinkled with borax, and bound tightly to- gether with fine iron wire. A clay " dam " around the joint is useful in confining the solder in place when melting. The heating should be gradual and the temperature brought slowly up to a red heat, occasionally adding borax, and, finally, the heat should be more quickly raised until the solder melts and fumes, when the piece is cooled. Silver and yellow brass make good solders for steel, melting at a moderately high heat and having considerable strength. Both solder and flux should be used sparingly to secure good work. Cast iron and alloys containing either tin or lead in considerable quantities cannot be easily soldered. The soldering fluid answers as a flux for soft solders ; borax is used with the hard varieties, as it dissolves the oxides of all metals thus treated, and leaves the clean metallic surface which is essential to perfect union. Sal ammoniac is often added to the soldering fluid when soft solders are used, and resin is a common, and in some respects the best, flux for tin- ner's work. Platinum is soldered with gold, and German silver with a solder of equal parts of silver, brass, and zinc. The essentials of a good solder are that it shall have an affin- ity for the metals to be united, should melt at a considerably lower temperature, should be strong, tough, uniform in com- position, and not readily oxidized. (See tables, pp. 221, 241.) 141. Standard Compositions are often adopted by en- MANUFACTURE AND WORKING OF ALLOYS. 219 gineers for the various purposes to which they apply the alloys. The tables hereafter presented are full of examples. In further illustration, we have the following as the compo- sitions adopted by the Paris, Lyons, and Mediterranean Rail- way of France : TABLE XXIX. STANDARD ALLOYS. i ATT fYV PROPORTIONS. TTO17O A .L.LU i Copper. Tin. Zinc. Lead. Ant. U bc*o* Gun- metal, i. 82 16 2 Bearings . 2. 84 U 2 . . Valves, Screws, etc. 3- 90 8 2 m Cocks, Whistles, etc. Brass, i. 70 3 . . Tubes. 2. 67 33 Stuffing-boxes, etc. 3- 65 35 . . Handles, Latches. 4- 63 37 . Plates, Washers. White metal. 5 71 24 Bearings. Packing " 14 76 10 Stuffing-boxes. Solder. 45 55 For tin plate. 40 60 ' ; ' zinc ' The useful alloys are, as already seen, exceedingly numerous, and are of extraordinary variety in appearance and physical qualities. They are applied to an almost equally wide range of uses. The following very complete lists will give an idea of their number, quality and applications.* * Chas. Haswell; Pocket-book, 1882. C. Bischoff : Das Kupfer und seine Legi run gen ; Berlin, 1865. P. A. Bolley: Recherches Chimiques ; Paris, 1869. A. Herve: Alliages Metalliques, Manuel- Roret ; Paris, N.D. 220 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XXX. ALLOYS AND COMPOSITIONS. HASWELL. . COPPER. u 2 N Z P NICKEL. LEAD. ANTIMONY. BISMUTH. SILVER. COBALT OF IRON. 1 [ ARSENIC. Argentan 55- 2 4 . 21. Babbitt's metal 3-7 84.3 75- 79 3 92.2 80 5.2 25- 6. 4 89. 10.5 7-3 Brass, common hard " mathematical instruments. " Pinchbeck 14-3 7 8 2O. " red tombac rolled 88.8 74-3 50. 88.9 II . 2 22 3 ^ 3-4 '8.3 " tutena r IQ. " very tenacious " white TO 80 IO " wire 67- 66. 33- 34- " yellow fine. Britannia metal tl when fused add... 25- 25- Bronze red ' 87 " red 8^ " yellow 67.2 80 31.2 1.6 u cymbals 1 gun metal, large small 90. 93- 7- 1.4 ' statuary i-7 Ch nese silver gc T o ,8 Chinese white copper Church bells 40.4 80. 69. 25-4 5-6 2.6 10. I %: 5 ,r 6 ' | 4-3 Clock bells .. 1-5 Clocks, musical bells *, - 12. 5 German silver 33-3 33-4 33-3 31-6 o 6 " fine 2 4 2.5 Gon-o's 8?. 6 18.4 23. 20. House bells Lathe bushes Machinery bearings 80. 87.5 hard 15.6 Metal that expands in cooling Muntz metal 75- 16.7 8-3 60 Pewter, best 86. 80 20 14. .... Printing characters Sheathing metal . . cV 80. 20. Speculum " 66. S. 66.6 12. Telescopic mirrors. 21. 29. 33-4 66.6 2 8: 4 4 .4 ( Mag ) Sal-a nesia.. mmon 69!' 4 iac 2 .4 5 ' Temper* iS.S 3reai Juicl n of clime tarta r6.'s 1-3 Type and stereotype plates " hard 7-4 69.8 73- 7-4 25-8 12.3 Oreide For adding small quantities of copper. MANUFACTURE AND WORKING OF ALLOYS. TABLE XXX. Continued. SOLDERS. 221 COPPER. 2 H LEAD. u 2 SILVER. BISMUTH. j CALCIMINE. ANTIMONY. Tin 2 S ye 58 ifi -6 IO " coarse, melts at 500 ~V\ 67 " ordinary, melts at 360 67 33 Spelter, soft 50 5 14 hard. . 67 , Lead 67 Steel 13 82 Brass or copper. . 5 Fine brass r * Gold 80 li hard 66 * " soft. 66 80 Silver hard 67 * * " soft 21 Pewter Iron 66 * " * " Copper FUSIBLE COMPOUNDS. COMPOUNDS. ZINC. TIN. LEAD. BISMUTH. CADMIUM. ... j 25 *9 12 25 33-3 3i 25 50 33 4 So 50 I Fusing at less than 200 33.3 Newton's fusing at less than 212 Fusing at 150 to 160 j .... 142. Special Recipes. The best bronze compositions for use in engineering are, according to Guettier,* the following : For pumps, bolts and similar pieces : Copper. Tin.. Copper 90 Tin.. 10 100 100 The latter is the softer of the two. Often from one to four per cent, of zinc is added, as already stated. * Guide Pratique ; Paris, 1865. 222 MATERIALS OF ENGINEERING NON-FERROUS METALS. For eccentric-straps and connecting-rod bearings : Copper 83 84 83 84 82 85.25 Tin 15 14 15 14 16 12.75 Zinc 2 2 1.5 1.5 2 2 Lead .. 0.5 0.5 .. 100 100 100.0 100.0 100 100.00 The addition of lead and increase of copper gives softer alloys. Lead is often used more freely than above. Locomotive driving-axle bearings : Copper 74 80 85.25 86 89 Tin 9.5 18 12.75 J 4 8 Zinc , 9.5 2 2.00 .. 3 Lead 7 .. 100. o 100 100.00 100 loo The Author prefers gun-bronze to either of the above. For Locomotive Slide Valves-* Copper phosphate 3.50 Copper 77.85 Tin n.oo Zinc 7.65 100.00 Connecting-Rod Brasses Copper phosphate 3.5 Copper 74. 5 Tin ii. o Zinc . ii. o 100. Axle-boxes No. i. No. 2. Copper phosphate 2.5 1.5 Copper 72. 5 73-5 Tin 8.0 8.0 Zinc 17.0 19.0 IOO.O IOO.O MANUFACTURE AND WORKING OF ALLOYS. 22$ Parts demanding greater strength Copper phosphate . 3. 5 Copper 85.5 Tin 8.0 Zinc , 3.0 100.0 Zinc is here added to the bronze to aid in securing that homogeneousness which is essentially the result of the ad- dition of phosphorus. For pistons (rarely needed) : copper, 89.75 ; tin, 2.25 ; zinc, 8. For car and locomotive axle bearings : Copper 80 79 86 89 Tin 18 18 14 2.5 Zinc 2 2.5 .. 8.5 Lead o. 5 IOO IOO.O IOO IOO.O For ordinary stationary machine journal-bearings : copper, 82 ; tin, 1 8. For whistles of locomotives and bells : Copper 80 81 78 79 78 71 Tin 18 17 20 23 22 26 Antimony 222 Zinc 6 .. Zinc 1.8 Iron 1.2 IOO IOO IOO IOO IOO IOO.O The last is the alloy of the famous " silver-bell " of Rouen. For pump-buckets, valves and cocks : Copper 88 88 86.8 Tin 10 10 12.4 Zinc 1.75 2 0.8 Lead 0.25 .. IOO.OO IOO IOO.O For hammers (for use on finished work) : copper, 98 ; tin, 2. This alloy will forge like copper; it may be hardened by adding more tin. 224 MATERIALS OF ENGINEERING-NON-FERROVS METALS. For wagon axle bearings : Copper. 78 Tin 20 Zinc.. 2 Copper. ... 25 Cast-iron 70 Tin 5 100 100 The best brasses may be taken, for general purposes, as accepted by good makers, as follows: For turned work : Copper 61.6 66.5 74.5 79.5 Zinc 35.3 33.0 25.0 20 Tin 0.5 0.5 0.5 0.5 Lead 25 i oo.o 100. o i oo.o 100. o The richer colors are given by the higher proportions of copper. The official recipe for work in French dock-yards is : Copper 65.80 76.0 85 Zinc 31.80 24.0 15 Tin 0.25 .... Lead 2.60 0.5 i 100.45 100.5 IQI The hardest compositions are used for the smallest pieces. These are used in the ornamentation of engines, for brass straps, for hinges, and for pulley-sheaves. Cheap alloys for bearings have been made of the follow- ing wide range of composition : Copper 56 5.5 58 Tin 28 19.5 28 Zinc 16 80.0 14 100 1000 100 The first Fenton's alloy is said to wear well, not to be specially liable to heating, and to be very durable. The last MargrafT's alloy is of similar quality. The second com- position is much cheaper and lighter, and takes the place of the white alloys used in bearings. MANUFACTURE AND WORKING OF ALLOYS. Other white metals for similar uses are : Copper 41 91 Tin 96 50 73 50 Antimony 8 5 18 5 108 56 100 56 The first is used for common bearings; the latter for small bearings carrying light loads. Still other alloys are : Tin ;, 18.0 Lead 32 85 4.5 Zinc 18 . .. 75.0 Antimony...., 50 15 2.5 100 100 100.0 The following are British (Woolwich) official recipes : Copper 20 6 7 8 10 Tin 2 i i i i Zinc i 23 7 8 9 ii which are used as hard as metals are desired. Kingston's metal, formerly much used for bearings, is made by melting 9 parts copper with 24 parts tin, remelting, and adding 108 parts tin, and finally 9 parts of mercury. An alloy of 90 per cent, tin, 8 per cent, antimony, and 2 per cent, copper has been found excellent for crank and con- necting-rod bearings on the Moscow and Nishni Railroad of Russia. On the Kursk-Charcow-Asovv Railroad an alloy of 78.5 per cent, tin, 11.5 antimony, and 10 copper is considered very superior for pivots of all kinds, slide valves, eccentrics, stuffing-boxes, etc. The Swiss Nordostbahn Company, in ordering locomotives recently, required the following prepa- ration as a composition for axle journals: 10 parts of anti- mony added to 10 parts of melted copper, with 80 parts of tin added, and the alloy run into bars, to be remelted for use. Bronze for bearings of axles, as made for the Great West- ern Railway of Great Britain, has been given the following 15 226 MATERIALS OF ENGINEERING NON-FERROUS METALS. composition : copper, 22 ; tin, 67 ; antimony, 1 1. French rail- ways have used copper, 82; tin, 18 ; and Italian roads have used an alloy of tin, 38 ; antimony, 25 ; and lead, 37, for a lining metal. The Perkins alloy for piston rings consists of copper 75, tin 25, and is used in steam engines worked at very high pressure without lubrication. 143. A Classified Table of the Alloys has been compiled, as follows, by Bolley,* from the works of BischofT f and other authorities, which presents the most complete compendium of the compositions used by the engineer and in the trades, known to the Author. This table is here given, omitting the alloys of the " precious " metals. TABLE XXXI. CLASSIFIED LISTS OF ALLOYS. Alloys of Copper. BRASS. RED BRASS. COPPER. ZINC. Pinchbeck . en -6 6.4 Q2. 5 7- 5 French Oreide QO. O IO O V w '" 8{.! 14 ^ 82 e./i 17 J.6 English " " . 86 38 13 62 Halberland alloy for imitation 87 o I^.O Mannheim gold, 0.62 per cent tin and 8q AA Q. 14 Tissier's alloy for buttons Q7 O 2 O Arsenic I . o Tombac common . . 71 ^ 28. * Arcet tombac, gilded 82 ^ 17- 7 Hegermuhle tombac, Paris 85. q 14-7 Red " " Q2 O * 80 " " Vienna 07 8 2 .2 Leaf " Ltiden<5cheid no IK 0.85 << < vv- A D 84.21 I5.7Q Bronze powder .... 81 o 16.0 Leaf bronze 84.6 15.4 " " (" gold ") Vienna 77 Q 22. 1 * Recherches Chimiques. Paris, 1869. | Das Kupfer und seine Legirungen. Berlin, 1865. MANUFACTURE AND WORKING OF ALLOYS. TABLE XXXI. Continued. YELLOW BRASS. 227 COPPER. ZINC. Malleable brass 70. 1 2Q Q " " Liidenscheid 72 T\ 27 27 Chrysorin 72 O 28 o Cominon brass 66 6 sa 4 Bobierre " Muntz metal 74 62 oe 08 " " low grade . en e 4O ^ 60 o og 2 Iron I 8 6s 4 -^4 6 " " low grade 6s s J2 ^ Lead 2 o 64 2 2-3 I Lead and tin 2 7 " ductile (Storer) S-l O 46 o Mecht's malleable brass 6c 24. ^4 76 6O. 26 7n 74 <> i< 66 o ^4 O Kessler's " " s8 ^ 41 7 Chrysorin Rauchenberger's 66.7 a-i . q Bristol brass 7< 7 24 ^ it 60 8 7.O Button alloy Liidenscheid 20 o 80 o Mallett " preservative of iron 2C 4 74.6 BRONZE-LIKE BRASS. Tombac Alloys. COPPER. ZINC. TIN. 80.0 I7.O a.o Golden bronze 80 Q7 9.06 O O7 " for ornaments "V* V/ 82.0 17.5 O. $ 228 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XXXI. Continued. Statuary Bronze. COPPER. ZINC. H LEAD. & NICKEL. ANTIMONY. The Shepherd Potsdam Palace 88 68 I 28 O77 I 6l 7 en I 21 o 18 Germanicus Potsdam 80 78 20 e 6 16 I ^ O. 27 Augsburg bronze ^. ^o 4-1 10 I "3O O "3O Nearly white soft 44 OO 4O QO 3 7O 81.20 1 .60 II.5O Britannia (Karmarsch) 6 30 2 JO go 10 O "lO " (Koller) 10 40 I OO 8=; 70 2 QO Pewter (leaf) 7.6o 1. 80 8q. 30 I. 80 < I 7O 6.80 84. 70 6 80 MANUFACTURE AND WORKING OF ALLOYS TABLE XXXI. Continued. 235 COPPER. TIN. ANTIM. ZINC. BISMUTH. Britannia (Karmarsch). . . . ' ' fine (Wagner) . . . Pewter often of . 3.60 0.81 i .60 85.00 85-64 Sl.^O 5-00 9.66 6 60 1.40 3.06 6 60 5-00 0.83 I 60 Alloys Principally Zinc. i COPPER. 1 TIN. ZINC. LEAD. Hamilton's alloy . - Garanci ! pt. dr. dr. dr. dr. oz. oz. dr. dr. Black - i Dark grav * a 26 Green-gray 27 X Red boil. 28 r jj 4 j Copper color. Plates so c A *. Copper color with agitation X Purple boil 145. Lacquering is the process of covering a polished surface of brass or of other metal with a transparent or trans- lucent coating, which, while protecting it from oxidation and * Made to the consistency of cream. 240 MATERIALS OF ENGINEERING-NON-FERROUS METALS. discoloration, does not wholly conceal it. It is a process of varnishing polished metal. It is applied also to the surfaces of bronzed objects. Lacquer is a solution, usually, of some vegetable gum or resin in alcohol or other effective colorless solvent. In its application, great care is taken to keep the piece to be lacquered warm and of uniform temperature, to apply the solution quickly, smoothly and uniformly. The usual solution is " shellac " in alcohol, and the best can, as a rule, be made with the " stick " lac. It may be colored by any permanent transparent alchoholic solution giving the desired tint. The red coloring matters are, usually, dragon's blood, red saunders or annotto ; the yellow are gamboge, sandarac, saffron, turmeric or aloes. The following is Graham's table of lacquers : TABLE XXXIII. LACQUERS. SOLUTIONS. REDS. YELLOW. V a fj I Q J | u J3 V 1 > % -o jrt O *rt ? J ^ 4) *x d No Shellac. d s Canada B Spirits of Pyro-acet Spirits of Turpentir a , STRENGTH OF NON-FERROUS METALS. 2$$ being taken, this coefficient is here called the Modulus of Resilience. When the energy of a striking body exceeds the total re- silience of the material, the piece will be broken. When the energy expended is less, the piece will be strained until the work done in resistance equals that energy, when the striking body will be brought to rest. As the resistance is partly due to the inertia of the particles of the piece attacked, the strain-diagram area is always less than the real work of resistance, and, at high ve- locities, may be very considerably less, the difference being expended in the local deformation of that part of the piece at which the blow is received. In predicting the effect of a shock it is, therefore, necessary to know not only the energy stored in the moving mass and the method of variation of the resistance, but also the striking velocity. To meet a shock successfully it is seen that resilience must be secured sufficient to take up the shock without rupture, or, if possible, without serious deformation. It is, in most cases, necessary to make the elastic resilience greater than the maximum energy of any attacking body. Moving Loads produce an effect intermediate between that due to static stress and that due to the shock of a freely mov- ing body acting by its inertia wholly ; these cases are, there- fore, met in design by the use of a high factor of safety, as above. As is seen by a glance at the strain-diagram, ff (Fig. 2), the piece once strained has a higher elastic resilience than at first, and it is therefore safer against permanent distortion by moderate shocks, while the approach of permanent extension to a limit renders it less secure against shocks of such great intensity as to endanger the piece. When the shock is completely taken up, the piece recoils, as at e*f"f" 9 until it settles at such a point on that line as- suming the shock to have extended the piece to the point e* that the static resistance just equilibrates the static load. This point is usually reached after a series of vibrations on either side of it has occurred. With perfect elasticity, this 254 MATERIALS OF ENGINEERING NON-FERROUS METALS. point is at one-half the maximum resistance, or elongation, attained. Thus we have WV* = . ..... (.o) but/ varies as x within the elastic limit, which limit has now risen to some new point along the line of normal elastic limits, as e vi . Taking the origin at the foot of/'/", since the variations of length along the line Ox are equal to the elongations and to the distances traversed as the load falls, and as stresses are now proportional to elongations, p=ax\ Wh=Ws;mdW=P . . . (u) when the resisting force is/, the elongations x, while h and s are maximum fall and elongation, and P is the maximum resistance to the load at rest. Then f* f* / dx=a x dx J a J -s 2 =Ws.:s= (12) 2 a For a static load, if s' is the elongation, W lV=P=as' /. y- . a Hence, and the extension and the corresponding stress due to the sudden application of a load are double those produced by a static load. Where the applied load is a pressure and not a weight, z.e.j where considerable energy in a moving body is not to be absorbed, as in the action of steam in a steam engine, the only increase of strain produced by a suddenly applied load is that produced by the inertia of such of those parts of the mass attacked as may have taken up motion and energy. STRENGTH OF NON-FERROUS METALS. 255 155. Proportioning to Resist Shock. The problem of proportioning parts to resist shock is thus seen to involve a determination of the energy, or " living force," of the load at impact, and an adjustment of proportion of section and shape of piece attacked such that its work of elastic or of ultimate resilience, whichever is taken as the limit, shall exceed that energy in a proportion measured by the factor of safety adopted. For ordinary live loads and moderate impact, re- quiring no specially detailed consideration, the factors of safety already given (Art. 148), as based upon ultimate strength simply, are considered sufficient ; in all cases of doubt, or when heavy shock is anticipated, calculations of energy and resilience are necessary, and these demand a com- plete knoVvledge of the character, chemical, physical, and structural, of every piece involved, of its resilience and method of yielding under stress, and of every condition in- fluencing the application of the attacking force in other words, a complete knowledge of the material used, of the members constructed of it, and of the circumstances likely to bring about its failure. The form of such parts should usually be determined on the assumption that deformation may some time occur, and such expedients as that of Hodgkinson in enlarging the sec- tion on the weaker side, as well as the adoption of a larger factor of safety based on ultimate strength, are advisable. 156. The Methods of Testing and the construction of the machines used are fully described in Part II. of this work. The form of test-piece advisable, and standard formulas, and many facts relating to this part of the subject may be there studied, or in works on the strength of materials. 157. Compression. Resistance to Compression is measured by the same process as in testing by tension. This form of resistance is, however, governed in many cases by different laws, and is often modified by the size and shape of the piece tested to even greater extent than is resistance to tensile stress. The method of rupture is not only different for differ- ent materials, but it is different with pieces of the same metal for every difference in size, shape, or proportion. Thus, a 2$6 MATERIALS OF ENGINEERING NON-FERROUS METALS. piece of copper or lead is soft and tough, and, in the form of a short cylindrical column, will gradually yield by crushing until it assumes the form of a cheese, or a button; the same metal in longer cylinders will yield similarly, until, reaching a certain limit, as in long columns, it will yield by bending laterally, and under a comparatively small load. A piece ot speculum metal, or of other brittle metal or alloy, will break by crushing into fragments, and will break up the more com- pletely as it is harder and more brittle. Extremely hard metals and alloys exhibit no sign of yielding until their limit of resistance is reached, when they suddenly fly to pieces with great violence. In all cases, resistance increases up to a limit beyond which the piece usually gives way suddenly, if the metal be hard or brittle ; while ductile and malleable metals often offer constantly increasing resistance, the limit being reached only when the pressure becomes so great as to cause the metal to flow steadily, as is illustrated in the manufacture of lead Pipe- In consequence of these variations due to form and size, it is even more necessary than when testing by tension to have a standard form of test-piece, as proposed in Part II., and to report all observations as made upon such standard. 158. The Structure of the Piece and its Chemical Com- position determine the compressive resistance of metals and alloys. With pure, well-worked metal, the resistance follows pretty closely a law peculiar to and characteristic of each metal. Within the elastic limit, the behavior of the piece may be taken as the same, whether under tension or compres- sion ; beyond that limit, the compressive strength usually ex- ceeds the tensile in a proportion which varies greatly. Copper and other non-ferrous metals are rarely used in the form of columns. Should it be necessary to so use them, the formu- las given in Part II. and in special works on strength of ma- terials may be used, substituting the proper value, C, of the modulus for compression. 159. The Transverse Strength, or the resistance of any piece to bending, is determined by the longitudinal strength STRENGTH OF NON-FERROUS METALS. 257 of the metal, both in tension and compression, by the form of the piece, and by its absolute dimensions. When this method of stress affects a bar of metal, there is called into action at every section a set of forces resisting flexure, each acting about a u neutral line " at which the forces change sign. If a bar is placed in the testing machine, and if, while supporting it at each end, the machine is made to apply a depressing force at the middle of the piece, the upper part of the bar is compressed, and the lower extended ; while be- tween these portions of strained metal is a plane of unstrained material, whose trace on the vertical plane is the neutral line. The moments of the forces by which the bar resists compres- sion above and extension below this plane, together produce the measured resistance to flexure. The position of the neu- tral plane is determined by the relation existing between the magnitudes of the two forms of resistance ; it may be con- sidered as always at the middle of the section, within the elastic limit, while beyond that limit it approaches that side at which resistance is greatest at the moment. The total resistance to flexure, then, is measured by the sum of these two moments of resistance, which are themselves measured each by the product of the mean resistance of the strained parts of the most severely loaded cross section affected by it into its own lever arm. By the ordinary theory, and its resulting equations, the resistances of particles to compression and to extension are taken proportional to their distance from the neutral surface ; this is correct up to that limit of flexure at which the exte- rior sets of particles on the one side or on the other are forced beyond the elastic limit. With absolutely non-ductile materials, or materials destitute of viscosity, fracture occurs at this point; but, with nearly all of the metals and alloys in common use, rupture does not then take place. The exterior portions of the mass are compressed on the one side, offering more and more resistance nearly, if not quite, up to the point of actual breaking, which breaking may only occur long after passing the elastic limit ; on the other side, similar sets of particles are drawn apart, passing the elastic limit for tension, 17 258 MATERIALS OF ENGINEERING NON-FERROUS METALS, and then resisting the stress with a more nearly constant force, " flow " occurring until the limit of that flow is reached, and rupture takes place. No expressions have yet been derived by analysis, and constants determined by experiment, which enable the engi- neer to express by an equation the actual method of varia- tion of internal resistances with variation of load and of de- flection, for all materials ; but sufficient accuracy is usually obtained for practical purposes by treating the case in the simplest manner. 160. Methods of Distribution of Resistances, in cases of flexure, are exhibited in the accompanying figures. FIG. 3. FLEXED ELASTIC BEAM. In MN, the material being perfectly elastic up to the limit of flexure, the stress at any point is proportional to the area of the element strained, to the maximum elastic resist- ance of the material, and to the distance x of the element from the neutral plane MON. The resistance to flexure within the range of perfect elasticity is, therefore, in this case, as when the beam is ruptured, at that limit proportional to the breadth of the piece and to the square of the depth, where the section is rectangular. Where a metallic beam is strained beyond the elastic limit at any part of its sec- tion, the stress outside that part is more nearly con- stant, and may become equal to the maximum re- .r IG. 4* sistance of the material, or nearly so. Thus, in Fig. 4, the law of resistance changes at a and is no longer proportional to the distance of the STRENGTH OF NON-FERROUS METALS. 259 strained particles from the neutral plane, but has the maxi- mum possible value. This change may occur abruptly, as shown, or gradually, making the shaded parts exhibiting the magnitude of the stress a pair of parabolas placed vertex to vertex. Finally, with all perfectly ductile M ' materials, all parts of the section become equally strained, nearly as in Fig. 5. 161. Theory of Rupture.* In the usual case, in which the resistance to distortion varies from a maximum, R, at the outer surface to zero on the neutral plane, as in brittle ma- terials, we have for the elementary area dy dx, for the resist- /? /? ance y per unit of area, and y dy dx on the area dy dx ; Ct j w, while the moment of resistance, M, on that part of the whole section which lies on one side the neutral plane is obtained by integration from that line to the most strained fibre on that side, at a distance d v R being the " Modulus of Rupture " : R r aj *>., the quotient of the modulus of rupture by the distance of the most strained fibre from the neutral line, multiplied by the moment of inertia of the section considered. When the resistance, after passing the elastic limit, be- comes throughout equal to the maximum R, we have per unit of area, a resistance R dy dx, and for the moment ft tdl R\ , y dy Jo Jo = M'. For rectangular beams, when the neutral line may be taken at the middle of the section, as with non-ductile ma- terials generally for the first, and for copper, tin, lead and * See Wood's " Resistance of Materials " for the Theory of Resistance. 260 MATERIALS OF ENGINEERING NON-FERROUS METALS. other substances having nearly equal values of T and C, for the second case, we get, for the two cases respectively : (a) M=\Rbd 2 \ (b) M* = b being the breadth, and <^= 2*/ r the total depth of section. Thus, assuming the same value for ultimate resistance of cohesion, the ductile substance offers one-half greater resist- ance than the non-ductile, and one-half greater resistance just beyond than just within the elastic limit. Hence, also, it can only be expected that the value of R will coincide with the resistance to direct tension or direct compression in rare cases. It is evident that the actual value of R may be com- pared with the values of T and C, to determine to what extent the case approaches that giving the second of these equations. The first of these cases is that which it has been custom- ary to assume as applicable in all cases. Its solution evi- dently gives results differing from the truth on the right side. Examining the equation, it is seen that the moment of re- sistance, M } is measured by the product of the " modulus " of rupture, R, into the quantity y 2 dy dx divided by the depth di to the neutral line, or as, shown by M. Navier, to the axis through the centre of gravity. The quantity y 2 dy dx, which is always a factor in this expression, is the " moment of inertia." The data to be here given are experimentally obtained figures, derived from tests of pieces of rectangular section ; other forms will be considered later. 162. Formulas for Transverse Loading are deduced in all works on resistance of materials. For cases of rupture, when the beam is supported at the ends and loaded in the middle, for rectangular bars, -P/= ]?Rbd* ; and R = 4 6 2bd STRENGTH OF NON-FERROUS METALS. 26l for non-ductile materials, and it may be assumed, in all cases in the engineer's practice, that the material tested is in prac- tice either sufficiently elastic and rigid to justify the use of this formula, or is to be loaded only within its elastic limit. Then the formulas for other cases become : (i.) Beam fixed at one end, load at the other : Pl=~Rbd 2 -, p=LRML. o o / (2.) Same, with load distributed uniformly: (3.) Beam supported at ends, loaded at middle : Lpl=M, P= 2 -R^. 4 3 / (4.) Same, uniformly loaded : l -Wl=M; '=!*. (5.) Beam firmly fixed at ends, loaded at middle ^-.jr; P-*R. Same determined by Barlow's experiments : I/y=J/; P=R*. O / (6.) Same uniformly loaded : Wl-M\ 12 262 MATERIALS OF ENGINEERING NON-FERROUS METALS. (7.) Fixed at one end, supported at the other, load at the middle: All of these equations are, of course, "homogeneous." Replacing bd 2 by 0.59^, transforms these quotations so as to apply very exactly to circular sections. 163. The Modulus of Rupture, R, being obtained by experiment and inserted in these formulas, the maximum load that a beam will support, when of similar shape and of that material, becomes calculable. The value of the modulus of rupture is readily deter- mined by experiment from the formula : when the weight of the beam, W, is taken into account. When the dimensions all become unity, we have, neglecting W, P 3 p. 2 ' that is to say, the modulus of rupture is one and a half times the load which would break a bar unity in length, breadth and depth, supported at the ends and loaded in the middle. For British measures, it is 1 8 times the weight that would break a bar so loaded if one foot long, and one inch square in section. Very ductile bars bend without breaking. The correct modulus of rupture in these cases, therefore, cannot be de- termined, and it is necessary to assume a given amount of bending as equivalent to breaking the bar or rendering it useless, and the modulus of rupture is calculated from the load causing this maximum deflection, to afford a means of comparing the transverse strengths of all bars which were tested. STRENGTH OF NON-FERROUS METALS. 263 164. The Theory of Elastic Resistance, as generally ac- cepted, is as follows : In figure 6, which represents a longitudinal section through a loaded beam, let Fbe the neutral line extending through- out its length. Let AB and CD be consecutive transverse sections separated by the dis- tance dx ; C'D' is the position of C when swung out of its original place by the action of the load W, and its intersection with the plane AB is found at R. Then, ab being the original length of any fibre at a dis- tance Ob y l from the neutral axis, bc \ will be its elonga- tion, and if the radius of curvature, OR, is called p, we have i ydx A___; A C C a b F E- <5 ..'/ o- - 9,0-1 I FlG 6 and the stress on any fibre of the area, a dy dz, since iE::\idx 9 will be a and the moment about the intersection with the neutral line is accordingly as the fibre is above or below that line. The total moment will be E ( b ( d * E ( b \ d2 = \fdjd* + \ fdydz. P Jo Jo P Jo Jo For cases in which the section is symmetrical about the neutral line El E [ b (+x d '= = - y*dy dz t P PJoJ-kT/ ' ., M 264 MATERIALS OF ENGINEERING NON-FERROUS METALS* in which integrals b is the breadth of section, */, and d 2 are the depth of the half sections above and below EF, and d is the total depth. Also, The value of p, the radius of curvature, is shown in works on the differential calculus to be p= dx* which value reduces the equation for M PI, as in Fig. 6, to when ~j may, as is probably usually the case, be neg- CLsv lected. Inserting the value of M in terms of x, we have, for ex- ample, with the " cantilever," or beam fixed at one end, loaded at the other, origin at the fixed end : , which, being integrated once, gives where x = O, -- = O, and C O. Again integrating, and STRENGTH OF NON-FERROUS METALS. 265 in which, where x = o, y = O and C = O, and the value for deflection at x = /, for this case is D - w as already given. For uniform loading, and All usual cases are developed in treatises on the theory of the resistance of materials. The elastic resistance to flexure is of greater importance in very many cases than the ultimate transverse strength, as pieces are in machinery almost invariably, and in other struct- ures usually, rendered useless when the change of form ex- ceeds a limit which is generally intended to be well within the elastic range. In some of the tables, the figures in the column headed " Modulus of Elasticity," are those which are considered the most probable moduli within the elastic limit, or which most nearly represent the relation between the stresses and the distortions within that limit. In a few instances the apparent modulus at. the beginning of the test is much smaller than it soon afterward becomes; and this indicates either a possible error or the existence of internal stress at this part of the test. In general, we have, within the elastic limit, ~ for the case of a beam fixed at one end and loaded at the other. 266 MATERIALS OF ENGINEERING NON-FERROUS METALS. When uniformly loaded, ~ 8 El ' /3 For beams supported at the ends, these equations for single and distributed loads are i_PP_ t " ' 48 / ' / 3 For beams fixed at the ends, we have I P/3 20oDf D - -=-=: , nearly ; P = -- n 200 El / 3 For rectangular beams, and we may write the simplified formula for a beam sup* ported at the ends and loaded in the middle, For a beam fixed at one end and loaded at the other, \6aPl* M, '' and, when uniformly loaded, the t o cases give and STRENGTH OF NOX-FERROUS METALS. 267 Where the length is measured in inches, i 1728 a = , and when in feet, a = ' 165. The Torsional Strength and elasticity of iron and steel have been less thoroughly investigated than either of the other forms of resistance. The moment of the applied force, as measured by the product of the magnitude of that force into the length of its lever-arm, at each instant equilibrates the resistance, and the formula for elastic resistance becomes: r, ,, 2ns f r i , Fl M r 3 dr. For solid cylinders, Fl= M = 1.5708^ = 0. For hollow cylinders, r =M= i. 5708.9 -' , I where F is the applied force, / its lever-arm, M its moment, s the resistance of the material on the unit of area, or the maximum stress, r and r T are the radii of the shaft, internal and external, and d and d^ are the diameters. The angle of torsion is proportional to the length of the part twisted and to the torsional moment. The formula giving its value is 2Mx _ T>2M x _ Fix -~~'"~"~- 2 ~ x being the length of the part twisted ; I-/ Ttjr ^^^i 4 ns-l Fl=M=aC~ = Q.ooSC - -, 32* x in which formulas C is the coefficient of elasticity of torsion. 268 MATERIALS OF ENGINEERING NON-FERROUS METALS. 166. The Strength of a Metal Shaft depends not only on the magnitude of the ultimate resistance of the mate- rial, but upon the method of its action. With brittle mate- rials, fracture must occur when the limit of resistance of the outer layers is reached ; with ductile metals, capable of flow, fracture may not take place until all, or nearly all, parts of the cross section have been highly strained, the outer portions yielding by flow until the inner parts have been strained to their maximum. For the first case, we have for the area of each elementary S T ring, 2nr dr, for the stress upon it s = , and for its lever- '"i arm, r. Then for hollow shafts, and when r = O, d = O, as for solid shafts, Fl= M 1.5708 s l r^ = 0.196 s^*. To obtain the diameter, we have : For solid shafts, For hollow shafts, 3 d, = In these formulas, the ultimate resistance may be taken as already given for tension, and the factor of safety should usually be large. When the material is capable of flow to such an extent that the whole section resists with maximum effect, we have STRENGTH OF NON-FERROUS METALS. 269 the elementary area as before 27trdr, its lever-arm r, and the value of s becomes constant and equal to 5,. Then Fl = 27TS, \ ri r*dr = - ns 1 (r? - r 3 ) = 0.26s, (d, - d ), J ro 3 and when r = O, Fl= o. In such cases, therefore, the strength of the shaft is in- creased one-third by the ductility of the metal.* It is uncer- tain to what extent this action occurs, and it is still more uncertain to what extent the action here occurring is a true shearing action. The last set of formulas, above deduced, are rarely used by the engineer. When the section is square, the resistance is increased about 40 per cent, above that of a circular section having a diameter equal to the side of the square. The real condition of the metal under stress is undoubt- edly always intermediate between the two cases above taken, the metal near the centre resisting as a solid shaft strained within the elastic limit at its outer bounding surface, while the external portion acts as a hollow shaft strained through- out beyond that limit. Assuming the latter to be strained to the maximum throughout, and taking r l r 2 as the radii of the two parts, the total resistance would be- * First shown by Prof. Jos. Thomson (Cam. and Dub. Math. Jour., Nov., 1848; Ency. Brit., Art. Elasticity, pp. 798-9, 1883); his paper was not dis- covered by the Author until he had himself determined the facts experimentally, had reconstructed the theory as above, and had applied it, further, to the case of bent beams, as in Art. 161, and in Part II., Arts. 262-3, 277. 2/O MATERIALS OF ENGINEERING NON-FERROUS METALS. If a e and a r are the angles of torsion at the elastic limit of the piece and at the beginning of rupture or of flow, and If a e = a r , M= \7tsr*, as already shown for brittle sub- stances. When a e = o, as in absolutely inelastic materials, did such exist, or when ot r = oo , as with perfectly ductile sub- stances, M= %7tsr 3 , as already deduced for substances capable of unlimited flow. When the torsional moment is given, the diameter of a shaft in inches is given by Molesworth as in which d diameter in inches. / = lever-arm in inches. P=. twisting effort in pounds. VALUES OF K. Wrought iron 1,700 Copper 380 Tin 220 Gun bronze 460 Brass 425 Lead 170 167. The Tenacity of Copper varies very greatly with physical and chemical modifications of structure and com- position. In the ingot, if pure, it is generally stronger than in masses re-cast, as it is peculiarly liable to injury by the absorption of oxygen, the production of " blow-holes," and the formation of oxide. Rolled and forged copper are STRENGTH OF NON-FERROUS METALS. 271 stronger than ingot metal. They are made from well-fluxed ingots and are strengthened, like all rolled or forged metals, by working. Drawn copper is still stronger, and its strength increases as the wire is smaller. Major Wade * found the tenacity of Lake Superior cast copper to range from 22,000 to nearly 28,000 pounds per square inch (1,547 to 1,968 kilog. per sq. cm.), averaging above 24,000 pounds (1,705 kilogs.). Egleston gives the tenacity of both Lake Superior and Ore Knob (N. C.) copper as above, 30,000 pounds per square inch (2,109 kgs. per sq. cm.). Anderson f gives the figures for the tenacity of copper, which, in round numbers, are as below ordinary copper is compared with that fluxed with phosphorus : TABLE XXXIV. TENACITY OF COPPER. PHOS. TENACITY, T. Lbs. per sq. in. Kilog. per sq. cm. 34000 19,000 25,000 38,000 45,ooo 48,000 50,000 2,390 1,336 1,758 2,671 3,164 3.374 3,515 cast forged O.OI5 0.02 O.O3 O.O4 t( The effect of fluxing with phosphorus is here very plainly shown and amounts to an average increase of tenacity of 4,000 pounds per square inch (2,812 kilogs. per sq. cm.) for each one per cent, added up to four per cent. 168. Cast Copper. The following are the records of tests, made by the Author, of ingot copper and of copper castings made direct from re-melted ingot: * Metals for Cannon, 1856. f Strength of Materials. 2/2 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XXXV. TESTS OF INGOT COPPER. No. 654 a ; length 5", diameter 0.798" ; sound. LOAD J LBS. EXTENSION, INCH. LOAD ; LBS. EXTENSION, INCH. 500 O.OOOg 7,000 0.627 1,000 0.0038 8,000 0.941 2,OOO O.OOSg 120 o . 0964 3,000 0.0137 9,OOO 0.1507 4,000 O.O2O5 IO,OOO 0.2122 I2O 0.0089 120 O.2OO9 5,000 O.O279 I2,OOO 0.3686 6,000 0.0324 1 2O 0-3551 1 20 0.402 13,000 broke. Tenacity 26,000 Ibs. per sq. inch, original area. 1,828 kilogs. " " cm. " 30,398 Ibs. " " inch, fractured. " 2,137 kilogs. " " cm. No. 654 b, same as above. LOAD. EXTENSION, INCH. LOAD. EXTENSION, INCH. 500 0.0004 IO,OOO 0.1388 1,000 O.OO32 I2O 0.1317 4,000 O.O2OI T 2,OOO O.3O2O 1 20 0.0037 120 0.2933 7,000 0.0485 14,910 broke. Tenacity 29,820 Ibs. per sq. inch, original area. 2,096 kilogs. " " cm. " 36,217 Ibs. " " inch, fractured. " 2,546 kilogs. " " cm. ' 169. Tests of Copper. The methods of test adopted by the Author in testing these materials are also illustrated in the table of results which follow. The figures given ex- ceed those obtained from similar metal by Major Wade. STRENGTH OF NON-FERROUS METALS. 2/3 These records are taken from the records of tests made for the Committee on Alloys of the U. S. Board. The tests were made on bars cast from re-melted ingot copper. TABLE XXXVI. TESTS OF CAST COPPER. No. 30 A. Material : Lake Superior copper, cast in iron mould. Dimensions : Length, 5" (12.7 cm.) j diameter, 0.798" (2 cm.). H 10 j, . H MI , 1 Z u < 2 - - K - 1 D ^ 2 O O H z - - H S ||S ii 11 ft Q a z ** 2* ^* Q Q z - Z ^ ^ 1 M H | s 3 H Pounds. Pounds. Inch. Pounds. Pounds. Inch. 400 800 0.0004 .00008 11,000 22,000 0.1605 .03210 1,000 2,000 O.OOII .00022 12,200 24,400 0.2191 .04382 2 COO 4,000 0.0022 .00044 14,000 28,000 0.3258 .06516 4,000 6,000 8,000 12,000 O.OC27 0.0032 .00054 .00064 2 7 14.400 540 28,800 Set 0.3155 0.3448 ^8-6" 6,400 6,800 7,200 12,800 13,600 14,400 O.C052 0.0083 0.0132 .00104 .00166 .00264 14,600 Broke y& A end. F 29,200 st as readir ractured se 0.3760 .07520 g was taken # inch from ction distorted from cir- 8,000 8,800 9,600 9,800 250 10,200 16,000 17,600 19,200 19,^00 500 20,400 0.0358 0.0642 0.0942 0.1073 Set 0.0951 0.1218 .0^.716 .01284 .01884 .02146 cular form. Three diameters measured 0.737 inch, 0.725 inch, and 0.732 inch. Tenacity per square inch original section, 29.200 pounds (2,053 kilogs. per sq. cm). Tenacity per square inch fractured section, 34,790 pounds (2,446 kilogs. per sq. cm.). 02436 No. 525 a ; length, 6" ; diameter, 0.798" ; sound casting. NO. LBS.; LOAD. EXTENSION, INCH. 1 NO. I.BS.; LOAD. EXTENSION, INCH. 3,470 0.01 5,900 0.07 4,240 0.02 6,780 0.12 4,920 0.03 7,220 0.16 5,350 0.04 7,270 broke. Tenacity 14,540 Ibs. per sq. inch. " 1,022 kilogs. " " cm. 274 MATERIALS OF ENGINEERING NON-FERROUS METALS. No. 525 b ; size as above ; sound. NO. LBS.; LOAD. EXTENSION, INCH. NO. LBS. J LOAD. EXTENSION, INCH. 4,OOO 0.01 8,100 0.23 4,900 O.O2 g.OOO 0.30 5,100 0.03 IO,OOO 0.40 6,2OO O.II 10,220 broke . 7,550 0.17 Tenacity, 20,646 Ibs. per sq. inch. 1,451 kilogs. " ' 4 cm. No. 57 B. Material : Copper cast in iron mould. Dimensions : Length, 5" (12.7 cm.) ; diameter, 0.798" (2 cm.). W 10 z 2 x W K < 10 Z 2gx D end. Inch. .0016 .0032 .0048 .0113 .OI 7 1 .C275 C372 .C2 5 8 .0485 .0^81 ,o<46 .0710 0743 )4 inch from fractured section i inch from fractured section 2 in r hes from fractured section 3 inches from fractured section 4 inches from fractured section 4^ inches from fractured section 5 inches from fractured section 6 inches irom iraciured section 6> 2 mcnes from fractured section 0.40 The importance of effective fluxing and of skill and care in melting and casting copper, are well shown by a compari- son of the figures given above for ingot copper with those obtained for the several re-cast samples, and even better by contrasting the figures obtained for the latter with those to be given for rolled and drawn copper, which may be taken to represent the most perfect attainable soundness. Rolled Copper as tested by the Author, in bars pur- chased in the market, had a tenacity of 32,000 pounds per square inch and reduced in section 40 per cent. Two samples from the same bar gave the same figure. Rolled copper has been tested by a committee of the Franklin Institute * who * Journal of the Franklin Institute, 1837. 276 MATERIALS OF ENGINEERING NON-FERROUS METALS. found that the mean of over 60 experiments gave a tenacity of very nearly 33,000 pounds per square inch (2,399 kilogs. per sq. cm.), the variations amounting to from 2 to 5 per cent. Rolled copper, tested by Bauschinger, exhibited tenacities varying from 29,000 to 32,000 pounds per square inch (2,663 to 2250 kilogs. per sq. cm.), with a reduction of section, at fracture, of 30 to 45 per cent. Several authorities agree on nearly the following figures for various commercial forms of copper: TABLE XXXVIII. TENACITY OF COMMERCIAL FORMS OF COPPER. LBS. PER SQ. INCH. KILOGS. PER SQ. CM. Copper cast . . 24 ooo I 434 ' ' forged . .... M.ooo 2,1^7 " bolt 36,000 2,151 " sheet . 36,000 2,1^1 62,000 4,2^2 Major Wade found the tenacity of " L. S." copper used in making U. S. ordnance to be from 24,000 to 25,000 pounds per square inch (1,688 to 1,758 kilogs. per sq. cm.), and that of other brands to be between 20,000 and 21,000 (1,463 kilogs.), increasing a little with hammering. The density varied between 8.523 and 8.757, the higher figures accompanying, usually, high values of T. According to Trautwine, the strength of cast copper varies from 18,000 to 30,000 pounds (1,265 to 2,109 kilogs.), a range fully confirmed, as above, by the experiments of the Author. Bolt copper ranges from 25,000 to 40,000 pounds per square inch (1,758 to 2,812 kilogs. per sq. cm.), and wire is the stronger as it is drawn finer and harder, to an extent not yet well settled by experiment. Wertheim obtained for the tenacity of hard wire 4,100 STRENGTH OF NON-FERROUS METALS. 277 kilogs. per square centimetre of section (58,250 pounds per sq. in.), with an elongation of 0.0033, and for the same wire, annealed, 3,160 kilogs. (44,900 pounds), with an extension of 0.003. Copper steam pipes are sometimes given a thickness / = 0.00148 n d + 0.16,* nearly ; or, according to some authorities,f / = 0.0001 dp + 0.125, when t is the thickness in inches, n the number of atmospheres pressure, d the inner diameter, and / the pressure in pounds per square inch. Feed pipes are a little heavier. 170, Shearing Stresses for Copper and sheet brass are given by the Ordnance Bureau of the United States War Department \ as below : TABLE XXXIX. SHEARING OF COPPER AND BRASS. Punching. DIAME- TER OF PUNCH. PRESSURES. THICK- NESS OF SHEET. PRESSURES. Circ. hole i in. diam. IRON. Brass, .os inch thick. Copper, . 15 inch thick. Iron, .105 inch thick. Copper. Brass. Thick- ness. Pressure, Circ. hole i in. diam. In. 1.5 1-375 1.25 I.O .Q .8 :i 5 4 3 .2 Lbs. 8,475 7.723 6,980 5,450 5.092 4.332 5.772 3,267 2,635 2,:8 3 -,673 1,110 Lbs. i5,99 6 14,570 13-275 ",073 9,788 8,580 7,827 6,706 5,507 4,585 3,435 2,240 Lbs. 23,273 21*445 19,682 16,535 M,778 12,602 11,468 9,772 7,9i6 6,660 4,970 3-333 In. 3 .205 150 .100 Lbs. 21,248 15,542 11,088 8,461 Lbs. In. .615 565 .510 445 .404 .358 .283 245 .183 145 .104 057 Lbs. 82,871 76,962 69,984 62,591 57,623 51,382 40,486 35,7" 27,978 22,213 i6,533 9>452 .050 045 .041 34 .032 .028 .022 3,646 3,362 2,538 2,212 1.544 5.448 4,997 3,73 3,54 2,964 2,448 * Ordnance Manual. f Seaton on Marine Engineering. Ordnance Manual. 278 MATERIALS OF ENGINEERING NON-FERROUS METALS. SHEARING. Angle formed by shear-blades, 3 degrees. Sheet Metals. IRON. COPPER. BRASS. STEEL, PUDDLED. Thickness. Pressure. Thickness. Pressure. Thickness. Pressure. Thickness. Pressure. In. I.O* .615 .510 .404 .283 .183 .104 .057 Lbs. 144,000 53,440 39,*5 25,970 i5,7!5 10,390 4,200 2.180 In. .207 .238 .204 .150 .09 .064 05 .02 Lbs. 11,196 6,007 4,820 3, 6 7 6 2,200 I, OO6 552 "3 In. 05 042 035 025 024 Lbs. 54 423 313 220 200 In. 24 24 Lbs. I4,020t 14,9301: Bolts. IRON. COPPER. BRASS. Diameter. Pressure. Diameter. Pressure. Diameter. Pressure. Diameter. Pressure. In. Lbs. In. Lbs. In. Lbs. In. Lbs. 1.142 35-4 10 .697 13,979 943 18,460 I. IIO 29,790 1.040 3,77 .585 J ,593 .906 13,872 .905 22,386 945 24,057 447 5,543 775 11,310 779 17,976 .812 19,688 .320 3W3 635 8,218 .648 11,648 The shearing resistance of copper is usually given in office hand-books as from 22,000 to 30,000 pounds per square inch (1,420 to 2,109 kilogs. per sq. cm.). Its value may be taken as the same as in tension and as subject to the same variations. The work done in shearing copper is, according to Has- well, measured, for punched holes, by W= 96,000 dt, in which W is the work in foot-pounds, d the diameter of the hole, and t the thickness of the sheet in inches. 171. Resistance to Compression varies with copper, as with all ductile and malleable metals, more with variation of form of test-piece and method of application of the stress than with the ordinary modifications of composition and of form produced in manufacture, as ingots, sheets, rods, bolts, * The cutters were parallel ; the bar 3 inches wide. f With oil. % Without oil. STRENGTH OF NON-FERROUS METALS. etc. The application of a crushing force to a test-piece of standard size and proportions first reduces it to the barrel- form, then to that of a flat cheese-shaped mass, and finally to a sheet of which the total resistance to compression increases indefinitely as its area becomes greater by flow. The com- pression stress thus increases from about that required to pro- duce rupture by tension to that demanded to produce free flow when the intensity of the stress is a maximum ; and its total amount is limited only by the area of the sheet pro- duced. The intensity, C, of resistance to compression is usually incorrectly stated, without limitation, as about 100,000 pounds per square inch (7,030 kilogs. per sq. cm.) for rolled or forged, and 120,000 pounds (8,436 kilogs.) for cast copper. The results of experiments of the Author, presently to be given, indicate that good cast copper, in cylinders of three diameters length, will exhibit a resistance which may usually te reckoned up to a compression of one-half or more, as VT C= 145,000 y ' nearly, C m = 1 0,000 1/ e ' nearly, where C and C m are the resistance to compression in British and metric measures, and e is the compression in unity of length, the resistance being reckoned per unit of original sec- tion. But the volume of the piece remaining practically un- altered, the section is increased very nearly in proportion to the compression, and the resistance will thus become f 7 - C* = 72,000 A/ ' nearly, C m = 5>oo 4/ ' nearly, when reckoned per unit of area of section actually, at the 280 MATERIALS OF ENGINEERING NON-FERROUS METALS. moment, under compression. Thus, for good cast copper, the intensity of pressure producing flow may be taken as not far from 75,000 pounds per square inch (5,270 kilogs. per sq. cm.). Cast copper under compression gives the detailed results exhibited in the next tables, as obtained by the Author for the U. S. Board. TABLE XL. TESTS BY COMPRESSIVE STRESS. CAST COPPER. No. 3 o. Material : Lake Superior copper, cast in iron mould. Dimensions : Length, 2" (5.08 cm.) ; diameter, 0.625" ( x -6 cm.). W K S6 - w K S6-- < . D ^ Q H 5 ^ O \*\ 1 |g b. Z 35 o w 1 |g |o Q s Q I 1/3 as g h Z o w a b 2 S S 2 W a; J u gz tS w J M K 3 Q g < 2 9 g Q s 5 z 3 8 3 8"" 3 8 O J 8" M Pounds. Inch. Pounds. Pounds. Inch. Pounds. 150 .0000 20,000 .6461 65,188 323 4,000 .0006 13,038 .0023 22,000 .7295 71,709 3647 6,000 .0089 19,557 .0044 24,OOO .7936 78,228 .3968 8,000 0573 26,075 .0286 26,000 .8619 84,747 439 0,000 .1560 32,595 .0780 28,000 .9258 91,266 .4679 2,000 .2568 39, TI 4 .1284 30,000 .9783 97,7 8 5 .4891 4,000 .3602 45,633 .1801 32,000 1.0308 104,303 5*54 6,000 8,000 .44 8 9 55" 52,152 58,671 .2244 .2756 Specimen did not show any cracks, but merely flattened down. STRENGTH OF NON-FERROUS METALS. 28 1 Both are tests of cast copper, and their difference illustrates well its variability in quality as ordinarily cast. With proper fluxing and protection from oxidation and absorption of air, the metal should give a uniform and maximum resistance. Rolled Copper, according to Trautwine, is compressed ^jth by a load of 103,000 pounds per square inch (7,241 kilogs. per sq. cm.). Its maximum strength in this direction is not far from that of cast copper, as above, although its resistance rises more rapidly as pressure is applied and compression produced. 172. The Compression of Rolled Copper by Impact has been determined by the Author while investigating the efficiency of " drop-presses," such as are used in making " drop-forgings." Two drop-hammers of each of two kinds were used in making the comparison, weighing with dies about nine hundred and about three hundred pounds respectively, plain. They were adjusted to fall twenty-eight inches. The lost work was from 10 to 30 per cent. The gauges used in measuring the work done by the hammers were cylinders of pure merchant copper, prepared for the purpose. They measured : Size No. i. . .... 2j^ inches long l^ inches diameter. " " 2 2 " " I " " 3 1% " " % " Of these, a considerable number were prepared and divided into three sets ; one for use with each kind of hammer, and one for testing and standardizing in the testing machine. The work done by crushing the standards in the testing machine, to the same extent that companion specimens were crushed under the hammers, gave a measure of the action of the latter, and permitted a fair comparison to be made. The amount of work done in the slowly-acting testing machine, in producing a given compression, is somewhat less than where the same effect is suddenly produced, as by a falling weight ; but this difference is not great and, if it could be 282 MATERIALS OF ENGINEERING NOX-FERRO US METALS. determined and introduced, would increase the figure here given for efficiency. The results of the experiments thus made are exhibited in the accompanying table, and are also shown in the diagram, Fig. 7. The final results are given in foot-pounds of work per pound of hammer, and the unavoidable differences in size are thus eliminated. The modulus of resistance to compression is also given. TABLE XLI. TESTS OF COPPER BY IMPACT. WORK OF THE DROP-HAMMER. WEIGHT OF DROP. 903 Ibs. 319 Ibs. SIZE OF COPPER CYLINDER. 2^"xi4"diam- i" x 2" No. I. No. 2- 1 l" X 2" |" X 1^" No. 2. No. 3. Area in square inches"! under compression ( curves. (See plate.) AD E A H I 45-23 45-26 Average, 45.34. AN O AR S 13-75 T 3-76 Average, i3-75i- Reduced to work done, ) or inch pounds. j 22,715 22,630 Average, 22,672. 6,875 6,880 Average, 6,877. Ditto in foot pounds. . . . Average, 1,884. Average, 576. Work done per pound ) of drop in inch > pounds. ) Average, 25.10 Average, 21.56 Ditto in foot pounds. ... Average, 2.09 Average, 1 . 8 Final resistance to ) compression. \ 70,000 Ibs. 31,751 kilogs. 35.000 Ibs. 15,876 kilogs. The final resistance to compression in the testing machine was very nearly 25,000 pounds per square inch (1,760 kilogs. per sq. cm.). The method of variation of resistance is well shown in the accompanying diagram, in which the compres- sion, in inches, is measured by abscissas, and the total corre- sponding load in pounds, by ordinates. The curves are nearly cubic parabolas. \ > \ \ K W c a S 8 Q ;= J * c^ I OC n fe ! z 1 2 1 S i ui s e S - s -- -' 9 ! a: z oc < < < \\ ' I 284 MATERIALS OF ENGINEERING NON-FERROUS METALS. The effect of impact on the tough metals having no definite limit of elasticity is modified by the velocity of the striking mass, and by the inertia of the piece attacked, to an extent, as yet, not fully determined. The experiments of Kick indicate a considerable increase of total work of resis- tance, when the piece is deformed in this manner, over that noted when the compression is produced slowly by steady pressure. The experiments of the Author also indicate that this work is the greater, with soft and malleable metals, as the velocity of action is increased. The real efficiency of the press, as above, is thus probably somewhat greater than the figures obtained would indicate. In the preceding figure, the areas cut off under the curves by the ordinates in full lines are measures of the work of the most efficient drop-hammers, while those cut off by the dotted ordinates give the work of less efficient machines. 173. Copper, Subjected to Transverse Stress, is prob- ably always to be considered as belonging to the second class of materials treated of in Art. 161, and as more correctly rep- resented by the equation b (p. 260) of Art. 166, than the usually adopted equations preceding them, i.e. M 1 = R ' f l y 'hi g *"**i2 o *P 1^ 8 o ^ ^ ,^ *+H be C a o 1 18 8* "5 ji bJO 3 c i 1 7 8 3 8 rt .H 1 PQ 1 w S 1 i s 1 H w & Brit. Meas. 765 26,357 0.232 10,076,756 0.0628 23,118 26,817 0.491 118.06 41.79 o-354 o . 2630 Metric 348 1,853 0.232 708,396 0.0628 1,625 15885 0.491 16.4 5-8 -354 0.263 The composition of these bars of copper was found to be ANALYSES OF TURNINGS FROM FOUR BARS OF COPPER. NO. I. NO. 30. NO. 53. NO. 57. Metallic silver O.OT? O.OI4 0.015 0.063 Metallic iron , . O O2O O OI4. O.O^ 1 ? O.OId. Metallic zinc ... O OI4 O.O^7 o 016 None. Metallic lead Trace. Trace. None. Trace. Metallic bismuth . . . None None None None. Metallic arsenic None None. None None. None. None. None. None. Suboxide of copper . 12 O86 q e8o 6 7^0 i .620 Metallic copper 87 QOO 06 ^o Q1 . 2OO 08. ^^o Insoluble matter o oo^ Carbon .. .. None 100.055 99-995 99.996 100.032 177. The Strength of Tin, as obtained in the market, is variable with the brand, the purity, the soundness, and den- sity of the metal, with the temperature and the velocity of distortion and rupture, and with other variable conditions, as STRENGTH OF NON-FERROUS METALS. 289 is the strength of copper, but in less degree so far as it de- pends upon the skill and care of the metallurgist. It is less subject to injury by the presence of deleterious elements, and is less liable to become unsound in melting and casting. Mallet obtained a tenacity of 5,600 pounds per square inch (3,936 kilogs. per sq. cm.), Rennie about 5,000 pounds per square inch (3,515 kilogs. per sq. cm.), and the Author has obtained figures for the U. S. Board, and in other experi- ments, ranging from 2,000 to 6,000 pounds per square inch (1,406 to 4,218 kilogs. per sq. cm.) for Banca and Australian tin of the following composition : COMPOSITION OF TIN OF COMMERCE. INGOT BANCA TIN. INGOT QUEENSLAND TIN. Metallic iron O.O^5 O.O 1 ^ None. None. Metallic silver . . Metallic arsenic None Trace. None. None. Metallic cobalt . ... None. Metallic bismuth None. None. Metallic nickel None Metallic lead . . None o. 165 Metallic manganese 0.006 None. None. Metallic tungsten None. Metallic copper None. None. Metallic tin . 00.078 QQ 704. Suboxide of copper Matter insoluble in ap.ua regia ... Trace 100.013 IOO.OOO In casting tin in iron moulds, a difficulty was met with in the formation of surface " cold -shuts," producing an irregu- lar section in bars of otherwise sound condition. Tests made as above give data as follows : 19 2QO MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XLIV. TENSION TESTS OF TIN (Banco). Nos. 29 A, and 29 B. W Pi VO 26 2 K Ii ll ii! Broke % inch from A end. . p o 2 %< Diameter of fractured section 0.490 inch 1 s H 3*2 (approximately). The section was very much distorted, and an exact measurement could not be obtained. Pounds. 1,700 Pounds. Inches. 0.15 .025 Tenacity per square inch of original section, considering 1,400 pounds as the breaking load, 2,800 pounds (with gradual test) (1,462 kilogs. o Set 0.15 .025 per sq. cm). Reduced to 1,250 2,500 0.19 .0318 In 2 m. 2,500 0.27 045 1,400 2,800 0.32 533 In 10 m. 2,800 1.70 2833 975 1,950 O.OI .0017 Broke 2 inches from D end. 1,180 1,290 2,360 2,580 0.03 0.09 .0050 .0150 Fractured section very irregular, and drawn out almost to a point. Estimated diameter of i, 600 2,000 3,200 4,000 O.2O 0.58 .0332 .0963 final section 0.300 inch. Tenacity per square inch of original section 2,IOO 4,2OO Piece extending rapid 1.88 ly and strain , -3^3 reduced to (with rapid test) 4,200 pounds (2,953 kilogs. per sq. cm.). 1,700 3,400 2.58 .4269 TABLE XLV. Summary.. DIAMETER. il TENACITY PER SQUARE J, u .2.5) llg NO ll ll *^r /*. 9 Queensland tin.. Banca tin 22 22 1.038 0-993 1.023 1.002 150 no 4.559 3.740 t: 4 3 .=67 .273 i'Js'J'i Bent. Bent. Mean of 2 bars.. 130 4.150 .270 6,185,210 294 MATERIALS OF ENGINEERING NON-FERROUS METALS Queensland tin proved very good, showing a somewhat greater strength by transverse and torsional test than Banca tin, but a less strength by tension. The transverse strength probably appears higher than it should be, both on account of different methods of test, the Banca tin being tested by dead loads and the Queensland tin by platform-scale, and on account of a perceptible flaw in the centre of the Banca bar. In the test of No. 29, as above, a load of 40 pounds pro- duced a set of 0.0095 inch, and the elastic limit appeared to be reached at about 30 pounds. At 80 pounds a crack was observed on one of the edges on the under side of the bar, which gradually opened but did not increase in length. At 1 10 pounds the bar sank gradually, the -deflection increasing more than 6 inches in ten minutes. The bar was finally broken by repeated bending, and showed that the crack above mentioned was produced by an imperfection in the casting, about one-fourth of the surface, or that portion in which the crack was observed, showing radiated lines of cooling and the remainder the close pasty appearance peculiar to tin rupt- ured by bending. The crack weakened the bar, and the final bending was resisted by but little more than three-fourths of the section. Major Wade found the tenacity of Banca tin used in mak- ing U. S. Army ordnance to be 2,122 pounds per square inch (148 kilogs. per sq. cm.) ; its density was 7,297. 179. The Modulus of Elasticity of Tin is stated by Tredgold at 4,600,000 pounds per square inch (285,400 kilogs. per sq. cm.) for cast metal, by Molesworth at same figure nearly, and is found by the Author to vary up to nearly 7,000,000 pounds (492,000 kilogs., nearly). Some of the figures obtained are given in the records of transverse tests of cast tin already referred to. No values have been found for other forms of this metal. Tin is, however, probably less affected by the form in which it enters the market than other common metals, and the moduli here given may be accepted for general use as sub- stantially accurate. 180. Tin in Torsion, as tested by the Author, gives STRENGTH OF NON-FERROUS METALS. 295 figures of which the following, from the Report of the U. S. Board, may be taken- as fairly representative : TABLE XLVIII. TORSIONAL TESTS OF TIN. Averages of Results calculated from Autographic Strain-Diagram. ORDINATES TORSIONAL MO- k OF DIAGRAM. MENT. s bp g i S 1 *i ^ MATERIAL. i 8 B 1 J5 ^ a g g 3 . .2 \ *o 8 3 g I c g & bo K "o X V M 1 9 < 3 * O K 58 Queensland tin .. Banca tin Sq. ins. 42.78 21.20 Degrees. 691.0 556.8 Ins. 0.22 Ft.-lbs. Ft.-lbs. 4.36 5.78 2.9029 2.1975 Ft.-lbs. 208.48 105.45 3 4 Mean (British) ... Metric .... O.l8 0.46 32.02 20.6 623.9 623.9 0.61 1.6 # 5-07 0.7 2.5502 156.97 The Queensland tin showed an extraordinary ductility in the torsional tests, one of the pieces twisting through an angle of 818 degrees, or more than 2^ turns before breaking. This represents an elongation of a line of particles parallel to the axis on the surface of the cylindrical portion of the test-piece from one inch to 4.57 inches. The average of all tests of tin is given in the following : AVERAGE RESULTS OF TESTS OF TIN. TRANSVERSE TESTS. TENSILE TESTS. TORSIONAL TESTS. I 3 c a'" 4^50 I .270 s CO I 6,185,210 part length. 355' Tenacity per square inch of .476 392 2.5502 156.97 296 MATERIALS OF ENGINEERING NON-FERROUS METALS. 181. The Strength of Zinc has been determined by but few investigators, and, like that of all other useful metals except iron and steel, is a subject of which comparatively little is known by the engineer. Cast zinc is stated to have a tenacity of about 4,000 pounds per square inch (281.2 kilogs. per sq. cm.), and a resistance in compression of ten times that amount. Stoney states the tenacity at nearly 3,000 pounds (211 kilogs.) cast, and Traut- wine gives for sheet-zinc and zinc wire 16,000 and 22,000 pounds per square inch (1,124.8 and 1,546.6 kilogs. per sq. cm.), respectively. The modulus of elasticity is given by Wer- theim and by Tredgold at from 12,000,000 to nearly 14,000,000 pounds per square inch (843,600 to 984,200 kilogs. per sq. cm.), the value being higher for cast zinc. The Author has obtained much smaller figures. Pure zinc, like pure tin, is never used alone, by the engi- neer, for purposes demanding strength and toughness. The values of the several moduli are given as of interest, how- ever, and for comparison. Samples of cast zinc tested by the Author show variable tenacity, the figures ranging between 4,500 and 6,500 pounds per square inch (2,847 to 4 2 53 kilogs. per sq. cm.), or consid- erably above those given by earlier investigators. All the zinc thus tested by the Author was very pure, and made from New Jersey calamine. The effects of varying time and rapid- ity of strain are observable in zinc, as in tin, and are the same in kind ; they will be described later. Zinc is much less ductile than tin. The resistance of zinc to compression varies with the de- gree of reduction, and, as tested by the Author, was about 22,000 pounds per square inch (1,547 kilogs. per sq. cm.) when the compression amounted to one-tenth the original height of test-piece in pieces three diameters long, and one-half greater for a compression of one-third. Zinc is weaker under compression than any copper-zinc alloy. Zinc has no defined elastic limit, but an apparent elastic limit in compression was recorded at 5,000 pounds per square inch (352 kilogs. per sq. cm.). STRENGTH OF NON-FERROUS METALS. 297 182. Records of Test of Zinc are given below, as reported to the U. S. Board. TABLE XLIX. TENACITY OF CAST ZINC. Length, 5"; diameter, 0.798". LOAD. TOTAL EXTENSION. SET. PER CENT. ELONGATION. REMARKS. 800 O OOI I O O2 I 2OO 0.0024. O O2 1, 600 o,. 0014 O O7 Section o 706'' 2,OOO 0.0051 O IO Tenacity 6 300 pounds 3,OOO 0.0097 O. IQ per square inch (4 420 4,OOO 0.0157 O 11 kilogs per so cm ) 2OO o 0006 5.OOO 0.0206 o 41 6,OOO o 0240 o 48 6.3OO Broke. COMPRESSION OF CAST ZINC. Length, 2" ; diameter, 0.625' COMPRES- COMPRES- LOAD. SION. LOAD. SION. Total. Per sq. in. Per cent. Total. Per sq. in. Per cent. 1,000 3,259 0.15 8,000 26,076 12.15 2,000 6,519 0-55 9,000 29,335 17-15 3,000 9,778 1.85 10,000 32,595 20.60 4,000 13,038 3-40 10,000 a 21.80 5,000 16,297 5.10 10,500* 34,225 24.40 6,000 19*557 7.20 Resistance fell to 7,000 22,816 10.65 10,000 32,595 33-35 * Continued one minute. 298 MATERIALS OF ENGINEERING NON-FERROUS METALS. CAST ZINC LOADED TRANSVERSELY. LOAD. DEF. SET. E. REMARKS, 2O O OIOI 40 60 80 100 120 140 a 0.0171 0.0246 0.0324 0.0424 0.0506 0.0616 O O 6,698,725 6,927,556 6,984,644 6,655,180 6,680,965 6,395,032 Modulus of rupture, R 7, 540 pounds per sq. in. (5,300 kilogs. per sq. cm.). Most probable value of E 6,900 ooo 1 60 1 80 2OO Broke 0-0753 0.0906 0.1244 5,973-588 5,581,549 1,797,132 E m 428,130. TESTS OF CAST ZINC BY TORSION. Length, i" ; diameter, 0.625". NO. AREA DIA- GRAM. ANGLE. MAX. ORDI- NATE. MAX. MO- MENT. EXTEX. EXTER. FIBRE. 21 A 19.63 123 2.15 37-83 o . 2042 21 C 18.81 I2 9 2.07 36.55 0.2227 21 D 17.24 151 1-95 34-42 0.2955 21 B 18.13 I6 3 2.15 37.83 0.3380 183. Other Metals than those already described have been made the subject of very few experiments and the data obtainable are very unsatisfactory. The alloys of the three principal non-ferrous metals are made the subject of succeed- ing chapters. Lead has a tenacity which is reported by Haswell as : LBS. PER SQ. IN. KILOGS. PER SQ. CM. Lead, cast I 8OO 116 " milled . 233.4 wire 258O 181.4 In compression the resistance is stated to be 7,700 pounds STRENGTH OF NON-FERROUS METALS. 299 per square inch (541 kilogs. per sq. cm.) and the modulus of elasticity is given as 720,000 Ibs. (49,350 kilogs.). Wertheim, however, obtains a value of 21,500,000 pounds per square inch (175,750 kilogs. per sq. cm.). Trautwine gives, for tenacity : LBS. PER SQ. IN. KILOGS. PER. SQ. CM. Lead cast I 800 to 2,400 116 5 to 168 7 nine I 7OO to 2 24O no z to 1^7 % wire 1, 6OO 1 12 H sheet I Q2< re c c "ODO as collated from various older experiments, and a resistance to compression, agreeing with Haswell. The strength of lead pipe, as obtained in market, has, when tested, been found variable. The best results noted by the Author * indicate a tenacity of the metal exceeding one ton per square inch (2,240 Ibs.; 157.5 kilogs. per sq. cm.). Comparing the results of a number of experiments to obtain a value of/ in Clark's formula: /= ThgR\ logR 1 in which T is the tenacity, / the pressure, and R the ratio of external and internal radii, a mean value of T was found to be 1.4 tons per square inch (220.5 kilogs. per square cm.). The minimum value was three-fourths as great. It is prob- able that a much lower pressure, long continued, would have burst these pipes. The thickness of lead pipe is frequently determined by the rule : / = 0.0024 n d + 0.2, in which t is the thickness in inches, n the pressure in atmos- pheres and d the internal diameter in inches. Lond. Engineer ; Nov. 16, 1883, p. 378. 300 MATERIALS OF ENGINEERING NON-FERROUS METALS. Antimony has a tenacity of about 1,000 pounds per square inch (70 kilogs. per sq. cm.), and bismuth of three times that amount. Gold is a moderately strong metal, with a tenacity, cast, of 20,000 pounds per square inch, and of 30,000 in wire (1,406 to 2,109 kilogs. per sq. cm.). Silver is reported to be about equally strong (?) in the two forms, having a tenacity of 40,000 pounds per square inch (2,812 kilogs. per sq. cm.), according to Baudrimont. Platinum has a strength of from 30,000 to above 50,000 pounds (2,109 to 3>5 ! 5 kilogs.). Nickel, tested by the Author, exhibited tenacities of from 50,000 to 54,000 pounds per square inch (3,515 to 3,543 kilogs. per sq. cm.), elongating about 10 per cent. Palladium, tested by Wertheim, had a tenacity equal to that of nickel. It is ques- tionable whether any of these metals have a true elastic limit. 184. Wertheim on Elasticity. Wertheim gives the fol- lowing as the densities, atomic weights, and products of the two, and also the tenacities and sound-conductivity of several metals : S. G. AT. WT. < X o* en RESISTANCE TO RUPTURE PER MILLIMETRE. Coefficient of elasticity (Tredgold). 13 e 3 o cfl "1 3 >,.u Tj 'a, rt & Ji5 gS QJ 4_> "5 ^^^ o 3 rt >P > PQ"" S If 8|^ X ^ ^ pp Lead H-352 7.285 19-258 10.542 6.861 21.530 8 850 7.788 12.94498 7-35294 12.43013 6.75803 4.03226 12-33499 3-95695 3 39205 0.8769 0.9907 1-5493 J-5599 1.7015 1-7454 2.2365 2.2959 O.O22 0.063 0.274 0.341 0.199 0.499 0-550 1. 000 i-45 6. 20 600 3.200 7-5 Tin Gold Silver 38.55 9.600 20.000 9.0 12.0 17.0 Zinc Platinum Copper . . Iron He infers a general variation of cohesion with change of intramolecular distances, and obtains his data from experi- ments upon fifty-four binary alloys and nine ternary alloys, among which are found also most of the alloys employed in S TRENG TH OF NON-FERRO US ME TALS, 30 1 the arts, such as brass, pinchbeck, gong-metal annealed and unannealed, bronze, packfong, type-metal, etc. These experiments gave the following results : 1st. If we suppose all the molecules of an alloy to be the same distance from one another, we find that, in general, the smaller the mean distance, the greater is the coefficient of elasticity. 2d. The coefficient of elasticity of the alloys agrees suf- ficiently well with the mean of the coefficient of elasticity of the constituent metals, some alloys of zinc and copper being the only exceptions. The only condensations and expan- sions which occur during the formation of the alloy do not sensibly affect the coefficient. We can then calculate before- hand what should be the composition of an alloy in order that it may have a given elasticity, or that it may conduct sound with a given rapidity, provided that this elasticity or this velocity fall within the limits of the values of these same quantities for the known metals. 3d. Neither the tenacity, nor the limit of elasticity, nor the maximum elongation of an alloy can be determined a priori by means of the same quantities as determined for the metals which compose them. 4th. The alloys behave like the simple metals as to longi- tudinal and transverse vibrations, as well as elongation. Wertheim,* experimentally determining the moduli of elasticity of various metals, under varying conditions, came to the following conclusions : 1st. The modulus of elasticity is not constant for the same metal ; whatever augments the density increases it, and re- ciprocally. 2d. The longitudinal and transverse vibrations give the same modulus of elasticity. 3d. Vibration gives moduli of elasticity much greater than those obtained by elongation. This difference is due to the acceleration of movement produced by liberated heat. 4th. Consequently, sound in solid bodies is due to waves and condensation, and we may be able by means of the for- * Comptes Rendus, Vol. 15, 1842. 3O2 MATERIALS OF ENGINEERING NON-FERROUS METALS. mula of M. Duhamel to find the relation of specific heat under constant pressure to that at constant volume. This ratio is greater for annealed than for non-annealed metals. 5th. The modulus of elasticity diminishes with the eleva- tion of the temperature at a more rapid rate than that which is due to the corresponding dilation. 6th. Magnetization does not sensibly change the elasticity of iron. /th. The elongation of rods and bars by the application of loads affects their densities very slightly. The coefficient of elasticity should, therefore, vary as little in the different po- sitions of equilibrium ; and this is, in fact, what takes place, in so far as the loads do not become great enough to produce rupture. The law of Gerstner is therefore confirmed by all the metals of which the particles take a position of equilibrium after having passed their limit of elasticity. 8th. The permanent alloys are not found intermittently, but in a continuous manner. By suitably limiting the load and its duration of action, such permanent elongation as may be desired can be produced. Qth. No true limit of elasticity exists ; and if no perma- nent elongation is observed for the first loads, it must be be- cause they have not been allowed time to act, and because the rod submitted to the experiment is too short relatively to the delicacy of the measuring instrument. The values of maximum elongation and of cohesion also depend much on the manner of operation. They become greater the more slowly the loads are increased. It may be seen from this how arbitrary is the determination of least and of greatest permanent elongation, and that we cannot found a law upon their values. loth. The resistance to rupture is considerably dimin- ished by annealing. The elevation of the temperature, even to 200 C., does not greatly diminish the cohesion of metals previously annealed. Wertheim's values of the moduli for several metals are, in round numbers, as follow.* * "Physique Mecanique." STRENGTH OF NON-FERROUS METALS. TABLE L. MODULI OF ELASTICITY OF METALS. 303 LBS. PER SQ. IN. KILOGS. PER SQ. CM. Lead 2,500 ooo 176 ooo 7,700,000 492,000 Gold II 500,000 808 500 Silver . 10,000 ooo 70^ ooo 17,000,000 1,195,000 Platinum . 24 ooo ooo i 687 ooo Bischof s Method of Test to determine the purity and economic value of metals consists in making strips of a definite and standard size and subjecting them to repeated bending. The purer the metal, as a rule, the greater the number of changes of form required to produce fracture. Zinc, for example, was found to withstand 100, 54 or 19 bendings accordingly as it was pure zinc, best commercial spelter or the lowest quality. The ill effect of the introduc- tion of o.ooooi tin, or of 0.0004 cadmium is perceivable even more certainly than by analysis. Metals which do not alter by remelting, as tin or zinc, are melted in crucibles, with continual stirring and then cast in ingot moulds, 12 cm. long, 1.3 cm. square at the top and 0.3 cm. square at the bottom, 40 or 50 grammes being taken for a test, or 60 grammes for lead. The bars thus made are rolled to the desired thinness, annealed and tested. Metals, as brass, bronze or copper, which are liable to change in fusion, are rolled from the commercial form, with repeated annealing. The strips tested by Bischof were 13 cm. (4 inches) long, 0.7 cm. (2 inches) wide and of such thickness that they weigh as follows: Copper, 17; brass, 16; tin and zinc, 15; lead, 25 ; iron and steel, 12 grammes. They were tested in a " metallometer," in which they could be bent conveniently to any angle. Repeated flexure and reflexure through an angle of 67^ degrees was found best adapted to bring out the quality of the metal. Ten strips were tested simultaneously, 304 MATERIALS OF ENGINEERING NON-FERROUS METALS. and fifty tests were usually made of each metal, occupying from an hour to an hour and a half. The following are some of the results : (l.) ZINC. NUMBER OF BENDINGS OF CHEMICALLY PURE ZINC IOO. IOO parts chemically Hi' . pure zinc alloyed ta ^ c o with 'a -6 s a U HJ uS M 3 5 . o parts .... JS 80 4.0 76 C ^ 3.0 S-d T3 93 73 V . . 2.0 C jy C jy 77 3 2 . . 1.0 13 *2 2 2 95 61 (j ^ 0.5 ";3 3 54 52 0.25 .... u u IOO 61 59 95 0.10 53 29 64 64 89 0.05 57 35 . . 69 62 97 0.025 57 . . 83 60 0.0125 .... 45 . . 82 70 0.00625 63 . . 85 75 .. 0.003125 .... 58 92 90 0.0015625 .... 69 94 88 0.00078125 90 9 1 93 0.00039062 85 85 0.00019531 .... 84 0.00004382 89 . . 0.00001095 ' .... 93 The numbers of bendings of about 25 different kinds of zinc from the market were found to lie between 54 and 19. (2.) TIN. NUMBER OF BENDINGS OF BANCA TIN TOO. IOO PARTS OF BANCA TIN ALLOYED WITH LEAD. ANTIMONY. 2.5 " 2O J u Afi I.O " Z V fi/l o.r " J5 4 0.05 " / 84 The numbers of bendings of 4 kinds of Banca tin, obtained through different sources, were respectively 100, 101, 88, and 78. STRENGTH OF NON-FERRO (3.) LEAD. NUMBER OF BENDINGS OF M M M MECHERNICH EXTRA IOO. IOO PARTS OF M M M ALLOYED WITH TIN. ANTIMONY. c.O parts. . e I 2.5 ' CA \ i.o " 84 71 0.5 " , 87 74. O.I " Ql IOO The numbers of bendings of 4 different brands of lead from the market were found between 100 and 89. 185. Aluminium, according to Mr. A. E. Hunt,* gives the following : FORM. RED. OF AREA. POUNDS PER SQUARE INCH. Elastic Limit. Tenacity. Modulus Elasticity. Cast 0.10 .25 .40 .20 5,000 12,000 16,000 to 30,000 10,000 15,000 24,000 30,000 to 65,000 28,000 11,000,000 15,000,000 15,000,000 15,000,000 Thin sheet Bars In compression the elastic limit is found at about 3,500, the ultimate resistance at 12,000. The modulus of resilience is 0.16 to 0.22. In shearing it ranges from 12,000 to 16,000, about equal to pure copper. Specific gravity varies between 2.55 and 2.65. Further, are given the following: MATERIAL. WEIGHT PER CU. FT. TENACITY, LBS. PER SQ. IN. LENGTH OF BAR, SUSTAINING ITSELF. 444 l6,OOO 535 ft K25 3I,OOO Q.8Q3 \Vrought iron* .. 480 5O,OOO 15,000 Al. sheet 165 26,OOO 23,000 168 55,OOO 30,615 cast 160 15 ooo 1^,^21 forged 165 20,000 17,700 Its conductivity is high, it is non-magnetic, sonorous, and exceedingly malleable. It has many valuable alloys, and is much used in iron and steel castings to confer soundness. * Jour. Franklin lost., Feb., 1891 ; May, 1892. 20 CHAPTER IX. STRENGTH OF BRONZES AND OTHER COPPER-TIN ALLOYS. 186. The Bronzes under which name are included the principal alloys of copper and tin, and a few special composi- tions vary, in strength, elasticity, ductility and hardness, with variations of composition to such an extent that they find application in an immense number of the engineer's construc- tions, their character and chemical constitution being adjusted to his needs. The most common of these alloys is " gun- bronze," which consists, usually, of 90 parts copper, 10 of tin, or 89 copper, 1 1 tin. Such bronze has a strength which will depend greatly on the soundness of the castings and purity of the constituents of the alloy, but which often may exceed 50,000 pounds per square inch (3,515 kilogs. per sq. cm.) in tension. Bronze used for journal-bearings in machinery is made harder or softer, according to pressure sustained, the com- position approaching usually that of gun-bronze, and ranging from copper, 7; tin, i; to copper, 11, tin, i; i.e., copper, 87.5; tin, 12.5, to copper, 91.67; tin, 8.33. A little zinc or lead added slightly softens it. Packing rings for steam engines are made of still softer and more ductile bronze copper, 92, to copper, 96. These alloys have been very fully described elsewhere, and this chapter is devoted entirely to the consideration of their strength, ductility, elasticity and density. 187. Gun-bronze, according to the " Ordnance Manual," should have a tenacity of 42,000 pounds per square inch (2,826 kilogs. per sq. cm.), and a specific gravity of 8.7. In Major Wade's report on " Experiments on Metals for Cannon," 1856, are given records of a number of tests of gun metal. Specimens of metal from 83 " gun-heads" (the upper part STRENGTH OF BRONZES. 3O/ of the casting is always deficient in strength) gave an average result of 29,655 pounds per square inch (2,085 kilogs. per sq. cm.), the highest figure being 35,484 and the lowest 23,529 pounds. This alloy was copper, 9; tin, I. Small bars made of gun metal gave higher figures. One set of 16 bars gave an average result of 42,754 pounds (3,006 kilogs. per sq. cm.), and another similar set an average of 41,284 pounds (2,902 kilogs. per sq. cm.), the lowest figure of the 32 specimens being 23,854 pounds and the highest 54,544 pounds. Five of the specimens gave more than 50,000 pounds (3,515 kilcgs. per sq. cm.), and only three less than 30,000 pounds (2,109 kilogs. per sq. cm.). The average of 12 gun-heads was one-half that obtained from the small sample bars cast with the guns. A sample of very inferior quality fell below 18,000 pounds (1,265 kilogs. per sq. cm.). Major Wade found the quality of bronze ordnance enor- mously irregular and uncertain, and considered it very im- portant that a more reliable method of manufacture should be found. The tenacity of gun-bronze thus depends greatly upon the method of manufacture, of casting, and of cooling. By careful handling it has been given a tenacity, in ordnance, exceeding, even, 60,000 pounds per square inch (4,218 kilogs. per sq. cm.), and the Author has obtained small bars still stronger. Bronze ordnance of large size has been made here and in Europe with success ; it is, however, very liable to be irregular in composition and physical character, and the un- certainty always felt in regard to its condition is an element which enters into the question of its use for any purpose. Continual use of ordnance is thought to lead to a separation of the tin from the copper, and to final destruction. The gases of powder sometimes corrode the metal badly. The Modulus of Elasticity of gun-bronze is given by Tred- gold at 10,000,000 pounds per square inch (703,000 kilogs. per sq. cm.), and this figure is confirmed by the experiments of the Author as given later, but it is subject to great variations with the condition of the metal. 308 MATERIALS OF ENGINEERING NON-FERROUS METALS, Gun-bronze has less elastic resilience, and therefore less capacity for taking up shock without permanent deformation, than has good wrought iron, but more than gun-iron ; it wears more seriously than iron, and the finished gun is considerably more expensive, nowithstanding the comparative ease with which bronze can be worked. It is, therefore, not used very extensively for ordnance, and is less generally used than for- merly, when steel was less easily obtained for this purpose and was more costly than at present. The use of bronze ordnance will probably, in time, cease entirely. 188. Anderson's Experiments on copper-tin alloys, ap- proximating to the composition of gun-bronze, give the fol- lowing results, the tenacity being given to the nearest round numbers : TABLE LI. TENACITY OF ORDNANCE BRONZES. TENACITY, T. LBS. PER SQ. IN. KILOGS. PER SQ. CM. Copper 92 ' tin 8 29,OOO 31,000 33,OOO 38,OOO 2,039 2,116 2,130 2,l65 " QI.7 ' " 8 ^ . " OI * " Q " GO' " 10 189. Bell-Metals. Mallet, testing harder alloys, approach- ing bell-metal in character, obtained as results the tenacities given below: TABLE LII. TENACITY OF BELL-METAL. TENACITY, T. LBS. PER SQ. IN. KILOGS. PER SQ. CM. Copper, 84.29 tin 15 71 30 ooo 2 cqo " 82 81 " 17 IQ 0/1 OOO " 81 10 " 18 90 40 ooo 2 8l2 78.9^ " 21 .03 31 ooo 2 Il6 STRENGTH OF BRONZES. 309 190. Gun-bronze in Compression was tested by the Author with the following results : TEST OF GUN-BRONZE. No. 1252. Copper, 90; tin, 10 ; length, 2"; diameter, 0.769". Fluxed with mercury sulphate ; sound. LOAD J LBS. COMPRESSION, INCH. LOAD J LBS. COMPRESSION, INCH. 30,000 0.6460 36,000 0.7914 32,000 0.6904 38,000 O.8II5 34,000 0.7311 Resistance, max. 123,860 Ibs. per sq. inch, original area. 8,707 kilogs. " cm. " " Compression, in per cent., 40.57. No. 1252-2 ; as above. LOAD ; LBS. COMPRESSION, INCHES. LOAD ; LBS. COMPRESSION, INCHES. lO.OOO 15,000 20 ooo O.OOO9 0.2IIO O.35QQ 25,000 28,000 23, 5OO 0.5092 0.8o62 Max. resistance, 92,894 Ibs. per sq. inch. 6, 530 kilogs. " cm. Compression, 40 per cent. Gun-bronze under compression behaves as exhibited in the accompanying table.* The resistance at 10 per cent, com- pression averages about 40,000 pounds per square inch (2,812 kilogs. per sq. cm.) ; at 50 per cent, about 140,000 pounds (9,842 kilogs.). * Construction of Artillery, Mallei. 3IO MATERIALS OF ENGINEERING NON-FERROUS METALS. 8 ^ ^ S g <3 M s I to O * > O (NO M -NO VO 3 co * * : i : : ; "***. * :-- - 1 :: i ill i ^& 10 TT 10 >0 co JB & S : : : : : : : &* X :58N R 1 ^ ! H 5-2 : H- : : : : 8^8 : 5-\o -o ... -^- 10 . -OO CO ON N 10 co N 0 ON O O VO W lO CO . M o M 1 |>g8 o :R| | l^ ro O oo ON CO M N (M CM M 3 j % woo t^ ONQO "TN WOON CJI^-^- -rf- H O M > lOtvlO O co N w ON VO MOO N CM N N S 2 " M Tt- HOOO VD 2 H 2 CO O CM N H O f^ 10 ON t^ a a % -< ^- co vo O*oio N IO CO CO O t^CO OO CO -^t- CO M M M M MOO O f-MM fc SZZ ff s M ' 10 r^vo vo co c* co N vo t^'S fc? cT'S) co OOO O . 8, M N " o M m 10 co 10 co CMCON MOH O OHM OOO N OOO O OOO 8 888 8 ll Ej ON irl e? ON H 5-\o 1 !>. M ^ M ONOO ON COVON 1O MlOON 00*0000 00 00 00 00 CO t". t>.OO 8 s S N^^T ^ OO OO 00 OO OO w : : : : i : : : : : 1 1 J 1 1 d 4 d rt . f s s STRENGTH OF BRONZES. These experiments were made by Col. Wilmot, R.A., at Woolwich Arsenal, at the request of Mallet, in 1856. Nos. i, 2, and 3 were from the " runner " cast with a " 24-pounder " howitzer. No. 4 was from the cascabel of a similar piece of ordnance. The test pieces were two diameters long, 0.5 inch by I inch (1.27 by 2.54 cm.). 191. Hardness of Bronzes. Riche tested the hardness of copper and bronze with an apparatus producing an in- dentation by the blow of a drop or hammer falling upon a steel punch. The hardness of bronze increases very rapidly with the proportion of tin, and the following is the average of many experiments with the apparatus above referred to : Impacts necessary in order to ob- tain a depres- sion of 4 mm . I. 19 23 27 38 40 Fid no wilh 70 b 7 8 tog 10 14 15 : succeed lows. Bronze of 97 Bronze of 96 Bronze of 95 Bronze of 94 Bronze of 90 parts copper parts copper parts copper After these experiments, medals were struck at the mint in Paris. The differences, which are unimportant for medals less than 35 millimeters, become more noticeable when the dimensions attain to 50 millimeters diameter. There are necessary in this latter case With pure copper 7 compressions. With bronze of 97 parts copper, 10 compressions. With bronze of 96.5 parts copper 12 compressions. With bronze of 96 parts copper 13 to 14 compressions. With bronze of 95 parts copper 16 to 17 compressions. Alloy of 95 copper, 4 tin, I zinc 14 compressions. Alloy of 94 copper, 4 tin, 2 zinc 16 to 18 compressions. 312 MATERIALS OF ENGINEERING NON-FERROUS METALS. From which he concludes that bronze of 96 and 97 per cent, copper may be employed to great advantage and with no serious inconvenience in the manufacture of medals. Its hardness does not much exceed that of copper; it possesses sonority and casts well, rolls evenly, and its color is more artistic than that of copper. The action of the press and of heat modifies its density but little. The hardness and brittleness of speculum and bell-metals are such as to forbid the use of this method of testing them. 192. " Phosphor Bronze " exhibits much greater strength and ductility than the same metal cast without phosphorus. The following tables exhibit the data obtained by various experimenters and by several methods of test, as collated by Dick.* They show great strength and remarkable toughness. TABLE LIV. TENACITY OF PHOSPHOR-BRONZE {Kirkdldy). ULTIMATE PULLING STRESS NUMBER OF TURNS PER SQUARE INCH. IN PER CT. IN 5 INCHES. Hard. Annealed. Annealed. Hard. Annealed. Copper 63 122 Ibs 37,002 Ibs. Mi 86 7 06 Brass 81 156 CTCCJO 36.1; 14. 7 1:7 Charcoal iron 65,834 46,160 28 48 87 Coke iron. 64 321 6l 204 17 26 A A Steel 1 20 076 74,6^7 IO.Q j- 70 Phosphor-bronze No. I . 159.515 58,853 46.6 13-3 66 do do No. 2. I5I,H9 64,569 42.8 15-8 60 do do No. 3. 139^41 54,iit 44.9 17-3 53 do do No. 4. 120,950 53,38i 42.4 13 124 Elastic stress per square inch. Ultimate stress per square inch. Ultimate permanent extension in per cent. Phosphor-bronze No. I . . . do do No. 2. . . do do No. 3. . . Ibs. 55,200 40,500 26,300 Ibs. 73,987 63,653 54,o6o per cent. 3-2 94 31-3 * Journal Franklin Institute, 1879. f Of the 8 pieces of Steel tested, 3 stood from 40 to 45 turns and 5 " " il " 4 " STRENGTH OF BRONZES. TENACITY OF PHOSPHOR-BRONZE (Uchatius). 313 Specimens. Absolute resistance in kilogs. per square centimetre. Elastic resistance in kilogs. per square centimetre. Stretch in per cent. Phosphor-bronze No. o. do do No. oo. Krupp Cast Steel kilogs. 3,600 5,66o 5,000 kilogs. 600 3.800 I OOO per ct. 20.66 i. 60 II OO TENACITY OF PHOSPHOR-BRONZE ( Wofller}. Tests by Repeated Application of Direct Strain. PHOSPHOR-BRONZE. ORDINARY GUN METAL. Tensile stress Number of efforts Tensile stress Number of efforts per square in. until rupture. No. per square in. until rupture. I 10 Tons. 408,350 i 10 Tons. j Broke before total ") stress was applied. 2 12* " 147,850 2 10 " 4,200 3 7i *' 3,100,000 3 7* " 6,300 Tests by Repeated Bending in the same Direction. PHOSPHOR-BRONZE. ORDINARY GUN METAL. No. Tensile stress per square in. Number of bends until rupture. No. Tensile stress per square in. Number of bends until rupture. i 10 Tons. 862,980 i 10 Tons. 102,650 2 3 7 I ;; 4 Million ) .,_, e 2 3 7? " 150,000 837,760 4 6 " 2 " ) | A bar of hammered phosphor-bronze, under 12 tons per square inch, without breaking, stood more than 2y 2 million turns, whilst according to Wohler's experiments, a bar of Krupp cast steel under 12 tons, broke after 879,70x5 turns, and another bar of the same under 13 tons, broke after 1,007,550 turns. MATERIALS OF ENGINEERING NON-FERROUS METALS. 193. The Resistance to Abrasion of the Phosphor- Bronzes has been found such that Dr. Kunzel has adopted them, with the addition of a little lead, for the " brasses " of railway axles. The liquation occurring often results in the production of two alloys, intermingled, the one a hard, tough, strong metal which acts as a sponge, retaining the softer alloy very uniformly diffused throughout its mass. Kunzel considers that a good axle-bearing should not be homo- geneous, but must consist of a tough metal skeleton, the hardness of which should nearly equal that of the axle, and which should resist any pressure or shock without changing its form ; the pores of this skeleton should be filled with soft alloy. The nearer the hardness of the skeleton bearing approaches the hardness of the axle, the better this skeleton will resist pressure ; and the softer the metal which fills the pores, the more excellent is the bearing. Such a bearing is obtained by using a compound of two or more metals of dif- ferent tempers and melting points, and in such proportions that necessarily by cooling a separation of the metals into two parts or two different alloys of definite composition results. Bearings of phosphor-bronze alloyed with lead con- sist of a tough and homogeneous skeleton, the hardness of which may be regulated to nearly equal the hardness of the axle, whilst its pores are filled with a very soft alloy ; the wearing part of such bearings may, therefore, be considered as consisting of a great number of small bearings of soft metal, each of which is surrounded by metal of nearly the same temper as the axle ; Kunzel's particles of soft alloy may be easily discerned. When this alloy is heated to a dull red, the soft alloy exudes, whilst a hard sponge-like mass forming the skeleton of the bearing remains. Herein consists the advantage of bearings of these alloys, the axle running partly on a very soft metal, whereby heating is obviated, whilst the harder part of the bearing its skeleton checks the wear of the softer metal. The following table * shows the result of a series of experiments on such bearings. * Poly tech. Centralblatt, Jan., 1874. STRENGTH OF BRONZES. 315 J . I III 1 |So r i M i-Markisc | i -d 3 a> 1 1 i 5 U : 1 1 1 i; similar wo y. g CO ,4> P 2 o 5 S5 < o|i||| g , 1 4 s M CO CO M CO W O CO i 8 u||ii| I 6 ci 6 6 o 1 fc4v. . l<= b >= ^ 13 "" jj 9 jf 8 S^ HB ip J ^ ra c^ = l- g|t| 1-1 o" f TJ- M H 5 CS & v2 ^ M ~ * f .2 1 1 S M 1 ID Tf 1 O O f II J * * *R co" CO oo c>i o T Hi -5 3 Q 51 i Is ? 1 CO M 2 o DO CO CO N CO Q o 6 M CO M " M" 2 in nt oouad 1 joZ je uajpn fejara jo ssoi puB sasuadxa Sui -liatn am 'sajjaraoi;^ ooi aad sJSuijeaq jo jso;) * 1 1 1 CO n CO* M O O \rt u-> co co f V .2 CO CO : .2 1 c 2 _ M IH o^ >> CO >% >^ 8 ill if c 1 1 I 1 &* ex J - - .5 c^.S T3 - *N 0* c rt si j i "^ u CO M C4 \rt O ^o <2 CO CO CO CO M *^J (3 ^r ^r ~r 1 ^ . | JH rt 1 c o r c 1 1 | ? o S S f. "o 1 3 1 1 1 ~o 4^ 1 1 ^ B : 8 11 1 c o IS 1 1 J 316 MATERIALS OF ENGINEERING NON-FERROUS METALS. 194. Manganese Bronze is another valuable alloy. That used in the construction of torpedo boats for the British navy was supplied under a contract calling for a tenacity of 26 to 31 tons per square inch (4,094 to 4,882 kilogs per sq. cm.), and an elongation of 20 per cent. This sheet bronze was from T ^th to Jth inch (0.16 to 0.32 cm.) thick (No. 9 to No. 18 B. W. G.), and sustained 29 to 30 tons (4,567 to 4,725 kilogs.), stretching 25 to 35 per cent., and bending cold to a radius equal to their thickness. Manganese bronze, tested at the Royal (British) Gun Fac- tory at Woolwich, England, by tension, gave the following figures, as reported to the Admiralty : TABLE LVI. TENACITY OF MANGANESE BRONZE. (Sheet Metal ; Rods and Bolts.) NOS. LOADS ELONGA- TION. Yielding. Breaking. Tons per Kgs. per Tons per Kgs. per Per sq. in. sq. cm. sq. in. sq. cm. cent. 4,766 14.0 2,204 24-3 3,817 8.7 Cast in metal mould. 4,767 12.6 1,984 29.0 4,567 31-8 Ditto and forged. 4,768 14.0 2,204 22. 1 3.480 5-5 Ditto. 4,769 I" .2 2,079 28.8 4,535 35-3 Ditto and forged. ^ 1 4,77 16.8 2,645 2 3 .6 3-8 Cast in metal mould, slight flaw *o in specimen. c 4,771 12.0 1,890 30-3 4,772 25.7 Cast in metal mould and forged. |- rt ROLLED RODS. 1 6,536 6,545 II. O 16.6 1,732 2,615 29.0 4,567 4,835 44-6 20.7 Mild, for ships' bolts and rivets. High, for Engineers' bolts, 6,546 14.6 2,299 30.0 4,725 26.2 pump rods, etc. Medium. 6 ,547 34-4 39-6 6; 237 ii. 6 Cold rolled. AREA OF SPECIMENS, 0. 133 INCH. LENGTH OF BREAKING PART, 2 INCHES. {7,364 13.8 2 , I 73 28.57 4 54 28.7 Pulled in direction of fibre. 7,365 14.06 2,205 28.46 4488 23.2 Across fibre. 7,369 14.06 2,205 3-!3 4 740 47-8 With fibre. 7,372 14.8 30.78 4 850 Across fibre. 7,374 16.7 2,630 30.1 4740 28.8 With fibre. STRENGTH OF BRONZES. 317 Manganese bronze, tested by transverse stress, has been found to possess great strength, flexibility, and toughness. The following are figures given the Author by the inventor, as obtained by tests made in presence of the Inspector to the British Admiralty, January, 1881 : TABLE LVII. TRANSVERSE STRENGTH OF MANGANESE BRONZE. [Length, i foot (0.3 m.) ; Section, i in. (2.54 cm.) square.] LOAD AT MIDDLE OF BAR. Elastic Limit. At Rupture. Lbs. 2,688 1,232 Kgs. 122 56 Lbs. 6,048 2,912 Kgs. ' 275 132 Gun (Copper-tin) Bronze 195. Manganese Bronze tested by Impact, resisted the blow as shown in the following table, furnished the Author by the inventor ; 3l8 MATERIALS OF ENGINEERING NON-FERROUS METALS. i i trt .3 ~ * s aj O "^ \0 M M ^ 4 <*% H N o ro -OK ? * ? moo N STRENGTH OF BRONZES. 319 The wrought iron was of three grades ; the gun-metal was partly (Nos. I, 2, 3), of usual good quality, and partly (Nos. 4, 5) specially made for the test of copper, 16, tin, 2, and copper, 16, tin, 2%. The manganese was of several grades. No. 6 was annealed. 196. Copper and Iron, in the proportions varying from copper, 93. 5, iron, 6.5, to copper, 96, iron, 4, was tested by M. Riche,* and the alloy compared with copper, as below, TABLE LIX. TENACITY OF FERROUS COPPER. Elongations in millimetres corresponding to loads in kilogrammes. NAME OF METALS. * fc i\ li. 94 95 in 98 92 92 97 97 81 5 800 0.5 1-25 25 0.25 0.25 1,000 1,100 . is 0.5 0.5 3.0 4.5 5.0 U) 0.25 0.25 0.25 0.25 1,200 5 0.5 5.5 1,300 (t) o-S 6.0 1,400 1,500 i, 600 1,700 Copper of commerce, melted . . Copper of commerce, rolled. . Pure copper, melted Pure copper, melted 0-5 0-5 0.5 o-5 Copper and iron, melted Copper and iron, melted Copper and iron, melted ... . Copper and iron, melted Pure copper rolled 2 2 4-5 4-5 0.25 0.25 o 75 0.50 '5 2.O 2-5 3-o () 3-5 3-5 4-5 4-5 ft 90 Copper and iron, rolled Copper and iron, rolled NAME OF METALS. *g -- 1,800 1,000 2,000 2,100 2,200 2,300 2,400 2,500 2,600 2,700 2,800 Copper of commerce, Copper of commerce, rolled 0.5 0-5 1-5 2-5 4-5 5.5 .... .... Copper and iron, melted. Copper and iron, melted. 2 2 4-5 5-5 7.0 2.5 8.5 (I) 10. "5 15.0 Copper and iron, melted. Pure copper, rolled Pure copper, rolled 4-5 0.25 0-5 0.25 12.0 16.00 x.o 1. 20 '75 8-5 4.0 0.25 i.S 2.0 3-0 4.0 4-5 8.75 8.0 * (Ann. de C/iim. et de Phys., 4 strie, t. xxx., Nov., 1873, 26.) f The test was arrested because a blowhole was formed in the sample. \ The broken section presents blowholes. At i, 600 kilogrammes one lug of the piece was broken, I The sample broke without the two pieces being entirely separated 32O MATERIALS OF ENGINEERING NON-FERROUS METALS. NAME OF METALS. Per ct. 2,900 3,000 3,100 3,200 3,3 3,4oo 3,5oo 3,6co Breaking load. &. *s I* C/3 >, 1 Q Copper of commerce, melted Kilog. Kilog. Copper of commerce, rolled 2,300 1,300 1,000 11.711 8.039 Pure copper melted Copper and iron, melted Copper and iron, melted Copper and iron, melted Copper and iron, melted Pure copper rolled 2 2 4-5 4-5 26.086 2,800 2,300 2,300 3,500 3,600 28. 65 28.220 25.842 39-772 40.000 8.879 8.904 8.891 Pure copper, rolled Copper and iron, rolled. Copper and iron, rolled . 4-5 4-5 0.25 o.S o.S I.O 0.25 2-5 o-75 2-5 5 4-75 3-5 9.0 OBSERVATION. The melted copper (Nos. i, 3, 4) contains blowholes which destroy its tenacity. It elongates under light loads, and breaks, also, under a small load. The copper acquires a certain tenacity by rolling. While the resistance of melted copper is from 10 to 12 kilograms per square millimetre, that of the same copper attains, by rolling, 25 to 28 kilo- grams. The ductility is less, and the elongation becomes no longer evident under loads of i, 800 kilograms. finding a decided gain of strength and hardness with no loss of malleability. The same metals subjected to the action of a punch, were indented in the proportions, cast copper, 2.5 ; rolled copper, 1.5 ; with 0.03 iron, cast, i.i ; rolled, 0.9. , 197. The Copper-Tin Alloys, which, as has been stated, furnish a very large number of the best bronzes and engi- neers' compositions, and which are extensively used in every department of construction and the arts, had never been sys- tematically studied until the investigation was made by the U. S. Government Board upon a plan prepared, proposed, and carried out at the request of that Board, by the Author. Earlier investigations had been confined to a few familiar compositions, and it was only when appropriations made by the Congress of the United States could be applied to such a research that it became possible to determine the method of variation of strength, elasticity, and ductility, and of spe- cific gravity, and other properties, with variation of compo- sition throughout all the possible proportions of copper and tin alloys. In the research to be described the principal as- sistant employed by the Author was Mr. William Kent. S TRENG TH OF BRONZES. 3 2 1 This investigation of the strength, ductility, and other properties of all alloys of copper with tin was made in the Mechanical Laboratory of the Stevens Institute of Technol- ogy, in the years 1875-1878, for the Committee on Alloys of the United States Board appointed to test the useful metals of the United States, and the facts and data here to be given are mainly condensed from the reports made to that board * and the notes taken by the Author. This work was supple- mented by private investigations, of which an account will also be given. The intention in the work here to be described was, not to determine the character of chemically pure metals, melted, cast, and cooled with special precaution, but to ascertain the practical value of commercial metals, as found in the markets of the United States, melted in the way that such alloys are prepared in every foundry for business purposes, and cast and otherwise treated in every respect as the brass-founder usually handles his work; and to determine what is the prac- tical value, to the brass-founder and to the constructor, of commercial materials, treated in the ordinary manner and without any special precaution or any peculiar treatment. The result was the complete exploration of a broad and most important field of which almost nothing was previously known. The whole field having been explored the useful alloys are proven to occupy but a limited portion of its great ex- tent, and it has been now shown that a comparatively narrow band, extending from ordnance-bronze, on the one side of this triangular territory, to Muntz metal, on the other, contains all of the best of the generally useful alloys. This small por- tion of valuable territory having been pointed out and de- fined, its more minute study was left for future investigators. The reader should make a careful study of the graphical * Executive Document 98, 45th Congress ; Ex. Doc. 23, 40th Congress, 2nd Sessions ; 1878-1881. In the text of the report will be found a statement of the more important facts determined, and the tables appended contain all the results of observation. The whole forms a collection of facts that will probably repay a vastly more complete analysis and more careful study than it has yet been pos- sible to give them. 21 322 MATERIALS OF ENGINEERING NON-FERROUS METALS. representation of the results of the research on the alloys, as presenting most completely and satisfactorily the character- istics of the metals used. The researches consisted of an investigation of the proper- ties of the alloys of copper and tin, cast in the form of bars about 28 inches (71.1 cm.) long and I inch (2.54 cm.) square in section, prepared from the commercial metals, only ordi- nary precautions being taken to secure good castings. It was desired to learn also the laws which connected these proper- ties with the proportions of the component metals, and whether alloys mixed in simple proportions of the chemical equivalents of the component metals possessed advantages over other mixtures. 198. The Metals used were the best Lake Superior cop- per and Banca tin : they had the following compositions : INGOT LAKE SU- PERIOR COPPER. INGOT BANCA TIN. Metallic iron o 013 Metallic zinc. . . . None U -UJD Metallic silver o 014 None. Metallic antimony . . None Metallic cobalt Metallic bismuth Metallic nickel. Metallic lead Trace Metallic manganese Metallic molybdenum . . Metallic tungsten Metallic copper OQ 4.2O None Metallic tin ... QO O78 Suboxide of copper O ^^7 yv-y/ Carbon 0.04. 1 Matter insoluble in aoua regia Trace 100.025 100.013 199. Alloys Tested. The following table gives the com- position of the alloys made, according to their atomic pro- portions and percentages of original mixture, and according to chemical analysis after test. STRENGTH OF BRONZES. 323 TABLE LX. ALLOYS OF COPPER AND TIN. FIRST SERIES. Composition by Original Mixture and Analysis. NUMBER. ATOMIC PROPOR- TION. PERCENTAGE BY ORIGINAL MIX- TURE. MEAN PERCENT- AGE BY ANALY- SIS. MEAN SPECIFIC GRAVITY. Cu. Sn. Cu. Sn. Cu. Sn. j I 96 48 24 o i i i i i i i 5 i 7 2 3 5 i 4 5 2 3 4 5 12 4 8 9 6 I 100 98.1 96.27 92.80 90.00 86.57 80.00 76.32 70.00 68.25 65.00 61.71 56.32 51.80 47-95 44-63 41.74 39-20 34-95 28.72 24.38 21. IS 15.19 II.S4 9.70 4-29 I. II 0-557 O i-9 3-73 7.20 10.00 13.43 20.00 23.68 30.00 31-75 35-co 38.29 43-68 48.20 52.05 55-57 58.26 60.80 65-05 71.28 75.62 78.82 84.81 88.16 90.30 95-71 98.89 99-443 100 8.487 8.564 8.649 8.694 8.669 8.681 8.740 8.565 8.932 8.938 8.947 8.970 8.682 8.560 8.442 8.312 8.302 8.182 8.013 7.948 7.835 7.770 7.657 7-552 7.487 7.36o 7.305 7.299 7.293 2 ... 97.89 96.06 92.11 90.27 87.15 80.95 76.64 69.84 68.58 65-34 62.31 56.70 51.62 47.61 44-52 42.38 3^-37 34-22 25-85 23-35 20.25 15.08 11.49 8-57 3-72 0.74 0.32 1.90 3.76 7.80 9-58 12.73 18.84 23-24 29.89 31.26 34-47 37-35 43-17 48.09 52-14 55-28 57-30 61.32 65.80 73-80 76.29 79 63 84.62 88.47 91-39 96.31 99.02 99.46 a c 6 .. ... 12 7 8 6 IO 4 II 12 3 12 2 12 3 6 I 3 3 o 11 14. 16 17 . 18 IQ 21 24 25 26 . . 27 28 2Q 324 MATERIALS OF ENGINEERING NON-FERROUS METALS. SECOND SERIES. NUMBER. COMPOSITION OF ORIGINAL MIXTURE. MEAN COMPOSITION BY ANALYSIS. MEAN SPECIFIC GRAVITY. Copper. Tin. Copper. Tin. OJ 97.5 92.5 87.5 82.5 77-5 72-5 67-5 62.5 57-5 52-5 47-5 42.5 37-5 32.5 27-5 22. 5 17-5 12.5 7-5 2.5 2.5 7.5 12-5 17.5 22.5 27-5 32-5 37-5 42.5 47-5 52.5 57-5 62.5 67-5 72.5 77-5 82.5 87-5 92 5 97-5 99.09 94.10 88.40 82.72 77-56 72.89 67-87 62.42 57-87 53-46 47-27 43-99 37.10 30.76 26.62 22. IO 16.70 u.68 6.05 2. II 0.87 5-43 n-59 17-33 22.25 26.85 32-09 37.48 42.05 46 54 52-72 55-91 62.90 69.19 73-18 77-58 83-23 88.25 93-77 97-68 32 8.684 8.647 8.792 8.917 8-925 8.907 8-956 8.781 8.643 8.445 8-437 8.101 7-931 7-9 T 5 7-774 7.690 7.542 7.419 7-343 VA je 36* . q7 <*8. . 3Q . AQ 4.1 42 4. "3 44. 4.^ . . 46 4.7 48.. 4Q CO 200. Temperatures of Casting. The following are the temperatures at which some of these alloys were poured into the ingot-moulds. They vary irregularly, but show a general decrease from a maximum for alloys richest in cop- per to alloys containing most tin. These temperatures are evidently not those of fusion of the several alloys, but are somewhat above in all cases, and are several hundred degrees above the melting points, usually. The determination was made by pouring a small portion of molten alloy into a known weight of water, noting the rise in temperature of the latter, and, from it, calculating the loss of temperature of the alloy. * Second casting ; first broke in emery planer. STRENGTH OF BRONZES. TABLE LXI. ESTIMATED TEMPERATURES OF CASTING. 325 COMPOSITION BY K a j < TEMPERATURES OF y E CALCULATED RELA- ORIGINAL MIX- 5 WATER, CENTI- 8 TIVE TEMPERA- TURES. s GRADE SCALE. s . (f, H TURE. NUMBER. b. < tm O O u , 8 = i I X X o 3 "c3 Gf H -Ld li & u g I 1 1 i 1 1 1! Gram. 0*r. 31.. - - 97-5 2.5 907 74 8-3 22.8 14-5 0.004177 1909.9 3469.8 33- 92.5 87.5 7-5 12.5 907 907 101 12.8 16.7 %'* 18.9 26.1 0.092231 0.090285 1871.9 1802.6 3401.4 3276.6 34-- 82.5 17.5 907 362 9-4 60.0 50.6 0.088:39 I495-I 2723.0 11" 77-5 22.5 907 225 15-0 47 3 32-3 0.086393 1554-5 2829.2 36.. 72.5 27-5 907 157 "7 : 33-3 21.6 0.084447 1511.8 2751.8 37-- 67-5 32-5 907 97 u.i 26.1 i5-o 0.082501 1726.2 3148.8 38.. 62.5 37 5 97 177 10.6 31.7 21. I 0.080555 '373-9 2503.4 39- 57-5 42-5 907 129 17.2 32.8 15.6 0.078609 1428.0 2602.4 40.. 52.5 47-5 907 214 8-3 35.0 26.7 0.076663 15^1.1 2751.8 41.. 47-5 52-5 907 216 12.2 5-5 38.3 0.0747^7 2205.0 4001.0 42.. 43- 42-5 37-5 57-5 62.5 907 907 328 293 9-5 13-9 47-2 38.9 37-8 25.0 0.072771 0.070825 1063.8 1131 7 I 945-4 2067.8 44-. 32-5 67-5 007 255 8-9 32-2 23-3 0.068879 3192-8 : 27-5 22.5 72.5 907 85 277 7-8 12.2 18.3 38-9 10.5 26.7 0.066933 0.064987 1701.6 1382.7 3093.8 2519.6 47.. 17-5 82.5 907 241 '5-5 37-2 21.7 0.063041 2427.8 48.. 12.5 87-5 907 104 14-4 22.7 8-3 0.06:055 1211.9 22II.8 49- 7-5 92.5 907 240 18.9 33-3 14.4 0.059149 956.5 1752.8 5 2-5 97-5 907 154 20.5 27.2 6-7 0.057203 725.3 1337-0 The test-pieces were usually cast in iron moulds to secure rapid cooling. 201. External Appearance of the Bars. The following were characteristic features of the bars after casting : (i) A regular gradation in color took place from bar No. I, all copper, down to No. 8, 76.64 copper, 23.24 tin, the pol- ished surface of which was light golden yellow, and a regular gradation in hardness, No. 8 was filed with great difficulty. * In casting bar No. 32 (94.10 copper, 5.43 tin), while pouring the metal into water for the temperature test, an explosion took place which broke the wooden vessel holding the water, and threw water and metal about with great violence. No. 30 was cast at a dazzling white heat. On pouring a small portion into water to obtain the temperature, a severe explosion took place, and this was re- peated every time that even a drop of the molten metal touched the water. After the metal remaining -in the crucible had cooled considerably, it could be poured into water without causing explosions. It might be supposed that the result of casting at high temperature would be to make .No. 30 a bad bar, as this seems to be indicated by the experiments of Major Wade on gun-metal. The result, however, showed the contrary, as it proved to be equal to any bars cast. 326 MATERIALS OF ENGINEERING-NON-FERROUS METALS. (2) A sudden change of all properties took place at bar No. 9 69.84 copper, 29.89 tin. This bar was silver-white in color, and could not be scratched with a file. Pieces broken off showed a conchoidal fracture. No. 10 68.58 copper, 31.26 tin was similar to No. 9, and No. II 65.34 copper, 34.47 tin but little different. (3) Another change of color and properties occurred at No. 12 62.31 copper, 37.35 tin which bar was of a dark bluish-gray color, and the fracture similar to that of granite or other hard rock. This was the most dense alloy of the series. No. 13 56.70 copper, 43.17 tin was similar to No. 12, but lighter in color and a little softer. (4) Bar No. 14 51.62 copper, 48.09 tin was peculiar in showing a marked difference in the two ends of the bar. The upper end was like bar No. 12, while the bottom was of a lighter color, granular fracture, and so soft that it could be cut with a knife like a piece of chalk. (5) A change between bars No. 14 and No. 20 25.85 copper, 73.80 tin occurred gradually, the bars becoming whiter and softer, and the appearance of fracture changing from rough and stony to crystalline or granular. No. 20 could be cut with a knife, giving a short chip which had slight cohesion. From No. 20 to No. 29 (all tin) the soft- ness increased gradually, No. 21 giving a malleable chip on being cut. From No. 24 to No. 29 the appearance of all bars was much the same, differing slightly in hardness, and scarcely at all in color. No. i to No. 8 were likely to prove of value where strength was required, and bars No. 9 to No. 1 8, inclusive, were de- ficient in ductility as well as in strength, and for all practical purposes (except, perhaps, extremely limited use for special purposes, as speculum metal) worthless, Nearly all of the bars appeared to be good castings. 202. The Behavior of the Alloys under test was care- fully observed and a journal kept. Thus when tested by transverse stress : Bar No. 7 (80.95 copper, 18.84 tin), the strongest of the series/showed little ductility, breaking after a deflection of - STRENGTH OF BRONZES. $2? half an inch. From No. 8 to No. 13 (23.24 to 43.17 tin) in- clusive, there was a regular and rapid decrease, both in strength and ductility, the latter being the weakest bar of the series, showing only about * g^th of the strength of No. 7 and a de- flection of only 0.0103 inch. This bar gave trouble in cast- ing by breaking in the mould. Bar No. 9 (69.84 copper, 29.89 tin), which, in appearance, differed remarkably from No. 8 (76.64 copper, 23.24 tin), had less than f ths of its strength and less than th of the strength of No. 7, which latter differed only 10 per cent, from it in composition by original mixture, or 1 1 per cent, by analysis. Bars No. 14 to No. 20 (48.09 to 73.80 tin) inclusive, showed irregular variation in strength and ductility, but all of them were worthless, the best having only about |th of the strength of the maximum, and a deflec- tion of only o.i 23 inch before breaking. Bar No. 21 (23.35 copper, 76.29 tin) showed considerably greater strength and ductility than any of the series between No. 8 and No. 20, and greater strength than any from No. 8 to No. 29 (all tin), giving what may be called a second maximum point of strength in the series. This bar had a cavity extending throughout nearly its whole length, No. 21 to No. 24 (76.29 to 88.47 tin) had higher strength than those above and below them in series, showing that the second maximum point of strength is approached by bars having a difference of over 10 per cent, in composition. From No. 25 to No. 29 (91.39 to loo tin) there was a somewhat ir- regular decrease of strength but a great increase of ductility, bar No. 29 (all tin) showing the maximum ductility of the series and a second minimum in strength. Bars No. 26 to No. 29, inclusive, bent without breaking, as did those from No. 2 to No. 6(1.90 to 12.73 tin) at the other end of the series. With reference to the relation of the elastic limit to the ultimate transverse resistance from bar No. I to No. 7 in- clusive, the apparent elastic limit occurred at from 35 to 65 per cent, of the ultimate resistance. At No. 8 this limit ap- proached nearly, if not quite, the ultimate resistance ; and from No. 9 to No. 18 (29.89 to 61.32 tin) jnjclnsive^tfee two UNIVERSITY 328 MATERIALS OF ENGINEERING NON-FERROUS METALS. coincided, z>., the elastic limit was not reached till the bar broke. From No. 19 (34.22 copper, 65.80 tin) to the end of the series (all tin) the elastic limit was again reached before fracture, the ratio decreasing to No. 22 (20.25 copper, 79.63 tin), and then remaining appreciably constant at from 20 to 30 per cent, to the end of the series. The relation which the composition bears to the mechani- cal properties of strength, ductility, and elastic resistance is thus defined with tolerable exactness. Bars from No. I to No. 8, inclusive, had considerable strength, and all the rest were worthless for all purposes where strength is required. The dividing line between the strong and the brittle alloys is precisely that at which the color changes from golden yellow to silver white, viz., at a composition containing between 24 and 30 per cent, of tin ; alloys containing more than 24 per cent, tin are comparatively valueless. The journals of other tests give very similar records to those just quoted, and confirm, generally, the deductions which are made from transverse tests. Of the two bars of copper, No. I was spongy and weak, as it was cast in sand ; No. 30 was strong arid ductile. In tests by compression, many pieces were compressed to less than one-half of their original lengths, the resistance to further compression always increasing. When bending took place, the piece would, in some cases, take such a position as to gradually diminish in resistance, the pressure-plates touching only on the edges of the upper and lower surfaces of the piece. The actual ''crushing strengths" of the ductile metals, therefore, cannot be stated ; but, for purposes of comparison, the crushing strength is assumed to be that which corre- sponds to a compression of one-tenth of the original length. In the table, therefore, the figures in the column headed " crushing strength " represent, in the cases of ductile metals, the loads per square inch necessary to produce compressions of 10 per cent, of the original lengths. All brittle alloys, and some possessing limited ductility, No. 8 (76.64 copper, 23.24 tin) to No. 1 8 (38.37 copper, 61.32 STRENGTH OF BRONZES. 329 tin) inclusive, broke suddenly when their maximum resist- ances were reached, and the figures for crushing strengths are, therefore, actual values. In these, the " total compressions produced by maximum load " are the calculated compressions at the instants of breaking. In other cases, the figures are total compressions actually given the pieces without breaking them and include the shortening of the piece by bending ; they are not the total amounts of compression which might have been produced had the test been continued further. By inspection and comparing the results with those of transverse, tensile, and torsional tests, some important facts are observed. Assuming that the crushing strength of a ductile metal is the load necessary to produce a compression of one-tenth, and that of a brittle metal the load actually causing fracture, it is noted that the maximum and minimum strengths are hot found in the compositions which exhibited maximum and minimum strengths by the other methods of test. It has been observed that the relative strengths of the alloys, as shown by the other three methods of test, are similar. This is not the case with compressive tests. The maximum crushing strength is given by No. 9 (69,84 copper, 29.89 tin), which gave results nearer the minimum under the other tests. The minimum strength is found in tin, which was superior to several of the brittle alloys in other methods of test, which alloys greatly surpassed it in tests by compression. The compression pieces, No. I (all copper) to No. 5 (90.27 copper, 9.58 tin), and No. 30 (all copper), give results nearly alike. From No. 6 (87.15 copper, 18.84 tin ) to No. 9 (69.84 copper, 29.89 tin), is a rapid increase. From this point a decrease takes place to No. 29 (all tin). This decrease is somewhat irregular. It would be necessary to make a number of tests before attempting to explain this irregularity, but it may be a peculiarity of these compositions, since No. 12 was different in color from both No. II and No. 15, and had the highest density of the series. Nos. I to 8 (all copper to 76.64 copper, 23.24 tin), inclu- sive, were turned in the lathe without difficulty, a gradually 33 MATERIALS OF ENGINEERING NON-FERROUS METALS. increasing hardness being noticed, the last named giving a short chip, and requiring frequent sharpening of the tool. The turned surface was perfectly smooth. The color varied from copper-red to light golden-yellow, gradually becoming lighter with increase of percentage of tin. Nos. 36 to 42 (43.99 copper, 55.91 tin) inclusive, were tested with their original section unaltered, as they were too brittle to be turned. All gave trouble in setting in the tension machine, their brittleness and hardness being so great that the grips of the machine would not firmly hold them. They usually broke in the grips, and the figures representing strength are in many cases too low. 203. Surfaces of Fracture. After the tests by transverse stress, pieces were cut from each bar showing the fracture. These pieces were examined by Prof. A. R. Leeds, who made the following report. No. I (all copper). Color, copper-red, altering by ex- posure to air into purple by film of suboxide, and into black by film of oxide of copper. Surface in part large vesicular, in part curvilinear fibrous. Maximum diameter of vesicles, 7 mm. ; maximum breadth of fibres, 1.5 mm.; length, 8 mm. No. 2 (97.89 copper, 1.90 tin). Color, red, slightly oxi- dized by exposure. Large and coarse vesicular ; maximum diameter of vesicles, 5 mm. No. 3 (96.06 copper, 3.76 tin). Color, bright reddish-yel- low, with faint traces of black oxide from exposure. Surface, small and finely vesicular. No. 4 (92.11 copper, 7.80 tin). Color, dull reddish-yellow. Homogeneous. Surface, finely arborescent. No. 5 (90.27 copper, 9.58 tin). Color, reddish-yellow, with spots of dark red and bright yellow. Surface, not homoge- neous, in part vesicular, in part finely fibrous. No. 6 (87.15 copper, 12.73 tin). Color, brass-yellow in part, in part bluish-white. Surface, not homogeneous, finely vesicular. Fracture, hackly. No. 7 (80.95 copper, 18.84 tin). Color, reddish-gray, with brass-yellow spots. Surface, reticulated fibrous. S TRENG TH OF BRONZES. 3 3 1 No. 8 (76.64 copper, 23.24 tin). Color, reddish-gray. Sur- face, faintly vesicular ; interior of vesicles brass-yellow. Fract- ure, irregularly curved. Lustre, dull. No. 9 (69.84 copper, 29.89 tin). Color, grayish-white. Sur- face, crystallization prismatic, diverging from centre. Fract- ure, of large curvature. Lustre, glistening. No. 10 (68.58 copper, 31.26 tin). Color, grayish-white, more white than the preceding. Surface, crystalline pris- matic, diverging from the centre. Fracture, of large curva- ture. Lustre, glistening. No. 1 1 (65.34 copper, 34.47 tin). Color, bluish-gray, show- ing yellowish spots in some lights. Surface, interruptedly crystalline. Fracture, coarsely rounded. Lustre, splendent. No. 12 (62.31 copper, 37.35 tin). Color, dark bluish-gray. Surface, laminated. Fracture, coarse hackly. Lustre, splen- dent. No. 13 (56.70 copper, 43.17 tin). Color, bluish-white. Surface, crystallization eminent ; crystals prismatic and diverging from centre. Lustre, splendent. No. 14 (51.62 copper, 48.09 tin). Color, bluish-white. Surface, crystallized, but not readily apparent. Fracture, coarse angular. Lustre, splendent. No. 15 (47.61 copper, 52.14 tin). Color, grayish-white. Surface, finely granular. Fracture, waved. Lustre, glistening. No. 16 (44.52 copper 55.28 tin). Color, grayish-white. Surface, laminated granular. Fracture, coarsely waved. Lustre, glistening. No. 17 (42.38 copper, 57.30 tin). Color, grayish-white. Surface, crystallization finely reticulated. Fracture, uneven. Lustre, glistening. No. 1 8 (38.37 copper, 61.32 tin). Color, grayish-white. Surface, crystallized, but not readily apparent. Fracture, coarse hackly. Lustre, bright. No. 19 (34.22 copper, 65.80 tin). Color, grayish-white. Surface, crystallization eminent, prismatic, and diverging from centre. Prismatic angle, 130. Sides of prism doubly striated, one set of striae parallel to edge of prism, the other at an angle of 47 with the former. Lustre, splendent. 3 3 2 MA TERIA LS OF ENGINEERING NON-FERRO US ME TALS. No. 20 (25.85 copper, 73.80 tin). Color, grayish-white. Surface, crystallization eminent, prismatic. Lustre, splendent. No. 21 (23.35 copper, 76.29 tin). Color, grayish-white. Surface, crystallized, but not readily apparent. Fracture, hackly. Lustre, bright. No. 22 (20.25 copper, 79.63 tin). Color, grayish-white. Surface, crystallization not large but eminent ; prismatic diverging from centre. Prismatic angle, 107. Lustre, splendent. No. 23 (15.08 copper, 84.62 tin). Color, grayish-white. Surface, crystallization, coarse with prismatic faces, divergent. Fracture, jagged. Lustre, splendent. No. 24 (11.49 copper, 88.47 tin). Color, grayish-white. Surface, crystallization finely reticulated. Fracture, hackly. Lustre, dull with bright reflections from scattered crystalline faces. Section, distorted. No. 25 (8.57 copper, 91.39 tin). Color, grayish-white. Surface, granular. Lustre, dull, with glistening points. Section, distorted with curved edges. No. 26 (3.72 copper, 96,31 tin). Color, grayish-white. Surface, rounded granular. Lustre, dull. No. 27 (0.74 copper, 99,02 tin). Color, grayish-white. Surface, usually crystallization feeble with undefined pris- matic faces. Lustre, bright. No. 28 (0.32 copper, 99.46 tin). Color, grayish-white. Surface, irregularly waved. Lustre, dull. No. 29 (All tin). Color, bluish or grayish-white. Surface, slightly vesicular at centre, prismatic at edges. Section, much distorted. Lustre, bright. The following description of the fractures by tensile stress was also recorded : No. I B (all copper). Color, copper-red, with a purple film of sub-oxide ; surface, in part large vesicular, in part crystalline, radiating toward edge. No. 2 A (97.95 copper, 1.88 tin). Color, copper-red ; sur- face deeply vesicular ; fracture, uneven ; lustre, dull, with bright points. Bar No. 2 B (97.83 copper, 1.92 tin). Color, copper-red, STRENGTH OF BRONZES. 333 inclining toward yellow ; surface, finely vesicular ; fracture, uneven ; lustre, dull, with fine bright points. Bar No. 3 B (95.96 copper, 3.80 tin). Color, reddish-yel- low ; surface, finely vesicular, the curved surfaces interrupt- ing; lustre, dull. Bar No. 4 B (92.07 copper, 7.76 tin). Color, yellowish-red in part, in part reddish-yellow ; surface, vesicular ; lustre, dull. Bar No. 5 A (90.11 copper, 9.66 tin). Color, yellowish- red ; surface, crystallization, fibrous, radiate, finely vesicular on faces ; lustre, dull. Bar No. 5 B (90.43 copper, 9.50 tin). Color, grayish-yel- ow ; surface, coarse vesicular ; fracture, jagged ; lustre, dull. Bar No. 6 A (87.15 copper, 12,69 tin). Color, bluish-white with bright yellow spots ; surface, confusedly vesicular; fract- ure, hackly ; lustre, dull. Bar No. 6 B (87.15 copper, 12.77 tin )- Color, reddish-yel- low, with bluish-gray points, producing a general impression of orange ; surface, broadly crystalline, with surfaces of pris- matic faces finely vesicular ; lustre, dull, with minute bright points. Bar No. 7 A (80.99 copper, 18.92 tin). Color, grayish- white with yellow points; surface, not apparently crystalline; fracture, coarse hackly ; lustre, dull. Bar No. 8 B (76.60 copper, 23.23 tin). Color, yellowish- gray ; surface, vesicular, with smooth intervening faces ; fract- ure, even ; lustre, shining. Bar No. 9 A (69.90 copper, 29.85 tin). Color, yellowish- gray to bluish-gray in different lights ; surface, broadly-bladed prismatic, and diverging from centre; fracture, smooth; lus- tre, splendent. Bar No. 10 A (68.58 copper, 31.26 tin). Color, yellow to bluish-gray ; surface, broadly-bladed prismatic and diverging from centre ; fracture, smooth ; lustre splendent. Bar No. 11 A (65.31 copper, 34.47 tin). Color, yellow to bluish-gray; surface, crystallized, but not readily apparent ; fracture, coarsely waved ; lustre, splendent. Bar No. 12 B (62.79 copper, 36.96 tin). Color, blue ; sur- face, coarsely waved and pitted ; lustre, splendent. 334 MATERIALS OF ENGINEERING NON-FERROUS METALS. Bar No. 13 A (56.28 copper, 43.11 tin). Color, bluish; surface, crystallization eminent, prismatic blades diverging from centre ; fracture, uneven ; lustre, splendent. Bar No. 14 A (62.27 copper, 37.58 tin). Color, bluish-gray in part, in part reddish-gray ; surface, crystallized but not readily apparent ; fracture, uneven ; lustre, dull. Bar No. 14 B (38.41 copper, 61.04 tm )- Color, bluish-gray ; surface, crystallized but not readily apparent ; fracture, coarsely waved ; lustre, splendent. Bar No. 15 B (47.49 copper, 52.29 tin). Color, bluish-gray to grayish white ; surface, waved ; fracture, irregular ; lustre, glistening. Bar No. 16 B (44.42 copper, 55.41 tin). Color, grayish- white ; surface, crystallized but not readily apparent, waved and feebly vesicular; lustre, glistening. Bar No. 17 B (38.83 copper, 60.79 tin )- Color, grayish- white ; surface, finely waved vesicular ; lustre, shining, with bright points. Bar No. 18 A (43.37 copper, 56.37 tin). Color, grayish- white ; surface, crystallization prismatic, with waved lines on prismatic faces; lustre, splendent. Bar No. 18 B (43.36 copper, 56.40 tin). Color, grayish- white ; surface, crystallized but not readily apparent, feebly vesicular ; fracture, irregular ; lustre, glistening, bright lines of reflection from crystalline faces. Bar No. 19 A (40.32 copper, 59.46 tin). Color, grayish- white ; surface, crystallization eminent, prismatic ; the pris- matic faces large and striated ; prismatic angle, 91 ; lustre, splendent. Bar No. 19 B (40.24 copper, 59.44 tin). Color, grayish- white ; surface, crystallization eminent, prismatic ; lustre, splendent. Bar No. 20 A (26.57 copper, 73.08 tin). Color, grayish- white ; surface, crystallization eminent, the faces in part prismatic, in part having an octahedral aspect ; lustre, splen- dent. Bar No. 20 B (25.12 copper, 74.51 tin). Color, grayish- white ; surface, crystallized but not readily apparent, waved STRENGTH OF BRONZES. 335 and feebly vesicular fracture, rough ; lustre, glistening, with bright surfaces of reflection. Bar No. 21 B (33 89 copper, 75.68 tin). Color, grayish- white ; surface, feebly crystalline and vesicular ; fracture, hackly ; lustre, glistening, with bright points. Bar No. 22 A (20.28 copper, 79.63 tin). Color,, grayish- white ; surface, crystallization eminent, prismatic faces irre- gular ; lustre, splendent. Bar No. 22 B (20.21 copper, 79.62 tin). Color, grayish- white ; surface, confusedly crystalline, with prismatic faces ; lustre, splendent. Bar No. 23 A (15.12 copper, 84.58 tin). Color, grayish- white, in part with yellow tarnish ; surface, crystallization eminent, broad prismatic faces, radiate ; lustre, splendent. Bar No. 24 B (11.48 copper, 88.50 tin). Color, grayish- white; surface, crystallized fibrous; fracture, hackly; lustre/ glistening, with bright lines of reflection from edges of crys- tals. Bar No. 25 A (8.82 copper, 91.12 tin). Color, grayish- white ; surface, irregular and feebly vesicular ; lustre, dull. Bar No. 26 B (3.74 copper, 96.32 tin). Color, grayish- white ; surface, fibrous, in part slightly vesicular ; lustre, dull. Bar No. 27 A (0.75 copper, 98.98 tin). Color, grayish- white ; surface, fibrous ; fracture, jagged ; lustre, dull. 204. Records illustrating the Methods and Results of this research are given on the following pages, in tabular form, selected from the mass of data recorded in the reports of the U. S. Board, to which reference may be made for other details. Those here given are representative of the work done on some of the best alloys discovered during the inves- tigation, but do not by any means include all the useful compositions, the data from which are included in the table of summaries of all methods of test there given. These tables of records cover the range from good bearing metal to bell- metal, and the figures given are fair averages for such alloys ; they fall considerably below figures attainable in larger work performed by trained workmen. 33^ MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXII. TESTS BY TENSILE STRESS. No. 4 A. Material : Alloy. Original Mixture : 92.8 Cu. 7.2 Sn. Analysis, 92. 14 11,7.84 Sn. Dimensions: Length, 5"; Diameter, 0.798". Load. Load per square inch. Elongation in 5 inches. ||| Load. Load per square inch. Elongation in 5 inches. c be III |il s Pounds. Poztnds. Inch. Pounds. Pounds. Inch. 5,100 10.200 , O.OI ,0020 14,610 29,220 o-37 .0740 8,000 10,000 10,760 16,000 20,000 21,520 O.O2 0.03 0.05 .0040 .0060 .0100 I4 Broke Diame 29,300 i inches fro ter of fractu o-39 m C end. red section, < .0780 3.730 inch. 11,410 22,820 O.O ) .0180 No blowholes. o Set 0.08 Tenacity per square inch of original sec- 11,900 12,800 23,800 25,600 O.II 0.14 .0220 .0280 tion, 29,300 pounds (2,090 kgs. per sq. cm.). Tenacity per square inch in fractured sec- 13^40 26,280 0.21 .0420 tion, 35,000 pounds (2,461 kgs. per sq. cm.). 14,000 28,000 0.27 .0540 No. 7 A. Material: Alloy. Original mixture: 80 Cu, 20 Sn. Analysis: 80.99 Cu, 18.9280. Dimensions : Length, 6" ; Diameter, 0.798". 91850 19,700 O.OI .002 Tenacity per square inch original section, 14.000 16,800 28,000 33,600 O.O2 Broke in .004 middle. 33,6^0 pounds 2,362 kgs. per sq. cm.). Tenacity per square inch, deducting blow- hole, 34,139 pounds (2.400 kgs. per sq. cm.). Diameter of fractured section, 0.7 08 inches. One blowhole, irregular-shaped, about o.io inch diameter. No. 33 B. Material: Alloy. Original mixture : 87.5 Cu, 12.5 Sn. Dimensions : Length, 5' Diameter, 0.798". 1,200 0.0025 .0005 24,000 0.0905 .0191 2,000 0.0052 .OCIO 200 o'.o665 3,000 0.0097 .0019 26,000 0.1040 .0208 4,000 0.0139 .0028 28,000 0.1271 0254 6,000 0.0206 .0041 200 0.1063 8,000 0.0275 .0055 30,000 0.1561 . .0312 200 o'.oooS (?) 32.000 0.2007 .0401 10,000 o 0330 '.0066 2OO o. 1811 12,000 0.0396 .0079 33,000- 0.2270 0454 200 0.0049 33,200 0.2432 i .0485 14.000 -473 .0094 16,000 0.0541 .0108 Broke in middle. 200 0.0200 Diameter of fractured section, 0.770 inch. 18,000 0.0623 .0125 Tenacity per square inch, original section, 20,000 200 0.0709 0.0421 .0142 33.200 pounds (2,334 kgs. per sq. cm.). Tenacity per square inch, fractured sec- 22,000 0.0793 .0159 tion, 35,648 pounds (2,508 kgs. per sq. cm.). STRENGTH OF BRONZES. 337 TABLE LXIII. TESTS BY COMPRESSIVE STRESS. No. 31. Material: Alloy. Original mixture: 97. 5 Cu, 2.5 Sn. Analysis: 99.09 Cu, 0.87 Sn. Dimensions: Length, 2" ; Diameter, 0.625". c.J. c.J. "" bo c ' j~ '*%* Load. Compres- sion. Load per square inch. r\ ** "* : Load. Compres- sion. Load per square inch. _o o Jl lal 111 u U Pounds. Inch. Pounds. Pounds. Inch. Pounds. 150 .0000 16,000 395 1 52,152 T 975 2.000 .00.8 6,519 .0009 18,000 .5176 58,671 .2588 4,000 .0093 13,038 .0046 20,000 6 1 ;6 65,188 .3078 6,000 .0302 J 9'557 i .0151 22,000 .7266 71,700 3683 8,000 .0609 26,075 .0305 24,000 .8483 78,228 .4242 10,000 .1077 32,595 0539 25,000 .8801* 81,485 .4100 12,000 .1662 .0831 14,000 .2601 ' 45,633 .1300 * Wedge cracked off at the top. No. 32. Material : Alloy. Original mixture: 92.5 Cu, 7.5 Sn. Analysis : 94.11 Cu, 5.43 Sn. Dimensions: Length, 2" ; Diameter, 0.625". 150 .0000 22,000 .458<. 71,709 .2292 2,000 .0000 6,5 J 9 24,000 SIS! 78.228 2575 4,000 .0000 13,038 26,000 .5778 84,747 .2889 6,000 .0002 19-557 .0001 28,000 .6303 91,266 3 J 97 8.000 .0108 26,075 .0054 3O,OOO .7000 97,780 3500 IO.OOO .0511 32,595 .0255 32,000 7499 104,303 -3749 I2,COO .1219 30,' 14 .0609 34.000 .8033 110,822 i .4016 i.t,coo .1937 45,633 .0968 36,000 .8447 117,341 .4223 16,000 .2648 52,152 .1324 38,000 .8918 123,860 .4459 18.000 33'-o 58,671 .1655 40,000 9330 130,379 < -4665 20,000 3951 65,188 .1975 No. 33. Material: Alloy. Original mixture: 87.5 Cu. 12.5 Sn. Analysis: 88.4oCu, 11.59 Sn. Dimensions : Length, 2" ; Diameter, 0.625". 150 .OOOO 24,000 3234 78,228 .1617 4,000 .OOIt = 3,038 .0007 26,000 3575 84.747 1783 6,000 .0058 19,557 .0029 28.000 .4019 91,266 .2009 8.000 .0:70 26,075 .0085 30.000 .4412 97.785 .2206 10,000 0374 3 2 ,595 .0187 32,000 4815 104,303 .2407 12,000 .0711 3Q, '*4 0355 1 34,ooo .5171 110,822 2585 14,00? .1166 45-633 .0583 ! 3^,000 5534 117,341 2767 16,000 1636 52.152 .0818 38.00-) 5905 123,860 .2952 18,000 20.000 .2102 .2564 58.6^1 65,188 .1051 .1282 40,000 42,000 .6234 .6^11 I 3-379 136,898 3"7 3305 22,000 .2991 7 I -79 I 495 j 44,ooo .6911 1 143,417 ! 3455 22 338 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXIV. TESTS BY TR AN VERSE STRESS. flo. 4. Material : Alloy. Original mixture : 92.8 Cu, 7,2 Sn. Dimensions : Length between supports, 22" ; Breadth, 0.997" \ Depth, 1.012". Load. Deflection, A . Set. Modulus of elasticity. - 4 /^ (/> +<> Load. Deflection, A. Set. Modulus of elasticity. E=-, ja (P+4) 4 A bd* Pounds. 6 10 20 30 40 60 80 100 o 125 150 175 200 O 22 5 250 O 275 300 o 325 350 375 400 o 425 450 475 o 500 525 550 575 o 600 o 650 700 Inch. 0.0008 0.0016 o . 0039 0.007 O.OIO 0.013 0.017 0.020 0.024 O.O29 0.034 0.041 0.045 0.052 0.057 0.059 0.063 o 066 0.072 0.075 0.079 0.082 0.087 0.095 O. IO2 0.106 0. 112 o. 124 0.137 Inch. Pounds. o 750 800 850 900 T 950 In 5 m. 1,000 In 5 m. o 1,050 tn 10 m. I,IOO In 10 m. o T,IOO In 3 m. 1,200 In 10 m. 1,200 1,250 In 10 m. In 30 m. 15" 30-" o 1,250 1,300 In 10 m. In 30 m. In 30 m. Break Modu Inch. 0.173 0.199 0.232 o 287 0.348 0.429 0.491 0.584 0.620 0.781 0.858 1.031 1-053 1.289 1.384 1.824 T -935 2.178 2.281 2.637 2.638 2.746 2.911 2.966 3.226 6.706 ng load, / us of rupt R Rm-- Inch. O.O2O 0.049 o. 116 -379 0.807 10,408,413 8,114,620 5,267,855 13, 396,335 O.ODO I2,8l3,22/ 0.000 o.oojS 3,314,847 12,583,801 o.ooo 0.000 13,274,439 I 3 ',8i 7 ,'8o3 2,240,640 1-549 14,263,420 2-343 Tray reach supports. = i, 35 opoui are, = 3,o74. 0.0016 0.0024 0.0032 0.0055 0.0095 13,677,484 I 3i4 6 4.3SS 1,223,372 ed bottom of ids. 3) = 48,731- 12,548,648 0.153 11,853,945 STRENGTH OF BRONZES. 339 TABLE LXIV. Continued. No 32. Material : Alloy. Original mixture: 92.5 Cu, 7.5 Sn. Dimensions : Length between supports, / = 22" ; Breadth, b = 0.956" ; Depth, d = 0.982". Load. Pounds. 10 20 120 1 60 200 3 240 280 320 360 400 3 1 600 Deflection. A Set. Modulus of elasticity. E- Pi * Load. Deflection. A Set. Modulus of elasticity. A bd^ 4 A bd* Inch. 0.0060 0.0104 0.0185 0.0278 0.0376 0.0472 o 0572 Inch. Pounds. 640 680 720 760 800 840 880 920 960 1,000 1,040 Bar ben Break i i of 3*' Inches. 0.2095 0.2365 0.2^67 0.6031 Inches. 0.0:55 6,357,759 8, 4^i, 7^5 9,384,450 9,967,673 10,281,341 10,564,538 10,70^,500 10,692,594 10,768,738 10,644,211 10,501,656 10,161,429 9,961,177 9,579, 1 7 l 8,087,663 7,957,281 6,030,003 3,900,466 0.0035 o 0413 0.0668 0.0769 0.0880 0.0983 0.1105 o . 6202 0.0427 1.3217 '.74 2.13 2.63 3.78 t to a defle ig load (or ') i, 080 po 0.0145 Beam sinks 1,380,404 0.1232 0.1389 o.i535 0.1719 0-1963 840,132 3.40 :tion of 8" without breaking, the load causing deflection inds. 0.0577 0.206=; Resistance decreased in 2 to 586 pounds. Resistance decreased in i h 48'" 10562 pounds. Rm = 2,718. No. 7. Material : Alloy. Original mixture : So Cu, 20 Sn. Analysis : 80.95 Cu, 18.84 Dimensions: Length between supports, 22" ; Breadth, 0.998" ; Depth, i.on. 100 125 J 5^> *75 200 O 225 250 275 300 3 3 2 5 350 375 400 425 450 475 500 o 525 550 575 600 625 650 700 750 800 o 850 o.02<; 0.028 -33 0.037 0.043 0.045 0.051 0.057 0.063 0.069 0.073 0.077 0.081 0.083 0.087 0.094 0.098 o. 03 o. 05 o. 14 0. 22 0.128 0.132 0.140 o-JSS 0.167 0.172 0.0024 K>,737,827 11,891,996 12,045,639 12,487,468 12,245,726 ,00 o 950 1,000 o 1,050 1,100 1,200 o 1,300 1,400 1,500 o 1,600 1,700 T Il6s< L In 15 h 1,520 ' ffift* Break Modul 0.184 0.192 0.201 O.2O9 0.219 o. 256 0.285 0.320 0.360 0-4 T 5 0.470 0.510 0-537 0.469 Broke i pound of ng load, i us of rupti R = -\ 26 Rm = 3,9 0.0103 12,681,589 0.012 12,893,200 o 013 0.026 0.039 0.055 0.075 0.099 0.126 13,012,118 12,139,743 11,810,161 12,855,428 0.0039 ",455,356 12,517,091 11,325,050 0.0047 12,874,176 10,783,714 9,976,527 9,355,254 9,202,114 0.0063 13,274,787 0.169 0.0063 12,779,097 o seconds after putting on the weight. 750 pounds, are, ^y(/ > + 3) = 56,7i3. 87. 0.0039 12,979,791 0.0063 12.426,896 j 340 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXIV. Continued. No. 33. Material : Alloy. Original mixture: 87.5 Cu, 12.5 Sn. Dimensions : Length be- tween supports, 22"; Breadth, 0.973"; Depth, o. 977". Load. Deflection. A Set. Modulus of elasticity, Pfi Load. Deflection. A Set. Modulus of elasticity. P*_ 4 A bd* 4*M Bounds. 10 20 40 80 120 160 200 3 240 280 320 360 400 3 440 480 520 560 600 640 680 720 760 800 840 880 920 960 Inches. 0.0042 0.0075 0.0125 0.0236 0.0322 0.0409 0.0508 0.0606 0.0701 0.0793 0.0890 0,0580 o. 1071 0.1168 Inches. Pounds. 1,000 Inches. 0.3245 Inches. 3 1,040 i, 080 1,200 1,160 1,200 I,2OO I,2 4 ! 1,280 1,300 j 1,320 0.3611 0-3959 0-4493 0.5122 0.5727 0.0910 9,387,752 9,969,873 0,603,633 1,478,087 I ,549, 8 9 I 1,618,503 i,7i7,949 1,838,275 1,869,273 ',974,171 8,002,946 6,147,034 0.0049 0.2827 0.5892 o- 6 475 0.7485 0.8111 0.8701 o 9892 0.0036 (?) 12,052,435 1,400 1,440 ,480 i ' S A ,500 ,630 ,640 ,680 , 7 3 3 1,700 Bar br Breaki Modul 1.1419 1.3032 1.4878 1.6700 1.8500 2.1000 2.4500 3. looo 3.5000 oke after a ng load, i, us of rupt "2.81" deflection of 700 pounds ure, R - -^ 20 Rm = 4,2 3,596,760 2,235, '79 1,424,927 0-1335 0.1461 12,127,844 12,047,936 O.OII2 0.1568 0.1678 0.1800 - I 933 0.2074 0.2269 0.2475 0.2716 0.2964 11,888,540 slowly. Beam sinks 0.0284 ",3i5,997 about 4". y -p = 60,403 Ibs. *6. 9,937,3 2 7 No. 34. Material : Alloy. Original mixture: 82.5 Cu, 17.5 Sn. Dimensions : Length be- tween supports, 22"; Breadth, 0,950"; Depth, 0.970". 1 20 160 200 10 240 280 320 360 400 10 440 480 520 560 600 10 720 760 800 Resistan 10 840 880 920 960 0.0316 0.0405 0.0481 0.0560 0.0646 0.0729 0.0834 0.0881 0.0940 o. 1027 0.1099 0.1174 0.1265 0.1340 0.1409 O.M73 0-1549 0.1631 ce decreas 0.1702 0.1790 0.1873 0-1959 11,659,056 12,129,260 12,765,982 I,ooo JO 1.040 ,080 ,120 ,100 ,200 ,240 ,280 1,320 1,360 1,400 10 1,520 1, 600 10 1 , 720 1, 800 1,840 Brok< 30 secoi after re Breal Modu 0,2060 .0,2157 0.2264 0,2377 0,2472 0.2614 0,2728 0.2852 0,3003 0,3175 0-333 0.3880 0,4393 o, S247 0,5757 0,6125 : suddenly ids after pi ading the c :ing load, i lus of rup< 14,903,838 0.0035 0.0098 14,802,137 13,158,079 I3,307,4 T 7 *3,476,957 i3-747,25 3 13,939,699 T 4, 371,235 14,349,611 14,526,967 14,644,993 14,562,305 14.663,731 14,817,235 15,007,180 15,063,694 !5,o59,3i8 to 788 pounds, 15,152,664 15,093,815 | 15,080,625 i 15,045,481 14,466,320 !3,495,466 0.0035 0.0436 12,055,389 0.0028 2d in i9 h 45 0.0047 0-0935 with a ringi atting on the leflection. ,840 pounds. ture, R = - - 2 I ^ = 4,6 1^,064,370 9,223,187 ng sound about strain, and just PI -- 2 = 67,930. 75- STRENGTH OF BRONZES. 341 205. Final Results. The following table exhibits the results of the whole investigation in a compact form which permits ready comparison of data. The average results obtained by test of the copper-tin alloys, enable the engineer to reach tolerably definite conclu- sions relative to their value in construction. The results are given as obtained by the four principal methods of stress. They are very variable, and this variability is due not only to the variation of composition of the alloys, but also to their differences of physical structure, and is, therefore, to some extent, accidental. General conclusions may, nevertheless, be deduced and the principal facts revealed by test, and these conclusions are also most unmistakably exhibited by the diagrams pre- sented in this and preceding articles. The figures given by the tests have been plotted in the form of curves having for their ordinate the resistance ob- served and for their abscissas the distortion of the given test- piece. These curves exhibit the method of variation of re- sistance with progressing change of form, and constitute " strain diagrams " which exhibit to the eye every important quality of the material. 342 MATERIALS OF ENGINEERING NON-FERROUS METALS, Q 5 * * ^ 8 COMPRES- SION TESTS. jo uoisu3;xg; uois jo c I M 8 r- pl ? M" o" M 1 8 8 8 8 8 o _6 6 _M_J o' o' o' o' o o o' o' o' 6 o' o' v-^ioroO V >O^O ioc jo uoissajdcuoo jo lunotuv spunod Sui-_jsru3 000-00 O oo ro -Suo jo saSEiuaojad 'uoii -Das p9.m:pTUj jo jo sjacd ui 'uopBxJubp JO S33BUI30J9d''}lUIll OH S3 bx>3 o I uop UOIJ XlptjsBp jo snjnpoj\[ S31JDUI f ^ JO UOIJ 3 j o j 9 q uoijoauap jo 'sured ui 'iftun oi ajrudru jo sn^npoj^ AilAVHD DIJIDHdS NV3W 'NOIXHOdOHJ DIWOXV MO' too Q Q O O \o vo O O f?i ^ oo t-Cvo" i-T c^^o" cT -4- '^o 10 w t, t^- ! J< & s ! : . I? & ;r sH M I 1 C -CCCC ")^ . QJ(]J^;^ 'ca : iffiffifQCQ o o o o o o *m l ot^ ^M- > .lOCJt^Oio .*oioOOOOO MM . . ro Th ro * m - Co^D O O .NMOOfl-O lOMD O .u->OO .rowiNHM O> j t^o O N IT) 0) CO M Ox 5- ^^O cC ro% cooooooooooooooooooooooooooococooo . o t^vo o MOO o M * * >r> -^ tx W O txVO N O O oo f^vo CJ 0) O t^.vo w O r^vQ n 000 00 000 00 00 CO tv t- ^ : : 3 : s 3 : : : 3 : : : 3 . -tj -uu -u u *CG ***C * "*C ' HONMCO-^-N coco co rovo M* t^ moo v STRENGTH OF BRONZES. i IH ci 1-4 ^- u M ci r*"> iovo vo * w f nOOOOOOOOOOOOOOOOOw ror,; OOO O ** row rn M rr> m f> < OOOOOOOOOOOOOOOOOOOOOOOOOOOOOHMNN 3-8 8 8 8888888888888888o'8'oi H, o ^-mONc^MVO ^- ^-oo oo . 10 moo ior*xmroto- rx^j-i-i w ? Cl O v8 O t~ tooo O. ro w E * i vo' vo' O t^.00* 00 t>. ro ->-OOOOO O.VO vonOOmciMOOioto r^-.OO vo-u-i-'*-'''-)-^-'*- 1 -^ 1 -'-' t-> fi M ~> M M o -- ~ w ri <- ^-vS CO-4-MNdvool-rOLOi^eeaCeCCC OOOOOOOOOOOOOOOO^wcici-^-ro tooo OOCJCJOOCJUO o o" o' o" o' o* o" o" o' o" o' o" o' o' o* o' o* o" o' o' o' o' o' o' f CxVQ fxw OIVO tOt>-O wVO -^Cl O W ^CO t-^CO C^ r^ C-OJ ^ -^J-VO to ^- to r}- M-OO O r^t^ovo r^M or^o O f-oo r~ O ^oo t-^vo M ooo oovo too Ovo M t^vo ro * <* t^ O t^ t-~ i-^ OOO vovO I^O i-i -4-OroM O " 1-vo -<*-^; o-^ci crrocTiH"rnroio -^vo" rCod vo to t^oo hTcTmo'd'od'o'io ovo'co' co -4- fo JOO O M n"^|-i-i r^t^t^Oto-^' tooo IH vo "* O O O ~ ~ O OOO t^. t^vo vo toto^t-^-n^rorOd Cl Oto^^-rOTCi^MMOOO OCO r>. 2 . Tt^o-^^^^.^TT^.-*" ci N' to to tC. M ro - - 10 i) o t s, 8 a s s;s a 8 W 10 IXOO C4 f^ I*x00 0* (M 10 1^00 O N POfif*. ro-*t-^t i '<*-Tfioioioio io\O NO v c : c '. c c '. c ' c c '. C/3 -in -C/2C/5 C75 C/5C/5 -C c/3 'c/3 ^tn '-r'o 3 3 v r. t? '. c '. c c c C/2C/3 -C/) -CflCflCfl co n-, HI co M * H w T*- M * M IH ^- M * u -^- o N" ci %- ci v ci ci * N 10 ci ci N II li - 5 111 8t 343 344 MATERIALS OF ENGINEERING NON-FERROUS METALS 206. Strain-Diagrams, obtained from tests determining tenacity of the bronzes, are given in the accompanying figure as derived from experiments upon the first series of copper- tin alloys, No. I, pure copper, to 29, pure tin, inclusive. The curves marked A are from the upper end of the bar and B from the lower end. These curves may evidently be divided into three classes : viz., those which are very rigid and brittle, as 7 A, 7 B (cop- per, 80, bell-metal), those which are very ductile and mallea- ble but soft and weak, as Nos. 26 to 29 (tin, 95 to 100) inclusive ; and those which combine strength and ductility and possess, therefore, great resilience, as Nos. 2, 3 and 4 A (copper, 93 to 98, gun-metals). All intermediate qualities may be obtained, but these are typical and the most valuable of these compositions are evidently, for general purposes, those belonging to the last class, and of which the strain- diagrams lie between the extreme qualities, one set of which He near the axis of abscissas, while the other set lie nearer the axis of ordinates. For some purposes, as when, for example, it is desirable to secure a high elastic limit as well as moderate toughness, alloys like ordnance bronzes, Nos. 4, 5, 6 (copper, 86 to 93), which are stiff and strong, although not very ductile, may be chosen. Cases may even arise, although certainly not often, in which the rigidity of bell-metal, No. 7 (copper, 80), may make that alloy valuable in consequence of its high elastic limit, notwithstanding its great deficiency in ductility. 207. The Tenacities of the valuable class of these metals range not far from 30,000 pounds per square inch (2,109 kilg s - per sq. cm.), the strength increasing somewhat with the pro- portion of tin up to 1 8 per cent. Within that range, the expression T 30,000 + i ,000 /, in which T is the tenacity and / the percentage of tin, may be taken to represent a maximum which selected materials STRENGTH OF BRONZES. 345 346 MATERIALS OF ENGINEERING NON-FERROUS METALS. and careful fluxing should enable the engineer to secure. Two-thirds these values, or T 20,000 + 700 t, should be expected as a minimum. In metric measures, the two values would become, nearly, T 2,100 + 700 /, as a maximum ; T m = 1,400 + 500 t, as a minimum. The ductility should be at least 10 per cent, for the best alloy, and must be expected to be too slight to be counted upon when the proportion of tin exceeds 20 per cent, unless this percentage rises to a very high figure, as from 90 per cent, upward, when it again becomes considerable. The modulus of ultimate resilience obtained by multiply- ing two-thirds the tenacity by the extension of a piece one unit in length should be, in foot-pounds, for the more valuable alloys, not less than 3,000 foot-pounds or 250 foot-pounds per cubic inch (or not far from 2.5 kilogram- metres per cubic centimetre) for good materials, and two- thirds this value for ordinary work. The elastic resilience is not to be expected to exceed 5 foot-pounds per cubic inch (or about 0.05 kilogram-metres per cubic centimetre). The plate only exhibits one of the two sets of strain- diagrams, and a less favorable representation of the quality of these alloys than would be obtained from tests of specially prepared and carefully fluxed specimens, such as may be secured when needed. The alloys containing from 75 down to 25 per cent, copper are stone-like, inelastic, brittle and worthless for the work of the engineer, their strain-diagrams are straight lines and do not appear in the figure. A moderately well defined "elastic limit" is seen to exist with many of the harder of these alloys, as, e.g., Nos. 3, 4, 5 and 6 (copper, 85 to 95). 208. Compression Strain-diagrams are exhibited in Figure 10 which are obtained from the same set of alloys as STRENGTH OF BRONZES. 347 s f a MATERIALS OF ENGINEERING NON-FERROUS METALS. were used in the preparation of the tension diagrams shown in the preceding illustration. The alloys do not hold precisely the same order in com- pression as in tension ; but the same general facts are observable. The most resilient (ultimate) metals are as above, Nos. I to 7 and 30 (copper, 80 and upward) ; the most malleable are Nos. 25 to 29 (copper, 10 or less), and the most rigid are Nos. 9, 10, 11 (copper, 65 to 70). No. 9 (copper, 70) excels enormously in strength and in elastic resilience, and in elastic resistance ; No. 8 (copper, 75) is a very resilient alloy, also ; Nos. 6 and 7 (copper, 80 to 86) excel in ultimate resilience, or power of resisting shocks great enough to deform the piece. Gun-bronze, No. 5 ( c p- per, 90), is evidently one of the best of these alloys. Some of the singular variations seen in several of the diagrams are probably due to accidental peculiarities of de- formation of the test piece ; possibly all may be so. Elastic'limits are not as well defined here as in the tension diagrams, and, in the hard alloys, are either obscure, as in No. 7 (copper, 80), or coincide with the point of rupture, as in Nos. 9-15 (copper, 45 to 70). Comparing the two sets of diagrams, it is seen that, for members in tension, for bolts, sheet metal, ordnance, in fact for the majority of all common purposes, the best alloys are those lying very near the copper-end of the series and con- taining from 2 to 10 per cent, of that metal, and the less as the method of attack includes the action of shock to a greater extent. For compression, more tin is advisable (10 to 15 per cent.) if shock occurs, and it may be justifiable to reduce the copper to 70 per cent., even if the load is applied absolutely without jar, and maximum tenacity, simply, is sought. 209. Transverse Tests of the copper-tin alloys give strain-diagrams such as are seen in Figure II. Compositions approaching copper, 80, tin, 20, exhibit the greatest strength under this form of load. Those having less tin (6 to 10 per ceni..) as Nos. 4, 5 (copper, 93 ; copper, 90), are evidently vastly better to resist the shock of suddenly applied loads and safer against accident ; STRENGTH OF BRONZES. 349 35O MATERIALS OF ENGINEERING NON-FERROUS METALS. while those consisting principally of tin are soft and very ductile and malleable, as already seen. 210. Comparison of Resistances. By inspection of the curves, it will be seen that the curves of tensile and torsional strength agree very closely, the torsion curve being laid down to such a scale that one foot-pound of torsional moment has the same measure as 200 pounds tenacity. The curve of transverse strength is, in form, similar to those of tension and torsion (one pound modulus of rupture corresponding to one pound tenacity), but the ordinates of the curve are usually much greater than in the two latter. The curve of compression strength is very unlike either of the others. Laid down to the same scale as that of tenacity, the ordinates of the curve are much higher, showing that the compression resistances of the copper-tin alloys are much greater than their tenacities. The maximum compression strength is reached by one of the brittle alloys, the tenacity of which was not far from the minimum. The tensile and compressive resistances of the alloys are in no way related to each other ; the torsional strength is very nearly proportional to the tensile strength. The trans- verse strength may depend, in some degree, upon the com- pressive strength, but it is much more nearly related to the tensile strength, as is shown by the general correspondence of the curve of transverse with that of tensile resistance. The modulus of rupture, as obtained by the transverse tests, is, in general, a figure between those of tensile and compres- sive resistance, but there are a few cases in which it is larger than either, indicating an approach to the condition suggested in forming the equations already given. The strength of the alloys at the copper end of the series increases rapidly with the addition of tin, up to about 4 per cent. Transverse strength continues to increase up to about 1^/2 per cent, of tin; while the tensile and torsional resist- ances also increase, but very irregularly, to the same point. As this irregularity corresponds to the irregularity of the curve of specific gravities, it is probably due to porosity, and might not be seen in sound castings. STRENGTH OF BRONZES. 351 The maximum point of the three curves is reached at about the same point, viz., at the alloy containing 82.70 copper, 17.34 tin. From the point of maximum strength, the three curves drop rapidly to alloys containing about 27.5 per cent, of tin, and then more slowly to 37.5 per cent., at which point nearly the minimum strength is reached. The compression curve reaches its maximum between these points. The alloys of minimum strength are found from 3.75 per cent, tin to 52.5 per cent. tin. The absolute minimum is probably about 45 per cent, of tin. From 52.5 per cent, of tin to about 77.5 per cent, tin there is a slow and irregular increase in strength to the point which has been called the second maximum. From 77.5, per cent, tin to the end of the series, or all tin, the strengths slowly and somewhat irregularly decrease, the second minimum being reached at the end of the curve. All alloys containing more than 25 per cent, tin are prac- tically worthless for all purposes demanding strength, the average strength of these alloys being only about one-sixth of the average of those containing less than 25 per cent, of tin. Maximum strength is associated with a peculiar color, a reddish or pinkish gray, which marks the change from the ductile to the brittle alloys, and occurs between the percent- ages of tin which give a silver-white alloy in which no trace of copper could be detected by the eye, and the reddish- yellow to yellowish-gray alloys like No. 6 (lower end of bar) and No. 33. The results of these tests do not seem to corroborate the theory that peculiar properties are possessed by the alloys which are compounded of simple multiples of their atomic weights or chemical equivalents, and that these properties are lost as the compositions vary more or less from this definite constitution. It does appear that a certain percentage composition gives a maximum strength and another certain percentage a minimum, but neither of these compositions is represented by simple multiples of the atomic weights. There appears to be a perfectly regular law of decrease 352 MATERIALS OF ENGINEERING NON-FERROUS METALS. STRENGTH OF BKCNZES. 353 from the maximum to minimum strength which does no? have any relation to the atomic proportions. 211. Total Resilience, or the product of the mean resist- ance into the distance through which the resistance acts, is the work done in breaking a piece of metal. For tensile stress, it is equal to the mean resistance multiplied by the total elongation ; for transverse stress it is the mean resistance multiplied by the total deflection, and for torsional stress it is the mean resistance of the specimen as measured by the mean ordinate of the autographic strain diagram, expressed in foot- pounds of torsional moment, or pounds acting at the radius of one foot multiplied by the distance through which this moment is exerted as measured by the total abscissa of the diagram, and reduced to feet traversed by the resistance. Its values are given elsewhere. The total resilience under transverse stress was calculated from the curves of deflections by transverse stress, the area of the curve being directly proportional to the resilience, the ordinates representing resistances and the abscissas deflec- tions. The results are reduced to foot-pounds of work. In the cases of bars which bent to a deflection of more than 3^ inches (8.9 cm.) without breaking, the resilience within that limit of deflection was taken. The torsional resilience was calculated from the area of the autographic strain-diagram and reduced to foot-pounds of work. The resilience under tensile stress was not determined. Referring to the plates of curves of resistances, it will be found that resilience bears a very close relation to ductility, the curves being nearly similar, except in those por- tions of the curves representing the alloys which bent with- out breaking under transverse stress, and of which the trans- verse resilience is taken only within a deflection of 3^ inches. The maximum torsion resilience is given by No. 3 (96.06 copper, 3.76 tin), one of the most ductile of the strong alloys. No. 33 (88.40 copper, 11.59 tm ) gave maximum transverse re- silience within the deflection of 3^ inches, being the strong- 23 354 MATERIALS OF ENGINEERING NON-FERROUS METALS, est alloy which reached that deflection without breaking, but its total resilience is less than those of the more ductile bars, v/hich bent, without breaking, to deflections of more than 8 inches. From the bar which gave maximum total resilience a rapid decrease occurs to No. 8 (76.64 copper, 23.24 tin). From No. 8 to No. 20 (35.85 copper, 73.80 tin) all bars, with one excep- tion, show total resiliences so small, compared with the maxi- mum, that the curve of resilience between these points ap- proaches the bottom line of the plate so closely that it apparently coincides with it. The figures for transverse re- silience agree with those of torsional resilience between these points. From No. 20 to No. 28 (0.32 copper, 99.46 tin) there is a gradual increase of the total resiliences to the (t second maximum." The alloys which are of most value to the engineer are evidently those containing less than 20 per cent, tin, and, for the great majority of purposes, gun-bronze (copper 89.90) and the alloys containing rather less tin are likely to prove best ; while those containing from 10 to 15 per cent, tin are evi- dently to be chosen where hardness, combined with strength, must be secured. Alloys of these metals containing from 30 to 70 per cent, of either are rigid, brittle, and valueless for the ordinary purposes of the engineer, although some of them may have use for special work. The phenomenon of decrease of set with time was observed for the first time with No. 47. On relieving the bar of all pressure except that due its own weight, and except a very slight pressure (a few ounces) to insure that the pressure-block actually touched the bar and was not raised from it, the scale- beam balanced at 5 pounds, and the reading of the set was made. While reading the set the scale-beam was observed to rise, indicating increase of resistance to deflection, as it had similarly been observed to drop when resistance to stress took place. A number of observations of this increase of resist- ance to the permanent deflection were made, and also of the decrease of set, as measured by running back the pressure- S TKENG TH OF BRONZES. screw till the scale-beam again balanced at 5 pounds, and taking additional readings. The result of these observations showed that in one observation of 39 minutes the resistance of the bar, as measured by the scale-beam, increased 18 pounds^ and that in 2 hours 20 minutes the set decreased the amount of 0.0239 inch. This fact of the decrease of set with time has since been confirmed by a large number of tests made on the same ma- chine, and it has also been observed by other experimenters. It indicates that what has been hitherto called the "perma- nent set " of metals is in reality not entirely permanent, but is partially, at least, temporary, a fact already well-known. 212. Specific Gravity. The curve of specific gravities (Fig. 13) shows considerable regularity, indicating that the densities of the alloys follow a definite law. The alloys containing less than 25 per cent, of tin show irregular variation in specific gravity due to porosity. The figures obtained are the densities of castings, and not of the metals themselves, as they might be determined in fine pow- der, or from metal free from cavities. The densities of the castings are, hence, much lov/er than that of alloys given by other authorities, and for this reason the density of No. 6 A (87.15 copper, 12.69 tin) i n the shape of fine turnings gave the figure 8.943, and turnings of ingot- copper gave the figure 8.874. The strength and density are in a certain degree depend- ent upon each other, and the greater the density of an alloy of any given composition the greater the strength. This has been shown in experiments on gun-metal, which uniformly exhibits an increase of strength with increase of density. The casting of small bars, such as have been used in the experiments described, is especially unfavorable to the pro- duction of metal of great density, while in the casting of guns and other large masses the pressure of molten metal is much greater, and all conditions favor the increase of density and of strength. It is probable that the actual specific gravities of all alloys containing less than 25 per cent, tin do not greatly vary from 356 MATERIALS OF ENGINEERING N OX-FERROUS METALS. 8.95, and that the specific gravities of castings of these alloys will be less than 8.95 as they exhibit porosity. The specific gravity of an alloy is increased by repeated working. In determining the specific gravities, the pieces were first washed in alcohol to free them from any dirt or grease which might be attached to them, and then thoroughly dried. Before weighing in water, the pieces were boiled for two or three hours, to remove, as far as possible, the air inclosed in the pores of the metal, and after cooling in the dish in which they were boiled, they were placed under the receiver of an air-pump, and the air was further exhausted. They were then quickly transferred to distilled water, in which they were weighed, suspended by a loop of fine platinum wire from the arm of the balance. The water in which they were weighed was kept at the same level, and the proper correc- tion made for weight of the platinum wire. The results given are corrected for temperature of the water, being reduced to the standard of water of maximum density (39.4 Fahr., 4.! cent.). If the formation of the gas which causes blow-holes can be prevented, or if it can be removed from the metal while the latter is still in a fluid state, it is evident that the cast metal will be entirely free from them, and a metal of great density and strength will be obtained. No means has yet been discovered by which this desirable result may completely be accomplished, but it is not improb- able that it may be done by treatment of the fluid metal, or by the use of fluxes. The subject offers a fruitful field for experiment, one which it was proposed to explore, after con- cluding the researches on copper-tin, copper-zinc, and triple alloys, but one which was not carried out by the U. S. Board. The specific gravity of an alloy is increased by repeated tempering and rolling. The specific gravity of pure copper, according to authori- ties quoted in "Constants of Nature" varies from 8.360 to 8.958, electrolytic, hammered, rolled, or pressed copper giv- ing the highest figures and those which are probably the most nearly correct. STRENGTH OF BRONZES. 357 358 MATERIALS OF ENGINEERING NON-FERROUS METALS. The specific gravity of all alloys containing between 25 and 38 per cent, tin, which alloys are compact and homogeneous, is greater than 8.9 (reaching 8.97 at the latter percentage). The specific gravities given in the tables, as determined from the castings, show the cause of imperfections in strength and other qualities, and indicate that one proper method of improving strength is to increase density. They indicate that the lower the specific gravity of alloys which show a certain definite strength, the greater increase may probably be ex- pected from any cause which brings the specific gravity up to 8.95. Rolling, hammering, or compressing porous and ductile metals increases density. Casting under pressure has the same effect. It is probable also that temperature of pouring and rate of cooling have an influence upon density, and the use of fluxes which may remove occluded gases from the molten metals will increase it also. The maximum density of the series is given by alloy No. 12 (62.31 copper, 37.35 tin, by analysis), the original mixture of which corresponds to the formula SnCu s , and is nearly ap- proached by alloy No. 38 (62.42 copper, 37.48 tin). The fig- ures are 8.970 and 8.956 respectively. The former is higher than is given by any authority known to the Author for any alloy of copp.er and tin. From alloy No. 12 to the end of the series, to pure tin, an almost perfectly regular decrease of specific gravity occurs, that of tin being 7.29. From the regularity of this decrease of specific gravity it would seem that these alloys are but little subject to porosity in castings. In these alloys the density has no definite relation to strength. 213. Apparent Limit of Elasticity. The apparent limit of elasticity has been defined as the point at which distortion begins to increase in a greater ratio than the force which causes that distortion. In the curves of deflections and elonga- tions, and in the autographic diagrams of torsional stress, it is the point at which the curve begins (usually suddenly) to change its direction and to deflect toward the horizontal. The figure giving curves in which comparison is made of STRENGTH OF BRONZES. 359 the transverse, torsional, and tensile resistance, also contains curves showing the limit of elasticity under each of the three kinds of tests. In the general summary of results (Table LXV.) the elastic limits are represented by parts of the total re- sistance. It will be seen that the curves of limits of elasticity ob- tained from the three kinds of tests, coincide with the curves of resistance in the middle portion of the series, that contain- ing the brittle alloys, and fall beneath them at the ends, the figures in the summary showing the elastic limit to be there 100 per cent, of the total strength, and that of the more ductile alloys to be in some cases as small as 20 per cent, of the total strength, and to increase with the decrease of. ductility. In general, the ratio obtained by tensile test is higher than that obtained by either transverse or torsional test. In the stronger alloys, the elastic limit under tensile stress is reached at from 50 to 68 per cent, of the breaking load, and under transverse and torsional stress at 35 to 45 per cent. As the percentage of tin is increased beyond 17.5 per cent., the ratio of elastic limit to ultimate strength is increased ; alloy No. 8 (76.64 copper, 23.24 tin) giving a ratio of 100 per cent. ; the elastic limit was not reached till fracture took place. The same result is given by all alloys from No. 8 to No. 21 (38.37 copper, 61.32 tin). From No. 21 to pure tin, this elastic limit is reached before fracture, by both transverse and torsional tests. In both tensile tests of alloys containing between 62.5 and 82.5 per cent, of tin the elastic limit was either not reached or only just reached before fracture took place. In these alloys, the ratios of elastic limit to ultimate strength appear much higher in torsional than transverse stress. The ductile alloys, containing large percentages of tin, give ratios under torsional stress which gradually decrease as the per- cerftage of tin increases, the decrease being nearly regular from 98.5 per cent, to 45.3 per cent., between the alloy of 27.5 copper, 72.5 tin, and pure tin. In transverse test, the ratio is much more nearly constant, varying somewhat irregularly between the same compositions from 43.8 to 27.3 per cent. 360 MATERIALS OF ENGINEERING NON-FERROUS METALS, STRENGTH OF BRONZES. 361 214. Moduli of Elasticity. The moduli of elasticity were calculated from deflections observed in transverse test. The figures given are considered to be the most probable moduli of each bar within the elastic limit where the deflections arc proportional to the applied loads. The figures and the curve show irregularity, but not greater than should be expected from metals of different compositions. In alloys containing less than 24 per cent, of tin (all the stronger and more valuable alloys) the modulus of elasticity by transverse stress is about 14,000,000 (984,200 kilogs. per sq. cm.). From 25 per cent, to 35 per cent, tin, the modulus is some- what greater. From 35 to 75 per cent, there is a very great irregularity, corresponding to the irregularity in strength and other properties as shown by test, and much greater than any other property. From alloys containing 70 per cent, tin, to pure tin, the moduli become a little more regular, the tendency being to decrease as the tin increases. The modulus of these alloys averages a little more than half that of the stronger alloys con- taining less than 20 per cent, of tin. 215. Ductility is exhibited on the next set of curves. Figure 14. The copper-tin alloys are ductile in all directions when they contain principally tin or are nearly all copper, As the proportions alter and become more nearly equal, the ductility decreases, as the range between 25 and 75 per cent, tin is approached from either side, and within that range are very brittle. The alloys rich in copper are strong, though ductile, while those rich in tin partake of the properties of that metal. The method of variation of ductility is the same for all methods of test, but the test by transverse loading of bars gives greater opportunity for nice measurement and ex- hibits better the gradual introduction of this element as the lessening percentage of tin passes the figure 35 (copper, 65). Alloys containing less than 20 per cent, tin or more than 85 per cent, gain in ductility rapidly as change of composition goes on. Ductility is thus variable, quite smoothly and regularly MATERIALS OF ENGINEERING NON-FERROUS METAL& STRENGTH OF BRONZES. 363 with the composition of the alloy. In tension, ductility was measured directly, except in the case of the most brittle alloys, where it was too small to be measured. In transverse tests it was easy to obtain its measure by noting the deflection, which, in some cases, was greater than can be shown on the scale ; some bars, In fact, could not be broken by bending under the load. The autographic strain-diagram probably gives the best means of comparison. The maximum angle of torsion is 556.75 degrees, corresponding to an extension of the most extended fibre, originally parallel to the axis, of 2.2, nearly; the minimum, 0.4 degree, corresponds to an extension of but 0.000.006 ; pure tin gives a value 200,000 times greater than the most brittle alloy. Bars containing less than 12.5 per cent, tin did not break by bending to a deflection of 16 per cent, their length and 3j4 times their depth. The illus- trations given in the frontispiece exhibit the fracture of a number of these alloys, and present to the eye the characteris- tics of each, showing well the ductility or the brittleness, the toughness or the crystalline or granular surfaces revealed by breaking them. 216. Conductivity for heat and electricity varies in the copper-tin alloys as seen in Figure 15, which represents the data furnished by Calvert and Johnson, and by Matthiessen. There is seen to be a general correspondence, with a sudden break at the composition, copper 60 to 70, which appears in the curve for heat-conductivity, but not in that for electric conductivity. In both cases, this property remains practically constant for all alloys between copper o and copper 60, and rapidly improves as the alloy becomes more nearly pure cop- per. The standard taken for comparison is pure silver. The curves well illustrate the importance of securing purity in copper intended to be used as a conductor. 217. The other Physical Properties of the copper-tin alloys, as determined by various authorities, are exhibited in Figure 16. Mallet gives data relating to ductility, mallea- bility, hardness, and fusibility, on which are based several of these curves. With this curve of hardness is compared that of Calvert and Johnson, which corresponds, roughly, with it MATERIALS OF ENGINEERING NON-FERROUS METALS STRENGTH OF BRONZES. 365 so far as it goes. Hardness is here seen to increase steadily from pure copper to copper 75, at which point that of mini- mum ductility is reached. From this point it decreases stead- ily and with tolerable uniformity to the opposite end of the series. Malleability takes an almost precisely opposite course, falling to zero at copper 60-65 and rising again to the end (pure tin). Fusibility constantly lessens, as tin is added to copper, from end to end of the whole range. The curve of ductility closely follows that of malleability in alloys rich in copper, but the lack of cohesion of tin causes a great falling off at the opposite end of the line* CHAPTER X. STRENGTH OF BRASSES AND OTHER COPPER-ZINC ALLOYS. 218. The Brasses include all the copper-zinc alloys con- taining one-half copper and upwards, and a few special alloys are also given the name, as are copper-tin-zinc alloys, of which the tin forms but a small proportion. The name bronze has been applied, occasionally, to these ternary alloys, also. The terms bronze and brass are used indifferently by the older writers, but the tendency to restrict each term to a binary alloy, or to a ternary alloy in which one constituent exists in very small proportion, is decidedly observable among later writers and they will be so used in this treatise. In the cases of the brasses, as in that of the bronzes, no systematic investigation of the properties useful to the engi- neer had been made except by the U. S. Government. The U. S. Board, to which allusion has been already frequently made, authorized a determination of " the mechanical proper- ties and of the physical and chemical relations of alloys of copper, tin, and zinc," under the arrangement of committees approved by the Board, which assigned to the Committee on Alloys the duty of " assuming charge of a series of experi- ments on the characteristics of alloys and an investigation of the laws of combination." This research was conducted in the Mechanical Labora- tory of the Department of Engineering of the Stevens Insti- tute of Technology under the direction of the Author. The facts and data thus discovered and placed on record * will be summarized in this chapter after reference to earlier work on nearly related alloys. * Report of U. S. Board, Vol. II. ; Ex. Doc. 23 ; 46th Congress, 2nd Ses- sion. Washington : Government Printing Office, 1881. STRENGTH OF BRASSES. 367 219. Earlier Experiments. Mallet * found the tenacity of an alloy of copper, 90.7, zinc, 9.3, to be 27,000 pounds to the square inch (1,456 kilogs. per sq. cm.), with a specific gravity of 8.6 ; with 3 per cent, more zinc the strength was increased to very nearly 30,000 pounds (2,109 kilogs.). Copper, 85.4, zinc, 14.6, had a tenacity of about 32,000 pounds (2,249.6 kilogs.), and with copper, 83, zinc, 17, the figure became 31,000 (2,179 kilogs.). The tenacities varied little throughout the range and down to copper, 2, zinc, I, which is a Muntz metal'. Equal parts copper and zinc exhibited a tenacity of 20,000 pounds per square inch (1,406 kilogs. per sq. cm.) in Mallet's experi- ments ; the Author has obtained, in some cases, 40,000(2,812 kilogs.). Alloys rapidly become weaker, passing this maxi- mum, as the proportion of zinc is increased, as will be seen later, passing, however, a second maximum at about copper, 10, zinc, 90, which gives figures one-third as great as the first maximum. Brass cartridge metal tested with copper and steel by Lt. Metcalfe at the Bridesburg Arsenal in samples trimmed out to a contracted section of one inch (2.54 cm.), ' minimum breadth, and 0.03 inch (0.076 cm.) thick gave results as fol- lows: TABLE LXVI. TENACITY AND ELONGATION OF CARTRIDGE METAL. LOAD. PURE COPPER. COMMERCIAL COPPER. BRASS. OPEN HEARTH STEEL. Lbs. Kilogs. Unannealed. Annealed. T II. ! 600 BOO I.OOO 1,100 1,200 I,3 1,400 J '|oo 1,000 1,700 i, 800 227 272 363 454 499 544 590 635 680 726 $ 0.021 0.040 0.078 0-155 0.005 0.020 0.063 o. 156 0.266 o.o->5 0.015 0.040 0.087 0.130 0.214 0.290 0.013 0.025 0.042 0.0*2 0.085 0.033 0.050 0.075 0.102 0.152 0.266 CO. 2 7 0.057 0.085 C.IIO 0.163 0.270 0.050 0.075 O.IOO 0.130 0.165 O.22O 0.350 0.0225 O.OJO 0.0425 0.060 0.0775 0.140 O;23O 0.005 0.0075 0.013 0.030 0.065 0.126 O.II7 0.157 0.217 0.322 * Phil. Mag., Vol. 21, 1842. 368 MATERIALS OF ENGINEERING NON-FERROUS METALS. As the test-pieces were of the " grooved " form the elonga- tions serve for comparison of these specimens, but have no absolute value. 220. Sterro-Metal, a brass which contains a little tin and iron, was tested by Baron de Rosthorn at Vienna, and gave the following results : * TABLE LXVIL TENACITY OF STERRO-METAL. MATERIAL. TENACITY. Lbs. per sq. in. Kilogs. per sq. cm. Sterro-metal ; Gun-bronze ; cast 60,480 76,160 85,120 40,320 4,252 5,354 5,9 8 4 2,834 forjzed cold-drawn cast This alloy contained copper, 55.04; zinc, 42.36 ; tin, 0.83 ; iron, 1.77. The proportion of zinc may vary from 38 to 42 per cent, without appreciably altering the value of the alloy. Tre specific gravity of this metal was 8.37 to 8.40 when forged or wire drawn; it has great elasticity, stretching 0.0017 without set, and costs 30 to 40 per cent, less than gun-bronze. It has been forged into guns, cold from the casting. The strength of sterro-metal containing one per cent, and more of tin will be given in the following chapter on ternary alloys of copper, tin and zinc. 221. The Moduli of Elasticity, E., of various alloys have been found, as below, to the nearest round numbers : Holley ; " Ordnance a.\\d Armor," p. 424. STRENGTH OF BRASSES. TABLE LXVIII. MODULI OF ELASTICITY OF BRASSES. 369 VALUI . OF E. METAL. Lbs. on sq. in. Kilogs. on sq. cm. AUTHORITY. REMARKS. Brass 9 ooo ooo 632,700 Tredgold. 1 1 tin 80 copper cast. 12,000,000 843,600 Wertheim. ) it 13 ooo ooo QI-J QOO Bauschinger C Rolled. As will be seen, presently, the value is very variable with ordinary cast alloys of copper and zinc, but should be toler- ably uniform with rolled and drawn materials. 222. Copper-Zinc Alloys, including the brasses, were studied by the Author, and the investigation was, as al- ready stated, conducted in a similar manner to that described in the discussion of the alloys of copper and tin.* The specimens were in the form of bars, and were cast in an iron mould square in section, and similar in dimensions to that used in making bronzes. The experiments were made upon these bars as cast under ordinary conditions as before. The effects of different methods of casting, of slow and rapid cooling, of compression, either of the fluid metal or after solidification, and of rolling, tempering and annealing, were to have been made the subject of a special research. Two series of 'these alloys were made and tested. The first series was composed of bars differing in composition by 5 per cent. The bars of the second series also differed in composition by 5 per cent., the first bar containing 2^/ 2 per cent, zinc, the last bar containing 97^2 per cent. The bars were first tested by transverse stress ; the two pieces remaining after each transverse test were turned to size and tested by tension, and the four pieces thus formed * This account is mainly abridged from the Report to the Committee on Alloys of the U. S. Board. 24 37O MATERIALS OF ENGINEERING NON-FERROUS METALS. were tested by torsion. Some tests were made by compres- sion. The turnings from the tension test-pieces were analyzed. The specific gravities were also determined. The total weight of each casting was 4.5 kilograms (9.92 pounds). 223. Compositions Tested. A following table (p. 371) gives the compositions of the bars according to the original mixtures, the compositions of two portions of each bar as subsequently determined by analysis, and the specific gravi- ties. Bar No. 16 was made by melting together the upper half of bar No. 17 (21.00 copper, 77.59 zinc) and the lower half of bar No. 15 (25.98 copper, 72.90 zinc). The mould was heated each time before pouring into it the molten metal, the temperature given to it being higher the larger the amount of copper in the alloy. In melting the metal for bars, No. 7 to No. 21 (35 per cent, zinc to pure zinc), inclusive, except No. 16, the copper was melted first and covered with a layer of charcoal. The zinc was melted in a separate crucible, and poured into the crucible containing the molten copper, through the layer of charcoal. The mixture was thoroughly stirred with a dry stick. Some volatilization of the zinc took place, the amount being greater at some times than at others ; but the causes of this variation were not determined. Bars No. I to No. 6 (5 to 30 per cent, zinc) were made by first melting the copper, and then adding the zinc in the solid state. The losses of zinc vary very irregularly, and in two cases, bars Nos. 18 and 20(85 an d 95 per cent, zinc), there ap- peared to have been a greater loss of copper than of zinc. The temperature of casting was then found by the formula in which P is the weight of the water, P the weight of metal poured, / the temperature of the water before, and t' after STRENGTH OF BRASSES. 37* pouring, and c the specific heat of the alloy. The specific heat was assumed to be the mean of the specific heats of the components. The following table gives the temperatures : TABLE LXIX. ALLOYS OF COPPER AND ZINC. Estimation of Temperatures of Casting. Composition by original mixture. Weight grammes. Temperatures, Fahrenheit, Degrees. Temperatures of casting. Degrees. A c sumed specific Remarks. i 1 u jj i i . 1 1 heat. ll 4) * U N 5 rj tb U, <-> i... 95 5 907 131.8 54 "4 60 0.09517 4454 24567 Second casting. 2.. 3-- e 10 '5 907 907 212.3 321.4 53 155 65 loo 0.09519 0.09521 3035 3120 i66 7 : 6 Poured thick. 4- So 20 907 447-3 58 172 114 0.09523 2600 1426.6 5-- 75 25 907 381.26 54 100 o 09525 2652 M55 -5 6.. 70 30 907 257-9 52 120 68 0.09527 2631 '443-8 7-- 65 35 907 259.9 56 120 64 0.09529 2464 1351.2 8.. 60 40 907 65 J 5 2 0.09531 2584 1417.7 g.. 55 45 907 182.6 61 109 48 0-09535 2610 ro.. 50 50 907 199-5 51 104 50 0.09535 2492 1366.5 ii.. 45 55 907 237-4 53 102 49 0-09537 2065 1129.7 12.. 40 60 907 223.3 61 112 0^9539 2284 1251.1 14.. 35 30 65 70 907 907 185.9 203.6 102 no 45 50 0.09541 0.09543 2403 2444 '317.3 1340.1 Second casting. 15-- 25 75 907 168.0 61 98 37 0.09545 2191 i*99-5 Second casting. 16 Not taken. 17.. 20 80 907 169.3 51 .85 34 0-09547 1094 1089.6 Second casting. 18.. 19.. 15 10 85 90 9"7 907 316.0 289.5 56 54 16 106 60 52 0.09549 0.09551 1812 '9*3-9 Second casting. 20.. 5 95 907 163.0 60 : 73-5 13- r 0-095-3 860 460.0 21. . 100 4535 597-3 5 70 20 0.09555 1660 904.1 224. External Appearance of the Bars. The surfaces of bars No. I to No. 8 (5 to 40 per cent, zinc, original mixture) had a similar color and appearance, being generally of a dark yellow color, inclined to copper-red toward the copper end of the series, and more or less oxidized. No. i (5 per cent, zinc, original mixture) was variegated in color, exhibiting iridescence in places, the prevailing tints bein^ red, yellow, brown, and green. No. 2 (10 per cent, zinc) was rough, blow- holes, ridges and depressions were found over the whole of the bar. The others, from No. I to No. 7 (5 to 35 per cent, zinc), were smooth. No. 8 (40 per cent, zinc) was iough, the rough- 37 2 MATERIALS OF ENGINEERING NON-FERROUS METALS. ness being caused by slight cavities or blow-holes of irregular shape, none of which were deep. These bars were soft enough to be cut with a saw, the freshly-cut surface varying from yellowish-red at No. I to light yellow at No. 5 to No. 7 (25 to 35 per cent, zinc), No. 8 (40 per cent, zinc) being red- dish-yellow. The hardness gradually increased with the in- crease of zinc. Nos. 9, 10, and n (45 to 55 per cent, zinc) had surfaces similar in color to the preceding, but darker, approaching brown, and in some places covered by a light gray scale. They were harder than Nos. I to 8, but could be cut in the lathe with a good tool. It was noted that Nos. 5, 6, and 7 had a light yellow color, while the bars on each side, contain- ing either less or more copper, were reddish-yellow. Nos. 12, 13, and 14 (60 to 70 per cent, zinc) had a yellow- ish outside surface, a very thin skin ; the metal itself when broken was nearly white. The yellowish skin contained more copper than the rest of the casting ; it sometimes was so soft that it could be cut or bent, while the inside of the bar was nearly as hard as glass ; this was not determined by analysis. This soft yellow coating found on white alloys of copper and zinc was described by Mr. F. H. Storer.* The colors of the fractured surfaces of Nos. 12, 13, and 14 were nearly white. They were too hard to cut in the lathe. The ground surface of No. 12 was brownish yellow. The ground surface of No. 13 had a yellow tint, that of No. 14 was nearly silver-white. This sudden change between No. n and No. 12 (from 55 to 60 per cent, of zinc) corresponds to that observed in the copper-tin alloys of 24 to 30 per cent, of tin. Between No. 14 and No. 15 another change occurs, the yellow skin seen in No. 14 being entirely wanting in No. 15 ; the color of the outside surface of the latter is a dull bluish- gray. The fractured surface of No. 15 is bluish-gray, but lighter than the outside. No. 15 is much softer than No. 14, and can be cut in the lathe, although with difficulty. " Memoirs of the American Academy," vol. viii., 1860, p. 54. STRENGTH OF BRASSES. 3/3 From No. 15 to No. 20 (75 to 95 per cent, zinc) the sur- faces are much alike, bluish-gray and nearly smooth, the color becoming lighter as the proportion of zinc increases. Hardness decreases with increase of zinc. No. 21, all zinc, is' softer than No. 20, and lighter in color. The fractured and freshly cut surfaces of all bars from No. 15 to No. 21 are bluish-gray. No. 20 and No. 21 only show a crystalline ap- pearance, the others were finely granular. We may divide the alloys of copper and zinc into three classes, each of which has a distinct color. The first class includes those containing less than 55 per cent, of zinc, and may be called the yellow class. These are also the useful metals. The second class includes those containing between 60 and 70 per cent, of zinc, which are nearly silver white and exceedingly brilliant and hard and brittle. These have a yellow skin. The third class includes all those having more than 75 per cent, of zinc, and are bluish-gray, much softer as well as stronger than the second class. The alloys containing between 55 and 60 per cent, zinc and those containing between 70 and 75 per cent, zinc, show regular gradations between the first and second, and second and third classes, respectively, the changes from one class to the other taking place gradually, but within narrow limits. 225. Fractures; Colors. The fractures of these alloys were examined by Prof. A. R. Leeds, who furnished the fol- lowing description of their color and structure : No. o (cast copper). Coarsely fibrous, and radiate from centre of surface of fracture. Color, dark red from superficial oxidation. Fibres, interrupted and dotted over with minute ridges with sharp lines of separation. No. I (96.07 copper, 3.79 zinc). Surface, confusedly vesic- ular and projecting between the vesicular cavities upward into sharp points. Color of centre, brilliant yellow-red, chang- ing to light red on sides of fracture. The latter portion was likewise radiate in character, approaching No. o. No. 2 (90.56 copper, 9.42 zinc). Fracture, closely resemb- lirg No. I, with vesicular surfaces inferior in size. Color, more nearly approaching yellow. 374 MATERIALS OF ENGINEERING NON-FERROUS METALS. No. 3 (89.80 copper, 10.06 zinc). Fracture, highly vesic- ular and extremely- jagged from the great number of minute projecting points. Light yellow in centre, and feebly reddish- yellow at sides of fracture. The latter portion was likewise radiate in character. No. 4 (81.91 copper, 17.99 zm c). Surface in character re- sembling No. 3, but less acutely jagged. Color, brass-yellow. No. 5 (76.65 copper, 23.08 zinc). Surface pitted over with minute rounded depressions, and ridged up into regular ele- vations, with a somewhat rough feeling to the touch. Color, full yellow. No. 6 (71.20 copper, 28.54 zinc). Resembling No. 5, but the elevations more prominent and more acute to the sense of touch. Color, dark yellow. No. 7 (66.27 copper, 33.50 zinc). Centre of surface of fracture largely vesicular, the surfaces of the vesicles being likewise covered with minute rounded depressions. Color, gold-yellow. No. 8 (60.90 copper, 38.65 zinc). Surface slightly rough and uneven, with a few smooth, rounded cavities. Color, somewhat orange-yellow, apparently having undergone a slight superficial oxidation. No. 9 (55.15 copper, 44.44 zinc). Extremely rough and uneven. Surface tarnished, of dull reddish-yellow color. One large rounded cavity coated with smooth surface of gold- yellow color. No. 10(49.66 copper, 50.14 zinc). Confusedly vesicular, with regular surface of demarkation between the depressions. Not homogeneous. Surface at centre, deep yellow, surrounded by the larger portion of a whitish-yellow alternating with reddish-yellow, and bounded at sides by a radiated border of a similar color. Splendent. No. ii (47.56 copper, 52.28 zinc). In character somewhat approaching No. 10, but the lines of demarkation between depressions less evident, and the projecting ridges less promi- nent. Color, reddish-white. Brilliant. No. 12 (41.30 copper, 58.12 zinc). Largely conchoidal surface of fracture, with few surfaces and those smooth. STRENGTH OF BRASSES. 375 Dull orange-yellow color. Splendent. (The color of this fracture was nearly silver-white when freshly broken, but changed to yellow by oxidation.) No. 13 (36.62 copper, 62.78 zinc). Character of surface same as No. 12. Color more silvery. Splendent. No. 14 (32.94 copper, 66.23 zinc). Conchoidal fracture, with surface covered with rounded depressions too minute to be separately visible to the naked eye. Color, bluish-white. Splendent. No. 15 (25.77 copper, 73.45 zinc). Minutely vesicular fracture, giving a slightly rough surface. Color, dull bluish- white. No. 17 (20.81 copper, 77.63 zinc). Similar in color and surface to No. 15, but radiate fibrous in structure. No. 1 8 (14^19 copper, 85.10 zinc). Closely resembling No. 17. Color, dull bluish-white. No. 19 (10.30 copper, 88.88 zinc). Surface in small, un- even ridges, dotted over with rounded depressions of brilliant silvery surface. General color of mass, dull bluish-white. No. 20 (4.35 copper, 94.59 zinc). Extremely jagged sur- face. Large vesicular depressions, with splendent silvery surface. Color of mass, bright bluish-white. Sides of fract- ure, crystalline radiate. .No. 21 (cast zinc). Large lamellar crystalline plates, with rough surfaces of fracture between the laminae. Structure of crystals also radiating from centre. Splendent. Bluish- white. The second series comprises twenty bars. They were tested, mixed, and cast in the same manner as those of the first series. The table (p. 378) gives the composition mixture of each bar, the composition by analysis, and specific gravity. 226. Temperatures of Casting. The following table contains the temperatures of casting : 3/6 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXX. ALLOYS OF COPPER AND ZINC. Temperatures of Casting. H TEMPERA COMPOSITION BV ORIGINAL MIXTURE. WEIGHTS, GRAMS. TEMPERATURES. FAHRENHEIT. (DEGREES.) X y E TURES OF CASTING. (DEGREES.) - 1 i ^ u REMARKS. U ' O C ctf N ^ | "rt '3 J 1 ASSUMED S Fahrenhei Centigrad Temperature not taken. ii 7-5 907 167.26 6 4 112 48 0.09518 2847.2 1564- Temperature not taken. s'l z 7-5 907 277.17 6 4 I 4 76 0.09522 2752.3 1511.3 77-5 22.5 907 482.59 68 1 88 120 0.09524 2558.7 1403-7 72-5 27.5 32.5 907 907 426.95 577-7 60 64 158 1 80 98 ir6 0.09526 0.09528 2343-9 2091 .8 1284.4 IJ 44-3 62!s 37-5 907 439-55 63 1 58 I0 5 0.09530 2411.911338.8 57-5 42.5 907 397-42 53 158 100 0.09532 2552-7 1400.4 52.5 47-5 907 339-05 60 142 82 0-09534 2444.3 1339-5 47-5 42-5 37-5 37-5 52.5 57-5 62.5 67.5 907 907 907 907 296-53 388.15 327.33 224.45 U 64 83 130 158 142 138 76 90 78 50 0.09536 0.09538 0.09540 0.09542 2568.2 2363-3 2407-9 2255.8 1409. 1295-1 I 2 35.4 Mixed well; poured hot. Considerable zinc vola- tilized ; poured thick. 27-5 72-5 907 221.19 66 112 46 0.09544 2088.7 1142.6 22.5 77.5 907 322.52 62 125 63 0.09546 1981-3 1082.9 T 7-5 82.5 907 278.40 59 I0 4 45 o.c 954 8 1639-7 893.1 I2 -5 87.5 907 165.18 68 95 2 7 0.09550 1647.7 897.6 7-5 92.5 907 197.87 55 92 37 0.09552 1867.9 1019.9 2.5 97.5 907 180.36 67 93 26 0.09554 1461.8 794-3 The cast-iron mould was heated before pouring bars Nos. 31 to 41 inclusive, but was cold for bars Nos. 21 to 30 inclu- sive ; when the molten metal had a high enough temperature given it, no difficulty was experienced by chilling. As will be seen later, the zinc used in the second series, although sold as of good commercial purity, contained one per cent. lead. 227. Analyses. The following table gives, at one view, all the quantities thus far referred to : STRENGTH OF BRASSES. 377 TABLE LXXI. ALLOYS OF COPPER AND ZINC. Analyses and Specific Gravities. First Series. ORIGINAL MIXTURE. ANALYSES. VARIATION OF COMPOSITION. MEAN . ANALYSES. - E > 3 \\ 9 b 13 S. K o B *| | 1 jj N U i N | N ! N u i i i A.... i B.... 2 A.... 2 B.... 95 95 90 9 5 5 10 IO 95.98 96.16 90.49 90.62 3.90 3 68 9.48 9.35 + 0.98 + 1.16 + 0.49 + 0.62 1. 10 -1.32 -0.52 -0.65 [96.07 3-79 9.42 ( 8.854 j 8.758 18. 7 88 [3.825 [8.773 3 A.... IB:::: 4 A.... 4 B.... 5 A.... 5 B.... 1 80 75 75 15 15 20 20 25 25 89.31 90.29 81.97 81.85 77.84 75-45 10.54 7-57 17.95 18.03 21.78 24-37 + 4.3: + 5-29 + i 97 + 185 + 2.84 + o 45 -4.69 -5-43 2.05 -1.97 0.63 sg.bo [81.91 [76.65 10. 06 17-99 23.08 j 8.643 1 8.669 i 8.603 1 8.593 j 8.539 (8.517 [3.598 [3.528 6 A.... 6 B.... /o 70 3 30 71.34 71 .06 28.55 28.52 + i 34 IJ;J| 71.20 28.54 1 8.458 1 8.429 } 8.444 7 A ... 7 B.... 8 A.... 8 B.... 65 60 55 55 35 35 40 4 45 45 67.24 65.29 62.68 59-19 59.13 51.16 32-49 34-51 36.91 40.39 4036 48.52 + 2.24 + 0.29 + 2.68 -0.81 + 4.13 -3-84 -2.51 -0.49 -3-09 +0.39 -4.64 +3-52 ; 66.27 60.94 55 *5 33.50 38.65 44-44 i 8.392 1 8.350 j 8.443 18-367 j 8.369 18.io6 [8.371 } 8.405 [8.283 10 A 10 B 50 50 50 5 52.21 47-" 47-48 52.79 + 2.21 -2.89 -2.52 + 2.79 j 49.66 50.14 (8.301 1 8.281 8.291 ii A ii B.... 12 A ... 12 B.... 45 45 40 40 55 i! 60 47-45 47.67 42.09 40.51 52.35 52.20 57-32 58.91 + 2.43 + 2.6 7 + 2.09 +0.51 -2.65 -2.80 -2.68 -1.09 [47-56 [41.30 52.28 58.12 8'.c6i ' 8.061 8.061 i^ A.... 13 B.... 35 35 65 65 36.52 36.72 63.20 62.36 + 1.52 + '..72 -i. 80 -2.64 36.62 62.78 7.988 7-959 !7-974 14 A.... SB:::: 30 30 70 70 34-71 67.84 64.62 + 1.17 +4.71 -2.16 -5-38 32.94 66.23 . 7.847 7-775 7.811 15 A.... 15 B.... 16 A.... 16 B.... 25 25 22.5 22.5 75 75 77-5 77-5 25-56 25.98 26.44 25.40 74.00 72.90 72.73 73.38 + 0.56 +0.08 + 3-94 + 2.90 - I.OO 2.10 -4-77 -4.12 25.77 [25-92 73-45 J 7-627 1 7-722 J7.694 l7-68 4 [/C8 7 17 A.... 17 B.... 20 20 80 80 21.00 20. 6l 77-59 + 1.00 + 0.61 -2.41 2.33 [20.81 77.63 j 7-500 1 7.336 [7.4^8 18 A.... 18 B.... 15 15 If 13.86 14.51 86! 03 84.16 -1.14 -o.49 + 1.03 -0.84 [14.19 85.10 (7.166 1 7.159 [7-163 19 A.... 19 B.... XO xo oo oo 10.41 XO.X9 89.02 88.74 + 0.41 + 0.19 0.98 1.26 [10.30 88.88 j 7.181 ( 7.325 [7.253 20 A.... 20 B.... 5 5 95 95 4-36 94.69 94.48 -0.67 -0.64 -0.31 0.52 [,.35 94-59 j 7-177 1 7.038 [7.108 21 A o IOO 7.140 J 21 B.... o 100 / *V (7-143 MATERIALS OF ENGINEERING NON-FERROUS METALS TABLE LXXL Continued. Second Series. ORIGINAL MIXTURE. ANALYSES. VARIATION OF COMPOSITION. MEAN ANALYSES. g Z u > K K H i c jj U U L) z i i a u .0 a g rt a C a 1 ! U w W &5 <5 N S N J U N U N 3: 22 A.... 22 B.... 97-5 97-5 2.5 2.5 97.98 97.68 i. 60 2^6 None.* None.* +0.48 + 0.18 0.90 -0-34 [97.83 1.88 j 8.786 8.796 [ 8.791 23 A 23 B.... 24 A.... 24 B ... 92.5 92.5 87.5 87.5 7-5 7-5 12.5 I2 -5 92.65 91.99 88.86 89.01 7.42 7.94 ii 06 10.88 Trace. Trace. 0.12 0.16 + 0.15 0.50 + 1.36 + 1.51 0.08 + 0.44 -1.44 -1.62 [92.32 [88.94 7.68 10.97 Trace j 0.14-j S.724 8.767 8.764 8.729 [ 8.746 } 8.747 25 A.... 25 B 82.5 82.5 17-5 ^S 82. 8^ 83.00 17.06 16.90 0.17 0.16 + 0-35 + 0.50 ~-44 0.60 [82.93 16.98 0.17-j 8.662 8.603 [ 8.633 26 A.... 26 B.... 27 A.... 276.... 77-5 77-5 72-5 72.5 22.5 22.5 27.5 27.5 79-13 75.65 75.13 71.27 20.77 24.12 24.51 28.42 0.06 S3 0.21 + 1-63 -1.85 + 2.63 -1.23 + 1.62 -2.99 + 0.92 [77-39 [73-20 22.45 26.47 O.IO J. o.ig-j 8.607 8.542 8.511 8.418 [ 8.574 [ 8.464 28 A... 28 B .... 67-5 67-5 32.5 32.5 70.65 68.82 29.16 30.95 O.ig 0.23 + 2> I 5 + 1.32 -3-34 -1-55 [69.74 30.06 0.21-j 8.401 8.366 [ 8.384 29 A.... 2d B . . . . 62.5 62.5 37-5 37-5 63-36 36.46 36.26 O.IO 0.12 + 0.86 + 1.02 - 1.04 -1.24 [63.44 36.36 O.II j 8.417 8.405 [ 8.4- 30 A.... 30 B 57-5 57-5 42.5 42.5 58.22 58.75 4L25 40.94 0.47 0-37 0.72 1.25 -ilsl [o8.49 41.10 0.42] 8.367 8.358 [ 8.363 31 A.... 31 B.... 52.5 52.5 47-5 47-5 55-02 54.69 44-57 44-99 0.40 0-34 2.52 2.19 -2.93 -2.51 [54.86 44.78 0-37J 8.322 8.280 [ 8.301 32 A.... 32 B.... 47-5 47-5 52.5 52.5 49. 5 48.85 50.71 50.93 0.32 0.26 1-55 -1.79 -1-57 [48.95 50.82 0.2 9 | 8.228 8.203 [ 8.216 S3 A.::: 33 B.... 34 A.... 34 B .... 42.5 42.5 37-5 37-5 57-5 57-5 62.5 62.5 43.68 43- of 38.25 38.46 55.89 56.55 61.18 60.92 0.41 0.3 + 0.62 i!i8 0.54 0.75 0.90 -1.61 -0.95 -1.32 -1.58 [43.36 [38.36 56.22 61.05 0. 3 8| o.6o-j 8.068 8.999 7.987 7.976 [ 8.034 [ 7-982 35 A.... 35 B.... 32.5 32.5 67- 67- 35.52 63.55 63.87 o'.66 0.66 + 3-33 + 3.02 -3-95 -3-63 [35.68 63 -7 1 o.66J 7-973 7-959 [ 7.966 36 A.... 36 B.... 27-5 27.5 72. 72. 28.78) 70.59 29.62 69.75 0-55 0.55 + 1.28 + 2.12 -1.91 -2-75 [29.20 70.17 0-55) 7.746 [ 7.766 37 A.... 37 B.... 22.5 22.5 77- 77- l\:ll 77.40 77.46 0.70 0.63 0-73 0.64 o. 10 -0.04 [21.82 77-43 0.67} 7-452 7-379 [ 7.4i6 38 A.... 38 B.... 17.5)82. 17.16 17.81 81.87 81.36 0.99 0.86 0.34 + 0.31 0.63 -1.14 [i7.49 81.62 o.93J 7-231 7.218 [ 7-225 39 A.... 39 B.... 12.5(87. 12.587. 11-75 12.48 87.19 86.14 o-99 1.22 -0.75 O.O2 -0.31 -1.36 [ 12.12 86.67 i.n-j 7-258 7.217 j- 7.238 40 A.... 40 B.... 7-5,92. 7-592- 7.19 7.21 92.34 91.79 0-54 1.02 -0.31 O.29 0.16 -0.71 [ 7-20 92.07 o. 7 8J 7-293 6.968 [ 7-131 41 A.... 41 B.... 2-5 97- 2-597- 2.63 2.26 96.20 96.65 1. 08 I. O2 + O.T5 0.24 -1.30 -0.85 [ 2.45 96.43 ,o 5 ] 7.177 6.982 [ 7.080 I 228. Results of Tests. The next table contains the data obtained by test, arranged in order of composition, beginning with copper and ending with zinc, and carefully classified. The figures are, in each case, averages derived from two or more tests each. * No. 22 A had 0.37 per cent, iron and 22 B 0.24 per cent. iron, others had no iron or only traces. The s 5 X 3 I S 8 n fc < o COMPRES- ION TESTS. STRENGTH OF BRASSES. Xt|opsBi3 jo snpipoi^ | : : : : : 379 (spanod-jooj) JO -joj jo 3[J3uy (umtmrem jo 'juso'asd) (spanod-jooj) (JU33 J3d) uotssaadiuoD jo ianoray (spunod) iptn sjenbs J3d ' JO 'JU3D J3d) UOIJD3S p3.mjDB.ij jo (}U3D CM-i vo o ON "- O M M ir> ro t^ O M ei M H o O O O O O ^*f p io 1-1 O >0 00 ro vovo Nco. 0>oo '3U3D J3d) VlUJJl 3IJSBI3 (spunod) uon (spanodi uoij -33S \TSUl3uQ - w I': ; : T : : : 3- "O^iOoro^- ti-oo txoo oo . - . \O M 10 lOOO ON O l^- HI M ro r^mroS Cl f^c^ vo O O * mN '. : : "i : : : 1 (spanod-iooj) ssqoui f-" jo uonosy -3p B UjqilM 3DU3)llS3^J j 3jmdna jo sninpoj^ : to? : : : S 5 J? 5S ft S}'2 5 : : Ir : : ^ " 5 ^ 5 J^rf 3j- AilAVHO DUID3JS NV3W 5 a ,j> zSS m M M m\o "o rxvo rooo ^-oo n * * m ON O N ^i- rx < 10 ri ON r^ N NO -*OO tx M O r. ts.oo S tx SNO NO 10 ui 10 * i-mm*"* oooooooooooooooooooooooooooooooooo ONO txM JONOM J0-0 ON O- ON ONOO OO 00 00 tx tx fx! S.NO NO NO N bftoi . 380 MATERIALS OF ENGINEERING. NON-FERROUS METALS. I (Spimod-JOOj) 30U3IIIS3-JI 6 oo o u-> CT.\O mo ONOO oo o m ovo cooo-^wovot-^ \o M oo w O in t^oo ro rj-vo t^ O\ LO "~vo M fT V ro ro ^ O VO o O O O H O O N ON ^co in (^ rsi on a ment. JO -ao} jo JO '1U33 'j3d) (spunod-^ooj) 5 N ""t-vo ^OOOOQOQQQOOOOOOOOiON t^.oo* oo" 'OrowrororoOC OOOOOOOOOOOooovOvO ** CO ^ t^*O ro -^- s rn w -^ r^\o vo OO T}- i Ot>-PHi\OCO MOOVO ON M 0*0 ""> -^-"O Ooo\o ^f o" t^oo" tC <5v -T ; inoo" oT -4 1 ci ON c> 6" c> c lOP^iMtx-OninVOMCNj -H TfOO OO rOVO IOCQ IT) OO IOOO lOt^OO^roCNM **O !>-*< fOO "^"^O H moo t^ u"> O Tf- h>. ^J-OO VO'O N rorOMCO rorot^sin C^VO *O IA rf *O ("*") t-x w -$- ^00 rOOO ON M (S OO ONOO NO CN ON CQP^K M 6 M 6 6 d d 6 6 6 6 o o o' 6 o 6 6 o o o o OvOwOOOOOOOOOOOOOOOf^ 1^00 ^ ^?| liftl a|| |1 1 H ? R ro cT tC rn cToo' t^ t^vcT -4-OO oo'vo" CM <*o c?\ N" ^vo 10 M rCvo ro t^ o . H MM -T*-On LO\O o \o NO t^. t-~ r~ t-st^oo oo oo oo ON ON o> ON IANO vo ONNO NOONONOO-^ot^ ^- M 00 NO ON in ro rn r^lNO NO CNN r> oo m -^ o^oo r^roM mn>n- r-oo oo oo oo ON ON ON ;^%^2 88 s S TRENG TH OF BRA SSES. 3 8 1 229. Conclusions from Tests. In the preceding table, the " breaking load " by transverse stress is that which either causes a deflection of 3^ inches (9 cm.), or breaks the bar within that limit. The limit of elasticity is not a definitely marked point in any cases in which brasses or bronzes are under test, and the quantity here given as a limit is to be taken as approximate only, and not as representing a fixed natural quantity. The moduli of elasticity were cakulated from a series of deflections and loads, and the highest of the series of values so obtained is usually recorded as probably most correct, errors of observation and accidental errors usu- ally operating to depress the value. Alloys containing less than 10 per cent, zinc were usually somewhat defective and spongy. Fluxing may be expected to give sound casting only when special care is taken, as cop- per has a great affinity for oxygen and absorbs air freely when the metal is fluid. Alloys containing less than 55 per cent, zinc are yellow, and have been classed as " useful alloys/' Those containing less than 40 per cent, are noticeably weaker than those con- taining from 40 to 55. The former are ductile and have either a fibrous or an earthy fracture ; the latter are, in some cases, of nearly or quite double their strength, with less duc- tility, and the fractures are granular and lustrous. The maxi- mum strength is found not far from the composition, copper, 60 ; zinc, 40. The white alloys (zinc, 40 to 50 ; copper, 60 to 50) are weak, brittle, vitreous, and useless for ordinary pur- poses of construction. The blue-gray alloys (zinc, 70 to 100) are granular or crystalline, stronger than the white, but weaker than the yellow alloys, and have considerable ductility. The range of valuable composition, which, in the copper-tin alloys or bronzes, extends over a variation of but 25 per cent., covers a range of 50 per cent, in the list of brasses. In both classes, a sudden and great variation of properties is observed at a certain point, and the maximum and minimum are not far apart in either the brasses or the bronzes. Alloy No. 4 (copper, 82 ; zinc, 18), a good casting, was so ductile that it could not be broken by bending, but was sawn 382 MATERIALS OF ENGINEERING NON-FERROUS METALS. apart after test. Some interesting experiments, exhibiting the effect of prolonged stress on the brasses, were made, which will be described fully later. Maximum tenacity was exhib- ited by alloys containing about 40 per cent, zinc (copper, 50), and attained nearly 55,000 pounds per square inch (nearly 3,867 kilogs. per sq. cm.). The highest resistance to trans- verse stress was exhibited by the alloy copper, 47.7, zinc, 52.3. The softer alloys tested by tension usually stretch not only from end to end of the reduced part of the test-piece, but also in the heads by which they were held in the testing machine. In the case of an alloy containing 39 per cent, zinc ; 61 copper, a peculiar irregularity of elongation during test was observed, and a similar phenomenon was noted in the deflection of the same alloy under transverse loads. Between 40 and 50 per cent, zinc, liquation was often observed to oc- cur to a serious extent. Tests conducted with the autographic recording machine were concordant with those made by tension, and the quality of the metal was exhibited fully by the strain-diagrams so ob- tained. An alloy containing 89.8 per cent, copper exhibited great strength combined with a ductility about equal to that of pure tin. An exterior fibre, originally parallel to the axis, was extended to 3^ times its original length. Alloys ap- proximating 90 per cent, copper had very great total resili- ence. Alloys containing copper, 40, zinc, 60, were extremely rigid, extending, in some cases, less than o.oi of one per cent., and even as little as 0.00006 of their original length. Alloys containing copper, 15, zinc, 85, were subject to serious loss of strength in consequence of the existence of minute pores in large numbers, which, while invisible oftentimes, may injure the casting more seriously than large blow-holes usually weaken alloys liable to them. When testing by compression, a reduction of 10 per cent, in the length of the ductile alloys was made the limit, but the loads causing a compression of 5 and of 20 per cent, and up- ward, were also reported, as below. One of the silver-white alloys was found to be the strongest, carrying a load exceed- ing 120,000 pounds per square inch (over 8,436 kilogs. on the sq. cm.). STRENGTH OF BRASSES. 383 230. Notes taken during Tests are given at some length in the report on this investigation. A few of the compo- sitions exhibit properties, as thus recorded, which may be given place here. In tension tests, in the first series, maximum average strength is given by bar No. 9 (55.15 copper, 44.44 zinc), 44,280 pounds per square inch (3,113 kilogs. per sq. cm.). An inspection of the table shows that this average re- sult is reduced by liquation in bars No. 8 and No. 9, as No. 8 B (59.19 copper, 40.39 zinc) and No. 9 A (59.13 copper, 40.36 zinc) have nearly the same composition by analysis ; and the strength of these pieces is much higher than the average of the two pieces of either No. 8 or No. 9, being 51,380 and 53,660 pounds per square inch (3,612 and 3,772 kilogs. per sq. cm.), respectively. This indicates that maxi- mum strength is possessed by an alloy containing less than 44 per cent. zinc. Transverse tests showed the maximum transverse resistance to be exhibited by bar No. n (47.56 copper, 52.28 zinc), but this is not confirmed by tests made subsequently by either tensile, transverse, or torsional stress. Bar No. 12 (41.30 copper, 58.12 zinc) confirmed the results obtained by the transverse test, showing an entirely different metal from the preceding. It was weak and brittle. The metal was so hard that the pieces could not be turned in the lathe, and were therefore tested in their original square sec- tions. No. 12 A broke at 4,324 and No. 12 B at 3,130 pounds per square inch (3,040 and 2,200 kilogs. per sq. cm.). No at- tempt was made to measure the elongations ; they were ex- tremely small. The fractures were precisely like that ob- tained by transverse stress. The minimum tenacity, 1,774 pounds per square inch (1,247 kilogs. per sq. cm.), was exhibited by bar No. 14 A (31.17 copper, 67.84 zinc), one piece only being tested. The aver- age tensile strength of No. 13 (36.62 copper, 62.78 zinc), which showed the lowest transverse strength, was but little higher, being 2,656 pounds (1,867 kilogs. per sq. cm.) The curves of strength of the first and second series show a generally close agreement, except in the highest part of two curves, which are not found to indicate ^.^w^t UW{ ^ CPTHE ^ UNIVERSITY OF 384 MATERIALS OF ENGINEERING NON-FERROUS METALS. of the bar of maximum strength. The curve of the second series probably is most nearly the true one. In the series of No. 29 (63.44 copper, 36.36 zinc), No. 29 A broke at 48,760, and No. 29 B at 46,840 pounds per square inch (3,437 and 3,293 kilogs. per sq. cm.), after elongations of 31 and 32.4 per cent., respectively. The fractures were of a light brownish-yellow color, and very compact and homo- geneous. The plane of fracture was inclined to the axis, as with most of the pieces, and the surfaces were slightly pol- ished. The pieces were uniformly ductile throughout their whole lengths, as was shown by the uniform decrease of di- ameter as the pieces elongated. In testing No. 29 A, a sudden dull sound was several times emitted from the piece, and at the same instant the resistance decreased, in one case, 1,300 pounds (600 kilogs., nearly). This may be due to interior molecular action, of the same nature as that which produced the crackling sound noted in some transverse tests, or the irregularity in the increase of deflections noted in others. No. 30 (58.49 copper, 41.10 zinc). The average strength of the two pieces of this bar was higher than that of the pre- ceding, and the highest of this series. No. 30 A broke at 52,260 and No. 30 B at 48,640 pounds per square inch (3,674 and 3,419 kilogs. per sq. cm.), after elongations of 10.18 and IO per cent., respectively, showing much less ductility than the preceding bars, with greater strength. There was observ- able irregularity in the increase of elongations under increase of load, which corresponds with the irregularity of deflection observed in the transverse test of the same bar. Heat was generated, in some cases of test by tension, suf- ficient to make it uncomfortable to hold the broken end of the test-piece in the hand. This was observed to be most noticeable in alloys containing rather less than 75 per cent, copper. While testing an alloy containing 63 per cent, cop- per, sudden depressions of resistance were occasionally ob- served accompanied by dull sounds probably due to internal molecular disruption. 231. The Tenacity of Brass may be roughly reckoned, when the proportion of copper exceeds one-half, as will be STRENGTH OF BRASSES. 385 seen on comparing the data obtained from good specimens of brass, as T = 30,000 + 500 2. 232. In Compression Tests, it proved that No. 5 (76.65 copper, 23.08 zinc) was much stronger than either of those richer in copper, requiring 42,000 pounds per square inch (2,953 kilogs. per sq. cm.) to cause a compression of 10 per cent. The elastic limit was apparently passed at about 26,000 pounds per square inch (1,448 kilogs. per sq. cm.). From this point the curve, after turning toward the horizontal, proceeds in a nearly straight line, but slightly convex to the axis of ab- scissas till a compression of 35 per cent, is reached, showing an increase of the ratio of load to compression, and indicating that the increase of diameter which is given by the compres- sion merely tends to increase the strength of the piece op- posing a greater sectional area to the stress. The piece, after 35 per cent, compression, was bent in the form of a double curve. On continuing the compression, the bending of the piece caused it to offer a slightly diminished resistance, a di- agonal crack appearing on one side, and the curve again shows a curvature concave to the axis of abscissas. On continuing the compression, after 140,000 pounds per square inch (9,842 kilogs. per sq. cm.) of original section had been applied, the compression amounting to 5 2.9 per cent., the resistance decreased to 110,000 pounds (7,733 kilogs.), probably in consequence of the weakening produced by the presence of the crack. The piece was then removed, the total compression being 57.5 per cent. The piece after removal measured only 0.87 inch in length, and two diameters at the middle of the specimen measured 1.03 inches and 0.91 inch, the section being approximately elljptical. The turned surface was slightly roughened by the com- pression. No. 8 (60.94 copper, 38.65 zinc) proved to be much stronger than No. 5, the load required to produce a compression of 10 per cent, being 75,000 pounds per square inch (4,956 kilogs. 25 386 MATERIALS OF ENGINEERING-NON-FERROUS METALS. per sq. cm.). The elastic limit was apparently reached at 30,000 pounds per square inch (2,109 kilogs. per sq. cm.), after a compression of 1.25 per cent. After passing the elastic limit, the resistance again became nearly proportional to the load, the ratio being much less than before. The piece be- came slightly bent and the surface somewhat roughened by the strain. After a compression of 24.8 per cent., the maxi- mum resistance to this compression being 99,000 pounds per square inch (7,000 kilogs. per sq. cm.), the resistance decreased in consequence of the bending of the specimen. When the piece was removed after a compression of 26.95 per cent, its diameter was found to have increased to about 0.73 inch. No. 9 (55.15 copper, 44.44 zinc) was somewhat stronger than No. 8, a compression of 10 per cent, being caused by 78,000 pounds per square inch, and breaking at 136,000(5,883 and 9,561 kilogs. per sq. cm.), after a compression of 22.6 per cent. The elastic limit apparently was reached at about 30,000 pounds per square inch (2,109 kilogs. per sq. cm.). At 136,898 pounds (9,625 kilogs.), after a compression of about 23 per cent., the piece suddenly gave way, a small piece shearing diagonally from the upper end. The piece had be- come slightly bent under the stress before rupture occurred, and this bending may partly account for the breaking, as, in consequence of the bending, the stress was brought upon one side of the upper surface and was not distributed evenly over the whole surface. The diameter of the piece was increased to about 0.71 inch. No. 10 (49.66 copper, 50.14 zinc) had a much greater re- sistance to a given deflection than No. 9, a compression of 10 per cent, being caused by 117,400 pounds per square inch (8,253 kilogs. per sq. cm.), and fracture occurring in precisely the same manner as that of No. 9 at 123,860 pounds (8,707 kilogs. per sq. cm.), after a compression of 11.25 P er cent. The elastic limit appears to have been reached at about 40,000 pounds (2,812 kilogs.), but the point is not clearly defined. The diameter was increased to about 0.71 inch before break- ing, being nearly uniform throughout the length. The surface was very slightly wrinkled by the compression. STRENGTH OF BRASSES. 387 No. II (47.56 copper, 52.28 zinc) was much stronger than any other of the series tested, breaking at 138,528 pounds per square inch after a compression of 13.6 per cent., a compres- sion of 10 per cent, being produced by 121,000 pounds (9,740 and 8,506 kilogs. per sq. cm.). The elastic limit was reached at about 35,000 pounds (2,460 kilogs.). The behavior of this piece before fracture was almost exactly like that of No. 10, as is shown by the close agreement of their curves. The fracture took place by shearing diagonally across the speci- men just above the middle. The diameter was increased by the compression to about 0.67 inch. No. 15 (25.56 copper, 74.00 zinc) exhibited a behavior under compression very different from that of the piece pre- viously tested. It broke at 1 10,822 pounds per square inch (7,791 kilogs. per sq. cm.), after a compression of 5.85 per cent. An elastic limit was apparently reached at about 80,000 pounds per square inch (5,624 kilogs. per sq. cm.), the ratio of com- pression to load after this point being very much greater than it was before this load was reached, as is plainly shown by the curve. After 110,822 pounds (7,791 kilogs.) had been reached, the compression being 4.8 per cent., the resistance decreased to 107,562 pounds (7,563 kilogs. per. sq. cm.), as the compression increased 105.85 per cent., and the piece then suddenly broke, the upper half flying into several fragments, a wedge-shaped piece being apparently formed at the top which seemed to split open the lower portion. The diameter was increased to 0.635 inch by the compression, as measured after breaking, on the lower part of the specimen. 233. In Transverse Tests, which were the first in order, an examination of the cast bars of the first series showed bars Nos. i, 2, and 3 (3.79 to 10.09 zinc) to be defective, and the results are not considered conclusive as to the properties of the metal. These bars were soft and spongy, and, in places, showed signs of oxidation. It appears probable that the de- fective structure of these bars is due to the method of cast- ing, which was not suitable for these compositions, and is probably not necessarily an inherent defect of metals of these compositions properly cast. In the second series the same 388 MATERIALS OF ENGINEERING NON-FERROUS METALS. peculiarity was observed in the transverse tests of alloys con- taining small proportions of zinc (less than 12.5 per cent.) with one exception, a bar containing 7.5 per cent. This indicates that it may be quite possible to secure good castings of alloys containing small percentages of zinc, provided the proper conditions are discovered and observed. The causes of the formation of blow-holes and of oxida- tion have not been determined. It would seem that the strength of sound castings of these metals should approach that of those having higher percentages of zinc. The curve is, therefore, continued in a straight line from pure copper to No. 4 (81.99 copper, 17.99 zinc). All alloys of copper and zinc containing less than 55 per cent, of zinc, may be considered as included in the first class, or useful alloys, which are all distinguished by a yellow color. The forms of the curves of strength indicate that the first class of alloys might be divided into two divisions, one show- ing considerably greater strength than the other. The first division includes those from No. 4 to No. 7 (17.99 t 33- 50 zinc) inclusive, with also, probably, Nos. I, 2, and 3, or all the alloys from pure copper to those containing 33.50 zinc. These show a modulus of rupture from 21,000 to 28,000 (1,476 to 1,968 kilogs. per sq. cm.), increasing slightly with the per- centage of zinc. They are also characterized by great duc- tility and fibrous or earthy fracture. The second division in- cludes bars No. 8 to No. II, inclusive (38.65 to 52.28 zinc), which show much greater strength than the preceding, the modulus of rupture of No. 8 being 38,968, and that of No. II 48,471 (2,740 and 3,407 kilogs. per sq. cm.), and less ductility. The fractured surfaces of No. 8 and No. 9 (60.94 copper, 38.65 zinc, and 55.15 copper, 44.44 zinc) resemble in appearance those of No. 7 (66.27 copper, 33.50 zinc), being earthy or fibrous, but having a darker color. The fractures of No. 10 and No. 11 (49.66 copper, 50.14 zinc, and 47.56 copper, 52.28 zinc) are very different from those of bars containing less zinc, having a granular structure and lustrous surface of fracture. The modulus of rupture of No. 10 is much less than that of STRENG TH OF BRA SSES. 3 89 the other three bars of this portion of the series, Nos. 8, 9, and 11, but this is probably exceptional, as the fracture indicates defective structure. No II (47.56 copper, 52.28 zinc) gave the highest modulus of rupture of the series, 48,471 pounds (3,407 kilogs.), and this would indicate the maximum strength of the series ; but this result is not confirmed by other tests of the same bar, nor by any of the tests of the second series. These all indicate that the point of maximum strength lies between No. 8 and No. 9 (38.65 and 44.44 zinc). The moduli of rupture of Nos. 8, 9 and 10, although much higher than those of the bars contain- ing less zinc, are lower than those of nearly similar composi- tion in the second series, but the reason of this is not ap- parent. Between bar No. 11 (47.56 copper, 52.28 zinc) and bar No. 12 (41.30 copper, 58.12 zinc) there is a sudden change of prop- erties. Nos. 12, 13, and 14 (58.12 to 66.23 zinc) represent the second class of the copper-zinc alloys-, which, as noted in describing the external appearance of the bars, is distinguished by a nearly white color, vitreous fracture, and very brilliant lustre, and also by great weakness and lack of ductility. They correspond closely in all their properties to the silver-white alloys of copper and tin. The minimum strength is given by bar No. 13 (36.62 copper, 62.78 zinc), its modulus of rupture being only about one-tenth of that of the maximum, bar No. ii (47.56 copper, 52.28 zinc), which differs from it in compo- sition only about 20 per cent. Bar No. 15 (25.77 copper, 73.45 zinc) shows a very much greater strength than No. 14, and marks the boundary of the third class, which includes all the bars containing more than 73.43 per cent, of zinc. This class is distinguished by a blu- ish-gray color, and finely granular structure, which becomes crystalline as the composition approaches pure zinc, and a much greater strength than the second class, although not so great as the first class, the yellow and useful metals. There is a somewhat irregular increase of strength from No. 15 to No. 19 (73.45 to 88.88 zinc). The latter represents the point of " second maximum " strength in the series, which 3QO MATERIALS OF ENGINEERING ^ 7 ON-FERR O US METALS. corresponds to the second maximum of the copper-tin alloys. From bar No. 19 there is a regular and rapid decrease of strength to pure zinc, which represents the " second minimum/' It will be noted that the curve of transverse strength of the copper-zinc alloys is not nearly as regular as that of the alloys of copper and tin ; but in many respects the two curves show a marked resemblance. The most striking contrast be- tween the two curves is the much greater range of composi- tion of the useful metals among the copper-zinc alloys, the curve of copper-tin alloys showing that the useful metals are all comprised within the limits of less than 25 per cent, of tin, while in the copper-zinc alloys the useful metals may contain as much as 52 per cent, of zinc. A sudden decrease of strength takes place at a definite point in both sets of al loys, and the curves are in this respect similar. The bars of minimum strength of both are also similar in their properties. The point of minimum strength is very near the point of maximum strength in both curves. That part of the curve which represents the third class of alloys of copper and zinc, corresponds with the curve of those copper-tin alloys which contain more than 50 per cent, of tin, and, like it, shows a second maximum; but it shows that the alloys containing a large amount of zinc have much greater strength than alloys containing a large amount of tin. The former are also much harder than the latter. The transverse tests of the second series indicate the same relations between strength, ductility, and composition that were noted in tests of the first series. From bars No. 22 to No. 28 (1.88 to 30.06 zinc), inclusive (excepting bars No. 22 and No. 24 as defective), there is a very gradual increase in the modulus of rupture. Bars No. 29 and No. 30 (36.36 and 41.10 zinc) show a rapid increase in strength over the preceding; the corresponding moduli of rupture are respectively 43,216 and 63,304 pounds (1,296 and 4,450 kilogs. per sq. cm.), the latter being the maximum modulus of rupture of the series. This maximum does not correspond with that of transverse tests of the first series, but is confirmed by all the other tests. STXENG TH OF BRA SSES. 39 1 234. Tests by Torsion confirm the results obtained and deductions made from the other experiments : From No. 4 to No. n (17.99 to 5 2 - 2 % P er cent, zinc) the average strength of all the pieces is quite high, the curve con- firming the curve of tensile results almost exactly, and indi- cating the character of the first class, or useful alloys. Between No. n and No. 12 (52.28 and 58.12 zinc) a very sudden decrease of strength takes place, and Nos. 12, 13, and 14 (58.12 to 66. 23 zinc) show very low torsional strength, these metals being in the second class, or silver-white and brittle alloys. From No. 15 (25.77 copper, 73.45 zinc) to the end of the series (pure zinc) the torsional tests indicate the characteris- tics of the third class, showing greater strength and ductility than the second class, the latter quality increasing toward pure zinc, and the strength reaching a maximum at No. 19 (10.30 copper, 85.10 zinc). No. II (47.56 copper, 52.28 zinc) gave a strain-diagram similar in form to that of soft cast iron or hard bronze, and very different from those obtained from alloys richer in cop- per. Of No. 12 (41.30 copper, 58.12 zinc) two pieces only were tested. The results correspond with those of tensile and transverse tests, showing that the metal is extremely weak and brittle. The fractures were silver-white, vitreous, and conchoidal. The pieces were too hard and brittle to be turned in the lathe, and were shaped by grinding with an emery wheel. The ductility is extremely slight, the exten- sion of a line of particles, one inch long in the surface parallel to the axis, being only 0.00006 inch. No. 130 (36.52 copper, 63.20 zinc) was, if possible, even weaker and more brittle than No. 12. Only one piece was tested and this was not brought to a cylindrical form, but was tested in its original square section. The strength was much less than that of any other piece of the series, showing the composition containing 63.20 zinc to be about that of minimum strength. The strain-diagram was a straight and nearly vertical line. Of No. 33 (43.36 copper, 56.22 zinc) two pieces only were tested. They were too hard to be turned 3Q 2 MATERIALS OF ENGINEERING NON-FERROUS METALS. in the lathe, and also were shaped by an emery wheel. The torsional moments, after being reduced to the equivalents of those of pieces of standard diameters, were much less than those of the preceding bars. The appearance of the fractures also showed as great a difference in the structure of the metal as was indicated by the difference in strength. Both fract- ures were diagonal, but No. 33 A was of a pinkish gray color and finely granular structure, and No. 33 B was of a brilliant silver-white color, smooth and vitreous. The analyses of the turnings of the tension pieces show that the difference was due to liquation ; No. 33 A containing 55.89 per cent, zinc, and No. 33 B 56.55 per cent, zinc. The fact that so small a difference in the percentage of zinc should make such a great difference in properties is evidence of the very rapid though continuous change which takes place on the boundary line between the first and second classes of the copper-zinc alloys, and which is plainly shown by the rapid fall of that portion of the curve corresponding to alloys of about this composi- tion. 235. Brass Shafts and spindles subjected to torsion may be calculated by the formula i^f/^JL % given in Chapter VIII., Art. 166, in which s varies from 5,000 to 60,000, according to composition and soundness of the alloy. If A^ is taken to measure the difference between the percen- tage of zinc present and that of maximum resistance, 45 per cent., a rough estimate may be taken, as s, = 50,000 - 333 A z when the alloy contains less zinc, and s\ 50,000 3,000 A z between z = 45 per cent, and z = 60 per cent. STRENGTH OF BRASSES. 393 In metric measures, s*m = 3,5^5 - 24 A*; s\ m = 3,515 - 211 A*. 236. The Records of Tests of a selected number of cop- per-zinc alloys are here given, and those of several others are presented later when considering the effect of prolonged stress on this class of materials. These records are extracted from the set presented to the U. S. Board and printed in the report of that body. Each record is accompanied by memo- randa relating to the conditions of test and details of the ex- periment which render further explanation unnecessary. TABLE LXXIII. TESTS BY TENSILE STRESS. Alloys of Copper and Zinc. Dimensions. Length = 5" ; diameter =0.798". BAR NO. 25 B. COMPOSITION. Original mixture : Cu, 82.5 ; Zn, 17.5. Analysis : Cu, 83.00 ; Zn, 16.90. K o 2o " \ ^ 2 fc 2 z CO o S * 0) .g Z M o w * K X r S SET. 1* Ij 9C V. - p s SET. ** W jg * < u < o 5 <^ < 3 3 H M 3 g K Z |aa H Pounds. Inch. Inch. 1 Pounds. /ffoi. Inch. 1,000 0.0014 0.03 17,000 0.3194 6-39 2,000 0.0037 . . 0.07 18,000 0.3600 7.20 4,000 0.0104 . 0.21 19,000 0.4034 . 8.07 200 o oo 7 .... 20,000 0.4460 8.92 6,000 7,000 0.0230 0.0326 0.46 0.65 200 2I,OOO 0.4892 o 4404 9'.78 8,000 200 9,000 10,000 11,000 12,000 200 0.0412 0.0500 0.0616 0.0840 0.1154 22 00 0.82 1. 00 1.23 1.68 2.31 22,000 23,000 24,000 32,800 Total el< LI/': Diametei 0.5274 Measuring a Broke 2 inch >ngation mea = 23.4 per cen of fractured 10.55 11.17 pparatus slipped, es from D end. sured after breaking, section. 0.608". 13,000 0.1483 2.97 Tenacity per square inch original section, 14,000 15,00-0 16,000 0.1883 0.2344 0.2747 3.76 4.69 5-49 ^2,800 pounds. Tenacity per square inch fractured section, 56,493 pounds. 2OO o 2676 394 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXIII. Continued. BAR NO. 26 B. COMPOSITION. Original mixture : Cu, 72.5 ; Zn, 27.5. Analysis: Cu, 75.65 ; Zn, 24.15. H ^ h a m g o K z Z o w ffi || l|, l s . | * . v. 5 5 SET. K (J P SET. |g| Q 3 og3 i" 3 a u Pounds. Inch. Inch. Pounds. Inch. Inch. 2,000 o 0040 O.o8 19,000 0.3326 6 6e 3,000 7 0.0062 0.12 20,000 0.3834 U.v.^ 7.67 4,000 O.OIOO 0.20 200 0-3724 5,000 0.0144 0.29 21,000 0-4334 8.67 6,000 0.0215 o. 43 22,OOO 0.4846 96O 7,000 0.0209 jj 0.60 23,000 0.5380 .uy 10.76 8,000 0.0368 0.74 24,000 0.5938 11.88 200 0.0221 200 0.5788 9,000 10,000 0-0443 o . 05 i 8 0.89 i .04 25,OOO 26,OOO 0.6480 0.71 s6 12.96 TA OT 11,000 I2,O~O 0.0646 0.0698 1.29 1.40 27,000 36,840 Measuring apparatus slipped. Broke 2 inches from B end. 200 0.0636 Total elongation measured after breaking, 13,000 14,000 0.0878 - XI 33 1.76 2.27 1.27" = 25.4 per cent. Diameter of fractured section, 0.587". 15,000 0.1513 3-03 Tenacity per square inch, original section, l6,OOO 200 0.1867 0.1784 3-73 36,840 pounds. Tenacity per square inch, fractured section, 17,000 0.2348 4.70 68,064 pounds. l8,OOO 0.2813 5-^3 BAR NO. 2Q B. COMPOSITION. Original mixture: Cu, 62.5 ; Zn, 37.5. Analysis : Cu, 63.52 ; Zn, 36.26. 1,000 O.OOII O.O2 25,000 o. 2097 4.19 2,000 0.0034 0.07 26,000 0.2371 4-74 3,ooo 0.0055 O.II 27,000 0.2668 5-34 4,000 0.0078 O.l6 28,OOO 0.2961 5.92 5,000 0.0100 0.20 ; 200 0.2784 6,000 O.OI2I 0.24 29,000 0.3287 6^57 7,000 0.0142 0.28 30,000 0.3665 7-33 8,000 0.0166 0-33 3I,OOO 0.3988 7.98 9,000 0.0191 0.38 32,000 0.4260 8.52 10,000 0.0218 0.44 200 0.4252 11,000 0.0257 0.51 33,000 0.4790 9-58 12,000 0.0293 0-59 34,000 0.5173 Jo. 35 200 0.0075 35ioo o.55 8 5 11.17 13,000 0.0336 0.67 36,000 o . 6090 12 18 14,000 0.0392 0.78 200 o'. 5 886 15,000 16,000 200 0.0452 0.0520 0.0322 0.90 1.04 37,000 , Measunr 47,840 o . 6548 g apparatus s Broke i inch lipped, from B end. 13.10 17,000 18,000 19,000 0.0643 0.0678 O.o3l2 :::::: 1.29 *-35 1.62 Total elongation measured after breaking. 1.62" = 32.4 per cent. Diameter of fractured section, 0.656". 20,000 200 0.1061 0.0814 2.12 The piece drew down very uniformly through the whole length to a diameter of about 21,000 0.1142 2^28 0.685". 22,000 0.1350 2.70 Tenacity per square inch, original section, 23,000 0.1571 3-14 47,840 pounds. 24,000 0.1836 3-67 Tenacity per square inch, fractured section, 200 0.1683 70,772 pounds. STRENG TH OF BRA SSES. 395 TABLE LXXIII. Continued. BAR NO. 4 A. COMPOSITION. Original mixture : Cu, 80; Zn, 20. Analysis : Cu, 81.97 ; Zn, 17.95. LOAD PER SQUARE INCH. ELONGATION IN 5 INCHES. SET. [ill LOAD PER SQUARE INCH. ELONGATION IN 5 INCHES. SET. iii Pounds. 1,600 2,000 3.000 4,200 5,000 6,000 7,000 8,000 120 9,000 10,000 11,000 12,000 120 13,000 14,000 16,000 12O 18,000 20,000 Elongatio Elongatio IOO 22,000 24,000 26,000 O.OOIO O.OO2O 0.0040 0.0065 0.0077 0.0106 0.0139 0.01/5 0.0223 0.0200 0.0424 0.0626 0.0895 0.1337 0.2227 0.3253 n increased in n increased in 0.5809 0.7.83 0.8504 Inch. O.O2 0.04 0.08 0.13 O.IS 0.21 0.23 0.35 0.45 0.85 1.25 1.79 2.6 7 4-45 8.92 V- '5- liife 14.37 17.01 Pounds. 30,000 30,400 30,600 measui conseq square Continue tions, 2 at 32, 2c Total ek 1.52" = Diametei Tenacity 32,200 i Tenacity Ti^a differei made At fractu % inch fi i inch fr< 2 inches 3 inches Inches. 1.3080 At this poin ing instrume uence of the head of the si d the test wit! ind the piece o pounds per mgation as m 30.40 per cen of fractured per square >ounds. per square i >ounds. wing measur it portions o liter breaking red surface... 'om fracture. Inch. 25.05 26.16 igs of the loose, in vn of the \? el SSf ' .he middle breaking, 1 section, d section, ameter of nen were Cend. 0^698 0.708 0.720 the fastenii nts became drawing doi >ecimen. lout measurii broke near square inch. :asured after t. section, 0.585 inch, origins nch, fracture ements 01 di f the specii A end. 0.585' 0.0099 0.0610 0.2204 2 m. to 0.45^ 4 m. to 0.45; 5m fracture 0.712 'rom fracture 0.710 'rom fracture 0.710 BAR NO. 5 A. COMPOSITION. Original mixture : Cu, 75 ; Zn, 25. Analysis : Cu , 77.84 ; Zn, 21.78. 800 O.OOIO 0.02 22,000 0.5820 11.64 1,200 0.0020 0.04 24,000 0.7053 14.11 2,000 3,000 0.0043 0.0073 O.Og 0.15 25,000 0.7655 26,000 Measuring a pparatus slip 15-31 ped ; con- 4,000 0.0096 O.lg tinued te ;t without i neasurmg 5,000 0.0125 0.25 elongation s. 6,000 7,000 0.0155 0.0206 0.31 0.41 34,040 Broke J inch from A end Total elongation, measured after breaking 8,000 200 0.0250 0.0143 0.50 1.80" = 36 per cent. Diameter of fractured section, 0.585". 9,000 IO,OOt 11,000 12,000 2OO 0.0319 0.0380 0.0469 0.0631 0.0600 0.64 0. 7 6 i ,% Tenacity per square inch, original section, 34,040 pounds. Tenacity per square inch, fractured section, 63,322 pounds. Diameters after breaking. 13,000 0.0933 1.87 Inch. 2 65 At fracture. 585 14,000 A. 6s i inch from fracture 0.232 O 22O3 2 inches from fracture. 685 ' 6 88 3 inches from fracture. 604. 4 inches from fracture " '28 Elongation increased in i m. to 0.4713". Elongation increased in 2 m. to 0.4795". 5 inches from fracture. MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXIIL Continued. BAR NO. 8 B. COMPOSITION. Original mixture : Cu, 60 ; Zn, 40. Analysis : Cu, 59.19 ; Zn, 40.39. Ed K m 2 a X m % o Z I l x - ij IL gri 1 z ~ u Ck " o 2 SET. PS* o Ctf U 2 P SET. | s s Q < S u J w 3 w d Pounds. Inch. Inch. Pounds. Inch. Inch. 2,000 0.0016 0.03 28,000 0.2310 4.62 ooo o . 0040 0.08 200 0.2190 4,000 0.0063 0.13 30,000 0.2648 5-30 e 2OO o. 15 32,400 o. 3235 6.47 6,OOO 0.0103 O.2I 200 0.3062 7,000 8,OOO 0.0113 0.0134 0.23 O.27 34.000 36,000 0.3850 0.4526 7.70 9.05 200 0.0008 200 0-4373 9 OOO 0.0152 o. 30 36,000 0.4860 9.72 IO,OOO 11,000 12,000 2OO 0.0173 0.0220 0-35 0.38 0.44 38,000 _ Measurm 50,520 51,380 0.5700 g apparatus s (Elongat'n n Broke in mk ii .40 calipers). lipped, icasured Witt Idle. 0.0075 i -3 ooo O.O249 o. 50 Total elongation, measured after breaking, 14,000 0.0296 0.59 1.48" = 29.6" per cent. 16 ooo o . 0406 O.bl Diameters of fractured section, 0.672" and 200 0.0336 0.678" (elliptical). 18,000 20,000 200 22,OOO 0.0545 0.0773 O.IIOO 0.0716 1.0 9 2.20 Diameter of piece i inch from fracture, 0,687". Tenacity per square inch original section, 51,380 pounds. Tenacity per square inch fractured section, 24,000 0.1445 2.89 71,762 pounds. 2OO 0.1341 26,000 0.1960 3-94 BAR NO. 9 A. COMPOSITION. Original mixture : Cu, 55 ; Zn, 45. Analysis : Cu, 59.13 ; Zn, 40.36. 2,000 0.0024 O.O5 200 0.1091 3,000 0.0038 0.08 28,000 0.1139 2.28 4,000 0.0056 O. II 30,000 0.1489 2.98 200 0.00l6 32,000 0.1791 3.58 5,000 0.0072 0.14 200 o. 1712 .... 6,000 0.0086 0.17 36,000 0.3017 6.03 7,000 0.0102 0.20 40,000 0.4236 8.47 8,000 O.OII5 0.23 200 0.4077 200 0.0027 44,000 0.6201 12.40 9,000 10,000 O.OI3I 0.0137 0.26 0.27 48,000 53,660 Measuring apparatus slipped. Broke at shoulder, B end. 11,000 0.0152 0.30 Total elongation, measured after breaking. 12,000 2OO 0.0167 0.0082 -33 1.27 = 25.40 per cent. Diameter of fractured section. 0.675". 13,000 0.0l82 0.36 Diameter of piece i inch from fracture, 0.680". 14,000 O.O2OO 0.40 p Diameter of piece 3 inches from fracture, 15,000 0.0217 *.... 0.43 j 0.680". 16,000 0.0240 0.48 1 Diameter of piece 4 inches from fracture, 200 O.O2OI i 0.687". 17,000 0.0259 0.52 Diameter of piece 5 inches from fracture, 18,000 0.0289 0.58 0.704". 19,000 0.0323 0.65 Diameter of piece 6 inches from fracture, 2O,OOD 0.0364 0.73 0.710". 22,000 0.0460 0.92 Tenacity per square inch, original section, 24,000 26,000 0.0614 0.0832 1.23 1.66 53,660 pounds. Tenacity per square inch, fractured section, 28,000 0.1136 1.27 74,975 pounds. S TRENG TH OF BRA SSES. 397 TABLE LXXIV. RECORD OF TESTS BY COMPRESSIVE STRESS. Alloys of Copper and Zinc. Dimensions : Length = 2" (5.08 cm.) ; diameter = 0.625" (*5 cm.). BAR NO. 2. COMPOSITION. Original mixture : Cu, 90 ; Zn, 10. Analysis : Cu. 9.56 ; Zn, 90.42. H 5 H B 2S LOAD. COMPRES- SION. Ii lit LOAD. COMPRES- SION. Ii px Q fsi ft* ** a ggg - O 8 fcJ \ I*' Pounds. Inch. Pounds. Pounds. Inch. Pounds. 500 0.002 1,630 O.IO 12,000 0.294 39, 'H 14.70 1,000 2,000 O.OO4 0.009 3,250 6,519 O.2O 0.45 13,000 14,000 0-334 0.372 42,373 45-633 16.70 18.60 3,000 0.012 9,778 0.60 15,000 0.408 48,892 20.40 4,ooo O.O22 13,038 1. 10 16,000 0.442 52,152 22.10 S, 000 6,000 7,000 0.046 0.083 O.II9 16,297 '9,557 22,816 2.30 4-15 5-95 17,000 \ 18,000 19,000 0.482 0.530 0.563 55,4" 58,671 61,9^0 24.IQ 26.50 28.15 8,000 9,000 0.152 0.187 26,076 29,335 7.60 9-35 i 20,000 Removec o-599 I piece slight 65,190 Jy bent, sui , 29-95 face very 10,000 0.225 32,595 ii 25 rough. 11,000 0.262 35,855 BAR NO. 5. COMPOSITION. Original mixture : Cu, 75 ; Zn, 25. Analysis : Cu, 76.65 ; Zn, 23.08. 2,000 0.0085 6,519 0.43 i 22,000 0.476 71,709 23.80 3,000 0.013 9,778 0.65 23.000 0.502 74,968 25.10 4,000 0.016 13,038 0.80 24,000 0.528 78,228 26.40 5,ooo 6.000 8,000 0.019 0.022 0.032 16,297 26*076 o.95 t.lo l.6o 26,OOO 28.000 30,000 0.562 0.613 0.652 84,747 91,266 28.10 30.65 32.00 9,000 10,000 0.042 0.065 29,335 32,595 2.10 3-25 32,000 34,ooo 0.691 0.734 104!303 110,823 34-45 36.70 11,000 0.109 35,855 5-45 36,000 0-773 117,34* 38.65 12,000 0.154 39, "4 7.70 38,000 0.828 123,860 41.40 13.000 0.203 10.15 i 39,000 0.876 127,119 43.80 14,000 0.243 45,633 12.15 ; 40,000 0.916 130,379 45.8o 15,000 0.273 48,892 13.65 41,000 0.966 133,638 48.30 16,000 0.309 '5 45 42,000 I. Oil 136,898 50.55 17,000 18,000 0.339 0.366 58,671 is! 30 43,000 1.058 Resistance decreased t 52.90 19,000 20,000 21,000 0.399 0.424 0.451 61,930 65,190 68,449 19-95 21.20 22-55 34,000 1 1.150 110,822 57.^0 Removed piece squeezed out of shape with a diagonal crack on one side. 3Q8 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXIV. Continued. BAR NO. 9. COMPOSITION. Original mixture: Cu, 55 ; Zn, 45. Analysis: Cu, 55.15 ; Zn, 44.44. u Z k Ed z &. 3 a o H - o & Z H a Z H LOAD. COMPRES- SION. K U u z Z LOAD. COMPRES- SION. il jjjeJB e "- 1 q o 111 &1 N-t Q 3 m u Pounds. Inch. Pounds. Pounds. Inch. Pounds. 1,000 0.005 3,259 0.25 20,000 0.150 65,190 7-50 2,000 0.008 6 ,5 I 9 0.40 22,000 0.173 71,709 8.65 3,ooo 4,000 5,000 6,000 O.OIO O.OI2 0.014 0.016 9,778 13,038 16,297 0.50 O.CO 0.70 0.80 24,000 26,000 28,OOO 30,000 O.2O2 0.227 0.253 0.280 78,228 84,747 91,266 97,785 10.10 "35 12.65 14.00 7,000 0.019 22,816 0.95 32,000 0.299 I0 4'33 14-95 8,000 0.023 26,076 34,000 0-335 110,822 16.75 9,000 0.026 29,335 1.30 36,000 0.362 "7,34i 18, 10 10,000 0.032 32,595 1.60 38,000 0.388 123,860 19.40 11,000 0.040 35,855 2.00 39,000 0.405 127,119 20.25 12,000 0.050 39, "4 2.5O 40,000 -4 1 5 T 3,379 20.75 13,000 14,000 0.061 0.075 42,373 45,633 3-05 3-75 41,000 41,500 0.436 0.452 133,638 135,268 21.80 22.60 15,000 16,000 0.087 O.IOO 48,892 52,152 4-35 5-00 42,000 Broke su ddenly, a sm 136,898 all piece br< :aking off 17,000 I<5,COO 0.113 0.121; 55,4" 58,671 5.65 6.25 from upper corner. Bent slightly. 19,000 0.138 61,930 6.90 BAR NO. II. COMPOSITION. Original mixture : Cu, 45 ; Zn, 55. Analysis: Cu, 47.56 ; Zn, 52.28. 1,000 O.OO2 3,259 O.IO 26,000 O. IO2 84,747 5-io 2,000 O.OO7 6,519 0-35 28,000 0.115 91,266 5-75 3,000 O.OIO i 9 ' 77 8 0.50 30,000 0.130 97,785 6.50 4,000 O.OI1 o.SS 32,000 0.147 *4,393 7-35 5,000 0.013 16,297 0.65 34,000 0.164 110,822 8.20 6,000 0.014 19,557 0.70 36,000 0.188 117,341 9.40 7,000 0.016 ? 2 ,8t6 0.80 37,000 0.198 120,600 9.90 8,000 0.018 26,076 0.90 38,000 0.21O 123,860 10.50 9,000 0.019 29,335 0-95 39,000 O.221 127,119 ".05 10,000 O.02I 32,595 1.05 40,000 0.239 130.379 "95 12,000 O.028 39, "4 1.40 41.000 0.253 133,638 12.65 14,000 0.037 45,633 1.85 41,500 0.267 135,268 13-35 16,000 18,000 20,000 22,000 0.046 0.056 O.o66 0.078 52,152 58,671 65,190 2.30 2.80 3.30 3.90 42,000 42^500 just as Fracture O.272 beam rose, diagonally a 136,898 138,528 :ross the mic 13.60 Broke die of the 24,000 0.000 78^228 4.50 specimen. STRENGTH OF BRASSES. 399 TABLE LXXV. RECORD OF TESTS BY TRANSVERSE STRESS. Alloys of copper and zinc. Dimensions: Length, 1= 22" ; breadth, 6= l" (2.54 cm.) ; depth, d= i" (2.54 cm.). BAR NO. 4. COMPOSITION. Original mixture : Cu, 80; Zn, 20. Analysis: Cu, 81.91 ; Zn, 17.99. LOAD. DEFLECTION. SBT. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 10 20 130 160 200 3 % % 400 3 400 Inch. 0.0042 0.0080 0.0124 0.0206 0.0296 0.0363 0.0449 - Inch. Pounds. 49o 440 460 480 Soo 520 540 56o 580 600 620 Bent dow Breaking Modulus Inches. 0.4414 0.5885 0.7520 0.959 1.1763 1.3463 i.6.'6 3 1.86 2.22 2.62 3-2? n without load, P = :>f rupture, Inches. 9,030,560' 10,708,667 11,349,217 12,339,278 12,469,814 1,189,949 0.0056 Beam sinks slowly. 0.2445 0.0544 0.0692 0.3352 12,350,618 ,327,32o 9,141,138 6,074,807 3,405,686 breaking. E 620 pounds. R 3/V R *b&- 641,107 ar removed. 21,193- BAR NO. 5. COMPOSITION. Original mixture : Cu, 75 ; Zn, 25. Analysis ; Cu, 76.65 ; Zn, 23.28. 10 20 120 160 200 3 240 280 320 360 4o 3 400 0.0024 0.0066 0.01II 0.0204 0.0288 0.0354 0-0439 0.0514 0.0620 0.0772 0.1094 0.2010 4f 460 480 500 520 540 s ? e 6?o 640 10 Bent with Breaking Modulus 0.4110 0.5396 0.6989 0.9489 l.IO !: 1:3 2 .6 4 3-39 out bireaki load,/>=< if rupture, 0.0059 Beam sinks slowly. 10,347,419 11,260,425 11,964,201 12,978,117 13,081,593 '...'. 1,513,020 t3,407,355 12,967,651 11,902,213 9,448,876 5,714,246 755,634 3 . 19 ng. Removed bar. 540 pounds. *=-^ = "'* 5 - 0.2129 4OO MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXV . Continued. BAR NO. 6. COMPOSITION. Original mixture : Cu, 70 ; Zn, 30. Analysis : Cu, 71.20 ; Zn, 28.54. . *, . &H * o o o H H fl n H D D LOAD. u w SET. p & LOAD. U SET. Bfe u, w Q < J to 14 Q S w S w Pounds. Inch. Inch. Pounds. Inches. Inches. IO 0006? 0.6832 ' 40 80 O.OI72 6,691,260 560 i . 1092 1 20 160 0.0334 O.O4O6 0,337,393 1,338,883 10 580 600 1.1467 1.3462 1.55 1,113,771 i. So " ' -R' 0.0052 * "QA " V" 240 280 o 0680 660 2.45 320 360 400 3 440 0.0794 0.0957 o. 1268 o 2147 Beam sinks 0.0408 ",595,933 10,823,479 9,076,471 680 700 Bent will Breaking 2.80 3-30 lout break load, P = ng. Remov 700 pounds. 610,324 ed bar. 480 0.4258 Modulus of rupture, R = ^rj 2 = 24,468. 500 0.5396 2,660,088 BAR NO. 7. COMPOSITION. Original mixture : Cu, 65 ; Zn, 35. Analysis : Cu, 66.27 ; Zn, 33.50. IO 20 40 80 120 160 200 3 240 280 320 360 400 440 480 520 1^ 600 0.0028 0,0058 0.0124 0.0233 0.0317 0.0384 0.0466 0.0546 0.0642 0.0728 0.0836 0.0948 O.IIIO 0.1454 0.2128 0.4680 0-5958 6,1 640 660 680 700 7 20 740 760 7 80 Repeate 780 800 820 IO Bent wi Bar rem Breakin Modulu 0.6734 0.8^36 1.0268 1.2058 1.41 1-59 1.79 2.04 d . 2 ' 34 2.84 3-34 3-84 hout breal oved. er load. P = 3 of ruptur 0.5538 0.0033 O.OIT2 Beam sinks slowly. 9,168,783 9,759,049 10,759,827 11,843,014 12,198,812 1,411,082 12,493,727 12,396,423 12,493,727 12,239,668 11,992,925 11,226,865 680,796 . 3-54 cmg. = 820 pounds. e '*-^- 28 '9. 6,9M,525 2,862,360 STRENGTH OF BRASSES. 401 TABLE LXXV. Continued. BAR NO. 8. COMPOSITION. Original mixture : Cu, 60 ; Zn, 40. Analysis : Cu, 60.54 ; Zn, 38.65. LOAD. ' M Q SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 40 80 120 160 200 10 240 280 320 3 60 4 00 10 400 Left unde sistance 10 440 480 520 & 10 640 720 800 10 Inch. o . 0203 0.0291 0.0380 0.0447 -534 Inch. 0.0105 5,488,205 7,835,438 8,795,568 9,969,625 10,431,698 10,678,327 10,816,556 10,869,170 11,067,272 Pounds. 800 Resistanc 10 840 880 900 920 $ 980 1,000 1,100 Resistanc Resistanc Resistanc pounds. 1,130 Randowr 1 maximu pounds. Bent with Breaking Modulus < Inches. 0.5090 e decreasec 0.5275 0.9685 0.9885 1.04 1.26 1-33 i 53 I.fc2 2.6 7 2 decreasec ; decreased ; decrease 2.72 2.75 pressure s n resistan out breaki load, P = >f rupture, Inches. [ in i hour to 0.3224 782 pounds. 2,535.900 0.0626 0.0721 0.0820 0.0906 O.IOOO O. IO2O r strain 18 to deflectu 0.0135 1,719,298 in 30 sec. to 1,026 pounds, in i m. to 1,020 pounds, i in 17 hr. 30 m. to 990 hours ; deflection and Te- rn unchanged. 0.1IOI 0.1193 0.1290 0.1425 0.1585 0.1747 0.2555 0.5021 11,130,936 11,206,425 11,227,419 10,945,596 io,543i585 crew about i ce to rapid ng- 1,140 pounds R 3Pl nch further; motion 1,160 = 38,968. 0.0283 0.3060 10,203,600 7,848,884 4,437,784 ~ zbd* BAR NO. 9. COMPOSITION. Original mixture: Cu, 55 ; Zn, 45. Analysis: Cu, 55.15 ; Zn, 44.44. 20 120 1 60 200 10 2 4 280 320 300 400 10 $ 520 a 10 640 680 700 720 800 10 800 0.0080 0.0148 0.0285 0.0398 o 0505 0.0612 0.0800 0.0900 0.1004 0.1110 0.1317 860 880 900 920 940 960 Resistanc Resistanc Resistanc 10 920 940 960 980 1,000 I,O2O 1,100 1, 160 Crackling 1,180 1,200 Breaking Modulus < .0364 .1250 1953 .2722 .3423 .4647 e decrease e decrease e decrease 4785 5175 :&S :?? 5 .24 .65 sound hea 2.79 Bar ben from u load, / = >f rupture, 0.0080 7,888,340 8,194,687 8,800,055 i 9,247,321 9,538,189 | 8,756,005 9,080,354 9,302,585 9,466,607 8,864,649 2,197,622 3 in 5 min. to i in 20 min. t< i in 16 hr. to 1.2233 950 pounds. 5 942 pounds. 916 pounds. 0.1496 0.1790 0.247 0.2645 0.3306 0.3951 0.5060 0.5315 0.5833 0.8367 o!8 5 8i 0.1663 8,584,370 | 7,826,643 \ 7,069,010 5,297,071 1,653,646 1,433,283 jrd from bar. . ar.d supports slid out ider it. i ,200 pounds. *-i-M*. 4,839,294 0.6250 2,790,663 i i 4O2 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXV. Continued. BAR NO. 10. COMPOSITION. Original mixture : Cu, 50 ; Zn, 50. Analysis : Cu, 49.66 ; Zn, 50.14. tb h > H LOAD. DEFLEC- TION. SET. en CJ li LOAD. DEFLEC- TION. SET. 32 gg 33 is 8" i w Pounds. Inch. . Inch. Pounds. Inches. Inches. 20 0.0065 680 0.5990 40 O.OIIO 10,711,665 720 0.6700 3> l6 5,537 80 0.0219 10,760,578 760 0.7647 120 0.0330 10,711,665 i 800 0.6813 2,704,656 160 O O42O 10 986 324 | IO o 6600 2OO A slight cr strain re u.u^y 0.0509 acklmg so mained or und was hea i the bar, tf 11,574491 rd while the ie deflection 800 840 880 0^8713 9493 1.0613 v * wu yy being he 10 200 Id constan 0.0025 0.0509 L Beam sinks 920 940 cracks we. i . 1690 Onapplyir re heard. ig the stress s but there wz everal si ight is no visible 240 280 0.0623 0.0773 slowly. 11,347,832 10,670,093 appearance of breaking. The resistance sud- denly decreased, and on balancing the scale beam was found to be 580 pounds. O . I O X) ego 360 - I 337 ..... 7,931,600 500 10 A ^3/V 1.1195 400 0.1736 6,787,347 Applied stress again, and the resistance 10 440 480 520 0.2220 0.2752 0.3291 0.0816 ^' 5,838,341 : 4> 6 54,4 1 5 reached 500 pounds when the bar broke. The crackling sound noticed first at 200 pounds continued throughout the test while the bar was strained, even when the deflection was 560 0.3909 held constant for several minutes. 600 0.4568 3,869,144 Breaking load, P = 940 pounds. 10 640 0.5182 0.3165 Modulus of rupture, R = ~j~r^ 331467. ALLOYS OF COPPER AND ZINC. BAR NO. 32. Resistanc 3 751 800 820 840 860 880 900 920 % e decrease 0.3364 0.3490 0.3583 0-379 0.3948 0.4145 0-4H3 0.4518 0.4669 0.4905 d in 22 hrs. to 0.1638 751 pounds. 980 1,000 I,C2O I 040 0.5122 0.5302 0.5444 o. S7i8 '.'.':.'.'. 5,718,889 :::::: 1,080 0.6140 5,333*432 1,100 Broke in middle just as beam rose. Breaking load, P= 1,100 pounds. Modulus of rupture, R = - 7-= = 40,189. 2 od* The crackling sound noted at 520 pounds con- tinued till the end of the test, even when the de- flection was held constant for several minutes. 6,283,536 STRENGTH OF BRA TABLE LXXV. -Continued BAR NO. 33. COMPOSITION. Original mixture : Cu, 42.5 ; Zn, 57.5. Analysis: 01,43.36; Zn, 56.22; Pb, LOAD. g e SET. \\ LOAD. 1 SET. I 3 K H Q If 2 W j E S il Pounds. Inch. Inch. Pounds. Inch. Inch. IO 0.0030 360 ^o^ 20 C 0.0164 0.0279 5, 95, * 34 5,246,355 3 7 9 0.0115 12,628,285 0.0850 1 20 -0354 8,246,381 480 0.0909 ...... 12,882,137 160 200 3 0.0421 0.0497 0.0063 9,271,468 9,817,123 520 540 Breaking 0.0982 Broke jus load, />= t as beam n> 540 pounds. 12,918,211 se. 240 280 0.0556 0.0614 10,530,451 11,125,005 Modulus of rupture, /?= 7 17,691. 320 0.0672 11,616,928 BAR NO. 39. COMPOSITION. Original mixture: Cu, 12.5; Zn, 87.5. Analysis: Cu, 12.12; Zn, 86.67; Pb, 1.22. TO 600 2O 0.0056 o 0.01.18 40 0.0128 8,982,413 Resistance increased in 10 minutes to ro 80 0.0234 9,826,913 pounds. 12O 10,484,031 o 0114 160 200 0.0430 0.0526 i,695,338 10,929,173 640 680 0.1663 0.1796 11,061,926 10,882,925 240 0.0641 10,762,079 0.2116 10,323,831 280 800 o 2261 320 0.0818 11,244,489 3 0.0378 360 0.0921 Beam sinks ",235,33 2 840 0.2450 9,8S4,99 X slowly. 880 0.2624 400 0.1016 11,316,427 920 0.2856 3 0.1115 0.1216 0.0064 11,342.857 11,346,204 960 I.OOO Breaking 0.3124 Broke jus load, P^ t as beam ro i,ooo pounds 8,832,898 se. . 520 56o o. 1316 0.1421 :::::: ",359,423 "3 2 7<574 Modulus of rupture, R = ~r^ *^ 35,026 BAR NO. 41. COMPOSITION. Original mixture : Cu, 2.5 ; Zn, 97.5. Analysis : Cu. 2.45 ; Zn, 96.43 ; Pb, 1.05. 440 o 1895 40 0.0154 8,117,624 480 0.2225 6,588,717 80 O.02 ^r 4 ::: ~^^- ^- _ ^-- ^^ ^-^ ^ v,- -- -; ipEiqib^frfe ~\ v^ N^ 880 igl 8.60 ""**"- --^ 8.10 8.20 8.00 7.80 ff.60 - > ^ ^ : c "-S^ g - n \ _ -i X m \ mm 7.40 n : 7.20 '1 ::.:.::. x 9.10 COPP - s< ""-*- - NO ER'JO W 86 80 75 70 65 00 55 50 45 40 35 W 25 20 15 10 Composition by Analysis 5 Z the elastic limit is not clearly defined, but appears to approach more nearly to the ultimate strength in tensile than in other tests. In brittle alloys, containing from 56.22 to 85.10 per cent, zinc, the elastic limit is not reached until fracture takes place. From 85.10 per cent, to pure zinc, the ratio decreases by transverse tests, while in tensile tests the ratio apparently re- mains at 100 per cent, till 96.43 per cent, zinc is reached. In torsion tests the elastic limit begins to be less than the ulti- mate strength after 86.67 per cent, zinc, the ratio decreasing as the percentage of zinc increases. S TRENG TH OF BRA SSES. 4 1 1 242. The Moduli of Elasticity of the copper-zinc alloys are variable according to a law which is probably nearly repre- sented by the upper curve in Figure 20. The modulus for copper is low, and the figure gradually rises as zinc is added, until passing zinc 25, it falls again, passing a mmimum at about zinc 50, and a second maximum not far from zinc 75, and falls off rapidly to a minimum at pure zinc. Further in- vestigation is needed to determine to what extent these fluct- uations are due to chemical and what to physical causes. The Author is inclined to believe that sound castings contain- ing large amounts of copper would give higher figures. The moduli of elasticity given in the above table were se- lected from the records of test by transverse stress. The average figure for the alloys is nearly 13,000,000 (913,900 kilogs. per sq. cm.). The variation of the figures of bars of different composition does not have any relation to density, strength, or other mechanical property, but follows a law of its own. There appears to be an increase of the modulus with in- crease of percentage of zinc up to the alloy containing 16.98 per cent, of zinc. It then appears to be nearly uniform from 16.98 to 36.36 zinc. From 36.36 zinc to 44.44 zinc there is a regular and rapid decrease, and from 44.44 zinc to 52.28 zinc there is a regular and rapid increase. This break, almost a cusp in what might otherwise be a regular curve, is indicated by all observations between the limits of 36.36 and 52.28 zinc. The increase in the modulus continues from the alloy con- taining 52.28 per cent, zinc to that containing 66.23 P er cent, zinc. The latter alloy gives the maximum modulus of the series. From this point there is a rapid decrease to pure zinc, which gives the minimum modulus. The bars which make this break include the strongest bars of the series, and those which exhibited the phenomena of irregularity in increase of deflection under transverse stress and of emitting the crackling sound (cry of tin) when held at a constant deflection. They also include metals of a wide range of ductility r.nd hardness, and of a structure varying from fibrous to coarsely granular. 412 MATERIALS OF ENGINEERING NON-FERROUS METALS. 243. The Curve of Specific Gravities is presented on the lower part of the same figure, under that of the moduli of elasticity. This curve is not as smooth as that'given for the bronzes, and it may ultimately be found necessary to revise it to some extent. The general method of variation is very similar to that given for copper-tin alloys. Its equation may be taken as approximately, D 7 + 0.019 C, in which D is the specific gravity and C the percentage of copper. It is not, however, a straight line, but has probably FIG. 21. COMPARATIVE DUCTILITY. TRANSVERSE - DEFLECTION i ^ 3.00 S.7E 2.50& 2.00 .CO 0.12 0.40 0.08 0.20 0.01 COPPER95 iX) 85 80 75 70 65 60 55 SO 45 40 S5 Composition by Analysis 20 15 10 5 ZINC the same smooth and moderate curvature observed in that given for the bronzes. A smooth curve osculating that here given on the upper side of the latter, is perhaps the true curve. It would terminate at very nearly or quite S. G. = 9 on the copper side, and at S. G. = 7.15 at the zinc end. 244. Comparisons of Ductility of the copper-zinc alloys are graphically exhibited in the above figure, as determined by the several methods of test. It is seen that it varies in the opposite direction to the change of strength with variation of Composition and to be different in its distribution from that STRENGTH OF BRASSES. 413 observed in the copper-tin alloys. All bars containing be- tween 16.98 and 38.65 per cent, zinc have a high degree of ductility, the mean extension of the two pieces of each bar varying from 20.67 to 38.5 per cent. With the increase of zinc beyond 38.65 per cent, the ductility decreases till 52.28 per cent, zinc is reached, the mean extension of the alloy of this composition being only 0.79 per cent., or but little more than one-fiftieth of the maximum. From 52.28 to 70.17 per cent, zinc, the elongations could not be determined, most of the pieces being tested in their original rectangular sections. Their extensions were, without doubt, much less than 0.79 per cent., as the test-pieces appeared nearly as brittle as glass. From 77.43 to 96.43 per cent, zinc the elongations very slowly increase, that, of the former composition being only 0.12 per cent., and that of the latter 0.88 per cent. The form of the curve and one test showing an exception- ally high ductility of 607 degrees angle of torsion, or an ex- tension of 2.5011 (No. 3, 89.80 copper, 10.06 zinc), indicate that the maximum ductility of the alloys of copper and zinc is found among alloys containing small quantities of zinc. From 16.98 to 61.05 zmc there is a very regular decrease of ductility, the latter having an extension of 0.00002, or only about T^rJoorth of the maximum. From 61.05 to 88.88 zinc there is a uniform want of ductility, the figures of extension varying from 0.00002 to o.oooii. From 88.88 zinc to pure zinc, the ductility increases. 245. A Summary of many of the results of the tests which have been described will be found included in the table al- ready given at the end of Chapter V., in which the brasses are described. CHAPTER XI. STRENGTH OF KALCHOIDS AND OTHER COPPER-TIN-ZINC ALLOYS. 246. The Kalchoids. The bronzes and brasses were not distinguished by early Greek and Latin writers, who applied the same names to both (Greek, Kalchos ; Latin, Acs.). It has also been common to add to the copper-tin, or bronze, alloys small proportions of zinc, and lately, to the copper-zinc alloys, or brasses, small quantities of tin, thus forming an in- termediate collection of indefinite number and proportions, to which may be here applied the indefinite terms of the ancients, and which may be called the kalchoids, or kalchoid alloys. These and solders and other copper-tin-zinc alloys naturally fall into one group. The effect of substituting a small quantity of zinc for tin in making the bronzes is not perceivable except as making them a little less subject to " cold shuts," or blow-holes and similar defects, making them a little softer and a trifle weaker and giving them slightly better working qualities when turned in the lathe or otherwise shaped with cutting tools. The effect of substituting a small proportion of tin for zinc in the brasses, however, is very marked, causing increased hardness, strength, rigidity and elasticity, and, if the propor- tions of copper and zinc are about equal, making the alloy too hard and brittle to work. In general, the effects of the two metals, zinc and tin, upon copper are similar, but that of adding tin is much more observable than that of introducing zinc. It was found in collating the results of investigations made by the Author for the U. S. Board and in other researches, that the effect of one part tin is nearly equivalent to two parts of zinc. These facts are well illustrated in the account of that work STRENGTH OF KALCHOIDS. 415 to be presented in the present chapter. They are well shown also, in experiments on " sterro-metal." 247. Sterro-metal, tested at Woolwich, exhibited a te- nacity somewhat variable with composition, but always con- siderable, as seen below.* Its stiffness and resistance to abrasion were also found to be very great. The tenacity may be taken at an average of 60,000 pounds per square inch (4,218 kilogs. per sq. cm.), its elastic limit at one-half that amount, and its elongation at 0.07. The test pieces used were three diameters long. TABLE LXXVI. TENACITY OF STERRO-METAL. Breaking weight, Ibs. per square inch. Kilogs. per square cm. Ultimate elongation at breaking point in inches. Treatment Mixture. 60,020 4,213 .1 as received. Austrian. 46,060 3,386 .05 j Copper, 60 ; zinc, 39 ; \ cast in sand. iron, 3 ; tin, 1.5. 43,120 3,032 .015 ) I 54,220 52,080 3,819 3,662 .016 .02 cast in iron. j cast in iron and ( annealed. 1 Copper, 60; zinc, 44; iron, 4 ; tin, 2. 62,720 4,410 045 forged red hot. \ 70,806 4078 ) cast in iron and "70 8d^ ' V / e T2I f forged red hot. /^>*f3 76,160 3, ** 5,355 Copper, 60 ; zinc, 37 ; iron, 2 ; tin, I. 84,920 5,985 Copper, 60 ; zinc, 35 . iron, 3 ; tin, 2. 60,480 76,160 84,920 4,252 5,355 5,9^5 after simple fusion, forged red hot. drawn cold. ] Copper, 55.04 ; spelter, y 42.36 ; iron, 1.77 ; tin .83. 62,720 4,410 .... after simple ] fusion. 73,680 5,040 forged red hot. drawn cold and reduced from Copper, 57.63; spelter, y 40.22; iron, 1.86; 82,880 5,827 .... \ 100 to 77 trans- tin, 0.15. 1 verse sectional area. } Strength of Materials ;" Anderson, Lond., 1872. 41 6 MATERIALS OF ENGINEERING NON-FERROUS METALS. This greater tenacity, as compared with brass and Muntz metal, is probably partly due to the presence of iron, but largely also to the one or two per cent. tin. As will be seen later, the Author has obtained higher figures by the use of tin alone. 248. The Copper-Tin Zinc Alloys were made the sub- ject of a special and systematic investigation, at the request of the Committee on Alloys of the U. S. Board of 1875, with a view to the determination, not simply of the strength and other properties of specific combinations, but to ascertain the law governing the variation of such useful qualities with vari- ation of composition, in such manner that, by the study of a limited number of these alloys, the properties of all possible combinations of the three metals might be fully determined. Before entering upon this investigation it, therefore, became necessary to devise a plan and to invent a method of research, which should enable the Author so to choose the set of alloys to be studied as to make their number a minimum, while so fixing their proportions as to distribute them with a satisfac- tory degree of uniformity over the whole field to be ex- plored, thus making the research complete and productive of a maximum result at minimum cost of time, labor, and money. 249. The Plan of Investigation, if it could be made thus effective, should evidently lead not only to the determination of the strength and elasticity, ductility and resilience, and other important properties of all possible alloys of copper with zinc, copper with tin, and tin with zinc, and of all copper-tin- zinc alloys, but should also reveal the composition of the alloy of maximum strength or other quality, or combination of qualities, that could possibly be formed and that man can make, using these elements. Such a plan was devised by the Author. Its principle is as follows : * In any equilateral triangle, B, C, D, Fig. 22, let fall per- pendiculars from the vertices to the opposite sides, as for * On a New Method of Planning Researches, etc., by R. H. Thurston. Proc. Assoc. for Advancement of Science, vol. xxvi. Trans. Am. Soc, C. E. 1881, No. 214. STRENG TH OF KALCHOIDS. 4 1 / example, C E. From any point within the triangle, A, let fall perpendiculars A G, AH,A~F, and draw A B, A C, AD to the vertices, thus obtaining three triangles, A B D, ABC, A CD; their sum is equaled i-i to the area of the whole figure BCD. FlG - 22 - Now we have, since the triangle is equilateral, and CE x BD _ A F x BD A G X B C AH x CD CE x .> = (AF+AG + AH) x BD\ and which follows wherever the point A may be situated ; it is true for every point in the whole area BCD. Assuming the vertical C E to be divided into 100 parts ; then A F + ~AH + ~A~G = 100 and , , L, measures the rela- 100 100 100 tion of each of the altitudes of the small triangles to that of the large one. But we may now conceive the large triangle to represent a triple alloy of which the areas of the small triangles shall each measure the proportion in which one of the constituents enters the compound, and B CD = 100 per cent. = (A F + A G + A H) B D, or CE = 100 per cent. = A^F + A~G + A H per cent, and the altitude of each small triangle measures the percentage of some one of the three elements which enter that alloy which is identified by the point. Thus every possible alloy is represented by some one point in the triangle B CD, and 27 41 8 MATERIALS OF ENGINEERING NON-FERROUS METALS. every point represents and identifies a single alloy, and only that. The vertices B, C, >, in the case to be here con- sidered, represent respectively, copper = 100, tin = 100, zinc = 100. 250. Alloys Chosen for Test. Thus, having determined a method of studying all possible combinations, the Author next prepared to examine this field of work in the most efficient and complete manner possible, with a view to deter- mining, by the study of a limited number of all possible cop- per-tin-zinc alloys, the properties of all the numberless, the infinite, combinations that might be made, and with the hope of detecting some law of variation of their valuable qualities with variation of composition, and thus ascertaining which were the most valuable for practical purposes. With this object in view, the triangle laid down to repre- sent this research, was laid off in concentric triangles, Fig. 23, varying in altitude by an equal amount 10 per cent. on which were laid out the following series of alloys : FIG. 23. STRENGTH OF KALCHOIDS. TABLE LXXVII. SCHEDULE OF COPPER- TIN-ZINC ALLOYS TESTED. 419 COPPER. ZINC. TIN. COPPER. ZINC. TIN. 10 10 80 30 40 30 10 2O 70 30 50 2O 10 30 60 30 60 10 10 40 50 40 IO 50 10 50 40 40 20 40 10 60 30 40 30 30 10 70 20 40 40 20 10 80 10 40 50 IO 20 IO 70 50 IO 40 20 20 60 50 20 30 20 30 50 50 30 20 2O 40 40 50 40 10 20 50 30 60 10 30 2O 60 20 60 20 20 20 70 TO 60 30 10 30 10 60 70 10 20 30 2O 50 70 2O 10 30 30 40 So 10 10 These alloys were first tested in the Autographic Record- ing Machine, and their strain-diagrams carefully studied. It was found that only a few were of value, and that the alloys represented by that part of the field lying on the tin-zinc side of a line running from copper = 70, tin = 30, zinc = o, to the point copper = 40, zinc = 60, tin = o, were too soft or too brittle and weak to be useful. The research was now re- stricted to the examination of alloys lying nearer the point copper = 100, i.e., the upper vertex of the triangle as seen in the figure, and all such alloys were tested by tension, com- pression, and torsion, and by transverse stress. 251. Details of the Work. In the study of these copper- tin-zinc alloys, the same general method of experiment was adopted as in the investigations of the brasses and the bronzes already described.* To ascertain what results would be obtained by casting together brass and bronze of known properties, the first series * The observer entrusted with this work, under the direction of the Author, was Mr. M. I. Coster, M. E. 420 MATERIALS OF ENGINEERING NON-FERROUS METALS. of ternary alloys was prepared in proportions based upon results obtained in the earlier researches relating to copper-tin and copper-zinc alloys as the strongest, the weakest, the most and the least resilient alloys respectively ; and by various com- binations of these, twelve alloys were obtained. This constitutes the first series. No. 5 (Cu 88.135, Sn 1.865, Zn 10) was made up of the most resilient bronze and brass ; its resilience was less than that of either of its com- ponents. No. 6 (Cu 45, Sn 23.75, Zn 31.25), composed of the least resilient bronze and brass, was less resilient than the brass, but more so than the bronze. No. 7 (Cu 66.885, Sn 1.865, Zn 31.2), formed of the most resilient bronze and the least resilient brass, was much less resilient than the bronze, but considerably more so than the brass. No. 8 (Cu 66.25, Sn 23.75, Zn 10) was made of the least resilient bronze and. the most resilient brass. It was less resilient than either the bronze or the brass. The greatest resistance to torsion of all the bars of the series was exhibited by No. 7, and the mean of its torsional moments exceeded that of all the others. It was of a more homogeneous structure, and may be con- sidered the best alloy of the series. No. 5 was the most ductile and the most resilient. No. 12 (Tobin's alloy, Cu 58.22, Sn 2.30, Zn 39.48) was shown by all the tests to be the strongest alloy. It exceeded good wrought iron in strength, and was sufficiently resilient to resist shocks. Its modulus of elasticity, as calculated from the transverse test, is 11,500,000 (metric, 808,450). From the results obtained, it is evident that it does not necessarily follow that two alloys which are separately good and strong, or poor and weak, will, when cast together, give an alloy which is similarly strong or weak. A second series was next tested, to afford a general survey of the field containing what were known to be good alloys and to locate approximately the position of the best com- positions. In this set, 36 alloys were made by all possible combina- tions obtainable by a difference of 10 per cent, in the three metals. As a rule, the bars of this series were not as strong STRENGTH OF KALCHOIDS. 421 as those of the first series ; this may have been due to the fact that the other bars were cast under greater pressure. It was noted that if the amount of tin does not exceed 40 per cent., the alloys are strengthened by an increase of copper up to 20 per cent. If further addition of copper is made the alloys become brittle, and when the copper amounts to 50 per cent., compositions are obtained which are practically worthless. If more copper is added the alloys increase in strength until a maximum is attained for the greatest per- centage of copper in their series, i. e., 80 per cent. When the amount of tin exceeds 40 per cent, the alloy becomes weaker as the percentage of copper is increased. Up to 20 per cent, of copper, an increase of tin causes a decrease of strength and an increased ductility. Between 20 per cent, and 40 per cent, of copper, the alloys become stronger for an increase of tin up to 20 per cent. They then become weaker as the tin is further increased. When the amount of copper exceeds 40 per cent, an increase of tin again appears to weaken the alloy ; this is only true when the least quantity of tin amounts to 10 per cent., as in this series. The results of tests of this series show that more than five-sixths of the alloys in the field here explored are comparatively worthless. A third series of 24 alloys was next made for the purpose of locating the best alloys still more precisely, and to deter- mine the properties of those lying within the now greatly restricted field of investigation, which had now been con- tracted to a small fraction of the total area. A line was drawn from 45 per cent, copp'er on the zinc side of the triangle to 72.5 per cent, of copper on the tin side. These points represent the percentages at which the marked change of color and of strength in the brass and bronze alloys takes place. The alloys of this series were all located in that portion of the field containing all the more useful composi- tions and were made to vary in composition by 5 per cent. The castings of this and succeeding series had smoother sur- faces than those preceding. Some volatilization of zinc took place during the pouring of the molten metal in the first three numbers of the series. A great difference was noted in 42 2 MA TERIA L S OF ENGINEERING NON-FERRO US ME TALS. the results obtained from the upper and lower ends of the bars ; the upper end giving the best figures. The difference between the strain-diagrams of these two portions of the bar was such that the former in one case had an ordinate of 0.92 inch at the elastic limit and a maximum ordinate of 1.76 inches, while the other end had for its ordinate at the elastic limit 1.38 inches and fora maximum ordinate 1.56 inches. The general laws exhibited by the curves representing the properties of alloys of copper, tin, and zinc, were ap- proximately determined from the tests of this series. For a certain amount of copper (when this exceeds 50 per cent.) an addition of tin increases the brittleness, while zinc increases the ductility of the alloy. If the amount of copper is increased it is necessary also to increase the tin in a certain ratio in order to obtain an alloy of about the same percentage of ductility. It was shown by the tests of this series that if the composition has 80 per cent, of copper, 10 per cent, of tin will make it quite ductile, while 15 percent, of tin will render it rather brittle. Hence the amount of tin necessary to make a strong alloy, when there is 80 per cent, of copper, lies somewhere between 10 per cent, and 15 per cent., and an alloy composed of Cu 80, Sn 12.5, Zn 7.5 was taken as very nearly representing the best pro- portions. Next, a fourth series was made. This series consisted of but five alloys, which were chosen without regard to regularity, but to determine doubtful points previous to the preparation of the final series. No. I (Cu 55, Sn 0.5, Zn 44.5) contained but 0.5 per cent, of tin, and is the only instance in the entire investigation where so small an amount of any of the metals was introduced in an alloy. This was done in order to ascer- tain the effect of so small a percentage when added to an alloy of known properties. This alloy was brass (Muntz metal, nearly), and 0.5 per cent, of tin was substituted for zinc, thus leaving but 44.5 per cent, of zinc. The smallest quantity of zinc in any bar of the series was 2.5 per cent, in No. 5 (Cu 82.5, Sn 1-5, Zn 2.5). The difference in ductility between the two ends of the bare was more marked in No. 2 STRENGTH OF KALCHOIDS. 423 (Cu 67.5, Sn 5, Zn 27.5) than in any other alloys thus far tested. The upper end, No. 2 A, was turned in the auto- graphic machine through an angle of 70.8, while the lower end, B, broke after it was turned through 7.5, the latter being only about 10 per cent, of the former. This difference was exhibited, in a more or less marked degree, by all the bars of this series. Comparing the data thus obtained by test of the several sets of alloys made as above, it became evident that all the most useful alloys are located between the line drawn from 88 per cent, of copper on the bronze side of the triangle to 65 per cent, of copper on the brass side, and from 83 per cent, of copper on the bronze side to 55 per cent, on the brass side. Twelve alloys in this part of the field were next made, varying by 2.5 per cent., omitting those which had already been tested and a few not absolutely necessary to the determination of the law of variation of strength. The re- sults obtained fully confirmed previous conclusions. It was found that, in nearly all cases, the upper portion of the bar was considerably more ductile than the lower and also gener- ally stronger. All the alloys of this series were strong ; the strongest, No. I (Cu 60, Sn 2.5, Zn 37.5), had a mean maxi- mum torsional moment of 216 foot-pounds (tenacity about 40,000 Ibs. or 2,892 kilogs.), and the weakest, No. 7 (Cu 72.5, Sn 10, Zn 17.5), 122 foot-pounds (tenacity about 24,000 Ibs., or 1,672 kilogs.). All the alloys located between the lines forming the boundaries of the set of compositions in this series are useful and strong. Commencing with the strong brasses on one side of the triangle, greater strength is ob- tained when any appreciable amount of tin is added ; as the quantity of tin is increased, the alloys continue to be superior in strength to either the brasses or the bronzes ; but their strength gradually decreases with the diminution of the amount of zinc, if the alloy contains more than 60 per cent. of copper, until we obtain strong bronzes on the other side of the field. An addition of tin for the same amount of copper, if this addition does not exceed 30 per cent., increases the ductility of the alloy. In alloys containing 40 per cent, of 424 MATERIALS OF ENGINEERING NON-FERROUS METALS. copper a substitution of a moderate quantity of tin for zinc does not seem to affect the ductility. If the alloys contain more than 40 per cent, of copper, an increase of tin causes a decrease of ductility. The most ductile alloy was No. 8 B, 2d series (Cu 10, Sn 80, Zn 10), which had an angle of tor- sion in the autographic machine of 418.4 ; no other alloy tested contained such a large quantity of tin. From the per- centage of extensions of the alloys having a torsional moment of more than 150 foot-pounds, and strength of more than 30,000 pounds per square inch (2,109 kilogs. per sq. cm.), four curves of maximum strength with a percentage of extension have been constructed (Fig. 27). The lowest curve thus plotted has an extension of 0.03 per cent, and connects the points representing the strong brittle alloys. It starts at 43 per cent, of copper on the brass side and cuts the bronze side of the triangle at 77 per cent, of copper. The other curves have an extension of 3, 7.3, and 17 per cent, respectively. They all appear to converge to a point on the right of the brass side and agree nearly with arcs of circles of about 7 inches radius on the scale of the figure. By means of these curves of extension, alloys of different degrees of ductility can be selected. The effect of tin upon alloys of copper and zinc within limits may be compared to that of carbon on wrought- iron. Commencing with brass of about 55 per cent, of copper, which is of itself ductile and strong, we obtain by the addition of a small percentage of tin an alloy of much greater strength, having a higher modulus of elasticity, but not quite as ductile. By further addition of tin, up to about 2.5 per cent., the alloy becomes gradually less ductile, but it increases in strength. But if more tin is added, we obtain compositions which be- come more brittle as the tin is increased, and at the same time decrease in strength. A slight modification of propor- tions often causes very great changes in the properties of the alloys, as in No. I, 4th series, where 0.5 per cent, of tin, added to ordinary brass produced an alloy stronger than wrought iron. The facts thus brought out are best exhibited by the pro- file map and the model which are to be presently described. STRENGTH OF KALCHOIDS. 425 252. The Method of Exhibiting and Recording Results, which, as devised by the Author for this case, was intended so to present the data secured in the manner described that it could be seen, at a glance, what law, if any, controlled the FIG. 24. COPPER-TIN-ZINC ALLOYS. variation of strength, or of the quality, with change of com- position, and that the investigator could readily determine where to seek the alloy possessing a maximum of any quality, desirable or otherwise, should it happen, as would in all prob- ability be the case, that that alloy had not been included among those studied during the investigation. The plan 426 MATERIALS OF ENGINEERING NON-FERROUS METALS. finally adopted was novel but as thoroughly satisfactory as was that of laying out the work. It was the following : The figures obtained by the test of alloys studied were inserted upon a triangular plan, each in its place as deter- mined, in the manner described in Art. 249, for that compo- sition. When the figures thus obtained had been entered on the triangular map, lines of equal strength, of equal ductility, or of equal resistance could be drawn, as in topographical work lines of equal altitude are drawn, and the map became thus a useful representation of the valuable qualities of all possible alloys. Figure 24 represents such a map * of all copper-tin-zinc alloys. The scale of altitudes is obtained by considering the relation of tension to torsion resistance as 25,000 pounds per square inch (1,758 kilogrammes per square centimetre) for each 100 foot-pounds (13.82 kilogrammetres) of torsional mo- ment for the standard test-specimen, which specimen was turned to a standard gauge, and made ^ inch (1.84 cm.) di- ameter and i inch (2.54 cm.) long in the cylindrical part ex- posed to strain. These facts were also exhibited by another method de- vised by the Author ; thus : Upon a triangular metal base, laid off as above, erect a light metallic staff by drilling a hole for its support at each point laid down as representative of an alloy tested ; make the altitude of each of these wires proportional to the strength of that alloy. There is thus produced a forest of wires, the tops of which are at elevations above the base-plane propor- tional to the strengths of the alloys studied. Similar con- structions may be made to represent the elasticity, the duc- tility, or any other property of all these alloys. Next fill in between these verticals with clay, or better, with plaster, and carefully mould it until the tops of all the wires are just vis- ible, shining points in the now smooth surface of the model. * Reports of U. S. Board testing Iron, Steel, etc. Washington, 1878-1881. The Strongest of the Bronzes ; R. H. Thurston. Trans. Am. Soc. C. E. 1881, no. ccxlv. STRENGTH OF KALCHOIDS. 427 The surface thus formed will have a topography characteris- tic of the alloys examined, and its undulations will represent the characteristic variations of quality with changing propor tions of the three constituents. This was made for the Author, FIG. 25. MODEL OF COPPER-TIN-ZINC ALLOYS. Zn. and was cast in an alloy of maximum tenacity, the plaster cast made as above being used as a pattern. Figure 25 is a representation of this model made from a photograph. 253. General Deductions. The remarkable variations of quality here so strikingly shown attracted attention, and a further investigation was made. These alloys were purposely made without other precau- 428 MATERIALS OF ENGINEERING NON-FERROUS METALS. tions than those observed by every founder, and without using deoxidizing fluxes. The data obtained were consequently quite variable, and the result of this work indicated that the same alloy, especially where the proportion of copper is great, may give very differ- ent figures accordingly as it is more or less affected by the many conditions that influence the value of all brass-foundry products. Some variations in the model are probably due to such accidental circumstances. But, allowing for minor vari- ations, it is evident that the alloys of maximum strength are grouped, as shown in Figures 24 and 25, about a point not far from copper 55, zinc = 43, tin = 2. This point is en- circled in the map, Figure 24, by the line marked 65,000 pounds per square inch (4,570 kilogs. per sq. cm.) tenacity, and repre- sented on the model, Figure 25, by the peak of the mountain seen at the farthest side the copper-zinc side. This is the strongest of all bronzes, and an alloy of this composition, if exactly proportioned, well melted, perfectly fluxed, and so poured as to produce sound and pure metallic alloy, with such prompt cooling as shall prevent liquation, is :he strongest bronze that the engineer can make of these netals. The Author finally made this alloy, and of it constructed the model represented in the last figure. It is a close-grained alloy of rich color, fine surface, and takes a good polish. It oxidizes with difficulty, and the surface then takes on a pleas- ant shade of statuary bronze green. The exact composition of this, which the Author has called the " maximum alloy," was not considered as fully determined by this preliminary investigation. The metals used in making it were commercial copper, tin, and zinc, and the methods of mixing, melting, and casting were purposely those usual in the ordinary brass foundry, and necessarily subject to some uncertainty of result. The precise location of this " strongest of the bronzes" was intended to be made in an independent and later research, in which chemically pure metals, more carefully handled, and STRENGTH OF KALCHOIDS. 429 especially well fluxed with phosphorus or other effective flux, should be used. This research was carried out several years later, under the eye of the Author, and an account of it is given later. Testing the alloy above referred to, it was found to have considerable hardness and but moderate ductility, though tough and ductile enough for most purposes ; it would forge if handled skilfully and carefully, and not too long or too highly heated, had immense strength, and seemed unusually well adapted for general use as a working quality of bronze. In composition it is a brass, with a small dose of tin. The alloy made as representing the best for purposes de- manding toughness, as well as strength, contains less tin than the above composition (Cu, 55 ;Sn, 0.5 ;Zn, 44.5). It hacia tenacity of 68,900 pounds per square inch (4,841 kilogs. per sq. cm.) of original section, and 92,136 pounds (6,477 kilogs.) on fractured area, and elongated 47 to 5 1 per cent, with a reduction to from 0.69 to 0.73 of its original diameter. No exaltation of the normal elastic limits was observable during tests made for the purpose of measuring it if noted. This alloy was very homogeneous, two tests by tension giving exactly the same figure, 68,900. The fractured surface was in color pinkish yellow, and was dotted with minute crystals of alloy produced by cooling too slowly. The shavings pro- duced by the turning tool were curled closely, like those of good iron, and were tough and strong. 254. The Strain-Diagrams from the autographic ma- chine (No. 1,001) are shown in fac simile in the accompanying engraving. The tenacity, as estimated from the resistance to torsion, is nearly equal to that determined by direct ex- periment, and four samples tested give strain-diagrams that are all nearly precisely alike. They exhibit an ill-defined elastic limit, e, at about f their ultimate resistance, and about the same as a piece of excellent gun-bronze (Cu, 90; Sn, 10 per cent.), 1,252 A, the strain-diagram of which lies beside them in dotted line. The elastic resilience, which is meas- ured by the area of the curve up to e, is superior to that of the gun-bronze, and the elastic range is seen to be greater, on 43O MATERIALS OF ENGINEERING NON-FERROUS METALS. inspection of the " elasticity lines," e e . In ductility they excel 1,252 A, somewhat, as is seen by comparing 1,001 A with 1,252 A. Their toughness is shown by the great area and the altitude of the curve ; their excellence of quality is also shown by its smoothness of outline. The homogeneous- ness of structure is exhibited by the similarity of the diagrams and by the smoothness of the bend at c, which marks the elastic limit. At /is a depression of the normal line of elastic limits produced by 17 hours intermission of distortion under the load there carried. This slight depression marks this alloy as one of the "tin class." Diagram 1,252 B is given by a fine gun-bronze; 1,001 x is an hypothetical diagram, such as would be produced were the alloy here described so carefully fluxed and cast as Jo exceed in strength the unfluxed alloys actually tested, 1,001 A,B, C, D, in as great a proportion as 1,252 B excels 1,252 A. The dia- gram 1,001 y would be produced were it possible to so far improve this alloy as to cause it to excel 1,252 A as greatly as No. 1,001 actually did excel the gun-bronze made under similar conditions in this preliminary rough work. No. 1,004 A is copied to exhibit the superiority of the alloy 1,001 to one but little removed from it, and which is considered by some brass founders an excellent composition. 255. The Tenacities of the Strong Alloys of copper, tin, and zinc, as obtained by the investigation just described, are, as has been seen, quite variable, and the result of the whole has been fully confirmatory of Major Wade's conclusion rela- tive to useful alloys of copper with softer metals : that they are subject to great variation of quality, as ordinarily made, and that it is impossible to predict with certainty the sound- ness, the uniformity, and homogeneousness, or the strength of any casting in bronze or brass. A study of the figures here obtained, however, and of the map or model exhibiting them, shows that, with good castings of any of the more valuable compositions, certain methods of variation and a general law may be formulated. Thus, for true bronzes containing usual amounts of tin, the tenacity, as such castings are commonly STRENGTH OF KALCHOIDS. 431 432 MATERIALS OF ENGINEERING NON-FERROUS METALS made in the course of every-day business in the foundry, should be about T e = 30,000 + 1,000 /; where t is the percentage of tin, and not above 15 per cent. Thus gun-bronze can be given about 30,000 -f (1,000 x 10) = 40,000 pounds per square inch, if well made. In metric measures T* = 2,109 + 70.3 A giving for good gun-metal 2,109 x 73 = 2 >8i2 kilogs. per sq. cm. For brass (copper and zinc) the tenacity may be taken as T x = 30,000 + 500 z ; where the zinc is not above 50 per cent.; and T z l = 2,109 + 35-15 * Thus copper 70, zinc 30, should have a strength of 30,000 + (500 x 30) = 45,000 pounds per square inch, or 2,109 -f (35- 1 5 x 3) = 3^65 kilogrammes per square centimetre. Referring once more to Figures 24 and 25, it is seen that a line of maximum elevation crosses the field marking the crest of the mountain in Figure 25, of which the " maximum bronze " is the peak. This line of valuable alloys may be practically covered by the formula : M z -f 3 / = Constant = 55, in which z is the percentage of zinc, and t that of tin. Thus a maximum is found at about / = o, z = 55, while the other end of the line is z = o, t = 18. STRENGTH OF KALCHOIDS. 433 Along this line the strength of any alloy should be at least T m = 40,000 + 500 *. T m *= 2,812 f 35-15 ^ Thus the alloy z i, t = 18 will also contain copper = 100 19 81, and this alloy Cu, 81 ; Zn, I ; Sn, 18, should have a tenacity of at least T m 40,000 + (500 x i) = 40,500 Ibs. per sq. in. T* m = 2,812 + (35.15 x i) = 2,847 kilogs. per sq. cm. The alloy Cu, 60; Zn, 5 ; Sn, 16, should have at least the strength T m = 40,000 + (500 x 5) = 42,500 Ibs. per sq. in. T l m = 2,812 + (35.15 x 5) = 2,988 kilogs. per sq. cm. while the alloy Zn, 50 ; Sn, 2 ; Cu, 48, should give, as a mini- mum per specification : T m 40,000 + (500 x 50) = 65,000 Ibs. per sq. in. T l m = 2,812 + (35.15 x 50) = 4,570 kilogs. per sq. cm. These are rough working formulas that, while often de- parted from in fact, and while purely empirical, may prove of some value in framing specifications. The formula for the value of T m fails with alloys containing less than I per cent, tin, as the strength then rapidly falls to t o. The table which follows will present, in convenient form, probably fair minimum values to be expected when good foundry work can be relied upon, and may ordinarily be used in specifications with the expectation that a good brass-founder will be able to guarantee them. 28 434 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXVIII. MINIMUM TENACITY OF ALLOYS. ALLOY. TENACITY. Probable Minimum. Cu. Zn. Sn. Lbs. per sq. in. Kgs. per sq. cm. IOO 6 o 30,000 2,109 95 5 32,500 2,285 90 10 o 35,ooo 2,460 85 15 o 37,500 2,636 9 IO 40,000 2,812 95 o 5 35,000 2,460 97i o 2* 32,500 2,285 90 5 5 37,500 2,636 85 IO 5 40,000 2,8l2 75 20 5 45,000 3,163 68 30 2 47,000 3,304 64 35 I 48,500 3,410 -60 40 50,000 3,515 256. Ductility. The ductility of these alloys is a subject of as much interest to the engineer as their strength ; and in this quality the ternary alloys are as variable as in every other. Referring again to the map, Figure 26, it is seen that a closely grouped set of slightly curved and slowly converging lines cross it from tin = 25, to zinc 55, the mean line having an equation nearly 2.2/ + z 55. Along this line the alloys have immense tenacity, as exhibited by the fact that some of them, if not nearly all, are too hard to be cut by steel tools, and in shaping them only grinding tools either the emery wheel or the grindstone could be used, and even then with most unsatisfactory results. Yet such was the brittleness of these metals that no reliable test of their strength could be obtained. The strain-diagrams obtained were straight, and nearly vertical lines, terminating suddenly, when the piece snapped, without indication of approach to an elastic limit. They were perfectly elastic up to the point of fracture, but were so destitute of resilience that no use can probably be made of them by the engineer. Their brittleness was such that they would often break in the mould by contraction in STRENGTH OF KALCHOIDS. 435 cooling, although cast in a straight bar. In some cases they crack by the heat of the hand, and were broken at one end by the jar transmitted from a light blow struck at the other end.* The border line of this valueless territory is shown FIG. 27. DUCTILITY OF COPPER-TIN-ZINC ALLOYS. on the map by a slightly curved dotted line to which a line having the equation 2.5/ -f s = 55 is nearly tangent. The alloys lying along this line have nearly equal ductility, ex. tending, according to measurements obtained by the auto, graphic machine, about .03 of one per cent. * Report to U. S. Board. Figure from the R.R. Gazette. 43 6 MATERIALS OF ENGINEERING NON-FERROUS METALS. Above this line is another having nearly the equation 4^ + 2 = 50, which last line is that of equal ductility for alloys exhibiting extensions of 3 per cent. Still nearer the "pure copper corner" is a line fairly representing alloys containing about 33^ + z 48, and along which the extensions were 7.3 per cent., and another such line extending from standard gun- metal compositions on the one side to Muntz metal on the other Cu 90, Sn 10, to Cu 55, Zn 45, of which the equa- tion is nearly 4.5^ + s = 45, represents alloys averaging an extension of 17 per cent. These lines are best seen on the sheet of extensions, Fig. 28. All alloys lying above the line taken here as a boundary line give figures for tenacity that ex- ceed 30,000 pounds per square inch (2,109 kilogs. per sq. cm.). The addition of tin and of zinc to cast copper thus in- creases tenacity at least up to a limit marked by the line 3^ + 2= 55 ; but the influence of tin is nearly twice as great as that of zinc, and the limit of useful effect is not reached in the latter case until the amount added becomes very much greater than with the former class the copper-tin alloys. Brasses can be obtained which are stronger than any bronzes, and the ductility of the working compositions of the former class generally greatly exceeds that of the latter. Ternary alloys may be made containing about 4? + z = 50, which ex- ceed in strength any of the binary alloys, and compositions approaching copper, 55; tin, 2; zinc, 43; may be made, of extraordinary value for purposes demanding great strength, combined with the peculiar advantages offered by brass or bronze. The addition of one-half per cent, tin to Muntz metal confers vastly increased strength. The range of useful introduction of tin is thus very much more restricted than that of zinc; alloys containing 12 to 15 per cent, tin are so hard and brittle as to but rarely find ap- plication in the arts, while brass containing 40 per cent, zinc, is the toughest and most generally useful of all the copper zinc " mixtures." The moduli of elasticity of these alloys are remarkably uniform, more than one-half of all those here described ranging closely up to fourteen millions, or one-half that of well-made steel-wire. The moduli gradually and STRENGTH OF KALCHOIDS. 437 slowly increase from the beginning of the test to the elastic limit. The Fracture of these Alloys is always illustrative of their special characteristics. Those broken by torsion in the autographic testing machine were, if brittle, all more or less conoidal at the break ; ductile alloys yield by shearing in a plane at right angles to the axis of the test piece ; the for- mer resemble cast iron and the latter have the fracture of wrought iron. Every shade of gradation in this respect is exhibited by an observable modification of the surface of fracture varying from that characteristic of extreme rigidity and brittleness, through an interesting variety of intermediate and compound forms to that seen in fracture of the most ductile metals. 257. Possibilities of Improvement. The tenacities and ductilities given are within the best attainable figures where they relate to the most valuable working bronzes and brasses. These figures represent the result of ordinary founders' work ; and metals rich in copper, made with no greater precaution against oxidation and liquation than is usual in brass foun- dries, may be vastly improved by special treatment sug- gested, by using pure ingot metals, fluxing carefully, as with phosphorus or manganese, casting in chills, rapid cool- ing, and finally rolling, or otherwise compressing, either hot or cold. Unannealed copper wire is ^reported by Baudrimont* as having a tenacity of about 45,000 pounds per square inch (3,163 kilogs. per sq. cm.), and Kirkaldy reports 28.2 tons per square inch (63,168 pounds per square inch, 4,440 kilogs. per square cm.), the wires having diameters of 0.0177 and 0.064 inches (0.044 an d 0.165 cm.) respectively. A way should be found to secure equal purity, homo- geneousness, and density in cast copper, and such metal should then possess tenacity and toughness equal to that of rolled metal. Gun-bronze, which ordinarily has a tenacity of about 35,000 pounds per square inch (2,460 kilogs. per sq, cm.) has been made at the Washington Navy Yard, by skil- * Annales de Chiinie, 1850. OF THE ^ >v {UNIVERSITY) 43 8 MATERIALS OF ENGINEERING NON-FERROUS METALS. ful mixture, melting and pouring, and by the Author, also, to attain a tenacity of above 60,000 pounds (4,218 kilogs.). The effect of thorough fluxing with deoxidizing sub- stances is so important that no founder can safely neglect it. FIG 28. DUCTILITY OF COPPER-TIN-ZINC ALLOYS. COPPER Bronzes fluxed with phosphorus, arsenic, and manganese, have been given fifty per cent, higher tenacity than the or- dinary unfluxed alloy, and the addition of a little iron, as in the so-called " sterro-metal " of the Baron de Rosthorn, and in Parson's " Manganese Bronze," has still further strengthened the copper-tin-zinc alloys. Dr. Anderson made experiments at Woolwich, showing STRENGTH OF KALCHOIDS. 439 an increase of strength of sterro-metal, by forging, to the extent of 25 per cent., and by drawing cold of 40 per cent. Brass, containing copper, 62 to 70, zinc, 38 to 30, attains a strength in the wire mill of 90,000 pounds per square inch, and sometimes of 100,000 (6,327 to 7,030 kilogs. per sq. cm.), and these alloys should be made equally tenacious in the casting. The Author has no doubt that the methods indicated as those best adapted to secure dense, strong and tough metal will yet be found capable of yielding alloys of more than double the strength representative of what is now ordinary brass- founders' work. It should be possible to secure copper-tin- zinc alloys having tenacities represented by : ' T mm = 60,000 + I ,ooo/ + 500 z, T I mm =4,218 +- 70.3^ + 35-15^ throughout that area on the map representing the most use- ful alloys, from copper, 100, to 4/ + z = 50. Manufacturers of special bronzes are approaching this de- gree of excellence. In the working of copper in the foundry the melter meets with difficulty from the formation of either the oxide or car- bide. Could he secure immunity from combination with one or the other of these elements, he would find innumerable uses for cast copper. The general character and the method of variation of strength and ductility of the alloys of copper, tin, and zinc are so well exhibited by the illustrations presented, that no difficulty will be met with by the engineer in the endeavor to select the alloy best adapted to any specific purpose where such an adaptation is determined by physical qualities alone. Caution must be used in selecting alloys where great strength is demanded, since a slight change of composition by the ad- dition of tin or zinc may make a serious change in the direc- tion of lessened ductility and toughness. The engineer will rarely use those lying on the tin and zinc side of the line of alloys having 0.07 (7 per cent.) ductility, as on Figs. 27 and 28. Extraordinary care must be taken in making the strongest alloys. 44 MATERIALS OF ENGINEERING NON-FERROUS METALS. Alloys to be hammered or rolled will be found more diffi- cult to work as the percentage of tin is increased, and the minutest addition of tin to the brasses usually rolled is found to sensibly decrease their manageability. 258. The "Maximum Bronzes" form a group demand- ing special consideration as including a collection of generally unfamiliar but exceptionally valuable alloys. The work planned by the Author in the investigation of this part of the subject was left incomplete by the U. S. Board, but was continued, as opportunity offered, at intervals up to the year 1884.* The position and characteristics of the strongest possible alloys of the three metals constituting the "Kalchoids" having been determined with a fair degree of accuracy, as al- ready described, the next step was to ascertain what modifi- cations might be produced in them by careful fluxing and the use of still more carefully prepared alloys. This later study was made in the years 1882-3, in the same manner as the earlier investigations for the U. S. Government, at the sug- gestion and under the supervision of the Author, by Mr. W. E. H. Jobbins, whose report is here abridged. f The area chosen as the field of this investigation was a small triangular portion surrounding the peak of the moun- tain, Fig. 25, marked 65,000 on Fig. 24, as this area embraces all that portion of the field in which the most valuable alloys had been proven to be located. The data obtained gave ex- ceedingly high figures, the lowest average value of tenacity being above 50,000 pounds per square inch (3,515 kilogs. per sq. cm.)- As this research extended over a very limited area, it was possible to conduct the investigation with much greater exactness than before, and thus settle the composition of the " strongest of the bronzes." The metals varied with differences of but one per cent.; 23 combinations were chosen ; 2 test-pieces were made of each * The U. S. Board was strangled by refusal of appropriations, leaving the work in hand unfinished. Some of the work necessary to the presentation of the reports actually made was, however, concluded by the Author, at some expense, in the Mechanical Laboratory of the Stevens Institute of Technology. f " Investigation Locating the Strongest of the Bronzes," J. F. I., 1884. STRENGTH OF KALCHOIDS. 441 composition, making 46 test-pieces. Usually, the data obtained from two specimens of the same composition agreed so closely that the average value was safely taken ; but, when there was a marked difference, the data agreeing more closely with the results anticipated from analogy were adopted, and the other value rejected as being probably erroneous. The copper em- ployed was from Lake Superior, the zinc from Bergen Port. In the use of tin, phosphorus was added to give soundness in these copper-tin and copper-tin-zinc alloys, which are so liable to be made seriously defective by the absorption of oxy- gen and the formation of oxide. It has been found possible to produce, on a commercial scale, an alloy of phosphorus and tin, which, while containing a maximum percentage, does not lose phosphorus when remelted. The best proportions for practical purposes are said to be tin 95 per cent, and phos- phorus 5 per cent. After careful study, the following limits of the field were decided upon: Copper, maximum 60, minimum 50; Zn, 48 and 38 ; Sn, 5 and o. These limits include the best alloys for purposes demanding toughness as well as strength. The compositions are given in the following table : TABLE LXXIX. BEST COPPER-TIN-ZINC ALLOYS, OR KALCHOIDS. NO. cu. ZN. SN. NO. cu. -N. SN. NO. CU. ZN. SN. I 55 43 2 9 53 43 4 17 58 40 2 2 54 44 2 IO 55 4i 4 18 54 45 I 3 54 43 3 II 57 4i 2 19 53 44 3 4 55 42 3 12 57 43 20 54 42 4 5 56 42 2 13 55 45 O 21 5<> 41 3 6 56 43 I 14 52 46 2 22 57 42 i 7 55 44 I 15 52 43 5 23 5 41 I 8 53 45 2 16 55 40 5 The castings were made much as in all the earlier investi- gations, the same precaution being taken to prevent volatili- zation of zinc, and care was taken to secure rapid cooling to prevent liquation. All the compositions thus made were 44 2 MATERIALS OF ENGINEERING NON-FERROUS METALS. strong and usually tough ; all could be turned and worked safely, and all were evidently of commercial value for the pur- poses of the engineer. All test-pieces were sound, and even microscopic examination revealed no defects in structure. The investigation was made by the use of the Author's auto- graphic machine as permitting most rapid work and most ex- act determinations of quality and behavior, especially as to the latter near the elastic limit. The samples were all re- duced to the standard form and size. 259. Results of Tests. The formula used is M wJi + /; where w = moment necessary to deflect the pencil one inch ; h = height of the curve above the base line al. r , f = friction in foot-pounds, and M is the total torsional moment. In this case, w 96.93 foot-pounds, and/"= 4.75, h being measured on the strain-diagram of each test-piece. To obtain the required values of T the formula T [300 J^#J M* in which M is known, and d r is measured directly from the autographic record ; T is the calculated tenacity. The values of M, T, B e and r , the total moment, the approximate tenacity, and the angles of torsion at the elastic limit and at rupture, have been included in the following table : TABLE LXXX. STRENGTH OF BEST COPPER-TIN-ZINC ALLOYS OR KALCHOIDS. | ORIGINAL STRESS IN TORSION. FOOT-POUNDS. M. APPROXIMATE STRESS IN TENSION. FOOT-POUNDS. ANGLES. MARK. " Ultimate. Average. Ultimate. Average. Oe 0,- IXI A 270.208 251.922 261.065 77,309 72,301 74,805 5 43 40 OB A 178.321 208 . 400 193.369 53,946 59,810 56,653 . i 0.7 5-05 40 Z3 A 251.922 219 935 235-929 75,576 65,980 70,778 13-77 10 J4 * 243.392 258.319 250. 851 73,oi7 74,9*2 73,965 2 2 19.8 30-3 * This relation between torsional and tensional resistances was obtained by experiment on the machine used in this investigation. Trans. Am. Soc. C. E., no. clxiii., vol. vii., 1878. STRENGTH OF KALCHOIDS. TABLE LXXX. Continued. 443 ORIGINAL MARK. STRESS IN TORSION. FOOT-POUNDS. M. APPROXIMATE STRESS IN TENSION. FOOT-POUNDS. T. ANGLES. Ultimate. Average. Ultimate. Average. o e Qr *' 268.881 263.543 266.212 75,824 75,109 75,467 4.6 2 55 46 06 A 227.689 220.612 224.151 64,208 63,193 63,700 2.05 53.3 2 i 42.1 K7 ' A 286.847 250-855 268.851 80,910 70, 741 75,826 2 2 54 53 RS A 194.634 I84-3JI 189.488 58,390 55,299 56,844 2 2.69 9.1 5 72 5 222.853 230.597 226.725 66,853 69,179 68,017 1-5 1.79 5-78 4-5 Lio * 249.014 252.881 250.948 74,704 75,864 75,284 2.1 2.8 4.6 8.8 Zl! * 260 . 645 237.382 249.014 74,269 63,964 69,116 2.4 1.9 39-8 35 DB * 227.689 241.259 234-474 61,020 61,762 61,390 2-3 1.6 95-2 I3I-4 M 13 * 227.689 20S . 303 217.996 64,208 57,908 61,058 2 I.I 52-4 65 UI 4 163.715 177.185 170.^50 49, "3 53,155 51,139 2-3 2 4-9 7-2 V. S 189.886 227.689 208.788 56,965 68.306 62,636 2.6 2 4 5 Ni6 * 225.750 253.198 239-974 67,725 75,959 71,842 '* 3.8 6.8 A 17 A 227.689 250.952 238.771 68,344 '\ 73,4" - 54 43-2 Pi8 A 254.829 260.645 259-737 72,871 .71,501 72,186 ;J 43 4 54 T, 9 A 231.566 196.671 214. 119 69,459 59,001 64,230 .4 8 4.8 QBO A 229.628 258.707 244.168 68,888 77,612 73,250 .6 .8 6.4 7-2 HBI A 283 . 908 229 628 266.768 81,381 68,888 75,13? 2-9 2.4 1 EBB A 305-233 221.773 263 . 508 85,770 60,986 73,378 2 56 2.5 76 B33 225.750 175.247 200.499 63,084 45,038 54,061 i 6 , 63 1.2 ! 128 The neck subjected to distortion is in all cases, one inch (2.54 cm.) long between shoulders and ^ inch (1.5875 cm.) in diameter. 260. Discussion. It proved, notwithstanding the pre- 444 MATERIALS OF ENGINEERING NON-FERROUS METALS, cautions taken in making these alloys, to be a matter of some difficulty to decide satisfactorily the relative positions of the alloys studied. Nos. 7 and 22 were the best alloys made. No. 7 was a fine grained alloy, with a smooth, even fract- ure, tough fibrous appearance, and twisted apart slowly and evenly. No. 22 was an alloy, golden in color, very close grained and with a fracture in all respects similar to No. 7, and exceedingly tough. It was found that, when the average values of J/and T were used, No. 7 stood first upon the list, while, when the higher values were taken, No. 22 was first. In the case of No. 22 there was a difference in the values which indicated a change in composition either from volatili- zation or from some other cause. No. 22 must be considered the strongest alloy. The third upon the list is No. 21. It exhibited con- siderable liquation. The metal was of a bright straw color and had a smooth, regular fracture and considerable ductility. No. 5 was fourth and No. I fifth. No. 5 was a very fine- grained alloy, possessing great ductility and a smooth, square fracture and very close and compact grain. Higher results can undoubtedly be obtained from an alloy of this composi- tion ; these specimens showed signs of slight liquation. No. i was a tough metal, the pieces being twisted apart slowly, snapping suddenly, as in the previous case ; better results should be expected from this alloy ; it exhibited signs of an imperfect mixture of the metals. This was the strongest alloy reported by the Author previously. The sixth position was assigned to No. 11, which exhibited a fine regular fract- ure and high ductility ; it twisted apart slowly and evenly. No. 1 8 was a good alloy, and although more crystalline than those previously mentioned, had a smooth fracture and high moduli ; it was very ductile. The eighth upon the list, No. 10, was a very brittle alloy ; its values for B r being but 4.6 and 8.8 ; its color was gray, with a fracture closely resembling steel. Its tenacity was 75,000 pounds per square inch (5,272 kilogs. per sq. cm.), a higher figure than some of the preced- ing alloys have given ; it was very hard. No. 4 stands ninth. There was considerable liquation ; while it exhibited a smooth STRENGTH OF KALCHOIDS. 445 and regular fracture and broke off slowly and evenly. It was light yellow in color. Its upper end was granular and uneven in fracture ; it was of a very light gray color, indi- cating a brittle metal, but it was quite strong and ductile. This alloy contained I per cent, more zinc and I per cent, less tin than No. 10, and, though having slightly less strength, it was far more ductile. The next best alloy, No. 20, an alloy very bright in color, almost white, and having a ragged fract- ure, was an exceedingly brittle alloy, its average value for B r being but 6.8 ; its tenacity was very good. The eleventh, No. 1 6, was a remarkably dense alloy, very hard, with a fract- ure closely resembling steel. Its strength was very great. No. 3, the twelfth on the list, was less brittle than the pre- ceding, its average value of O r being 1 1.9. While testing the A end a " set " took place. It broke suddenly, giving a very ragged, granular fracture ; it was light in color. Thirteenth, No. 17, was a very ductile alloy, its values for 6 r averaging 48.6. It was of a deep golden color, and had a smooth, regular fracture. Fourteenth, No. 19, was close-grained, brittle, nearly white in color, and gave a very ragged and uneven fracture ; it broke suddenly. Fifteenth, No. 9, was another very brittle alloy, with a fracture closely resembling steel. Sixteenth, No. 6, was very ductile, giving a smooth, regular fracture. Its values of tenacity were good. Seven- teenth, No. 12, was not a triple alloy, as it contained copper and zinc only. It was an exceedingly beautiful alloy, of a deep golden color and very closely grained. This was, by far, the most ductile alloy tested, the average of B r being 1133. Eighteenth, No. 23, was the second most ductile alloy. This alloy had a fine fracture, smooth and regular. In color, it very closely resembled green bronze. Nineteenth, No. 13, was also a binary alloy, and though resembling No. 12 in appearance its ductility was only about one-half that of No. 12. Twentieth, No. 15, was exceedingly brittle, and closely resembled steel in fracture. Twenty-first, No. 2, was surrounded by alloys which gave much better results, and therefore a weak specimen ; this was not looked for in this place. It was ductile and had a good, even fracture ; it 44-6 MATERIALS OF ENGINEERING NON-FERROUS METALS. resembled No. 23 in color. Twenty-second and twenty- third, Nos. 8 and 14, both contained large amounts of zinc and little copper, and consequently were both brittle and weak. FIG. 29. STRONGEST OF BRONZES. 261. Conclusions. The Strongest Bronzes. The results obtained from this investigation are well exhibited in the ac- panying diagram, Fig. 29. It was concluded that the alloy numbered 22 was what the Author has called the " strongest of the bronzes/' and that its composition (Cu, 57; Sn, I ; Zn, 42) should locate the peak seen in the model, Fig. 25, and on the map, Fig. 24. No. 5, however (Cu, 56 ; Sn, 2 ; Zn, 42), is likely to prove a more generally useful alloy in consequence STRENGTH OF KALCHOIDS. 447 of its greater ductility and resilience ; and alloys with a little less tin may often prove even better than that. The Author has called the compositions, copper, 58 to 54; tin, y 2 to 2^ ; zinc, 44 to 40, which may be considered as representative of a group having peculiar value to the engineer, the "maximum bronzes." This cluster lies immediately around the peak seen on the model, Fig. 25, including the point of maximum alti- tude. The safest alloys under shock are those containing the smallest quantities of tin. 262. The Conclusions reached after concluding the in- vestigations which have been described in the present chap- ter are confirmed by the fact that a number of single compo- sitions have been independently discovered by other experi- menters, accidentally or incidentally to special investigations, which have peculiarly high tenacity, all of which approximate more or less closely, in their proportions, to these " maximum " bronzes and strongest " Kalchoids." Thus, Mr. Farquharson, president of the Naval (British) Commission, proposed, in 1874, an alloy composed of 62 parts of copper, 37 parts of zinc, and one part of tin. This is the reglementary naval alloy. When cast in bars it has shown on test a resistance of 70,000 pounds per square inch (5,000 kilogs. per sq. cm.). It rolls and works well, can be hammered into sheets, and is fusible only above red heat. It may be used as a lining for engine-pumps. It is but slightly oxidiz- able, and is not sensibly attacked by sea water, as shown by experiments with it extending over a period of years. A slight loss of zinc during melting must be taken into account. The British naval bronze for screw-propellers, stern bearings, bow- castings, and similar work, is composed of copper, 87.65 ; tin, 8.32 ; zinc, 4.03, and is reported to have a tenacity of 15 tons per square inch (2,362 kilogs. per sq. cm.), and to average 13^ tons (2,126 kilogs.) in good castings. Tobin's alloy, al- ready described, is one of the " maximum " bronzes, also, containing copper, 58.22 ; tin, 2.30; zinc, 39.48. Sterro-metal is always a brass of nearly the same proportions of copper and zinc, i.e. t a Muntz metal, containing from a fraction of I per cent, to sometimes 2 per cent, of tin, as well as some iron. 448 MATERIALS OF ENGINEERING NON-FERROUS METALS. The bronze used for journal bearings in the U". S. Navy contains copper, 88 ; tin, 10 ; zinc, 2. The strongest U. S. copper-tin-zinc alloy is that discovered by Mr. Tobin and described by the Author in earlier articles, and, as has been stated, had a tenacity of 66,500 pounds per square inch of origi- nal section, and 71, 378 per square inch of fractured area(4,575 and 5,019 kilogrammes per sq. cm.) at one end of the bar, which was, as usual, cast on end, and 2 per cent, more at the other. This, like the " maximum alloy," was capable of being forged or rolled at a low red heat or worked cold. Rolled hot, its tenacity was 79,000 pounds (5,553 kilogs. per sq. cm.), and when cold-rolled, 104,000 (7,311 kilogs.). It could be bent double either hot or cold, and was found to make excellent bolts and nuts. These and other compositions which have been occasion- ally introduced as having extraordinary strength and excep- tional value, all contain a small amount of tin, and invariably fall within the field mapped out as described in this chapter as that containing the kalchoids of maximum possible strength. The latter, the " maximum alloys," as the Author has called them, will probably be very generally, if not exclusively, used when alloys are required of peculiar strength. CHAPTER XII. STRENGTH OF ZINC-TIN AND OTHER ALLOYS. 263. The Zinc-Tin Alloys form the third bounding line of the system of copper-tin-zinc alloys which have been stud- ied, as the copper-tin and copper-zinc compounds form the two sides first examined. Within the field represented on the map, Art. 252, page 425, and on the tin-zinc side of the depression which lies parallel with the crest of maximum strength, are also a set of ternary alloys characteristically different from those which have been the object of specia. investigation. These are the gray and the white alloys of copper, tin, and zinc, which have no use in the work of the engineer except for bearing metals and as solders. The char- acteristics and uses of these alloys are so similar to those of the tin-zinc alloys that they are here classed and treated of together. The zinc-tin alloys are usually easily made, and are sound and dense and uniform in quality and structure. They are soft, weak, smooth of texture, as a rule, and readily alloy with the surface coating of tin-plate and with zinc; they thus make good "soft solders " as well as good metals with which to line the bearings of heavy journals in heavy machinery. Common solders are elsewhere described. Among them are " yellow solder," composed of equal percentages of copper and zinc, with one part tin either added or substituted for two or three per cent, zinc ; " black solder," composed of 30 copper, 45 zinc, and tin, 25 ; these fall among the stronger alloys out- side the gray mixtures. No tests of the tin-zinc alloys were made in the research described in the preceding chapter, but the study of the model, Fig. 25, page 427, gives the value of this set of com- pounds as satisfactorily as if they had all been directly inves- tigated. 29 450 MATERIALS OF ENGINEERING NON-FERROUS METALS. 264. The Strength of Tin-Zinc Alloys is seen to vary very smoothly and uniformly from the pure zinc to the pure tin end of the series. It may, therefore, be assumed as sub- stantially true that the strength of the tin-zinc alloys is the mean of that of their constituents. This is also practically true of their other physical and mechanical properties. Hence, the tenacity of good alloys of this class should be expected to be not far from T = 4,500 ^ + ,,, , 6 + 492 in British and metric measures, respectively, where t and z represent the proportion of each metal in unity of weight. The Resistance to Compression is, for tin-zinc alloys, fairly taken as below, for ten per cent, compression, C 6,000 t + 20,000 z 9 \ , . C m - 422 t + 1,406 z, f The Modulus of Rupture maybe taken for tin-zinc com- positions, at R = 3,500* + 7,500*,) R m = 246 / + 527 z, f and the Modulus of Elasticity at 7,000,000 British, 492,000 metric for all. The Specific Gravity is fairly reckoned at 5. G. = 7-3 t + 7.15* ..... .... (19) 265. The Gray Alloys of copper, tin, and zinc are more uniformly modified by the addition of copper to the tin-zinc compounds than are the yellow and stronger alloys. Those containing little zinc are very irregular in strength, but, on the whole, weaker than those containing little tin, and are generally but little stronger than the latter metal. These cop- per-tin-zinc alloys, rich in zinc and poor in tin, are strongest where the compositions contain between copper, 15 or 20, zinc, 85 or 80, and are weakened quite uniformly by the ad- dition of tin, and by either the increase or diminution of the STRENGTH OF ZINC-TIN ALLOYS. 45 1 proportion of zinc, the tensile strength becoming insignificant when the proportions are such that, approximately, z 4- 2 / =: 90 per cent., along which line lie the alloys of maximum hardness and brittleness. The tenacity of this group of alloys usually ranges be- tween 3,000 and 5,000 pounds per square inch, sometimes reaching 10,000 (211, 351, 703 kilogs. per sq. cm., respectively); the resistance to compression is not known ; the modulus of rupture falls, usually, not far from 5,000 pounds per square inch, rising to above 10,000 (352 and 703 kilogs. per sq. cm.), and as often falling below the smaller figure. The modulus of elasticity is generally about 12,000,000 (844,000 metric), although with the softer alloys it falls to one-half that amount. 266. Earlier Investigations of these alloys have been of little value in determining their properties. An alloy of tin, 80; zinc, 20, is said, by earlier writers, to have a tenacity of 10,000 pounds per square inch (703 kilogs. per sq. cm.), or double that estimated as above. The alloy, zinc, 77; tin, 14; copper, 14; antimony, 3; lead, I, which falls into the class here . considered, very nearly, is Burton's alloy for plough- shares. Magee's, for the same purpose, is copper, 85 ; tin, 12 ; zinc, 3. Zinc, 20 ; tin, 20, is Brayton's alloy for eyelets. Stru- bing's anti-friction metal is composed of zinc, 75; tin, 18; lead, 4^2 ; antimony, 2^. The alloy composed of equal parts tin and zinc is said by Laboulaye to be remarkably durable under wear, and to have nearly the strength of brass, a state- ment which is not confirmed by the investigations here de- scribed and requires confirmation. The strength of many of these alloys has never been determined. An "anti-friction metal," of 'unknown composition, tested by the Author, had a tenacity of 11,100 pounds per square inch (773 kilogs. per sq. cm.), and broke without stretching. An alloy of gold, 14; silver, 10, with a trace of copper, is often made into wire to replace brass, and is found to have about the same strength. 45 2 MATERIALS OF ENGINEERING NON-FERROUS METALS. Various alloys examined by Muschenbroek,* who was the only physicist, or engineer, who had given much time to the study of the mechanical properties of alloys until a very recent period, were found to have tenacities as given in the following table to the nearest thousand. TABLE LXXXI. TENACITY AND DENSITY OF VARIOUS ALLOYS. ALLOYS. TENACITY. S. G. Lbs. per sq. in. Kilogs. per sq. cm. Gold, 66.7; Silver, 33.3 28,000 1,968 83.3; Copper, 16.7 50,000 3,515 . . . Silver, 83.3; " 16.7.... 49,000 3,445 . . . 80.0; Tin, 20.0 41,000 2,882 . . . Ti n (Eng.), 90.9; Lead, 9.1 7,000 492 ... 1 ' 88.9; ii. i 8,000 562 . . . 1 85.7; I4-3-..- 8,000 562 ... 1 4 80.0; 20. o. . . . II,OOO 773 . . . * * 66.7; 33.3. ... 7,000 492 4 ' 50.0; 50.0 7,000 492 T n (B nca), 90.9; Antimony, Q.I.... 11,000 773 7*36 * 88.9; ii. i 10,000 703 7.28 * 85.7; 14.3..-. 13,000 914 7-23 * 80.0; 20. o. . . . 13,000 914 7.19 ' 66.7; 33-3-. 12,000 . 874 7.II * 50.0; 50.0 3,OOO 211 7.06 T n(B nca), 90.9; Bism uth, 9.1 13,000 914 7-58 ' 80.0; 20. o. . . . 8,000 562 7 .6l ' 66 7; 33-o.... 14,000 984 8.08 * 50.0; 50.0 12,000 844 8.15 < 33-3; 66.7.... 10,000 703 8.58 * 20 o; 80.0 8,000 562 9.01 ' Q.I; 90.9.... 4,000 281 9.44 L ad, 50.0; Bisrr uth, 50.0. . . . 7,000 492 10.93 66.7; 33-3.... 6,000 422 11.09 9.1; 90.9.... 3,000 211 10.83 267. The Records of Experiments upon the copper-tin- zinc alloys which follow are selected from those reported by the Author to the Committee on Alloys of the U. S. Board as representative of the more successful mixtures. These alloys have been already described at some length, and further * Introd. ad Phil. Nat.; Phil. Ma^., 1817, Vol. L.; Tredgold. STRENG TH OF COPPER-ZINC- TIN ALLO VS. 45 3 description in detail is here unnecessary.* Although selected examples, some considerable part of the variation observed among them is probably due to the varying conditions met with in ordinary foundry work; the principal cause of these great differences of strength and ductility is, however, to be attributed to differences in composition. It will be observed that the strongest of these alloys are not distinguished by great ductility, a fact already frequently illustrated in earlier portions of this work. Examining the records of test by tension, it is seen that the better class of alloys exhibit a great regularity of elonga- tion under increasing loads. Comparing the tenacities of the best specimens with the moduli of rupture, it is seen that the latter exceed the former by about fifty per cent. In ductile metals the resistances to compression and to extension do not greatly differ where, as in a bent bar of the proportions here adopted, the compressed metal is not confined. The modulus of rupture for a beam of rectangular section when the material is elastic and brittle is that given in the common theory of resistance of materials, R = -T~TJ, in which M, b, d, are the bending moment, the breadth and the depth of the bar. When the material is ductile, R^ = ^r, and, there- oa* fore, R = | Rj when the bar is of the same dimensions and the same bending moment is attained at rupture, assuming the same theory applied to each case and the apparent mod- ulus to be accepted.f In the cases of some of the valuable alloys of which the records of test are here given, the moduli of rupture are often in excess of the tenacities by fifty per cent., or in the same proportion as in wrought iron,J proving them to belong to the class to which the second of the expressions just given be- longs. This is best illustrated by bar No. 12 (copper, 58.22 ; tin, 2.30; zinc, 39.48). * Vide Report of the U. S. Board, Vol. II., Washington, 1881. f Part II., p. 487, 263, Eq. (113). J Part II., p. 491. 454 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXII. TESTS BY TENSILE STRESS. ALLOYS OF COPPER, TIN, AND ZINC. DIMENSIONS. Length = 5" (12.7 cm.); diameter = .798" (2 cm.). BAR NO. I B-D. COMPOSITION. Original mixture : Cu, 70 ; Sn, 8.75 ; Zn, 20.25. K tt M gg H C Sa 1- . H Z O 1 - -1 M O SET. 11 5 i SET. l3 S o S 2 P < Q z O (4 Q o O f-' 3 3 a P 3 3 a Z z 3 " Pounds. /wA. Inch. Pounds. Inch. Inch. 1,400 .OO3I .002 16,000 .0046 .092 i, 600 .0001 .OO2 18,000 .0052 .104 i, 800 .0002 .004 20,COO .006! .122 2,000 .0002 .004 3~o .0001 .OO2 2,500 .0003 .006 10,000 .0010 .020 3,000 .0004 .008 20,000 .0053 . . . . .106 3i5 .0005 .010 22,OOO .0064 .. .. .128 4,000 .0007 .014 24,000 .0084 . . .168 5,000 .0009 .018 28,OOO .0142 .28 4 6,000 .0012 .024 32,000 .0217 434 7,000 .0014 .028 36,000 .0316 . . . . .632 8,000 .00l6 .032 Broke. 9,000 10,000 11,000 12,000 13,000 .OO22 .0024 .0028 .0031 0035 .044 .048 .056 .062 .070 Tenacity per square inch, original section, 36,000 pounds (2,531 kilogs. per sq. cm.). Tenacity per square inch, fractured section, 36,080 pounds (2,536 kilogs. per sq. cm.). Diameter of fractured section, 0.797" (2 cm.). 14,000 .0038 .076 BAR NO. 5 B-D. COMPOSITION. Original mixture: Cu, 88.135 5 Sn, 1.865 ; Zn, i< 3,200 .0014 -035 7,000 .0040 .100 4,000 .0018 -045 8,000 .0042 .105 4.500 .0020 .050 9,000 .0044 . no 5,000 5,5o .0023 .0026 ::::: .057 .065 10,000 11,000 .0050 .0054 125 .135 6,000 .0028 .070 12,000 .0058 .145 7,000 8,000 .0033 .0036 .082 .090 13,000 14,000 .0088 .0121 .220 -302 9,000 .0039 .097 15,000 .0161 .402 10,000 .0043 .107 16,000 .0252 .630 11,000 .0047 .117 18,000 .0548 I -37 12,000 .0052 .130 20,000 .0987 2.460 300 .0008 22,000 *5<)5 3-987 100 .OOII .027 26,000 .3118 7-795 1,400 .0013 .032 30,000 5177 12.942 1, 800 .0015 .037 33,000 .7818 19-545 2,200 .0017 .042 Broke. 2,600 3,000 4,000 5,000 0,000 .0019 .0022 .0028 .0033 .0037 .047 055 .070 .082 .092 Tenacity per square inch, original section, 33,000 pounds (21.30 kgs. per sq. cm.). Tenacity per square inch, fractured section, 47,649 pounds (33.52 kgs. per sq. cm.). Diameter of fractured section, 0.664" U-7 cm.). STRENGTH OF COPPER-ZINC-TIN ALLOYS. 455 TABLE LXXXII. Continual. BAR NO. 7 B-D. COMPOSITION. Original mixture: Cu, 66.885; Sn, 1.865; Zn, 31.25. 2 fc H 2 h - O - O D D . C* 2* 2 t~ O 1 Jr 2 ^"* K 5 i SET. ggg 5 p SET. - P a a. s g 2 O ^ O z D 2 3 -" a _I M 1 r Pounds. Inch. Inch. Pounds. Inch. Inch. 300 .... 6,000 .0029 .058 1,000 .0002 .004 8,000 0033 .066 2,000 .0004 .008 10,000 .6042 .084 3,000 .0006 .OI2 12,000 0055 .110 4,000 .0008 .Ol6 14,000 .0069 ..... .138 4,200 .0008 .Ol6 l6,OOO .0089 .178 4,400 .0009 .018 l8,000 .0113 .226 4,600 5,000 .0010 .0011 :::.: .020 .022 2O,OOO 22,000 .0209 .0309 .418 .618 5,400 .0012 .024 24,000 .0444 .888 6,000 .0013 .026 26,000 .0589 1.178 7,000 .0015 .030 28,000 .0779 1.558 8,000 .0017 .054 30,000 .1019 2.038 9,000 .OO22 .044 32,000 1391 2.782 11,000 .OO29 .058 34,000 .1171 2.342 12,000 .0036 .072 36,000 .2181 4.362 14,000 15,000 16,000 17,000 300 2,OCO .OO5O .0060 .0082 .OO2O .0016 .100 .120 .140 .164 .032 .040 36,540 Broke. Tenacity per square inch, original section, 36,540 pounds (24.68 kgs. per sq. cm.). Tenacity per square inch, fractured section, 41,028 pounds (28.84 kgs. per sq. cm.). Diameter of fractured section, 0.753" (1.9 cm.). 4,000 .0025 .050 BAR NO. 12 B-D. COMPOSITION. Original mixture : Cu, 58.22 ; Sn, 2.30; Zn, 39.48. T00 30,000 .0240 .48 1,OX> .0012 .... .024 32,000 0254 .=08 2,000 .OO22 .044 34,000 .0268 ..... .536 2,2OO .0024 ... - .048 36,000 .0282 564 2,400 .0026 .... .052 3<3,ooo .0297 594 2,600 .0028 .056 40,000 .626 2,800 .0030 .060 300 .0:50 .030 3,000 .0032 .064 10,000 .C2I5 43 3,200 .0034 .... .068 20,000 .0279 .558 3.4 .0036 .072 30,000 .0345 .690 3,600 .0038 .076 40,000 .0299 .798 3,800 .0041 .082 42,000 .0423 846 4,000 .0044 .088 44,000 .0447 .894 5,000 0054 .108 46,000 0473 .946 6,000 .0064 .128 4 8,coo .0494 i'^ 7,000 .0074 .148 50.000 .0527 8,000 .Oo8l .162 52,000 .0568 .136 9,000 .0098 .... .176 .0615 23 10,000 .0085 .190 56,000 .0674 348 300 .0022 .044 58,000 .0771 542 10,000 .0113 .... .226 60,000 .0873 .746 12,000 .0125 25 62,000 .0958 .916 14,000 0137 .274 64,000 .1277 554 l6,OOO .OI5O .30 66,000 1577 3.154 l8,000 .0165 33 67,000 Broke. 20,000 22,OOO 24,000 .0176 .0189 .0202 352 -378 .404 Tenacity per square inch, original section, 67,600 pounds (47.52 kgs. per sq. cm.). Tenacity per square inch, fractured section, 26,000 28,000 0213 .O226 .426 452 73,160 pounds (51 43 kgs. per sq. cm.). Diameter fractured section, 0.767" (1.9 cm.). 456 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXIL Continued. BAR NO. 40 B. COMPOSITION. Original mixture : Cu, 50; Sn, 5 ; Zn, 45. u Z fe w 2 fc O K - O > 3 z Z ST.. z Z ii I SET. |8jj 2 P SET. H 8 jij Q Z Z * Z Q z 2 K Z c3 3 3*2 3 3 j a, J W Pounds. Inch. Inch. Pounds. Inch. Inch. 300 .... 14,000 .0126 .252 1,000 .0009 .018 16,000 .0141 .282 2,000 .0018 .036 18,000 .0155 .310 2,500 .0022 .044 20,000 .0169 .338 3,000 .0025 .050 300 .0005 3:500 .0028 .056 1,000 .0013 4,000 .0022 .064 22,000 .0184 .368 300 .0000 24,000 .0195 '39 1,000 .0009 26,OOO .0205 .410 4,000 .0032 !o6 4 28,000 .0215 430 6,000 8,000 10,000 300 1,000 10,000 12,000 .0051 .0069 .0087 .0092 .0107 .0002 .0011 .102 .138 .174 .214 3O,OOO .O225 .450 31,300 Broke. Tenacity per square inch, original section, 31,300 pounds (22.00 kgs. per sq. cm.). Tenacity per square inch, fractured section, 31,300 pounds (22.00 kgs. per sq. cm.). Diameter of fractured secUon, 0.798" 12 cm.). BAR NO. 52 B. COMPOSITION. Original mixture : Cu, 60 ; Sn. 5 ; Zn, 35. 300 300 .0007 1,000 .0006 .012 20,000 0092 !i8 4 2,000 .0018 .036 22,000 0098 .196 2,500 .0023 .046 24,000 0105 .210 3,OOO .0026 .052 26,000 0114 .228 3,500 .0030 .060 28,000 0125 .250 4,000 .0033 .066 30,000 0138 .276 300 .00005 300 .0026 .... 1,000 .0006 .... 30,000 0144 4,000 .0027 .... 32,000 0153 : 3 o6 6,000 .0035 .070 34,000 0165 .330 8,000 .0046 .092 36,000 0182 .364 10,000 .0054 .108 38,000 0199 .398 300 .0001 38,330 1 Broke. 10,000 12,000 14,000 16,000 18,000 .0019 .0058 .0068 .0076 .0083 .'ii6 .136 .152 .166 Tenacity per square inch, original section, 38,300 pounds (26.95 kgs. per sq. cm.). Tenacity per square inch, fractured section, 38,534 pounds (24.84 kgs. per sq. cm.). Diameter of fractured section, 0.797" (2 cm.) 20,000 .0090 .180 STRENGTH OF COPPER-ZINC-TIN ALLOYS. TABLE LXXXII. Continued. BAR NO. 59 A. COMPOSITION.- Original mixture : Cu, 70 ; Sn, 5 ; Zn, 25. 457 1 2 w < ss g 2 - 2 H 0- 2 1$ H SET. pi* K u O B SET. . a 1 11 Q 1 isi a H s 3 s u fl Pounds. Inch. Inch. Pounds. Inch. Inch. 300 300 .0004 1,000 .0004 .... .008 20,000 0133 . . . . 2,000 .0009 .018 22,000 .0171 . r. . . .342 2,500 .0012 .024 24,000 .0233 ..... .466 3,000 .OOI4 .... .028 26,000 .0296 .596 3,500 .00l6 .032 28,000 .0376 .752 4,000 .00l8 .... .036 30,000 .0472 .944 300 0000 300 .0078 1,000 0004 .... 30,000 .0470 . . . . * ..... 4,000 .00l8 .... 32,000 .0517 1.034 6 ooo .0023 .046 34,000 .0684 1.368 8,000 .OO29 .... .058 36,000 .0838 1.676 10,000 10,000 12,000 14,000 16,000 18,000 .0036 .0038 .0046 .0059 .0079 .0098 OOO2 .072 .092 .118 .158 .196 38,000 .1028? 2.056 Broke just after reading was taken. Tenacity per square inch, original section, 38,001 pounds (26.61 kgs. per sq. cm ). Tenacity per square inch, fractured section, 39,014 pounds (27.43 kgs. per sq. cm.). Dfameter of fractured section, 0.788" (2 cm.). 20,000 .0129 .258 BAR NO. 67 A. COMPOSITION. Original mixture : Cu, 80 ; Sn, 5 ; Zn, 15. 300 20,000 .0632 1.264 1,000 .0012 .... .024 3 00 ..... .0518 ...... 2,000 .0027 054 2O,OOO .0638 2,500 .0036 .072 22,OCO .0847 1.694 3,000 .0044 .... .088 24,COO .1150 2.300 3i5 .0050 . TOO 26,OOO .1582 3.164 4,000 .0056 .112 28,000 .2650 4. ioc 300 0003 30,000 .2642 5.284 4,000 .0059 3 CO .2502 5.004 5,000 .0069 .... .138 30,000 .2682 5.364 6,000 .008I .... .162 32,000 .3422 6.844 8,000 .0111 .222 34,000 .4127 8.254 10,000 .0150 .... .300 36,000 .5022 10.044 300 0038 37,500 .5804 II. 608 1,000 0052 . . . Broke. 10,000 12,000 14,000 l6,OOO 18,000 OI 57 .0198 .0271 .0346 .0469 542 .692 .938 Tenacity per square inch, original section, 37,560 pounds (26.40 kgs. per sq. cm.). Tenacity per square inch, fractured section, 48,905 pounds (34.38 kgs. per sq. cm.). Diameter of fractured section, o. 700" (i .78 cm.). MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXII. Continued. BAR NO. 73 A. COMPOSITION. Original mixture : Cu, 55 ; Sn, 0.5 ; Zn, 44.5. w Q o H * w Q Q rj K <; K Z c/) ^ "Z <; D a CJ W D a (J H ""a; z u c z S g -a o 5 2w[j O H 2 p s ~> H S5 I 2 S3 J h o jj H sis w Q g Q 3 P s M Q O Pounds. Inch. Pounds. Inch. 300 36,000 .O473 Q4.6 1,000 .00025 .005 38,000 .0586 I . 172 ! 2,000 .00065 .013 15,383,076 40,000 .0748 1 . 496 2,673,796 3,OOO .001 1 .022 13,636,363 300 Set .05535 Set 1.107 4,OOO .00155 .031 12,903,258 40,000 .07815 j 563 | 5,000 .00195 .039 12,820,512 42,000 .09025 1.805 | 6,000 ! .0024. .048 12,500,000 44,000 . IIQ7 2 304 7,000 .00295 059 11,868,474 46,000 *393 2.786 8,000 9,000 .0035 .0038 .070 .076 11,428,571 11,842,105 48,000 50,000 .16255 .2006 3-251 4.014 1,245,762 10,000 .0042 .084 11,904,761 52,000 .2259 4-518 I ......... 3OO Set .00005 Set .001 3OO Set . 19825 Set 3.965 10,000 .0042 .084 52,000 22955 4-59 1 12,000 .0052 .104 11,538,461 54,000 .26605 5-3 21 14,000 .0062* .120 11,200,000 56,000 .29875 5-975 16,000 .0072 .144 n, in, in 58,000 .3263 6.526 18,000 .0082 .164 10,975,668 60,003 .3720 7 440 20,000 300 .0089^ Set .00055 Set !on 11,172,184 300 60,000 Set .3496 Set 6.992 20,000 .0095 .190 62,000 '4636 9272 22,000 .0109 .218 10,009,082 64,000 .4714 */* 9.428 24,000 26,000 28,000 300 28,000 30,000 .01265 .01485 .0178 Set .00515 .01815 .02235 253 .297 c -356 Set .103 .363 447 9,494,07! 8,755,555 7,865,168 68,900 Broke. Tenacity per square inch, original section, 68,900 pounds (48.44 kgs. per sq. cm.). Tenacity per square inch, fractured section, 92,136 pounds (64.77 kgs. per sq. cm.). Diameter of fractured section, .6900" (1.75 32,000 .02755 cm.). 34,000 .03625 .725 STRENGTH OF COPPER ALLOYS. 459 TABLE LXXXIIL TESTS BY TRANSVERSE STRESS. ALLOYS OF COPPER, TIN AND ZINC. DIMENSIONS. Length, 1=22" (5588 cm.); breadth, b = i.oo" (2.54 cm.); depth, d= i.oo" (2.54 cm.). BAR NO. I. COMPOSITION. Original mixture : Cu, 70 ; Sn, 8.75 ; Zn, 21.25. Analysis : Cu, 70.22 ; Sn, 8.90 ; Zn, 20.68. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 3 6 10 20 80 IOO 120 160 2OO 10 3 200 240 280 320 360 400 10 4 400 44 486 520 1^ 600 IO 60! 640 680 g 800 IO 800 840 880 & 1,000 Inch. .0004 .0018 .0067 .0125 .0172 .0215 .0250 .0287 0359 437 0435 .0500 .0568 .0635 .0702 .0764 .0764 .0825 .0891 .0960 .1022 .1086 :ios; ."57 -1234 .1305 .1380 .1468 ^464 '549 .1627 .1716 .1808 .1905 Inch. Pounds. 10 Left 10 nr resista I.OOO Left und Resistan Resistan Resistan 1,000 1,010 1,020 1,040 1, 060 1, 080 1,120 1,160 1,200 1 '3 Resistan Decrease ,200 ,240 ,280 030 ,360 1,400 10 3 10 1,400 1,440 1,480 1,520 1,550 ringing Breaking Modulus metric) Inch. lin. ; showec ice. er strain. :e diminishee :e diminishec :ediminishec .1951 .1967 .1994 2033 .2081 .2145 .2259 2373 2515 :e increased of set, .0004 2536 .2634 .2785 .2962 -3*43 3351 335i .35i6 .3713 .4019 Broke sud< sound. load,/ > =i, of rupture, 1 Inch. .0132 .0098 very slight i ncrease of .0018 .0003 .0050 .OOOQ 7,820,389 8,383-437 9,138,945 9>74 8,i66 10,498,644 i,953,995 11,948,989 11,990,718 I in 5 min. to 1 in 20 min. t in i hr. 55 m 996 Ibs. o 990 Ibs. . to 985 Ibs. 12,575,185 12,914,657 13,202,297 13,434,278 13,716,389 .0291 .0161 n 20 min. to .0257 12,500,184 9 Ibs.' " .0054 .0001 .0056 .0026 13,972,399 14,113,565 14,190.748 14,355,235 14,474,203 .0721 .0681 .0697 10,945,277 ^,491,715 14,436,664 14,454,236 14,428,053 14,277,003 [enly in middle, with 550 Ibs. ? = ^ = 50,541 (3,553 '.'.'.'.'. 14,206,957 14,169,948 14,045,709 13,910,603 13,752,39 460 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXIII. Continued. COMPOSITION. Original mixture : Cu, 88.135 ; Sn, 1.865 ', Zn, 10. Analysis: Cu, 89.50; Sn, 2.07 j Zn, 8.11. LOAD. 2: o u, w g SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 3 10 20 80 100 120 160 200 IO 3 200 240 280 3 20 360 400 10 3 400 440, beam s 480 520 560 600 10 Left unde Resistanc Inch. .0018 .0071 .0119 .0162 .0190 .0224 0255 .0314 0379 .0436 .0511 .0584 .0658 0727 749 nks. .0830 .0921 .1086 .1309 .1631 .1695 r strain, e diminished Inch. Pounds. Resistan Resistan 600 620 640 680 720 760 800 IO 3 800 840 860 880 900 920 940 960 980 1,000 1,020 1,040 I,o6o I, 080 1, 100 1,120 Bar ren Breakin Moduli, (metri Inches. ce diminishe ce diminishe .1749 .1854 5394 .6984 .7154 .9199 . -9859 .1389 .26 36 .56 74 .92 . 12 32 52 .72 .92 3-27 3.67 loved, j load, />-=!, s of ruptur :, 2,250). Inch. i in 4 min. tc i in 41 min. > 578 Ibs. .0 570 Ibs. .0101 .0059 5,325,416 6,354,696 7,001,935 7,960,094 8,439,831 8,896,573 9,633,235 9,976,370 JesJ 2,164,546 .02:14 .0162 .0849 .0820 10,359,026 10,359,028 10,343,283 10,401,776 '.'.'.'.'.'.'.'.'. 10,022,046 9,852,884 6,954,660 t2o pounds *, ./? ^^ - .- in i min. to 584 Ibs. BAR NO. 7. COMPOSITION. Original mixture : Cu, 66.885 ; Sn, 1.865 ; Zn, 31.25. 3 10 20 40 80 120 160 200 IO 3 200 2 4 280 3 20 3 60 400 10 3 400 .0060 .0041 .0091 .0066 9,699,400 9,359,172 10,616,259 ",390,754 11,628,705 ">934,387 12,478,758 ",385,635 12,589,165 12,837,309 12,839,159 440 480 520 560 600 ^ .0920 .1012 .1109 .1239 .1402 M33 Beam sinks. .0257 0233 12,651,391 11,415,131 Left under strain. Resistance diminished in 3 min. to 596 Ibs. Resistance diminished in 10 min. to 594 Ibs. Resistance diminished in 16 h. 15111. to 581 Ibs. i I .0290 I _ , 3 I ..,.. .0274 | Left under strain. Resistance increased in 10 min. to 5 Ibs. .0273 [400 1440 STRENGTH OF COPPER ALLOYS. TABLE LXXXIII. (Bar No. 7). Continued. 461 LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 620 640 680 % % 800 10 3 8d 840 880 920 960 1,000 10 3 1,000 Inch. .1496 .1575 .1836 .2128 .2642 .3069 .3099 .3471 .4296 -5156 .6145 7"7 .7169 Inch. Pounds. 1,040 j 1,080 1,120 1,160 1,200 1,240 1,280 1,320 1,360 1,400 1,440 1,480 1,500 3 Bar remc Breaking Modulus (metric, Inches. 779Q .9498 1-0549 1.19 J -37 '57 J -73 1.93 2.13 2.33 2.61 3-" 3-76 Inches. ^387 1343 1334 6,952,976 3-32 00. ?-!^ = zbdi 49.599 >ved. load, P= i ,5 of rupture, A 34i7>- :i 3,747,836 BAR NO. 12. COMPOSITION. Original mixture: Cu, 58.22 ; Sn, 2-30; Zn, 39.48. 3 10 20 120 160 200 JO 3 200 24O 280 320 3 60 400 10 3 400 520 10 *i & 720 760 800 .0024 .0046 .0093 .0202 .0296 .0418 .0517 0532 .o6l2 .0712 .0802 .0908 .1000 .1010 .1095 "97 .1294 .1403 .1511 'SiS .1629 .1740 .1846 .1944 .2038 10 *2 8 4 880 920 9 60 1,000 10 3 1,000 1,040 1,080 1,120 1,160 1,200 10 3 1.200 Left und Resistanc 1,240 1,280 1,320 ',360 1,400 10 3 1,400 1,440 1,480 1,520 '.2028 .2142 .2247 2344 2433 2550 ^2544 .2642 .2764 .2847 .2951 .3062 306^ sr strain. :e dimmishec .3170 .3276 3398 1" & 3959 .4102 0043 .0032 .0032 .0011 11,760,504 11,040,471 ",7'2,535 10,965,874 10,353,743 10,463,891 :oo6 4 .0046 10,607,511 IQ .593,349 10,616,562 10,672,909 10,607,511 !ooo8 10,607,511 10,637,306 10,792,679 10,724,336 10,819,661 .0114 0093 10,647,661 10,569,132 10,641,044 10,632,674 10,600,509 .0032 .0015 10,869,067 10.846,777 10.869,829 ",578,364 14,321,101 1 in 55 min. to 1,194 lbe 10,627,046 10,570,934 10,550,048 io,574,77i 10,617,922 .0210 .0193 10,310,049 462 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXIII. (Bar No. 12). Continued. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 1,560 i, 600 10 3 i, 600 1,640 i, 680 1,720 1,760 1, 800 10 i, 800 1,840 i, 880 1,920 1,960 2,000 IO Left unde Resistanc 3 2,000 2,040 2,080 2,120 2,160 2,2OO 2,240 2,28o Left unde Resistanc Resistanc Resistanc Resistanc 2,280 2,290 2,300 2,310 2,320 Left unde Resistanc Resistanc Resistanc 2,270 2,280 2,290 2,300 2,310 2,320 2,330 2,340 2,350, bean Left unde Resistanc 2,350 2,360 2,370 Inch. .4236 4395 .4405 4537 .4704 .4332 .5042 5205 .5230 .5333 .5586 .5823 .6076 .6343 r strain. * increased ii .6390 .6594 .6856 .7140 . 74 85 7777 .8106 .8621 r strain. z decreased i z decreased i e decreased i z decreased i .8665 .8685 .8/22 .8763 .8843 r strain. z decreased i z decreased i e decreased ii .8867 .8893 .8919 .8148 .8967 .8990 .9019 .9063 I sinks. .9165 r strain, e decreased i .9189 9 2 3Q 9418 Inch. Pounds. 2,380 2,39 2,400 2,410 2,420 2,430 2,440 2,450 2,460 2,470 2,480 2,490 2,500 2.510 2,520 2,530 2,5*0 2,550 2,560 2,57 2,580 2,59 2,600 2,610 2,620 2,630 2,640 2,650 2,660 2,670 2,680 2,690 2,700 2,710 2.720 2,73 2,740 2,750 2,760 2,770 2,780 2,790 2,800 2,810 2,820 2,830 2,840 2,850 2,860 2,870 2,880 2,890 While p sound breakir Breaking Modulus Inches. 9529 .9650 .9764 .9888 .0048 .0189 0333 .0438 0553 0755 .0865 IOT 3 .1265 I34I 1475 .1647 .1818 .1918 2073 .2293 2445 2585 .2851 .3063 .3288 .3406 3556 3747 3973 .4178 4447 .4665 .4898 5057 5303 5437 5^03 .6106 .6279 6 395 .6581 .6899 .7285 7599 7793 .8111 .8553 .8807 .8936 94^3 .9881 Broke grad Jttinff oh st was heard iff. load,/' =2, of rupture, Inch. .0407 .0387 9,847,245 0743 .0727 9,354, J 74 .1340 .1326 i 10 min. to 8 .1320 8,955,262 Ibs. 5,472,552 7,651,812 n i min. to 2,272 Ibs. n 3 min. to 2,268 Ibs. n 25 min. to 2,260 Ibs. n hr. to 2,256 Ibs. ::::: 4,331,697 n 3 min. to 2 n 10 min. to i 66 hr. 13 m. 312 Ibs. 2,308 Ibs. .02, 260 Ibs. ually in the middle, rain a slight crackling a few seconds before 880 pounds. 95,623 (metric, 6,722). n 10 min. to 2,342 Ibs. STRENGTH OF COPPER AL TABLE LXXXIIL Continued. BAR NO. 52. COMPOSITION. Original mixture : Cu, 60 ; Sn, 5 ; Zn, 35. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 3 10 20 4 80 120 1 60 200 10 3 200 240 280 320 3 60 400 10 3 400 440 480 520 10 600^ 640 680 720 760 800 Inch. .0017 .0036 .0073 .0148 .0237 .OJ2 7 .0408 .O4ir .0497 .o 5 d 3 .0656 .0713 .0770 .0777 .0839 0915 .0993 .1068 H37 .1148 .1216 .1285 1353 .1420 .1487 Inch. Pounds. 10 3 800 840 Beam sinl 880 920 960 I ,OGO Inch. 1495 *55S :ing a little. .1626 .1698 !774 1857 Inch. .0058 .0036 .0022 .OOO6 14,805,645 14,602,823 14,389,192 13,477,5^5 13,039,862 13,063,832 .0063 .0039 I 4,395,26i 14,423,245 14,439,425 14,421,764 14,351,218 3 1,000 1,040 1, 080 1,120 160 200 !i8 5 8 1935 .2032 .2126 .2221 .2324 .OO26 .OOO8 I2,g6o,320 12,704,4-6 -2,704,190 '5,455,93! i3,844, 2 7o 14,324,630 .0098 .0072 13,7^0,839 3 200 240 280 320 360 1,400 .2330 .2426 2547 .2639 .2722 .2804 .0047 .0026 I 3,975,955 13,980,442 13,955,804 13,973,864 14,063,440 .0157 i inch from t 402 po unds. R 3/>/ 13,275,464 3 i,4 02> Breaking Modulus (metric Broke about load, P = i of rupture , 3,239)- tie middle. '.'. '.'. 14,626,432 14,102,841 14,181,934 14,263,500 I 4,33 6 ,79 1 2 Id* ~ 4 "' U/U BAR NO. 55. COMPOSITION. Original mixture : Cu, 65 ; Sn, 5 ; Zn, 30. 44O 0856 14,191,208 oo T 8 480 CQ7I 14,234,223 20 .0037 .oo8r .0168 14,923,498 13,633.811 13,146,888 520 560 600 oP 8 1058 1129 0038 I 4,53,772 14,613,175 14,672,351 TOO .0026 1-3 084. s8i 600 1I2Q 640 14 786 125 3 0001 680 1265 1742 14,840,914 240 280 .0506 .0581 0640 13,094,924 13.305,285 760 800 1420 1495 0064 J 4,776,364 14,776,762 *6o 0781 14,172,058 80^ 1498 0028 840 1-86 880 1680 400 .0781 020 1706 14,142,413 464 MATERIALS OF ENGINEERING NON-FERROUS METALS, TABLE LXXXIII. (Bar No. ^.Continued, u. . 55 Ex. * o ^ O ^ N LOAD. 1 SET. 3p LOAD. i SET. 32 u i u. H < O J Q s Q 2 w Pounds.. Inch. Inch. Pounds. Inch. Inch. 960 . 1906 13,905,628 1,320 .3716 i ,000 .2047 13,487,282 1,360 439 IO .0196 1,400 4433 8,719,012 3 .0177 10 .142! 1,040 .2185 1,400 .4503 i, 080 .2382 1,440 .4704 I,I2O .2579 1,480 .5165 1,160 .2789 1,520 .5608 I,2OO 10 3 OI 4 0597 1,525 Breakin Broke in the middle. ? load, P 1,525 pounds 3 1,200 1,240 3036 .3272 .0576 10,912,409 Modulus of rupture 3/y 1,280 .358o BAR NO. 64. COMPOSITION. -Original mixture : Cu, 75 ; Sn, 10 ; Zn, 15. 3 10 20 120 160 2OO 10 3 200 240 280 320 360 400 10 3 400 44 480 520 560 600 IO 3 600 640 680 7|o 760 800 10 soi- ls 920 .0019 .0036 .006 3 .0143 .0223 0313 .0389 .0390 .0468 0549 .0027 .0702 .0776 .0775 .0843 .0907 .0971 I0 35 .1107 .1115 .1:79 .1251 .1323 ^QS .1472 :i 4 8 2 T 557 .1647 .1738 960 1,000 10 3 1,000 1,040 ,080 ,120 ,160 ,200 10 3 ,200 ,240 ,280 ,320 ,360 ,400 10 3 ,400 ,440 ,480 ,520 ,560 ,600 IO 3 .600 ,640 ,680 ,720 750 Breaking Modulus o t .1847 .1979 .2001 .2113 .2258 2 4|8 .2661 .2858 .2927 3077 .3286 .3536 .3816 .4111 ! 4 is6 4413 4795 .5234 0598 5947 .6090 6399 6 755 7339 Broke near t oad, /*= 1,7 f rupture, '-;=* .0224 .0195 .0637 .0607 1473 M43 14,148,277 13,754,775 11,429,344 .0024 .0032 I5,I22,6l3 l6,OI2,I77 15,228,364 14,264,121 13,9*4,7?7 13,995,219 .OO26 .OOO3 .0049 .0021 ^.gs^aa 1 I 3< 8 ^3,543 13,892,545 1 3,959,33' 14,031,290 14,207,721 14,405,661 M,577,5" 14,728,108 14,752,853 9,270,002 ' .2840 .2798 .Oo8l .0057 14,776,293 14,796,224 14,813,990 14,829,914 14,793,825 tie middle. 50 pounds. J,345 (metric, 4,102). 14,685,542 14,544,151 ! 14.409,115 j STRENGTH OF COPPER ALLOYS. TABLE LXXXIIL Continued. BAR NO. 68. COMPOSITION. Original mixture : Cu, 80 ; Sn, 10 ; Zn, 10. 465 LOAD. DEFLECTION. SET. MODULI'S OP ELASTICITY. LOAD. DEFLECTION. SET. 9,372,595 Pounds. 3 IO 20 g 120 1 60 200 10 3 200 240 280 320 400 520 10 60? 640 680 720 760 800 10 s 960 1,000 10 3 1,000 1,044 1, 080 1,120 1, 160 Inch. .0019 .0038 .0.72 .0132 .0210 .0291 0374 0374 .0456 0536 .0617 .0853 .0921 .0991 .1063 .1120 "37 .1208 .1286 1365 .1528 .1625 .1725 .1839 9SS .2126 ! 2 i66 .2323 2527 Inch. 0025 0006 i Pounds. 1,200 10 3 1,200 1,240 1,280 1,320 1,360 MOO 10 3 1,400 1,440 1,480 1,520 1,560 i, 600 10 , 3 I,COO 1,640 1, 680 1,720 1,760 1,800 10 i,8co 1,840 i, 880 1,920 1,960 2,000 2,040 2,c6o Rollers fle iron sup with a t< Coefficient Breaking 1 Modulus o R Inches. 3325 3419 .3627 .4037 .4400 4934 5647 5720 .6010 .6449 7M3 .7921 -8645 ".8808 .9409 .0216 i '57 .2321 3417 ^ .5879 -7029 .8499 .0079 .2849 4479 w apart. Cc aorts. Theb. )tal deflectio of elasticity oad, P = 2,o< f rupture, = , = 67 Inch. .1171 53 14,427,725 15,739,237 '4,839,942 14,278,983 13,887,648 .2951 2934 6,438,437 0067 0053 13,668,369 13,566,365 13,468,990 13,379,554 13,266,871 '3,395,96' '3.534,458 13,626,9^7 13,681,226 13,911,448 '5468 5432 4806,460 0150 0130 '3,759,793 13,732,139 13,608,407 I3 ,668, 3 68 13,614,630 ^9589 9546 3,484,072 2,586,772 mtinued tests on cast- ir broke at 2,320 pounds [i of 2.797". , 2,154,009. to pounds. 117 (metric, 4,718). .0417 .0405 12,215,380 30 466 MATERIALS OF ENGINEERING NON-FERROUS ME TALS. TABLE LXXXIII. Continued. BAR NO. 71. COMPOSITION. Original mixture : Cu, 85 ; Sn, 10 ; Zn, 5. LOAD. g g SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 3 10 20 40 90 1 20 160 200 10 3 200 240 280 3 20 3 60 400 10 3 400 440 480 520 560 600 10 600 640 680 720 760 800 10 Sol 840 880 920 960 Left unde Resistanc< Resistance Resistance Resistance Resistance Resistanc r Resistance Resistance Resistanc Resistanc Resistanc Resistance 920 940 945 950 955 Inch. .0013 .0031 .0064 .0131 .0201 .0275 3S5 .0364 .0420 .0508 .0589 .0670 .0752 759 .0842 .0919 .0998 1073 35 .1141 .1138 .1270 !347 .1425 .1501 .1506 .1598 .1691 .1787 .1894 r strain. : decreased i ; decreased i : decreased i : decreased i : decreased i : decreased i : decreased i ; decreased i : decreased i ; decreased i i decreased i ; decreased i .1896 .1914 .1920 1943 .1951 Inch. Pounds. 960 965 970 975 985 990 1,000 10 3 1,000 1,040 1, 080 I,I2O 1,160 Left unde Resistance Resistance Resistance Resistanc Resistance Resistance Resistance Resistanc Resistance Resistance i, 066 I, TOO I, IIO 1,120 1,130 1,135 1,140 I,t45 1,150 M55 1,160 x,'6 5 1,170 i,i75 1,180 1,200 10 3 1,200 1,240 1,280 ''320 1,360 1,400 10 3 1,400 1,440 1,480 1,520 1,560 Inch, .1958 .1969 .1983 .1994 .2005 .2017 !2o66 .2078 .2166 .2306 2537 .2832 r strain. ; decreased i j decreased i ; decreased i i decreased i : decreased i ; decreased i ; decreased i ; decreased i ; decreased i ; decreased ir 2833 .2897 .2914 .2937 .2958 .2970 .2986 .3005 .3023 345 .3076 .3110 .3Hi 3^75 .3221 .3304 .3305 .35X1 .3691 .4204 .4704 .5296 .5500 .6052 6534 735<5 .8214 Inch. .0024 .0015 .0042 .0026 1 5,737,2i7 15.245,428 14,896,295 14,562,759 14,192,102 1 3i742,357 397 .0382 11,806,720 13,742,357 I3,444,7 86 13,252,393 13,106,5 :6 12,974,833 n 2 min. to 1,118 Ibs. i 3 min. to 1,112 Ibs. i 4 min. to 1,110 Ibs. i 7 min. to 1,104 Ibs. i 12 min. to 1,100 Ibs. i 27 mm. to 1,093 lbs - n 42 min. to 1,090 lbs. i i hr. i2m. to i, 087 lbs. i 2 hr. i2m. to 1,082 lbs. 16 hr. i2m. to 1,066 lbs. !68 .0051 12,746,771 1 12,740,466 12,703,614 10,730,571 12,906,151 0134 .0116 13,031,152 13,060,650 13,038,405 13,009,131 13,000,763 '.'.'.'.. i i min. to 94 i 2 min. to 9< i 3 min. to 9; i 4 min. to 9^ i 9 min. to 91 i 14 min. to $ i 29 min. to c ti 44 min. to g ti i hr. i4mir n i hr. 44 mil n 2 hr. 44 mil n 2 hr. 74 mil 4lbs. olbs. 8lbs. 7 lbs. albs. 30 % Ibs. 26 Ibs. 25 Ibs. i. to 9^3 Ibs. i. to 922 Ibs. i. to 9 20 Ibs. i. to 920 Ibs. !ii66 .1141 8,859,329 .2794 .2764 6,448,116 STRENGTH OF COPPER ALLOYS. TABLE LXXXIII. (Bar No. 71). Continued. 467 LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. Inch. it Pounds. 1, 600 10 1, 600 1,640 1, 680 ''720 1,760 1,800 1,840 1,880 Inches. .0206 '.9486 1.0198 1.1191 1.2726 1-379 1 1.5061 1.6896 1.8556 Inch. Pounds. 1,920 1,960 2,000 The bea crease Breaking Modulus < Inches. 2.0401 2.3676 2.5621 m could not of load, load, P = 2, of rupture, .6169 .6132 be raised with an in- ooo pounds. 62,470 (4,392 metric). BAR NO. 72. COMPOSITION. Original mixture : Cu, 90; Sn, 5 ; Zn, 5. 3 10 20 C 120 160 200 10 3 200 X IS 400 10 3 400 % 520 10 600 640 Left unde Resistanc Resistanc Resistanc Resistanc Resistanc Resistanc Resistanc Resistanc Resistanc Resistanc Resistanc 591 20 625 .0018 .0036 .0145 .0221 .0297 0374 : 03 76 .0461 535 .0608 .0681 0754 0757 .0827 .0007 .0992 .1092 . I2O2 .1246 .1342 r strain. 2 decreased i 2 decreased i 2 decreased i 2 decreased i 2 decreased i 2 decreased i 2 decreased i 2 decreased i 2 decreased i 2 decreased i 2 decreased i 1342 1387 .1392 630 635 640 < 45 650 IS 680 7f 760 800 10 ao! 840 Left und Resistan Resistan* Resistan* 'Resistan Resistanc Resistan< Resistan Resistanc Resistan* Resistan* Resistan* Resistanc Resistam Resistanc Resistanc Resistanc Resistanc Resistanc Resistanc 752 780 800 820 825 830 I 35 840 '397 .1406 -14'S .1426 .1441 .1456 1473 1525 I 7i .1969 .2287 .2451 .2814 er strain. :e decreased :e decreased :e decreased :e decreased :e decreased :e decreased :e decreased :e decreased :e decreased :e decreased :e decreased :e decreased i e decreased e decreased e decreased e decreased e decreased i e decreased e decreased .2814 .2865 .2900 2951 33 3050 3094 -0035 .0019 14,309,323 14,862,866 14,145,348 13,921,359 13,811,961 13,710,398 0997 .0979 8,968,410 .0071 .0049 13,347,532 13,418,250 i3,493,9!9 13,553,364 13,601,300 in i m. to 800 Ibs. in 2 m. to 795 Ibs. in 3 m. to 792 Ibs. in 4 m. to 790 Ibs. in 5 m. to 789 Ibs. in 6 m. to 788 Ibs. in 13 m. to 782 Ibs. in 21 m. to 779 Ibs in 31 m. to 777 Ibs. in 46 m. to 774 Ibs. in i hr. i m. to 772 Ibs. n ihr. i6m.t077iilbs. in i hr. 46 m. to 770 Ibs. in 3 hr. i m. to 766 Ibs. in 4 hr. i m. to 764 Ibs. in 5 hr. 31 m. to 763 Ibs. n 21 hr. 15 m. to 752*105. in 23 hr. 45 m. to 752 Ibs. n 24 hr. 36 m. to 752 IDS. .0246 0233 13,640,770 13,568.306 13,439,504 13,180,961 12,797,923 n i m. to 628 Ibs. n 2 m. to 626 Ibs. n 3 m. to 624 Ibs. n 4 m. to 623 Ibs. n 5 m. to 622 Ibs. n 6 m. to 621 Ibs. n ii m. to 618 Ibs. n i6m. to 617 Ibs. n 19 hrs. 51 m. to 596 Ibs. n 40 hrs. 36m. to 591 Ibs. n 42 hrs. 1 1 m. 10591 Ibs. 468 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXIII. (Bar No. 72). Continued. o t s g LOAD. w SET. j D ^ H LOAD. 1 SET. >-> H 3 It, D< -1 Q < w O >-> X Q Pounds. Inches. Inch. Pounds. Inches. Inch. 845 .3175 I,I2O 1.3085 850 .3237 860 i 802 s 6 880 .3510 1,240 , 9, 9 920 960 .4320 .5587 1,280 The bean_ 2.6325 i could not be raised w ith an in 1,000 .7191 3,565,351 crease of weight. 10 3 .5485 5455 Breaking load, P 1,280 pounds. Modulus of rupture, 1,000 .7567 1,040 .8634 R - - = 41,334 (2,906 metric). 1, 080 I.IOOI BAR NO. 73. COMPOSITION. Original mixture: Cu, 55 ; Sn, 5 ; Zn, 44.5. 3 10 20 120 160 200 IO 3 200 240 280 3 20 360 400 10 3 400 $ IF 600 10 60! 640 680 720 760 800 10 800 840 880 920 960 1,000 10 . 3 1,000 1,040 1, 080 1,120 1,100 I,2OO .0021 .0051 .0122 .0217 .0321 .0417 .0519 .0520 .0631 734 .0813 .0899 .1001 .0997 .IIO2 .1199 .1300 .1402 .1516 .1518 J 623 :3 .2024 .2164 .2167 .2296 2443 .2585 2758 .2923 !2 94 8 .3146 .3338 3571 3*5* .4271 10 3 ,200 ,240 ,280 ,320 ,360 1,400 IO Left und Resistam Resistam IO 3 1,400 ,440 ,480 ,520 ,560 ,600 ,640 ,680 ,720 ,760 ,8co 10 3 ,800 ,840 ,880 ,920 ,960 ooo 10 3 2,000 2,000 2,040 2,080 2,100 Breaking Modulus j .4284 4575 4973 539 .5876 .6419 er strain. :e increased :e increased .2970" 2933 .6508 .7197 7853 8571 9485 .0361 1295 .2316 3347 4535 5744 ! 5 866 7459 .8619 .0244 .2087 .3178 .3513 7738 3.0498 3.0498 Beam coul this pres load, P = 2, of rupture, ? _ 3/v _ ~27^~ ' .1286 .1265 .0024 .0024 .002 3 .0008 11,125,506 9,301,654 10,459,002 10,605,623 10,885,388 io,932,579 [2986 .2965 n 20 m. to >-j n 15 hrs. 45 "ir 6,187,577 10,790,506 10,822,358 11,166,563 11,360,639 11,336,420 Ibs. . to 10 Ibs. ::::.' 4,381,050 .0046 .0018 .0140 .0119 .0440 .0417 11,327,423 11,357,480 11,348,016 11,331,828 11,22^,276 11,187,203 r i,o;5,376 10,859,347 10,652,784 10,015,963 10,379,284 ro,2i 9 ,2 54 10,996,882 9,874,995 9i705,798 1.1384 1.1358 1.9144 1.9096 3,243,526 2,448,014 d not be raised aftef sure was attained, loo pounds. 2,308 (metric, 5,083). 9,378,526 9,179,045 8,897,912 7,970,978 STRENGTH OF COPPER ALLOYS. TABLE LXXXIII. 469 BAR NO. 74. COMPOSITION. Original mixture : Cu, 67.5 ; Sn, 5 ; Zn, 27.5. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. i b Q SET. MODULUS OF ELASTICITY. Pounds. 3 JO 20 4 80 120 1 60 200 10 3 203 2 4 280 320 3 60 * 400 10 3 400 440 480 520 & 600 10 < 640 680 720 760 800 10 Sol 840 880 Inch. .0016 .0033 .0070 .0140 .0218 .0294 0393 .0396 .0482 .0562 .0642 .0727 .0809 !o8o7 .0886 .0963 1037 .1107 .1180 "77 1255 iS'S '379 .1442 .1508 .I5H ::& Inch. Pounds. 920 960 1,000 10 3 1,000 1,040 1, 080 1,120 1,160 1,200 10 3 1,200 1,240 1,280 1,320 1,360 1,400 10 3 1,400 1,440 1,480 1,520 1,560 1, 600 10 1,600 1,640 1. 660 Breaking Modulus 1 Inch. .1721 .1801 .1888 !is 9 8 .1980 .2083 .2211 2 3|3 .2469 .2498 .2632 .2791 .3013 3I ^ .3360 ^3396 3521 .3727 .4013 4301 .4620 .4621 .4874 Broke, load, /=!, of rupture, '-35- Inch. .0083 .0068 14,871,767 H,794,934 14,701,230 .0025 .0009 16,821,775 17,390,724 15,208,723 15,278,489 15,105,267 14,125,146 14,578,869 14,390,973 .0190 0175 13,490,121 .oo?8 .0013 13,820,378 13,828,573 13,834,729 13,712,725 13,723,572 1 2,i59.9 I 3 .0039 .0024 13,783,981 13,834,726 13,918,109 14,040,945 M,"3,l8 5 .0521 .0503 10,513,107 .0044 .0032 14,154,417 14,352,805 ES 14,724,630 .1167 .1151 9,610,361 660 pounds. ,976 (metric, 3,935). -j '....'. 14,784,385 j 14,857,187 BAR NO. 76. COMPOSITION. Original mixture : Cu, 80 ; Sn, 12.5 ; Zn, 7.5. 3 10 20 120 1 60 200 IO 3 200 240 280 320 .OO2I .0053 .0109 .0193 .0271 .0361 .0463 !o 4 68 .0^46 .0614 .0682 ^ 400 10 3 400 440 480 520 600 10 Left und Resistanc .0750 .0826 .'0824 .0897 .0964 .1031 .nor .1166 :r strain, e increased i 0046 OO22 12,714,988 12,827,876 0040 0016 9,996,061 9,720,941 10,980,131 11,729,695 11,740,527 "i442,576 0057 0035 n i hour to 6 I2 ,993,767 13,189,824 i306o,397 i3473,348 13,630,993 .... 11,643,764 12,079,930 12,429,120 pounds. 4/0 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXIII. (Bar No. ^.Continued. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 600 640 680 720 760 800 10 3 800 840 880 920 960 1,000 10 3 1,000 ,040 ,080 ,120 ,100 ,200 10 3 ,200 ,2 4 ,280 ,3|0 ,360 , 4 00 10 Inch. .1167 .1232 .1301 .1366 .1440 .1506 .1506 1587 1675 1954 .1976 .2064 .2173 .2299 2434 2594 ! 2 6 4 6 .2766 .2926 .3126 3313 3529 Inch. .0031 .'0081 .0064 Pounds. 3 ,403 ,440 ,480 ,520 ,560 ,600 IO ,^ ,640 ,680 ,720 ,760 ,800 10 3 ,800 ,840 ,880 ,Q20 , 9 60 ,OOO 10 Broke wl had rez Breaking Modulus . Inch. ! 3 026 3791 .40^6 .4364 .4656 .5081 .5^3 5364 .5706 .5986 ^559 .6990 .7148 7579 .7965 .8485 .9090 .9652 lile putting iched 1,950 p load, P=2, of rupture, -fi- Inch. .0964 13,760,813 I 3. 8 45 > 426 13,962,296 13,980,603 14,071,480 1 .2011 .1983 8,209,046 .0182 .0156 14,020,942 13,950,222 13,791,965 i3> 6 7 1 >35 I3i556,58i .3462 3425 6,821,346 13,347,452 ^5518 5473 strain on anc Dunds. ooo pounds. 5,073 (metric 5,508,330 .0447 .0428 12,254,229 1 before it 4,645). .0991 10,508,678 BAR NO. 77. COMPOSITION. Original mixture: Cu, 82.5 ; Sn, 15 ; Zn, 25. 3 10 20 40 80 120 160 3 200 2 4 280 320 3 6o 400 10 3 400 .0012 .0031 .0071 .0154 0235 .0307 .0421 .0422 .0498 0575 .0655 .0732 .0800 .0802 .0874 .0950 .1017 .1090 .OO2I .0006 .0025 .OOI2 17,107,474 14,938,924 13,774-851 I3,54,3 81 13,819,719 12,596,953 12,779,076 12,912,424 12,954,669 13,040,943 13,258,292 13,349,313 13^396,852 13,558,134 13,623,198 6oo 10 3 603 640 680 720 760 800 10 Left under strain. Resistance increased in .0046 "55 .1161 .1217 .1286 .1361 1437 .1506 .0027 .0014 i3,774,45i 10 So? 840 880 9 20 9 60 1,000 10 3 ,1463 . 1562 ,1627 .1691 1775 1857 13,944,630 14,021,209 14,027,877 14,024,081 14,085,034 .0046 27 hrs. 50 m to 14 Ibs. .0043 .0027 .0125 .0105 14,259,881 14,342,099 I 4,4 2 5,5 2 8 14,341,363 14.279,259 STRENGTH OF COPPER ALLOYS. TABLE LXXXIII.(Bar No. 77). Continued. 471 LOAD. Q SET. MODULUS OF ELASTICITY. LOAD. Q SET. MODULUS OF ELASTICITY. Pounds. 1,000 1,040 i, 080 1,120 1,160 1,200 10 3 1,200 1,240 1,280 X ' 3 1,360 1,400 10 3 1,400 1,440 1,480 1,520 1,560 1,600 10 1,600 Inch. .1862 .1940 .2049 .2165 .2310 2447 '2473 .2015 .2791 .2992 3^74 339 3430 3599 .3860 .4150 3? .4929 Inch. Pounds. 1,640 1,680 ''720 1,760 1,800 10 ,,80! 1,840 1,880 1,920 1,960 2,000 10 3 2,000 2,040 2,o8o 2,000 Breaking Modulus . Inches. 5167 ioSo? .6950 7356 .7842 .8311 .8924 .9558 .9762 1.0197 1-0895 Broke load, P=2, of rupture, *=.= Inch. ... . 14,215,075 .0311 .0275 13,003,632 : 3 i8i 3!5 6 7,011,877 5305 5247 5,548,564 .0822 .0800 10,823,095 090 pounds. 9,045 (metric, 4,854)- .1730 .1705 8,607,535 BAR NO. 78 COMPOSITION. Original mixture : Cu, 60 ; Sn, 2.5 ; Zn, 37.5. 3 10 20 120 160 200 10 3 200 240 280 3* 360 400 10 3 400 440 480 520 & 10 60^ 640 .0014 .0079 .0119 .0197 .0284 0357 .0431 .0446 5i3 .0000 .0756 .0839 !o8 4 o .0917 .0996 :S3 1235 .1239 .1319 680 720 760 800 IO 800 840 880 920 960 1,000 10 3 1,000 1,040 1, 080 1,120 1, 100 1,200 10 3 1,200 1,240 1,280 Left und Resistanc Resistan .1307 .1489 .1581 .1676 :i683 1785 .1887 .2010 .2137 .2256 .2244 .2426 2595 .2791 .2998 3244 3245 & ?r strain. :e decreased :e decreased !oo8 3 .0070 13,698,602 13,608,229 i3,5 2 8,37i 1 3, 432 ,2 10 .0019 .0001 .0013 .0002 7,124,701. 9,459,685 11,428,458 11,891,227 I2,6l2,9l8 13,059, '98 13,243,564 13,124,254 I3,l66,II2 13,133,199 13,185,394 13,401,225 I34I7,197 .0215 .0201 12,474,544 .0032 .0012 13,503,526 13,562,685 13,562,685 13,609,517 13,672,506 !o 5 66 0546 10,410,323 13,655,229 in 2 min. to 1,265 I 08 - in 4 min. to 1,260 Ibs. 47 2 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXITI. (Bar No. 78). Continued. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. h. Id Q SET. MODULUS OF ELASTICITY. Pounds. Resislanc Resistanc Resistanc Resistanc ,260 ,270 ,280 ,2go ,300 ,320 ,360 ,400 10 3 ,400 ,440 ,480 ,5 20 ,560 ,600 10 i, 600 Inch. z decreased i 2 decreased i e decreased i : decreased i 3699 37^8 .374i .3762 .3788 .3852 43 11 .4760 4775 501 7 5430 59 6 S .6476 .7044 .7064, Inch. n 7 min. to n 22 min. to n 4 h. 52m. t i 12 h. 32 m. 1,257} Ibs. 1,253* Ibs. 3 1,245} Ibs. to 1,244 Ibs. Pounds. 1,640 1, 680 1,720 1,760 1,800 10 3 i, 800 1,840 i, 880 1,920 1,960 2,000 10 3 2,000 2,030 Breaking Modulus R Inches. 7345 7979 .8654 .9268 1.0156 .0181 .0456 ' L 5 I 3 .2366 .3206 .4426 1-4574 Broke in th load, P = 2 of rupture, 3/Y -2^3 = Inch. * 5333 .5306 4,987 853 !88 2 i .8800 e middle. 030 pounds. 9,508 (metric 3,901,644 .1381 .1360 8,277,226 , 4,886). .2942 .2921 6,392,409 BAR NO. 80. COMPOSITION. Original mixture : Cu, 77.5 ; Sn, 10; Zn, 12.5. 3 10 20 40 80 120 160 200 IO 3 200 240 280 320 3 60 400 IO 3 400 440 480 520 560 600 10 3 600 640 680 Left unde Resistanc .0014 .0083 .0111 .0208 .0290 .0368 .0448 .0449 .0523 58 5 .0661 .0740 .0814 .0810 .0884 955 .1025 .1095 .1165 ;6 5 1235 .1304 r strain, e decreased i 680 720 760 800 10 sol 840 880 920 960 1,000 10 3 ,000 ,040 ,080 ,I2O ,160 ,200 IO 3 ,200 ,240 ,280 , 3 20 ,360 ,400 IO 3 1.400 .1315 .1364 I 445 1515 ''I 24 .1601 .1690 .1809 '959 .2099 .2130 .2251 .2419 .2613 .2824 3023 '3086 3249 -3445 3765 .4039 4475 .4 50 5 .0104 .0085 13,87^289 13,821,159 1 3,876,377 .0019 .0005 6,332, 141 9,469,689 10,107,072 10,873,815 "4 2 5i3 8 7 ",731,423 .0297 .0279 !3,787,536 13,683,421 13,364,351 12,519,481 .0024 .0010 12,058,914 12,577,687 12,721,759 12,784,079 12,913,211 .0045 .0029 n 43 min. to 13,079,741 13,207,981 *3,33M72 I3,439ii73 I 3,533.934 13,617,950 13,703,452 672 pounds. .0770 0752 10,431,381 .1776 1747 8,221,172 STRENGTH OF COPPER ALLOYS. TABLE LXXXIII. (Bar No. 80). Continued. 473 LOAD. j SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 1,440 1,480 1,520 1,560 1,600 10 3 i, 600 1,640 1,680 1,760 1,800 Inch. .4880 5215 5710 .6148 .6675 !6 7 6o .7096 7573 8255 .8785 .9628 Inch. Pounds. 10 ,,*J 1,840 1, 880 1,920 1,960 Breaking Modulus Inches. 9777 1.0177 1.0903 i . 1930 Broke just load, P = i of rupture, Inch. 5756 5718 3435 3410 6,293,140 after beam rose. ,960 pounds. ,849 (metric, 4,489). 4,912,868 BAR NO. 87. COMOSIT~ON. Original mixture : Cu, 77.5 ; Sn, 12.5; Zn, 10. 3 10 20 c 120 1 60 200 10 3 200 2 4 280 3fO 360 400 10 3 400 440 480 520 56o 600 10 '600 640 680 720 760 800 10 hi 840 880 920 960 1 ,000 10 .0018 .0063 .0108 .0185 .0263 0336 Q4 I 5 .0427 .0520 .0603 .0675 0743 .0816 .0817 .0887 .0958 .1025 .1089 53 .1161 .1219 .1284 .1348 .1413 .1485 T 493 1557 .1630 .1707 1794 .1897 3 1,000 1,040 1, 080 1,120 1,160 I,2OO 10 3 1,200 1,240 1,280 1,320 1,360 1,400 10 3 1,400 ,440 ,480 ,520 ,560 ,600 IO 1, 600 1,640 1,680 1,720 1,760 1,800 IO 1,800 1,825 Breaking Modulus j . 1912 .2004 .2113 .2225 2377 .2570 .2592 .2705 .2845 .3029 .3240 3493 3553 .3690 395 4*34 4597 4950 543 5225 .5513 .6008 .6490 .6885 Bro'lce 50 load, P= i, of rupture, '== .0106 .0021 .OOO6 035 .00l8 .0043 .OO2I 8,550,829 9,975,965 11,647,614 12,289,782 12,826,242 12,980,775 ,0380 .0348 12,576,762 12,431,587 I2 1 507. 1 7 2 12,769,235 12,050,657 13,203,483 10,795,632 .0892 13,361,271 13,495,668 13,664,637 '3*850,936 14,016,565 !i86 5 .1830 8,706,298 .0055 .0038 14,141,485 14,264.731 14,386,704 14,486,388 14,510,495 ! 3 288 .3245 7,041,858 825 pounds. 1,705 (metric, 4,538). ::::: 14,531.465 I 4,54 I i 6 54 14,516,869 M.413'435 .0119 474 MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE LXXXIIL Continued BAR NO. 88. COMPOSITION. Original mixture : Cu, 82.5 ; Sn, 12.5 ; Zn, 5. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 3 10 20 40 80 1 20 160 200 10 3 200 240 280 320 360 400 10 3 400 440 480 520 560 600 10 ^ 640 680 720 760 800 10 *2 i 920 960 1,000 10 3 1,000 1,040 1, 080 I,I2O 1,160 1,200 Inch. .0020 .0047 .0090 .0075 .0254 .0338 .0410 .0411 .0509 .0590 .0666 0739 .0810 iosie .0888 .0958 .102 1 .1097 .1171 .1169 .1231 .1310 1373 .1451 .1528 534 .1608 .1783 .1880 .1983 .'^988 .2090 .2206 2341 .2502 .2675 Inch. Pounds. 10 3 ,200 ,240 ,280 '320 ,36o ,400 10 3 ,400 ,440 ,480 ,520 ,56o ,600 10 ,60! ,640 ,680 '720 ,760 ,800 10 Left und Resistant 10 i, 800 1,840 i, 880 1,920 1,960 2,000 10 3 2,000 2,040 2,080 2,120 Broke ju Breaking Modulus Inch. .2726 .2864 .3065 3258 .3487 373 .3825 .4017 .4326 4733 .5062 5520 .5649 5875 .6242 .6828 .7412 .8048 er strain. :e increased isioS .8490 .9086 .9788 .0530 .1326 1576 2173 .2980 .6100 st after beair rload, J P^ 2) of rupture, -&- Inch. .0520 .0494 .0023 .0003 .0038 .0017 .0050 .0039 11,327,661 11,831,112 12,169,145 12,576,378 12,601,287 12,985,365 I2 i55 I ? 67i ."53 .1124 9,991,423 12,790,394 12,967,797 13,145,680 13,190,091 13,377,788 *3,557, 6 9! 13,589,062 ; 13,639,627 | 2431 .2399 7,715,943 ^4380 4328 in i hour to .4306 .4287 5,953,77 s 23 pounds. .0098 .0075 13,839,806 13,818,016 I 3,959t5o8 !3,94 2 939 I3,937ii73 I .0215 .OT 94 13,905,974 ; I 3i836,74 I I 13,735,503 1 3<,593, 1 99 13,424,108 -759 .7014 4,700,689 rose. 120 pounds. 9,960 (metric 4,918). 10,791,095 STRENGTH OF COPPER ALLOYS. TABLE LXXXIIL Continued. BAR NO. 89. COMPOSITION. Original mixture : Cu, 85 ; Sn, 12.5 ; Zn, 2.5. 475 LOAD. Pounds. 3 10 20 120 1 60 200 10 3 200 240 280 $ 400 10 3 400 440 480 520 & 600 10 6oi 640 680 720 760 800 10 Soi 840 880 Q20 060 1,000 10 3 1,000 1,040 DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Inch. .0021 .0067 .0112 .0207 .0292 .0367 .0444 .0450 0536 .0620 .0694 .0765 .0840 !o8 4 ; .0915 .0981 .1^55 .1131 .1208 .1210 .1279 .1352 .1427 .1504 1594 !ieo6 .1692 .i 79 8 1930 .2095 .2265 .2307 .2460 Inch. Pounds. i, 080 1,120 1,160 1,200 10 3 1,200 1,240 1,280 Inches. .2647 .2880 3193 3505 Inch. .0031 .0010 .0053 .0031 7,877,604 9,424,989 10^99,024 10,845,190 H,505,l6 4 11,886,372 1245 .1214 9,035,081 3625 3993 4435 .5130 .5783 .6527 11,816,403 11,918,049 12,168,285 12,419,811 12,566,652 x'jfio 1,400 10 3 1,400 1.440 1,480 ^520 ' i, 600 10 3 1,600 % ,720 '740 ,760 , 7 8o ,800 ,820 ,840 ,860 ,880 1,000 1,920 The bear crease Breaking Modulus J 3707 .3671 5,660,481 6 743 .7230 .8345 9425 .0777 .2199 .2255 3M5 ''Si 9655 0745 .1805 2995 4075 :lg .8285 Q could not of load. load,/'=i, of rupture, '= = :8 47 2 .8 4 2 3 3,461,264 ioos; .0049 12,690,260 12,915,497 13 '2'i 77 13,066,650 13,107,604 .0172 .0143 13,205,304 13,273.061 131315*159 13*335,359 13,244,652 2,257,161 13,101,403 be raised with an in- 920 pounds. 2,405 (metric, 4,387). .0438 .0410 11,651,201 CHAPTER XIII. CONDITIONS AFFECTING STRENGTH OF NON-FERROUS METALS AND ALLOYS. 268. The Conditions Affecting the Strength of the Non- Ferrous Metals are precisely such as have been found to modify the valuable properties of iron and steel, and of other materials of construction used by the engineer. The effect of every change, whether chemical or physical, of internal or of external conditions, affecting the metal is seen in a modifi- cation of its strength, elasticity, ductility and resilience. Change of temperature, either gradual or sudden, alteration of methods of manufacture, differences, however slight, of composition and of density, and every variation of the mag- nitude, and of the number of applications, of the load has an effect, more or less marked and important, upon the value and reliability of the metal as a structural material. The effect of heat and of variation of temperature upon the non-ferrous metals and upon the alloys has been but little studied ; but some important facts have become well ascertained. 269. The Strength of Copper is modified by tempera- ture in the same general way as iron (Part II., Arts. 285-288). It is reduced steadily, and according to a simple law, as tem- perature rises, finally becoming zero at the point of fusion. Decrease of temperature causes increase of strength. A committee of the Franklin Institute, of the State of Pennsylvania, consisting of Professor W. R. Johnson, Benja- min Reeves, and Professor A. D. Bache, were engaged, during a period extending from April, 1832, to January, 1837, in experiments upon the tenacity of iron and of copper, under the varying conditions of ordinary use. CONDITIONS AFFECTING STRENGTH OF ALLOYS, 477 The effect of change of temperature upon those metals was investigated with equal intelligence and thoroughness, and most valuable results were obtained. Upward of one hundred experiments upon copper, at temperatures ranging from the freezing point up to 1,000 Fahrenheit, exhibited plainly the fact that a gradual diminu- tion of strength occurs with increase of temperature, and vice versa, and that the change is as uniform as the unavoidable irregularities in the structure of the metal would allow. The law of this variation of tenacity, within the limits between which the experiments were made, was found to be closely represented by the formula, D* = C T 3 , i. e., the squares of the diminutions of tenacity vary as the cubes of the observed temperatures measured from the freez- ing point. The following are the tenacities of copper at various temperatures, as determined by experiment, to the nearest round numbers : TABLE LXXXIV. TENACITIES OF COPPER WITH VARYING TEMPERATURES. TEMPERATURE. TENACITY. TEMPERATURE. TENACITY. F. C. Lbs. per sq. in. Kilogs. per sq. cm. F. C. Lbs. per sq. in. Kilogs. pei sq. cm. 122 50 33,000 231 602 316 22,000 212 100 32,000 225 801 427 19,000 144 302 150 31,000 218 912 490 15,000 105 482 250 27,000 190 I 016 546 11,000 77 545 290 25,000 176 2,032 i,ni o 270. The Effect of Heat on Bronze and the kalchoid al- loys of copper, tin and zinc was determined by the British Admiralty at Portsmouth in the year 1877.* * London Engineering, Oct. 5, 1877, 478 MATERIALS OF ENGINEERINGNON-FERROUS METALS. The metal was cast in the form of rods one inch in diameter, and composed of five different alloys as follows : No. i. Copper, 87.75 ; tin 9.75; zinc, 2.5. No. 2. Copper, 91 ; tin, 7 zinc, 2. No. 3. Copper, 85 ; tin, 5 zinc, 10. No. 4. Copper, 83 ; tin, 2 zinc, 15. No. 5. Copper, 92.5 ; tin, 5 ; zinc, 2.5. The specimens were heated in an oil bath near the test- ing machine, and the operation of fixing and breaking was rapidly and carefully performed, so as to prevent, as far as possible, loss of heat by radiation. The strength and ductility of the above test-pieces, at atmospheric temperature, were as follows: No. I, 535 pounds, 12.5 percent.; No. 2, 825 pounds, 16 per cent.; No. 3, 525 pounds, 21 per cent.; No. 4, 485 pounds, 26 per cent, and No. 5, 560 pounds, 20 per cent. As the heat increases a gradual loss in strength and ductility occurs, up to a certain temperature, at which, within a few degrees, a great change takes place, the strength falls to about one half the original, and the ductility is wholly gone. Thus in alloy No. I, at 400 F. (204 C.) the tensile strength had fallen to 245 Ibs., and the ductility to 0.75 per cent. ; the precise temperature at which the change took place was ascertained to be about 370 F. (188 C.). At 350 F. (177 C), the tensile strength was 450 Ibs., and ductility 8.25 per cent. At temperatures above the point where this change begins and up to 500 F. (260 C.) there is little if any loss of strength. Phosphor-bronze was less affected by heat, and at 500 F. (260 C.) retained two-thirds its tenacity and one-third its ductility. Muntz metal (copper, 62; zinc, 38) was found reliable up to the limit, and iron and steel were not injured. The following table exhibits the results of these experi- ments in convenient shape. CONDITIONS AFFECTING STRENGTH OF ALLO YS. 479 w i OS ioio<> 10 K VO ^ "5 >o * ^ M ^2 2>O>doo ^ ci ei ;iOOOfOiOMioOOO ^J "loRJoioio^ci e? u ."?...-;; s: ~ t v S^? SM "fl ;c '5 I a? : : ? ^ : a : : *; ; ' ; J> w g> J^ | j 10 fO M M | ^ ^ K k O M O O O 00 $ tit r s I HN o.= UHN UHN HS o 10100 ^S- V 8 JT t Its ft 8 S> 8 ft 8 S. 8 c- -C*^ M < 21 083 I 552 22 2 VJ I 418 20 ^ I 2o6 l8 5 Steel (wire) 7 622 1.728 24. Q 2 I2Q -3Q 4 I.Q28 27 5 Steel (cast) 7.QIQ I Q56 26 5 I.QOI 27 I I 7Q2 25 6 Iron 7.757 2.O7Q 26.8 2,188 31.2 I,77O 25.2 The metric values are in thousands of kilogrammes per square centimetre; the British in millions of pounds per square inch. 273. The Stress produced by Change of Temperature is easily calculated when the modulus of elasticity and the coefficient of expansion are known, thus : Let E = the modulus of elasticity ; A = the change of length per degree and per unit of length ; Af the difference of initial and final temperatures; / the stress produced. 31 482 MATERIALS OF ENGINEERING NON-FERROUS METALS. Then: / : E : : A Af : i, .-./ = \EAf (i) For good wrought iron and steel, taking E as 28,000,000 pounds on the square inch, or 2,000,000 kilogrammes on the square centimetre, and A. as o. 0000068 for Fahrenheit, and as 0.0000120 for Centigrade degrees : 190 Af Fahr., nearly } . . . . (2) = 25 At Cent., nearly ) For cast iron, taking E = 16.000,000; 1 = 0.0000062 : p 100 Af Fahr., nearly , , , = 12 Af Cent., nearly ' ' ' This force must be allowed for as if a part of the tension, T, or compression, C, produced by the working load when the parts are not free to expand. 274. Sudden Variation of Temperature has an effect, very usually, upon the non-ferrous metals, which is afterward seen in a permanent alteration of their properties. Repeated heating and cooling causes a permanent change of form, and sudden cooling from high temperatures causes a modification of the tenacity and ductility of the kalchoids and the metals composing such alloys, which is precisely the opposite of that produced on steel. Thus copper, brass, and bronze, suddenly cooled from a low red heat, are softened and weakened and greatly improved in malleability and ductility. This process, which is one of hardening and tempering with steels, is thus one of softening with other metals. On the other hand, very slow cooling softens or " anneals " steels, while it hardens the non-ferrous metals and alloys. Thus, also, casting bronze ord- nance or other castings in chills increases the value of the metal by preventing liquation and securing homogeneousness and maximum density. CONDITIONS AFFECTING STRENGTH OF ALLOYS. 483 275. The Effect of Chill-casting is exhibited in the fol- lowing tables of tests by tension furnished to the Author by the U. S. N. Department in the course of a series of investi- gations in 1877. The metal has the composition, copper (Lake Superior), 9 ; tin, I ; it was cast either in chills or in sand as specified, after having been melted in a reverberatory furnace, the copper first and the tin three hours later. The specimens tested were of the " short " pattern, and the reduction of sec- tion, rather than the elongation recorded, is the measure of relative ductility. The tables also exhibit the method of testing usual in the Ordnance Department of the U. S. Navy in 1875-6. British measures are here used. TABLE LXXXVIII. EFFECT OF CASTING BRONZE IN "CHILLS.' Navy Ordnance- Bronze. TENSILE I b. O 98 i~i STRENGTH PER Z cr. H OHO S w R g SQUARE INCH OF Sg Sg s H MARK. S - H , 13 . lc I s ! H O y sl 0* fl < Z C S2 HC li SPECIF] Mi, 3-4-75 M 2. ^-4-75 BB IX 3 22,385 70,000 71,600 .100 .40 417 Full of large tin spots. M 2, 5^75 No. 3, 8-21-75 .. No. 2, 8-21-75 .. 45,737 49,77 2 48,000 65,600 60,000 .2603 .211 470 .240 .20 8 878 Cast in chill mould. Cast in chill mould. GB 2, 5-6-75... GB 3, 5-6-75 R 3 L, 12-70-7=;. M i C, 3-11-76 . B 2 C, 3-11-76.. B 3 C, 3-11-76.. lg]8rt 5i'v459 39,000 91,600 73,450 71,600 4075 .0291 !s8o .396 415 50 .438 .376 373 8 392 8853 Flaw in the breaking portion. Cast in chill mould. (.ast in chill mould. Cast in chill mould. The guns cast in chill moulds were composed of 10 parts of copper to I part of tin ; the others were of o parts of cop- per to i part of tin. In the course of experiments made by Major Wade,* three * Report on Ordnance. 484 MATERIALS OF ENGINEERING NON-FERROUS METALS. howitzers, Nos. 27, 28, and 29, were cast from the same liquid metal. No. 27 was cast when the metal was at the highest temperature, No. 28 was cast fifteen minutes later, and No. 29 fourteen minutes after No. 28. The following results were obtained : K s Z 27 28 9 TIME OF METAL IN LADLE, MINUTES. TEMPERATURE OF METAL AT CASTING. SPECIFIC GRAVITY TENACITY Of gun- heads. Of entire gun. Of small bars cast in Of gun- heads. Of small bars cast in Gun mould. Separate mould. Gun mould. Separate mould. O 15 2 9 Highest . . . Mean Lowest 7.986 8.351 8.538 8.195 8.551 8.752 8.686 8.823 8.816 8.554 8.447 8.376 17,761 28,995 23,722 50,973 52,330 56,786 31,^32 28,153 28,082 In casting another howitzer, No. 30, small test-bars were cast in separate moulds, one of which was of cast iron, to ascertain the effect of sudden cooling, and the others were of clay, similar to the gun-mould. The tests of all the samples from this casting were as follows : SPECIFIC GRAVITY. TENACITY. Small bars cast separately in iron mould. . Small bars cast separately in clay mould. . Small bar cast in gun mould 8-953 8.313 8.806 37,688 25,783 C7 708 Gun-head samples 8 J.QO qc 78 Finished howitzer 8. T\II The effect of the chill is evidently very beneficial, and iron moulds should, therefore, always be used where possible in the casting of bronze ; with brass they are less necessary. 276. Effect of Tempering and Annealing. Riche de- termined the effect of tempering and annealing upon the CONDI TIONS A FFE C TING S TRENG TH OF ALLO YS. 48 5 density of the bronzes, finding that tempering increased the density of those rich in tin but not of others, as gun-bronzes ; and that annealing reduces the density of tempered bronze although it does not entirely destroy that effect. Density is increased to a considerable degree by mechanical action as well as by tempering. Successive temperings and annealings produce, on the whole, an increase of density. Tempering, according to both Darcet and Riche, softens the bronzes rich in tin, i.e., those containing about 20 per cent. tin. Thus, Riche obtained the result that such bronzes, tempered, can be moulded in the press, while they will crack if untempered or annealed. Bronze and steel exhibit opposite behavior in this respect. The same author finds that working hot does not increase the density more than working at low temperature. The metal increases in density very rapidly by working hot, and without danger of rupture ; while cold the action is ex- tremely slight and very difficult. There is evidence that the method of making gongs by the Chinese involves working hot under the hammer.* Riche, reaches the following conclusions : f "The bronzes rich in tin (18 to 22 per cent.) increase in density with tempering; and annealing lessens the density of tempered bronze, but in a less proportion. The density is considerably increased by the alternate actipn of tempering and annealing, and of the press. These effects, tne reverse of those in steel, coincide with the fact that tempering softens bronze while it hardens steel. " This softening, discovered by Darcet, is not sufficient to allow of this bronze being worked cold for industrial pur- poses. It was shown that this metal extremely hard when cold and pulverizable at red heat is forged and rolled at dark red heat with remarkable facility. This fact enabled me, in common with M. Champion, to succeed in the manu- facture of tamtams, and other sonorous instruments, by the method followed in the East. * Industries Anciennes, etc. Lacroix, Paris, 1869. \ Annales de Chimie et de Physique, vol. xxx., 1873. 486 MATERIALS OF ENGINEERING NON-FERROUS METALS. " Tempering produced no apparent softening in the bronzes less rich in tin (12 to 6 per cent.); and if they are tempered for industrial uses it is more especially in order to detach the oxide produced during the reheating of the matter in the course of the operations. " It was found that in the axis of a cannon, and especially toward the muzzle, there are some parts very rich in tin and in zinc. " The density of copper, subjected alternately to me- chanical action, then to tempering or annealing, displays in- verse variations according as it is exposed to the air or sheltered from it during the reheating; while in the first case the mechanical action increases the density, in the second mechanical action diminishes the density. " Mechanical action* increases the density of yellow brass, and this effect is counteracted in part by tempering, and especially by annealing. It is thought that annealing is pref- erable to tempering in working with brass. " Mechanical action, tempering, and annealing, do not sensibly change the volume of similor and of the bronzes of aluminium, alloys remarkable for the facility with which they can be worked. " While repeated mechanical action increases the density of the bronzes rich in tin, especially of porous copper, of copper alloyed with iron, of brass, it evidently diminishes the density of copper exposed to the air during reheating, and it produces no noticeable alteration in the volume of similor or of aluminium bronze. Tempering produces on brass, and especially on the bronzes rich in tin previously annealed, an increase in density, contrary to what takes place in steel, cop- per and glass. " It will be perceived that tempering diminishes the density of a body, because the surface, cooled before the centre, cannot contract freely by reason of the resistance that the interior parts dilated at this moment offer to con- traction." The following are some of the results of Riche's experi- ments. CONDITIONS AFFECTING STRENGTH OF ALLOYS. 487 BRASS. DEN SITY. I. II. After rolling 8.4OQ 8 412 After tempering 8 410 8 /ITT After rolling 8 4i4 8 4IS 8.4-11 8427 After rolling U..+JJ. 8 447 8 416 After tempering 8 433 o.^ju 8416 8 410 84/M 8.4-37 8 417 After rolling 8 .no 8417 After tempering 8 44^ 8 441 The metal was a yellow brass containing copper, 65 ; zinc, 35. The same general effect was seen when the brass con- tained, copper, 91 ; zinc, 9. It is to be noted that there is a great difference between the effect on copper protected from the air while heating it, as should always be done, and on copper exposed to the air ; annealing and tempering diminished density in the one case and increased it in the other, although the latter modification is not important. The increase of density resulting from the heat is very nearly compensated by the tempering, so that the plate, after being made considerably thinner, is found to have the same density as before the operation. Cast at a high temperature, the density became 8.939, in Riche's ex- periments, and was but 8.039 when poured at a low heat. 277. The Effect of Annealing on Tenacity is seen in the following experiments : Wertheim obtained for the tenacity of copper wire, T. Tm. ELON. 58,600 4,100 0.0033 45,100 3,160 0.0030 488 MATERIALS OF ENGINEERING NON-FERROUS METALS. Kirkaldy, testing wire, obtained the following results : TABLE LXXXIX. TENACITY OF WIRE, HARD AND ANNEALED. COMPLETE TURNS < H HARD WIRE (A). ANNEALED WIRE (E). IN 5 IN. (12.8 gfl CM.). 0^ ^ Lbs. per Kilogs. Lbs. per Kilogs. A. B. ^ sq. in. persq. cm. sq. in. per sq. cm. E h Phosphor-bronze . 102,750 7,224 49*351 3-470 6. 7 87 37-5 i 120,957 8,504 47,787 1,360 22.3 52 34-1 f a 120,950 8,503 53,381 3-753 13.0 124 42.4 ' * l 139,141 9,872 54,153 3,807 17-3 53 44-9 i t( 159.515 11,212 58,853 4,138 13-3 66 46.6 ' " i5i,H9 IO,625 64.569 4.340 15-8 60 42.8 Copper. 63 1 22 A A OS 77 002 2 6O2 86.7 96 34-i Steel 1 2O 076 8 506 74. 6^7 5,248 22.4 79 10.9 Best charcoal iron. 65,834 4,629 46,160 3,245 48.0 87 28.0 These figures are considerably in excess of those or- dinarily obtained for bronzes into which no phosphorus has been introduced. The effect of annealing is remarkably great. Other illustrations of this and related phenomena are given elsewhere, as, e.g., in Art. 247, where they are well ex- hibited in Anderson's experiments on sterro-metal. 278. The Effect of Temperature of Casting and cool- ing upon zinc has been studied by Bolley as illustrative of this effect generally.* He finds that zinc may solidify in either of two forms, the one finely crystalline, the other coarsely crystalline with lamellar structure. He finds these conditions to be determined, not by the presence of other elements, but by the temperature of casting. When cast at the lowest temperature at which it will " pour," it takes the first form, v/ith a density of 7.18; when cast at a full red heat, it takes the second form, with a lower density, 6.86. In the first case, it is comparatively malleable, remains malle- able throughout a wide range of temperature, and is not as readily soluble in acids as when in the second condition. In * Annalen der Chimie und Pharm., xcv,, p. 294. CONDITIONS AFFECTING STRENGTH OF ALLOYS. 489 the latter form it is not malleable, and is more soluble. These conditions have not been studied with other metals. 279. The Effect of Time, and Velocity of Rupture, on the action of stress is not less important with the non- ferrous than with the ferrous metals. A very important difference is found to exist between the two classes. (See Part II., Art. 295, et seg.) The rupture of the non-ferrous metals takes place under lower stresses, as the time of oper- ation is greater, and the fracture is more slowly produced. The contrary is the case with iron and steel. With non-ferrous metals, the piece strained may give way, ultimately, under static loads greatly less than those required to produce im- mediate rupture. This occurs to a less extent with soft annealed iron, and still less with harder irons and steels. Cast iron is stated by Hodgkinson to be capable of sustain- ing, indefinitely, loads closely approaching the breaking load under test. Some of the alloys will probably exhibit similar differences. With rapid distortion, the resistance is increased with non-ferrous metals, decreased with iron. The Author has, therefore, enunciated a principle which had been deduced from experiments on wrought iron, which is, evidently, of vital importance to the engineer, viz. : " That the time during which applied stress acts is an important ele- ment in determining its effects, not only as an element which modifies the effect of the vis viva of the attacking mass and the action of the inertia of the piece attacked, but also as modifying seriously the conditions of production and relief of internal strain by even simple stresses." * Should it be true, as suggested by the Author, that the cause of the variation of resistance, sometimes observed with increased velocity of distortion, is closely related to the cause of the variation of the elastic limit by strain, f it would seem to be a corollary that materials so inelastic and so viscous as to be incapable of becoming internally strained during dis- tortion, should offer greater resistance to rapid than to * Trans. American Society of Civil Engineers, vol. iv., p. 334. f See Part II., pp. 588-604; figures 135-138. UNIVERSITY 490 MATERIALS OF ENGINEERING NON-FERROUS METALS. slowly-produced distortion, in consequence of their inability to " flow " so rapidly as to reduce resistance by such fluxion at the higher speed, or by correspondingly reducing the fractured section. This principle has been shown, by a large number of experiments, to be frequently, if not invariably, the fact. Copper, tin, and other inelastic and ductile metals and alloys, were found by the author to exhibit this behavior, and are therefore quite opposite in this respect to commercial wrought iron and worked steel. The records of the Mechanical Laboratory of Sibley Col- lege, Cornell University, frequently illustrate the proposition that metals which gradually yield under a constant load offer increased resistance with increased rapidity of rupture. The curves of deflections of a considerable number of ductile metals and alloys are very smooth when the time dur- ing which each load has been left upon them is the same ; but whenever that time has been variable the curve has been irregular. Bars of such metals broken by transverse stress give a greater resistance to rapidly increasing stress than to stress slowly intensified. Two pieces of tin, as described in Article 280, were broken by tension, the one rapidly and the other slowly. The first broke under a load of 2,100 and the latter of 1,400 pounds. The example illustrates well the very great difference which is possible in such cases, and seems to the writer to indicate the possibility, in extreme cases, of obtaining results which may be fatally deceptive when the time of rupture is not noted. The depression of the elastic limit has been observed pre- viously in materials, but less attention has been paid to it than the importance of the phenomenon would seem to demand. The strain diagram of a bronze bar is nearly hyperbolic ; but the law of Hooke, ut tensio sic vis, holds good, as usual, up to a point at which the load is about one-half the maximum. The curve of times and loads exhibits the rate of loss of effort while the bar was finally held at a deflection of 0.5456 inch, the load being carefully and regularly reduced, as the effort diminished, from 1,233 to 9 11 pounds, at which latter figure the bar broke. The curve is a very smooth one. CONDITIONS AFFECTING STRENGTH OF ALLO YS. 49! TABLE XC. EFFECT OF TIME ON BRASS. BAR NO. 599. 90 parts zinc, 10 parts copper : i x 0.992 x 22 inches. i | i LOAD. I SET. LOAD. SET. LOAD. 1 SET. z h a a Pounds. Inch. Inch. Pounds. Inch. Inch. Pounds. Inch. Inch. 23 0.0033 363 0.0781 _ 43 o 0881 , $ - 63 0.0127 3 0.0079 803 * 103 0.0225 0.031 403 Resistar 0.0886 ce fell in fi h. 30 m. 1,003 I,IO3 0.3178 0.3921 163 Resistan to 143 0.0347 ce fell in i 0.0347 5 h 25 m. to 333 o.c886 0.0896 0.0246 I,20 3 Resis 0.481 ance fell i 0.0039 Resis tance fell i n 15 h 163 0.0391 to 302 0.0896 .5209 20} 0.0471 33 o 0876 243 0.0544 403 0.1072 i 233 0. HA tift 0.0611 503 0.1282 J-TJ 323 0.0692 6o| 0.1521 The bar was left under strain at n h 22 A.M., and the effort to restore itself measured at intervals, as follows : HOUR. 11:37 11:50 A.M. 12:2 EFFORT. 1,133 1,093 ^070 At i h 23 P.M. the bar broke. 12:8 1,063 12:25 1,043 12:39* 1,023 12:53* 1,003 12:58* i:20 P.M. 993 911 pounds. BAR NO. 596. 75 parts zinc, 25 parts copper ; second casting- ; 0.985 x 0.985 x 22 inches. . z 2 2 o o LOAD. w SET. LOAD. 1 SET. LOAD. i SET. B E s! H Q S Pounds. Inch. Inch Pounds. Inch. Inch. Pounds. Inch. Inch 23 0.0057 463 0.0799 503 .0894 63 0.0142 503 0.0866 543 .0952 . 103 0.0207 3 0.0014 583 .1012 $ 0.0275 0.0346 5 lesi S 0.0866 tance fell in 5 h. 623 .1042 .1075 ; III 303 $ 423 0.0414 0.0485 0.0549 0.0610 0.0669 0.073 to 489 Resistar to 473 3 0.0866 o!o866 ce fell in i 0.0866 0.0074 3 h. 30 m. 0.0092 643 .1102 663 .1136 Broke 5 seconds ringing sound. after with An example of somewhat similar behavior, but exhibited by a metal of very different quality, is shown above. 49 2 MATERIALS OF ENGINEERING NON-FERROUS METALS, This bar was hard, brittle, and elastic, but must ap- parently be classed with tin in its behavior under either con- tinued or intermitted stress. These latter specimens were broken ; one in each set by adding weight steadily until the end of the test, so as to give as little time for elevation of elastic limit as was possible ; and one in each set by intermittent stress, observing sets, and the elevation of the elastic limit. There seems to the Author to exist a distinction, illus- trated in these cases, between that " flow " which is seen in these metals, and that to which has been attributed the relief of internal stress and the elevation of the elastic limit by strain and with time. If the long-known effects of cold-hammering, cold-rolling, and wire-drawing in stiffening, strengthening, and hardening some metals can be, as the Author is inclined to believe, at- tributed in part to this molecular change, as well as to simple condensation and closing up of cavities and pores, this vari- ation of the elastic limit by distortion under externally ap- plied force has been shown to occur in iron and in metals of that class in tension, torsion, compression, and under trans- verse strain. 280. Effect of Prolonged Stress on Tin and Zinc. In testing a bar of tin, in work done as described in earlier chap- ters, the Author studied this phenomenon. An experiment on No. 29 A (a bar of pure tin) was made to determine the difference in resistance to slow and rapid rupture. This bar was a good casting, and tests of the two pieces, one from the upper and one from the lower end of the bar, should show little, if any, difference in strength. No. 29 A was tested with a load of 1,700 pounds, which caused an elongation of 0.15 inch. This load was then reduced to 1,250 pounds, and the reading again taken, showing an elongation of 0.19 inch, which increased in two minutes to 0.27 inch. The load was then increased to 1,400 pounds, and the elongation was 0.32 inch. The load was allowed to remain on the bar for ten minutes, and the elongation gradually increased to 1.7 inches, when the bar broke. It seems probable from this test that CONDITIONS AFFECTING STRENGTH OF ALLOYS. 493 the load of 1,400 pounds would have broken the piece, even if the load of 1,700 pounds had not been placed on it at the beginning of the test. Bar No. 29 B was tested in a different manner. The load was gradually, but rapidly, increased to 2,100 pounds, with- out stopping longer than was necessary to take the reading 494 MATERIALS OF ENGINEERING NON-FERROUS METALS. of the elongations at 975, 1,180, 1,290, 1,600, and 2,000 pounds. At 2,100 pounds, the elongation read 1.88 inches. The piece then extended very rapidly, and, at the same time, its resist- ance, as measured by the scale-beam, reduced to 1,700 pounds. The pump of the hydraulic press was worked as fast as pos- sible, but the beam could not be balanced beyond 1,700 pounds. The piece sustained this load a few seconds, then broke after an elongation of 2.58 inches. Comparing the tests, it is seen that the resistance of No. 29 A to an elongation greater than 0.19 inch was never greater than 1,400 pounds, while that of No. 29 B was 2,100 pounds, or 50 per cent, more than the former ; which 50 per cent, ap- parent increase of strength was evidently due to the greater rapidity of the test of No. 29 B. The fact that the difference in strength is only apparent is confirmed by the experiments by torsional stress on pieces from the same bar. These showed that torsion-pieces No. 29 A and No. 29 B, from the top and from the bottom of the bar, tested by moderately slow motion, each gave a resistance of 14.2 foot-pounds tor- sional moment ; piece No. 29 C, from the middle of the bar, tested in the same manner, resisted 13.2 foot-pounds, while No. 29 D, a piece taken from the middle of the bar and ad- joining No. 29 C, tested by very slow motion and left under stress for hours, resisted only 9.2 foot-pounds or some 30 per cent, less than either of the other pieces. The effect of slow and rapid test is shown by both bars in the tensile test. The average tenacity of all the pieces tested is given as 3,130 pounds per square inch, but it is probable that all the pieces would have broken at as low as 2,000 pounds if the test had been of long duration, say one hour, or as high as 4,000 pounds if each test had been made in, say, five minutes. The records of several tests follow. The effect of time is also shown in the autographic strain- diagrams (Fig. 30), and in the records calculated from them. CONDITIONS AFFECTING STRENGTH OF silLOYS. 4Q5 TABLE XCI. STRENGTH OF TIN AS VARYING WITH TIME OF TESTING. Tests by Tensile Stress. QUEENSLAND TIN, CAST. No. 58 A. Material : Tin cast in iron mould. Dimensions : Length, 5" (12.7 cm.) ; Diameter, 0.798" (2 cm.). LOAD PER SQUARE INCH. ELONGATION IN 5 INCHFS. i ELONGATION IN PARTS OF ORIG- INAL LENGTH. LOAD PER SQUARE INCH. ELONGATION IN 5 INCHES. 8 ELONGATION IN PARTS OF ORIG- INAL LENGTH. Pounds. e soo 1,000 240 1,200 1,400 1,6:0 1,800 2,000 240 2,000 2,000 DO for 14 mm Minutes. i 2 3 4 I 7 Inch. 0.0002 0.0027 0.0081 0.0175 0.0303 0-0433 0.0517 0.0630 0.0745 o!o86o unds per sqt utes, elongati 0.1070 0.1156 0.1298 0.1*37 0.1580 0.1709 0.1861 Inch o 0159 o 0756 are inch ke on increasing .00004 .0005 .0016 0035 Minutes. 8 9 10 ii Inch. 0.1997 0.2176 0.2328 0.24(yO Pounds. .0062 .0086 .0103 .0126 .0149 .0172 3t constant \ as follows: 13 14 Resistai square int side. i,703lbs. i min. Resistai broke 2 in The fr boundary measured Tensile section, u kilogs. pe Total ti 0.2929 0-33" ice reduced h, and a crac 0.3610 0.4315 ice decrease ches from A actured suri nearly ellif 0.580 and o.c strength pe nder slow st r sq. cm.), me of test, 3c to 1,700 p< k was obseri d gradually, end. ace had an >tical ; two 85 inch. r square inc rain, 2,000 p minutes. mnds per /ed on one .0722 .0863 and piece irregular diameters i, original ounds (141 No. 58 B. 400 0.0005 .OOOI Stress kept constant for 2 minutes. 600 O.OO29 % m ,OOo6 i mm. i 0.0724 ...... .0^45 800 0.0051 .0010 2 min. I 0.0821 .0164 1,000 O.OIOS .0022 Increased stress rapidly for i minute, and 1,200 1,400 0.0184 0.0293 0037 .0059 piece broke at 3,520 pounds per square inch. Total time of test, 8 minutes. 1, 600 . .0079 Diameter of fractured section, 0.542 inch. 1,800 0.0484 0097 Tensile strength per square inch, original 2,000 0.0566 .0113 section under rapid strain, 3,520 pounds (248 240 0.0557 kilogs. per sq. cm.). 2,000 0.0631 .0126 49$ MATERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XCL Continued. TEST BY TRANSVERSE STRESS. N 0t 58. Material : Queensland tin cast in iron mould. Dimensions : / = 22" (55.9 cm.) ; b i" (.2.54 cm.) ; d i" (2.54 cm.). w m in u in j. 1 2 < J W g Z w II s| Sg II ii ^g O H D 3 2 o 2 3 H PH M 52 J H z o J H H M in o O Q s H ^ en Q O S Pounds. Inch. Inch. ^^. Inch. 7M. 10 0.0082 Resistance decreased in 8 minutes to 56 20 0.0118 5i574i99 J pounds. 0009 100 0.3033 10 0.0087 no 0.3827 O.OI2Q I2O 0.6403 3 0.0173 5,310,020 130 0.8091 40 0.0241 5^35:593 Cont'd f-x-07 5 0.0333 0126 3i59 i7 4 i min. i 7 60 70 80 0.0502 0.0600 0.0859 140 till deflec 1.36 Ran pressi .ion was mo ire-screw do re than 3 in wn slowly ches ; the o. 1416 scale-bear n vibratinsr all the time about 150 100 3 0.2109 pounds. Bent without breaking. o 1753 100 0.2415 Breaking load, P 150 pounds. Resistance decreased in i minute to 70 pounds. Modulus of rupture, R VTJJ = 4?5S9 Resistance decreased in 3 minutes to 62 pounds. (metric, 321). The effect of prolonged stress on cast zinc is exhibited by the following memorandum of test : No. 21 (cast zinc). Four pieces were tested by torsion, which gave results nearly agreeing, the torsional moments varying from 34.42 to 37.83 foot-pounds, and the angles of torsion from 123 to 163 degrees. The strain diagrams of these pieces exhibit marked peculiarities. No. 21 D was left for fourteen hours under stress, just before reaching its maxi- mum resistance. In this time the resistance decreased 15 per cent. On resuming the test, the piece slowly resumed its maximum resistance, which it held for some time. It was then left under stress, and in about 30 seconds the resistance decreased about 15 per cent. The piece then broke partly through, and the resistance decreased to less than one-half the maximum. On continuing the torsion, the piece held by the unbroken side exhibited a constant resistance till it CONDITIONS AFFECTING STRENGTH OF ALLO YS. 497 was twisted through about 80 degrees further, when it broke entirely across. On No. 21 B experiments were made to determine the effect of rapid and of slow stress and of resting under stress. They indicated a decrease of resistance when resting under stress, a uniform resistance to very slow motion, and a rapid increase of resistance to rapid motion, except after the resist- ance has reached the maximum, when rapid motion then keeps the resistance constant. It was observed that very ductile metals, such as tin itself and alloys containing a large amount of tin, all exhibit different amounts of resistance to slow and to rapid stress, and a decrease of resistance on resting under stress. The same phenomenon is exhibited by cast zinc, which is much less ductile than the copper-tin alloys, and is less ductile than several of the alloys of copper and zinc (those contain- ing from 20 to 40 per cent, of zinc), which either did not show the phenomenon at all, or but slightly. 281. The Effect on Bronze of long continued stress in producing continuous distortion, even when the loads are far within those required to produce the same effect on first application, is well exhibited below. TABLE XCII. EFFECT OF TIME ON BRONZE. Tests by Transverse Stress With Dead Loads. Samples i x i x 22 inches. \ MATERIAL PARTS. fr- it O LOAD. DEFLEC- TION. TIME. INCREASED DEFLEC- BREAKING WEIGHT. 6 "Z Tin. Copper. Pounds. Inches. Inches. Hounds. I 1.9 100 08.1 600 475 o-534 1.762 5 minutes . . 3 minutes . . 0.009 0.291 650 9 7.2 92.8 So 950 2.108 0.348 3 minutes . . 5 minutes . . 0.488 0.081 500 i,35o 10 10. 90. 1,485 o-395 3-447 5 minutes . 13 minutes . . 0.021 4.087 i",485 ii 90-3 9-7 100 0.085 10 minutes . . 0.021 120 0.140 10 minutes . . 0.055 140 O.22I 10 minutes .. 0.098 .... 140 o 319 10 minutes . . 0.038 I 4 o 357 40 hours . . . 0.920 .... 32 MATERIALS OF ENGINEERING NON-FERROUS METALS. ' TABLE XCIL Continued. 3 MATERIAL PARTS. | k LOAD. DEFLEC- TION. TIME. INCREASED DEFLEC- BREAKING WEIGHT. 5 i Tin. Copper. Pounds. Inches. Inches. Pounds. 160 1.294 10 minutes . . . 0.025 160 1.320 i day I . OOO .... 160 2.320 i day I. 000 160 3.320 i day i. ooo 160 2 98.89 i. ii 90 0.243 5 minutes . . . 0.063 120 0.736 15 minutes . 1.055 120 1.791 30 minutes . . . 0.748 I2O 2-539 45 minutes 0.595 120 3- I 34 12 hours 8.000 1 20 3 100 80 0.218 5 minutes 0.064 no Metals having a composition intermediate between these extremes have not been observed to exhibit flow or to in- crease deflection under a constant load. The same phenomena are exhibited by tests made in the autographic testing machine,* thus : \ MATERIAL. & TIME UNDER STRESS. OF TOR- SION. FALL OF PENCIL. REMARKS. 2 Tin. Cop- per. tl 40 hours . . . 65 0.06 inch.. . Recovered after further distortion of i. t? 100 i hour ,80 o.i inch... Recovered in 8. fo 280 4 99-44 c. S 5 12 minutes . $380 50 per cent. Did not recover. 98 8i' i ii 6 Alloy. 58 0.2 inches. Did not recover. Tests by tension with similar materials exhibit similar results, and these observations and experiments thus seem to indicate that, under some conditions, the phenomena of flow, and of variation of the elastic limit by strain, may be co- exist^pt, and that progressive distortion may occur with " viscous " metals. 282. A Fluctuation of Resistance with Time, illustrated in the table here given, is a singular phenomenon which has been observed by the Author, but the causes of which remain Part II., p. 379. f Same piece. Taking " elasticity line." CONDITIONS AFFECTING STRENGTH OF ALLOYS. 499 TABLE XCIII. FLUCTUATION OF RESISTANCE. Test by Transverse Stress. ALLOY OF COPPER AND TIN. No. 47. Material : Alloy. Original mixture: 17.5 O, 82.5 Sn. Dimensions : Length between supports, 22''; Breadth, 0.996"; Depth, 0.983". LOAD. DEFLEC- TION. A SET. MODULUS OF ELASTICITY. PP LOAD. DEFLEC- TION. A SET. MODULUS OF ELASTICITY. PP 4 A Id 3 4 A bd* Pounds. 10 20 40 60 80 IOO 5 120 Ifo 180 2OO 5 200 220 240 2fo 270 280 200 300 Thetx reading Th? h poise till Time : Inch. 0.0027 o . 0070 0.0153 0.0256 0.0365 Be 0.0499 0.0617 o. 1042 0.1343 0.1666 Inch. In 2 pounds back ti and anc Pounds. Beam In 2 c In 10 In 39 Rant again a In 4 In 23 Inih at 20 po Ranb again a To 5 tal utes 0.3 Repla 280 300 Breal Modul minutes more, beam balanced at 14 The pressure-screw was then run .1 beam balanced again at 5 pounds, ther reading of set taken. Inches. Inch. 0.20i8 im sinks slo\ 0.0092 0.0821 8,039,339 7,356,258 6,594,770 6,167,163 v\y. 5,638,814 rose again, ttinutes balai minutes bala minutes bala ack pressure : 5 pounds. ainutes beam minutes beai our and 36 unds. ack pressure i. 5 pounds. decrease ofi 084 0.2^45 ced load of : 0.4849 0.5332 Broke on a .ing load, 3cx us of ruptur< iced at 10 po need at \t p( need at 23 pc -screw till be 0.2902 rose again, n balanced a minutes bea -screw till be 0.2845 et in 2 hours = 0.0239 incl 280 pounds. unds. mnds. unds. am balanced 5,472,481 4,899,597 4,320,565 3,77^245 3,377,873 1 14 pounds, m balanced am balanced and 20 min- i. 0.1798 0.2145 0.2503 0.3021 0.3367 0.3762 0.4147 0-4597 ;am was obse of set was tal earn rose ag beam balan< minutes. 2,697,980 832,406 0.3084 rved to rise, cen in 2 min' 0.3022 ain, pushed :ed at 10 pou and another ites. I pplying strain. > pounds. *, R T"JO ~ 10,288. forward the nds. No. 48. Material: Alloy. Original mixture: 12.5 Cu, 87.5 Sn.- Dimensions : Length between supports, 22"; Breadth, 0.985"; Depth, 0.990". . 10 o 0025 Scale beam rose. 20 0.0050 In 2 minutes balanced at 20 po unds. 80 0.0141 0.0230 0.0752 Bes m sinks siov 7,901,458 7,249,195 6,330,144 rly. In 4 minutes balanced at 29 pounds. In 15 minutes balanced at ;u pounds. Ran back pressure-screw till beam balanced again at 5 pounds. IOO 5 0.0508 0.0120 5,482,803 5 I 0.6555 Beam rose again, balanced at | 12 pounds in 120 0.0760 4,397,784 5 minutes. 140 0.0969 4,024,116 5 0.6508 160 0.1262 ...'.'.. Total decrease of set in 20 minutes, 0.6742 1 80 0.1592 .'...' 0.6508 = 0.0234 inch. 200 0.2044 \[ 2,725,307 Beam rose again, but test was continued 5 0.1238 without further waiting. 200 (X2268 260 o 8704 220 o 2016 280 o 0018 240 260 y " 0.4078 O ^2IO 1,639,194 300 1.0760 Beam sank rapidly. 300 Repeated. Bar broke iust as beam 270 x o. 5703 rose. 280 9' x 0.6458 1,207,609 Breaking load, 300 pounds. 2OO 0.7185 vyi 300 0.8025 1,041,220 Modulus of rupture, R = ~TJ^ = = 10, 254. 5 0.6742 500 MATERIALS OF ENGINEERING NON-FERROUS METALS. to be determined. The bars tested as shown were not per- fect in structure, and do not exhibit any considerable strength ; they consist principally of tin (82.5 and 87.5 per cent.) and are valueless for the ordinary work of the constructor, although useful " white metals." It is seen that the resistance of both bars was, at times, overcome by the load, but, on balancing the weigh-beam, the bar each time gradually re-acquired a power of raising the load which had deformed it, and straight- ened itself sufficiently to raise the beam against the upper " chock." A decrease of set took place of 0.02 inch in the first beam in two hours and twenty minutes, and in the second in twenty minutes. In two minutes, recovery occurred to such an extent that the bar exerted an effort of 20 pounds tending to straighten itself, and in 15 minutes of 34 pounds. The phenomenon is one which will demand careful investi- gation. 283. The Effect of Unintermitted and Heavy Stress on Resistance is well exhibited on the two sets of strain-dia- grams* here reproduced from Part II. of this work. The first series of tests exhibited decrease of resistance with time No. 655 was a bar of Queensland tin, presented to the Author by the Commissioner of that country at the Centen- nial Exhibition, and which was found to be remarkably pure. A load of loo pounds gave a deflection of 0.2109 inch, and produced a set of 0.1753 inch. The same load restored de- flected the bar 0.241 5 inch, which deflection being retained, the effort to regain the original shape decreased in one min- ute from 100 to 70 pounds, in 3 minutes to 62, and in 8 min- utes to 56 pounds. The original load of 100 pounds then brought the deflection to 0.3033 inch, nearly 50 per cent, more than at first. A bar, No. 599, of copper-zinc alloy, similarly tested, deflected 0.5209 inch under 1,233 pounds, and took a set of 0.2736 inch after being held at that deflection 15 minutes, the effort falling meantime to 1,137 pounds. Restoring the load of 1,137 pounds, the deflection became 0.5131 inch, and the original load of 1,233 pounds brought it to 0.5456 inch. * Trans. American Society of Civil Engineers, 1877. CONDITIONS AFFECTING STRENGTH OF ALLOYS. 5OI The bar was now held at this deflection and the set gradually took place, the effort falling in 15 minutes to 1,132 pounds (4 per cent, more than at the first observation), in 22 minutes to 1,093, in 46 minutes to 1,063, in 63 minutes to 1,043, m gi}4 minutes to 1,003, an< ^ m IJ 8 minutes to 911 pounds, at which last strain the bar broke 3 minutes later, the deflection remaining unchanged up to the instant of fracture. This remarkable case has already been referred to in an earlier article, when treating of the effect of time in producing varia- tion of resistance and of the elastic limit. Nos. 561, copper-tin, and 612, copper-zinc, were composi- tions which behaved quite similarly to the iron bar at its first trial, the set apparently becoming nearly complete, in the first after i hour, and in the second after 3 or 4 hours. In all of these metals, the set and the loss of effort to resume the original form were phenomena requiring time for their progress, and in all, except in the case of No. 599 which was loaded heavily the change gradually became less and less rapid, tending constantly toward a maximum. So far as the observation of the Author has yet extended, the latter is always the case under light loads. As heavier loads are added, and the maximum resistance of the material is approached, the change continues to progress longer, and, as in the case of the brass above described, it may progress so far as to produce rupture, when the load becomes heavy, up to a limit, which closely approaches maximum tenacity in the " iron class." The brass broke under a stress 25 per cent, less than it had actually sustained previously. The records are herewith presented, and the curves repre- senting them shown in the figures which follow. 502 MA TERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XCIV. DECREASE OF RESISTANCE AND INCREASE OF SET OF METALS, WITH TIME. Bars i inch square ; 22 inches between supports. TIME. LOAD. LOSS OF LOAD. DEFLECTION. SET. TIME. LOAD. LOSS OF LOAD. DEFLECTION. SET. No. 6 4 WROUGV T IRON. First Trial. , Min. Pounds. Pounds. Inches. Inch. Min. Pounds. Pounds. Inches. Inch. 1,003 0.0995 3 0.1091 w 3 0.0049 1,603 0.287 ..... 1,003 .. '. O.IOOI I '82 0.287 25 999 4 O.IOOI 2 1,493 no 0.287 IOO 12 O. IOOI 3 1,483 1 20 0.287 275 OS/ 16 O. IOOI 23 1,463 140 0.287 320 987 16 O.IOOI 53 1,461 142 0.287 320 3 o 007 133 T ,459 144 0.287 322 987 0.9910 193 i,457 146 0.287 322 1,003 o. 1003 363 146 0.287 2,720 ... i 2 . 6400 363 3 0.148 1,457 0.2863 Second Trial. ,^ ji i 603 o. 3016 L i uu o 2,720 2.6400 ..... 1,003 2 2548 | 96.5 993 240 0.5456 No. 561. 27.5 PARTS COPPER, 72.5 PARTS TIN. 118 9" 322 121 911 326 1 Broke ..... 160 0.0696 5 0.0145 No. 6l2. 47.5 PARTS COPPER, 52.5 PARTS ZINC 160 0.072 I 154 "6 0.072 8co 0.3332 3 150 10 0.072 3 0.1478 2,640 104 56 0.072 808 0.3366 4,140 IOO 60 0.072 5 790 10 0.3366 5 . . . ! 0.04 25 778 22 0.3366 -' IOO 160 320 0.0763 ; 0.0970 ; 0.2200 , Broke 120 4 80 1,320 766 756 75* 34 44 49 0.3366 0.3366 0.3366 No. 599. 10 PARTS COPPER, 90 PARTS ZINC. 75i ::: 0.3364 o. 1688 800 0.3490 ,233 0.5209 1,100 Broke 15 , T 37 0.5209 3 o 2736 No. 655. QUEENSLAND TIN. ,137 0.5131 .... ,233 0.3456 IOO 0.2109 IS ,133 IOD 0.5456 3 0.1753 28 ,093 140 0-5456 IOO 0.2415 4 46 63 ,070 ,063 ,43 I6 3 170 I 9 o-545 5 0.5456 0.5456 :::: i 7 62 56 30 44 0.2415 0.2415 0.2415 77-5 ,023 210 0.5456 IOO 1,003 230 OT-O 0.5456 150 o. 3^33 Bent rapidly. 284. The Observed Increase of Deflection Under Static Load. In the preceding article the writer presented results of an investigation made to determine the time required to CONDITIONS AFFECTING STRENGTH OF ALLOYS. 503 produce " set " in metals belonging to the two typical classes, which exhibit, the one exaltation, and the other a depression of the elastic limit under strain. The experiments there described were made by means of FIG. 31. DECREASE OF RESISTANCE WITH TIME. Rate of set of Bars i inch square 22 inches between supports. a testing-machine, in which the test-piece could be securely held at a given degree of distortion, and its effort to recover its form measured at intervals, until the progressive loss of effort could no longer be detected, and until it was thus in- dicated that set had become complete. The deductions were : That in metals of all classes under light loads this de- 5O4 MATERIALS OF ENGINEERING NON-FERROUS METALS. crease of effort and rate of set become less and less notice- able until, after some time, no further change can be observed, and the set is permanent. That in metals of the " tin class," or those which had 'been found to exhibit a depression of the elastic limit with intermitted strain, under a heavy load, i. e., a load consider- ably exceeding the proof strain, the loss of effort continued, until, before the set had become complete, the test-piece yielded entirely. And that in the metals of the " iron class," or those exhibiting an elevation of elastic limit by strain, the set be- came a maximum and permanent, and the test-piece remained unbroken, no matter how near the maximum load the strain may have been. The experiments here described were conducted with the same object as those above referred to. In these experi- ments, however, the load, instead of the distortion, was made constant, and deflection was allowed to progress, its rate being observed, until the test-piece either broke under the load or rapidly yielded, or until a permanent set was pro- duced. The results of these experiments are in striking accordance with those conducted in the manner previously described. They exhibit the fact of a gradually-changing rate of set for the several cases of light or heavy loads, and illustrate the striking and important distinctions between the two classes of metals even more plainly than the preceding. The accompanying record and the strain-diagrams, which are its graphical representation, will assist the reader in compre- hending the method of research and its results. All test-pieces were of one inch square section, and loaded at the middle. The bearings were 22 inches apart. No. 65 1 was of wrought iron from the same bar with No. 648.* This specimen subsequently gave way under a load of 2,587 pounds. Its rate of set was determined at about 60 per cent, of its ultimate resistance, or at 1,600 pounds. Its de- flection, starting at, 0.489 inch, increased in the first minute, 0.1047; in the second minute, 0.026; in the third minute, * Trans. Am. Soc., C. E., vol. v., page 208. CONDITIONS AFFECTING STRENGTH OF ALLOYS. 505 0.0125; in the fourth minute, 0.0088; in the fifth minute, 0.0063; and in the sixth minute, 0.0031 inch; the total de- flections being 0.5937, 0.6197, 0.6322, 0.641,0.6473, and 0.6504, inch. In the succeeding 10 minutes the deflection only increased 0.0094 inch, or to 0.6598 inch, and remained at that point without increasing so much as o.oooi inch, although the load was allowed to remain 344 minutes untouched. The bar had evidently taken a permanent set, and it seems to the writer probable that it would have remained at that deflection indefinitely, and have been perfectly free from liability to fracture for any length of time. This bar finally yielded completely, under a load of 2,589 pounds, deflecting 4.67 inches. No. 479 was a bronze bar containing 3^ per cent, of tin. Its behavior may be taken as typical of that of the whole " tin class " of metals, as the preceding illustrates the behavior of the " iron class " under heavy loads. It was subjected to two trials, the one under a load of 700 and the other of 1,000 pounds, and broke under the latter load, after having sus- tained it \y hours. The behavior of this bar will be con- sidered especially interesting, if its record and strain-diagram are compared with those of No. 599, previously given, which latter specimen broke after 121 minutes, when held at a con- stant deflection of 0.5456 inch ; its resistance gradually falling from an initial amount of 1,233 pounds, to 911 pounds at the instant before breaking. This bar, No. 479, was loaded with 700 pounds " dead weight," and at once deflected 0.441 inch. The deflection increased 0.118 inch in the first five minutes, 0.024 in the second five minutes, 0.018 in the second ten minutes, 0.17 in the fourth, 0.012 in the fifth, and 0.008 inch in the sixth ten minute period, the total set increasing from 0.441 to 0.65 inch. The record and the strain-diagram show tha<- at the termination of this trial the deflection was regularly increas- ing. The load was then removed and the set was found to be 0.524 inch, the bar springing back 0.126 inch on removal of the weight. The bar was again loaded with 1,000 pounds. The first 506 MATERIALS OF ENGINEERING NON-FERROUS METALS. deflection which could be measured was 3.118 inches and the increase at first followed the parabolic law noted in the pre- ceding cases, but quickly became accelerated ; this sudden change of law is best seen on the strain-diagram. The new rate of increase continued until fracture actually oc- curred, at the end of ij^ hours, and at a deflection of 4.506 inches. This bar was of very different composition from No. 599 ; it is a member of the " tin class," however, and it is seen, by examining their records and strain-diagrams, that these specimens, tested under radically different conditions, both illustrate the peculiar characteristics of the class, by similarly exhibiting its treacherous nature. No. 504 was a bar of tin containing about 0.6 per cent, of copper the opposite end of the scale and exhibited pre- cisely similar behavior, taking a set of 0.323 inch under no pounds and steadily giving way and deflecting uninterruptedly until the trial ended at the end of 1,270 minutes, over 2t hours. This bar, subsequently, was, by a maximum stress of 130 pounds, rapidly broken down to a deflection of 8.11 inches. No. 501 presents the finest illustration of this phenomenon yet met with by the Author. The test extended over nearly / 2 days under observation, and the bar left for the night was found next morning broken. The time of fracture is there- fore unknown, as is the ultimate deflection. The record is, however, sufficient to determine the law, and the strain- diagram is seen to be similar to that of the second test of No. 479, exhibiting the same tendency to the parabolic shape and the same change of law and reversal of curvature preceding final rupture, and illustrates, even more strikingly, the fact that this class of metals is not safe against final rupture, even though the load may have been borne a considerable time, and have apparently been shown, by actual test, to be capable of sustaining it. A strain-diagram of each of the latter two bars is exhibited on a reduced scale to present to the eye more strikingly this important characteristic. A comparison of the records and the strain-diagrams with CONDITIONS AFFECTING STRENGTH OF ALLOYS, 5O/ those of the preceding article, in illustration of the behavior of the two classes of metals under constant deflection, is most FIG. 32. INCREASE OF DEFLECTION WITH TIME. Rate of Set of Bars i Inch Square 22 Inches Between Supports. instructive. It will still be necessary to make many experi- ments to determine under what fraction of their ultimate resistance to rapidly applied and removed loads, the members of the " tin class" the viscous metals will be safe under static permanent loads. The records in Table LXXXIII., Art. 267, present many illustrations of the phenomenon here considered. 508 MA TERIALS OF ENGINEERING NON-FERROUS METALS. TABLE XCV. INCREASE OF DEFLECTION WITH TIME. Bars, i inch square ; 22 inches between supports. Load applied at the middle. z o INCREASE. INCREASE. H 5 TIME. 3 TIME. 3 H Q Difference. Total. i Difference. Total. No. 651. WROUGHT IRON. Min. Inches. Inches. Inches. 30 0.618 0.017 0.177 Load, i, 600 pounds. 40 0.630 O.OI2 0.189 Min. o Inches. 0.4890 Inches. Inches. 5 60 0.642 0.650 0.012 0.008 0.201 0.209 i 0.5937 0.1047 0.1047 Set 0.524 2 0.6197 0.0260 0.1307 3 0.6322 0.0125 0.1432 Second Trial. Load, 1,000 pounds. 4 0.6410 0.0088 o. 1520 0.6473 0.0063 0.1583 3.118 6 0.6534 0.0031 0.1614 5 3.540 0.422 0.422 16 0.6598 0.0094 o. 1708 3.660 0.120 0.542 544 0.6598 o.oooo Maximum load, 2,589 pounds; deflection, 4.67 inches. 0.1708 maximum 45 Broke 4.102 7-634 bar under i, 0.442 3.522 ooo pounds. 0.984 4.506 No. 504. 0.557 PARTS COPPER, 99.443 PARTS TIN. No. 501. 9.7 PARTS COPPER, 90.3 PARTS TIN. o Load, no pounds. 323 o Load, 1 60 pounds. . 294 5 .406 0.083 0.083 10 .319 0.025 0.025 845 945 1-539 1.622 70 .463 0.144 o. 169 865 .005 0.059 1.681 130 530 0.067 0.236 895 .138 o.i34 1.815 310 .691 0.161 0.397 1,025 .248 o. no 1-925 400 .766 0.075 0.472 1,110 .378 0.130 2.055 460 .811 0.045 0.517 faaxin deflectio 2.626 lum load, i n, 8. ii inche 0.248 30 pounds; 5. 2.303 maximum ,360 ,475 ,565 -534 .697 .782 0.723 0.163 0.085 1.240 1.403 1.488 '730 938 0.156 1.644 ,880 3.136 0.198 1.842 No. 479. 96.27 PARTS COFFER, 3.73 PARTS TIN. ,780 ,940 3.798 4.274 0.662 0.476 2.504 2.980 Load, 0.441 foo ponnds. 3,000 3,295 Bar 1< 4-349 5-097 ;ft under st 0.075 ain at nierh 3.055 3.803 t and found 5 0-559 0.118* 0.118 broken in the morning. IO 0.583 0.024 o. 142 20 0.601 0.018 0.160 285. Depression of Elastic Limits. The effects of inter- mitted stress and of interrupted strain are of peculiar interest and importance with the non-ferrous metals and the alloys. So far as they have been observed by the Author, they are often precisely the opposite of those noted in experiments on merchant iron and commercial grades of steel. They are well illustrated in Fig. 33, which is here reproduced from Part II. CONDITIONS AFFECTING STRENGTH OF ALLOYS. 509 These strain-diagrams are obtained by transverse test, from bars of common iron, Nos. 648, 649, 650, 651, and from two specimens of bronzes, Nos. 596, 599, all of the same size, 9-9 Btl I inch (2.54 cm.) square and 22 inches (55.9 cm.) between sup- ports. The first strain diagram to be studied is that of a bar of the most ductile metal (No. 599, copper, 10; zinc, 90). It exhibits clearly the phenomenon of flow with a depression of the elastic limit under constant load. 5IO MATERIALS OF ENGINEERING NON-FERROUS METALS. ' This bar was left deflected under a load of 163 pounds (74 kgs.). It gradually lost its power of restoration until it only exhibited an effort of 143 pounds (65 kgs.). The curve exhibits the relation of deflection to deflecting force. The resistance gradually increased as deflection progressed until the load 403 pounds (183 kgs.) produced a deflection of 0.09 inch (0.23 cm.). The bar was again left, and, under a fixed deflection, again lost resisting power, and the effort to straighten itself fell to 333 pounds (151 kgs.). Finally, the bar offered its maximum resistance of 1,233 pounds (560 kgs.) under a deflection of 0.545 inches (1.3 cm.), and was then held in its flexed position. Gradually its effort to restore itself grew less and less, until, when it had fallen to 911 pounds (414 kgs.), the bar suddenly snapped and the two halves fell to the floor. No. 596 (copper 25, zinc 75) similarly exhibited a depres- sion of the elastic limit by strain, but, vastly harder, more elastic and brittle, it broke under 663 pounds (301 kgs.) and at a deflection of o.i 136 inch (0.3 cm.), before apparently pass- ing the point termed the primitive or apparent limit of elastic- ity by the Author, i.e., that point at which the sets become nearly proportional to the strains, and at which the line of the strain-diagram turns sharply away from the vertical. The strain-diagram No. 648, common iron, is that of the type of that class in which the elevation of the elastic limit has been detected by the Author. The bar was like the preceding, of I inch (2. 54 cm.) square section and 22 inches (55.88 cm.) in length between bearings. It reached its elastic limit at 1,450 pounds (659 kgs.) and at a deflection of 0.15 inch (0.4 cm.). Pass- ing this point, and at a deflection of 0.287 inch (0.7 cm.), the bar was held at a constant deflection, under a load of 1,600 pounds (727 kgs.). Flow occurring, the effort to regain its original shape became less and less, until in six hours it had fallen to 1,457 pounds (662 kgs.). Continuing the test, re- sistance and deflection increased as indicated by the curve, instead of following the original direction. Similar increase of resisting power under strain is seen at CONDITIONS AFFECTING STRENGTH OF ALLO VS. 5 1 1 other points on the curve, and whenever the process of dis- tortion was interrupted long enough to permit flow and that re-arrangement of particles which has been described. An hour or two usually gave time enough to bring out this re- markable phenomenon. This action has been discovered in iron and steel, and under every form of strain tension, torsion, compression and cross-breaking and it would seem that aside from accidental overstrain, producing incipient rupture or loss of strength due to such action as abrasion or corrosion, length of life of iron structures under strain was in itself, apparently, a source of increased safety. On the other hand, as is here seen, the be- havior of non-ferrous metals is precisely the opposite, and the engineer is compelled to use them with greater caution and to base his calculations upon a higher factor of safety, a conclusion fully corroborated by the work of Wohler. Recurring to Fig. 33, a resemblance is to be noted in the behavior of both classes of metals. The bars No. 649, 650 and 65 1 were tested by rapidly in- creased load up to the breaking point, allowing no time for reading of sets. The first of this set deflected 0.014 inch (0.04 cm.) under IOO pounds (45 kgs.), 0.052 under 500 pounds, 0.098 under 1,000 pounds, and 0.18 under 1,500 pounds. At 1,600 pounds the deflection was 0.2854 inch, and the bar yielded to the stress, and the deflection became 0.363 in 2^ minutes. Under 1,640 pounds the deflection increased in six minutes from 0.383 to 0.440 inch, and a maximum resistance was recorded of 2,350 pounds (1,070 kgs.), and a deflection of 5.577 inches (15 cm.). This bar was tested in a similar manner to the preceding, and in the same machine. Numbers 650 and 651 were tested by dead loads i.e., by laying upon them heavy weights. By this method the deflection could increase to a maximum under each load, in- stead of being kept constant, as in the testing machine. No. 650 was rapidly broken without allowing time for completion of set or any considerable exaltation of the elastic limit. The plotted curves of results exhibited well the striking difference 512 MATERIALS OF ENGINEERING NON-FERROUS METALS. of behavior between this bar and 651, which was purposely given time for set and for exaltation of the elastic limit. At 1, 500 pounds (682 kgs.) each had deflected nearly the same amount, and had passed the elastic limit, as usually called. The first, however, gave way completely with 2,260.5 pounds (1,027 kgs.), while the second, after several times exhibiting an elevation of the elastic limit as at 1,500, 1,600, 1,700, 1,900, 2,300, 2,400 and at 2,500 pounds finally only yielded entirely at 2,589. The first only deflected 2^ inches (7 cm.); the second, 4.67 inches (11.9 cm.); although when the latter was loaded with about the weight at which the first yielded, it deflected about the same amount. The last bar was left two and a half days under its final load, and its deflection increased from 4.275 inches (109 cm.) to 4.67 (11.9 cm.), when the weights reached the supports of the frame and the test was ended. The other bar sank rapidly after being loaded with 1,600 pounds (726 kgs.). Both classes of metals, when flexed, were shown to exhibit less and less effort to restore themselves to their original form. In the case of the tin class, as the Author has called it, this continues indefinitely. With the iron group this loss of effort gradually becomes less and less and reaches a limit at which the bar is found to become stronger than at first. The two classes are thus seen to be affected by time in precisely the same manner initially, but finally in exactly opposite ways. 286. The Effect of Variable Stress in causing variation of the normal series of elastic limits observed during ordinary tests is well shown by the records of test of the copper-zinc alloys. The following are extracts from the memoranda taken during tests made for the U. S. Board to which fre- quent references are made. Similar illustration may be found among the records of tests, both of bronzes and of brasses, already given. Bar No. 8 (60.94 copper, 38.65 zinc) bent to a deflection of 3^2 inches under a load of 1,140 pounds. The apparent elastic limit was reached at about 640 pounds. At 400 pounds the bar was left under stress for eighteen hours, at the CONDITIONS AFFECTING STRENG TH OF ALLO YS. 5 1 3 end of which time the scale-beam was found still balanced, the resistance to a constant deflection being unchanged. At 800 pounds the scale beam dropped and the resistance de- creased 1 8 pounds in one hour. After leaving the bar under a stress of 800 pounds for one hour, taking the reading of a set, then applying a stress of 840 pounds, the deflection was 0.0185 inch over the deflection produced by 800 'pounds. The load was increased to 880 pounds, and the deflection increased 0.441 inch. An ad- ditional 20 pounds then increased the deflection only 0.020 inch, and another 20 pounds only 0.0515 inch. Successive additions of 20 pounds at a time were applied, and the in- creased amounts of deflection were as follows : 0.22, 0.07, 0.20, 0.09, 0.25, o. 10, 0.25, o.io inch. The time occupied in applying the load was as regular as possible, about 30 seconds. This irregularity of resistance to distortion has been also observed both in tensile and torsional tests of pieces obtained from the same bar, and of other bars of nearly similar composi- tions. Bar No. 10 (49.66 copper, 50.14 zinc) broke at a load of 940 pounds after a deflection of 1.257 inches. The weakness was due to unfavorable conditions of casting. 'The fractured sur- face showed a finely porous or spongy surface, and the com- position was not homogeneous. The limit of elasticity was passed at 320 pounds. At 200 pounds the scale beam was observed to sink very slowly. After 200 pounds had been applied, a slight crackling sound like the " cry of tin " was heard to proceed from the bar, which continued for two or three minutes, while the de- flection was held constant by the pressure-screw. After it had ceased to be distinctly audible it could be heard on ap- plying the ear to the bar. With every increase of load the same phenomenon took place till the bar broke. After 940 pounds had been applied, slight cracks were heard and the scale-beam dropped. The poise was pushed back and the beam balanced at 580 pounds. No crack could be perceived in the bar, and no indication of fracture. After reading the deflection the pressure was then taken off the bar MATERIALS OF ENGINEERING NON-FERROUS METALS. and a reading of set taken. The pressure was again gradually applied, and when it reached 500 pounds the bar broke. The sudden decrease of resistance from 940 to 580 pounds without visible appearance of breaking cannot be explained. The crackling sound emitted by the bar during the whole test after passing a load of 200 pounds, and when it was held at a constant deflection for several minutes, is evidence of molecular change, probably the " flow of metals " described by Tresca. Bar No. 11 (47.56 copper, 52.28 zinc) behaved much like No. 10, but was much stronger, breaking at 1,360 pounds. The elastic limit was passed at 450 pounds. At 460 pounds the scale-beam sank about 16 seconds after it balanced. At 560 pounds a crackling sound was heard from the bar like that emitted from bar No. 10, which continued for 10 minutes, gradually growing fainter. With the same deflection, the re- sistance decreased 50 pounds in 15 hours. On proceeding with the test the next day, the crackling sound was again given out by the bar, and continued till the bar broke at 1,360 pounds, after a deflection of 1.17 inches. Bar No. 19 (10.30 copper, 88.88 zinc) was similar in charac- ter to other bars containing a large proportion of zinc, but was stronger, sustaining a load of 1,233 pounds before rupture. It broke, however, at 911 pounds, two hours after it had sus- tained the load of 1,233 pounds. The total deflection before breaking was 0.5456 inch. The record of this test is given in full in the tables, and is entirely unlike that of any other bar tested. Three " time tests" were made at 163,403, and 1,233 pounds, which showed the common phenomenon of decrease of resistance with time. In the last case the resistance de- creased from 1,233 to i, 137 pounds in fifteen minutes. After taking a reading of the set, the load of 1,233 pounds was again applied and the decrease of resistance with time noted at intervals during a period of two hours. The decrease of resistance was at first rapid, 100 pounds in the first fifteen minutes, and then much slower. In the fifteen minutes, commencing at one hour and three minutes after the beginning of the " time test," the decrease was 20 Or THfc- UNIVERSITY CONDITIONS AFFECTING STRENGTlF'#j? pounds ; in the next fourteen minutes the decrease was again 20 pounds. In the five minutes, commencing one hour and thirty-two minutes after the " time test," the decrease was 10 pounds, showing an increase of the rate of decrease. Another observation was twenty-two minutes, when the rate was found to have largely increased, the decrease of resistance in these twenty-two minutes being 82 pounds. In three minutes after taking the last reading, when it balanced at 911 pounds, the bar suddenly broke without warning. The deflection was unchanged during this entire " time test." The elastic limit was reached at about 900 pounds. 287. The Effect of Repeated Strain is greater with the non-ferrous metals, and usually with the alloys, than with iron and steel. The investigations of Wohler and Spangenberg were made principally upon the latter class of materials, but were also made to cover the action of a few other metals. Wohler's law, that the rupture of a piece may be pro- duced by the repeated action of a load less than that which, once applied, would cause fracture, is true, probably, of all the non-ferrous metals, and this effect is with them much more serious than with the ferrous metals. Spangenberg found that gun bronze in tension would endure a stress of 22,000 pounds per square inch (1,547 kgs. per sq. cm.) laid on and at once removed 4,200 times before rupture; a stress of 16,500 pounds (1,160 kgs.) 6,300 times, and 11,000 pounds per square inch (773 kgs. per sq. cm.), 5,547,600 times. It may be con- sidered safe under indefinitely repeated loads falling well under one-half its tenacity as determined by ordinary test. Phosphor bronze, forged, bore 53,900 repetitions of the small- est of the above loads, and 2,600,000 of the next load, but broke under 1,621,000 repetitions of a load of 13,750 pounds per square inch (967 kgs. per sq. cm.). The cast metal sus- tained 408,350, 2,731,161 and 2,340,000 repetitions of the same loads. This peculiar behavior is not explained by the experimenter. Further experiment in this direction is desirable. Mean- time, the engineer will probably find it advisable to allow, for intermittent loads, but one-half the stresses which would be 5l6 MATERIALS OF ENGINEERING NON-FERROUS METALS. permitted for single applications of load, and one-quarter where suddenly applied, while the factor of safety should be probably not less than one-half greater for non-ferrous material than with iron. The limits of stress sometimes pro- posed are not far from the following, which may be compared with the values already given for factors of safety and ulti- mate strength. TABLE XCVI. PERMISSIBLE REPEATED STRESSES FOR NON-FERROUS METALS. . FACTOR OF SAFETY. MAXIMUM STRESS. Dead Load. Live Load. T\ JI Load. Load. Lbs. per Kgs. per Lbs. per Kgs. per sq. in. sq. cm. sq. in. sq. cm. Copper, cast 4 8 "> OOO <7C2 2 ^OO 176 4 ' forged ... 8 15 ooo I O<^ 7 ^OO 528 '* wire A 8 16 ooo I 12^ 8 ooo 56-* Gun-bronze, cast 4 8 10,000 703 5,000 352 Brass, yellow, cast . . . 4 8 5,000 352 2,500 176 rolled . 4 8 10,000 703 5,000 352 " wire . . 4 8 12,000 845 6,000 423 Lead, rolled 4 3 1,000 70 500 35 When the stresses are reversed, as in connecting rods, the factor of safety should be doubled and the maximum stresses reduced at least one-half. CHAPTER XIV. MECHANICAL TREATMENT OF THE METALS.* 288. Qualities Affected by Mechanical Treatment* The metals used by the engineer in construction, as they are found in the market, and often when they have been given the form and dimensions desired in the finished piece, are known to be liable to exhibit certain defects and to possess certain peculiar characteristics. Some of these defects are removable by proper mechanical treatment, and some of the characteristic qualities may be modified in a marked manner by special methods of manipulation. All known and actually practised methods of so altering the character of the metals used by the engineer, involve, directly or indirectly, the ele- vation of the original elastic limit of the material; and they usually produce a change, more or less marked, in the ultimate strength, the elasticity, the resilience in fact, in all the physical properties of the metal. The subject of the mechanical treatment of metals has already been considered, incidentally, and to a very limited extent, in Part II. of this work.f It is intended, in the pres- ent chapter, to describe successful and established methods at some length, when they have not already been so described. The effect of mechanical treatment is due to that change of volume, density, and condition of molecular aggregation which is produced by any action causing flow while under stress, and, especially, while under compression.^: This action is sometimes, as in wire drawing, incidental to the process of * Principally from an article contributed to the Metallurgical Review, 1877. f Part II., 48, 165, 178, 191, pp. 71, 196* 262 328 \ Part II., Chapter X. 5l8 MATERIALS OF ENGINEERING NON-FERROUS METALS. manufacture, and sometimes, as in the Whitworth or Jones systems of compressing ingot metal, and as in the cold-rolling process, an independent operation. Mechanical treatment does not directly modify the chem- ical composition of the metal, and is, therefore, incapable of changing, either for better or worse, the nature of the mate- rial, so far as it is determined by the chemical constitution. So important, however, are the modifications which can be effected by mechanical treatment, and so extensively are they likely to be applied in the arts, that a more extended and a more precise analysis than can be here given would be re- quired to do full justice to the subject. All defects removable by mechanical treatment may be properly classed as defects involving want of homogeneous- ness. Metals maybe homogeneous in two ways : (i.) They may be homogeneous in structure i.e., they may be free from such defects as blow-holes, which are generally numerous in cast metals, and from the cinder streaks which produce the fibre in rolled and forged iron ; the molecules of the several constituents of which they are composed are then uniformly distributed ; (2.) The metal may be homogeneous as to strain i.e., it may be free from such stresses as are known often to exist in badly designed castings of brittle materials like hard cast iron, speculum metal, and in glass. Defective homogeneousness of structure maybe removed, more or less completely, at any temperature below that of fusion, by methods specially adapted to use at the given tem- perature. Blow-holes are probably due to the presence of air and of other gases, either absorbed from the atmosphere, as illus- trated in the " spitting " of silver, or developed by chemical actions occurring within the mass of metal while in a state of fusion. This gas can be condensed, excluded or expelled, either by the mechanical act of compression, or by the use of some material in the form of a flux, which shall either prevent the development or the absorption of the gas, or which shall unite with it, forming a compound which can be separated by the usual process of skimming the molten metal in the MECHANICAL TREATMENT OF THE METALS. 519 melting pot, or which shall, if retained in the mass, be less injurious than the free gas. The latter process is illustrated in the use of silicon and of manganese to confer soundness upon the cast ingots in the Bessemer and other processes of steel making, and by the use of phosphorus in insuring soundness in the better class of copper-tin and of copper-zinc alloys, which metals are very liable to be made seriously defective by the absorption of oxygen and the formation of oxide. The bronzes especially, when rich in copper, are exceedingly liable to this kind of defect, and the immense increase in the tenacity, ductility, and other valuable qualities of such alloys, which may be ob- tained by securing perfect soundness by such removal of the cause of their unsoundness, has only recently been made gen- erally known. The density of yellow copper (65 copper to 35 tin) is in- creased by working it mechanically. Mechanical action, chilling, etc., usually produce no perceptible change in the volume of pinchbeck, an alloy of 91 copper to 9 zinc, or in aluminium bronze, both of which are remarkable for the ease with which they may be wrought. 289. The Whitworth Process. The mechanical treat- ment of metal at the point of fusion, for the purpose of securing homogeneity of structure, is illustrated by the Whit- worth process of making compressed steel. In all the usually practised methods of making steel, the metal is cast in ingots, which are subsequently hammered or rolled into any desired shape. The steel is sometimes poured into moulds and given working shapes like cast iron; the resulting shapes are known in the market as " steel castings." These ingots or castings are very liable to contain blow- holes or air cells, which are produced by the retention, while solidifying, of occluded air and bubbles%f disengaged carbon monoxide originating in the oxidation of a portion of the carbon previously united with the metal. The lower the per- centage of carbon present, the greater the injury produced in this manner. The use of manganese is resorted to for the purpose of preventing this " piping ; " but as it is used in the 52O MATERIALS OF ENGINEERING NON-FERROUS METALS. form of a carbide, it is usually found difficult to use a sufficient quantity of manganese in the " milder" steels without, at the same time, introducing too much carbon. Silicon, also, has been found to possess the same property in an even higher degree than manganese. One or two one-hundredths of one per cent, has been said to reduce liability to such porosity very greatly. At Terrenoire, France, the double silicide of iron and manganese, instead of spiegeleisen, is added to the molten metal as a carburizer. In large castings and ingots, also, the internal strains, in- duced by the contraction of the inner portions after the external part of the mass has solidified, produce serious weakness, and often crack the whole body of metal to such an extent as to entirely destroy its value. This is peculiarly liable to occur in hard steels. Such steels are entirely unfitted for the use of the engineer in construction ; and such metal is only used for tools. The " low " steels, on the contrary, possessing great strength, combined with great ductility, are the best known metals for constructive purposes. The cast metal, for the reasons already stated, is usually worthless for immediate application ; but could it be produced free from porosity, and as dense as the forged steel, it would have equal strength and ductility, and would be equally applicable foi use in structures ; it would also have the important advan- tages of cheapness and of facile production in any desired shape. This result is said to have been very perfectly secured at Terrenoire by the method of fluxing above alluded to. Whitworth secures this condition by subjecting the fluid steel to very heavy pressure while contracting and until com- pletely solidified, by the use of the hydraulic press. A pressure of 20 tons to the square inch produces all of the compactness, density, strength and ductility of a forging. By this method, Whitworth has, in place of worthless metal as castings produced steel of tenacities varying in the several grades from 80,000 pounds per square inch to 150,000 pounds, and of ductility varying from 35 per cent, in the softer metal to 14 per cent, in the strongest grade. Guns made of the softest grade, when burst, do not fly in pieces as cast guns, MECHANICAL TREATMENT OF THE METALS. 521 invariably, and even wrought-iron guns very generally, do, but simply open along the line of minimum strength, and thus explode with comparative safety to the gun's crew. FIG. 34. WHITWORTH'S PRESS FOR INGOT METAL. Metal shown to the Author by Sir Joseph Whitworth, in 1870, at Manchester, England, as a product of this process, was very remarkable for its strength, ductility and homogeneous- ness, and worked under the tool with most admirable freedom and uniformity. Whitworth states that the column of fluid steel, while solidifying under pressure, shortens an inch and a half to 522 MATERIALS OF ENGINEERING NON-FERROUS METALS. each foot of its length. The fact is a good index of the value of the process, and gives some idea of the degree of unsoundness of the best of ordinary castings. The change Enlarged Section through A, A. Vertical Section. Horizontal Section through B, B. FIG. 35. INGOT CAST WITHOUT PRESSURE. of texture due to compression is very marked, as shown in the accompanying engravings * and is readily observed by the nost inexperienced eye. The only special precaution de- manded in the use of this method is to so arrange the plant that the molten steel may be put under pressure before * From Whitworth on Guns and Steel. ME CHA NIC A L TREA TMEN T OF THE ME TALS. 523 solidification has commenced ; the requisite strength of moulds must also be secured.* 290. The Lavroff Process. Bronze and brass may be treated by the same methods which are seen to have been so successfully adopted in working steel, and with no less im- portant gain in excellence of quality. These compositions are peculiarly liable to defects arising from the occlusion of gas and by the formation of oxide within the mass. Copper has a very great affinity for oxygen at high temperatures, and the very best of copper-tin and of copper-zinc alloys, if made Transverse Section of Steel Ingot Transverse Section of Steel Ingot Cast in the Ordinary Way. Compressed while in a Fluid State. FIG. 36. INGOT. without special provision against such injury, are seriously defective from these causes. The strongest piece of such composition which the author has ever made, and which far exceeded in tenacity any gun metal or any other metal approximating to the same composition, was visibly and keenly defective. Treatment with phosphorus, or other oxygen-absorbing element, has been found to do much toward correcting this fault. Could a perfect absorption of oxygen be effected, the almost invariable unsoundness of bronze and * See Report on Machinery and Manufactures at the Vienna International Exhibition, 1873, by the Author. Washington, 1875. Page 439. 524 MATERIALS OF ENGINEERING NON-FERROUS METALS. brass castings would probably be prevented, and what would now be thought a remarkable combination of strength and ductility would be secured. Muschenbroeck gives the tenacity of fine copper wire at about 90,000 pounds to the square inch (6,327 kgs. per sq. cm.). Cast copper rarely reaches a tenacity of 20,000 (1,406 kgs). Yet, with maximum density and perfect purity, the one should be as strong as the other. Compression with proper fluxing will do all that can be done toward giving castings of these metals a maximum of strength, ductility and resilience. Colonel LavrofT, of the Russian army, has applied the Whitworth method to the making of cast bronze guns. To make the process thoroughly complete, it is only necessary that the metal compressed should have been previously purified by effective fluxing be- fore pouring. Col. Lavroff, as stated by Col. Laidley in his ordnance notes (No. xl., printed by the Ordnance Bureau of the United States War Department), places the flask, in which the gun is to be cast, in a pit directly beneath the cylinder of a hydraulic press. The upper end of the flask 'is closely capped by a strong plate of iron, having a cylindrical hole in its centre. Through this opening a plug of sand is forced down upon the molten metal by the hydraulic press, and enters the mass of fluid bronze two inches or more, producing the required degree of condensation. With such pressures as are employed for steel, the improvement in the quality of bronze would be expected to be quite as marked as in that metal. 291. Rolling and Forging". Compression and " work- ing" metal in the solid state, but at high temperature, is the most usual method of not only giving the materials of con- struction their shape, but also of improving their valuable qualities. As is well known to every engineer, all the metals are found to gain strength with hammering and rolling. The strength of a grade of iron which has a tenacity of 50,000 pounds per square inch of section, when macje into bars two inches in diameter, becomes gradually increased as the size of the bar is reduced by rolling, until a one-inch bar of the MECHANICAL TREATMENT OF THE METALS. $2$ same iron is found to have a tenacity of nearly or quite 60,000 pounds to the square inch. Copper and some of the alloys may be similarly improved by heating to a moderately high temperature and drawing out under the hammer, or in the rolling mill. Cast copper, of a tenacity of 20,000 pounds per square inch, acquires in this way a strength of 40,000 pounds and upward. 292. Hydraulic Forging and Drop Forging. This process is not always effective, however, as large masses, both welded and cast, are very liable to contain cavities, even after having been subjected to the most skilful manipulation in the forge or the rolling mill. The most effective system of ham- mering is likely to prove inefficient, where applied to large pieces, in consequence of the fact that the inertia of the mass attacked will often cause the effect of the blow to be felt only near the exterior, the internal portions remaining after treat- ment nearly as spongy and as irregular in structure as before. The comparatively moderate, but pervading there is no bet- ter word effect of the heaviest hammer, is best adapted to do such work. The best of all methods of securing thorough condensation, in the process of forging small pieces which can be so treated, is that in which the hydraulic press with its slow action, producing an effect which is felt throughout the entire volume of the piece, is employed. This process has been well developed by Mr. R. L. Haswell, at Vienna, and is fully de- scribed by Prof. W. P. Blake in his report on iron and steel at the Vienna Exhibition of 1873.* The process of making forging, with the " drop press," which has attained greatest perfection in this country, and in which the piece is shaped in a die by a single heavy blow, is also thoroughly satisfactory as applied to small pieces. The system of hydraulic forging is most economical of power, as it has been shown by Prof. Kick that the loss of power, wherever shock is employed in such work, is serious. It is wasted by dispersion in all directions in the form of heat, due to compression and to directly produced tremor of molecules, * Reports of the U. S. Commissioners to Vienna International Exhibition, 1873. Washington, 1876. 4 vols. 8vo, pp. 3,500. 526 MATERIALS OF ENGINEERING NON-FERROUS METALS. and in the jar and shake which affects all neighboring masses. The quiet, steady action of the hydraulic press accomplishes the desired change of form without the latter kind of loss of energy, and with a minimum loss of power from the produc- tion of heat by molecular motion. 293. Thermo-Tension and Annealing. Defects of homo- geneousness of structure may thus be removed, partially or wholly, by several known processes of treatment of heated metal. Defect of homogeneousness as to strain is removable from iron, and perhaps from other metals, by annealing and by a method called in 1836, by its discoverer, Prof. Walter Johnson, " thermo-tension." The metal is heated to a full red heat, but with great care to avoid a temperature so high as to give rise to danger of serious reduction of strength by approaching the welding heat. At this elevated temperature it is subjected to a tensile stress of as great intensity as is safe. The metal is then allowed to cool, retaining the stress applied, and when cold it is released. Prof. Johnson found this process to confer upon the iron experimented with a maxi- mum resistance to change of form exceeding, by about 16 per cent., that which it had originally possessed. He offered no explanation of the molecular change to which the effect noted was due ; but it has been attributed by the Author to a release of internal strains which had previously been introduced by the irregularly produced flow of the metal occurring during the processes of manufacture. Cast metals, glass, and other materials which have been given form by fusion, casting in moulds and solidification which so occurs as to produce irregular contraction and a con- sequent unsymmetrical distribution of metal, and which are, therefore, found to be weakened by the presence of internal strains, are relieved of such internal strain by the familiar process of annealing. The more brittle the material, the more carefully and slowly must the process of annealing be conduct- ed. The more ductile the metal and the greater the freedom with which it is found to " flow" under the action of applied forces, the less serious are these strains, and the less important is the process of annealing. MECHANICAL TREATMENT OF THE METALS. $2? 294. Cold Working. Metals are worked perfectly cold in some cases, and the several methods of treatment at the ordinary temperature may be divided into two classes : (i.) Those which are practised for the purpose, simply, of conferring greater density, and of thus securing homo- geneousness of structure. (2.) Those which are adopted for the purpose of modify- ing the character of the metal in respect to internal strains, and thus of altering the normal elastic limit of the material by the intermittent application of external forces. Cold working is illustrated in the processes of wire draw- ing, cold hammering and cold rolling, simple compression, and simple extension of metal without heating. The effect of either of the processes involving compression will assign the process to the one or the other of the two classes, according to the nature of the material. It may be that the same remark will be found applicable to all methods of cold working. 295. Wire Drawing. The process of wire drawing is the oldest and most generally familiar of these methods of treat- ment of the useful metals. In the manufacture of wire, the metal is rolled down into rods a quarter of an inch or less in diameter, which rods are called " wire rods." These rods are then, in the wire mill, drawn through holes in steel plates, each of which holes is slightly smaller in diameter than the wire to be passed through it. As the wire is reduced in size, it gradually becomes hardened, and, at intervals, the process is interrupted, and the metal is subjected to the process of an- nealing to soften it, and thus to enable the decrease in size to be carried on without the serious loss of power and risk of breaking which would otherwise be met. As the decrease of diameter progresses, the wire is found to exhibit a gradual increase in tenacity, which increase becomes very great when the wire is drawn very fine. Brass, and probably all other metals and alloys which have the requisite qualities to permit them to be worked by this process, are similarly increased in tenacity by the action of the draw plate. The precise combination of qualities 528 MATERIALS OF ENGINEERING XON-FERROUS METALS. which best fits metal for making fine wire, has never been exactly determined. It is not sufficient that the metal have simple tenacity, or tenacity and malleability, or even duc- tility, in the unlimited sense in which that term is often ap- plied. The observations and experiments of the writer have led him to suppose that perfect homogeneousness of compo sition, freedom from foreign substances, such as cinder in iron and oxide in copper and its alloys, and a high ratio of tenacity to resistance at the limit of elasticity are requisite. Some metals which have exhibited great strength and also very great ductility, when tried in the testing machine, have failed to work well when it has been attempted to draw them into fine wire. Those irons which have been drawn as fine as No. 36, or even to No. 40, have usually been marked by a limit of elasticity much lower than other very fine metals of equal tenacity and equal ductility as indicated by their be- havior in the testing machine. No. 40 wire has a diameter of 0.003 incn = 1 ~ 1 3> or 0.078 millimetre. (See Part II., Iron and Steel.) 296. Cold Rolling The Lauth Process. As has been above stated, it is occasionally necessary to anneal wire during the process of drawing, as it is rendered too hard to work without this treatment. This increase in the hardness of the metal is also accompanied by an increase, equally marked, in the elasticity of the wire ; and this change in the character of the material is quite independent of the simple strengthening which is seen in even the annealed wire. Any process of compression at low temperature, properly con- ducted, will exhibit the latter effect. Hammering metal at the ordinary temperature is sometimes resorted to to give it an increased hardness and elasticity. The same process is also practised to confer upon forgings a smooth and hard surface. If not intelligently executed, this process is liable to weaken the mass by extending the exterior portions, and thus straining the inner parts. Where practicable, it is prob- ably better to use the hydraulic press in doing this work. A process technically called " cold rolling " has been adopted to give increased stiffness and elasticity to iron, MECHANICAL TREATMENT OF THE METALS. 529 steel and other metals intended for certain special purposes, as for shafting, for the finger bars of reaping machines, and for other parts of machinery intended to have great stiffness and very perfect elasticity. FIG. 37. EFFECT OF COLD ROLLING. The precise temperature at which this effect can be pro- duced has not been determined. It is within a range which extends nearly, if not quite, up to a full red heat.* Prof. Johnson and Mr. Fairbairn found that the cohesion of wrought iron was practically unaffected at a temperature of * See Metallurgical Review, Oct. 17, pp. 159-162. 34 530 MATERIALS OF ENGINEERING NON-FERROUS METALS. six hundred degrees Fahrenheit, and this may be taken as evidence that the effect of cold rolling is attainable at tem- peratures exceeding the black heat. This process and its effects upon iron have been described in Part II. The accompanying strain-diagrams, Figure 37, ex- hibit this effect, and may be taken as illustrative of the effect of the process on all metals, and especially the bronzes to be referred to. 297. The Dean Process Cold Working Bronze has been practised in the United States by Mr. S. B. Dean, and in Europe, on a more extended scale, by General Uchatius, of Vienna. These experimenters endeavored to apply the process to the manufacture of bronze ordnance, and used the same general method of adapting it to the work. This method, as described by the inventor, Mr. Dean, in 1869, is the following: The gun is " placed in a frame, or upon a bed somewhat like a boring mill for guns, but instead of using a bar provided with cutters, there is fixed in the end of the bar a smooth cylindrical plug of hardened steel about 5-100 of an inch larger than the diameter of the reamed hole in the gun. The plug should be made of two frustra of cones with their bases connected by a short cylinder. " For condensing the bores of rifled guns, the plugs used should have ribs to correspond with the grooves previously made by the rifling machine. " The bore being well lubricated, the steel plug is made to traverse the bore by a screw or other suitable means till it reaches the bottom of the bore, proper provision being made to allow air and excess of the lubricant to escape through a vent in the plug or at the bottom of the bore. Instead of forcing a plug or plugs from the muzzle to the bottom of the bore, the condensation may be performed by commencing at the bottom of the bore and drawing the plug outward ; in which case the plugs should be so made as to be expansible. After the first plug has been removed from the bore, two or more similar plugs are successively forced through, enlarging the bore to the desired size. " Care should be taken that each succeeding plug shall MECHANICAL TREATMENT OF THE METALS. 531 have a diameter slightly larger than the one preceding it, and each plug should perform a slightly smaller amount of com- pression than the preceding plug, on account of the increas- ing hardness and density of the bore, which increases the resistance to be overcome by each successive plug." Dean found the effect of this treatment to be very marked in increasing the hardness, strength and density of bronze. A cylinder of metal taken from the sinking head of a bronze gun having originally a specific gravity of 8.321, a tenacity of 27,238 pounds per square inch (19 kilograms per square millimetre), and a hardness, by the scale used by General Rodman, of I, was given a tenacity of 41,471 pounds per square inch (29 kilograms per square millimetre). Its hardness was increased to 2.97. Its density, in a ring one- quarter inch thick, next the bore, was made 8.780. In the innermost thickness of one-eighth inch it was 8.875 ; an d the density of a circular piece one-quarter inch, taken across the bore, was 8.595. The increase here noted of 50 per cent, in tenacity by compression has been exceeded by other experi- menters. General Uchatius, the director of the arsenal at Vienna, has reduced this process to practice in the manufacture of guns for the Austrian army ; and, as he informed the Author by a note dated June, 1875, the official action of the Com- mittee on Artillery resulted in the promulgation of the order that " steel bronze " the name given by General Uchatius to the new product " is to be accepted as gun-metal in the Austrian army." The process of investigation and its re- sults are given to the Author by Uchatius substantially as follows : * 298. Uchatius' Methods of Treating Bronzes. Ordi- nary bronze for guns is an alloy, consisting of about 90 parts, by weight, of copper, and 10 parts of tin. Since the atomic * See the report by the Author to the President of the United States " On Machinery and Manufactures, with an Account of European Manufacturing Districts;" contained in the reports of Scientific Commissioners of the United States to the Vienna International Exhibition, 1873. Published under the direction of the Secretary of State at Washington, 1875. Also, see report of Colonel T. S. Laidley, in "Ordnance Notes," No. XL." $32 MATERIALS OF ENGINEERING NON-FERROUS METALS. weight of copper is 63.4, and that of tin 118, the above pro- portions of the alloy correspond to a combination of I equivalent of tin with 17 equivalents of copper. Experiment shows us that it is questionable whether these two metals form a chemical compound in these atomic proportions. When large molten masses of this alloy solidify, an alloy which is poorer in tin begins to crystallize first where it touches the mould, its composition being about 92 parts, by weight, of cop- per, and 8 parts of tin, or I equivalent of tin to 21 equivalents of copper ; while an alloy richer in tin is pressed from the former, and solidifies last. This latter alloy, then, forms in the inside of the casting, and also enters the cracks which sometimes form in the outer walls. This behavior in the fusion of alloys rich in tin was also noticed in the researches on alloys of copper and tin made by Alfred Riche.* M. Riche noticed that all alloys of copper and tin, except those whose compositions correspond to the formulas SnCu 3 and SnCu 5 , undergo refusion at the moment of solidification. An alloy richer in tin is separated, so that different compounds are to be found at different points in the casting. When the alloy consists of tin and copper in the proportion of I to 5, this refusion occurs to but a slight extent, but when the composition is different it becomes very serious. As a proof of the occurrence of these conditions in alloys, it may be stated that rich bronze of a very homogeneous character is always found in the smaller parts of bronze cast- ings ; for example, in the cascabel, or in the trunnions of a gun. This bronze contains about 8 per cent, of tin, while the body of the gun is permeated by thin sheets of tin. An 8-inch tube was made at the Royal Imperial Arsenal, for which 28,000 kilograms (61,600 pounds) of metal were employed. The greatest diameter of this casting was about 0.84 m. (33 in.), and the proportion of tin at this part was 8 per cent, on the outside and 12 per cent, on the inside. Bronze with 8 per cent, of tin has not yet been employed for guns, because its wear is greater than that of 10 per cent, bronze. " Gun-metal " has long been employed because of " Annales dc Chimie et de Physique" tome 30. MECHANICAL TREATMENT OF THE METALS. 533 its great tenacity and consequent safety, and because it has the advantage of cheapness and ease in working. Its strength has satisfied the demand nearly up to the present time, and it has, therefore, been retained in the manufacture of field- pieces, in spite of its tendency to " bulge " and to burn out. Modern practice, however, will no longer permit its applica- tion as formerly. From an accompanying table of properties of types of gun-bronze, we find those of ordinary gun-bronze, as com- pared with Krupp's steel for guns, to be BRONZE. STEEL. Tenacity. 2,260 kilograms per square 4 800 kilograms (68 160 Ibs ) Elastic resistance centimetre (32,092 pounds per square inch). 400 kilograms per square cen- Extension when broken. timetre (5,680 pounds per square inch). 15 per cent. Hardness ^depth of indenture) 12.5 millimetres (% inch). 10.5 millimetres (.42 inch). We see that the tenacity as well as the limit of elasticity of cast steel is almost twice as great as that of ordinary bronze, which has even less ductility than steel. If the prop- erties of bronze could not be further improved wrought iron being unreliable as gun-metal we would necessarily be compelled to accept steel. But, fortunately, new wants are generally supplied in time by the progress of science and art. A new modification of gun-bronze, which is much su- perior to ordinary gun-bronze, according to Uchatius' table of gun-metals, is now made, for which General Von Uchatius has proposed the name 4< steel-bronze," on account of the resemblance of its properties to those of cast-steel. If, instead of employing sand, we use iron chills of a cor- responding thickness of material, the process of solidification takes place with such rapidity that the alloy rich in tin cannot separate, and the bronze becomes perfectly homogeneous. The strength rose to 3,050 kilograms (43,210 pounds per square inch), the elastic limit remained at 400 kilograms, the hardness (depth of indenture) at 12.5 millimetres, .5 inch), while the amount of stretch before breaking, or the ductility 534 MATERIALS OF ENGINEERING NON-FERROUS METALS. of the material, rose to 40 per cent. These improvements in the quality of bronze are a step forward in bronze-casting, but it is, nevertheless, not sufficient to satisfy modern require- ments. A gun-barrel cast in this manner would not burst, as the ductility of the material (40 per cent.) is enormous ; but it would not be capable of resisting the pressure of the gas ; and, since the elasticity is not greater than with ordinary bronze, the gun-barrel would " bulge." The hardness also remained unchanged, and it is therefore not great enough to cut the grooves in the sabots of the shot. General Von Uchatius next tried to roll a piece of the chilled bronze cold. This could be done, although consider- able power was necessary. Not the slightest crack was pro- duced, even when stretched to the amount of 100 per cent, of its original length. When the bronze had stretched 20 per cent., it attained the strength, hardness, and elasticity of steel. The figures are as follows : The tenacity, 5,066 kilograms per square centimetre, (71,937 pounc^ per square inch). The elastic resistance, 1,700 kilograms per square centi- metre (24,140 pounds per square inch). The hardness (depth of indenture), 10.2 millimetres (.41 inch). It is evident that if this characteristic of chilled bronze, of assuming the properties of steel, when rolled, could be em- ployed on the inner surface of gun-barrels, the process would be of great value. On examining the table of gun-metals, he remarks the peculiarity that all tough metals assume a much higher elasticity when they are stretched beyond the elastic limit, which fact had already been noted by Dean. In this fact we may find the explanation of a well known phenomenon, often observed. A bronze barrel which was not strong enough to resist the charge, and which, therefore, " bulged," still approximately retained its form after long- continued use. It could even be reduced, by turning off the outside, without losing its resisting power. The natural chilled bronze has its limit of elasticity at 400 kilograms, (5,680 pounds per square inch), and permits a stretch of 0.0004 MECHANICAL TREATMENT OF THE METALS. 535 of its length ; while if a permant set of 0.00441 of its length is produced, its elastic limit becomes 1,600 kilograms (22,720 pounds per square inch), and its stretch within the elastic limit, 0.00192. The rolled chilled bronze attains its limit of elasticity at 1,700 kilograms (24,140 pounds per square inch), and has an elastic extension of 0.0017 of its length, while a permanent stretch of 0.00018 of its length raises the limit of elasticity to 2,400 kilograms (34,080 pounds per square inch) and its elastic extension to 0.00252. This advantage is as great with steel, wrought iron, and in general all extensible metals, but it has never been taken advantage of in the manufacture of guns, until Dean and Uchatius made the application. The following principle was enunciated by General Von Uchatius as a theory of working a gun-barrel from a homo- geneous, very ductile, and tough metal. It is based upon results obtained by precise measurements of the properties of the metals : /. The work performed by the pressure of the gases of the exploded powder, and destroying the fit of the shot by enlarging the bore, sliould be performed origin-ally by mechanical means, and to a far greater extent than will be produced by the heaviest charge. By this means the elastic limit of the metal of the barrel is increased to such an extent that the smaller press- ures of gas produced in discharging the gun have no effect. //. The surface of the bore must be submitted to a process resembling rolling to such an extent as to give it the necessary hardness. By this process of mechanical working of the casting the material is not overstrained. Its quality is not injured ; on the contrary, as this extension goes on in the cold state, the molecules take new and stable positions, refining the metal. Its properties are, therefore, improved. Before proceeding fo the method of working on the cast- ing, it was necessary to solve two very important problems, namely : Which alloy of copper and tin is best suited for chilled casting ? MATERIALS OF ENGINEERING-NON-FERROUS METALS. How can the quality of the metal at the inside, or nearest the bore, be made to correspond to that of the alloy at the outside, so that the metal can be subjected to the process of rolling ? In order to determine the best alloy, a small cast-iron chill was made, of 25 millimetres (i inch) and 50 millimetres (2 inches) width in the clear, and 25 millimetres (i inch) thick- ness of sides, into which the following alloys were cast : 12 per cent, bronze. 10 per cent, bronze. 8 per cent, bronze. 6 per cent, bronze. 10 per cent, bronze, with 2 per cent, addition of zinc. 10 per cent, bronze, with I per cent, addition of zinc. 8.5 per cent, bronze, with ^ per cent, addition of zinc. The last of these alloys is that which Lavissiere exhibited at the Vienna Universal Exposition of 1873, and which attracted attention by its uniform and homogeneous appear- ance and by its peculiarly excellent quality. Two rods were cut from each of the castings, and these were rolled out until they acquired the hardness of " mild " steel. It became evident, during this process, that the 12 per cent, bronze could not bear rolling, and the tests were limited to the remaining alloys. It was found necessary to continue the rolling of the rods in order to reach the hardness of steel ; with the 10 per cent, bronze, to an elongation of 20 per cent. 8 per cent, bronze, to an elongation of 30 per cent. 6 per cent, bronze, to an elongation of 50 per cent, with the 10 per cent, bronze and 2 per cent, zinc, to an elongation of 10 per cent. 10 per cent, bronze and i per cent, zinc, to an elongation of 15 per cent. 8.5 per cent, bronze and J^ per cent, zinc, to an elongation of 20 per cent. The results of tests made can be seen in the following table : MECHANICAL TREATMENT OF THE METALS. 537 ALLOYS. TENSILE STRENGTH. ELASTIC LIMIT. ELONGATION WITHIN THE ELASTIC LIMIT IN O.OOOOI. SET IN PER CENT. OF LENGTH. Pounds per square inch. Kilograms per square centi- metre. Poundsper square inch. Kilograms per square centi- metre. 10 per cent, bronze 7 ',937 73.840 77,532 42,884 59.214 53.900 5,066 5,200 5.460 3,020 4,170 3,800 18,460 8,520 14,200 21,300 1,700 1,400 'Soo 600 1,000 I ,5 00 174 I 4 128 89 120 157 1.5 2-5 3-5 0-5 o-7 1.7 8 per cent bronze 6 per cent bronze zc per cent, bronze and 2 percent, zinc ... 10 per cent, bronze and i per cent. zinc. . . 8.5 per cent, bronze and % per cent. zinc. These tests showed that, in general, the 10 per cent., as well as the 8 per cent, and 6 per cent, bronzes, may be em- ployed in the new method of making gun-barrels, while the addition of zinc is of no use whatever, but, on the contrary, decreases its value in no inconsiderable degree. The 8 per cent, bronze was judged to be the best for large castings, and this has, therefore, been taken as the proper alloy for " steel-bronze." A number of trials were made to determine what method of casting and cooling would make the inner layers of the casting homogeneous, and give the necessary toughness for standing the treatment to which they were to be subjected. Simultaneously with these trials, those castings whose quality was shown to be good, by the appearance of the fracture, were subjected to the mechanical treatment. A hydraulic press was employed for this purpose, of a capacity of IOO,OOO kilograms (220,000 pounds). The following is a short sketch of the main features of the method which was employed for making gun-barrels sub- sequently to September, 1873: The castings were 260 millimetres (10.4 inches) thick, 300 millimetres (12 inches) long, having a bore of 80 millimetres (3.2 inches) diameter. They were conical and turned down at one end to 180 millimetres (7.2 inches) diameter. They were then placed vertically under the die of a hydraulic press, which was then driven through them, in accordance with the Dean system, a system the earlier existence of which General T7NIVERSITT 538 MATERIALS OF ENGINEERING NON-FERROUS METALS. Uchatius seems ignorant. The surface of the die was of well- hardened steel, and was a slightly-tapering cone, thus increasing the diameter gradually. But, since the resistance increased with the enlargement of the barrel, the difference between the diameter of the plunger and that of the last formed barrel must decrease gradually. Six plungers were employed in succession, of which the first increased the bore by 2 millimetres (.08 inch) and the last by y 2 millimetre (.02 inch). The original diameter of the bore, 80 millimetres (3.2 inches), was thus increased to its normal size of 87 milli- metres (3.88 inches) ; that is the increase amounted to 7 millimetres (.28 inch), or 8.75 per cent., while the exterior diameter of the casting was increased by 2 per cent. The surface of the bore which was thus produced had a hardness, when measured by indentation, of 10.5 millimetres (.42 inch), or equal to that of gun-steel ; it was as smooth as a mirror, and only needed rifling. It was further remarked that the same result as to hardness was produced at the end which was weakened by turning down, which would seem to indi- cate that the outer layers of guns do not come into play at all when firing. 299. Experiments on Compressed Bronze. The mate- rial of the first two experimental barrels of steel-bronze had the following properties : PROPERTIES OF STEEL-BRONZE. TEST-BARREL NO. X, NEAR THE TEST-BARREL NO. 2, NEAR THE Bore. Exterior surface. Bore. Exterior surface. Tensile strength per i square centimetre, in kilo- grams 4^250 6o,35 T,IOO 15,620 0.306 0.56 10.6 .42 3,32 47,M4 500 7,100 50 0.060 0.50 12 .48 4, 2 5o 60,350 I, TOO 15,620 16 J 0.306 0.56 10.6 .42 3,320 47^44 700 9,940 1. 0.060 0.50 12 .48 Tensile strength per i square inch, in prunds Limit of elasticity per i square centimetre, in kilograms Limit of elasticity per i square inch, in pounds . . btretch, ultimate, in per cent, of length Stretch, elastic, in per cent, of length Section at the point of rupture, which was orig- inally taken i.oo Hardness, depth of indenture, in millimetres Hardness, depth of indenture, in inches MECHANICAL TREATMENT OF THE METALS. 539 Both barrels were subjected to tests by firing. These tests were made on the " Simminger Haide," from 40 to 50 shots being fired daily, two shots with the diminished charge of I kilogramme (2.2 pounds), and 238 shots with the normal charge of 1.5 kilogrammes (3.3 pounds). The projec- tiles were 2^ diameters in length, and the powder used for the charge was large-grained powder, the size of the grains being from 6 millimetres to 10 millimetres (0.24 inch to 0.4 inch), the density was 1.605. The barrel showed no signs of either a widening of the bore or any other flaw after these tests. The test-barrel No. 2 was tried on the " Steinfelder Haide" to determine the decrease in precision of firing consequent upon the firing a great number of shots with the charge of 1.5 kilogrammes (3.3 pounds), and with projectiles 2^2 diam- eters in length, weighing 6^ kilogrammes (14 pounds). The velocity attained with this charge was 1,480 feet. In all, 2,130 solid shot were fired and twenty shells were thrown. The examination of the barrel showed the chamber to be quite unaltered. The enlargement, which was perceptible about o. I millimetre (0.004 inch) was due to burning out and to mechanical wear. The lands and grooves of the bar- rel were worn considerably, after this great number of dis- charges, by mechanical wear and by burning out, but from the muzzle to the vicinity of the trunnions the lands were left quite sharp, and consequently were capable of seizing the projectile with perfect accuracy, giving the necessary stability in the barrel. After 2,100 discharges, a projectile was purposely made to burst in the gun, in order to determine the amount of damage thus produced and its effect upon the accuracy of fit of the shot. The following series of 25 shots did not show loss of accuracy, although the grooves and lands were badly damaged, for the latter were crushed and the metal squeezed into the grooves. This method of working castings applies advantageously to the production of steel gun-barrels. Steel, having an elas- tic limit of 2,000 kilogrammes per square centimetre (28,400 54 MATERIALS OF ENGINEERING NON-FERROUS METALS. pounds per square inch) and a ductility of 20 per cent., can- not be produced by any hardening process or method of manufacture, except by stretching in the cold state. 300. Uchatius' Deductions. The steel-bronze barrels will, according to General Uchatius, prove to be better than those of steel, for the following reasons : On account of the quadruple price of the steel, and be- cause old steel-bronze barrels can always be remelted. On account of the time required in manufacturing, which with steel is six or seven times as long as that needed with steel-bronze. In order to produce a cast-steel barrel fitted with rings, the inner tube is first cast. It is then heated and worked under the steam-hammer ; it is then bored, and finally the rings are shrunk upon it. For this purpose are needed, not only very costly plant, but also skilful, experienced, and very reliable workmen. The steel-bronze barrels are simply cast, then bored and pressed, and finally drawn ; all of which manipulations are very simple. On account of the greater rapidity of destruction of the steel by atmospheric influences. The destructive effect of oxidation rapidly penetrates to the interior with steel, while steel-bronze merely receives a superficial layer of verdigris, which does not penetrate. Because steel barrels are not as safe for the gun's crew as steel-bronze barrels, of which the exterior layers are so tough that they must be stretched 50 per cent, before fract- ure. The cost of a steel-bronze barrel thus made and of the size here described is given as $175, and that of a gun made of steel at $750. 301. Frigo-Tension. There is, finally, another process which is applicable, however, only'to ductile iron and steel, and to such other metals as exhibit an elevation of any nor- mal elastic limit by the intermittence of strain which maybe usefully applied at ordinary temperatures with the result of increasing the elastic resistance, and, usually, the ultimate strength of the material. This process has been long used by bell-hangers when wishing to give wire greater stiffness MECHANICAL TREATMENT OF THE METALS. 541 and uniformity of stretch ; but it has not become generally known or extensively applied in the arts. When a bar of copper, zinc, tin, lead, or other metal than iron or steel, is subjected to gradually increasing distortion, it offers gradually increasing resistance up to the point of rupt- ure, and this resistance follows a regular law in most cases, whether the distorting force is applied steadily or intermit- tently. This gradual increase of resistance is due to the fact that the normal elastic limit for all metals becomes higher as distortion progresses, until it finally coincides with the ulti- mate strength of the piece, and fracture then occurs. When, during the process of extension, the stress is inter- mitted, the effect of such intermission, as has been seen, Art. 285, is often to produce a marked change in the position of the normal elastic limit due to the degree of stretch attained, and it is found that on renewing the effort to distort the piece, the limit of elasticity, when distortion again begins, is not precisely where it was at the interruption of the process of distortion. In some cases the change is hardly, if at all, observable ; in other cases the elastic limit is found to have been elevated ; and in still other cases, where the load has not been removed, it is lowered. This difference has led to the division, by the Author, of the metals used in construction into two classes. One comprehends iron and steel, and, pos- sibly, other metals not yet determined. The other class com- prehends the inelastic metals, including copper, tin, zinc, and their alloys. 302. Comparison of Methods. The effects of the several methods of working which have been described can be well explained and illustrated by a comparison of the strain-dia- grams of the product of each. The effect of the processes which are adopted to improve metals by treatment before, or during, solidification after fusion, is to give greater strength, ductility, elasticity, and resilience. The strain-diagram is, therefore, given higher ordinates, a greater maximum abscissa and an enlarged area ; that is, the diagram of the untreated metal is given increased altitude, an increased extension, and a much greater area. 542 MATERIALS OF ENGINEERING NON-FERROUS METALS. The general character of the diagram remains unchanged, except as to dimensions, unless modified by peculiarities of subsequent treatment. The effect is the same in kind, to whichever class the metal may belong. It is the same with the Whitworth as with the Lavroff process. The treatment of the molten metal by fluxing before subjecting it to any mechanical manipulation, produces the same modification of the strain-diagram. A combination of the two processes, as the addition of phosphorus to bronze, with compression of the metal by the Lavroff method, would evidently give a still more important improvement and would be represented by a still more marked change in the strain-diagram. The process of working the metals at a red heat, as in the rolling mill and in the forge, effects changes which are in gen- eral exhibited on the strain-diagram by those modifications which indicate increased strength, ductility, resilience, and homogeneousness in the character of metals. The effect is not precisely the same on the two classes. All cast and un- worked metals give a strain-diagram of approximately para- bolic form and free from any sudden change of curvature. Their elastic limits are, therefore, modified by the slightest distortion, and an elastic limit is found at the zero of load and of strain. This was first explicitly stated by Hodgkin- son, when reporting on his experiments on cast-iron. The strain-diagrams published by the Author in the cases already referred to* show that this is true of the other cast metals. The slightest force in all such cases produces a set. After having been subjected to the action of the rolls or of the hammer at a red heat, the inelastic metals of Class 2 give the same smoothly curved diagram as before, the change being observable in the dimensions and not in the form of the curve. The metals in Class I, however, give strain-dia- grams which are of a somewhat different form. Instead of the form O E A, Fig. 38, a sharp change of direction is seen at some point, and the diagram is more like O E C. The normal elastic limit of the piece when tested is found to be at first rapidly elevated as distortion progresses, until at some * Part II., Fig. 98 MECHANICAL TREATMENT OF THE METALS. 543 point, E, a sharp change of the ratio of the distorting force to the amount of coincident distortion takes place, and the sets become approximately equal to the total distortions. This point is the " apparent " elastic limit, which is the elastic limit as commonly understood. Rolled or forged metals of the first class, therefore, have an apparent elastic limit which fs much more clearly marked than in any cast metal, or in any metals of the second class. FIG. 38. STRAIN-DIAGRAMS. Thus, in Figure 38, let the curves A, B, and C represent the strain-diagrams, (i) of any cast metals, (2) of a rolled metal of the second class, and (3) of a part of the diagram of rolled iron, respectively. The characteristic differences be- tween the two rolled metals and between them and the cast metal are well indicated. These curves are copied from actual diagrams produced automatically, and are real graphic repre- sentations of those characteristics. The depression seen at D is an indication of the presence of fibre in the metal. 303. The Effect of the Processes of Rolling and of Hammering the metal cold are graphically represented in Figure 39. The strain-diagram A is a copy of the beginning of that given in the Mechanical Laboratory of the Stevens Institute of Technology by a piece of merchant bar iron of excellent quality. That marked B is a copy of the initial 544 MATERIALS OF ENGINEERING NON-FERROUS METALS. portion of a diagram produced automatically by a sample of cold-rolled shafting made by treatment of a piece of iron of similarly good quality.* It is seen at a glance that the effect of cold-rolling is, in this case, to bring the apparent elastic limit nearly up to the maximum of resistance, which is only attained in the un- treated metal after very great distortion. As has already been stated, the piece also exhibits a much greater ultimate FIG. 39. STRAIN-DIAGRAMS OF IRON. resistance than the same metal prepared in the usual way. The resilience, taken at the elastic limit, is immensely in- creased, and the elasticity of the metal was found to be the same, wherever measured, while distortion, was progressing. The metal is probably compacted to some extent, but to so slight a degree that the resulting change of density has not been measured.f Examining the piece after fracture, it is found that concentric layers differ from each other in the degree in which they exhibit the effect of cold-rolling, but that in each layer the metal is rendered exceedingly homogeneous. As in all ordinary work the metal is never intended to be perma- *See plate, above referred to, Part II., strain-diagram No. 85; see also Report by the Author on an extensive series of tests of cold-rolled metal for the American Iron Works, 1877. f Major Wade found no increase of density, but apparently a slight decrease after cold-rolling iron. MECHANICAL TREATMENT OF THE METALS. 545 nently distorted is never expected to be subjected to strains which can produce permanent set the increased value for constructive purposes which is conferred by this treatment is measured by the increase noted in its strength, elasticity, ductility and resilience within the elastic limit. It is seen to be immensely great. The effect observed is, in this case, due probably to the elevation both of the apparent and the nor- mal elastic limit, by both the simple condensation and in- crease of horn ogeneojusn ess which occurs with metals of the FIG. 40. STRAIN-DIAGRAMS OF BRONZES. second class, and by that peculiar exaltation of tenacity, by some as yet not fully determined change in molecular rela- tions, which is only known to take place with metals of the first class. The effect of the cold-rolling process is, however, the same in kind, so far as it affects the form of the strain-dia- gram, where the second class of metals is treated, and the curves seen in Figure 40 are copies of diagrams produced automatically, during the tests of two pieces of bronze from an old gun. The diagram A was given by a test piece taken from the exterior of the gun, where it had been little, if at all, affected by the compression ; and that marked B was given by a specimen taken from the inside of the bore, where the effect of compression was most marked. On comparison, it is seen that the effect of the process of 35 546 MATERIALS OF ENGINEERING NON-FERROUS METALS. compression, at the ordinary temperature, of both classes of metal is the same in kind. So far as it affects simply the re- lation of the distorting force to the distortion produced by it in each, the result of the operation is the elevation of the limit of cohesion by condensation of the metal and by the production of greater homogeneity. In the case of iron and steel, the effect of this treatment is heightened by the pecu- liar property of those metals which has been already fully described. With both, the result of cold working is highly advantageous for many purposes. In some cases as, for ex- ample, when the metal is to be subjected to extremely violent shocks, and is therefore likely to be permanently deformed, and where it should be capable of offering a maximum resili- ence up to the point of actual rupture, e.g. t the armor-bolts of an iron-clad the metal should not be subjected to this process, or should be treated very cautiously. Where great strains are liable to be met, but without impact, as in the more usual applications of such metals in machinery, and as in ordnance, where the tremendous p&ssures exerted are due only to the elasticity of a confined gas, it is as evident that cold-worked metals are well fitted to give a maximum resist- ance without counterbalancing disadvantages. 304. Historical Discovery of Facts and Determination of Laws. It is impossible to say just when all the facts and laws above given were first known. The first intelligent statements of the simpler facts were made, probably, by Galileo, who, in 1656, published a work " Opere di Galileo" at Bologna. Robert Hooke, in 1676 and 1678, was the first to announce the important principle which forms the basis of our theory of elasticity of bodies within the elastic limit, in the now celebrated Latin phrase, ut tensio sic vts the extension is proportional to the force. Marriotte, Leib- nitz, Parent, Bernouilli, and other mathematicians, discussed the theories of flexure and of rupture of beams with equal mathematical skill and practical ignorance. Coulomb, about a century ago, gave the best mathematical treatment pub- lished up to that time, and made some experiments which were of real value. Dr. Thomas Young, the ablest writer MECHANICAL TREATMENT OF THE METALS. $4? u is ever devoted a mind rich alike in scientific knowledge h. power of useful application, to practically valuable study, defined the modulus, or coefficient, of elasticity, and reduced to practical shape the laws enunciated by Hooke and other earlier writers. Dr. Young also defined the quality which Professor Lewis Gordon afterward called, " resilience," and showed that it measured the amount of " work " done in distorting a body.* The first connected and special treatise on strength of materials, and on construction, was the work of the dis- tinguished Navier, the lecturer at the cole des Fonts et Chans- stes, in 1824 ; but Tredgold had already prepared his excellent treatise on iron. Since then, Fairbairn and Hodgkinson, Morin, and many others, have written valuable treatises on the subject, or upon special divisions. Probably the most reliable and extended of early re- searches in this field were the experimental investigations of Muschenbroek, of which an account is given in his Introduc- tion to Natural Philosophy, published in 1762. Banks, in 1803, an d Rondelet, in his "Art de Batir" 1814, published the results of experiments on iron. The best work which has since been done has been published within a few years by Fairbairn and Hodgkinson, Kirkaldy, Styffe, Bauschinger, Wohler, and by our own countrymen, Rodman, Wade, Shock and some other experimenters in special directions. The fact of the existence of an elastic limit was very early discovered. Duleau, in his u Essai Thtorique et Experimental sur la Resistance du Per Forgt" printed in 1820, gives the elastic limit of that metal as at 8,540 pounds per square inch, and at an extension of about 1-3333 f tne original length of the piece in tension. Tredgold, writing in 1823, says: U I find that while the elastic force, or power of restoration, remains perfect, the extension is always directly propor- tional to the extending force, and that the deflection does not increase after the load has been on for a second or two ; but when the strain exceeds the elastic force, the ex- tension or deflection becomes irregular and increases with * Thomson and Tait; Nat. Philos , vol. i., part ii., p. 228. 548 MATERIALS OF ENGINEERINGNON-FERROUS METALS. time." Coulomb had already, many years before, noticed that many materials take a permanent set long before the breaking point is reached, and Emerson had, as early as 1758, asserted that the materials of construction should not be sub- jected to a force exceeding from one-third to one-half their ultimate resistance, and thus proposed the now invariable practice among intelligent engineers of taking a certain " factor of safety." In Tredgold's time, also, the work of Telford, Brown, Rennie, Barlow, and Rondelet, was well known. The fact that the elastic limit of a piece of metal exceeds its primitive value more and more as the piece is more and more distorted, was exhibited by some of the very earliest of these experiments. Dr. Young, in 1807, made the fact the basis of his remark: "A permanent alteration of form limits the strength of materials with regard to practical purposes, almost as much as fracture ; since, in general, the force which is capable of producing this effect is sufficient, with a small addition, to increase it till fracture takes place." (Nat. Phil., vol. i., p. 141.) He also pointed out the impor- tance of the determination of the resilience of a piece as a measure of its power of resisting impact. Tredgold gives, 1823, simple rules for the application of this principle, and both indicate the necessity of noting the variation of the re- sistance as distortion progresses in order to obtain a measure of that resilience. 305. Experiments published in 1840, in the Phil. Trans- actions, by Hodgkinson, were the first to supply data for an exact determination of the method of variation, and of the values of the normal elastic limit from the instant of its de- parture from its primitive value. His work is still quoted as standard authority, and as the most extended as well as thoroughly precise series of experiments yet made. His later work, extending over several years, is no less valuable. His tabulated results of test showed that sets occur with very light, if not under all, loads ; that the sudden change which marks what is here termed the apparent elastic limit, is followed by a gradual elevation of the limit as distortion proceeds, and that the normal elastic limit has a value, for MECHANICAL TREATMENT OF THE METALS. $49 each stage of distortion, which may be expressed by formulas of the kind already given. The fact was shown that the in- crease of resistance, as change of form occurred, became less and less marked up to the maximum. Clark, in his account of the Britannia and Conway bridges, in 1850, makes the statement, based on results obtained by Hodgkinson and himself: " We have seen that as we increase the permanent set of wrought iron we diminish the subse- quent extension and compression from any load, and we have alluded to the fact that the tubes would have deflected less from any given load if the top and bottom had been previously compressed and extended by any artificial strain. It follows from this consideration that if the compressed and extended portion of a wrought iron bar could be, by any artificial means, permanently strained previously to its em- ployment as a beam, such a beam would deflect less than a new bar, and would be practically a stronger beam, since the strength is regulated solely by the bending of the bar." This is probably the first time that such a statement was made of this now well-known and very important principle. Long after, few engineers were aware of the fact that it was then so distinctly enunciated and that the discoverer determined, by direct experiment, the effect of this method of treatment. Clark gives the tabulated results of test of bars thus treated, beside those derived from the test of other bars left in their original state. The former deflected but 1.765 inches under a load of 46.5 hundredweight; while the latter de- flected 5.145 inches under a load of 41.9. The bars were \y 2 inches square and the supports were 3 feet apart. Werder, at Munich, in 1854, used tie-rods which, by a single effort of tension, had been similarly stiffened. Neither Clark nor Werder seems to have understood the peculiar phenomenon of the exaltation of the normal elastic limit by intermitted strain, or to have availed himself of it by re- peating the efforts of distortion. Later experiments made at the Woolwich dockyard ex- hibited another interesting and important phenomenon due to the same characteristic. A rod was broken several times 55O MATERIALS OF ENGINEERING NON-FERROUS METALS. in succession, and exhibited continually increasing ultimate resistance. Other rods similarly treated gave the same re- sult. The mean of 10 gave a tenacity at the first fracture of 24.04 tons per square inch ; the means of succeeding breaks were at 25.94, 27.06, 29.20, while the extension varied too irregularly to indicate any law. Similar experiments have since been made in 1873, by Bauschinger and other experi- menters. It was at first generally supposed that the last noted behavior of iron was due to the obvious fact that the bar must have broken at the weakest point first, at the next weakest place next, and so on, until the last fracture occurred at very nearly the section of maximum strength of the bar. It is now, however, evident that it is, or may be, due partly to the action noted by Clark, and also that it may take place in metals of both the classes which have been above defined by the writer. In the iron class, however, the effect is un- doubtedly more marked than in metals of the tin class, since there the exaltation of the normal elastic limit also comes in to increase the resisting power. 306. The Exaltation of the Normal Series of Elastic Limits by intermittence of strain and by lapse of time at a constant distortion, was observed by the Author in 1873. Commander L. A. Beardslee, U. S. N., independently noted the same phenomenon, later in the same year. The latter has since determined the magnitude of this change in iron during periods varying from one second to one year. (See Part II., Art. 298.) The Author, at about the same time, ob- served the depression of the normal series of elastic limits in the inelastic metals. As early as 1858, Prof. James Thomson, who had seen the importance of the property which produced the variation of resistance of materials between their primitive elastic limits and their ultimate fracture, and had called it "viscosity," had shown its effect in modifying the mathematical expressions deduced for the torsional resisting power of metals. He pointed out the marked difference in the forms of these formulas where applicable to brittle and to ductile, or viscous metals, and, in the latter case, to the resistance within and MECHANICAL TREATMENT OF THE METALS. 551 beyond the primitive elastic limit. Almost nothing has, however, been since done in the further modification of work- ing formulas with reference to the position and variation of the normal elastic limit, or to the determination of actual resistance, except that the Author has applied the same proc- ess to the modification of formulas for transverse resistance of tough metals, and independently of Prof. Thomson, but many years later, to the general case of torsion and to the inter- mediate condition in which a part only of the section is strained beyond the primitive elastic limit. M. Tresca and Captain Beardslee have shown, as has the Author (1873-83), all working independently, that, with iron, the variation of the normal elastic limits may extend nearly or quite up to the point of actual rupture, and that the mod- ulus of elasticity remains almost unchanged. The Author, experimenting with all the common materials of construction and with the whole range of alloys of copper-tin and copper- zinc and with the copper-tin-zinc alloys, has found the same to be true. Fairbairn, who was thoroughly familiar with the behavior of iron under strain, supposed the increase of resistance with distortion to be a consequence of the gradual bringing into action of particles in bodies which are not homogeneous as to strain, as the fibres of a rope are brought gradually into tension as the rope is more and more stretched. The Author has proposed a very similar explanation of the exaltation of the normal elastic limit by intermitted strain, and has shown how such a condition may be produced by the process of manufacture of those metals which exhibit that phenomenon most strikingly, but does not regard it as a satisfactory ex- planation of the kind of variation of the elastic limit which is observed in both classes of metals alike, to explain which it was offered by Fairbairn. Kick has (1870-80) shown the increased resistance of soft bodies attacked by shock, and confirms the deductions of the Author in that respect. 307. Strain-Diagrams. Gen. Morin was probably the first, about 1850, to represent the relation of the distorting 552 MATERIALS OF ENGINEERING NON-FERROUS METALS. force to the amount of distortion by the graphical method, and, in his "Resistance des'Materiaux" plotted beautifully the results of Hodgkinson's experiments. His curves exhibit perfectly the characteristics of the metals, the tests of which they represent, and exhibit plainly and accurately the variation of the elastic limit by continued strain. They do not, of course, indicate the exaltation of the normal limit by intermitted strain. Mallet, in 1856, uses the same curves to illustrate his application of the principle of the equivalence of the work done in producing fracture of the materials used in the construction of ordnance with the resilience of the metal, and the vis viva of the shot or other mass attacking by impact. Gen. Rodman, Major Wade, Kirkaldy, Styffe, and other later experimenters, have used the graphical method during the last quarter of a century in illustrating nearly all their work. In all such strain-diagrams, the variation of the elastic limit is exhibited, and the law of its variation with gradual change of form is expressed. Rodman was the first investigator to adopt the method as a system, using it in his report on his experiments on metals for cannon made in 1856 and 1857. Finally, the Author, in 1873, observed the exaltation of the normal series of elastic limits as recorded on automatic- ally produced strain-diagrams, and gave an account of that, and of other interesting phenomena exhibited by the auto- graphic strain-diagram, 308. History of Processes of Working Metals.- Re- verting to the several processes of working metals which have been described, it will be seen that the methods of securing improvement by an increase of homogeneousness by treat- ment of the metal ^hile fused, have no relation to any other modification of the elastic limit than that which distinguishes a structurally weak and defective material from a more per- fect specimen of the same metal. The processes of cold-roll- ing and of other methods of compression of cold metal in- volve, whether the metal be iron, steel, bronze or brass, that form of variation of the elastic limit which has been known since the time of Tredgold, and possibly of Muschenbroek, MECHANICAL TREATMENT OF THE METALS. $53 in addition to the change produced by the condensation of solidifying metal, and in a marked degree. The ordinary processes of working metal hot are intermediate in character between the other two. It is seen that the iron class, whether worked hot or cold, experiences, besides, a change which the writer has proposed to denominate the " exaltation of the normal elastic limit by intermitted strain." It is seen that the latter action is not involved in the cold-working of bronze. lntemay Cooled Inrot FIG. 41. INGOTS. In securing homogeneousness of structure by treatment of the molten metal, various methods of fluxing have been prac- tised from an unknown and very early period. The most suc- cessful methods have involved the use of phosphorus as a flux in casting bronze and of the silicide of iron and man- ganese for iron and steel. The method of compression of molten metal at the point of solidification was first brought into use by Sir Joseph Whitworth, of Manchester, England, about 1860. It was subsequently adopted on the Continent of Europe, and is now becoming well recognized as one of the most efficient known methods of producing metal of the highest possible grade. This method was first applied to the 5 54 -MA TERIALS OF ENGINEERING NON-FERROUS METALS. production of bronze guns by Colonel Lavroff, in the Russian arsenals, about 1867. By him the process was perfected in 1870. Chill-cast bronze was probably first proposed by Mallet in 1856, and he at the same time proposed the use of a hollow core to be cooled by currents of air, as in Figure 41. This method was adopted with great success by makers of bronze a few years later. It was adopted by General Uchatius in 1 873, after having seen the remarkable success of M. Lavissiere, who exhibited a bronze gun made in this way at the Vienna Exhibition of that year. Colonel Rosset, of the Italian artil- lery, had also adopted the same method, and it is referred to in his work, " Esperienze Meccaniche sulla Resist enza del Prin- cipali Met alii da Bocche da Fuoco. Torino, 1874," in which he also recommends the adoption of the Dean method of making bronze guns. The form of chill used for ordnance is shown on a subse- quent page. The ordinary methods of forging and working metals at a red heat were introduced hundreds of years ago, and their early history is quite unknown. Rolling mills for working iron were introduced about 1784 by Cort, the inventor of the process of puddling. Wire was made by hammering by the ancients and at a date which is not known. Wire drawing was invented 500 years ago, in Nuremberg, Bavaria, by a " wire-smith " named Ludolf. By the middle of the seventeenth century the busi- ness of wire drawing had been imported into Great Britain, and was employing thousands of people in England and in Germany. In 1813 Dr. Wollaston introduced his method of enclosing one metal within a bar of another metal and drawing down the two together. When finished the outer coating was dissolved off by an acid, and the inner and ex- tremely fine wire was left perfect. Platinum wire has been thus made, by enclosing it in silver, of but i-3O,oooth inch diameter. Mr. Brockedon, as early as 1819, using the pre- cious stones as draw-plates, produced wire 0.0033 mcn m diameter. MECHANICAL TREATMENT OF THE METALS. 555 309. Cold-working Iron, as a system, has been prac- tised but a comparatively short time. It had long been known that such treatment imparted stiffness and elasticity to metals, but it was not known at what stage of the process of condensation, if any, the action ceased to produce benefit and became liable to injure the metal by weakening it by the introduction of internal strains. It was well known to ex- perienced engineers and metal workers that cold-hammered iron, and iron rolled cold, was often seriously injured by being worked too cold ; and the Author was accustomed, many years ago, to give special instructions to the smith who was about to make the forgings of a steam engine which were to be left without tool finish, not to attempt to give them the fine finish under the hammer which may be given by hammer- ing at a " black heat," lest they should be weakened by the treatment. It was not then generally known that cold-work- ing might be so conducted, and safely, as to secure an in- crease of strength. The process of cold-rolling was introduced in the United States by its inventor, Bernard Lauth. His experiments were first made in 1854, and in 1857 he fitted up a set of rolls for systematic experiment ; and in January, 1858, he brought out cold-rolled iron as an article of manufacture. Two other in- ventors, Messrs. Cuddy and Savory, invented very similar processes almost simultaneously with their successful rival Lauth. Mr. Lauth was assisted pecuniarily, and by the prac- tical knowledge of, Mr. B. F. Jones, and the work was done at the mills of the American Iron Works, Pittsburgh. The proc- ess was introduced into Great Britain by Lauth in 1858. He introduced it into France and Belgium in the following year. The process has now become one of the well-established methods of iron-working, and is gradually becoming recog- nized as a valuable method of modifying the properties of steel, bronze, and other metals. As applied to iron and steel, it evidently results in the strengthening of the metal by condensation and by the pro- duction of greater homogeneousness of structure, and also gives stiffness and elasticity by the long-known form of ele- 556 MATERIALS OF ENGINEERING NON-FERROUS METALS. vation of the primitive elastic limit, as well as by the exalta- tion of the normal limit by the action ascribed by the Author to intermitted strain. As applied to gun-bronze and other metals of the tin class, it produces its useful effect only by the first two methods of change. 310. Cold-working Bronze and that class of metals by Mr. Samuel Buel Dean, of Boston, Mass., was applied by him to the improvement of gun-bronze at some time previous to 1859, at which date he laid his plan before the ordnance officers of the United States War Department, and illustrated its effects by treating samples of gun metal, as has already been described. The Ordnance Bureau ordered guns to be made by the Dean method in July, 1870, and the work was subsequently interrupted in consequence of the neglect of Congress to vote the necessary funds. In Great Britain, the Committee on Field Artillery for India, in 1870, reported in favor of the adoption of this method. General Uchatius, of the Austrian artillery, adopted the process in 1873, using the method of condensation described in the patent of the inventor, Dean, which had been filed in Vienna July 1 6, 1869, in Register sub-vol. xix., fol. 378. The British and French patents were dated May 10 and May 12, respectively, of the same year. The United States patent was dated May 18. FIG. 42. CHILL Uchatius adopted the method of chill-cast- FOR ORDNANCE. ing SU g ge sted by Mallet in his work " On the Construction of Artillery," as has already been stated. The first information given abroad relating to the Dean process was probably the statement made by Mr. Clemens Herschel to Mr. Isidor Kanitz, of Vienna, May 18, 1869. The following figure represents Dean's apparatus. The metal cylinder to be strengthened, A, is supported by a cast- ing, B, while the rod, C, carrying the mandrel, is driven through it. The adoption of the process invented by Dean, by the MECHANICAL TREATMENT OF THE METALS. 557 Italian military authorities, was advised by Colonel Rosset also, and is referred to in his work on gun metals, published almost simultaneously with the description, by General Uchatius, of the details of the method of application of the Dean process in the Austrian arsenal. 311. Conclusions. The processes which have been described at such length in the pre- ceding pages are regarded as the most important known processes of modification of the primary \-^' t ^i c 1 FlG. 43. COLD- qualities of the useful metals. WORKING It may be concluded, from what has pre- BRONZE. ceded, that the proper method of preparation of metal to secure a maximum value is the following: (i.) Reduce the metal, when possible, to the molten con- dition, flux thoroughly with such a flux as will remove, first, all deleterious substances with which the metal may be con- taminated ; secondly, every particle of gaseous oxygen and of oxide ; and, thirdly, all other occluded gas liable to pro- duce "blow-holes." (2.) Cast the metal under heavy pressure, in order to secure maximum density and to close up every pore as per- fectly as possible. If the metal is an alloy which is liable to liquation, it should be cast in a chill of sound iron and of considerable thickness. (3.) If the metal is either iron or steel, produce any con- siderable change of shape which may be desired by rolling, by the drop-press, or by hydraulic forging at a full red heat, and permit it to remain unused as long as is possible, in order that the internal strain, unavoidable to some extent with any method of treatment, may be given time to become reduced by that process of flow which will ultimately relieve it. If stiffness and a more perfect elasticity are demanded, finish by the process of cold-working, taking great care not to carry it so far as to seriously injure the continuity of the metal. (4.) The bronzes, and other metals of the inelastic and viscous class, may be given very considerable modification of form by the processes of working cold. The same precau- 55$ MATERIALS OF ENGINEERING NON-FERROUS METALS tion must be taken to avoid destruction of continuity, and thus, by the production of incipient fracture, permanently and seriously injuring it. By observing these precautions, the maximum value of the metal for constructive purposes may be attained. Whitworth has made " homogeneous iron " castings having a tenacity of 35 tons per square inch by his process, and the Author has made brass without any special treatment, either by fluxing, compression, or other modifying processes, having a strength of 70,000 pounds per square inch (4,921 kgs. per sq. cm.) It is not unlikely that the theoretical maximum for any material the maximum due to the effort of the force of cohesion, and that which is perhaps approached, in special cases, in fine wire may be nearly attained, even in large masses, by the skilful and intelligent combination of the processes which have been here described in the treatment of such cast metals, and in their adaptation to purposes of construction. INDEX. ART. PACK Alloys 28 39 aluminium 99, 100 178, 180 [See Antimony.] Babbitt's anti-friction ' 139 215 [See Bismuth, Brass.] Britannia metal 126 202 cadmium and copper 107 186 characteristics 60 102 chemical natures 61 104 classified lists 142, 143 226 composition, special standard 141 218-222 conductivity, electric 68 120 thermal 67 118 [See Copper.] crystallization 69 123 effect of small doses of metal 135 212 electric conductivities 68 120 expansions by heat 60 , 116 ferrous copper 196 319 fusible 117 193 fusibility 63 1 10 German silver 102,138 182,215 gravities, specific 62 108 grey ternary 265 450 heat conductivities 67 1 18 expansions 66 116 specific 65 1 16 investigations, early 266 451 indium and platinum 128 203 iron, copper and tin 96 174 zinc 95 174 and tin... 113 189 iron and manganese 127 203 [See Kalchoids, Chap. VI., Lead.] liquation 64 113 lists, classified 143 226 manganese bronze 97, 98, 194. 195 175. i?6, 3^, 3*7 andiron 127 203 maximum 258-263 440-447 mechanical properties 71 126 nickel and copper 101 181 and zinc IO2 182 oxidation 70 124 pewter 120 202 platinum and indium 128 203 5 6o INDEX. ART. PAGE Alloys, preparation 134 210 phosphor bronze 192, 193 312-314 properties [See Chap. III.]. recipes, special 142 221 [See Resistances.] Spence's metal 129 204 specific gravities 62 108 heats 65 116 silicon and copper 109, no 187, 188 solders 140 276 special recipes 142 222 standard compositions 141 218 sterro-metals 220 368 [See Strength, Tin.] thermal conductivity 67 1 18 uses 93 172 [See Zinc.] Thurston's maximum j 258-262 440-447 Aluminium 51, 185 88, 565 bronze 99 176 uses loo 180 Analyses 27 39 and mixtures of copper-zinc alloys 227 376 Ancient knowledge of metals I 3 Anderson's experiments with gun-bronze 188 308 Annealing 293 526 and tempering, effect on density 276 484 tenacity 277 487 Anti-friction metal, Babbitt's 139 215 Antimony 47 82 bismuth and lead 122 202 tin 112 188 and zinc 125 202 and copper 104 185 and lead 1 18 196 and tin 123 202 tin and zinc 124 202 Appearance of brass, test-pieces 224 371 fractures 225 373 bronze test-pieces, external 201 325 fractures 203 330 Arsenic in alloys 55 95 Art castings in bronze 136 212 Babbitt's anti-friction metal 139 215 Bar copper 36 59 Behavior of bronzes under test 202 326 [See Mechanical Treatment, Resistances.] Bell-metal 189 308 Bischoff's tests. . 185 303 Bismuth alloys 116 190 antimony, tin, and lead 125 202 bronze 106 187 and copper 105 186 fusible alloys 117 193 lead and tin 117 193 ores 48 83 Brass [See Chap. V., X.]. INDEX. ART. PAGE Brass, alloys tested 223 370 analysis of mixtures 227 376 appearances of fractures 225 373 appearances of test pieces 224 371 application in arts 87, 90 159, 167 [See Bronzes.] casting, temperatures 226 375 classification, Mallett's 86 159 comparison of ductilities , 244 412 elastic limits 241 409 moduli 242 411 resiliences 240 409 resistances 239 406 specific gravities 243 412 compressive resistance 232 385 conclusions 245 413 from tests 239, 245 379, 413 compositions 85, 227 158, 376 definitions 84, 210 158, 366 ductilities [See Resistances, below] 244 412 elastic limits 241 409 moduli 221 368 experiments, early 219 367 fractures, appearances 225 373 foundry I Jl 207 [See Kalchoids, Chap. VI.] Mallett's classification 86 159 mixtures and analyses 85, 227 158, 376 moduli compared 242 41 1 of elasticity 221 368 Muntz metal 88 160 notes on tests 230 383 properties 92 165 special 89 161 records of tests 236 393 resiliences compared 240 409 resistances compared . 239 406 compressive 232 385 results of tests 228 378 shafts 235 392 tensile 231, 237 384, 404 torsional 234 391 transverse 233, 238 387, 406 results of tests 228 378 shaft resistance 235 392 special properties 89 161 specific gravities compared 243 412 Britannia metal 126 202 Bronze [See Chaps. IV., VI., IX.]. abrasive resistance of phosphor-bronze 193 314 alloys 72, 74, *97 13, 134, 320 tested 199 322 aluminium 99 178 uses ioo 180 Anderson's experiments on gun-bronze 188 308 appearance, external, of test pieces 201 325 fractures 203 330 behavior under test 202 326 36 52 INDEX. ART. PAGE Bronze, bell-metal, Mallett's experiments 189 308 bismuth 106 187 f See Brass.] casting, temperature 200 324 comparison of conductivities 216 363 ductilities 225 361 elastic limits 213 358 hardness , . . 217 363 moduli of elasticity 214 361 resistances 210 350 resiliences 211 355 specific gravities 212 355 compression [See Condensation, below] 208 340 resistance of ordnance-bronze 190 309 conductivities, comparative 216 "63 condensation [See Compression, above\. Dean process. ...*.... 297 530 Uchatius' method 298 531 experiments 299 538 deductions 300 540 [See Copper.] Dean's process of condensation 297 530 denned 72, 186 30, 306 density 79 141 ductilities, comparative 215 361 early compositions 77 139 elastic limits, comparative 213 358 elasticity moduli, compared 214 361 ferrous copper, strength 196 319 fractures, appearances 203 330 gravity, specific 212 355 gun [See Ordnance]. hardness, comparative 217 363 Riche's experiments 191 312 heat, modifying tenacity 270 477 history 73 131 impact resistance of manganese-bronze 195 317 [See Kalchoids, Chap. VI.] manganese-bronze 97 175 impact resistance 195 317 preparation 98 1 76 strength 194 316 maximum, Thurston's 258 440 metals used in research 198 322 moduli of elasticities, compared 214 361 oriental 78 140 ordnance 80, 187 141, 306 Anderson's experiments 188 308 [See Compression and Condensation, above.] Wade's experiments 190 309 phosphor-bronze 81 143 abrasive resistance 193 314 tenacity 192 312 uses 82 145 preparation of manganese-bronze 98 176 properties 75 136 principal 76 137 records of tests 204 335 INDEX. 563 ART. PAGE Bronze, results final 205 341 resistances, abrasive, phosphor-bronze 193 314 behavior under test 202 326 compared 210, 218 346, 350 l * c -, condensed gun-bronze 190 309 Uchatius' experiments 299 538 deductions. 300 540 conductivities 216 363 ductile 225 361 elastic limits 213 358 moduli 214 361 ferrous copper 196 319 hardness 217 363 Riche's experiments 191 311 manganese-bronze 194 317 impact 195 317 phosphor-bronze, abrasive 193 314 tenacities 192 312 tensile strain-diagrams 206 374 transverse strain-diagrams 209 348 silicon-bronze no 188 specific gravities 212 355 strength [See Resistance]. stress prolonged, effect 281 497 table 83 149 temperature of castings 200 324 tenacity modified by heat 270 477 tension, strain diagrams 206 344 test records 204 335 test pieces, appearance 201 325 behavior under test 202 326 Thurston's " maximum " 258-262 440447 [See Tin.] transverse strain-diagrams 209 348 Uchatius' experiments in compressed bronze 299 538 deductions. 300 540 methods.. . 278 531 uses of aluminium-bronze 100 180 phosphor-bronze 182 145 Wade's experiments on gun-bronzes 197 320 Bronzing 144 237 Calcination and roasting 3 9 Casting in bronze . 136 212 chill, effect 275 483 temperatures 200, 278 324, 488 Characteristics of metals 22 30 [See Properties, Resistances.] Chill-casting 275 483 Chemical analyses 227 376 character of metals 27 39 nature of alloys 61 104 processes in metallurgy, schedule 2 5 Classification of brasses, Mallett's 86 159 useful alloys 143 226 Cold-rolling, Lauth's process 296 529 tension, " Frigo "-tension 301 540 564 INDEX. ART. PAGE Cold-working metals 294 527 bronze 310 556 Dean's process 297 530 Uchatius' experiments 298 531 deductions 300 540 iron 309 555 Lavroff s process 290 523 Commercial copper 35 55 lead 46 81 metals, prices 59 99 rare 58 98 tin 39 66 Comparison of conductivity 216 363 ductility 215 361 elastic limits 213 358 hardness 217 363 methods 302 540 moduli of elasticity 214 361 resiliences 211 353 resistances 210 350 specific gravities 212 355 Complex copper alloys 115 189 Compression, brass 232 385 bronze '. 190 309 strain-diagrams 208 346 copper 171 278 Dean's process 297 530 hardness 16, 217 20, 363 Lavroff's process 290 523 [See Ductility.] malleability 20 27 non-ferrous alloys 157 255 [See Tenacity.] Uchatius' methods, experiments, deductions. 298-300 531-540 Conclusions, brasses and other copper-zinc alloys 229, 245 378, 417 kalchoids and copper-tin-zinc alloys 261 446 mechanical treatment 311 557 Condensation [& 363 heat, conductivity [See above.] latent ! 26 36 modifications of elasticity 272 480 stress 273 481 temperature of casting 278 488 tenacity , 269-271 476-480 mechanical treatment [See Table of Contents, Chap. XIV.]. cold-rolling, Lauth's pro- cess 296 529 cold- working 294 527 bronze 310 550 iron 309 555 Dean's process, condensa- tion 297 530 forging, drop, hydraulic 291, 292 524, 525 57 2 NDEX. ART. PAGE Resistance, mechanical treatment, frigo-tension 301 540 hammering 303 543 Lauth's process, conden- sation . 290 523 rolling 291, 303 524, 543 Uchatius' process, con- densation 298-300 531-540 wire-drawing 295 527 resilience 154 252 brass and other copper-zinc alloys 240 409 bronze and other copper-tin alloys. ... 2il 353 [See Strain-diagrams, belowJ\ rupture, modulus 163 262 theory 161 259 safety-factors 148 244 shafts [See Torsional, below] 166, 235 268, 392 shearing, of copper 170 277 shock, non-ferrous metals 153 251 proportioning for 155 255 strain-diagrams, brass and other copper-zinc al- loys, tension, transverse 237, 238 404 406 strain-diagrams, bronze and other copper-tin alloys, tension, compression, and transverse. 206, 208, 209 346, 347, 348 strain-diagrams, kalchoids and other copper-tin- zinc alloys 254 429 stress, intermitted effect on elastic limit 285 508 produced by change of temperature 273 481 repeated, effect on strength 287 515 steady and uninterrupted 284 500 uriintermitted, effect on deflection 283 502 elastic limit 285 508 variable effect on elastic limit 286 512 tempering, effect on density and tenacity. . . 276, 277 484-487 tensile [See Tenacity], time [See Stress, above], time of loading, effect 279 489 torsional, of brass and other copper-zinc alloys. . 234 391 kalchoids and other copper-tin-zinc alloys 246 414 non-ferrous metals, alloys 165 267 shafts 166, 235 268, 392 tin 180 294 zinc 182 298 transverse, brass and other copper-zinc alloys . . . 233 387 bronze and other copper-tin alloys. 197-205 320-341 copper 173 284 formulas 162 260 kalchoids and other copper-tin-zinc alloys 246 414 non-ferrous metals 159 256 strain diagrams, brass and other cop- per-zinc alloys 238 406 strain-diagrams, bronze and other copper-tin alloys 209 348 time, effects 279 489 tin 178 292 INDEX. 573 ART. PAGB Resistance, transverse, zinc 182 298 wire-drawing 295 527 Rolling 291, 303 524, 543 Riche, hardness of bronze 191 311 Roasting 3 9 Rupture [See Resistance]. modulus 163 262 theory 161 259 Safety factors 148 244 Shafts, strength of 166, ^35 268, 392 Shearing, resistance of copper 170 277 Shock, non-ferrous metals 153 251 proportioning for 155 255 [See Resilience.] Silicon and copper 109 187 Silicon bronze no 188 Smelting [See Metallurgy]. Solders 140 216 Specific gravities of alloys 62 108 brasses and other copper-zinc alloys. . . . 243 412 bronzes and other copper-tin alloys 212 355 densities and weights 19 25 Spence's metal 129 204 Standard alloys 141 218 Stereotyping 137 214 Sterro-metal 220, 247 368, 415 Strain-diagrams. 150 247 of brass, tensile 237 404 transverse 238 406 bronze, compressive 208 346 tensile 206 344 transverse 209 348 kalchoids and other copper-tin-zinc alloys. 254 429 Strength [See Resistance]. Stress, intermitted, effect on elastic limit 285 508 produced by change of temperature 273 481 prolonged, effect 280, 281 492-497 repeated, effect on strength 287 515 [See Resistance.] steady and unintermitted 283 500 unintermitted, effect on deflection 284 502 elastic limit 285 508 variable, effect on elastic limit 286 512 Structure and composition of metals 158 256 Taste and odor 21 28 Temperature [See Heat]. Tempering [See Annealing] 293 526 effect on density 276 484 tenacity 277 487 Tenacity, annealing effects 277, 293 487, 523 bell-metal '189 308 brass 231 384 strain-diagrams 237 404 bronze 207 344 condensation 297-300 53O-54O modification by heat 270 477 ordnance, Anderson's experiments 188 308 574 INDEX. ART. PAGB Tenacity, bronze ordnance, Wade's experiments 187 306 strain-diagrams 206 344 cold-rolling, effects 296 592 working, effects 294 527 upon bronze 310 556 iron 309 555 copper 167 270 modifications by heat 269 476 [See Compression, Ductility.] forging . . , 291, 292 524, 525 frigo-tension 301 540 hammering 303 543 heat modifications, bronze. 270 477 copper 269 470 non-ferrous 268 476 various methods 271 480 kalchoids and other copper-tin-zinc alloys 255 430 non-ferrous metals, modifications by heat 268 476 Ehosphor-bronze 192 312 See Resistance.] rolling 303 543 cold [See Cold-rolling, above]. strain-diagrams, brasses 237 404 bronzes 206 344 tempering, effects 277 487 thermo-tension 293 526 various metals, modifications by heat 271 480 wire-drawing 295 527 Ternary alloys, grey , 265 450 Tests [See Investigation]. Thermal conductivity 67 118 Thermo-tension 293 526 Thurston [See Alloys, Thurston]. Time [See Stress]. Time of loading, effect 279 489 Tin and antimony 119 198 bismuth and copper 112 188 lead 125 202 and lead 123 202 zinc 124 202 and bismuth and lead 117 193 commercial 39 66 and copper [See Bronze]. and iron 96 174 zinc 94, 248, 262 172, 416, 447 distribution 37 64 elasticity, moduli 179 294 fusible alloys 117 193 and lead in, 188 120,198 resistance 177 288 torsional 180 294 transverse 178 292 sources 37 64 stress prolonged, effect 280 492 ternary alloys, grey 265 450 and zinc . . 121, 263, 264 2OI, 449, 450 and iron 113 189 Torsional resistance of brass and other copper-zinc alloys . . . 234 391 INDEX. 575 ART. PAGE Torsional resistance of bronzes and other copper-tin alloys. . 205 341 kalchoids and other copper-tin-zinc alloys 251-259 419-442 non-ferrous metals 165 267 shafts 166, 235 268, 392 tin 180 294 zinc 182 298 Transverse loading, formulas 162 260 time effects 279 489 resistance, brass and other copper-zinc alloys. . . . 233 387 bronze and other copper-tin alloys. . . . 186 306 copper 173 284 kalchoids and other copper-tin-zinc alloys 246 414 tin 178 292 zinc 182 298 strain-diagrams, brass and other copper -zinc alloys 238 406 bronze and other copper-tin alloys 209 348 stress, non-ferrous metals 159 256 Uchatius' deductions 300 540 experiments on compressed bronze 299 533 method of condensation of metals 298 531 Wade's experiments on gun-bronze 187 306 Weights and densities 19 25 Wertheim on elasticity 184 300 Whitworth's process of compressing steel 289 519 Wire-drawing 295 527 Zinc and antimony 124 202 copper [See Brass]. and iron 95 174 and tin 113 174 and tin 248 416 history 40 40 iron and tin 96, 113 174, 189 metallic 42 73 nickel 102 182 ores 41 41 smelting 41 41 sources 41 41 strength 181 296 stress prolonged, effect 280 492 ternary alloys, grey 265 450 tests 182 297 tin 151, 264 201, 449 density and strength 265 450 :VERSITT) OF s UNIVERSITY OF CALIFOENIA LIBEAEY, BEEKELEY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW Books not returned on time are subject to a fine of 50c per volume after the third day overdue, increasing to $1.00 per volume after the sixth day. 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