RESEARCH LIBRARY THE GETTY RESEARCH INSTITUTE JOHN MOORE ANDREAS COLOR CHEMISTRY LIBRARY FOUNDATION © Raymond Pettibon WORKS OF DR. THURSTON. Materials of Engineering. A work designed for Engineers, Students, and Artisans in Wood, Metal, and Stone. Also as a Text-Book in scientific schools, showing the properties of the subjects treated. Well illustrated. In three parts. Part I. The Non-Metallic Materials of Engineering and Metallurgy. With Measures in British and Metric Units, and Metric and Reduction Tables. 8vo, cloth $ 2 Part II. Iron and Steel. The Ores of Iron ; Methods of Reduction ; Manufacturing Processes ; Chemi- cal and Physical Properties of Iron and Steel ; Strength, Ductility, Elasticity, and Resistance ; Effects of Time, Temperature, and Repeated Strain ; Meth- ods of Test ; Specifications. 8vo, cloth . 3 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 ; Thur- ston’s “Maximum Alloys”; Strength of the Alloys as Commonly Made, and as Affected by Conditions ; The Mechanical Treatment of Metals. 8vo, cloth, 2 “ 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 book for engineers, both civil and mechanical.”— American Machinist. “ We regard this as a most useful book for reference in its departments; it should be in every engineer’s library.”— Mechanical Engineer. Materials of 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, duciility, resistance, and elasticity, effects of prolonged and oft-repeated loading, crystallization and granulation ; peculiar metals ; Thurston’s “maximum alloys”; stone; tim- ber: preservative processes, etc., etc. Many illustrations. Thick Svo, cloth “ Prof. Thurston has rendered a great service to the profession by the publication of this thorough, yet comprehensive, tex^-book. . . . The book meets a long-felt want, and the well-known reputation of its author is a sufficient guarantee for its accuracy and thoroughness.” — Building. Stationary Steam-Engines. Especially adapted to Electric-Lighting Purposes. Treating of the Develop- ment of Steam-engines — the principles of Construction and Economy, with descriptions of Moderate and High Speed and Compound Engines. Revised and enlarged edition. 8vo, cloth 2 “This work must prove to be of great interest to both manufacturers and users of steam-engines.”— Builder and Wood-Worker. 00 50 50 50 OTHER WORKS OF DR. THURSTON. A Manual of the Steam-Engine. A Companion to the Manual of Steam-Boilers. By Prof. Robt. H. Thurs- ton. 2 vols. 8vo, cloth $10.00 Part I. History, Structure, and Theory. For Engineers and Technical Schools. (Advanced Courses.) Nearly noo pages. Fourth edition, revised and enlarged. 8vo, cloth 6.00 Part II. Design, Construction, and Operation. For Engineers and Technical Schools. (Special courses in Steam-Engineer- ing.) Nearly iooo pages. Third edition, revised and enlarged. 8vo, cloth. 6.00 Those who desire an edition of this work in French (Demoulin’s trans- lation) can obtain it at Baudry et Cie., Rue des Saints-Peres, 15, Paris. “We know of no other work on the steam-engine which fills the field which this work attempts, and it therefore will prove a valuable addition to any steam-engineer’s library. It differs from other treatises by giving, in addi. tion to the thermo-dynamic treatment of the ideal steam-engine, with which the existing treatises are filled ad nauseam , a similar treatise of the real engine.” — Engineering and Mining Journal, New York City. “ In this important work the history of the steam-engine, its theory, prac- tice, and experimental working are set before us. The theory of the steam- engine is well treated, and in an interesting manner. The subject of cylinder condensation is treated at great length. The question of friction in engines is carefully handled, etc., etc. Taken as a whole, these volumes form a valuable work of reference for steam-engine students and engineers.” — Engi- neering, London , England. “ The hope with which we concluded the notice of the first volume of this work has been realized, and our expectations in regard to the importance of the second have not been disappointed. The practical aim has been fully carried out, and we find in the book all that it is necessary to know about the designing, construction, and operation of engines ; about the choice of the model, the materials and the lubricants ; about engine and boiler trials ; about contracts. The volume, which closes with an original and important study of the financial problem involved in the construction of steam-engines, is necessary to constructors, useful to students, and constitutes a collection of matter independent of the first part, in which the theory is developed. The publication is a success worthy of all praise .' 1 ' 1 — Prof. Francesco Sini- Gaglia, Bollettino del Collegio degli Ingegneri ed Architetti, Naples. Treatise on Friction and Lost Work in Machinery 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. Copiously illus- trated. 8vo, cloth - 3 “ It is not too high praise to say that the present treatise is exhaustive, and a complete review of the whole subject .” — American Engineer. Development of the Philosophy of the Steam- Engine. i2mo, cloth O 75 “ This small book of forty-eight pages, prepared with the care and precision one would expect from the scholarly director of the Sibley College of Engi- neering, 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. OTHER WORKS OF DR. THURSTON. A Manual of the Steam-Boiler: Design, Construction, and Operation. Containing: — History; Structure; Design — Materials: Strength and other Characteristics — Fuels and Combustion — Heat : Its Production, Measure- ment and Transfer; Efficiencies of Heating-Surfaces — Heat as Energy; Thermodynamics of the Boiler — Steam; Vaporization; Superheating; Condensation — Conditions Controlling Boiler-Design — Designing the Steam-Boiler — Accessories ; Settings ; Proportioning Chimneys — Construc- tion of Boilers — Specifications ; Contracts ; Inspection and Tests — Opera- tion and Care of Boilers — The Several Efficiencies of the Steam-Boiler — Steam-Boiler Trials — Steam-Boiler Explosions — Tables and Notes ; Sample Specifications, etc.; Reports on Boiler-Trials. Fifth edition, revised. 8vo, 879 pages $5 oo Steam-Boiler Explosions in Theory and in Practice, Containing Causes of — Preventives — Emergencies — Low Water — Conse- quences — Management — Safety — Incrustation — Experimental Investigations, etc., etc. With many illustrations, i2mo, cloth j “ Prof. Thurston has had exceptional facilities for investigating the causes ** of boiler explosions, and throughout this work there will be found matter of peculiar interest to practical men, 7 ’ — 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 Prony Brake. Nearly 600 pages. Fourth edition, revised. 8vo, cloth 5 00 (Published also in French, as translated by M. Roussel ; Paris, Baudry et Cie.) •• taken altogether, this book is one which every engineei 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 scattered papers in the transactions of engineering societies, pamphlet re- ports, note-books, etc.” — Railroad Gazette. Conversion Tables Of the Metric and British or United States Weights and Meas- ures. 8vo, cloth . 100 “ Mr. Thurston’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. i2mo, cloth 2 OO From Mons. Haton de la Goupilliere, Director of the Acole Nationale Superieure des Mines de France, and President of La Society d' Encourage- went pour V Industrie Nationale : “ 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.” History of the Growth of the Steam-Engine. (Pub. by D. Appleton & Co., N. Y.) i2mo, cloth 1 75 Heat as a Form of Energy. (Pub. by Houghton, Mifflin & Co., N. Y.) i2mo, cloth J 25 Life of Robert Fulton. (Pub. by Dodd, Mead & Co., N. Y.) i2mo, cloth 75 Digitized by the Internet Archive in 2016 https://archive.org/details/treatiseonbrasseOOthur 483. C. 80 ; T. 20. 481. C. ge ; T. to. 497. C 24.4 ; T. 75.6. 489. C. 56.3 ; T. 43.7- 487. C. 65 ; T. 35. 477. C. TOO. 478. C. 98 ;T. 2. 479. C. 96.3; T. 3.7. “ “ “ 490. C. 51.8; T. 48.2. 488. C. 61.7 ; T. 38.3. A TREATISE ON BRASSES, BRONZES, AND OTHER ALLOYS, AND THEIR CONSTITUENT METALS. PART III. MATERIALS OF ENGINEERING. BY ROBERT H. THURSTON, M.A., LL.D. , DR. ENG’G, Late Director of Sibley College, Cornell University; First President American Society of Mechanical Engineers; Member of American Society Civil Engineers; American Institute Mining Engineers; Society des Ingenieurs Civils ; Verein Deutscher Ingenieure ; Oesterreichischer Ingenieur- und Architekten Verein; British Institution of Naval Architects; Fellow of Am. Assoc, for Advance- ment of Science ; Swedish Academy of Sciences, Etc., Etc., Etc. FOURTH EDITION, REVISED. SECOND THOUSAND.' NEW YORK: JOHN WILEY & SONS. London : CHAPMAN & HALL, Limited. 1910. Copyright, 1884, 1889, 1897, 1900, BY ROBERT H. THURSTON. PRESS OF BRAUNWORTH & CO. BOOKBINDERS AND PRINTERS BROOKLYN, N. Y. PREFACE TO THE THIRD, REVISED, EDITION. THE Author and the Publishers of this work have been agreeably surprised to find that the sale of the several vol- umes of the treatise has been such as to compel the publica- tion of, now, three editions of the part which, it was at the first supposed, would find least demand. They take the opportunity, while issuing this revised edition, to express gratification and appreciation. The work has apparently come to be accepted as standard, and it has become their duty to see that it is kept fully up to the requirements of the profession of engineering, and of those architects and those metallurgists who find a place for it in their libraries and on the list of their reference books. The present edition has been improved by the correction of every error as yet discovered by the writer, the publishers or the readers, both professional and critical; many of whom have taken much trouble to comply with the request printed in the inserted slip, which will be found in every copy, asking for such aid. It has also been given greater value, it is thought, by the introduction of much new matter in the body of the work, under appropriate heads, and by the extension of the appendix ; where will be found some valuable matter relating to recent discoveries and developments in the metal- lurgy of the rarer of the useful metals, such as aluminium and magnesium, and their alloys. It has been a source of gratification to all interested in the work to observe that its contents have proved useful to writers of other treatises on this and allied subjects, and that it has furnished so large a proportion, especially, of the infor- mation given in later publications, relative to the alloys. The very general scrupulousness and courtesy of the authors of such works in crediting their quotations and abstracts to this source is a credit to such writers and a gratification to the Author which is here heartily acknowledged. Sibley College, Cornell University, November io, 1897. PREFACE TO NEW EDITION. In the revision of this volume for an “ end of the century edition ” the author and the publishers have sought to bring the work fully up to date in contents and make-up. The data and statistics have been checked by reference to the latest official reports relative to production, manufacture, and use of the “ Useful Alloys and their Constituents ” ; new illustrations have been introduced ; new and improved processes are de- scribed, and the development of the manufacture of recently introduced and formerly rare metals and their alloys has been traced. The Appendix will be found to contain matter of hardly less value than the body of the book. Advantage has been taken of this opportunity to correct all errors of composition which have been detected, and to repair al* known errors of omission as well as of commission. The aim of author and of publishers alike has been to main- tain the standing of this treatise on the materials of engineer- ing as a work of reference, and to constantly improve it as a standard in its class. The attention of the reader unfamiliar with the older edi- tions is particularly called to the unexampled collection of statistics here compiled relative to the useful properties of these materials ; the tables, especially, containing, it is be- lieved, all needed data relative to all known metals and alloys finding important place in the field of engineering. The metals and compositions employed for bearings and rubbing surfaces generally in machinery of all kinds will be seen to in- clude those now adopted as standards in all departments of VI PREFA CE, construction, and by the engineers and constructors in all parts of the world. The enormously extensive, yet by no means complete, work of the U. S. Board appointed to test the mate- rials of construction, of which Board the author was secretary and editor, as well as member, is fully exhibited and all im- portant facts reported by its committees are here recorded in the most compact form possible, and the index to the volume permits prompt discovery of every desired detail of information. The author and publishers desire to express their full ap- preciation of the favor with which this work has been received by the profession of engineering and by constructors generally, and will endeavor to continue to justify that favor in future editions, should new issues be called for in the future. They reiterate their earlier and repeated request to every reader to assist their work by reporting promptly any error de- tected, and any suggestion that may lead to still further im- provement. CONTENTS CHAPTER I. HISTORY AND PROPERTIES OF THE METALS AND THEIR ALLOYS. ART. PAGE 1. Ancient knowledge of Metals 3 2. Metallurgy, Schedule of Chemical Processes 5 3. Calcination and Roasting 9 4. Smelting 11 5. Fluxes 12 6. Fuels 13 7. Mechanical Processes 13 8 . Working of Metals 14 9. Metal defined 16 10. Useful Metals 16 11. 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 17. Conductivity 21 18. Lustre 24 19. 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 Vlll CONTENTS. CHAPTER II. THE NON-FERROUS METALS. ART. PAG* 29. Copper, History and Distribution 42 30. Qualities of Copper 43 31. 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 41. Ores of Zinc, Smelting 41 42. Metallic Zinc 73 43. Lead 77 44* Ores of Lead 78 45. Smelting Galena 79 46. Commercial Lead 81 47. Antimony 82 48. Bismuth and its Ores 83 49. Nickel and its Ores 84 50. Uses of Nickel 86 51. Aluminium... 88 52. Mercury 90 53. Platinum 92 54. Magnesium 94 55. Arsenic 95 56. Iridium 96 57. Manganese 97 58. Rare Metals 98 59. Commercial Metals, Prices 0 .... 99 CHAPTER III. PROPERTIES OF ALLOYS. 60. General Characteristics 102 61. Chemical Nature of Alloys 104 CONTENTS. IX ART. PAGE 62. Specific Gravity 108 63. Fusibility no 64. Liquation 1 1 3 65. Specific Heat 116 66. Expansion by Heat 116 67. Thermal Conductivity 118 68. Electric “ 120 69. Crystallization 123 70. Oxidation 124 71. Mechanical Properties 126 CHAPTER IV, 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 159 88. Muntz Metal. 160 89. Special Properties 16 1 90. Application in the Arts 162 91. Working Brass 163 92. Properties of Brass 165 X CONTENTS. CHAPTER VI. THE KALCHOIDS AND MISCELLANEOUS ALLOYS. A * T - PAGB 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 180 101. Copper-Nickel Alloys 181 102. “ “ and Zinc (German Silver) 182 103. “ and Iron 183 104. “ “ Antimony 185 105. u “ Bismuth 186 106. “ “ Bismuth; Bismuth-Bronze 186 107. “ “ Cadmium 186 108. “ “ Lead 187 109. “ “ Silicon 187 no. “ “ “ ; Silicon-Bronze 188 in. “ Tin and Lead 188 1 12. “ “ Antimony and Bismuth 188 1 13. “ “ Zinc and Iron 189 1 14. “ and Mercury; Dronier’s Alloy 189 1 1 5 . Complex Copper Alloys 189 1 1 6. Bismuth Alloys 190 1 1 7. “ Tin and Lead ; Fusible Alloys 193 1 1 8. Lead and Antimony 193 1 1 9. Tin “ “ 198 120. “ “ Lead; Fusible Alloys 198 1 21. “ “ Zinc 201 122. Antimony, Bismuth and Lead 202 123. “ Tin “ “ 202 124. “ “ “ Zinc 202 125 “ “ Bismuth and Lead 202 126. Pewter and Britannia Metal 205 127. Iron and Manganese 202 128. Platinum and Iridium 203 129. Spence’s “ Metal ” 204 CONTENTS. xi CHAPTER VII. MANUFACTURE AND WORKING OF ALLOYS* ART. PAGE 130. Alloy of General Use ; Brass Working 205 13 1. 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 215 139. Babbitt’s Anti- friction Metal 515 140. Solders 216 14 1. 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 246 150. Methods of Resistance 247 1 5 1. 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 256 159. Transverse Stress 256 160. Distribution of Resistances 258 1 6 1. Theory of Rupture 259 Xll CONTENTS . ART. PAGE 162. Formulas for Transverse Loading 260 163. Modulus of Rupture 262 164. Elastic Resistance 263 165. Torsional “ 267 166. Strength of Shafts 268 167. Tenacity of Copper 270 168. Tests “ “ 271 169. “ “ Commercial Copper 272 170. Shearing Resistance “ 277 1 71. Resistance to Compression 278 172. Compression by Impact 281 173. Transverse Tests of Copper 284 174. Modulus of Elasticity 286 175. 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 294 180. Tin in Torsion 294 18 1. Strength of Zinc 296 182. Tests of Zinc 297 183. Various Metals 298 184. Wertheim on Elasticity 3 °° 185. Bischoff’s Tests 3°3 CHAPTER IX. STRENGTH OF BRONZES AND OTHER COPPER-TIN ALLOYS. 186. The Bronzes defined 3°6 187. Tenacity of Gun Bronze; Wade’s Experiments 306 188. “ “ “ “ Anderson 308 189. “ “ Bell Metal, Mallett 308 190. Ordnance Bronze in Compression 3° 9 1 91. Hardness of “ (Riche) 3 11 192. Tenacity of Phosphor-Bronze 3 12 193. Resistance “ “ to Abrasion 3 16 194. Strength of Manganese- Bronze. 3*6 195. Manganese-Bronze under Impact 3*7 196. Strength of Ferrous Copper 3*9 CONTENTS : Xlll ART. PAGB 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 325 202. Behavior under Test. 326 203. Appearance of Fractures 330 204. Records of Test 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 2 1 1. “ “ 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 defined 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 XIV CONTENTS. ART. page 232. Resistance to Compression 385 233' “ “ Transverse Stress 387 23*. “ “ Torsion 391 233. “ of Shafts 392 23 6. Records of Tests 393 237. Strain-diagrams of Tension 404 238. “ “ “ Transverse Tests 406 239. Resistances compared 406 240. Resiliences “ 409 241. Elastic Limits u 409 242. Moduli u 41 1 243. 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 414 247. 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. #63. Zinc-Tin Alloys 449 264. Strength and Density 45 ° CONTENTS. xv art. page 265. Grey Ternary Alloys 45 ° 266. Earlier Investigations 451 267 Records of Tests 452 268. 269. 270. 271. 272. 273 . 274. 275 * 276. 277. 278. 279. 280. 281. 282. 283. 284. 285. 286. 287. CHAPTER XIII. CONDITIONS AFFECTING STRENGTH. Conditions modifying Tenacity of Non-Ferrous Metals. . . 476 Heat “ “ “ Copper 476 “ “ “ “ Bronze 477 “ “ “ “ Various Metals 480 “ “ Elasticity 480 Stress produced by Change of Temperature 481 Effect of Sudden Variation “ “ 482 “ “ Chill-Casting 483 “ (( Tempering and Annealing; on Density...... 484 “ “ “ on Tenacity 487 u 66 Temperature of Casting 488 “ “ Time of Loading 489 “ “ Prolonged Stress on Tin and Zinc. . . 492 Effect of Prolonged Stress on Bronze 497 Fluctuation of Resistance 498 Effects of Intermitted and Steady Stress on Resistance. . 500 “ “ “ Stress on Deflection 502 “ “ “ Elastic Limits 508 ‘ ( antimony. B. — Chlorides, Fluorides, etc. Analytic Single decom- position . . . By heating alone e.g. platinum, gold. ” By heating in hydrogen e.g. silver. By action of cheaper metal, etc. - By (a) 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 position ... ( Double de- composition followed by - single de- composition By heating with air e.g. mercury, copper, lead. By heating with cheaper metal, etc. e.g. mercury, antimony, lead. By roasting to oxide and reducing ) as above ) By converting into chloride and ) treating as above ) e.g. iron, zinc, antimony. e.g. silver. D.— Carbonates. po^don° m " | heating with carbon Double de f g roasting to oxide and reducing composition | J ag a ^ 0V e ° sin^°k de^ 1 By conver ^ n ^ into chloride and composition [ treatin S as above . e.g. zinc, sodium, potassium. j- e.g. iron, j- e.g. copper. III. — COMPLEX ORES ; i. e., containing more than one metal. I. Alloy extracted by some or ) e j silver-lead alloy, spie* other process, as above . ... ) ( geleisen. II. Special processes adopted for ) extraction of metals sepa- \e.g. cupriferous pyrites, rately ) 8 MA TE RIALS 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. HISTORY OF THE METALS AND 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 HISTORY OF THE METALS AND THEIR ALLOYS. II 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 other 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 * w 9 t ts. 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 nom metallic constituents of ores. In the removal of sulphur HISTORY OF THE METALS AND THEIR ALLOYS. U 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. 1), hung from the centre, K , and operated by a knee-joint, GEG , 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 OW, 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 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. uoo to 1500 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 “ repousse ” 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 Fig. 1. — Stone-Crusher. HISTORY OF THE METALS AND THEIR ALLOYS. 1 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 “ a 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 vessels 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. 1 7 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 metals 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. 1 9 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 15th 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 18th 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, iridium 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 1.0 Tin 1.3 Zinc 2.0 Worked copper. .... .12 to 20 Cast iron. . . . . Wrought iron. Steel 7 to 12 20 to 40 40 to 100 * 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 i Tin 2 Hard lead 3 Copper 4-5 Alloy for bearings (C.,85; T., 10 ; 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 1, 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 Platinum Palladium Copper Gold Silver Tellurium Bismuth Cadmium Tin Scratch steel. Y Scratched by Calc Spar. Chromium Rhodium Nickel Cobalt Iron Antimony Zinc Lead Potassium Sodium Mercury, j- Scratch glass. >- Scratched by glass. I ) Scratched by the nail. Soft as wax. 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 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 IVa. CONDUCTIVITIES OF METALS. Electric. Thermal. In Vacuo. In Air. Silver 1,000 1,000 1,000 Copper “ commercial 915 748 736 Gold 649 548 532 Brass 240 236 Tin 140 154 145 Platinum 79-3 84 840 Lead 82.7 79 85 Bismuth — 18 The resistance to the voltaic current has been found by Mr. K. Hedges 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 0 C.) TABLE V. RESISTANCES OF METALS TO ELECTRIC CURRENTS. Metal. Resistances as Measured. Before Heating. Change in 24 Hours. ]f, ( nm m errial tin wire 0.815 Ohms. 0.835 0.810 “ 0.860 “ 0.800 “ 0.835 “ 0.820 “ — 0.003 — 0.005 + 0.000 4- 0.000 — 0. 16c 4- 0 000 + 0.0008 9 . T .earl soft 3. Copper, soft /| , Tin-foil pure g t Tin an H lead, 6. Aluminium ( 4< Albo ”) alloy, foil 7» Aluminium and tin * Part II., p. 8, § 10. f Brit. Assoc Reports, 1883, Sec. G. QUALITIES OF THE METALS AND THEIR ALLOYS . 2 3 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 86o° 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 (1 metre) long, and having a cross section of 0.03 inch (1 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 .0154 .0161 100 Copper, A .0171 .0179 90 Silver, A.(i) .0193 .0201 80 Gold, A .0217 .0227 7 i Aluminium, A .0309 .0324 49-7 Magnesium, H .0423 •0443 36.4 Zinc, A., at 350° •0565 • 059 1 27-5 Zinc, H •0594 .0621 25-9 Cadmium, H .0685 .0716 22.5 Brass, A. (2) .0691 .0723 22.3 Steel, A .1099 .1149 14 Tin .1161 .1214 13-3 Aluminium bronze, A. (3) .1189 .1243 13 Iron, A . 1216 . 1272 12.7 Palladium, A .1384 • 1447 11. 1 Platinum, A •1575 .1647 9-77 Thallium • 1831 .1914 8.41 Lead .1985 .2075 77.60 German silver, A. (4) .2654 •2775 5.80 Mercury .9564 1 . 0000 - 1 .61 A, annealed; H. hardened; (i) silver .75; (2) copper 64.2, zinc 33.1, lead 0.4, tin 0.4; (3) 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 86o° 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 2 l for cylindrical bars ; = kdd'l “ elliptical sections ; = kbdl “ rectangular sections. The values of k when / is in feet, other dimensions in inches and W in pounds, are VALUES OF h IN W= kdd'l V/= kbdl. Brass, sheet 2.906 2.618 3-700 3 - 333 4 - 950 3.400 Iron wrought . Lead , sheet 3.888 Steel , soft 2.670 : For pipes, W = k(d 2 — dp) when d x 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, 10th ed., p. 297. 26 MATERIALS OF ENGINEERING— NON-FERROUS METALS . TABLE VI. SPECIFIC GRAVITIES OF PURE METALS. (Water at 6o° Platinum 21.50 Iridium 21.15 Gold 19-50 Tungsten 17.60 Mercury 13-59 Palladium 11.80 Lead 11 .45 Silver 10.50 Bismuth 9. 90 Copper 8.96 Nickel 8.80 Cadmium 8.70 Molybdenum 8.63 '. (15.5 C.) = 1.) 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 0.87 Lithium 0.59 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. 1 | S - G ' LBS. IN CU. FT. kilog’s IN CU. M. Aluminium, cast 2.56 l6o 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 8-5 532 8,500 “ wire 8-54 533 8,540 Bronze * (ordinary) 8.4 524 8,400 Copper,* bolts “ cast 8.85 548 8,850 8.60 537 8,600 “ sheet 8.88 549 8,800 “ wire 8.88 550 8,800 Gold, hammered 19.4 1,205 19,400 “ standard 17-65 1, 103 17,650 Gun metal (bronze) J 8-153 510 8,153 QUALITIES OF THE METALS AND THEIR ALLOYS . 27 TABLE VII. — Continued. NAME. S. G. LBS. IN CU. FT. kilog’s IN CU. M. Iron, cast, from 6-955 435 6,955 “ “ to 7-295 456 7,295 “ “ average 7-125 445 7,125 “ wrought, from 7.560 473 7,56o “ “ to 7.800 488 7,800 “ “ average 7.680 480 7,680 Lead, cast 11-352 710 n,352 “ sheet 11.4 712 11,400 Mercury, fluid 13-6 848 13,600 “ solid 15.632 977 15,632 Nickel, cast 7.807 488 7,807 Pewter 1 1 . 600 725 11,600 Platinum, mass 19-550 1,219 19,500 “ sheet 20.337 1,271 20,337 Silver, mass '. 10.5 655 10,500 4 ‘ standard 10.534 658 io ,534 Steel, hard .' 7.82 496 7,820 “ soft 7 834 491 7,834 Tin,* cast 7-3 456 7,300 Type metal, cast 10.450 653 10,450 Zinc,* cast 7-03 439 7,030 “ sheet 7.29 456 7,290 20. Ductility and Malleability are properties of the met- als scarcely less important to the engineer than that of tenacity. The ductility of a metal or an alloy is its capacity for being drawn out into wire, by being pulled through holes in the wire-drawers’ plates, each hole being slightly smaller than the preceding, until the wire reaches a limit of fineness which is determined by the degree of its ductility, and, as well, by the skill of the workman. Great tenacity, in proportion to the degree of hardness, or high tenacity, a low elastic limit and a certain viscosity, is the combination of qualities required to insure dura- bility. Gold has been drawn until the wire measured but -food inch in diameter, and silver and platinum are nearly as duc- tile. Iron and copper are the most ductile of the common metals. * See text later. 28 MATERIALS OF ENGINEERING— NON-FERROUS METALS. The malleability of a metal, or the power which it pos- sesses of being rolled into sheets without tearing or breaking, is determined by its relative tenacity and softness. The malleability of the non-ferrous metals is determined by their plasticity simply, and this quality is observable in all metals having no defined elastic limit. It is also often determined to some extent by the physical condition of the metal ; thus zinc, brittle in the ingot, is malleable at the boiling temperature of water, and, if worked at that tempera- ture, becomes permanently malleable in the sheet or the bar. Hardening and tempering are operations which can be per- formed on many metals with the effect of modifying their malleability and other properties ; but while sudden cooling from high temperature hardens steel, it softens copper and the bronzes and brasses. Ductility, being dependent upon tenacity largely, is not as generally observed as malleability. Gold is the most malleable of all metals, and has been beaten into sheets of which it would require 300,000 to make up a thickness of one inch. Wrought iron of good quality, and the softer grades of steel, are very malleable ; the former has been rolled to less than of an inch (0.00254 centimetre) thickness. Cast iron and hard steels are neither malleable nor ductile. Copper is very malleable, as well as ductile, if kept soft by frequent annealing ; tin possesses this property, also ; and zinc, although quite brittle when cold, becomes malleable at a temperature somewhat exceeding the boiling point of water ; its temperature being still further elevated, it again becomes brittle, so much so that it may be powdered in a mortar. Some of the copper-tin alloys exhibit the same peculiarity. 21. Odor and Taste characterize many metals. Brass, for example, possesses a very marked taste and perceptible odor when applied to the tongue and when rubbed. These qual- ities may indicate solubility and volatility, but no direct ex- periment has revealed their precise nature. Many of the lighter metals are quite volatile at moderately high tempera- ture. QUALITIES OF THE METALS AND THEIR ALLOYS. 2g Lead can be rolled into quite thin sheets, but it is less malleable than either copper, tin, or the precious metals. The following is a table of the relative ductility of metals: TABLE VIII. ORDER OF DUCTILITY OF METALS. 1. Gold, 4. Iron, 7. Zinc, 2. Silver, 5. Copper, 8. Tin, 3. Platinum, 6. Aluminium, 9. Lead. In the following list, the metals named are placed in the order of their malleability. TABLE IX. ORDER OF MALLEABILITY OF METALS. 1. Gold, 4. Tin, 7. Zinc, 2. Silver, 5. Platinum, 8. Iron, 3. Copper, 6. Lead, 9. Nickel. Prechtl gives the following as the order in which the metals stand in this respect :* TABLE I Xa. MALLEABILITY. DUCTILITY. Hammered. Rolled. Wire-drawn. 1. Lead, Gold, Platinum, 2. Tin, Silver, Silver, 3. Gold, Copper, Iron, 4. Zinc, Tin, Copper, 5. Silver, 6. Copper, Lead, Gold, Zinc, Zinc, 7. Platinum, Platinum, Tin, 8. Iron. Iron. Lead. Authorities differ, however, in their statements in regard to the order of the metals in these respects, and the preceding figures as given in tables are often quoted from Regnault.f * Encyclopaedia Britannica. f Regnault’s Chemistry. 30 MATERIALS OF ENGINEERING— NON-FERROUS METALS. 22. The following table of the principal metals and theil properties is extracted from Watts:* TABLE X. CHARACTERISTICS OF METALS. NAME. % & 0 w w > h O NAME OF DISCOVERER. S. G. SP. HEAT. «; u Q E Q Water = 1. Platinum . . . 1741 1803 Wood 21 . 5 O.O324 O.O326 O.O324 O.O3I9 Iridium .... Descotils 21.15 19. 26 Gold Mercury. . . . 15.60 Palladium . . 1803 Wollaston II.80 O.0593 O.O314 O.057O O.O308 O.O952 O. 1086 Lead H-33 io.57 9 . 80 Silver ...... Bismuth .... Copper 8 . 04 Nickel 1751 1774 Cron sterl f . w • 7T 8.82 Manganese. . Iron Gahn ; Scheele. 8.02 7.84 7-30 7-i3 6.72 O. 1217 O. II38 O.0562 O.O955 O.O508 0.2143 O . 2499 Tin Zinc Antimony . . Aluminium. . 1828 Wohler 2.56 1.74 Magnesium . 1829 Bussey MELTING POtNT. CONDUC- TIVITY. Ther- mal. Elect. 8.4 18. 1200 ° C. (?) — 39 ° C. . . 53-2 CO 6-3 8.5 IOO 1.8 73-5 18.4 8-3 IOO 1.2 99.9 I 3 -I 332 ° C... 1000° C . . . 270° c. . . 1200° C. (?) 2000 ° C. (?) ii - 9 14-5 16.8 12.4 29. 4.6 56.1 41.2 433 ° C... 450° C. . . nr 3 v/ # 4 ^ 3 ° C... TO,} 23. Crystallization is always observed in metal when de- posited from solution or when solidifying from fusion when the conditions are favorable. Gold, silver, copper, antimony and bismuth, and many alloys, as those of copper and of iron, are found in crystalline form in nature. Deposition by the vol- taic current often produces very large and perfect crystals. Lead is precipitated from solutions in beautiful crystalline forms when displaced by zinc. Iron forms well-defined crys- tals when kept heated at nearly the temperature of fusion for a considerable time, and is supposed by some authorities to take on the cubic form when exposed to severe and long-continued jarring. This tendency to crystallization is * Dictionary of Chemistry ; Lond., 1868 ; vol. iii, ; p. 936. QUALITIES OF THE METALS AND THEIR ALLOYS. 3 1 increased by the presence of manganese or of phosphorus. Zinc, in the ingot, is often very distinctly crystalline. The precious metals, aluminium, cobalt, copper, iron, lead and nickel are so nearly amorphous, or if crystalline in struct- ure in their ordinary state, have such small and uniform crys- tals that they may be considered compact and homogeneous. Antimony, bismuth, manganese, and zinc, and some of their alloys often exhibit distinct crystallization, which may also be produced in all metals by prolonged heating or slow cool- ing, and, as supposed by some observers, by long-continued vibration or jarring. 24. Specific Heats. — The effect of heat upon metallic sub- stances in the production of changes of volume and of tem- perature varies considerably. The Specific Heats of a number are given in Table XI.; they measure in thermal units the quantity of heat required to change the temperature of a pound or a kilogramme of the metal one degree. TABLE XI. SPECIFIC HEATS OF METALS. SPECIFIC HEAT. AUTHORITY. Wrought iron . .1138 .IO98 .1150 .12X8 Regnault. Dulong & Petit. <( “ 32 2T2 E . . “ 22 — 2Q2 F “ 22 — *72 F tt “ 32 — 662 F .1255 .1298 .II65 •1175 •09515 .O927 .1013 . I0696 .11714 . 1086 « Cast iron Regnault. <« Steel, soft “ tempered ct Copper a “ 22 — 212 F Dulong & Petit. 22— *72 F Cobalt Regnault. it “ carburetter! « Nickel tt “ carburetter! .1119 •05695 .05623 .09555 .0927 • 1015 tt Tin, English tt “ Indian tt Zinc. tt <( 32 212 F Dulong & Petit. CC “ 32— 572 F 32 MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE XI. — Continued. SPECIFIC HEAT. AUTHORITY. Brass .0939 Regnault. 6 6 Lead .0314 Platinum, sheet • 03243 C 6 “ 32 — 212 F •0335 Dulong & Petit. “ at 572 F .03434 Pouillet. “ “ 932 F .03518 “ “ “ 1832 F .03718 €6 “ “ 2192 F .03818 6 € Mercury, solid .0319 Regnault. 6 6 “ liquid .03332 “ 32 — 212 F •033 Dulong & Petit. “ 32—572 F •035 Antimony .05077 Regnault. “ 32—572 F .0547 Dulong & Petit. Bismuth .03084 Regnault. Gold .03244 Silver .05701 “ 32—572 F .o6lI Dulong & Petit. Manganese .14411 Regnault. Iridium .1887 (C Tungsten .03636 a The following table exhibits the relationship between the combining numbers and specific heats of the metals; the product of specific heat and of combining number is seen to be very nearly constant, as shown by Kopp, who also makes this product, or the “ atomic specific heat,” 6.4 for 42 ele- ments, including all in this table. Kopp also verifies the law of Woestyn and Gamier, finding the specific heat of the molecule equal to the sum of the specific heats of the con- stituent atoms. QUALITIES OF THE METALS AND THEIR ALLOYS. 33 TABLE XIa. SPECIFIC HEATS AND COMBINING NUMBERS. METALS. COMBINING NUMBERS. SPECIFIC HEAT (regnault). PRODUCT Aluminium. . 27 0.2143 5-8 Antimony 122 O.0508 6.1 Arsenic 75 O.0814 6.1 Bismuth 210 0.0308 6-5 Cadmium 112 O.O567 6-3 Copper 63-5 O.O951 6.0 Gold 196 O.O324 6.4 Lead 207 O.O314 6.4 Iron 56 O.II38 6. 1 Magnesium 24 O.2499 6.0 Manganese 55 O. 1217 6.7 Mercury (solid) 200 0.325 6.5 Nickel 59 O.I089 6.4 Palladium 106 O.0593 6.3 Platinum 197.6 O.O329 6.5 Potassium 39 * 1 O. 1695 6.5 Silver 108 O.0570 6.2 Sodium 23 O.2934 6.7 Tin 118 O.O562 6.6 Zinc 65 O.O956 6.2 The specific heats are slightly variable with change of tem- perature. This change has been carefully studied only in a few cases. Holman deduces,* by collating results of experiments published by known authorities, for the specific heat of iron : k = 0.10687 + 0.0000304^° — 32) 4- o. 00000002 3 8 (/ — 32) 2 ) k = 0.10687 + 0.0000547/ 4- o. 0000000428 / 2 J ' ' for the Fahrenheit and Centigrade scales respectively. For platinum he obtains: k = 0.0328 4- 0.000003022^— 32) 4- 0.000000000009 ( t — 32 ) 2 f k — 0.0328 4- 0.00000544/ 4- 0.0000000000 1 6/ 2 , or, very nearly, k — 0.03208 4- 0.00000304 (/ — 32) k = 0.03208 4- 0.00000547/ (2) * Journal Franklin Institute , August, 1882. 3 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 AUTHORITY. 32 °F.(o°C.) AND 2I2°F.(lOO°C.) Glass Copper Brass Iron Steel (untempered) . . . “ (tempered) Cast Iron Lead . . Tin Silver (fine) Gold Platinum Zinc 0.000872 to 0.000918 0.000776 to 0.000808 0.001712 to 0.001722 0.001867 to o 001890 0.001855 to 0.001895 0.001220 to 0.001235 0.001079 to 0.001080 0.001240 0.001 109 0.002849 0.001938 to 0.002173 0.001909 to 0.001910 0.001466 to 0.001552 0.000884 0.002976 Lavoisier and Laplace. Roy and Ramsden. Lavoisier and Laplace. 4 < i< Roy and Ramsden. Lavoisier and Laplace. 4 4 (6 i i Roy and Ramsden. Lavoisier and Laplace. << a << (6 <4 «< Dulong and Petit. Daniell. QUALITIES OF THE METALS AND THEIR ALLOYS , 35 Chaney 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 Xlla . EXPANSIONS OF SOLIDS. For i° F. For i° C. Authority. Aluminium, cast 0.00001234 0.00002221 Fizeau. “ cryst 0.00000627 0.00001 129 6 C Brass, cast 0.00000957 0.00001722 Sheepshanks “ plate 0.00001052 0.00001894 Ramsden. “ sheet 0 . 00000306 0.00000550 Kater. Bronze, Baileys, Cop., 17 ; tin, 25 ; zinc, 1. 0.00000986 0.00001774 Clarke. Same 0.00000975 0.00001775 Hilgard. Copper 0.00000887 0.00001596 Fizeau. Gold 0.00000786 0.00001415 Chandler & Roberts. Iridium 0.00000356 0.00000641 Fizeau. Lead 0.00001571 0.00002828 “ Mercury (cubic expan.) 0.00009984 0.0001 797 1 Regnault & Miller. Nickel 0.00004695 0.0000125 1 Fizeau. Osmium 0.00000317 0.00000570 a Palladium 0.00000556 O.OOOOIOOO Wollaston. Pewter 0.00001 129 0.00002033 Daniell. Platinum 0 . 00000479 0 . 00000863 Fizeau. “ 90 ; iridium, 10. . . . 0.00000476 0.00000857 a “ 85; “ 15.... 0.00000453 0.00000815 i * Silver 0.00001079 0.00001943 Chandler & Roberts. Tin 0.00001163 0.00002094 Fizeau. Zinc 0.00001407 0.00002532 Baeyer. “ 8, tin 1 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, Z', 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 l printed for the House of Commons, London, 1883. 36 MATERIALS OF ENGINEERING — NON-FERROUS METALS . IOO for Fahr. scale, . for Cent, scale, . where a is the coefficient given above. TABLE XIII. . . (3) (4) EXPANSIONS OF VOLUME. PER DEGREE CENT.* o° C. (32 0 F.) to IOO° 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 .000089 .0084 to .0089 Tin .000058 to .000069 .0059 to .0069 Zinc .000087 to .000090 .0087 to .0090 Brass .000053 to .000056 .0053 to .0056 Steel .000032 to .000042 .0032 to .0042 Cast Iron about .OOOO33 .0033 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 490 254 Lead 630 332 Zinc 700 37 i Silver 1,280 693 Brass 1,870 1,021 Copper 2,550 1,118 Cast Iron 2,750 1,510 Wrought Iron 4,000 (?) 2,201 (?) 38 MA TE RIALS 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. Silver. ...... Copper Gold Cast Iron . . . Pure Iron, Nickel, Cobalt, Manganese, Palladium, Molybdenum, Uranium, T ungsten, Chromium, Titanium, Cerium, Osmium, Iridium, Rhodium, Platinum, Tantalum, F. C. + 1873° + 1023 9 1996 1091 2016 1102 2786 1530 ? Highest heat of the forge. Do not melt in the forge. F. C. Mercury -39° -39°. 8 Rubidium + 101.3 + 38.5 Potassium 144-5 62.5 Sodium 207.7 97.6 Lithium 356 180 Tin 442 227.8 Cadmium 442-5 228 Bismuth 497 259 i Thallium 561 294 Lead 617 325 Tellurium 615 (?) 324 Arsenic ? ? Zinc 773 412 Antimony red heat. Fusible only in «■ Oxyhydrogen flame. Latent Iicat . — 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 dib * 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 25-65 Bismuth 12.64 22.75 Lead 5-37 9.67 Water 79-25 142.65 Silver . . 21.07 37-93 Cadmium 13.66 24-59 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. 4 1 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 20 to 25 “ Antimony 20 to 25 “ Copper 2 to 2.5 “ Tin 1 to 1.5 “ Mercury 1 to 2.5 “ Silver 0.0005 to 0.0010 per cent. Platinum 0.0001 to 0.0002 “ Gold 0.000001 to 0.00001 “ 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 as yet known 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. (1 121 0 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 225,000 to 250,000 tons are annually * “ Prehistoric Times.” fVol. i. p. 12 (Ed. 1856.) 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 ORES. 45 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 0 — 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 CuC 0 3 , CuH 2 0 2 , yielding, when pure, 57-33 P er 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. Azurite (blue carbonate of copper) — composition, 2 CuC 0 3 , CuH 2 0 2 — 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 . Chalcociie (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 about 200,000 or 300,000 tons annually. The output in 1845 was but 100 tons,* that in 1899 was about 600 millions of pounds (nearly 325,000,000 kilogs.), valued at 15 cents per pound, or over $50,000,000, 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. f 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. 4 7 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+ Cu 2 0 = S0 2 + Cu 6 ) 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 birch poles. This last process of refining is the only one necessary in the treatment of the native copper of Lake Superior. Argen- tiferous ores, as those of Montana, are now extensively re- duced by electrolytic methods, electric currents of enormous volume being supplied by dynamos of large capacity. Gold and silver are in some instances thus produced in consider- able quantity as a “ by-product ” and at no important expense. 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, mel ting ta 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 4 . 50 MATERIALS 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,” 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. 51 carbons and the pure carbon of the wood. Overpoling causes the absorption of bismuth, and gives the same brittleness 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 rem 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. 11. 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 1 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 (1 1 5 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-f S 0 2 CuO + S 0 2 = Cu+ SOo. 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 f 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. 1. Per cent. NO. 30. Per cent. Metallic iron 0.020 0.014 0.035 none none none none trace 87.900 12.086 none 0. 014 0.057 0.014 none none none trace 96.330 3.580 Metallic zinc Metallic silver Metallic arsenic Metallic antimony Metallic tin Metallic bismuth Metallic lead Metallic copper Suboxide of copper Carbon 100.055 99-995 No. 30 had been less exposed to the air than No. 1 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 silicon, also, 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 1 5 kgs. per sq. cm.), as the per- centage of phosphorus added rises from one to three or four per cent. Arsenic, in small doses, hardens copper. 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 5 6 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 metals. Electrolytic copper is very pure and constitutes about half the total production. 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 99.80 0-39 0.00 99-83 0.15 0.00 99-65 0.00 Oxveen Sulphur 0.00 Silver 0.05 0.01 0.026 0.066 Lead 0.016 0.044 0.088 Arsenic 0.00 0.00 Antimony. 0.00 0.00 0.035 Silver in 2,000 pounds. , 100.25 14.6 100.02 7.03 99.893 19-75 A sample of Swiss copper, found by Berthier $ to possess extraordinary softness, ductility, and malleability, was com- posed of Copper 99.12 Calcium.... 0-33 Potassium 0.38 Iron 0.17 and that author concludes that its valuable properties are * Trans. Inst. Min. Engineers, vol. x., p. 63. \ Ibid., p. 54. J “ 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 indies; feed and “ blow-off ” pipes are usually thus made; this “ solid-drawn ” pipe is more costly, but much better, than brazed 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 by soldering or brazing, or by riveting. Welding is practicable with a flux of one part sodium phos- phide, two of boracic acid. 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 lbs. per sheet. 2 \ “ 5 “ 9 to 150 “ “ 3 “ 5 “ 16 to 300 “ “ 4 _ “ 6 “ 16 to 300 “ “ Sheathing 14 inches. 48 inches. 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 0.3212 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- ured. 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 T Vth 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 lbs. per capita). Copper is, when cast, rendered sound and strong by the use of phosphorus as a flux. Abel, in i860, 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 attaininga 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, i860. RELATIVE DIMENSIONS, LENGTHS, RESISTANCES, AND WEIGHTS OF PURE COPPER WIRE 62 MATERIALS OF ENGINEERING— NON-FERROUS METALS. 3-4°35 • 0I 4 I02 6 I 9-°q8 54*354 > 286.99 I 18.398 I. 0034845 1 1739.40 ‘ I -7394° » .329432 I -5749 11 I 3*°3553 .0x05772 [ 94.543 16882 COPPER TELEGRAPH WIRE. 63 Pure copper weighs 555 lbs, per cubic foot. The resistance of one mil-foot at 6o°. Fahr. is, according to Dr. Matthiessen, 10.32411 Ohms. Upon these data the above table has been calculated. The resistance of copper varies with the temperature at about 0.38 percent, per degree Centigrade, or 0.21 per cent, per degree Fahr. Stranded Wires, — A stranded conductor of a given length is of greater weight and has a less resistance than an equal length of the same number of wires unUranded. 64 MATERIALS OF ENGINEERING— NON-FERROUS METALS. 37. Tin {Stannum ; 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 “ 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 about 20,000 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 0 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 useless 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 byre-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 1 16; 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. 67 The coefficient of expansion is 0.000023 ; its melting point is 443 0 Fahr. (232 0 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. Lead 0.165 Iron O.035 Manganese o . 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 . . . . I 2 I 2 I 2 I 2 Tin Iron 99.961 O. OI9 0.014] 0.006 99.9 0.2 99.96 98.64 93-50 0.07 95-66 0.07 1-93 99.9 99-59 98 . 18 Lead 0.20 2 . 76 Copper O.24 O. l6 0.406 1.60 Antimony .... 3-76 2-34 Bismuth L . ... O. I 1 1 * Metalhuttenkunde, 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 excellent 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 20,000 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 is 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 . 7 O 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 1900, about 125,000 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 0 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. ORES 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- 7 2 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. I CONSTANTINE. CAVALO. BLUESTONE. AMERICAN. Zinc IO.64 I3.4O 29.28 27.20 Lead 4.81 17.14 12.90 12.00 Copper 1-35 O.44 O.65 0.20 Silver and Gold 0.04 0.06 0.03 Sulphur 26.85 15-37 22.14 Iron 19-93 4.98 7.16 Alumina 2-33 1.02 Magnesia. 0.22 .... Barium sulphate 35-04 Silica .... 26.48 11. 19 26.84 Arsenic 0.65 0. 13 0.15 Lime 0.60 O.84 .... Sulphuric Acid 3-53 .... .... Antimony 0.02 .... Oxygen and loss 2.77 1 .01 I. OI 100 . 00 100.00 100.00 — 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 500° 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 : 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 extern THICKNESS AND WEIGHT PER SQUARE FOOT. Inch. .0311 = IO OZ, .0457 = 12 OZ, Inch. .0534 = 14 oz. .0611 = 16 oz. Inch. .0686 = 18 oz. .0761 = 20 oz. METALLIC ZINC. 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 ?6 MATERIAL. £ OF ENGINEERING— NON-FERROUS METALS. rolls kept heated by the passage through them of steam ot 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 120,000 tons (1899), and the production is rapidly increasing. At least one-half comes from Illin- ois, 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 considerable 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 4-5 1-3 5.8 Bergen Point 5-5 I.9 7-4 Lehigh 4-5 1-7 6.2 Carondelet 4.4 1 . 2 5-6 The yield of zinc is stated to be Lehigh, for calamine 73-5 per cent. Lehigh, for blende 70.0 “ Passaic, for calamine 80.0 “ Martindale, for blende and silicates 73.0 “ Carondelet, for silicates 76.80 “ Of the whole quantity consumed in the United States in 1899, 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. (32 y° 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 0 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 [ 2 PbC 0 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 MA TE RIALS 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, z>., 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. 8l 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 to 7 feet (2 to 2 ]/^ 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 0.1 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 ENGINEERING-NON-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 (1899) of about 220,000 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 ; Sbi), 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. It injures brass seriously. 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 8 4 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 (Ni. ; 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, Canada now 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. Large quantities come from New Caledonia. 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. 85 A. B. Garnierite. Noumeite. Silica 48.21 40.35 47-23 47.90 Iron and alumina oxide. . . . 1.38 1-33 1.66 3-oo Nickel oxide 23.88 29.66 24.01 24.00 Magnesia 19.90 21.70 21 .66 12.51 Water 6.63 7.00 5-25 12.73 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. Garnierite . 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. According to Mr. Nursey, most of the nickel made in the United States is produced by what is known as the Thomson soda process. Matte of first fusion is freed from iron by sub- sequent roasting and smelting. It is then smelted in a cupola furnace with sodic sulphate and coke. The product of this fusion when drawn off separates, whilst fluid, by gravity, into two portions, a lighter and a heavier, which are separable when cold. The lighter part, known as “tops,” contains nearly all the soda, copper, and iron, whilst the heavier por- tion, called “ bottoms,” contains nearly all the nickel. As the separation of nickel and copper is not quite complete the bottoms are treated over again, substantially in the way we have described, until nickel sulphide of satisfactory purity is obtained. Metallic copper is ultimately produced from the tops, the very small quantity of cobalt present going with the nickel and there remaining. The nickel sulphide when dead roasted, becomes nickel oxide, which is considered to be suf- ficiently good for use in the manufacture of nickel steel. To 86 MATERIALS OF ENGINEERING— NON-FERROUS METALS. produce shot nickel, nickel oxide is reduced, melted, and poured into water. In this form the metal assumes a good appearance, but it is not approved of for delicate uses. By reducing, melting, and moulding the oxide, rough slabs are formed, which, treated as anodes, yield electrolytic nickel of high quality. The French company, Le Nickel, melts the nickel silicate of New Caledonia with gypsum, thus producing matte consist- ing of nickel sulphide and iron sulphide. By successive roast- ing and smelting, the iron is entirely removed as slag, and a final dead roasting produces nickel oxide of the requisite purity to yield, by reduction, good merchantable metallic nickel. Some part of this nickel oxide is sold as oxide to steel makers and others. The Manhes converter is the invention of Mr. Peter Manhes. Taking the matte just referred to, he concentrates it by blowing air through it, when melted, in a basic lined converter, thus removing all the iron. After clearing off the slag he desulphurizes the metal by continued fusion in the converter with lime and lime chloride. The pure nickel goes to the bottom of the converter and is teemed into moulds for the market. 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 0.01 inch USES OF NICKEL. 8/ (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-steel, Fe. 75, Ni. 25, is non-corrodible. 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. It has come to be extensively employed in alloy with steel for armor-plate, giving enormous shock-resisting power. 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. 1. NO. 11. NO. III. a . b . a . b . a . b . Carbon •530 •549 1 . 104 1.080 1.900 1.830 Silicon •303 .294 .130 .125 •255 .268 Iron .464 •463 .108 .110 .301 .318 Cobalt . - . .446 .438 trace trace .... Sulphur .049 •057 . 266 •340 . 104 .096 [Nickel] 98 . 208 98.199 98.392 98-345 97.440 97,488 Total 100.000 100.000 100 . 000 100.000 100.000 100.000 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 (A/.; 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 for ALUMINUM; OR , ALUMINIUM. 89 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. Devilie 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. Aluminium is made by Hall’s process of solution of alu- mina (bauxite) in a bath of molten cryolite (a double fluoride of sodium and aluminium) and of electrolysis by a heavy cur- rent of low voltage (2.8 to 4). This remarkable and impor- tant invention transferred the metal from the class of rare to that of useful metals and reduced its cost to less than copper and brass, bulk for bulk. [See Appendix.] 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. Devilie made a bell of but 44 pounds (20 kilogs.) weight, which was, however, one and a half feet in diameter ( y 2 metre), and exhibited an go 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. Some 3,000 tons per year are now (1899) so used. [See Appendix.] Alloys of aluminium with other metals, with the excep- tion of copper and zinc, are not in much use. There are several manufactories of the metal producing considerable quantities of product. 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 ft 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, o°, 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 metak MERC UR V 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 761 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 (1 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 lbs. (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 g2 MATERIALS OF ENGINEERING— NON-FERROUS METALS r . 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 (/V.) 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 iridium. 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 PLA TIN UM. 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, 0.000001 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. Chloric acids dissolve it. 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 carnellite , 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 45 ° • 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. [See Appendix: Magnesium as Constructive Material.] 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 iridium, 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 Iridium 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 2 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 is produced electrolytically like aluminium. 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 “ spiegcleisen ,” an alloy with iron used in the * Proc. Ohio Mechanics’ Institute, 1882. f A?n. Chemical Journal , vol. v. No. 4, 1883. 98 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 compari- 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 20 to 80 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 tm. Its sulphide, known as cadmium yellow, is bright in color and has qualities of great value to artists. The metal Is of little use. Dentists make with it alloys and amalgams. 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 resembles aluminium, though lighter and un- tarnishable. It excels iron in strength, and copper in con- ductivity. 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 does not tarnish by exposure. Rhodium is white, very hard and infusible. Its specific gravity is about 11. Ruthenium resembles iridium. 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 9.4. 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. Chromium has similar uses. 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 IOO MATERIALS OF ENGINEERING— NON-FERROUS METALS. especially advisable when the engineer selects metals or 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, mainly from Bolton,* may be taken as representing approximate values. Prices of Metals. METAL. STATE. VALUE IN GOLD PER LB. AVOIRDUPOISE. PRICE IN GOLD, I9OO. AUTHORITY. Vanadium. . Cryst. fused $4,792.40 $ 480 S. Rubidium Wire 3,261.60 2,400 S. Calcium Electrolytic 2,446 20 1,920 s. Tantalum Pure 2,446.20 T,68 4 s. Cerium Fused globule 2,446.20 1,920 s. Lithium Globules 2,228 . 76 960 s. Lithium Wire 2 , 935-44 1,440 s. Erbium Fused. 1,671.57 1,920 s. Didymium ( 6 1,630.08 2,880 s. Strontium Electrolytic L 576.44 1,920 s. Indium Pure 1,522.08 720 T. Ruthenium 1,304.64 1,500 T. Columbium Fused 1,250. 28 450 s. Rhodium 1,032 . 84 1,000 T. Barium Electrolytic 924. 12 500 S. Thallium 738 . 39 QUO T. Osmium 652 . 32 12 T. Palladium 498.30 600 T. * Engineering and Mining Journal , Aug. 21, 1875. THE PRICES OF METALS. 101 Prices of Metals. — Continued. METAL. STATE. VALUE IN GOLD PER LB. AVOIRDUPOISE. I PRICE IN GOLD, I9OO. AUTHORITY. Iridium $4.66 . SO $480 T. Uranium. . 434.88 240 T. Gold tJt 299.72 2 ' 9 Titanium Fused 239.80 360 .... Tellurium < € 196.20 150 .... Chromium 6 i 196.20 175 .... Platinum < < 122.31 250 .... Manganese 108.72 100 T. Molybdenum 54-34 50 T. Magnesium. ...... Wire and tape 45-30 1.05 T. Potassium Globules 22.65 8 T. Silver 18 . 60 13 Aluminum * Bar 16.30 .30 S.” Cobalt Cubes 12.68 5 s. Nickel < ( 3.80 -35 T. Cadmium . 3 . 26 3 T. Sodium 3.26 j 1 T. Bismuth Crude i -95 1 S. Mercury 1 .00 1 Antimony •36 .20 T. * Tin .25 . 23 Copper * .22 .18 Arsenic . 15 OS Zinc j . 10 .06 oc Lead .06 Iron • oi£ .OI The prices of many may be considered also as “ fancy prices,” and a whole pound of some of the metals named could hardly be obtained at even these figures. In compiling the table, the prices of the rarer metals are obtained from Trommsdorff’s and Schuchardt’s price lists; the avoirdupois pound is taken as equal to 453 grammes, and the mark as equal to 24 cents gold. It is evident that the prices of the metals bear no relation to the rarity of the bodies whence they may be derived ; for calcium, the third in the list, is one of the most abundant elements. * The price of copper fell in 1885-86 to 10 cents per pound, rising- in 1887 somewhat, aluminium (i8g6) has dropped to 50 cents or less ; magnesium to $5; nickel to 25 cents a pound ; silver to 50 cents an ounce ; platinum, $6 ; while ’ead and zinc cost 3 and 4 cents a pound. CHAPTER III. PROPERTIES OF THE ALLOYS * 6o. Properties of Alloys. — The Author, before entering upon the researches directed by the Committee on Metallic Alloys of the United States Board, and before making a series of experiments on the characteristics of alloys, as a proper introduction to the work instituted a somewhat exhaustive examination of the records of earlier experiments in this direction. The result of this investigation has been to reveal a vast amount of information on the chemical and physical proper- ties of the alloys ; but such information is widely scattered, and authorities do not always agree. Some experiments have been made upon alloys made from the impure commercial metals, others from metals rendered chemically pure for the purpose. Again, the apparatus used has not always been of the same degree of accuracy, and this has produced another cause of disagreement. These differences, however, are usually slight. It is evident that alloys, being composed of metallic bodies, will possess all the physical and chemical characteristics of metals ; they have the metallic lustre, are more or less ductile, malleable, elastic, and sonorous, and conduct heat and elec- tricity with remarkable facility. In retaining these proper- ties, however, the compound is so modified in some of its qualities, that it often does not resemble either of its con- stituents, and might, consequently, be regarded as a new metal, having characteristics peculiar to itself. This is espe- cially the case with those which are used in the arts. It would * Prepared originally, in large part, and with the assistance of Mr. Wm. Kent, M.E., for the Committee on Metallic Alloys of the United States Board, appointed to test, iron, steel, and other metals. See Report, Vol I., 1878. PROPERTIES OF THE ALLOYS. 103 almost seem that there is no department of the arts requiring the use of metals for which an alloy may not be prepared possessing all the requisite qualities, when these are not found in the original metals.* The physical properties of an alloy are often quite different from those of its constituent metals. Thus copper and tin mixed in certain proportions, form a sonorous bell-metal, possessing properties in which both metals are deficient ; in another proportion they form speculum metal, which is as brittle as glass, while both of the constituent metals are ductile. It is impossible to predict from the char- acter of two metals what will be the character of an alloy formed from given proportions of each. In most cases, how- ever, it will be found that the hardness, tenacity, and fusi- bility will be greater than the mean of the same properties in the constituents, and sometimes greater than in either; while the ductility is usually less, and the specific gravity is some- times greater and sometimes less.f The color is not always dependent upon the colors of the constituent metals, as is shown by the brilliant white of speculum metal, which con- tains 67 per cent, of copper. Very slight modifications of proportions often cause very great changes in properties. M. Bischoff £ states that he can detect the deteriorating effect of one part tin upon ten million parts of pure zinc, and the writer has found half of a per cent, of lead to reduce the strength of good bronze nearly one- half and to affect its ductility to an almost equal extent. It is not a matter of indifference in what order the metals are melted in making an alloy. Thus, if we combine 90 parts of tin and 10 of copper, and to this alloy add 10 of antimony ; and if we combine 10 parts of antimony with 10 of copper, and add to that alloy 90 parts of tin, we shall have two alloys chemically the same, but in other respects — fusibility, tenacity, etc. — they totally differ. In the alloys of lead and antimony, also, if the heat be raised in combining the two metals much above their fusing points, the alloy becomes harsh and brittle. * Muspratt’s Chemistry, vol. 1, p. 533. f Ure’s Dictionary, vol. 1, pp. 46-50. \ British Assoc. Reports, 2, 1870, pp. 2og, 210. 104 MATERIALS OF ENGINEERING— NON-FERROUS METALS. Some metallic alloys are much more easily oxidizable than the separate metals. An alloy of tin and lead heated to red- ness takes fire and continues to burn for some time.* In regard to certain physical properties, Matthiessenf remarks that the metals may be divided into two classes: Class A . — Those metals which impart to their alloys their physical properties in the proportion in which they them- selves exist in the alloy. Class B . — Those metals which do not impart to their alloys their physical properties in the proportion in which they themselves exist in the alloy. The metals belonging to class A are lead, tin, zinc, and cadmium ; and those belonging to class B, in all probability, all the rest. The physical properties of alloys may be divided into three classes : I. Those which in all cases are imparted to the alloy approximately in the ratio in which they are possessed by the component metals. II. Those which in all cases are not imparted to the alloy in the ratio in which they are possessed by the component metals. III. Those which in some cases are and in others are not imparted to the alloy in the ratio in which they are possessed by the component metals. As types of the first class, specific gravity, specific heat, and expansion due to heat maybe taken; as types of the second class, the fusing points and crystalline form; and as types of the third class, the conducting power for heat and electricity, sound, elasticity, and tenacity. 61. The Chemical Nature of Alloys. — The chemical nat- ure of alloys has long remained a disputed point among scient- ists. The question, “Are alloys definite chemical compounds, solutions, or mechanical mixtures?” is not easily answered. Several authors give their views and describe their methods of making experiments to settle this question, but there still * Lire’s Dictionary, vol. i, p. 49. f Jour. Chem. Soc., vol. 5, 1867, pp. 201-220. PROPERTIES OE THE ALLOYS. 105 remains a wide difference of opinion in regard to it. Most writers now agree, however, in considering some alloys as chemical compounds and others as mixtures, but they differ as to whether any particular alloy is the one or the other. Thus Calvert and Johnson * consider the tin-copper alloys definite compounds, while Matthiessenf claims that they are “ solidified solutions of one metal in the allotropic modification of the other.” Muspratt J says: Many alloys consist of simple elements in definite or equivalent proportions, while others are produced from compound bodies, and often the components do not exist in the ratio of their chemical equivalents. Metals, in forming alloys, do not, however, combine indiscriminately with one another; the union is governed by the greater affinities which some of them manifest for each other ; just as, in the chemistry of bases and acids, a predisposing attraction determines a preference. This in some measure proves that the alloys are not mechanical mixtures, but definite chemical com- pounds. It is remarkable that the native gold found in auriferous sands and rocks is alloyed with silver in the ratio of one equivalent of the latter to four, five, six, eight, ten, etc., equivalents of the former, but the combinations never afford results indicative of the metal being united in fractional parts of an equivalent. Muspratt further says that another proof of the chemical combination subsisting is, that the compound melts at a lower temperature than the mean of its ingredients; but Mat- thiessen § argues that this is no proof. Watts 1 remarks that most metals are probably to some extent capable of existing in combination with each other in definite proportions ; but it is difficult to obtain these com- pounds in a separate condition, since they dissolve in all pro- portions in the melted metals, and do not generally differ so widely in their melting or solidifying points from the metals * Phil. Trans., 1858, p. 363. f British Assoc. Rep., 1863, p. 47. X Muspratt’s Chemistry, vol. 1, p. 534. § British Assoc. Rep. 1853, p. 42 ; also, Jour. Chem. Soc., vol. 5, 1867, p. 207. I Watts’ Dictionary, vol. iii. p. 942. 106 MATERIALS OF ENGINEERING— NON-FERROUS METALS. they may be mixed with as to be separated by crystallization in a definite condition. The chemical force capable of being exerted between different metals may, as a rule, be expected to be very feeble, and the conse- quent state of combination would therefore be very easily disturbed by the influence of other forces. But in all cases of combination between metals, the alteration of physical properties, which is the distinctive feature of chemical combination, does not take place to any great extent. The most unquestionable compounds of metals are still metallic in their general physical characters, and there is no such transmutation of the individuality of their constituents as takes place in the combination of a metal with oxygen, or sulphur, or chlorine, etc. The alteration of characters in alloys is generally limited to the color, degree of hardness, tenacity, etc. Messrs. Calvert and Johnson, about the year i860, made a long series of experiments on alloys and amalgams made with pure metals, with the hope of throwing some light upon the subject, and of solving the question “ Are alloys mixtures or compounds ? ” They believe that they have succeeded in ascertaining: First, the influence which each additional equivalent quantity of a metal exerts on another ; secondly, the alloys which are compounds and those which are simple mixtures; for compounds have special and character- istic properties, while mixtures participate in the properties of the bodies composing them. They hold that the bronze alloys are definite compounds ; for each alloy has a special value of conductivity of heat, and also its own specific gravity, and its own rate of expansion or contraction ; while, on the contrary, the alloys of tin and zinc are mixtures; for they conduct heat, have a specific gravity and expand according to theory, or according to the proportions of tin and zinc which compose each alloy. Calvert and Johnson’s con- clusions are chiefly based upon their experiments on the heat conductivity of the alloys. Later experiments, made by Matthiessen,* on the conducting power of electricity, led him * British Assoc. Reports, 1863, pp. 37-48. PROPERTIES OF THE ALLOYS. 107 to different conclusions. He experimented upon upwards of 250 alloys, all made of purified metals. The results of his investigations are published in a paper, “On the Chemical Nature of Alloys,” from which is transcribed the following classification of the solid alloys, composed of two metals, according to their chemical nature. 1. Solidified solutions of one metal in another : The lead-tin, cadmium-tin, zinc-tin, lead-cadmium, and zinc-cadmium alloys. 2. Solidified solutions of one metal in the allotropic modifi- cation of another : The lead-bismuth, tin-bismuth, tin-copper, zinc-copper, lead-silver, and tin-silver alloys. 3. Solidified solutions of allotropic modificatio 7 is of the metals in each other : The bismuth-gold, bismuth-silver, palladium-silver, plat- inum-silver, gold-copper, and gold-silver alloys. 4. Chemical combinations : The alloys whose composition is represented by Sn 5 Au, Sn 2 Au, and Au 2 Sn. 5. Solidified solutions of chemical combinations in one all- ot her : The alloys whose composition lies between Sn 5 Au and Sn 2 Au, and Sn 2 Au and Au 2 Sn. 6. Mechanical mixtures of solidified solutions of one metal in another : The alloys of lead and zinc, when the mixture contains more than 1.2 percent, lead or 1.6 per cent. zinc. 7. Mechanical mixtures of solidified solutions of one metal in the allotropic modification of the other : The alloys of zinc and bismuth, when the mixture con- tains more than 14 per cent, zinc or 2.4 per cent, bismuth. 8. Mechanical mixtures of solidified solutions of the allo- tropic modifications of the two metals in one another: Most of the silver-copper alloys. Matthiessen, however, does not claim that the above classification is not liable to exception. He was obliged to assume that some of the metals undergo a change, or are 108 MATERIALS OF ENGINEERING— NON-FERROUS METALS. converted into an allotropic modification in the presence of another metal, in order to explain some of the phenomena which he observed, but he admits that until the allotropic modifications have been isolated, the assumption must re- main an hypothesis. To conclude, we can only say that the question is still unsettled. From the marked peculiarities of properties observed in a few of the alloys, we are led to pronounce them chemical compounds. Some others, we must admit, are simple mixtures, or rather, solidified solutions. But in regard to the large majority we are still in doubt. Further experiments may throw more light on the subject, but it is probable that with the larger number of alloys it will be found impossible to discover their exact chemical nature. 62. Specific Gravity.— The specific gravity of an alloy is rarely the mean between the densities of each of its constit- uents. It is sometimes greater and sometimes less, indicat- ing, in the former case an approximation, and in the latter a separation of the particles from each other in the process of alloying. This subject has been studied by several writers, and their published results agree quite closely in regard to some of the alloys, but differ in regard to others. These differences may be accounted for by the differences in the apparatus used by the experimenters, by the fact that some determinations have been corrected for temperature and pres- sure of the atmosphere, while others were not ; but principally from the fact that several of the alloys are liable to be very deficient in homogeneity, and that the density of the same alloy will vary according to the conditions under which it is formed, as being cast too cold or too hot, cast in iron or in sand moulds, etc. A bar cast in a vertical position is apt to have a greater specific gravity at the bottom of the bar than at the top. Repeated fusion of an alloy also causes changes in its density. It is common among authorities who publish determina- tions of specific gravities of the alloys, to give the calculated as well as the observed specific gravity. The calculated specific gravity is that which the alloy would have if there PROPERTIES OF THE ALLOYS. IO9 were neither expansion nor condensation of the metals during the act of combination. The specific gravities should be calculated from the volumes and not from the weights. Dr. Ure* gives the rule as follows: Multiply the sum of the weights into the products of the two specific gravity numbers for a numerator, and multiply each specific gravity number into the weight of the other body and add the products for a denominator. The quotient obtained by dividing the said numerator by the denominator is the truly computed mean specific gravity of the alloy. Expressed in algebraic language the above rule is — M _ ( w + «/) Pp ~ Pw + p W’ where M is the mean specific gravity of the alloy, W and w the weights, and P and p the specific gravities of the constituent metals. Clarke’s compilation of the “Constants of Nature,” pub- lished by the Smithsonian Institution, contains a full table of specific gravities of the alloys, with the names of about twenty-five authorities. Of these, the principal are Mallet, Calvert and Johnson, Matthiessen, and Riche. The following table of the alloys whose density is greater or less than the mean of their constituents, is given by several writers : TABLE XVIII. ALLOYS OF ABNORMAL DENSITY. Alloys, the density of which is greater than the mean of their constituents. Gold and zinc. Gold and tin. Gold and bismuth. Gold and antimony. Gold and cobalt. Silver and zinc. Silver and tin. Silver and bismuth. Alloys, the density of which is less than the mean of their constituents. Gold and silver. Gold and iron. Gold and lead. Gold and copper. Gold and iridium. Gold and nickel. Silver and copper. Iron and bismuth. * Ure’s Dictionary, 6th ed. 1872, vol. 1, p. 92. HO MATERIALS OF ENGINEERING— NON-FERRO US METALS TABLE XVIII .—Continued, Alloys, the density of which is greater than the mean of their constituents. Silver and antimony. Copper and zinc. Copper and tin. Copper and palladium. Copper and bismuth. Lead and antimony. Platinum and molybdenum. Palladium and bismuth. Alloys, the density of which is less than the mean of their constituents. Iron and antimony. Iron and lead. Tin and lead. Tin and lead. Tin and palladium. Nickel and arsenic. Zinc and antimony. Calvert and Johnson agree with Matthiessen in giving the density of the alloys of lead and antimony as less than the mean of the constituents, and Matthiessen shows the alloys of lead and gold to have a greater density than the mean of their constituents. Some alloys of tin and gold and of bis- muth and silver are shown by Matthiessen to have a greater, and some a less, density than the mean of their constituents, and the same is true of the alloys of some other metals. 63. Fusibility. — A remarkable property of many of the alloys is their great fusibility. In nearly all cases the fusing point of an alloy is lower than the mean of its constituent metals, and in some instances, as in the so-called fusible alloys, it is lower than that of either. The cause of this fact has not been definitely ascertained. Some regard it as a proof that the alloy is a distinct chemical compound, but most authorities differ from this view. Matthiessen* sup- poses that chemical combinations may exist in the fused mass, which suffer decomposition on cooling or solidifying. He says that the low fusing points admit of explanation by assuming that chemical attraction between the two metals comes into play as soon as the temperature rises, and the moment the smallest portions melt, then the actual chemical compound is formed which fuses at the lowest temperature, and then acts as a solvent for the particles next to it, and so promotes the combination of the metals where this can take place. * British Assoc. Reports, 1863, p. 42. PROPERTIES OF THE ALLOYS. Ill In another place* Matthiessen remarks that all mixtures have a lower fusing point than the mean of the substances forming the mixture ; for instance, salt-water solidifies below zero, and a mixture of the chlorides of sodium and potassium fuse at a lower point than the mean of the fusing points of the components. Some alloys have been observed to fuse at one point and solidify at a lower one ; for example, the tin-lead alloys, which all solidify at 181 0 C., but the fusing point of which varies with the different proportions of the component metals from 181 0 C. to 292 0 C. Concerning these alloys, Pillichodyf remarks as follows: When the points of solidification are observed by immersing the thermometer in the melted alloy, it usually exhibits, during the passage of the mass from the liquid to the solid state, two stationary points. This effect is due to the separation of one or other of the component metals, while an alloy of constant composition still re- mains liquid. This alloy corresponds to the composition Sn 3 Pb. An alloy richer in lead would first deposit lead, and an alloy con- taining a larger proportion of tin would first deposit tin — the alloy Sn 3 Pb remaining liquid for a longer or shorter time, and ultimately solidifying at 181 0 C. This temperature, therefore, corresponds to the lowest melting point that can be exhibited by an alloy of tin and lead, a larger proportion of either metal causing the melting point to rise. With the exception of the alloys of tin and lead, and the fusible alloys, the fusing points of but few of the alloys have been determined. An accurate pyrometer for temperatures above red heat is needed for this purpose. The “ Constants of Nature,’’ while it has the specific gravities of several hundred alloys, gives the melting points of only six, exclusive of the fusible alloys and those of lead and tin. Mallet^: gives the relative fusibility of the several alloys of copper and tin and copper and zinc, and shows that their fusibility in- creases regularly as the proportion of copper in the alloy diminishes. * Jour. Chem . Soc., vol. 5, 1867, p. 207. f Ibid., vol. 15, 1862, p. 30. \Phil. Mag., vol. 21, 1842, pp. 66-68. 1 12 MATERIALS OF ENGINEERING— NON-FERROUS MR TALS, Some alloys in passing from the liquid to the solid state do not change at once, but remain for some time in a pasty condition. Their temperature of solidification, therefore, cannot be distinctly recognized. This is the case with an alloy of the composition Bi 2 PbSn 2 , which is fusible in boil- ing water, but which remains in a pasty condition through an interval of several degrees of temperature, so that it can be handled like a plaster. M. Person * made experiments upon the alloys Bi 3 Pb 2 Sn 2 (D’Arcet’s alloy, fusible at 96° C.), Bi 2 PbSn 2 (fusible in boil- ing water), and BiPbSn 2 (fusible at 145 0 C.), and formed the conclusion that it is possible to assign in advance the heat necessary to fuse an alloy, if that required to fuse each of its component metals is known. He gives the formula (160 + / ) ^ — /, in which t is the temperature at which fusion is effected ; for example, 332 0 C. for lead if melted alone, but only 96° C. if melted in D’Arcet’s fusible alloy ; / is the ex- penditure of heat necessary to produce the fusion, that is, a certain number of calories (1 calorie — 3.96 British thermal units) variable with t ; $ is the difference of the specific heats of the liquid and solid. If t and / are known, $ can be found. In the case of tin, t = 235, / = 14.3, from which % — 0.0362. Having this value of 3 , it is easy to calculate the heat neces- sary to melt tin at any temperature whatever, for instance at 96° C., for which we find 9.3 cal. Making the same calcula- tion for bismuth and for lead we find 7.382 and 2.7 cal. It only remains to take these numbers in the proportion in which each metal exists in the alloy, which gives a little less than 6.3 calories , which differs from the number found by experiment (6 cals.) only 0.3 cal. Nothing appears to have been written upon this branch of the subject since M. Person’s paper was published, but it is probable that if the investigation was pursued further our knowledge of the causes of the remarkable fusibility of th 6 alloys would be much increased. M. Riche f has determined the melting points of certain * Comptes Rendus, vol. 25, 1847, pp. 444-446. \ Ann. de Chim . , vol. 30, 1873, p. 351. PROPERTIES OF THE A FLOYS. 113 alloys of tin and copper, by means of Becquerel’s thermo- electric pyrometer. He obtained concordant results with the alloys SnCu 3 and SnCu 4 , but with all other alloys the results differed widely among themselves. W. C. Roberts,* chemist to the British mint, has published a series of determinations of the melting points of several alloys of silver and copper. The temperature was estimated by finding the amount of heat contained in a WTOught-iron cylinder of known weight which was dropped into the melted alloy while in the furnace, and removed as soon as the mass showed signs of solidifying. The specific heats of the iron and of the alloy were the data used in the calculation. The alloy, composed of 630.29 parts of silver and 369.71 parts copper, corresponding to the formula AgCu, showed the lowest fusing point, or 846.8° C. ; that of pure copper being 1 330° C., and that of pure silver 1040° C. 64. Liquation. — Many of the alloys exhibit the phenom- ena of liquation, or separation of the mass of melted metal in the act of solidification into two or more alloys of different composition. The resulting alloy, or mixture of alloys, is con- sequently deficient in homogeneity. The causes of this separation are as yet but imperfectly understood. Some observations seem to show that an alloy of constant com- position and of a comparatively high fusing point solidifies first in crystals disseminated throughout the mass, while the remainder of the melted metal remains fluid for a longer time, and finally solidifies around and among these crystals. This fact would tend to prove that the first alloy solidified was a distinct chemical compound, but it has been shown that crystals of exactly the same appearance have been formed from two metals in a wide range of proportions. The different circumstances under which the separated alloys may be formed, such as the heat of the metal when poured into the mould, and the fact of slow or of rapid cooling, are known to have some influence upon the amount of liqua- tion, or the difference of composition of different parts of the same casting, but this influence is not exerted upon all alloys 8 *Proc. Roy. Soc., vol. 23. 1875, pp. 481-495. 1 14 MATERIALS OF ENGINEERING— NON-FERROUS METALS . in the same direction, some alloys being affected in one way and some in another by the same manner of treatment. The bronze alloys, such as gun-metal, are said to have the liqua- tion diminished by rapid cooling. When the mass is cooled slowly, bronze castings often show in the interior what are called spots of tin, but which are really spots of a white alloy of copper and tin, containing a larger percentage of tin than the average of the whole casting. When slowly cooled, also, the bottom of the casting is often found to contain a larger percentage of copper than the top. When cooled rapidly, however, as shown in the experiments of General Uchatius* in casting cannon in chilled moulds, the liquation is reduced to a minimum, and the resulting alloy is more homogeneous. Levol t made some experiments on the liquation of the alloys of silver and copper, and concluded that the only homogeneous alloy of these two metals was the one whose composition is 718.97 parts of silver and 281.07 parts of cop- per, corresponding to the formula Ag 3 Cu 2 , and that all the others are liable to more or less liquation. It has lately been shown, however, by Mr. W. C. Roberts, J chemist to the British mint, that this alloy is only homogeneous when cooled rapidly. If the cooling is slowly effected, its homogeneity is disturbed, the external portions being slightly richer in silver than the centre. Mr. Roberts made several determinations of the liquation of other alloys of silver and copper, and found that the arrangement of an alloy is to a great extent dependent on the rate at which it is cooled, and that several alloys of silver and copper are, under suitable conditions, as homogeneous as Levol’s alloy. The alloy of 925 parts silver and 75 parts copper was found to be nearly homogeneous when cooled very slowly, the composition of the corners and centre of a cube 45 millimetres on a side showing a maximum difference of only 1.4 parts in 1,000, while the same when cooled rapidly showed a difference of 12.8 parts in 1,000. * Ordnance Notes No. xl, Washington, D. C., 1875. f Ann . de Chim. y vol. 36, 1852, pp. 193-224. \ Proc. Roy. Soc., vol. 23, 1875, pp. 481-495. PROPERTIES OF THE ALLOYS . 1 15 Col. J. T. Smith * relates, in reference to some experiments made by him on the alloy of silver and copper containing 91^3 per cent, of silver, that the separation of the constituent parts of the alloy was not so much due to the rapidity or slowness with which the heat of the fluid metal was abstracted, as to the inequality affecting its removal from the different parts of the melted mass in the act of consolidation. Thus, if a crucible full of the melted alloy were lifted out of the furnace and placed on the floor to cool, the surface of the melted metal within it being well covered with a thick layer of hot ashes, the lower parts of the mass after it had become solid would be found to contain less silver in proportion than the upper surface. If, on the other hand, the crucible were left to cool while imbedded in the furnace, the upper surface being exposed to the air, then the lower parts would, after solidification, be found finer than the upper surface. Riche f has made several experiments on the liquation of the alloys of copper and tin. He remarks that to manifest the property of liquation, it is necessary to agitate the crucible containing the melted alloy, at the moment of solidi- fication, in order to separate the small crystals already formed. The results obtained on the last product, remaining liquid in a mass weighing 1,000 to 1,200 grammes, showed a remarka- ble liquation of all the alloys of copper and tin except those corresponding to the formulae SnCu 3 and SnCu 4 Several other alloys exhibit like phenomena to an even greater extent than those above mentioned. Matthiessen and Von Bose experimented upon alloys of lead and zinc and bismuth and zinc, melting the metals together in various proportions, and found that one end of a bar would have an excess of one metal and the other end an excess of the other. Alloys of copper and lead containing an excess of lead show a liquation in a remarkable degree, the excess of lead partly oozing out from the mass on cooling. * Proc. Roy. Soc., vol. 23, 1875, PP- 433-435- f Comptes Rendus , vol. 67, 1868, pp. 1138-1140, and vol. 30, 1873, pp. 35I-4I9- II 6 MATERIALS OF ENGINEERING— NON-FERROUS METALS. 65. Specific Heat. — The published determinations of the specific heat of the alloys are not numerous. This results, not from any difficulty of making the observations, but probably because they have not been considered of such practical importance as those of other properties, and partly, also, because M. Regnault’s* determinations, made in 1841, and his deductions therefrom, are accepted as final. M. Regnault determined the specific heat of two classes of alloys ; first, those which at ioo° C. are considerably re- moved from their fusing points ; and, secondly, those which fuse at or near ioo° C. The specific heats of the first series were so remarkably near to that calculated from the specific heats of the component metals that he announced the fol- lowing law : “ The specific heat of the alloys, at temperatures considerably removed from their fusing point , is exactly the mean of the specific heats of the metals which compose them.” The mean specific heat of the component metals is that obtained by multiplying the specific heat of each metal by the percentage amount of the metal contained in the alloy and dividing the sum of the products for each alloy by 100. A curious fact discovered in regard to these alloys is also that the product of the specific heat of each alloy by its atomic weight is sensibly constant, varying in the whole series only from 40.76 to 42.05. The second series of alloys, or those which fuse at a temperature at or near ioo° C., show a wide divergence from the above law, the specific heats of all of these being much higher than that calculated from their constituents. The product of the specific heats by the atomic weights varied also from 45.83 to 72.97. Matthiessen f describes a simple arrangement of the dif- ferential thermometer for the purpose of showing that the specific heat of an alloy is the same as the mean of those of its components. 66. Expansion by Heat. — The expansion of the alloys by * Ann. de Chim ., vol. 1, 1841, pp. 129-207. f Jour. Chem. Soc., vol. 5, 1867, p. 205. PROPERTIES OF THE ALLOYS. 117 heat has been examined by Messrs. Calvert and Lowe,* with a view to learn whether their expansion followed the law of the proportions of their components. Four series of alloys were examined, namely, those of zinc and tin, lead and anti- mony, zinc and copper, and copper and tin. In each case the expansion was less than that deduced by calculation from their equivalents. In alloys of copper with tin, it was found that where only a small quantity of tin entered into the composition of a bar, the expansion fell considerably below that of pure copper, although the tin added has a much higher rate of expansion than copper. From experiments made by Messrs. Calvert and Lowe upon the expansion of chemically pure metals, they conclude that a very small proportion of impurity has a marked in- fluence upon the expansion. Their results differed largely from those of other experimenters who used only the com- mercial metals ; but when they, too, used commercial metals, the results agree. The alloys upon which they experimented were also formed from pure metals, and on account of the difficulty of procuring these in sufficient quantity, the bars experimented on were very small, being only 60 millimetres, or less than 2^2 inches long. The apparatus used, however, as described at length in the Chemical A T ews, was so sensitive, that an ex- pansion of •5-y-Jxro °f an inch could readily be observed. If experiments were made upon alloys formed from the ordinary commercial metals, it would probably be found that their rate of expansion would differ considerably from that of alloys formed from pure metals. The molecular condition of a metal was observed to have an important influence on the rate of expansion. The same will no doubt be found true in the case of alloys. Matthiessen + states that the expansion due to heat of the metals takes part in that of their alloys approximately in the ratio of their relative volumes. He gives a table of the * Chem. News , vol. 3, 1861, p. 315. f Jour. Chem. Soc., vol. 5, 1867, p. 206. 1 1 8 MATERIALS OF ENGINEERING— NON-FERROUS METALS expansion of several alloys which tends to confirm his state* ment. 67. Conductivity for Heat. — The power of the alloys to conduct heat has been examined with great care by several experimenters. The published results are not always con- cordant, but the differences may be partially accounted for by the various kinds of apparatus used, and the great influence which small impurities and changes in molecular condition and crystalline form exert upon conductivity. The conducting power for heat in an alloy is found in some cases to be the mean of the conducting power of the component metals, and in others to apparently have no relation whatever to such mean. As examples of the first case may be cited the alloys of tin and zinc and tin and lead; and of the second, the alloys of gold and silver and gold and copper. From this circumstance it has been expected that the heat- conducting power could be used as a means of determining whether an alloy is a chemical compound ora simple mixture. As before stated, however, the authorities differ widely on this point. Messrs. Weidemann and Franz,* in 1853, made some experiments on the conducting power of the metals and of a few of the alloys, using a thermo-electroscope as an appa- ratus. In 1858, Calvert and Johnson t made an extensive research on alloys formed from pure metals, using an apparatus of their own invention, by which the relative conducting power was shown by the rise in temperature in a given time of a given volume of water secured in a box at one end of the bar, while the other end of the bar was heated to 90° C. They claim that the method which they employed gave such consistent results, that they were able to determine the influence exer- cised on the conducting power of the metals by the addition of 1 or 2 per cent, of another metal, and also to appreciate the difference of conductivity of two alloys made of the same metals and only differing by a few per cent, in the relative * P°gg' Annalen, vol. 89, 1853, pp. 497-531. f Phil. Trans., 1858, pp. 349-368. PROPERTIES OF THE ALLOYS. 1 19 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 1 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 1 Cu and 2 Sn, 1 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 1 Pb, 4 Bi and 1 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 1 Sn 2 Cu, 1 Sn 3 Cu, etc. In this case each alloy has its own arbitrary com 120 MA TE RIALS OF ENGINEERING— NON-FERROUS ME 7 ALS. 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 Annalen , vol. 10S, 1859, pp. 393-406. £ Jour. Chem . Soc . , yol. 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 ioo, pure silver being ioo. 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 eithet 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 t^e 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., i860, pp. 85-92. f Phil. Mag., vol. 4, 1834, p. 27. X P°gR- 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: “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.” T 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 i860, 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., i860, pp. 161-176. \ Phil. Trans., 1864, pp. 167-200. § Phil. Trans., 1858, pp. 369-381. S Phil. Trans., i860, pp. 85-92. T 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 2 , 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 J 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. ^ Proc. Roy. Soc., i 86 o -’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. 125 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. f Ibid., vol. 10, 1855, pp. 250, 251 ; also, Jour. Chem. Soc. f 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 any other of the bronzes. Three alloys, viz., Cu l8 ZnSn, Cu I0 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 chemischen 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 ALLOYS. 127 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,;): 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 3 ^ 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,” 1 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. \ “ Report of Experiments on Metals for Cannon,” Phila. , 1856. \ Ordnance Notes No. XL., Washington, D. C-, 1875. § Phil. Mag., vol. 21, 1842, pp. 66-68, | 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 . I29 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. 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 “ 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 both preceding and closely following the Christian era : DATE. COPPER. ZINC. TIN. LEAD. IRON. Large brass of the Cassia family. . B. C. 20 82.26 17-31 -35 “ “ Nero “ A. D. 60 81.07 17.81 1-05 “ “ Titus “ .. “ 79 83.04 15.84 -50 “ “ Hadrian “ “ 120 85.67 IO.85 1. 14 1-73 -74 “ “ Faustina “ .. “ 165 79.I4 6.27 4-97 9. l8 -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 and iron. 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 ac cording 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. 1. Chisel, from ancient Egyptian quarry. 2. Bowl, from Nimroud 94.00 89.57 5 - 9 ° 10.43 H -33 9-58 II . 12 .10 Wilkenson. Dr. Percy. 3. Bronze overlaying iron 88.37 89.69 88.05 81.19 4. Sword-blade, Chertsey, Thames •33 J. A. Phillips. Prof. Wilson. 5. Axe-head 00 00 ' 6 . Celt 18.31 7. Roman As, b.c. 500 69.69 7 Q I T 7. 1 6 21 . 82 • 47 •57 J. A. Phillips. 8. Tulius Caesar 8.00 12.81 /y * O 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 Senor 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 ! it is malle- * “ Prehistoric Times ; ” London and New York, 1872. f A r . A. Review, 1875 ; Ruins of Central America. J 34 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 coppef 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 about 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 9 7 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 ENGINEERING— NON-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. , COMP. I COPPER. S. G. COLOR. FRACT. TENACITY. MALL. HARD. FUS. Cu Sn : 0 per ct. IOD. 8.607 red-yellow 'Tons per sq. in. 24.6 I IO 16 a 10 : : 1 84.29 8.561 fine grain 16. 1 2 8 15 b 9 J : 1 82.81 8.462 yellow-red 15.2 3 5 14 c 8 : : 1 81 . 10 8-459 44 17.7 4 4 J 3 d 7 : : 1 78.97 8.723 pale red vitreous 13-6 5 3 12 e 6 : r 1 76.29 8.750 “ 9-7 brittle 2 11 f 5 : : 1 72.80 8-575 asli gray conchoid. 4.9 44 1 IO g 4 : : 1 68.21 8.400 dark gray 0.7 friable 6 9 h 3 : : 1 61.69 8.539 white gray 44 0-5 7 8 i 2 : 1 5 r -75 8.416 white lam. grain x *7 brittle 9 7 j I ; : 1 34-92 8.056 vitreous 1.4 11 6 k 1 : : 2 21.15 7-387 lam. grain 3-9 8 tough 12 5 l 1 : 3 T 5 - T 7 7*447 4 ‘ 3 - 1 !3 4 m 1 : : 4 11.82 7.472 U 3-i 6 44 H 3 n 1 ; : 5 9 63 7.442 U earthy 2-5 7 J 5 2 0 0 ; : 1 0 . 7.291 2.7 16 1 a , 3 , c are gun-metals ; d , hard brass for pins ; e, f g, h , z, bell-metal ; j\ k , for small bells ; /, z/z, zz, •001 = aaA • • vo • • cr> . Tj- . 00 VO — Xjs ‘ifjiDTJjoap * . ff) # • • G\ • N o» joj AjiAijonpuo^ • • • VO • •001 = J3AJIS ‘jBaq ; . M . . . vo • • • joj XjiAijDnpuo3 • - 00 • • CO • • • ’(J 31 P 5 J\[) I % l Ajqiqisnj jo japjQ I • vo • • CPIltfjSp liqBOjiBui jo .iap-iQ •(uosuqof pUB JJ3A[B3 pUB l 13llBJ\[) SSaup-IBJI •(uojsjnqx) •XjI[I}Dnp OAlJBpjJ *0 3 lI B K) Xjqijonp jo aapjQ I •qoui ojBnbs aad spunod ‘Xjiobuox g € | 53 •AjiabjS oypads t^OO VO Os 00 00* 00 oo" >>.W ,Q t n O rt •£ C O' Ov 00 00 00 O' t" VO O' oo’ oo’ !»■« rt nO' NO OHO 8 0 o’ o O 0 O 6 o’ 00 00 00 00 t^vo vo vo’ in j 5 - OOOOOOOOO'O'OiOiO'O' O' Ov OvOvOv •Bjnuuoj Diuiojy •jaqum^ ro unvo t^oo oiO " « «■ S'g BRONZES AND OTHER COPPER-TIN ALLOYS. 151 £ 6 S-B SS § 5 g'g a & 0.0O v is sim sl^la fflc/ 3 WO 00 n 1 C rt — : £ * 3 Iri Se u 0 Yijg .13 . •2 rt. , . - . rt C . . aS lC? 2— 3' »h O h a H 3 1 ! O'—: u — : t-i 6 ^ a ^ a $ tj 03^ s s S U %>» 33 .33 rt > > _ mIL- 7 ’ sisl^ H 9 C a .3 ii aj X 2 i> o •V a ,0.0.3 c/0-3 • a c/3 c/3 ~ cp4£ o ^T-S" .fflffl pQ , . p5 ffl . ^wtflri^ripQm^pqJnfflpq'cn q ^ “ £ N sgS^S 00 o 0 0 <8 : : vo as 00 00 00 00 rovo 00 00 10 00 00 00 ON On On ON O nci N N - MHHMMOOOO( O' On On O' On On O' On O' On O' On On On < 5 ? 8 O'. O' O' ON 00 00 00 00 fv' OOOOOOOOOOOOOOOOOOCOl 1-1 O' co O' O' 3 3 uu c c 73 C/5 ■ loco C^OO O' O h ci « b (i n con .33 ... •uu • • • • : c c : : : • • C/3 C/3 . ■ . . mvo r^oo O' O 1 S*7 I PROPERTIES OF ALLOYS OF COPPER AND TIN. 152 MATERIALS OF ENGINEERING— NON-FERROUS METALS. in sj .5 a §je 03 rt o 03 *“ S tn G o) < M G « 73 XS *J U • C ‘52xi * 0,2 .5 G5 >NM £ 88 p rt .$2 .c>c £ U CO •Ajuoqjny m caw mrigc/idgign JgS pq>'sH E> £ • 00 : = J3A -jis ‘Ajpujoap joj AjiAipnpucQ ■001 = j3ATis ‘jnaq joj AjiAip'npuo;} IN 0 Cl 'CPIFW) Ajqiqisnj jo jop-io • • • CO Cl H ' 0 3 ll B M) M] -I{qB3l[BUI JO J3PJO N • • • 0 H Cl •(uosuqof PUB JJ3A[B3 PUB *J3IIBJ\[) SSOUpjBH m * . • ^ ro « Broke •(uojsanqx) Ajqijonp OATJBp-g : °" ; 0 o' 5*8 o' o’ •(I3JFK) Ajqipnp jo Jopao m i ’ • Tf m 0 •qoui 3JBnbs jod spunod ‘Ajtobuox 00 0 • Th O • 0 « • 4 vO~ I • ro rn • • 00 . VO ! Os . ro 35,739 0 00 (£ ro NO O" ro 24,650 22,010 00 IN Cl Fracture. Fine cryst. Fine cryst. Fine gran. Vitr. conch. Fine gran. Smooth Vitreous Color. Reddish yel., 2 Reddish gray "O :K ■13 > Reddish gray Yel’wishred, 1 Pinkish gray Bluish red Reddish white •AjiabjS ogpads Cl Cl N ON ro VO ON 0* VO 10 10 tN On 00 i- On N co 00 00 00 00' 00* 00 O m 0 s> iO lO t*- (N 00 ON in 0 00 00 00 00 ~ 00 0 ci ON IN 00 00 rN m 0 ^ H VO H lOw osm os n h 00 00 00 00 0 O in in invo 00 00 01 00 00 CO Composi- tion by- analysis. c CO . in • 10 • Os • 00 • . 00 Cl ro Cl 6 U ' 6 • 00 • m • ON • O* 00 VO VO* till Sn. 0 0 on 0 0 m 0 0 in m 0 00 on VO VO In IN 00 00 00 Q OO Q O 0 00 CO O 0 00 O' h- 0 0 Q On O 5 000 O 00 Os 0 O mv o vo Inoo 00 0 0 h 0 OOO O O O 0 0 Cl rorororo mNN Cl N Cl * d' s 0 a Cu. 0 0 O 0 m 0 0 rooo m O h h ^ ro ci ci ci m m 00 00 00 00 00 00 CO Q QOO O O Cl NO O Cl h ON 0 O Q h o 0 OOO O N 0 OnO inrOfON Cl CM O O' O' h 0 0 0 0 on on co oo in vo vo vo vo in m ci cm 00 00 00 00 00 NNNNNNNNN N N M- N •B[nuuoj oiuiojy : : 3 • ' g 5 3 • -u ■ -uu : : : : : : s’ : - 3 r 1 1 : : : p a . ... . ;UU ;U cju : • ; uu . : g : : c g ■ -co • • co c n : ::: ::cc::ccc: : c a c/) c/3 • -cnc/ic/j . cncn •aaquin^ BRONZES AND OTHER COPPER - TIN ALLOYS . 153 S i £ 'o •« c 3 2 ffi Vh CQ .com gc/)l/j«g’[ .CQ ?C/3 § ffl ■ cqcq cqcq cqcqcq cqcq CQ c/3 (g: 42 c/3 c/3 c/3 gpqc/jc/ic/i UD UUU CQ . _CQ U |3 ro 00 88 8 8 8 o o o On 00 ON Th IO OVO* 10 O 00 O ®, ? ^ nN m cti n3 Ki 2 -03 o 'o *S J 3 .3 -C 000 c c c 000 UUU oj a .'H.'H 00 .GjG o o C G O O uu . 5 U U «2 S C /5 L >>c. a! H £2 > J 5 P» t/5 <5 bjo , 3 _- > « i> , 3 2 O I* •G-fj;- C/5 ._ •G >> 5 rt J 3 2 £ SI u o 10 ON ON 00 00* 00* r^vo Th o rh »n iovo O' O' On On On m rov 8 'w in in m rj- e* OJ rovo On N h m On 0 0 0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r^oo 00 00 & m o o 'O n m m n rn < 1 co CO co co co co co aj O n fo VO vo 50 vo ts o H* 0‘ «5 SO ' N Q M N 0 00 00 ^ 00 00 00 C^VO VO vr N h h h t-v s* S-vo vovovovovovovovovovovovovo 10 vo in CO co CO CO .3 3 3 3 uuuu . C C C C •C/3 C/5 C/3 1/3 3 3 3 3 ;UUU U . C C G C •C/3 C/3 C/3 C/5 3 3 3 3 3 uuuuu C C G C G C/3 C/3 C/5 C/5 C/5 ■«f mvo s.00 OOOOO • 3 -33 ;U .UU C/3 -C/5 C/5 -C/5 mvo s.00 O' 0 3 3 3 3 3 UUUUU G C C 3 C C/3 C/3 C/3 C/3 C/3 HHHHHHHHNNNNN 67.50 I j 7-931 TABLE XX. — Continued . 154 MATERIALS OF ENGINEERING— NON-FERROUS METALS. QC •s'! si (U (fl •Ajuoqjny •OOI = J3A “[IS ‘AjpUJD3[3 joj AjiAipnpuo;} I •OOI = J3AJIS ‘JB31[ I joj AjiAijo'npuo;} I Ajqiqfsnj jo japjQ •[[qB3[[Bui jo aopjQ •(uosuqof pire JJ3A[B3 pire ‘J3[IBJ\[) SS3UPJBH •(uojs.inqx) Ajqrpnp oAijep^j Ajippnp jo jopaQ •qoui ojtenbs jod spun’od ‘Ajpeuox tv^O co m m tv 0 Tt-oo N ^ Ov iOO}N vo vo* ro rf CO VO CO 5 cn >4 u U >. 4> u £ o U U rtU o U a) 3-S C w rt a5 o w •Ajiab-iS DTjioods "S >-« o,n 35 a- >. G o’rt o-- G tj rt Si £ £* .1 JG 3 « J3 J • • « •jjj W .i ’S* p o m o 00 in com . , H M fO N ( Ov OVOO CO tv ' Tf tvco m ov tv tv COO VO N Is N N N \n sn moo n o in't'tiomo m (n co no ‘ -- ‘ “ “ ■ 10 10 in 10 ^ 10 in ' NNNlstsNNNNNtstsNN '35 13 P as-s? 6 o£>* 3* 0 a co O O (N O VO c* m o vo m 01 h n min tv 00 0 s tv o vo H H me* m m m iv tv vo inmininw . ov 0 h >-< Ov Ov O' O' O' tv -cinuijoj oimoiy . . 3 . : 3 3 3 3 s : •333 33 13 3 3 3 3 3 3 3 1 ’• : :u : ; uuuuu : ;UUUU •uuuuuuuu : : : : c : : c c c c g‘ : : g' sf G s ic'c'c'c’cccc : : c/2 • • c /2 c /2 c /2 c /2 c /2 • • C/2 C/2 C/2 C/2 • C/2 C/2 C/2 C/2 C/2 C/2 C/2 C/2 • • "jaquin^ ir ,'0 f^OO O' O H N ro ■ 7*4 T 7 BRONZES AND OTHER COPPER-TIN ALLOYS. 155 05 PQ PQ PQ 05 rt ctf ctf l > 4 ) !>. ON OOO 00 loro-t co^O rS 3 3 o S* a s a 0 fc in o co m tj- m 0 Os O Os o os o ON N N P) N O t^. t>s I CO lO t^oo O 00 Q 00 Q 0 oosoooooooooo ~ 10 H 0 0000000 3.33 u :uu VO VO ' s '§ -s ^ PL, > M d Js a •J ~ is 2 * a s .. 8 30 Q 10 § -I a ^ w m . co ' is U S E> t> •Ooi = J 3 AJIS ‘Aipupap aoj XqiiAponpuo3 • VO • • ro • 79-3 • m • • in • w • •OOI = J 3 AJTS ‘}B 3 q joj AjiAxpnpuo5 00 VC co • • • N • •(*»n*w) Ajqiqisnj jo japjo 10 S CO • Oi •(uosuqof pire jj3A[B3 pue I 3 IIBJM) ssaupjHH c 5 0 CO 3 0 j a •( 13 IPK) M] -jiqBOneui jo JopJO ! H CO 11 10 •(uojsjnqx) Ajqipnp OAijep-ji 00 • 0 • CO • O' 00 37-9 O' VO Ajippnp jo aapjQ •qoui 34nnbs jod spunod ‘Ajpuuox tn . £ c3 T3 __ o> ‘55 re g g,°.S§ So--* <3'^°a E 3 I a OOOOOOOON it, tj- io m « n o) N lovo t-'OO o\ o\ o\ o o o 8 0 0 0 0 0 0 0 \NN r> vnroNNWwOOOO Ov» oo OOOOOOC'O'O' O' 0'0>CTi<7>CTiCT><^0'Q> OOO 00 00 <1.0 a a NN c o 3 3 uu BRASSES AND OTHER COPPER-ZINC ALLOYS. l6j 6 -Sc ^ o 2 2 £0 ts ba V..3 O CQUU pq cq .pq . .d . .pq .oq . . . .pq . , .pq . .pq • s' oJ 6 6 d " 6 • o o 6 o r"" * l— > o' • .3 o’ • o’ - os 1—1 o -odd -do • o’ o’ o’ — < .* h— > tflJSj^pqpqpqSgpq'flpqpqpqpQSjpqWEg-pqwgjgpqc/ifflC/jpqg ^ pqcflpqpqpq^pq^pqcqpqScjj E> £ £>£>£>£> t> £> £> O OO CM VO OV V-I ^ iS u* 3 u .a >, Su'd >.s £ w g SI •a £ ^ 2 £ ■d 2 'tf-vo OO OO VO VO OO OO N ro 1- OOOOOO moo ro -vj-oo oo t^vo vo’ vo’ vo’ VO 3 3 UCJ 3 3 NN 3 3 3 NNN 3 3 UU 9 3 3 uuu 33-941 TABLE XXII.— Continued, l 68 MATERIALS OF ENGINEERING— NON-FERROUS METALS. & bc«> £u . bca; °J*> 2 bCg S Ic&Sl be c f >2 4) w d> 'D 1 £ CO co’ be - c 1 >" > cti a 4 0 be a CO u 3 o m w bio (/o' Ajuoqjny W .W PQ o’.g 6 6-66 -6 66 • t> S> L .__.rn.rn. . cq cq . . _cqw .cam cq _w wu( 5 w c/ ^w c/ 2 'mw c/ ^ c, 3 'S ( jS c/ ^ l ^w t/ ^ c/ ^ 5 t/ ^cj c/ ^ t> £> LL LL LD £> D •oo: — J3A -jis ‘Ajpxxpop joj AjxAipnpuo^ •OOI = J3ATIS ‘jl?3q joj AjiAijo'npuo;} ’U 3 IFI\P Xjipqtsnj jo Jop-xo •(uosuqof pxxe JJ3AJB3 pire ssoupjBfj ’C^ll^W) AjX ■liqBOijBai jo aopaQ •(uojsjnqx) Xjqijonp OAijep^j VO vo ro N o' o' o o. o' o' , -crfm) Ajqrpnp jo JopjQ •qoux ojBnbs aod spunod Ajidbuox O o 0 O O' o o LT> LO O H c 2 £ o bc u >>3 4> o C 4> E.t: > & £ o o >> 4) rt be’E •XjtabjS oypsds H M o OO Tl-vo o o>no O H mw oi co ro n I 00 00 t-'.OO 00 o o h_ O' < OOOOCO Nl ’55 >>.23 OX! ui a- >> E §3 o-.^ c CJ aJ h o’ Ov vo 00 "55 >H "rt 4> a°|§ E o.SPk 0 72 »s , u ; o a lO vo 0* oo 'OVOVO'O'OVOVOVOVOVO'C' a a o s < 1.0 UU C G G NNN 3 3 3 UUU ;olde; BRASSES AND OTHER COPPER-ZINC ALLOYS. 169 oJa w g o "C •£ toxj Vi' m aj G O £3 « 5 ^ to d in b" V > Ih *£ V u >m S aJ I >. ■5 .ti »i o v. o u a PQ>dCQ 1 . .« > t> m .mm .mm mmmmm b & bb b bb bbbbb to m . 10 in co . O' 00 S : o' • 0 0 -0 0 • o o c a c OT3 O 0 o 0 t/i _Ei -• 3 13 3- o c o > w JS 3 o O 6> L ^ oj o3 V-rtv-V- bjc ^ bX) biO^ c/ii b(75 ro OCO vo h vo h O'* covo 00 W 00 10 t}-vO 0) ro h h o vo moo W 00 O On t^OO 00 O VO o 00 00 t^oo t>v ts. t^oo t^.00 00 Tt- m vo vo b& 2 to “a j= cn m %8 8 h NO b2 u to^ >>>y 1313 GG EE >» >»« 1 >n£ u to toy* JG a! C£ T3 ‘3 >. m b > Tt- On 8 8 o' o" 0 00 H On N 00' 0 00 O 0) VO C T/S U 2 b 1,1 to o b 13 13 m G G rt E E H £ to 3 J 2 Sn co 00 m ro h 00 o co moo Thvo com mcoOoo ^ on rh 00 (N NO tH P) CON H H o H 00 M co m m “WO w vo • t^vo c^vo vo mvo vo w w vo rC. tC _ _ _ _ VO vo vo vo vo VO vo oo_ o ^rooo 00 o’ ts N N N N N I m m m m imr^ovO w m t^s Q g 0 Q Q 000000 On On On On O O O 0 O vo m m vo m m m co co moo m m n rj* w o 0 o c> on r^vo vomwoOt^mwOOOOO J? S' C C C C C C NNN N x^ N x N x N x M x 333 33 33 33 UUU UU UU UU NJ C C NJM 3 3 3 U UU G G G G G G NNN NN N 3 3 3 3 3 3 UUU UU u C/5 s H 2 o K H b >S- id^o a =,- - ' ; Ng ^ s J*>d&3S 2 s ^ vo ^ m •Sw^«sa < jS fl - G. .^33 Issgc 5? S rb? cs<» « ^ s .V .. ■ 8 -‘Es . ji ® § K . r 10 8 to ^ s CO -s V.^J 3 to ■Vi^ C.JJ s o • S3 c ^ “ -vi ^ 1 ^ C S 8 ° « mb 41 170 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 when 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 ‘ c 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 BRA SSES A ND O THER COPPER-ZINC ALLOYS. 1 7 1 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, 25.52, and 33.94 per 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 metals. In this class also fall the “ KaU 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 Margraff, 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 “ 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. 1 73 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 IOO 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 l6 l6 “ “ “ close grained. 7 IOO 14 14 Yellow, slightly malleable. 8 IOO 12.5 12-5 “ more malleable. 9 IOO II II << a 66 10 IOO 10 10 Fine yellow, fine grain, malleable. 11 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 13 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 174 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 1 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 11, 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 1820-5, 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 90 10 4 90 10 3 * Holtzapffel. f 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 1 2 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. I76 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 KA L CHOI D S A ND MI SC ELL A NE 0 US ALLO YS. 17; 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 17S MATERIALS OF ENGINEERING— NON-FERROUS METALS. The ferro-manganese used to mix with gun metal con- tains from io 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, 1 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 lbs. 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. 1 DENSITY. I. II. ! WT. = 120^.568. WT. = I 20 gr . 275 , After casting 7-705 7.704 After tempering 7.706 7.704 After annealing 7.706 7-705 After tempering 7-707 7 707 After annealing 7-703 7.704 After impact 7-703 7.702 After tempering 7.701 7.702 After impact 7.699 7-703 * Ure’s Diet., Art. Aluminium. f Railway Review, Jan. 7, 1891. X 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. II. WT. — 12 ( 7 ) in which the Author found the constants for copper in tension to be A = 10,000,000; B = 100,000,000, and where — is the ratio of elongation to the length of the piece, and P, the load, is measured for tension, in pounds on the square inch of resisting section. For bronze of fair quality, the Author has, in some ex- periments, obtained : A = 12,000,000; B = 50,000,000. For brass, he obtained nearly : A = 12,000,000; B — 50,000,000. The coefficient A , above, is the modulus of elasticity. Reducing the above quantities to metric measure — kilo- grammes on the square centimetre — we have : A. B. For copper 703,000 7,030,000 For bronze 843,600 3,515,000 For brass 843,600 3,515.000 152. The Series of Elastic Limits. — If, at any moment, the stress producing distortion is relaxed, the piece recoils and continues this reversed distortion until, all load being taken off, the recoil ceases and the piece takes its “per- manent set.” This change is shown in the figure at f f " , the gradual reduction of load and coincident partial restora- tion of shape being represented by a succession of points forming the line f"f", each of which points has a position which is determined by the elastic resistance of the piece as 250 MATERIALS OF ENGINEERING— NON-FERROUS METALS. now altered by the strain to which it has been subjected. The distance O f" measures the permanent set, and the dis- tance f'f'" measures the recoil. The piece now has qualities which are quite different from those which distinguished it originally, and it may be re- garded as a new specimen and as quite a different metal. Its strain-diagram now has its origin at f", and the piece being once more strained, its behavior will be represented by the curve f'f' e VI f, a curve which often bears little resemblance to the original diagram 0,f, f\ The new diagram shows an elastic limit at e*, and very much higher than the original limit e lw . Had this experiment been performed at any other point along the line/' f, the same result would have followed. It thus becomes evident that the strain-diagram is a curve of elastic limits, each point being at once representative of the resistance of the piece in a certain condition of distortion, and of its elastic limit as then strained. The ductile, non-ferrous metals, and iron and steel, and the truly elastic substances, have this in common — that the effect of strain is to produce a change in the mode of resist- ance to stress, which results, in the latter, in the production of a new and elevated elastic limit, and in the former in the introduction of such a limit where none was observable be- fore. It becomes necessary to distinguish these elastic limits in describing the behavior of strained metals, and, as will be seen subsequently, the elastic limits here described are, under some conditions, altered by strain, and we thus have another form of elastic limit to be defined by a special term. In this work the original elastic limit of the piece in its ordinary state, as at e, e\ e" , etc., will be called either the Original , or the Primitive , Elastic Limit , and the elastic limit corresponding to any point in the strain-diagram produced by gradual, unintermitted strain, will be called the Normal Elastic Limit for the given strain. It is seen that the dia- gram representing this kind of strain is a Carve of Normal Elastic Limits. The elastic limit is often said to be that point at which STRENGTH OF NON-FERROUS METALS. 251 a permanent set takes place. As will be seen on studying actual strain-diagrams to be hereafter given, and which exhibit accurately the behavior of the metal under stress, there is no such point. The elastic limit referred to ordina- rily, when the term is used, is that point within which recoil, on removal of load, is approximately equal to the elongation attained and beyond which set becomes nearly equal to total elongation. It is seen that, within the elastic limit, sets and elongations are similarly proportional to the loads, that the same is true on any elastic line, and that loads and elongations are nearly proportional everywhere beyond the elastic limit, within a moderate range, although the total distortion then bears a far higher ratio to the load, while the sets become nearly equal to the total elongations. 153. Effect of Shock or Impact ; Resilience.— The be- havior of metals, under moving, or “live,” load and under shock, is not the same as when gradually and steadily strained by a slowly applied or static stress. In the latter case, the metal undergoes the changes illustrated by the strain diagrams, until a point is reached at which equilibrium occurs between the applied load and resisting forces, and the body rests indefinitely, as under a permanent load, without other change occurring than such settlement of parts as will bring the whole structural resistance into play. When a freely moving body strikes upon the resisting piece, on the other hand, it only comes to rest when all its kinetic energy is taken up by the resisting piece ; there is then an equality of vis viva expended and work done, which is expressed thus : WV* Tw ~2g~ ~ J pdx=p m s\ in which expression W is the weight of the striking body, V its velocity, p the resisting force at any instant, p m the mean resistance up to the point at which equilibrium occurs, and s is the distance through which resistance is met. 252 MATERIALS OF ENGINEERING— NON-FERROUS METALS. As has been seen, the resistance may usually be taken as varying approximately with the ordinates of a parabola, the abscissas representing extensions. The mean resistance is, therefore, nearly two-thirds the maximum, and WV 2 2g p dx = p m s = et — ae 2 , nearly • • ( 8 ) where e is the extension, and t the maximum resistance at that extension, and a a constant. Brittle materials, like hard bronzes and brasses, have a straight line for their strain- diagrams, and the coefficient becomes y 2 instead of 2 /^ and WV 2 zg — ae 2 = V> et = V ( 9 ) 154, Resilience, or Spring, is the work of resistance up to the elastic limit. This will be called Elastic Resilience. The modulus of elasticity being known, the Modulus of Elastic Resilience is obtained by dividing half the square of the maximum elastic resistance by the modulus of elasticity, E y as above, and the work done to the “primitive elastic limit ” is obtained by multiplying this modulus of resilience by the volume of the bar.* * The total area of the diagram, measuring the total work done up to rupture, will be called a measure of Total ox Ultu mate Resilience. Mallett’s Coefficient of Total Resilience is the half product of maximum resistance into total extension. It is correct for brittle substances and all cases in which the primitive elastic limit is found at the point of rupture. With tough materials, the coefficient is more nearly two-thirds — and may be even greater where the metal is very ductile, as, e.g.y pure copper, tin, or lead. Unity of length and of section f R * Rankine and some other writers take this modulus as—, instead of — E E * STRENGTH OF NON-FERROUS METALS ’ 253 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 v 'f'f ", 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 MA te rials of engineering— non-ferrous metals. point is at one-half the maximum resistance, or elongation, attained. Thus we have <■»> but p varies as 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 f'f", 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; and W—P . . . (11) 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 s [ s a p dx—a \ x dx — —s 2 = o Jo 2 Ws s — 2 W a ( 12 ) For a static load, if / is the elongation, W=P= as' Hence, (13) 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, i.e ., 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 ynass 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 knowledge 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 256 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 “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. 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- 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 Fig. 4. 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 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- R R ance — y per unit of area, and — y dy dx on the area dy dx ; dx d. while the moment of resistance, Tf, 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 x , R being the “ Modulus of Rupture ” : R b d 1 . o 'dx y 2 dy dx — M, J o i.e. y 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 'dx y dy dx — M\ o 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 tlie Theory of Resistance. *6o 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 1 = i Rbd 2 ; b being the breadth, and d — 2 d z 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 j y 2 dy dx divided by the depth d x to the neutral line, or as, shown by M. Navier, to the axis through the centre of gravity. The quantity j 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, M= —Pl= \Rbd * ; 4 6 and R = zbd* STRENGTH OF NON-FERROUS METALS. 261 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 : (1.) Beam fixed at one end, load at the other: PI =~ Rbd 2 ; P=\R b -T- o 0 / (2.) Same, with load distributed uniformly: — Wl ~ M; 2 (3.) Beam supported at ends, loaded at middle: - Pl=M ; 4 ( 4 -) Same, uniformly loaded: (5) Beam firmly fixed at ends, loaded at middle: Same determined by Barlow’s experiments: lpi=M; (6.) Same uniformly loaded : — Wl = M; W=2R b AL. 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, is taken into account. When the dimensions all become unity, we have, neglecting W, 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 18 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. \Pl = M ; STRENGTH OF NON-FERROUS METALS. 263 c c E- 6 ?,°' D 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 EE be 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 x from the neutral axis, be = A will be its elonga- tion, and if the radius of curvature, OR , is called p, we have P and the stress on any fibre of the area, a — dy dz , since — A : dx, will be a Fig. 6. and the moment about the intersection with the neutral line is E py — — y 2 dy dz, accordingly as the fibre is above or below that line. The total moment will be F rb rdi f di M — — y 2 dy dz -j y 2 dy dz, PJoJo PJ0J0 For cases in which the section is symmetrical about the neutral line El E b >J rJ4d 264 MATERIALS OF ENGINEERING— NON-FERROUS METALS. in which integrals b is the breadth of section, d 1 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 dx 2 which value reduces the equation for M — PI, as in Fig. 6, to PI = M ^ EI dx 2 ' dv 2 when may, as is probably usually the case, be neg- CIPC 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 : V -*) p =EI% which, being integrated once, gives S = iZ?( 2& -‘> + c where x — O, dy dx — O, and C O. Again integrating, and y = 6^7 - * y ) + C , 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-lUl V ~ lEI' as already given. For uniform loading, and d 2 y dx 2 w 2 ~EI D — wl 4 _ Ml' etc. 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, n-l p T- p-lEEL 3 £1’ 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, D -UEL. w- s EN. 8 El ’ l* For beams supported at the ends, these equations fof single and distributed loads are i PI 3 &DEI 48 El' l 3 ; ^ 1 W/ 3 , T/r7 7SDEI D = T$ £ 7 ’ nearly; W= J ~F-' For beams fixed at the ends, we have D 1 PI 3 , n 200 DEI — t > nearly ; P = t- — < 200 El / 3 1 F7 3 , TT7 400 DEI D = > nearly; fF = - — 400 £/ ' / 3 For rectangular beams, / — Jg- bd 3 , and we may write the simplified formula for a beam sup« ported at the ends and loaded in the middle, D aPl 3 bd 3 For a beam fixed at one end and loaded at the other, \ 6 aPl 3 D = bd „ and, when uniformly loaded, the t o cases give and D = D = 5 aWl 3 8 bd 3 ’ 6 aWl 3 bd 3 STRENGTH OF NON-FERROUS METALS. 267 Where the length is measured in inches, a = -i= » and when in feet, a — I "^ -« 4E 4 E 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: F/=M=—\ ri f*dr. T' 1 J ro For solid cylinders, Fl—M= \.$jo%sr? = o .2sd\ For hollow cylinders, fr 4 _ r 4 \ d* — d 4 Fl=M = 1.5708J ° J =0 -2s d 0 ; 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 Q and r 1 are the radii of the shaft, internal and external, and d Q and d i 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 32 M x Fix a ~c^~~^d*’c~ l0 ' 2 ~ciy x being the length of the part twisted ; fi=m= ac ooqSC Fa 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 ¥ ring, 2 nr dr, for the stress upon it s = — and for its lever- ^ i arm, r. Then Fl = M = — 1 [’ "V dr = - — 1 (r* - r*) = I n A (d* - d«) r l ) r o 2 r x oy 16 d x y 0/ for hollow shafts, and when r Q — O, d 0 = O, as for solid shafts, Fl — M= 1.5708 s l r , 3 = 0.196 s x d\ To obtain the diameter, we have : For solid shafts, For hollow shafts, 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 — 2nr dr, its lever-arm r , and the value of ^ becomes constant and equal to s x . Then FI — 2ns 1 r 2 dr — — Tts 1 ( r ? J ro 3 r o) — 0.26s , (4 - d 0 ). and when r Q = O, FI — o.26s x d? — 2.2s l r l \ 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 x r 2 as the radii of the two parts, the total resistance would be Fl=M= ? Sl r* + j s,(rj> - r?) = 0.528.?, (4^ - r , 3 ). * 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. 270 MATERIALS OF ENGINEERING— NON-FERROUS METALS. If a e and a r are the angles of torsion at the elastic limit o f the piece and at the beginning of rupture or of flow, If a e — a r , M ~ as already shown for brittle sub- stances. When a e = o, as in absolutely inelastic materials, did such exist, or when a r — 00 , as with perfectly ductile sub- stances, M= 1 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. Wrought iron. Copper Tin VALUES OF K. 1,700 380 220 Gun bronze Brass Lead 460 425 170 167, 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 kg s * 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. Copper, forged 34.000 19.000 25.000 38.000 45.000 48.000 50.000 2,390 1,336 1,753 2,671 3,164 3,374 3 , 5 i 5 “ east “ forged. FI = 1.6 q r*. STRENGTH OF NON-FERROUS METALS . 285 The values of T and C are not, however, the same, and the differential expression must be integrated for the two sides of the bar separately. Cast copper , tested by transverse stress, when of fair quality should give figures equal to, or exceeding, those obtained in the record which follows : TABLE XLII. TEST OF BAR OF CAST COPPER. No. 55. — Material : Copper, cast in iron mould. — Dimensions : Length between supports, l — 22"; breadth, b = 0.985''; depth, d = 0.970." 20 40 80 100 5 140 180 200 5 240 280 320 360 400 5 440 DEFLECTION. SET. MOD. ELASTICITY. O.OO33 O.OO75 0.0176 0.0224 O.OOOI i 0.0095 1 5^792 ,947 13,459,739 13,219,331 O.0337 O.0477 O.0552 12,301,425 11,174,068 10,728,725 O.0674 0.09x0 O. 1176 0.1553 O.2057 10,540,763 9,111,146 0.1114 0.2883 480 500 5 540 580 Ruptured 580 680 720 800 840 860 0.4088 0.4855 0.6343 0.8378 0.8653 1.46 1- 74 2- 39 2.85 3.23 Supports slid out. Bar bent. Breaking load, P = 860 pounds. 9 P l Modulus of rupture, R= Tbd 2 *=30,621 619 The modulus of rupture for good cast copper should thus exceed 30,000 pounds per square inch (2,109 kilogs. per sq. cm.), but may be expected to vary between 20,000 and 40,000 (1,406 and 2,812 kilogs.) with variations in the sound- ness and quality of the metal. Rolled Copper , as tested by the Author, when of good quality and sound, may give values of the modulus of rupt- ure as high as R = 60,000 pounds per square inch (4,218 kilogs. per sq. cm.), and sometimes exceeds this figure, one test under the eye of the Author, having given R = 60,900 R m = 4,281. 286 MATERIALS OF ENGINEERING— NON-FERROUS METALS 174. The Modulus of Elasticity of Copper is almost in* variably obtained by calculation from the results of transverse tests, using the expressions, F - P/S F- PP 11 ” 4 ssr 4 sbd*' for the general case and for rectangular sections, respec* tively,* when the weight of the bar may be neglected, as is the case with metal test-pieces, usually. By reference to the records of tests of cast copper already described (Table XXXVL, Art. 168), it will be seen that this modulus may vary, with even the variation of light loads, from 10 to 15 million pounds per square inch (703,000 to 1,054,500 kilogs. per sq. cm.), and the same differences are observable as a con- sequence of varying quality. The higher values obtained in any one test are the most probably correct, and it may be assumed that the modulus of elasticity of copper approaches 15,000,000 pounds per square inch (1,054,500 kilogs. per sq. cm.), as the metal is obtained in a state approximating purity and soundness. Usual values are two-thirds to three-fourths these. Some authorities give values exceeding the maximum, as above, by 20 per cent., but such figures are not to be expected in the ordinary work of the engineer. Forged and wire-drawn copper, as tested by Wertheim, gave the following values of this modulus: KILOGS. PER SQ. CM. Copper, hard-drawn 1,245,000 “ “ 1,254,000 " annealed 1,052,000 “ “ 1,254,000 or very nearly 18,000,000 pounds per square inch for hard- drawn, and 20 per cent, less, in some cases, for annealed wire. * See Part II., p. 499, § 268. STRENGTH OF NON-FERROUS METALS. 2 8 ; 175* Copper Subjected to Torsion is found to exhibit the same variation of resistance with quality and physical structure that has been seen in other methods of test. The experiments of the Author give values of s x in the equations for total resistance, Art. 1 66, ranging between 20,000 and 40,000 pounds per square inch (1,406 and 2,812 kilogs. per sq. cm.), the lower figure for cast copper of ordinary soundness, and the higher for good forged or rolled copper. Thus for the two cases, it may be assumed that copper shafts will break under load when accordingly as they are made of cast or worked copper, when the units employed are inches and pounds, or when the units are metric. Copper is seldom subjected, however, to any other than tensile stresses. It would probably be more correct to use the expressions in Art. 166 for tough metals than the above, making the true value of s x = 15,000 to 30,000 pounds. 176 . Results of all Tests of Cast Copper made for the Committee on Alloys of the U. S. Board being collected, re- jecting all tests of samples known to be defective, the follow- ing figures were obtained. It will be remembered that these experiments were made with ordinary commercial metals melted and cast in the usual way and purposely without other precaution than is usually taken in every-day foundry work. Much higher figures, as has been seen, may be at- tained. 288 MATERIALS OF ENGINEERING— NON-FERROUS METALS TABLE XLIII. AVERAGE OF TESTS OF COPPER. TRANSVERSE TESTS. TENSILE TESTS. TORSIONAL TESTS. , , 0 CM O 'Si Tenacity per 0 O a O d C/3 'C 0 square inch of— 75 c 13 75 £ U'O >» ctf 4-* u -6 li M cd O •a aS 0 tuo as 3 a e *0 limit — pa jreaking loi 0 C/5 Jt O on — parts nal length d .0 0 u C/5 d 0 t> V •o a 1 1 •£‘5 C as ;5
  • reaking lo< 'C 5 0) 0 C a 15 Js O Js "3 aS tuo 73 C 0 Vh 3 O 3 g c 0 0 0 '53 c aS 5 1 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. S. G. X A. W. RESISTANCE TO RUPTURE PER MILLIMETRE. Coefficient of elasticity (Tredgold). Rapidity of sound | (Chladni). ] By extension (Guyt-Mor- veau). By compres- sion (Ren- nie). Lead n -352 12.94498 O.8769 0.022 i -45 600 Tin 7.285 7-35294 O.9907 0.063 6.20 3.200 7-5 Gold 19.258 12.43013 1 • 5493 0.274 .... Silver 1 10.542 6.75803 1-5599 0.341 9.0 Zinc 6.861 4.03226 1-7015 0.199 9.600 Platinum ! 21 • 530 12.33499 1.7454 0.499 Copper 8 850 3-95695 2.2365 0.550 38.55 12.0 Iron. i 7.788 3 • 39205 2.2959 1. 000 20 . 000 17.0 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 STRENGTH OF NON-FERROUS METALS. 301 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, 302 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. 7th. 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 oe desired can be produced. 9th. 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. 10th. 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. 303 TABLE L. MODULI OF ELASTICITY OF METALS. LBS. PER KILOGS. PER SQ. IN. SQ. CM. Lead 2,500,000 7,700,000 11,500,000 10,000,000 17.000. 000 24.000. 000 176,000 492,000 808.5OO 703,000 Cadmium Gold Sdver Palladium 1,195,000 1,687,000 Platinum 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 0.00001 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 6734 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 : (i.) ZINC. — NUMBER OF BENDINGS OF CHEMICALLY PURE ZINC — IOO. 1 • 100 parts chemically ’3 £ B £ B p pure zinc alloyed c i_ c 0 'B with B T 3 i . S * Tin, a U rt 893 Wrought iron 480 50,000 15.000 Al. sheet 165 26,000 23.000 cold rolled 168 55,000 39- 6i 5 cast 160 15,000 13.321 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. * four. Franklin Inst., Feb., 1891 ; May, 1892. < 4 *. 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, 1; to copper, 11, tin, 1; 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. 307 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, 1. Small bars made of gun metal gave higher figures. One set of 1 6 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 kilogs. 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. S 29,000 2,039 “ 9 T *7 ; “ 8.3 31,000 2 ,Il 6 “ 91 ; “ 9 33,000 2,130 “ 90 ; “ 10 38,000 2,165 189. 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 . . 30,000 2,530 “ 82.81 ; “ 17.19 34,000 2,390 " 81.10; “ 18.90 40,000 2,812 “ 78.97; “ 21.03 31,000 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 ; LBS. COMPRESSION, INCH. LOAD ; LBS. COMPRESSION, INCH. 30,000 O . 6460 36,000 O.79I4 32,000 O . 6904 38,000 O.8115 34,000 O.73H Resistance, max. 123,860 lbs. 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. 10,000 0 . 0609 25,000 O.5O92 15,000 O. 2110 28,000 O . 8062 20,000 o -3599 23 , 5 0 0 Max. resistance, 92,894 lbs. 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, Mallet RESISTANCE OF BRONZE GUN-METAL TO COMPRESSION. 310 MATERIALS OF ENGINEERING— NON-FERROUS METALS THE PRESSURE IS IN LBS. AND THE COMPRESSION IN DECIMALS OF AN INCH. ! « 8 Jq in ** & O NO - H -NO VO h . 0 • n m m io> . . . ... . io'o • vo . u-> m 10 iTi 8 x> 5 J % co cnO-'O • 10 h 00 O' CO N • VO • O' N 0 - 1 - • • ... . 10 ) 1 /) • IT) .-*- 10 ) 10 to 8 •O »o * S m . . O O • m .00 1 n m . . cn '«*• • co • vo on • • ... . into • in . rj- tj- c /5 Q .D 0 nn • ... . 0 Q • m . 0 0 co mm. m ... . on 0 on • n m co ^vo • m ... . m • Tt- w 8 XI tJ N W N W N O ... • OOOi'O - 0)00 fO 00 00 H VO ... . UI'O 00 VO • 0 O' (O)io>-t- ... . -*--*-■>*- -f • ro -r m i § i -4 0 w ... . m 0 0 r- • co in vo -*-vo N ... . O N d) H . TfvO 10 ) ro m ro -*• ... • • ro ro ro CO 8 X) *0 ij 5 - O O .10). io) ovOO vo • « 10) 00 0 S ro f-» .H. H I 0 )f-r^vo . O' N 0 co -T ro to -to- co cococo co -nco co to O X) 0 h 4 JD 11) K O M .00 O 00 N 0 co O 000 O' VO 10)00 0 • >OVO -*■ 0 N 1-1 H 10)00 vo N CO N CO -NN N rococo CO NNN N . O CO O ? i 10 i -3 « w w 00 000 hn w 0 on 0 conn on m 0 m n msm vo woo O WWW W WWW 1 WWW W WWW N . 0 j§ 0 t -3 0" H H 00 0 VO Q H 0 cn 0 w W M t^wON a* vo co ^ ^o Oho 0 m on M (N H H MHM M WWW W HHM M to O x> & m rj- 000 vo O m m n omen cn w in cn cn 0 g*cg eg cn^-m cn 0 O' h 3 § HH 10 C -.00 H 10 ) 10 ) N H O' ONO -t- 10 ) 000 t-. 10 t^vo VO CO N to N vo f^'O VO N N 10) CO 000 0 000 0 000 0 000 0 c /5 Q 3 % 10) w co 10) 00 10 )CO O' 10) to) w N CO N 0 MQH 0 O H H O OOO O 000 N 000 0 000 0 000 0 1 SPECIFIC GRAVITY. 't n ci m m cn n m h vo 0 00 ens vo on m m on h Tt*vo nm cn 0 vo 0 n in h on 00 on 00 vo oi m m m on w 0 t ^0 on cnojw w vo cn cn rt- o'O'h 0 t^vo vo 000000 00 000000 00 t>s t^oo 00 00 00 00 00 SPECIMEN. (A No. 1. 4 B (c - Mean No. 2. \ B (c Mean No ' 3 ' Mean No ' 4 ’ 1 ®::::::::::::::::::: Mean STRENGTH OF BRONZES. 311 These experiments were made by Col. Wilmot, R.A., at Woolwich Arsenal, at the request of Mallet, in 1856. Nos. 1, 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 1 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 — ^mm i mm . Copper 19 23 27 33 40 Did no ( with 70 b 7 8 to 9 10 14 15 t succeed lows. Bronze of 97 parts copper Bronze of 96 parts copper Bronze of 95 parts copper Bronze of 94 parts copper Bronze of 90 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, 1 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 pef 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 — (. Kirkaldy ). PULLING STRESS PER SQUARE INCH. ULTIMATE EXTENSION IN PER CT. NUMBER OF TURNS IN 5 INCHES. Hard. Annealed. Annealed. Hard. Annealed. Copper 63,122 lbs. 37,002 lbs. 34-1 86.7 96 Brass 81,156 “ 5L550 “ 36.5 I4.7 57 Charcoal iron 65.834 “ 46,160 “ 28 48 87 Coke iron 64,321 “ 61,294 “ 17 26 44 Steel. 120,976 “ 74,637 “ 10.9 t 79 Phosphor-bronze No. 1 . |I59 515 “ 58,853 “ 46.6 13-3 66 do do No. 2. 151,119 “ 64,569 “ 42.8 15.8 60 do do No. 3. I 39 H 4 I “ 54 ,m “ 44.9 17-3 53 do do No. 4. 120,950 “ 53,381 “ 42.4 13 124 Elastic stress per square inch. Ultimate stress per square inch. Ultimate permanent extension in per cent. lbs. lbs. per cent. Phosphor-bronze No. 1 . . . 55,200 73,987 3.2 do do No. 2. . . 40,500 63,653 9.4 do do No. 3. . . 26,300 54,o6o 31*3 * Journal Franklin Institute, 1879. f Of the 8 pieces of Steel tested, 3 stood from 40 to 45 turns and 5 “ “ H “ 4 “ STRENGTH OF BRONZES. 313 TENACITY OF PHOSPHOR-BRONZE — ( Uchatius ). Specimens. Absolute resistance in kilogs. per square centimetre. Elastic resistance 1 in kilogs. per square centimetre. Stretch in per cent. kilogs. kilogs. per ct. Phosphor-bronze No. o. 3,600 600 20.66 do do No. 00. 5,660 3.800 1.60 Krupp Cast Steel 5,000 1 .000 1 1. 00 TENACITY OF PHOSPHOR-BRONZE ( Wohler). Tests by Repeated Application of Direct Strain . PHOSPHOR-BRONZE. ORDINARY GUN METAL. Tensile stress Number of efforts No. Tensile stress j Number of efforts per square in. until rupture. per square in. until rupture. I 10 Tons. 408,350 I 10 Tons. j Broke before total | stress was applied. 2 12* “ i 47 ; 850 2 10 “ 4,200 3 7* “ 3,100,000 3 7* “ 6,300 Tests by Repeated Bending in the same Direction. PHOSPHOR-BRONZE. ORDINARY GUN METAL. No. Tensile stress Number of bends No. | Tensile stress Number of bends per square in. until rupture. per square in. until rupture. 1 10 Tons. 862,980 1 10 Tons. 102,650 2 9 “ 4 Million ) _ c 2 9 “ 150,000 3 4 7* “ 6 “ -3 “ (. oju 2 “ ) 8 ' .a 3 7* “ 837,760 A bar of hammered phosphor-bronze, under 12 tons per square inch, without breaking, stood more than 23^ million turns, whilst according to Wohler’s experiments, a bar of Krupp cast steel under 12 tons, broke after 879,700 turns, and another bar of the same under 13 tons, broke after 1,007,550 turns. 3 H 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 ; Kiinzel’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. * Polytech. Centralblatt , Jan., 1874. WEAR OF BEARINGS. — KUNZEL. STRENGTH OF BRONZES. 315 Qj rt _Q tp ID p a o P X o M in O CX— « V O or P co O- 00 01 Cost metal 1 ,000 k mpfr < O G ill 4-1 ,0 u G cu CO cj O CO CJ CO 0 co. 6 6 0 0 CO 6 ar per d kilo— etres u V 2 cx O G 14 ■* *£ C/3 ^ a & 0 O -+ 0 VO 0 0 0 p O CO CO -r CO 0 M CO P H l 001 J3d •soL }B U32fBj’ |BJ3UI JO ssoj pue sasuadxa Sui -jpm aqj ‘sajjaiDoqsj 001 jad sSuuBaq jo JS03 0 c 12 .2^ .t: o a g.3 8 1 .S u o p >> a co r ^ CO JO u O 0 c P.5 pp O G O o o p (/2 o P See Railroad and Engineering Journal , paper by Dr. Dudley. 1591-92, for valuable details o f similar work. 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 ^gth to |th 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. 1 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 3,48o 5-5 Ditto. 4,769 13.2 2,079 28.8 4,535 35-3 Ditto and forged. 4,77° 16.8 2,645 23.6 3,7i7 3-8 Cast in metal mould, slight flaw ’O in specimen. c g 4,77* 12.0 1,890 30.3 4,772 25.7 Cast in metal mould and forged. . 3 1 ROLLED RODS. rt QQ 6,536 11 .0 1,732 29.0 4,567 44.6 Mild, for ships’ bolts and rivets. 1 6,545 16.6 2,615 3°-7 4,835 20.7 High, for Engineers’ bolts, pump rods, etc. 6,546 14.6 2,299 30.0 4,725 26.2 Medium. 1 6,547 34-4 5,4*7 39-6 6,237 11 .6 Cold rolled. AREA OF SPECIMENS, O. I33 INCH. LENGTH OF BREAKING PART, 2 INCHES. . f 7,364 13.8 2,173 28.57 4,504 28.7 Pulled in direction of fibre. u 7,365 14.06 2,205 28.46 4,488 23.2 Across fibre. rt 1 7,369 14.06 2,205 30.13 4,740 47.8 With fibre. E 7,372 14.8 2,331 30.78 4,850 34 - 1 Across fibre. l 7,374 16.7 2,630 30.1 4,740 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, 1 in. (2.54 cm.) square.] LOAD AT MIDDLE OF BAR. Elastic Limit. At Rupture. Lbs. Kgs. Lbs. Kgs. Manganese Bronze 2,688 122 6,048 275 Gun (Copper-tin) Bronze 1,232 56 2 , 9 12 132 195. Manganese Bronze tested by Impact, resisted the blow as shown in the following table, furnished the Author by the inventor : MANGANESE BRONZE BARS. IMPACT. 318 MA TE RIALS OF ENGINEERING— NON-FERROUS METALS. STRENGTH OF BRONZES. 319 The wrought iron was of three grades ; the gun-metal was partly (Nos. 1, 2, 3), of usual good quality, and partly (Nos. 4, 5) specially made for the test of copper, 16, tin, 2, and copper, 1 6, 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. P. ct. Iron. Area, sq. mm. I 8 co I ,000 1,100 1,200 I 1,300 1,400 Cn O O 1,600 1,700 Copper of commerce, melted. . Copper of commerce, rolled. . . Pure copper, melted. ... 94 95 hi 98 92 92 97 97 81 r 0 o -5 1.25 2-5 0.25 0.25 1 0.5 3 -o 5 -o 0.25 0.25 3 0.5 4-5 ($) 0.25 0.25 5 0.5 5-5 (+) o -5 6.0 °-5 o -5 o .5 o -5 Pure copper, melted Copper and iron, melted Copper and iron, melted Copper and iron, melted Copper and iron, melted 2 2 4-5 4-5 0.25 0.25 0 75 0.50 i.S 2.0 2.5 3 .o (§) 3.5 3-5 Pure copper, rolled Pure copper, rolled 89 ' 88 90 Copper and iron, rolled 4-5 4-5 Copper and iron, rolled NAME OF METALS. I P. ct. I Iron. 1 1,800 1,900 2,000 2,100 2,200 2,300 2, 400J2, 500)2,600 2,700 2,800 I Copper of commerce, 2 Copper of commerce, 0 e 1.5 2 . K 4.5 5.5 O Pure copper, melted °*5 O A 1 Pure copper, melted ..... 4 C| Copper and iron, melted. Copper and iron, melted. Copper and iron, melted. Copper and iron, melted. Pur^ copper roll pH 2 6 c e n O 8 t; 10. 0 12.5 15.0 A c: 4-5 0 • 5 7 (II) A O 7 8 Q 4 O 4-5 0.25 0. ^ 0.25 O 6>C * 0 2.0 8.75 0.25 12.0 1.0 1.20 1.75 2.5 4.0 IO i Pure copper, rolled .... 1.5 3.0 4.5 8.0 16.00 11 12 Copper and iron, rolled . . Copper and iron, rolled .. 4.5 A m C O • 4*0 * {Ann. de Chim. et de Phys 4 serie, t. xxx., Nov., 1873, 26.) f The test was arrested because a blowhole was formed in the sample. % The broken section presents blowholes. § At 1,600 kilogrammes one lug of the piece was broken. jj The sample broke without the two pieces being entirely separated 320 MATERIALS OF ENGINEERING— NON-FERROUS METALS. NAME OF METALS. Per ct. 2,900 3,000 3, 100 3,200 3,300 3,400 3,500 3,6-0 Breaking load. Strength per sq. mm. Density. j Copper of commerce, melted Kilog. Kilog. Copper of commerce, rolled 2,300 I , 3 °° 1,000 24.210 n.711 10.204 Pure copper, melted .... 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 2,400 26.086 2,800 2,300 2,300 3,500 3,600 28.865 28 . 220 25.842 . 39-772 40.000 8.879 8.904 Pure copper, rolled Copper and iron, rolled. Copper and iron, rolled . 4-5 4 1 0.25 o -5 o .5 1.0 0.25 2.5 0.75 2.5 1.5 4-75 3-5 9.0 8.891 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 1,800 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, 1. 1 ; 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 STRENGTH OF BRONZES. 321 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, 46th 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 $22 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 1 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.OI 3 None. Metallic zinc None. Metallic silver 0.014 None. Metallic arsenic . None. Metallic antimony None. None. Metallic cobalt Metallic bismuth None. None. Metallic nickel. . Metallic lead Trace. None. Metallic manganese Metallic molybdenum None. Metallic tungsten . Metallic copper 99.420 None. None. Metallic tin 99.978 Suboxide of copper 0-537 0.041 Carbon Matter insoluble in aqua, rerna 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. 1 Cu. Sn. T I 0 100 O 8.487 2 . 96 1 98.1 1.9 97.89 1.90 (J . 8.564 3 48 1 96.27 3-73 j 96.06 3-76 8.649 4 24 1 92.80 7 20 j 92.11 7.80 8.694 5 90.00 10.00 90.27 9-58 8.669 6 12 I 86.57 13-43 87.15 12.73 8.681 7 . . 80.00 20.00 80.95 18.84 8.740 8 6 I 76.32 23.68 7664 23.24 8.565 9 . . . . 70.00 30.00 69.84 29.89 8.932 10 4 1 68.25 31-75 68.58 31.26 8.938 11 65.00 35 -oo 65.34 34-47 8.947 12 3 I 61.71 38.29 j 62.31 37-35 8.970 13 12 5 56.32 43-68 56.70 4317 ! 8.682 14 2 1 51.80 48.20 51.62 48.09 8.560 15 12 7 47-95 52.05 47.61 52-14 8.442 16 3 2 44-63 55-37 44.52 55-28 8.312 17 4 3 41-74 58 . 26 42.38 57-30 8.302 18 6 5 39.20 60.80 3-37 61.52 8.182 19 1 1 34-95 65-05 54.22 65.80 8.013 20 3 4 28.72 71 . 28 25.85 73.80 7.948 21 3 5 24.38 75-62 23.35 76.29 7-835 22 1 2 21 . 18 78.82 20.25 79 63 7.770 23 1 3 15-19 84.81 15.08 84.62 7-657 24 1 4 11.84 1 88.16 11.49 88. 47 7.552 2 ^ 1 5 9.70 90.30 8-57 91-39 7-487 26 1 12 4.29 95-71 3-72 96.31 j 7.360 27 1 48 1. 11 98.89 0.74 99 02 ! 7-305 28 I 96 0-557 99-443 0.32 99.46 7.299 20 0 1 0 100 7-293 *7 * 324 MATERIALS OF ENGINEERING— N OX-FERROUS METALS. SECOND SERIES. NUMBER. COMPOSITION OF ORIGINAL MIXTURE. MEAN COMPOSITION BY ANALYSIS. MEAN SPECIFIC GRAVITY. Copper. Tin. Copper. Tin. qi Q 7 . ^ 2 • 5 99.09 0.87 32 92.5 7-5 94.10 5-43 8.684 33 87.5 12.5 88.40 n -59 8.647 34 82.5 17-5 82.72 17-33 8.792 35 77-5 22.5 77.56 22.25 8.917 36 * 72.5 27-5 72. 89 26.85 8.925 37 67-5 32.5 67.87 32.09 8.907 38 62.5 37-5 62.42 37.48 8.956 39 57-5 42.5 57.87 42.05 8 . 781 40 52.5 47-5 53.46 46 54 8.643 4 i 47-5 52.5 47.27 52.72 8-445 42 42.5 57-5 43-99 55-91 8-437 43 37-5 62.5 37-10 62.90 8. 101 44 325 67-5 30.76 69.19 7-931 45 27-5 72.5 26.62 73 -i 8 7 - 9 T 5 46 22.5 77-5 22.10 77-58 7-774 47 17-5 82.5 16.70 83-23 7.690 48 12.5 87-5 11.68 88.25 7-542 49 7-5 92 5 6.05 93-77 7.419 50 - 2-5 97-5 2 . 11 97.68 7-343 200. 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. 325 TABLE LXI. ESTIMATED TEMPERATURES OF CASTING. COMPOSITION BY ORIGINAL MIX- TURES. os w H < £ < h W S b TEMPERATURES OF WATER, CENTI- GRADE SCALE. SPECIFIC :at. CALCULATED RELA- TIVE TEMPERA- TURE. Copper. Tin. H x 0 3 £ h X 0 3 £ Initial. Final. ASSUMED HE Centi- grade. Fahren- heit. 3 1 ' 97.5 2.5 Gram . 907 Gram . 74 J 22.8 i 4-5 0.09417 7 1909.9 3469-8 3 2 * 92.5 , 7-5 907 IOI 12.8 3 1-7 18.9 0.092231 1871.9 3401.4 33 87-5 12. 5 907 149 16.7 42.8 26.1 0.090285 1802.6 3276.6 34 82.5 17-5 907 362 9-4 I 60.0 5 ° .6 0.088339 1495 -i 2723.0 35 77 5 22.5 9°7 225 15.0 47-3 32-3 0.086393 1554-5 2829.2 36 72.5 27 -5 9°7 157 11. 7 33-3 2I;6 0.084447 1511.8 2751.8 37 67-5 32.5 9°7 97 11 . 1 26.1 i 5 -o 0.082501 1726.2 3148.8 38 62.5 37 5 9°7 a 77 10.6 3 i -7 21. 1 0.080555 I 373-9 2503-4 39 57-5 42.5 9°7 129 17.2 32.8 15.6 0.078609 1428.0 2602 . 4 4 ° 52.5 47-5 9°7 214 8-3 35 -o I 26.7 0.076663 i 5 «.i 2751.8 4 i 47-5 52.5 9 °7 216 12.2 50.5 38.3 0.074717 2205.0 4001.0 42 42.5 57-5 9°7 328 9-5 47.2 37-8 0.072771 1063.8 1945.4 43 37-5 62.5 907 293 i 3-9 38.9 25.0 0.070825 ii 3 i -7 | 2067 . 8 44 32.5 67-5 907 255 8.9 32.2 23-3 0.068879 j 756.9 3192.8 45 27-5 72-5 907 85 7-8 18.3 10.5 0.066933 1701.6 3093-8 46 22.5 77-5 907 277 12.2 389 26.7 0.064987 1382.7 2519.6 47 17-5 82. 5 9°7 241 i 5.5 37-2 21.7 0.063041 U 33 I -i 2427.8 48 12.5 87.5 907 104 14.4 22.7 8-3 0.06:095 1211.9 2211.8 49 7-5 i 92-5 9°7 240 18.9 33-3 14.4 0.059149 956.5 1752.8 5° 2.5 97-5 9°7 154 20.5 27.2 6.7 0.057203 725.3 * 337-0 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 : (1) 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 hied 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. 11 — 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. 1 to No. 8 were likely to prove of value where strength was required, and bars No. 9 to No. 18, 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. 327 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 -£jth 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 11 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 0.123 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 100 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. 1 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) inclusive the two 328 MATERIALS OF ENGINEERING— NON-FERROUS METALS. coincided, i.e., 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. 1 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. 1 was spongy and weak, as it was cast in sand ; No. 30 was strong and 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. Ail brittle alloys, and some possessing limited ductility, No. 8(76.64 copper, 23.24 tin) to No. 18 (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 not 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 tes^ 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), wdiich 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. 1 (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. 1 to 8 (all copper to 76.64 copper, 23.24 tin), inclu- sive, were turned in the lathe without difficulty, a gradually 330 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 - 9 1 t in ) 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. 1 (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. STRENGTH OF BRONZES. 33 * 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. 11 (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. 18 (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 0 with the former. Lustre, splendent. 3 3 2 MA TERIA LS OF ENGINEERING— NON-FERRO US ME TA L 5 . 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 ^ n )» — 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. 1 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 ti n )- — 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. n 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 tin). — 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 0 ; 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 STRENG TH 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 01,7.84 Sn. — Dimensions: Lengthy"; Diameter, 0.798". Load. Load per square inch. Elongation in 5 inches. Elongation in parts of orig- inal length. Load. Load per square inch. Elongation in 5 inches. Elongation in parts of orig- inal length. Pounds. Pounds. Inch. Pounds. Pounds. Inch. 5,100 10,200 0.01 .0020 14,610 29,220 0-37 .0740 8,000 16,000 0.02 .0040 14,650 29,300 o -39 .0780 10,000 20,000 0.03 .0060 Broke ii inches from C end. 10,760 11,4x0 21,520 22,820 0.05 0.09 .0100 .0180 Diameter of fractured section, 0.730 inch. No blowholes. 0 Set 0.08 Tenacity per square inch of original sec- 11,900 23,800 O.II .0220 tion, 29,300 pounds (2,090 kgs. per sq. cm.). Tenacity per square inch in fractured sec- 12,800 25,600 0. 14 .0280 13^4° 14,000 26,280 28,000 0.21 0.27 .0420 •° 54 ° tion, 35,000 pounds (2,461 kgs. per sq. cm.). No. 7 A.— Material : Alloy.— Original mixture: 80 Cu, 20 Sn. — Analysis: 80.99 Cu, 18.92 Sn. — Dimensions : Length, 6" ; Diameter, 0.798". 9 » 8 5 o 19,700 0.01 .002 14,000 28,000 0.02 .004 16,800 33,600 Broke in middle. Diameter of fractured section, 0.798 inches. One blowhole, irregular-shaped, about 0.10 inch diameter. Tenacity per square inch original section, 33,600 pounds (2,362 kgs. per sq. cm.). Tenacity per square inch, deducting blow- hole, 34,139 pounds (2,400 kgs. per sq. cm.). No. 33 B.— Material: Alloy.— Original mixture : 87.5 Cu, 12.5 Sn.— Dimensions : Length, 5"; Diameter, 0.798". 1,200 0.0025 .0005 2,000 0.0052 .0010 3,000 0.0097 .0019 4,000 0.0139 .0028 6,000 0.0206 .0041 8,000 0.0275 •0055 200 — 0.0008 (?) 10,000 0 0330 .0066 12,000 0.0396 .0079 200 0.0049 14,000 0 0473 .0094 16,000 200 O.054I 0.0200 .0108 18,000 0.0623 .0125 20,000 200 0.0709 0.0421 .0142 22,000 0.0793 .0159 24,000 200 0.0905 0.0665 .0191 26,000 0. 1040 .0208 28,000 200 0.1271 0.1063 .0254 30,000 0.1561 .0312 32,000 200 0.2007 0.1811 .0401 33,000 0.2270 •0454 33,200 0.2432 .0485 Broke in middle. Diameter of fractured section, 0.770 inch. Tenacity per square inch, original section, 33,200 pounds (2,334 kgs. per sq. cm.). Tenacity per square inch, fractured sec- tion, 35,648 pounds (2,508 kgs. per sq. cm.). STRENGTH OF BRONZES . 33 / TABLE LXIII. TESTS BY COMPRESSIVE STRESS. No. 31. — Material : Alloy. — Original mixture : 97.5 Cu, 2.5 Sn.— Analysis : 99.09 Cu, 0.87 So. — Dimensions: Length, 2" ; Diameter, 0.625". Load. Compres- sion. Load per square inch. Compression in parts of origi- nal length. Load. Compres- sion. Load per square inch. Compression in parts of origi- nal length. Pounds . Inch . Pounds . Pounds . Inch . Pounds . 150 .0000 16,000 - 395 I 52,152 • T 975 2,000 | .0018 6,519 .0009 18,000 • 5176 58,671 .2588 4,000 .0093 1 3,038 .0046 1 20,000 .6156 65,188 .3078 6,000 .0302 19,557 I .0151 | 22,000 .7266 71,709 •3683 8,000 .0609 26,075 •0305 1 24,000 .8483 78,228 .4242 10,000 .1077 32,595 •0539 25,000 ! .8801* 81,485 .4100 12,000 .1662 39 -H 4 .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 .4584 71,709 .2292 2,000 . 0000 6,519 24,000 • 5 i 5 i 78,228 •2575 4,000 .0000 13,038 26,000 .5778 84,747 .2889 6,000 .0002 19-557 .0001 28,000 •6393 91,266 •3197 8.000 .0108 26,075 .0054 30,000 .7000 97,780 • 35 oo 10,000 .0511 32,595 • 0255 32,000 •7499 104,303 •3749 12,000 .1219 39- 1 x 4 .0609 34.000 •8033 110,822 .4016 14,000 •1937 45,633 .0968 36,000 .8447 H 7 , 34 i •4223 16,000 .2648 52,152 .1324 38,000 .8918 123,860 •4459 18.000 20.000 • 33 10 •3951 58,671 65,188 • 1655 • 1975 40,000 •9330 130,379 .4665 No. 33.— Material : Alloy.— Original mixture: 87.5 Cu, 12.5 Sn.— Analysis : 88.40 Cu, 11.59 Sn.— Dimensions : Length, 2" ; Diameter, 0.625". 150 .0000 13,038 24,000 .3234 78,228 .1617 4,000 .0014 .0007 26,000 • 3575 84,747 • 1783 6,000 .0058 19,557 .0029 28.000 .4019 91,266 .2009 8,000 .0170 26,075 .0085 30,000 .4412 97,785 .2206 10,000 • 0374 32,595 .0187 32,000 .4815 104,303 .2407 12,000 .0711 39 ,H 4 •0355 34,000 • 517 1 110,822 .2585 14,000 .1166 45,633 •0583 3^,000 • 5534 H 7 , 34 i .2767 16,000 . 1636 52,1 52 .0818 38.000 ■5905 123,860 .2952 18,000 .2102 58,671 .1051 40,000 .6234 i. 3 o ,379 • 3 H 7 20.000 .2564 65,188 .1282 42,000 .6611 136,898 .3305 22,000 .2991 71,709 •1495 44,000 .6911 143,417 •3455 22 33& MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE LXIV. TESTS BY TRANVERSE STRESS. flo. 4.— Material : Alloy.— Original mixture : 92.8 Cu, 7,2 Sn.— Dimensions : Length between supports, 22" ; Breadth, 0.997" ; Depth, 1.012". Deflection, a. Set. Inch . Inch . 0.020 0.173 0.199 0.049 0.232 0 287 0. 116 0.348 0.429 0-49 1 0.584 0-379 0.620 0.781 0.858 1. 031 O 00 6 1-053 1 -155 1.289 1-384 1.824 1 -549 1.824 1-935 2.178 2.281 2.637 2-343 2.638 2.746 2.911 2.966 3.226 6.706 Tray reach Load. Pounds . 6 10 20 3° 40 60 80 100 *•0 T 5° 175 200 225 250 o 275 3°° o 3 2 5 35° 375 400 o 425 450 475 o 500 o 525 550 o 575 o 600 o 650 Inch . 0.0008 0.0016 o . 0039 0.007 0.010 0.013 0.017 0.020 0.024 0.029 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. 102 0.106 O.II2 o. 124 0.137 0.153 Set. Inch . 0.0008 0.0016 0.0024 0.0032 0.0055 0.0095 0.013 + 'o >, C/3 .tP ^ ■gjs 13,396,305 13,680,575 12,818,227 12,583,801 13,274,439 13,817,863 13,877, x 97 14,263,420 i3, 6 77,484 I 3,' 464, 355 12,548,648 11,853,945 Load. Pounds . o 750 800 o 850 900 o T 950 In 5 m. 1,000 In 5 m. 1,050 In 10 m. 1,100 In 10 m. 1,100 I , I 5° In 3 m. 1,200 In 10 m. o 1,200 T ,25 0 In 10 m. In 30 m. i 5 h 30™ o 1,250 1,300 In 10 m. In 30 m. i,35° _ + o tA fV C/3 Po 10,408,413 8,114,620 5,267,855 3,314,847 2,240,640 1,223,372 supports. Breaking load, P =- 1,350 pounds. Modulus of rupture, Rm = 3,074. 48, 73 1 * STRENGTH OF BRONZES. 339 TABLE LXIV. — Continued. No 32. — Material: Alloy.— Original mixture: 92.5 Cu, 7.5 Sn. — Dimensions: Length between supports, l = 22" ; Breadth, b = 0.956" ; Depth, d = 0.982". Load. Pounds. 10 4° 80 120 l6o 200 3 240 280 32° 360 400 3 440 480 520 560 600 3 600 Inch. 0.0060 0.0104 0.0x85 0.0278 0.0376 o . 0472 0.0572 0.0668 0.0769 0.0880 0.0983 o. 1105 0.1232 0.1389 0-1535 0.1719 o • 1963 0.2065 Set. Modulus of elasticity. _ PI 3 4 A bd* Inch. 0.0145 Beam sinks 0.0577 Resistance decreased in 2 m to Resistance decreased in i h 48 m 6,357.759 8,401,7(35 9,384,450 9,967,673 10,281,34.1 J 0, 564, 538 10,706,500 10,692,594 10,768,738 10,644,211 10,501,656 10,161,429 9,961,177 9,579, I 7 I 8,987,663 586 pounds, to 562 pounds, Load. Deflection. A Set. Pounds. Inches. Inches. 3 0.0655 600 0.2095 640 0.2365 680 0.2867 720 0-35 11 760 0.4609 800 0.6031 3 0.0413 800 0.6202 840 0.7792 880 0.0427 920 1-3217 960 T • 74 1,000 2.13 1,040 2.63 1,080 3.78 n.4.0 Modulus of elasticity. 4 & bd 3 7,957,28 i 6,030,003 3,900,466 [,380,404 840,132 Bar bent to a deflection of 8" without breaking. Breaking load (or the load causing deflection of 3J") 1,080 pounds. 3 PI Modulus of rupture, R — - — — = 38,659. Rm = 2,718. No. 7. — Material: Alloy. — Original mixture: 80 Cu, 20 Sn.— Analysis : 80.95 Cu, 18.84 Sn.— Dimensions: Length between supports, 22" ; Breadth, 0.998" ; Depth, 1.011. 100 125 is 3 J 75 200 o 225 250 275 3°° 3 325 35° 375 400 o 425 450 475 500 o 525 55° 575 600 o 625 650 700 o 750 800 o 850 0.025 0.028 0.033 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 0.103 o. 105 0.114 0.122 0.128 O.I32 O.I4O 0.155 O.167 O.I72 O.OO24 O.OO39 O.O063 O.O063 O.OO39 O.O063 737, 827 11,891,996 12,045,639 12,487,468 12,245,726 12,855,428 !2, 455, 356 12,517,091 12,874,176 13,274,787 12,779,097 12,979,791 12.426,896 900 o 950 I ,°5° o 1,100 1,200 o i,3°o o 1,400 o 1,500 o 1,600 o I ,7°o o 1,650 In 15 h o 1 ,520 i,75o V>. 184 o. 192 0.201 0.219 o. 256 0.285 0.320 0.360 0.415 0.470 0.510 0.537 0.0103 0.012 o OI 3 0.026 0.039 0.055 0.075 0.099 0.126 12,681,589 12,893,200 13,012,118 12,139,743 11,810,161 11,325,050 10,783,714 9,976,527 9,355,254 9,202,114 0.169 0.469 Broke 10 seconds after putting on the last pound of the weight. Breaking load, 1,750 pounds. Modulus of rupture, *= J^ (i °+ 3>=5*0 O cocoTj -0 m • ^ m ^ 0 6 Thvo rt- cn m m H H N 2 H H 3 a O V ‘jfl 0 Fb ■uinuiixBui JO S 3 SBJU 3343 d •Jiuiq DUSBia 10 CO 00 O lO’t meow 00 m cn ^ mvo vo cn^t • moo mHoo^MCNMQQO - mmcn^cnN- mvo 0 0 0 • uinuiixBj\[ VO ^vO ^ ^.VO ON xf ! r? Si m rn 6 S ^ vo m cn h moo m cn vo mvo m ^00 • ovOvocNOmoHONMmm • vo 0 vo moo woo 0 mw ms • mvo m t*>. c^oo on on m cn co h COMPRES- SION TESTS. •qjSuai ibuiSuo jo saSBjuaojad ‘uoiss 34 duioo jo junouiy + + + 0 0 0 + + ! + ! + ;+ . o 5 • T 00 - 0 - 0 - O '^’q 5 ' ■qoui 94 Bnbs 43d spunod k qjSu 34 js SuiqsiLQ On CN* r co ^ r 0 c 7 cT • ocT • m '.00 • ivo • ^ • m • m • • m . • TESTS BY TENSILE STRESS. •JBUI - 3 l 40 JO S 3 J§BJU 3343 d ‘UOlj - 33 S P 34 UJ 3 B 4 J JO 43 J 3 UIBIQ VO CN Ov On vo cn 00 m t^oo Q Q Q 0 0 Q O 00 Cnoo OnOnOnOOOOOOO H H H H M H b* •qjSuaj jbuiSuo jo sj 4 Bd ui ‘uoijBSuop jbjox H on m mvo vo cn h 0 Th • • • • cn m tj-vo m m rt- m • • • • Tt- m m m m 0 0 0 • • • • hOOOOOOOO • • • • •pBOf SutqB 34 q JO S 3 SBJU 3043 d’ l JlUiq OIJSBia cn 00 VO M 00 10 0 vo pi vo m 0 • • 0 « oco f^oo . -0 0 0 0 0 mio >n mvo iO • • 0 O 0 0 0 • • H M H H H 3 0 Sgsr- •uoij - 33 S p 34 njDB 4 X NVO el 00 O'* ^ Ov Tf pi o ro m m 0 O 0 0 mmo O' oc oo 0 moo -tf-oo m m O'OO pi lO N PI Cl h so m C 3"0 0 -T mvo pi n-PO rnOiO pi pf-Pi'O mH Tt-mmmmmmmpi pi ‘UOIJ “ 03 S JBUISUQ ^vg § *3 CN r^.VO rh ^ • ONM^ w m o H m mocf O' 0 • tCvcT O' cT C? CN O* m t co rj-vo • vo m cn m m •AXIAVHD DIXI 33 * ON VO CN rh 0 00 t"s CNJ 0 t^*VO CN ON 00 • • On ON ON On On On 00 00 00 00 N N t'xVO VO COMPOSI- TION OF ORIGINAL MIXTURE. u?X QOOOmOOQOmOOOooOQm 5 0 O' m p^ pi 10 5 uvt wi O 1 niO uio N 0 0 M PI PI N ts O PI PlSO N m p. O • 43 ddo 3 QQOO^OONOOi-sOOOCNOOm 0 0 w m (N 00 mo m m m 0 m m m 0 cn Q 0 00 P.IO PI N O t^lO PI 0 P-.'O PI 0 00 0 0 O' O' O' O' O' O'OO 00 00 00 p^ P^ P-.'O •NOIXNOdOHd DIIAIOXV : • 3 ; 3 3 : : : 3 : : ; 3 : : 3 • -u -uu ■ : *u • • u • -u 33 c:cc ,, :c:;:c::c uUt/i • co c n ■ ■ -w • • c/3 - c/3 •aaawnN j ■3t ■X 1 ■+- h 0 w h cotw m cno ^ moo vo 0 0 coco co co CO CO CO M STRENGTH OF BRONZES. 343 DO VO in nvo m 00 On 00 0 rOHCMMTf 0 M(N h 6 6 o’ o do m m VO vo o o o o o o’ o o 0 0 0 H On O On ^-00 vo COO'N mi OvN h row O O O O 2 8888888 O N h ro fsVO t-s Ooo Oo m •• ~ ts 0 s|- © t"00 00 NN ^■NfOO'O M moo On 0©dst-mCsmomO'*-oooc?> mvo cs moo no m m m mvo vo oo uinno mo mns mOOmOhOhhhOhhhmm , m o t»"o h h oo o n ts mvo h n mvo m cs o vo oo mm m h n m m m m 88888888888888 o •'t* m on m h vo ■ co Nm moo in n« m m m » ON on O' on N N t^vO VO m i VO vo On t^OO C On (N m oo vo o '<*■ CN H o o OVOCO M £"i t^OOOOOQH^OOO QMONM(N 0t^(N ^-00 ^ o 0 “ h(n 0 mN’tH Tf ■>OJ(NN VO cn S 6 2 £ fl Q S +- £ o >* '> 03 & ^ tut) *3 ■yA 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 Fig, io. — Strain-diagrams of Bronzes in Compression. 347 STRENGTH OF BRONZES. Compression in Parts of Original Length. 34^ 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 (cop- 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 n. Compositions approaching copper, 80, tin, 20, exhibit the greatest strength under this form of load. Those having less tin (6 to 10 per cent.) as Nos. 4, 5 (copper, 93 ; copper, 90), are evidently vastly better to resist the shock of suddenly applied loads and safer against accident ; Fig. ii. — Strain-diagrams. Bronzes as Beams. STRENGTH OF BRONZES. 349 350 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 oh 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 17 y 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 Fig. i2.— -Comparison of Resistances. 352 MATERIALS OF ENGINEERING— NON-FERROUS METALS. bD C C Composition by Analysis STRENGTH OF BRONZES . 353 from the maximum to minimum strength which does not have any relation to the atomic proportions. 21 1 . 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 y 2 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 ]/ 2 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 tin) gave maximum transverse re- silience within the deflection of 31^ 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, which 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 “ 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* STRENGTH OF BRONZES . 355 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 lower than that of alloys given by other authorities, and for this reason the density of No. 6 A (87.15 copper, 12.69 tin) in 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— NOE-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°.i cent.). If the formation of the gas which causes blow-holes can be prevented, or if it can be removed froin 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 Composition 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 3 , 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 copper 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 ioo 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- centage 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. Fig. 14. — Ductility of the Copper-tin Alloys. 360 MATERIALS OF ENGINEERING— NON-FERROUS METALS c Composition by Analysis S I REA GTH OF BRONZES . 36I 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 are 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 Fig. 15.— Conductivity of Copper-tin Alloys. 362 MATERIALS OF ENGINEERING— NON-FERROUS METALS Composition 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 3 j 4 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 Fig. 16. — Properties of Copper-tin Alloys. 364 MATERIALS OF ENGINEERING— NON-FERROUS METALS. COPPER 95 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. 3 6; 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, 1, 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 COMMERCIAL COPPER. BRASS. OPEN HEARTH STEEL. Lbs. Kilogs. COPPER. Unannealed. Annealed. I. n. 500 600 800 1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800 227 272 363 454 499 544 59 ° 635 680 7 e6 771 817 O.024 0.040 0.078 0-155 0.005 0.020 0.063 0.156 0.266 j 0.005 0.0x5 0.040 0.087 0. 1:30 0.21:4 0.290 0.033 0.050 0.075 0. 102 0.152 0.266 co. 27 0.057 0.085 0. XIO 0.163 0.270 0.013 0.025 0.042 0.062 0.085 0.117 0.157 0.217 0.322 0.050 0.075 0. 100 0.130 0.165 0.220 0.350 0.0225 0.030 O.0425 0.060 O.O775 0. 140 O.23O 0.005 0.0075 0.013 0.030 0.065 0.126 * 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 LXVII. TENACITY OF STERRO-METAL. MATERIAL. TENACITY. Lbs. per sq. in. Kilogs. per sq. cm. Sterro-metal ; cast 60,480 4,252 “ forged 76,160 5,354 “ cold-drawn 85,120 5,984 Gun-bronze ; cast 40,320 2,834 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. The 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 and Armor,” p. 424. STRENGTH OF BRASSES. 369 TABLE LXVIII. MODULI OF ELASTICITY OF BRASSES. METAL. VALUE OF E. AUTHORITY. REMARKS. Lbs. on sq. 1 in. Kilogs. on sq. cm. Brass. 9. 000,000 12.000. 000 13.000. 000 632,700 843,600 91:3,900 Tredgold. Wertheim. ) Bauschinger. ) 11 tin, 89 copper, cast. 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^ 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. 24 370 MATERIALS OF ENGINEERING— NON-FERRO US 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 haif 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 percent, 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. 1 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 and 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 _ P(f -i) Pc f t\ in which P is the weight of the water, P the weight of metal poured, t 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. Number. Composition by original mixture. Weight grammes. Temperatures, Fahrenheit, Degrees. Assumed specific heat. Temperatures of casting. Degrees. Remarks. Copper. Zinc. Water. Metal. Initial. Final. Range. Fahren- heit. C e n t i - grade. 1.. 95 5 9°7 131.8 54 114 60 0.09517 4454 2456.7 Second casting. 2.. 90 10 907 212.3 53 118 65 0.09519 3035 1667.6 3» ■ 85 1 5 9 °7 321.4 55 i55 100 0.09521 3120 ^S-S Poured thick. 4.. 80 20 907 447-3 58 172 114 0.09523 2600 1426.6 5-- 75 25 907 381.26 54 i54 100 0.09525 2652 1455-5 6. . 7° 30 907 257-9 52 120 68 0.09527 2631 1443.8 7-- 6 5 35 907 259.9 56 120 64 0.09529 2464 *35* 8.. 60 40 907 340-5 65 J 5 2 87 0.09531 2584 I4I7-7 9-- 55 45 907 182.6 61 109 48 0.09535 2610 1432. 1 ro. . 50 5° 907 199.5 54 104 50 0.09535 2492 1366.5 11 . . 45 55 907 237.4 53 102 49 0.09537 2065 1129. 7 12. . 40 60 907 223.3 61 112 5i 0.09539 2284 1251. 1 1 3-» 35 65 907 185.9 57 IG2 45 0.09541 2403 1 3 I 7-3 14.. 3° 70 907 203.6 60 no 50 0.09543 2444 1340. 1 Second casting. !5.- 25 75 907 168.0 61 98 37 0.09545 2191 H99-5 Second casting. 16. . 22.5 77-5 Not taken. 17.. 20 80 9°7 169.3 5 1 .85 34 0.09547 1994 1089 . 6 Second casting. 18.. 15 85 9 : 7 316.0 56 16 60 0.09549 19.. 10 90 9°7 j 289.5 54 106 52 0.09551 1812 988.9 Second casting. 20. . 5 95 907 163.0 60 *73-5 J 3-5 0.09553 860 460.0 21. . 0 100 4535 597-3 53 ! ! 70 20 0.09555 1660 904.1 224. External Appearance of the Bars. — The surfaces of bars No. 1 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. 1 (5 per cent, zinc, original mixture) was variegated in color, exhibiting iridescence in places, the prevailing tints being 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. 1 to No. 7 (5 to 35 per cent, zinc), were smooth. No. 8 (40 per cent, zinc) was lough, the rough- 372 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 11 (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. 1 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. 11 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. , i860, p. 54. STRENGTH OF BRASSES . 373 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. 1 (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- ling No. 1, 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 ^)- — Surface in character re- sembling No. 3, but less acutely jagged. Color, brass-yellow. No, 5 (76.6 5 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 ( 5 5- 1 5 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. 11 (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. 5 TRENG TH OF BRA SSE S. 37 5 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. 18 (14.19 copper, 85.10 zinc). — Closely resembling No. 1 7. 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. Number. | COMPOSITION BY ORIGINAL MIXTURE. WEIGHTS, GRAMS. TEMPERATURES, FAHRENHEIT. (degrees.) ASSUMED specific heat. TEMPERA- TURES OF CASTING. (degrees.) REMARKS. Copper. tj ' g N Water. Metal. Initial. Final. Range. Fahrenheit. Centigrade. J2 Q7. 5 2. S Temperature not taken. 23 92.5 7-5 9°7 167.26 64 112 48 0.09518 2847.2 1:564. 24 87. 5 12. 5 907 Temperature not taken. 25 82.5 17-5 907 277.17 64 140 76 0.09522 2752.3 I 5 II *3 26 77-5 22.5 907 482.59 68 188 120 0.09524 2558.7 i4°3 -7 27 72-5 27.5 907 426.95 60 158 98 0.09526 2343-9 1284.4 28 67.5 32. 5 9°7 577-7° 64 180 ir6 0.09528 2091.8 IT 44.3 29 62.5 37-5 907 439-55 63 168 io 5 0.09530 2441.9 1338.8 30 57-5 42.5 9°7 397-42 58 158 100 0.09532 2552-7 1400.4 3 1 52.5 47-5 907 339-°5 60 142 82 °-°9534 2444.3 1339-5 32 47-5 52.5 907 29 6 -53 54 130 76 , 0.09536 2568.2 1409. 33 42.5 57-5 907 388.15 68 158 90 0.09538 2363-3 1295. 1 34 37-5 62.5 907 327.33 64 142 78 0.09540 2407.9 I 3 I 9-9 Mixed well; poured hot. 35 37-5 67-5 907 224.45 88 138 5° 0.09542 2255.8 i 2 35-4 Considerable zinc vola- tilized - poured thick* 36 27-5 72.5 907 221.19 66 112 46 0.09544 2088 . 7 1142.6 37 22.5 77-5 9 °7 322.52 62 125 63 0.09546 1981.3 1082.9 38 T 7-5 82.5 9°7 278.40 59 104 45 0.09548 1639-7 893.1 39 12-5 87.5 9°7 165.18 68 95 27 0.09550 1647.7 897.6 40 7-5 92.5 907 197.87 55 92 37 0.09552 1867.9 1019. 9 4i 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 ANALYSES. VARIATION OF MEAN MIXTURE. COMPOSITION. ANALYSES. H > 0 77. K O G C U S w > « u u c u « s Zj £ a a 0 u d G N a a, 0 u d c N a a 0 U d a N a a 0 U d c N 0 w Dh ir . 2 0 < u s I A.... i B.... 95 95 5 5 95-98 96.10 3-90 3-68 + 0.98 + 1. 16 — 1. 10 -1.32 j- 96.07 j 8.795 3>79 n s.sS [8.825 2 A.... 90 10 90.49 9.48 + 0.49 —0.52 [ 90-56 9-4 2 J 8.758 [8.773 2 B.... 90 10 90.62 9-35 + 0.62 —0.65 1 8.788 3 A.... 85 15 89.31 io-54 + 4.31 —4.69 [ 89.80 10.06 j 8.643 [8.656 3 B 85 15 90.29 7-57 + 5.29 -5.43 | 8.669 4 A.... 80 20 81.97 17-95 + 1 97 — 2.05 j - 81 .91 17.99 j 8.603 [8.598 4 B... 80 20 81.85 18.03 + 1.85 -1-97 1 8.593 5 A.... 5 B.... 75 75 25 25 77.84 75-45 21.78 24-37 + 2.84 + 0 45 — 3.22 —0.63 [76.65 23.08 J 8-539 1 8.517 [8.528 6 A.... 6 B.... 70 70 3° 30 7 1 -34 71 .06 28.55 28.52 + 1 34 + 1 .06 -1-45 -1.48 [71.20 28.54 j 8.458 j 8.429 [ 8.444 7 A ... 7 65 65 35 35 67.24 65.29 32.49 34-5i + 2.24 + 0.29 -2.51 -0.49 [ 66.27 33.50 J 8.392 1 8.350 [ 8.371 8 A.... 8 B.... 60 60 40 40 62.68 59-19 36.91 40.39 + 2.68 —0.81 -3.09 + 0.39 [60.94 38.65 j 8.443 1 8.367 [ 8.405 9 A.... 9 B.... 55 55 45 45 59- 13 51-16 40 36 48.52 + 4- T 3 -3-84 -4.64 + 3.52 [5515 44-44 1 j 8.369 1 8 . 196 [8.283 lo A . . . . io B 50 50 50 5° 52.21 47- 11 47.48 52.79 + 2.21 — 2.89 -2.52 + 2.79 | 49.66 50.14 j 8.301 j 8.281 [8.291 ii A... 45 55 47-45 52.35 + 2.45 — 2.65 [47-56 52.28 "1 8.189 t ii B . . . . 45 55 47.67 52.20 + 2.67 — 2.80 f 12 A 1 2 B. . . . 40 40 60 60 42.09 40.51 57.32 58. 9 1 + 2.09 + 0.51 -2.68 — 1.09 [41.30 58. :2 j 8.c6i \ 8.061 [ 8.061 13 A.... 13 B.... 35 35 65 65 36.52 36.72 63.20 62.36 + ^.52 + 1.72 — 1.80 — 2.64 [ 36.62 62.78 j 7.988 1 7-959 [7.974 14 A.... 14 B 3° 3° 70 7° 3!.i7 34-71 67.84 64.62 + 1.17 + 4.71 — 2.16 -5-38 [32.94 66.23 j 7.847 1 7-775 [7.811 15 A.... 15 B... 25 25 75 75 25-56 25.98 74.00 72.90 + 0.56 + 0.98 — 1 .00 — 2.10 [25.77 73-45 J 7-627 1 7-722 [7.675 16 A 16 B.... 22.5 22.5 77-5 77-5 26.44 25.40 72.73 73-38 + 3.94 + 2.90 -4-77 -4.12 [25.92 73.06 j 7.694 1 7 684 [7.687 17 A.... J 7 B .. 20 20 80 80 21 .00 20.61 77-59 77.67 + 1 .00 + 0.61 -2.41 -2.33 [ 20.81 77.63 j 7-5oo 1 7.336 [7.418 18 A.... 18 B... 15 15 85 85 13- 86 14- 5 1 86.03 84.16 -1.14 -0.49 + 1.03 —0.84 [14.19 85.10 j 7.166 1 7- I 59 [7.163 19 A 19 B 10 10 90 90 10.41 10.19 89.02 88.74 + 0.41 + 0. 19 — 0.98 — 1.26 [10.30 88.88 j 7.181 1 7-325 [7.253 20 A . . . . 5 95 4-33 94.69 —0.67 -0.31 [ 4.35 94-59 j 7-177 7 108 20 B 5 95 4-36 94.48 —0.64 —0.52 1 7-038 S 7-ioo 21 A 0 100 7.140 7 .!46 [7.143 21 B 0 100 1 1 37 & MATERIALS OF ENGINEERING— NOX-FERROUS METALS TABLE LXXI. — Continued. Second Series. ORIGINAL MIXTURE. ANALYSES. VARIATION OF COMPOSITION. MEAN ANALYSES. 1 Number. Copper. d c N Copper. Zinc. Lead. j Copper. Zinc. Copper. 1 22 A 97-5 2. r 97-98 1.60 None.* + 0.48 —0.90 t m 0- 22 B 97-5 2.5 97.68 2. j6 None.* + 0.18 -0.34 | 97.03 23 A 92. 5 7.5 92.65 7.42 Trace. + 0.15 —0.08 1 23 B.... 92.5 7-5 91.99 7.94 Trace. —0.50 4-0.44 1 92.32 1 24 A 87-5 X2.5 88.86 11.06 0.12 + 1.36 -1.44 1 1 QQ n . I 24 B ... 87.5 12.5 89.01 10.88 0.16 + 1.51 — 1.62 1 j 00.94 25 A 82.5 * 7-5 82.85 17.06 0.17 + 0.35 -0.44 i ^ O _ 25 B.... 82.5 47-5 83.00 16.90 0.16 + 0.50 —0.60 I f ° 2 -93 26 A. . . . 77 - 5 ! 22.5 79-13 20.77 0.06 + 1.63 - 1-73 1 77.39 26 B.... 77-5 22 . 5 75.65 24.12 0.14 -1.85 4-1.62 i 27 A.... 72-51 27.5 75-13 24.51 0. 16 4-2.63 -2.99 1 - 73 20 1 27 B 72.5 27.5 71.27 28.42 0.21 -1.23 4-0.92 j 28 A.... 67-5 3 2 - 5 70.65 29.16 0.19 + 3 .15 - 3.34 1 - f\r\ n a 28 B.... 67-5 32.5 68.82 30.95 0.23 4-1.32 -r .55 1 , *74 29 A 62.5 37-5 63.36 36.46 0. 10 4 - 0 . 86 -1.04 1 - 63 AA 29 B . . . . 62.5 37 - 5 ! 63.52 36.26 0. 12 4 - 1 .02 -1.24 1 30 A 57-5 42. 5 ' 58.22 41.25 0.47 4-0.72 -1.25 l » c8 AO 30 B ... 57-5 42-5 58.75 40.94 0-37 + 1.25 -1.56 j 31 A.... 52-5 47-5 55.02 44-57 0.40 4-2.52 -2.93 1 - u 86 31 B.... 52 - 5 ) 47-5 54.69 44-99 o -34 | 4-2.19 -2.51 ( 32 A.... 47-5 I52.5 49.05 50.71 0.32 + i -55 -1.79 1 - a8 0 ? 32 B 47 - 5152-5 48.85 50.93 0.26 + 1-35 — 1 - 57 ( 33 A.... 42-5 57-5 43-68 55.89 0.41 + 1 . 18 — 1. 61 i - A 3 36 1 33 B.... 42.5 57-5 43-04 56.55 0.34 + 0.54 -0.95 1 34 A 37-5 62.5 38.25 61 . 18 0.62 + 0.75 -1.32 1 t- ^8 36 34 B . . . . 37-5 62.5 38.46 60.92 0.58 -t-0.96 -1.58 1 35 A.... 32.5 67-5 35-83 63.55 0.66 + 3-33 - 3-95 1 ► or 35 B.... 32.5 67.5 35.52 63.87 0.66 + 3.02 -3-63 i , 35 « uo 36 A 27-5 72.5 28.78 70.59 0.55 4-1.28 -1. 91 I 36 B . . . . 27-5 72-5 29.62 69-75 o -55 4-2.12 -2.75 ! 29.20 37 A.... 22.5 77-5 21.77 77.40 0.70 — 0-73 — 0. 10 1 ”21. 82 37 B. ... 22.5 77-5 21.86 77.46 0.63 — 0.64 — 0.04 1 38 A.... * 7-5 82.5 17.16 81.87 0.99 — 0.34 — 0.63 1 38 B.... 1 7 - 5 82.5 17.81 81.36 0.86 4-0.31 -1. 14 I " 1 7 • 49 1 39 A.... 12.5 87.5 n -75 87.19 0.99 -0.75 —0.31 1 * jf&> ^ 12 39 B.... 12.5 87-5 12.48 86.14 1.22 —0.02 — 1.^6 ! 40 A 7-5 92 -5 7- I 9 92.34 0-54 -0.31 —0.16 1 40 B 7-5:92-5 7.21 91.79 1.02 — 0.29 — 0.7 1 1 7.^0 41 A . . . . 2 - 5 ' 97-5 2.63 96.20 i.c8 4 -o. T5 -1.30 1 41 B.... 2-5 97-5 2.26 96.65 1.02 1 --0.24 —0.85 ! r 2 - 4S Zinc. Lead. 1.88 0 1 7.68 Trace -j 10 -97 0.14] 16.98 °- I 7 j 22.45 o.ioj 26.47 0.19-j 30.06 0.21 f 36.36 41.10 0.42] 44.78 0.37] 50.82 0.29I 56.22 0.38 -j 61.05 0.60 -j 63-71 0.66 -j 7 °. 17 0.55 J 77-43 0.67 j 81.62 0-93 ] 86.6 7 1. 11 92.07 00 0 96.43 1.05] 8.786 8.796 8.724 8.767 8.764 8.729 8.662 8.603 8.607 8.542 8.511 8.418 8.401 8.366 8.417 8.405 8.367 8.358 8.322 8.280 8.228 8.203 8.068 8.999 7.987 7.976 7-973 7-959 7-785 7.746 7-452 7-379 7.231 7.218 7.258 7.217 u.yuo 7.177 6.982 I r 1 r ) r f f u > 55 PS < o 8.791 8.746 8-747 8-633 8.574 8.464 8.384 8.411 8.363 8.301 8.216 8.034 7.982 7.966 .7.766 7.416 7.225 7.238 7-I3I 7.080 228. 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 of more tests each. * No. 22 A had 0.37 per cent, iron and 22 B 0.24 per cent. iron. The others had no iron or only traces. ALLOYS OF COPPER AND ZINC. STRENGTH OF BRASSES. 37 * g w cl, h S 2 O O u rs •AjpijsBp jo sn^npop^ | ’(Spunod-JOOj) 33U3I|IS3^I rovo n hm rooo \o t~- i . io\o in (T)VO vo »n •aaqy j ujsjxs jo uouusjxg •(soojSop) uois -joj jo spguy C G O U ■g s t2i •(mnunxBui jo ‘juaD Jod) iiunppsBp jy (spunod-jooj) uinuuxBp\[ •(•JU33 aod) uoiss34dui jo junoaiy o W o O M o HHOOOOOOOO OOOOOOO0O0O . cnoo 00 00 n N’t t^OO O i VO (N 00 N VO. ON H ' On VO O m (N O N W N « M N m (N 00 cn CM VO O N LO On O cn o On ’ + : + o • o •(spunod) qoui o-renbs 43d qjSusajs Suxqsru3 •(uoipss peuiSuo JO *JU30 43d) UOIJ33S psxnpBJj jo jspuxbiq; •(•juoo 43d) uoijBSuop pjox •(pBO[ Sai5[B3jq JO •JU33 J3d) juxiq DijsBia «-S aj, '55 j5f> 3o O - , , ,, r~> •(spunod) uoij -03S psanjDBJX •(spunod) uoij -33S JBUlSuQ •AjpiiSB[3 jo sn[npop\[ •(spunod-jooj) S3qOUT JO UOIP3JJ -3p B UjqjlM. 3DU3qiS3'a •(ssqoui) SuiqB34q 340J3q UOIJ33JPP [BJOX "(pBOJ Sui5JB3jq JO •JU33 43d) junq di;sb [3 •34njdnj jo snjnpop\[ •AXIAVMO DIXIDHJS NV3IM S ® cn 8 | £ < E < W C/) £ £ ? < Ns Ns N.VO ■ O N* M o cm co cn cm H VO O VO l CNJ ’tmN't N.VQ i On vo On N*oo cn O 00 00 00 LO On N io in cnvo vo m 8 8. ft! VO vo VO i 0) w 10! in N*vo OnvO On Ns m m (N Tt m on w ro On n N (N (N ON N On in m w m hT O O rnvO m O rn ’t m o m oo m cm CO On On h vo f^OO 00 On cccccccccc oooooooooo CQ PQ CQ CQ PQ PC CO ffi PC PQ O CN Tj- H 6 cn h vo in ttnO oo cnoo » N- N.VO vo m i COOOOOOOOOCOCOOOCOCO! ON 0 On On ' H rn Ns on O O VO Ns I g 2 G X oo o cn m on oo on on cnvo NsVO (N 0-00 On CM w NsVO cn m ONVO On O' On Onc I 00 00 N N N NsVO VO VO VO o m o mo Cu • • • • mNO O w O m O m O m O . . . m cm o n. m (n o (J On On On On 00 00 00 00 0 m o mo m O cs o Ns in CM Ns NsVO VO VO ' cn m 'Tfvo m c^o oo N* Onoo TABLE L XXII . — Continues 380 MATERIALS 01 ENGINEERING.— NON-FERROUS METALS. •AjrspsBp jo snjnpoj^ | ‘(spunod-JOOj) 3 DU 3 TpS 3 -JI d *j a a o w so h ro O' ^so h moo n in (> tC rf-vcT cm h O' O vo • (spunod- jooj) ssqoux jo uoposp -3p B Uiq^TM 33U3I[IS3~a •(ssqoui) Sui5[B34q 340j3q uopospsp IB)OX •(PBOT Sui3JB34q JO •JU33 43d) jiuiq OlJSBia • 34 n}dn 4 jo sninpopi moo m m on m on cm vo O m H VO CM M-ONH I>s I C d m H VO On 1 . - DCL).oo !8 8 8 8 8 8 8 8 8 8 8 8 8 iKS&{j> TfVO NNN NON * t^vo ^00 00 vo cm m on cm n -r+- r-r rr\ -*d- t 4 - H HCMCM CS •AXIAVHO DIJIDSdS NV3W -d-vo h vo >0 t^vo 00 to ro 00 ro h 00 O ro S OH :o?tSc» Svo Hvg^oo hhcjvo rotoroow £ ro N ro N M ■ O O OiOt ChOO l^tO to h m n h h o w 00 00 00 00 00 OOOONNtsNt'Nt'f' N( ' SlsNNNNN S « ui 8 §^ Zn 2 S 2 ?'oto 2 tL §8 0 ®? : R.RRfcW3 d w ^ CQ 2 « O ^ D Zn inO too too too mo mO mo mm 0 mo mo m 0 m 8 t^S^g 8 ^ § I Cu too mo mo mo mmmo_ to 0 m m 0 m o to o m 0 m « N.ION o’ lA to N* O NON O NON N 0 N lO N 0 NmN(J mmmm^^-^Tfm mmcMCMCMCMCMHHHH •aaawnN OONHOCMMmcMTt-mm ^vo mvo r>. r^oo oo 2 s 2 - S 3 - m ro mH m m m h m m m m m h h m h com m h cm STRENGTH OF BRASSES. 381 229. 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 calculated 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 0.01 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. 11 (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 the same composition 384 MA TE RIALS 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 10 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. 3 8 5 seen on comparing the data obtained from good specimens of brass, as T — 30,000 + 500 z. 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 52.9 per cent., the resistance decreased to 1 10,000 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 elliptical. 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 w T as 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. 11 (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 110,822 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 to 5.85 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. 1, 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 to 33 - 5 ° zinc) inclusive, with also, probably, Nos. 1, 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. 11, 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 STRENGTH OF BRASSES. 38 9 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 11 (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. 11 (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 390 MATERIALS OF ENGINEERING— NON-FERROUS 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. STRENGTH OF BRASSES. 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 52.28 per 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. 11 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. 11 (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. 13 C (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 39 2 ma te rials 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 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 -S’ is taken to measure the difference between the percen- tage of zinc present and that of maximum resistance, 45 pet cent., a rough estimate may be taken, as Sz = SO , OOO - 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 TRASSES. 393 In metric measures, S\m 3 1 5 1 5 2 4 A s » J'i* = 3.515 - 211 A s. 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 =C. 798". BAR NO. 25 B. Composition. — Original mixture : Cu, 82.5 ; Zn, 17.5. Analysis : Cu, 83.00 ; Zn, 16.90. LOAD PER SQUARE INCH. ELONGATION IN 5 INCHES. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds . Inch . Inch. 1,000 0.0014 O.O3 2,000 0.0037 O.O7 4,000 0.0104 0.21 200 0.00x7 6,000 0.0230 O.46 7,000 0.0326 O.65 8,000 0.0412 0.82 200 0.0322 9,000 0.0500 I. OO 10,000 0.0616 I.23 11,000 0 . 0840 1.68 12,000 0.1154 2.3I 200 O.IIOO 13,000 0.1483 2.97 14,000 0.1880 3-76 15,000 0-2344 4.69 16,000 0.2747 5-49 200 0.2676 LOAD PER SQUARE INCH. ELONGATION IN 5 INCHES. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds. 17,000 Inch. 0.3194 Inch. 6 -39 18,000 0.3600 7.20 19,000 0.4034 8.07 20,000 0 . 4460 8.92 200 0.4404 21,000 0.4892 9.78 22,000 0-5274 10.55 23,000 0.5586 Measuring a ipparatus slit II. 17 >ped. 24,000 32,800 Broke 2 inches from D end. Total elongation measured after breaking, 1. 17" = 23.4 per cent. Diameter of fractured section, 0.608". Tenacity per square inch original section, 32,800 pounds. Tenacity per square inch fractured section, 56,493 pounds. 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. LOAD PER SQUARE INCH. ELONGATION IN 5 INCHES. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds. 2,000 Inch. O . 0040 Inch. O.08 3,000 0.0062 0.12 4,000 0.0100 0.20 5,000 0.0144 O.29 6,000 0.0215 0.43 7,000 0 . 0299 O.60 8,000 0 . 0368 0.74 200 0.0221 9,000 0.0443 0.89 10,000 0.0518 1.04 11,000 0.0646 1.29 12,000 0.0698 1.40 200 0.063 6 13,000 0.0878 1.76 14,000 0.1133 2.27 15,000 0.1513 3-03 16,000 0.1867 3-73 200 0.2348 0,1784 17,000 4 - 7 ° ! 18,000 0.2813 5-^3 LOAD PER SQUARE INCH. ELONGATION IN 5 INCHES. SET. ELONGATION IN PER CENT. OF LENGTH. j Pounds. Inch. Inch. 19,000 0.3326 6.65 20,000 0.3834 7.67 200 0.3724 8.67 21,000 0-4334 22,000 0.4846 9.69 23,000 0.5380 IO.76 24,000 0.5938 11.88 200 0 00 00 25,000 0.6480 12.96 26,000 0.7156 14.31 27,000 Measuring apparatus slipped. 36,840 Broke 2 inches from B end. Total elongation measured after breaking, 1.27" = 25.4 per cent. Diameter of fractured section, 0.587 Tenacity per square 36,840 pounds. inch, original section, Tenacity per square inch, fractured section, 68,064 pounds. bar no. 29 B. 1,000 0.001 1 0.02 2,000 0.0034 0.07 3,000 0.0055 O.II 4,000 0 . 0078 0.16 5,000 0.0100 0.20 6,000 0.0121 0.24 7,000 0.0142 0.28 8,000 0.0166 °-33 9,000 0.0191 0.38 10,000 0.0218 0.44 11,000 0.0257 0.51 12,000 0.0293 0-59 200 0.0075 13,000 0 . 0336 0.67 14,000 0 . 0392 0.78 15,000 0.0452 0.90 16,000 0.0520 1.04 200 0.0322 17,000 0.0643 1.29 18,000 0.0678 i .35 19,000 0.0812 1.62 20,000 0.1061 2.12 200 0.0814 21,000 0. 1142 2.28 22,000 0.1350 2.70 23,000 0.1571 3-14 24,000 0.1836 3-67 200 0.1683 Zn, 37-5- Analysis : Cu, 63.52 ; Zn, 36.26. 25,000 0.2097 4.19 26,000 0.2371 4-74 27,000 0.2668 5-34 28,000 0.2961 5 - 9 2 200 0 29,000 0.3287 6-57 30,000 0.3665 7-33 31,000 0 . 3988 7.98 32,000 0.4260 8.52 200 0.4252 33,000 0.4790 9.58 34,000 o- 5 i 73 10-35 35,000 0-5585 11. 17 36,000 0 . 6090 12.18 200 0.5886 37,000 _ 0.6548 13.10 Measuring apparatus slipped. 47,840 | Broke 1 inch from B end. Total elongation measured after breaking, 1.62" = 32.4 per cent. Diameter of fractured section, 0.656". The piece drew down very uniformly through the whole length to a diameter of about 0.685". Tenacity per square inch, original section, 47,840 pounds. Tenacity per square inch, fractured section, 70,772 pounds. STRENGTH OF BRASSES. 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 1 INCH. ELONGATION IN 5 INCHES. SET. ELONGATION IN PER CENT. OF LENGTH. LOAD PER SQUARE INCH. 1 ELONGATION IN 5 INCHES. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds. Inch. Inch. Pounds. Inches. Inch. I,6oo 0.0010 0.02 30,000 1-2525 25-05 2,000 0.0020 O.04 30,400 1 . 3080 26.16 3,000 0.0040 O.08 30,600 At this point the fastenings of the 4,200 0.0065 O.X 3 measuring instruments became loose, in 5,000 0.0077 0.15 consequence of the drawing down of the 6,000 0.0106 0.21 square head of the sp lecimen. 7,000 0.0139 0.28 Continued the test wit! tout measuring elonga- 8,000 0.0175 0.35 tions, and the piece broke near the middle 120 0.0099 at 32,200 pounds per square inch. 9,000 0.0223 0-45 Total elongation as measured after breaking, 10,000 0 . 0290 O.58 1.52" = 30.40 per cent. 11,000 0.0424 O.85 Diameter of fractured section, 0.585". 12,000 120 0.0626 0.0610 1.25 Tenacity per square 32,200 pounds. inch, original section, 13.000 14.000 0.0895 0-1337 1.79 2.67 Tenacity per square inch, fractured section, 59,899 pounds. 16,000 0.2227 4-45 The following measurements 01 diameter of 120 0.2204 different portions of the specimen were 18.000 20.000 0.3253 0.4459 6 . 5 t 8.92 made after breaking A end. C end. Elongation increased in 1 2 m. to 0.4542. At fractured surface. . . ' 0.585" Elongation increased in 4 m. to 0.4575. % inch from fracture. . 0.705 0.698 100 0.4489 1 inch from fracture . . 0.698 22,000 0.5809 ' ' 11.62 2 inches from fracture 0.708 24.000 26.000 0.7183 0.8504 14-37 17.01 3 inches from fracture 0.710 0.720 bar no. 5 A. Composition. — Original mixture : Cu, 75 ; Zn, 25. Analysis : Cu, 77.84 ; Zn, 21.78. 800 0.0010 0.02 1,200 0.0020 0.04 2,000 0.0043 0.09 3,000 0.0073 0.15 4,000 0.0096 0.19 5,000 0.0125 0.25 6,000 0.0155 0.31 7,000 0.0206 ...... 0.41 8,000 0.0250 0.50 200 0.0143 0.64 9,000 0.03 1:9 10, 00c 0.0380 0.76 11,000 0.0469 0.94 12,000 0.0631 1.26 200 0.0600 13,000 0.0933 ;:s 7 14,000 0.1324 2.65 16,000 0.2326 4-65 200 0.2293 18,000 0.344° 6.88 20,000 0.4605 9.21 Elongation increased in 1 m. to 0.4713". Elongation increased in 2 m. to 0.4795". 22,000 0.5820 11.64 24.000 25.000 26.000 Tc 4,04° • 7053 o.7 6 55 15-31 Measuring apparatus slipped ; con- tinued test without measuring elongations. Broke f inch from A end. otal elongation, measured after breaking 1.80" = 36 per cent. Diameter of fractured section, 0.585". Tenacity per square inch, original section, 34,040 pounds. Tenacity per square inch, fractured section, 63,322 pounds. Diameters after breaking. Inch. At fracture 0.585 1 inch from fracture 0.672 2 inches from fracture 0.685 3 inches from fracture 0.694 4 inches from fracture 0.696 5 inches from fracture 0.705 39 ° MA TE RIALS OF ENGINEERING— NON-FERROUS METALS TABLE LXXIII. — Continued, \ BAR NO. 8 B. Composition.— Original mixture : Cu, 60; Zn, 40. Analysis: Cu, 59.19 ; Zn, 40.39. LOAD PER SQUARE INCH. ELONGATION IN 5 INCHES. SET. ELONGATION IN PER CENT. OF LENGTH. LOAD PER SQUARE INCH. ELONGATION OF 5 INCHES. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds. Inch. Inch. Pounds. Inch. Inch. 2,000 0.0016 0.03 28,000 0.2310 4.62 3,000 0.0040 O.08 200 0.2190 4,000 0.0063 0.13 30,000 0.2648 5 - 3 ° 5,200 0.0075 0.15 32,400 0.3235 6.47 6,000 0.0103 0.21 200 0.3062 7,000 0.0113 O.23 34,000 0.3850 7.70 8,000 0.0134 O.27 36,000 0.4526 9-05 200 0.0008 200 0-4373 9,000 0.0152 0.30 36,000 0 . 4860 9.72 10,000 0.0173 0-35 38,000 0.5700 II.40 11,000 0.0191 O.38 Measuring apparatus slipped. 12,000 0.0220 O.44 50,520 (Elongat n measured with calipers). 200 0.0075 51,380 Broke in middle. 13,000 0.0249 0.50 Total elongation, measured after breaking, 14,000 0.0296 0.59 1.48" = 29.6" per cent. 16,000 0.0406 O.81 Diameters of fractured section, o .672" and 200 0.0336 0.678" (elliptical). 18,000 0.0545 I.09 Diameter of piece i inch from fracture, 0,687". 20,000 0.0773 1-55 Tenacity per square inch original section, 200 0.0716 51,380 pounds. 22,000 O.IIOO 2.20 Tenacity per square inch fractured section. 24,000 0.1445 2.89 71,762 pounds. 200 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 0.05 200 0.1091 3,000 0.0038 0.08 28,000 O. II39 2.28 4,000 0.0056 0. 11 30,000 0. ia8q 2.98 200 0.00x6 32,000 0.1791 3-58 5,000 0.0072 0. 14 200 0.1712 6,000 0.0086 0.17 j 36,000 O . 3017 6.02 7,000 0.0102 0.20 40,000 0.4236 8.47 8,000 0.0115 0.23 200 0.4077 200 0.0027 44,000 0.6201 12. AO 9,000 0.0131 0.26 | 48,000 Measuring a pparatus slipped. 10,000 0.0137 0.27 53,660 Broke at shoulder, B end. 11,000 0.0152 0.3° Total elongation, measured after breaking. 12,000 0.0167 0.33 1.27 = 25.40 per cent. 200 0.0082 Diameter of fractured section, 0.675". 13,000 0.0182 0.36 Diameter of piece i inch from fracture, 0.680". 14,000 0.0200 0.40 I Diameter of piece 3 inches from fracture, 15,000 0.0217 °-43 0.680". 16,000 0.0240 0.48 1 Diameter of piece 4 inches from fracture, 200 0.0201 .... 1 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, 20,000 0.0364 0-73 I 0.710". 22,000 0.0460 0.92 Tenacity per square i inch, original section, 24,000 0.0614 1.23 53,660 pounds. 26,000 0.0832 1.66 Tenacity per square inch, fractured section, 28,000 0.1136 1.27 74,975 pounds. STRENGTH OF BRASSES. 39 7 TABLE LXXIV. RECORD OF TESTS BY COMPRESSIVE STRESS. Alloys of Copper and Zinc. Dimensions : Length = 2" (5.08 cm.) ; diameter = 0.625" ( I 5 cm.). BAR NO. 2. Composition.— Original mixture: Cu, 90 ; Zn, 10. Analysis: Cu. 9.56; Zn, 90.42. LOAD. COMPRES- SION. LOAD PER SQUARE INCH. COMPRESSION IN PER CENT. OF LENGTH. Pounds . 500 Inch . 0.002 Pounds . 1,630 O. IO 1,000 0.004 3,250 0.20 2,000 0.009 6,519 0.45 3,000 0.012 9,778 O.60 4,000 0.022 13,038 I. IO 5, ooo O.O46 16,297 2.30 6,000 O.083 I 9,557 4 -i 5 7,000 O.II9 22,816 5-95 8,000 O.I52 26,076 7.60 9,000 O.187 29,335 9-35 10,000 0.225 32,595 11.25 11,000 0.262 35,855 13.10 v LOAD. COMPRES- SION. LOAD PER SQUARE INCH. COMPRESSION IN PER CENT. OF LENGTH. Pounds . Inch . Pounds . 12,000 0.294 39, TI 4 14.70 13,000 o -334 42,373 16.70 14,000 0.372 45,633 18.60 15,000 0.408 48,892 20.40 16,000 0.442 52,152 22.10 17,000 0.482 55 , 4 ir 24. IQ 18,000 0.530 58,671 26.50 19,000 0.563 61,930 28.15 20,000 0.599 65,190 29-95 Removed piece slightly bent, surface very rough. 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 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 5,000 0.019 16,297 o -95 26,000 0.562 84,747 28.10 6,000 0.022 T 9, 557 1. 10 28,000 0.613 91,266 30.65 8,000 0.032 26,076 1.60 30,000 0.652 97,785 32.60 9,000 0.042 29,335 2.10 32,000 0.691 104,303 34-45 10,000 0.065 32,595 3-25 34,000 0-734 110,822 36.70 11,000 0.109 35,855 5-45 36,000 °-vi II 7 , 34 I 38.65 12,000 0.154 39, XI 4 7.70 38,000 0.828 123,860 41.40 13,000 0.203 4 2 ,373 10. 15 39,000 0.876 127,119 43.80 14,000 0.243 45,633 12.15 40,000 0.916 130,379 45 . 8 o 15,000 0.273 48,892 13.65 41,000 0.966 133,638 48.30 16,000 0.309 5 2 ,T 52 * 5-45 42,000 1. on 136,898 50.55 17,000 o -339 55 , 4 n t 6.95 43,000 1 .058 140,157 52.90 18,000 0.366 58,671 18.30 Resistance decreased to— 19,000 0-399 61,930 T 9-95 34,000 | 1. 150 | 110,822 57-50 20,000 0.424 65,190 21.20 Removed piece squeezed out of shape with a 21,000 0.451 68,449 22.55 diagonal crack on one side. 39S MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE LXXI V .—Continued. BAR NO. 9. Composition.— Original mixture : Cu, 55 ; Zn, 45. Analysis: Cu, 55.15 ; Zn, 44.44. LOAD. COMPRES- SION. LOAD PER SQUARE INCH. COMPRESSION IN PER CENT. OF LENGTH. LOAD. COMPRES- SION. LOAD PER SQUARE INCH. COMPRESSION IN PER CENT. OF LENGTH. Pounds . Inch . Pounds . Pounds . Inch . Pounds . 1,000 0.005 3.259 O.25 20,000 0.150 65,190 7 - 5 ° 2,000 0.008 6,519 O.40 22,000 0.173 7*1709 8.65 3,000 0.010 9.778 O.50 24,000 0.202 78,228 IO. IO 4,000 0.012 13, ° 3 8 0.00 26,000 0.227 84,747 I *. 35 5,000 0.014 16,297 0.70 28,000 0-253 91,266 12.65 6,000 0.016 * 9.557 O.80 30,000 0.280 97,785 14.00 7,000 0.019 22,816 0-95 32,000 0.299 104,303 * 4-95 8,000 0.023 26,076 1 . 15 34,000 o .335 110,822 i 6.75 9,000 0.026 29.335 1.30 36,000 0.362 II 7 , 34 I 18 10 10,000 0.032 32,595 I.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 T 5 * 30,379 20.75 13,000 0.061 42,373 3-°5 41,000 0.436 *33,638 21.80 14,000 0.075 45,633 3-75 41,500 o -452 135,268 22.60 15,000 0.087 48,892 4-35 42,000 1 136,898 16,000 0. 100 52,152 5.00 Broke suddenly, a small piece breaking off 17,000 0.113 55 , 4*1 5-65 from upper corner. 1 8, coo 0.125 58,671 6.25 Bent slightly. 19,000 0.138 61,930 6.90 i BAR NO. II. Composition.— Original mixture : Cu, 45 ; Zn, 55. Analysis: Cu, 47.56 ; Zn, 52.28. 1,000 0.002 3,259 0. 10 26,000 0. 102 84,747 5.10 2,000 0.007 6 , 5*9 0-35 28,000 0.115 91,266 5-75 3,000 0.010 9,778 0.50 30,000 0. 130 97,785 6.50 4,000 O.OII 13,038 0.55 32,000 0.147 104,393 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 1 * 7 , 34 * 9.40 7,000 0.016 22,816 0.80 37,000 0. 198 120,600 9.90 8,000 0.018 26,076 0.90 38,000 0.210 123,860 10.50 9,000 0.019 29,335 0-95 39 , 000 0.221 127,119 n.05 10,000 0.021 32,595 1.05 40,000 0.239 130,379 *i .95 12,000 0.028 39 ,* *4 1.40 41.000 0.253 133,638 12.65 14,006 0.037 45,633 1.85 41,500 0.267 135,268 13-35 16,000 0.046 52,152 2.30 42,000 0.272 136,898 1:3.60 18,000 0.056 Cn 00 ON ^4 2.80 42,500 138,528 Broke 20,000 0.066 65,190 3 - 3 ° lust as beam rose, 22,000 0.078 71,709 3.90 Fracture diagonally across the middle of the 24,000 0.090 78,228 4.50 specimen. STRENGTH OF BRASSES. 399 TABLE LXXV. RECORD OF TESTS BY TRANSVERSE STRESS. Alloys of copper and zinc. Dimensions : Length, l — 22" ; breadth, (2.54 cm.) ; depth, d = 1" (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. Pounds . Inch . Inch. 10 0.0042 20 0.0080 40 0.0124 9,030,560 80 0.0206 10,708,667 120 0.0296 11 , 349,217 160 0.0363 12,339,278 200 0.0449 12,469,814 3 0.0056 240 0.0544 12,350,618 280 0.0692 Beam sinks II, 327, 350 slowly. 320 0.0980 9,141,138 360 0.1695 6,074,807 400 0.3288 3,405,686 3 0.2445 400 0.3352 | LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. 420 440 460 Inches . 0.4414 0.5885 0.7520 Inches. 480 0.959° 5 °° 520 540 560 1 . 1763 1-3463 1.6163 1.86 1,189,949 580 2.22 600 620 2.62 .3.27 641,107 Bent down without Breaking load, P= 1 breaking. Bar removed. 620 pounds. Modulus of rupture, ^=- 3 S= 2 bd 2 21,193. bar no. 5. Composition.— Original mixture : Cu, 75 ; Zn, 25. Analysis ; Cu, 76.65 ; Zn, 23.28. zo 0.0024 44.0 0.4110 20 0.0066 TT 460 0.5396 4 ° 0.0111 io, 347 , 4 i 9 480 0.6989 80 0.0204 11,260,425 500 0.9489 1,513,020 120 0.0288 11,964,201 C20 1 . 10 160 0.02 KA. I2.Q78.II7 T - Q 2 200 JJT 0.0439 13,081,592 560 x • D* 1.62 3 0.0059 580 1.94 240 0.0514 13 , 407,355 600 2.28 755,634 280 0.0620 12,967,651 620 2.64 320 0.0772 Beam sinks 11,902,213 640 3-39 slowly. TO O TO 360 0.1094 9,448,876 Bent without breaking. Removed bar. 400 O.2010 5,714,246 Breaking load, P — 1 540 pounds. 1 3 400 0.2129 0.136 0 Jr>l Modulus of rupture, R = - — ■ = 2 bd 1 22,325. 400 MATERIALS OF ENGINEERING— NON-FERROUS METALS TABLE LX X V . — Continued. BAR NO. 6. Composition.— Original mixture : Cu, 70; Zn, 30. Analysis: Cu, 71.20; Zn, 28.54. LOAD. DEFLECTION. SET. Pounds. Inch. Inch. 10 .00067 20 O.OII4 40 0.0172 80 O.O256 120 O.O334 l6o 0.0406 200 0.0501 3 0.0052 24O O.0582 280 O.0680 320 O.0794 36° O.O957 Beam sinks 400 0.1268 3 0.0408 440 O.2147 480 O.4258 500 O.5396 MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. Inches. Inches. I C20 0.6832 CJO 0.8532 6,6 91,260 Jt 560 I . 1092 8, 99^379 580 I . 2972 10,337,393 I 10 1.1467 11,338,883 580 1.3462 11 ,485,995 600 1-55 1 , “3, 77i 620 1.80 11,864,913 640 2.15 11,847,464 660 2.45 u,595,933 680 2.80 10,823,479 1 700 3-30 610,324 9,076,471 j | Bent without breaking. Removed bar. Breaking load, P = 700 pounds. 1 2,660,088 Modulus of rupture, 1 p 3 PI ' 2 bd^ = = 24,468. bar no. 7. Composition.— Original mixture : Cu, 65 ; Zn, 35. Analysis : Cu, 66.27 ; Zn, 33.50. 10 20 40 80 120 160 200 3 240 280 320 360 400 3 440 480 520 560 600 0.0028 0.0058 0.0124 9,168,783 0.0233 0.0317 0.0384 9,759,049 10,759,827 11,843,014 0.0466 0.0033 12,198,812 0.0546 12,493,727 0.0642 12,396,423 0.0728 12,493,727 0.0836 12,239,668 0.0948 O.OIT2 11,992,925 O.IIIO Beam sinks 11,226,865 0.1454 0.2128 slowly. 6,914,525 0.4680 0-5958 2,862,360 3 620 640 660 680 700 720 740 760 780 Repeated. 780 800 820 0.6734 0.8436 1.0268 1.2058 1. 41 1 *59 1.79 2.04 2- 34 2.84 3- 34 3.84 5538 3-54 1,411,082 680,796 Bent without breaking. Bar removed. Breaking load. P = 820 pounds. Modulus of rupture, R = ^2? = 28,459. 2 ba * STRENGTH OF BRASSES. 401 TABLE LXXV. — Continued. BAR NO. 8. Composition. — Original mixture : Cu, 60 ; Zn, 40. Analysis : Cu, 60.94 ; Zn, 38.65. Pounds . 40 80 120 160 200 240 280 320 360 400 Inch . 0.0203 0.0291 0.0380 0.0447 °.°534 0.0626 0.0721 0.0820 0.0906 0.1000 Inch . o >: 2 3 5,488,205 7, 8 35,43 8 8,795,568 9,969,625 10,431,698 ;;;;;; 0.0135 10,678,327 10,816,556 10,869,170 11,067,272 II , I 4 I ,°54 Left under strain 18 hours ; deflection and re sistance to deflection unchanged. 10 0.0146 440 O.IIOI 480 0.1193 520 0.1290 560 0.1425 600 0.1585 10 0.0283 640 0.1747 720 0.2555 800 0.5021 10 0 . 3060 11,130,936 11,206,425 11,227,419 ro, 945, 596 io.543,5 8 5 10,203,600 7,848,884 4,437,7 8 4 fe O £ H Jfl u i-l H 13 Pounds . Inches . Inches . 800 0.5090 Resistance decreased in 1 hour to 782 pounds. ,3224 840 880 900 920 940 960 980 1,000 t,IOO 0.5275 0.9685 0. 9885 1.04 1 .26 1.33 I 53 1 . C2 2.67 2,535-900 719,298 to 1,026 pounds. Resistance decreased in 30 sec. Resistance decreased in 1 m. to 1,020 pounds. Resistance decreased in 17 hr. 30 m. to 990 pounds. 1,130 I 2.72 I I 1,140 | 2.75 | I Ran down pressure screw about 1 inch further; maximum resistance to rapid motion 1,160 pounds. Bent without breaking. Breaking load, P = 1,140 pounds. q P l Modulus of rupture, R — - — T — „ = 38,968. 2 bd z BAR NO. 9. Composition. — Original mixture: Cu, 55 ; Zn, 45. Analysis: Cu, 55.15 ; Zn, 44.44. 20 40 80 120 160 200 10 240 280 320 360 400 10 440 480 520 560 600 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 O. 1 1 10 0.1317 0.1496 0.1790 0.247 0.2645 0.3306 0.3951 o . 5060 0.5315 0.5833 0.8367 0.8581 0.0080 0.0213 0.1663 0.6250 7,888,340 8, 194*, 687 8,800,055 9,247,321 9,538,189 8,756,005 9,080,354 9,302,585 9,466,607 8,864,649 8,584,370 7,826,643 7,069,010 5,297,071 4,839,294 2,790,663 860 I .0364 880 I. 1250 900 1.1953 920 1.2722 940 1-3423 960 1.4647 2,197,622 Resistance decreased in 20 min. to 942 pounds. Resistance decreased in 16 hr. to 916 pounds. 2233 920 1.4785 94o 1. 5175 960 1.5900 980 1.6815 1,000 1.7675 1,653,646 1,020 i.86 ,ioo 2.24 1,433,283 [60 2.65 Crackling sound heard from bar. 1,180 I 2.79 | I 1,200 | Bar bent and supports slid out from under it. Breaking load, P = 1,200 pounds. 3 PI Modulus of rupture, R = = 42,463. 2 oa z 26 402 MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE LXXV. — Continued. BAR NO. IO. Composition.— Original mixture : Cu, 50 ; Zn, 50. Analysis : Cu, 49.66 ; Zn, 50.14. LOAD. DEFLEC- TION. SET. MODULUS OF ELASTICITY. Pounds. 20 Inch . 0 . 0065 Inch. 40 O.OIIO 10,711,665 80 0.0219 10,760,578 120 0.0330 10,711,665 160 0.0429 10,986,324 200 0 . 0509 11,574,491 A slight crackling sound was heard while the strain remained on the bar, the deflection being held constant. IO 0.0025 200 0.0509 Beam sinks slowly. 240 0.0623 280 0.0773 320 0.1009 360 °- 1 337 400 0.1736 IO 0.0816 440 0.2220 480 0.2752 520 0.3291 560 0.3909 600 0.4568 10 0.3165 640 0.5182 1 1, 347, 832 10,670,093 9*342,185 7, 93i,6oo 6 , 787,347 5,838,341 4,654,415 3,869,144 Pounds. 680 720 760 800 10 800 840 880 920 940 DEFLEC- TION. Inches. 0.5990 o. 6700 0.7647 0.6813 0.8713 0 9493 1.0613 1690 Inches. 0.6699 i! Isi 3 , i 65,537 2,704,656 2,318,265 On applying the stress several si ight cracks were heard, but there was no visible appearance of breaking. The resistance sud- denly decreased, and on balancing the scale beam was found to be 580 pounds. 580 i 1.2570 I I 10 I | 1.1195 I Applied stress again, and the resistance 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 held constant for several minutes. Breaking load, P = 940 pounds. Modulus of rupture, R bd 2 = 33,467- ALLOYS OF COPPER AND ZINC. BAR NO. 32. Resistance decreased in 22 hrs. to 751 pounds 3 75i 800 820 840 860 880 900 920 940 960 0-3364 0.3490 0.3583 0.3790 0.3948 0.4145 o.4343 0.4518 0.4669 0.4905 0.1638 6,283,536 980 1,000 1,020 1,040 1,080 1,100 0.5122 0.5302 0.5444 o- 57 j 8 0.6140 5,7i8,6 5,433,432 Broke in middle just as beam rose. Breaking load, P= 1,100 pounds. Modulus of rupture, R = - 7-35 = 40,189. 2 bd ^ 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. STRENGTH OF BRASSES. 403 TABLE. LXXV. — Continued. BAR NO. 33. Composition. — Original mixture: Cu, 42.5 ; Zn, 57.5. Analysis: Cu, 43.36; Zn, 56.22; Pb 0.38. LOAD. deflection. SET. modulus of ELASTICITY. Pounds . 10 20 Inch . 0.0030 0.0072 Inch . 40 0.0164 5,950,134 60 0.0279 5,246,355 120 °-°354 8,246,381 160 0.0421 9,271,468 200 0.0497 0.0063 9,817,123 3 240 0.0556 280 0.06x4 11,125,005 320 0.0672 11,616,928 LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds . 360 Inch . O'. 0724 Inch . 12,130,383 12,367,832 400 0.0789 3 O.QII5 44 ° 0.0850 12,628,285 480 0.0909 12,882,137 I 2 , 9 l 8 , 2 XX 520 0.0982 54 ° . Broke just as beam rose. Breaking load, P = 540 pounds. ? PI Modulus of rupture, R = — — - = 17,691. 2 bd z bar no. 39. Composition.— Original mixture: Cu, 12.5; Zn, 87.5. Analysis: Cu, 12.12; Zn, 86.67; Pb, 1.22. 10 20 40 80 120 160 200 3 240 280 320 360 400 3 440 480 520 560 0.0022 0.0056 0.0128 0.0234 0.0329 0.0430 0.0526 0.0641 0.0729 0.0818 0.0921 0.1016 0.1115 0.1216 0.1316 0.1421 8,982,413 9,826,913 10,484,031 10,695,338 10,929,173 O.OOII 10,762,079 11,040,112 11,244,489 Beam sinks Hr 235,332 slowly. 11,316,427 0.0064 11,342,857 11,346,204 1 1,359,423 11,327,574 600 3 11.286,725 0.0148 Resistance increased in 10 minutes to 10 pounds. 640 680 720 760 800 3 <840 880 920 960 1,000 Breaking load, P =- 1,000 pounds. 3 PI Modulus of rupture, R = — — = 35,026 2 bd i O.OII4 0.1663 0.1796 0.2006 0.2116 0.2261 0.0378 O.2450 0. 2624 0.2856 0.3124 Broke just as beam ro 11,061,926 10,882,925 I °i3 2 3i^3 I 9,854,99! 8,832,898 BAR NO. 41. Composition.— Original mixture : Cu, 2.5 ; Zn, 97.5. Analysis: Cu, 2.45 ; Zn, 96.43 ; Pb, 1.05. 20 0.0067 0.0154 40 8,117,624 80 0.0255 9,581,630 120 0.0362 10,124,235 160 0.0486 10,054,796 200 0.0618 9,883,964 3 0.0051 240 280 0.0764 0.0932 Beam sinks 9,175,542 slowly. 320 0.1124 8,695,074 360 0.1352 8,132,338 400 o.i6ox . ... 7,63°, 593 3 0.0498 440 480 520 560 600 3 600 630 0.1895 0.2225 0.2596 0.3137 0.395° 6,588,717 5,452,091 4,639,208 0.0270 0.4097 ...... Crack appeared in bottom of bar ; resistance decreased rapidly, and | bar broke. Breaking load, P = 630 pounds. o pi Modulus of rupture, R — — = 23,137. 2 bd 1 404 MATERIALS OF ENGINEERING— NON-FERROUS METALS. 237. The Method of Variation of Resistance with dis- tortion is illustrated by strain-diagrams, several of which, as obtained by tests in tension, are given in Figure 17. These strain-diagrams are produced, in this case, by plotting the record of test, making the ordinates of the curve proportional to the load and the abscissas variable with the extension. In Fig. 17.— Strain-diagrams of Brasses. LBS PER SO IN. TESTS BY TENSILE STRESS. preparing the test-pieces, the yellow alloys, Nos. 1 to 10, con- taining less than 0.55 zinc, were easily turned in the lathe. The white alloys, Nos. 12 to 15, 0.60 to 0.70 zinc, could not be turned as they were too brittle to be worked ; these were tested in the bar, unturned. The blue-gray alloys, Nos. 16 to 21, containing over 75 per cent, zinc, were more easily cut than the first class and were tested in standard form and size. STRENGTH OF BRASSES. 405 Studying these diagrams, it is seen that, in some cases, there appears the semblance of an elastic limit at not far from one-half the maximum resistance. This is most easily seen in the diagrams of Nos. 4 to 8. The tenacity varies enormously, as, for example, between Nos. 8 or 9 and 21. Fig. 18.— Strain-diagrams of Brasses. p ounc j s Tests By Transverse Stress Deflection‘in Inches The ductility is correspondingly variable, as illustrated by the same cases. The elastic resilience is evidently greatest with brittle alloys, as Nos. 11 A, 11 B; but the total re- silience, as measured by the area covered by the curves, is seen to be enormously greater in the strong and ductile alloys, of which Nos. 8 and 9 (Muntz metal) containing 40 and 45 per cent, zinc are examples. Nos. 8, 9 and 10, which con- tain from 40 to 50 per cent, zinc, are obviously by far the 406 materials of engineering— non-ferrous metals. best compositions for general use, and the next best class contains less zinc, as Nos. 4 to 7 (zinc, 20 to 35). 238. Strain-Diagrams obtained by Transverse Stress, Figure 18, are illustrative of the same facts as were exhibited by tests in tension. These are another set of bars similarly graded from copper, 100, to zinc, 100. Here again a Muntz metal, No. 30 (zinc, 40), is by far the best. Nos. 29 to 32, form a valuable group (zinc, 37.5 to 50), and the lower num- Fig. 19. — Comparison of Resistances. bers, containing less zinc, stand next in order. The smooth- ness of these curves is remarkable. No definite elastic limits are found here, although some alloys, as Nos. 22-28, present indications of one nearly as well defined as is sometimes the case with the best iron. 239. Comparisons of Resistances, as determined by the several methods of test, are made by plotting the curves of resistance side by side, as in Figure 19. No direct relation is known to exist among these variations of load and of distor- tion, but a close correspondence of general form is seen in the diagrams. The curves are so irregular that it is evident that further STRENGTH OF BRASSES. 40 7 investigation will be needed to ascertain their exact form, as determined by composition and unaltered by physical and accidental conditions. The positions of the maximum and the minimum are very nearly the same, as indicated by all forms of test, and may be taken, for practical purposes, as at zinc, 35 to 40, and at zinc, 60 to 65, respectively. All methods of test concur in showing that the valuable alloys for the ordinary work of the engineer lie on the copper side of the maximum, where alloys are found which are tough as well as strong. Those lying on the zinc side of the minimum, and near the composition, copper, 15 to 20, zinc, 85 to 80, may prove valuable as bearing metals and for castings or worked parts not required to be of great strength ; their malleability constitutes their prominent good quality. The curves of resistances to various kinds of stress show that they have a close relation depending upon the composi- tion, in a portion of the series, but exhibiting a very different law in other portions. The alloys between 17.5 and 32.5 per cent, zinc by origi- nal mixture, or between 16.98 and 30.06 per cent, zinc by analysis, show a remarkable similarity in all properties. They have all nearly the same strength, and nearly the same duc- tility, the latter decreasing slightly as the percentage of zinc increases. They are similar in color and appearance, so that one could scarcely be distinguished from the other. Their moduli of elasticity are nearly the same. The moduli of rupture by transverse stress in this group varied from 21,193 to 26,930 pounds per square inch (1,490 to 1,893 kilogs. per sq. cm.), these moduli being calculated from the loads which caused deflections of 3 y 2 inches (9 cm.), as all of the bars bent without breaking. The mean tensile strength of the two pieces from each bar varied from 28,120 to 35,630 pounds per square inch (1,977 to 2,505 kilogs. per sq. cm.), the lowest figure being exceptional, and the piece possibly slightly de- fective, as the next higher figure was 30,510 pounds (2,144 kilogs. per sq. in ). All bars which contained less than 15 per cent, zinc by mixture, or less than 11.06 per cent, zinc by analysis, were 408 materials of ENGINEERING— NON-FERROUS metals. defective, and their resistances were accordingly lower than would be observed with sound castings. A few pieces of this group gave higher results than the average, and these may be taken as probably nearly the results which would be given if the bars had been sound throughout. Between the compositions containing 32.5 and 37.5 per cent, zinc by mixture, or 30.06 and 36.36 per cent, zinc by analysis, occurs a rapid increase of strength. The latter alloy (63.44 copper, 36.36 zinc), had a modulus of rupture of 43,216 pounds (3,038 kilogs. on the sq. cm.), and a mean tenacity of 48,300 pounds per square inch (3,395 kilogs. per sq. cm.). Between the compositions containing 37.5 and 55 per cent, zinc by mixture, or 36.36 and 52.28 per cent, zinc by analysis, is another group of alloys, which contains that of maximum strength by transverse, tensile, and torsional tests, but not by compressive test, and higher than that of the first group. The moduli of rupture vary from 33,467 to 63,304 pounds (2,353 to 4,450 kilogs. per sq. cm.), the mean tenacity from two-thirds to four-fifths as much. The figures decrease as the proportion of zinc increases beyond that which is con- tained in the alloy of maximum strength (58.49 copper, 41.10 zinc). The curves of test indicate that this composition is nearly that of maximum strength, and probably within 2 per cent, of the actual maximum. The alloy of maximum strength contains about 41 per cent, of zinc. The compressive strength of this group bears no relation to tensile, transverse, or torsional strength, as it increases regularly with the increase of zinc ; and the maximum compressive strength of all alloys of copper and zinc is probably reached at an alloy containing more than 55 per cent of zinc. The ductility of this group has no relation to strength, and always decreases as the proportion of zinc increases. The alloys containing less than 55 per cent, of zinc by mixture (52.28 zinc by analysis), are the yellow metals or use- ful alloys. Between the compositions containing 55 and 60 per cent, zinc by mixture (or 52.28 and 58.12 zinc by analysis) there is STRENGTH OF BRASSES. 409 a rapid decrease of strength as well as a rapid decrease of ductility. Between the compositions containing 60 and 70 per cent, zinc by mixture (or 58.12 and 66.23 P er cent, by analysis) there is some uniformity of strength, these being the second class, silver-white, brittle alloys. The moduli of rupture of this group, and the tenacity are low. Between the compositions containing 70 per cent, zinc by mixture and pure zinc, comprising the bluish-gray alloys, the curves of resistances gradually fall. 240. Resilience. — The resilience of pieces containing less than 15 per cent, of zinc are uncertain in consequence of their being defective. Two torsion pieces within this limit give the maximum resiliences of 896.69 and 881.59 foot-pounds, these pieces being also the most ductile under torsional test. From the latter of these figures there is a rapid and comparatively regular decrease of total resilience by torsion to alloy 38.46 copper, 61.05 zinc, only about 2370-0 oth of the maximum. The resiliences by transverse test, on the contrary, increase from the defective bars to the bar of maximum strength, 58.49 cop- per, 41.10 zinc, with considerable regularity, as the strength increases, and then as the bars become of such low ductility as to break, the resilience decreases, and the curve takes nearly the same form as the curve of torsional resilience to the end of the series. From alloy 41.30 copper, 58.12 zinc, to 14.19 copper, 85.10 zinc, the resiliences are small, corresponding with the combi- nation of low strength and low ductility. At alloy 7.20 cop- per, 92.07 zinc, there is a second maximum of resilience, the very large increase of strength of the alloy over those of mini- mum strength contributing to give this alloy more resilience than cast zinc, although the latter has much the greater duc- tility. 241. Limit of Elasticity. — In the table of results of tests, figures are given representing the transverse load at the ap- The relation between the elastic limit and ultimate strength 410 MA TE RIALS OF ENGINEERING— NON-FERRO U S ME TALS, appears to vary considerably. The percentage ratios by trans- verse tests appear to be greater than those by the other methods of test. In the more ductile alloys, containing less than 50 per cent, of zinc, the elastic limit is generally from 20 to 50 per cent, of the ultimate strength ; as the percentage of zinc in- creases beyond 50 per cent., and the alloys become more brittle, F IG . 20.— Moduli of Elasticity and Specific Gravity. (From Transverse Tesls) 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 ioo 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. STRENGTH OF TRASSES. 411 242. 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 minimum 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 and 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. 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 2.501 1 (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 zinc there is a very regular decrease of ductility, the latter having an extension of 0.00002, or only about TsT/oro-th 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 0.0001 1. 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. When brasses are desired to work freely, as with auto- matic machinery, one or two per cent, of lead should be added ; giving freedom of working and ease in cutting such as cannot be attained otherwise. Such compositions are called “leaded brass.” Bismuth in brasses causes hot- and cold-shortness, fire- cracks, and general deterioration. 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, Aes.). 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, lbs. per square inch. 60,020 46,060 43,120 54.220 52,080 62,720 70,806 72,845 76,160 84,920 60,480 76,160 84,920 62,720 73,680 82,880 Kilogs. per square cm. Ultimate elongation at breaking point in inches. 4,213 3,386 3,032 3,819 3,662 4,410 4,978 5,121 5,355 5,935 Treatment. .1 •05 .015 .016 .02 .045 as received. cast in sand. cast in iron, cast in iron annealed, forged red hot. cast in iron and forged red hot. and 1 Mixture. Austrian. Copper, 60 ; zinc, 39 ; iron, 3 ; tin, 1.5. Copper, 60 ; zinc, 44 ; iron, 4 ; tin, 2. Copper, 60 ; zinc, 37 ; iron, 2 ; tin, 1. Copper, 60 ; zinc, 35 ; iron, 3 ; tin, 2. 4,252 5,355 5,985 4,4io 5,040 5,827 after simple fusion. forged red hot. drawn cold, after simple fusion. forged red hot. drawn cold and reduced from 100 to 77 trans- verse sectional [ area. _ I I Copper, 55.04 ; spelter, 42.36 ; iron, 1.77 ; tin .83. I Copper, 57.63; spelter, - 40.22; iron, 1.86; tin, 0.15. * “ 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, voh xxvi. Trans. Am. Soc. C. E., 1881. Also, for later work, by A. Wright, Proc. Roy. Soc,, 1891-4. STRENGTH OF KALCHOIDS. 417 example, C E. From any point within the triangle, A , let fall perpendiculars A G , A H, A Fj and draw A B, A C, A D to H the vertices, thus obtaining three triangles, ADD, ABC , A C D; their sum is equal 0 to the area of the whole figure BCD . Now we have, since the triangle is equilateral, and C E x B D _ A F x B D AGxBC AHxCD ■ ~ ~ 2 + ~ ~ v CE x B~D = (A~E + A~G + All) x BD\ and HE = ACE + AAS + Al 7 \ 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 + A H + A G = 100 and ^ d.—, 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 C D = 100 per cent. = (A F + A G + A H) B D, or CE = 100 per cent. = A F + A G + AH 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 BCD , and 27 41 8 MATERIALS OF ENGINEERING— NON-FERROUS METALS \ every point represents and identifies a single alloy, and only that. The vertices B y C , D, in the case to be here con- sidered, represent respectively, copper = ioo, tin = ioo, zinc = ioo.* 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 : Y * The same general principle may be employed, as stated in the discussion before the Am. Assoc, for Advancement of Science (Nashville meeting, 1877), where four variables are studied. It has been so employed by Professor Howe (Trans. A. I. M. E., Feb. 1898, vol. xxviii, pp. 346, 894: “Use of Tri-axial Diagram and Triangular Pyramid”). Professor J. Willard Gibbs proposed the use of the principle in still another field in 1876 (Trans. Conn. Acad., 1876, p. 108). It is in constant use in the laboratories of Cornell University. STRENGTH OF KALCHOIDS. 4*9 TABLE LXXVII. SCHEDULE OF COPPER-TIN-ZINC ALLOYS TESTED. COPPER. ZINC. TIN. COPPER. ZINC. TIN. IO IO 80 30 40 30 IO 20 70 30 50 20 IO 30 60 30 60 IO IO 40 50 40 IO 50 IO 50 40 40 20 40 IO 60 3° 40 30 30 IO 70 20 40 40 20 IO 80 10 40 50 IO 20 IO 70 50 IO 40 20 20 60 50 20 30 20 30 50 50 30 20 20 40 40 50 40 IO 20 50 30 60 IO 30 20 60 20 60 20 20 20 70 TO 60 30 IO 30 IO 60 70 IO 20 30 20 50 70 20 IO 30 30 40 80 IO IO 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 1 1,500,000 (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 percent. 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, copper 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 422 MATERIALS OF ENGINEERING— NON-FERROUS METALS. 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 for a 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 per cent, 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. 1 (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 15, Zn 2.5). The difference in ductility between the two ends of the bars 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 0 , while the lower end, B, broke after it was turned through 7.5 0 , 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. 1 (Cu 60, Sn 2.5, Zn 37.5), had a mean maxi- mum torsional moment of 216 foot-pounds (tenacity about 40,000 lbs. or 2,892 kilogs.), and the weakest, No. 7 (Cu 72.5, Sn 10, Zn 17.5), 122 foot-pounds (tenacity about 24,000 lbs., 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 41 8.4° ; 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. 1, 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. V* STRENGTH OF KALCHOIDS. ^5 252. 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 1 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. 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. 25 3. General Deductions. — The remarkable variations of quality here so strikingly shown attracted attention, and a further investigation was made. These alloys were purposelv 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 the strongest bronze that the engineer can make of these metals. The “ naval bronzes ” now usually approximate this composition. 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' 1 was intended to be made in an independent and later research, in which chemically pure metals, more carefully handled, and STRENGTH OF HAL CHOIRS. 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 had a 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 y is superior to that of the gun-bronze, and the elastic range is seen to be greater, on 430 MA TERIALS OF ENGINEERING— NON-FERRO US ME TALS. 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 e , 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 to 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 Fig. 26.— Strain-diagrams of Bronzes. STRENGTH OF KALCHOIDS. 431 43 2 MATERIALS OF ENGINEERING— NON-FERROUS METALS made in the course of every-day business in the foundry, should be about — T c = 30,000 + 1,000 t ; where t is the percentage of tin, and not above 15 per cent. Thus gun-bronze can be given about 30,000 4- (1,000 x 10) = 40,000 pounds per square inch, if well made. In metric measures = 2,109 + 70-3 A giving for good gun-metal 2,109 x 7° 3 = 2,812 kilogs. per sq. cm. For brass (copper and zinc) the tenacity may be taken as T z — 30,000 + 500 z , where the zinc is not above 50 per cent.; and 7 ; 1 = 2,109 + 35.15 z. Thus copper 70, zinc 30, should have a strength of 30,000 4 (500 x 30) = 45,000 pounds per square inch, or 2,109 + (35*i5 x 3°) = 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 + 3 t — Constant = 55, in which z is the percentage of zinc, and t that of tin. Thus a maximum is found at about t = o y z = 5^» 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 8 . TJ = 2,812 + 35.15 8 . Thus the alloy z = 1, 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 1) = 40,500 lbs. per sq. in. T l m = 2,812 + (35.15 x 1) — 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 lbs. per sq. in. T l m = 2,812 4- (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 4- (500 x 50) = 65,000 lbs. 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 1 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 0 0 30,000 2,109 95 5 0 32,500 2,285 90 10 0 35,ooo 2,460 85 15 0 37,5oo 2,636 90 0 10 40,000 2,812 95 0 5 35,ooo 2,460 97i 0 2 \ 32,500 2,285 9 ° 5 5 37,500 2,636 85 10 5 40,000 2,812 75 20 5 45,ooo 3,163 68 30 2 47,000 3,304 64 35 1 48,500 3 ’ 4 IQ 60 40 0 50,000 3,5i5 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 27 , 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 1 + 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 HAL CHOWS. 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. — Tenacity of Copper-Tin-Zinc Alloys. on the map by a slightly curved dotted line to which a line having the equation 2.5/ + 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 ^ MATERIALS OF ENGINEERING— NON-FERROUS METALS Above this line is another having nearly the equation 4/ + % = 50, which last line is that of equal ductility for alloys exhibiting extensions of 3 percent. Still nearer the “pure copper corner ” is a line fairly representing alloys containing about 3 y^t + 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 1 + z — 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^ + ^=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 1 + 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 theif 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 0 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 and 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 Chimie, 1850. 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. 100 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 + 1,000/ + 500 z> T\ m n =4,218 f 7O.3/ + 35.I5S, 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. 440 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 [884.* 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 KAL C HO ID S. 441 composition, making 46 test-pieces. U sually, 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. ZN. SN. NO. CU. ZN. SN. I 55 43 2 9 53 43 4 17 58 40 2 2 54 44 2 10 55 4i 4 18 5-1 45 I 3 54 43 3 II 57 4i 2 T9 53 44 3 4 55 42 3 12 57 43 0 20 54 42 4 5 56 42 2 13 55 45 0 21 5'> 4i 3 6 56 43 1 14 52 46 2 22 57 42 1 7 55 44 1 15 52 43 5 23 58 4i 1 8 53 45 1 !6 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 442 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 — wh -f f; where w — moment necessary to deflect the pencil one inch ; h — height of the curve above the base line at; 0 rf f — friction in foot-pounds, and M is the total torsional moment. In this case, w — 96.93 foot-pounds, and f — 4.75, h being measured on the strain-diagram of each test-piece. To obtain the required values of T the formula T = [300 — Af,* in which M is known, and 0 r is measured directly from the autographic record ; T is the calculated tenacity. The values of M, T, 0 e and 0 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 AI.LOYS OR KALCHOIDS. ORIGINAL MARK. STRESS IN TORSION. FOOT-POUNDS. M. APPROXIMATE STRESS IN TENSION. FOOT-POUNDS. ANGLES. Ultimate. ! Average. Ultimate. Average. Oe e r IXI ^ OB ^ Z 3 i J 4 b 270.208 251.922 178.321 j 208.400 I 251.922 219 935 24 L 39 2 258.319 261.065 193.369 ! 235.929 250.851 77,309 72,301 53,946 59,810 75,576 65,980 73,017 74 , 9 12 74,305 56,653 70,778 73,965 T - 5 ° 1 1. 1 0.7 1 1 2 2 43 ° 40 5-05 40 13-77 10 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 K A L CH 0 ID S . 44 3 TABLE LXXX. — Continued . ORIGINAL MARK. STRESS IN TORSION. FOOT-POUNDS. M . APPROXIMATE STRESS IN TENSION. LBS. PER SQ. IN. T . Ultimate. Average. Ultimate. Average. F 5 A B 268.881 263.543 266.212 75,824 75,109 75,467 G 6 A B 227.689 220.612 224. 151 64,208 63 U 93 63,700 K 7 A B 286.847 250.855 268.851 80,910 70,741 75,826 R 8 A B 194.634 I 84 - 33 I 189.488 58,390 55,299 56,844 S 9 A B 222.853 230.597 226.725 66,853 69 U 79 68,017 L 10 A B 249.014 252.881 250.948 74,704 75,864 75,284 Z 11 A B 260.645 237.382 249.014 74,269 63,964 69,116 D B A B 227.689 241.259 234-474 61,020 61,762 61,390 M 13 A B 227.689 208 . 303 217.996 64,208 57,908 61,058 U 14 A B 163.715 I 77 -I 85 170.450 49 ,ii 3 53 U 55 5 UI 39 V 15 A B 189.886 227.689 208.788 56,965 68,306 62,636 N 16 A B 225.750 253.198 239.974 67.725 75,959 71,842 A 17 A B 227.689 250.952 238.771 63,200 73,488 68,344 P 18 A B 254-829 260.645 259-737 72,871 7 U 50 I 72,186 T 19 A B 231.566 196.671 214. 119 69,459 59 , 00 ! 64,230 Q B O A B 229.628 258.707 244.168 68,888 77,612 73,250 H B I A B 283.908 229 628 266.768 81,381 68,888 75 U 35 E B B A B 305-233 221.773 263.508 85,770 60,986 73,378 B 33 A B 225.750 175.247 200 . 499 63,084 45,038 54,061 ANGLES. Oe Or 4.6° 55 ° 2 46 2.05 53-3 2 42-1 2 54 2 53 2 9.1 2.69 5-72 i -5 5-78 1.79 4-5 2.1 4.6 2.8 8.8 2.4 39-8 1.9 35 2-3 95-2 1.6 I 3 I -4 2 52-4 1. 1 65 2-3 4.9 2 7.2 2.6 4 2 5 1.6 3-8 1.6 6.8 1.4 54 1.8 43-2 1.6 43-4 1.8 54 2.2 8 1.4 4.8 1.6 6.4 1.8 7.2 2-9 38 2.4 8 2 56 2.5 76 1 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 re‘spects similar to No. 7, and exceedingly tough. It was found that, when the average values of M 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. 1 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. 1 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. 18 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 0 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 KALCH OIDS. 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. io, 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 6 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 6 r being 11.9 0 . 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. 1 7, was a very ductile alloy, its values for 0 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, w r as 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 6 r being 1 13. 3 0 . 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 446 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, 1 ; 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 y 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 13F2 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., a Muntz metal, containing from a fraction of 1 per cent, to sometimes 2 per cent, of tin, as well as some iron. 44 8 materials of engineering— non-ferrous metals. The bronze used for journal bearings in the U. S. Navy contains copper, 88; tin, io; 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. * This kalchoid composition has been prescribed by the U. S. Ordnance Bureau for gun-carriages and also Cu 55, Zn 44.5, Sn 0.5 ; the latter having a mean tenacity of 50,000 to 60,000 and a maximum of 64,000 pounds per square inch. — -Reports, 1898. 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— NuN- &ERR0 US 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 t + 7,000 z , ) T m = 316 t + 492 z, j (16) 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, | C m = 422 t + 1,406 z f j The Modulus of Rupture maybe taken for tin-zinc com- positions, at R = 3,500 t + 7.500 z, ) R m = 246 t + 527 *, f { J 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 * + 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 ALIO YS. 45 1 proportion of zinc, the tensile strength becoming insignificant when the proportions are such that, approximately, z + 2 t = 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 (21 1, 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, 1, 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, 2y£. 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 MA TEA r ALS OF ENGINEERING— NON-FERROUS METALS. Various alloys examined by Muschenbroek,* who was the only phys ; *:ist, 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. TENA Lbs. per sq. in. CITY. Kilogs. per sq. cm. S. G. Gold, 66.7 Silver, 33 - 3 - • • • 28,000 1,968 “ 83-3 Copper, 4 4 16.7 50,000 3,515 Silver, 83-3 16.7. . . . 49,000 3,445 “ 80.0 Tin, 20.0. . . . 41,000 2,882 Tin (Eng.), ii it 90.9 Lead, 9.1.... 7,000 492 88.9 44 11 . 1. . . . 8,000 562 «< 44 85-7 14.3.... 8,000 562 4 4 4 4 80.0 4 4 20.0. . . . 11,000 773 4 4 4 4 66.7 44 33-3 7,000 492 4 4 4 4 50.0 44 50.0 7,000 49 2 Tin (Banca), 4 4 4 4 90.9 Antimony, 4 4 9.1. . . 11,000 773 7-36 88 . 9 11 . 1 ... . 10,000 703 7.28 4 4 4 4 85.7 4 4 14 - 3 - • • • 13,000 914 7-23 4 4 4 4 80.0 44 20.0. . . . 13,000 914 7.19 4 4 4 4 66.7 44 33-3 12,000 874 7. 11 4 4 4 4 50.0 44 50.0. . . . 3,000 211 7.06 Tin (Banca), 90.9 Bismuth, 9.1. . .. 13,000 914 7-58 80.0 “ 20.0. . . . 8,000 562 7.61 “ “ 66 7 “ 33 - 0 . . . . 14,000 984 8.08 4 4 4 4 50.0 44 50.0. . . . 12,000 . 844 8.15 4 4 4 4 33-3 44 66.7. . . . 10,000 703 8.58 4 4 4 4 20 0 44 80 0 . . . 8,000 562 9.01 4 4 4 4 9.1 44 90.9. . . . 4,000 281 9.44 Lead, 50.0 Bismuth, 50.0. . . . 7,000 492 10.93 66.7 4 4 33 - 3 - 6,000 422 11.09 9.1 9°-9 3,000 211 1 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. STRENGTH OF COPPER-ZINC-TIN ALLOYS. 453 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 — in which M, b, d , are the bending moment, the breadth and the depth of the bar. When the material is ductile, R, — and, there- bd 2 fore, R — § R 1 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,;}; 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). X Part II., p. 491. 454 MATERIALS OF ENGINEERING— NON-FERROUS METALS ; TABLE LXXXII. TESTS BY TENSILE STRESS. ALLOYS OF COPPER, TIN, AND ZINC. Dimensions.— L ength = 5" (12.7 cm.); diameter = .798" (2 cm.). BAR NO. X B-D. Composition. — Original mixture : Cu, 70 ; Sn, 8.75 ; Zn, 20.25. LOAD PER SQUARE INCH. ELONGATION. SET. ELONGATION IN PER CENT. OF LENGTH. LOAD PER SQUARE INCH. ELONGATION. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds. Inch. Inch. Pounds. Inch. Inch. 1,400 .OOOI .002 16,000 .0046 .092 1,600 .OOOI .002 18,000 .0052 .104 1,800 .0002 .004 20, coo .0061 .122 2,000 .0002 .004 3 0 .0001 .002 2,500 .0003 .006 10,000 .0010 .020 3, ooo .0004 .008 20,000 .0053 .106 3^5°° .0005 .0X0 22,000 .0064 .128 4,000 .0007 .014 24,000 .0084 .168 5,000 .0009 .Ol8 28,000 .0142 .284 6,000 .0012 .024 32,000 .0217 •434 7,000 .0014 .028 36,000 .0316 .632 8,000 .0016 .032 Broke. 9,000 .0022 .044 Tenacity per square inch, original section, 10,000 .OO24 .048 36,000 | pounds (2,531 kilogs. per sq. cm.). 11,000 .0028 .056 Tenacity per square inch, fractured section, 12,000 .OO3I .062 36,080 pounds (2,536 kilogs. per sq. cm.). 13,000 OO35 .070 Diameter of fractured section, 0.797" (2 cm.). 14,000 .OO38 .076 BAR NO. 5 B-B. Composition. — Original mixture: Cu, 88.135 ; Sn, 1.865 \ Zn, to. 3,200 .0014 •°35 7,000 .0040 . 100 4,000 .0018 •°45 8,000 .0042 .105 4i5°° .0020 .050 9,000 .0044 .110 5,000 .0023 .057 10,000 .0050 .125 5,5oo .0026 .065 11,000 .0054 • T 35 6,000 .0028 .070 12,000 .0058 ..145 7,000 •0033 .082 13,000 .0088 .220 8,000 .0036 .090 14,000 .0121 .302 9,000 .0039 • °97 15,000 .0161 .402 10,000 .0043 .107 16,000 .0252 .630 11,000 .0047 .■1x7 18,000 .0548 1-370 12,000 .0052 .130 20,000 00 O' 0 2.460 300 .0008 22,000 .1595 3-987 100 .0011 .027 26,000 .3118 7-795 x ,400 .0013 .032 30,000 • 5 T 77 12.942 1 ,800 .0015 •037 33,000 .7818 19-545 2,200 .0017 .042 Broke. 2,600 .0019 .047 Tenacity per square inch, original section. 3,000 .0022 .055 33,000 pounds (21.30 kgs. per sq. cm.). 4,000 .0028 .070 Tenacity per square inch, fractured section. 5,000 .0033 .082 47,649 pounds (33.52 kgs. per sq. cm.). 6,000 .OO37 .092 Diameter of fractured section, 0.664' ' (1.7 cm.). STRENGTH OF COPPER-ZINC-TIN ALLOYS. 455 TABLE LXXXII .—Continued. BAR NO. 7 B-D. Composition. — Original mixture: Cu, 66.885; Sn, 1.865; Zn, 31-25. LOAD PER SQUARE INCH. ELONGATION. SET. ELONGATION IN PER CENT. OF LENGTH. LOAD PER SQUARE INCH. ELONGATION. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds . Inch . Inch . j Pounds . Inch . Inch . 3 °° 6,000 ' .0029 .058 1,000 .0002 .004 8,000 .0033 .066 2,000 .0004 .008 10,000 .6042 .084 3, ooo .0006 .012 12,000 .0055 .IIO 4,000 .0008 .Ol6 14,000 .0069 .138 4,200 .0008 .Ol6 16,000 .0089 .178 4,400 .0009 .Ol8 18,000 .0113 .226 4,600 .OOIO .020 20,000 .0209 .418 5,000 .OOII .022 22,000 .0309 .618 5 1400 .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 .0022 .044 32,000 .1391 2.782 11,000 .0029 .058 34,000 .1171 2.342 12,000 .OO36 .072 36,000 .2181 4.362 14,000 .0050 .IOO 36,540 Broke. 15,000 .0060 .120 Tenacity per square inch, original section, 16,000 .OO7O .140 36,540 pounds (24.68 kgs. per sq. cm.). 17,000 .0082 .164 Tenacity r per square inch, fractured section, 300 0016 1 -032 41,028 pounds (28.84 kgs. per sq. cm.). 2,000 .0020 .040 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. 300 | 30,000 .0240 .48 1,000 .0012 .024 32,000 .0254 .508 2,000 .0022 .044 34,000 .0268 .536 2,200 .0024 .048 36,000 .0282 • 564 2,400 .0026 .052 38,000 .0297 • 594 2,600 .0028 .056 40,000 .0313 .626 2,800 .0030 .060 300 .0150 .030 3,000 .0032 .064 10,000 .0215 • 43 ° 3,200 .0034 .068 1 20,000 .0279 •558 3.400 .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 48,000 .0494 .988 7,000 .0074 .148 50,000 .0527 1.054 8,000 .0081 .162 52,000 .0568 1.136 9,000 .0098 .176 54,000 .0615 1.23 10,000 .0085 .190 56,000 .0674 1.348 300 .0022 .044 58,000 .0771 1.542 10,000 .0113 .226 60,000 .0873 1.746 12,000 .0125 -25 62,000 .0958 1.916 14,000 •oi 37 .274 64,000 .1277 2-554 16,000 .0150 •30 66,000 •1577 3-154 18,000 .0165 •33 67,000 1 Broke. 20,000 .0176 • 35 ? Tenacity per square inch, original section, 22,000 .0189 •378 67,600 pounds (47.52 kgs. per sq. cm.). 24,000 .0202 .404 Tenacity per square inch, fractured section, 26,000 .0213 .426 73,160 pounds (5143 kgs. per sq. cm.). 28,000 .0226 •452 Diameter fractured section, 0.767" 1 :i-9 cm.). 456 MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE LX XX 1 1 . — Continued. BAR NO. 40 B. Composition.— Original mixture : Cu, 50; Sn, 5; Zn, 45. ! LOAD PER SQUARE INCH. ELONGATION. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds. Inch. Inch. 300 1,000 .0009 .018 | 2,000 .0018 .036 2,500 .0022 .044 3,000 .0025 .050 3 , 5 oo .0028 .056 4,000 .0022 .064 300 .OOOO 1,000 .0009 4,000 .0032 .064 6,000 .0051 .102 8,000 .0069 .138 10,000 .0087 .174 300 .0002 1,000 .OOII 10,000 .OO92 .186 12,000 .0107 .214 LOAD PER SQUARE INCH. ELONGATION. SET. ELONGATION IN PER CENT. OF LENGTH. Pounds. Inch. Inch. 14,000 .0126 .252 16,000 .0141 .282 18,000 • oi 55 .310 20,000 .0169 •338 300 .0005 1,000 .0013 22,000 .0184 '.368 24,000 .0195 ■390 26,000 .0205 .410 28,000 .0215 • 43 ° 30,000 3*,300 Broke. .0225 .450 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 section, 0.798" (2 cm.). bar no. 52 B. Composition.— Original mixture : Cu, 60 ; Sn, 5 ; Zn, 35. 300 1.000 2.000 2.500 3.000 3.500 4.000 300 1.000 4.000 6.000 8.000 10,000 300 10.000 12.000 14.000 16.000 18.000 20.000 0006 0018 0023 0026 0030 0033 0027 0035 0046 0054 0019 0058 0068 0076 0083 0090 .00005 .0006 .0001 300 .0007 .012 20,000 .0092 .036 22,000 .0098 .046 24,000 .0105 .052 26,000 .0114 .060 28,000 .0125 .066 30,000 .0138 3OO .0026 30,000 .0144 32,000 •0153 .O7O 34,000 .0165 .092 36,000 .0182 .108 38,000 .0x99 ..... 38,330 Broke. 'enacity per square inch, original 38,300 pounds (26.95 kgs. per sq. cm Tenacity per square inch, fractured 38,534 pounds (24.84 kgs. per sq. cm Di imeter of fractured section, 0.797" .184 .196 .210 .228 .250 .276 .306 •330 .364 •398 section, section, (2 cm.) STRENGTH OF COPPER-ZINC-TIN ALLOYS. 457 TABLE LXXXII. — Continued. BAR NO. 59 A. Composition.— Original mixture : Cu, 70 ; Sn, 5 ; Zn, 25. LOAD PKIi SQUAifE INCH. ELONGATION. SET. 2 ~ c % < (j 2 g | Pounds. 300 Inch. Inch. 1,000 .0004 ".oc8 2,000 .0009 .018 2,5°° .0012 .024 3,000 .0014 .028 3,5°° .0016 .032 4,000 .0018 .036 300 .0000 1,000 .0004 4,000 .0018 6,000 .0023 1 .046 8,000 .0029 i .058 10,000 .0036 .072 300 .0002 10,000 .0038 12,000 .0046 j .092 14,000 .0059 .118 16,000 .0079 j -158 18,000 .0098 1 .196 20,000 .0129 | -258 < I/D Jl w z < 2 < 2 SET. 2 b 0 i H s 5 < 5 2 g § Pounds. ' 300 ! Inch. Inch . .0004 20,000 •oi33 22,000 .0171 • 342 24,000 .0233 .466 26,000 .0296 .596 28,000 .0376 .752 30,000 .0472 •944 300 .0078 30,000 .0470 32,000 .0517 1.034 34,000 .0684 1.368 36,000 .0838 1.676 38,000 . 1028 ? 1 2.056 Broke just after reading was taken. Tenacity per square inch, original section, 38.00 3 pounds (26.61 kgs. per sq. cm.). Tenacity per square inch, fractured section, _39,oi4."pounds (27.43 kgs. per sq. cm.). Diameter of fractured section, 0.788" (2 cm.). BAR NO. 67 A. Composition.— Original mixture : Cu, 80 ; Sn, 5 ; Zn, 15. 300 1.000 2.000 .0012 .OO27 .024 .054 j 20,000 300 20,000 .0632 .0638 .0518 1.264 2,500 .OO36 .O72 j 22,000 .0847 1.694 3,000 .OO44 .088 24,000 .1150 2.300 3,500 .OO5O .IOO 26,000 .1582 3.164 4,000 .OO56 .112 28,000 .2650 4. IOC 300 .0003 30,000 .2642 5.284 4,000 .OO59 300 .2502 5.004 5,000 .0069 ^38 30,000 .2682 5.364 6,000 .0081 .162 32,000 .3422 6.844 8,000 .OIII .222 34,000 .4127 8.254 10,000 .OI5O .300 36,000 .5022 10.044 300 1,000 .OO38 .0052 37oOO Broke. .5804 11.608 10,000 •0157 •396 Tenacity per square inch, original section, 12,000 .OI98 37,560 pounds (26.40 kgs. per sq. cm. (. 14,000 I .O27I .542 Tenacitv per square inch, fractured section, 16,000 .0346 .692 48,005 pounds 134.38 kg's, per sq. cm.). 18,000 .0469 •938 Diameter of fractured section, 0.700' '(1.78 cm.). 458 MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE LXXXII. —Continued. BAR NO. 73 A. Composition.— Original mixture: Cu, 55; Sn, 0.5; Zn, 44.3. LOAD PER SQUARE INCH. ELONGATION AND SET IN INCHES. ELONGATION AND SET IN PER CENT. OF LENGTH. i MODULUS OF ELAS- TICITY. LOAD PER SQUARE INCH. ELONGATION AND SET IN INCHES. ELONGATION AND SET IN PER CENT. OF LENGTH. MODULUS OF ELAS- TICITY. Pounds. 300 1,000 Inch. .OOO25 .005 Pounds. 36.000 38.000 Inch. • 0473 .0586 .946 1. 172 2,673,796 2,000 .00065 .013 15 , 383,076 40,000 .0748 1.496 3,000 .OOII .022 13,636,363 300 Set .05535 Set 1. 107 4,000 .OO155 ..031 12,903,258 12,820,512 40,000 .07815 1.563 5,000 .OOI95 .039 42,000 .09025 1.805 6,000 .0024 .048 12,500,000 44,000 • II 97 2.394 7,000 .OO295 •°59 11,868,474 46,000 •1393 2.786 8,000 .0035 .070 11,428,571 48,000 .16255 3-251 1,245,762 9,000 .0038 .076 11,842,105 50,000 .2006 4.014 10,000 3 °° 10,000 .OO42 Set .00005 .0042 .084 Set .001 .084 11,904,761 52,000 300 52,000 .2259 Set .19825 •22955 4.518 Set 3.965 4 - 59 1 12,000 .0052 .104 11,538,461 54,000 .26605 5.321 14,000 .0062J .120 11,200,000 56,000 .29875 5-975 16,000 .0072 .144 II, III, III 58,000 .3263 6.526 18,000 .0082 .164 10,975,668 60,000 .3720 7 - 44 ° 20,000 300 20,000 .0089^ Set .00055 .0095 c . - 179 Set .on .190 11,172,184 300 60.000 62.000 64.000 68,900 Set .3496 . 399 i .4636 Set 6.992 7.982 9.272 22.000 24.000 .0109 .01265 .218 •253 10,009,082 9,494,071 „ -4714 1 Broke. 9.428 26,000 .01485 .297 8 , 755,555 i Tenacity per square inch, original section, 28,000 .0178 _ *356 7,865,168 68,900 pounds (48.44 kgs. per sq. cm.). 3 °° Set .00515 Set .103 Tenacity per square inch, fractured section, 28,000 .01815 •363 92,136 pounds (64.77 kgs. per sq. cm.). 30.000 32.000 34.000 .02235 .02755 .03625 •447 • sn . 7 2 5 Diameter of fractured section, .6900" (1.73 cm.). STRENGTH OF COPPER ALLOYS, 459 TABLE LXXXIIL TESTS BY TRANSVERSE STRESS. ALLOYS OF COPPER, TIN AND ZINC. Dimensions. — Length, 1=22" (55.88 cm.); breadth, b = 1.00" (2.54 cm.); depth, d — 1. 00" (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. Pounds. Inch- Inch. 3 6 .0004 10 .00x8 20 .0067 40 .0125 60 .0172 80 .0215 100 .0250 120 .0287 l 6 o •0359 2®0 .0437 IO .0018 3 .0003 200 <0435 240 .0500 280 00 VO (? 320 •0635 360 .0702 400 .0764 10 .0050 4 .0009 400 .0764 440 .0825 480 .0891 520 .0960 560 .1022 600 .1086 10 .005a 3 ... • .0001 600 .1084 640 .1157 680 .1234 720 .1305 760 .1:380 800 .1468 10 .0056 3 .0026 800 .1464 840 • I 549 880 .1627 920 .1716 960 .1808 1,000 .1905 h o >: 7,820,389 8,383,457 9^38,945 9,748,166 10,498,644 10,953,995 11,948,989 11,990,718 12,575,185 12,914,657 13,202,297 T 3, 434 , 278 i 3,7 i 6, 389 13,972,399 14,113,565 14,190,748 x 4, 355, 235 J 4, 474, 203 i4,49i,7i5 14,436,664 14,454,236 14,428,053 14,277,003 14,206,957 14,169,948 14,045,709 13,910,603 13,752,390 Pounds. Inch. Inch. .0132 .0098 Left 10 min. ; showed very slight increase of resistance. 1,000 | | | Left under strain. Resistance diminished in 5 min. to 996 lbs. Resistance diminished in 20 min. to 990 lbs. Resistance diminished in 1 hr. 55 m. 10985 lbs. 1,000 .1951 1,010 .1967 1,020 .1994 1,040 .2033 1,060 .2081 1,080 .2145 1,120 .2259 1,160 • 2373 I , 2 °° .2515 10 .0291 1 .3 .0261 12,500,184 Resistance increased in 20 min. to 9 lbs. 3 I Decrease of set, .0004 1,200 1,240 1,280 1,320 1,360 1,400 10 3 .0257 .2536 .2634 .2785 .2962 •3 T 43 • 3351 .0721 .0681 .0697 • 3351 .3516 .... .3713 • 1 Broke suddenly in mic 10,945,277 1,400 1,440 1,480 1,520 i,55o ringing sound. Breaking load, P — 1,550 lbs. Modulus of rupture, R = -^7-77, = 50,541 •20a (3,553 metric). 4^0 MATERIALS OF ENGINEERING— NON-FERROUS METALS , TABLE LXXXIII. — Continued. BAR NO. 5. Composition.— Original mixture : Cu, 88.135 ; Sn, 1.865 *, Zn, 10. Analysis: Cu, 89.50; Sn, 2.07; Zn, 8.11. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. Inch. Inch. 3 00x8 2° .0071 5,325,416 40 .0119 6,354,696 60 .0162 7 , 001,935 80 .0190 7,960,094 IOO .0224 8,439,831 120 • 0255 8,896,573 l6o .0314 9,633,235 200 •0379 9,976,370 .OIOI O .0059 D 200 .0381 .04.36 24O 280 .0511 io , 359, 026 320 .0584 10,359,028 360 .0658 10,343,283 400 .0727 10,401,776 10 .02 24 .0162 5 400 .0749 44.0, beam sinks. .0830 10,022,046 480 .0921 9,852,884 520 . 1086 560 .1309 600 .1631 6,954,660 10 .0849 3 .0820 600 . i6oq Left under strain. Resistance diminished in 1 min. to 584 lbs. Pounds. Inches. Inch. tc . o > H §2 1,000 1,020 1,040 1,060 l,o8o I. IOO Bar removed Breaking load, P--= 2,164,546 Resistance diminished in 41 min. to 570 lbs. 600 620 640 680 720 760 800 10 3 800 840 860 880 900 920 940 960 • *749 .1854 .2089 .2896 •3767 • 5394 .6984 .5811 .5681 •7i54 .9199 •9859 1.1389 1.26 1.36 1.56 1 -74 1.92 2.12 2.32 2.52 2.72 2.92 3-2 7 3 67 Modulus of rupture, R (metric, 2,250). 120 pounds 3 PI ■zbd? = 31,986 BAR NO. 7. Composition. — Original mixture : Cu, 66.885 ; Sn, 1.865 ; Zn, 31.25. ■2 ! 4.4.0 .0920 12,756,821 O IO .0024 480 . 1012 Beam sinks. 12,651,391 20 • 0^55 ..... | 9,699,400 520 .1109 40 .0114 1 9,359, 172 560 .1239 80 .0201 ..... 10,616,259 600 .1402 11,415,131 120 .0281 . — i 11,390,754 10 .0257 160 .0367 ..... 11,628,709 3 .0233 200 .0447 11,934,387 600 • 1433 IO .0060 . . Left under strain. 3 .OO4I Resistance diminished in 3 min. to 596 lbs. 200 • 04.4.3 Resistance diminished in to min to lbs. 24O •°5 1 3 | 12,478,758 Resistance diminished in i6h. 15m. . to 581 lbs. 280 .0602 12,385,645 IO I . 02Q0 I 320 .0678 1 12,589,165 'i ... .0274 360 .0748 12,837,309 Left under strain. 400 • 0831 ! 12,839,159 Resistance increased in to min. to 5 lbs. IO .OO9I 4 .0273 3 . 0066 581 « T 4.00 400 .0836 600 .1440 STRENGTH OF COPPER ALLOYS . 461 TABLE LXXXIII. (Bar No. 7).— Continued. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. Inch. Inch. Pounds. Inches . Inches. 620 .1496 I,C 7 .C 1,040 •7799 64O 1,080 • 9498 680 • J/J .1836 1,120 1.0549 720 1,160 1 . 19 760 . 2642 1,200 I . 37 / w 720 1,240 • .5/ I . ^7 760 1,280 • 0/ 1.75 800 .3069 6,952,976 I , 3 2 ° 1 *93 IO # I387 1 .^60 2 . I ”5 3 •1343 1,400 2 -33 3 •1334 1,440 2.61 800 .3099 1,480 3 ’ 11 840 .3471 1,500 3-76 • • • • • 880 - A2q6 5. 52 920 .5156 Bar removed. 960 .6145 Breaking load, P— 1,500. 1,000 10 .7117 . A 7 I /1 3,747,836 Modulus of rupture, j 49,599 3 1,000 .7169 • TV a T- .4668 (metric, 3,417). 2 BAR NO. 12. Composition.— -Original mixture: Cu, 58.22 ; Sn, 2 30; Zn, 39.48. 3 1 i° .0024 20 .0046 40 .0098 80 .0202 120 .0296 160 .0418 200 •0517 10 3 200 .0532 240 .0612 280 .0712 320 .0802 360 .0908 4°o . 1000 10 3 400 .1010 440 .1095 480 .1197 5 2 ° .1294 560 .1403 600 .1511 10 3 600 .1515 640 .1629 680 .1740 720 .1846 760 .1944 800 .2038 0032 0011 0027 0008 0032 0015 11,760,504 11,040,471 II )7 I2 i535 10,965,874 io ? 353,743 10,463,891 10,607,511 10,637,306 10,792,679 10,724,336 10,819,661 10,869,067 10.846,777 10,869,829 11,578^64 14,321,101 10,627,046 10,570,934 10,550,048 io,574,77i 10,6x7,922 10 .OO 43 3 .0032 800 .2028 840 .2142 10,607,511 880 .2247 10-593,349 920 • 2 344 10,616,562 960 • 2 433 10,672,909 1,000 .2550 10,607,511 10 .0064 3 .OO46 1,000 .2544 1,040 .2642 10,647,661 1,080 .2764 10,569,132 1,120 .2847 10,641,044 1,160 .2951 10,632,674 1,200 ,3062 10,600,509 IO .0114 3 .0093 1.500 onfin ^eft under strain. Resistance diminished in 55 min. to 1,194 lbs. 1,240 .3170 1,280 .3276 I, 3 20 .3398 T ,36o .3528 1,400 .3673 IO .0210 .OI93 3 .... 1,400 .3695 1,44° .3817 1,480 .3959 1,520 .4IO2 10,310,049 462 MATERIALS OF ENGINEERING— NON-FERROUS METALS, TABLE LXXXIII. (Bar No. 12).— Continued. LOAD. DEFLECTION. SET. Pounds . Inch . Inch . 1,560 .4236 1,600 • 4395 10 .0407 .0387 1,600 .4405 1,640 • 4537 1,680 • 47°4 1,720 .4882 1,760 .5042 1,800 -5205 10 .0743 „ 3 .0727 1,800 1,840 .5230 •5383 1,880 .5586 1,920 .5823 1,960 .6076 2,000 •6343 10 2 .1340 .1326 Left under strain. Resistance increased in 10 min. to 8 3 .1320 2,000 .6390 2,040 .6594 2,080 .6856 2,120 .7140 2,160 .7486 2,200 •7777 2,240 .8106 2,280 .8621 g u s 9,847,245 9,354, *74 8,955,262 7,651,812 Left under strain. Resistance decreased in 1 min. to 2,272 lbs. Resistance decreased in 3 min. to 2,268 lbs. Resistance decreased in 25 min. to 2,260 lbs. Resistance decreased in hr. to 2,256 lbs. 2,280 2,290 2,300 2,3 10 2,320 • 8665 I .8685 .8^22 • 8763 •8843 1 Resistance decreased in 3 min. to 2,312 lbs. Resistance decreased in 10 min. to 2,308 lbs. Resistance decreased in 66 hr. 13 m. to 2,260 lbs. 2,3 2,270 2,280 2,290 2,300 2,310 2,320 2,330 2,340 50, beam sinks. .8867 .8893 .8919 .8948 .8967 .8990 .9019 .9063 .9165 Left under strain. Resistance decreased in 10 min. to 2,342 lbs. 2,350 .9189 2,360 -9239 2,370 .9418 Pounds . 2,380 2,390 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 2,570 2,580 2,590 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 2,730 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 Inches . .9529 .9650 .9764 .9888 1.0048 1.0189 1-0333 1 .0438 i-o553 1 -°755 1.0865 1. 1013 1.1265 i-i34i 1-1475 1.1647 1. 1818 1.1918 1.2073 1 .2293 1.2445 1.2585 1.2851 1.3063 1.3288 i . 3406 1 -3556 1 -3747 1 -3973 1.4178 1 • 4447 1.4665 1 .4898 1-5057 ^SOS 1-5437 1.5603 1. 6106 1 . 6279 i -6395 1.6581 x . 6899 1.7285 1-7599 1-7793 1.8111 1.8553 1 . 8807 1.8936 1 -9453 Inch . O > y ■J H §3 5,472,552 4,331,697 Broke gradually in the middle. While putting on strain a slight crackling sound was heard a few seconds before breaking. Breaking load, P = 2,880 pounds. Modulus of rupture, r> 3 PI zbd ' 1 — 95,623 (metric, 6,722). STRENGTH OF COPPER ALLOYS. 463 TABLE LXXXIII. — Continued. BAR NO. 52. Composition.— Original mixture : Cu, 60 ; Sn, 5 ; Zn, 35. LOAD. DEFLECTION. SET. Pounds. Inch. Inch. 3 ..... 10 .0017 20 .0036 40 .0073 .... 80 .0148 120 .0237 160 .0327 200 .0408 10 .0022 3 zoo .0411 .0006 240 .0497 280 .0583 320 .0656 360 .0713 400 .0770 10 .0026 3 .0008 400 •0 777 440 .0839 480 .0915 520 • °993 560 .1068 600 • 1X37 10 .0047 3 .0026 600 .1148 640 . 1216 680 .1285 720 • 1353 760 .1420 800 .1487 o > (o £ p y ri P Q < O J S w 14,805,645 14,602,823 14,389,192 I3 ? 477,5 8 5 13,039,862 13,063,832 12,869,320 12,704,416 72,704,190 ■“3,455, 93 1 13,844,27° 13,975,955 13,980,442 i 3,955,8°4 13,973,864 14,063,440 14,626,432 14,102,841 i4, I 8x,934 14,263,500 14,336,709 Pounds. 10 3 800 840 Beam sinking 880 920 960 1,000 10 3 1,000 1,040 1,080 1,120 1,160 1,200 10 3 1,200 1,240 1,280 I, 320 II, 360 i,4°o .0157 3 ..... .0136 1,402 I Broke about 1 inch from the middle. Breaking load, P = 1,402 po unds. o pi Modulus of rupture, R = . TO 2 bd 2 (metric, 3,239). 46,076 BAR NO. 55. Composition. — Original mixture : Cu, 65 ; Sn, 5 ; Zn, 30. 3 10 .0018 20 .0037 14,923,498 40 .0081 13,633,811 80 .0168 13,146,888 120 .0253 13,094,906 160 .0341 12,954,119 200 .0422 13,084,581 IO .0020 3 .0001 200 •043 1 24O .0506 13,094,924 280 .0581 13,305,285 320 .0649 13,612,805 360 •0715 13,900,769 400 .0781 14,172,658 IO .0028 3 .0015 400 .0781 440 .0856 480 .0931 520 .0988 560 . 1058 600 .1129 10 ..... .0038 .0026 14,191,208 14,234,223 14,530,772 14,613,175 14,672,351 n ..... 600 .1129 640 .1195 680 .1265 720 • I 34 2 760 .1420 800 . 1495 JO .0064 .0042 14,786,125 14,840,914 14,812,293 14,776,364 r 4, 776, 762 0 800 . 1498 840 .1586 880 . 168c 920 . 1 796 14,622,290 14,461,578 14,142,41* 464 MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE LXXXIII. (Bar No. 55).— Continued , . 960 1,000 10 3 1,000 1,040 1,080 1,120 1,160 1,200 Io 3 1,200 1,240 1,280 DEFLECTION. SET. MODULUS OF ELASTICITY. Inch . .1906 | .2047 Inch . .0196 .0177 13,905,628 1:3,487,282 .2072 .2185 .2382 •2579 .2789 • 3 OI 4 1 .0597 .0576 .3036 .3272 •358o 10,912,409 Pounds . I , 3 2° 1,360 1,400 Inch . .3716 .4039 • 4433 3 1,400 1,440 i ,48o 1,520 1,525 Breaking load, P .4508 .4704 • 5165 . 5608 Broke in the middle. I nek . 1421 •1397 to . c h h« s « 8,719,01a 1,525 pounds. r,Pl Modulus of rupture, R = (metric, 3614). 2 bd * 51,369 BAR NO. 64. Composition. —Original mixture : Cu, 75 ; Sn, 10 ; Zn, 15. 3 10 .0019 20 .0036 40 .oo63 80 .0143 120 .0229 160 .0313 200 .0389 10 .0024 3 .0002 200 .0390 240 .0468 280 .0549 320 .0627 360 .0702 400 .0776 10 .0026 3 .0003 400 .0775 440 .0843 480 .0907 520 •°97 I 560 .1035 600 .1107 10 .OO49 3 .0021 600 .1115 640 .1179 680 .1251 720 .1323 760 •1395 800 .1472 10 .0081 3 .0057 800 .1482 840 .1557 880 .1647 920 .1738 960 .1847 1,000 .1979 10 .0224 3 .0195 1,000 .2001 1,040 1,080 .2113 .2258 1,120 .2438 1,160 .2661 1,200 .2858 10 .0637 3 .0607 1,200 .2927 1,240 .3077 1,280 .3286 2,320 1,360 .3536 .3816 1,400 .4111 10 •1473 3 •1443 1,400 .4186 1,440 .4413 1,480 • 4795 1,520 .5234 1,560 1,600 .5598 -5947 10 .2840 3 .2798 1,600 .6090 1,640 • 6399 1,680 •6755 1,720 i,75o . 7339 Broke near the middle. 15,122,613 16,012,177 15,228,364 14,264,121 i3,9i4,737 13,995,219 I 3, 959, 33 r i3,8»3,543 13,892,545 i3,959,33 T 14,031,290 14,207,721 14,405,661 r 4, 577,5H 14,728,108 14 , 752,853 14,776,293 14,796,224 14,813,990 14,829,914 14,793,825 14,685,542 !4, 544,151 14,409,115 14,148,277 !3, 754, 775 11,429,344 9,270,002 Breaking load, P — 1,750 pounds. Modulus of rupture, -.pi R = 58,345 (metric, 4,102). STRENGTH OF COPPER ALLOYS . 465 TABLE LXXXIII. — Continued. BAR NO. 68. Composition. — Original mixture : Cu, 80; Sn, 10; Zn, 10. Pounds. 3 20 40 80 120 160 200 xo 3 200 240 280 320 360 400 440 480 520 560 600 10 3 600 640 680 720 760 800 10 800 840 920 960 1,000 10 3 1,000 1,044 1,080 1,120 1,160 Inch. .0019 .0038 .0072 .0132 .0210 .0291 •0374 • 0374 .0456 .0536 .0617 .0699 .0786 .0853 .0921 .0991 .1063 • IZ 37 .1208 .1286 • 1365 .1444 .1526 .1528 .1623 .1725 .1839 •1955 .2126 .2166 .2323 .2527 .2780 .3060 Inch. .0025 .0006 .0067 .o°S3 .0150 .0130 .0417 .0405 13,668,369 14,427,725 15,739,337 J 4, 839, 942 14,278,983 13,887,648 13,668,369 13,566,365 13,468,990 z 3, 379, 554 13,266,871 z 3, 395, 96 z I T 3, 534,458 I 13,626,987 13,681,226 13.911,448 *3,759,793 13 , 732,139 13,698,407 13,668,368 13,614,630 12,215,380 Pounds. 1,200 10 3 1,200 1,240 1,280 1,320 1,360 1,400 10 3 1,400 I >44° 1,480 1,520 1,560 1,600 10 1,600 1,640 1,680 1,720 1,760 1,800 10 3 1,800 1,840 1,880 1,920 1,960 2,000 2,040 2,060 Inches. •3325 • 34i9 .3627 • 4037 .4400 •4934 •5647 .5720 .6010 .-6449 •7 Z 43 .7921 • 8645 .8808 .9409 1.0216 I « 1I 57 1.2321 I-34I7 1.3689 1.4464 1.5879 1.7029 1.8499 2.0079 2.2849 2-4479 e! h Inch. .1171 IT 53 .2951 • 2 934 .5468 • 543 2 .9589 .9546 9,372,595 6,438,437 806,460 3,484,072 586,772 Rollers flew apart. Continued tests on cast- iron supports. The bar broke at 2,320 pounds I with a total deflection of 2.797". Coefficient of elasticity, 2,154,099. Breaking load, P = 2,060 pounds. ; Modulus of rupture, R = _ 3 PI _ 2 bd 2 67,117 (metric, 4,718). 30 466 MA TERIALS OF ENGINEERING— NON-FFRROUS ME TALS. TABLE LXXXIII. — Continued. BAR NO. 71. Composition. — Original mixture : Cu, 85 ; Sn, 10 ; Zn, 5. Pounds . 3 10 40 90 120 160 200 10 3 200 240 280 320 36° 400 10 3 400 440 480 520 560 600 10 3 600 640 680 720 760 800 10 3 800 840 880 920 960 Left under Resistance Resistance Resistance Resistance Resistance Resistance Resistance Resistance Resistance Resistance Resistance Resistance 920 94c 945 950 955 Inch. .0013 .0031 .0064 .0131 .0201 .0275 .0355 .0364 .0426 .0508 .0589 .0670 .0752 • °759 .0842 .0919 .0998 • io73 •ii35 ' II 4 I ,1138 .1270 ■ T 347 1425 ,1501 . 1506 .1598 .1691 .1787 .1894 strain. decreased decreased decreased decreased decreased decreased decreased decreased decreased decreased decreased decreased .1896 .1914 .1920 •1943 • 1951 Inch. .0024 .0015 .0042 .0026 .0068 .0051 .oi34 .0116 35 Q < O s w *5, 737.217 I 5.245, 4 28 14,896,295 x 4, 562, 759 14,192,108 *3,742,357 13 , 742,357 13, 444, 7 86 13,252,393 13,106,516 12,974,833 12,746,771 12,740,466 12,709,614 io,730,57i 12,906,151 Inch . .1958 .1969 .1983 .1994 .2005 .2017 .2031 .2066 .2078 .2166 .2306 ■ 2537 .2832 13,031,152 13,060,650 J 3, 038, 405 13,009,431 13,000,763 in 1 min. to 944 lbs. in 2 min. to 940 lbs. in 3 min. to 938 lbs. in 4 min. to 937 lbs. in 9 min. to 932 lbs. in 14 min. to 930^ lbs in 29 min. to 926 lbs. in 44 min. to 925 lbs. t Vi f t a min tn no ... _ hr in 1 hr in 2 hr in 2 hr 14 min. to 923 lbs. 44 min. to 922 lbs. 44 min. to 920 lbs. 74 min. to 920 lbs. Pounds. 960 965 970 975 980 985 990 1,000 10 3 1,000 1,040 1,080 1,120 1,160 Left under strain. Resistance decreased Resistance decreased Resistance decreased Resistance decreased Resistance decreased Resistance decreased Resistance decreased Resistance decreased Resistance decreased Resistance decreased 1,066 I,TOO 1, no 1,120 1,130 i,i35 1,140 1 , t 45 1,150 I » I 55 1,160 1, *65 I , I 7° i,i75 1,180 1,200 TO 3 1,200 1,240 1,280 I ,320 1,360 1,400 10 3 1,400 1,440 1,480 1,520 1,560 Inch. h . °£ 35 & & §3 11,806,720 •0397 .0382 in 2 min. to 1,118 lbs. in 3 min. to 1,112 lbs. in 4 min. to 1,110 lbs. in 7 min. to 1,104 lbs. in 12 min. to 1,10c lbs. in 27 min. to 1,093 lbs. in 42 min. to 1,090 lbs. in 1 hr. 12m. to 1,087 lbs. in 2 hr. 12m. to 1,082 lbs. in 16 hr. 12m. to 1,066 lbs. .2833 .2897 .2914 .2937 .2958 .2970 .2986 .3005 .3023 • 3°45 .3076 .3110 • 3 I 4 I .3175 .3221 • 3304 .1166 .1141 .3305 • 35I 1 .3691 .4204 • 47°4 .5296 .2794 .2764 .5500 .6052 . 6524 •7356 .8214 8,859,329 6,448,116 STRENGTH OF COPPER ALLOYS. 4 67 TABLE LXXXIII. (Bar No. 71). — Continued, Pounds. 1,600 10 3 1,600 1,640 1,680 1,720 1,760 1,800 1,840 1,880 Inches. .9206 .9486 1.0198 1.1191 1.2726 I-379 1 1.5061 1.6896 1.8556 SET. MODULUS OF ELASTICITY. Inch. .6169 .6132 Q < O j S w Pounds. Inches. Inch, 1,920 2.0401 1,960 2.3676 2,000 2.5621 The beam could not be raised with an in* crease of load. Breaking load, P = 2,000 pounds. Modulus of rupture, ■xPl R = - — = 62,470 (4,392 metric). 2 bd 1 BAR NO. 72. Composition. — Original mixture : Cu, 90; Sn, 5 j Zn, 5. 630 .1397 635 .1406 640 • I 4 I 5 645 .•1426 650 .1441 655 • 1456 660 • 1473 680 •1525 720 .1701 760 .1969 800 .2287 IO .0997 3 .0979 800 ■ 2451 840 .2814 Left under strain. Resistance decreased in 1 m. to 8< 3 10 20 40 80 120 160 200 10 3 200 240 280 320 360 400 10 3 400 440 480 520 560 600 10 600 0018 0036 0069 oi45 0221 0297 0374 0376 0461 0535 0608 0681 0754 0757 0827 0907 0992 1092 1202 1246 1342 640 Left under strain. Resistance decreased in Resistance decreased in Resistance decreased in Resistance decreased in Resistance decreased in Resistance decreased in Resistance decreased in Resistance decreased in Resistance decreased in Resistance decreased in Resistance decreased in .0035 .0019 .0071 .0049 .0246 •0233 14, 309,323 14,862,866 14,145,348 13,921,359 13,811,961 13,710,398 13,347,532 13,418,250 13,493,919 13,553,364 13,601,300 13,640,770 13,568.306 13,439,504 13,180,961 12,797,923 59i 1 .1342 620 1 .1387 625 | .1392 1 m. 2 m. 3 m. 4 m. 5 m. 6 m. 11 m. 16 m. 19 hrs 40 hrs. 42 hrs. to 628 lbs. to 626 lbs. to 624 lbs. to 623 lbs. to 622 lbs. to 621 lbs. to 618 lbs. to 617 lbs. 51 m. to 596 lbs. 36 m. to 591 lbs. 11 m. to 591 lbs. 8,968,410 Resistance decreased in 2 m. to 795 lbs. Resistance decreased in 3 m. to 792 lbs. Resistance decreased in 4 m. to 790 lbs. Resistance decreased in 5 m. to 789 lbs. Resistance decreased in 6 m. to 788 lbs. Resistance decreased in 13 m. to 782 lbs. Resistance decreased in 21 m. to 779 lbs Resistance decreased in 31 m. to 777 lbs. Resistance decreased in 46 m. to 774 lbs. Resistance decreased in 1 hr. 1 m. to 772 lbs Resistance decreased in 1 hr. 16 m. to 771J lbs Resistance decreased in 1 hr. 46 m. to 770 lbs Resistance decreased in 3 hr. im. to 766 lbs Resistance decreased in 4 hr. i m. to 764 lbs Resistance decreased in 5 hr. 31 m. to 763 lbs. Resistance decreased in 21 hr. 15 m. to 752^ lbs. Resistance decreased in 23 hr. 45 m. to 752 lbs Resistance decreased in 24 hr. 36 m. to 752 lbs 752 .2814 780 .2865 800 .2900 820 .2951 825 .2973 830 .3006 835 .3050 840 •3094 463 MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE LXXXIII. (Bar No. 72 ).— Continued. LOAD. DEFLECTION. SET. Pounds . Inches . Inch . 845 • 3i75 850 •3237 860 • 33 x 7 880 .35io 920 .4320 960 .5587 1,000 •7 I 9 I 10 .5485 3 • 5455 1,000 .7567 1,040 .8634 1,080 1. 1001 & y D ( n Q < O J S w 3 , 565,351 Pounds , 1,120 1,160 1,200 1,240 1,280 Inches . 1.3085 *•5835 1.8925 2 . 1905 2.6325 Inch . fc . SS 83 1,629,090 135^ The beam could "not be raised with an ia crease of weight. Breaking load, P = 1,280 pounds. Modulus of rupture, _3 Pl_ R rid * = 41,334 (2,906 metric). BAR NO. 73. Composition. — Original mixture : Cu, 55 ; Sn, 5 ; Zn, 44.5. 3 10 20 40 80 120 160 200 10 3 200 240 280 320 360 400 10 3' 400 440 480 520 560 600 10 3 600 640 680 720 760 800 10 3 800 840 880 920 960 1,000 10 3 1,000 1,040 1,080 1,120 1,160 1,200 .0051 11,125,506 .0x22 9,301,654 .0217 10,459,002 .0321 10,605,623 .04x7 10,885,388 .0519 .0024 !o, 932, 579 .0024 .0520 .0631 10,790,506 10,822,358 .0734 .0813 11,166,563 .0899 11,360,639 .1001 .0028 11,336,420 .0008 .0997 11,327,423 .1102 • XI 99 n, 357, 480 11,348,016 .1300 .1402 11,331,828 • 1516 .0046 11,228,276 .0018 .1518 .1623 11,187,203 .1745 II ,°55,376 io , 8 59,347 .1881 .2024 10,652,784 .2164 .0140 .0119 10,015,963 .2x67 .2296 10,379,284 .2443 10,219,254 10,996,882 .2585 .2758 9,874,995 .2923 .0440 9,705,798 .0417 .2948 .3146 9,378,526 .3338 .3571 • 3 8 5 x .4271 9,179,045 8,897,912 7,970,978 10 .1286 3 .1265 1,200 .4284 1,240 • 4575 1,280 •4973 I ,3 2 o 1,360 .5390 .5876 1,400 .6419 IO .2986 3 .2965 Left under strain. Resistance increased in 20 m. to 5J Resistance increased in 15 hrs. 45 m 10 .2970 3 •2933 1,400 .6508 1,440 • 7 I 97 1,480 •7853 1,520 • 8571 1,560 .9485 1,600 1.0361 1,640 1.1295 1,680 1.2316 1,720 1-3347 1,760 1-4535 1,800 !*5744 xo 1.1384 3 1.1358 1,800 1 . 5866 1,840 1 *7459 1,880 1.8619 1,920 2.0244 i, 9 6 ° 2 . 2087 2 oOO 2.3178 10 1.9x44 3 1.9096 2,000 2-35I3 0 . . . . 2,000 2.7738 2,040 3.0498 2,080 _ 3.0498 . 6,187,577 4,381,050 3,243,526 2,448,014 aftef this pressure was attained. Breaking load, P = 2,100 pounds. Modulus of rupture, r>Pl R ~ rid ? = 72,308 < metric » S,o83). STRENGTH OF COPPER ALLOYS. 469 TABLE LX XXIII. — Conti nued. BAR NO. 74. Composition.— Original mixture : Cu, 67.5 ; Sn, 5 ; Zn, 27.5. SET. MODULUS of ELASTICITY. Inch. 16,821,775 17,390,724 15,208,723 !5, 278, 489 15,105,267 14,125,146 .0025 .0009 13,820,378 13,828,573 13,834,729 i 3*7 I2 ,725 13*723.572 .oo?8 .0013 13*783.981 13*834,726 13,918,109 I 4*°4°,945 14,113,185 .0039 .0024 14,154,417 14,352,805 14,491,853 I 14,628,641 14,724,630 .0044 .0032 14,784,385 14,857*187 j Pounds. 3 10 20 40 80 120 160 200 10 3 200 240 280 320 360 400 10 3 400 440 480 520 560 600 10 3 600 640 680 720 760 8co 10 3 800 840 880 Inch. .0016 .0033 .0070 .0146 .0218 .0294 •0393 0396 0482 0562 0642 0727 0809 0807 0886 0963 1037 1107 180 [177 t2 55 13-5 [ 379 1442 1508 *5*4 ^577 1644 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 3 1,600 1,640 1,660 Inch. , 1721 [801 1898 1980 2083 2211 2333 2469 2498 2632 2791 3013 3183 3360 3396 3521 3727 4013 4301 4620 Inch. .0083 .0068 .0190 • 0175 .0521 .0503 .1167 .1151 . 4621 .4874 Broke. Breaking load, P — 1,660 pounds. Modulus of rupture, 3PI ^ = 2^2 = 55,976 (metric, Cu . 35 rf h P tr . P < O J S w 14,871,767 14,794,934 14,701,230 14,578,869 1 4*39°,973 13,490,121 12,159,913 10,5x3,107 9,610,361 3*935)- BAR NO. 76. Composition.— Original mixture: Cu, 80; Sn, 12.5; Zn, 7.5. 3 360 400 .O75O 12,714,988 10 • 0021 • O826 12,827,876 20 .OO53 9,996,061 IO .OO46 40 • OIOQ Q.720.Q4I O .0022 80 .0193 10,980,131 O 400 .0824 120 / .0271 11,729,695 440 .0897 12,993,767 160 .0361 11,740,527 480 .0964 13,189,824 200 .0463 1I *442,576 520 .1031 13*360,397 10 .0040 560 .1101 13*473*348 3 .0016 600 .1166 13,630,993 200 .0468 IO .OO57 24.0 .0546 II, 64^7 64 •3 .OO35 280 .0614 * W TJ1 / V - /, T 12,079,930 I Left under strain. 320 .0682 12,429,120 1 Resistance increased in 1 hour to 6 pounds. 470 MATERIALS OF ENGINEERING— NON-FERROUS METALS. TABLE LXXXIII. (Bar No. 76 ).— Continued. LOAD. DEFLECTION. SET. < MODULUS OF ELASTICITY. Pounds. Inch. Inch. .0031 640 . 1232 13,760,813 680 . 1301 13,845,426 720 .1366 13,962,296 760 .1440 13,980,603 800 .1506 14,071,480 10 .0081 3 .0064 800 - 1 ro6 840 •1587 14,020,942 880 •1675 13,950,222 920 .1767 13,791,965 960 . i860 13,671,035 1,000 •1954 13,556,581 10 .0182 3 .0156 1,000 • 1976 1,040 .2064 13,347,452 1,080 .2173 1,120 .2299 1,160 •2434 1,200 .2594 12,254,229 10 .0447 3 .0428 1,200 . 2646 1,240 .2766 1,280 . 2926 1,320 •3126 1,360 .3313 1,400 •3529 10,508,678 IO .0991 SS J u D 5> Q < O J s « Pounds. 3 1,400 1,440 1,480 1,520 1,560 1,600 10 3 1,600 1,640 1,680 1,720 1,760 1,800 10 3 1,800 1,840 1,880 1,920 1,960 2,000 10 Inch. 3626 379i 4036 4364 4656 5081 5163 5364 5706 5986 6 559 6990 7148 7579 7965 8485 9090 9652 Inch. .0964 .2011 .1983 .3462 .3425 .5518 •5473 8,209,046 6,821,346 5,5°8,33° Broke while putting strain on and before it had reached 1,950 pounds. Breaking load, P = 2,000 pounds. Modulus of rupture, 3 PI R = IbcP ~ 66,073 ( metric ’ 4,645). BAR NO. 77. Composition. — Original mixture : Cu, 82.5 ; Sn, 15 ; Zn, 25. 3 10 .0012 20 .0031 40 .0071 80 .0154 120 •0235 160 .0307 200 .0421 10 3 200 .0422 240 .0498 280 .0575 320 .0655 360 .0732 400 .0800 10 3 400 .0802 440 .0874 480 .0950 520 . IOI7 560 . 1090 .0021 .0006 .0025 .0012 17,107,474 14,938,924 13,774,851 13,540,381 13,819,719 12,596,953 12,779,076 12,912,424 12,954,669 13,040,943 13,258,292 i3,349,3i3 13.396,852 13,558,134 13,623,198 600 .ii55 10 .0027 3 .0014 600 .1161 640 . 1217 680 .1286 720 .1361 760 .1437 800 . 1506 10 .0046 Left under strain. 14 10 3 800 840 880 920 960 1,000 13,774,451 13 , 944,630 14,021,209 14,027,877 14,024,081 14,085,034 .0046 .0043 .0027 .1463 .1562 .1627 .1691 .1775 .1857 .0125 .0105 14,259,881 14,342,099 14,425,528 14,34!, 363 14,279,259 STRENGTH OF COPPER ALLO YS. 471 TABLE LXXXIII. (Bar No. 77).— Continued . LOAD. DEFLECTION. SET. MODULUS OF ELASTICITY. Pounds. Inch. Inch. T non 1,040 .1940 14,215,075 1,080 .2049 ... . 1,120 .2165 1, 160 • 2310 1,200 .2447 i3,°°3>632 10 .0311 3 .0275 1,200 2473 1,240 .2615 1,280 .279 1 1,320 .2992 . OT7J. 1,400 * O x / r •3390 10,823,095 10 .0822 0 .0800 0 1,400 .3430 1,440 • 3599 1,480 . 3860 1,520 • 4*5° 1,560 . 4472 1,600 .4823 10 .1730 3 •1705 1,600 .4929 8,607,535 LOAD. W Q Pounds. I 1,640 1,680 ! 1,720 I 1,760 I 1,800 10 3 1,800 1,840 1,880 1,920 1,960 2,000 IO Inches. .5167 • 5528 .5847 .6287 .6807 .6950 .7356 .7842 .8311 .8924 •9558 3 2,000 2,040 2,080 2,090 .9762 1. 0197 1 . 0895 Broke. Breaking load, P = 2,090 Modulus of rupture, ° > H g 3 ►J H D Inch. 3181 3156 5305 5247 7,011,877 5,548,564 pounds. R 3PI 2 bd* = 69,045 (metric, 4,854). bar no. 78 Composition.— Original mixture : Cu, 60 ; Sn, 2.5 ; Zn, 37.5. 3 10 .0014 20 .0079 40 .01x9 80 • OI 97 120 .0284 160 •°357 200 .0431 10 3 200 .0446 240 .0513 280 .0600 320 .0683 360 .0756 400 .0839 10 3 400 .0840 440 .0917 480 .0996 520 .1079 560 .1158 600 • 1235 10 600 .1239 640 1319 0019 0001 0013 0002 0032 0012 7, 124,701 9,459,685 11,428,458 11,891 ,227 12,612,918 *3,059, J 9 8 13,166,112 13 , 133,199 13,185,394 13,401,225 I3,4i7,i97 13,503,526 13,562,685 13,562,685 13,609,517 13,672,506 13,655,229 680 .1307 720 .1489 760 .1581 800 .1676 10 .0083 3 .0070 800 .1683 840 .1785 880 .1887 920 .2010 960 •2137 1,000 .2256 10 .0215 3 .0201 1,000 .2244 1,040 .2426 1,080 •2595 1,120 .2791 1,160 .2998 1,200 .3244 10 .0566 3 .0546 1,200 •3245 ..... 1,240 •3419 1,280 .3676 13,698,602 13,608,229 13,528,371 13 , 432,210 13,243,564 I 3, I2 4, 2 54 *2,474,544 10,410,323 Left under strain. Resistance decreased in 2 Resistance decreased in 4 min. to 1,265 lbs. min. to 1,260 lbs. 4 / 2 MATERIALS OF ENGINEERING— NON-FERROUS METALS TABLE LXXXIII. (Bar No. 78).— Continued. Pounds. Inch. Inch. Resistance decreased in 7 min. to 1,257! lbs. Resistance decreased in 22 min. to 1,253! lbs. Resistance decreased in 4 h. 52 m. to 1,245! lbs, Resistance decreased in 12 h 1,260 • 3699 ** ' 1,270 • 37 x 8 1,280 • 374 i 1,290 .3762 i,3°o .3788 1,320 1,360 .3852 • 43 ii 1,400 .4760 10 .1381 3 .1360 1,400 • 4775 1,440 • 5 OI 7 13480 .5430 1,520 .5965 1,560 .6476 1,600 • 7°44 10 .2942 3 .2921 1,600 .7064 32 m. to 1,244 lbs. 8,277,226 6,392,409 R = 3 PI o-bd " 1 LOAD. DEFLECTION. SET. Pounds. Inches. Inch. 1,640 • 7345 1,680 • 7979 1,720 .8654 1,760 .9268 1,800 1.0156 10 •5333 3 .5306 1,800 1. 0181 1,840 1 .0456 1,880 1-1513 1,920 1.2366 1,960 1 . 3206 2,000 1.4426 10 .8821 3 .8800 2,000 1-4574 2,030 Broke in the middle. Breaking • load, P = 2 ,030 pounds. |J H D Q < O 2 « 4,987,853 3,901,644 69,508 (metric, 4,886). bar no. 80. Composition. — Original mixture : Cu, 77.5 ; Sn, 10; Zn, 12.5. 3 680 . TOT e 10 .0014 720 .1364 13,871,289 20 ! .0083 6,332,141 760 • 1445 13,821,159 40 .0111 9,469,689 800 • 1515 13,876,377 80 .0208 10,107,072 10 .0104 120 .0290 10,873,815 ■a .OO85 160 .0368 11,425,387 800 . TK24. 200 .0448 n,73i,423 840 • L D^ T* . 1601 13,787,536 10 .0019 880 .1690 13,683,421 3 .0005 920 . 1800 13,364,351 200 • °449 060 • ICKQ 240 .0523 12,058,914 1,000 .2099 12,519,481 280 •0585 12,577,687 10 .0297 320 .0661 12,721,759 3 .0279 360 .0740 12,784,079 1 ,000 .2130 400 .0814 12,913,21 1 1. 040 • 2251 10 .0024 1,080 . 2410 3 .OOIO 1 . 120 . 261 5 400 .0810 I,l6o .2824 440 .0884 I 3,°79,74 I 1,200 •3023 10,431,381 480 •0955 13,207,981 IO .0770 520 • 1025 I 3,33 I ,47 2 3 .0752 560 .1095 13,439,173 1,200 . 3086 600 .1165 13,533,934 1,240 •3249 10 .0045 1,280 . 1445 3 .0029 1,320 • 3765 600 .1165 1,360 .4039 640 •1235 T 3, 617, 950 1,400 -4475 8,221,172 680 • L304 13,703,452 10 .1776 Left under strain Q .1747 Resistance decreased in 43 min. to 672 pounds. J 1,400 •4595 • / 't/ STRENGTH OF COPPER ALLOYS . 473 TABLE LXXXIII. (Bar No. 80 ).— Continued. DEFLECTION. SET. MODULUS OF ELASTICITY. Inch . . 4880 .5215 .5710 .6148 .6675 Inch . • 3435 .3410 6,293,140 .6760 .7096 •7573 • 8255 .8785 .9628 4,912,868 LOAD. DEFLECTION. SET. Pounds . Inches . Inch . IO .5756 3 • 57 l8 1,800 • 9777 1,840 1. 0177 1,880 1.0903 1,920 1 . 1930 1,960 Broke just after beam Pounds . 1,440 1,480 1,520 1,560 1,600 10 3 1,600 1,640 1,680 1,720 1,760 1,800 a < o j S w Breaking load, P = 1,960 pounds. Modulus of rupture, = 63,849 (metric, 4,489). BAH NO. 87. •e : Cu, 77.5 ; Sn, 12.5 ; Zn, 10. 3 .0106 1,000 .1912 1,040 1,080 .2004 .2113 1,120 .2225 1,160 • 2377 1,200 .2570 10 .0380 3 .0348 1,200 .2592 1,240 .2705 1,280 .2845 1,320 .3029 i ,36o .3240 1,400 •3493 10 .0912 3 .0892 1,400 • 3553 1,440 .3690 1,480 •3905 1,520 •4!34 1,560 •4597 1,600 • 4950 10 • 1865 3 .1830 1,600 •5043 1,640 .5225 1,680 55 T 3 1, 72c 6008 1,76c .6490 1, 80c .6885 10 [3288 3 • 3245 O : 00 .7050 1,825 Broke. Breaking load, P = 1,825 pounds. Modulus of rupture, >3 II N) 1, % 11 ON 1,705 (metric, 3 IO 20 40 80 120 l6o 200 IO 3 200 24O 280 3 2 ° 360 400 IO 3 400 440 480 520 560 600 IO 3 600 640 680 720 760 800 10 3 800 840 880 920 960 1,000 0018 0063 0108 0185 0263 0336 0415 0427 0520 0603 0675 °743 0816 0817 0887 0958 1025 1089 ii53 1161 1219 1284 1348 I 4 I 3 1485 T 493 1557 1630 1707 1794 1897 .0021 .0006 • 0035 .0018 .0043 .0021 .0055 .0038 8,550,829 9,975,965 11,647,614 12,289,782 12,826,242 12,980,775 12,431,587 12,507,172 12,769,235 12,050,657 13,203,483 13,361,271 13,495,668 13,664,637 13,850,926 14,016,565 14,141,485 14,264,731 14,386,704 14,486,388 14,510,495 14,53!, 465 14,541,654 14,516,869 J 4, 413,435 12,576,762 IO , 795, 632 8,706,298 7,041,858 AL>. tnds. 3 io 20 4° 8o 120 160 200 IO 3 200 240 280 320 360 400 IO 3 400 440 480 520 560 600 IO 3 600 640 680 720 760 800 IO „ 3 800 840 880 920 960 ,000 10 ,000 ,040 ,080 ,120 ,160 ,200 OF ENGINEERING— NON-FERRO US METALS. TABLE LXXXIII . — Continued re : Cu, 82. 5 ; Sn, 12.5 ; Zn, 5. ! z 0 H LOAD. U w -1 b w Q SET. Pounds. Inch. Inch. IO .0520 3 .2726 .0494 1,200 1 ,240 .2864 1,280 • 3065 I ,3 2 ° 1,360 •3258 •3487 1,400 • 3730 10 .1X53 3 . 1124 1,400 .3825 1,440 1,480 .4017 .4326 1,520 •4733 j 1,560 .5062 1,600 • 5520 10 .2431 3 •2399 ! 1,600 .5649 1,640 .5875 1,680 .6242 1,720 .6828 1,760 .7412 1,800 .8048 10 • 4380 3 .4328 Left under strain. Resistance increased in 1 hour 1 10 .4306 3 •4287 1,800 .8168 1,840 .8490 1,880 .9086 1,920 1,960 .9788 1.0520 2 JOO 1.1326 10 .7059 3 1.1576 .7014 2,000 2,040 1-2x73 2,080 1 . 2980 2,120 1 .6100 Inch. .0023 .0003 .0038 ,0017 .0050 .0039 .0098 .0075 .0215 .0T94 £5 "s; Q < S M 11,327,661 11,831,112 12,169,145 12,576,378 12,601,287 12,985,365 12,551,671 12,790,394 12,967,797 13,145,680 13,190,091 13.377,788 13 , 557,691 1:3,589,062 13,639,627 13,839,806 13,818,016 13,959,508 13,942,939 I 3,937, I 73 13,905,974 13,836,741 13,735,503 13 , 593,199 13,424,108 10,791,095 D a, Q < O J S w 9,99 r ,4 2 3 7,7 I 5,943 5,953,778 4,700,689 Broke just after beam rose. Breaking load, P — 2,120 pounds. Modulus of rupture, R — = 69,960 (metric, 4,918). 2.0a Z ;au. aids. 3 io 20 40 80 120 l6o 200 IO 3 200 24O 280 3 2 ° 360 400 IO 3 400 440 480 520 560 600 10 3 600 640 680 720 760 800 10 „ 3 800 840 880 920 960 ,000 10 3 ,000 OF COPPER ALLOYS. 4/5 TABLE LXXXIII. — Continued. BAR NO. 89. dsition. — Original mixture : Cu, 85 ; Sn, 12.5 ; Zn, 2.5. SET. & U g P 5 1/5 o < o a 2 « Inch. 7.877,604 9.424,989 ..... 10,199,024 10,845,190 11,505,164 11,886,372 .0031 .0010 •0053 .0031 .0084 .0049 .0172 .0143 11,816,403 11,918,049 12,168,285 12,419,811 12,566,652 12,690,260 12,915,497 13.007,377 13,066,650 13,107,604 13,205,304 I 3, 273,061 I3,3i5,i59 13,335,359 x 3, 244, 652 13,101,403 .0438 .0410 11,651,201 LOAD. DEFLECTION. Pounds. Inches. 1,080 .2647 1,120 .2880 1,160 •3193 1,200 .3505 10 3 1,200 .3625 1,240 .3993 1,280 .4435 1,320 .513° 1,360 •5783 1,400 .6527 10 3 1,400 .6743 1,440 .7230 1,480 .8345 !,520 .9425 1,560 1.0777 1,600 I. 2199 IO 3 1,600 1.2255 1,640 I *3 I 45 1,680 1.4685 1,720 i. 6S95 1,740 1,760 1.7065 1.8645 1,780 1-9655 1,800 2.0745 1,820 2.1805 1,840 2.2995 1,860 2.4075 1,880 2.5425 1,900 2.6985 1,920 2.8285 The beam could not crease of load. Breaking ■ load, P= 1 Modulus of rupture, /? ^ Pl * R 2 bd *~ 6 SET. MODULUS OF | ELASTICITY. Inch. .1245 .1214 9,035,081 •3707 .3671 5,660,481 .8472 .8423 3,461,264 2,257,161 .... be raised with an in- )2o pounds. •,405 (metric, 4,387). 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 ALLO YS. 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 i,ooo° 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, B 2 = C T\ 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 (see Appendix) : 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 Ol6 546 11,000 77 545 290 25,000 176 2,032 1, hi 0 0 270. 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 ENGINEERING— NON-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 I 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. 1, 535 pounds, 12.5 percent.; No. 2, 825 pounds, 1 6 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. 1, at 400° F. (204° C.) the tensile strength had fallen to 245 lbs., 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 0 C.). At 350° F. (177 0 C.), the tensile strength was 450 lbs., 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. Bach finds bronze sensitive to change of temperature, in some cases losing 6 per cent, tenacity at 400° F. and 50 per cent, at 6oo°. The alloy Cu. 91, Sn. 5, Zn. 4, useful with low steam-pressures, is not probably reliable with high pressure or superheat. THE EFFECT OF ITEAT ON TENACITY OF KALCIIOID ALLOYS- CONDITIONS AFFECTING STRENGTH OF ALLO YS. 479 04 00 VO CO •A;i[pona Per ct. m 04 m c* Cv CO Cn co m m in m 04 04 04 04 04 3-75 5- u • 0 o 0 in o 0 0 0 in 0 Copp Zinc. •apsuax 0 o* $s oo M3 vo m m 0 VO vo vo vo vo C K X g - u H m m 04 O' a I a UhN •Ajiinona • 31 TSU 3 X • 3 ITSU 3 X n co co m 04 0 m VO VO VO vo 0 10 0 -<1- 0 O 00 t-» N 00 « 2. ° O h sy J h D Q O 5 , 574,991 5,310,020 5,635,593 3,596,764 in 1 minute to decreased in 3 minutes to 2 (/) O to r x Pounds. Inch. Resistance decreased pounds. Inch. in 8 minutes < ►j to £ O H to 56 0.3033 0.3827 0.6403 0.8091 1.07 1.36 IOO no 120 I30 I 3 ° Cont’d 1 min. 140 150 I Ran pressure-screw down slowly till deflection was more than 3 inches ; the scale-beam vibrating- all the time about 150 pounds. Bent without breaking-. Breaking load, P — 150 pounds. o pi Modulus of rupture, R = = 4,559 (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 1x1x22 inches. NO. OF TEST. MATERIAL PARTS. LOAD. DEFLEC- TION. TIME. INCREASED DEFLEC- TION. BREAKING WEIGHT. Tin. Copper. Pounds. Inches. Inches. Pounds. 7 IOO 600 o-534 5 minutes .... 0.009 650 8 1.9 sO 00 475 1.762 3 minutes 0.291 S°° 2.108 3 minutes 0.488 500 9 7.2 92.8 950 0.348 5 minutes 0.081 1,350 10 10. 90. 950 0-395 5 minutes 0.021 1,485 3-447 13 minutes 4.087 1,485 II 9°-3 9-7 100 0.085 10 minutes .... 0.021 120 0.140 10 minutes 0.055 140 0.221 10 minutes 0.098 140 0.319 10 minutes .... 0.038 140 1 °-357 40 hours 0.920 32 49$ MATERIALS OF ENGINEERING-NON-FERROUS METALS. TABLE XCII. — Continued. NO. OF TEST. I MATERIAL PARTS. LOAD. DEFLEC- TION. TIME. INCREASED DEFLEC- TION. BREAKING WEIGHT. Tin. Copper. Pounds. Inches. Inches. Pounds. 160 1.294 10 minutes 0.025 160 1.320 1 day 1. 000 160 2.320 1 day 1. 000 160 3.320 1 day 1 .000 160 12 98.89 1. 11 90 0.243 5 minutes 0.063 .... 120 0.736 15 minutes . . . 1.055 .... 120 1.791 30 minutes 0.748 .... 120 2.539 45 minutes o.595 120 3- I 34 12 hours 8.000 120 J 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 : H W k O MATERIAL. TIME UNDER STRESS. ANGLE OF TOR- SION. FALL OF PENCIL. REMARKS. 6 z Tin. Cop- per. +1 40 hours . . . ° 65 0.06 inch. . . Recovered after further distortion of i°. t2 IOO i hour .... 180 0. i inch... Recovered in 8°. +3 2 hours . . . 280 0.1 inch... Recovered in 8o°. 4 99-44 0.56 12 minutes . $380 50 per cent. Did not recover. 5 98.89 1 . n Behaved like No. 4. 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- existent, 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 Cu, 82.5 Sn.— Dimensions : Length between supports, 22"; Breadth, 0.996"; Depth, 0.983". MODULUS OF ELASTICITY. SET. PI 3 LOAD. 4 a bd 3 1 ' Inch. 8,039,339 7,356,258 6,594,77° 6,167,163 Beam sinks slowly. 5,638,814 DEFLEC- TION. A MODULUS OF ELASTICITY. PP 4 A bd* 0.0092 0.0821 ,3084 5,472,481 4,899,597 4,320,565 3,771,245 3,377,873 2,697,980 832,406 The beam was observed to rise, and another reading of set was taken in 2 minutes. 5 I . 0.3022 | The beam rose again, pushed forward the poise till beam balanced at 10 pounds. Time 2 minutes. In 2 minutes more, beam balanced at 14 pounds. The pressure-screw was then run back till beam* balanced again at 5 pounds, and another reading of set taken. Pounds. Inches. Inch. 5 I , 0.2998 I Beam rose again. In 2 minutes balanced at 10 pounds. In 10 minutes balanced at 16 pounds. In 39 minutes balanced at 23 pounds. Ran back pressure-screw till beam balanced again at 5 pounds. 5 | • | 0.2902 | In 4 minutes beam rose again. In 23 minutes beam balanced at 14 pounds. In 1 hour and 36 minutes beam balanced at 20 pounds. Ran back pressure-screw till beam balanced again at 5 pounds. 5 1 .... | 0.2845 1 ; Total decrease 0/ set in 2 hours and 20 min- utes 0.3084 — 0.2S45 = 0.0239 inch. Replaced load of 280 pounds. 280 I 0.4849 I | 300 I o 5332 I I 310 Broke on applying strain. Breaking load, 300 pounds. Modulus of rupture, R = = 10,288. No. 48. — Material: Alloy.— Original mixture: 12.5 Cu, 87.5 Sn.— Dimensions : Length between supports, 22"; Breadth, 0.985"; Depth, 0.990". 10 20 40 60 80 100 5 120 140 160 180 200 5 200 220 240 260 270 280 290 300 5 0.0025 0.0050 o. 0141 0.0230 0.0352 Beam 0.0508 7,901.458 • 7, 2 49, I 95 6,330,144 sinks slowly. | 5,482,803 0.0760 0.0969 0.1262 0.1592 0.2044 0.2268 0.2916 o . 4078 0.5210 o.57 6 3 0.6458 0.7185 0.8025 0.0120 0.1238 4,397,784 4,024,116 3,53 J , 2 37 2,725,307 1,639,194 1,207,609 1,041,220 0.6742 j Scale beam rose. In 2 minutes balanced at 20 pounds. In 4 minutes balanced at 29 pounds. In 15 minutes balanced at 34 pounds. Ran back pressure-screw till beam balanced again at 5 pounds. 5 I ! 0.6555 ! •••. Beam rose again, balanced at 12 pounds in 5 minutes. 5 | | 0.6508. | Total decrease of set in 20 minutes, 0.6742— 0.6508 = 0.0234 inch. Beam rose again, but test was continued without further waiting. 260 I 0.8304 I ] 280 o 9018 1 ........ 300 1.0760 Beam sank rapidly. 300 Repeated. Bar broke just as beam rose. Breaking load, 300 pounds. ■xPl j Modulus of rupture, R — -7 = 10, 254. 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 100 pounds gave a deflection of 0.2109 inch, and produced a set of 0.1753 inch. The same load restored de- flected the bar 0.2415 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 0.5 131 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. 501 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 91^ minutes to 1,003, an d m minutes to 91 1 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 1 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 lattet 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 case of the brass above described, it may progress so fa? as to produce rupture, when the load becomes heavy, up t^> a limit, which closely approaches maximum tenacity in the A ; ron 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. I DEFLECTION. SET. Min. Pounds. Pounds. Inches. Inch . 3 0.1091 1,603 0.287 .... 1 1,521 *82 0.287 2 i,493 no 0.287 3 1,483 120 0.287 23 1,463 I 4 0 0.287 53 1,461 I42 0.287 133 i,459 144 0.287 193 i,457 I46 0.287 363 T ,457 146 0.287 363 3 0. 1481 i,457 0.2863 1,603 0.3016 ..... 2,720 2.6400 96.5 993 240 0.5456 118 9 11 322 121 911 1 326 Broke No. 612. — 47.5 PARTS COPPER, 52.5 PARTS ZINC. 800 0.3332 3 0.1478 800 0.3366 5 79° IO 0.3366 25 778 22 0.3366 120 766 34 0.3366 480 756 44 0.3366 1,320 75* 49 0.3366 q 0.1688 7Si ttl 0.3364 800 1. 100 4 y Broke No. 648 Wrought iron. First Trial. Min. Pounds. Pounds. Inches. 1,003 0.0995 3 1,003 0.1031 25 999 4 0. IOOI 100 991 12 O. IOOI 275 987 16 O. IOOI 320 987 16 0. IOOI 320 3 322 987 0.9910 322 1,003 0. 1003 ..... 2,720 2 . 64OO Inch. 0.0049 0.007 Second Trial. I 1,003 | 2.2548 | No. 561. — 27.5 PARTS COPPER, 72.5 PARTS TIN. ...... 160 | 0.0696 • . . c . 5 160 0.072 I *54 6 0.072 3 150 10 0.072 2,640 104 56 0.072 4,140 100 60 0.072 5 100 0.0763 ..... 160 0.0970 ( 320 0.2200 1 O.OI45 O.04 Broke No 599. — 10 PARTS COPPER, 90 PARTS ZINC. *5 1,233 1,137 3 1,137 1,233 1,133 I ,°93 i ,°7° 1,063 1,043 I ,° 2 3 1,003 100 140 163 170 190 210 230 0.5209 0.5209 0.5131 0.5456 0.5456 0.5456 0.5456 0.5456 0.5456 0.5456 0.5456 0.2736 No. 655. — Queensland tin. 100 0.2109 3 0.1753 100 0.2415 70 3° 0.2415 62 3 8 0.2415 56 44 0.2415 100 . . . 0.3033 150 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 1 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- H.M. 504 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. 651 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, O.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 O.O125; 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 0.0001 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 1 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 12 1 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 91 1 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 o. 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 f 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 5 06 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 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 21 hours. This bar, subsequently, was, by a maximum stress of 130 pounds, rapidly broken down to a deflection of 8.1 1 inches. No. 501 presents the finest illustration of this phenomenon yet met with by the Author. The test extended over nearly 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 $ 0 7 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 1 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. HOURS. h:m. J 08 MATERIALS 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. INCREASE. fa W Q Difference. Total. No. 651. — Wrought iron. Load , 1,600 pounds. Min. Inches. Inches. Inches. 0 0.4890 0-5937 0.1047 0.1047 2 0.6197 0.0260 0.1307 3 0.6322 0.0125 0.1432 4 0.6410 0.0088 0.1520 5 0.6473 0 . 0063 0.1583 6 0.6504 0.0031 0.1614 16 0.6598 0 . 0094 0. 1708 .344 0.6598 0.0000 0.1708 Maximum load, 2,589 pounds; maximum deflection, 4.67 inches. No. 504. — 0.557 PARTS COPPER, 99.443 PARTS TIN. Load , no pounds. O 0.323 0.406 5 0.083 0.083 845 1-945 1-539 1.622 865 2.005 0.059 1 .681 895 2.138 0.134 1.815 1,025 2.248 0. no 1.925 1, no 2.378 0. 130 2.055 1,270 2.626 0.248 2.303 Maximum load, 130 pounds ; maximum deflection, 8.11 inches. No. 479. — 96.27 PARTS COPPER, 3.73 PARTS TIN. Load , 700 ponnds. O 0.441 5 0.559 0. n8 o.n8 10 0583 0.024 0.142 20 0.601 0.018 0. 160 TIME. DEFLECTION. INCREASE. Difference. Total. Min. Inches. Inches. Inches. 30 0.618 0.017 0.177 4 ° 0.630 0.012 0.189 5 ° 0.642 0.012 0.201 60 0.650 0.008 0.209 Set 0.524 Second Trial. — Load , 1,000 pounds. 0 3.n8 5 3-540 0.422 0.422 15 3.660 0. 120 0.542 45 4.102 0.442 0.984 75 7.634 3-522 4.506 Broke bar under x,< 000 pounds. No. 501. — 9-7 PARTS COPPER, 90.3 PARTS TIN. Load , 160 pounds. 0 1.294 10 1. 319 0.025 0.025 70 1.463 0.144 0.169 130 1.530 0.067 0.236 310 1.691 0. 161 0-397 400 1.766 0.075 0.472 460 1 .811 0.045 0.517 1,360 2-534 0.723 1.240 i,475 1,565 2.697 0.163 1.403 2.782 0.085 1 . 488 D 730 2.938 0.156 1.644 1,880 3. x 3 6 0.198 1.842 2,780 3.798 0.662 2.504 2,940 4.274 0.476 2.980 3,000 4-349 0.075 3-055 3,295 5-097 0.748 3.803 Bar left under strain at night and found broken in the morning. 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. S°9 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, o H in < w fct< c £ O < 2 < to to CD £ Q. 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. 510 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 (1 5 1 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 91 1 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 0.1 136 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 1 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 YS> 511 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 651 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 100 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 65 1, 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 (10.9 cm.) to 4.67 ( 1 1 .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 y 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 STRENGTH OF ALLO YS. 5 I 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 18 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, 0.09,0.25,0.10,0.25, o. 10 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 33 5 14 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 91 1 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 1,137 pounds 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 CONDITIONS AFFEC TING STRENGTH OF ALIO YS. 5 I 5 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 io 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 13,75° 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 516 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. Dead Load. Live Load. Lbs. per sq. in. Kgs. per sq. cm. Lbs. per sq. in. Kgs. per sq. cm. Copper, cast . 4 8 5,000 352 2,500 176 “ forged 4 8 15,000 1,055 7,500 528 ‘ ‘ wire 4 8 16,000 I G 25 8,000 563 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. [See Appendix for Table of Prop- erties of Metals and Alloys.] 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. 5 I B 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 cherm 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 may be 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 v/ith 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 conception of the compression of fluid metals was probably first introduced by James Wood, a well-known engineer and mill-wright of Lancashire, England. He used this process in making printers’ rolls of copper, 1856-9, at the Broughton Works, Manchester, and at the works of J. Wilkes & Sons, Birmingham. He is said to have shown his method to Sir Joseph Whitworth. 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 of 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 520 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 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 most 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. MECHANICAL TREATMENT OF THE METALS. 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 Cast in the Ordinary Way. Transverse Section of Steel Ingot 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 Lavroff, 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 made 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 525 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 , 1 99 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-T ension 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 . 527 294. 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 : (1.) 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 seribus 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— NON-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. 3 6, 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 inch — 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. S 2 9 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. P'airbairn 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. 29 7. 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 TREATMENI OF THE METALS. 53 1 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 1, 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 ; and the density of a circular piece one-quarter inch, taken across the bore, was 8.595* The increase here noted of 50 percent, 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. According to Volmaer and others, Kunzet was the originator of the “steel-bronzes” and deserves more credit than has been given him. S 3 2 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 1 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 1 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 1 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 * “ Anna les de 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 pared with Krupp’s those of ordinary gun-bronze, as corn- steel for guns, to be — BRONZE. 1 STEEL. Tenacity 2,260 kilograms per square' centimetre (32,092 pounds per square inch). 400 kilograms per square cen- timetre (5,680 pounds per square inch). 15 per cent. 12.5 millimetres inch). 4,800 kilograms (68,160 lbs.). 900 kilograms (12,780 lbs.). 21.4 per cent. 10.5 millimetres (.42 inch). Elastic resistance Extension when broken Hardness (.depth of indenture) 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 “ 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, (7 1 ,937 pounds 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 : I. The work performed by the pressure of the gases of the exploded powder , and destroying the fit of the shot by enlarging the bore , should be performed originally 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. II. 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 to 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 ? 536 MA TE RIALS 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 (1 inch) and 50 millimetres (2 inches) width in the clear, and 25 millimetres (1 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 1 per cent, addition of zinc. 8.5 per cent, bronze, with y 2 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, tha* 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 1 per cent, zinc, to an elongation of 1 5 per cent. 8.5 per cent, bronze and r / 2 per cent, zinc, to an elongatioa of 20 per cent. The results of tests made can be seen in the following table : MECHANICAL TREATMENT OF THE METALS. S3 7 ALLOYS. TENSILE STRENGTH. ELASTIC LIMIT, j ELONGATION WITHIN THE ELASTIC LIMIT IN O.OOOOX. SET IN PER CENT. OF LENGTH. Pounds per square inch. Kilograms per square centi- metre. Pounds per square inch. Kilograms per square centi- metre. 10 per cent, bronze 1 1 mi 5,066 24,140 O R 174 1.5 8 per cent, bronze 73-840 5,200 19,880 1,400 140 2.5 6 per cent, bronze 77-532 5-460 18,460 I , 3 °o 128 3-5 ic per cent, bronze and 2 per cent, zinc . . 42,884 3,020 8,520 600 89 0.5 10 per cent, bronze and 1 per cent. zinc. . . 59- 2I 4 4,170 14,200 1,000 120 0.7 8.5 per cent, bronze and % per cent. zinc. 53 - 96 o 3,800 21,300 1,500 157 i -7 These tests showed that, in general, the io 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 100,000 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 558 MATERIALS OF ENGINEERING— NON-FERROUS METALS. Uchatius seems ignorant. The surface of the die was of welh 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. I, NEAR THE — TEST-BARREL NO. 2, NEAR THE — Bore. Exterior surface. Bore. Exterior surface. Tensile strength per i square centimetre, in kilo grams 4 , 2 5 ° 3,320 4,250 3,320 Tensile strength pe. i square inch, in pounds .... 60,350 I 47»*44 60,350 47, *44 Limit of elasticity per i square centimetre, in kilograms 1,100 500 1,100 700 Limit of elasticity per 1 square inch, in pounds . . Stretch, ultimate, in per cent, of length 15,620 7,100 15,620 9,940 16.5 50 16.5 5 ° Stretck, elastic, in per cent, of length 0.306 0.060 0.306 0.060 Section at the point of rupture, which was orig- inally taken = t.od 0.56 0.50 0.56 0.50 Hardness, depth of indenture, in millimetres 10.6 12 10.6 12 Hardness, depth of indenture, in inches .43 .48 .42 .48 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 1 kilogramme (2.2 pounds), and 238 shots with the normal charge of 1.5 kilogrammes (3.3 pounds). The projec- tiles were 2^4 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)4 diam- eters in length, weighing 6)4 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. 1 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. 54 2 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 is 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, (1) 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.-}* 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 homogeneousness 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, eg ., 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 pressures 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 vis — 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. 54 7 who has ever devoted a mind rich alike in scientific knowledge and in 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 writer^? 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 Ecole des Pouts et Chaus - sees, 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, and Rondelet, in his u 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 “ Essai Tldorique et Experimental sur la Resistance du Fer Forge ,” 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 the original length of the piece in tension. Tredgold, writing in 1823, says: “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. 54 § MATERIALS OF ENGINEERING— NON-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 hist 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, fof MECHANICAL 7 REATMENT OF THE METALS 549 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 1*4 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 550 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 io 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. 55 I 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 (i 873—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 55 2 MATERIALS OF ENGINEERING— NON-FERROU S METALS* force to the amount of distortion by the graphical method, and, in his “Resistance des Materiaax” 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 while 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. 553 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. Internally Cooled Inerot. Cast Ingot. 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 i860. 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 554 MATERIALS 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 dei 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 1 -30,000th inch diameter. Mr. Brockedon, as early as 1819, using the pre- cious stones as draw-plates, produced wire 0.0033 inch in 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 MA TE RIALS 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 16, 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. j n g suggested 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. $57 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 qualities of the useful metals. It may be concluded, from what has pre- ceded, that the proper method of preparation of metal to secure a maximum value is the following: (1.) 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- 558 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. APPENDIX. § 51, p. go . — Aluminium and zinc in the proportions 67 and 33 give an alloy of much value for special purposes. From a series of tests made in the Mechanical Labora- tory of Sibley College, on the strength of alloys of alumin- ium and zinc in varying proportions, the best results were found for mixtures of not far from the above proportion. The principal properties of the metal were found to be as follows : Tensile strength deduced from small bars 22,000 Maximum “ fiber stress” deduced from transverse tests. 44,000 Modulus of elasticity 8,000,000 Specific gravity 3.3 Apart from the above, comparative experiments have been made more recently between small bars of this metal and like bars of cast iron, showing the same general indications, and apparently warranting the conclusion that this alloy is the equal of good cast iron in strength, and its superior in location of elastic limit. The other general physical prop- erties of chief interest are as follows: The color is white and it takes a fine, smooth finish and does not readily oxidize. It melts at a dull red heat or slightly below, probably about 800-900 F. It can, therefore, be readily melted in an iron ladle, over an ordinary black- smith’s forge or other open fire. It is very fluid and runs freely to the extremities of the mould, filling perfectly small or thin parts. In this particular it is much superior to brass. It does not burn the sand into the casting, and hence comes out clean and in good condition to work. It is rather softer and more easily worked than ordinary brass, and yet is not as liable to clog a file. It is brittle like cast iron, and hence is 560 APPENDIX. not suited to pieces which require the toughness possessed by brass. For equal volumes and with aluminium at 50 cents per pound, it is about equal in expense to brass bought at 15 cents per pound. It becomes ductile at 212 0 F. This alloy would seem to be admirably adapted to many small parts of machines, models, etc., where it is desired to obtain castings without waiting for a regular foundry heat, and where lightness combined with good finish, strength, stiffness, and non-corrosiveness, are among the desiderata. It has been employed with great success in the construction of small screw propellers for experimental work.* According to Hunt, zinc is used as a cheap and very efficient hardener of aluminium castings for such purposes as bicycle frames, sewing machines, etc. Proportions up to 30 per cent, of zinc with aluminium are being successfully used ; an alloy of about 15 per cent, zinc, 3 per cent, tin, and 82 per cent, aluminium having especial advantages. Copper in proportions of from 2 to 15 per cent, has been advantageously used to harden the metal in cases where a more rigid metal is required than pure aluminium. Copper is the most common metal used at present to harden alumin- ium. A few per cent, of copper decreases the shrinkage of volume, and gives alloys that are especially adapted for art- castings. The remainder of the range, from 20 per cent, copper up to 85 per cent., give crystalline and brittle alloys of no use in the arts, which are of grayish-white color, up to 80 per cent, copper, where the distinctly red color of the copper begins to show itself. Aluminium brass has an elastic limit of about 30,000 lbs. per square inch ; an ultimate strength of from 40,000 to 50,000 lbs. per square inch, and an elongation of 3 to 10 per cent, in 8 inches. An alloy of 70 per cent, copper, 23 per cent, nickel, and 7 per cent, aluminium has a fine yellow color and takes a high polish, a small percentage of phosphorus in phosphor-tin hardening the alloy considerably. * Science , vol. v., No. 114. APPENDIX. 5 6l Tin has been alloyed with aluminium in proportions from 1 up to 15 per cent, of Sn., givingadded strength and rigidity to heavy castings, as well as sharpness of outline, decreasing the shrinkage of the metal. The alloy Al. 50, Sn. 25, Z11. 25 has a tenacity of 20,000 pounds and 8 per cent, elongation. § 54, p. 95. — “ Magnesium as a Constructive Material ” * is as yet little known, but its properties indicate large possi- bilities, Weighing but two-thirds as much as aluminium, and between one-fourth and one-fifth as much as iron or steel, it seems likely to find uses in the arts, and, like aluminium, par- ticularly in the alloys. The following are its physical constants: PROPERTIES OF MAGNESIUM. Specific gravity Specific heat Atomic weight , Melting point. Boiling point Electric conductivity. . Tenacity per sq. in . . . Compression resistance Bending modulus .... Length sustainable. . . . 1 . 743 (109 lbs. per cu. ft.). 0.2499. 2394- 433° C., 811 0 F. 800 0 C., 1472 0 F. 41.2. 22.000 to 32,000 lbs. 37.000 lbs. 23,750 lbs. 28.000 to 42,000 ft. Its flame has a temperature of about 1,340° C. (2,444° F.), but the light is similar to that of an ordinary flame at three times this temperature. Its radiant light energy is 13.5 per cent. — a higher figure than that of any other known flame, constituting three-fourths its total energy of combustion and four times that of illuminating gas. Its total light-giving efficiency is io per cent., as against one-fourth of 1 per cent, for gas ; and taking into account the greater luminosity of its light rays, it has fifty or sixty times the value of gas. Its spectrum is nearer that of sunlight than that of any other as yet discovered artificial illuminant.f Magnesium is usually obtained by reduction from fluor- * Mainly from paper, by the author, of similar title ; Machinery, May, 1896. f See papers of Professor Nichols and of Mr. Merritt : Trans. Am. Inst. Electrical Engineers, 1890-91. 36 562 APPENDIX. spar with sodium, but it may also be reduced by the electric arc, like aluminium, and it is very possible that, once its valu- able properties and possible applications have attracted attention, it may be produced in quantity very cheaply. It is quite easily distilled and may be thus purified suc- cessfully. The spectrum indicates a close relation between magnesium and aluminium ; both giving bands in the yellow and green, of which those of the former are noticeably duller than those of the latter.* The following are the results of test of the commercially pure metal in form of wire.f The strength here obtained is but about two-thirds tnat given by authorities generally, as quoted above : PROPERTIES OF MAGNESIUM. Specific Gravity , 1.74 ; Melting Point , 446 ° F., 230 ° C. NO. OF SAMPLE. DIAMETER, INCHES. ELASTIC LIMIT, LBS. PER SQ. IN. BREAKING LOAD. DUCTILITY, PER CENT. MODULUS OF ELAS- TICITY. 0-433 8,800 23,800 4.2 2,040,000 0-433 10,780 22,050 1,880,000 3 0.442 8,400 20,900 1.8 2,060,000 0.435 7,090 19,500 2.5 1,830,000 0.424 24,800 n . . 1 1,930,000 J ' A 6 0.432 22,500 2 ^ Average 8,770 22,250 2.8 1 , 945,000 Best figures 10,780 23,800 4.2 2,060,000 Tests of cast magnesium have given results averaging about one-half the above, and ranging from 9,640 to 13,685 pounds on the square inch. The figures given in the table as the best may, perhaps, be taken as those most closely representing the qualities of a pure metal of maximum den- * See a paper on “ Materials of Aeronautic Engineering - ,” by the writer, in Transactions of the Aeronautic Congress, 1893 ; also A eronautics for March, 1894. In these studies all materials were compared by deducing from the data obtained the length of their own substance which each metal could sustain. Steel, for example, when of 75,000 pounds tenacity, would carry about five miles of straight, suspended bar. f Published in the Sibley Journal of Engineering, January, 1894. APPENDIX. 563 sity and purity, and better than can usually be expected in commercial work. They constitute a standard to which specifications may perhaps gradually approximate. The pure metal thus greatly excels pure aluminium in tenacity. Copper and magnesium have not been found to alloy, although much time and labor have been expended in the endeavor to secure such compositions. Brass will take up a minute proportion of magnesium, but with no sensible useful result. The presence of the lighter metal produced neither accession of strength nor increased tenacity. In fact, in every instance the alloy was unsound and weaker than the brass itself. Iron refuses to alloy with magnesium in any sensible amount, and so far as our experiments indicate anything, the magnesium would seem to have no value either as flux or as a strengthening element. Magnesium and aluminium alloy with increase of strength of the resulting composition up to 10 per cent, magnesium, when the alloy becomes brittle and valueless for constructive purposes. The following are figures obtained : MAGNESIUM- ALUMINIUM ALLOYS. NO. OF SAMPLE. PER CENT. MAGNESIUM. LIMIT OF ELASTICITY. TENACITY. MODULUS OF ELASTICITY. 13 O 4,900 13,685 1 , 690,000 14 0 8,700 15,440 2 , 650,000 15 5 13,090 17,850 2 , 917,000 l6 10 14,600 19,680 2 , 650,000 17 30 5,000 A / The addition of magnesium to cast aluminium increases its tenacity by a percentage which exceeds five times that of the per cent, of admixture. The best of these alloys are duc- tile, and can probably be increased in tenacity 50, possibly 100 per cent, by cold-working pure, well-fluxed, and sound sam- ples, and the sustaining power thus carried up to lengths far exceeding those of “ mild ” steel. The only recorded figures for alloys of copper with small doses of magnesium which have come to the knowledge of 564 APPENDIX. the Author, previously to those obtained in Sibley College work, are reported by M. Mouchel, but the composition is not given. The tenacities of these bronzes are substantially the same, it is said, as those found for silicium bronzes in similar form, — that of fine wire. They range from 50 to nearly 100 kilograms per sq. mm., of from about 70,000 to 140,000 pounds per square inch ; where made for elec- trical transmissions— and with conductivities of from 95 to 50 per cent.; but they have been given 10 per cent, higher tenacities when it has been found practicable or desirable to employ alloys of conductivities as low as 20 per cent.* The densities of these alloys are not stated ; but if Mouchel’s compositions change by single tenths of one per cent., the effect of magnesium on copper is obviously very consider- able, both in reduction of density and increase of tenacity. The same authority elsewhere gives the conductivity of cop- per containing one-tenth per cent, magnesium as 94.29^ The following is the table : COPPER-MAGNESIUM ALLOYS. CONDUCTIVITY. COPPER = I. TENACITY. PROPORTION OF MG. LBS. ON SQ. INCH. KGS. PER SQ. MM. 95.16 73,659 51.80 O.OOI 81.60 86,869 6I.O9 2 63.89 106,892 75-17 3 58.01 115,713 81-37 4 51-43 135,767 95-49 5 50.61 108,740 76.47 6 21 . . . 29,862 21.00 ? Comparing magnesium with other substances, on the basis of combined strength and lightness, the length of a prism of uniform cross-section which the metal can carry suspended vertically is probably the best standard ; it was this which was adopted in the paper above referred to in the endeavor * “ Reports on the Paris Exhibition of 1889," vol. iv, p. 233. f Ibid., vol. iv, p. 232. APPENDIX. 565 to ascertain the relative value of metals and other substances for aeronautical construction. Taking the tenacities of mag- nesium as from 22,000 to 32,000 pounds per square inch, it would sustain from 30,000 to 40,000 lineal feet of its own substance, or the equivalent of steel of 100,000 to 150,000 pounds tenacity. The latter is a tool steel and only ex- ceeded by the wire-drawn and rolled steels of exceptional fineness and thinness, which sometimes attain tenacities of 300,000 and even 400,000 pounds per square inch, and are capable of sustaining from 20 to 25 miles of their own material. Machinery now built of open-hearth or Bessemer steel of common tenacities, if constructed of these materials of exceptional lightness and strength, would be correspond- ingly reduced in weight. Thus, the lighter marine engines seldom fall below 200 pounds per horse power; although torpedo-boat machinery and the engines of fast steam yachts sometimes fall to one-half, or even, in rare instances, to one-fourth these figures. Were it practicable to con- struct such machines of aluminium, their weights would be but little reduced. Could they be made of magnesium, the weights would be reduced about 50 per cent. But, on the other hand, could the ultimate tenacity of abso- lutely pure steel in the form of fine wire or watch-spring be used, the weights would become from 50 to 15 pounds per horse power. The maximum molecular tenacity of the finer steels is probably not less than 400,000 pounds per square inch, and when we shall be able to so purify and compact our metals as to attain this maximum, steam engines may be constructed of standard design, similar to those to-day employed, and not exceeding 10 or 12 pounds weight per horse power; and exceptional designs, such, for example, as those adopted by Maxim and by Langley — who have actually introduced the finer steels in strongest forms, and who have already thus brought down the weight of engines alone to 10 and 6 pounds per horse power — would probably give us weights as low as 3 or 5 pounds per horse power. Magnesium has thus no promise of competition with steel, in general construction ; but its place may nevertheless 566 APPENDIX. be very probably found in bearings and cast parts, even where the running parts are steel. It curiously happens, also, that some of the woods may, for such parts as they may be adapted to, compete not only with magnesium and its possible alloys, but also with these fine steels. Professor J. B. Johnson finds tenacities of 20,000 to 30,000 pounds for woods weighing one-twelfth as much as steels, or where strengths and lightness combined are com- pared, having values equivalent to steels at tenacities of a quarter of a million pounds and upward. It is thus evident that until we know more than at pres- ent of the gain to be secured by alloying other metals with magnesium, it can only be said that it seems a possible rival of aluminium. The fact that we find aluminium alloyed with small per- centages of titanium and of other metals, gaining enor- mously in strength, without serious loss of its peculiar light- ness — sometimes doubling its value on the above scale of comparison, and becoming the equivalent of steel of 150,000 pounds tenacity — renders it extremely possible that the same or greater effect may be found to obtain with magnesium, and that one of our most promising fields of investigation is now among its alloys. Both aluminium and magnesium alloys may have important applications in the construction of electro-dynamic machinery. It is known that the con- ductivity of the former alloyed with copper, titanium, and silver, is very high. Magnesium-aluminium alloys containing 10 per cent, mag- nesium resemble zinc, with 15 per cent., brass, and with 20 per cent., bronze. They give good castings and are resistant to the atmosphere, are fairly hard and work as well as brass. The alloys are lighter than aluminium, and while possessing no great strength, are of value for many purposes where a light metal like aluminium would be used, if it could be cast and worked successfully. Partinium is a new alloy of aluminium now being tried for the bodies of motor-vehicles. The aluminium is alloyed with APPENDIX. 567 tungsten, and the resultant metal is said to have a specific gravity of 2.89 cast, and 3.09 rolled ; the elongation varies from 6 to 8 per cent. ; its tensile strength is given as from 45,500 to 52,600 pounds per square inch. It is said to be cheaper than aluminium, nearly as light, and to possess greater strength. (See Wright’s studies of ternary alloys of these metals; Proc. Roy. Soc. of London, 1891-4.) PRODUCTION OF ALUMINIUM. By R. H. Thurston. A remarkable and most simple and beautiful device, how- ever, after a time revolutionized the manufacture of aluminium and through the utilization of this unpromising compound in electrolytic work. This was the discovery or invention, per- haps both discovery and invention, of Mr. Charles M. Hall, at the time a student or alumnus of Oberlin University. This process consists in the solution of alumina in, as he ex- presses it, “ a bath composed of the fluoride of aluminium and the fluoride of another metal more electro-positive than alu- minium ” — i. e., some metal, as sodium, having higher affinities and less easy of reduction than the aluminium itself. It was found that the oxide is freely soluble in cryolite, for example, the natural double fluoride of sodium and aluminium, and still more so when a slight excess of the sodium fluoride is added. In a molten “ bath ” of this double salt, alumina dissolves “ as freely as sugar or salt in water.” A molten mass of cryolite is maintained fluid at its comparatively low melting point and by a voltage which is not far from, in this case, 4.5 volts, and a cur- rent of a dozen amperes. Adding ten to twenty per cent, its weight of alumina, a substance which only fuses at a white heat, the bath, at its low red heat, instantly dissolves it, in spite of the cooling effect of adding so much material at the tem- perature of the atmosphere, and it is seen that the pointer of the volt-meter drops as if freely falling, while the ammeter as promptly shows a rising amperage. The solution is evidently effected instantly. Thus the alumina is dissolved — not melted 568 APPENDIX. or fused, in the ordinary sense' — and, becoming a conductor through this solution, which we may perhaps correctly call the equivalent of a low-temperature fusion, it becomes also an elec- trolyte and can now be decomposed by any current exceeding 2.8 volts intensity. Allowing the decomposition thus to proceed, the dose of alumina is, after a time, exhausted and the voltage rises, as sharply, very nearly, as it originally fell on introduction of the salt, and the amperage coincidently falls off, showing a won- derful sensitiveness in the bath. By continuously supplying alumina, the process becomes a continuous one of indefinite period. No impurities being introduced with alumina or sol- vent, the restoration to the bath of the equivalent alumina, as aluminium is removed, maintains the conditions of its opera- tion constant, and for as long a period as it may be desired to work, or until the introduction of impurities with either the solvent or the dissolved salt compels its purification. Every requirement of successful electrolysis is here pro- vided. The solvent fuses at a low temperature — perhaps about 900 or iooo° F. — dissolving the electrolyte freely, notwith- standing its high temperature of fusion — between 3000° and 4000° F. — and offers such an adjustment of voltages of decom- position of the respective intermingled salts as insures the electrolysis of the alumina first. It is a freely conducting bath, when the alumina is in solution, and a distinctly more resisting fluid when the solution is broken up by the removal of the alumina. Its density is such as to permit the reduced metal to fall to the bottom of the bath, instead of, as would be the fact with many other molten salts, floating it to the sur- face where it would be oxidized, perhaps, as rapidly as formed. The alumina employed in this operation is the native ore “ bauxite ” which may be found in many parts of the world and in large quantities. It is readily freed from its impurities and thus it serves its admirable purpose in this process. Cryo- lite is less generally distributed and is comparatively costly ; but as it is not broken up in this process and only small wastes need be made up, the tax upon the business through the cost of cryolite is small. The low voltage needed in electrolysis of APPENDIX. 569 alumina, once it is dissolved and thus rendered electrolytic, makes the cost of current and of power in this application of energy comparatively small, also ; and the total cost of reduc- tion of the metal on a commercial scale is so moderate that the introduction of this method has thrown out of use all others ; it now makes the aluminium of the world. Even the cost of fusion of the bath and of maintaining it in a fluid state, when the operation is conducted on the large scale of com- mercial production, is extinguished. The heat incidental to the traversing of the bath by the current, and the combustion by the oxygen separated from the alumina, of the carbon anodes of the cells, when the cells are two or three feet wide and four or five feet long, and where there are twenty to forty carbon anodes of 2 \ inches diameter and several inches length below the surface of the bath, is quite sufficient to maintain the bath in fusion and to keep the system in steady operation. By this invention and process, the costs of the metal have been very rapidly reduced. Its price in the market, as one of the rare metals, a few years ago, was several dollars an ounce ; as late as 1885, it cost about $5 a pound and then only in alloy with other metals ; in 1889 it had come down to $1.50 to $2.00, and then, as this new method came into use and developed in magnitude of production, the price rapidly fell, the world over, until, in 1898, it sold in tons at 25 to 30 cents a pound and thus became, volume for volume, a cheaper metal than copper, tin, brass or bronze. The product as rapidly increased in quantity, all finally being made by the alumina process, thus : — PRODUCTION OF ALUMINIUM. Product : Price Date. Tons per Year. per Ton. 1890 40 $5,500 1891 200 2,500 1892 300 1,500 1893 53 ° 1,400 1894 1,200 9OO 1895 1,800 800 1896 2,000 750 1897 2,500 700 1898..... 4,000 600 1900 7>5°° 600 570 APPENDIX . The increasing magnitude of the apparatus of electrolysis has had an important influence upon cost, by reducing wastes of heat and current, and the magnitude of the scale of manu- facture, at the same time, gives economy of production, thus A 50-h.p. plant is producing 1 pound per horse-power, per 24 hours’ work. A 1000-h.p. plant produces 1.4 pounds per h.p., and a 3000- to 6000-h.p. plant produces 1.5, or more. The reduction of conduction and other wastes of current, at such low voltages as are required in this process, tell very powerfully upon economy of operation. Thus, a gain of a single volt now unnecessarily lost, where a total of six volts is employed at each pot, means a gain of 16 per cent, in cost of power, which is the principal item of cost. In many cases these losses are enormous. Purity of product is a peculiarity of these electrolytic pro- cesses. Thus the market pays considerably more for electro- lytic copper than for any other, with the single exception of the native copper of the Lake Superior mines, which is very possibly itself a product of nature’s electrolysis. This purity comes of the fact that no two metals have the same affinities for their electro-negative associated elements. For this reason the current may, in any given case, be adjusted, as to voltage at the terminals of the electrodes, so as to give an intensity intermediate between that voltage required for the separation of the desired metal and that needed for the reduction of the companion elements whenever it is practicable to find an electrolyte in which the desired element stands at the foot of the list in equivalent reduction-voltage. Thus : with a cryolite bath and alumina in solution ; the latter is the lowest in re- quired voltage for electrolytic decomposition, and it is only necessary to so adjust the current as to give more than 2.8 and Lss than 4 volts within the bath to insure the deposition of aluminium ; and, if the bath be itself pure or preliminary pur- ified from undesired elements, absolutely nothing else can be precipitated by the .current. The product should thus be a chemically pure metal, in this case. In fact it is possible, by careful purification of the materials of the bath, to secure a metal 99 per cent, fine, and better. The commercial article is APPENDIX . 57i usually less pure as the raw material is not pure ; but it is pre- ferred with some alloy, as being, for most uses, better ; the alloy conferring upon it increased strength and hardness. The production of aluminium by the electrolytic way is one of the most interesting of all recent innovations in the art of metallurgy, the process being one illustrating a most singularly remarkable method and the product being practically a new material of construction. The industry thus created has rapidly come to be an important division of modern metallurgical production. The arts are by its introduction promoted in many new and unanticipated ways ; a new industry is given the world to add to that diversification which is one of the vital elements of advancing civilization and the discovery of a new application of the electric energies opens the way into a new field of promise for further exploitation by the chemist, the electrician, the metallurgist, the engineer and the con- structor, in many departments of the modern industrial arts.* § 185, p. 305. — Aluminium is displacing copper as a conductor, the product of weight into conductivity and price having fallen sufficiently to give some advantage in its use. Added to steel also, as now practised extensively, the following advantages are said to result : — (1) The increase of sound ingots and consequent decrease of scrap and other loss. (2) It increases the fluidity of steel and allows successful pouring of cold heats. (3) Increases homogeneity a. by preventing oxidation ; b. by alloying rapidly with steel, and thereby increasing the ease with which other metals alloyed with it will alloy homo- geneously with steel ; c. by allowing the steel to remain molten longer and, when solidifying, doing so more evenly. (4) It increases tensile strength without decreasing ductility. * Sibley Journal of Engineering : Proceedings of the Electrical Society of Cornell University, June, 1899. 572 APPENDIX . (5) It takes out oxygen or oxides ; aluminium acting in the same way as manganese. Good steel has been made for elec- trical purposes, using aluminium in place of manganese. (6) It renders steel less liable to oxidation. (7) It furnishes smooth castings. Aluminium is usually added in proportions of from one- fourth to three-fourths of a pound to the ton of steel ; being added either in the ladle or as the metal is being poured. Aluminium combines with iron in all proportions. None of the alloys, however, have yet proved of value, ex- cept those of small percentages of aluminium with steel, cast iron and wrought iron. So far as experiments have yet gone, other elements can better be employed to harden aluminium than iron, and its presence in aluminium is regarded as entirely a deleterious impurity, to be avoided if possible. TENSILE STRENGTH OF ALUMINIUM BRASS ALLOYS. Aluminium. Copper. Zinc. Tensile Strength per Square Inch. I. OO 57.OO 42. CO Pounds. 68.600 I - I 5 55-80 43-oo 70. 200 I.25 70.00 28.00 36.900 1-59 78.00 27.50 42.300 1.50 77.50 21.00 33-417 2.00 70.00 28.00 52 800 2.00 70.00 28.00 52.000 2.50 68.00 30.00 65.400 3-00 67.00 30.00 68.600 3.30 63.00 33-30 86.700 3-30 63.30 33.30 77-400 3-30 63.30 33-30 92.500 3-30 63.30 33-30 90 oco 5.80 67.40 26.80 96.900 Aluminium heated in presence of many oxides reduces the metal from the oxide, and so energetically that Goldschmidt has employed this method in obtaining chromium, magnesium, and other rare metals. The oxide of the metal required is packed, in excess, with finely divided aluminium and, some- times, with sand, and the mass ignited. The combustion which results develops intense heat, and complete reduction of the APPENDIX. 573 oxide follows, with as complete oxidation of the aluminium, and a pure product can be thus obtained.* “ The burning of aluminium as fuel gives us sapphires and rubies in the place of ashes, and metallic fuel is burnt, not by the air above but by the oxygen derived from the earth beneath, as it occurs in the red and yellow oxides to which our rocks and cliffs owe their color and their beauty.” f HEAT EVOLVED BY BURNING ONE GRAMME. f Element. Product of Combustion. Calories. Aluminium 7 > 25 o Magnesium 6,000 Nickel 2,200 Manganese 2,110 Iron L 790 “ 1,580 . ... 1,190 Cobalt 1,090 Copper. 600 Lead 240 Barium 90 Chromium 60 Silver 30 Carbon co 2 8,080 U CO 2,417 Silicon 7*830 § 269, p 477. — At a recent meeting of the Royal Society of New South Wales a paper by Professor Warren and Mr. S. H. Barraclough (M.E., Cornell University, 1895), was read on the effect of temperature on the tensile and compressive properties of copper. The investigation was carried out on some fifty copper test pieces. The temperature range attained was from 25 0 Fahr. to 535 0 Fahr., the temperatures being measured by certified mercurial thermometers. The chief conclusions arrived at were : (a) The relation between the ultimate tensile * Zeits. fur Electrochemie, 1898, iv., 21, p. 494; Sci. Am. Supp., May 20, 1899, p. 19553 - f Royal Institution Proceedings, vol. xvi., part iii. — Roberts-Austin. APPENDIX. 574 strength and the temperature may be very closely represented by the equation f — 32,000 —21 1 , where f is the tensile strength expressed in pounds per square inch, and t is the tem- perature expressed in degrees Fahr. (b) Temperature does not affect the elongation or contraction of area in any regular manner ; and at any one temperature the variation in these two quantities is so variable for different specimens that no particular percentage could be included in a specification for the supply of copper. (<:) The elastic limit in tension occurs at about 5,400 lbs. per square inch ; this limit probably de- creases rapidly with increase of temperature, but the differences in the behavior of individual specimens are so great as to pre- vent the determination of the relationship between the two quantities, id) The elastic limit in compression occurs at about 3,200 lbs. per square inch ; it decreases with increase of temperature, the relationship between the two being more regular than in the tensile tests. ( e ) The rate of permanent extension and compression increases rapidly with increase of temperature. INDEX ART. Alloys 28 aluminium 99, 100 [See Antimony.] Babbitt’s anti-friction 139 [ See Bismuth, Brass.] Britannia metal 126 cadmium and copper 107 characteristics 60 chemical natures 61 classified lists 142, 143 composition, special standard 141 conductivity, electric 68 thermal 67 [See Copper.] crystallization 69 effect of small doses of metal. 135 electric conductivities 68 expansions by heat 60 ferrous copper 196 fusible 1 17 "fusibility 63 German silver 102, 138 gravities, specific 62 grey ternary 265 heat conductivities 67 expansions 66 specific 65 investigations, early 266 iridium and platinum 128 iron, copper and tin 96 zinc 95 and tin 113 iron and manganese 1 27 [See Kalchoids, Chap. VI., Lead.] liquation 64 lists, classified 143 manganese bronze 97, 98, 194, 195 and iron 127 maximum 258-263 mechanical properties 71 nickel and copper 101 and zinc 102 oxidation 70 pewter 120 platinum and iridium , , ... f 128 PAGE 39 178, 180 215 202 186 102 104 226 218-222 120 118 123 212 120 116 319 193 no 182, 215 108 450 118 116 116 451 203 174 174 189 203 113 226 175, 176, 316, 317 203 440-447 126 181 182 124 202 203 I II INDEX ; ART. Alloys, preparation 134 phosphor bronze 192, 193 properties [ See Chap. III.]. recipes, special 142 [ See Resistances.] Spence’s metal 129 specific gravities 62 heats 65 silicon and copper 109, no solders 140 special recipes 142 standard compositions 141 sterro-metals 220 [See Strength, Tin,] thermal conductivity 67 uses 93 [See Zinc.] Thurston’s maximum 258-262 Aluminium 51, 185 bronze 99 uses 100 Analyses 27 and mixtures of copper-zinc alloys 227 Ancient knowledge of metals 1 Anderson’s experiments with gun-bronze 188 Annealing 293 and tempering, effect on density 276 tenacity 277 Anti-friction metal, Babbitt’s 139 Antimony 47 bismuth and lead 122 tin 1 12 and zinc. 125 and copper 104 and lead 118 and tin 123 tin and zinc 124 Appearance of brass, test-pieces 224 fractures 225 bronze test-pieces, external 201 Appendix — Arsenic in alloys 55 Art castings in bronze 136 Babbitt’s anti-friction metal 139 Bar copper 36 Behavior of bronzes under test 202 [See Mechanical Treatment, Resistances.] Bell-metal 189 Bischoff’s tests 185 Bismuth alloys . 116 antimony, tin, and lead 125 bronze 106 and copper 105 fusible alloys 117 lead and tin 117 ores 48 Brass [See Chap. V., X.]. PAGE 210 312-314 221 204 108 Il6 187, 188 276 222 218 368 Il8 172 44O-447 88, 305 178 180 39 376 3 308 526 484 487 215 82 202 188 202 185 196 202 202 37i 373 325 559 95 212 215 59 326 308 303 190 202 187 186 193 193 83 INDEX. nr ART. Brass, alloys tested 223 analysis of mixtures 227 appearances of fractures 225 appearances of test pieces 224 application in arts 87, 90 [See Bronzes.] casting, temperatures 226 classification, Mallett’s 86 comparison of ductilities 244 elastic limits 241 moduli 242 resiliences 240 resistances 239 specific gravities 243 compressive resistance 232 conclusions 245 from tests 239, 245 compositions 85, 227 definitions . 84, 210 ductilities [See Resistances, below\ . . 244 elastic limits 241 moduli 221 experiments, early 219 fractures, appearances 225 foundry 131 [See lvalchoids, Chap. VI.] Mallett’s classification 86 mixtures and analyses 85, 227 moduli compared 242 of elasticity 22 1 Muntz metal 88 notes on tests 230 properties 92 special 89 records of tests 236 resiliences compared 240 resistances compared. 239 compressive 232 results of tests 228 shafts 235 tensile 231, 237 torsional 234 transverse 233, 238 results of tests 228 shaft resistance 235 special properties 89 specific gravities compared 243 Britannia metal. * 126 Bronze [See Chaps. IV., VI., IX.]. abrasive resistance of phosphor-bronze 193 all °y s 72, 74, 197 tested 199 aluminium 99 uses 100 Anderson's experiments on gun-bronze 188 appearance, external, of test pieces 201 fractures 203 behavior under test 202 PAGE 37 ° 376 373 37 i 159, 167 375 159 412 409 411 409 406 412 385 413 379 , 413 158, 376 158, 366 412 409 368 367 373 207 159 158, 376 411 368 160 383 165 161 393 409 406 385 378 392 384, 404 391 387, 406 378 392 161 412 202 314 130, 134,320 322 178 180 308 325 330 326 IV INDEX. ART. Bronze, bell-metal, Mallett’s experiments 189 bismuth 106 [ See Brass.] casting, temperature 200 comparison of conductivities 216 ductilities 225 elastic limits 213 hardness 217 moduli of elasticity 214 resistances 210 resiliences 211 specific gravities 212 compression [See Condensation, below ] 208 resistance of ordnance-bronze 190 conductivities, comparative 216 condensation [See Compression, above]. Dean process 297 Uchatius’ method 298 experiments 299 deductions 300 [See Copper.] Dean’s process of condensation . . 297 defined 72, 186 density 79 ductilities, comparative 215 early compositions 77 elastic limits, comparative 213 elasticity moduli, compared 214 ferrous copper, strength 196 fractures, appearances 203 gravity, specific 212 gun [See Ordnance]. hardness, comparative. 217 Riche’s experiments 191 heat, modifying tenacity 270 history 73 impact resistance of manganese-bronze 195 [See Kalchoids, Chap. VI.] manganese-bronze 97 impact resistance 195 preparation 98 strength 194 maximum, Thurston’s 258 metals used in research 198 moduli of elasticities, compared 214 oriental 78 ordnance 80,187 Anderson’s experiments 188 [See Compression and Condensation, above.] Wade’s experiments 190 phosphor-bronze .... 81 abrasive resistance 193 tenacity 192 uses 82 preparation of manganese-bronze 98 properties 75 principal .... 76 records of tests 204 PAGE 308 187 324 363 361 358 363 361 350 355 355 340 309 "63 530 531 538 540 530 30, 306 141 361 139 358 361 3i9 330 355 363 312 477 131 3^7 175 317 176 316 440 322 361 140 141, 306 308 309 143 314 312 145 176 136 137 335 INDEX . V ART. PAGE Bronze, results final 205 341 resistances, abrasive, phosphor-bronze 193 314 behavior under test 202 326 compared 210, 218 346, 350 I 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 31 1 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 ” 258-262 440-447 [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 VI INDEX . A K 1 • Cold-working metals 294 bronze 310 Dean’s process 297 Uchatius’ experiments 298 deductions 300 iron 309 Lavroff’s process 290 Commercial copper 35 lead 46 metals, prices 59 rare 58 t:n 39 Comparison of conductivity 216 ductility 215 elastic limits 213 hardness 217 methods 302 moduli of elasticity 214 resiliences 211 resistances 210 specific gravities 212 Complex copper alloys 115 Compression, brass 232 bronze 190 strain-diagrams 208 copper. . . 1 71 Dean’s process 297 hardness 16, 217 Lavroff’s process 290 [See Ductility.] malleability 20 non ferrous alloys 157 [See Tenacity.] Uchatius’ methods, experiments, deductions. 298-300 Conclusions, brasses and other copper-zinc alloys 229, 245 kalchoids and copper-tin-zinc alloys 261 mechanical treatment 311 Condensation [See Compression, above]. Conductivity 17 electric 17 of alloys 68 bronzes 216 thermal 17 of alloys 67 bronzes 216 latent heat. 26 Copper and antimony. 104 and bismuth 105, 106 bar 36 and cadmium 107 commercial 35 tests 169 complex alloys 115 compression 171 by impact 1 72 distribution 29 Dronier s alloy of 114 elasticity, modulus 174 PAGE 527 556 530 531 540 555 523 55 81 99 98 66 363 361 353 363 540 361 353 350 355 189 385 309 346 278 530 20, 363 523 27 255 531-540 378, 417 446 557 21 21 120 363 21 118 363 36 185 186, 187 59 186 55 272 189 278 281 42 189 286 INDEX . VII ART, Copper and German silver 102, 138 heat, modifying tenacity 269 history . 29 impact, compression by I7 2 and iron 103 and tin and zinc 113 and iron and zinc 95 [See Kalchoids, Chap. VI.] lead 108 and tin m mercury 114 modulus of elasticity 174 and nickel 101 and zinc 102 properties 34 qualities 30, 168, 174, 176 resistance . . . . 167 compressive 17 1 to impact 172 elastic modulus 174 shearing 170 tensile. . 167 torsional.... 175 transverse 173 shearing, resistance 170 sheet 36 and silicon 109, no sterro-metal 247 tenacity 167 modified by heat 269 tests [ See Resistance, above] 168 commercial copper 169 mean results 176 torsional 175 transverse. 173 and tin [See Bronze]. and zinc 94, 248 torsional resistances 175 transverse tests 173 and zinc [See Brass]. Crystallization 23, 69 PAGE 182, 215 476 42 281 183 189 174 187 188 189 286 181 182 54 43, 271, 286, 287 270 278 281 286 277 276 287 284 277 59 187, 188 4i5 270 476 271 272 287 287 284 172, 416 287 284 3°» I2 5 Dean process applied to bronze 297 Deflection, effect of stress „ 284 [See Resistance, Transverse.] Density, annealing effects 276 bronze 79 [See Mechanical Treatment.] Discussion of experiments on kalchoids 260 Distribution of resistances 160 Droniers alloy 114 Ductilities 20 [See Annealing.] brasses, compared . 244 bronzes, compared 215 hardness 16, 191, 217 kalchoids and other copper-tin-zinc alloys 256 and malleability of metals 20 530 502 484 141 443 258 189 27 412 361 20, 31 1, 363 434 27 VIII INDEX. Ductilities [ See Elastic Limit, Elasticity, Mechanical Treat- ment, Resistances, Strain-diagrams]. Earlier experiments 219 367 investigations 266 451 Early bronzes 77 139 Elastic limits of brass and other copper-zinc alloys 241 409 bronze and other copper-tin alloys 213 348 effect of stress, intermitted 285 508 variable 286 512 exaltation 306 550 non-terrous metals 152 249 Elasticity [ See Annealing, Ductility, Mechanical Treatment]. modified by heat 272 480 moduli for brass and other copper-zinc alloys 221 368 bronze and other copper-tin alloys 214 361 copper 174 286 tin 179 294 [See Resilience, Resistance, Shock.] non-ferrous metals 153 251 proportioning for 155 255 [See Strain-diagrams.] Wertheim’s work 184 300 Electric conductivity 17 21 of alloys 68 120 bronzes 216 363 Engineer, requirements 12 17 Equations of resistance curves 151 248 Exaltation of elastic limit 306 550 Expansion by heat 24, 66 34, 116 Experiments [See Investigations]. Factors of safety 148 244 Ferrous copper, strength I 9 & 3 T 9 Fluctuation of resistance 282 498 Fluxes 5 12 Forging, drop 291 524 hydraulic 292 525 Formulas for transverse loading 162 260 Frigo-tension 3 GI 54 ° Fuels 6 13 Furnace manipulation 133 20 9 Fusibility 25, 63 36, no Fusible alloys 117,120 193,198 German silver 102, 138 182, 215- Grey ternary alloys 265 450 Gun-bronze [See Bronze]. Hammering and rolling. • 3°3 543 Hardness . . . . 16 20 of bronzes and other copper-tin alloys 191, 217 311, 363 [^ Mechanical Treatment.] Heat, annealing and tempering, effect on density 276 484 tenacity 277 487 conductivity 17 21 of alloys 67 1 18 bronzes 216 363 INDEX . IX ART. PAGE Heat, effect of sudden variations 274 482 expansion .... 25 34 of alloys 66 1 16 fusibility 26 36 of alloys 63 110 latent 26 36 modifications of elasticity 272 480 stress 273 481 tenacity of bronze ... 270 477 copper 269 476 various metals 271 480 specific 24 31 of alloys 65 1 16 temperature of casting of brasses . 226 375 bronzes 220 324 effect on strength 278 488 thermo-tension. 293 526 Historical discoveries 304 546 processes. . . 308 550 History of the bronzes 73 131 copper 29 42 experiments 305 548 discovery of the exaltation of elastic limits 308 552 strain-dia.grams 307 551 Hydraulic forging 292 525 Impact, non-ferrous metals 153 251 proportioning for. 155 255 [See Resilience.] Improvements in ternary alloys 257 437 Investigations [ See Metals and Alloys in detail]. Anderson’s experiments with gun-bronze 188 301 Bischoff’s method of test 185 303 early, in the zinc-tin alloys 266 451 Mallett’s experiments with bell-metal 189 308 [See Mechanical Treatment.] Riche on hardness of bronze 191 311 Thurston’s investigations, transverse resistance. 160 258 torsional 166 269 impact on copper .. . 172 281 tenacity of “ ... 173 285 gun-bronze 190 309 copper-tin-alloys . . . 197 320 “ zinc “ .... 222 369 plan of investigations. 249 417 modelof tern ary alloys 252 427 maximum bronzes. . . 258 440 principle (effects of time) 279 489 experiments on ditto 284-285 502-508 U. S. Test Board, copper-tin alloys 197 320 copper-zinc alloys 222 369 copper-tin-zinc alloys 248 416 Wade’s experiments with gun-bronze 187 306 Wertheim on elasticity of alloys 184 300 fridium 56 96 and platinum 128 203 X INDEX. AKi . Iron and copper 103, 196 and tin 96 and zinc 113 and zinc 95 and manganese 127 [ See Mechanical Treatment.] Kalchoids and other copper-tin-zinc alloys [ See Chap. XI.]. Lacquering 145 Latent heat 26 Lauth’s process of cold rolling 296 Lavroff process of condensation. 290 Lead 43 and antimony 118 and bismuth 122 tin 123 and bismuth 125 bismuth and tin 117 commercial 46 and copper 118 and tin ill fusible alloys 117, 120 galena smelting 45 ores 44 and tin 120 Liquation 64 Lustre of metals and alloys 18 Magnesium ' 54 Malleability and ductility 20 Mallett’s classification of bronzes 86 experiments with bell-metal 189 Manganese 57 bronze 97 impact resistance 195 preparation * 97 and iron 127 “ Maximum ” bronzes, Thurston’s .... 258 Mechanical processes 7 P roperties of alloys 71 See Metallurgy.] working of brass 91 metals 8 Mechanical treatment of metals and alloys [ See Chap. XIV.]. cold-rolling, Lauth’s process 296 cold-working 294 bronze 310 iron 309 comparison of methods 302 conclusions 311 condensation, Dean’s process 297 Uchatius’ method, ex- periments, deduc- tions 298-300 Dean process of condensation 297 discoveries 304 drop-forging 292 183 , 193 , 53i- PAGE 319 174 I89 174 203 239 36 529 523 77 196 202 202 202 193 8r 187 188 198 79 78 198 113 24 94 27 159 308 97 175 317 176 203 440 13 126 163 14 529 527 556 555 54i 557 530 ■540 530 546 525 INDEX . XI ART. PAGE Mechanical treatment ; exaltation of elastic limit 308 552 forging 291 524 drop 292 525 hydraulic 292 525 frigo-tension 301 540 hammering 303 543 historical 304 546 history of experiments 305 548 hydraulic forging 292 525 impact 172 281 Lauth’s process of cold-rolling 296 529 Lavroff’s process of condensation. . . . 2 qo 523 qualities effected by 288 517 rolling 291, 303 524, 543 strain-diagrams 307 551 thermo-tension 293 526 Uchatius’ method of condensation, ex- periments, deductions 298-300 531-540 working of metals 8 14 brass 91 163 wire-drawing 295 527 Melting and casting 132 207 Mercury 52 90 and copper, Dronier’s metal 114 189 Metallurgy, calcination 3 9 chemical processes, schedule. 2 5 copper ore reduction 32 47 fluxes 5 12 fuels 6 13 galena smelting 45 79 [See Ores.] roasting 3 9 reduction of copper ore 32 47 tin ore 38 64 schedule of chemical processes 2 5 smelting 4 11 galena 45 79 zinc ores 41 41 tin ore reduction 38 64 zinc smelting 41 41 Metals [ See Index in detail\ ancient knowledge r 3 defined 9 16 useful 10 11 various 183 298 Moduli of brass and other copper-zinc alloys, compared 242 41 1 elasticity of brass and other copper-zinc alloys 221 368 bronze and other copper-tin alloys 214 361 Modulus of elasticity 174 2S6 of tin. 179 294 rupture 163 262 Muntz metal 88 160 Nickel and its ores 49 84 copper 101 181 and zinc 102 182 German silver 102, 138 182, 215 ores . 49 84 37 XII INDEX . ART. PAGE Nickel and its uses 50 86 Odor and taste 21 28 Ordnance bronze [See Bronze]. Ores, aluminium 51 88 antimony 47 82 arsenic 55 gg bismuth 48 83 calcination 3 g copper, distribution 2g 42 sources 31 44 reduction 32 47 distribution, laws of II 17 fluxes 5 12 iridium 56 g6 lead 44 78 smelting galena 45 7g magnesium 54 g4 manganese 57 97 mercury 52 go [See Metallurgy.] nickel 49 84 platinum 53 g2 reduction 3, 4 9, 11 roasting 3 9 smelting 4 11 tin, sources and distribution 37 64 reduction 38 64 zinc, sources 40 40 smelting 41 41 Oriental bronze 78 140 Oxidation 70 124 Pewter 126 202 Phosphor-bronze 81 143 abrasive resistance 193 314 tenacity 192 312 Platinum 53 92 and iridium 128 203 Preparation of alloys 134 210 Prices of commercial metals 59 99 Proportioning for shock 155 255 Rare metals 58 98 Reduction of ores [See Ores] 3, 4 9, 11 Resilience 154 252 of brass and other copper-zinc alloys, compared. . . . 240 409 bronze and other copper-tin alloys, compared 21 1 353 [See Elasticity, Elastic Limits.] proportioning for shock 155 255 Resistance, conditions effecting [See Table of Contents, Chap. XIII.]. brass and other copper-zinc alloys [See Table of Contents, Chap. X.]. bronze and other copper-tin alloys [See Table of Contents, Chap. IX.]. Copper-tin-zinc alloys [See Table of Contents, Chap. XI ]. INDEX. XIII ART. Resistance, Kalchoids and other copper-tin-zinc alloys [ See Table of Contents, Chap XI.]. mechanical treatment [ See Table of Contents, Chap. XIV.]. non-ferrous metals [See Table of Contents, Chap. VIII.]. tin-zinc and other alloys [See Table of Contents, Chap. XII.]. annealing, effect 276, 277, 293 compressive, brass 232 bronze 190, 20.8 chill-casting 275 copper 170 [See Mechanical Treatment, below.] non-ferrous metals 157 conductivity, electric, of alloys 68 bronze 216 thermal 17 alloys 67 bronzes. 216 [See Heat, below.] ductility, brasses, compared 244 bronzes, compared 215 kalchoids and other copper-tin -zinc al- loys 256 elasticity, modification by heat 272 moduli for brass and other copper-zinc alloys 221 moduli for bronze and other copper-tin alloys.... 214 moduli for copper 174 tin 179 Wertheim 184 elastic limits, brass and other copper- zinc alloys 241 bronze and other copper-tin alloys. 213 exaltation 306 non-ferrous metals 152 [See Stress, below.] fluctuation of resistance of bronze 282 fusibility 25, 63 hardness of bronze and other copper-tin alloys. 191, 217 heat, conductivity [See above.'] latent 26 modifications of elasticity 272 stress 273 temperature of casting 278 tenacity 269-271 mechanical treatment [See Table of Contents, Chap. XIV.]. cold-rolling, Lauth’s pro- cess 296 cold-working 294 bronze 310 iron 309 Dean’s process, condensa- tion 297 forging, drop, hydraulic 291, 292 PAGE 484-487, 526 385 309 , 346 483 278 255 120 363 21 118 363 412 362 434 480 368 361 286 294 300 409 358 550 249 489 36, no 3 ii> 363 36 480 481 4S8 476-480 529 527 550 555 530 524, 525 XIV INDEX. • . ART * Resistance, mechanical treatment, frigo-tension 301 hammering 303 Lauth’s process, conden- sation . . 290 rolling 291, 303 Uchatius’ process, con- densation 298-300 wire-drawing 295 resilience 154 brass and other copper-zinc alloys 240 bronze and other copper-tin alloys. ... 21 1 [See Strain-diagrams, below.] rupture, modulus 163 theory 161 safety-factors 148 shafts [See Torsional, below] 166, 235 shearing, of copper 170 shock, non-ferrous metals 153 proportioning for 155 strain-diagrams, brass and other copper-zinc al- loys, tension, transverse 237, 238 Strain-diagrams, bronze and other copper-tin alloys, tension, compression, and transverse. 206, 208, 209 strain-diagrams, kalchoids and other copper-tin- zinc alloys 254 stress, intermitted effect on elastic limit 285 produced by change of temperature 273 repeated, effect on strength 287 steady and unintermitted 284 unintermitted, effect on deflection 283 elastic limit 285 variable effect on elastic limit 286 tempering, effect on density and tenacity. . . 276, 277 tensile [See Tenacity], time [See Stress, above], time of loading, effect 279 torsional, of brass and other copper-zinc alloys. . 234 kalchoids and other copper-tin-zinc alloys 246 non-ferrous metals, alloys 165 shafts 166, 235 tin 180 zinc 182 transverse, brass and other copper-zinc alloys . . . 233 bronze and other copper-tin alloys. 197-205 copper 173 formulas 162 kalchoids and other copper-tin-zinc alloys 246 non-ferrous metals 159 strain- diagrams, brass and other cop- per-zinc alloys 238 strain-diagrams, bronze and other copper-tin alloys 209 time, effects 279 tin 178 PAGE 540 543 523 524, 543 531-540 527 252 409 353 262 259 244 268, 392 277 251 255 404 406 346, 347, 348 429 508 481 5i5 500 502 508 512 484-487 489 39i 414 267 268, 392 294 298 387 320-341 284 260 414 256 406 348 489 292 INDEX . XV wire-drawing Rolling Riche, hardness of bronze Roasting Rupture [See Resistance]. modulus theory Safety factors Shafts, strength of Shearing, resistance of copper Shock, non-ferrous metals proportioning for. [ See Resilience.] Silicon and copper Silicon bronze . . Smelting [See Metallurgy]. Solders bronzes and other copper-tin alloys. Standard alloys. Strength [See Resistance]. [See Resistance.] Temperature [See Heat]. tenacity. Tenacity, annealing effects . . 277 , brass. bronze strain-diagrams. ordnance, Anderson’s experiments. ART. 182 FAGB 29S 295 527 303 524, 543 191 311 3 9 163 262 161 259 148 244 235 268, 392 170 277 153 251 155 255 109 187 no 188 140 216 62 108 243 412 212 355 19 25 I29 204 I41 218 137 214 247 368, 415 150 247 237 404 238 406 208 346 206 344 209 343 254 429 285 50S 273 481 281 492-497 287 515 283 500 284 502 285 508 286 512 158 256 21 28 293 526 276 484 277 487 293 487, 523 I89 308 231 384 237 404 207 344 ■300 530-540 270 477 188 308 XVI INDEX. ART. Tenacity, bronze ordnance, Wade’s experiments 187 strain-diagrams 206 cold-rolling, effects 296 working, effects 294 upon bronze 310 iron 309 copper 167 modifications by heat. 269 [See Compression, Ductility.] forging 291, 292 frigo-tension 301 hammering 303 heat modifications, bronze 270 copper 269 non-ferrous 268 various methods 271 kalchoids and other copper-tin-zinc alloys 255 non-ferrous metals, modifications by heat 268 phosphor-bronze 192 [See Resistance.] rolling 303 cold [ See Cold-rolling, above], strain-diagrams, brasses 237 bronzes 206 tempering, effects 277 thermo-tension 293 various metals, modifications by heat 271 wire-drawing 295 Ternary alloys, grey 265 Tests [See Investigation]. Thermal conductivity 67 Thermo-tension 293 Thurston [See Alloys, Thurston]. Time [See Stress]. Time of loading, effect 279 ‘Tin and antimony 119 bismuth and copper 112 lead 125 and lead. 123 zinc 124 and bismuth and lead 117 commercial 39 and copper [See Bronze]. and iron 96 zinc 94, 248, 262 distribution 37 elasticity, moduli 179 fusible alloys 117 and lead hi, 188 resistance 177 torsional.... 180 transverse 178 sources 37 stress prolonged, effect 280 ternary alloys, grey 265 and zinc .. 12 1, 263, 264 and iron J13 Torsional resistance of brass and other copper-zinc alloys . . . 234 PAGB 306 344 592 527 556 555 270 476 524, 525 540 543 477 470 476 480 430 476 312 543 404 344 487 526 480 527 450 118 526 489 198 188 202 202 202 193 66 174 172, 416, 447 64 294 193 120, 198 288 294 292 64 492 450 201, 449, 450 189 39 1 INDEX . XVII ART. Torsional resistance of bronzes and other copper-tin alloys. . 205 kalchoids and other copper=t;n-zinc alloys 251 259 non-ferrous metals 165 shafts 166, 235 tin 180 zinc 182 Transverse loading, formulas . . 162 time effects 279 resistance, brass and other copper-zinc alloys 233 bronze and other copper-tin alloys. ... 186 copper 173 kalchoids and other copper-tin-zinc alloys. . 246 tin 178 zinc 182 Strain-diagrams, brass and other copper - zinc alloys 238 bronze and other copper-tin alloys 209 stress, non-ferrous metals 159 PAGE 341 419 - 4-12 267 268, 392 294 298 260 489 387 306 284 414 292 298 406 348 256 T Jchatms‘ deductions 300 540 experiments on compressed bronze 299 538 method of condensation of metals 298 531 Wade’s experiments on gun-bronze 187 306 Weights and densities 19 25 Vertheim on elasticity 184 300 Whitworth’s process of compressing steel 289 519 Wire-drawing 295 527 £inc and antimony 124 copper [ See Brass]. and iron 95 and tin 1 1 3 and tin 2^3 history 40 iron and tin 96, 113 metallic 42 nickel 102 ores 41 smelting 41 sources 41 strength 181 stress prolonged, effect 280 ternary alloys, grey 265 tests 182 tin 151, 264 density and strength 265 202 174 174 416 40 *74, 189 73 182 41 4i 4i 296 492 450 297 201, 449 450 Short-title Catalogue OF THE PUBLICATIONS OF JOHN WILEY & SONS New York London: CHAPMAN & HALL, Limited ARRANGED UNDER SUBJECTS Descriptive circulars sent on application. 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Large 12mo, 3 Rotherham’s Emphasised New Testament Large 8vo, 2 Rust’s Ex-Meridian Altitude, Azimuth and Star-finding Tables 8vo 5 Standage’s Decoration of Wood, Glass, Metal, etc 12mo 2 Thome’s Structural and Physiological Botany. (Bennett) 16mo, 2 Westermaier’s Compendium of General Botany. (Schneider) ,8vo, 2 Winslow’s Elements of Applied Microscopy 12mo, 1 HEBREW AND CHALDEE TEXT-BOOKS. Gesenius’s Hebrew and Chaldee Lexicon to the Old Testament Scriptures. (Tregelles.) Small 4to, half mor, 5 Green’s Elementary Hebrew Grammar 12mo, 1 00 50 00 00 75 50 00 50 00 00 00 00 00 00 25 00 50 00 25 19