LIBRARY OF CONGRESS. Shelf ._0-^X UNITED STATES OF AMERICA. ,ov.o'""° »«., FOR Steel Workers ^ / Crescent Steel Co. V^' 136 FIRST AV^^^^^ii^ PITTSBUR6H;f>P^. 26 iB^^ J y / NEW YORK CHICAGO 4S0 Pearl Street 64-e)6 S. Clinton St ^5 ■=*> Copyright 1890, By Crescent Steel Co. ^-3V5 kl q FOSTER ROE 4. CRONE ANNEALING /^ WING to the fact that the operations of roll- ^-^ in.a^ or hammering steel make it very hard, it is frequently necessary that the steel should be an- nealed before it can be conveniently cut into the required shapes for tools. Annealing or softening is accomplished by heating steel to a red heat and then cooling it very slowly, to prevent it from getting hard again. The higher the degree of heat, the more will steel be softened, until the limit of softness is reached when the steel is melted. It does not follow that the higher a piece of steel is heated the softer it will be when cooled, no m.atter how slowly it may be cooled ; this is proved by the fact that an ingot is always harder than a rolled or hammered bar made from it. Therefore, there is nothing gained by heating a piece of steel hotter than a good, bright, cherry 5 ANNEALING red ; on the contrary, a higher heat has several disadvantages : First — If carried too far, it may leave the steel actually harder than a good red heat would leave it. Second — If a scale is raised on the steel, this scale will be harsh, granular oxide of iron, and will spoil the tools used to cat it. It often occurs that steel is scaled in this way, and then, because it does not cut well, it is customary to heat it again, and hotter still, to overcome the trouble, while the fact is, that the more this operation is repeated, the harder the steel will work, because of the hard scale and the harsh grain underneath. Third — A high scaling heat, continued for a little time, changes the structure of the steel, destroys its crystalline prop- erty, makes it brittle, liable to crack in hardening and impossible to refine. Again, it is common practice to put steel into a hot furnace at tHe close of a day's work and leave it there all night. This method always gets the steel too hot, always raises a scale on it, and, worse than either, it leaves it soaking in the fire too long, and this is more injurious to steel 6 ANNEALING than any other operation to which it can be sub- jected. A good illustration of the destruction of crys- talline structure by long continued heating may be had by operating on chilled cast iron. If a chill be heated red hot and removed from the fire as soon as it is hot, it will, when cold, retain its peculiar crystalline structure; if now it be heated red hot, and left at a moderate red for several hours — in short, if it be treated as steel often is, and be left in a furnace over night, it will be found, when cold, to have a perfect amor- phous structure, every trace of chill crystals will be gone, and the whole piece will be non-crystal- line gray cast iron. If this is the effect upon coarse cast iron, what better is to be expected from fine cast steel ? A piece of fine tap steel, after having been in a furnace over night, will act as follows : It will be harsh in the lathe and spoil the cut- ting tools. When hardened it will almost certainly crack; if it does not crack it will have been a remarka- ANNEALING bly good steel to begin with. When the temper is drawn to the proper color and the tap is put into use, the teeth will either crumble off or crush down like so much lead. Upon breaking the tap, the grain will be coarse and the steel brittle. To anneal any piece of steel, heat it red hot ; heat it uniformly and heat it through, caking care not to let the ends and corners get too hot. As soon as it is hot, take it out of the fire, the sooner the better, and cool it as slojyly as possi- ble. A good rule for heating is to heat it at so low a red that when the piece is cold it will still show the blue gloss of the oxide that was put there by the hammer or the rolls. Steel annealed in this way will cut very soft ; it will harden very hard, without cracking, and when tempered it will be very strong, nicely re- fined, and will hold a keen, strong edge. HEATING TO FORGE "T^ ULLV as much trouble and loss are caused b}^ -l improper heating in the forge fire as in the tempering fire, although steel may be heated safely very hot for forging if it be done properly ; but ANY hi(;h degree of heat, no matter how uni- form it may be, is unsafe for hardemnc;. The trouble in the forge fire is usually UN- KVEN HEAT, and not too high heat. Suppose the piece to be forged has been put into a very hot fire, and forced as quickly as possible to a high yellow heat, so that it is almost up to the scintil- lating point. If this be done, in a few minutes the outside will be quite soft and in nice condi- tion for forging, while the middle parts will be not more than red hot. The highly heated soft outside will have very little tenacity : that is to say, this part will be so far advanced toward fu- sion that the particles will slide easily over one another, while the less highly heated inside parts will be hard, possessed of high tenacity, and the 9 HEATING TO FORGE particles will not slide so easily over each other. Now let the piece be placed under the hammer and forged, and the result will be as shown in figure I. The soft outside will yield so much more read- ily than the hard inside that the outer particles will be torn asunder, while the inside will remain sound, and the piece will be pitched out and branded " burned." Suppose the case to be reversed and the inside to be much hotter than the outside : that is, tTiat the inside shall be in a state of semi-fusion, while the outside is hard and firm. Now let the piece be forged and we shall have the case as shown in figure 2. The outside will be all sound and the whole piece will appear per- fectly good until it is cropped, and then it is found to be hollow inside, and it is pitched out and branded " burst." In either case, if the piece had been heated soft ALL THROUGH, or if it had been only red hot ALL THRoiH^H, it would have forged perfectly sound and good. ID HEA'l ING TO F(JRGE FIGURE I FIGURE 2 II HEATING TO FORGE If it be asked, why then is there ever any ne- cessity for smiths to use a low heat in forging, when a uniform high heat will do as well? We answer — In some cases a high heat is more desirable to save heavy labor, but in every case where a fine steel is to be used for cutting purposes, it must be borne in mind that very heavy forging refines the bars as they slowly cool, and if the smith heats such refined bars until they are soft, he raises the grain, makes them coarse, and h^ cannot get them fine again unless he has a very heavy steam hammer at command and knows how to use it well. In following the above hints there is a still greater danger to be avoided : that is incurred by letting the steel lie in the fire after it is properly heated. When the steel is hot through it should be taken from the fire immediately and forged as quickly as possible. " Soaking " in the fire causes steel to become " dry " and brittle, and does it more injury than any bad practice known to the most experienced. 12 HEATING /~\WING to varying instructions on a great ^~^ many different labels, we find at times a good deal of misapprehension as to the best way to heat steel ; in some cases this causes too much work for the smith, and in other instances disas- ters follow the act of hardening. There are three distinct stages or times of heating : First, for forging. Second, for hardening. Third, for tempering. The first requisite for a good heat for forging is a clean fire and plenty of fuel, so that jets of hot air will not strike the corners of the piece ; next, the fire should be regular, and give a good uniform heat to the whole part to be forged. It should be keen enough to heat the piece as rap- idly as may be, and allow it to be thoroughly heated through, without being so fierce as to over- heat the corners. 13 HEATING Steel should not be left in the fire any longer than is necessary to heat it clear through, as " soaking " in fire is very injurious ; and on the other hand it is necessary that it should be hot through to prevent surface cracks, which are caused by the reduced cohesion of the overheated parts, which overlie the colder center of an irreg- ularly heated piece. By observing these precautions a piece of steel may always be heated safely, up to even a bright yellow heat, when there is much fjjrging to be done on it ; and at this heat it will weld well. The best and most economical of welding fluxes is clean, crude borax, which should be first thoroughly melted and then ground to a fine pow- der. Borax prepared in this way will not froth on the steel, and one-half of the usual quantity will do the work as well as the whole quantity unmelted. After the steel is properly heated, it should be forged to shape as quickly as possible, and just as the red heat is leaving the parts intended for cut- ting edges, these parts should be refined by rapid light blows, continued until the red disappears. 14 HEATING For the second stage of he^iting, for hardening, great care should be used ; first, to protect the cutting edges and working parts from heating more rapidly than the body of the piece ; next, that the whole part to be hardened be heated uniformly through, without any part becoming visibly hotter than the other. A I'MForm heat, as low as will give the required hardness, is the best for hardening. BEAR IN MIND, that for every variation of heat, which is great enough to be seen, there will result a varia'jton IN (;rain, which may be seen by breaking the piece ; and for every such variation in tempera- ture, there is a very good chance for a crack to be seen. Many a costly tool is ruined by inat- tention to this point. The effect of too high heat is to open the grain ; to make the steel coarse. The effect of an irregular heat is to cause irregular grain, irregular strains and cracks. As soon as the piece is properly heated for 15 HEATING hardening, it should be promptly and thoroughly quenched in plenty of the cooling medium, water, brine, or oil, as the case may be. An abundance of the cooling bath, to do the work quickly and uniformly all over, is ver^' nec- essary to good and safe work. To harden a large piece safely, a running stream should be used. Much uneven hardening is caused by the use of too small baths. For the third stage of heating, td^ temper, the first important requisite is again uniformity. The next is time. The more slowly a piece is brought down to its temper, the better and safer is the operation. When expensive tools, such as taps, rose cut- ters, etc., are to be made, it is a wise precaution, and one easily taken, to try small pieces of the steel at different temperatures, so as to find out how low a heat will give the necessary hardness. The lowest heat is the best for any steel, the test costs nothing, takes very little time, and very often saves considerable losses. i6 TEMPER THE WORD temper, as used by the steel maker, indicates the amount of carbon in steel; thus, steel of high temper, is steel containing much car- bon; steel of low temper, is steel containing little carbon ; steel of medium temper, is steel contain- ing carbon between these limits, etc. , etc. Between the highest and the lowest we have some twenty divisions, each representing a definite content of carbon. As the temper of steel can only be observed in the ingot, it is not necessary to the needs of the trade to attempt any description of the mode of observation, especially as this is purely a mat- ter of education of the eye, onl}^ to be obtained by years of experience. Likewise, the quality of steel cannot be deter- mined from the appearance of the fracture of a bar as it comes from the hands of the manufac- turer. This appearance is determined, in the 17 TEMPER main, by the heat at which the bar is finished, and therefore one end of a long bar ( and espec- ially of a hammered bar ) may show a coarse, and the other end, a fine grain, where the whole bar will be well suited for the purpose intended. Two tools properly heated, forged and hardened (one from each end of such a bar) will, if broken, show fractures similar in color and grain. The act of tempering steel is the act of giv- ing to a piece of steel, after it has been shaped, the hardness necessary for the work*'it has to do. This is done by first hardening the piece, gener- ally a good deal harder than is necessary, and then toughening it by slow heating and gradual softening until it is just right for work. A piece of steel properly tempered should ALWAYS be FINER in CRAIN THAN THE BAR FROM WHICH I'J' IS NL\nE. If it is necessary, in order to make the piece as hard as is required, to heat it so hot that after being hardened it will be as coarse, or coarser in grain than the bar, then the steel itself is of too low temper for the desired work. In a case of this kind, the steel maker should i8 TEMPER at once be notified of the fact, and could imme- diately correct the trouble by furnishing- higher steel. Sometimes an effort is made to harden fine steel without removing ( by grinding or other method) the scale formed in rolling, hammering or annealing. The result will generally be dis- appointing, as steel which would harden through such a coating would be of too high temper where the scale was removed. This surface scale is necessarily of irregular thickness and density, is oxide of iron — not steel — and therefore will not harden, and is to a cer- tain extent a bad conductor of heat. It should therefore be removed in every case to insure the best results. If a great degree of hardness is not desired, as in the case of taps, and most tools of complicated form, and it is found that at a moderate heat the tools are too hard and are liable to crack, the smith should first use a lower heat in order to save the tools already made, and then notify the steel tnaker that his steel is too high, so as to prevent a 19 TEMPER recurrence of the trouble. In all cases where steel is used in large quantities for the same purpose, as in the making of axes, springs, forks, etc., there is very little difficulty about temper, because, after one or two trials, the steel maker learns what his customer requires and can always furnish it to him. In large, general works, however, such as a rolling mill and nail factory, or large machine works, or large railroad shops, both the maker and worker of the steel labor under great disad- vantages from want of a mutual understanding. The steel maker receives his order and fills the sizes, of tempers best adapted to general work, and the smith usually tries to harden all tools at about the same heat. The steel maker is right, be- cause he is afraid to make the steel too high or too low for fear it will not suit, and so he gives an average adapted to the size of the bar. The smith is right, because he is generally the most hurried and crowded man about the estab- lishment. He must forge a tap for this man, a cold nail knife for that one, and a lathe cutter for another, and so on ; and each man is in a hurry. 20 TEMPER Under these circumstances he cannot be ex- pected to stop and test ever}^ piece of steel he uses, and find out exactly at what heat it will harden best and refine properly. He needs steel that will all harden properly at the same heat, and this he usually gets from the general practice among steel makers of mak- ing each bar of a certain temper, according to its size. But if it should happen that he were caught with only one bar of say inch and a quarter oc- tagon, and three men shotild come in a hurry, one for a tap, another for a punch, and another for a chilled roll plug, he would find it very difficult to make one bar of steel answer for all of these pur- poses, even if it were of the very best quality. The chances are that he would make one good tool and two bad tools ; and when the steel maker came around to inquire, he would find one friend and two enemies, and the smith puzzled and in doubt. There is a perfectly easy and simple way to avoid all of this trouble ; and that is, to write 21 TEMPER after each size the purpose for which it is wanted, as, for instance : Track tools, smith tools, lathe tools, taps, dies, cold nail knives, cold nail dies, hot nails, hot or cold punches, shear knives, etc. etc. This gives very little trouble in making the order, and it is the greatest relief to the steel maker. It is his delight to get hold of such an order, for he knows that when it is filled he will hardly ever hear a complaint. Every steel maker worthy of the name knows exactly what temper to provide for any tool, or if it is a new case, one or two trials are enough to inform him, and as he always should have twenty odd tempers on hand, it is just as easy — and far more satisfactory to both parties — to have it made right as to have it made wrong. For these reasons we urge all persons to spec- ify the work the steel is to do, then the smith can harden all tools at about the same heat, and he will not be annoyed by complaints, or hints that he does not do his work well. 22 FURNACES \ ^ 7E present sketches of a cheap and handy furnace for use in a blacksmith's shop, adapted especially for heating steel, and more par- ticularly for heating steel for hardening. The furnace is so simple that the sketches need no explanation ; for binders, ten pieces of old rail about six feet long with one end set in the ground, and the tops tied by |-in. rods are all that is nec- essary, with a piece of iron about 3x| in. running aroundnearthetop,and setin flush with thebricks. The distinctive features of this furnace are the fire bed and a good damper on the stack. In an experience of many years we have found nothing better than the Tupper grate bar with half-inch openings. These bars set in as shown make a level, permanent bed, and give an evenly distrib- uted supply of air to the fuel. In such a furnace as this, one set of bars will last for years and remain level. While on the subject of grate bars we may as well say that the satisfactory and safe working of this furnace would be entirely defeated by any 23 FURNACES A B END VIEW (uUU-yJ- 5cale : ,1 = I foot. Stack: i?'to2o'hi^h. 24 FURNACES SECTION:A.B. 25 FURNACES attempt to use either square wrought iron bars or ordinary straight cast iron bars. Such bars always warp, get pushed out of place, and allow a rush of air through at one place, and no air at another. This causes hot and cold places in the furnace and produces uneven heating, which is the chief source of cracking in hardening; more- over, the air rushing through the large holes will burn the steel. A bar must be used which will remain level and in its place, and the smaller and more numerous the openings are, the better will be the result. Clean, hard coke is the only proper fuel for such a furnace and for such work. The furnace should be filled full up to the fore plate; or better, a little higher — with coke in pieces no larger than an ordinary man's fist — but the smaller the better. When it is used for heating for forging pur- poses, the damper may be left high enough to run the furnace as hot as may be required — if neces- sary, a welding heat can be obtained. When used for hardening, the furnace should be got as hot as is needed before the steel is put 26 FURNACES into it; then when the steel is put in, the damper should be dropped down tight. The door, which is 12 in. high and 24 in. wide, should be nicely balanced by a lever and weight, with a rod in a handy place so that the operator can pull it up easily and turn over his pieces from time to time, so as to get his heat perfectly uniform. In the clear gas of a coke fire, the whole interior of a furnace can be seen easily, and every piece can be watched as it ought to be. Time, care, watch- fulness and absolute uniformity of heat are the essentials necessary for success in hardening steel. Every large shop should have such a furnace, and should have one man trained to its use, to do the hardening and tempering for the whole shop. Such a furnace in the hands of a careful man in any railroad shop in the country would pay for itself every year and savetheman's wages besides. The furnace will consume very little coke at any time, and when not in use, with the damper down, it will stay hot a long time and waste the coke but a trifle. There is no more absurd nor wasteful system 27 FURNACES than that of requiring a smith at his anvil to harden and temper his work. His fire is not fit to heat in, to begin with, and he never has time to do his work properly if it were. From such a furnace as is here described, we harden all sorts of tools: taps, small dies, large rolls, rotary shear knives, and shear knives as large as five feet long, which is the whole length of the furnace. The tempered steel which is best is that which is the finest in the grain and the strongest. The best way to test both grain and strength is to ham- mer out a piece to about i^xl^ in., a foot or so in length, and temper to a high blue or pigeon wing, and when cold to break it off in little pieces with a hand hammer. A little practice will soon enable a man to de- termine, first, wh'ether he heated his piece to just the right point. The file and the appearance of the grain will determine this point. Next, when a lit- tle experience as to heat has been gained, he will know by the strength and grain whether his steel is really good, or whether it is "dry" and poor. 28 1 FINALLY The art of working^ steel can be acquired only by intelligent application. Some will never learn, and others seem to be imbued with the idea that twenty or thirty years' practice must necessarily qualify them as ex- perts. In point of fact something new can be learned every day, and he is wise who will lay aside prejudice and change his mind whenever occasion requires it. We, as manufacturers, are always pleased to have Steel Workers visit us, and see for them- selves the care and attention given to the work- ing of steel in every department. Crescent Steel Co. 29 LIBRARY OF CONGRESS 014 521 333 2 ,^y '^f^'^i: