The Iron Age 1921-06-16: Vol 107 Iss 24

* co ~ SORE ESTABLISHED 1855 eT VOL. 107: No 24 ta ima a EER LEI, Sik Tonnage-Subordinated. to Getting- Out Forgings of High Quality—Details of Methods Employed and Equipment Used BY SIDNEY G. KOON” ———........, and operated by the Erie Forge Co., the new shops, under the name of the Erie Forge & Steel Co., have.now been purchased by the company from the Navy Department. This is one of the plants developed and built under the emergency legislation of October, 1917, and the importance of its product was so strongly recognized by both the Navy Department (Bureau of Steam Engineering and Bureau of Ordnance) and the War Department (Ordnance office), that in both cases it was classed as a No. 1 plant and every effort made to expedite its completion and its entry into the ranks of delivering producers. Material previously ordered for other places was in some cases commandeered, so that this plant should not suffer delay. A conspicuous instance of this was a 2000-ton hydraulic press originally ordered for the Nor- folk Navy Yard. Another case involved four Westing- house rotary converters which were already on the cars at Pittsburgh consigned to the new Pennsylvania Hotel in New York City, when they were stopped and diverted to Erie, where they have operated ever since. Struc- tural steel had to be taken from other and earlier cus- tomers, and even gravel was obtained in the same com- manding way. Preliminary orders for the construction of the plant were issued Oct. 17, 1917. One month later, on Nov. 17, ground was first broken, and six months from that date, on May 6, 1918, the first open-hearth heat was poured from the first furnace. Before May had ended, the first shaft for the new fleet of Navy destroyers had been forged. The completion of this construction program, which kept 2000 men busy all winter, called for par- ticular care in the placing of concrete and masonry work, because in one of the most severe winters of ‘the past half century much of the work had to be done at temperatures below zero. Such precautions were taken, however, that not a single masonry or concrete failure has been reported. This new plant has been built both with regard to *THeE IRON AGE, New York B st as a war plant by the Navy Department, facility of intercommunication between units and with an eye to future expansion in either direction, west or east. The open-hearth buildiag lies at the north end, with the forging shop immediately south of it, sepa- rated by a narrow court, the machine shop in three wide bays next to the forge shop and the heat treatirg department south of the machine shop. A standard gage shuttle track running north and south near the west end of these several departments is utilized for transferring material from one to another, and the ar rangement is such that the material does not have to retrace its course in any part of its transport. Two open-hearth furnaces, basic lined, and of nominally 60-ton capacity, have already been installed, while space has been reserved for a third furnace within the lines of the present building. These furnaces are frequently charged to 70 or 75 tons when it becomes necessary to make a particularly large ingot or forging. Ingots are poured in a deep pit, some of the molds be- ing as much as 18 ft. high, including the hot top. The largest mold, with capacity for an ingot of 180,000 Ib., is 64 in. inside diameter, 12 ft. 10 in. long, 8% in. thick at top and 16% in. at bottom, and weighs 140,000 Ib. As is usual in forging plants, the molds produce octagonal ingots, or in some cases fluted ingots of a still larger number of sides. Two hydraulic presses, of 2000 and 1500 tons capa- city, built by the United Engineering & Foundry Co., Pittsburgh, and one 6-ton steam hammer, constitute the forging tools. This equipment supplements that at the old works, which includes two hydraulic presses of 1500 tons and 1000 tons capacity respectively, and seven steam hammers of varying sizes. The tonnage capacity of output at the new works is greater than at the old, however, in spite of the fact that only three forging units are available as compared with nine. This is explained on the score of the greater size of the units in the new plant. In the forging department are four soaking pits de- signed and built by Alex. Laughlin & Co., Pittsburgh, each being 13 ft. 9 in. deep, with capacity of 50 tons. Two pits have openings 6 ft. by 10 ft. 6 in.; the other 1595 1596 two, 6 ft. 10 in. by 10 ft. 6 in. Occasionally a piece comes in too long for the soaking pits, in which case it is handled in one of the regular heating furnaces. There are eight of the latter, they being used for re- heating pieces after the first forging and in some in- stances for completing the heating of ingots which have been preliminarily heated in soaking pits. All have furnished by Arthur Stevens, Four of these furnaces are 9 by 15 ft. each, One is 8 ft. 3 in. high. The each, with one door regenerators, and were Chicago. with two doors 44 in. by 47 in. high. by 12 ft., with two doors other three are 9 ft. 9 in. by 11 ft., 0 in. 36 in. by 38 in. by 50 in. high. Great piles of dry sand in front of the heating fur- naces are used for keeping hot the portions of long in- furnace doors by 50 ft., one gots which project outside the Two long preliminary annealing furnaces, 6 ft. being double ended, are located on the delivery side of the presses and are used in the case of some materials, before sending them to the machine shop for rough machining. Practically all of the equipment in the machine shop consists of exceptionally massive tools, mainly lathes. Two of the lathes in particular are more than 100 ft. long, while a third is 88 ft. long. These are used for turning and boring shafting for large naval as well as forgings for naval guns of various sizes and for complete guns of 6-in. bore and smaller. Particu- larly interesting in the work of these long lathes is the vessels, process of trepanning, which will be described later. In general, after a roughing cut has been taken in the machine shop, the pieces are carried into the heat treating room, where they are annealed, tempered or handled otherwise in accordance with the specifications under which they are being built. Very little carbon- izing is being done in the plant, as it is rarely called for. Most materials are shipped out rough machined and without a finishing cut. In the of crank shafts, however, of which large numbers are made for case Ingot press ; be Lowering a Heavy yond is the 1500-ton press THE IRON into Soaking Pit In background, Reheating furnaces are along the wall at left AGE June 16, 1921 Diesel engine use, it is customary to finish the shaft complete in the machine shop, ready to be installed in the assembling of the engine. In the heat treating department are six vertical furnaces all 8 ft. in diameter, five of them 29 ft. long the other 35 ft. long. One large vertical quenching pit measures 12 ft. in diameter and 40 ft. deep. The equip ment, of course, includes necessary grips for this pu pose. In addition six horizontal furnaces for shapes different from the long cylindrica] shafts or gun forgings handled in the vertical furnace These six are all 6 ft. wide, with lengths up to 60 ft. Control of temperatures in the heat treating depart ment is assisted by the usual recording devices of Lee & Northrup make. Material going through these fur naces follows the same carefully prearranged time and temperature schedule as elsewhere in the plant, and thus it is possible afterwards to trace the treatment there are annealiny each piece received. Open-Hearth Department Recognizing, as all steel makers do—but how few act upon it—that the essence of superior quality lies in ample time of operation, the heats in the open-hearth furnaces take 12 or 13 hours from charging to tapping The question of tonnage is held purely secondary to that of the quality upon which the firm’s reputation has been built, and which is guarded with the utmost jealousy throughout all the manipulations of the plant. Orders will not be taken for anything which requires a slackening in the slightest degree of this quality program. Nothing is hurried, everything being run on a predetermined schedule, based upon the experience of years in the turning out of products of the highest quality. This program does not make for tonnage in the way in which that term is understood in the usual steel plant, for a furnace which takes 12 or more hours to do something which could be done satisfactorily for other purposes in 8 hours necessarily loses 30 or 35 per i eee ek Tk directly behind ingot, is the 2000-ton hydraulic forging June 16, 1921 Steel from Stationary Open-Hearth Furnaces Is Poured into These Molds, the Longest Being 18 Ft fut the 12-ft. mold, 64 in. inside diameter, in the insert, has the greatest capacity of them all 180,000 Ib cent of the tonnage which might be turned out under the other set of conditions. The open-hearth plant itself is the outcome of bitter experience of years in attempting to get the quality of ingots for forging which continually tightening specifi- cations were making necessary. So many of these in- gots, purchased in the steel markets, forged down to approximate final dimensions, annealed and rough ma- chined, had to be discarded because of defects shown up only after much money had been spent for material and labor, that finally the management decided that the only remedy was to install a steel-making plant where speed would be wholly secondary, and where the exact quality of product required could be obtained by the most unremitting care in all of the details which in- fluence that quality. Nothing is left to chance. Even the scrap which goes into the making of the steel is selected with the utmost care. Rejection of carload after carload scrap offered has taught the scrap dealers that the re- quirements of the company are particularly rigid, and that nothing which does not meet its requirements in every respect will be accepted. Naturally this scrap has to be low in sulphur because, without the facilities for getting rid of sulphur which an electric furnace affords, the amount of sulphur in the charge takes or an added importance. Oil fuel is used for melting the charge and making the heat. When it becomes about time to tap a heat the melter is as frequently to be found in the adjoining laboratory as out on the charging floor, for the determination of carbon in the melted charge is carried on with chemical accuracy. The ordinary heat melis with about 0.80 per cent carbon—the nickel-steel heats at about 1.50 THE IRON AGE 1597 per cent—and under the continued action of the oxidiz ing flame from the fuel oil, this drops in carbon content with great regularity. When, in the melter’s judg- ment, it has fallen to about 0.50 or 0.60 per cent, a test is taken out and the carbon determined in the labora tory. This takes about 15 minutes. As soon as this report is in, another test is taken out, and thus at in- tervals ot L5 minutes r tnereapouts ucce sive test pieces take from tl irnace, analyzed in the laboratory and recorded n the art of each heat as S 2 vorked. A succes e series of these carbon determination vould ad abo is follows: 0.56, 0.51, 0.47, 0.43, 0.39 0.36, 0 0.29 per cent It is thus evident that, afte irbon get lown in the neighborhood of 0.40 per cent, it lropping from three to four “points” every 15 minute The melter thus has an accurate gage from one determination to the next as to what the fol- lowing one i oing to show. As all heats are caught going down—no recarburizing whatever being done in the ladle, though the necessary ferro-manganese is placed in the furnace shortly before tapping—this method of checking is necessary in order that the heat may be made within the specifications. And all grades of carbon steel, up to 0.90 to 1.00 per cent carbon, are made this way, as well as tool steel and all alloys. When the heat is almost ready for this carbon con- trol, manganese determinations begin to be made at in- ’ 4 & ¢ 4 ~ ernie t saree rw ee ne peepee nagg ses Ril WOR EE eres tn i i i i ai i ee ~ Sime lesia «Taree seein’ ~~ ie ce - ee ae =) = a A IRON AGE Battery of Eight tervals of 30 minutes, and the control of the manganese content of the finished steel is thus a matter of com- parative ease. Nickel determinations in the many cases where nickel steel is to be produced are also made at 30-minute intervals, and any additional nickel re- quired is put into the furnace in the form of solid pig nickel before the heat is tapped. In each such case Eighty-Ton Ingot Under the 2000-Ton Hydraulic Forging Press. from the heat as was the camera In the background at left are the (left) end, actuated from a pulpit as far away June 16, 1921 Horizontal Reheating Furnaces Along the North Wall of the Forge Shop sufficient time is permitted for the homogeneous distri- bution throughout the bath of these various metalloids or alloys. The only things put into the ladle with the steel are a little ferrosilicon and aluminum, to quiet the heat. The same care which has been used in making the steel is continued in pouring it, which is done through a Ingot is turned by the chain supporting its porter bar reheating furnaces June 16, 1921 14-in. nozzle—the size varying somewhat with the character and temperature of the steel. An effort is made in.practically all cases to pour the steel at be- tween 2700 and 2750 deg. Fahr., the temperature being checked by an optical pyrometer. All ingots are top poured. Newly-poured ingots are kept hot on top by means of a hot-top casting lined with refractory material. The riser of the ingot comes up into the hollow casting to a predetermined height, depending upon the placing of the refractory -brick. Hence the hot top within the mold and upon the liquid ingot floats upon the metal and follows it down as it shrinks in solidifying. This avoids opening up a crack or spongy place immediately below the upper skin of the ingot and insures a sound top. This hot top, which includes some 15 to 20 per cent of the ingot weight, constitutes the major portion of the discard under regular specifications. The total proportion cropped varies somewhat from one order to another, but in most of the Navy orders, with which the shop is well filled, the discard at the top is 25 per Vertical Furnaces and Quenching Pit in the Heat Treating Department Are Provided with the Necessary Handling Work in Process cent, with an additional 5 per cent at the bottom of the piece. Ingots are stripped as early as the steel has thor- oughly set, and placed in a large air-tight equalizing pit on the pouring floor of the open-hearth, where they are permitted to soak for several hours without the ad- dition of any external heat, and thus attain a uniform temperature at about 1000 deg. Fahr.—well below the critical stage in the cooling curve. Entering this pit with the still molten interior perhaps 500 deg. hotter than the exterior, the gradual equalizing of the tem- perature avoids the contraction strains which might otherwise be set up near the surface, and thus is pro- THE IRON AGE ‘ 1599 duced an ingot of great uniformity in structure and reliability in working. Reheating and Forging Department When the ingot reaches the oil-fired soaking pits in the forging department, it follows a definite prear- ranged schedule of heating in which the specific tem- perature which it is to have, hour by hour, is rigidly stipulated. As an example, an ingot is brought slowly to (say) 1400 deg. Fahr., and held there for several hours without change. It is then brought up in steps of Appliances for 75 to 100 deg. per hour, to the final forging tempera- ture, after being in the pit a total of some 15 or 16 hours. These schedules are all worked out to avoid strains in the steel while passing through the critical temperature range. Once every hour the temperatures at the top and the bottom of the standing ingot are read by the optical pyrometer—no thermo-couple having been found which would do this work satisfactorily. Record of all these readings hour by hour is placed upon the log accom- panying each ingot in its progress through the pit. This forms a part of the permanent record of the works, by which it is always possible to trace, from the ee ee ee ee 1600 Tool End of Big. Boring Lathe Shown Opposite. only two points of contact scrap which went into the open-hearth furnace to the finished piece a8 it left the shop on the railroad car, just what processes it went through; what tempera- tureg.it was subjected to and what the time-interval was from one part of the operation to the next. ‘pon reaching the large forging press, which was com@™mmdeered from the Navy Department itself, the piec@ again finds a definite schedule of operations await- ing it. A blue-print furnished to the head-pressman shows exactly the amount of reduction to be made be- fore each reheating, while general instructions tell him how much of a reduction is to be made at each impres- sion of the press before the piece is turned around and squeezed in the other directions. Observance of these general directions avoids the trouble so often experi- enced, of opening up the center of the ingot into a four- pointed star-shaped fissure. The reduction is so grad- ual and the piece rotated so frequently that it is im- possible for the fibers to tear themselves apart in the way which accompanies less careful forging. All of the large ingots handled on these two large presses are carried in the usual rotating chain slings by two cranes, one on either side of the press. The sink head which has later to be discarded is used as a porter bar. The operators of the two cranes stand side by side in a fixed pulpit, far enough away to avoid the the heat, but in plain sight of their work. Here they may talk to each other, and thus control their respective cranes in unison far better than would be possible if each were mounted in a cab upon his own crane. For handling smaller ingots, a 50-ton Alliance Ma- chine Co. manipulator, similar in design and operation to the charging machines of the floor type commonly used in open-hearth practice, has been installed at the 2000-ton press. A similar 35-ton manipulator serves the 1500-ton press. These machines grip the piece by the sink head and handle it under the press with the greatest facility, advancing and retreating, turning the pieee over and otherwise manipulating it more quickly than could be done by the cranes. To keep the forging gang busy during the time of transporting materials from the heating furnaces to the presses and from the presses to the annealing fur- nace or elsewhere, one forging gang only is used. These men have nothing to do except to forge the pieces. worst of THE IRON AGE Note stream of compound flowing from bore. June 16, 1921 The steady rests have They do not handle them either into or out of the press department, and hence are shifted from one press to the other as required by the work. This effects a con- siderable saving in cost, because by this means high priced men are kept almost continually busy at high grade work, and are not required to do any of the work of laborers. Much Navy Work in the Plant During the war this plant was in operation night and day on Navy guns of 3-in., 4-in., 5-in. and 6-in. sizes, on crank shafts and other shafting, for destroy- ers, submarines and battleships, and on certain special work such as gun hoops for 12-in. replacement guns for the Navy. All of this: work was alloy steel, the gun forgings being of nickel steel with about 2% per cent nickel. For other forgings a still higher percentage of nickel was used, running up to 3% per cent, and in some cases both chrome and vanadium were employed. At this time two bays of the machine shop were used for shafts and miscellaneous work and one bay for guns. For the latter there were 13 large lathes in use, the rough-turned parts being shipped to Washington, Watervliet, Watertown and various other arsenals and works, for finish machining and assembling. These lathes are now out in the yard awaiting a purchaser. Rapid expansion raised the force of 400 men in the plant to a total of 4000, of whom the great bulk were virtually untrained in this exacting class of work. Only a few of the experienced men were lost to the draft, however, because, being a Class 1 plant under both Navy and Army schedules, the company received the highest consideration with regard to the retention of skilled men in work which was urgently necessary This prevented that disruption of the force which proved so harmful in many other industries. Navy orders still predominate in the plant work, which includes principally gun forgings and shafting. An experimental lot of 6-in. Navy guns, 53 calibers long and forged in one solid piece of nickel steel, instead of being built up from tubes, jackets and hoops, has re- cently been shipped. These “monoblock” guns are 28 ft. long, 26 in. in diameter at the breech and_13 im. at the muzzle. Orders are in the plant for all the nickel steel shafting for five of the six battle cruisers now un- der construction, four of the six super-dreadnoughts: and seven of the ten scout cruisers. June 16, 1921 Especially interesting are the battle cruiser shafts, because of their size and the great amount of power which is to be transmitted through them, and also be- cause of the methods adopted in manufacture, due to the special requirements of the finished piece. Each shaft will transmit upward of 45,000 hp. under full load, which is far greater than the total power of all the machinery on any warship now in service in the United States Navy. Each ship has four such shafts, each composed of three sections—the. propeller shaft, the stern tube shaft and the thrust shaft. These vary in length from 30 to 50 ft., and differ in their outlines, due to the particular service which each has to render. These shafts are forged from 64-in. ingots, 18 ft. long plus the hot top, and weighing 83 tons. In some respects the stern tube shaft is the most in- teresting of the three, because of the fact that both ends are bored to much smaller inner diameter than the middle section. After the shaft has been forged to approximate final diameter (23% in.) throughout the entire central portion, with a much larger diameter re- maining at each end, and the central section rough turned, a hole 1334 in. in diameter is trepanned through the entire length of 39 ft. or more. This results in cutting out an 11-in. diameter core, as about 1 in. of metal is cut away in an annular ring. Mounted on one of the long lathes already men- tioned, the trepanning device does this cutting at about 14 in. per hour, the boring tool turning clockwise as viewed from the boring tool end, and the shaft turning at about the same speed counter-clockwise. The boring is literally flooded with lubricating compound at 100 to 125 lb. per sq. in. This is forced through pipes by means of four pumps located in a separate pump house, and taking their suction from a sump to which all of the used compound drains from the various lathes. After the shaft has thus been bored, it is taken back to the forge department and one end, placed in a heat- Drive End of Boring and Trepanning Lathe, 48 In. by 84 Ft., with THE IRON AGE 1601 ing furnace, is again gradually brought up to forging temperature. Then the thick diameter is forged down in three heats to the same diameter as the center, which is to become the uniform diameter of the entire shaft. This results in closing the hole already bored, to about the size of a broomstick. But as the forging is carried on in very gradual steps, and the piece continually ro- tated during its progress, this hole left in the center is approximately circular in cross section, instead of be- ing irregular and elongated, as would be the case if the material were punished by the all-too-common method of forging in large drafts. Then the other end is treated the same way. Again placed in the machine shop, the end sections are bored to their final inside diameter of 4 in. or 5 in., as the case may be. As this forging is made from an ingot of 60 to 80 or more tons, its weight is depended upon to keep it in place upon the trepanning machine. The shaft has first been rough-turned on the outside to within 44 in. of finished size, so that the coincidence of the axial lo- cation of the trepanning tool with the axis of the piece may be determined with great accuracy. The piece it- self is rotated by a motor at the tail end of the machine, while two or more sets of idler rollers located along its length support its weight and keep it in position. Of course these rollers have to be set with the utmost precision before beginning work. No top rollers are used, consequently the piece is not subject to the con- straint of their pressure, and this is one of the secrets of the relatively low consumption of power in the operation. Savings from this trepanning operation take several forms. In the first place there is reclaimed a large billet or shaft 11 in. in diameter, made of nickel steel, which can either be used for other orders in the shop or can be sold at the high prices which alloy steels command, in place of the scrap price of perhaps $10 per ton which would have been obtained had the boring All Gearing Fully Protected by Screens alee ahaa etna = caekae TOY RY, ah dace ¥. PERE PTE LON RI SHRP IEE SS oe ce Ea ict aay sah vaabciiee 1602 been made in the usual way, leaving nothing but chips. In the second place it is estimated that boring in this manner can be done in one-third the time which would be required for the boring out of the solid material into the form of chips. In the third place the power re- quirements for boring in this form are only about one- third as great as for boring out by the usual means. Particularly important, however, is the use of ma- terial of the utmost homogeneity for the hollow cylinder used for carrying the trepanning tools. In places where this method has been attempted without success, failure was due to the fact that this feature did not receive the consideration it deserved, with the result that the thin, hollow tube, which carries the cutting tools and into which the core is received, could not be kept from buckling, due to the resistance of the work. to say, the same homogeneous quality of material is necessary also in the piece subjected to this treatment. Needless Se eae North Bay of the Machine Shop, Showing Heavy Navy Shafting in Various Stages of Finishing Another interesting shaft under construction at Erie is an eight-throw crank shaft for submarine use, pat- terned after a shaft of similar design found in the cap- tured German submarine U-54. The well known sever- ity of crank shaft service for Diesel engines makes it necessary to provide shafts of the very highest quality of steel obtainable. A side light on this is afforded by a situation existing prior to August, 1914, when Ameri- can makers of Diesel engines, almost without exception, refused even to experiment with American-made crank shafts. This, of course, followed a costly history of breakages and excuses, so that practically all of the Diesel engine shafts used in this country were, for this reason, obtained from Germany, and most of them from the Krupp plant in Essen. Not until the Erie Forge Company had installed its own open-hearth department, and therefore had con- trol of its own raw steel, did the company make a seri- ous bid for this business. Even then, it is reported, more than a year was consumed in efforts to get the business before the first trial order was placed, and for more than a year after that only an occasional order was allotted to the company, the great bulk of the material still coming from Germany. When, however, the company had established its practice with regard to these shafts on such a basis that they could be made THE IRON AGE June 16, 1921 with certainty of result, a successful attempt was made to get the whole of the business of some of the largest Diesel engine manufacturers in this country, instead of only dribblings. As this phase of the situation was reached only a few months before the beginning of the big war, it became possible for the engine builders to get their shafts without interruption, even when im- ports from Germany were absolutely cut off. As a re- sult of this sequence of affairs, it is reported that about 90 per cent of all the crank shafts in the American submarines have come from this company. Specifications for the eight-throw crank shafts called for a tensile strength of 105,000 Ib. per sq. in. on a transverse test piece, with an elastic limit of 80,- 000 1b., an elongation in a 2-in. specimen of 22 per cent and a reduction of area of 50 per cent, and the test piece is cut from near the ingot heart. These figures have been consistently exceeded by about 10 per cent. as = ee ee Cold saw in foreground The maximum results obtained were: 132,000 lb. per sq. in. tensile strength, 100,500 lb. per sq. in. elastic limit, 27 per cent elongation and 65 per cent reduction of area. The shafts are made from a 48-in. ingot, only about 25 per cent of the weight of which is represented in the finished piece as it leaves the shop. Inasmuch, how- ever, as the crank shaft represents from 25 to 33 per cent of the entire cost of the complete Diesel engine, the importance of care in its manufacture is at once apparent. Six of the eight cranks are for the six main cylinders, one for pump and one for compressor. Physical Laboratory and Its Tests Particular attention is paid in the plant to the sub- ject of metallography. A photo-micrographic appara- tus is employed in which all the important heats are studied, both photographically and through the eye piece. As the Navy Department has prepared definite specifi- cations along these lines for a good deal of its work, the use of the photo-micrographs becomes important in keeping to the specifications. This method has been followed still further, however, in analysis of materia! from other sources which has failed to give satisfac- tion in use. In some cases it has been possible to show by this means that the material had been worked too cold for its own good, and thus strained locally. This June 16, 1921 was due in part, no doubt, to an effort to finish forgings with a smaller number of intermediate heatings than they should have received. To teach the operating force something of the re- lationship which exists between quality of steel on the one hand, and the two elements of temperature and time of treatment on the other, a set of photomicro- graphs has been prepared, taken from forging samples subjected to various kinds of treatment. The crystal- line structure of the steel tells eloquently of the stresses to which it is sybjected when wrongly treated, and forms an object lesson which has taught the men of the heat treating department a good deal of the why and wherefore of the strict orders under which they oper- ate. The uniformity of crystals in the product turned out is partly the result of this method of education. Other tests carried on in this physical laboratory include the study of the behavior of material under repeated reversal of stress. This is done in the usual manner, with a piece of small shaft turned down to per- haps % in. diameter, weighted in the middle to a point only slightly below its elastic limit, and then rotated at 1000 to 1200 r.p.m. for several weeks without stopping. The piece on the machine was loaded to a fiber stress of 38,000 lb. on the-sq. in.—a far higher figure than any material receives normally in service—and had al- ready made approximately 99,000,000 revolutions with- out apparent distress. Equipment items in this laboratory include an oil- fired heat treating furnace, four small electric fur- naces for tempering, etc., am oil quenching tank and various calibration devices. For potentiometer work a brick pier is carried up from its concrete foundation, quite independent of the floor and hence of its vibration. A test piece of ordinary carbon steel, shown in the illustration, and which broke with a beautiful cup fracture, gave an elastic limit of 61,000 lb. per sq. in. and an ultimate strength of 91,500 lb. per sq. in. The elongation in 2-in. was 28 per cent and the reduction of area at the fracture was 63% per cent. This was a piece cut transversely across the ingot from which it was taken; the steel had the following chemical com- position: Carbon, 0.46 per cent; manganese, 0.52 per cent; phosphorus, 0.016 per cent; sulphur, 0.026 per cent; silicon, 0.188 per cent. In common with other live organizations of the same character, the Erie Forge & Steel Co. does a great deal of work for itself, such as most manufacturers have done outside. Thus, the electric repair gang not only handles the ordinary line repairs, etc., but does all the repair work on all the motors in the place, even to winding armatures and field coils. An interesting instance of this effort to make the place self-contained so far as possible lies in the laminated-type plate link chains used in the forging shop for handling and rotating ingots during the process of forging. Two of these chains are used for each press, and they were formerly purchased at about $450 per chain, a price which, under the stimulus of the war, soon doubled. These chains had a life of from three weeks to one month, with the former predominat- ing. As the expense was rapidly going beyond reason- able bounds, particularly with the rush of work com- ing into the shop, which was frequently delayed to put in a new chain, an effort was made to form these links of a tough alloy steel which would stand up better un- der the severe service and heat to which they were subjected. Consequently forgings of chrome vanadium steel were made and the links stamped out to size. The first chain thus made has already been in use for two years and appears to have a long life ahead of it. Stores are handled on the very rational basis of or- dering anew at a definite point in the consumption curve. There is a physical separation in each bin in the storeroom, below which are just enough stores of THE IRON AGE 1603 each particular character to last during the period which it will take to get delivery on a new order. As soon as this point is reached, the store-keeper orders the amount of these stores which experience has shown will last for a reasonable period and at the same time can be purchased at reasonable quantity prices. The storeroom clerk, who keeps a perpetual inventory of all stores, is in position to check up constantly on these orders, and if an order does not come through within a day. or so after stores have been brought down, accord- ing to his records, to the danger point, he immediately investigates. This system makes it unnecessary to tie up an undue amount of capital in the storeroom, while at the same time it permits the storekeeper to obtain materials on the best price basis available. The great on Tensile Test of 0.46 Per Cent Carbon Steel Which Showed $1,500 Lb per Sq. In. and 61,000 Elastic Limit Cup Fracture diversity in the stores carried, however, calls for a con- stant supply valued at approximately $150,000. All trackage throughout the plant is of standard gage, thus permitting the shifting of railroad cars to any point where they may be needed. Electric storage battery locomotives are used in transporting material from one place to another, including the hauling of stock charging cars from the open-hearth stock yard onto the charging floor, and the hauling of materials between the open-hearth department, forge department, machine shop and the heat treating building. Because of the moderate depth at which surface water was encountered in the excavations for the build- ing and machinery foundations, a large drainage sys- tem has been put in, entirely surrounding the plant at a depth of some 27 ft. below the ground. This drains out the surface water and keeps it away from the open- hearth casting pit, the regenerators in both the open- hearth and the furnace buildings, and from other places where it would cause damage. Oil fuel storage is provided in six tanks, two of which have 400,000 gallons capacity each, while the other four contain 50,000 gallons each. This total of 1,000,000 gallons capacity is sufficient to last about 50 days when the plant is operating in full. Fuel oil is pumped into the tanks direct from oil tank cars deliv- ered alongside. From the tanks it is pumped at definite pressure to the various points of use. Forging procedure at the plant has been developed largely in the plant by the forge-shop superintendent. The general layout and construction, as well as opera- tion of all the departments and their correlation to each other, are due to the energy of G. W. J. Stout, general superintendent. But dominating each and every activity is the genius of the president and founder, R. F. Devine. ~All these men have practical knowledge of forging problems, from the blacksmith’s forge to the 80-ton ingot; and the men under their charge, taught quality and loyalty at every turn, have had no small share in the growth of the firm’s reputa- tion. 1604 ELECTRIC STEEL IN ALASKA Making Iron or Steel Castings Where Coke Is Scarce and High The following extract from an article by W. E. Cahill, in Mining and Scientific Press, entitled “Elec- tric Furnace Practice at Treadwell,” affords an illumi- nating survey of the possibilities of such a furnace in an unusual locality such as far-off Alaska: “We are one of the pioneers in the manufacture of iron castings by means of the electric furnace; in fact, it is only practised in the East for castings that require a superior quality of metal. With coke at $50 per ton delivered and pig iron at a correspondingly high price, the cost of producing iron in the electric furnace is less than by melting it in the cupola with coke. In cupola melting, the iron, as it melts in passing through the bed of hot coke, picks up sulphur. The action of the blast oxidizes some of the silicon, and introduces gases into the metal. These reactions tend to make the iron hard. This is offset by the addition of pig iron to dilute the sulphur and to replenish the silicon by the excess it contains. “In the electric furnace the action is different. In the first place the iron is melted under a neutral or re- ducing atmosphere. The metal is refined under a calcium-carbide slag, which removes the sulphur even to the limits of that found in steel, whereas the silicon is not appreciably reduced. No pig iron is required, as the metal is softer and stronger than that of the original charge. The chemical composition of the iron is under control; if it be found desirable to raise the silicon or manganese content, this can be done by intro- ducing the ferroalloy directly into the bath of molten metal. The temperature of the iron is under the direct control of the operator. Dull iron is a thing forgotten. There is no rush to keep the iron away from the cupola. The whole charge can be taken at one tap or any de- sired amount at intervals. Little hearth repairing is necessary after an iron heat, from 20 to 50 lb. of magnesite being sufficient for the purpose. In making white iron castings the high temperature attainable makes it possible to pour very thin sections. At times it is necessary to convert part of the remaining charge of gray iron into white iron; this can readily be done by the addition of ore. The shrinkage of electric fur- nace iron is less than that of cupola iron; aside from the merit of purity, its superiority is due in a large measure to the absence of occluded gases. “*Insulation’ is common when starting the furnace on heavy scrap-iron. It often happens that the three electrodes will rest on top of the charge and no cur- rent passes through. A good remedy is to add a few shovelfuls of clean turnings. In extreme cases one can always shovel in some coke, bringing the current over the top of the charge until a steady arc results. “Iron castings are made about three or four times per week, the usual practice being to pour in the morn- ing. Every afternoon we take off a heat of steel—high carbon, low carbon or alloy, depending upon the re- quirements. The melting of cold steel scrap in a cold furnace gave us considerable trouble at first. The melt- ing starts at the top of the pile directly under the elec- trodes. The electrodes gradually work their way toward the bottom. As the steel melts it drops down and strikes the cold magnesite hearth and freezes. The electrodes continue their downward path until a pool of molten steel is formed and the melting of the scrap raises the level of the bath. The course is then up- ward until all the scrap is added. The layer of solid steel on the bottom cannot be melted by keeping the heat on the bath and without overheating or injuring the furnace. The trouble seems to be due to lack of circulation, the hot metal being on the top. This circulation can be insured by the addition of iron ore. which causes the metal to boil, and so washes out the layer of frozen metal. Hematite has proved most satisfactory for this purpose as its action is quick and the effect on the slag is slight. Frequent testing of the bottom with a steel bar is necessary; for, after the steel is free, continued boiling will wash out magnesite, causing slag troubles. THE IRON AGE June 16, 1921 This condition is common when using heavy scrap. When proper scrap is available, the density of the charge may be so arranged that the electrodes will penetrate near to and will heat the bottom. Great care must be used when the scrap is light, especially if the electrodes are penciled, for the pool of steel formed might not be of sufficient depth to prevent the electrodes from boring into the bottom. It is advisable to know the length of the electrode (that is, the distance from the holder to the furnace bottom), so that if the posi- tion becomes dangerous, the current may be reduced until it starts to rise. “Several months ago we had a heat of steel nearly ready to pour, but the power went off and the charge froze in the furnace. A break in the line kept the current off until the next day. By chipping away the slag from under the electrodes we were able to start the circuit. After having the current on the solid chunk for two and a half hours the maximum depth of the pool of molten steel was about 3 in. The furnace was getting very hot so we started feeding ore. When the carbon content became low, pig iron was added. By alternate additions of ore and pig, the steel was finished, and the furnace was poured clean within five hours from the start. “The charging of the furnace influences the melt- ing. Gates and risers make a good charge for the bottom, giving the proper density; and, being at the bottom, the coating of sand does not interfere with the electric conductivity when starting operations. Light scrap is placed on the top and may be piled a foot or more above the doors. A small piece of coke is placed on top of the scrap directly under each electrode. The coke makes a better contact, acts as a cushion, and prevents violent surges of current when starting. The former practice of using hand-control for starting has been discontinued, and automatic control is now used. Peak loads seldom exceed 850 kw., whereas the working load is between 500 and 600 kw. After a steady arc is formed, usually about five minutes after starting lime is shoveled around the electrodes to form the basic slag. Later, as the charge melts, more lime is added. If the scrap melts so as to expose part of the roof to the glare and reflected heat of the arc, it is well to work over some of the light top scrap with a bar, so as to shade the arc and prevent unequal heating of the roof.” [The furnace referred to is a 2-ton Heroult at the plant of the Alaska-Treadwell Gold Mining Co., Tread- well, Alaska. ] Aluminum Pistons for Petrol Engines Data on some experiments on aluminum pistons for petrol engines have been published by W. Von Selve in the Zeitschrift des Vereines deutscher Ingenieure for June 12, 1920. An abstract furnished by Technical Review, London, is as follows: These tests show the advantages of aluminum as compared with cast iron for pistons, owing to their lower specific gravity, better thermal conductivity, bet- ter frictional conditions and their insensitiveness to the effects of air, water, oi] and acids. The comparison extends to aircraft engine pistons made by different processes, the piston diameter in each case being 140 mm. Pressed Cast Aluminum, Alum- Aluminum, Iron Sand-cast inum_ Chill-cast Weight of unmachined piston im B®. .i...s- 6-— 7 3— 3.5 8.0 3.0 Weight of foundry dis- OP. Be bis nc kas 3.0 1.0 1.5 0.75 Faulty castings, per cwt. 10 20 20 5.10 Total metal required, kg. 5 5 10 4 Weight of turnings in machinery, kg. ..... 0.75 6 0.75 Strength of finished pis- ton, kg. per sq. mm.. 18-19 18-20 33-36 20-25 Strength after 10 hours running, kg. per sq. lahat nee Bie. Alek to 18 15-17 26-31 18-19 Elongation at rupture DOR OE. noo sc as cress sa 1 1.5 1— 1.5 Ratio of approximate Price of machined NN 6b Gna wre,s 1 3 6.5 2 The comparison shows that chill-cast aluminum pistons, which satisfy all requirements, are econom!- eally the most advantageous, as the increasing demand for them demonstrates. June 16, 1921 EFFICIENT JOURNAL BEARINGS* Ball and Roller Bearings Compared—Both Superior to Plain Bearings Increased production follows the use of ball and roller bearings correctly designed and accurately made, whether they be used in transmissions, machine tools, motors, rolling mill or other machinery, or wherever heavy work, continuous operation or precision of manu- facture is encountered. Some tests have shown as much as 50 per cent power saving over plain bearings in large factories, but this is exceptional; ordinarily, 15 to 25 per cent is more nearly correct. But the saving, even in small plants, is very appreciable, and is a big help in reducing the overhead. Not only is there a saving in power but, using bearings particularly adapted to the machines, almost continuous operation is insured, and the annoyance of shut downs to reline, adjust or replace plain bearings is avoided. This alone more than compensates for any increase in first cost of application of the anti-friction bearings. Workmen and Lubrication As workmen will not give proper attention to the correct lubrication of plain bearings, great friction develops, the bearings burn and wear out quickly, and generally require renewal at just the time when the mill is busy and wishes to keep machinery operating continuously. Many factories make their repairs over the week end, but this is expensive, and pay of time- and-a-half for Sunday work makes overhead climb. A properly designed ball or roller bearing, packed with the correct lubricant and properly inclosed, will operate at least fifty times longer than a plain bronze or bab- bitted bearing under the same conditions. This makes a big saving, too, in the quantity of lubricant used. Notice the “properly inclosed” above. Oftentimes too little attention is given to the mounting and in- closing of bearings; but they can be so inclosed as to maintain the lubricant for an almost indefinite time, also preventing oil from leaking or dripping onto the floor or onto material being manufactured. Makers of ball and roller bearings specify the lubricant which will give the best results. Graphite and other pulverized minerals should be avoided, as well as greases or oils containing acid or alkali. Pure vaseline, thinned with a pure mineral oil to the con- sistency of cream, makes the best lubricant. With properly designed ball or roller bearings no adjustment is required. They should outlast other parts of the machine, and be made “fool-proof’’—im- possible of adjustment. And the load-carrying capacity and speed of operation of ball and roller bearings ex- ceeds that of plain, bronze or babbitted bearings. Econ- omy in space can often be achieved by replacing plain bearings with ball or roller bearings. Differential Between Ball and Roller Bearings In a sense the ball and the roller bearing each has its own particular field. Yet a correctly designed roller bearing is generally superior to a ball bearing for load- carrying purposes. Because of inherent features of design, a ball bearing is usually best suited to carry relatively light loads at high speeds of rotation. A roller bearing, on the other hand, is superior to the ball bearing for carrying large loads at moderate speeds, and will more successfully carry heavy shock loads. Given a ball of certain diameter, and a roller of the same diameter with its length equal to the diameter, the roller will, for a given load, have a greater surface contact with its raceway than will the ball. The direct compressive stress over this area of contact will there- fore be smaller for the roller than for the ball. Assum- ing a maximum safe working stress, the roller will safely carry a greater load than the ball! at all speeds of rotation, since the drop in capacity at different speeds, due to fatigue stresses, is approximately the same for each. Size for size, made of the same mate- *From a monograph prepared by the Hart Roller Bearing Co., Orange, N. J. THE IRON AGE 1605 rial, and operating at the same speed, the roller bear- ing will, for a stated safe working stress, carry ap- proximately 50 per cent greater load than the ball bearing. On the basis of dollars per pound capacity, therefore, it is evident that a roller bearing is a more economical installation than a ball bearing. As the ball makes contact with its raceway under load, a certain area at the top of tne ball and