The Iron Age 1931-11-12: Vol 128 Iss 20

NEW YORK, NOVEMBER 12, 1931 ESTABLISHED 1855 OUTPUT REGULARIZED DESPITE FLUCTUATING DEMANDS manufacturers are faced with the problem maintaining continuous operations products for which there only intermittent seasonal demand. avoid the necessity sharp fluctuations plant activity meet uneven outflow its products, the Diamond Chain Mfg. Co., Indianapolis, has devised production control system that aims regularize output. tion and purchasing departments coordinate preparing advance schedules that will take care anticipated business without undue danger overstocking under stocking. Sales, produc- The plan, carried out and described this article, has enabled the company reduce production costs, improve the quality its products and insure prompt deliveries customers. SCHLOOT Production Manager, Diamond Chain Mfg. Co., Indianapolis PROMINENT industrial engineer defines pro- duction control means whereby the de- tails connection with production can planned advance and efficiently dispatched, each machine gang enabled work with reference every other machine and gang, the shop manage- ment enabled through advance knowledge provide the necessary elements materials, machines, tools and drawings.” Such program has been adopted the Diamond tion problem. designed control the manufacture chain products, for which the demand intermittent. The models are made for stock, and the sales and production depart- The plan described this article ments are responsible for the inventories carried. Realizing the benefits derived from employing + uniform labor force, our company has taken steps establish uniform production rates for prolonged prod each mod and requiring pproximately irs make. standard rate rmined for each group based ndividual model mprising tha nner some the advantage con model Schedules Are First Set production rates have bee the sales, production and purcl The sales department can purchasing department what able furnish, and the plannir the shop can best build. the tenth each month the sale divisions make out list mod andard grt VOL. 128, No. Cla simular 1 Same nun ot output demand tiy 4 set, the cal hy + ing depar ihat ++ po wna it I be 1223 | and footages each model for the month beginning days hence. These tentative schedules are deter mined after study the inventory and demand for each item has been made. The scheduled quantities the various models within each group must equal the production rate previously established ard. This list models, together with the quantities, becomes “suggested shop analyzed the purchasing department for materials and the production department determin whether the quantities desired exceed the machine too and whether the combina- tions lend themselves economical production. and personnel possibilities This analysis must thorough, because after uggested shop actually accepted, be- comes the production department’s responsibility deliver the items within the period specified. After the “suggested shop order” has been revised the atisfaction the sales, purchasing and production departments, rewritten final. Following receipt the final shop order, the production depart ment calculates the quantity raw material ary complete the order and the requirements are forwarded the purchasing department the form order purchase the stock. As material is received from vend rs, each item is shipment number and tested both for phys- cal and chemical qualities, the results being com- pared with standard specifications. Perpetual inven- tory cards are carried shipments and the records adjusted each test completed. This method 1224—The Iron Age, November 12, 1931 7 ? ONTROL boards are used ma- chine control man for scheduling work machines. One side serves layout departments, each machine being represented half-inch cube pinned the board. Second side board used machine load. Opposite page) control sheet the index sheet extreme left lists indi- vidual machines various departments. Each vertical ruling represents calen- dar day, each horizontal ruling ma- chine listed index sheet. both sides board are wooden spools mounted bearings and carrying rolls tracing vellum paper. Across top each vellum sheet the calendar days are numbered from left manently located silk line extends from top bottom board. Each day the vellum moved one space from right left that line repre senting current day appears under silk cord. adjustment makes possible the maintenance ac- curate stock records without the necessity period- ical physical inventories. Perpetual Inventory System Aid Another advantage the fact that the perpetual inventory system allows the identity the stock maintained from the time leaves the raw stores department until completely fabricated, that any difficulty heat treating parts can and, necessary, the troublesome material seyregated. account the rigid inspection incoming materials, seldom becomes essential dis- card entire shipments after they are partly processed. With the variation analyses and physical properties steel coming from the mills, however, not unusual for lot require different hardening procedure from standard. such cases that the benefits maintaining shipment identities storing and processing are realized. While actual buying materials rests with the purchasing department, the planning department nowise released from its responsibility for seeing that raw stock hand the time needed. Machine tools, well raw materials, must available sufficient quantities the proper time; therefore, control tools essential function the production department. record all tools kept “tool inventory sheet,” which not only serves perpetual inventory, but also provides such data are necessary ordering tools. shows (1) tool | ne 1 petu if te gore J 4 Ge in LOC | lo CO fo t} ; — life, (2) chains parts made with the tool, (3) chain schedule, (4) per- petual inventory, and (5) quantity order. Tool Inventory Important Factor 7 The following steps are taken providing the tools necessary fab- ricate shop order: List schedule each chain using the tool. Total above schedules. Extension terms tool life determines number tools complete schedule. necessary Determination additional tool required over those stores, process and order. Follow-up insure delivery. Tools made the company’s own ma- chine shop are dispatched the planning department the same manner regular pro- duction the shop proper. should noted that the in- ventory tools the total those stores and use. The ordering tools per schedule permits the inven- tory fluctuate with the schedule, and cases reduced schedules closing out certain models al- the inventory reduced ac- cordingly. + ] i( After provision has been made for tools and materials, the next step plan and dispatch the shop order. The first thing decide the order and dates assembly the va- rious lots chain manufactured. view the fact that this program determines the making component parts the assemblies, undertaken with precision. order of must ideal assembly schedule one requiring con- stant labor supply and machine load the manufac- turing departments and incidentally does not set any condition which other ords, arrangement the work which per- mits the shop order delivered time with minimum effort and considered are: cannot overc main factors expense. Machine capacities Available tools Fewest possible machine setups Available labor Uniform demand labor all departm Uniform output scheduled groups and accordance with standard production rate Early production low inventory lels Since parts are made and chain assembled standard lot sizes which may may not equal day’s quota, the rate planned assemblies kept bal- scheduled arrange- ance maintaining the cumulative amount equal the cumulative quota. While the ment assembly program outlined might seem difficult, the planning division soon learns where “the neck the bottle” located and therefore can avoid ] congestion. Desirable combinations are developed — that the knack visualizing the tuati quired. Control Sheet Coordinates The next step find out what parts are made and the dates when the operations each part are completed. This done mear control sheet, which filled for each lot chai assembled. The vertical spaces the sheet for record one day’s processing time. With the finishing date (as shown the the starting point, the work traced backward through assembly, allowing sufficient time perform the different operations. The day before ‘ ee ee ** \ start, the component parts must finished is traced back thro igh tne vario with the laying off for each operation many vertical department succeeding operation the latter sik requires days perform. the top the sheet the planner starts with the assembly fini working calendar days far back operations show the sheet. The date operation corresponds the above. It is readily en same vertical case each operation finished time fear that the schedule will not met. al Lila Work process reduced minimum keep ing parts out production until the item actually needed. various operations are completed, line drawn through the symbol that the control sheet The Iron Age, November 12, — ¥ | PPX | | § ~~ YC = er I tals hat HAT parts made | - + + + + + + + + + + + + + + hows the status jobs all times addition due main support, however, pivoted that the entire dates system free revolve complete circle. For each lot part material requisition and receiving tracer tags with operation due dates, are made up. Dates shown the machine control man determines what ma- ontrol sheet are written the tracer tags and the chine machines the part run and when aper turned over the machine control man run. Under circumstances should this lispatching (scheduling the machines). aid date later than that appearing the task, machine control boards are Having decided when and where the lot run, posts the vellum sheet opposite the machine Machine Control Board Supervises Operations nachines selected and under the date shown the provided for each the top the sheet the following data: part lot, rves layout ts, quantity, standard hours required and the operation ing represented draws horizontal yellow line from the finishing the fac date the left, distance equal the hours neces hat the hours which are taken and therefor for, and limitat available for other work, and when the then filed part number until needed. Prior the time when the job begin, man takes the paper from the file and send vert the requisition and follower tag the stores room the material. the same time machine rder and gage requisition are made out, the former ru A . . ‘ 1 For Part No Date Due Board Units Lot No. 0233 eT l l re nun re I 1 Dept. No Mach. No Deliver to Dept Deliver to Mach. Amt. Rej. | Amt. Ace Price ( tron the » ft t Description Quantity Total Delivered Value ) “J cn Tne ‘ ved oO pace from right to left si 865) hat the line presenti! tl curre! _Prod. Dept. _Stores Dept Bia No Time Started Time Finished appears under the ilk cord ounterbalanced and can raised upport with range deg. 1226—The Iron 1931 November Material requisition made out for each lot parts C) Form «2 6M 9 27-23 ©) ' Chain Na, — Footage | t im rorm ar PART STOCK LEDGER QUANTITY (SSUEO ERPETUAL inven DATE QUANTITY stock cards. being sent the department supervisor order essential information which given below: change the machines the new part and the latter the central gage room. The gage room keeper gets Mate roon Material Machine started Quantity each job hed Status of edul = \ The main problem is to keep the red lines even vith the vertical silk cord. When job finished, inspected and moved the shipping stock depart- ments, report its movement sent the produc TRACER TAG tion department. This information serves “ma showing that the job the floor available for ATES when work dispatching the manner heretofore described from the central planning depart — - tags which are turned ment iy On primary equipment: nat 18s, no over machine con- attempt made schedule operations, such tum trol man for schedul 4 HL _§-8 - required i hort. In - that th mat nished department supervisors for their guidance done When remembered that parts process are kept miniry rY nd that the i1ohs re ntrall i B-\2 Al ch Lila JO alt entra CUl trolled their primary operation and first operat can that there ++ + rtr nts p rformil Parts Storeroom for Final Assembly together, inspects them see that they After has been completed, part good condition, and places them in a container until are transported t the parts tore } m. elgned for. and the amount finished recorded the tay preparation gages advance eliminates page 1281) delay setting new When the job ready for work Burk Dept Machines Listed Below start, the change order returned the planning department and the machine board indicat Oper Finished Parts Are Listed Daily Daily reports are sent the plar ing department the producing de- partments, listing the quantity part finished. The schedule man then marks red over the yellow load line the time equivalent the work completed check the red lines against dates the top the vellun the status each mac group machines. this way, the l 1: nine ot Machine change order sent schedule man department supervisor order control board shows all times the change machines new part prior starting new job The Iron Age, November 12, 1931—1227 | DIAMOND CHAIN CO. ] KIND i} 1} | 1 | | —} Set Made by Date aa — 7 I : — | RESS which brake drum formed, this view having been taken prior installation the machine. NVOLVING the use large press and continuous, gas-fired the brake drum mad the plant Lincoln Motor Car ffords ample deep rawing heavy sto mass-production basis. high-carbon, high-manganese steel plate thi Blanks liameter are used are heated and then are formed the ap- the press. The press weighs 125 tons and will ert pressure 1000 1500 tons. For forming brake drum the press equipped inch die, the having cylindrical hole the larger than the finished hot blank positioned the press over this die and the punch ends and forces through the die, forming the lange the drum against the sides the hole the ram and punch are forced down back- geared cranks and the length stroke the press fter contacting the hot blank, in. carry blank through the die the ejecting position clamping cushion actuated compressed air keep the blank from slipping while forming 228—The Iron Age. Nor ember 12. 1931 FORMING BRAKE NEALEY American Gas Association, New York blanks for making brake drums forthe Lincoln car performed gas- fired furnaces operating the continuous principle. The blanks are formed the approximate final shape single opera- tion the press. absorb the blow the ram pneumatic die cushion attached beneath this press, for the purpose in- creasing the life the parts and avoiding early breakdown. deep under the press accommodate this part the equipment. The pneumatic die cushion feature which has been introduced for metal-drawing work, single-acting presses, pro- vide uniform pressure all sides the blank. also reduces excessive strain the press from high tension the end the stroke. installed the press described, the die cushion fastened the press means four suspension rods attached the web the press. Usually this cushion is.attached the underside the press bed, but may fastened the bolster plate. pressure pad bottom against the underside the press bed was special requirement this case. There also center knockout, which strips the formed blank from the punch and, the punch comes the end its stroke, the formed drum pushed out from under the die for delivery through slot the back the die. The die and punch are lubricated with heavy cylinder oil and the punch water cooled. For making these brake drums the press served the discharge end the furnace short roller conveyor running direct the press. gas — |) | na rou thr Lut il vit na Il} 1d he 7 J a 4 4 L pri rut t DRUMS FOR LINCOLN CARS 4 operator with tongs takes hot blank dis from the furnace and ller conveyor directly into the men will turn out 400 brake drum pressings single shift hr. harged rlige + guides lt aown pres Designed for continuous use, the furnace sen operation and constructed insulated and encased steel. ft. long, ft. high and ft. and heated vith seven gas burners each side, below the hearth, the heat rising ides and behind baffle wall foot high, constructed refractory material. The heat rises until strikes the arch, where reflected and wide, around radiated down tne work. ol separate manifold supplies gas each group seven burners and each manifold provided with inspirator. Gas supplied lb. pressure and air inspirated any proportion give reducing, oxidizing neutral fuel flame within the furnace. this case neutral flame necessary, prevent oxidizing the surface the blanks. Once set, the gard volume work going through the heat removed through take-off flu end, and exhausted through hood the outside the building. iped with short legs through the furnace grooved rails Piece Iron pipe iitable diameter to lide these rails, and ghtly greater than the diameter the blanks heated, are placed the rails, one each side, and drum blank laid these pipes. Upon this blank placed pronged cir- ‘ular ring alloy casting which acts spacer, and hich another blank placed. Blanks are stacked our high, thus providing space between the hearth and the first blank and between the blanks themselves for uniform circulation the fuel flame, which-speeds and materially aids uniform heating. door ace (Cone ded on page prior forming into brake drums. This temperature and heating pericd. Below) Pneumatic cushion installed under brake drum press, suspended from the = = The Iron Age, November 12, 1931—1229 \ - | F q q When stack blanks ready, the MACHINING THE SADD Associate editor vale Co., Nicetown, Philadelphia, for saddles seat the Hudson River cables were shipped, the shipping weight for totaled 2,874,290 lb. This makes average just under 90,000 lb. the casting, and little more than 359,000 addle, consisting our Machining these castings w: an outstanding per formance not only because the great size, but also, unusually tole rances demand d by the Port of New York re and more particularly, because thority for some the surfaces. Except for the grooves the surfaces were all plan But inasmuch these plane surfaces large extent had come within few thousandths inch being per- fectly flat, the problem involved considerable the first half the article described method molding and casting these large units, gether with the subsequent operations cleaning and annealing. When came machining, however, number unusual expedients were adopted making use existing equipment insofar this was possible. doing this some novel methods were evolved which are briefly described herein. cast, each piece had the rough contour the ultimate cable grooves cast it. This was for the SIDNEY KOON THE IRON AGE large problems were involved machining the cable saddle castings for the George Wash- ington Bridge New York over the Hudson River. One had with meeting exceptionally close tolerance over the joined surfaces and the base the enormous structure. The other had with finishing the grooves for the successive strands the cable definite arc circle 30-ft. radius, and again within tolerances measured thousandths inch. These were done the Midvale Co. through the use certain special and partly improvised equipment. purpose minimizing the amount machining this part the surface. These grooves fit the lower half the cable passes over the saddle, and the cable this point the are circle with radius center cable ft. Thus, with 36-in. cable, the bottoms the grooves have radius After the castings were thoroughly annealed they were set plane table and subjected careful ENERAL elevation saddle four steel-castings, aggregating long and ft. in. wide. The cable passes over the saddle with 30-ft. radius center cable. Slots top saddle are for carrying some the cable spinning gear. left) Detail finishing cut one the grooves for the cable These were all finished template. a ™ 1230—The Iron Age, November 193] me G J | aly nul nre as fro the | l | } ® | >> \ Y | CASTINGS FOR HUDSON RIVER BRIDGE CABLES easurement ascertain how much material would ave removed from the base leave the mini safe amount metal the cable grooves for ma- hining (about in. was left). explained the vith the ultimate base the top the mold. This for the purpose putting the densest part metal the working surface the cable grooves. left considerable volume metal removed from the base the casting, and made possible below the blow-holes which are likely appear the top surface any steel casting. Having thus ascertained the extent cut made the base, roughing cut was made all over the base means circular face mill about ft. diameter, using inserted teeth high-speed cable groove means rose miller. illel the final finishing cut and could for machining the ends the cast the exceptionally close fit demanded from casting. ends were turn rough cut means the ipid operation the big circular next operation the castings were placed upon planer and the ends given the finish cut, ing them joined casting against casting nusually close fit. These surfaces were required pectors finished limits within very andths inch. came putting the finish the base tings was required that this done the od The Iron Age, November 1931—1231 ba | 4 be preceding article, the casting was made upside down, ing same For a pern to al hy the i he - found, however, that the ways the planer could not safely loaded more than about 150 tons cast- ing weight. Hence, three the castings were set the planer for the finishing cut. After this had been completed the three, the end casting the three was removed and the casting for the other end 232—The Age, November 12, 1931 LANING base three castings sim- ultaneously, repre- senting nearly 150 tons. was put place. Then this was finished the same tolerance the rest and with the same long base which measure. may mentioned that the base the saddle measures ft. the end sec- tions are, respectively, ft. long and in. long, the surface machined one time measured ET-UP three the castings 12-ft. planer for pur- pose finishing base. The ends these castings have been completed and drilled, shown, bolts holding them together. The grooves here shown are cast the material: they have not yet been machined. | 4 | . hol j SS Circular face mill for making roughing cuts castings. — = Fifty high-speed steel tools are inserted near the periphery (At Right) Taking roughing cut the grooves for the cables. This cutter mounted traveling carriage groove base traverses the face the work. the one case, and just under ft. the tner. After the end joints had been machined and had sed inspection they were drilled with about les for the connecting bolts. each casting about its longitudinal central plane, and the end joints differ only the depth from the the base, single template sufficed locate ill the holes drilled. the case the shallow oints was simply ase omitting the holes overlapping the base that point. Through these holes the groups three astings were bolted se- urely together for the peration planing the ase, For the ticklish job milling the cable grooves their accurate 2-in. radius cross-section and the radius center cable, novel set-up was employed. The four bolted sections the saddle were held sta- tionary, while the tool was run over the surface guiding arrangement de- vised the plant and appropriate for this pur- pose, General appearance Machining equipment consisted cutter head ounted horizontal miller, which trav eled the ways curve base. Traverse the and right, with its cutter head and tool, was means rack and pinion, the rack being attached the cast iron base sections. This rack was definite radiu from the center the circle which the cable were based. ntly, the was car (Concluded on page 1281) iA yo _ aa - ~ the work and the tool used machining the cable grooves The Iron Age, November 12, 1931—1233 sf a a = ‘ | ne — : 4 2 7 INCLUSIONS VALVE FRANK STONES Fig. Swedish wire. Metallurgist, Eaton Spring Corpn., Detroit (Reduced about per cent from 100 diameters. Section and Steel Institute re- stress than the endurance limit, may start fatig port the “Heterogeneity Steel Ingots” failure, even though the nominal computed stré stated that ingot ever produced com- below the endurance limit the material. pletely homogeneous, however carefully the will, however, shown that the case steel may have been made and equally many spring failures the inclusion not alone true that ingot ever produced free from segre- its detrimental effects the wire. often in- gates and non-metallic inclusions, their number and closed envelope soft iron, and this may, and manner distribution varvil with the steel-mak- often does, extend the surface the wire, th: ing process, melting and pouring practice, and size most highly stressed part the spring. ingot made. The importance impurities and inclusions Five Principal Impurities Commercial Steel has long been recognized. Griffith, (a) the Available knowledge regarding the British physicist, believes that the great difference and identification between the theoretical cohesion and the actual inclusions far from complete. There seem values obtained tensile tests may best least five principal impurities commercia plained the hypothesis that throughout the mass sulphides iron and manganese, silicates all solids are minute discontinuities flaws, and iron and manganese and oxide iron. And the that the effective strength engineering materials not usually occur the pure state. might increased, perhaps times, such There little divergence opinion from flaws could eliminated. statement that inclusions are principally the prod Regarding failures correctly heat-treated uct the reaction the oxygen and impurities springs which have not been over-stressed, safe the unfinished steel and the deoxidizers such say that per cent those investigated the manganese and silicon, besides which there writer were due the presence non-metallic in- clusions located near some highly stressed area. possible for inclusion have little effect the life spring. Gillet and Mack point out (b) that inclusion which some dis- tance away from the point maximum stress need not necessarily cause failure. They obtained from Prof. Moore specimen normalized steel which had endurance limit 42,000 per sq. in., and which was run 40,000 lbs. per sq. in. for 100,000,000 cycles without failure. This was found have large longitudinal with its tip 0.1 in. away from the point maximum stress. They conclude that, when the position inclusion such produce higher local (a) Rupture and Flow Transacti ms, Royal S« ciety Metals” Moore and Kommers (Reduced about per cent from 750 diameters.) Iron Age, November 12, 1931 —— ™ FAILURES about one-fourth from 150 diameters INETY per cent the failures correctly heat-treated springs investigated the author have been due the presence non- metallic inclusions located near some highly stressed area. adds that about per cent the hardened and tempered vaive spring wire now use badly laminated. The danger surface decarburization the life spring empha- sized. plea made for greater proportion tested material reduce the risk breakage. German machine tests valve springs one time. that small pieces furnace linings, landers, The consideration impurities valve spring linings, washings from the nozzle, oxidation wire would most incomplete without some men air during teaming, and dirt ingot molds are tion that type which appears laminations, sources inclusions which, owing their ghost lines banded structure. afe say buoyancy, have insufficient time rise the that per cent hardened and tempered valve urface the metal and are entrapped the freez- spring wire use the present time crystals the ingot, collect the slower laminated. ooling portions, giving rise “ghosts.” There evidence that non-metallics are soluble solid teel. The association purely mechanical one. Photomicrographs, Figs. and are average revealing laminations for the particular type 11 Iron and Steel Institute, 1918, Vol. I, page 287. etching reagent employed. There is no doubt that (d) Brearly, A W. and H t ind Ingot M ‘ ghost lines are associated with inclusions, and many cases inclusions can seen lying the cen- ter the streaks which appear lower carbon content. For many years leading metallurgists have tempted systematic investigations this type defect, and the result may gaged considera- tion the microphotos, which represent the best material available. have, however, result these researches, several interesting theories Stead (c) states that the evidence his experi- ments conclusive that non-metallic inclusions steel not lead ferrite crystallize around them, and that phosphorus—almost always associated with inclusions—which leads the formation ferrite ghost lines; further, that when the inclu- ions are not associated with high phosphorus, ferrite lines appear. Fig. surrounded ferrite found broken valve spring. (Reduced about one-fourth from 1000 diameters.) Brearly (d) his book “Ingots and Ingot Molds” The Iron Age, November 12, 1931—1235 Fig. surrounded ferrite found broken valve spring. (Reduced about per cent from 600 diameters says: “There can doubt slag exerts selec tive action and forms nuclei around which micro constituents appearing the solid steel tend segregate.” support this experimented drilling small holes billet, placing quantity hammer scale, open-hearth slag and pure silica sand respectively the holes, riveting over, fusing the heads, and finally heating and rolling the billet into bar. When the part containing the hammer scale was sectioned, nothing was found save large patch ferrite, due obviously the decarburizing action the scale. The ferrite border about the open-hearth slag was very distinct, which also may have been due partly decarburization, but the ferrite border around the silica sand was unques- tionable. How (e) does not agree that slag will attract fer- rite, but expresses the view that the austenite grains dispose along their surfaces any slag which they may contain and, later cooling through that range, deposit the ferrite (or cementite) like manner, and hence this later arranged matter found surrounding the earlier arranged slag. Howe (e) Metallography Steel and Cast (f) Ghost Lines and the Banded led and Forged Mild Steel Jo al lr nd $ I tute, 1926, Vol. I, page 213. abe f- eat B > ¢ ‘ aid a » a } > A Fig. fin rolled into valve spring rod and drawn into wire. The spring failed. (Reduced about one-fourth from 150 diameters. 1236—The Iron Age, November 12, 1931 has much evidence prove this motive power the austenite grain. Swedish Wire Low Phosphorus Concerning Swedish spring wire with its low phosphorus content, extremely doubtful that Whitely showed that only when variations percentage phosphorus exceed 0.07 per cent does cause the removal the carbon, and also showed that even with phosphorus down 0.004 per cent banded structure was evidence. The theory that slag non-metallic inclusions attract ferrite also open doubt, when con sidered that lengthy heating high temperatures, even followed slow cooling, will remove banded structure some steels, the inclusions remaining their original positions. That ghost lines can removed lengthy heat- ing advantage, since the accompanying evils not allow its use commercial remedy. From all available data would seem certain that lines are the result heterogeneity not only phosphorus, but also sulphur, though far a 4 4 4 ~e Fig. domestic wire. (Reduced about one- fourth from 150 diameters.) from certain whether inclusions are incidental their direct cause. the case spring wire certain consolation may gathered from the fact that invariably laminations gradually diminish toward the more highly stressed portions the wire; and de- that they are the direct cause spring failure, especially since practically all high-carbon steel valve springs are coiled from laminated wire. They probably exert considerable influence the path the track travels once starts, in- dicated Fig. Inelusions which will cause fail- ure are such are shown Figs. and This type inclusion surrounded border fer- rite very well marked, and many cases close enough the surface the wire open into crack, breaking very short time after being put into use. This type reacts distinctly the stannous chloride test the inclusion identification chart Campbell and Comstock, which indicative iron oxide. That inclusions can mechanically rolled into wire shown Fig. The inclu- $10 | sion this case appears decarburized fin which has been rolled into the rod, the decarburized area being bordered scale. Surface Decarburization and Life Springs The importance surface decarburization the life spring cannot overestimated. The effect this lower the endurance limit the skin the wire where most highly stressed about half what should be; other words, the spring has the torsional fatigue properties untem- pered wire. Such wire shown Fig. When considered that there little lee- way between what valve springs are required and what the best wire obtainable will do, the probability defects causing breakage very great. The stereotyped tests which bundle wire subjected are helpful eliminating some defective material, but cannot ignored that, while one both ends bundle may good wire, some other portion may defective. Necessity for greater portion tested material avoided. This new thought. There already German machine designed test valve springs one time. The springs are given the service pre- load and per cent more stress than service and within this range vibrated 5,000,000 cycles 1500 camshaft r.p.m. the springs are going fail they will during this test, and such tested springs may used with considerable confidence, and with little risk the inexplicable spring fail- ure often dismissed with vague allusion fatigue. USE AND ABUSE HACKSAW BLADES AND BAND SAWS THOMPSON AWS assigned one operator are seldom abused. Considerable mistreatment may occur, however, they are available for general shop use, espe- cially the case the relatively more expensive band saw. One the most common forms abuse, perhaps, failure select the proper type blade for the ma- terial cut. Steel cast iron, for instance, re- quires highly tempered saw—too brittle for the high speed required saw for cutting wood. the other hand, the flexible wood saw too soft cut steel cast iron. The form the work, well the material cut, should govern the choice saw. Metal tubing thin sheets are example; difficult cut them with saw having coarse teeth, but easy enough fine-toothed blade used. radius cut, care should taken select saw narrow enough make the turn without cramping. adjusting the saw blades the machine, important get the correct tension. Too much too little tension may cause the blade perform poorly break. The guide rollers the machine should adjusted close the work give the blade proper support, but should not come contact with the saw teeth, this will dull the saw and change the set the teeth. When steel sawed should held rigidly vise clamp. the piece cut off heavy bulky should supported cannot fall when cut, this will injure the saw blade. Too Much Feed Breaks Saw Blade Excessive feed the most usual cause saw blade breakage. Where adjustable feed used the adjustment should permit the blade clear itself, otherwise the friction will cause the blade heat, stick the slot and break. Saws having gravity feed should not forced adding weights other means. When work fed into the saw hand very little pressure should used and the saw should allowed clear itself cuts. lubricant coolant should used when sawing material requiring lubricant coolant other ma- chine operations, such drilling milling. This will and keep the work cool. aand saws be wel lubricated when carry away the important that cutting steel and similiar material. Materials which ordinarily are machined dry should sawed dry. Relieve Tension Idle Band Saws good practice relieve the tension band saws when they are idle for some time—over night over the week end. This avoids stretching the saw unduly, and will lengthen its life. The “roll- ing” band saw for storage should done only expert who thoroughly understands the operation. dull, gummed, broken blade should never used; such blades not only slow production but may cause accident. Hack saw blades that have been broken one end may salvaged softening the end for short distance and drilling hole match the hole the unbroken end. few teeth are broken out, grind the edge the blade the damaged place surface obtained that will not catch the work. The grinding should eased off each side the broken teeth. get the full use hack saw blade, place the vise; this tends shift the work the vise and, bringing more teeth into action one time, increases the cutting efficiency. The Age, November 12, 1931—1237 é { rapid advance involving types mac COMMERCIAL HEAT-TREATING PLANT HAS FURNACES nok cha i he ic factors chasers in at nging treatin produc metal } parts in 1e are HARRY TURNER Secretary, Ohio Heat Treating Dayton, Ohio metal tech- but also the characteristics of the treated. steel, the vital Heat Treater Must Have Broad Knowledge exacting should possess general knowl- their requirements and send edge the more technical side the metallurgists and inspectors such the value the rate producing plants see that their holding time, critical temper- specifications are followed. atures, quenching and drawing opera- This development has particularly tions, and should able judge the affected shops, necessitating heat modern furnaces and auxiliary equip from the ulti- product. likewise effect the tool de- results mate use the should know the furnace control, proper testing throughout the product, location and, above all, type operator recesses, tolerances and the supervisor who understands not only t} ne bare handling ol effect improper finishing grind- materials, ing and handling the piece. 1238—The Iron Age, November 12, 1931 "Re 4 a The commercial shop more sub- ject complaints and rejections than heat-treating department large plant, where responsibility can im- partially and easily traced. Hence often compelled trace tactfully the history product which has only one operation through sev- outside plants. This itself service surprising knowledge and good judgment. Many small found their heat-treating departments inadequate and therefore unsatisfac- tory, with the cost rehabilitation and operation not commensurate with the amount work handled. dis- tricts where local reliable commercial heat-treating shops have been estab- -~ t} ished they have been led abandon these departments, their work passing the commercial shops already set with the necessary equipment, ca- acity and technique handle cost and speed practically jual department the plant Cognizant this trend, our com- any recently constructed new plant signed especially for heat-treating perations. Eight oven-type furnaces ire arranged two rows, back ack, with monitor roof overhead for calizing and removing excess heat, thus adding the comfort the and the ease and convenience operation. Sixteen Furnaces Available The furnaces range from (inside furnaces. addition, there are seven pot-type furnaces, including salt, lead, cyanide and aerocase baths. For drawing and tempering there gas-fired, shelf-type, recirculating air- drawing oven, which has proved satis- factory. Recording and controlling instruments are mounted two pan- els, one for each row furnaces, that they are easily accessible the operators. Furnaces are equipped with single-valve, automatic proportioning mixers combined with mixture pressure gages and electric control valves, with signal light sys- tems for observation and control. The building 43% 120 ft. and has abundant window giving natural light, spite the fact that the light handicap furnace operators who are tempted sup- plement the records instruments their own color observations. How- ever, liberal use record ing controls removes this responsibil- ity from them. space Quick Aging Zine Die Castings Among the almost infinite number specifications heat treatments for the many classes work encoun- tered commercial shop, the quick aging zine die castings recent EAT-TREATING furnaces are ar- ranged two rows, back back, with monitor roof overhead for localiz ing and removing excess heat. castings change their characteristics aging nor mal atmospheric temperatures for long periods. They may expand after machining much 0.030 in. castings about in. long. Other prop These die addition. erties may change irregularly. After 24-hr. treatment 300 deg. F., this expansion eliminated. One the hardening furnaces de- signed for 1800-deg. operation has been set aside for this work and ranged with automatic gas and tem- perature control produce the practically straight-line temperature 300 deg. nor recorder the large carburizing fur naces. All piping concealed the covered trench between the rows furnaces. — 4 The Iron Age, November 12, 1931—1239 mally rather difficult procure uni- form heat such tempera- tures furnace with rated fuel capacity for 1800-deg. operation. This readily accomplished, how- ever, means specially designed burner with automatic control which heats the entire hearth and material uniformly. This furnace used be- cause the automatically controlled vertical oven could not spared for this purpose. All piping concealed covered trench running between the rows furnaces and large enough permit freedom work any the pipe. Branch lines, furnaces, uch air and gas lines electric conduit for con- trols, pyrometers and signal lights and water and drain lines quench- ing tanks, are buried the equip- ment proper. This arrangement in- sures freedom from the maze pip- ing usually found departments, giving exceptionally clear shop overhead and around the furnaces and other equipment The air designed loop using two blowers, one each system with valves arranged that each blower supplies air one both enabling either both blowers used for the entire shop production requirements demand. side sides, One Large Furnace Over-Fired The large Mahr furnace fired with system circulating waste gases under the hearth, giving difference temperature between the furnace heating chamber and the vent outlet gases over 500 deg. The case thickness uniform throughout all pots, even when pots without legs are used. The hardening furnaces are all the under-fired semi-muffle type. 24-hr. service maintained from the time materials heat treated are called for until they are returned the customer. When work re- ceived, shop filled out and the The speci- cards routed. record work are fications accompanying the work checked against the material com; sition well against perience records guard error. the specification appears fault, the customer consulted mendations made. the practice give vice, based upon mended types steel, design tures, heat treatment, tolerances, and subsequent finishing—all based the ultimate use the tool. Fai ures and rejections are minimum and friendly with customers maintained. When work finished, the results checked various testing insure conformity with the specif cations. Contact with the job main- tained regular intervals after livery check upon the satisfac tory performance the heat-treated material. reco? establish advisory its experience company’s S¢ Magnesium Alloy Finds Varied Uses Germany which coming into wider use Germany, especially for aircraft, was first introduced commercially Ger- 1909, when samples were shown the International Aeroplane Exposition Frankfort. many about were made during the war, and since the armi tice has been widely adopted German aircraft builders for use ings, fuselage and for rior furnishing large transport plar Recently the han a na ALi 1Y I ‘ other furnishings larger planes. The annual German production the alloy about 6000 tons, made ubsidiary the German Dyestuff Corpn. The only other Continental maker operates Italy under license. manufactured Germany and taly, elektron has specific weight 1.8, melting point 625 650 deg. C., and electric conductivity 18. The tensile strength ranges from elektron the and kg. per sq. mm. (35,000 60,000 lb. per in.) for rolled mate- rial. The Brinell hardness ranges from 70. While elektron oxidizes slowly, the white coating formed the surface does not impair the metal. When used aircraft construction, brass paint usually applied for protective coating. The alloy inflammable more than 625 650 deg. C., and when being machined, turnings occa- sionally become ignited unless sharp kg. per sq. mm. (14,000 are used medium and low 31,000 per sq. in.) for castings, speeds. cable car, used for transportation over mountain passes Germany, has body formed entirely magnesium alloy. (Left) IRCRAFT builders are making increased use magnesium alloy for motor parts, fuselage, wings, interior furnishings and gasoline tanks. This tank wholly magnesium alloy, including the baffle sections inside. (Below) GERMAN fireman holds aloft ladder fabricated rolled magnesium alloy, supporting the weight his (Right) 1240—The Iron Age, November 12, 1931 a = | = THE MATERIAL FACTOR CARBON ARC WELDING the kind steel best suited carbon are welding were voiced the fall meeting the American Iron and Steel Institute and the meeting the American Welding Society during the National Metal Congress September. Issue was taken with the presentation the views the Lincoln Electric Co. both meetings. There here presented both sides this controversy paper Wilmer Stine, the Lincoln company, read the institute’ abstract the ing Oct. 23, and abstracts the discussions which were presented there and the National Metal Congress. Abstract Mr. Stine’s Paper are welding, the metal the plates parts being welded enters into the composition the metal forming the seam, complete study the elements which affect the results are welding should include study used the manufacture plates and shapes well the electrode material, Electric are welding will con- sidered herein that method fusion welding which the seam welded filled with molten metal melted the heat electric and allowed solidify, thus forming the weld. Electric arc welding may divided into three classes, fol- lows: (a) Metallic arc welding with bare or washed electrodes (b) Metallic welding with shielded arc electrodes (electrodes with a h ; coating to protect the arc from the oxy- gen and nitrogen the atmosphere) (c) Carbon are welding with a shielded are, Carbon are welding with shielded arc seems offer the best method welding for study the factors that affect the welding characteristics steel. Defects that may develop because certain characteristics the steel forming the weld are follows: (a) cracks, (b) slag holes, (c) gas holes. Causes the first class defect seem fairly well understood. This investigation largely confined the causes the latter two classes defects. Gas holes are not formed any appreciable extent where the are oxidizing atmosphere. The weld metal such cases over-oxi- dized and has very little ductility and will not high-quality weld. quality are welds can only made with shielded arc. Gas holes become important factor such Samples Steels Used The cooperation several steel manufacturers was obtained fur- nishing different series samples for welding tests. The first series samples was made taking very low-carbon, low-man- ganese steel and melting tric furnace, adding various amounts carbon and manganese. This steel was then rolled into plates and welded. All samples this group proved poor welding quality. Subsequent tests and analysis indicated that the used basis for this series samples had been deoxidized with excess amount aluminum and that the aluminum was the principal controlling factor. The determina- tion small quantities aluminum steel difficult and the accura problematical and therefore not considered reliable. Analysis the basic steel the above series showed 0.018 per cent aluminum. second series samples was ob- tained from various steel mills, and consisted fire box, flange and tank steel having carbon range from 0.12 0.20 per cent. steel maker was asked furnish informa- whether the steel was recarbonized, how was deoxidized, and whether was killed rimmed. third series samples various carbon content was obtained from one steel maker and consisted steel varying specifications from SAE 1010 SAE 1050 inclusive. fourth group samples was ob- tained from two steel makers and consisted samples several heats representative commercial The results few tests are shown the table. While the results only seven tests are tabulated, several hundred such tests were made. was found that steel which formed slag holes the weld, shown Fig. invariably had been aluminum killed and contained preciable amount The sam- ple shown contains 0.03 per cent characteristic checked covering piece good welding steel with thin layer before welding it. The result was very similar that shown steel. was characteristic matter melting temperature the inclusions, sim- ilar test was made with which has about the same melting temperature (2050 deg. C.) The result was almost identical. evident that these slag holes depressions are caused inclusions the steel which remained finely divided solid inclu- ions during the steel making process, but during the are welding process melted and coalesced globules which solidified ahead the steel and formed holes pits weld metal. These holes can elim- inated using slag-forming flux low melting temperature which will combine with the slag the steel, forming new slag having its melt- ing temperature below that the form lar been fairly well established capacity steel for holding gases solution varies directly with temperature and the content alu- minum, silicon and manganese and in- versely with the carbon content. the capacity the steel for hold- ned value equal what was the ingot molds, the icon manganese mu