The Iron Age 1941-08-07: Vol 148 Iss 6

AUGUST 1941 DEFENSE CALES for Defense? Yes, Fairbanks Printomatic Scales defend many plants against honest errors made reading scales, jotting down weights and later interpret- ing these hurried scribblings. prevent the losses such errors cause, use Fairbanks which can include related data well weights... records which are always accurate. These scales are avail- able with printing and recording devices fit practically any plant requirement. For details applications your weigh- ing problems, write Fairbanks, Morse Co., Dept. H38, 600 Michigan Ave., Chicago, Ill. Branches and service stations through- out the United States and Canada. FAIRBANKS, MORSE CO. 600 Michigan Avenue Chicago, . y % \RB TAPERED TREAD barking dog never noisy crane will always pinch your purse—for every screech, thump, and growl DRIVE WHEELS means wear. And you can’t have wear without expense. Reduce Noise and Wear Whiting cranes have been designed for smooth, quiet, WHITING CRANES high-speed performance—for long life and minimum wear. The load the bridge Among the many features which assure efficient, trouble- drive reduced and the free operation are precision-cut herringbone gears, tapered- wheels and rails last tread drive wheels, rotating-axle bearings, flexible cou- longer because drive plings, and heavy duty, anti-friction roller bearings. The entire unit built start quickly, operate smoothly, and The crane kept spot loads accurately. Listen Whiting crane. will squarely the runway the quietest crane you ever heard —and the longest without binding. wearing, too. Capacities from one 400 tons. Also electric hoists from tons. Whiting Corporation, 15601 Lathrop Ave., Harvey, Ill. Builders quality cranes for over years. SEND FOR BOOKLET “How Write Traveling Crane 4 | E A AUGUST 1941 VOL. 148, NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager Managing Editor News Editor Technical Editor Machine Tool Associate Associate Editor Editor Editor COSMAN Associate Editor Associate Editor WINTERS Art Editor Washington Editors MOFFETT JAMES ELLIS Resident District Editors CAMPBELL HERMAN KLEIN Pittsburgh Chicago Cleveland Detroit Editorial Correspondents Buffalo Cincinnati FRAZAR CHARLES POST Boston San Francisco HUGH SHARP JOHN McCUNE Milwaukee Birmingham SANDERSON ROY EDMONDS Toronto, Ontario St. Louis LEROY ALLISON Newark, Editorial The Man the Moon Technical Articles Basic Open Controlled Brazing Copper Die-Typing Speed Production..................... Torque Tube Flanges from Choice D.C. Arc Welding New Machine Tools Features This Week Washington the West Fatigue Cracks News and Market Reports 106 Summary the 109 The Industrial Pace 110 District Market Products Advertised Copyright, 1941, by Chilten Company (Inc.) DIX, Manager Reader Service Advertising Staff Herman, Chilton Bldg., Philadelphia Hottenstein, 101? Otis Bldg., Chicago Leonard, 100 East 42nd St., New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd St., New York 428 Park Pittsburgh Don Harner, 1595 Pacific Avenue, Long Beach, Cal. O O O Member, Audit Bureau of Circulations Member, Associated Business Papers Indexed the Industrial Arts Index. Pub lished every Thursday. Subscription Price United States and Possessions, Mexico, Cuba, $6.00: Canada, $8.50; Foreign, $12.00 year. Single copy, cents. Cable Address ‘'lronage, N. Y." Machine Tool Activity Non-Ferrous Market Scrap Market Construction Iron and Steel Prices Warehouse Prices Sales Possibilities Owned and Published CHILTON COMPANY (Incorporated) Executive Editorial and Office Advertising Offices Chestnut and Sts. 100 East 42nd St. Philadelphia, Pa. New York, N. Y. U.S.A. U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, GEORGE GRIFFITHS, EVERIT TERHUNE, VAN DEVENTER, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY CHARLES HEALE Vice-President Vice-President Vice-President 116 120 122 128 . WESTINGHOUSE COMBINATION LINESTARTER For Motor and Circuit Protection CLASS 11-206 Magnetic motor circuit switch—motor overload protection—nofuze circuit protec- tion—all one unit. Bi-metal gives permanently accurate over- load protection. quench- ers protect contacts—save main- tenance. Four-in-one Unit saves installation time—saves space— saves wiring—provides greater protection for operators. WESTINGHOUSE SAFETY SWITCH For Circuit Protection Diamond-pointed break jaw and extended-blade construc- tion prevent burning and beading contacts. One- piece copper construction saves money preventing power loss. Quick make, quick-break Types and Ample space for wiring. Solderless lugs. arc quenchers 575-V switches. saarnet Wactinghn Call your nea SOs WESTINGHOUSE MOTOR WATCHMAN Manual Across-the-line Starter for Motors hp. CLASS 10-100 Quick make, quick break toggle action prevents contacts. dicating. Bi-metal disc over- protection for contacts. Ample wiring space. Rust-resisting parts. Silver contacts. Key- hole mounting for quick, easy installation. WESTINGHOUSE AB-I BREAKER For Protection Eliminates switch and fuses. Bi-metal overload protection. protection for con- tacts. Saves maintenance time and production time— circuit outages can re- stored operator. live parts exposed. Door opens only when switch “Off” position. Occupies approxi- mately 40% less space than switch and fuses. | F Tl M 4 i ale $ ffi i i ice Distribut The Man the Moon current wave price rises, outside the metal working industry, and the vociferous conversations from Washington with respect controlling them remind story. Once upon time there was precocious lad who was good fig- ures. addition this had self confidence quota that, usual with precocious lads, was considerakly above par. This youngster became interested tides, during vacation spent his family ocean beach. noted that approximately twice day considerable portion the beach was covered with salt water, due tidal effect. Looking the statistics the American coast line and figuring that the average encroachment the rising tide was about 100 ft. beach, the youngster figured that tidal effects were depriving the American con- tinent some several hundred million square miles territory that was under water about half the time. ran papa with his findings and said him: wish that you would give permission control the tides, for will then add.a lot usable territory this And pop, being busy man whose mind was occupied with many other things, said: son, you have sonny went down the beach and when the tide began come in, addressed the rising waters vigorously. you dare,” said he, “to come inch farther will tell papa you!” But the ocean waves paid attention him whatever and continued encroach upon the beach. Our young friend was reduced tears the apparent failure his scheme make America bigger and better continent. stranger, walk- ing along the beach, noticed his grief and enquired the cause it. “Boo, hoo,” the boy replied, have told the naughty tide stop coming in, but does not pay any attention me.” “Well, son,” said the man, “if you are aiming control the tide, you must first control the moon, because the moon controls the tides.” sonny ran papa again. Said he: want you make the moon behave, because make the tide stop coming And pop, paying attention this time, said: “Sorry, boy, but afraid the moon little too high for reach Now apply the analogy. Just the moon the principal cause fluctuations tides, are labor wages the principal causes price movements. And useless try regulate prices without regulat- ing wages was for little Johnny try command the ocean tides without first getting control the moon. Maybe the man the moon responsible. Nobody ever was able say definitely who was. Maybe John Lewis William Green somebody like that. any nobody this earth seems able reach and regulate him. | : | AUGUST 1941 | ‘ = — = : 4 j % 45 Seam-welding the nose the body practice bomb. FLOOR PLATE STRUCTURALS PILING RAILS TRACK ACCESSORIES REINFORCING BARS Moving 100-lb. sand practice bombs “Flying Fortresses” scheduled for bombing drill. Another INLAND STEEL Defense Job Thousands practice bombs are being used the United States Army and Navy develop the marks- manship America’s crack young aviators. Shown the left are practice bombs being fabri- cated manufacturer from and ga. Inland Hot Rolled Pickled Sheets. All seams are resistance welded. The capacity these bombs 2.08 cu. ft. The Navy loads them with water—the Army prefers sand. Like many other Government jobs, the order for these sheets has the right-of-way the Inland schedules, for our entire organization geared our No. job—National Defense. | ticles, THE IRON AGE, Feb. and 13; May and 29, 1941, account was given the great variety refractories used the open hearth furnace above the sill plate level. The data herein deal mainly with the refractories used the hearth and the checkers, but reference will also made those employed the con- struction the gas and air up- takes, slag pockets and valves. general all these parts (with the ex- ception the hearth) are con- structed silica fireclay brick, but the particular quality used de- pends upon the severity the working conditions. Thus, for the bottom the checkers medium alumina fireclay brick quate, but the top the check- ers where the higher, silica brick high alumina fireclay brick are employed. The Hearth The terms used describe the different sections the hearth vary considerably from one plant another. Thus the sloping part the hearth the back and front the furnace are described some plants the “breasts” and this meant not only the dolo- mite magnesite covering, but also the backing brick. the pres- ent account, the brickwork these the previous series ar- *Diagram illustrating nomenclature IRON AGE, May 22, 1941, 41. Central CHESTERS Research Department, United Steel Companies, Ltd., Sheffield, England ° ° ° ° ° Continuing the discussion basic open hearth refrac- tories (THE IRON AGE, Feb. and 13; May and 29, 1941), the present series three articles, which this the first, deals mainly with refractories used the hearth, checkers, and below the sill plate level. These data are particularly timely, what with the growing inter- est here basic construction for improved open hearth efficiency. parts will described “banks” and that either end the banks,” the term “breasts” being used exclusively for the fettling rammed mate- rial covering these banks. (A) CONSTRUCTION: According Buell, hearths 85-in. thickness are employed America, one such hearth consist- magnesite brick and in. ground magnesite. Great Brit- ain, the other hand, the brick- work furnace bottom rarely exceeds in. thickness and often only in. in. The exam- ples are extreme but serve show the wide variations from one plant another. Some degree insulation the bottom plate generally achieved the use fireclay brick next the pan and occasionally furnaces are built with layer insulating brick, for example, porous silica brick low temperature insulation the magnesia-asbestos type, be- low the firebrick. Such practice will clearly reduce heat losses and result more ready sintering the monolithic section the hearth, but may lead trouble due the lower temperature gradient the hearth, and consequent greater penetration slag and metal. British open hearth fur- naces the 80-ton class are gener- ally constructed with in. in. bricks (three four courses set the flat) with courses beneath. The monolithic hearth above usually has mini- mum thickness about in. The use such thin hearths the re- sult trying get bigger steel production per furnace and asso- ciated with the present practice renewing hearths every two three years, being considered more economical tear out old hearth and incidentally obtain high recovery the bottom bricks than continue using hearth requiring relatively large amount THE IRON AGE, August 1941—37 fi | | ; 3 © fettling per ton steel pro- duced. Usually the hearth bricks are arranged (see Fig. mini- mize the risk break-out joints. The older practice was build horizontal layer bricks the pan together with right-an- gle steps the sides and obtain the hearth shape employing varying thickness monolithic material above. More recently the practice adopted that varying the brick thickness give ap- proximate inside hearth contour and using monolithic hearth roughly equal thickness through- out. The older practice using flat sub-hearth had the advantage that the necessary expansion al- lowances could made along line under the side and end walls. With the shaped brick hearth, where the expansion joints are left open, there more risk their becoming filled, leading subse- quent buckling the hearth. The methods employed con- structing monolithic hearths, in- cluding the preparation the dolo- mite magnesite used for this purpose, could scarcely dealt with all adequately less than small book, particularly the improvements and experience the last few years were in- cluded. rule, British open hearth furnaces are lined ram- ming tarred “basic” (dolomite cal- depth about in., burning this position the highest tempera- ture available, and building the remaining thickness throwing layers approximately in. thick and burning these position. The alternative methods, namely, ram- ming burning-on the whole the “basic,” are, however, also em- ployed. Since the ordinary coarse ground dolomite difficult sin- ter, per cent finely ground basic slag normally added the lower layers and then decreasing percentage the working face approached. The addition this slag compro- mise and the material prop- erly graded, that is, contains suf- ficient proportion fine material, the use slag can dispensed with. After burning-in, the hearth slagged, some four eight tons being required for 80-ton fur- nace. The results obtained vary greatly according the precise technique employed. the 38—THE IRON AGE, August 194! hearth should properly dried out before the first tarred dolomite layer rammed position and only dehydrated tar suitable vis- cosity should used. The amount tar required give optimum ramming will usually found between and per cent the weight the dolomite. The dolo- mite should preferably mixed hot with the tar and not em- ployed immediately should pre- heated least 122 deg. prior ramming. Hand rammers ap- normally employed and these are neighboring furnace door avoid sticking. Given proper control, far better compacting can obtained the use pneumatic rammers. Thus 3-in. layer after hand ram- ming can often reduced another in. the use pneu- matic rammers. The use me- chanical rammers has often been objected the grounds pos- sible lamination and consequent lifting the hearth lack steel tightness, but the top sur- face layer roughened, for example, means pneumatic chisel, before another rammed position, trouble due lamination fact experi- enced. With tilting furnaces similar bottom making technique em- ployed but the thickness the rammed portion often consider- ably reduced and that the burned-in portion increased. Since the bottom cannot examined after each cast, being covered with metal for months time, ° ° IG. gering basic brick the sub- hearth. essential that the original bottom The technique employed stalling magnesite hearths simi- lar but should borne mind that the latter are even more refrac- tory and that adequate sintering occur the material must either finely ground (see Table II) some bond (for example) basic slag mill-scale added. For this reason usual burn-in mag- nesite hearths rather than ram layers with tar bond. The amount slag required give adequate sintering the lower parts close the brickwork may much per cent, while certain plants the bricks are subjected slag wash prior burning-on the first layer magnesite. (B) MATERIALS: Brick. already stated, the in- sulation used The United Steel Companies’ works has been the porous silica magnesia-asbestos type. obvious, however, that almost any low high tempera- ture insulating brick could em- ployed, provided the remaining thicknesses brickwork and hearth were such insure the insulation not being raised above its maximum Since with thin hearths the risk break-through many operators prefer omit in- sulating brick completely. The fireclay brick used cover the pan the insulating brick layer are generally the medium alumina type and good quality, described THE IRON AGE, May 29, 1941, connection with fur- nace doors. ~ A = 4 f / % 7 - | | N | The properties number typical magnesite brick used open hearth fur- nace bottoms are summarized Table rule, very dense magnesite brick the type origi- nally made Austria ferred, the porosity frequently be- ing less than per cent. The ther- mal shock resistance such bricks frequently rather low but this consequence since they are not heated rapidly and any ease cannot fall out position even cracked. During the last few years brick made from stabi- per cent silica content have been found give excellent results open hearth furnace bottoms and have largely replaced magnesite brick fixed furnaces. Here again the porosity frequently below per cent. The modern dolomite brick gives trouble due hy- dration, showing signs col- lapse even after boiling water for several weeks. very strong both cold and temperature, com- with the best magnesite brick. Its thermal shock resistance tends low but, provided covered particular consequence. Its slag re- sistance may not quite high that magnesite, but both lab- oratory and works tests suggest that adequate for use this position. the United States there has been marked tendency replace the magnesite with chrome chrome magnesite brick, and cover these with small layer chrome plastic. This practice has the advantage that the risk hy- dration furnace bottom during shut down minimized. More recently the working hearths have been made chrome magnesite soldier courses 9-in. depth covered with magnesite layer only about in. in. thickness. eral the hearth proper British called “dead-burned” dolomite “basic.” Since dolomite, even when electrically fused, still contains free lime and hydrates very read- ily, the term “dead-burned” misnomer. is, however, true that the hydration rate “basic” greatly reduced high tempera- ture calcination cupolas. The general practice take rela- tively pure dolomite stone and this pressure blown cupola using alternate layers stone and coke. The temperatures obtained are very high (probably the order 3092 deg. F.) while the ash from the coke facilitates the sintering increasing the flux content the stone. The porosity the product varies from about per cent, averaging about per cent. The bulk density va- ries from 1.8 3.2, averaging about 2.8 gm. per ml., while the specific gravity, which varies very little with the firing treatment, generally about 3.35. The relation between the bulk density and the firing treatment marked, and hence the bulk density can used index the firing received and the probable stability the material, though some allowance necessary for the analysis the product. Ordinary lump dolomite can stored for several weeks be- fore use, but crushed deterio- rates much more rapidly. The proc- ess deterioration, often referred hydration the lime the mixed oxides. should not confused, frequently is, with dust pro- duced grinding. Whether fact perished can readily ascer- tained carrying out loss ig- nition test which should not the ordinary way exceed about per cent. would expected, the hy- dration most marked with the fine section and hence the gray lumps the material are found turning white and becoming soft, may taken for granted that the consignment whole has hydrated. Normally, lump dolomite crushed either jaw crusher forated edge mill, the relatively coarse product being used both for bottoming and for fettling. The use such coarse and even-size material for the production lin- ings (see Table II) has long been known result high porosity cently that trouble has been taken produce dense hearths proper grading the material. The rela- TABLE Basic Open Hearth Furnace Bottom Bricks Magnesite Code No.: Brick Apparent porosity, per cent 24.2 Bulk density, gm. per 2.67 Lb. per cu. 167 Apparent specific gravity 3.52 Cold crushing strength end, Permeability air, perp. in. face, 0.08 After contraction, 2732 deg. Refractoriness under load—maintained temp. test, per sq. in. Failed Rising temperature test, per sq. in.: Initial softening Rapid softening Failure Thermal shock resistance, No. re- versals 30+ Magnesite Dolomite Dolomite 18.7 22.1 24.7 2.89 2.58 2.53 158 3.56 3.31 3.36 >8300 5090 0.12 0.088 0.12 Failed Failed min. min. 2642 2804deg.F. 2660 deg. 2768 deg. 2930deg.F. 2750 deg. 2804 3056deg.F. 2912 deg. TABLE and Chemical Analysis Typical Fettling Materials for Basic Open Hearth Furnace Bottoms Grading BSI Nearest Equivalent Sieves —Tyler Sieves 25- mesh 28- mesh 72-150 mesh 65-150 mesh Through 150 mesh Through mesh Chemical Analysis MgO Al,O; + FeO; Loss ignition Magnesite, Magnesite, Dolomite Coarse Fine (Basic), Coarse (Per Cent) (Per Cent) (Per 36.9 13.5 8.5 28.4 22.5 18.4 25.0 17.0 7.3 5.0 13.0 2.3 1.5 39.0 6.7 82.8 3.2 8.4 for 25.4 coarse 0.2 THE IRON AGE, August Ly | Fig. 2—Fettling basic open hearth furnace banks. tion between grading and packing density will discussed more detail the later section dealing with induction furnaces, where will shown that the fine fraction not only helps give high pack- ing density but also virtually con- trols the sintering the material. With magnesite hearths, also, the use relatively coarse batches has been normal though much im- proved results have been obtained the brick batch type. Almost all the well known magnesites have been successfully used hearths and even where dolomite used for the hearth proper, magnesite tap holes are often employed. For fettling, calcined dolomite the most commonly used material and again the grading tends very coarse—material large pigeons’ eggs being specified some plants. the United States great variety fettling materi- als are employed according the geographical position the plant and the particular furnace under consideration. Thus, raw dolomite often found good enough for the fettling banks, but for more se- rious work semi-stabilized dolo- mite made adding from per cent iron oxide the feed rotary kiln preferred, while serious holes the bottom are usually repaired with magnesite either the low high lime type. The fact that Great Britain dol- omite generally preferred 40—THE IRON AGE, August magnesite doubtless due the “basic” being produced close the plants where used and very much lower price than mag- nesite. The latter usually only employed where “dead-soft” steels are being manufactured. grading fettling material must borne mind that must possess other properties than high packing density and good ability sinter. Thus, ideally the material should leave the shovel readily, show minimum segregation and rest steep angle the banks. Certain positions the furnace cannot fettled hand throw- ing, much less the machine fet- tling widely used the United States. The material dropped position the manner illustrated Fig. Most the wear new bot- tom occurs the slag line, but hearth gets older the bottom proper requires more patching. mately per ton steel pro- duced, considered satisfactory. the slags used are thin, the re- fining period long, steels being made, more excessive wear and higher fettling costs wil! experienced. (C) LIFE AND CAUSES FAILURE: The life bottom varies from tended almost indefinitely effi- cient patching and fettling, but after certain period the amount dolomite magnesite required for this purpose increases consid- erably and more economical tear out the bottom and install new one. some British plants considered good practice re- move the bottom every two three years rather than wait until shows signs serious trouble. The wear the hearth depends greatly the efficiency with which drained and this depends not only the shape the furnace, but also the temperature maintained after tapping the metal. Wherever possible metal should splashed out holes and never covered fettling since the former likely lift during subsequent melting and oxidation and start bad hole the bottom. Tap holes are generally renewed much more frequently, the tap hole proper and patch about ft. square adja- cent usually being replaced every six months. Selected analy- ses the slags responsible for the cut the slag line are given be- low: 300-ton 80-ton tilting pig fixed 1.5 2.0 MgoO 6.5 6.5 0.5 MnoO 7.0 5.0 1.5 7.5 8.0 48.0 0.5 S 0.15 Examination used dolomite bottoms shows that they (CONTINUED PAGE 106) i f ( “ft FRANK OLIVER wy ENERAL MOTORS has built new plant Lansing, Mich., and has equipped with the latest types forging machinery and machine tools for producing and 105 mm. shell high production basis. The layout extremely compact and the plant completely conveyorized, with all work process overhead conveyors. The first part the article describes the methods and equipment used for forging the shell. ° ° ENERAL MOTORS’ plant Lansing has been laid out with these objec- tives principally mind: Low unit cost, obtained through the use the latest types mass production machinery; “line” production meth- ods and complete conveyorization from start finish, with mini- mum manual handling conveyor carriers and machines; and the use double set-ups standby equipment the few places where single machine the line, ordinarily able keep with production, would become the bottleneck should fail service and need extensive repairs. The plant was originally intended for the production forgings for the Oldsmobile and Pontiac divisions, but before all the equipment could installed for this purpose the whole set-up was modified take care production and 105 mm. shell, both forgings and ma- chinings, the rate 20,000 day three shift basis. Stock comes the form ft. bars one side the building and the product leaves packed cartons the other. There still remains, however, pro- ductive capacity the form steam hammers, forging presses and heat treating equipment forge crankshafts, steering knuck- les, knuckle supports, knuckle arms and differential side gears for the automotive divisions. Besides, prac- tically all the upset forging equip- ment for shell will readily con- vertible produce automotive forg- ings when the emergency over, and great deal the machine tools installed for shell turning can converted machining such items cluster gears, bevel pinion shafts and similar transmission and rear axle parts. The plant and equipment are all new and offi- cially known the General Motors Forge Plant (Division Olds Mo- tor works). located just across the tracks from the Fisher Body Plant. Shell bar stock, which SAE X1340 steel, for mm. shell and SAE X1335 for 105 mm. shell, stored the open under over- head bridge crane and unloaded directly from gondola cars rail- road siding. Bundles bars are brought short, live roll conveyors extending through the forge shop wall and after being brought inside the building the bundle bands are broken and the single bar rolled onto power driven feed rolls for the two shears. necessary assure clean cut, avoid brittle fracture, the bundle steel placed gas fired pit the crane before brought in. This pit raises the temperature about 200 deg. Most heats steel not require this heat but are sheared cold. Two shears are used for this first operation, although one ample for work. The larger machine shearing in. bar cold although the stock for the 105 mm. (4.14 in.) shell in. bar and for the mm. (2.95 in.) shell in. bar. smaller bar shear stands alongside for emergency service. The big machine was se- lected primarily handle future automotive stock and will seen later three the upset forge ma- chines are in. size for the same reason. From the shear short slat con- veyor brings the billets in- clined rack from which they are re- THE IRON AGE, August , 7 ABOVE NSPECTION bar stock after shearing includes polishing the sheared ends the two end pieces the original ft. bar and etch- ing reveal possible pipes and seams. The monorail conveyor the background carries billet stock the hot forging machines. RIGHT for the high frequency induction heating furnaces supplied M-G set 600 and 400-kva. capacity for the 105 and mm. shell forgings respec- tively. Switchgear for the 4160- volt primary the right, while part the battery heating fur- naces may seen the left rear. leased batches three (105 mm.) time carrying cradle suspended from overhead mono- rail, the first many the pro- duction lines. Before the middle billets are released, the end billets have had polishing the sheared ends, and immersion per cent hydrochloric acid bath for min. Government inspectors check the etched ends for pipe and seam 42—THE IRON AGE, August before releasing the bar the con- veyor. From here the embryo shell be- gins its first journey over- head monorail conveyor. the shell lines there are such con- veyors, each diffierent length and with different types carrying de- vices suspended from Two serve the forging department and are common both sizes shell, while six conveyors serve the 75-mm. shell machining lines and five, the 105-mm. machining lines. the first conveyor, for example, three 105 mm. billets five mm. billets are carried time horizontal position cradle which has separate drop bottoms. This conveyor serves battery eight forging machines used for shell work. Stock chutes are placed convenient intervals this line and the billets are dumped auto- matically cam trips and roll the upset headers. Forged Upset Method Forging shell done the displacement piercing method up- setting type forging machines using multiple cavity dies. The method itself has been described THE IRON AGE, Jan. 16, 1941, pp. 25-28. For shell work General Motors Forge has assigned three 6-in. and five 4-in. forging chines. Each machine has six die cavities and five piercing and one heading tool, the work being trans- ferred hand from cavity cav- ity progressively. the process piercing the hole the shell the metal expanded that for the mm. shell forging in. out- side diameter and in. inside diameter produced from billet in. original diameter. Simi- lar proportions prevail the 105 mm. shell. When the billet placed the fifth cavity, ring that has been formed the open end the shell trimmed off. The shell cav- ity finished closely size that further internal operations are required except removal scale shot blasting and nosing in, boring and threading the open end. Induction Heating Used Heating the billet done one end time coreless induction furnaces special design. The 6-in. upsetters are served six such electric heaters and each 4-in. machine bank five heaters. Although first cost this equip- ment, with all its auxiliary ap- paratus, high, was selected be- low unit heating cost, short time cycle, freedom from and hence longer life the forging tools and less down time for changing tools. induction heating, the cycle frequency factor governing the rate heat- ing and the surface effect. The higher the frequency, the greater the induced eddy currents tend concentrate near the surface. Therefore, for heating bars large diameter, the lower frequen- cies are preferred, say 1000 cycles per sec. But since the same heating equipment will later used for automotive forgings, head- from bars small in. di- ameter, compromise was effected establishing the frequency the alternaters 1920 cycles. The 105 mm. shell calls for ex- tremely powerful electrical appara- tus. Each bank six heaters, which are operated parallel, supplied with energy from 600-kva. alternaters driven 900-hp. syn- chronous motors connected the line 4160 volts. Time heat- ing reach forging temperature 2350 deg. min. For the mm. job, 400-kva. alternaters are used, driven 600-hp. syn- chronous motors, and the heating cycle for the 2%¢ in. billets min. and sec. With battery five ABOVE displacement piercing method upsetting type forging machines using multiple cavity dies. Two shells are forged from each billet, one One the battery high frequency induction heat- ing furnaces may seen the right. LEFT HECKING duplicate sets piercing tools used the hot upsetting 105 mm. shell forg- ings the General Motors Forge plant the Olds Motor Works Division. heaters, this means one small billet will available for forging every sec. For the larger billet the corresponding time sec. One the advantages this type equipment that there little appreciable heat loss and hence little operator discomfort. Billets are charged refractory tubes which are not much larger than the stock and which have nickel-chrome wear strips the bottom. Induction coils themselves THE IRON AGE, August 1941—43 | are made copper tubing and are water cooled. The whole furnace well insulated that practically all the energy goes into heating the work. Efficiency heating 0.22 kw.- hr. per lb. metal raise from room temperature 2350 deg. has been mentioned that the bars are sheared into billets length make two shell forgings. After one end the billet heated and the first shell forged, this finished piece trimmed and re- moved from the bar mechanical press alongside the Since some heat will have been con- ducted into the unforged billet end, these crops are stacked vertically water tank with the cold end water. This equalizes the tem- perature before the short ends are heated for the second set forg- ings. Otherwise, the end near the crop may become overheated and even melt. This method permits crops reheated short time and the heat conducted out the bar that not necessary vary the power factor the heat time. should explained this point that the control heat input varying the amount power input and automatic timers each heater. The time cycle ini- tiated manual push button, and each billet pulled out, the but- ton pushed the heater for the fifth sixth blank. These timers are vernier set and are mounted the backs the heaters. Powerfactor High These induction heaters are pro- vided with two instruments the front panel the set, namely power meter reading kw. and powerfactor meter. The synchro- nous motors the M-G sets tend offset any induction loads the plant and bring the overall power- factor nearly unity. the high frequency end the unit, capaci- tors are introduced bring the powerfactor somewhere between 0.90 and 1.00. the big heaters power per heater 100 kva. and the smaller, kva. Potential nor- mally 400 volts. will also possible future automotive parts heat any section the bar de- sired changing the taps the induction coils. can readily seen that the system heating extremely flexible and capable wide application other than shell forgings. fact, the powerfactor meter chiefly useful setting the equipment for new job. Billets are handled between the heaters and heading machines tongs and counter-balancers individual overhead monorail serv- ing each machine. From the trim- ming press the shell forging placed bucket holder suspended from power driven monorail con- veyor No. parallel the first and one the longest the plant. Each carrier holds forgings, which are lifted off the back side the press avoid backtracking. Billet crops the tank the left previously indi- cated. trimming the second shell the stock, small necked down piece removed and tossed skip box. This piece will used for small gear blank, the only real scrap piece pro- duced trim ring the open end. Conveyor carries the shells the shot blast machines where the cavities are cleaned scale. There are six shotblast machines this area, two for the 105 mm. shell and four for the mm. Each blast table has four pock- ets which shell dropped open end down and hinged weight swung over the shell keep place. Shot directed into the cav- ities from underneath through noz- zles which are mechanically oscil- lated scour the entire wall surface the cavity well the bottom. This shot blasting opera- tion takes from sec. per shell. Two monorail conveyors take the shell from here the machin- ing sections. Conveyor carries mm. shell, eight carrier, and conveyor transports the 105 mm. shell its separate machining area. Capacities these conveyors and are 3920 and 2364 shell, re- spectively, total float 6284 shell. This the equivalent full shift’s production the upset forging machines. fact, these particular conveyor lengths were tween machinery but order give sufficient between op- erations. Conveyor for example, gain length without wandering all over the shop. This system pro- vides tween production rates forge and machine obviously cannot balanced ex- actly. fact, the layout Lans- ing based the plan operat- ing the forge shop three shifts and the machine department two full shifts and partial third shift. Stock process will rise and fall between the two departments but will always float the monorail conveyors These two conveyors deliver their respective cargoes the battery centering machines for the first machining operation. Conveyor carriers from this point are buckets which the shells are dropped, open end out, with axis about deg. the horizontal. this way they can pulled out with one hand and dropped easy motion down over the locating mandrel the centering machines. (In the concluding part the article shell machining General Motors Forge plant will de- scribed.) Protection for Aluminum Castings LUMINUM castings are read- ily attacked low tempera- tures condensation water va- por. order prevent this protective coating has been devel- oped. According Glyco Products, 44—THE IRON AGE, August 194! Inc., Brooklyn, has been found that emulsion paraffin wax and Flexo Wax made with dig- lycol stearate can applied easily the castings spraying the cold, leaving film water- repellent wax which protests the metal parts completely. This emul- sion has also given very satisfac- tory results extruded parts, aluminated sheets, and tin plated parts. — | re A ‘ ‘ i hard rolled copper, 1/16 thick, showing uniform grain structure. Magnification 200 2—Section annealed copper, 1/16 in. thick, showing coarse and ir- regular grain structure. Magnification 100 IG. 3—Transverse cross-section Tem- pobrazed lap joint copper, showing uniform film brazing alloy and the fine grain the adjoining metal. Magnification 100 the difficulties braz- ing copper and other non- ferrous metals the soften- ing the material due temper- ing and around the joint. When cold worked, copper has fine uni- form grain structure shown Fig. and develops tensile strength over 60,000 per sq. in. When the material softened tempering, however, the grain structure will coarsened and the tensile strength reduced less than per cent (Fig. 2). The tempera- ture required flow hard solder brazing materials, now common- used, usually exceeds the range which, maintained for appre- ciable time, effects change the grain structure the pieces being joined. Under usual methods brazing, there practical way control the temperature and the time interval with sufficient accu- racy avoid the possibility al- tering the grain structure. Electric Welding Co., Lynn, Mass., cooperation with Handy Har- man, Bridgeport, Conn., has devel- oped method controlling the Tempo- brazing the head copper hot water tank with modified seam welder. time-temperature variable order prevent grain growth and consequence loss hardness. The process (U. Patent No. 2,223,312) and employs special brazing ma- chine closely controlled current and solder low temperature flow. Amount and time heat applica- tion controlled and the operation performed resistance seam welder with suitable means in- serting silver brazing alloy the form thin ribbon between the pieces brazed. The work chilled rapidly the joint made. When cooled and hardened, the brazing alloy forms thin and homogeneous film free from irregu- larities (See Fig. 3). Tempobrazing has wide field application, covering all articles made non-ferrous sheet metal, such tanks, cans, boxes, boilers, tubing, ete. facilitates and speeds mass production. Fig. shows the process Tempobrazing the head copper hot water tank. The two disk shaped electrodes press together and turn the copper tank, while the brazing alloy led strip form between the elec- trodes and high ampere current melts and welds the material to- gether. Two nozzles provide effi- cient jet cooling water directed the joint which chills the work immediately after heat application and prevents changes the grain structure the metal. order form lengthwise seams, tubes for instance, the electrode disks are turned through deg. and run along the overlap, brazing they travel. Special set-ups have been de- signed for other specialized appli- cations. THE IRON AGE, August “ particular practice the die typing manufacturing technique the control surface conditions. essential that the die insert billet cleaned before typing operations are begun. the practice grind the top surface the block remove all and decarburized material. The block protected while the heating stage any conventional method common for such purpose. also protected, and this not all usual, while the ham- mer. 46—THE IRON AGE, August —This important method duplicating dies for forging, sheet metal work, die casting, plastic molding, great value today speed defense work. the first part the article which appeared last week, the author described features the die typing practice, steel used for dies, etc. Herein, conclusion, data are given draft angles, size limitations, hammer technique, etc. Protection while the billet be- ing heated given covering with sheet metal cap, heating gas flame that sulphur-free, —on very small dies—putting the billet sealed tube container. the forging hammer, the hot billet covered gas flame which completely surrounds the bil- let and burns over its face pre- vent oxygen reaching the metal. The greatest perfection sur- face finish attained the typing dies has been through the use 0.001-in. nickel plating. This im- provement the basic practice calls for plating the clean die steel billet with nickel before heat- for the typing process. Hardness Finished Die The desired hardness the fin- ished typed die attained heat treating after typing, conven- tional. The practice calls for hard- ness 418 477 Brinell dies for light forgings like connecting rods. For heavier forgings, hard- ness ranges from 321 387 Bri- nell. The stamping dies, depending upon the particular job, have Hardness, course, depends upon the kinds steel used the die and the kind material being forged. Draft Angle and Shrink mystery attaches the draft angles shrinks involved this upsetter gear die Erie ham- mer. The retainer block with master die insert shown mounted the hammer. Below the billet hot die steel another retainer block the bed the press. Gas flames are kept playing across the sur- face the billet scaling, and etween hammer blows the work daubed with soluble oil and water. The hammerman's helper uses air blasts blow loose scale off the pro the int nec reg 3/] cor des tic Speed Production ... process. Draft angles are much the same those ordinarily ap- plied and require only reasonable intelligence their application. Shrink, double triple, may required the circumstances, based upon requirements the finished forging. For instance, con- necting rod forgings employ the regular commercial shrinkage 3/16 in. per ft. The typing die in- corporates provision for in. total shrink and the master-master die designed with 9/16 in. total shrink. This typical die typing prac- tice. might remarked here that per cent the die typing work done, both female master and male master (master-master and typing master) die are re- quired. However, stances dictate, only male master used; for instance, this has been proved possible the manufacture dies for ring gears and other simple shapes. Kinds Dies Among the kinds dies and molds used industry large quantities are the following, all them subject economical manu- facturing the die typing process, including some the sheet metal stamping dies and upset dies: Forg- ing and flash trimming dies; blank- ing, drawing and sheet metal trim- ming dies (with size limitations) cutting and shearing dies; upset dies; plastic molds; dies for injec- tion molding; permanent molds for steel casting; dies for centrifugal casting, for steel gears; dies for die casting; glass molds; molds for ceramics (such for decorative brick) header dies, etc. Size Limitations Practical size limitations have ft. For instance, mold for plas- tic steering wheel has been die typed from billet in. this billet 18-in. cavity SHERMAN Detroit Editor, The Iron Age was typed. was held within limits dentally, may general in- terest note that, 102 dies typed from one master, only two production dies were scrapped. Another example size the typing die for camshaft in. long. The billet for this insert was in. length and about 4x6 in. cross-section. Size Presses Smaller dies have been typed punch presses 400 600-ton ca- pacity but for the manufacture larger dies, especially those for forging and upsetting, steam ham- mers 2500 5000 rating are used. Hammer Technique, Timing Control Through experience there has been worked out accurate time- temperature control for size the finished die. All the billets are heated exactly the same temper- ature (shrinkage figured from the top base line 2250 deg. F.) and the hammer man controls the final results the length the time “works” the die. Thus, since takes large piece steel longer cool than small one, the ham- mer operator prolongs the work larger dies the timing the hammer blows get the desired result. All the factors are ac- curately plotted chart and the IG. 9—At the right are two separate die inserts for the Ford connecting rod. These are the male master inserts cameo-like relief just they are removed from the retaining block after typing with the master-master dies. The one the extreme right the finisher master die, while the one near the center the photograph the blocker. These would finished the die shop, holes drilled around the outline the part for venting, described the text, lettering such the word put the die insert, and the insert would squared for inser- tion retaining block, shown Fig. 10. this state they would used single die type the female production die shown the left the “as stage. THE IRON AGE, August 1941—47 > operator knows before goes work just what the timing must give him the desired results. appears times that the ham- mer man juggling get the de- sired results, but actually working the exactness stop watch; for instance, certain die may aiming exactly sec. attain the desired sizing, and for that purpose spaces the sides squaring the bottom and ma- chining the four sides the trim die, filing the cutting edges template before the hardening op- eration. The time saving this method great compared with the standard practice forge shops making trim sections, mounting them shoes and doing lot filing and precision grind- ing obtain accuracy. complete male master die retaining blocks. con- sists the blocker die insert left and finisher die insert right, mounted single retainer block after being prepared the machine shop and after annealing. ready now for use type production die inserts, shown the left Fig. (As can observed, this connecting rod design different from the one shown Fig. 9.) blows far enough apart get the final blow driven home the in- stant indicated his control chart. Typing Trim Dies Dies for trimming the flash from forgings are typed manner similar that already described but the technique warrants special description. this instance, the master die, typing die, pierces the correct opening the trim die. The only work necessary, be- 48—THE IRON AGE, August 1941 Conventional trim dies when they become dull must removed from the press, shoe and all, and sent the die room have the sections removed and replaced sharp sections while the dull ones are repaired. This involves the ser- vices die set-up men and takes least two hours during which the production press idle. Typed trim dies have consider- ably longer life than the conven- tional ones because the cutting edge continuous, eliminating the joints which failure prone occur. addition being made one piece, the typed trim dies are holes are drilled the bottom the trim die serve locating points for mounting the trim die section the base plate. When the die dull, not necessary remove the shoe from the press. The operator merely loosens two three clamps, lifts the die off and replaces with sharp one, using dowel pins for locating. The aver- age interruption production only about min. and die set- man required for the job. Reworking the old section usually done after several them have accumulated. They are “staked in” the blacksmith shop, are reheated, restruck the master die and swedged out size; then they are filed again template size, the bottom surface machined and dowel holes drilled, and the dies are ready for use again when- ever needed. Time Saving Typing Most important feature the die typing process the great sav- ings time that can accom- plished through its use. This time saving can translated terms direct cost, increased productiv- ity the plant, combination the two. Since there great deal variation the time required make various dies, only pos- sible here indicate the nature and amount the possible savings. The ordinary die probably takes the toolroom. This time depends upon the complexity the die de- sign and the use which the die put. The more complicated the die, the greater the savings the typing method, for easy type intricate pattern plain one. There more time used the master-master die com- plicated, but not more than would used the toolroom sink one conventional die. dies, the master-master die usually requires more time for cut- ting than required type all the other dies the lot. re- peat orders, the time element for typing inconsequential. identical dies that ordinarily would cost 2000 man-hr. time the tool- room for die sinking, can done 2 ao man-hr. (three