The Iron Age 1945-05-10: Vol 155 Iss 19

and Advertising Offices Gast 42nd St., New York U.S.A. BAUR Vice-President General Manager Vol. 155, No. May 10, 1945 LEONARD Assistant General Manager Reader Service Market Research CLEARY, Technical Research and 2420 Ave. ° Owned and Published CHILTON COMPANY (Incorporated) Features Chestnut and Sts. GEORGE GRIFFITHS This Industrial 108 JOHN BLAIR MOFFETT, Secretary Additional Warehouse Officers 122 WILLIAM VALLAR, Asst. Quarter’s Output Tops 124 ° ° Construction Machinery Committee Formed 130 Canadian Production Limitations Clarified Henderson Returns From China Member, Business Papert Machine Tool Market Developments 144 Nonferrous Metals News and Prices Iron and Steel Scrap News and Prices Comparisons Prices Week and Year Finished Iron and 152-153 the Arts Index. Warehouse, Semi-Finished, Steel Prices Stainless Steel and Ferroalloy 162 a 3 2 a a q = ¥ ter CONSERVE THE HAVE! you follow few simple rules now, you can avoid critical tool situation your plant. Handle all your present carbide tools with ‘em right—and they will give better service, all that asked them, and enable you meet your greatly increased production schedules. For practical information how best conserve your carbide tools and save delays, get touch with Firth-Sterling. STEEL COMPANY You GET KNOCKED AKE Keep Your Carbide Tools the Fight RULES THAT CONSERVE TOOLS HANDLE CARE Carelessness may damage cutting edges. dull edge slows production. Find out the right way—and it. 62—THE IRON AGE, May 1945 OFFICES: PA, YORK - HARTFORD » PHILADELPHIA - PITTSBURGH - CLEVELAND DAYTON DETROIT - 408 ANGELES ESTABLISHED ° ° May 10, ° ° VAN DEVENTER President and Editorial Director BAUR General ° Editorial Editor ......... OLIVER Commercial Editors WINTERS ALBIN JOHN ANTHONY BARMASEL Assistants SCHIEN VAN CAMP HANSEN DAVIS Pittsburgh 428 Park POST MOFFETT DONALD BROWNE EUGENE HARDY Washington Press LLOYD Cleveland 1016 Guardian Detroit Woodward OSGOOD MURDOCK Francisco Market Correspondents ROBERT DEAN Buffalo Boston HUGH SHARP Milwaukee SANDERSON Toronto, RAYMOND KAY ~Los Angeles JOHN McCUNE Birmingham ROY JAMES DOUGLAS Ants Sing these days man and woman-power shortages one fortunate able get into hospital and course doubly able get out again. putting 1945 down lucky year. Twice hospital and twice out: First, two months ago with pneu- monia and again, week ago after car collision with ten-ton truck, with nothing more serious show for than broken wrist and couple cracked ribs. this has been written the country among the birds, the bees, and the broadcasts from San Francisco and with plenty time think about these and other things. The San Francisco happenings have made think about the ap- parent disadvantages democracy and the superior efficiency regi- mentation when comes getting things done neatly and quickly. There are differences opinions and interests this World Security Conference and going take some time and some doing reconcile them. How much simpler would the delegates would just hold election and choose one man World Boss Supreme Dictator then they could all adjourn and home and leave him issue order. Instead choosing this simple and easy way, however, these rep- resentatives from all over the world have taken the hard road cooperation contrasted dictation. Evidently they believe that while this will require good deal giving-in and giving-up all hands, the hard road may make easier traveling for the generations that will come after them. After all, efficiency world relations well industry and business must measured over the long term and not the short term. may that you can get something done more quickly ordering done, you are position order, than taking the time and effort convince those who are that should done. But action without conviction not likely lasting whole-hearted that based upon belief rightness objective and method. Alfred Sloan, Jr. who certainly has demonstrated the ability get things done, once said that would rather spend hours convince executive the rightness proposed policy action than save time issuing “unsold” order. That seems sound doctrine not only for World Security delegates and industrialists but all the way down papa and mama family affairs. nature, the birds have, think, done better than the ants working out cooperation under democracy. They agree act group when necessary periods migration but the interims the indi- viduals are free the air. The ants probably accomplish more than the birds when comes work. They march regiments and build communal homes which they sleep after twelve fourteen-hour days labor. But ants don’t sing and birds do. Mai slows LES TI- IRON AGE, May 1944 J erence b metal and applied directly the dinary enamelin (below). you manufacture buy porcelain enameled products? Then you should know about the remarkable advantages the new enameling alloy steel—Ti-Namel—the most recent development Inland research. YOU ARE Inland Ti-Namel Steel eliminates the necessity for ground coat porcelain enameled products. White color cover coat vitreous enamels are applied direct anager, and the base does not age strain. can tion and Inspec easily deep drawn. reduces shop reoperations, coat edging, and scrap. does not reboil. fired lower temperatures, and shorter time. Inland Ti-Namel Steel increases shop output, lowers manufacturing costs, and assures better enameled products. YOU ARE BUYER PORCELAIN ENAMELED WARE. you specify Inland Ti-Namel Steel you will get enameled products that are unsurpassed, the finish being equal the best multi-coat ware. The thin finish coat coats applied direct the base metal, will have high reflectance, reduced damage hazard, and longer service life. Write today for your copy the new Ti-Namel Bulletin! Pending patent applications the new enameling process and product made thereby are owned jointly Inland Steel Company and The Titanium Alloy Manufacturing Company under trust agreement. inches This deep drawn deep, was Inland Steel Company, Dearborn Street, Chicago diameter Ti-Namel Sales Offices: Cincinnati, Detroit, Indianapolis, Kansas City, one coat Milwaukee, New York, St. Louis. St. Paul. enamel. Principal Products: Bars, Floor Plate, Piling, Plates, Rails. Reinforcing Bars, Sheets, Strip, Structurals, Tin Plate, Track Accessories. about this combir nesses ness. the invest contro The aximur Stz WHAT FOR You repor malle terial rated ess emain ong onsid those pla utput News Front May 1945 Appointment Dr. Mahoney, the University Utah, assist the Property Board the disposal government owned steel plants regarded the wind indicating that Steel will wind owning the Geneva, Utah, Samuel Moment, appointed the same time advise aluminum plant reported favor increased competition the light metals field. Suffering second quarter relapse, steel production France has dropped about per cent capacity, following much stronger start earlier the Estimates are that coal production continues about per cent capacity. Conflicts are foreseen the planning WMC, OPA, and WPB for the days said have put men relief rolls already. Fighter plane design thinking, already 100 per cent converted gas turbine pulsion, now accepting that radio control will replace the pilot this field. Tests this country prove the complete controllability such siles, with entirely different type system than anything used the Plans now being made call for conversion bombers, well fighters, turbine propulsion. Such applications will probably geared combinations rather than the pure jet systems now use fighters. Indian Purchasing Mission, long awaited this country nesses, and headed Tata and Birla has been delayed Mr. Tata's ness. The group now London and appears that late May early June will approximate their arrival the United States. Coming private group interested the overall industrialization the combine represented stated have unprecedented sums Indian money invest American equipment, bought complete plants. Their plan for control remain the hands native Indians. WPB has been soliciting civilian manufacturers, fabricators and particularly maller plants place orders and indicate requirements for conversion tools and terials for civilian production. apparent that the CMP system will dwindle, leaving only highly rated (must military) orders and (compulsory civilian) requirements. Any essential producer will fill these first and free what wishes with emainder his production Machine tool orders are reflecting the fact that railroad shops have embarked ong overdue rehabilitation work. Farm implement manufacturers indicate that are sizeable retooling for new models. The heavy shell program embracing 240 mm. and in. shells being cut back cent this week. May meeting the 105, 90, 81, and mm. hell and the mm. mortar programs scheduled per cent cut back those lines. The tungsten carbide shell core program will involve totai plant and equipment expansion, and will use total times the total utput tungsten. the expansion program, the Carboloy Co. will build least two $6,000,000 Fragmentation bomb programs are also being heavily cutback, but easement high explosive bombs and rockets foreseen the near future. The new wage.scale plan adopted the Reynolds Metals Co. plants y., Will permit workers achieve top rate pay after only months. aximum rates were attained after some months service. Starting rates being 85c. hr. depending job classification and | q 3 q | q q 4 | | Siberian Institute, Theoretical considerations confirmed experimental results indicate that the energy consumed cutting primarily made work done plastic and elastic deformation. With increasing speed metal tends behave more and more brittle mate- rial, with plastic deformation and hence energy consamption be- coming less and less. Turning tests steel 4900 per min. showed little heat was generated. Cast iron and aluminum behaved like brittle materials when milled high speeds, while carbon steel and copper did not. The original article appeared the Russian journal, Vestnik Metallopromyshlennosti, 1940, No. and was translated Tania Cosman. desire speed the cut- ting metals from few tons surface feet per minute hundreds and even thousands feet per minute not new. However, spite the importance this prob- lem, not single physicist has thor- oughly investigated this problem and contemporary research engineers have hardly this sphere. But recent results experiments plas- ticity and hardness metals may put the science cutting metals entirely new basis. The author has studied plasticity and hardness metals for many years, but mainly concentrated alloys, chemical compounds and po- rous metals. the course this re- search, however, formed very definite idea the processes taking place hard metals during their The study the ties hard substances when sub- jected dynamic stresses, developed the possibility surface cutting metals rate several thousand feet minute. The problem can ap- proached equating the work done the cutting tool the energy ab- sorbed the work and chips, thus: (1) Where U=the energy used when the cutting tool removes chips from IRON AGE, May 1945 the surface the metal stress the cutter cutter with respect the work Energy can divided into four parts: U — +U; +U; +U, (2) Where energy dispersion ormation energy elastic defor- mation The first part the work done bringing the surface quantity molecules from the body the machined metal producing down the continuous metal form plurality small particles, thus increasing the total metal surface. Chips break apart the process cutting, creating new surface. When the chips break off, further surfaces are formed the work. Finally the chips wrinkle and the surface grows even more. Energy must supplied for all these pur- poses. evident, however, that energy plays insignificant part the total energy used the machining. Even coarse metal cast iron where chips break into very small particles, this energy consumption negligible. 1929 Gruda and the experimented the mechanism cutting. order reduce this in- vestigation the most general level, rock salt was used the experiment. was shown that the work amounted only 0.12 7.0 per cent total work even when as- sumed that chips were composed only molecules NaCl. For en- gineering metals energy can completely disregarded because the majority such metals and alloys have much greater plasticity than rock salt. Plastic Deformation The second part the energy consumed during cutting the plastic deformation the metal. the working hard substance plas- tic deformation begins when the lim- iting stress hardness fluidity reached. The deformation consists changing the lattice structure the molecules, reducing the size and changing the structure the crys- tals. Plastic deformation non- reversible process which usually ac- companied development heat. was shown experiments carried out Fedorov the Siberian Physico-Technical Institute when metal cylinders are compressed plas- tically, all the mechanical compres- sion work goes into heat (for instance the case lead and copper 100 per aluminum per cent and tin per cent). the cutting metals, plastic deformation takes place immediately front and under the cutting tool. reaches considerable depth below the machined surface. the present time the author with group co- workers studying plastic deforma- tion cutting, applying the method ° of for pla: que: dep the nun chin stea stre ture grai sult crys mor forn into chin chan the the plas tion duce the whic mati anne prod shou pure some diam the grair layer grair the prior the plas- lim- ity sts the and crys- non- heat. arried berian when plas- stance per tin plastic diately tool. below co- forma- method formed such manner that the (Fig. 1). The zone plastic defor- mation, therefore, deepens constantly. the thickness the chips 0.118 in. depth, the zone plastic deformation the aluminum reaches the depth 1.18 in. Conse- quently the deformation reaches depth which times greater than the thickness the chips. order remove any possible in- ternal stresses the case alumi- num the specimen was annealed for hour 450 deg. C., then was ma- chined and later annealed again. In- stead plastic deformation internal stresses were set up, the lattice struc- ture the crystal changed and new grains came into existence. re- sult this recrystallization, large crystals whose linear dimensions were more than 0.4 in. (Fig. were formed under the cutting tool. The plastic deformation spreading into the body the metal being ma- chined produces grain growth and changes the mechanical properties the metal considerably. The size the grain depends the degree, plastic deformation. Fig. the x-axis gives the amount .deforma- tion and y-axis the grain size pro- duced. certain deformation the grain size does not change the process annealing. Then there sudden increase grain size which decreases again the defor- mation increases. When plastic def- ormation becomes very large, after annealing fine-grain structure produced. order obtain coarse grain structure iron, deformation should amount 2-4 per cent. pure iron the size the grain can sometimes 0.4 in. and more diameter. Immediately under the tool consid- erable deformation takes place and the process annealing grain structure appears. Below this layer there zone with large grains and then third layer which the structure the same was 1G. 2—Annealing plastically de- curred very small. order investigate the influence the cutting speed the depth penetration plastic deformation aluminum disk was milled rate 4900 surface ft. per min. Then this speed was gradually reduced zero. Chips were 0.118 in. thick. Fig. shown section after annealing and etching. the point where the milling speed was 4900 surface ft. per min. the depth recrystallization was small but with decreasing speed the depth increased. show the effect plastic defor- mation the mechanical properties given material, extensometer readings were made specimens identical shape, one which had been peened, the otHer not. Completely different stress from the two samples. The one which had not been peened was machined high cutting speed and light feed, producing fine chips, and resulted diagram Fig. which typical for plastic deformation. This sample has normal yield limit and average elon- gation. The other, peened sample which was machined slow speed and heavy feed, giving heavy chips, produced diagram Fig. indicat- ing increased yield limit and corre- spondingly lowered elongation. The influence the working method especially strong when the 3—Effect the amount defor- mation the grain size the nealed metal. Grain size Deformation, chip which constantly increases size. size, 0.4 in. part subjected thermal processes after machining. During annealing peened part, for instance, may de- velop big grains and completely dif- ferent properties. Thus that part the energy which used for plastic deformation and which al- most entirely expended anneal. ing effect. Frictional Energy The third part the energy used friction and denoted U;. In-spite numerous experiments the field friction there still clear conception the physical na- ture this phenomenon. seems dispersion and plastic deformation. When train moves along the rails, for example, they are being worn out, their surface dispersed, flattened out, and plastically deformed. The deformation especially pronounced the slipping the braked wheels. Electromagnetic methods experi- menting show that there appears the rails strong deformation peening. where the work used for dis- persion and for plastic deforma- tion. Heat always generated fric- tion, although often wear plas- tic deformation occurs. analo- gous action takes place rubbing two brushes against each other spring. can explained the following way: Supposing that one end resil- ient rod fixed position, applica- tion force the other end bends the rod. the stress suddenly re- leased, the rod will move and fro, and potential and kinetic energy interchange constantly. inner frictional nor outside gravitational forces were acting, the rod would never stop moving. But due inner friction the stored-up energy the rod transformed into heat and raises the temperature the rod. The- heating brushes rubbing follows similar pattern. similar process also takes place the ma- THE IRON AGE, May 10, 1945—67 ism vel, ent. cent as- the lloys than chining metals. When the tool moves over the work elastic deforma- tions take place which change into vibrations and finally into heat. Elastic deformation the fourth part the work done the tool and results the generation heat. Since the work friction can subdivided into and (formula 3), part can joined with and with formula (2) which now becomes (4) Energy may disregarded, the energy spent dispersion insignificant part the total work, leaving the equation U = U: + U 4 (5) Thus the basic factors are energy used plastic deformation and energy elastic deformations. Obviously cutting such plastic met- als lead, tin, aluminum, copper, iron and soft steel, all which have low yield limit, energy predomi- nates; the cutting such brittle metals cast iron heat-treated steel, energy predominates. Cast iron machined more easily than soft steel; brass and bronze, more easily than copper. general brittle metal machined with greater facility and gives out less heat than plastic one. When consid- erable plastic deformation takes place, energy will consumed much greater extent than used elastic deformation. Energy the main cause heat occurrence and impedes the cutting metals high speed. When iron steel being cut the rate 200-600 ft. per min. heat pro- duced such rate that the chips get red hot. make the cutting metals possible high speeds the plastic deformation energy should greatly diminished. Relative Plasticity Prof. Eoffe and his colleagues showed that the yield limit rock salt dependent the temperature —the yield limit drops zero (Fig. curve 1), when the- melting point rock salt reached (800 deg. C.) which was proved X-ray diffrac- tion patterns. the same time was shown that its toughness constant and does not depend the temperature. From point view the imipact strength can only depend small degree the temperature. The curves and in- temperature 200 deg. rock salt stressed tension tempera- tures below 200 deg. C.. breaks 68—THE IRON AGE, May 1944 without plastic deformation and acts like brittle substance. higher reached first and plastic deformation occurs before the final break occurs. series tests demonstrated that curve not absolute entity. The yield limit depends the rate ap- plication the stress. slow rate such extent that even salt behaves 4—Showing how depth plastic deformation related the speed cutting. Deformation least the highest speed. ° ° ° like plastic substance tem- perature. Dynamic stresses applied high temperatures (500-600 deg. C.) will cause salt act brittle sub- stance that its yield limit in- creased. The dependence yield limit the temperature slow rates Fig. and high rates deforma- tion the curve curve the point intersection with curve closer the lower temperatures and curve closer the higher cnes. typical example pitch which lique- fies under the weight its own body and runs out the spout. plastic substance under very low rates deformation, but struck with hammer, pitch breaks with- out any plastic deformation, acting like brittle body. Speed vs. Plasticity Every liquid viscous plastic body, but high speeds even liquid can transformed into brittle Water flows around slowly moving oar, but moved rap- idly break occurs. Recently paper was published whose authors proved this They made mixture transformer oils different con- centrations and rosin. The jetting spray this mixture was interrupted bullets low caliber guns fingers attached rotating disk. was proved that when the bullet trav- eled 1000 ft. per sec. the spray was rendered brittle any viscosity from poises. liquid with vis- cosities from poises becomes brittle when interrupted small ob- jects the speed ft. per sec. The conception and plasticity are relative. The higher the rate stress application, the sooner plastic metal approaches brittle condition and the less suffers from plastic deformation, the size which depends the continuity the stress. However, some metals like lead and copper are difficult render brittle even under very high rates deformation. well known, lead bullet even the speed 2600 ft. per sec. does not disintegrate when hits target brittle substance would, but flattens out, keeping its plasticity. The method reducing the value formula (5) consists the possibility cutting extremely high speeds several thousand feet per minute several hundred feet per second. The higher the cutting speed, the smaller the plastic defor- mation and heat quantity generated. great cutting speeds, the energy expended only dispersion and elastic deformation. Plastic energy consumption such high speeds cutting eliminated. This was taken into consideration Stress Deformation 5—Stress-strain diagrams for unpeened sample and (2) peened specimen. when the following experiments with high surface speed cutting were car- ried For the experiments heavy lathe was constructed from circular saw. The lathe weighed about tons and was equipped with casters. the first series experiments, cylinder soft steel was turned circumferential speeds 4900 7200 ft. per min. Tool feed was 0.008 in. per rev. high speed steel tool was used. High Speed Tests speed 4900 ft. per min. the following was observed: the begin- ning the experiment when the edge the cutter was sharp, the chips were almost cold, very smooth and easy flowing. The surface the work was free from defects and smooth. The 14.5 kw. operated easily he se su ac sh: toc J sme cha hig! mal due Whi ishi 7 q ned with } Car- ighed with nts, was steel in. the begin- edge chips and work easily under the load, although according previous calculations its power should have been insufficient for the cutting proceed under normal speeds. The chips furthermore showed traces burns. This confirmed the previous conception that less heat produced high speeds cutting. After ma- chining the cylinder over length 1.96 in. which corresponded sq. in. area, the cutter was worn out and produced further chips. When the speed was reduced, the chips were heated and changed color from straw-yellow blue-violet. the speed 4900 ft. per min. the tool remained keen only for few seconds. After the experiment the surface the cutter conformed ex- actly the surface the cylinder which had been previously ground low speed. The worn-out part the cutter was exact negative the surface the cylinder and the shape the last-produced chip was imprinted exactly the cutter. speed 7200 ft. per min. the tool life was almost zero. The tool Relative yield strength toughness 400 600 800 1000 Temperature, deg.C. F's. yield strength temperature rock salt. ° smoothed out immediately without changing the surface the cylinder. interesting note that under high speed cutting change occurred compared with nor- mal cutting performance. The chips, due the high speed, were thrown good distance away from the tool. When the cutting turned into pol- ishing effect the tool, the usual sparks occurred. Thus the first series experiments led the conclusion that possible sharpen high speed steel cutters rapidly rotating cylinder soft steel. The same cylinder also quickly and effectively polished cutters made from hardened steel and work was done the cylinder. (To polish the tools part the cylinder was made cone shaped.) Milling Experiments The experiments the second se- ries were made with rapidly rotat- ing milling cutter. one the ends the cylinder was attached disk cut out ordinary circular wood- saw and sharpened the circumfer- ence. The diameter the cutter was 14.5 in. and its teeth were cut with triangular file, the pitch being 0.118 in. This circular saw made 1450-2000 and the circumferential speed was 5600-7500 ft. per min. The depth cut was 0.02-0.05 in. and the table feed 0.008 in. per tooth. Milling performance was distinct from machining lathe. The stream sparks produced milling showed that there marked tem- perature rise. paper, placed under the lathe collect the chips, was burned several places indicating that the chips were hot. blue steel powder collected the sheet, among which were some round particles that were from 0.015 0.020 in. diameter and several clusters chips which had gradually curled upon and stuck the edge the cutting disk. Curlings with diame- ter 0.008 in. stuck together and formed clusters. the machining the steel the surface was heated and the hardness the steel increased. Experiments were carried out also with cast iron and non-ferrous metals. The most effective was the experi- ment which cast iron slab was machined rapidly revolving mill- ing cutter. The table feed before 7—Relationship impact speed (stress) and deformation for 0.20 per cent carbon normalized steel. Impact speed,meters per sec. per sec.according Charpy was in., the cutting depth be- tween 0.02 and 0.10 in. The results the operation depended the qual- ity the cast iron and were very varied. the machining cast iron slab one quality, pronounced development deep red sparks oc- which did not fly very far and were almost drop-shaped. Another kind cast iron yielded practically sparks. the point cutting there was dark red streak indicat- ing that the metal was being locally heated. iron was smooth and clean, resem- bling polished surface. The machining non-ferrous metals, such copper, brass, alumi- num and zine, produced sparks. The copper surface showed signs warping several places after ma- chining. The surface all the other materials was very smooth. The chips from cast iron were powder with grains 0.04 in. and more diameter. The chips from brass were mixture powder and curlings. Copper produced chips those steel—i.e., bent chips 0.4 in. sq. which resembled welded wires. Aluminum shavings consisted powder and rather big particles these experiments the teeth the milling cutter were hardly worn the machining constructional, and even hardened steels, although the cutter was made from rather soft steel which was easily sharpened with file. Experiments showed that circumferential speed 6500 ft. per min. about 110 ft. per sec., steel and copper not reach brittle condition. They need higher cut- ting speed. The relationship Letween the me- chanical properties normalized steel (0.2 per cent and the rate deformation was investigated who built special ro- tating stand which had circumfer- ential speed 330 ft. per sec. Fig. shows the results arrived at. The x-axis shows the speed and the y-axis shows the degree tion when sample cut right angles. The curve shows that plastic deformation this normalized steel stops when the speed approaches 165 ft. (50 meters) per sec. Consequently, make the machining the steel easy that cast iron, the machin- ing speed would more than 10,000 ft. per min. The third series experiments was made with high speed milling each having from one 10, The machined face the’ m its eet or- ed. ris eds M Deep Drawing Magnesium Alloy Sheets Tests made three grades magnesium alloys indicate that reductions blank diameter from per cent are possible cupping operations performed double action mechanical presses, provided the material heated 500-550 deg. redrawing shells, reductions per cent are possible, giving overall reductions 77.5 per cent. tre- mendous increase the production aircraft dur- ing the last few years has re- sulted ac- demand for light weight parts fabricated from magnesium al- loys. This increased demand has re- advances the fabricating mag- nesium alloys casting, forging and press forming. For most sheet metals and alloys, forming and deep formed room temperature. parts requiring severe forming drawing are made two more draws, anneals are generally required be- tween draws because the work hardening that takes place. some eases sheet products also require special low temperature anneal for the relief residual stresses which would cause eventual failure the finished part. TABLE WEBER Chief Metaliurgist VANDEN BERG Metallurgist The Aluminum Cooking Utensil Co., Subsidiary Aluminum Co. America Because the magnesium sheet alloys have limited capacity for cold work room tempera- ture, the forming and deep draw- ing magne- sium alloy sheet are usually carried out elevated temperatures. Consequently, order for deep drawn magnesium alloys sheet products produced success- fully the drawing tools must main- tained suitable hot working tem- perature. Hot drawing magnesium alloy sheet has the advantage high reduction per draw without the use intermediate anneals. Drawing Alloys The various magnesium alloys are available variety commercial forms such extruded bar and shapes, castings, forgings, sheet and plate. The sheet products are sup- plied three standard alloys, the products the American Magnesium Alloying Constituent, Composition and Mechanical Properties Commercial Magnesium Alloy Sheet Mechanical Properties Tensile Yield Strength, Point, Elongation, Per Cent* 1.5 1.5 0.3 2.7 6.5 0.2 6.5 0.2 | 32,000 17,000 1.0 42,000 0.7 35,000 Magnesium and normal impurities constitute the remainder. 70—THE IRON AGE, May 10, 1945 Co. being designated and AM-C57S hard (as rolled) temper, and soft (annealed) temper. The alloy used for moderately stressed parts requiring good welding properties. has greater strength than but not readily torch welded. The AM-C57S alloy has greater strength than AM-C52S, but not easily torch welded AM-C52S. Table contains the nominal compositions and typical mechanical properties the annealed and hard tempers the sheet alloys AM-3S, AM-C52S and All three alloys have relatively high resistance corrosion and can readily fabricated forming deep drawing provided the tools are maintained proper hot working temperatures. Simple shallow shapes produced from annealed sheet forming drawing room tem- perature provided the radii are liberal and the reductions are not too large. Hydraulic presses generally have been recommended for severe forming and deep drawing magnesium sheet alloys they have slow, uniform punch stroke. Normally, mechanical presses have higher punch speeds, which means increased production rates. However, these higher punch speeds might increase the possibility fracture during the initial stages the drawing process. data have been presented substantiate these claims and they seem based mainly opinion rather than perience. order obtain data the practicability using mechanical pre she con pre dra 125 an eTa | stri gin to mil | we) ing the ria wa | } 0.0 dri thi pre m: te: re pe ill pl presses for deep drawing magnesium sheet, series drawing tests were conducted using double-action toggle presses. All tests involving only one draw were made toggle press 125-ton capacity. This press was op- erated its normal speed strokes per min. which gave max- imum punch velocity ft. per min. The punch velocity the be- ginning the draw was calculated approximately ft. per min. The blankholder and punch used for these tests were made from mild steel and all working surfaces were polished. Press tools for draw- ing magnesium alloy sheet are usually made mild steel, although heat re- sisting cast irons have been used. Punches can made from steel, cast dimensions must made for the ex- pansion elevated temperatures the magnesium and the tool mate- rial. The clearances between the punch and die room temperature was 0.078 in. when drawing sheet 0.064 in. thick, and 0.054 in. when drawing 0.040 in. sheet. Although this clearance may appear large, produced shells with little wrinkling provided proper blankholder pressure was used. Gas ring burners fastened the die and blankholders maintained the tools the various temperatures used the drawing tests. The punch was not heated di- rectly burners, but reached tem- perature range 150 350 deg. depending upon the temperature the die and blankholder. Fig. shows the general arrangement burners and tools. The setup shown was used double draw test determine maximum reductions, but serves illustrate the general arrangement used. die, Tool Lubrication The proper lubrication the tools the high temperatures necessary for deep drawing presents somewhat problem most the common lubricants ordinarily used room temperature decompose under heat, leaving gummy carbonaceous resi- due the working surfaces, Several pigmented mixtures were tried, but they generally carbonized, leaving gummy residue the tool surfaces. drawing lubricant consisting per cent (by weight) flake graphite Suspended mineral oil-tallow mixture proved satisfactory. Flake graphite alone may used lubri- cate the blanks, but must sus- pended volatile solvent that can applied brush spray. The use graphite considered For other data the draw- ing magnesium alloys the read- referred the following articles which have appeared Tue Ace: “Hot Forming Magnesium Alloy Sheets,” Resos, Consolidated Vultee Aircraft Corp., July 27, 1944, 42; and “Deep Drawing and Form- ing Magnesium Sheet,” Arthur Meyer, Meyer Sheet Metal Machinery Co., 30, 1944, 44. film which will withstand the temperatures necessary when drawing magnesium sheet. deep Although graphite excellent drawing lubricant, objectionable because the cleaning difficulties introduces. The graphite has ten- dency embed the soft magnesium surface which makes difficult remove. Usually alkaline solvent degreasing will remove the major portion the drawing lubricant and chromic acid 150 deg. will gen- erally remove all traces graphite. essential that the shells cleaned soon possible prevent pitting caused galvanic action which might take place under certain conditions where the graphite em- bedded the surface. Further tests drawing lubricants revealed that mixture high flash- point oil consisting asphaltic still residue and black oil with 0.75 mica added per gal. gave satisfac- tory lubricant for heads. The vehicle oil this mixture viscosity 20,000 sec. 100 deg. The mica very fine and the type used for anti-friction surfaces high temperature. The lubricant was used for temperature 500 deg. and did not form objec- tionable residue the tool surface. 600 Tempera- ture, Alloy Specimen From Deg. AM-3S 700 AM-3S 700 AM-3S-H Hard temper sheet. AM-C52S Sidewall......... 600 AM-C57S The surface condition the shells was satisfactory and lubricant could completely drawn shells washing mineral spirits benzine. removed Commercial magnesium sheet alloys AM-3S-0 and AM-52S-0 0.064 in. thickness for the liminary tests determine approxi- mately the maximum reductions blank diameter that can made single drawing operation. This pre- liminary test were used pre- unusual types failures other than the char- acteristic fractures which occur when cold drawing metals. These two types failures are shown Fig. disclosed two +har owner The angular fracture occurred ~ ~ flange and the area adjacent flange. This fracture occurred when the tool temperatures were too low for the reduction attempted. The other type failure occurred the lower area the sidewall the tom the shell when the tool tem- peratures too high. room temperature the blanks would shatter into number pieces the re- bot- were ductions attempted were too great. The data obtained from this pre- liminary test indicates the following conclusions: 1—The pressure should maintained possible and still avoid wrinkling. low 2—The approximate maximum reduction blank diameter that possible room temperature was per cent for the AM-3S-0 and per cent for the AM- 3—The approximate maximum reduction blank diameter that possible 550 deg. for AM-3S-0 was per cent and per cent for AM-C52S-0. 4—Magnesium alloy 0.064 nhickness in. and rough she scratches, TABLE Mechanical Properties Deep Drawn Magnesium Mechanical Properties Tensile tion, Lb. per Per Cent Sq. In, 63.6 32,400 17,600 18 36,000 27,000 | 46 ,000 34,000 10 } 59.0 44,200 33,600 q 61 : the the are ing ral surface defects such slivers, ave ing ical ave -|- the THE IRON AGE, Moy 10, edges when drawn tempera- tures below 300 deg. Reduction vs. Temperature Another series draw tests was made order obtain more definite shov data maximum reductions possible various temperatures. Revisions were made the burner adjustments that higher temperatures could per obtained and closer control main- tained. For these tests, lighter gage sheet (0.040 in.) was used and the cent magnesium alloy AM-C57S-0 was in- tem cluded. The lighter gage sheet was used facilitate rapid and uniform deg. heating the blank the conduc- pera for mag- All blanks were allowed remain nesium sheets the die with the blankholder con- tacting the blank until the outer area double draw test reached the die temperature. This determine maximum time interval was sec. before the reductions. draw was started. using this method, the area the blank under ure the punch would lower tem- perature than the outer area the crem blank. This procedure was necessary order that the central portion mum strength withstand the impact eters the punch and the outer area would withstand the deformation during the draw without fracture. The die and ankholder were the same used ing the previous tests but punch with slightly greater diameter was used that the clearance between die and SECOND DRAW TOOL SET punch room temperature was 0.054 in. Die and punch radii were approxi- mately six and nine times the sheet thickness, respectively. series cups were drawn be- The cate tempe this sible presse The duced 1G. 2—These anc ata temperature deq. F, tom a nealed the proper inelude Alth one can Z y - 72—THE IRON AGE, May 10, 1945 ite ble ons nts uld age the in- was orm con- area This the this nder tem- the sary n of cient the and with and 0.054 proxi- sheet ese fail- from The fail- left tool rature while right tool 750 ° ° shells, produced from sheet, show the difference depth when tool temperatures were increased. Left shows reduction per cent with tool temperature deg. Center, re- duction was 40.5 per cent when the tool temperature was raised 450 deg. deg. tool tem- perature, reduction 63.6 per cent was ° ° ginning with the die and blankholder room temperature. The tempera- ture the draw tools was increased 250 deg. and then raised in- crements deg. until 800 deg. was reached which was the maxi- mum temperature which could ob- tained with this setup. Blank diam- eters were gradually increased each temperature interval until con- sistent failure occurred. The percent- age reduction blank diameter was then calculated using the follow- ing formula: Where original blank diameter. punch diameter. The curves shown Fig. indi- cate the maximum reduction obtained temperatures. One fact revealed this test was the high reductions pos- sible when using mechanical draw presses operating normal speeds. The cups shown Fig. were pro- duced room temperature, 450 deg. and 700 deg. F., respectively, from the AM-3S-0 sheet and show the in- crease depth cup with increase tool temperature. Tension tests made from specimens cut from side- walls and bottoms the deepest cup indicate that the sidewall properties are comparable those hard rolled sheet while the properties the bot- tom are similar those the an- nealed temper. Table summarizes the results these tests and the properties hard temper sheet are included for comparison. Although shells with depths one and one half times their diameter can produced single draw, many cases, necessary make two draws order obtain shells the desired depth. test was car- ried out using gage (0.064 in.) and sheet determine multiple draws could made produce deep drawn magnesium shells. the first draw- ing operation the blank diameter was reduced 50, per cent, depend- ing upon the diameter the blank used. The die for the second draw was designed reduce the diameter the shell the first draw per cent giving overall reduc- tion 75, 77.5 and per cent. Fig. shows sketch the tool setup for the test. The die, blankholder and punch for the first draw were the same those the first series tests but the punch was modified replacing the in. radius taper order shape the bottom the first draw cup the deg. entrance angle the second draw die. The second draw tools were also unhardened steel and main- tained temperature range 500 550 deg. means gas ring burners. toggle press was used for the second draw and was operated its normal speed strokes per min., giving punch velocity approximately that the 125-ton press. All blanks were heated tool temperature (500 550 deg. F.) electric air circu- lating conveyor type furnace. diffi- culty was experienced producing cups with and per cent reduc- tions from the AM-3S-0 and blanks. However, successful per reductions could made from either these alloys. Larger reduc- tions have been made single draw, but not with deg. bevelled punch. successful first draw cups per cent reduction were ° ° ° the deep draw- ala ing characteristics sheet. Temperatures were determined contact type py- rometer. 100 200 300 400 500 600 Tool temperature, Die and blank holder THE IRON AGE, May 10, 1945—73 i | | | | | 5—These shells were produced from AM-C52S-O sheet two draws. The reduction the 7.25-in. blank diameter (left) the first draw (left center) was per cent. The final draw (right center and right) reduced the first draw shell diameter per cent, produced from the blanks, and reductions lower than per cent were not attempted. Second Draw The second drawing operation con- sisted reducing the diameter the drawn shell per cent. The pro- cedure which gave the best results was let the shell sit the die for sec. with the blankholder contact with the shell before the draw was started. this method the AM-52S cups with and per cent drawn. Fig. shows the successful for total overall reduction 77.5 per cent. shells produced the per cent and per cent combination re- ductioris the AM-52S sheet which gave overall reduction blank diameter 77.5 per cent. Several first draw cups these two alloys were heated electric furnace 500 550 deg. and then placed the second draw tool determine this sec. interval could eliminated. Some the cups would draw depth ap- proximately in. before they would fracture while the cups would fracture without any draw tak- ing place. This condition was also reductions for sin- draws and rec- ommended tool tem- peratures duction conditions. Per cent reduction 100 200 300 400 500 600 Tool temperature, deg. Die and blank holder IRON AGE, May 10, 1945 encountered during the single draw tests when the blanks were heated. Generally that portion the blank which contacts the punch does not have sufficient strength withstand the initial impact the punch and the stress the drawing operation, the punch will pierce the blank with draw taking place. the center area the blank becomes heated, there corresponding loss strength and the metal can longer with- stand the load the punch and fail- ure will result. The 77.5 per cent maximum reduc- tion, shown these tests, not necessarily the absolute maximum the second draw reduction might increased per cent giving overall reduction blank diameter per cent. From our observa- tions, appears that the per cent reduction quite close the maxi- mum the second draw more diffi- cult than the first. The results these series draw- ing tests demonstrate that magnesium alloy sheet can deep drawn suc- cessfully single double draws mechanical presses operating normal speeds. the temperature range 450 550 deg. F., the has the best deep drawing properties the alloys tested. This temperature range practical working temperature for lubricant, tools, and presses. should derstood that the maximum reduc- (CONTINUED PAGE 142) eke of chi ma onl ori, cas chr den ing Was ting pha tem | | | | | | ( help | | trib | | | | | | | } | ° ° cont | | ~ & ted. ank not and and with nter ited, vith- fail- not neter erva- esium rature the awing This actical ricant, reduc- some reason seems that every time new process dis- covered the advantages and pos- sible applications are grossly ex- aggerated until fairly well along development. Precision casting exception this, being applicable the moment only relatively limited field, and most emphatically not The impetus given this process the current war has been enor- mous. The Air Corps, the opinion the writer, was the first the Armed Services become interested the process due its urgent need for large quantities turbosuper- charger blades. These must made heat resistant alloys that are dif- ficult, not impossible, forge and machine. This problem was presented the Austenal Laboratories, Inc., who not only succeeded casting the alloys originally specified General Elec- tric, but also proposed the use their alloy Vitallium. Prior the war, cer- tain the dental technicians, like Austenal, had been working with the casting nonferrous alloys, such Vitallium, which made cobalt, chromium and molybdenum, and had been able cast this material success- fully into precision shapes required dentistry. Since Vitallium has melt- ing point slightly over F., was obvious that the process was get- ting out the lower melting point phase and approaching steel casting temperatures. Vitallium proved highly satisfactory alloy for super- charger buckets and gave the process background experience which had been accumulated Austenal for sev- eral years preceding the war. tenal licensed several companies, helped them get into production quick- ly, and managed insure the ade- quate supply blades. difficult truly assess the value this con- tribution the war effort, but conservative, certain that has contributed greatly the production turbosuperchargers sufficient quantities, and time permit our planes “go upstairs” hurry, and that minor The process has gressed from the batch process used High Reproducibility Precision Casting Many steps the process lend rigorous scien- tific control. Future possibilities are appraised this article which abstract paper read the author before the foundry panel the Chicago War Production Conference, March 29. dentists and jewel- ers towards the continuous straight production technique which necessary large seale production. this respect, the industrial concern has least one great advantage over the dental tech- nicians that shrinkage may com- pensated for correction the pat- tern size, which is, course, not the case dental work where the cast pieces must reproduce exactly the dimensions the wax pattern. great deal credit due the companies who worked this process and cured its problems over the trying years. mention only few these companies, much the initial work was done General Electric co- operation with Austenal. mers has contributed greatly the required production, has Haynes- Stellite and many others. Suffice say, however, that the production going forward large scale and meeting our needs costs which immediately prior the war were considered practically impossible Ordnance Department Interested The Ordnance Department having greatly interested precision casting, but its requirements naturally differed from those the Air Corps. Ord- nance was interested primarily the casting different intricate parts from SAE and alloy steels which proved the most difficult all cast. The nonferrous alloys, including stainless austenitic steels, appear noncorrosive the molds employed and fairly easy cast, but the SAE steels including Chicago Ordnance District the high and low are highly corrosive and very difficult handle. little over year ago, was felt that the process had progressed far enough warrant comprehensive tests certain small intricate parts needed Ordnance. that time, appeared that the vendors were able, within reason, produce castings SAE 4140 steel and other similar al- loys tolerances the order 0.003 in. and having least “f” (machine) nish production basis. Although there had been previous test work conducted various parts for cannon breeches, the carbine was articles precision casting published the past year including the one the turbosuper- charger buckets, are now avail