The Iron Age 1945-11-01: Vol 156 Iss 18

$50 VAN DEVENTER President ord Editerial Directer more BAUR 9,594 Assistant Manager HAYES Advertising JOHNSON; has bill Service and Market th, for BAUR, Production Manager Promotion Manager can al- Executive Offices oresees Chestnut and Séth Sts. may 39, Pa., U.S.A, motors, and Advertising ectrical old use York York ady the East 42nd St. 100 East 42nd RAYMOND KAY Los Angeles 2420 Cheremoya Ave. and mis- the true Owned and Published ft, and CHILTON COMPANY seeks (Incorporated) MUSSELMAN, HILDRETH, President GEORGE GRIFFITHS TERHUNE Vice-President BAUR Vice-President FAHRENDORF Vice-President JULIAN CHASE Vice-President WILLIAM BARBER, JOHN BLAIR MOFFETT, Secretary BUZBY HARRY DUFFY THOMAS KANE CHARLES HEALE WILLIAM VALLAR, Asst. Treas, Chilton Editorial Board PAUL WOOTON Washington Representative Member, Audit Bureau Circulation and magnetic money, unveil- has will Member, Associated Business Papers new plant onc the Industrial Arts Index. Pub- every Thursday. Subscription Price containin Possessions, $8; Foreign, $15 per year. Single Copy, cents. the star AGE Vol. 156, No. Editorial Labor Trouble the ° ° Technical Articles Precision-Cast Copper-Base Alloys Flame-Cut Cinder Car Castings Replace Forgings. Invisible Ultraviolet Rays Proven Harmful Hidden-Arc Welding 13-Gage Steel. Fluoroscopy Light-Alloy Castings. Gas Carburizing (Part Extruded Magnesium for Safety Blocks Aging 75S Aluminum New Equipment ° ° ° Features News Front Assembly Line Washington West Coast Personals and Obituaries Dear Editor This Industrial Week News Industry ° News and Markets Machine Tool Developments 106 Nonferrous Market News and Prices 108-9 Iron and Steel Scrap News and Prices 110-11 Finished and Semifinished Steel Prices 112 Alloy Steel Prices 113 Fabricated Steel Products Prices 114 Warehouse Steel and Pig Iron Prices 115 Ferroalloy Prices 116 Comparison Prices Week and Year 117 Welding Society Elects New Officers 118 Russians Rehabilitate Damaged Blast Furnace 122 Aluminum Roofing Sheet Introduced 126 New Type Container 128 Re-employment Vets Steel Plants 130 Ayres Recommends Limit Wage Grants 132 Z-Metal Research Institute Formed 134 Light Gage Steel Structural Members 136 Wartime Advances Provide Good Magnesium 138 Brazil Foundry Highly Mechanized 142 Safety Programs Needed Industry 143 British Steel War Problems Discussed 145 Lead Time Estimates for Ordering 147 Contractors Delaying Termination Progress 149 ° ° Index Advertisers 245-6 November 1945 | | | | | | | | = Laboratory Assurance Quality Steel from Stock Maintenance Ryerson standards uniform high quality begins the labo- ratory nerve center the Ryerson quality control system. steels from our stocks are tested for tensile strength and duc- tility. Here double-check rigid performance specifications, determine hardenability data and prepare special report every heat alloy stock. copy this report sent along with every shipment. The assurance that your shipment steel from stock meets laboratory standards qual- ity can effect important savings for you. And many gain improved results from their heat treatment department through the use the’ Ryerson alloy reports. Whether you specify, CERTIFIED buy fabricate steel, our high quality standards protect your production and give you more for your steel dollar. Laboratory equipment for testing Ryerson steel includes: Brinell and Rockwell hardness machines, tensile testing and Erichsen ma- chines, hot acid etch apparatus for determin- ing structure, electric heat-treating furnaces and Jominy test equipment. These stand back the large, diversified inventories your nearby Ryerson plant. Call, wire write for high quality steel from stock. Joseph Ryerson Son, Inc., Steel-Service plants at: Chicago, Milwaukee, Detroit, St. Louis, Cincinnati, Cleveland, Pittsburgh, Phila- delphia, Buffalo, New York, Boston. ERSON STEELS STOCK: HOT COLD ROLLED, HEAT TREATED ALLOYS ALLEGHENY STAIN. LESS TOOL STEEL HOT COLD ROLLED CARBON STEEL BARS STRUCTURALS PLATES SHEETS TUBING PIPE INLAND 4-WAY FLOOR PLATE MACHINERY TOOLS, ETC. : ESTABLISHED 1855 VAN and BAUR and Editorial ° 9 ° JACK HIGHT WINTERS ALBIN JOHN ANTHONY BARMASEL Editorial SCHIEN SPEAR Editors LLOYD Pittsburgh Park Chicago Bidg. EUGENE HARDY ANSBORO Washington Press Bidg. Cleveland 1016 Guardian BRAMS 7318 Woodward OSGOOD WORTH HALE San Francisco 1355 Market St. Editorial DEAN Buffalo FRAZAR Boston HUGH SHARP RAYMOND KAY Los Angeles JOHN McCUNE Birmingham ROY EDMONDS JAMES DOUGLAS Labor Trouble the Barnyard PPARENTLY chickens have historically been credulous creatures, readily believing what they are told. Witness the ancient story Henny Penny and Chicken Little. You are still young enough remem- ber it, hope. any rate, somebody played prank upon them. Legend says that was fox who when nut fell from tree the henyard told Henny Penny and Chicken Little that the sky was falling. Whether they actually believed not not know. But know that they lost time spreading the story. Indeed, efficiently and eloquently did they spread the bad news that time all the barnyard was turmoil. And Henny Penny and Chicken Little became suddenly very important personages. Strangely enough perhaps, sidering chicken intellect, not strangely, they still retained their com- munity standing even after the catastrophe failed materialize. course, you could not pull the same thing twice, even with dumb chicks such inhabit barnyards. Foxy Loxy, the mischief maker, had think new one. toward fall, when the ground was getting frostbitten and the scratching was becoming harder, Foxy Loxy again approached Henny Penny and Chicken Little. Said he: “You folks work pretty long hours make ends meet seems me. Here you are scratching away from dawn twilight your henyard just make bare living. Don’t you know that the eight-hour day, five-day week here stay, least stay until can cut down some more? organize and stand for your rights, and recognition your leadership past occasions, appoint you shop stewards the henyard. Henny Penny and Chicken Little took their new responsibilities and the prominence they gave them quite seriously. The chicks the hen- heard the news the shorter work day and work week with rapt attention. “That will give four hours more day sleep and otherwise enjoy ourselves,” they said, “and two whole days week nothing but loaf and cackle.” the inhabitants the henyard formed organization known the Chickens International Order, and appointed six big roosters enforce the new rules. Thereafter, any hen rooster caught scratching except between the hours eight four Saturdays and Sun- days were fined six tail feathers for each offense. The only trouble with the new arrangement was that the worms wouldn’t cooperate, but stayed far underground ever. They did not recognize the fact that there was new era which the hens were have more worms for less work. after while the chickens began lose weight. The hens espe- cially did not mind first because from stylish stouts their figures were reduced debutante spring chicken models. But after while they became too scrawny and began wonder whether food was not preferable leisure. They asked the wise old owl the willow tree about but usual his reply went over their heads. said: “Your scale living determ- ined your productivity.” They took this saying woodchuck who had his feet the ground and put into barnyard English, wit: “As you scratch shall you eat.” q MUNZER A TOWNE ity ess na- ces our STREAMLINING THE “SW these days transition many manufacturers are going into the production radically new products, becoming familiar with new equipment, adapting old machines new uses and finding out how control processes that are different. They are the throes “swing-back” from wartime operation peace- time manufacturing. Inland metallurgists are familiar figures many these plants, where for years they have been apply- ing their expert knowledge putting steel work for others. Today, Inland metallurgists are continuing that valuable work. Their technical and practical experi- G-BA ence the selection steel, latest fabrication methods, and speeding output, are helping manu- facturers produce many kinds newer products. you have problem the use steel, call us. member our metallurgical staff will glad call and work closely with you. Inland Steel Company, Dearborn St., Chicago Sales Offices: Cincinnati, Detroit, Indianapolis, Kansas City, Milwaukee, New York, St. Louis, St. Paul. Principal Products: Bars Structurals Plates Sheets Strip Tin Plate Floor Plate Piling Reinforcing Bars Rails Track Accessories | 4 cr. | ha: pos h | News Front Bethlehem launched long range expansion program for its West Coast facilities with the installation the fourth openhearth its Los Angeles Later, Bethlehem expects spend $200,000 the Seattle nut and bolt plant, should permit supply the needs the entire western market. .First shipments the new Nash are being made. First production limited sedans the low price "600" and medium price Ambassador lines. Nash annual production rate 150,000 units January, 250,000 June. Canada's dead and missing during the war was 41,000 (exclusive air crews the RAF) which pct higher than the U.S. total 294,419 when adjusted basis. War expenditures totaled $18.2 billion compared $280.6 June for the S., the former being pct lower when adjusted antioxidant and rust preventive developed the USSR during the for removing rust from captured enemy materiel, now coming into use for the protection steel particularly for the preservation oil well casings. During the height the coal strike, WPB officials were worried about its steel production that they seriously considered the installation the system emergency measure. The move died when the coal ended. trading seems assured the bright new world, the British Empire industrialists now meeting London hold sway. the obvious benefits the present system, promoting trade within the the possible expense other international trade, are primary African consumer market possibilities are being encouraged England, partly the use some the $480,000,000 voted spent the next ten for the development the colonies. Merging the seven central African administrative units under British into one governmental unit also being studied for the same reason. models civil aircraft for Britain will continue financed government subsidy, due the great increase cost the prototypes during the war. The view held that operating airline hopeful airframe manufacturer could expected bear the full costs and risks. Pressure being applied the British Ministry Aircraft Production release the controls aircraft production. Under present restrictions the inistry dictates absolutely all production matters, just did throughout the war. Night carrier flight operations the fleet were halted immediately the end hostilities due very high accident rate. The Navy will continue ask for appropriations for night fighter force. Some dissatisfaction being felt with the new government England due criticism the handling housing construction. being voiced both the Conservative party and extreme Precision casting offers two important advantages leading castings high hardness and strength. These are control investment temperature and the — possibility quenching the castings under controlled conditions. varying investment temperature and quenching conditions, wide range netallurgical properties are obtainable especially those alloys that undergo phase changes. Use the fluoroscope with rotational scanning detect flaws light castings shows surprisingly large number medium and larger defects that seen radiographically. This OPRD investigation also resulted improved protective window. ubstituting Lucite cell filled with nearly saturated aqueous solution lead erchlorate, the disadvantages lead glass window that turns brown when rays are eliminated. Oct ir aul, lates > INCE nonferrous precision cast- ings have many potential appli- cations ordnance equipment, the Frankford Arsenal laboratory has undertaken metallurgical study the properties some representative nonferrous alloys cast this means. The substitution, some instances, fairly simple, being merely the re- placement sand casting pre- cision casting for the purpose re- ducing eliminating machining oper- ations. most instances, however, foreseen that precision casting will replace part machined from bar stock, sheet other wrought metal stock. The properties the precision casting must then equivalent that the wrought metal replaced. many cases, half hard and full- hard stock specified order ob- tain the benefit increased hardness and strength. obtain equivalent properties copper-base precision casting such high-strength alloys would re- quired yellow brass, aluminum bronze, manganese bronze and lium copper. From these considera- tions, evident that, for intelligent utilization precision castings, fund data necessary the prop- IRON AGE, November 1945 Precision Cast Copper Base Alloys ° ° and ROSENTHAL Metallurgists, Frankford Arsenal, Ordnance Laboratory, Philadelphia Data are being accumulated the metallurgical properties nonferrous precision castings the Frankford Arsenal Representative alloys from the zinc-base, aluminum-base and mag- nesium-base alloys, well the copper-base alloys, are already being studied. This report presents some the data collected four copper-base alloys: leaded red brass leaded yellow the first part this two-part article, the procedures and tech- erties which may specified for pre- cision-cast alloys. The process precision casting can divided into five phases: (1) Casting wax patterns mold. Fastening one more wax patterns into assembly provided with wax sprues and gates. (3) Pouring investment around the wax assembly which hardens into ceramic refractory. (4) Melting and burning out the wax from the investment. (5) Casting the desired alloy into the cavity previously occupied the wax. Precision casting offers considerable latitude casting conditions unob- tainable with other casting techniques. One the most important these the control investment tempera- ture. With most the other types casting only the extremes are avail- able: chill conditions with die and permanent-mold casting slow cool- ing with sand casting. Another important point associated with precision casting that the hot plaster-type investment decrepitates rapidly when plunged into water. This permits the possibility quench- ing the castings under controlled con- ditions. brass (60-40), high-strength manganese bronze and silicon brass. niques used casting the test specimens are fully described. varying the investment tempera- ture and the quenching conditions, wide range metallurgical proper- ties obtainable. course, this especially true those alloys which undergo phase changes. Casting Technique There natural division between precision casting nonferrous and ferrous alloys. The investments for nonferrous alloys consist silica and plaster paris, the latter acting binder. Ferrous alloys react with the plaster, thus necessitating other types binding material. The more refractory binding materials require relatively complex procedure during the investment stage the process. its present stage development, precision castings are restricted small sizes and consequently involve the handling small melts. Although this fact does not impose too formid- able barrier the handling non- ferrous melts, small ferrous melts re- quire special pains prevent prema- ture freezing. These conditions have influenced the technique which the metal cast into the ceramic mold. The trend for ferrous alloys cast with the least possible delay meth- ods akin static casting with without the addition air pressure - \ e | us | py | er | mM: RIGHT injection machine showing mold posi- tion and pressure gage. BELOW 3—This arrangement wax patterns rub- ber sprue base gave unsound castings when used with the 60-40 leaded yellow brass. This design be- lieved give rise too much turbulence when the 60-40 alloy enters the mold, thus causing entrapment help force the metal into the mold BELOW The trend for nonferrous alloys 5—Tree design used for use centrifugal force for injecting the manganese bronze castings. metal into the mold. The small riser-like projection for velopment from rather crude more others, the changes were required the varying characteristics the quire alloys studied. ABOVE 4—Tree design adopted for Methods and Materials the 60-40 ment, Specimens: Because its conveni- ent size, the 0.252-in. diani, 1-in. gage volve length, threaded-end tensile specimen was adopted for this work. lead- based the actual cross-section. rmid- base alloy mold served for casting the The mold which the wax patterns non- wax patterns. The lead-base alloy were cast was made the split half machined specimen the primary the machined model was covered have model. This resulted the final cast- plaster (Rapidstone, Kerr Dental the ings being slightly than the Mfg. Co., Detroit). alloy consist- mold. primary model because the shrink- ing 59.2 pct lead, 13.6 pct tin and cast age the wax and the metal casting. 27.2 pct bismuth was then cast meth- However, the gage diameters the against the exposed half. The plaster cast specimens were measured before was removed, parting testing that the tensile values were lamp black applied the mold sur- surface dirt and oxides. face, and the second half the mold cast against this surface. The com- pleted mold with drilled sprue and guide pins shown fig. Waz Injection: Wax patterns were cast injecting molten wax into the mold cavity. formulation consisting THE IRON AGE, November Counterweights crucible arm representation the centrifugal casting machine. The molten metal poured into crucible which designed hold the metal until the apparatus starts spinning whereupon the metal acted upon centrifugal force accelerating outward direction and into the flask. equal parts rosin, ceresin, and carnauba wax was maintained 10° above its melting point the injection machine. The machine was equipped with electrical heating ele- ments thermostatically controlled. shown fig. with mold posi- tion. The apparatus was especially de- signed inject the wax air pres- sure into the bottom the mold with definite pressure-time cycle. the beginning the cycle, the wax in- jected low pressure order allow time for the air driven out the mold, thereby preventing entrapment. The pressure then rises psi and maintained until solidifica- tion has been completed. After the pressure relieved, the mold re- moved from the machine, further cooled air blast, and the wax pattern removed. Patterns were in- spected for defects and the patterns were then ready for the next opera- tion treeing. Treeing: convenient number wax patterns, usually eight, were mounted into assemblies called trees. small, pencil-type soldering iron was used melt the wax wherever junction was desired. Various ar- rangements which the wax tensile specimen patterns were mounted the rubber sprue base are shown figs. and The reasons for the changes arrangement will ex- plained later. Investment: Into the lip the rub- ber sprue base set steel tube known flask. The flask in. long, in. diam, and made low-carbon gage welded tubing. The investment then ready poured around the wax assembly con- tained the rubber sprue base and flask. The investment mixture and gypsum acting binder. Cer- tain small additions are made for con- trolling the setting time. This invest- TABLE Chemical the Casting Alloys Element Analysis Silicon Brass Manganese Bronze Spectrographic Analysis Plus named elements less than ASTM spec. B145-44T comp. ASTM spec. B146-44T comp. ASTM proposed spec. comp. 12C ASTM spec. B147-44T comp. 48—THE IRON: AGE, November 1945 ment was also supplied the Kerr Co. Two parts the investment are mixed with one part water weight. After thorough mixing, the creamy mixture placed under bell jar and the air rapidly evacuated vacuum pump. this means, the air churned into the investment elimi- nated. The tree immersed clean the wax and leave thin liquid film. The vacuumed in- vestment now poured into the flask, and because the alcohol dip, wets the wax without difficulty. second vacuum treatment now removes the last traces air still present assure perfect contact between invest- ment and wax, uninterrupted clinging air bubbles. from the bell jar, the flask put aside for hour order give the in- vestment opportunity set. Burn Out: soon the invest- ment has set, the rubber sprue base stripped from the flask which placed oven, The oven main- temperature the wax liquefies and most runs out the flask al- though part absorbed into the in- this stage, the flask transferred the burn-out furnace where the temperature slowly raised and held this temperature for hr. The fur- nace then permitted cool with the flasks the various temperatures being studied from 400° 1200° The burn out accomplishes two things. First, the wax completely removed and second, the gypsum calcined. Both these processes con- tribute toward increase the permeability the This artificial vents were provided for purging the air during the casting the metal. Casting: schematic representa- tion the casting machine shown fig. The molten metal poured into crucible which designed hold the metal until the apparatus starts spinning whereupon the metal acted upon centrifugal force accelerating outward direction and into the flask. Both gas and induction heating methods were used for melting. The gas-fired melting and preheating fur- nace shown schematically fig. was used only for the 85-5-5-5 alloy and the induction heating was used for the The metal was meited under borax flux and its temperature measured chromel- alumel thermocouple protected silica tube. Both the melting and casting | Comp., Spec. Comp., Spec. Comp., Comp., Spec. 6.12 4-6 Rem. Rem. Rem. 5-16 Rem. Rem. 0.04 0.30 0.22 0.75 max 0.24 2.5 max 2.46 0.03° 1.5 max 2.23 2.5-5.0 are the bell air eave in- lask, wets the noval aside ivest- base ich main- this and al- in- ask slowly this fur- with atures 00° two pletely con- the This ting esenta- shown poured metal force heating The fur- fig. alloy was and its ble are clay-graphite composition. The melting crucible has pour arrangement; the casting cruci- ble patented design (Thomas Dee Co.). With the induction heating ar- rangement, the melting crucible was heated coil. After the metal was melted, the crucible was lifted out the coil and placed fire brick. While the metal temperature was be- ing measured, the Dee casting crucible was placed the coil and preheated. When the metal reached the casting temperature, the Dee crucible and the flask were removed from their respec- tive furnaces and placed the cast- ing machine. The metal was then poured into the Dee crucible and the motor started. The speed was in- creased until rate 250 rpm 350 rpm was reached and the apparatus was then allowed spin constant speed while the metal solidified the flask. about min the machine came rest. The flask was then re- moved from the machine and either water quenched slow cooled de- sired. Phosphor-copper was used for de- oxidizing the 85-5-5-5 alloy min be- fore casting. Approximately 0.01 pct phosphorus was added and stirred attempt was made make additions since little flaring was encountered with the tempera- tures used. Commercial ingot alloy was used Flame-Cut Cinder Car cutting machine, midwestern steel plant recently saved more than pet the cost new piece equipment. This plant needed re- placement for cinder car rack, hold the cinder car while be- ing tipped discharge its molten slag. The original rack had been cast. avoid the high cost and lengthy delay that would involved mak- ing pattern and mold for the single replacement, was decided flame- cut the part from 5-in. thick steel slab with Oxweld shape-cutting machine. Since only limited number the racks were cut, templet for guiding the cutting machine was saw- out composition board in- stead using the standard aluminum templet strip. This faster, cheaper method was entirely satisfactory for this application because the templet was used only few times. Flame- cutting was sufficiently accurate leads 7—Diagram the melting and preheating furnace used for the 85-5-5-5 alloy. for the metal charge. analysis the ingots gave the results shown table Test Conditions The test data are presented mainly the form graphs. Averages have been plotted for tensile strength, elongation, hardness These averages cover one three separate casts made under identical conditions. Tensile tests were made hy- draulic testing machine. gage length in. was prick punched the specimens obtain the elongation figures. Specimens breaking outside the gage length and those show- ing inclusions the fracture were from the calculations. Unbroken tensile specimens were cut for the density and hardness that machining the part was necessary. further saving real- ized this steel plant since Entrance for air gas measurement and supply specimens for the metallographic studies. For density determination, speci- men removed from the gage length was used. The surfaces were polished eliminate any possible error from bubbles lodging small crevices dur- ing the weighing water. Values density were corrected for Hardness readings were taken milled threaded-end the tensile specimen. The end the specimen selected was that closest the sprue the original casting arrangement. Metallographic sections were trans- verse faces cut from the center the gage length. Ed. Note: Next week, the properties precision-cast leaded red brass, leaded yellow brass, silicon brass and ganese bronze are Rack now unnecessary stock these racks replacements wait for delivery when needed. 1G. Oxweld cutting machine and the completed rack. Notice that pair racks are made with each single cut. Gear blanks have been cut from part the slab, using the same machine. THE IRON AGE, November crucible rucible — BROMHEAD and PIPER Materials Engineer and Chief Process Engineer, Respectively, Northrop Aircraft, Inc. unreliable from quality standpoint, alloy steel cast- ings are made aircraft quality standards and prove highly efficient structural members vir- tue their high weight- strength value. themselves new, having been used for nearly years such applications the rail- road and transportation industry, machine tools, and for valves and pipe fittings, their use aircraft construc- tion marked radical change de- sign thinking. During the first world war some alloy steel castings were tried out, but the quality was poor that they were rejected. Being con- that the desirable qualities alloy steel castings offered suitable structural material for use aircraft design sufficiently high quality and close finishing tolerances could ob- tained, Northrop mented extensively the use cast- ings their own aircraft designs. The quality required prere- quisite for aircraft use designated the Air Corps design handbook, such castings being known Aircraft Quality castings. Close finishing toler- ances are necessary avoid expen- sive machining operations and for minimum weight portions cast- ings requiring finishing. was considered that such castings might replace steel forgings and other high- strength alloy castings such beryl- lium copper and aluminum bronze which were difficult procure during the early days the war. steel castings aircraft quality are lower cost than steel forgings, since patterns are appre- ciably less expensive than forging dies, especially when only small quan- steel castings are not TABLE CHEMICAL COMPOSITION Silicon Yield Heat Tensile Tensile No. Strength, Psi Strength, Psi 132,990 Sanoahwn- 50—THE IRON AGE, November 1945 Phos- phorus Elongation, Pet Molyb- Chromium denum 1.04 1.02 1.02 0.90 Sulphur MECHANICAL PROPERTIES Reduction Area, Pct oaocaqawa- tities parts are involved, and the raw material itself considerably cheaper than copper alloys such aluminum bronze beryllium copper. Furthermore, intricate shapes can cast much more readily than forged, and there are objectional direc- tional properties such occur forgings. Savings can effected machining time since possible cast close contours approaching the finished dimensions the part, and such castings can easily welded other parts fabricated from wrought steel, such engine mounts made welded tubing. The high strength- weight ratio alloy steel castings compared with other alloys makes them lighter than corresponding cast- ings any other alloy having the same strength, and reduction area, impact, creep, and ultimate strength values are much higher than other alloys. The use steel castings aircraft structural parts permitted the Army Air Forces under restric- tions that such parts must static tested unless stress analysis shows that they have margin safety 900 pet. Castings having margin safety 900 pct are classified Class castings, all others are Class Class casting can accept- the quality does not conform the Army Air Forces aircraft quality castings standards, outline which given below. Defects generally causing localized stress concentration are causes for rejection unless they can removed finishing within tolerances, viz: (1) Cracks (2) Shrinkage cavities Cold shuts (4) Misruns (5) Discontinuities listed fol- lows which are alined cause stress concentration. a—Gas porosity b—Microshrinkage c—Dross oxide inclusions d—Sand e—Blow holes f—Segregation g—Mottling With these requirements stand- ards Northrop obtained test lots castings from newly established foundry where special casting tech- nique was used attain aircraft quality castings. These were required have maximum machining allow- ance 0.125 in., and some surfaces this was held 0.063 in. max. minimum draft was specified ver- tical surfaces, and specially proc- essed type mold was employed. The sand mix was carefully controlled produce the finest finish closely ap- a p a n n | ° ° m lis Man- 0.36 0.93 0.64 0.037 0.024 0.63 0.75 0.61 0.034 0.024 0.38 0.78 0.62 0.040 0.025 0.64 0.38 0.80 0.69 0.034 0.025 0.39 0.94 0.71 0.043 0.028 0.75 0.32 0.67 0.63 0.034 0.020 0.30 0.89 0.60 0.039 0.022 0.64 0.31 0.65 0.62 0.035 0.022 0.35 0.77 0.67 0.032 0.019 len 116,670 15.5 36.0 294 132,000 108 500 17.5 37.0 294 145,410 123,470 15.0 33.0 301 sel 132,500 18.5 30.0 268 78,000 22.5 50.5 215 127,000 19.5 43.0 253 105,000 78,500 22.5 52.0 235 110,000 85,000 21.5 41.0 235 cept- does orces ards, for 10ved fol- cause stand- ots tech- ircraft quired allow- ax. ver- proc- The ely ap- proaching machined surface pos- sible. Table list nine typical heats and shows chemical compositions and mechanical properties. Northrop Co. specification was prepared control the chemical com- position castings classes 4B3 and 4C3 the Federal Specification QQ-S-681 for use when castings were welded wrought steel parts. This restricts the composition maxi- mum percentages carbon 0.25, molybdenum 0.25, copper 0.5, and nickel 0.5. With these limits placed the alloying elements perfect welds can made. Test castings from new patterns are subjected close di- mensional inspection, and magnetic inspection made order detect surface cracks and other imperfec- tions. The Army Air Forces aircraft quality castings standards outlined this article have been supplemented Northrop’s radiographic and inspection procedure, the purpose which provide prac- tical and positive method handling the and fluoroscopic in- spection all production castings. This procedure provides (1) ap- proval ray laboratories Northrop Aircraft, Inc., (2) that the laboratory supplied with stress marked prints the cast part for the determination the required number radiographic views taken and for the laboratory technique approval Northrop, and (3) the setting radiographic standards for quality control. This procedure has been ap- proved the AAF inspection section and has become the basis for revisions AAF radiographic standards. connection with this inspection standard nomenclature lished for use identifying images casting irregularities appearing radiographs and fluoroscopic screens, Further research still needed casting technique and the effects XPERIMENTS with baby chicks reveal that exposure eyes invisible ultraviolet light ranging from 300 365 millimicrons wave length, range previously considered harmless some authorities, delays dark adaption and impairs visible funetions even when the eyes them- selves show obvious injury. These findings have been revealed Dr. Ernst Wolf the Harvard Biological Laboratories result research RIGHT strength-weight ratios cast alloys and 24ST aluminum alloy (wrought) for comparison. BELOW bers. Note the high quality the sur- face finish. shrinkage the internal structure the casting order that the de- signer may predict advance the effect size, shape, wall thickness, and dimensional requirements the facility with which castings air- craft quality may made. The ex- perience gained thus far, however, both foundry and user, should open the way for increased use high- quality alloy steel castings other industries. Weight savings will sponsored American Optical Co., Southbridge, Mass. Because human eyes could. not used view the potential danger, baby chicks were selected for testing, the visual characteristics their eyes approximate closely those human beings, and also because chicks obligingly kept their eyes wide open during exposure ultraviolet. the past has been recognized that excessive ultraviolet encountered welding operations, the arctic, tensile strength Magnesium -Dow Aluminum allo taken into consideration, and foundry technique improved with castings being made closer toler- ances, already possible with very small cast parts, the use alloy steel castings will broadened many uses where they are not now consid- ered practical. The quality consis- tency such castings for the past shows scrappage 9.07 pct, rework 12.23 pet, and 78.7 pct re- ceived without rework. Invisible Ultraviolet Rays Proven Harmful the sea shore may damage eyes, but some authorities had assumed that the rays below 300 millimi- crons length were excluded filter lenses the possibility eye injuries would eliminated. Dr. Wolf’s ex- periments, however, indicate that ra- diations below 365 millimicrons defi- nitely impaired visual functions, and the conclusion drawn that such rays are dangerous and should ex- cluded from human eyes prevent impairment vision. THE IRON AGE, November er. ed, the ion, and >» raft tric- the expected develop- ments the welding field postwar years the extended use automatic equipment. One recent job which this new welding advancement helped speed was the manufacture thousands watertight metal containers for shipping and storing bombs. The work was done the Phillips Mine Mill Supply Co., Pittsburgh. This rather unusual box design. All seams are flanged outward 45° provide stiffening ribs 1-in. high. The box made 13-gage steel in., with tolerance plus 1/16 in. minus 0.0 in. all inside dimensions, which permits practically distor- tion. The top bolted with mas- tic gasket and all corners adjacent the top are reinforced with small gus- 52—THE IRON AGE, November 1945 set plates which are continuously welded the manual The test which these boxes must withstand air pressure test with the box completely submerged and they must withstand the same water tightness test after being dropped each corner fully loaded (500 load) steel deck plate. Several methods manufacture were considered, such automatical- continuously welding the edges and inside corners, welding through one flanged rib into the other with either one two passes, one through IG. Cross- sectional view welded joint used the construction the bomb box. CABLE Welding Engineer, Lincoln Electric Co., Cleveland weld and one edge weld, closely spaced spot welds and the edge weld. Since the ribs were spotted the assembly jig, this last process was obviously the fastest and most eco- nomical and, upon finding this con- struction adequate under test, was adopted. The sheets were sheared, punched required and corners notched second operation, and edges flanged 45° forming third. Handles were spot welded the sides. The sides and bottom were then assembled accurate jigs maintain inside dimensions and the flanged edges spot welded every in. The edges were Since maintenance the inside di- mensions such close tolerance imperative, obvious that varia- tions sheets detracted from the fit- for the automatic edge weld. some cases edges were out line vertically more than the thickness one sheet. Some seams were crimped the spot welding were open the edge almost the thickness sheet. Despite these conditions, excel- lent welds were generally obtained high speed. The sides and bottom assembly placed simple jig positioned un- der the beam which the welding head, control box, wire reel and flux hopper travel. The jig designed provide V-shaped flux dam retain the flux deposited over the seam. This arrangement can seen the general view the installation, figs. and guide wheel supported from a ~ ; ate yhe \ view ahe fut sho . wi m hi; tir tre col Se] ° ° ° RIGHT 2—Close-up view automatic weld- ing unit producing edge weld box structure. Note guide wheel supported from electrode contact shoe. ° ° ° closely ted fig. which shows the welding unit operation. The head allowed hinge freely within the limits around its regular hinge point that can was follow the guide wheel along the seam. The flux fed the side unched the electrode order bring the flanged the are. exceptionally dense, uniform The bead with ample penetration the embled joint pointed out fig. which inside was sketched from actual cross-sec- tions through completed specimens. the original setup the 62-in. edge weld joining the side and bottom was made (120 in. per min) with side di- 400 amp the arc. Higher speeds could run but was found that poor fitups had the fit- tendency cause pin holes the veld. higher speeds. line During the first few days this operation, pin hole trouble developed crimped after the flux had been run through open the vacuum cleaner three four times. The cause this was found excel- minute slivers wood picked ained through handling the flux wooden kegs and boxes. This was im- mbly mediately discontinued the un- trouble alleviated, though was not welding completely stopped until additional and separator tank was placed front igned the vacuum pick-up unit that retain the seen from 13-Gage Steel dirt and fines were effectively sepa- rated. Pickled but sheets were specified and used, but shortly after starting the work batch sheets was received that had been oiled mistake. effort overcome re- sultant holes, both current and speed were increased with the result that even better seams were produced the rate 62-in. seam sec (128% in. per min) with 500 amp interesting aspect this pro- duction bomb containers was the competition between the three shifts with the result that each shift tried outdo the other production. one day the first shift welded 172 boxes, the second shift welded 186 boxes, and the third shift welded 169 boxes, total 527 boxes, 1052 seams hr. This the rate seam every min and sec all day long, allowing time out. Consider that the operator and his helper had take the box from standing posi- tion and place the jig, make the weld and pick the excess flux, re- tract the flux dams and turn the box across the positioner the other seam, replace the flux dams, weld the second seam and pick the flux, again retract the flux dams, take the box off the fixture and stand end away. This represents splendid example manpower per- formance well machine per- formance. The welding equipment permitted the use one grade and type flux together with one analysis elec- trode and the same procedures for wide range steel analyses. Thus, special joint preparations, changing flux, wire analysis and welding procedures are eliminated, which tremendous importance the use automatic welding. Furthermore, the equipment handled in. 7/32 in. electrode without changing drive rolls, wire contact control, the latter being extremely simple, giving the op- erator quick, easy independent control over voltage, current and speed when changing from one job another. THE IRON AGE, November 1945—53 q | i. detection castings has been popularly recognized that fluor- oscopy runs poor second radi- ography. Accordingly very large vol- umes radiographic film, especially for the examination light alloy air- craft castings, have been used the last few years. The investigations here described were undertaken California Institute Technology for the Office Production Research and Development the War Produc- tion Board. The purpose this in- vestigation was determine more precisely the limitations fluoro- scopy, the possibilities improving fluoroscopy, the possibilities sub- stituting fluoroscopic examination for radiographic methods certain types inspection, and the possibilities extending the scope fluoroscopic in- spection methods parts which can- not economically radiographed. may pointed out that these investi- gations have shown that some the popular notions fluoroscopic per- formance and limitations are not en- tirely correct. ultimate sensitivity flaw For another article fluoroscopy light metals, see issue April 20, 1944. 54—THE IRON AGE, November 1945 Fic. Portable fluoroscopic unit. Ex- terior view showing loading position and inspection room. 4 a When this investigation was started there were industrial fluoroscopes use and for sale, but they were not readily available for delivery that time. For preliminary tests fluoro- unit similar some the commercial types was constructed us- ing Westinghouse 140 kvp industrial ray unit basis. The conveyor and viewing arrangement was made somewhat similar that used General Electric commercial model. Figs. and show the arrangement used. Conveyor trays endless chain carried specimens through lead-lined tunnel over the ray tube. The observer dark room examined the screen looking downwards horizontal screen over the specimens. The conveyor trays could moved speed variable from stop fpm the operator’s choice. The protec- tive window was the customary 1-in. thick packet lead glass, treated reduce surface reflections. The ray tube with 2.4-mm focal spot was operated voltage 140 kvp and with tube current ma. the preliminary tests the tube was placed that the focal spot was about in. from the tray bottoms. This equipment was installed tem- Fluoroscopy porarily few foundries where large number castings various types were examined. The following experiences were quickly attained: (1) All observers all types and thicknesses castings pre- ferred operate the equipment the highest thereby attaining highest screen brightness. (2) desirable have the viewing window adjustable that may moved toward the screen get “closer look” defect images from small castings. (3) Extreme dark adaptation the observer leads uncomfort- able “glare effect” from unmasked areas the field. Perfect masking impractical except very un- usual circumstances. Better results are attained with partial dark adap- tation the illumination level the screen. proper level illumi- nation the dark room more comfortable than none all. (4) desirable have only one casting the field view time. several castings are put tray simultaneously, the reliability visual scanning reduced. (5) Continuous motion the screen image across the field view reduces tendency toward form eye fatigue which the observer sees “spots.” The apparent motion produced observing stationary image with manually moved low power magnifying glass also re- duces the tendency see spots. (6) account the large num- ber uncontrollable variables in- volved seemed almost impossible get any fairly reproducible and quantitative measure fluoroscopic performance from this preliminary investigation. After these preliminary experiences seemed that the only way get quantitative statement fluoroscopic performance was examine series artificially simulated defects known sizes under carefully controlled laboratory conditions. The artificial specimens used these tests consisted sandwiches two flat blocks { \ a e 0 in Ww Research Engineer and Associate Professor Mechanical Engineering, Respectively, California Institute Technology ° 3-SO aluminum alloy, each block This investigation indicates that the fluoroscope using rota- arious in. long, in. wide, and in. thick. The total thickness each scanning shows surprisingly large number medium and specimen was in., which any de- defects that are not detected radiographically. Also de- types sired additional thickness alumi- num sheet could added. Artificial scribed superior type protective window take the place ent defects, the form spherical cavi- the conventional lead glass window which discolors. ties, long cylindrical cavities, and flat washer-shaped cavities, were intro- duced the interface between the two blocks each sandwich, shown percentage the total number re- age thickness cavity reliably de- the fig. The spherical and long cylin- ported defects (not including blanks) tectable function area the that drical cavities were formed press- which were reported correctly. cavity, thickness the specimen, screen ing spherical steel shot segments These tests were made with many rate thickness transition the defect steel wire known dimensions be- observers under various controlled boundary and other factors not tween the two blocks. The flash was conditions, such total thickness well defined. Spherical cavities tion filed off. The pressing and filing were specimen, speed tray motion, dis- much harder pick than repeated until only the desired cavity tance ray tube from tray bot- long cylindrical cavities same masked remained. The washer-like cavities toms, distance screen from speci- diameter. The were produced use end mill. mens, etc. Most observers had cavities turn are much harder un- The proper alignment the two experience. Three four, detect than washer-like cavity results blocks the sandwich was assured however, including experienced thickness equal the cylindrical adap- two brass pins opposite corners. film reader, became experienced diameter. Drilled holes both di- evel The diameters the spheres and oscopic observers during the course ameter and length equal the di- illumi- wire, and the thicknesses the this investigation. The more sig- ameter spherical cavity with more washer-like cavities used these findings the result these which they are compared are more specimens were: 0.063 in., 0.050 in., are follows: visible than the sphere when the only 0.045 in., 0.040 in., 0.035 in., 0.030 in., (1) entirely improper as- axes the drilled holes are the 0.025 in., 0.020 in., 0.015 in., 0.010 in., sign blanket “percentage sensi- direction the ray beam but are put and 0.005 in. Four locations the tivity” fluoroscopy. The percent- not more visible when the axes are face the block were used that observers would not get accustomed 2—Arrangement the ray tube head lead-lined box beneath the con- form each run. order for the observer score correctly had report not motion only the nature the defect but its position the block (such corner, ved low center, edge, etc.). Results were tabulated for each test ots. run form shown fig. where num- the columns the type and bles in- location the defect, and each suc- possible ceeding row indicates successively ible and smaller thicknesses defect. Correct roscopic identifications are shown iminary charts white squares, incorrect identifications black squares, and get squares. scoring method was used roscopic which relative figure merit series was derived the product sensi- tivity score and reliability factor. The sensitivity score was determined artificial the percentage the total number onsisted defects identified correctly. The re- locks liability factor was determined the THE IRON AGE, November | ° ° ° | cylindrical defect Shor horizontal line short side Long horizontal line center 3—Test specimens with artificial defects. ong horizontal line long side hort side spherical efect enter defect ong side spherical defect orner spherical defect reported Correctly Defects reported incorrectly Defects not reported 56—THE IRON AGE, November 1945 SS 4—Forms used for tabulation results observer tests. appreciably inclined that direc- tion. However, very small drilled holes are not more visible than the spherical cavity even when their axes are the direction the beam. This understandable assumed that sharp boundary the image makes more visible, but that very small images cannot have relatively sharp boundary account the grain the screen. The percentage sensitivity be- comes smaller, i.e. improved, with increased total thickness the aluminum the absolute sensitivity decreases with thickness such way that the percentage sensitivity improves almost, but not quite, proportion thickness. (2) Despite the geometrical dis- tortion and penumbra unsharpness due the size the focal spot the tube, spectacular increase test score obtained putting the focal spot about in. from the tray bottoms instead in. these tests the screen was in. above the tray bottoms that the range focal spot-screen distance was from spot-screen distance over the range ‘ F ne Blank Center Short side washer Center washer Long side washer Corner washer center vertical line ce { Aff, | ca oO w wo oO w wo direc- rilled the their the ndary isible, annot ndary the with in. itivity uch itivity ite, rpness pot ase the tray these the ige from range the screen brightness factor sereen brightness only slight dark adaptation required for com- fortable viewing. There ap- preciable glare effect masked areas, thereby making in- tricate masking methods unneces- sary. The effect “seeing spots” also seems disappear unless the observer strains his imagination the limit becomes appreciably fatigued. Fig. shows typical comparison test charts for long and short distances. 8.3. With increased (3) Under any set viewing con- ditions takes the observer much not really sees