The Iron Age 1942-04-09: Vol 149 Iss 15

| 1942 7 7 7 New BALL BEARINGS FOR VICTORY Specify bearings American standard and tolerances wherever possible! They may made faster. “Specials” require extra tooling; waste precious time that could used finish many standard bearings. And complicate servicing machines the field! While the design stage, specify bear- ings that may had from several sources. Consult bearing engineer. APR 1942 Departure Division General Motors Corp., Bristol, Connecticut; Detroit, Chicago, Washington, San Francisco large Eastern Company first and has increased its purchases since then total more than 50. This evidence satisfaction with Clevelands confirmed letter from one its Engineering “Our Cleveland Worm Gear Drives have given excellent account themselves. the more pur- chased, are driven H.P. motors and have operated day and night. “We certainly will buy more your Drives install additional machines?’ Install Clevelands your new equip- ment and help insure trouble-free operation and maximum output—8 hours day, 24. The Cleveland Worm Gear Company, 3252 East 80th Street, Cleveland, Ohio. Affiliate: The Farval Corporation, Cleveland, Manufacturers Centralized Systems Lubrication Canada: PEACOCK BROTHERS LIMITED THE IRON AGE, published every Thursday the CHILTON CO. (INC.). Entered second class matter November 1932, the Post Office Philadelphia under act March 1879. yearly North America and South America, Foreign $15. Vol. 149, No. 15. APRIL 1942 This Week in... VOL. 149, NO. THE President and Editor Vice-President and General Manager Monaging Editor, LIPPERT Editorial Associate Editors JAMES Art Editor, WINTERS Technical Articles | 7 Resident District Editors Precision Aluminum Castings San Francisco Steel Mill Applications Rectifiers Buffalo Cincinnati Chemical Analysis X-ray Diffraction FRAZAR RAYMOND KAY Boston Los Angeles Correlated SAE and AISI Revised Standard Seattle Features DIX, Manager Reader Service Raymond Kay, 2420 Cheremoya Ave., Los Leonard, 100 East 42nd New York Peirce Lewis, 7310 Woodward Detroit 100 East 42nd New York News and Markets CHILTON COMPANY Member, Audit Bureau Circulation Indexed the Arts Index. Machine Tool Activity 162 able ress ronage Iron and Steel Scrap 166 7 q Finished Steel Prices Offices Advertising Offices Chestnut and Sts. 100 Eost 42nd St. Philadelphia, Pa. New York, OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, Vice-President GEORGE GRIFFITHS, Vice-President Products Advertised EVERIT TERHUNE, Vice-President VAN DEVENTER, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary Copyright, 1942, by Chilton Company (Inc.) JULIAN CHASE, THOMAS KANE, DUFFY CHARLES HEALE 4 / } i ) i 4 ice a J ¥ 42—THE IRON AGE, April 1942 Through Peace and War Century Service— 100 peace and war— good times and bad—Ryerson has served industrial America. every other crisis, continue provide steel meet the emergency requirements our nation war. APRIL 1942 ° ° ESTABLISHED 1855 More Head Work, Less Foot Work year will put into American factories nearly many new machine tools would have put into them previous normal decade. This year and next, will train and induct into our manufacturing industries new workers, either additions replacements, nearly many men and women were employed all our manufacturing industries the boom year 1929. means just this: Under the spur war, are giving our produc- tive capacity and our technical skill boost which two years would equal what could expected from years normal progress. Think what this means the present and the future mer- chandising. Normally, production follows sales. the course normal events, could have expected, with sales leading production, have arrived 1953 the productive capacity position will 1943. When the war over will find Production years too big for his breeches. There will but these two alternatives. Either put Pro- duction Hollywood reducing diet and risk anemia, make him new pair pants. Merchandising the only tailor who can that. The immediate job facing the selling profession get smart that can catch with production. big job, but not im- possible one. With this big job do, seems talk think about dis- mantling sales organizations scuttling merchandising ships; con- template putting salesmen advertising the shelf elsewhere where skill will dry and blow away foolish laughable were not sadly suicidal. Today need production save America. But tomorrow are going need super-selling save both production and America. good industrial executive would let his plant and equipment run down, even were idle for time. would keep the machines greased, the water and steam lines repair and the power house tip-top condition. And yet, some cases, the same executive will throw his sales organization the scrap pile simply because cannot see enough leg work ahead keep them busy. There may not much leg work done our sales depart- ment today, but there more head work needed there than ever before. | | 7 q | | | | | 7 } ° ° q | 4 | | ° f | 7 | | | ® | ¥ | | | 4 | AGES Photo Signal Corps Tough Steel for Secret Process Made Inland for Special steel for small and large calibre guns made Inland for Government Arsenal. The gun barrels are manufactured secret process and require especially tough, high-quality carbon steel. Thousands tons this steel already have been made Inland, and large tonnage continues flow the Government Arsenal. Production this steel exacting specifications begins with the careful selection and blending raw materials. Furnaces must perfect condi- tion; temperatures are controlled the nth degree. Expert steelmakers and highly trained metallurgical technicians supervise each phase production, from blending raw materials final inspection. many hundred test sam- ples are often taken the heat progresses Government Arsenal make sure the chemical analysis exactly right. heat immediately rejected does not safely meet every rigid requirement. Ingot molds are thoroughly cleaned and prepared for hot topping. Billets are heavily cropped, chipped and ground eliminate all possible defects. Every ton this special Inland gun barrel steel must pass the critical examination Government inspectors before shipment. Inland has had many years experience making steels meet special requirements. are glad now able turn this skill the production steel for gun barrels—and for bombs, ships, tanks and all else needed for Victory the war against aggressor nations. PILING REINFORCING BARS RAILS TRACK ACCESSORIES Sales Offices: Milwaukee, Detroit, St. Paul, St. Louis, 4 4 zi 7 7 7 7 7 7 basis, particularly soures, have directed increased at- tention the economic ization pig iron. review (re- port No. 191) developments this direction the blast furnace committee Verein Deutscher Eisenhiittenleute, published recent- Stahl und Eisen, describes some research undertaken the works August Thyssen Hiitte A.G. establish the comparative efficiency various desulphurizing processes. The review points out that much care required taking samples, for the sulphur rarely uniformly distributed, and tapping usually found drop off the end the run. Thus, initial sulphur value 0.18 per cent has been observed drop 0.09 per cent the end the tap; another case the ex- values were 0.168 and 0.046 per cent, or, over range 4:1. Samples should, therefore, taken intervals throughout tap and average calculated from these. This wide difference the sul- content throughout tap sug- gests that desulphurization might effected the blast furnace it- self, maintaining sufficient amount reactive slag over the molten charge. The marked drop sulphur content due the fact that enough slag present the furnace, the drops iron be- come desulphurized their passage through the slag, that the thicker the slag cover, the greater the de- HANGES the raw material Desulphurizing Pig This report German research into desulphurization practice has especial significance for the steel in- dustry strains meet the ever increasing war de- mand for pig iron supplies. The tapping new ore sources, particular, has intensified the need for more complete data this subject. gree desulphurization. For in- stance, Oelsen points out that sodium silicates can remove ap- phides from molten charges. The authors point out that de- sulphurization pig iron the blast furnace through the medium furnace slag was actually pat- ented Germany 1907. Soda Ash and Lime Following ments, observations were conducted, the review states, over 200 tap- pings with each two blast fur- naces; one operating with soda ash and the other with mixture soda ash and lime. The vast amount data collected did not reveal any TABLE Desulphurization Experiments Furnace Temperature, 2,500 2,480 Amount soda ash, per ton pig iron 16.17 Amount lime, Per Cent Cent 0.097 0.105 0.65 0.95 Reduction 54. 66. 0.052 0.069 Reduction 20.5 26. Reduction inMn 0.065 Efficiency 28.8 32.4 clear and simple connection between the degree desulphurization and the proportions and the start the process and their varia- tion during tapping, with the temperature the iron. The effect the initial sulphur value was, however, pronounced, for desulphurization became more ef- fective the sulphur value in- creased, using the same amount soda ash. The increase was not exactly direct proportion, de- sulphurization could not taken beyond per cent. The de- sulphurizing action was better furnace than furnace (Table There was also greater re- duction silicon content when us- ing soda ash alone, spite low initial concentration, than wher using soda-lime mixture. The re- duction manganese was roughly the same both cases. The degree and reduction indicates that the removed soda ash was not wholly present manganese sulphide. The results these ex- periments are Table addition, comparative tests were made with two ladle charges tapped the same time from the same furnace. One 30-ton charge received 440 soda ash and the other mixtures soda ash and lime, with soda- lime ratios 198/198, 264/198, 264/264, 330/198, Again, the higher initial sulphur showed better soda ash reaction, the reactivity increasing with sul- phur content more rapidly when THE IRON AGE, April 1942—45 4 ‘ il | 3 | q 7 : 7 q q x ; } iy, | | q q | using the mixtures than with plain soda ash. High values are usually asso- ciated with low iron temperatures, and owing their greater quantity, the effect the mixtures limited compared with soda ash alone. The general conclusion already viz., that the lower the final value required the pig-iron, the less must the amount removed per unit mass the desulphurizing agent. The final value just im- portant the initial content, sulphur elimination being after all the object the process. The rela- tionship between final values when using different mix- tures can indicated graphically, the plot serving give the most suitable mixtures for any partic- ular terminal values. Discussing this question, the review indicates that the marked superiority certain cases 4:3 soda ash/lime mixture over 5:3 mixture and plain soda ash, this result applying only reaction the blast furnace and confirmed experiments three iron works. Double Na-Ca Oelsen has called attention the formation double carbonate fusing together soda ash and CaCO, this carbonate melts 1530 deg. some 120 deg. lower than soda ash. would appear that this salt should exer- cise powerful desulphurizing ac- tion, especially the fluid state. experimental work conjunction with the Kaiser Wilhelm Institute fiir Eisenforschung, the double salt was molten and then added the iron, when caused violent reac- tion. Contrary expectation, de- sulphurization was found less efficient than with plain soda ash; the same result was obtained with the sintered carbonate. The reason for this failure that the highly fluid salt after reaction forms very viscous slag, which may solidify and then become total- ineffective. Experiments were also conducted find difference, any, between the action solid and molten soda ash; with in- itial sulphur 0.10 0.13 per cent, sulphur elimination (2.20 solid soda ash better than with the molten reagent. Various advantages accrue de- sulphurization effected after the mixer, for: (1) The pig-iron poured from the mixer contains fur- 46—THE IRON AGE, April 1942 nace slag and none the silica which fine state division mixed with the iron; (2) tempera- tures are more uniform than the furnace; (3) initial sulphur being more uniform the amount soda ash added can more ac- curately determined; (4) con- stant-weight charge can used the ladle and hence the amount soda ash added can (5) the final value can ad- justed required for subsequent operations; (6) the use molten soda ash simplified; (7) lower- lime and richer-alkali slag ob- tained; (8) there better protec- tion against soda-ash dust, and (9) the durability the mixer increased soda slag residues reach the mixer. The disadvantages are the lower temperature the pig iron and hence lower reactivity the de- sulphurizing agent, and also probable reduction converter life and desulphurizing efficiency the converter, owing the pres- ence the soda slag. High Mixer Output Experiments show that good re- sults can only achieved the output the mixer maintained fast enough keep the pig iron hot. the main experiment 3500 tons non-desulphurized iron was passed through the mixer and the temperature kept the right level. the first trials the amount soda ash used intentionally taken very high; later was re- duced. was obtained the 60th ex- periment, after which reduction the furnace temperature caused TABLE Effect Initial Sulphur Soda Ash added Final Initial Sulphur Pig Sulphur Per Cent Per Cent Per Cent 0.060 0.080. 0.323 0.036 Average 0.0685 0.386 0.040 0.532 0.035 0.080 0.100. 0.386 0.041 Average 0.090 0.532 0.045 0.645 0.0427 0.323 0.061 0.100 0.120. 0.386 0.041 Average 0.106 0.532 0.051 0.645 0.042 Average 0.138 0.058 0.062 the sulphur reach maximum 0.16 per cent, which naturally re- acted adversely the reduc- tion. Desulphurization below 0.04 per cent was achieved the excep- tional cases only, irrespective the amount soda ash added. Tests showed that even small quantities soda ash are sufficient desul- phurize down normal levels, that is, 0.105 0.12 per cent with about soda ash per ton. Further tests with soda ash/lime mixtures gave negative results, and even the quantity soda ash the mixture was the same with soda ash alone, the desulphurizing action was reduced the presence lime. The greater heat absorbed the mixture adversely affects the temperatures after the mixer, and the slag becomes very viscous and inert. The soda ash required for desulphurization behind the mixer roughly half that needed for similar result the furnace. not always possible reduce the content below certain final value continually increasing the amount soda ash added. The practice is, therefore, use just much soda ash will sufficient reduce the the required final value, taking guide the data given Table II. point noted that the soda slag must not pass into the converter when the poured into the ladle; the authors recommend the use slag catcher the type adopted Corby, which permits part the slag used again and thus reducing soda-ash consumption. Desulphurizing With Lime The production low sulphur pig iron from high sulphur purple ores led tests being made the feasibility desulphurizing pig iron rotary furnaces using lime alone. large scale test conducted the Mannesmannréhren Werke resulted the desuiphurization tons pig iron from 0.186 0.035 per cent 117 min., open- ing new possibilities and leading further work Hamborn rotary furnaces heated with coke oven gas. Desulphurization was found take very rapidly iron with about per cent and 1.5 2.5 per cent Si, the reduction being from 0.94 0.53 per cent min.; after this there abrupt and continuous retardation the rate reaction. The original trials Stiirzelberg seemed indicate that satisfactory reducing condi- tions could not obtained furnace heated with coke oven gas and that desulphirization would, therefore, inadequate. This was confirmed the Ham- born experiments, and led tar oil being added create suitable reducing conditions. Neither this nor other changes the fuel gave better results and reasonable de- sulphurization was only obtained the repeated addition fresh lime. The furnace was next modified burn pulverized fuel. The requisite reducing atmosphere then readily obtained. Desulphurization was very rapid during the first min. when the pig iron came contact with the fresh lime. one experiment where 800 kg. lime and 440 fine coke were added 5-ton charge, the sulphur was re- duced from 0.21 0.032 per cent hr. These and other experiments in- dicate that desulphurization with lime rotary furnace prac- tical proposition, giving desulphur- ization rates 0.35 per cent per hr. with per cent lime consumption and the addition per cent carbon for reduc- tion. noted that the reaction does not take place uniform rate; may take some time become initiated, may start high speed and rapidly decay slow rate. Desulphurization can taken extremely low values the rotary furnace, but this requires long APPING blast furnace the Bethlehem plant the Bethlehem Steel Co. ° time. unexplained feature this process the very large amount iron which lost. Hamborn the iron yield was only per cent the experi- mental plant. believed that these losses can reduced cut- ting down the quantity lime added. Lime Blast Tests Oelsen has also described the re- sults laboratory desulphurizing tests using finely ground lime, which the was reduced very low values employing temperatures 2370 2550 deg. This led further tests with acid-lined ladle which was reconstructed allow powdered lime blown through the charge. The lime was finely ground and the air for blowing kept min- imum. Coal dust could also added the lime give excess reducing agent against the oxygen the blast. adding 3.5 per cent lime, the was reduced from 0.12 0.065 per cent 0.75 min., and the being reduced from 0.47 0.4 per cent. The manganese content remained unchanged. another experiment acid iron had the sulphur reduced from 0.32 0.069 per cent three stages intervals 1.9 min. The came down from 1.69 1.44 per cent and the from 9.47 0.32 per cent. law could deduced from these first tests. The temperature drop was considerable owing transferring the cold ladle and the loss correspondingly high. conditions are suitable, de- sulphurization with manganese the formation sulphide can extremely efficient. one experi- ment was reduced hr. from 0.49 0.29 per cent, while the sul- phur was lowered from 0.17 0.09 per cent. high degree desul- phurization which was thought could only obtained with soda ash can thus also obtained with THE IRON AGE, April 1942—47 | 7 j | ‘ ) d f q 3 E q q TABLE Ill 14.30 14.30 4.40 14.30 Ore Geier Geier Poti Geier Change Coke 4.40 4.40 Lime 4.40 8.80 2.86 6.60 Initial Values, Per Cent: 0.24 0.07 0.27 0.32 0.38 0.65 0.12 0.34 1.04 1.00 1.45 Reduction, Per Cent, Per 0.205 0.415 0.045 0.152 Increase Per Cent, Per Hr. 0.34 0.83 0.43 Yield, Per 15.4 53.0 26.5 Absolute 0.058 0.19 Loss, Per Cent) Relative 63. 59. 48. 56. comparatively low values. another case was reduced hr. from 0.27 0.07 per cent and the sulphur from 0.49 0.36 per cent. The and the are hence reduced roughly the same ratio the amount sulphide formed. cooperation with the Kaiser Wilhelm Institut fiir schung, Oelsen suggested utilizing the reducing power liberate from its oxides the ore and carry over the pig iron. The occurring iron sulphide the new design, the brightness and glare usually resulting from fluorescent lighting have been eliminated recently de- veloped “Spatial” lighting system, use for the first time the en- gineering department the Fair- child Camera Works, Jamaica, The new lighting design was developed Ainsworth pig iron then transformed into sulphide and separates out. Pulverized Fuel Used This was tested the pulverized fuel heated rotary furnace (1) preliminary reduction the ore with carbon, chief purpose which remove the iron from low ores, the rest the being re- duced later the the pig, and (2) reducing the ores with sili- con alone. The ores used were Geier ore with per cent Fe, per cent Mn, less than per cent CaO, and per cent SiO, and Poti ore with under per cent Fe, per gent and per cent SiO.. special advantage the proc- ess that with acid bessemer charge need added the charge, thus excluding resulting low yield Mn. The results these tests are given Table and show that tests and reduction was satisfactory, while the reduction was just tolerable. experiment with Poti ore without preliminary re- duction, the reduction was ex- ceptionally good, just experi- ment with Geier ore. The rates desulphurization, especially test with low in- itial were quite small. Against expectation, the reactions took place comparatively slow speed. Observations were the main dis- continued after one hour, this period being regarded the eco- nomic limit. The process appears quite practical, however, with high and siliceous pig iron, rate desulphurization 0.4 per cent per hr. being obtained some cases. The basicity the slag does not appear have serious influ- ence, even when the basicity fluctuated the wide limits the re- action was barely affected. Lighting Eliminates Glare Lighting, Inc., 239 East 44th St., New York. new style steel and plastic chassis used hold the fluor- escent lamps, weighing ex- clusive auxiliary coils, and man- ufactured hold two fluorescent lamps. shows saving about 100 per cent steel over many types FTEN with fluorescent illumination, lighting illustrated the left re- sults, but with the use lighting, shown right, illumination more intense, glare eliminated, and light more uniform. 48—THE IRON AGE, April 1942 fluorescent lamp chasses, and car- ries either 2-lb. plastic reflector for drafting room illumination 5-lb. reflector for factory light- ing. All parts the chassis are re- movable for cleaning without dis- turbing the lighted lamps, and made 8-ft. lengths that lock end-to-end with simple interlock- ing keys, without the use screws bolts. one three-wire elec- trical outlet, running feet fluorescent lighting can stalled. Supports, 8-ft. intervals, consist 3/16-in. steel rods, in. long that attach either toggle bolts hung ceiling ex- pansion bolts concrete slabs. design, the brightness the plastic reflectors fades into the ceiling, eliminating the brightness differences that cause glare effects usually present with fluorescent lighting. = : ~ a 4 a ‘ 1 q Aluminum Rotor Casting tric motors expansion the rotor casting department Reliance Electric Engineering Co., Cleveland. department casts rotor bars, short circuiting rings and fan blades integral unit eliminate con- nections which might otherwise loosen under severe service con- ditions. Laminations for the rotor core are stacked arbors, assembled into molds and placed the casting sometimes preheated guard against premature chilling and im- proper filling the casting. Two casting presses inject molten aluminum 1250 1420 deg. One self-contained oil operated unit, the other pneumatic. While the casting operation requires but few seconds, pressure main- tained the mold for period long enough permit chilling the metal and allow fumes ex- hausted the blowers mounted each unit. After the mold has been stripped from the casting arbor press adjacent bench the casting placed key-seater. Here, what essentially broaching op- eration, cutter with multiple set teeth cuts final dimensions the keyway for the motor shaft. Directly above the two casting presses exhaust fan with ca- pacity 10,000 cu. ft. air per min. combination with two hp. exhaust fans the side walls provides for changing the air the shop often three times minute necessary. minimize noise and vibration, the side wall fans are mounted channels which extend from the floor the ceil- ing. They discharge steel shuttered apertures the side wall. separate vent line and motor driven exhaust blower serve the preheating oven. The two aluminum melting pots which serve the presses are well in- demand for elec- casting presses produce rotor bars, short circuiting rings and fan blades integral unit eliminate connections which might loosen severe service. Bey wr ee left, which broaches keyways rotor castings. The operator right assembling rotor core laminations arbor. casting press fitted with safety hood and exhaust fan. sulated with specially designed cov- ers which can readily removed give access the furnaces. Two- inch thick insulation used the sides the enclosures with in. insulation the tops. The latter are made two sections mini- mize exposure the hot metal when necessary add ingots, skim off slag insert pyrometer rods. reduce heat loss from the ladles when the covers are closed, the latter are equipped with spring seals and are motor operated that their opening and closing ac- Each die tions will positive. The furnaces are set slightly off center beneath the ladles permit skimming slag off over the side and down into fur- nace pans below. Two overhead, one-ton, chain pull hoists travel the length the shop and provide complete the entire area the casting room. Care has been taken arrange the equipment the room leave suf- ficient space around all machinery provide room for skids bearing incoming material and outgoing fin- ished parts. THE IRON AGE, April q | q 4 Wich fo constant aim foundry- men throughout the years has been develop methods casting production which will give precise reproduction pattern de- tail and which will permit working reduce, not completely eliminate, machining operations. One the more recent steps that direction has been the use plaster mixtures for molds production basis. Research and de- velopment work carried Morris Bean the Antioch Foun- dry, Delco-Remy Division eral Motors Corp., extended the knowledge the char- acteristics plaster molds. Bean has also been able develop meth- ods* controlling these character- *See patent 2,220,703, Nov. 1940 issued Bean. istics remove some the obsta- cles which have past years deterred the use plaster mold mixture. Use plaster molds, according Bean’s specifications, provides medium especially well adapted for casting large, highly stressed parts aluminum close tolerances. addition G-M plant, the foundry division Menasco Mfg. Co., operating under G-M license, 50—THE IRON AGE, April 1942 also employing the Antioch proc- ess substantial basis pro- duce wide variety aluminum castings. Generally speaking, ideal molding medium must have easily controlled shrinkage expansion characteristics (ideal, course, would medium devoid either shrinkage expansion), high per- meability, fine surface texture, high but low strength after pouring and con- trollable thermal conductivity fac- tor. far plaster molds are con- cerned, the difficulty the past has been develop mixtures and processing techniques which would give all these features. Many meth- ods have several but none has all these features. This requires constant juggling qualities suit each individual casting job. simply driving off the water crystallization and permitting com- plete dehydration, obtain mold investment that will record the fin- est detail and will have little shrink- age small molds. material has too great shrinkage permit its use for large castings and its low thermal conductivity prevents its use for casting heat treatable aluminum alloys which re- quire rapid freezing. Menasco reports that their ex- perience with the Antioch process has indicated that Bean has devel- oped material that limits expan- sion uniform amount about ° ° ° RAYMOND KAY Southern California Editor THE IRON AGE 0.001 in. per in. length. The mixes required suit the char- acteristics the various metals and types castings produced Menasco have practically uniform qualities permeability, tensile strength and compressive strength. possible very economically produce heat treatable castings which require rapid freezing. the Menasco plant, aluminum alloys No. 195, 355, 356, and heat treated are being pro- duced. Castings No. 214 and No. are being cast. Alloys No. 12, 40, 108, and 112 can cast, but thus far there has been very little call for this group the area supplied this plant. Alloy No. 220 (high Mg), asserted, cannot cast economically. The average weight castings and are such size that in. flask will hold four castings. Flasks various sizes are used required fit specific jobs. The smallest casting weighed about 1/3 oz., while the largest was 350 lb. This latter cast- ing was ft. long, with metal thick- ness varying from in. in. Actually, there limit the weight castings that can made the Antioch process, other than the practical limitations han- dling and drying the mold sections. The Menasco foundry has been working with this process job orders for over year and half ascertain the economic possibil- ities the process and develop techniques for heavy production. The average production the plaster foundry Menasco has been about 400 molds day, ap- proximately 800 metal. great deal research work has been done attempting praise the 7 7 ments possible with the Antioch process compared with sand cast- ings. This study has been possible the fact that Menasco operates sand foundry well plaster foundry. The two chief disadvantages Antioch castings found the com- mercial jobbing field, according Menasco, are the present compara- tively high cost per pound (com- For description another plaster mold procedure, the Capaco process, see Ace, Oct. 1941, 74. pared with sand castings) and the length time required tool the foundry with the precision pat- terns required obtain the full benefit the process. far the cost per pound concerned, this being overcome educating casting buyers think the basis the final cost the casting the assembly, rather than the foundry cost. other words, the savings machin- ing and the design possibilities Antioch castings must calculated against the foundry cost the casting. Aluminum Castings... Use the Antioch plaster mold process for the pro- duction highly stressed aluminum castings unusually close tolerances described herein for the first time. The foundry tooling process for Antioch castings requires some four five weeks. This time in- cludes the development patterns, casting pilot pieces and the ing production technique. How- ever, after production methods are established, the molds can turned out the rate four hour from one cope and drag pattern. highly complicated mold consist- ing several large sections moves more slowly, course, and may re- quire much hour for mold- ing. The heart any casting, regard- less how produced, the pattern. This especially true with plaster molds. Too often casting buyers want good castings from bad patterns. correct this situa- tion, Menasco has established its own pattern shop fulfill the pre- cise pattern requirements the Antioch process. Antioch patterns follow the gen- eral design sand patterns when- ever possible. The employment metal patterns, metal match plates and metal cope and drag plates are essential. The chief differences, however, lie the ultra precise dimensions which are established. Shrinkage allowances Antioch patterns are the same for sand. cases complicated pattern which can made economically only using wood model, Gypsum’s non-expanding Hydrocal used advantage. master mold cast around the model and reverses its various sections are then made. Such temporary pat- terns, augmented Cerromatrix aluminum strips parts exposed chipping abrasion, are good for runs about 500 castings. Protective coatings are available enable wood patterns with- stand the moisture the plaster IG. Menasco plaster mold aluminum castings. the center the bottom row can seen super- charger impeller. This highly stressed piece, but has wall thickness only Note the lower right thin-walled casting with several re-entry curves and varied wall thickness. The heavy-walled center casting hydraulic application. The generally thin walls these pieces especially noteworthy. THE IRON AGE, April 4 8 q | | “ 1 q mix that about molds may made from good wood pattern. Where close tolerances are not vital, thermo-plastic rubbery ma- terial known Korogel occa- sionally used advantage sim- plify pattern design, especially where undercuts are involved. Draft Requirements While possible work with unusually small draft, standard practice allow about 0.004 in. for the first inch, per side, sim- plify production. After the first inch, draft 0.002 in. possible. some pieces having one angular wall, draft angle min. may readily cast without the use cores. Web thicknesses which can gates, runners and risers into cope and drag patterns after locations have been determined pilot castings and X-ray studies. 52—THE IRON AGE, April 1942 LEFT stressed casting was formerly made welded sheet steel. has wall thickness 1/16 weighs oz. and good exam- ple the applica- tion this process. RIGHT 3—This heat treated alumi- num casting weighs scale are dependent upon casting size and shape. Wall thicknesses in. can kept within 1/64 in.; 3/32 in. wall areas can cast sections in., while 1/16 in. walls have been cast areas in. square. Non-heat treated rings in. diameter and weighing 350 lb. have been cast diametrical tolerances 0.001, 0.010 in. Normally, overall tolerance 0.015 not difficult, and toler- ance 0.01 in. practical. Dimensions lying within the same half mold within the same core can held tolerances 0.003. The Antioch process especially adaptable where complicated coring problems exist, where compound curves are required for contact with other smooth surfaces and where parts important. Investment Composition The-investment mixed ac- cordance with the casting require- ments, the density the mix hav- ing controllable effect upon the thermal characteristics the mold. The proportion the various mate- rials also varied. typical mix- ture parts calcined gypsum, parts silica sand, with small amount fibrous added ac- formation granules the recrystallization process. this dry mixture, water added, the average amount being about parts water 100 parts dry Steps Producing Antioch OURING the plaster investment. This mixture allowed set for about min., following which the mold stripped. Prints and alining pins are used setting the cores. | 7 mix. The technique mixing and handling plaster well known the ceramic industry and the dental profession and procedures are used Menasco. The accelerator addition can such material particles set plaster, epsom salts, potassium citrate, etc. Various patented mix- tures are also available that will prevent expansion during setting. The patterns are surmounted with flask and the liquid mixture poured in. The molds are set racks and wheeled into autoclaves where they remain for about hr. Steam pressure and 260 deg. F., employed this treat- ment. Leaving the oven, the molds are permitted reset the air and this period that granular structure develops within the mold. Roughly hr. are required for this resetting. Following this treatment, excess water removed from the molds drying ovens where air 350 deg. circulated around them. This drying operation takes from hr., depending upon the mold section. After cooling room temperature, the metal poured into the molds gravity. Mold Permeability The treatment given these molds makes possible for unused mold stand several days without any important change moisture Castings the Menasco Foundry 4—The application this casting requires unusually close tolerances. cast heat treated alloy, weighs and in. long. content. The finished molds have permeability A.F.A., with tensile strength per sq. in. Chills can used sand cast- ing. Sufficient time has not elapsed permit dogmatic statement the economic position Antioch proc- ess castings, Menasco feels. the present time the cost these cast- ings between and times greater than comparable sand units, the as-cast condition. This spread, however, counter- balanced the greater accuracies and more complicated castings that ‘an produced plaster molds. The elimination machining RYING the molds. Gates and risers are sealed during plaster molds. processing keep out foreign matter. This operation takes from hr., depending mold size. operation, all pouring being done gravity. While this article was preparation, the foundry division the Menasco Co. was sold the Osbrink Co. This latter company will continue along the lines developed Menasco. valuable not only for the reduction overall casting costs, but also shortening processing time. ex- perience gained, substantial re- ductions present costs are rea- sonably expected. discussion the means ob- taining the characteristics the plaster mold, which are the heart the process, may interesting this time. The desired character- pressure used for this the right background can seen the match plate flasks. THE IRON AGE, April 1942—53 | q 4 D : J a macrographs show plaster mold investment various stages. Left view shows the surface {16 diameters) mold before processing and drying. The fine dots are sand grains visible through the surface film. due pattern imperfections. Center (16 diometers) the interior structure after processing and drying. White areas are granules containing one more grains silica sand. The dark areas are Right shows the surface after casting has been poured against Note that the surface still smooth and unbroken. istics are achieved, fundamentally, treatment where re-crystal- lization process occurs within the plaster mixture. This accom- panied growth the larger crystal grains the expense the smaller. Thus, mold produced which composed thin, porous, fine- grained surface layer, backed body larger granules. The plaster, when the mold poured, still contains most its water molten metal runs over the surface, the endothermic action the de- hydration aids chilling the metal. This recrystallization phenome- non effected, first, controlled heat treatment for uniform conver- sion the calcium sulphate hydrate the mold the hemi- hydrate condition; second, auto- matic saturation the body the mold with moisture sufficient, not it. only reconvert the calcium sul- phate di-hydrate, but pro- vide excess water the interfaces which the recrystallization can occur; third, the maintenance such conditions favorable the re- crystallization until the desired re- distribution into larger grains has and, finally, the termina- tion such conditions drying. The most practical and satisfac- tory method obtaining the de- sired uniform dehydration subject the entire mold atmos- phere slightly ture sufficient effect the desired dehydration. The autoclave treatment regu- lated that approximately the water crystallization the gypsum plaster liberated—i.e., the di-hydrate converted hemi- hydrate—but the liberated water not evaporated because the treat- The light horizontal lines are surface scratches ment takes place atmosphere saturated with water vapor. Upon the release pressure from the autoclave, the mold wet through and recrystallization the calcium sulphate di-hydrate begins immediately. The free water drawn away from the surface toward the interior capillary ac- tion, that the granular structure stops just short the surface the mold resets. Use plaster mixes the past has been restricted because the excessive and variable shrinkage upon their required complete de- hydration; their very low strength after this dehydration, and their low heat capacity. The treatment described this article overcomes these objections and provides means controlling all the char- acteristics desired mold, ac- cording Menasco officials. Electrolytic Polishing Silver bertson and Otis Fortner covering the electrolytic polishing silver process anodic cor- rosion are described paper given before the general meet- ing the Electrochemical Society Nashville, Tenn. current den- sity carefully regulated bath silver cyanide, potassium cyan- ide, and potassium carbonate and room temperature the bath and 54—THE IRON AGE, April 1942 sufficient stirring prevent layer formation are maintained, the re- flectivity the resulting surface appears high as, not higher than, that mechanically polished surface. The process depends upon the formation anode film that soluble the bath under suitable conditions current density, tem- perature and free cyanide concen- tration. The method polishing affords means preparing silver specimens for etching and micro- scopic examination without intro- ducing any possibility mechan- ically work-altered surface layer. Etching may carried out the polished surface the usual man- ners, either the use corro- sive agent such chromic acid, making the specimen anodic cyanide plating bath and etching low current density. q | 7 OUNTING demands for poses continue emphasize interest new processes for its Killeffer, recent issue Chem- ical and Metallurgical News, the latest these employs ferrosilicon reduce calcined dolomite free metallic magnesium which then distilled from the reacting mass. Production the light metal the United States has far been lim- ited the electrolysis magne- sium chloride obtained from natu- ral brines and from sea water to- gether with small amounts from the Hansgirg process based the re- duction magnesite with carbon. new ferrosilicon process has the Canadian National Research Council. Pidgeon found that the reaction between ferrosilicon and magnesium oxide proceeds smoothly practicable temperatures under vacuum the presence oxide. Metallic magnesium distills readily the reaction temperature and condenses extraordinary condenser tube connected with the reaction retort. The process consists briquet- ting ground ferrosilicon (75 per cent higher silicon content pre- ferred) with dead burnt dolomite and heating these briquets alloy steel retort about 1150 deg. (2102 deg. F.). The retort constructed with integral con- denser tube into which removable, tubular steel lining fits. The retort and condenser are evacuated low meter), and the reaction pro- ceeds, pure metallic magnesium condenses the lining the con- denser. the end the run— including time for evacuation, the cycle about hr.—the condenser liner removed with its accumu- lated magnesium. Differential con- traction the steel and magnesium breaks the two apart and the mag- nesium “pipe” ready the foundry without further purifica- tion treatment. The retorts used Magnesium from Dolomite resemble those the industry and can heated any conveni- ent manner, using gas, coal elec- tric heat. The advantages claimed for this process are several. The process equipment comparatively simple: cast alloy steel retorts which em- body minimum machine fin- ishing, furnaces for heating the retorts, and vacuum pumps evac- uate them. Dolomite plentiful and easily calcined standard lime-kiln equipment. Ferrosilicon made this country huge scale standard electric furnace equipment from plentiful raw materials. The reaction proceeds smoothly without hazard. evolution handling gases involved, and when the retorts are opened, the magnesium solid massive form precluding the possibility explosion fire. Special emphasis placed the relatively low investment plant required and the speed with which units can built the present emergency. Furthermore, pilot plant operation date has amply proved the process, and con- struction production plants already under way. Several companies have become actively interested putting this process work. Canada, Domin- ion Magnesium, Ltd., operating pilot-scale plant. This operation tons per day. The process depends the simple reaction between magnesium oxide and elementary silicon contained ferrosilicon: Subsequent reaction between the SiO, formed and the calcium oxide the charge forms infusible di- silicate that can easily removed from the retort the end the run without slagging. gas evolved involved the process. Based this reaction, each pound silicon the charge should theoretically produce 1.73 Ib. metallic magnesium. terms per cent ferrosilicon, each pound magnesium produced requires practically lb. alloy. The simplicity the operation depends further the fact that powerful reducing agent, ferrosili- con, supplied the process. This must manufactured elsewhere, and although the raw materials re- quired for are plentiful, the en- ergy needed high and the demand for the product the steel indus- try great. Production ferro- silicon all grades the United States 1940 was 406,699 net tons. The average silicon content this entire output was per cent. In- cluded the total are alloys con- taining little per cent and much per cent elementary silicon. The lower grades were pro- duced blast furnaces whose total output was 190,310 tons. Electric furnace operation supplied tons higher concentration alloys and 248 tons were produced by-product electric furnace abra- sives. Present rate production over 700,000 tons per annum. Because the need for ferrosili- con war work, the present fixed price ceiling for the per cent grade $135 per net ton. this basis and assuming that ferrosili- con the required grade avail- able sufficient quantity, the cost magnesium the Pidgeon proc- ess should well below the present market price 22.5c. per Ib. When these facts are considered with the obvious advantages the process and the further considera- tion that the operation can car- ried out relatively small and widely distributed units, the desir- ability utilizing ferrosilicon reducing agent with dolomite the expanded magnesium program once becomes patent. Super-Quench New Oil NEW quenching Quench—that said have faster cooling rate than any other known quenching oil, has been de- veloped Gulf Oil Corp., Pitts- burgh. claimed that has cooling rate intermediate between oil and water through the harden- ing temperature range, and re- tains the slow speed oil below this range. Developed after search, the new quenching oil makes possible maximum physical proper- ties, but institutes more distor- tion than ordinary oils. has been proved service many types steels and various shapes. THE IRON AGE, April 1942—55 | 7 { 3 3 } q 7 7 q 4 - NALYSES heats poured the steel foundry the Gen- eral Electric Co. the Sche- nectady Works are carried out 24-hr. basis, with quantitative analyses being routine practice with two-man staff, one man time being duty. While foundry’s normal six melts each hr. for analy- ses, this number can easily in- creased around 100 under exist- ing operating conditions the new laboratory. Indeed, with longer used short cut method, involving less weighing due the use quickly measured portions for dif- ferent analyses, 145 determinations 56—THE IRON AGE, April 1942 have been performed during 24- hr. period. The laboratory operat- ing staff consists Mr. Gerald Zeh, charge, and Mr. Sax. For each the usual six heats run the foundry each day, four preliminary analyses are made— duplicate carbon, manganese and molybdenum determination. These are made ascertain the amount these constituents present the steel being melted. Based these findings, the composition the melt altered until the desirable amounts are present for the type metal wanted. From another sam- ple, made after addition various the melt, the final analyses are made for eight constit- uents, which include two more car- bon determinations. Since the preliminary analysis and the final carbon analyses con- stitute half the tests made, interest see how the four pre- liminary analyses are carried out ‘less than half hour. claim made that the methods used are new original, but convenient placing apparatus has resulted the speed with which results are turned out. Carbon Determinations For carbon determinations, 1.3636-gm. sample steel, one half this weight for cast iron, placed aluminum oxide nox) nickel boat set quartz tube running through electric furnace about 1470 deg. Puri- fied oxygen made passing tank oxygen, way reducing valve, through sulphuric acid-chromic acid mixture, then dehydrate (magne- sium percholorate, tri-hydrate) and finally Ascarite asbestos). This passed over the metal remove carbon forming carbon dioxide. The exit gas taken through the first two reagents, emerging oxy- gen and carbon dioxide, both dry. then enters weighed (counter- poised) drying more dehydrite and then Ascarite. The latter picks the carbon di- oxide, the amount being determined re-weighing. Molybdenum Molybdenum determined the colorimetric method. Sometimes special steps are necessary for spe- cial samples, but the usual proce- dure follows: (1) Weigh 1/10* gm. into 125- milliliter Erlenmeyer flask. Add c.c. per cent (asbestos filtered) gram samples are used for molybdenum below 0.10 per cent, with smaller samples for higher percentages. technical perchloric acid. Heat be- yond the appearance dense fumes the point where the fumes have retreated until they seem only hover over the flask mouth. Cool Analysis slightly and add water, then complete cooling. (2) Add per cent NaSCN. Shake, add 11.2 per cent (containing per cent concentrated HCl) and shake. The orange color the mo- lybdous thiocyanate shows when the red color from iron has been de- (3) Transfcr 250 sepa- ratory funnel and add Technical grade butyl acetate saturated with NaSCN, then with SnCl., using excess these solutions and each time utilizing separatory funnel. Re- peat this necessary dilute the ma- terial. ° DR. ALBERT TITUS Schenectady Works Laboratory, General Electric Co. The technique employed the G-E steel foun- dry laboratory obtain 100 routine quantitative analyses 24-hr. period with two-man staff de- scribed herein. treated** butyl acetate from bur- ette. Add NaSCN and c.c. the SnCl,. Shake, then sep- arate, keeping the upper layer. Let stand. Again drain off the lower layer. Run the orange-colored butyl acetate solution into 6-in. test tube. (4) Six-inch test tubes contain the standards. They are permanent 2—Titration table the new G-E steel foundry laboratory. The background fluorescent lighted. THE IRON AGE, April 1942—57 7 > x ° ° ° ° ° | | for few week