The Iron Age 1943-04-22: Vol 151 Iss 16

INCREASES UNIFORMITY Hydraulic Tube Pointer tubes maximum outside diameter. Furnished <omplete rack, feed table and he } 4 4 SIGNERS AND BUILDERS THE STEEL, NON- NON-FERROUS AND CHEMICAL News Techr Reg Ww. Robert Wherever you use metal that must withstand yr heat-treating temperatures, our Alloy in- vites your consideration. the 35-15 type, and made cast form rolled rod and work from your own designs, offer our own suggestions. Many problems like this have come our way, and they have taught Member ember considerable that, course, glad pass ishe you—if you need. know the metal, 1c Alloy 502, and think we've learned where and how apply it. So, thinking about heat-resisting alloys, write us. also electric furnaces for heat-treatment, such pot and types. Hoskins Brazing Furnaces are fast and compact. Described Catalog Hoskins Manufacturing Company, Detroit, Michigan. LEAD WIRE PYROMETERS WELDING WIRE HEAT RESISTANT CASTINGS ENAMELING SPARK PLUG ELECTRODE WIRE SPECIAL ALLOYS NICKEL PROTECTION TUBES THE IRON AGE, published every Thursday the CHILTON CO. (INC.). Entered second class matter ber 1932, Philadelphia under act March 1879. yearly North America and South America, Vol. 151, No. Vice APRIL 22, 1943 VOL. NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager Managing Editor, LIPPERT News Markets Editor, JAMES Technical Editor, OLIVER Art Editor, WINTERS Associate Editors Editorial Assistants BUTTERS Regional News and Technical Editors Washington Pittsburgh Washington Chicago Detroit OSGOOD MURDOCK San Francisco Editorial Correspondents Buffalo Cincinnati Bosto Angeles Milwaukee Birmingham SANDERSON ROY EDMONDS Torento, St. Louis BACON ° ° ° DIX, Manager, Reader Service Regional Business Managers Blair, Union Bldg., Cleveland Fitzgerald, 428 Park Pittsburgh Hottenstein, 1012 Otis Chicago Raymond Kay, 2420 Cheremoya Ave., Los Angeles, Cal. Leonard, 100 East 42nd New York Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd New York Johnson, Market Research Mgr. Hayes, Production Manager. Baur, Typography and Layout. ° ° Member, Audit Bureau Circulations Associated Business Papers Indexed the Industrial Arts Index. Pub- every Thursday. Subscription Price North America, South America and Possessions, $8: Foreign, year. Copy, cents, Annual Number, Cable Address Y." ° ° ° Owned and Published CHILTON COMPANY Executive Editorial and Offices Advertising Offices and Sts. East 42nd St. Philadelphia, Pa. New York, U.S.A. OFFICERS AND DIRECTORS HILDRETH, Vice-President GRIFFITHS, Vice-President TERHUNE, Vice-President VAN DEVENTER, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, DUFFY CHARLES HEALE This Week in... Editorial Coordination Technical Articles Ordnance Inspection Castings Surface Protection Magnesium Converting Steel Castings Melting Bushy Steel Centrifugal Casting Gas Holes Brass Castings AFA Production Conference Underwater Resistance Welding Stranded Features Assembly Line ..... Washington West Coast Fatigue Cracks Dear Editor News and Markets This Industrial Week News Industry Personals and Obituaries Machine Tool Activity Non-Ferrous Metals Iron and Steel Scrap Prices Comparison Prices Finished Steel Prices Index Advertisers Copyright, 1943, by Chilton Company (Ine.) ° ° = Office RSON United States Troops Advancing Oran. Photo Army Signal elps Make Record Delivery ACKING our fast-moving mechanized Army takes fast-moving production—swift action that starts the minute the order given, that never sleeps, and that turns out jobs days, which normally would take weeks do. Certain equipment already ashore North Africa required important alterations meet unusual battle conditions. The North Africa command The Ordnance Department said: “RUSH”! The Ryerson customer who got the order said: “RUSH”! —and fifty tons steel were immediately forthcom- ing from nearby Ryerson stock. Result: Delivery the Army one week equipment which normally would have taken many weeks produce. Army-Navy “E” Award AFRICAN the manufacturer and warm letter thanks Ryerson. unusual case? Somewhat— but typical hun dreds which Ryerson stocks and Ryerson have helped get war equipment started faster—on their way sooner our fighting men. all probability, Ryerson Steel-Service can assist you your rush war production contracts, steel required. One the ten Ryerson plants nearby. Phone, wire write; receive quick personal cooperation! JOSEPH RYERSON SON, CLEVELAND BUFFALO BOSTON PHILADELPHIA JERSEY OORDINATION. hear great deal about that today connection with our war effort. According our old friend Mr. Webster, coordinate means regulate and bring into harmonious action. Something this, that very necessary carrying out war program. war program not coordinated when you have big army but not enough guns, tanks, shoes, tents, mess kits “corned Willie” match it. Nor coordinated when the reverse true and you have more material than you have men. Thanks the efficient action our selective service the army and the volunteer recruiting policy our navy, plus the magnificent job that American industry has done and doing, men and materiel are matched today meet almost any war demands that could conceivably made upon them. But that not enough. would were fighting war here the American continent but are not doing that. have take these men and their matching materiel anywhere from three twelve thousand miles before either can made effective. Our war program, fighting the battle fronts, can not considered coordinated until transportation matches both men and materiel. APRIL 22, 1943 not know how many our troops have been transported abroad the four quarters the globe since Pearl Harbor and did know would not reveal the information, but from the published releases from ESTABLISHED 1855 various Washington bureaus, led believe that the total number thus transported the past fourteen months not much excess two million. And remember correctly, during the first twelve months our participation the first World War, sent abroad some two mil- lion more. course, during the first World War, depended upon our Allies for most our munitions. This time are not doing that and fact the situation reversed. today, addition the problem sending troops overseas, must send almost everything else also, including food and supplies for non-combatant populations. This fact, however, merely emphasizes the transportation problem. our shipping resources permit send abroad more men than have far, how long will take put army armies ten million where they will the most good? far the war emphasis has been production. have now licked this problem, primarily putting the best brains the country work it. From now on, the increasing weight responsibility will come upon transportation. Would not well ask are organized meet it? inks er— assist Inc. C | | 3 4 pag. 4 ] | Better Steels are Coming— from the Tests War Hour after hour, month after month, Inland metallurgists study not only the needs for this war steel, but also the requirements victorious America— the America that will turn again peace- time developments the crafts, and the sciences—new developments that will prove again that free peoples set the pace for others follow. Coming out the tests war are finer steels—steels that will set new standards safety and speed transportation. Steels that will help bring the newest advancements swift communications into most homes the land. Steels that will bring new conceptions beauty, convenience, com- fort, and utility—all prices that can afforded the average American. Yes, you can look forward the day when steel from Inland, now flowing 100 per cent into war products, will help build greater America. INLAND STEEL COMPANY Dearborn St., Chicago, Ill. Sales Offices: Milwaukee, Detroit, St. Paul, St. Kansas City Pp Nn m 3 a m m a e e a i | City VITAL phase the production ordnance castings inspec- tion. Foundries undertaking the production ordnance castings for the first time, well plants already producing probably have number questions mind concerning various phases such inspection. This article has been prepared with the hope that will answer some these questions and this manner prevent needless delays produc- tion and avoid the scrapping in- correctly made castings. Occasionally the necessity for ord- nance inspection questioned. might well discuss this first. rule, company man group men are assigned inspection. many cases these men also clean ship the castings. There question but that these men are conscientious, but they are apt make close decisions the foundry’s favor. Too, they are ac- producing castings for peace time applications, not war equipment. Seemingly small defects from the viewpoint ordinary commercial casting may passed filled with weld, whereas this not authorized the ordnance depart- ment. Sometimes obviously serious defects are missed. This patently cannot tolerated ordnance cast- ings which are subject extreme shock vibration. seemingly face flaw, which was passed foundry inspector, shown Fig. X-ray this flaw, Fig. reveals that large shrink area porosity lies beneath the surface. RICHMOND Chie}, Inspection Division, Chicago Ordnance District Helpful suggestions how prepare for and facilitate in- spection castings ordnance inspectors are given this article. Based extensive experience this field, the author lists some the commonest defects turned ordnance inspectors and dis- cusses the philosophy behind ordnance inspection. How this inspec- tion may used tool for lowering foundry production costs also pointed out. Fig. shows cracks another cast- ing the same type, obviously bad, but also passed the foundry inspec- tor. These parts are all subjected strain, and incorporating such cast- ings into fighting unit could have serious results. large number alloy steel cast- ings with polished and flame hard- ened working surface have been found have unauthorized welds this surface. The fact that the weld ° ° ° IG. I—A sma defect circle) artillery cast- ing weighing ap- proximately Ib. The true extent this defect shown radiograph, Fig. ° ° ° could not satisfactorily hardened meant only less resistance. However, since this part subject serious shock and constant vibration, the weld might become loosened, act wedge, and lock the entire mech- anism. numerous defective castings are found daily, large number ex- amples may cited, examples which were all found after the foundry had passed the castings. This situation THE IRON AGE, April 22, /] 4 Ol ° ° ° ri | | a f — | > ™ 2—A radiograph the defect shown Fig. shrink area, despite the small surface indication. would not very serious all flaws were revealed after machining, but, unfortunately, this not the case. Small shrinkage cracks, producing cleavage planes, may concealed after machining. course, all flaws cannot re- vealed ordnance inspection, but obvious that with such inspection smaller percentage defective parts will reach the fighting front. This not due superiority the part the ordnance inspector, but the psychological effect all con- cerned the manufacture and ship- ment the castings, when known that outside source will check the work. Superficially may seem expen- sive inconvenience. However, immediate study rejections made, and the cause removed, serious losses the foundry can avoided, say nothing loss machining time and good will later rejections. The inspector’s duty assist the foundry. This does not mean has, however, access many plants which are producing, some cases, identical material. Since other plants are producing satisfactory castings, can use their technique guide. observed difference melting technique between two plants, gating and risering pouring may disclose rather obvious fault, which one foundry had not noticed due its closeness the work. 42—THE IRON AGE, April 22, 1943 Note the extent the economical method mold- spector, will not divulged an- other foundry without full permission the more efficient foundry. Supe- rior methods are usually obtained great cost time and money. But since the problem often concerns vitally needed war material, has been found that foundries usually are quite anxious help one another. short, would appear that in- spect:on the cheapest and most re- liable form insurance procurable foundry profits, but, what more important, protects the quality and quantity castings reaching the armed forces. The ordnance department has streamlined its inspection procedure, without sacrificing quality, cutting facilitate inspection, few simple rules are followed. adhering the following points, the foundry should suffer interference with its production schedule through inspec- tion. The points bear mind are: (1) Copies the order should for- warded the ordnance district the prime contractor. (2) The foundry should have these details: [a] blueprints [b] specifications proper test bar patterns (3) Contact the prime contractor for approval changes pattern casting. (4) Notify the local ordnance office sufficiently advance for inspec- tion. Whether inspection conducted the source destination mined when the ordnance district re- ceives copies the purchase order. most feasible the source, the foundry notified that effect. Mere receipt pattern does not prove that dimensional requirements are fully met. blueprint required for all castings produced mounted patterns. Facilities for lay- ing-out the work should supplied Fig. 3—Shrink cracks casting similar that shown Fig. ex from jolt, chine previ All type tio sta wr wi na more and the has dure, tape, imple indry its are: for- strict these for ttern office spec- leter- re- not nents uired un- plied the foundry. Castings from mounted metal patterns jolt, squeezer similar molding ma- chine may, some cases, approved without print, the pattern has previously been approved and sample castings accepted. Specifications All orders must specify fully the type metal required. When speci- fication sub-divided, the composi- bas ~~ & “ tion number class must also stated. This very important. Fed- eral specifications can obtained writing the Superintendent Documents, Government Office, Washington, Ordnance specifications may obtained writing the Office Chief Ord- nance, War Department, Washington, for copy, the foundry may get touch with the local ordnance district, which will arrange supply copy. must stressed that the foun- dry should obtain copy the Fed- eral specification and adhere it. Type scrap and analysis mate- rials given the specification de- termined those expert that type material. some cases im- possible achieve physical character- istics without rigidly adhering the Every foundry should also have copy Federal specification QQM- addition the specification covering the product question. Specification deals with inspection metals. non-ferrous foundries the prob- lem specifications simplified the general use ingots speci- fied composition. course, revert added the mix, but since this presumably known composition should not prove problem. Conse- quently, very few rejections are due incorrect analysis. The few rejects encountered are usually due such obvious causes zine flare con- tamination. Physical failures are more prevalent, however, and are commonly caused poor melting and pouring practice, incorrectly made test bars. shows normal iron particle distri- bution manganese bronze. Micro- graph the right shows bad case iron particle segregation. Both specimens not etched, magnification 100 diameters. greater number chemical re- jections are made steel. Here analysis depends entirely foundry control. This must exercised even after careful selection raw mate- rials. electric furnaces, bridging excessively sluggish slag will often result analysis. Many foundries check before pouring offset this. Lack cupola control may result hot and cold converter blasts, lead- ing later difficulties. Cupola con- trol can easily checked wedge chill test each ladle, before transferring the converter. Gray iron usually specified physical basis only, and rejected for low physicals. The physicals can raised lowering the carbon both carbon and silicon. Late addi- tions graphitizer will produce enhanced physicals. plus Test Bars the test piece not attached coupon integral part the casting, necessary have cor- rectly designed test bar. Suitable bars and molding techniques are illus- trated Federal specification QQM- where special test patterns are neces- sary, they are illustrated the indi- vidual specification. The number test bars required determined the customer, the inspector, the specification. The .expense test bars should included the quota- tion, the foundry must pay for these tests, unless otherwise stated the contract. metallagraphic test required, the foundry should supplied with standard micrograph, illustrating suitable structure. When possible the entire cross section will taken. other cases the inspector will choose part parts. Good judgment must used order select samples representing the entire casting, due the possibility excessive segrega- tion certain parts, illustrated Fig. ferrous material, where certain characteristics such struc- ture steel, primary graphite pearlitic malleable are looked for, standard micrograph may not re- quired. the foundry not equip- ped for this work, permissible have done suitable outside source, When X-ray tests are specified they are usually establish correct molding technique. accomplishing THE IRON AGE, April 22, 1943—43 | ke fet = ° ° ° : 7 = elimi- this the X-ray test either nated used only occasional check. This work too, may done outside source. tests are required, the foundry should equipment, unless other arrangements suitable the ordnance department are made. Although not often speci- fied, etch tests are very helpful determining the cause This, course, assists the foundry preventing future rejects. Major defects visual inspection are due shrinkage and sand con- trol. view the fact that rejec- tions due poor sand conditions are quite prevalent, particularly steel, the “Casting Defect Chart” accom- panying this article may prove help- ful overcoming some these re- (Direct causes are CAPITAL indirect causes lower case BLOW DROP HOT CASTING CRACKS 44—THE IRON AGE, April 22, 1943 Note: Fines are sand grains retained 200 mesh, 270 mesh, jects. This chart was compiled the Dietert Co. Welding Without specific permission from the inspector, defects must not welded. The prime contractor has authority issue this permission. Any unauthorized welds are subject immediate rejection, since the in- spector has way knowing what lies below the weld. certain specifications cannot met, but the foundry product satisfactory, written permis- sion must obtained from the prime contractor waive one specification favor another. The ordnance department should not contacted matter this type. suitable, the prime contractor will obtain per- mission use new specification and forward it, writing, the foundry, This also true for any pattern changes the foundry deems advisable. The foundry will have difficulty delay, due ordnance inspection, the previously listed points are adhered to. The foundry should re- member sufficiently advance, and state the day and time spector needed witness pour- ing. The inspector will there, and, necessary, lay out program that will fall into the foundry’s pro- duction schedule. The possible causes and cures for rejections listed this discussion are merely examples what found true some cases and are not intended authoritative solutions highly controversial questions. Casting Defect Chart increase clay mixing ramming and pan. Increase Increase additions additions fines reduce reduce reduce moisture high clay high additions grain Ss size | nt Low reduce nes fines, high moisture Increase hardness additions size moisture control Increase mixing, LOW moisture, sea coal reduce reduce clay plastic increase Increase moisture coarse and bond LOW ramming additions grains ay, a coarse METAL rains PENETRA- mesh reduce plastic bond, moisture PIN reduce reduce size RAT reduce reduce fines, grain (Sand) reduce clay grain sizo additions cut and ittern sable. iculty ction, are pour- and, gram pro- for are been not reduce dditions Co. BARMASEL tests that magnesium has excellent resis- tance corrosion under normal atmospheric conditions. Corrosion speeded, however, climates sur- roundings having higher-than-average humidity and temperature, and mag- nesium alloys need surface protection where such conditions prevail, the tropics and semi-tropics. Salt seaboard air may also increase the rate corrosion. many applications, therefore, and particularly aircraft, magnesium alloy parts should protected with suitable coatings that withstand exposure severe atmos- conditions. general, the coating procedure consists four es- sential steps: Surface cleaning, chemi- cal treatment the surface, priming and painting. Failure achieve absolutely clean surfaces the metal parts chemically treated will almost cer- tainly result unsatisfactory service and early failure the protective coating, even approved procedures are otherwise faithfully followed. Complete removal all foreign sub- stances essential, not only dirt and oil, but oxides and other impuri- ties. The chemical coating ap- plied the second step must come contact with nothing but the metal- lie surface itself. easy way test whether not magnesium surface properly clean dip cold water. If, upon removal from the water, the metallic surface entirely covered film water, then the surface clean. But there any break the water film, certain that foreign matter still the metal. Surface Protection Since the resistance magnesium corrosion lowered climates high humidity and temperature, essential that the surfaces well protected. Herein, the author describes several methods chemically preparing surfaces prior painting and evaluates them with respect the alloy treated. What paints use primer and finishing coats also discussed. Any the well known methods solvent alkali cleaning may used degrease magnesium surfaces, but cleaners the strongly alkaline variety are considered best. Alkaline cleaning may accomplished either lytic process the alkaline solution. The following solution recommend- satisfactory: Tri-sodium phosphate....... Sodium carbonate .......... This solution should kept temperature between 194 deg. and 212 deg. when use. Some means agitation should employed dip cleaning the bath below the boil- ing point. The time necessary in- sure good cleaning jobs will vary between and min., depending upon the type grease that must re- moved. The solution may used without agitation and temperatures below the boiling point the electrolytic cleaning process, the necessary mo- tion being provided gas evolution. The magnesium object cleaned becomes the cathode, and direct cur- rent amp. per sq. ft. suriace the metal adequate. Elec- trolytic cieaning saves time, takes only min. for degreasing. Solvent cleaning may necessary before alkaline cleaning cases where heavy films oil and grease cover the magnesium surface. important, however, that some form alkaline cleaning used fol- low-up step. Gasoline, triclorethylene, naphtha and carbon tetrachloride are good solvents. Alkaline cleaning solutions contain- ing soap have been found satisfactory, but should not used unless the magnesium surface being cleaned subsequently receive dichromate surface treatment. cleaning sur- faces that have been previously di- chromated, soap-free cleaning sub- stances should used. Otherwise any soap adhering the surface will Economic Aspects Metal Cleaning and Finishing THE IRON AGE, April 22, educe crease Crease > ate adversely affect the adhesion paint films the metal. was indicated the beginning this article, magnesium alloys have good resistance corrosion when ex- posed atmospheres free salt and neither too hot nor too humid, gradu- ally darkening thin oxide film formed. This oxide film inclined retard subsequent attack. Some the alloys, fact, are more resistant sea air and salt spray than others, but general all alloys should further protected when exposure saline solutions expected. The fol- lowing are the most important meth- ods providing chemical surface pro- Chrome-Pickle Treatment: Otherwise known the acid dichromate dip, the chrome pickle treatment the one most often used protect magnesium parts during storage, shipment, mach- ining joining. produces the well- appearance magnesium products commerce. Application the chrome pickle ping the magnesium part solution made follows: Sodium dichromate ..... 1.5 Concentrated nitric acid. 1.5 pints make one gal. this solution room temperature, evaporation thus reduced and con- centration the solution remains un- changed. desirable for any reason speed the reaction, however. the solution may. heated high 150 deg. Depending the age the solu- tion, parts being dipped should left anywhere from sec. min. The exact time should de- termined trial. After removal from the solution, parts should then al- lowed drain for sec., rinsed cold water, and immersed heated water (about 180 deg. F.). The rinse hot water promotes quick drying the metal. the time dipping has been cor- rect, the magnesium will have yel- red-yellow iridescent hue, the intensity the color depending upon the composition and heat treatment the alloy well upon the age the solution used. some areas not appear have sufficient coat- ing and the general color pale, dip- ping time should increased. HNO: Revives Solution The dipping solution weakens after treatment number articles, and dip min., for example, will longer produce the desired color the surface the metal. The solu- 44B—THE IRON AGE, April 22, 1943 tion may revived this stage the addition nitric acid. pos- sible revive the solution about five times before discarding the batch “worn whole The make-up the solution should controlled analytic specific gravity tests when large quantities magnesium parts are being treated. Parts too large for immersion regu- lar tanks may brushed swabbed with fresh dichromating solution and then washed thoroughly with water. certain amount metal re- moved from the surface magnesi- the chrome-pickle treatment, proportionate the acid concentra- tion, the time immersion and the temperature. Under certain conditions this loss may amount much 0.001 in. and, since change this nature cannot toler- ated accurately machined parts. other surface treatments should used for such applications. Dichromate: The resistance mag- nesium alloys salt water con- siderably increased the metal parts are simply boiled solution sodi- dichromate. has been found that dip hydrofluoric acid before boiling dichromate solution adds the protective character the treatment. This process the most widely used finish-machined parts, dimensional change results. After proper cleaning, the parts should dipped for min. (at room temperature) aqueous solution containing per cent hydro- acid weight, then washed thoroughly running water. They should then boiled for least min. water solution containing per cent sodium dichromate potassium dichromate (by weight). followed washing cold water, then hot water. The dichromate treat- ment outlined should not used with magnesium-manganese allovs, but applicable alloys containing alumi- num and Galvanic Anodize: This treatment recommended for coating magnesium- manganese alloys, but may used satisfactorily with all alloys mag- nesium. Essentially modifica- tion the acid-alkali- chromate treatment. produces uniform black coating and makes good paint base, well providing splendid protection against saline at- tacks. The cleaned parts are per cent hydrofluoric acid room temperature, then removed and wash- cold water. Next they are im- mersed iron steel tank con- taining the same bath material em- ployed the chromate treat- ment (see below). The tank should not allowed come contact with the magnesium parts, but they should connected electrically tank serving the cathode and the mag- nesium the anode. For each square foot anode area current density amp. more should main- tained. current more than amp. per sq. ft. should avoided else powdery coating will form- the metal. This treatment should permitted continue for min., depend- ing upon the amount current and the temperature prevailing. the solution temperature increased 150 deg. F., the time needed for the treatment will reduced. Alkali-Chromate Treatment: Although this treatment has largely been super- seded the dichromate treatment, mentioned here because quite satisfactory when used magnesium products which have been machined fine tolerances since causes little dimensional change. Following thorough degreasing and cleaning the parts, three steps are involved. The parts should dipped water solution containing per hydrofluoric acid* for min. (at room temperature), then washed thor- oughly cold running water. Next. the parts are boiled for min. longer water solution contain- ing: solution prepared diluting per cent hydrofluoric acid with two volumes water. Ammonium sulphate (weight). Sodium dichromate (weight). Ammonia (sp. gr. 0.880).. 0.25% (weight). Water added when necessary replace the loss evaporation dur- ing the boiling operation. After this step, the parts are washed cold running water once more. Third, the parts are boiled for five more minutes water solution containing per cent arsenious oxide weight, the solution having been prepared adding 1.33 oz. arsenious oxide for each gallon water. Again, must remembered add water replace that which boils away. Finally the parts are washed cold running water, then dipped hot water. The coating resulting treatment black dark brown, ac- cording the composition the alloy I x em- eat- vith ould lag- lare sity ain- rm- tted end- and the the per- ined ittle ving wo dur- this cold five ution nious vhich are then this ac- alloy and the condition the solution the second step. Chrome-Sulphate Treatment: Where resistance the treatment kept low, the sulphate treatment usually indicated. can applied all commercial magnesium alloys except The solution used contains oz. mag- nesium sulphate and oz. sodium dichromate per gallon water. Parts should immersed for min. temperature 160 deg. Absolute cleanliness the parts vital the success this treatment. should remembered that this treatment recommended for one specific purpose, and that does not provide satis- factory paint base the dichro- mate treatment several other methods chemical surface protec- tion. Chrome-Alum Treatment: This treat- ment provides die castings mag- nesium with decorative black finish which good paint base. Parts min. (long enough obtain the de- sired black color) boiling water containing oz. potassium chrome-alum and oz. sodium di- chromate per gal. more uniform coating will result the die-cast sur- face film first removed machin- ing, sanding, brushing buffing. should remembered that when high resistance salt water corro- sion needed, the acid- dichromate treatment will give better protection treatment. chrome alum Extensive tests have been made surfaces treated the various meth- ods described above determine their comparative qualities bases for paint coatings. These tests have shown the following the best surface treatments for mag- nesium-base alloys containing alumi- num, and manganese: The di- chromate treatment; the di- chromate treatment, and the galvanic- anodizing treatment. For magnesium-manganese the chrome-pickle and galvanic-anod- izing treatments are best. The chrome- pickle and chrome-sulphate treatments are recommended when electrical re- sistance the treated surface must Painting Systems naturally appear give the best pro- tection alloys primarily freshly dichromated magnesium parts out the tank containing water solution per cent sodium potassium dichromate. This treatment followed washing cold and then hot water. ° paint applied the same manner all cases. obvious that mag- nesium applications which are likely subjected corrosive and ad- verse atmospheric conditions should receive the greatest protection pos- sible. The use chemical elec- trochemical surface treatment com- bination with paint coatings will pro- vide such protection. The priming coat paint for sur- face-treated magnesium parts should chosen because adhesive quality. corrosion properties, and resistance Adhesion the most important factor however. Many primer pigments have been tested, and considered, only zine chromate has shown good ° corrosion-inhibiting properties. Thus should constitute all the primer’s pigment content. Certain the synthetic resin var- nishes are excellent primer vehicles with respect adhesion and moisture exclusion. The P27 chromate type primer highly recommended. Varnishes made with 100 per cent phenolic resins and moderate oil length are best suited for use sur- faces which will come contact with salt water. finishing coats, the actual service conditions anticipated should determine the number needed pro- tect magnesium alloys properly. For severe conditions, three finishing coats addition the priming coat are THE IRON AGE, April 22, 1943—44C 7 required for proper protection. This four-coat system. The resistance moisture penetra- tion perhaps the most important characteristic sought the paint for finish coating. Such resist- ance depends upon both the pigment New System STUD locking system which can adapted any func- tion performed ordinary studs threaded inserts soft materials like the light alloys wood has been developed Jose Rosan Hollywood, Cal. The units comprising this system are manufactured under license Bardwell McAlister, Inc. simple ring with serrations inside and out into place over in- terlocking serrations built into the stud head, making tight fit flush with the surface the material which used. The stud differs from ordinary stud that has central collar equipped with teeth. the serration flush with slightly = OSE ROSAN, inventor the new locking system, shown explaining the action serrated rings steel insert. This locking system adapted any function performed ordinary studs and threaded inserts. 44D—THE IRON AGE, April 22, 1943 and the vehicle used. Tests have con- clusively proved that aluminum paint can made with higher moisture im- pedance than any other paint, and ex- cellent results are obtained with ratio lb. standard aluminum paste per gal. vehicle. For finishing coats, phenolic resin below the surface the material. The ring then falls into place, and with special tool short length bar steel bored clear the stud, the operator drives the ring into the countersunk hole prepared ceive it. Use the ring intended pre- vent the stud insert from turning its location. accomplish this, the ring fitted along its outer pe- riphery with V-shaped splines. When seated either hard soft material, these splines, broaching their way into the material, act hold the ring and, through the rangement with the mating part, hold the insert stud firmly place. Installation the insert made with threaded tool and lock nut and driving tool with which force the ring place. Operations for installa- tion may done manually with power. the absence the special tool, installations may made using ordinary bolt and nut screw the insert into position and using hammer drive the lock- ing ring. Removal the insert accomplished drilling depth equal that the serrations be- tween the ring and insert. Then the insert lifted with special tool. Rings are made from SAE X1112 screw stock. Inserts and studs also may cut from free cutting screw steel, chrome moly steel bronze. insure accuracy fit, the ring di- ameter held within tolerances +0.002 and —0.001. Clearance be- tween the inside the ring and out- side the collar varies from 0.006 up, depending upon the insert’s size. Locking action the ring and its mating parts, which prevents studs and inserts from unscrewing under variety conditions, accom- plished combination several engineering principles. spline action the basis for its positive lock, and number splines ser- rations are located the insert stud locked. varnish vehicles are best. Varnishes short oil have superior protective properties longer oil varnishes. Highly satisfactory results have been obtained with aluminum pigment 20-gal., 100 per cent phenolic resin varnish containing about one-fourth linseed oil and three-fourths tung oil. for Locking Studs and Inserts Tests various aircraft plants have shown these inserts are capable withstanding the desired loads materials such plywood, solid wood, phenolic plastics, translucent plastics, micarta, aluminum, alumi- num alloy and magnesium alloy. Both inserts and studs may used fasten clamps jigs and fixtures built wood masonite. This means locking can also adapted such applications drill bushings, spark plugs, plugging holes and elec- tric terminals. NSTALLATION studs and in- serts easily accomplished (right) plexi-glass shows. With spe- cial tool, locking ring being ham- mered into place around insert head. Procedure the same for wood and metal. locking ring shown the left. | hes een sin rth oil. steel casting industry outstanding example in- dustry abruptly forced from its ordinary peacetime position one where the demands upon are far excess the available production capacity. For many years the Saginaw Malle- able Iron Division General Motors Corp., the world’s largest producer malleable castings, has been en- gaged the production malleable iron for automotive use, and, more recently, the making “Arma- Steel” castings which have found ceptance replacement for certain types steel forgings and bar stock. First technical description Arma- May 25, 1939. Anticipating increased demand for malleable and ucts, this company decided early 1941 substantially increase the productive capacity the plant. This expansion program was nearly com- pleted the time war was forced upon Japan. The entrance into the war completely altered the nature the demands the country was place the iron and steel industry. careful survey revealed that was very doubtful the requirements for JAMES SMITH General Manager, Saginaw Malleable Iron Division, General Motors Corp., Saginaw, Mich. The story the conversion the world's largest producer malleable castings the production steel castings continu- ous basis order better serve the war effort told detail this article. Some the equipment and many the methods dis- cussed herein are most unusual steel foundry practice and should prove great interest plants already producing steel castings, well plants planning undertake such work. war work would completely utilize the company’s expanded malleable facil- ities and the same time was becoming increasingly obvious that the existing steel casting production capacity would woefully inade- quate meet the accelerated de- mands the war. This picture led consideration the possibility putting use the company’s idle capacity start- ing the production steel castings. The fact that many the steel cast- ings required for war purposes were nature adaptable volume pro- foundry influenced the decision con- siderably. Frankly facing the fact that the entire history Saginaw Malleable’s operation has been the volume pro- duction small castings, that the “know-how” the personnel and the nature plant facilities are built around this type operation, was decided start making steel castings, but within the boundries firm management policies that took full cognizance these facts. 1942, the necessary priorities were obtained enable the purchase additional equipment needed complement existing facil- ities for tentative production ca- pacity approximately 2500 tons steel castings per month. The first experimental steel heat was poured March 1942, and the latter part March production castings were moving into the finishing de- partments steadily increasing numbers. the end October tentative goal had been surpassed with the production for that month alone slightly excess 2700 tons. None the personnel had past experience with cast-steel and only one experienced steel man, melter, was added the organization. How- ever, thorough training efficient handling methods stood good stead and speedy and successful conver- THE IRON AGE, April 22, ngs, in- | this ert pe- m- ad. ind the sion steel production was affected. Blunders were made, but some the company’s ideas proved out and have resulted methods manufac- ture considered revolutionary steel foundry practice and have affected substantial savings man-hours, improved metallurgical control and entirely satisfactory product. The methods used are really nothing en- tirely new however; they have been used for some years making malle- able castings. conform the company’s mechanical facilities and perience the organization, the com- pany contracted make only steel castings weight classification not lb. Although steel castings are com- monly made several classes chemical and physical properties, seemed desirable concentrate efforts one two classes steel the volume the demand those cate- gories was sufficient permit speciali- zation. The huge quantities war demand for certain castings with high physical properties lent new life the idea volume production set-up. Also the production this steel entailed the use considerable heat-treating capacity and, the forecast war requirements showed definite limita- tions the use malleable iron, sufficient amount equipment was available handle the contemplated steel pro- gram 2500 tons month. submit the pertinent facts with- out further elaboration, the company present producing manganese, copper, molybdenum steel. The work consists few jobs required very large quantities several parts scheduled fairly small lots. The high production parts, course, make the bulk the tonnage. Anticipating the comment that the mechanized set-up made possible only the grace unusual war 46—THE IRON AGE, April 22, 1943 charging the electric furnace. dotted lines shows chute idle position. ° ° demands which permit specialization, freely admitted that current pro- duction type not commonly found the steel casting industry prior Pearl Harbor. However, these two facts should kept mind. First: The com- pany’s decision make steel was hedged the provision that would stick the methods that had been wisely matched with improved manu- facturing methods improved metallurgical control resulting lower-cost, higher-quality product, can much break down the tradi- tional antipathy toward steel castings and bring consideration possible use fields heretofore con- ceded other materials other forms steel. The melting department the plant occupies only about 7800 sq. ft. floor space and equipped with two large and one small acid cold- melt electric furnaces. The entire foundry layout keyed the idea continuous, synchronized operations and basic factor maintaining this continuity the furnaces are fired and tapped rotation, thus deliver- ing uninterrupted supply molten steel the pouring section the mold conveyor. Normal 24-hr. opera- tion yields approximately 200 tons 8-ton heats from the large furnaces and heats from the small furnace. No.3 Furnace Furnace used successfully making malleable iron and which were thoroughly un- derstood, contrast the conven- tional steel-foundry set-up which was quite foreign the company. Second: The picture the steel casting in- dustry prior the war does not necessarily form set pattern which cannot changed and improved when peace comes again. The accelerated pace steel cast- Transformer 2—Floor plan the furnace and charging system. Since sulphur phosphorous can eliminated the acid electric process, the control the steel must start with the materials charged inio the furnace. order keep these two elements minimum, and also avoid excessive amounts residual alloys which might affect the physical properties, all incoming steel scrap for melting unloaded piles ac- cording its analysis. The charges are made using specific amounts burning bench ing production during the war, Casting v7 3—System for handling sprues. From the scale, the charging box will Fig. rolls Sprue t rous MUST these also idual scrap from the various piles according charge sheet made out the metal- lurgist. After melting down each charge the electric furnace, sample the metal poured just prior the boil. This sample later analyzed for carbon and manganese and serves guide keep the melt-down car- Following the boil, mold. After chilling, this sample placed the Carbanalyzer (an elec- for determining carbon content) and the carbon read- ing obtained matter seconds. This operation, which each melter must perform himself, gives the neces- sary information finish the heat without delay. Another sample poured from the same cup steel later analyzed for carbon and the laboratory. sample the finished steel taken for complete chemical analysis after the bull ladle approximately half emptied. The slugs from which test bars are turned are also poured this time. All the above analyses are complete mately hr. after tapping the heat. study has been made finish slags and their relation metal con- trol. result, each melter re- quired pour sample pancake slag each his heats just prior tapping out. These samples are brought the laboratory along with the steel samples and are checked for color and general appearance further means maintaining con- trol. Periodic analyses are made the slags absolute check color and appearance. Quenching and drawing cycles and temperatures and checked the laboratory. Sample castings are tested regularly from the draw furnaces throughout the day assure correct Brinell hard- ness. Samples are taken periodically for microscopic inspection the structure insure that the Gamma-ray radiography used ex- tensively means developing 4—Handling molten steel. Steel held the 5-ton bull ladles shown photo right for feeding the covered teapot ladles. Molds are poured from this teapot ladle moving con- veyor. gating castings. technique insure sound Charging Procedure The charge materials, consisting shop steel scrap, sprues, bushling, bundles and briquettes, are present loaded from the floor into 22- in. cradled dump boxes mounted skids. each box loaded moved electric truck loading station set scales. After weighing, each loaded box moved electric truck from the the furnace floor and raised electric hoist monorail above elevated charging platform. The charges are loaded during the melt- ing time, consequently complete charges for each furnace are stored the monorail, which runs the en- tire length the furnace floor. The mechanical operation the furnace charging setup shown diagrammatically Fig. and Fig shows the charging chute both the idle and charging position, while Fig. the overall plan the charging system. Each box the charge (three nine boxes) moved along the mono- rail and dumped the chute. the charging progresses the furnace may lowered and the chute backed out distribute the charge evenly from front back. The flaring design the end the chute serves force the material the sides the furnace and eliminate any tendency the material pile and plug the chute. The charging having been com- pleted, the empty boxes are lowered the furnace floor electric hoist, picked electric truck, and re- turned their respective loading sta- tions refilled. Side charging furnaces are gen- erally considered inefficient because the time required charge them. However, the efficiency the sys- tem outlined here evidenced average charge time min. per eight-ton charge. Plans have been drawn and construction begun new system handling and loading sprues, which constitute approximately per cent the total charge. This layout shown diagrammatically Fig. With this layout, sprues will raked into the boxes from elevated chutes, which originate disposal bins for the sprue burners working overhead platform. Gravity rolis will serve convey the boxes under the chutes. each box filled will moved down the rolls the scales, and from this point the THE IRON AGE, April 22, 1943—47 a an di- eir on- the ith ire | cycle will the same the present system previously described. Five-ton bull ladles, handled overhead crane, serve transport the molten steel from the furnaces bull ladles steel the station one time, since two ladles per heat are tapped from the large furnace and the heat from the small furnace replaces one ladle large heat. 5—Top photo shows the hot casting hook-up station where castings, after shake- out, are loaded the moving conveyor. Lower view shows the green casting inspec- tion and sorting conveyor. the holding station where the pour- ing ladles are filled. each heat tapped, moved directly the holding station and placed one three stationary cradle standards from which the pouring ladles are serviced. general rule there are two 48—THE IRON AGE, April 22, 1943 Pouring Molds Steel poured into the molds from covered teapot ladles, which are carried electric hoists shaped monorail loop. mov- ing pouring floor ft. in. long plate mold conveyor facilitates con- tinuous and efficient pouring. shows this pouring set-up. Fig. When the pouring ladle emptied moved the monorail the holding station refilled from 5-ton full ladle. each empty ladle moved away from the conveyor full ladle replaces the head the conveyor. Possibly one the lems steel foundry that melts acidic high-manganese steel that maintaining long life ladle lin- note that average 100 heats per lining obtained with the pre- viously described bull ladles and nine heats per lining with the pouring ladles. Both type ladles are lined with sized Western ganister and mixture silica, alumina and iron oxide. The molds are made automatic jolt and squeeze, pattern stripper type moldings machines. Ten machines (five drag and five cope) are located line outside and along one side the loop oval-shaped endless, power-driven plate mold conveyor. The drag halves the molds are placed the conveyor and moved constant speed down slight in- cline past the cope machines. The purpose the i