The Iron Age 1944-10-05: Vol 154 Iss 14

1944 COMPLETE STORY PAGE — j | More horsepower per dollar! With the new Cleveland Speedaire Worm Gear Unit possible obtain operat- ing capacity equal that standard worm gear unit having approximately double the frame size. continually removes heat means high-velocity air stream scouring the outer surfaces the oil reservoir, giving greatly-increased capacity over standard worm gear unit. You can apply modern, right-angle Speedaire Units many kinds equip- ment where you have used other types heretofore. Plan install this modern Drive Unit your machines. Send for the Speedaire Catalog today. The Cleveland Worm Gear Company, 3252 East 80th St., Cleveland Ohio. Affiliate: The Farval Corporation, 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. 154, No. 14. ASE wa ~ — | | 3 ~ ‘ , e VAN DEVENTER General Manager Vol. 154, No. October 1944 Editorial and Advertising Offices East 42nd St., New York N.Y., Editorial British View Lend-Lease Hayes, Production Manager, Baur, Typography and Layout Regional Business Managers Technical Articles 100 42nd St. East 42nd Half-Strength Centrifugal Castings hilton 1134 Otis PEIRCE Heat Treating 5-In. Navy Shells RAYMOND KAY Iron and Steel Engineers Meeting Los Angeles 2420 Cheremoya Ave. New Equipment ° ° ° Owned and Published COMPANY Features Gepyright. 1944, by Chilten Company ms é News Front Chestnut ond Séth Sts. West OFFICERS AND DIRECTORS Fatigue Cracks Steel Wage 103 ypes August Pig Iron Output........ 102 dern Member, Audit Aluminum 105 Copper Prospects X-Day.... 116 Technical Course for Latin America 118 Member, Business Peru Build Steel 122 Postwar International Meeting 126 Machine Tool Market Developments 148 Non-Ferrous Metals News and Prices 150-151 Iron and Steel Scrap News and Prices 152-153 the Arts Comparison Prices Week and Year 154 Single Copy, cents. Warehouse, Semi-Finished, Tool Steel Prices 158-159 Steel Pipe, Tubing, Wire Products, Prices 160-161 A President 3 All steps for providing hardenability data will demonstrated NATIONAL METAL CONGRESS CLEVELAND OCTOBER 16-20 BOOTH Booth 141-B the National Metal Congress, Ryerson plans conduct Jominy End-Quench Hardenability Tests and explain how harden- ability results can interpreted terms phys- ical properties for quenched and drawn alloy bars various sizes. you attend the show, don’t miss this unique Ryerson display. Ryerson has always exercised close control over alloy steel quality, and for number years has furnished the chemical analysis and heat treatment response data with each alloy shipment. Now, this service has been extended under the Certified Steel Plan give new added hardenability information, which makes Ryerson service even more helpful than before. new type report, containing both harden- ability and analysis data, now being sent with each Ryerson alloy steel shipment. addition the chemical analysis, every heat alloy destined for Ryerson stocks subjected series end- quench tests. The results these tests are inter- preted through tables known physical rela- tionships reveal obtainable tensile strength, yield point, elongation, and reduction area for bars inches diameter, that have been quenched and drawn 1000°, 1100° and 1200° The Ryerson Alloy Steel Report includes all this test data plus recommendation working temperatures. Whether you order single bar many tons, you are assured report covering all alloys shipped. All Ryerson alloys are identified with color markings according type steel. Large bars are individually stamped, smaller bars are bundled and tagged with unmistakable heat symbol. The identification cross referenced between steel and report sheet that any steel can quickly verified. Investigate! Make sure you are getting this important help. JOSEPH RYERSON SON, INC. PITTSBURGH Steel-Service Plants: 48—THE IRON AGE, October 1944 MILWAUKEE PHILADELPHIA BUFFALO ST. CINCINNATI NEW YORK BOSTON TON ESTABLISHED ° ° Oct. 1944 VAN DEVENTER President and Editorial Director BAUR Vice-President and General Manager ° DIX Manager, Reader Service ° ° Editorial Staff Technical Editor ........ OLIVER Commercial Editor, CAMPBELL ° Associate Editors WINTERS TRUNDLE ALBIN JOHN ANTHONY BARMASEL Editorial Assistants SCHIEN WILLIAMS VAN CAMP MUNZER O'CONNOR MILLER Regional News and Technical Editors LLOYD Pittsburgh 428 Park Bidg. POST Chicago 1134 Otis MOFFETT DONALD BROWNE EUGENE HARDY Washington National Press BRAMS Detroit 7310 Woodward Ave. OSGOOD MURDOCK San Francisco 1355 Market St. Editorial Correspondents ROBERT DEAN Buffalo FRAZAR Boston HUGH SHARP Milwaukee SANDERSON Toronto, Ont. RAYMOND KAY Les Angeles JOHN McCUNE Birmingham ROY EDMONDS St. Louis JAMES DOUGLAS The British View Lend-Lease (Cabled from London) steel workers are complaining that heavy importations American semi-finished steel under lend-lease arrangements are continuing time when the steel rate the United Kingdom drop- ping. Concomitant with easing manpower situation, this complaint understandable. can well imagine similar objection being even more loudly regis- tered our American steel workers the situation were reversed, and the face declining labor market home, several hundred thousand tons steel month were coming into the United States from abroad. This lend-lease business, after the war, likely become inter- national hot potato unless realistically approached and viewed solely war measure and not postwar practicality. “in kind” payments were made for practically all lend-lease exports our Allies except, course, the specialized munitions and war equipment not applicable normal trade, the same objections would arise would our postwar receipt steel imports. The continuance the importation semi-finished steel Britain was and war measure although has not been realized the steel workers. British railways have been called upon tremen- dous job since the June invasion due, the main, the require- ments troop movement and supply. And from the transportation standpoint, the importation ton semi-finished steel saves the domestic hauling least two tons ore, limestone and coal. England, unlike America, normally must depend upon imports and exports. Now, after five years completely dislocated trade economy, that country the position shopkeeper who has for long time been cut off from both suppliers and paying customers. Her shelves are bare and the cash register has ceased ringing. Although look for- ward doing profitable business with the British Empire after the war, must kept mind that England will position become regular customer, nor supplier, until regains its own customers. Under the terms lend-lease, Great Britain prohibited from using American steel and other goods for developing exports. the face impending easing war manpower, inevitable that the British will seek postwar clarification lend-lease, and from the stand- point mutual interests, both postwar trade and security, should seek also. 7 la- th, for his ns, rge INLAND STEEL for Victory and for Peace Inland metallurgists and steelmakers are developing new steels and improved processing methods that are helping speed the day Victory. These developments, and those that are come, will assure the finer and more durable products for America Peace... and remember Inland specialists are ready help you with problems selection, design fabrication. following summary Inland products for your convenience. Cold Rolled Sheets and Sirip Plates, Shapes and Bars Inland rolls wide range high quality cold rolled sheets Inland produces plates and shapes all standard specifica- and strip for many manufacturing purposes. The charac- tions wide range sizes and weights and bars hot teristics are varied meet the exacting requirements rolled carbon, carbon spring steel, every product and method fabrication including forming, spring steel qualities. deep drawing, spinning, etc. Steel Sheet Piling Hot Rolled Sheets and Strip The nine different piling sections rolled Inland meet ble practically all construction requirements. This piling advancements rolled from especially tough steel with tensile strength essing and finishing operations have been pioneered excess 70,000 The Inland interlock permits free Inland—resu!ting hot rolled sheets and strip that are driving, yet remains watertight. unsurpassed for workability and finish. Hi-Bond Reinforcing Bars eets Hi-Bond Bars made Inland represent the first real im- Inland offers many types galvanized sheets for roofing, provement the bonding value reinforcing bars more siding, and many manufactured products—some are made than years. The scientific design this new Inland for moderate drawing and bending, and Paint-Tite sheets bar, strength. Hi-Bond Bars are made nine standard areas. Tin Mill Products Rail and Track Accessories Inland rolls standard rail sections ranging from Inland produces tin plate both the hot dip and electro- ASCE 131 Ibs. R.E. For the past nine years including lytic methods. Coatings are uniform and lustrous, suitable the heavy wartime traffic, transverse fissure has been for containers and many other products. Inland also pro- found laboratory examination rail which has been duces manufacturing terne and tin black plate control cooled Inland. Joint bars, tie plates, track belts various finishes. and spikes complete the railroad service. 4-Way Floor Plate Special Steels for Special Purposes The exclusive design Inland Safety Floor Plate assures Inland manufactures low alloy, high- 4-way traction, 4-way drainage and sweeping, and 4-way strength, corrosion and abrasion resistant steel that matching. has the structural strength and wearing quali- saves weight without sacrificing strength. ties rolled steel. naturally forms very good floor Ledloy—the lead bearing, faster machining steel—is another Inland alloy. output 110% because safe and cannot burn, warp, splinter, absorb and lengthens tool life 300%. moisture odors. Write for Inland Steel Products Book No. INLAND STEEL COMPANY Dearborn St., Chicago Illinois 50—THE IRON AGE, October 1944 bat cas its eit pro Cor eac ste all pre tri sin ter: are equi desc than Stic News Front October 1944 Washington and New York reporters left the recent press conference the motive Council for War Production with little knowledge how the automotive industry will reconvert and with the definite impression that the automotive people themselves too little knowledge their own needs make any recommendations Some critical sizes shells have flown Europe the last month meet battlefield needs. Recent research centrifugal castings have resulted the development steel castings having tensile strength 180,000 lb. per sq. in. and ductility per cent. new anodic coating for magnesium alloys has been developed for which superiority claimed finishes produced the acid dichromate and chrome pickle treatment its high resistance both corrosion and abrasion and that may produced either alternating direct current. Postwar planners, private and governmental, look for housing major work producer, with some 1,000,000 units constructed yearly for the ten postwar years. Prefabricated wooden houses standard architectural appearance may account for much per cent this total. The purchase Gunnison Housing Corp. Steel Corp. does not indicate revival prefabrication. England, the government plans erect some 100,000 temporary housing units each year for three years. These units, the so-called Portal house, will with components turned out various pressed steel companies. permanent unit, the Weir house, also being considered. The Portal house will absorb about 400,000 tons sheets per year, over twice pre-war consumption sheets the British automobile industry. Studies made prominent research organization indicate that the average im- trial worker has invested $250 war bonds during the past three years. Big business, which general fretted under Government rules and regulations Since war started, pressing for continuance WPB production controls during the reconversion period. reas. WPB, however, intends completely discard the controls any particular terial just soon production exceeds war demands. This plan probably will not altered. Ibs. Machine tool producers, worried about the 500,000 surplus built during the are somewhat startled England's suggestion that shipments returned with provisions. Officials are working plans that this will nov occur. The British Government expects that after the war there will large and urgent from devastated Europe for machinery and machine tools all descriptions. And: plan being formulated that home manufacturers will first re- with new and modern equipment, during which period the older equipment exported, provided was workable condition. RFC now ready issue brochures each its war plants, setting forth description buildings, facilities, and equipment. Buyers can indicate interest arrangements for purchase, that immediate occupancy can follow cessation work. Plans are also well developed enabling private plants indicate desire thase all any portion RFC equipment their plants, with associated arrange= made move undesired equipment into temporary RFC warehouses just soon work stops. Aluminum scrap, currently drug the market, has recently been sold less than ton. aerial bombs Burma are being equipped with nose spikes that they into roadbeds and bridges rather than ricochet. | | h ° Is q q High-Strength Centrifugal Castings brief description some recent research resulting cen- trifugally cast steels having strengths the order 180,000 Ib. per sq. in., and ductility per cent. The author was recently assistant metallurgist Cleveland Pneumatic Tool Co. quest for castings with physical properties equal those wrought forged stock has been long and eagerly sought goal. Today, metallurgists see that task near attainment the lat- est developments centrifugal cast- ings. Steel castings are being made having tensile strength 180,000 Ib. per sq. in. and ductility about per cent. The centrifugal castings-in this research were cast vertically ro- tating iron mold. They were tu- specimens centrifugally cast steel and pierced tubing. Investigation No. cast steel; pierced steel tubing. The upper three rows are normalized and the lower three rows are hardened. IRON AGE, October 1944 ° ° fo} STANLEY PERRY Research Metallurgist, North American Aviation Co., Los Angeles ° ° bular shape, measuring in. O.D., in. wall and in. length. The chemical analysis these castings was similar AISI 4135 and 4140. order compare the physical prop- erties these castings, pierced tub- ing the regular 4140 was selected. All three pieces were normalized, hardened and Table shows the physical properties from specimens taken from each piece tubing. These pieces were oil quenched and heat treated tensile strength 180,000 200,000 lb. per sq. in. Table shows the success achieved this centrifugal casting steel. Sample No. particularly, equal every respect, except for slightly small ductility, the pierced tubing. For other articles centrifugal cast- ing, see THE 22, 1943, 51; April 1943, 52; May 13, 1943; May 20, 1943, pp. 53-64; Oct. 14, 1943, 98; Dec. 1943, 54; Jan. 1944, 110; Jan. 13, 1944, 56. The author has previously had occa- sion test centrifugal castings, but while these castings could heat treated tensile strength 180,- 000 lb. per sq. in. they did not have requisite ductility and the tensile fractures were cast type. Sam- ples Nos. and this investigation, showed fractures ductile materials. Thus, the problem ductility pretty well solved. Aerol shock struts for the landing gear airplanes require able withstand very high shock stresses. The centrifugal castings manufactur- ers are striving make these struts from their product. Heretofore and present, these aerols are made from forgings and pierced tubing. date there one problem which the mak- ers centrifugal castings must salve, that the production tubular cast- ings from ft. long. From Table may seen that sample No. did not quite come the physical properties heat treat- ment. This sample had lower car- bon and manganese (4135) com- pared the other two, which were 4140 steel. .Thus, being heat treated € ¥ CIT an reated together, the lower physicals the former are understandable. not intended cover all the data being developed this research, which going apace. However, several more perti- nent facts may mentioned. The microscopic study the centrifugal castings indicated even dispersion constitu- ents, segregations and greater density material the outer diameter proached. The microstudy in- dicated even dispersion and structure tempered mar- These were produced RIGHT 3—Impact (left) specimens centrif- cast steel and pierced steel tubing. No. Normalized samples the left, and hardened samples the right. Investigation BELOW 3—Impact (left) and fatigue (right) specimens centrif- ugally cast steel and tub- ing. Investigation No. centrifugally cast: pierced tubing. Type Steel Heat Treatment No, Casting AIS! 4135 No, Casting 4140 OIL QUENCHED AND DRAWN TOGETHER No, Wrought Pierced Tubing AIS! 4140 Standard round notched Meore fatigue machines. Strength, Lb. Per Sq. In. Lb. Per Sq. Tensile Strength, 100 145, 200 500 178, 000 definitely are successful encouraging progress cen- trifugal casting for aircraft appli- cations. typical example, aerol struts, wherein centrifugal cast- ings could well used, require with many bosses, lugs and flanges. Should such shapes cen- trifugally cast successfully, the laboratory foundry set up. They laborious boring forgings would eliminated, not mention the making dies and variety machining and welding operations. There are many other applications where cast- ings this quality could fill long felt need. The castings for this research were furnished American Steel Foun- dries, Chicago; and the research was out Cleveland Pneumatic Tool Co. under the direction George Barrett, Jr., chief metal- TABLE Comparison the Mechanical Properties Centrifugally Cast and Wrought Pierced Steel Tubing (Heat treated 180,000 200,000 per sq. in. tensile strength.) Impact Fatigue Bending Hardness Elongation, Reduction Strength, Strength? Pointof Rockwell, Per Cent Area, Notched Per Cent in. Thick Per Cent Ft-Lb. Tensile in. Wide Scale 10.5 36.7 11.5 THE IRON AGE, October qual cast- occa- Sam- ation, ble esses. actur- and com- This finishing process comes close being ideal for magnesium alloys. Two coats paint are sufficient for proper insulation, and high resistance corrosion and abrasion and the decorative value the finish could well have many postwar applications. The chem- icals used are inexpensive, and the electrical equipment not elaborate, since alternating current may.be used entirely. bare mag- nesium al- loys are susceptible cor- rosion under most atmospheric con- tions, they must properly pro- tected prior use aircraft. Like aluminum, magnesium alloys cannot successfully electroplated with non-corrosive metal. Magne- sium differs somewhat from other metals that paint alone will not necessarily form corrosion inhibi- tor, unless the surface the metal has previously been treated with some effective chemical electro-chemical process. Such effective surface fin- ish must not only act conrosion inhibitor itself, but must furnish such paint base that the corrosion inhibit- ing properties the paint are fully utilized. Magnesium alloys are slightly soft- than the other structural alloys, which help during machining, but they are also thus more susceptible mechanical injury. Therefore, the value any surface finish must necessarily measured terms wear, abrasion resistance, well its ability inhibit corrosion. Considerable testing such stand- ard chemical treatments chrome- pickle, acid dichromate, specification AN-M-12, type and revealed that although the finishes gave fair corro- 54—THE IRON AGE, October 1944 SIMPSON Chief Chemist, they and great PAUL CUTTER Research Chemist, Consolidated Aircraft Fort Worth Division offered resistance abrasion and mechanical injury the base metal. fact, some fin- ishes require many four coats paint insure proper insulation; hence, the weight increased. The research en- gineers the Forth Worth Division Consolidated Vultee saw the need for surface finish that would not only offer adequate protection from corro- sion, but would actually shield the relatively soft metal from mechanical injury. produce such finish, the re- search efforts were concentrated developing type effective anodic process, whereby was hoped that the extent the surface finish could compelled the magnesium alloy parts the amount positive cur- rent applied. The natural atmospheric oxidation corrosion products magnesium are carbonates, hydroxides and oxides; all which are highly insoluble and known protective. Therefore, seemed conceivable that effective uniform coating might placed magnesium alloys the use positive (oxidizing) current the presence alkaline solution either hydroxides, oxides combination The initial attempts with alkaline solutions produced anodic coatings magnesium alloys which were 100 times resistant abrasion the acid dichromate finish, but offered advantages over the accepted dichro- mate finish insofar corrosion pro- tection was concerned. Extensive experiments were con- ducted improve the corrosion fac- tor determining the most effective constituents, and their concentration, used the alkaline electrolyte. This search investigated each and all possible combinations the follow- ing: basic forming compounds so- dium and potassium; addi- tives including neutral salts, and acid salts sodium and potassium; or- ganic additives usually the form relatively pure organic compounds, which were stable alkaline solu- tion and contained least one elec- tro-negative polar group direct the otherwise inert molecule the anod- izing surface the magnesium alloy, where could act depolarizer, and some cases become part the finish. Simultaneously, study deter- mine the proper controls was on, type current (AC DC), current density, temperature the electrolyte, and time anodic treatment. Furthermore, experiments were conducted develop after treatment properly neutralize the alkalinity the anodic surface insure good paint adhesion. Since such anodic finishes, although they may appear smooth, are known contain tiny pores which have the power adsorption, study the effect all possible organic and inorganic sealers was made. From this extensive search anod- process was developed which pro- duces finish magnesium alloys | a n v q line 100 the hro- pro- con- fac- tion, all llow- so- addi- acid or- form unds, solu- elec- the anod- alloy, rizer, the deter- ire ments after the hough known UNPAINTED ASRECEIVED ALCLAU 500 HOUR SALT SPRAY CORROSION TEST either alternating direct current that has proved superior Convair the finishes produced the acid- dichromate and chrome-pickle treat- ments, specification AN-M-12, types and resistance both corrosion and abrasion. The application the new process relatively After being properly degreased, the magnesium parts are placed the alkaline electrolyte where they are made the cathode for electro-cleaning with direct current. This removes the manufacturer’s chrome-pickle film and prepares the surface for the 52,000 40,000 strength in. AMC 52S-H, af- ter exposure salt 28,000 spray. 16,000 10,000 DOW7 CVAC-AC CVAC-DC ASRECEWED ANODIZED ONE COAT CHROMATE PRIMER ASRECEWED P DOW7 CVAC-AC CVAC-DC AS RECEIVED ANODIZED AS RECEWED ANODIZED 500 HOURS SALT SPRAY 1G. C.V.A.C. No. chrome-pickle, and acid-dichromate finished magnesium after 500 hr. salt spray. ° ° employed producing the new finish, the current merely reversed, and the work made the anode, the finish desired, the magnesium parts are connected low voltage transformer after electro-cleaning. After anodizing, the parts are rinsed hot water remove excess caustic from the surface the finish. The parts are then immersed warm, weak chromic acid solution for several minutes properly neutralize ONE COAT ALUMINUM LACQUER ASRECEVED CVACAC CAC-DC 500 WOURS SALT SPRAY any remaining alkalinity and brighten the anodic surface. The parts are then dried and sealed dipping them highly-thinned solu- tion chromate primer its equivalent. Since either current may used applying the anodic process, the finishes are known C.V.A.C. No. AC; and No. DC. The current pre- -ferred sheet material and gives smooth, black finish such alloys AMC52S-H and AMC57S and white finish The current produces smooth, green surface AMC52S-H, Prime +Prime Exposure salt spray, days THE IRON AGE, October 1944—55 ption, ssible was pys TEN WEAR REVOLUTIONS HOUR ACCELERATED CORROSION 100 WEAR REVOLUTIONS WEAR REVOLUTIONS FIG. tests for the chrome-pickle finish, and the C.V.A.C. No. and finishes. AMC57-H and slightly more effec- tive castings. Early attempts increase the cor- rosion resistance the new finish over that the acid dichromate met with some degree success the the electrolyte, high temperatures, and alternating current. was then observed that although TABLE Degree Corrosion After 500 Hr. Salt Spray (The first trace corrosion indicated with ascending numbers for the most extensive corrosion observed.) the new finish was very smooth appearance, like all anodic films has adsorption effect. Thus, when any possible non-water soluble material placed the sur- face the anodically finished parts, immediately drawn within the oxidized film. Such material when uniformly applied the C.V.A.C. No. and finishes, greatly Surface Finish Unpainted One Coat Gne Coat Zinc Aluminized Primer AM350......... received........ CVAC CVAC No.1DC.... received........ Dow CVAC CVAC No.1DC.... received CVAC CVAC Anodized.......... ee eee eee 24S-T DURAL..| received........ Anodized.......... NOTE: received magnesium degreased, but still retaining majority the manufacturers’ chrome pickle finish; received aluminum degreased. 56—THE IRON AGE, October 1944 retard the attack salt spray corro- sion and some cases entirely elim- inates it. This increase corrosion resistance the application simi- lar organic sealers was not nearly noticeable with the control finishes chrome-pickle and acid-dichromate. the study the organic sealers, one the most effective materials tried was thin dip coat chromate primer. zinc chromate primer normally applied paint- ing magnesium parts, its use organic sealer was considered most logical. Since the effectiveness any sur- face finish not only based its ability inhibit corrosion itself, but also provide such paint base that the corrosion inhibiting properties the paint are fully utilized, the su- perior corrosion protection derived from the new C.V.A.C. No. and finishes became evident. Salt spray tests were conducted ascertain the effectiveness zinc chromate primer well other paint coating the new finishes compared with chromate-pickle and acid-dichromate. When specimens were given the above finishes and sealed with one coat zinc chromate primer, the C.V.A.C. No. finishes showed progressive corrosion after 500 hr. the salt spray while the chrome-pickle and acid-dichromate failed badly, shown Fig. and recorded Table Further test for 500 hr. salt spray also revealed that two coats paint were sufficient completely seal the new finishes from all sion while many four Q 1 alers, erials omate paint- most sur- its but that ties su- lerived zine other shes and the ith one er, the hr. necessary with the chrome-pickle and acid-dichromate. Since the above findings were based observation, extensive test was conducted which employed sets, each, finished magnesium ten- sile coupons. The tensile specimens were subjected salt spray corrosion from 1320 hr. When the vari- ous sets tensile coupons described Table were pulled and the ulti- mate tensile strength plotted against time the salt spray, was found that the C.V.A.C. No. finished alloys, plus one coat zinc chromate primer retained their ten- sile strength through 1320 hr. while the primed acid-dichromate showed signs weakening much sooner, demonstrated Fig. Corrosion was also checked plac- ing the specimens tested accelerated corrosion bath made the basis grams sodium chlo- ride, per cent hydrogen per- oxide and 180 c.c. distilled water. the attack was expected heavy, the gases given off were col- lected and the degree corrosion de- termined calculating the weight magnesium displaced equivalent the volume hydrogen gas given off corrected standard conditions. This test (unprimed) showed that specimens treated with the new proc- ess were not progressively attacked but the acid-dichromate and chrome- pickle finishes were eventually de- stroyed after several hours’ exposure the above solution, leaving the magnesium metal exposed progres- sive corrosion. This effect may observed the abraded specimens shown Fig. which were immersed for hr. the above solution. check the wearability the new C.V.A.C. No. and finishes, the Taber Abraser was employed. This instrument was equipped with CS17F coarse calibrase wheels oper- ated under 1000-gm. wheel pressure. most cases, the chrome-pickle and acid-dichromate finishes failed after one two revolutions while the No. and finish- withstood more than 1000 revolu- tions. check the accuracy these observations, specimens shown Table were given 10, 100 and respectively, and subjected 24-hr. accelerated corrosion test previously described. This test definitely established the point that wear-revolutions the pickle and acid dichromate finishes were more damaging than 1000 either the C.V.A.C. No. finishes. Since these finishes have excellent resistance abrasion, their applica- tion prior forming, order pro- tect the relatively soft metal from injury through handling, was con- sidered plausible. Salt spray tests were conducted various methods forming, such dimpling, bending and rolling, 4—Salt spray tests conducted various methods forming. Column Received, chrome-pickle fin- ish, No. process applied before bending (unsealed); Column (2), same except one thin dip coat zinc chromate primer was applied before deg. bend; Column (3), except one thin dip coat zinc chromate primer was applied after deg. bend; Column (4), same except two thin dip coats chromate primer were applied, one before, and one after bending; Column (5), same but chrome-pickle and the acid-dichromate finishes are applied and 57S-H respectively, after bending; Column (6), same (5), but addition one thin dip coat zinc chromate primer was applied. a * — | | orro- elim- osion simi- early mate. 5—Magnesium aircraft parts which have been protected the process developed Consolidated Fort Worth division. The darker colored parts the left were anodized with whereas those the right were processed with AC. indicated Fig. 90-deg. bends. The new finish was compared the manufacturers’ chrome-pickle was observed that with the addi- tion the zinc chromate primer sealer for C.V.A.C. No. AC, applied either before after (or both before and after), the various forming operations, more protection was maintained than the conven- tional methods where the chrome- pickle and acid-dichromate finishes were applied after forming, plus one coat chromate primer. some instances, the finishes un- der discussion were exposed 500 hr. artificial sunlight and rain accelerated weather machine, operated without filters and equipped with No. and No. sunshine cop- TABLE Corrosion After 600 Hr. Salt Spray coat zinc chromate primer) Numbers Alloy Surface Finish Degree Corrosion Chrome pickle Chrome pickle Acid (dichromate) Acid (dichromate) Acid (dichromate) None CVAC No. CVAC No. CVAC No. CVAC No. CVAC No. CVAC No. CVAC CVAC No. CVAC No. CVAC No. IRON AGE, October 1944 Heavy attack Heavy attack Light attack Light attack Light attack None Trace corrosion Trace corrosion None None None Medium attack Medium attack None None None per electrodes. this machine the specimens were sprayed with water hourly and subjected intense ultra- violet radiation. The (unprimed) chrome-pickle fin- ished specimens usually developed traces corrosion after 100 hr. and the acid-dichromate after 300 hr. The unsealed C.V.A.C. No. and finishes revealed corrosion after 500 hr. exposure this test. Galvanic corrosion can very damaging magnesium, inasmuch the least noble all struc- tural alloys. The anodic coating pro- duced the new progress excel- lent dielectric and has, accordingly, been found act effective in- sulator prohibiting galvanic corro- sion when magnesium parts protected with the new finish are brought contact with dissimilar metals. The C.V.A.C. No. finishes have also been found offer more protec- tion salt-spray corrosion than the chrome pickle acid dichromate when contact with dissimilar met- als, which probably the result the greater depth the dielectric film produced the new finish. This should prove highly beneficial where magnesium alloys must brought contact with dissimilar metals, espe- cially the interior surfaces air- planes where moisture may trapped. 1 1 the water ultra- fin- reloped and The after very struc- pro- excel- dingly, in- corro- ight have protec- the met- This where ught espe- air- rapped. metals for use under corrosive know their relative resistance cor- rosion. The first step toward selec- tion ascertain the conditions which the equipment will likely exposed, next define the conditions possible and then compare the rates corrosion different materials un- der these conditions. comparing the corrosion resist- ance metals and alloys neces- sary consider the pattern the attack and the extent damage equipment. corrosion occurs the form pitting, intergranular attack, certain more serious than uniformly distributed over the surface. The loss metal terms weight loss per unit surface area therefore not necessarily measure the damage done. For example the loss metal resulting from the pitting tank the intergranular attack highly stressed airplane part negligible comparison with the extent the damage the functioning the unit. The engineer concerned with any type corrosion that may interfere with the functioning components. Tarnishing metals not normally important deterrent proper functioning and therefore not un- der consideration. using the following ratings important that consideration given the form which the metal used, that is, rolled metal, forgings. Moreover, the engineer should try visualize pos- sible damage caused types cor- rosion such deep pitting inter- granular attack. The engineer that consideration should effects intergranular corrosion un- der internal and applied stresses, par- ticularly cyclic stresses approaching the fatigue limits metals and al- loys corrosive atmospheres. Corrosion Ratings Metals These summarized corrosion data ferrous and non-ferrous metals were originally prepared the Westinghouse Electric Manufacturing Co. for the guidance its engineering staff. The information such broad usefulness and conveniently ar- ranged for reference that presented these pages for more general application. fabrication design develop such stresses, proper annealing redesign should reduce the probability failure. Comparative Ratings The selection metals and alloys for corrosive environments largely the problem chemical metal- lurgical engineer. The ratings given the tables are intended merely They are defined follows: A—Practically complete resistance, the alloy the best materials within its class. Probably safe use. B—Good resistance, proved being common use. May replace materials given rating secure Diagram typical galvanic action. Arrows indicate direction current; inside cell from anode cathode, out- side cell from cathode anode. Meter indicates cathode positive and anode negative some other advantage. Probably safe use. C—Adequate resistance under fav- orable conditions which should in- vestigated beforehand. Use only with caution. resistance adequate precautions are taken reduce effect corrosive conditions, coat- ings, cathodic protection, redesign, where appearance not im- portant and appreciable corrosion may provided for tolerated. Use should avoided unless protected unless appreciable corrosion can tolerated provided for. E—Poor resistance—use only better material not available. Use should avoided. Plus and minus signs are used permit greater differentiation tween rates corrosion resistance. Corrosion ratings for metals con- tact with salt water are subject wide variations, depending upon geographic location, speed flow and heating. Ratings given for sea water applications should con- sidered supplement other means arriving proper choice mate- rial. Corrosive Solutions Corrosion complex process. The expression opinion the probability corrosion similar forecasting the weather. Having considered all pertinent conditions, offered, but should certain conditions overlooked varied the mean- time, results may not predicted. THE IRON AGE, October chemical solution there are many factors considered such the concentration, temperature, move- ment and degree aeration the solution, and stresses, surface condi- tions and purity the metal. The selection materials for use chemical solutions specialized problem for the chemical engineer and can made only the basis information available him. The information required general too complex permit putting into the form table. Fresh waters vary tremendously the degree their corrosiveness, de- pending upon their source—lake, river underground—and upon con- tamination mines, sewage in- dustrial wastes. Since waters con- tain many impurities affecting their corrosiveness, they can considered somewhat similar chemical solu- tions. The selection materials for use them chemical engineering problem. extremely important that the engineer interpret the an- alysis the water and consider the possibility contamination with cor- rosive agents. This may require chemical treatment water the use corrosion inhibitors. The selection materials for atmosphere simpler than for that used chemical solutions. Data have been accumulated the comparative resistance corrosion typical out- door atmospheres and vapors com- monly encountered industrial proc- esses. Under the heading “Outdoor Atmospheres,” data rural, urban and marine atmospheres have been classified. sometimes difficult classify outdoor atmosphere. The atmosphere city along the sea coast would have urban and marine in- fluences. The corrosion rating should taken the worst the two. While intended that compari- sons made only vertical columns, there also tendency make com- parisons horizontally. horizontal comparisons are limited atmos- conditions, believed that useful conclusions may reached. For example, material having rating outdoor urban at- mospheres but lower rating for particular industrial atmosphere should carefully considered lest corrosion occur from industrial con- tamination the enveloping atmos- phere. This particularly true TABLE Corrosion Ratings Alloys Aluminum and Magnesium Data from the Aluminum Co. America Material Designation Rural Urban Marine Outdoor Atmospheres Ratings for Sea Water ALUMINUM AND ALUMINUM ALLOYS Min + + Aluminum alloys are used ammonia and hydrogen sulphide vapors but are not recommended for other corrosive atmospheres. These alloys may also used various concentrations acetic, nitric and chromic acids. The scaling temperature aluminum alloys above their melting points. With the exception zinc, alumi- num and magnesium alloys should not used contact with other metals the contact likely get wet unless insulating coating used prevent galvanic corrosion. Magnesium alloys are not recommended for use corrosive atmospheres. They are used solutions caustic alkalies, alkaline salts, and chromic acid. Mag- nesium alloys are not recommended for use above 400 deg. because the effect temperature mechanical properties. IRON AGE, October 1944 copper alloys since they are adversely affected many chemical vapors. Such precautions protective coat- ings air conditioning might then considered. Galvanic Couples When two different metals are contact and the contact area becomes wet with conducting solution, there electric potential set between them. For example magnesium and silver are immersed elec- trolyte, difference potential more than volt may exist between the two metals shown diagrammat- ically the sketch. Likewise dif- ferent metals and alloys are succes- sively brought into contact with silver any other metal, they develop characteristic potential and may listed the electromotive series be- low: (Data from The International Nickel Co.) ANODIC END Magnesium Magnesium alloys Aluminum Cadmium Aluminum 17ST Carbon steel Copper steel Cast iron 4-6% steel 12-14% steel steel Ni-Resist Ni-17 steel Ni-18 steel Ni-25 steel Ni-18 Cr-3 steel Lead-tin solder Lead Tin Ni-15 Active Ni-20 Brasses Copper Nickel silver Copper nickel Monel Nickel Inconel Ni-20 12-14 steel 16-18 steel Ni-17 steel Ni-18 steel steel steel Passive Passive Silver Graphite Gold Platinum CATHODIC END Combinations materials from dif- ferent subgroups should avoided, nor should combinations from extreme ends subgroups used when the area the metal higher the list smaller than that the metal lower the list. The higher metal from this list will suffer accelerated corrosion extent determined the corrosiveness the environment, ol na j Active MAGNESIUM AND MAGNESIUM ALLOYS ive dif- the area the more noble metal and the resistance the electrical circuit. When doubt whether active-passive material will active passive, assume that will active its area relatively small and passive its area relatively large. dangerous use metals the upper (anodic) end the list contact with those the lower (ca- thodic) end without safeguarding such contact coating other means keep from being wet with conducting solution. Sea water electrolyte high electrical conductivity and galvanic couples its presence should generally avoid- ed. This true especially the alloys aluminum and magnesium, iron, steel and brasses, contact with copper. If, however, the area the metal (anodic) which would very large com- pared the cathodic copper, the total galvanic corrosion will spread over this large area and the actual damage may not serious. Copper pipe usually connected with steel tanks without serious results; but use steel pipe with copper tank would probably result rapid corro- sion the pipe. The anodic metal suffers accelerated corrosion extent governed the corrosiveness the environment, the relative area the cathodic metal and the re- sistance the galvanic circuit which consists the two metals and the solution. Sometimes galvanic couples not result attack the TABLE Corrosion Ratings Alloys Iron, Nickel and Chromium Data from the International Nickel Co. Outdoor Atmospheres Specific Industrial Atmospheres (Wet) caling Temperature Hvdrogen Sulphur Steel Alloy Type No. Rural Marine Sulphide Dioxide 0.60% 416 23-30% oxidation 304 1% Cb 14% Ni-23% Note 2—1900 Nickel Note 3—1000 Note 700 Note 2—1000 Note 3—1000 Note 650 80% Ni-20% 2100 Note 2—2000 Ni, Note 3—1500 Fe-13% Note 4—1000 Note 1—Values assume substantially constant temperature operation. They are lower for cyclic heating and cooling extent dependent upon the frequency and range temperature fluctuations. Note 2—Scaling temperature low sulphur atmosphere. Note 3—Scaling temperature high sulphur oxidizing atmosphere. Note 4—Scaling temperature high sulphur reducing atmosphere. Note 5—Not recommended primarily resist ammonia attack, but may used where resistance ammonia low con- Note 6—In stainless steels, the poorer ratings refer exposure quiet slowly moving sea water, especially where marine organisms may become attached and induce pitting. The better ratings refer contact with sea water high velocity, such encountered pump impellers for which the higher alloyed stainless steels frequently give excellent service, especially polluted harbor waters. The straight chromium stainless steels perform best when used high velocity installations. They should not come into galvanic contact with bronzes. Note 7—The 70:30 copper nickel alloy preferred for condenser tubes, salt water piping and boat sheathing. Monel provides high strength, excellent resistance erosion, and favorable galvanic relationship bronzes. the preferred material for valve trim, shafting, and for vital parts assemblies which include bronze components. THE IRON AGE, October ely at- 1en nes ere een lec- een dif- ces- lver Provisional Ratings for Sea Water Note Note Note Note Note CtoE Note CtoE Note Note Note Note Note SS treme the list metal metal erated ment, anodic metal might expected. The condition which prevents expected attack has been named sivation, but has received pends upon the nature the solution. the the solution one which destroys pas- passivity, the alloy then said uni- have become active and will at- versally accepted explanation. containing chromium are most nounced their passivity which ac- pro- These active-passive alloys are des- ignated three groups, and counts for its wide use which under certain conditions resistant alloys. Passivity also de- become active and are then higher the list. obvious that the conditions use must gated before passive metal alloy recommended. When doubt whether active-passive material will active passive, assume that will active its area rela- tively and passive its area relatively large. TABLE Corrosion Ratings Copper and Copper Alloys Data from the American Brass Co. Outdoor Atmosphere Hydrogen Hydrogen Sulphur for Material Rural Urban Marine Ammonia Sulphide Dioxide Sea Water COPPERS BRASSES LEADED BRASSES PHOSPHOR BRONZES SPECIAL BRASSES CUPRO-NICKELS SPECIAL BRONZES Used principally for electrical resistance properties. 62—THE IRON AGE, October 1944 first symptoms inhala- tion cadmium containing dust and fumes are usually dryness the throat, cough, headache, vomit- ing and sense constriction the chest. Later symptoms are predomi- nantly referable the respiratory system and are characterized cough, pain chest, severe dyspnea and prostration. Such severe lung damage usually manifests itself hours after exposure, and cadmium fumes can breathed fatal concentra- tions without enough discomfort drive the worker away from the ex- posure. Ingestion cadmium salts through eating and drinking acid food products which have been con- tact with cadmium plated articles has also caused number cases poisoning. Extensive study missible concentrations cadmium has not been made with respect ex- posure human beings. However, the American Standards Association its “American Allowable Concen- trations Cadmium” has accepted air. Few unsuspected hazards surround the cadmium plating operation itself. Cyanide plating solution poisonous care should taken that does PAUL NEAL and LAWRENCE FAIRHALL Industrial Hygiene Research Lab. National Institute Health Bethesda, Md. and GUSTAF SODERBERG Conservation Div. War Production Board not reach the mouth the operator either splashing way his hands. Where insoluble steel anodes are used, for example, plate into deep recesses, considerable spray may evolve from the plating tank. such cases the tank should ventilated the same fashion chromium plat- ing tank. greater hazards are en- countered operations incident cadmium plating. mixing plating solution imperative that cadmium containing salts not inhaled. Burning Cadmium Dangerous particularly dangerous burn cadmium. Deaths are recorded having taken place when workman has used blow torch burn off cad- mium plate from inside tanks and from plating racks. Cadmium should removed electrolytic chemical stripping. Plating departments should avoid remelting cadmium scrap un- less the melting equipment thor- oughly ventilated. better send the scrap the anode supplier who has satisfactory equipment and knows how process it. common heat cadmium plated parts an.oven for the pur- pose eliminating hydrogen embrit- tlement. Such heating requires care- ful temperature control that cad- mium fumes are not formed process. Care must taken that the specified temperature not exceeded any part the oven. Industrial accidents have recently occurred from welding operations out cadmium coated ar- ticles. Where cadmium fumes are evolved and space limitations not permit the use adequate ventilation, work- men should supplied with positive pressure masks. Where acid fumes are also present, soda lime cartridge should attached the respirator. There record any cadmium poisoning caused handling cad- mium plated parts the assembly line elsewhere. is, course, wise precaution wash the hands before subsequently handling food. Welding Machines Converted Generators HARRY BAYLIE Chief Electrician, Mathis Shipbuilding Corp. ° RECENT contract for Army boats required the use power generator for test purposes and for supplying ships with auxiliary power the fitting out dock. These boats require 230 volts d.c., three wire service for power and lighting. Unable obtain mo- tor-generator set inside six months’ delivery, was decided little experimenting with generators. The requirements called for 40- kw. generator, since the largest piece equipment tested was hp. 230 volts d.c. Since group Hobart arc welders con- nected for constant potential were found have good regulation, by. ex- Photo courtesy Hobart Brothers Co. using separate switches each gen- either 115 230 volts. perimentation was found that they could put out 115 volts without very costly changeover. This change was made substituting additional shunt winding place part the series field coils and making these extra shunt coils self-exciting. connecting two these machines series 230 volts was. obtained, with midtap 115 volts. Although their combined output should really more than kw., trouble was en- with these machines run- ning considerable overload for lim- ited periods time. All power facilities the piers and ways terminate power pane