The Iron Age 1945-06-14: Vol 155 Iss 24

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Vol. 155, No. AGE June 14, 1945 Editorial ° Technical Articles Setup Charts for Automatic Screw Prefabricated Snap-Assembly Rugged X-Ray Tube for Portable Weldability High Strength, Low Alloy Steels (Part ° ° fo) Features ° ° ° News and Markets Military Vehicle Report Made........................ 114D Lack Information Called Foreman’s Grievance Lid Off Navy Steel Shell 116 More Overall Cutbacks Reported 120 Machine Tool Market 154 Nonferrous Metals News and Iron and Steel Scrap News and Comparisons Prices Week and Year Finished and Semi-Finished Steel 162-3 Warehouse and Steel 164 Iron and Steel Pipe and Tubing Exceptions Steel Price Schedule Pig Iron and Coke Prices................. Bolts and Nut 169 Stainless Steel and Ferroalloy Prices 170-1 ° ° Index Advertisers 250 4 $2.70 2.90 $1.50 25c. 26c. 58c. 60c. 1.23 1.25 1.35 1.40 5.00 5c. { Se. engineering metallurgical fabricating Are you thinking stepping-up vour post- war product production with little much stainless? there stainless problem your present production? Then get technical service that dates from 1925 when Ryerson first stocked Allegheny Stainless. This tech- nical service available small users well large —reaches you quickly because there-are conven- iently located Ryerson Steel-Service plants. Ryerson stocks Allegheny Stainless exclusively the best the stainless steels. More than types are stock. Shipments are prompt because stocks are large and diversified. Joseph Ryerson Son, Steel- Service Plants: Chicago, Milwaukee, -Detroit, St. Louis. Cincinnati, Cleveland, Pittsburgh, Philadel- Buffalo, New York, Boston. have Ryerson IRON AGE, June 14, 1945 : | | : | | 7 J 4 / 3 j ‘ types Allegheny Stainless June 1945 VAN DEVENTER President and Editorial Director ESTABLISHED BAUR Vice-President and General Manager Editorial Technical Editor ........ OLIVER News Editor JACK HIGHT ALBIN JOHN ANTHONY BARMASEL Editorial Assistants SCHIEN MILLER HANSEN DAVIS News and Editors LLOYD Pittsburgh 428 Park POST Chicago 1134 Otis Bldg. MOFFETT EUGENE HARDY ANSBORO Washington National Press Bidg. Cleveland Guardian Bidg. BRAMS Detroit 7310 Woodward Ave. OSGOOD MURDOCK San Francisco 1355 Market St. Editorial Correspondents ROBERT Cincinnati DEAN Buffalo FRAZAR Boston HUGH SHARP Milwaukee SANDERSON Toronto, Ont. RAYMOND KAY Los Angeles John McCUNE Birmingham ROY EDMONDS St. Louis JAMES DOUGLAS Seattle The Competitive Spirit ERMANY had military drill down pat. Her soldiers marched and counter-marched with clock-like precision. Even the ridiculous goose step was attainment not lightly acquired and exemplified exactness timing. The German people liked watch their soldiers Whether they would have paid admission fee see them another question for none was charged. was free show with sales promotion motive selling the public the war spirit and regimentation. People who like regimentation not care for such American sports baseball and football. And the same token and reverse, Amer- icans not take pleasure regimentation. fill baseball stadiums and football fields capacity substantial admission price and will sit for four hours more watching double-header. Imagine getting West Point cadets march and down. This American fondness for competitive sports national charac- teristic. Americans like compete next best watch others it. Competition puts the spice adventure into life, whereas regimenta- tion kills it. must hold fast this national characteristic for has made what are and without cannot become what want be. That something think about very seriously these days when there are opposing views what should and what should done our postwar period. Especially important our future will the relation govern- ment business. business not mean just trade but everybody’s business whether managing steel plant shoveling ore into furnace. There are some who want government make the plans for business _as well make the rules for it. Germany did that. had master plan; fascistic concept that led inevitably through regimentation into the disastrous concept the master-race. like Paul Hoffman’s idea competition planning, exempli- fied the activities the Committee for Economic Development. endeavor get two million individual employees make two million individual plans for the future their businesses, rather than torced follow master plan set few selected individuals. Americans race not like the word “master” nor its obverse which connotes condition slavery. Getting back baseball, the most loved American sports, think government has much learn from it, considering its own future relation business. Anything can happen baseball game and usually does. The spirit competition and team work allowed the fullest play, but all plays are made subject the rules. The umpires not compete with the players. baseball, the rules are simple and thoroughly understood the players. And they are not changed during inning, game series. That’s the way should be, think, our relationship between government and everybody’s business, including yours and mine, our American postwar World Series. | | qj Inland research and product development have more than kept pace with demands for better flat rolled steel products. They have consistently anticipated manufacturers’ needs —giving them infinite variety steels that fully meet the requirements modern design and manufacturing methods. There are Inland hot rolled sheets and strip, and cold rolled sheets and strip, that can easily formed, deep drawn, spun, welded, and beautifully finished—steels that make stronger, more durable and more attractive products. Inland specialists are ready help you select the right steel for war products and for products you plan make after the war. They are highly skilled the making spe- cial steels for every particular purpose. They are thoroughly grounded shop methods, and consumer needs and desires. You are invited take advantage their services. Bars Floor Plate Piling Plates Rails Reinforcing Bars Sheets Strip HELP WITH WAR Special Steel for Every Purpose PARTIAL LIST INLAND FLAT ROLLED PRODUCTS Hot rolled strip Hot rolled sheets Deoxidized sheets Pickled sheets Electrical sheets Blued Stovepipe stock Cold rolled strip Cold rolled sheets Enameling sheets Galvanized sheets Commercial coating Tite coated Form-cote sheets Extra heavy coated Paint-Tite sheets Zinc alloy sheets Copper alloy steel sheets Tin plate, hot dipped and electrolytic terne plate Tin mill black plate Tin Plate Track Accessories INLAND STEEL COMPANY Dearborn St., Chicago Ill. Sales Offices: Cincinnati Detroit Indianapolis Kansas City Milwaukee New York St. Louis St. Paul x io! 3 4 ree | he: News Front June 12, 1945 Germany, second largest steel producer the world, will have its ingot imited some 4,000,000 5,000,000 tons yearly assure ete equipment will scrapped, and most the heavy forging and centrifugal ing installations will either destroyed removed. Decisions regarding the future the Herman Goering works Braunschweig with great interest. This German plant one the largest modern the world, and may fall within the Russian zone occupation. Sintered carbide penetrators were used most German shells. Toward the the demand for large sizes was great that procedure was developed penetrators into compacts for large shells. new sintered carbide has been developed the Germans, simpler than those the world and capable equal superior performance cutting ions. Demonstrating the impact jet aircraft requirements stainless steel ion, only about half the output now the 18-8 group. ontinue the upgrade, with make determined the engineering design the item for which the steel used. Columbium and titanium have gained particular importance. Producers expect that with return uses the 18-8 group again will predominate. 200,000 passenger cars authorized for production the United Kingdom hext twelve months, half are earmarked for overseas export. The official for automobile production England was dated June ll. Also authorized for production bolster England's foreign trade are and some additional hard goods. Economic Stabilizer Vinson staies that cutbacks munitions the third amount per cent, and per cent the end the year. six volume production will the 1943 level. Washington continues concerned about the impact cutback news war centers. Considerable effort being made some agencies prevent timely news handling. effort being made, however, speed reconversion and avoid labor ion furnishing information with plant data for the use manufacturers through business press. Official thinking that what information released only the use local newspapers the areas affected. Setup charts for automatic screw machines have been developed hese charts are particular use problems involving approximations feeds, speeds and related data that the answer can arrived the matter the mere process visual analysis, eliminating the necessity for length ions. These charts have been developed for automatic screw machines which the driven the spindle drive shaft, like the Conomatic screw machines and for machines which the feed mechanism independent the spindle drive, like Brown &.Sharpe, Davenport and Cleveland machines. Superior atmospheric corrosion resistance certain high strength steels the more dense, tightly adherent and highly protective rust coat which forms heir surfaces. One particularly important characteristic this type rust its uniformity. practically free from spalling. Because the inherent corrosion resistance the low alloy, high strength even greater weight saving can obtained mobile structures where osion controlling factor determining thickness plate, than strength alone would dictate. The inability steel exporters get any information regard future creating fear that least for the next few years dealings will State Department for most export trade, under some revision modification Paul 3 - — SETUP CHARTS For Automatic charts contained this series articles were originally conceived the author or- der save extensive work comput- ing and determining feeds and speeds _and related data the course in- vestigating the manufacture screw machine parts under the unusual cir- cumstances presented wartime con- ditions. After the initial charts were developed, their usefulness and utility were apparent that was found advisable devise similar charts for other types machines, particularly feed change gear setups for in. spindle Acme-Gridley screw machines. those like the Davenport wherein the relationship feed per revolution not readily obtainable. this way all guesswork with relation this factor would eliminated. The charts developed for use setting Daven- port screw machines were success- ful that the author then turned his attention the development charts for the design cams for use Brown Sharpe screw machines. These charts are particular use problems involving successive ap- proximations that the answer can ia i + | | | | COARSE FEED SPINDLE 2—Fine arrived the matter sec- onds the mere process visual analysis, eliminating the necessity for lengthy computations. The enormous saving time and effort with the elimination errors readily ap- parent and these charts should prove ers, time study men, methods engi- neers, foremen, setup men and oper- ators usefulness for the latter categories should giving these men better understanding and visual indication the limitations change gear setups for in. spindle Acme-Gridley screw machines. 0.125 0.050 0.120 FEED { 0.075 1400 1300 1200 1100 0.050 1000 Spindle speed, r.p.m 0.020 0.015 hange n 54—THE IRON AGE, June 14, 1945 0.010 0.005 Feed per revolution, Q hange gears and The divide whose the entire forme feed upon the speed feed norm: tions. feeds result tools, ineluc ti-lob puted depen tions Often and precis that mach curve the actua the time bility Ine matic Feed per revolution, and possibilities their machines. These machines generally can divided into two classes: (a) Those whose feed mechanism driven the spindle drive shaft, and (b) those whose feed mechanism driven entirely independent drive. the former category, the relationship feed per revolution depends entirely upon the feed change gears installed the machine. Changing the spindle speed has effect upon the feed per revolution. the latter category, feed per revolution can determined normally only lengthy computa- tions. For that reason, most cases, effort made determine the feeds and speeds such machines; instead guesswork resorted to, with resultant overloading machines, tools, and materials. this latter category, also, are included machines having special mul- ti-lobe cams which have com- puted. many cases these designs depend upon successive approxima- tions arrive the correct design. Often this requires complete redesign and order cut corners rough ap- proximations are substituted for more precise calculations, with the result that actual feeds and speeds are un- known. This often causes overloaded machines, tools and materials. The curves presented this series enable the designer base his layout upon actual feeds and_ eliminating guesswork and increasing the efficiency operation, the same time eliminating the necessity for lengthy computations and the possi- bility errors resulting therefrom. Included those types auto- machines which the feed mechanism driven the spin- dle drive shaft are such machines the National-Acme, and New Britain-Gridley screw machines. the latter category which. the feed mechanism drive independent the spindle drive, are included the Brown Sharpe, Davenport, and Cleveland screw machines. The for- mer type machine, because the simplicity the factors involved per- mits the use rather simple form chart which therefore will pre- sented first. Because the independent drive Screw Machines thereby ° JOHN MEADOWS Development Engineer, Development Division, Curtiss-Wright Corp. ° graphical methods, problems involving speeds and feeds can solved fraction the time necessary make the calcu- lations from handbooks. the first articles the series, charts are presented for various sizes Acme-Gridley screw machines. succeeding articles, change gear setup charts will printed for Conomatic, New Davenport and Brown Sharpe screw machines. the latter type screw machine, addi- tional factors are introduced which considerably complicate the problems involved the extent that successive approximations must introduced order arrive satisfactory solu- tion. Although the actual computa- tions used arriving the solutions for the latter type machines are rather complex, the graphical solution the problems means these charts actually resolves itself into very simple visual analysis eliminat- ing entirely the need for any complex equations. Simple rules procedure will presented for each make machine which, followed, will make possible the rapid solution any problem within the limitations the charts. Acme-Gridley Machines The Acme-Gridley bar machines are the least complicated all machines considered. They are multi-spindle machines driven from main drive shaft located the right hand tower the machine. This shaft provides direct drive the main drum shaft through roll over-running clutch for the high speed movement the drum shaft during the indexing and stock feeding operations. also equipped with two speed clutch for high and low spindle speeds. This lat- ter clutch meshes with mating gears the spindle speed change gear shaft which turn drives the spindle drive shaft through change gears. These change gears are represented the charts and are chosen means the vertical line passing through the spin- dle speed curves the nearest avail- able spindle speed the one desired. These available speeds are represented encircled dots along the spindle speed curves. There are two these curves each sheet one marked and the other Lo, corresponding with the high low speed setting the clutch. most Acme-Gridley screw ma- chines the spindle change gears and the feed change gears are located the right hand end the machine be- hind removable cover. The spindle change gears are usually the right and the feed change gears the left when looking into the enclosure and are interchangeable. the in. however, feed change gears are located box the front side the machine. This type installation differs from the others only the extent that there are four feed change gears instead two. Otherwise, the effective drive the same. The driver gear the feed change gear unit mounted the spindle drive shaft geared that change spindle speed will not affect the feed per revolution pro- vided that the feed change gears have not been altered. The main drum shaft driven from the feed change gear shaft through main worm gear. Normally this drive from the feed change gears which provide the desired feed per revolution during the cutting operation. However, during the indexing and feeding operations, the high speed disk clutch engaged and this overdrives the main drum worm through the roll clutch men- THE IRON AGE, June 1945—55 iS 0 >? Change gears 3—Coarse feed change gear setups for in. spindle Acme-Gridley screw machines. tioned previously. The feed drive these machines provided with high-low speed clutch excepting those machines equipped with four change gears which enables them have the same range feeds. The movement the main tool slide controlled cam mounted the main drum shaft the ac- tuating the high speed disk clutch. Also mounted the main drum shaft are the chucking, stock feeding, in- dexing, stock feed stop, brake, thread- ing and reaming cams. Each cross slide has independent operating drum cam crank driven gearing from the main drum shaft. Individual positive stops are provided for the cross slides order insure the proper sizing machined parts. The charts, Figs. 1-5, are used follows: The desired spindle speed found along the left hand edge the chart and the corresponding horizontal line 56—THE IRON AGE, June 14, 1945 0.009 Change gears 4—Fine feed change gear setups for in. spindle Acme-Gridley screw machines. followed the right until the spin- dle speed curve intercepted. The nearest encircled dot the spindle speed curve the nearest obtainable speed the machine. The vertical line through this dot followed the bottom the sheet and the proper change gears are found that line. Then the desired feed selected along the right hand side the chart and the corresponding hori- zontal line followed the left its intersection with the proper cam curve. The nearest vertical gear line this intersection adopted and the exact feed determined from the hori- zontal line passing through this inter- section. After the feed gears have been determined give the correct feed for the principle element the operating cycle the feeds for the other elements can determined merely following the vertical line ing with these gears its intersec- tion with the various cam curves cor- responding the cams use. The feeds will indicated the horizon- tal lines passing through these inter- sections. Should the feed for any element too high too low, familiarity with the chart will indicate whether the cams should changed different feed gears installed both, and how much change should made. Example for In. Size Assuming that spindle speed 1100 r.p.m. required with 0.006 in. feed per revolution the princi- pal operation for which in. cam necessary, and assuming that feed any operation exceed 0.008 in. and that the other cams are the in. spindle Acme-Gridley charts, will found that the cam ranges out the feed zones the coarse feed chart, Fig. whereas Feed per revolution, in. 0.024 1300 cent vert 0.022 1200 gin, 0.020 1100 010 sibl . 0 reg ota an his Feed per revolution, in. 0.006 rinci- cam xceed are ridley cam the eas easily determinable the fine feed chart, Fig. Therefore, horizontal line ex- tended the right from 1100 r.p.m. Fig. will intersect the curve about the middle the chart and the nearest obtainable speed for this machine will found 1080 represented the encircled dot the spindle speed curve. This represents error less than per cent and not objectionable. the vertical line followed from the above intersection the lower mar- gin, the spindle change gears respon- sible for this condition will found, this case 44/60, the tooth gear being the driver and tooth gear the driven member. horizontal line drawn from the right hand side the chart 0.006 in. feed intersect the in. cam curve, the recommended change gears will found the 48/56 combination. However, the other feeds must first checked see that all requirements are met. This done following the vertical 48/56 change gear line its intersections with the and in. cam curves. The in- tersection the in. cam curve in- dicates 0.003 in. feed. The inter- section with the in. cam curve should interpolated between the and in. curves which will indicate 0.0038 in. feed. The intersection with the in. cam curve will indicate 0.009 in. feed. This per cent too high and would result tool trouble from overloading. Therefore, the feed change gear line must shifted the left reduce the feeds. This done following the in. cam curve until indicated feed 0.008 in. has been reached. This the maxi- mum permissible value. the next adjoining gear line the in. cam curve indicates 0.0082 in. feed which only 2.5 per cent plus error and permissible. the other cams are checked, the errors for the 46/58 gear line will amount only per cent minus. These are approximately correct and the di- rection improved performance consequently the 46/58 change gears should used. This method ap- plicable all the Acme-Gridley charts except the in. machine which requires different technique. Example for In. Size With reference the in. Acme- Gridley machines, analytical chart presented Fig. showing the feeds obtainable with the four change Feed change gears CHANGE GEAR ACMES 1000 wo on NN N SET-UPS FOR 0.022 pindle change gears FIG. 5—Change gear setups for in. Acme-Gridley screw machines. gears provided. These are indicated the chart points corresponding with the gears given the setup chart. These are indicated encircled dots. corresponding linear chart given along the right hand edge the main chart. However, the National Acme Co. does not normally furnish gears corresponding with the data furnished. The gears normally furnished cor- respond with the points enclosed triangles the chart. The points enclosed squares differ from the data furnished the National Acme Co. and have been substituted or- der produce continuous curves the setup chart. will noted that the data for many these gear set- ups are interchangeable that they give the same results. illustrate the charts designed for the in. Acmes, assumed that spindle speed 2400 r.p.m. desired and 0.011 in. feed with the in. Acme-Gridley setup chart (Fig. 2400 r.p.m. and intersects the curve. The nearest obtainable speed indicated 2370 This per cent minus error and permissible. The change gears would the tooth driver and tooth driven gear. the same manner line drawn from the right side 0.011 in. feed. This line traced its intersection with the in. cam curve, from which vertical projection indicates P-K gear combination for the feed drive. Referring the gear reference chart, THE IRON AGE, June 14, 1945—57 2500 w 0.048 GEAR 2400 AS) 0.046 TTERS 3 50-50 1800 0.034 52-48 7 03 5 64-36 a 1100 0020 900 0.016 eu“ 500 The inter- ° with the erent how le. Change gears obtainable with in. cam with available change 7—Coarse feed change gear setups for 9/16 and in. gears for in. Acme-Gridley screw machines. Acme-Gridley screw machines. the letter represents tooth driver and tooth driven gear, the latter the jackshaft. The letter represents tooth driver and tooth driven gear, the former the jackshaft and the latter the feed driveshaft. Unless the machine happens specially equipped with complete set change gears ranging from teeth, will not equipped with gears. will necessary, therefore, make substitutions. For this purpose, reference chart entitled “Feeds Obtainable with in. Cam with Available Change Gears for 1%4 in. Acme-Gridleys” used, Fig. the right the chart are two 58—THE IRON AGE, June 14, 1945 columns letters representing re- spectively the change gears listed the Acme handbook and those that are furnished with the machines. Since this operation involves in. cam, this chart can used directly without correction. Such correction would proportional the rise the cam. Therefore, line drawn the right from 0.011 in. feed and followed the first column letters. Here the letters P-K are found, the combination that was obtained the main chart. Opposite this the sec- ond column the letters are found. Either these combinations will give the same results will all combina- tions represented the intersections along the 0.011 in. feed line. All com- binations any feed line are inter- changeable. Since the L-O gears are standard these machines, they should available. They represent 48/52 and 54/46 tooth combinations and would the gears use, pro- vided all operations check for proper tool feed. Tapping Charts Charts are also provided readily determine desirable proper tapping drive gears for each available size machine (See Figs. and 11). These charts give clear visual pic- ture how tapping accomplished. ~ FOR ACMES speed, 5990, 4 900 800 600 500 400 TT TMHMHH HO Change gears For right hand tap the tapping spindle driven the same direction the main spindle but propor- tionately slower speed. Two such speeds are usually provided for choice. The actual cutting speed the difference between the speed the main spindle and that the tap. Withdrawal accomplished speeding the tap speed greater than the main spindle. The chart used follows: Enter the chart the main spindle machine. Intersect the 100 per cent curve and use the vertical line through this intersection arriving the proper tapping gears. The intersec- tion this vertical line with the tap- ping and withdrawal curves will give 2300 2200 2100 2000 1800 600 0.019 1500 400 Main spindle speed, r.p.m. ABOVE 9—Tapping spindle gear setups for in. Model spindle Acme-Gridley screw machine. ° ° ° LEFT 8—Fine feed change gear setups for 9/16 and in. eme-Gridley screw machines. the speed the tapping spindle shaft. The speed that best suits the required conditions should selected. The necessary gears give that speed may determined the right hand end the tapping and withdrawal curves. For high speed drill spindles, the usual ratio Acme-Gridleys 100 per cent, giving speed up. Tapping Example cut in. thread with peri- pheral cutting speed approximately f.p.m., the speed should approxi- mately 350 r.p.m Assuming that the main spindles are turning 2000 r.p.m. and that the work being done in. Acme, the tapping chart for the in. Acme, Fig. 11, vertical line drawn the 2000 r.p.m. line the bottom the chart and followed the 100 per cent which the point zero differential the point where both spindles are turning the same speed. cut right hand thread necessary for the tap spindle turn more slowly than the main spin- dle. Since the main spindle operat- ing 200 r.p.m. and the desired cut- ting speed 350 r.p.m., the tap spin- dle should rotate 1650 find this point, the same vertical line followed down (2000 r.p.m.) dis- tance 350 r.p.m. which will the horizontal line representing 1650 r.p.m. The nearest tapping curve THE IRON AGE, June 14, 1945—59 0.025 0024 0023 0.022 2400 0.008 200 0.007 100 0.005 iter- are they sent pro- oper ping size pic- shed. Main speed, spindle gear setups for in. Model spindle and in. Model RAS spindle Acme-Gridley screw —Tapping spindle gear setups for and in. machine. spindle Acme-Gridley screw machines. indicates cutting speed 466 r.p.m. thereby increasing cycle times. 1040 r.p.m. provided change f.p.m. this satisfactory, such case compromise would have been made spindle speeds. Know- the 30/45 gear combination should effected. ing the number threads cut, used. not, special gear combina- For withdrawal, the 43/32 gear the exact cycle times can deter- tion, such 31/44 which would give combination would used and mined from these speeds. cutting speed 390 r.p.m., should would determined from the succeeding issue charts for Con- used. place this would that withdrawal would 3040 machines will pre- necessary reduce spindle speeds, giving withdrawal speed set which makes possible rivet Z-type angle sections with both speed and ease Chi- cago automatic riveter has been developed Consoli- dated Vultee Aircraft Corp., San Diego. indicated the. ‘illustration, the set has angle equal greater than the angle the This elimi- nates the standard set interference which frequently makes impossible rivet angles automatically. The new set can also used for the riveting assemblies with other types structural angles. 60—THE IRON AGE, June 1945 4200 4000 3400 3400 200 ter tic P High Strength Steels ONSIDERABLE confusion has been caused the minds consuming engineers account the lack official terminology for the group steels which are basic this discussion. The terminol- ogy commonly applied includes the following: High tensile steel, low alloy steel, mild alloy steel, high yield steel and even lightweight steel. Not all these designations are accurate and some are even misleading. The term “corrosion resistant, high strength steel” preferred the author, but for the sake brevity “high strength steel” will used this discussion. large steel producer, who pio- neered one the earliest and best these compositions more than decade ago, has promulgated definition which specifies the following: “The term low alloy, high strength steel meant include steels which mod- erate amounts alloying elements have been added, imparting the as- hot-rolled condition yield point 50,000 lb. per sq. in. minimum, sec- tions in. thick and lighter, and which experience indicates will result atmospheric corrosion resistance four six times that mild steel.” minimum degree several im- portant properties must possessed composition suitable the pur- poses for which this group superior steels was designed. Otherwise, would inadequate serve engi- neering needs some one more respects, and would therefore dis- qualified. considering this subject, sometimes illuminating point out that this group steels was de- veloped displace ordinary struc- tural steel for many important uses large tonnage markets. the group thought comprising better grades ordinary steel which have resulted from metallurgical progress and advancement the art steelmaking, good bit the mystery and confusion which sur- round them will avoided. Too fre- quently some one the essential properties high strength steel overemphasized, and thus given de- gree importance out proportion its rightful place the overall en- Pace Lightweight Development Because the inherent corrosion resistance the low alloy, high strength even greater weight saving can obtained mobile structures where corrosion controlling factor deter- mining thickness plate, than strength considerations alone would dictate. The author evaluates these steels from their relative tech- nical and economic advantages for the construction railroad rolling stock, mine and dump cars, trucks and and barges. FOOTE Alloys Development Corp. Pittsburgh gineering problem. Gratifying would find material ideal all its characteristics, such happy outcome expected metallurgists and engineers practical turn mind. seems wise, therefore, consider the homely adage that “good enough the best”; that anything more than adequate degree each the several properties essen- tial the purpose superfluous and can obtained only adding cost. The overemphasis which placed upon the importance one property when compared with another arises times from desire for foolproof degree some characteristic the material, without regard for proper balance other essential properties. Thus, welding engineer would mark adaptability for welding his cri- terion quality; the boss the fabricating shop, forming character- istics; maintenance engineer, cor- rosion and impact resistance, and the purchasing agent who some- times has played down quality con- siderations favor price. Since all must concerned with inte- Mechanical Properties Ordinary Structural Steels and High Strength Steels Compared Structural Steel AAR thick and under (Grade (Grade (Grade (Grade Elongation Speelmen cold bend (Grade (Grade (Grade 0.5 Tens. Str. 50,000-62,000 per cent per cent 1,500,000* T.S. 180° 186° Flat Structural Stee! Typical Example 0.5 Tens. Str. but not less than 33,000 60, 000 50,000 min. 70,000 min. per cent per cent 1,500,000* T.S. For material under thickness deduction 1.25 per cent made for each diameter below in. THE IRON AGE, June 14, | In. thick and under In. thick and under grated balance the several prop- erties essential given purpose, reasonable discuss the charac- teristics these steels from the standpoint their utility for the par- ticular services which they are used. The aim this discussion examine the characteristics high- strength steels well qualified for the construction, modern lightweight design, mobile structures used transportation railroad freight and passenger cars, street cars and buses, mine and dump 62—THE IRON AGE, June ° ° OPPER coal car built copper bearing carbon steel after years, months service. Side, slope, and hopper sheets are and 5/16 in. thicknesses. Note spalls loose rust the sur- faces the metal. trucks, truck bodies and trailers, ships and barges. First costs, operating costs and service will determine the choice material best suited for the design such struc- tures. this method selection, corrosion and abrasion resistance, and what may referred descriptively toughness, are first considera- tion. Adaptability for welding and forming must possessed ade- quate and satisfactory measure, but the utmost weight saving for low cost operation the chief objec- tive, structure, when built OPPER coal car built Cor-Ten steel after ten full years service. The side, slope, and hopper sheets this cor were 3/32, and 5/32 in. thicknesses. Note dense, uniform rust coat which hos protected the ° ° placed service, must able “take it” terms day-to-day pun- ishment, and keep taking over its economic life span, without loss essential strength and premature failure due largely corrosion. This assurance cannot provided mod- ern lightweight design without em- ploying materials which possess marked degree atmospheric corro- sion resistance and, hence, con- tended that this the most impor- tant the several properties essen- tial high strength steel. Protective Oxide Coating Service experience, well exhaustive amount testing, has demonstrated clearly that the superior atmospheric corrosion resistance certain high strength steels due the more dense, tightly adherent, and highly protective rust coat which forms their surfaces. has been found that under the usual atmos- testing conditions about 0.2 gm. per sq. in., about 0.002 in. thickness the better corrosion-re- sistant steels used supplying the metal required form good pro- tective oxide film. period ex- posure least years and preferably longer, depending upon the alloying elements employed, quired ascertain the trend the probable atmospheric sistance behavior high strength steel. One particularly important char- acteristic the type rust coat which forms the atmosphere the subject steels its uniformity. practically free from spalling; the formation tubercules warts rust which aggravate pitting and cause corrosion progress steadily. The seriousness and magnitude the spalling found with plain carbon copper-bearing steels may visual- ized the fact that over short period years car shop, which spe- cialized heavy repairs steel cars, accumulated several thousand tons and later when market for iron oxide developed, also sold several thousand tons iron ore. Tendency spalling, which exposes fresh sur- faces the weather, resisted the relatively thin, tough and adher- ent rust coat these corrosion resis- tant steels. those who are familiar with the electrolytic nature the corrosion processes, the advantages this type scale will apparent. Paints, surface preparations for painting and methods paint appli- 7 3 pun- over loss ature This mod- em- sS a con- npor- ssen- has erior and been n-re- the pro- and the re- the re- ngth coat the the and the sual- short spe- cars, amp, iron sur- the ages rent. for ppli- eation are varied that quantita- tive statements can made the longer life and greater adherence paint the surfaces these steels. However, seems apparent from the paint performance the many freight cars built from corrosion re- sistant steels that the facts referred above contribute greater ad- herence and, hence, longer life the paint. examine the influence the individual elements the atmos- pheric corrosion resistance fer- weight this box car corro- sion resistant, high strength steel 36,- 800 compared with 45,000 Ib. for standard A.A.R. car copper steel the same inside dimensions. Auto- matic arc welding was employed for attachment side sheets framing members. Built General American Transportation Corp., Chicago. rous material, find that some are definitely beneficial when used alone, some slightly and others nega- tive effect even harmful. When used combination, these same elements are sometimes surprisingly beneficial and manner not expected their effect upon corro- sion resistance when used alone. other words, the corrosion expert has found that sometimes two and two make five. There are several reasons for using more than one alloying element produce the physical properties good high strength steel, and this turns out favorable circum- stance regard corrosion resis- tance. phosphorus, which probably the most effective element for improving atmospheric corrosion resistance when used alone, even more beneficial when used with small amounts copper. another example, chromium not potent corrosion inhibitor when used alone amounts under per cent, but when added the combination phos- phorus and silicon marked improve- ment noted. Similar phenomena are obtained with nickel various combinations, particularly with cop- per. the range which the above elements can used make satis- factory high strength steel, the previ- ously mentioned formation pro- type rust coat will prevail approximately the following type compositions: Cr-Si-Cu with Cr-Ni-Cu with Mo-Si-Cu with High per high (1% per cent) combination relatively small amounts the alloying elements some steels this character provides highly protective oxide coating low cost. Increasing the amount the alloys these combinations will neither substantially nor economically improve the corrosion resistance the steel. Copper-bearing steel (0.20 per cent copper minimum) recog- nized having atmospheric cor- rosion resistance about that plain steel. The best the high strength steels have atmos- corrosion ‘resistance two three times that copper-bearing steel. Since generally not prac- tical nor desirable, for reasons economy and good charac- teristics, employ the corrosion in- hibiting elements for their maximum effect, the compositions best suited the purposes discussed which have proven atmospheric cor- rosion resistance four six times that plain carbon steel. Corrosive conditions are variable throughout the applications steel, being much more severe railroad hopper car than box car, for example. While service performance the ultimate proof, cannot had when the intended application high strength steel new one. engi- neer must, necessity, draw upon such other knowledge may hand. When one the outstanding high strength steels was introduced 1933, there was made available steel which careful testing was proven have corro- sion resistance the degree referred to; namely, four six times that plain steel, two three times cop- per-bearing steel. This was com- position whose relation copper- bearing steel, regards atmospheric corrosion resistance, was the same that existing between copper-bearing and plain steel. The question then arose the probable performance this steel railroad hopper car service for the transportation coal. Reasoning from the demonstrated comparison the corrosion resistance plain and copper-bearing steel such equipment, was concluded that the subject high strength steel wouid have corrosion resistance actual service equal times that copper-bearing steel. support the above conclusion, THE IRON AGE, June 14, 1945—63 . | | } | } q | | | | | | | | | | 7 | | = 7 7 a 7 heavy-duty truck cu. yd. capacity subjected heavy impacts from falling rocks. Body plates and framing members are corrosion resistant high strength steel. Built Six Wheels, Inc., Los Angeles. reference can made the service performance series hopper cars built with plain steel one-half each car body, and copper-bearing steel the other half. These were kept under close observation, and when finally they needed over- hauling, was found that the cop- per-bearing steel had corrosion re- sistance which provided service life per cent longer than that plain steel. other words, superi- ority the atmosphere two three times was reduced one and one-half times under the service con- ditions which these cars were sub- jected over period years. striking example the superior service life expected from corro- sion-resistant steels, when compared with ordinary carbon steel, was af- forded accident which, 1936, resulted stray slab the latter getting mixed with slabs hign strength steel, into intermediate slope sheets for hopper cars. little over six years later the nine sheets which were rolled from the stray slab failed and had replaced. The facts the case were proven tracing the material and determining its chemi- cal analysis that plain carbon steel. The high strength steel sheets this series cars are still satis- factory condition after having been service for approximately ten years. semi-trailer corrosion resistant, high strength steel weighs only 6300 yet ft. long, and has capacity 25,000 Ib. Built Herman Body Co., St. Louis. IRON AGE, June 14, 1945 factor determining thickness, the substitution high strength steel the basis strength alone not order. method for combining the two requirements suggested. The side sheets hopper car, which are ordinarily 3/16 in. thickness plain copper-bearing steel, may taken for examination. the end their useful life, they are reduced thickness such extent that the remaining steel longer has suf- ficient strength and failure cracks ap- pear. The remaining thickness not great, and 0.04 in. will used for the purposes this example. Thus, cor- rosion has removed 0.1475 in. steel from the original thickness 0.1875 (3/16). will shown later that from the standpoint strength, the high strength steel will permit re- duction weight about per cent. not necessary know what combination stresses (or ‘their actual amounts) existed the cop- per-bearing steel failure. was found occur thickness 0.04 in., the strength properties good high strength steel would permit hold out until reduced 0.03 in. thickness. Next the factor cor- rosion resistance should examined. Using the comparative factor given above for the corrosion resis- tance rate the high strength steel with respect copper-bearing steel, and applying the 0.1475 in. thick- ness removed from the copper-bearing steel, required thickness 0.0983 in. obtained. Adding this the 0.03 in. obtained from the strength calculations, gives total required thickness 0.1283 in. Admittedly this approximate approach the problem, but leads the thick- ness in. which was used sev- eral thousand hopper cars now giving satisfactory service from the stand- point life. will shown that this reduction 331/3 per cent (3/16 in. thickness reduced in.) well line with the most favorable reduction made possible strength factor alone. most important conclusion drawn from the preceding discussion that thickness reductions this order are valid only the corrosion resistance the high strength steel one and one-half times that cop- per-bearing steel hopper car ser- vice. Any ratio less than this would require the thickness increased, and thus reduce the weight saving. The corrosion attack which open-top railroad equipment sub- jected due almost entirely the pollution the air industrial areas a ‘ i 4 \, sulphur gases. This fact borne out the service history the equipment. confirmed also the proven increase approximately per cent service life obtained from copper-bearing steel compared with that plain steel. other property plain steel was affected the addition 0.20 per cent cop- per than that its degree cor- rosion resistance. Sulphur Leachings The concentrated leachings high sulphur coal are extremely damaging steel any composition. the service requirements equipment included the storage high sulphur coal open-top cars for periods days longer, these leachings would given time which concentrate and then cause greatly accelerated rate corro- sion the surfaces the steel and also piercing type corrosion points where the lumps coal came contact with the sheets. This lat- ter form corrosion would cause penetration through the sheets the cars very short time. That such condition serious factor railroad service again demon- years obtained from the sheets cars plain carbon steel, and should noted that this service life again the ratio the cor- rosion resistance factors mentioned for the two types steel re- spectively, when employed equal sections. Moreover, the best high strength steels are proving their su- perior life the ratio their added resistance atmospheric cor- rosion, when compared plain car- bon and copper-bearing steels. Thus, the ratio service life equal section plain steel, copper-bearing steel, and high strength steel re- The most highly polluted atmos- pheres are found industrial areas. Atmospheric corrosion attack much more severe these areas than rural areas. Corrosion attack ac- celerated maritime atmospheres also, but not the same extent industrial atmospheres. sup- port the findings corrosion ex- perts this country, the following excerpts from report made Hudson the Corrosion Com- mittee the British Iron Steel Institute will found interesting: “The exposure station (for test specimens) Sheffield situated the heart the industrial district and the atmosphere there very cor- rosive. this standard the corro- HIS tanker operates both sea water and brackish fresh water. After the first ten years service the entire middle body, which was constructed standard ship steel, had replaced. strength steel used the reconstruction eight years ago are still excellent con- dition. Built Federal Shipbuilding Dry Dock Co., Kearny, ° ° ° sion rates other home stations are “Other industrial atmospheres, Motherwell, Redcar and Woolwich, are only half corrosive Shef- field. Here, although the atmospheres are correctly described ‘industrial’, the actual sites were situated the fringe the industrial activity, rather than its center, zone where, frequently the case, there rapid transition from industrial plant open country. “Corrosion the marine atmos- phere Calshot was less than per cent that Sheffield. Since the specimens were exposed the edge the spit and were exposed times salt spray, may con- cluded that, although proximity the sea may lead severe corrosion certain cases, general sea saits are not corrosive the markedly acid conditions which result from severe industrial pollution the at- pounds. “It may concluded above that, rule, straight for- ward corrosion iron steel should not marked nonindus- trial atmospheres, and that the pri- mary cause severe corrosion industrial pollution.” Mechanical Properties The physical mechanical prop- erties the high strength steels may now compared with those ordi- nary structural steels which have long held prominent place the con- ome struction industries, and naturally form basis against which evaluate the performance the high strength steels. This done the accom- panying table. From engineering standpoint, the most significant physical prop- erty the subject group steels, aside from their corrosion resistance and excellent endurance strength, their high yield point. This latter property owes its importance the general design practice basing unit working stresses upon the yield point. The working unit stress deter- mined dividing the yield point factor safety. Everyday meth- ods stress analysis are not exact, they seldom include the calculation secondary stresses, the influence stress concentrations and acciden- tal overloading the structure. Long experience with ordinary steel has determined certain factor safety which produces satisfactory results. The factor varies for different classes structures, and the higher its value, the greater would appear the uncertainty the true state (CONTINUED PAGE 124) THE IRON AGE, June 1945—65 r | > le | | d- | | nt | | on 1s | ed, , ich as Plastic Coatings coatings have been use for over year connection with protection metal parts overseas shipments, was only short time ago that prominent engineering company Buffalo started test the applicability plastics the protec- tion tools, dies and gages kept the plant’s tool cribs. The resulting economies were highly satisfactory the use plastic coatings not only resulted saving critical tools from injury while the stock bins but also permitted the shipment tools ultimate consumers with as- surance protection route. Another interesting application in- stituted