The Iron Age 1942-12-31: Vol 150 Iss 27

eat complac the reality early 1942 eacetu ful War. the tide way ted, accept all the alle Victory clearly ahead. How fast travel this road depends greatly the our and foodstuffs participation scrap campaigys; ever increasing, uninterrupted purchases AETNA-STANDARD ENGINEER PESIGNERS AND BUILDERS THE STEEL, NON-FERROUS AND CHEMICAL INDUSTRIES ING CO., YOUNGSTOWN, OHIO sau Peace hes ital DECEMBER 1942 Seen = ) Ae 4 j ~ ‘ ; i $34 rough treat- rnace This shell-quenching gets very with its hot load quenched and then ip. the face all this, these fixtures The alloy our 502. This Hoskins hydrogen brazing meant primarily for small light Yet can adapted brazing carbide tips giving servic rather large cutting tools. Its heating put through the furnace manually, but conveyor can adapted. The furnace ment. acid well powered, which means fast recovery economical. For the full story, write EY HOSKINS PRODU ALLOYS THE IRO AGE under act the CHILTO yea yearly Ente North ered as sec America and class matt South America 1932 : eign $15 8, 1932, at the P. ost Office Vol. 150, No. q ¢ =< ‘ NICKEL-CHROMIUM ice at DECEMBER 31, 1942 VOL. 150, NO. VAN DEVENTER President and Editor BAUR Vice-President and General Monager e ° Managing Editor, LIPPERT News Markets Editor, ROWAN Technical Editor, OLIVER Associate Editors Art Editor, WINTERS Editorial Assistants Resident District Editors Washington Pittsburgh Washington Cleveland Detroit OSGOOD MURDOCK San Francisco Editorial Correspondents Buffalo Cincinnati FRAZAR RAYMOND KAY Boston Los Angeles HUGH SHARP JOHN McCUNE Milwaukee Birmingham SANDERSON ROY EDMONDS Toronto, Ontario St. Louis BACON Seattle ° ° ° DIX, Manager, Reader Service Advertising Staff Robert Blair, Union Bldg., Cleveland Herman, Chilton Bldg., Philadelphia Hottenstein, 1012 Otis Bldg., Chicago Raymond Kay, 2420 Cheremoya Ave., Los Angeles, Leonard, 100 East 42nd New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd St., New York 428 Park Bldg., Pittsburgh Johnson, Market Research Hayes, Production Manager. Baur, Typography and Layout. ° ° ° Member, Audit Bureau Circulations Member, Associated Business Papers Indexed the Industrial Arts Index. Pub- Thursday. Subscription Price North America, South America and Possessions, $8: Foreign, $15 year. Single copy, cents ° ° ° Owned and Published CHILTON COMPANY Executive Editorial and Offices Advertising Offices Chestnut and Sts. East 42nd St. Philadelphia, Pa. New York, N. Y. U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, GEORGE GRIFFITHS, EVERIT TERHUNE, VAN DEVENTER, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY CHARLES HEALE Vice-President Vice-President Vice-President This Week in... Editorial Technical Articles Pulverized Coal for Metallurgical Induction Heating Sprocket Hardening. 2400 Tons Sinter Per Day....... Formation Hair-Line Cracks Blast Cleaning Equipment Sulphurization with Acid Slags Effect Thorium Cast Iron New Equipment: Features Assembly Line Washington West Fatigue Cracks Dear Editor News and Markets This Industrial Week News Personals and Obituaries Machine Activity Non-Ferrous Metals Scrap Markets Iron and Steel Scrap Prices Comparison Prices Finished Steel Prices Warehouse Prices Index Advertisers Copyright. 1942. by Chilton Company (Inc.) 62-63 101 125 ° ° ° ‘ ‘ a. = Record-breaking service important Navy order, made possible Ryerson co- operation steel! “Without your assist- ance, could not have been writes the contractor—and again Ryerson teamwork scores. Cases like this—in which quick Ryerson steel-service has speeded war production —run into the thousands! While have not kept count, enough Ryerson customers are working war contracts firmly es- tablish Ryerson steel from stock vital part the war production machine. Hundreds plants war contracts are depending Ryerson for steel. impor- OFFICIAL U. S. NAVY P tant order here, too urgent wait mill production; few bars there; some strip few sheets somewhere else. multiplies into tremendous tonnage—all labeled it’s all going into tanks, planes, guns and ships beat the Axis! source pride the Ryerson or- ganization that its One Hundredth Year finds the direct line greatest service great deal satisfaction War Pro- duction Unit report: your assist- ance could not have been JOSEPH RYERSON SON, Chicago Milwaukee St. Louis Cincinnati Detroit Cleveland Buffalo Boston Philadelphia Jersey City Double Nothing 1943 NOTHER year has drawn close; the most eventful year perhaps the history our country. Certainly the most eventful year the history industry. eventful, primarily, not much because what has happened during but because the tremendous responsibilities that have been placed upon all during the past months war and because the effect the outcome the war the discharge those responsi- bilities. democracy, such ours, slow starter. The people democ- racy are not trained the goosestep. But they are fast movers when once under way. And the double quick gets nation places faster than goosestep. During this past year, our nation has made vast strides toward victory. Our output today arms, ammunition, ships and other articles war has already reached point where superior the combined pro- duction the Axis powers. During the months the coming year, will reach point where will double their output. DECEMBER 31, 1942 The war Europe and Africa will not last long after that superiority arms production can brought bear the battle fronts. When have shortly attained the same degree mechanized superiority that Germany had over France, the Allied tornado will sweep through Ger- many and her satellite countries with the same devastating speed that carried panzer divisions through France. will take longer clean the Japs, even after Tokio and Osaka and the other cities Nippon are reduced piles smoldering ruins. There will thousand islands the Pacific which will require many months service our khaki-clad vermin exterminators drive the rodents into the sea from their jungle and mountain retreats. With many our boys already overseas and many more them getting ready there, would have hardly been appropriate for have wished you, usual, Merry Christmas. But can and wish for all you the strength spirit, mind and body that will enable you face and fulfill the task that lies You men and women the metal-working industry have done splendid job 1942. know that you will meet the even larger responsibilities 1943 with equal courage and success. : * 4 J | | i Virginia Beard, smiling crane operator, one many young women making steel for Victory the Inland mills. Meet Virginia... New Inland Virginia the vanguard new “task force” the Inland mills. She one many young women who are filling the industrial ranks vacated men called the colors, and men who can used greater advantage other departments. Virginia travels her crane back and forth, she re- sponds the signals other girls—furnace operators, machinist helpers, threaders, tappers, burring machine operators—from one end the Bolt and Spike depart- ment the other, even including the shipping crew. SHEETS STRIP PILING TIN PLATE RAILS BARS B TRACK ACCESSORIES Steelmaker Inland glad that these young women are able help relieve the manpower shortage and maintain the output steel that vital the war effort. The girls learn rapidly, and are efficient and careful their work. Because the variety jobs ‘they are able perform our own mills and shops, Inland does not hesitate recommend that other companies, not already doing so, consider the em- ployment young women keep plant production top capacity for the duration. PLATES PLATE REINFORCING BARS STRUCTURALS ° ° RICHARD ENGDAHL Research Engineer, Battelle Memorial Institute, Columbus, Ohio ° ° ° industrial fuel because lies abundant deposits the very door American industry, and thus is, for large part the country, the most economical source heat energy. some applica- tions has had bow the fluid fuels, oil and gas, because they can Economy sacrificed for conve- nience and close control. However, pulverized form, coal becomes fluid fuel, and hence carries with this ease control well its inherent economy. The cost heat coal is, for most parts this country, less than that oil. Based coal having calorific value 14,000 B.t.u. per and oil 150,000 B.t.u per gal. the equivalent prices the two fuels, delivered the plant are follows: OAL solid form the basic Cost Coal Equivalent Value Oil Per Ton, Per Gal., Dollars Dollars 0.032 0.043 0.054 This tabulation shows, for ex- ample that oil costs 5c. per gal- lon, one could pay much $10 ton for coal and obtain the same amount heat per dollar. But, because coal can obtained many places for ton, dependent freight charges, the difference between that price and Pulverized Coal for Metallurgical Furnaces this paper, recently presented before the Ohio Valley section and the Open Hearth section the AIME, the author discusses the economies and advantages the use pulverized coal metallurgical furnaces and outlines some the recent research and development being carried out the adaptation pulverized coal various applications. $10 ton will pay the cost pul- verization, amortize the equipment, and have appreciable margin savings over the cost oil 5c. gal. Coal can, course, converted other fluid forms gasification, but pulverized coal costs less except when gas available by-prod- uct. Hence, some the metal- lurgical industries, pulverized coal has become almost standard fuel. the malleable casting field per cent the melting and nearly per cent the annealing are ac- complished with pulverized Fig. shows pulverized coal-fired rotary melting furnace, one the types used the malleable indus- try. 1939 was that per cent the heating processes the copper industry employed pulverized coal. Many large steel billet heating furnaces have been fired for years. Fig. shows the firing end recently modernized continuous rail heating furnace us- ing pulverized coal.* This has been pointed out modern example furnace having automatic con- trol temperature and, the ex- tent possible non-muffle fur- nace, Open Hearth Furnace These proved successful applica- tions and the advantages the pulverized-coal flame have long en- couraged attempts apply the open hearth furnace. However, ac- cumulation ash the checker- works has dogged these persistent efforts. Fine pulverization coal and ample checker space with pro- vision for collecting the ash can alleviate this trouble, but seems unavoidable that gradual accumula- tions will increase resistance the flow gases and decrease output. The recent description® open hearth furnace which re- cuperative rather than regenerative seems offer likely solution these difficulties. The amount heat transfer surface required when recuperators are used much less THE IRON AGE, December | é | wu than that with checkers. Further- more, the nature the silicon car- bide tubes makes desirable arrange for the flow gasses predominantly vertical instead horizontal. With the flow the first pass being vertically downward the top surfaces the horizontal tubes would swept clean and much the ash would thrown out centrifugal force the 180 deg. turn the bottom the first pass. The maximum temperature reached recuperators naturally much lower than that checkers. Thus, the recuperator could operate continuously temperature be- low the ash softening temperature that the ash would not become sticky and adhere. This apt occur the regenerator which reaches high temperature just before reversal the cidentally, this the only applica- tion where the accumulation ash has seriously hindered the perform- ance furnace using pulverized coal. Forging Furnaces The use pulverized coal heavy forging furnaces steadily increasing. This trend has been ac- celerated the present transpor- tation difficulties with fuel oil. modern installation for heavy forg- ing has been described Hering- However, the bulk the out- put the forging industry small forgings such drop forg- ings. for this reason that Bitu- minous Coal Research, Inc., part its program the indus- trial utilization coal, has spon- sored study Battelle very small drop forging furnace.’ This furnace, shown Fig. was loaned through the courtesy the Columbus Bolt Works and one number such furnaces now fired oil that plant. al- terations were made the furnace other than the addition hood and stack connection and enlarge- ment the burner ports. The fur- nace hearth was in. and the volume the combustion space was cu. ft. The furnace was equipped with two burners located opposite ends the chamber the same manner when oil was used. These bur- ners were offset in. horizontally order avoid direct impinge- ment the opposing flames well induce swirling flame with- the chamber. Fig. sectional view burner. pipe carrying the primary air-cooled mixture dis- charged into the throat the ven- turi-shaped burner port. The an- nular throat between the burner pipe and the port provided entry for rapidly rotating envelope secondary air; rotation duced supplying air the wind box tangentially. Wind box pres- sure was approximately in. water; furnace pressure ranged from 0.2 0.4 in. water. Usually, for convenience, gas flame was used for starting. The gas pilot consisting ameter orifice was incorporated in- the tee the coal supply line and was connected the gas main which supplies natural gas pressure per sq. in. When was desired use gas for pre- heating, the pilot could oper- 28—THE IRON AGE, December 31, 1942 ated inspirating premixing burner which could obtain air through open branch tee the coal supply line just above the burner. When coal was fired this branch was closed. The furnace has been started also building small fire wood coal the hearth and fir- ing the pulverized coal over the incandescent bed formed. When using the gas pilot for start- ing, the gas could turned off after the adjacent refractory reached 1500 deg. F., since igni- tion the coal was then self-sus- taining. disk-type feeder supplied pul- verized coal from bin the pri- mary air fan which delivered the resulting mixture through stand- ard pipe the burners. Secondary air was supplied separate blower, control which was ob- tained butterfly valve the blower inlet. Effect Coal Coals from the Elkhorn seam Kentucky, from the Sewell, Poca- hontas Nos. and and Island Creek seams West Virginia and from the Moshannon seam Penn- sylvania were used. These varied ash content from 3.5 8.0 per cent, volatile matter content from per cent, calorific value from 14,260 14,900 B.t.u. per ash softening tempera- ture from 2300 2850 deg. F., and grindability index from 110. Little difference was found among them. When firing coal pulverized per cent through 200 mesh rate end ro- tary melting fur- nace adapted pulverized coal. Courtesy Whit- ing Corp. RONT view 5-ton Brack- elsberg furnace. the extreme right. 2—Burner end continuous rail heating furnace showing the controls and firing equipment. Courtesy Amsler- Morton Co. THE IRON AGE, December 1942—29 3 q q | PRIMARY AIR-COAL SECONDARY AIR 5" type forging furnace tested IG. 4—Cross-section pulverized coal burner used the Battelle laboratory. Ib. per hr., the furnace could heated from room temperature 2300 deg. hr. After the refractory was heated thermal equilibrium, the furnace could maintained 2350 deg. when empty firing the rate per hr. With the average fur- nace temperature 2400 deg. F., load twenty in. round steel bars ft. long projecting into the furnace in., was heated 2200 the optical pyrometer. The coal- feed rate lb. per hr. How- ever, the furnace had not yet reached thermal equilibrium when this test was made. Examination the bars after removal the end the min. showed that scaling was light and that the thin deposit ash the bars fell off with the scale during handling. actual production test over four-day period was found that the furnace could supply steel rate equal that simi- lar oil-fired furnaces and with sub- stantial savings fuel costs. Distribution Pulverized Coal The disk-type feeder which was satisfactory for the tests with single furnace would not prac- ticable for supplying many burners. For such cases simpler sup- ply the coal-air mixture through pipes leading from central point. Pulverized coal when mixed with air can made flow through standard pipe over distances several thousand ft. Three classes distribution systems utilize this 30—THE IRON AGE, December 1942 property. They differ chiefly the amount air used, air pressure, velocity mixture, arangement piping, and type prime mover. They are follows: (1) Compressed air blowing system. (2) Pumping system cool-air- emulsion system. (3) Air mixture circulating system. the first two systems the mixture too dense for ignition burning. Hence, the coal supplied the pumping blowing systems usually received substation bins, from which coal fed the de- sired rate into primary air stream leading the furnace. The air mixture circulating system supplies mixture suitable for ignition the burner. The Hol- beck system, which came into wide use twenty-five years ago, out- standing example this system. Usually air and coal excess demand are supplied the mains the central fan and feeder. Por- tions this mixture are tapped off from convenient points near the furnaces fired. The excess continues around the loop and returned the storage bin. Two recent installations the circulating eliminated the usual bin and pulverized coal feed- ers supplying the coal the system directly from the pulveriz- ing mill. They are modifications the system that the unused coal not returned bin but continuously -circulated until used. The fan which supplies the laboratory forging furnace shown Fig. air the mill installed with suf- ficient capacity circulate the air- coal mixture around the loop addition. This modification intro- duces the same advantages com- pactness and control which the di- rect-firing system brought boiler- furnace practice when replaced the bin-and-feeder system. Radiant-Tube Furnace comparatively recent develop- ment metallurgical heating the gas-fired radiant-tube furnace which the fuel and products com- bustion are enclosed alloy steel refractory tubes which radiate heat the work. artificial at- mosphere any desired composi- tion can maintained the work chamber without contamination the flue gasses. The coal industry endeavoring introduce the economy coal this type furnace through de- velopment work now being done Battelle for Bituminius Coal Re- search, Inc. The experimental work mental radiant-tube furnace which was loaned for the purpose through the courtesy the Lee Wilson En- gineering Company, one principal builders radiant-tube furnaces. obtained; satisfactorily uniform tube temperature maintained; the flow gasses through the tube kept high enough sweep the fine ash out the tube. insur- difficulties peared, and after some further work coal the deve coal beco fuel ener nace | Sp work this type furnace can use coal well gas. Through this and other research the coal industry endeavoring develop and improve methods for coal utilization that coal can become more nearly our universal fuel well our basic source energy. Bibliography “Periodic Malleable Annealing Fur- naces,” presented Cleveland Meet- ing American Foundrymen’s As- sociation, April, *Herington, “Pulverized Coal,” THE IRON AGE, Vol. 143, Feb. 1939, pp. 48-50. Herington, F., “Billet Heating,” Vol. 146, Aug. 29, 1940, pp. W., Industrial Furnaces, second edition, John Wiley Sons, Inc., New York, Y., Vol. 1942, 194. H., “Proven Design for Recuperative Open Hearth Furnaces,” Industrial Heating, Vol. No. 1942, pp. 623-624. F., Coal,” Steel, Vol. 110, 1942, pp. 62-63, 98. B., and Graves, E., Coal for Forge Fur- naces,” Heat Treating and Forging, Vol. 28, 1942, pp. 327-330, 336-338. Anonymous, “Pulverized Coal for Metallurgical Furnaces,” Mimeo- graphed Bulletin published the Wilcox Co., 1942. C., “Pulverized Fuel, Colloidal Fuel, Fuel Economy and Smokeless Combustion,” the Macmil- lan Co., Chapter XI. Induction Heating Sprocket Hardening problem hardening the wearing surfaces sprocket teeth without affecting the ductility the remainder the part and speeds being solved induc- tion heating method and machine developed the Ohio Crankshaft Co., Cleveland. The Tocco unit shown being used the Cleve- land Tractor Co. the hardening heavy in. sprockets which they furnish high speed trac- tors now serving the construc- tion and maintenance military airports. The machine was built process three sprocket teeth simultaneous- ly. Using high frequency cur- rent applied the teeth only, temperature about 1500 deg. induced. This temperature maintained for only sec. and the current automatically shut off. stream water then applied for sec., providing the quench. See Fig. The cycle short that conducted heat cannot reach high enough temperature affect the balance the sprocket. auto- matic fixture setting, the sprocket moves the next three teeth into position and the cycle repeats. Great accuracy over the control the depth hardening and area heat treatment claimed for the machine. Fig. illustrates the hardened zone typical sprocket from this machine. The metal SAE 1045 steel and hardened Rockwell these sprockets, which measure in. diameter and have teeth which are in. the base, could hardened the rate only per hour. the Tocco method the hardening rate now said have improved ma- chine adapted for the hardening sprocket teeth in- duction heating. Here the water quench seen progress. Close-up view the sprocket teeth showing the hardened zone. Great accuracy and control both depth hard- ening area are claimed for the induction heating process. about sprockets per hour with the additional advantage greater precision, according Stillman, chief metallurgist the Cleveland Tractor Co. THE IRON AGE, December — » | | | 2400 Tons Sinter OMPLETION the new and modern sintering facilities recently placed operation the Campbell, Ohio, plant the Youngstown Sheet Tube Co. will increase materially the daily output the blast furnaces the Youngstown district. The new plant, which has rated daily capa- city 2400 tons sinter, integral auxiliary the Campbell blast furnace unit the company. The function this plant combine flue dust and fine ores which because their physical size are impractical for charging di- rectly into the blast furnace; then process these materials and make them coherent heating the prop- erly prepared material partial fusion point while strong air 32—THE IRON AGE, December 1942 stream passed through the mass, thereby forming air cells pockets throughout the entire mass. The particular advantage the use properly prepared sinter creased output and reduction fuel consumption the blast fur- nace plus the recovery valuable raw materials which otherwise could not used. The blast furnace larry track which carries the cars servicing the blast furnaces with necessary raw materials was extended trestle track the site the new plant. 50-ton car driven gas loco- motive delivers the ores trestle hopper. Other materials such flue dust, coke breeze and scale are delivered low level, standard gage track and placed truck hopper preparatory being proc- essed. Feeders the bottom these hoppers deliver material, proper proportions, onto gathering belt which discharges elevating belt conveyor. This elevating belt conveyor located outside the plant proper and approximately 197 ft. long. The burden from this ft. vibrating screen which re- moves all material over in. size. The trestle hopper feeder belts and the feeder belts from the track hoppers may operated separately together that ore and flue dust may blended any ratio desired, controlling amount feed from each hopper. The over size material passes IG. Bin hoppers and feeders, showing material sintered being distributed ages belt con- veyor. thro blas pass othe and plac are nor Sir chi the Per Day through chute cars and sent the open hearth furnaces the blast furnaces. The fines which pass through the screen fall an- other belt conveyor, approximately ft. long, and are discharged onto shuttle belt conveyor which above and over the storage bins. moving this shuttle conveyor back and forth the material may placed into any one the seven storage bins the inside the plant proper. These raw material storage bins are ft. diameter and have nominal capacity 450 tons each. Since there are two sintering ma- chines this plant, there sep- arate feeder system for each them opposite sides the stor- age bins; thus different grades Final mixing pre- sintered material accomplished this Youngstown Sheet Tube has completed new sinter- ing plant, materially increasing its daily blast furnace output and reducing fuel consumption. this article, the plant's operations and equipment are described detail. sinter can made the same time, different grades ma- terial may charged allowing each machine operate best speed and desired depth material the grate bars. Under each bin there revolv- ing table serving circular disk feeder driven 600 1800 adjustable speed motor. From this point the flow material independent for each sintering ma- chine. Any combination bins may placed operation, discharging their burdens upon the belt convey- ors one time. The amount ma- terial flowing from each bin con- trolled means sliding gate. Therefore, discharging from two more bins and controlling the flow material, any mixture materials with any percentage each material can obtained the sinter mix; for example, two differ- ent types ore, each combined with given proportion flue dust, which was blended the conveyor belt the trestle hoppers, can now WAS THE IRON AGE, December 1942—33 y mixed predetermined percen- tages and then combined with the desired percentage coke breeze. The belt conveyors the storage bins are in. wide and approxi- mately 185 ft. in. long. The material mixed proper proportions discharged onto an- other belt conveyor (Fig. located right angles the conveyor car- rying material from the storage bins, and deposited into hopper the primary pug mill along with screenings from the finished sinter which are known “return fines.” These “return fines” are fed out hopper, under the sinter screen the discharge end the sinter machine, magnetic vibrator conveyor. Dust which automati- cally dumped from dust col'ectors and spillage from head and dis- charge end sintering machine discharged, also, into hopper the pug mill. While the volume handled this belt conveyor small, impor- tant keep the material moving the pug mill constant propor- tion. Surges wet and dry mate- rial produce unknown factor and since the operator would unable compensate for changes, the un- controlled operation would result substandard sinter. The pug mill mixes the material delivered from the hopper, which directly above it. Water added necessary. From the pug mill, the mixed material elevated belt conveyor junction feeder 34—THE IRON AGE, December 1942 from where discharged another belt conveyor and further elevated the (Fig. where the material thoroughly mixed and final moisture tempering accomplished. This method mix- ing presintered materials makes possible produce sinter suitable any grade iron. The directly above the charging end the sintering machine, discharges the prepared material directly into swinging chute which spreads uniformly the pallets the sintering machine. The sintering machines, which are approximately ft. long with grate widths in., follow the conventional design. For each ma- chine there series pallets, each designed carry grate bars which form bed which the sinter lies. These pallets form endless carrier, driven sprocket the charging end the machine, which make continuous return system. Material which has been deposit- the slowly moving pallets the swinging chute levelled the desired depth stripping plate and then passes under ignition furnace (Fig. 3). This furnace con- sists series coke gas burners supplied with high pressure blast air, making them, literally, blow torches their functional opera- tion. the material passes along the machine, which driven ad- justable speed-motor giving vari- nace end sintering ma- chine, showing gas burner ar- rangement. per min., the suction from the draft system, consisting wind boxes located beneath the pallets, pro- duces sufficient flow air down- ward through the bed, continuing combustion. The correct mixture materials important, and the right amount carbon must supplied com- plete the sintering operation the time the material reaches the dis- charge end the machine. The carbon percentage controlled the blending varying amounts coke breeze other fuel. Ore sintered correctly must contain sufficient amount car- bon, otherwise would not possible produce the necessary combustion temperature required give satisfactory output and effici- ency. The sintering machine oper- ator has facilities for producing uniform sinter the desired hard- ness and porosity. Finished sinter discharged from the end the machine onto double deck bar screen and de- livered sinter pit (Fig. un- der open-yard crane runway where loaded 20-ton crane and grab bucket into either stand- ard gage cars ground level, into larry cars trestle track. The down-draft system consists the wind boxes which are con- nected primary dust catchers down-comers. Gasses are taken off the top and then pass through two Sirroco dust catchers and onto the Sinter stock pile which finished material de- posited over double deck bar screen. Sprays water cool sinter before trans- ported the blast furnace. the induced draft fan. The dust and return fines which are collected this system are returned the pug mill described previously. The fans which produce the draft with which this system operated have capacity 140,000 cu. ft. air per min. in. static head. these two fans driven- 1250 hp. motor 720 These fans have greater capacity than any used installations this character the present time. The motor and control room constructed closed system the interest overall economy from the maintenance standpoint. This procedure was necessary since the main electrical equipment high voltage and the air surround- ing the plant carries excessive amount abrasive dust. There are approximately mo- tors installed this plant, not in- cluding those operating the bucket crane. Formation Hair-Line work Musatti and Reg- giori, showing that the soaking alloy steels hydrogen 2200 deg. followed rapid cooling through the Ar, point results the formation internal defects simi- lar hair-line cracks, has been con- firmed the Alloy Steels Research Committee the British Iron and Steel Institute. The cracks were not found the committee speci- mens examined immediately after quenching, but only after aging period. Such defects were not ob- served when the soaking 2200 deg. was carried out vacuo nitrogen, followed water-quench- ing. The conclusions are, therefore, drawn that the cracks cannot due solely the stresses resulting from the drastic heat treatment and that hydrogen must regarded the major factor operative hair-line crack formation. Evidence was obtained that when cracks had been formed they con- tained hydrogen. Thus, result rapid heating 575 deg. F., white ferrite veins surrounded the cracks, while after similar rapid heating 1200 deg. globular carbides were observed instead. The suggestion made that the white ferrite veins are due decarbu- rization the hydrogen contained the cracks immediately after for- mation. Decarburization results the formation methane, which increasingly unstable above 1110 deg. contact with steel. Ac- equipment this plant unique that all main operating motors are controlled one central point, the sintering machine operator from the firing floor, immediately adjacent the sintering machine. This system control includes se- quence starting and stopping equipment with emergency stop push buttons throughout the entire plant. loud speaker system em- ployed for giving instructions. Cracks cordingly, rapid heating 1200 deg. results the precipitation the surfaces the crack. carbide segregation the cracks result and not the cause cracks. addition the white veins ferrite surrounding the cracks tempered specimens, quite distinct white filaments austenitic character were observed hydro- gen-treated and mens. The gradual disappearance these white filaments room temperature keeping with the view that they consist hydro- gen-rich constituent which owes its stability, any rate part, its hydrogen content. THE IRON AGE, December 1942—35 Blast Cleaning Equipment born steel shortages and the lack production facil- ities for repair parts and new equipment have emphasized the necessity for close attention the maintenance equipment all kinds which any way enter into war production. Because blast cleaning has come have such broad application many phases war production, the maintenance such equipment prevent un- necessary repair and replacement becomes increasingly important. Rapid advances have been made the improvement blast clean- ing equipment and technique re- cent years. Formerly, its use was limited almost entirely the re- moval sand from foundry cast- ings, with sand compressed air stream the abrasive. 36—THE IRON AGE, December 1942 Blast cleaning blasting the accepted term for the practice when metallic shot and grit were substituted for sand, and with the introduction equipment employing centrifugal force rather than compressed air propel the abrasive. But blast cleaning longer confined the foundry. now used extensively the heat-treat- ing department, remove scale; preliminary step plating which provides “anchor” for final finishes produced galvan- izing, metallizing, enameling; simplifying the inspection metal parts revealing surface defects before machining; testing for hardness bringing out soft spots and hardness variations; and after machining, remove burrs. BARREL chines should loaded capacity prevent excessive exposure the bar- rel surfaces the blast. This fre- quent cause un- necessary wear. Since blast cleaning longer confined the foundry, interest maintaining blast cleaning equip- ment longer centered entirely with the foundry. Other depart- ments the modern metal plant also have stake this equipment, and are affected when its perform- ance not satisfactory. all blast cleaning equipment, whether barrel, cabinet room, whether employing centrifugal force compressed air propel the abrasive, the forces that quickly clean the metal may, not proper- controlled, speed destruction the equipment also. Regular and frequent inspection necessary for the efficient opera- tion all blast cleaning equipment. Early replacement worn parts and the correction operating ills will prevent shutdowns the midst production operations. All parts the equipment the blast zone, whether blast room, barrel special blasting machine, should shielded from the abra- sive order avoid direct re- bound abrasive impingement. Sec- tions the walls blast rooms, the ends mill heads barrels, and the walls special cabinets should built with abrasive- resistant steel wearing plate. Such plates should examined regular- ly, and installed that they may changed readily when they wear through, thus preventing passage abrasive the equipment proper. Nozzles, Hose and Lines When fixed nozzles are employed machine using compressed air blast, they should installed operate without cross blast- ing, and checked insure that abrasive not rebounding from the work another nozzle and causing excessive wear. sure that noz- zles are tightly fastened their holders. Worn abrasive hose, cut nipples and fitted over nozzle jackets, affords additional protec- tion. Abrasive occasionally finds its J way and the the the gas the the fit, no: be: Care and Maintenance way between the threads the nozzle holder and the nozzle nut, and operator inclined tap the nozzle remove it. Tapping results cracking the brittle alloy nozzle insert and once cracked, the resultant wear soon terminates the life the nozzle. Special care should also exer- cised make sure that the rubber gasket makes tight joint between the base flange the nozzle and the nozzle holder. Without tight fit, abrasive will escape and cut the nozzle holder and nozzle nut, fre- quently cutting the outside the nozzle itself. Thesize abrasive used bearing nozzle life. general, finer abrasive causes the greater wear. Likewise, abrasive particles spherical shape are easier the nozzles, well hose and abra- sive lines, than irregular abrasive particles with sharp corners. The primary consideration the selec- tion abrasive should the type finish desired the cleaned piece, but often may well experiment with larger size, with steel shot sand steel grit now used. abrasive may found that less destructive the equipment without serious sacrifice cleaning speed finish. Mixing two sizes grit shot, mix- tures grit and shot, will provide variations finish. Abrasive conducting hose should installed without sharp turns kinks, permitting the bore kept full and round allow unre- stricted passage the abrasive for the full length the hose. This will minimize the possibility the abrasive cutting through the hose point restriction. Use hose with special conductive rubber tube will eliminate the building static electric charges. Such charges perforate the hose with small holes and may give workman serious jolt. Giv- ing abrasive hose quarter-turn regular intervals will markedly increase its service life. Abrasive lines should heavy ° TURNBULL Chief Engineer, American Foundry Equipment Co., Mishawaka, Ind. ° ° ° Steel scarcity has placed new meaning the impor- tance properly maintaining blast cleaning equipment prevent replacement. Likewise, broader use blast cleaning has increased the effect which would result from wholesale equipment replacement the available steel supply and parts production. The author discusses the component parts blast cleaning equipment and gives specific, practical pointers effective maintenance. steel pipe ample size prevent undue restriction the abrasive flow which would result excessive wear. Use “tee” with the un- used leg plugged has been found more satisfactory than “ell” providing cushion against wear the connection. “ell” turn, the connection receives the full force the abrasive moves through the pipe. Compressed Air One the most common sources trouble blast cleaning equip- ment moisture the compressed air. Trouble from source, when proper steps are not taken eliminate entirely, will vary with change atmospheric conditions, being more severe humid days. cooling water through the water-jacket the compressor and installation after-cooler will eliminate much the trouble. When possible, piping from the compressor should slope slightly the direction the air passage, with water trap installed catch moisture dropped from the air. Airless Machines Wheel blades centrifugal- wheel airless blast cleaning ma- chines should inspected every four hours, and oftener when un- usual vibration occurs. Badly worn and broken blades cause excessive wear the wheel plates, and along the blade slots the wheel plates. They should replaced. Blade locking screws likewise should replaced when they become worn and longer hold the blades firm- place. Blades are supplied the manu- facturer sets, matched weight within small fraction ounce. Balance wheel can main- tained replacing worn blade and the blade immediately opposite, making unnecessary replace all blades wheel. Wheel vibration indicates unbalance, and should corrected immediately prevent damage the bearings and other parts the machine. Abrasive Separators Abrasive separators, furnish cleaning agent free dirt, are finding increased favor modern blast cleaning installations. their operation, dirty abrasive from the thin curtain over inclined shed. The abrasive, flowing off the shed, passes over air duct while falling into the storage section. The air, passing through the abra- sive curtain, carries away the sand, dirt and abrasive fines into set- tling chamber, permitting only clean abrasive reach the hopper airless equipment, the com- pressed air stream for air pressure blasting. The discharge orifice the sep- arator should adjusted pro- vide even flow dirty abrasive over the shed plate Occasional checking the orifice and the perforated plate above the orifice will make possible THE IRON AGE, December 1942—37 example loading barrel type machine with extremely small pieces. The mesh cage simplifies the loading operation and prevents the small parts from damaging each other the machine during the blasting operation. eliminate any accumulated foreign material. The volume the air exhausted from the separator vent will deter- mine the amount and particle size the material removed from the abrasive stream. The size abra- sive used the cleaning operation, and the size the particles removed, will determine the maxi- mum exhaust. examination handful the material dis- charged the separator reveals grains full-size abrasive, the ex- haust too high. Likewise, similar check the abrasive flow- ing the hopper reveals dust, sand and abrasive fines, the volume air exhausted too low the ad- justment the separator should altered. Ventilation Proper ventilation essential efficient operation blast cleaning equipment. Dilution the abra- sive with sand, scale and other for- eign material not only retards the work reducing the efficiency the abrasive, but smudges the work. also speeds wear abrasive lines and hose, and nozzles-or wheels throwing the abrasive. Without proper ventilation, uncontrolled dust will escape from machine barrel, cabinet blast cleaning room into the plant, there cause wear other machinery and make working conditions hazardous. Frequent examination the abrasive before returns the airless machine’s wheel the compresed air stream, well examination the material collect- the dust collector, will afford good indication operating efficiency the ventilating system with respect the abrasive. This test will not, however, indi- cate the efficiency the dust collec- tor with respect cleaning the air passing through it. dust collec- tor’s efficiency determined not the volume material removed from the air, but the purity air released after passing through the collector media. Tests de- termine efficiency the collector are necessary where the air re- turned the plant, where ex- haust excessive amount finely divided dust particles would objectionable others the The piping system should cleaned thoroughly every two three weeks when the blast cleaning equipment served the ventilating system used eight hours day— and cleaned oftener when used high production schedules. Blast gates branch pipe lines individual blast cleaning ma- chines cabinets should periodi- checked insure proper dis- tribution exhaust capacity collection system servicing several pieces blast cleaning equipment. Excessive pipe wear from high velocities dirty air will occur necessary close any branch gate more than half way. such cases, advisable decrease the velocity partially closing the main gate the ex- haust fan. Regular inspection should include piping, with particular attention joints and connections, detect corrosion, wear damage that would result leakage; blast gates and dampers, for proper setting; collecting elements and their supports, detect wear and insure proper alinement; and exhauster, determine proper connection power source. Loading Barrel-Type Machines Care should exercised load- ing barrels and machines which the work being cleaned tumbled. partial load, the work affording protection from the blast other- wise exposed parts the barrel size and type abrasive determines the finish which blast cleaning will produce. the top row, the finishes were obtained the use shot, while the examples the lower row were produced with grit. Both types abrasive were used progressively smaller sizes produce the variety finishes shown. 38—THE IRON AGE, December 1942 j tic fo: cle | A 5 mill. Special care should taken with irregularly shaped exces- sively long pieces, such work has tendency nest. Several steps taken prevent breakage fragile parts tumbling: small pieces rubber hose will break the fall fragile castings; several pieces wired to- gether may tumbled safely where single pieces may break; the mill may slowed; and mixing heavy pieces with fragile parts should avoided. Motor Care full discussion care mo- tors powering blast cleaning equip- ment not within the province this would vary somewhat type motor installed, and specific instruc- tion sheets generally are available for each motor. However, few general maintenance suggestions applicable particularly cleaning equipment should fol- lowed. Motors are installed blast cleaning equipment the manu- facturer with due regard the load they are expected carry, and with proper consideration given con- venience inspection and repair. After equipment installed the plant, however, some these con- ditions might changed equip- ment arrangement and operation without due regard for the motor’s limitations. sure that proper ventilation the motor not prevented piling restrictive material around it. Connections should checked regularly make sure that they not become loose with equipment vibration. motors late design, there assembly operations performed conveyors often necessary turn the apparatus being assembled that can worked from both sides. case point the Westinghouse small motor division the assembly skids wooden base plates the feet small motors. expedite the work, dolly mounting turntable rolls along the side rails slat conveyor. After the motor has been placed its base plate the dolly, two nuts the base plate bolts are tightened hinged socket wrench. The assembly then re- volved the turntable, and the two nuts the opposite side are tightened. The assembly then slid off the dolly onto the conveyor. TYPICAL abrasive separator using shed plate and air blast separate the fines and ments from the abra- sive. example wear the side plate air-less machine due the rebound abrasive. greater danger over-lubrica- tion than insufficient lubrication. Excess lubricant applied bearing housings may carried into the motor, lodge the windings where catches dirt and promotes motor failure. pressed air for frequent cleaning motor air ducts damage the motor may caused blowing abrasive and metal chips into mo- tors when compressed air used. ammeter installed motors called upon for severe service will provide determination the exact load all times, lessening the danger motor burn-out. THE IRON AGE, December 1942—39 ak Desulphurization with Acid Slags LTHOUGH generally as- sumed that pig iron and steel can satisfactorily desulphurized only with basic slags, the British Iron and Coal Trades Review re- ports that Durrer and Marin- cek point out Stahl Eisen June that collaboration with Hellbrugge they have demon- strated (Archiv, 1940-41) that the use acid slags for this purpose not only feasible, but actually re- sults much lower values than those usually obtained with basic slags. This desulphurization reac- tion may described the equa- 2CO the content varying with temperature shown for six slags with increasing acidity, slag consisting pure silica. The reaction practically complete above 3090 deg. and hence the temperature, arrive the same degree desul- phurization. The effect the vol- ume slag used also investi- gated. the experimental work carried out, pig iron and synthetic slags were used, and melts made graphite crucibles with 0.1 per cent oz.) fused with fluxes and raised the required temperature either 2910 3090 deg. F., charge oz. cold pig iron was added. After about min. the ini- tial temperature drop had been re- covered, and the working tempera- ture was again reached and main- tained until the charge was poured into mold. The temperature 2910 deg. was checked with Pt/PtRh thermocouple wires suit- ably protected sealed sinter- Composition of Slags Tested Slag No. 1 2 3 4 5 6 Sio. 49.70 3.52 42.15 41.16 52.40 20.70 20.70 18.58 20.31 21.01 0.488 0.578 0.621 0.920 0.896 0.524 High temperatures thus favor the degree acid desulphurization, and other conditions being un- changed, reaction with suitably fluid slags found the more com- plete, the greater the concentration silica. With high-silica slags, temperature about 3275 deg. necessary. Increasing fluidity the slag facilitates desulphurizing, and the more viscous the slag, the slower required sulphur con- tent reached. Slag fluidity also desirable facilitate the escape silicon sulphide and CO, the gaseous products the greater the elimination these constitu- ents, the more complete the re- action. Since the normal temperature used for this reaction not high enough, either must raised the viscosity the slag reduced the addition fluxes. Good results are hence obtained where the slag hotter than the iron. The previ- ous work the authors has already elucidated the general principles desulphurizing with acid slags high temperatures, and the present paper deals more specifically with what flux additions can made the charge reduce the viscosity, 40—THE IRON AGE, December 1942 corundum sheath enclosed outer carbon sheath, while the 3090 deg. temperature was measured graphite rod immersed the charge and the base observed with radiation pyrometer calibrated 2910 deg. After adding the pig iron, the slag commences foam with the evolution combustible gas white cloud with smell Experiments 2910 deg. indi- cated that desulphurization was much improved adding fluxes, for the viscosity was diminished and the reaction accelerated. The values were, however, still too high, for initial 0.48 per cent was not reduced below 0.1 per cent NaCl, Na,CO, and only slightly improved desul- phurization owing their low melt- ing and vaporizing points. Fluor- spar gave much better results, the addition only per cent CaF al- ready giving good reaction. the other hand, the 3090 deg. melts gave much lower