The Iron Age 1939-01-19: Vol 143 Iss 3

J. H. VAN DEVENTER Editor Managing Editor News Editor Editor Emeritus Machinery Editor Art Editor Metallurgical Editor Consulting Editor Washington Editor President MOFFETT Resident District Editors Pittsburgh Chicago Cleveland Detroit Editorial Correspondents London, England Cincinnati Boston Hamburg, Germany MEYER CHARLES Post Milwaukee San Francisco Toronto, Ontario Birmingham Newark, N. J. St. Lowis TURNER, Buffalo 19, 1939 Owned and Published Cost Reductions More Needed Than Welded Continuous Rayon Spinning Machine CHILTON COMPANY Pulverized Coal for Metallurgical 4 Editorial and Publication Office Chestnut and 56th Sts., 239 West 39th St.. Coatings Philadelphia, Pa. New York, OFFICERS AND DIRECTORS Design Advances Cutters, Small Tools and Gages..... -and FRITZ FRANK, Executive Vice-President Bridgeport Brass Opens New Rolling FREDERIC STEVENS, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR Secretary Washington News isers JOHN VAN DEVENTER, JULIAN CHASE, FLM DIX, Manager Reader Service Plant Expansion and Equipment is=— Member, Audit Bureau of Circulations Member Associated Business Papers Indexed in the Industrial Arts Index. Published every Thursday. Subecrip- tion Price: United States and Pos- sessions, Mexico, Cuba, $6.00; Can- ada, $8.50; $12.00 year. abl Single copy, Cable Address, Just Between Two Emerson Findley, 621 Union Bldg., Cleveland all Herman, Chilton Chesinut 56th Sts., Philadelphia, Pa. Peirce Lewis. 72310 Woodward Ave., Detroit de- Warren, Box 81, Hartford, Conn. Copyright 1939 Chilton Company | a y rge 5 These are but few the many stories that come every day, proving the advantages using Ryerson Certified Steels. Since this higher uniform quality can purchased without increased cost, believe will pay you concen- trate with Ryerson. Remember the steel stock and Im- mediate Shipment assured. Joseph Ryerson Son, Inc. Plants at: Chicago, Milwaukee, St. Louis, Boston, Detroit, Cincinnati, Cleveland, Buffalo, Philadelphia, Jersey City. 18—THE IRON AGE, January 19, 1939 ... THE IRON AGE ... JANUARY 19, 1939 Vol. 143, No. Cost Reductions More Needed Than Armamen OW, are considering plan preserve peace earth and make the world safe for democracy arming America the The thought behind this that have enough battleships and guns and airplanes and ammunition, nobody will want start trouble for fear that will drawn into and that would undoubtedly win. this program goes through, will mean keeping large part our best and most modern machine equipment tied war material production for months years come. And will also mean discarding good part our present mechanical equip- ment and replacing with up-to-date machinery, since you cannot turn out satisfactory war products with anything but the best. This same high-class production equipment could, course, remarkable job cost reduction—and price reduction—on behalf America and other consumers were applied making needed peace-time products. per cent reduction the prices the things have buy better than per cent increase the individual incomes the people who have buy things, from the standpoint public welfare. Applied munitions making, this same equipment will double-barreled cost and price increaser. First, because its cost and operation expense must met the public and, second, because wholesale diversion skill and energy war production will inevitably increase the cost and price peace products. Germany's people must paying dearly indeed, this respect, for the mainte- nance 500,000 workers military aircraft production—more than employ the automobile industry the United States. And Germany has working population but third ours. How long can nation keep multiplying this non-productive overhead? Per- haps after you once start armament race, the only way avoid bankruptcy gamble conquest. are told that the capacity country produce munitions quickly when needed more important than existing supply war materials. so, would not the best armament program for consist National policy encouraging indus- trial plant modernization? war then became imminent, would find ourselves able meet it; did not, would have made splendid self-liquidating, price reducing investment behalf the public. 7 ISHED ~ 4 a 4 J 7 ¥ CUTTING MACHINING COSTS, Time money when racing car roars over the track against the field, speeding for the cash prizes. Time money, too, when machine tools work with highest efficiency competing against those every other manufac- turer. new advantage now available, enabling you produce machined steel parts greatly increased speeds. Or, you can use steels with higher physical properties increase machining time cost. HOW change equipment any methods operation required. You merely substitute Inland Ledloy proper open hearth analysis for the steel you are now using—then machine from 30% more than 100% faster than the practical limits ordinary steel similar analysis. Inland Ledloy the new lead-bearing steel developed last year the metallurgical research laboratories the Inland INLAND LED INLAND PRODUCTS FLOOR PLATES INCLUDE: STRUCTURALS SHEETS PILING RAILS STRIP TRACK ACCESSORIES Steel Company. contains very small amount lead evenly dispersed the steel with measurable change physical properties. EXAMPLES SAVINGS Many parts makers have been using Inland Ledloy for months, with such cost-saving results the following: forging company saved 30¢ per crankshaft produced. automobile parts manufacturer reduced machining time equipment manufacturer increased machining production from 918 1,330 parts per hour. Savings range from few dollars more than $50 per ton Inland Ledloy used. Order trial lot Inland Ledloy today, hot rolled form through your nearest Inland office, cold finished from your regular supplier cold finished INLAND STEEL COMPANY, South Dearborn Street, Chicago. TIN PLATE BARS PLATES REINFORCING BARS i 3 —— \ —— Ss Yyy . q == Continuous Rayon Spinning Machine Welded Steel Construction 14-acre plant Painesville, Ohio, has started operations with the world’s first commercial installation equipment for the continuous spinning, processing, drying and twisting vis- cose rayon yarn for woven fabrics. Seven nine heretofore independ- ent operations are combined single machine, the co-ordination made genious, highly developed reel com- posed chemically resistant molded plastic members, and the use arc welded steel members and light weight metal closures throughout the required for the composite machines. The high degree accu- racy and rigidity required maintain perfect alinement hundreds mov- ing parts was obtained with maximum Mr. Bergmann and MacDonald, de- Signing engineer, American Bridge Co., Pitts- urgh, were co-authors per Supporting Structures for Continuous Process Rayon Producing Machines” which the Fourth Award the James Welding Foundation competition the Industry Machinery classification. NDUSTRIAL RAYON fe) BERGMANN* Chief Engineer, Rayon Machinery Cleveland, Ohio economy through unusual jig welding procedure. the initial processing, cellulose fibre sheets are dissolved series controlled chemical baths form liquid rayon viscose, which piped the spinning room. This liquid rayon forced through the minute holes jet spinneret submerged the acid bath lead lined, glass- enclosed spin tanks the top each machine. The machines are three tiers high, operations starting the top and continuing downward. Fig. shows machine during installation and Fig. shows the spin tank. The viscose coagulates leaving the jet and entering the bath, each hole producing separate and distinct filament the yarn all rayon manufacture. Instead being wound directly into package and treated through successive operations such form, the yarn bleached, treated and dried continuous thread advancing reels, and twisted wound the bobbin. Unlike other reels designed for this comparable purposes, each reel these continuous machines made two cages slat pulleys, set one within the other, and rotated overhung assembly. motion they assume the appearance cylinder, but the two members the reel not rotate about the same center. The relation the cages each other causes thread led onto the reel one end advance along the bars automatically the reel rotates, until the thread passes off the outboard and down the next reel the sequence. Moving through processing liquids sprayed the yarn advances the reels, the rayon thus treated single thread winding each reel has uniformity fineness and physical characteristics standards otherwise attainable. Ob- viously, also, material handling costs and production inter- ruptions are minimized. The most logical arrangement combining the rayon spinning and processing stages was superimpose them, for reasons compactness and economy floor space, ease threading when starting resuming operations any position, and for the convenient application the transmission equipment for driving the various operating mechanisms. accommodate this general plan, THE IRON AGE, January 19, | ( | : + for ced, ime tion Y 4 1 ABOVE 2—Looking into one the glass enclosed, lead-lined spin tanks the top the machine, show- ing the spinning reels which wound the rayon formed the tank. Reels are special design. Four angle take-offs for the spin- ning reels, two each side, are provided each transmission unit. S LEFT continuous spinning ma- chines, completely welded, during installation. Work- gear pump which will serve each the 100 spinning machine. Reels have not yet been installed the panels. Workman the left removing the panel which encloses the cap twister drive. The principal transmission unit driving all the spinning and processing reels mounted the top the A-frame. 22—THE IRON AGE, January 1939 — - ‘ ay 4 q ¢ shaped structure, symmetrical about the vertical center line and with three operating levels, was developed. common spin trough serves spin- ning jets pivoted from aprons both ‘sides. This permits the narrowest and lightest frame believed practical. From this width the machine builds out due the stepped panels each side, the width required the number reels vertical line complete the processing and drying. The width the bottom the panels determines the width the twisting machine, where the finished yarn wound onto bobbins. Preliminary studies revealed that fabricated and welded steel offered the greatest possibilities for eco- nomical machine frame. The design shown Fig. was adopted after thorough analysis all recommenda- tions and figures submitted num- ber representative fabricators. The basic design for jig welded structural steel frames and panels was applied under contract with the American Bridge Co., whose engineers collaborated with those the Rayon Machinery Corp. further develop and perfect the design and the neces- sary fabricating jigs and equipment for accurate checking the finished work. Every effort was made utilize easily obtainable, commercially rolled structural steel sections, well conventional fabricating facilities for the preparation the elements mak- ing the completed parts. Moreover, since the contract covered great num- bers like parts, heavy, rigid, per- manent jigs were designed and built which the parts the frame mem- bers were assembled and accurately held while being welded together. The intention the design was avoid any machining surfaces after the assembly was welded together and removed from the jigs. The extensive use flanged bearing housings and adjustably which were alined and doweled erection, eliminated much the ma- chining originally thought necessary. Except three parts, the required accuracy was obtained production without resorting machining after welding. Much skepticism had been expressed the practicability securing the required accuracy jig welding methods. Many felt that distortions caused the welding would produce inaccuracies after the pieces were re- = 3—The welded A-frame, arrangement drives and process ponels, are shown this picture. the very top the drive for the spinning reels, which are driven from single shaft. top the are the drive shafts for the processing and drying moved from the jigs, particularly the stepped panels for the processing reels. The accuracy and efficiency the jigs and production methods were checked with experimental sample parts, and with only nominal changes these parts have now all been pro- duced multiple, demonstrating that the distortions caused welding were not sufficient magnitude inter- fere with securing the desired accu- racy, owing the production methods used. The drive end A-frames and similar intermediate frames are made bent column sections milled bottom ends and flame-cut angle top ends. Bearing plates were carefully pressed and straightened and jig drilled. Ail parts were assembled jig having fixtures for holding properly position. The machinery boxes for the drive end A-frames were made com- mercial plates, bars and rounds, as- sembled jig and welded. All boring and spot facing was done one setup horizontal boring mill. Pads were also milled, establish THE IRON AGE, January 1939—23 3" w sh ip 1g accurate gage points for supporting the box the A-frame jig, which the finished box was then welded the A-frame. All elements composing the inclined stepped panels were fabricated from commercially rolled plates shapes, except the stamped and counterbored cups which the flanged process and drying reel mounts are fitted. Accu- rate alinement these cups was necessary for the proper operation the bevel gears which drive the reels from inclined shaft serving each vertical position series reels. Parts were assembled consecutive order the welding jig, with auxili- ary fixtures holding all parts accurate positions. These parts were then welded form complete frame from which the cups were entirely free, the cups being firmly attached plugs the jig base. Accurate alinement cups, after welding the frame, was confirmed inspection all panels after com- pletion, special facilities having been designed produce marked templet the exact location the axis each cup counterbore. machin- 24—-THE IRON AGE, January 19, 1939 LEFT 4—The oper- ator placing stainless steel cap twister over empty bobbin the machine. BELOW silent chain drive and cam mechanism for operating trav- erse table for cap twisters the base the machine. ing the panels after assembling and welding was necessary. The drive panel for the spin and process drive machinery was made structural plates and bars, pre-fab- ricated and welded jig. For the desired accuracy assembling the several mechanical units this frame member, the fabricator elected ma- chine the pads and base after the panel was removed from the welding jig. The intermediate for the spin machine were made structural shapes and plates, pre-fabricated and welded assembling jig. ma- chining other fabrication was necessary after removal from the jig. While the miscellaneous parts, such floor supporting brackets and frames, spin aprons, twister cylinder frames, circulating pump bases and liquor feed box frames offer un- usual features, they are interesting examples economical welded steel construction, making effective use ordinary sheets, plates, bars and shapes. Catwalks for operators the top spin machine are cantilevered from the frame members. The construction light, economical and simple, but substantial. The floor frame and grating for the operators second deck process section the machines supported brackets at- tached the A-frame columns. The Painesville installation consists i 4 > table made illustrated, with light, welded steel beams and welded tubing for pulley supporting brackets, held minimum, important advantage its operation, since traverses ver- tically for winding yarn onto the bobbins. Sheet steel closures and guards pro- vide finished appearance the ma- chines, well safety operators and maintenance mechanics. Design treatment conforms with modern prac- tice throughout. For the spin bath, processing sections, and cabinets serv- ing the drying reels, impressive total sheet aluminum fabrication was also involved. Welded steel tubing also came for generous use some the ma- BELOW the continuous spinning chine developed Industrial Rayon Corp. The operator checking flow hot water through dryer reels the base the proc- essing section. Water supply and return manifolds are shown below the snap-on closures concealing the reel gears. 6—Closeup view gears for the processing reels. we including the structure for the process liquor distribution system which mounted between machines. Fig. shows the basic framing, with drive units applied. The total over-all length the complete frame structure, the machines were set lengthwise, would 4500 feet. Another important application fabricated and welded steel members was developed the twister traverse tables. Each machine has such tables, supporting 100 rayon twisting spindles, and the required pulleys for leading the driving tapes belts and from the spindles and over the main driving cylinders. Each series tables, about feet long over-all, counterweighted and suspended pulleys and chains from longitudinal rocker shafts operated from cam the drive end the machines. The weight the j THE IRON AGE, January 19, ‘ 2 ABOVE 1G. through one the second-tier chine elements. The most outstanding example the twister cap, made en- tirely welded steel tubing with stainless skirts, illustrated Fig. Motors are flange mounted cas- ings for duplex back type silent chain drives the several elements served each motor. Chain tensions are maintained spring-backed auto- matic idlers mounted studs set the casings. Force feed lubrication from oil sump the bottom each casing provided for all chain drives, details which are shown Fig. The installation also included many special worm and helical gear trans- missions, for the distribution power each system reels. Several thou- sand gear boxes were required for driving each series reels from the main line shafting through the ma- chines. Fig. shows the gears for the processing reels. Reel gears are concealed snap-on closures shown Fig. processing aisles Painesville. was ground and polished, and straightened ances which prevented runout spiral and bevel gears. all, the installation represents probably the most general use diversified line steel products found any recent Modern design, fabricating, welding and production methods are accredited with much the commercial possi- bilities now recognized and put into effect. welded ladles re- cently made the Beth- lehem Steel Co.'s Bethlehem plant shown emerging from heat treating furnace. ow i Vv IRON AGE, January 19, 1939 7 ULVERIZED coal fuel has advantages for various kinds Therefore, view the constant de- mand for increased economies in- dustrial furnace heating, most desirable have proper appraisal industrial fuels that intelligent selection the most appropriate source heat energy for given ser- vice may readily made. Many industrial operations are initi- ated completed the burning gas, fuel oil coal. Without question the current cost fuel important, but also importance the question long range availability and the de- pendability coal low-cost source supply. Most furnaces may proper- ! / “a | ° ° HERINGTON Engineer, Amsler-Morton Co., Pittsburgh ° ° firing metallurgical fur- naces, pulverized coal went through its heyday 1915-25. The many difficulties that pe- riod resulted from inexperience, but persistent engineering has lifted efficiency that the fuel warrants careful consideration for new revamped furnace in- stallations. adapted utilize pulverized coal efficiently and when the coal prop- erly distributed for burning the fur- nace, becomes very desirable Motor Bowl Burner Primary air exhauster PLAN AIR FURNACE Raw coal Adjustable burner LONGITUDINAL SECTION THROUGH AIR FURNACE storage bin industrial fuel. ideal luminous flame produced which surpasses efficiency many other fuels. The early use pulverized coal was accompanied problems long since solved, such (1) incomplete drying the coal, (2) poor pulveri- zation, (3) lack suitable burners, (4) improper furnace design, (5). faulty methods distribution, and (6) lack dependable preparatory machinery. Within the past ten years, all these difficulties have been minimized. The new and rapidly in- creasing use and interest this fuel indication that pulverized coal reliable any fuel. The earliest use pulverized coal was the cement industry, and Raw coal bin -Grizzly Ladder line system for malleable iron melting furnace, with separate air blower for the pulverized coal. THE IRON AGE, January 19, ig ‘ > — ‘Manhole reea bin 3 heater Coal feeder Loal conveying fan aH. Fulvenzing mill t Mil! motor ~] | 9-70) | Electrically controlled aur operated valve Bin vent pipe. Separator Coal conveying fan Primary air level Primary air pipe with coal Fic. 2—A combination central and unit system for utilizing pulverized coal. Messrs. Hurry and Seaman are en- titled the credit 1895 establish- ing pulverized coal fuel the Atlas Portland Cement Co., Hudson, Its use has never been discon- tinued that plant. Today, practical- per cent the cement made this country fired with this type fuel. Because, its inception, the cement industry jealously guarded the proc- manufacture valuable secrets, was not until about 1900 that the procedure burning pulverized coal became generally known. the earlier stages furnishing pulverized coal equipment, was claimed that the proper way measure other words, for furnace performing certain heating operation using gal. fuel oil per hr., each gallon oil containing there would consumed 2,800,000 B.t.u. energy. such basis would re- coal perform the same operation, the superior efficiency the coal arising from the fact that the 2,800,- 000 B.t.u. oil would cost more than the same number B.t.u. This fact obvious, for fuel oil costs 5c. coal (with 14,000 per Ib.) would have sold $10 ton give equivalent cost per B.t.u. But this type comparison does not any means measure the ef- ficiencies metallurgical furnaces, for the real problem one heating cost and not fuel cost. Pulverized coal, any other fuel substitution for what now use, should not chosen for the mere reason that has 28—THE IRON AGE, January lower B.t.u. cost, but, rather should selected which, all things considered, will show the lowest pro- duction cost under existing conditions the shop being investigated. Production costs depend upon three things—the input, the output and the operator—and two shops are these three conditions similar. Each shop requires separate study de- termine which fuel will perform with greatest efficiency certain heating operations. order determine heating fur- nace efficiency with new fuel com- parsion with previous fuel, the fol- lowing observations should made: Start the furnace room tempera- ture, raise certain final tem- perature and note the comparative times for traversing this temperature interval for both fuels. Then take the furnace, the tem- perature the room, and place there- the charge material the same temperature, and raise both the fur- nace and the charge certain final temperature. Note the time consumed this operation for the two fuels be- ing investigated. Lastly, start the charged furnace the temperature the room (or any desired temperature) and operate the furnace the regular manner. Note how many pounds material are raised predetermined temperature and the number pounds coal, oil the amount -gas consumed order reach this figure. Unless the new fuel shows better results these three tests, not tried out this manner, does not pro- duce effects superior formerly used, not more efficient. Type Installation this point the question will arise the reasons why pulverized coal not more generally applied, especial- view the fact that its use boiler firing constantly increasing. During the years 1915 1925, pul- verized coal was used extensively chiefly because proved much cheaper fuel per ton output than any other fuel use that time. This fuel was used the ing operations: Annealing ovens, bar heating furnaces, box sheet annealing, car wheel furnaces, anode furnaces, bolt and nut furnaces, billet furnaces, air furnaces, bloom furnaces, con- tinuous furnaces, copper naces, copper reverberatory furnaces, open hearths, shovel welding furnaces, wheel heating furnaces, naces, rivet making furnaces, tire heat- ing furnaces, zinc furnaces, rotary coal dryers, and tin smelting furnaces. The source most the difficul- ties encountered during the 1915-1925 period lay the fact that many equip- ment manufacturers scrambled in- stall pulverized coal furnaces and reduce fuel costs, without understand- ing even the fundamentals the heat- ing operations involved the substi- tution the fuels. most cases the equipment was sold and delivered the purchaser and left for him erect and place successful operation. True, supervising engineer was fur- nished erect the equipment and an- other engineer start the equipment, both whom had the opportunity | \ | W W hi 29 ‘uels ient. irise coal sing. pul- inds, nuch than This heat- bar ling, aces, aces, con- fur- fur- heat- coal -1925 oO in- and heat- ubsti- the erect ation. fur- yment, 3—Pulverized coal twin screw feeder. learn with the purchaser what was all about. This practice gradually tended eliminate the problems aris- ing from inexperience. The ash problem first seemed obstacle. One estimated that with coal containing per cent ash and with his annual coal tonnage replacing fuel oil, would only period ten years before the city’s streets deposit ashes in. deep. While true that about per cent the non-organic solids the coal are discharged through the stack also true that these solids will such small size, because the pul- verization, that they will carried miles away from the stack even still atmosphere. This fly-ash white light gray and free from unburned carbon, and will not any more detrimental than the many tons dust normally car- ried around the cleanest atmosphere. The best evidence the lack ash trouble found Ford’s power plant River Rouge, where 1800 tons pulverized coal are consumed every hr. day. this coal contains per cent ash, there would deposited about one-fourth the ash content the coal leaving the stacks, about tons ash each day. However, careful observations made within radius miles have failed reveal any ash deposit. Also Cleveland, all the public utility power plants coal and there has been serious complaint ash nuisance far can learned. dust fall 1000 tons per square mile per year seems large, yet would take 100 years build deposit one inch. there have been many discussions the detri- ment the ash falling and sticking the charge material, and this point was well taken the earlier uses pul- verized coal because one knew how eliminate the nuisance. course few years ago the question supplying pulverized coal copper refining furnace was delayed for fear ash depositing copper bath containing 99.95 per cent Cu. burn- was designed that delivered the fuel such velocity that the ash particles were carried distance ft. over the bath and deposited the uptake the waste gas boiler. This burner was not complicated design —it consisting only round pipe flattened out the discharge end. Different Systems Original pulverized coal firing sys- tems may designated falling into two groups, the central system and the unit system. The central system consists four divisions, (1) the receiving, crushing, and conveying the raw coal, (2) the drying, pulverization, and storage the pulverized coal, (3) the delivery the coal the furnaces, and (4) the firing equipment. this system all the first three divisions the work are carried out building called the central coal plant. This plant placed control oper- ator who made responsible for fur- nishing the fuel required for all the heating operations. unit system eliminates the cen- tral coal plant and requires the de- livery the raw coal from the point supply each the furnaces. the furnace unit pulverizers are placed which grind and deliver the coal di- rectly into the furnace each the furnaces. The main disadvantages the unit system are: (1) difficulty maintain- ing uniform fire due variations the amount coal delivered and the pulverizer, and especially the variable fineness pulverization, (2) absence fuel storage, and (3) fur- nace delays due mechanical elec- trical trouble. This system has place where continuous heating required, where fluctuations the amount coal are necessary because varia- tions tonnages handled the fur- nace. lowering coal volume re- sults excess primary air and causes very lean mixture which turn produces unstable flame. the amount primary air cut down give richer mixture lighter loads the velocity may fall the point where the flame will work back into the burner coal may lodge the pipe. With the unit system, there also required complete duplication parts each point application and the added inconvenience raw coal (CONTINUED PAGE 57) THE IRON AGE, January 19, 1939—29 / \ | fj ‘ J} it \ / \ / it 7 ni | € 7 GALVANIZED COATINGS ATISFACTORY methods, date, have not been developed measure the weight formity coating hot dip gal- vanized castings forgings. The A.S.T.M. Standard Method, specifically states its use for galva- nized iron steel sheets and wire. director and test engineer respec- tively, Ohio Brass Co., Mansfield, Ohio. Methods Determining Weight and Uniformity Coating Zinc-Coated (Gal- vanized) Steel Articles, Designation: A90-33, American Society for Testing Materials, 1936, Part 397. 30—THE IRON AGE, Januray 19, 1939 ° This method describes stripping tests which are supposed suitable for testing zinc coated articles and which have been found unsatisfactory for hot dip galvanized castings and forg- ings. review the subject quickly, con- sider that hot dip galvanizing refers coat zinc metals. Clean metals are immersed bath molten zinc, temperature approxi- mately 100 deg. above the melting data given this paper are termine satisfactory methods for mea. suring weight and uniformity hot galvanized coatings castings and forgings. number existing meth. ods were investigated, keeping mind the need practical test which could performed the field and factory. Due the fact that was found impractical control the weight and uniformity coating hot dip galvanized castings and ings intricate shapes, effort was turned develop the use uni- formity test supplement visual inspection. The Preece test, after refinement and standardizing ma- nipulation, was found the most practical test available, for check uniformity coating. point zinc, allowed reach the temperature the bath then withdrawn. continuous film zine retained the surfaces the arti- les. The thickness coatings de- pendent upon the temperature the galvanizing bath and upon the method used remove the excess zinc. Ma- terial which galvanized the hand dip method will have thicker coat than galvanized the centrifuge method. Some shapes not lend Objects having such ular shapes these through many galvanizing plants. impractical control the weight and uniformity the zinc coatings work this ° ° re i ‘ liq cle the then zine arti- de- the thod Ma- coat fuge lend RIGHT 2—Steel forg- ing hot dip gal- vanized centri- fuge method (left) and hand dip Micrographs 500 diameters after etch- ing with cent iodine. Arrow indicates coating thickness and (b) the base steel. themselves the hand dip method and are therefore handled basket centrifuge machine methods. Uniformity coating depends upon the method used liquid zine the surface the arti- cle before solidification. some ex- tent, uniformity affected the design article: for instance, the zinc coat will thinner sharp corners and small radii than flat uniform surfaces. A.S.T.M. Tentative Specification, places minimum limit the weight coating gray iron, malleable iron and steel castings oz. per sq. ft. and 1.85 oz. per sq. ft. for rolled, pressed and forged articles. The author’s expe- rience has been that the weight and uniformity coating, for such arti- Specifications for Zinc Coating (Hot Dip) Hardware and Fastenings, Desig- nation: A153-33T, American Society for Test- ing Materials, Tentative Standards, 1936, 185. Rawdon, “Structure Commercial Zine Proceedings, A.S.T.M., Vol. 18, Part I, p. 216 (1918). Finkeldey, “The Microstructure Zinc Coatings”, Proceedings, A.S.T.M., Vol. 26, Part II, 304 (1926). Farnsworth, Observations the Outdoor Atmospheric Corrosion Protective Coat- Proceedings, A.S.T.M., Vol. 30, Part IT, 456 (1930). Kenworthy, “The Methods Testing Metals, Vol. 1937, 225. cles irregular shape, cannot controlled practical manufacturing processes. See Fig. for examples shapes. cross-section hot dip galva- nized coating will reveal complex structure when examined under Next the iron base material will found layer zinc- iron alloy over which can seen layer zinc conforming the com- position the galvanizing bath. Figs. and show typical details struc- ture may found hot dip galvanized coatings malleable iron castings and steel forgings. These metallographic specimens were moun- ted pure zine for polishing. The base metal, marked the bottom the photomicrographs and the thickness coating indicated the arrows. The alloy layers the sections shown these micro- graphs are divided into from two four distinct layers. Carefully controlled have shown that the life coatings atmospheric exposure totally de- pendent upon the weight coating, including the alloy layer. has also been shown that coatings zinc afford two kinds protection ferrous materials, (1) seal from the weather continuous envelope LEFT 3—Malleable iron casting hot dip galvanized hand dip (left) and centrifuge (right) methods. Micro- graphs 500 diam- eters after etching with one per cent iodine. Arrows indi- cate coating thick- ness and (b) base iron. metal, and (2) resistance the corrosion small bare areas due either the products corrosion the nearby zinc electro-chemi- cal protection. Fig. shows view the Ohio Brass Co. atmospheric exposure rack located the roof three story building industrial community and near crossing two main line railroads. the near end the rack are many specimens hot dip galvanized castings and forgings which have been continuously exposed for more than years and not show the corrosion exposed iron. Testing Methods desirable know the thickness measure its protective value. Where practical control the thickness, such sheet and wire, the con- sumer charged for this added pro- tection and should have some means checking the quality his purchase. survey the existing methods for determining the weight zinc coatings’ materials leads the conclusion that there are satisfac- tory test methods for hot dip galva- nized castings and forgings intri- cate shapes. The average weight THE IRON AGE, January 19, org- was ae) £ js on : > coating can determined such material during the process manufacture the investigator has the patience calculate measure the surface area over which the distributed. There distinct need for some sort indestructive which does not require the use trained operator. Uniformity tests are desirable measure the quality the protec tive coat. Quality also checked inspection. Castings which have shrinks and cracks near the sur- face and castings which are not clean will not cover the galvanizing process, and can easily detected. Abnormal variations thickness coat can segregated visual in- spection. The determination uniformity measure the thinnest parts the coating article. Uniformity usually measured stripping the coat and measuring the time when the base metal exposed the thinnest places. Chemical methods dissolv- ing the coating are not satisfactory for coatings composed different 32—THE IRON AGE, Januray 19, 1939 alloy layers because the rates dis solution vary. the authors’ experience with hot dip galvanized castings atmospheric exposure, any material which can pass visual inspection will unquestionably possess satisfactory weight and uni- formity coating. study weight and uniformity coating has been made castings hot dip galvanized both the hand and centrifuge methods. The weight coating was determined careful Number specimens i hoe. Atmos- pheric rack for the long- time testing gal- vanized coatings com- munity. Some speci- mens the near end, hot dipped castings ings, show corro- sion exposed iron after continuous posure years. ROLE! made the galvaniz- weight measurements specimens before and after termined from micrometer measurements numerous specimens. resume the data given Table The key letters the sample numbers indicate coating procedure, that (a) hand dip, cast; (b) hand dip, (c) centrifuge, cast. The measured the last two groups many coating ° ° 5—Frequency distribution the measurements coating weights many hot dip vanized castings. Weight coat,oz. per sa. : ar ncy the specimens because their intricate influence” the malleable iron around shapes. the plugs, 1/16 3/32 in. Fig. indicates graphically the fre- ALUMINUM: quency distribution the data Surface the plugs very slightly de- Table after excluding the data pressed below the level the iron the 100 specimens galvanized surface. Products corrosion the centrifuge method. aluminum plugs are dark Variation Protection PLATE CADMIUM: Surface plugs about level with the surface the iron plate. Plugs were discolored. Ring influence the iron around the plugs, 1/32 1/16 in. NICKEL: Surface the plugs about level with has Galvanized Steel Plate; Galvanized Malleable Galvanized Malleable has long been known that zine Steel Plugs Iron; Malleable Plugs Machined; Malleable affords different kind protection Plugs iron when intimate contact with This protection explained the difference solution pressure be- tween the metals electrolyte. The metal having the greater solution pressure will dissolve first within limits, prevent corrosion the other metal. Many investigators have demonstrated this protective action metals but, far the authors know, none has measured the extent the influence. This quality hot dip galvanized coatings malleable iron and steel which have been subjected heen noticed. Many experiments have formed attempt determine the limiting area bare iron which will not rust when the adjacent protective coating zine applied the hot dip method. The relative protective value the various common metals with respect malleable iron was first in- vestigated. Bare malleable iron drilled with series holes the centerline their length and plugged with various commercially pure metals the electrochemical series. size the holes and plugs began in. diameter and decreased size 4 q IG. 6—To study the protective value zinc coating for various areas exposed diameter. Periodic inspections were iron, these three galvanized plates were drilled with different size holes, and these made during atmospheric exposure test 536 days. Since very show the extent corro- made describe their appearance. PLATE MAGNESIUM: Surface plugs depressed below the level the iron. Severe corrosion the magnesium plugs. Ring There visible evidence pro tection the iron. face the plugs very slightly pressed below the level the iron plate. Plugs were discolored. Ring Ring influence means apparent resis- influence the iron around the plugs, tance corrosion the malleable iron coupon around the metal plug. 1/16 TABLE Weight and Uniformity Galvanizing Castings Average Surface Weight Coating, Thickness Coating Sample No. Area, Sq. Ft. per Sq. Ft. Side, Inch. Max. Min. Ave. Max. Min. Ave. 0.3134 640 4.19 0.0039 0.0069 0.3036 0.0090 0.0050 0.0076 100 0.214 3.26 0.035 2.33 1.48 1.89 holes plugged tightly with the base metal. The showed that corrosion unlikely exposed areas not exceed the equivalent circle. the surface the iron plate. Plugs were discolored. ring influence the iron about the plugs. the plugs slightly higher than sur- face the iron plate. Plugs were dis- colored. ring influence the face the in. diameter and the in. diameter plugs are about 1/64 in. higher than the surface the iron plate. The remainder the plugs are approximately level with the sur- face the iron plate. Plugs were ring influence about the plugs the iron. PLATE PLUGGED Copper: Sur- face the plugs about level with the THE IRON AGE, January the ter 4 d on ‘he of surface the iron plate. Plugs were discolored. ring influence about the plugs the iron. Surface the plugs about level with the surface the iron plate. Plugs were discolored. ring influence about the plugs the iron. These tests demonstrated that mag- nesium, zinc and cadmium offer pro- tection bare malleable iron when intimate contact with it. The ring influence about plugs offering pro- tection the iron wider the lower side the plugs (plate exposed angle deg. from the horizontal) which suggests that some protection may have been afforded the products corrosion the plugs. study the limiting area which hot dip galvanized coating will protect bare areas malleable iron and steel, many experiments were conducted. Malleable iron and mild steel plates were used for these studies. These plates were hot dip galvanized the hand method commercial galvanizing tank and bare areas iron exposed three dif- ferent methods. Specially ground drills, from No. in. diameter, were prepared that the bottom the holes would flat instead conical. Holes were drilled thru the depth just exposing the iron. The plates were periodically inspected during atmos- pheric exposure and the observations the end 307 days are recorded the following paragraphs. PLATE No. as-cast, galvanized malleable iron. Bare iron exposed holes No. 60, 3/32 in. and in. diameter show only very light corrosion the form dark stain tarnish. Iron exposed holes 5/32 in., 3/16 in., 7/32 in. and in. diameter show heavy red oxide the center surrounded ring dark tarnish. The area the heavy red oxide increases with the diameter the bare iron exposed. No. as-cast, galvanized malleable iron. Bare iron exposed holes No. and 1/16in. diameter show heavy red iron oxide and all larger holes show varying degrees rust No. plate. No. 14, machined malleable iron galvanized. Same plate Factors Affecting the Preece Test for Zinc Coat- ings”, Proceedings, Am. Soc. Testing Mats., Vol. 32, Part II, 453 (1932). Test for Zinc Bureau Standards Research, Vol. 12, No. June, 1934, p. 786. 34—THE IRON AGE, January 19, 1939 except that red iron oxide deposits are heavier. The evidence revealed plates was promising but somewhat irregular. This was due two vari- ables entering into the machining operation which were difficult con- trol. First, the machinist was unable measure the depth the hole ac- curately and several cases the pur- pose was defeated the bottom the hole being drilled too deep into the iron plate. This withdrew the test area from contact with the coat- ing. Second, the method drilling was such possibly force some zine into the test area, resulting false protected regions. effort overcome the above inaccuracy, another set plates was prepared. Grooves various widths were planed across the width the plates, and slight angle with the plate surface, that some point the slot, bare iron was exposed. These plates were exposed atmos- pheric corrosion for 300 days and show some very interesting results. No. as-cast, galvanized malleable iron. heavy red iron oxide slots 1/16in., 3/32 in. and in. wide. Bare iron appears tarnished. The quantity rust wider slots increases with the width exposed No. 21, machined malleable iron galvanized. Same plate No. The plates indicate adjacent zinc has definite influence the corrosion bare iron areas not more than 1/16 in. from the zinc. further substantiate this evidence three more plates which galvanized through with various size holes and then plugged with unprotected iron the same composition. The plugs were pressed into the plates and made level with the zinc coating. Fig. photograph these plates after days exposure. These specimens have since been exposed the weather for total 935 days, and the ap- pearance the plugs has not changed appreciably since the photograph was taken. No. galvanized machine steel plate with bare machine steel plugs. The plug 1/16 in. diameter lightly tarnished, 3/32 in. diameter plug lightly tarnished, in, diam- eter plug shows 0.1 mm. protected rim with tarnished center, 5/32 in. diameter plug shows 0,3 mm. pro- tected rim with rust center, 3/16 in. diameter plug shows from 0.0 1.3 mm, tarnished rim with heavy rust and white salt deposit center, 7/32 in. diameter plug shows 0.6 tar- nished rim with heavy rust center with white salt deposit, in. diam- eter plug shows 0.6 1.2 mm. tar- nished rim with heavy rust center and white salt deposit. No. as-cast, galvanized malleable iron plate with bare mal- leable iron plugs. The plug 1/16 diameter shows tarnish only, 3/32 in. diameter plug shows 0.2 mm. tarnished rim with lightly rusted center, in. diameter plug shows 0.1 mm. lightly tarnished rim with heavy rust center, 5/32 in. diameter plug shows 1.0 mm. lightly rusted rim with heavy rusted center and some white salt deposit, 3/16 in. diam- eter plug shows 0.6 1.2 tar- nished rim with heavy rust center with white salt deposit, 7/32 in. diam- eter plug shows gradually increas- ing quantity rust from rim center with some white salt deposit, in. diameter plug the same the 7/32 in. diameter plug except has more white salts. No. 16, machined malleable iron, galvanized, with bare malleable iron plugs. The plug 1/16 in. diam- eter shows 0.2 mm. tarnished rim with lightly rusted center, 3/32 in. diameter plug shows tarnish all over, in. diameter plug shows 0.1 0.2 lightly tarnished rim with tarnished center deeper color, 5/32 in. diameter plug shows tar- nished rim which gradually increased rusty center, 3/16 in. diameter plug shows 0.5 1.4 mm. tarnished rim with heavy rust center and some white salt deposit, 7/32 in. diameter plug shows 1.0 mm. tarnished rim with heavy rust center and white salt deposit, in. diameter plug shows 0.7 mm. tarnished rim with heavy rust center and white salt deposit. The results these tests lead the conclusion that bare areas iron surrounded hot dip galvanized coat- ings are unlikely rust when such areas not exceed that in. diameter circle. For those who wish make some kind check visual inspection, test available seems more practical than the Preece test. Use and Interpretation The Preece test described the Appendix A.S.T.M. Method, Designation: must Some the important | variables which must controlled the manipulation the Preece test are: preparation the specimens, composition the solution, specific gravity and value the solution, temperature the solution and speci- mens, and agitation the solution during the test. result long study the protection afforded zinc coatings surrounding small bare areas fer- rous base metals, the authors have come the conclusion that very unlikely that rust will appear bare reasonable, then, assume that the appearance bright adherent copper iron the Preece test should not called the end point the test, until such copper deposits reach the area equivalent in. diameter circle. Subcommittee Committee A-5 Corrosion Iron and Steel has submitted tentative Preece test method corporating the control factors recognized essential the proper manipulation the test. believed that such method will soften the criticism the Preece test and render less erratic and more workable. hoped that some test may devised that will satisfactorily measure the weight coating hot dip galvan- ized castings and forgings intricate shapes. Conclusion (1) There are satisfactory methods for measuring the weight and uniformity coating castings and forgings irregular shapes. (2) The weight and uniformity coating such articles cannot controlled the manufacturing proc- ess, but tests show that even the thinnest coats offer ample protection against atmospheric corrosion. (3) Evidence has been shown that corrosion unlikely occur bare areas malleable iron and mild steel surrounded hot dip galvanized coatings when such areas not ex- ceed the equivalent in. circle. (4) recommended that weight coating tests not used until better methods are developed which can used for castings forgings. Visual inspection offers adequate pro- tection for the purchaser. (5) revised tentative Preece test method has been submitted for those who wish check visual inspection. A208-38T The authors gratefully acknowledge the assistance obtained from Messrs. Weidenhamer, chief chemist, the Ohio Brass Co. New Soaking Pits Installed Edgar Thompson Works IXTEEN new soaking pits, built Amsler-Morton burgh, the Edgar Thompson works Steel Corp., Brad- dock, Pa., will add 800,000 gross tons the company’s annual heating capacity, and comprise the largest slab ingot heating installa- tion existence. The pits will used supplying slabs the new Irvin works. in. deep, having ingot capacity ingots 28% in. 38% in., ingots 29% in. 44% in. There are three double span automatic cover carriages for manipulating covers, which new feature pit furnace construction. fourth carriage re- tained spare. All covers are the automatic self-sealing type. THE IRON AGE, January 19, | 4 ~ 1 4 = ‘ ae Recent Design Advances Cutters, ORING tools have been combined with threading chasers large size collapsible die heads for pipe flange work. collapsible boring head with solid T-C bits offered, also drill chuck with length ment. Two new ideas diamond wheel dressers to- gether with self-balancing grinding ORING and tapping are com- bined new turret lathe tool developed the Landis Co., Inc., Waynesboro, Pa. the style LBSR expanding chaser collapsible tap, which was designated for production work flanges chines, boring and tapping head are mounted tandem the tap body provide for taper boring the hole and tapping the thread one pass the tool. pilot bar attached the head and fitting bushing the machine spindle supports the tap and secures proper alinement with the work. The expanding action the style tap obtained through single solid transverse sliding cam, similar the style Landis taps, except that th