The Iron Age 1940-02-15: Vol 45 Iss 7

VAN DEVENTER President and Editor = BAUR | Vice-President and General Manager Managing Editor News Editor Editor Emeritus Machinery Editor Art Editor Metallurgical Bditor Associate Editors Washington Fditors Resident District Editors CAMPBELL ROBERT BINGHAM Pittsburgh Chicago Cleveland Detroit Editorial Correspondents London, England Cincinnati FRAZAR i Boston Hamburg, Germany Milwaukee San Francisco SANDERSON CLYDE ENNIS Toronto, Ontario Birmingham = February 15. 1940 ALLISON Roy EDMONDS Newark, N. J St. Louis TURNER, Buffalo DIX, Manager Reader Service ADVERTISING STAFF B. L. Herman, Chilton Bldg., Phila. H. K. Hottenstein. 1012 Otis Bidg., Chicago H. E. Leonard, 239 W. 39th St., New York Peirce Lewis, 7310 Woodward Ave., Detroit C. H. Ober, 239 W. 39th St., New York w. D. C. Warren, P. O. Box 81, Hartford, Conn Don F. Harner, 1595 Pacific Avenue, Long Beach, Cal Member, Audit Bureau of Circulations Member, Associated Business Papers Indexed in the Industrial Arts Index. Published every Thursday. Subscrip- tion Price: United States and Pos sessions, Mexico, Cuba, $6.00; Can- ada, $8.50; Foreign, $12.00 a year. Single copy, 25 cents. Annual Num- ber $1.00. Cable Address, “‘Ironage, Owned and Published by CHILTON COMPANY (Incorporated) Editorial and Financing Copper Steels Air Conditioning for Aircraft Engines Protecting Steel Against Corrosion Surface Profiles Microinches Casting Steel for Ford Tractors What's New Machine Tools the Assembly Line Washington News THE NEWS BRIEF Weekly Ingot Operating Rates Rate Activity Capital Goods Statistics Metal Working Activity Plant Expansion and Equipment Buying 100 Publication Office Chestnut and 56th Sts.. Philadelphia, Pa., U.S.A 8. BAUR, WILLIAM A. JULIAN CHASE OFFICERS AND DIRECTORS C. A. MUSSELMAN, President i JOS. HILDRETH, Vice-President ust Between Two VAN DEVENTER, Vice-President Executive Offices New York, Y., Products Advertised 119 Vice-President Index Advertisers 148 BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary THOMAS KANE BUZBY, P. M. FAHRENDORF HARRY V. DUFFY Copyright, 1940, by Chilton Company (Inc.) | the | Ne @ ABE | i JOSEPH RYERSON SON, INC., CHICAGO, MILWAUKEE, ST. DETROIT, BUFFALO, PHILADELPHIA, JERSEY IRON AGE, February 1940 ON ty By « 3 THE IRON AGE ... FEBRUARY 15, 1940 ESTABLISHED Vol. 145, No. Futuristic Financing HERE are some occupations, such mining well digging, where success mea- sured one's ability further and further into the hole, but that not true financing. course, certain highly specialized fields, such steel making machine tools, sensitive the extreme business cycle fluctuations, profit not necessarily shown every year. The measure success concerns such fields not one year but the record five, seven ten. Capital goods industries this respect are more mercurial financial performance than consumer industries, which serve broader and more widely distributed demands. One's faith the future company machinery builder that dipped into the red for two three years under adverse business conditions would not necessarily shaken the concern had good management. similar financial per- formance the part service corporation such electric utility might indeed raise the question soundness. Take, for example, the case public service corporation which will call the XYZ company. furnishes broad variety essential consumer services very large and varied body customers. concern which has been business for many years and which, prior the depression and spite recurrent previous depressions, operated black and made profit three years out four since Here the record for that company since Income Outgo Deficit 1933 $2,079,697 $5,142,954 $3,063,257 1934 3,115,554 7,105,050 3,989,496 1935 3,790,046 7,375,825 3,585,779 1936 4,115,957 8,879,798 1937 5,293,840 8,105,159 2,811,319 1938 1939 5,667,824 9,268,338 3,600,514 total deficit seven years $23,263,832 compared with $30,304,579 seven-year income. What you, business man, think this performance? Would you say that the management this corporation was satisfactory, that needed change? Multiply the figures and you have the performance record the United States Government under the New Deal. The record the largest public utility this country which manufactures and sells public service its million customers. : ‘ys } | 2 ka Eng Sure, he’s proud his Dad! And, his Dad and numerous other structural shop execu- tives are proud the bridges and buildings they fabricate with structural sections and plates made Inland. Their preference for Inland results from the helpful co-operation Inland engineers and field men solving tough technical problems—and, the ability the mill put steel where wanted and when wanted from start finish each job. too, can take advantage the economy and satisfaction Inland service calling your nearest Inland office. Sheets Strip Tin Plate Bars Plates Floor Plates Structurals Piling Rails Track Accessories Reinforcing Bars Dad Built this Bridge! hy this country and abroad (see bibliography end report) has shown that 0.40 per cent copper plain carbon reduces atmospheric corrosion, and service records confirm this beyond question. vent the low-alloy high-strength steels, most which are complex al- loys, important know the effect copper conjunction with other elements, and know its in- fluence corrosion resistance was any way related Three copper producers, Phelps Dodge Kennecott Copper Co. and Ana- conda Copper therefore sored Battelle Memorial Institute the effect copper, alone and with other alloying elements, the rust resistance sheet steel. The steels (Table used for the corrosion tests were killed type, and were made ingots from induction furnace melts. spon- results three-year atmospheric corrosion tests steels determine the effect copper the corrosion resistance plain and low-alloy steels. LORIG Vetallurgists, Battelle Memorial Institute were hot rolled sheet 0.040 in. thick and, after cleaning, thickness 0.033 in. Specimens the sheet were tested the as- rolled, the normalized, the normalized and drawn, the normalized cipitation hardened, and the annealed conditions. The heat treatments given the sheet are described notes Table Atmospheric Corrosion Tests Specimens for exposure the at- mosphere were the size and shape shown Fig. which also illustrates the method supporting the sheet for exposure. Before being put expo- sure racks the roof Battelle each specimen was pickled, size and weighed. The test was started October, 1935, and was completed 1938. total five sets specimens each steel analysis and each heat treatment were tested, one set being removed from the racks the end each the following periods: Six months, one one vears, two vears and three years. \fter exposure the specimens were cleaned rust electrolytically bath containing per cent sodium cy- anide, using the specimens cath- odes steel sheets Test runs blank samples showed that iron losses this method cleaning were negligible the time required clean specimen. The cleaned sheets were weighed and the anodes. final weights the specimens de- ducted from the original weights determine the weight from oxidation the air. During exposure none the sheets hecame perforated ragged the edges. all the sheets pit- ted some extent, marked differ- ence the tendency toward pitting THE IRON AGE, February 4 =, & hex 4 : | tink 4 was observed. actual measure- ments the depth the frequency pitting were made, however. The results the three-year cor- rosion study are summarized Table The weight losses are expressed milligrams per square centimeter surface exposed (both surfaces the sheet being subjected exposure) order that weight losses for one steel may readily compared with those another. small influence Since heat treatment had the corrosion losses, the weight losses each steel TABLE the five conditions heat treatment were given averaged Table the table express the weight lost steel three vears percentage the weight lost the same period Average Weight Losses and Corrodibility Ratings for Copper Steels Steel Compositions Per Cent | | | 0.02 0.02 0.15 0.02 Iron) 0.02 0.02 0.15 0.02 0.20 0.02 0.02 0.15 0.G2 0.50 0.02 0.02 0.15 0.02 0.75 0.02 0.02 0.15 0.02 1.25 0.02 0.02 0.15 0.02 2.00 0.10 0.30 0.15 0.02 0.40 0.25 0.30 0.15 0.02 0.40 0.10 0.30 0.15 0.02 1.25 0.02 0.02 0.15 0.02 0.40 0.02 0.02 0.15 0.02 0.40 0.02 0.02 0.15 0.02 0.02 0.02 0.15 0.02 0.40 0.02 0.02 0.15 0.02 0.02 0.02 0.15 0.02 0.30 0.02 0.02 0.10 0.02 0.40 0.02 0.02 0.30 0.02 0.40 0.02 0.02 0.15 0.02 0.40 0.40 0.02 0.02 0.15 0.02 1.25 0.40 0.10 0.30 0.75 0.02 0.50 1.00 0.10 0.30 0.75 0.15 1.10 0.10 0.30 0.75 0.15 1.10 0.50 0.10 0.30 0.75 0.15 1.10 1.00 0.10 0.30 0.75 0.15 1.10 1.50 0.10 0.30 0.75 0.25 0.50 1.00 | 0.09 0.31 0.61 0.14 0.03 0.96 0.09 0.29 0.61 0.14 0.31 0.96 0.07 0.25 0.61 0.14 0.52 0.96 0.08 0.22 0.69 0.14 0.61 0.96 0.09 0.27 0.69 0.14 0.72 0.96 0.08 0.21 0.69 0.14 0.82 0.96 | | 0.09 0.25 0.69 0.14 0.96 0.96 0.69 0.25 0.72 6.14 1.03 0.96 0.08 0.24 0.72 0.14 1.09 0.96 0.09 0.24 0.72 0.14 1.23 0.96 0.10 0.28 0.72 0.14 1.35 0.96 0.11 0.29 0.71 0.14 1.49 0.96 | Compositions first steels are nominal values. Corrodibility Rating 22—THE IRON AGE, February 1940 Other Alloying Elements (added) (added) (added) .20 .20 (added) .20 (added) .20 (added) .10 (added) 0.20 0.20 100 3-Year 2-Year Exposure Exposure Oe 120 100 100 | Sulphur contents all steels under 0.03 Average Weight Loss Steel Average Weight Loss for Base Iron obtain the rating values 114-Year | Average Weight Loss, Mg. Per Sq. 1-Year Exposure per cent. values | | « | | | | < | | | ) | | the base iron—an iron closely approx- imating ingot iron carbon, manga- nese, phosphorus and sulphur contents. Thus steel with corrodibility rat- ing lost only per cent much weight did the base iron dur- ing given period, Atmospheric corrosion data for few the steels the various condi- tions heat treatment are given Table They are typical those obtained practically all the steels and are included merely show that these studies heat treatment had very little, any, effect upon the rate which the steel corroded. Vertical Bakelite Figs. inclusive are plotted curves showing the effect copper the corrosion rate some the steels. Discussion Results Small amounts copper alloyed unalloyed steels increase the re- sistance atmospheric corrosion. The improvement due copper not always the same the low-alloy steels, since the indi- vidual influences two more al- loying elements corrosion are sel- dom additive. evident that mod- erate amounts nickel, tin and alu- minum, for example, add the corro- when used individually, yet when these combined with copper they add little the resistance that obtained from the copper alone. elements are The steels Table fall into three groups with respect their resistance One group consisting the base iron, the 0.10 per cent iron, and the iron which 0.20 per cent was added during melting fall which the corrosion loss three years greater than mg. per sq. cm. This loss considerably above the losses sustained the re- maining steels over the The second group—consisting the simple alloyed steels not included the first group, the binary alloyed steels having copper one constituent, and two ternary alloyed steels containing nickel, molybdenum and copper—is moderately corrosion resistant, show- ing loss three years from 1204 the lower losses being obtained with the steels containing the largest num- ber alloying elements. The data for steels containing 2.00 per cent copper are plotted Fig. show the effect increasing amounts copper atmospheric corrosion low-carbon steel. the copper content increases 0.20 per cent sharp drop weight loss oc- curs. With further increase copper, the effect atmospheric corrosion small indeed. Although Daeves and the American Society for Testing Ma- terials (see bibliography) did not test with high percentages copper those reported here, their results also indicate optimum atmos- pheric corrosion resistance from addi- tions 0.25 0.50 per cent copper. steels Copper and nickel and copper, nickel and molybdenum had the effect corrosion losses shown Fig. retarding atmospheric corrosion, additions nickel-copper were but slightly more beneficial than cop- per alone. The corrosion resistance often expressed terms the life steel for given weight loss. this hasis the life the 0.40 per cent cop- supporting atmos- pheric corrosion speci- mens. IG. 2—Effect cop- per corrosion low carbon steels ex- posed the atmos- phere for three years. mg. per sq. cm. definitely than the third group made the high silicon steels con- taining either copper and phosphorus, phosphorus and chromium, copper and chromium, copper, phosphorus and chromium. this group the corro- sion loss after three years’ exposure ranged from mg. per sq. cm., 0.50 1.00 1.50 2.00 2.50 Copper, per cent per steel for weight loss mg. per sq. cm. twice that the base iron. worth while improvements at- mospheric corrosion resistance cop- per-bearing steels were obtained from alloying them with aluminum, silicon, tin, zine (according chemical analysis only trace zinc was re- THE IRON AGE, February 15, 1940—23 K ' ' ! j | | | | 125 igrams per square mil Veight loss, ‘A Exposure, years IG. 3—Effect nickel, molybdenum and copper the atmospheric cor rosion low carbon steel. tained the steel). shows that benefit was derived from adding 1.0 per cent silicon steels con- taining 0.40 per cent copper. low (0.03 per cent) copper steel con taining 0.09 per cent 0.31 Mn, 0.14 0.61 and 0.96 the curve for the same steel but taining 0.31 per cent copper. weight loss mg. per sq. cm, the lower con- life the 0.31 per cent copper steel was twice that for the steel with per cent According this method comparison, the addition copper. copper appears double the life the alloyed steel just does the the base iron. important change corrosion effected upon raising the copper content the alloy steel from 0.31 1.49 per cent. resistance Both chromium and phosphorus are likewise effective promoting corro sion resistance the copper-bearing, silicon steel the type dealt with The curve Fig. for the copper-silicon steel corroded the same rate the 0.40 per cent iron the weight loss diminished showed shown per sq. after three exposure, value reached the copper-silicon steel one and one-half years. this instance the time required for given weight loss was doubled addi tion per cent chromium. Under not always the case with chromium, for some the steels. particularly those low silicon con tent, the effect chromium 1.00 per cent atmospheric corrosion sistance negligible. from 0.14 per cent the cop per-silicon-chromium unproved the corrosion resistance, most doubling the time required for weight loss mg. per sq. em, The further creased raising the phosphorus con tent 0.25 The corrosion was per cent. rams per square centimeter Exposure, years IG. 4—Effect silicon the atmos- pheric corrosion resistance cop per-bearing steels. raising the phosphorus per less than that obtained raising the phosphorus content from 0.25 cent, however, was per cent. Summary (1) atmospheric sion tests were conducted determine the effect copper the corrosion resistance low-alloy steels. (2) low-carbon low-alloy markedly improved the addition corrosion resistance of Chemical Composition, Per Cent TABLE Atmospheric Corrosion Data from Copper-Bearing Weight Loss Milligrams per Square Centimeter Surface Exposed As-Rolled 0.09 0.14 0.61 0.31 0.96 18.6 Notes Heat Treatments: As-rolled Annealed box annealed 1800 deg. 24—THE IRON AGE, February 1940 heat treatment given sheets the low phosphorus steels were box annealed after rolling. 1650 deg. The steels containing 0.14 per cent Annealed 21.0 22.1 38.8 62.4 more of P were | ny | 0 040% Cu, | 4 040 %Cu & 0.30 { Ay () | Q: | | | | i | 27.8 21.4 21.2 | } rate corrosion the copper-silicon steels. (5) Small amounts tin, alumi num, nickel silicon copper-bear- ing, low-carbon steel had little wm BIBLIOGRAPHY “Copper Steel Influence Corrosion,” Journal wm 0.10%C, Weight loss, Weight loss,milligrams per $52. lustitute, IG. chromium and phos- phorus the atmospheric corrosion resistance copper bearing steel. mospheric corrosion resistance steel containing 0.09 per cent carbon Buek, and Handy, O., “Re 1915, pp. 212-255. 0.14 per cent phosphorus, 0.6! per cent silicon and 0.96 per cent chrom Chem., 1916, pp. 209-216. Richardson, and Richardson, Ind. Chem., 1917, pp. 123 Particularly Regard the Sheeting Material,” Chem. Met. 020 per cent copper. Copper and 21, 1919, pp. 142-144. resistance to atmospheric corrosion the small, (3) Copper was effective increas ing the corrosion resistance silicon 30, 1916, pp. 379-400 Richardson, and Richardson and Chromium and Combinations the Corrosion Corrosion 1916 American Soc. 1929. Daeves, “Die Korrosionbestand- igkeit gekeysterter Thomas Und Sie steels, 0.20 0.50 per cent copper Ingot “Corrosion of Col alt, (4) Chromium phosphorus New York, 1934, pp. 220 241. were likewise effective in reducing the Copper,” Journal Steels Exposed Battelle Memorial Institute Weight Loss Milligrams per Square Centimeter Surface Exposed Normalized and Drawn and Normalized steels containing 0.02 per cent P were heated to cent or more of P were heated to 1800 deg F Normalized and drawn Steels which had been Normalized and precipitation hardened for 3 hr. to effect 1650 deg. F . and then cooled in air. normalized as described above were drawn at Steels which had been normalized described above precipitation hardening and then cooled in air Steels containing 0.14 per 1250 deg for hr. were reheated to 930 dee. F THE IRON AGE, February 15, Si 5 | LAVYUoUI COC, Zz | | interesting tooling set-up for precision work and the adoption new type fluorescent lighting very large scale are two features the new Indianapolis plant the Allison division General Motors Corp., where aircraft engines for the Army will produced larger quantities than heretofore practicable. The main manufacturing plant win- dowless and completely air condi- tioned for control temperature, hu- midity and dust, all which affect workmen and machines. The buildings were designed the Austin Co., Cleveland, and welded construction columns and trusses used through- out. Putting production basis the various models the Allison engine, which require high degree pre- cision workmanship highly finished parts alloy steels and aluminum al- loys, was accomplished adapting ex- isting machine tools, developing new fixtures for existing machines, the development entirely new ma- chines. The milling machines include Hy- dro-tels, hydraulically operated with the latest type controls for main- taining mechanical dimensions both for diameters, irregular shapes and contours and producing finish profilometer measurements. Some the larger vertical drilling machines are specially designed. One machine has hydraulic cylin- der and the work chucked the ver- tical position and rotated around drill in. diameter and in. long. This drill, mounted vertically and stationary the base the ma- chine, will drill depth in. alloy steel forgings used for propeller shafts. CONDITIONING FOR ENGINES battery screw machines vari- ous makes includes Fastermatics for straight boring and straight and contour facing. The internal grinding machines for some the parts are special design and are the result several years experimental development and are the first this type used for produc- tion. equipment there are number larger machines that drill many holes various diameters and depths one operation, The heat treating section located the center the building. Furnaces are all electrically heated and have at- mosphere control. The panel board containing all instruments arranged one end the room, visible from any spot the department. The fur- naces are sunken into the floor, their bottoms extending into The Homocarb and Vapocarb furnaces are arranged that they are conveni- ent the quench tank and panel board. addition anodizing, plating and dichromating equipment there also complete installation for bright cad- mium, nickel, copper and chrome plat- ing. The assembly floor has sub-assem- bly department preceding which located the end the finish store stocks and the whole scheme the layout the plant progressive type. The parts enter one end pass through the machining depart- ment the final inspection and then into the finish stores, through the sub-assembly and are picked off the assembly line along the departments the completed motor. Thence the motor goes the test stands. ° ° ened steel shaft hr., operation previously requiring several hours. Interior view (opposite top) new Allison Indianapolis plant for Army airplane engines. Note the new type fluorescent lighting. The automatic lathe (opposite, center) machines all fins and shoulders the outside cylinder barrel one operation. the heat treating department (opposite, the furnaces and cooling tanks are half sunken through floor facilitate handling work. q é 26—THE IRON AGE, February 15, 1940 For the promotion greater work- man comfort and health and better pre- cision work the forging and casting cleaning equipped with new ar- rangement for drawing off metal dust. The workmen sit long metal tables upon which the machinery placed. slot located along the front edge this table. central blower sucks all small metal particles table surface down into tubes cen- tral exhaust pipe from which the dust harm. Since the slots the tables are di- rectly below the workman’s face and about the level his waist, the suc- tion also draws fresh, clean air down the workman. The factory lighted with newly developed Westinghouse industrial units. Each lighting unit, suspended from the ceiling, equipped with three 40-watt lamp bulbs, 48-in. long and half-inch diameter. Each bulb housed separate Alzac re- flector. The color light produced very close daylight, much that the layman cannot detect any differ- The Westinghouse lighting units are mounted ft. in. above the floor. The average illumination obtained footcandles. The air conditioning housed four penthouses the roof. The equipment divided into eight independent units, each capable pro- viding 52,000 cu. ft. air per min. Because the unique combination factors heat insulation, air condi- tioning and artificial lighting, will take relatively less power create this new approach ideal working conditions than previous attempts. 4 om a ~ work the Corrosion Commit- tees (British), the Protective Coatings Sub-Committee has drawn complete and concise statement the best methods painting iron and steel structures for protection against atmospheric main points are, (1) All the material should thor oughly descaled prior the applica- tion the first priming coat paint. (2) should carried out sand shot blasting some pickling. Exposure weathering, for however long period, followed hand cleaning not recommended, cept special cases. (3) pickling adopted, the du- plex method, including finishing dip dilute phosphoric acid, probably the best. regards descaling, two general principles should borne place late the fabricating process practicable. Due precaution should taken keep the material reason- ably free from rust prior descaling, and the application the priming coat paint should follow immediate- after the descaling process and should take place under good condi- should also allowed. The first point arising remove the rolling scale completely before starting paint. The only al- ternative this painting over the rolling scale. reasons that will discussed later, the latter method can only expected successful the rolling scale intact. -This once presents difficulties. true that certain cases, such sheets which are rolled packs and therefore protected large extent from oxidation, *In the United States, the new method flame descaling considered being extremely successful. See article “Tron and Steel Descaled and Structural Steel Cleaned and Dehydrated Oxy-acety- lene April 20, 1939, issue THE IRON AGE. 28—THE IRON AGE, February 1940 HUDSON might possible dipping the ma- terial paint oil, soon the packs are broken up, ensure that the protective coating applied in- tact and thin rolling scale. eral rule, however, would not practicable keep intact rolling scale iron and steel before painting it. gen- Let assumed, however, that this done, was indeed approximately the case the tests the Corrosion What The tests showed that the rolling scale simply off bodily over large areas and took the paint with has admitted that some the corrosion stations, good results have tained paint applied over the rolling scale mild steel. example, Motherwell, specimens this type are still good condition after eight This equally true, how- ever, specimens that before painting, and expected that the latter will prove have the longer life eventually. exposure. has been suggested, order avoid the possible damage the roll- ing scale and rusting the surface fabrication, that structural steelwork should painted coated with lin- seed oil while still hot after leaving the rolling This procedure has been tried, and again speaking gen- eral terms, not considered ade- quate substitute for descaling, least with present methods The left position under the paint film, and although this one coat thicker, this fact mately lead failure the same type that already This process would limited for large scale application the fact that certain types scale are not suitable for painting. Some are friable and brittle and the paint would flake off very easily with Moreover, the off, condemned. ] presence paint finished section scraped off locally any welding has likely occur the painted handling, fabrication and transit. sum up, the procedure painting metal while hot the rolling mill not regarded generally tory substitute for the methods recom- mended the Protective Coatings Sub-Committee. Weathering Condemned The second point that pickling specified the method exposure rusting until are the reasons for all the trolled. unréliable and one can guarantee remove scale com Thus, the rate descaling steel the atmos phere depends type scale, which turn varies with the temper ature and other conditions rolling. pletely means it. Although the detailed connection tween the rolling temperature and the structure the scale not yet known, certain that some types scales are much more resistant weather ing than others. the case steel, for example, the reddish low-temper- ature scales are more difficult move than the bluer ones formed normal rolling temperatures. least, and Reed showed that they were much less readily removed acid pickling baths. The reason for this that the rolling ferrous metals consists several dif- ferent oxides arranged roughly lay- ers. The larger these, which con- stitutes over per cent the total thickness, consists ferrous oxide. The thinner, whiter includes two strata magnetite and ferric oxide respectively. The relative proportions the three oxides vary according the conditions rolling, and have the properties the scale and its resistance — | | | | | - | | | climatic conditions. obvious, example, that during heat wave summer, Very little descaling will cur The practical consequences the site from large number dit erected different dates and exposed the weather degrees, complete descaling weathering can only realized when the structure long time—by this meant period several This would more harm than good, since many parts the structure would have been excessively corroded Is then and might even require replacing. some means or other, a contractor has exposure the Has then The Because Why the removal the seale has no, only been achieved permitting con siderable rusting fact, the experimental work the Committee has the amount rust remaining steel surface entirely this way equal weight the original rolling brushing. ‘The net result the proc ess has thus been replace the oxides weight the corresponding hydrox ides, which are the constituents rust. true that these hydroxides iron may more firmly attached steel and therefore, less rolling they the rust they might indeed, incorporated the oil the paint applied the sur face and simply act additional pig- ment. Unhappily, this not the case, and the fact that the rust unstable, with the result that blisters form neath any paint film applied over rusted these blisters form? The own view has been established Palmaer and others that rust not only consists various droxides iron, but that, under nor these hydroxides are arranged strata which may chairman the Pro- tective Coatings Sub- Committee the Corrosion Committee (British) herein the findings and the reasons for the findings the committee. These data, first oresented before the Midland Metallurgical Societies, ex- the necessity descal- ing steel prior painting, methods descaling, and types paints use as- sure maximum life steel structures. brushing after weathering expose the lavers rust, which are not equilibrium with the atmos- Although this rust sealed first trom the atmosphere the paint film, moisture and oxygen soon diffuse through the film and react with the rust, giving rise swelling the rust and therefore legiti- mate attribute this blistering the presence the rust, but would were implied that this tvpe blistering invariably immediate failure the paint the paint sufficiently tough and elas tic, failure may not least for some practical purposes, however, this consideration dismissed, because structural steel work ever completely descaled this means. The evil effect the blistering accentuated the pres scale and the swelling the rust, the continuation the rusting process, drives wedge between the metal and the rolling forcing off the scale and the paint with it. This obvious. sum the remarks this tion: may concluded that ing essential and that weathering will not do. The benefit descaling may illustrated some simple tests that have been made wrought iron specimens that have now been exposed for more seven years. Seven the specimens were pickled, the remainder were exposed the weather for six weeks and then cleaned hand various ways. The present position that the paint has not failed the specimens originally exposed and all these specimens were pickled before paint- ing. The net result that the average life two coats paint pickled compared with 2.1 years for wrought iron that had been partially descaled weathering and cleaned hand. Methods Descaling The next question considered how best can descaling carried out. The obvious answer that the most convenient and cheapest method that will give the required result should used. practice, the choice lies pickling and various forms sandblasting.* can only carried out the shop, but sandblast- ing can also practised the field. instance, would not possible pickle the underside railway bridge, but could sandblasted. regards the results obtained, there little choose between the two processes. the tests the Corrosion Committee, slight advan- tage has been observed favor ling ordinary sulphuric acid, but practical importance. is, ever, desirable compare the results obtained different methods de- scaling, even this should only estab- THE IRON AGE, February 1940—29 5 lish that there essential difference between them. series tests has therefore been conducted which the methods pickling include hydro- chloric, phosphoric and sulphuric acid baths and electrolytic pickling. Meth- ods mechanical descaling include sandblasting, shotblasting ing. addition, specimens exposed the weather for various periods and cleaned hand have been exposed. The finishing treatments after pick- ling have also been varied. Some specimens were simply washed hot water, others were immersed lime water solution, while third set was treated with phosphoric acid wash the type which will discussed later. Pending the results these tests, the Protective Coatings Sub- Committee has recommended the adop- tion the duplex process descaling steel pickling introduced Dr. Footner. essentials, this process combines simple chemical surface treatment with the descaling process. generally known that certain surface films metals have protective properties. the case iron, natural oxide film forms when the bare metal has access air. Even this film manifests feeble protective properties under certain conditions and, known, when its properties are modi- fied result alloying the steel with about per cent chromium, will withstand corrosion satisfactor- ily large number media. Films iron phosphate are also re- sistant corrosion, and forms the basis the proprietary phosphating process, which Bonder- izing and Parkerizing are the best known examples. The films formed these processes are, however, complex phosphates containing other metals such manganese. Although they not suffice protect the metal en- tirely themselves, they are ex- cellent basis for paint and enamel and have wide range usefulness. The film formed iron steel when immersed rubbed with simple solution phosphoric acid, al- though much thinner than the films produced the proprietary processes, still has valuable protective properties. The first attempts produce this film structural steel involved descaling the steel phosphoric acid itself. This was costly method removing the rolling scale, although methods re- covering the acid were worked out later.. Moreover, there were technical difficulties associated with the fact that undesirable deposits complex phos- phates were produced after the bath 30—THE IRON AGE, February 1940 had been use for some time. These difficulties have been overcome the process which the metal descaled dilute sulphuric acid bath before, then rinsed water bath and finally transferred for few utes hot per cent solution 185 deg. removing the steel from the dilute phosphoric acid bath, allowed dry its own heat and used red lead and graphite primer for this purpose. The process has the obvious advantage that the use large quantities expensive phosphoric acid avoided. Consequently the cost low and, according Footner, rather less than 34d. (about per sq. ft. plate. Moreover, has the great merit being foolproof, since traces noxious acid are left the plate. Panel Wash Used view what has already been said concerning the damaging effect rust beneath paint film, ciple that steel work should painted immediately after descaling should accepted everyone. This not al- ways practicable, however, and such cases the so-called panel wash may service. are several com- mercial brands panel wash the market. Their main field usefulness for application steel that has be- come slightly rusty after descaling. For instance, the London, Midland Scottish Railway Co., uses wash its own, which applied the steel panels used for car construc- tion. panels are, however, pickled specification the works origin and the panel wash merely removes the effects any slight rust- ing which occurred during the process fabrication. should made clear that ex- isting panel wash capable over- coming the deleterious effect gross rusting non-intact rolling scale beneath paint applied steel sur- face. This view was held few years ago some our friends Amer- ica, who, after they had been remon- strated with gently correspondence and told that our view descaling was the correct procedure, they even- tually wrote say that practical ex- perience had proved that our view was correct. They are now advocating sandblasting combined, agreed very properly, with the use panel wash the descaled metal. is, course, very desirable devise panel wash that would capable dealing with heavily rusted stock, and research this end being conducted least one quarter. Having prepared the surface, the next thing choose the paint, and the first point that the primer should inhibitive paint. What meant this? Broadly paint that tends prevent steel from rusting result chemical action its sur- face. This distinction neutral excluding paints which merely pro- tect the metal hindering the ingress moisture and oxygen. not fully known how inhibitive paints work, but for practical purposes the lack this knowledge not essential. can imagined that the presence the pig- ment the paint strengthens the natu- ral oxide film the This clearly reasonable assumption the case chromate pigments pig- ments with alkaline reaction. What- ever the explanation may be, there doubt that inhibitive primers give superior results. Choosing Paint The choice finishing paints not, the whole, important that the priming coat, and paints good quality are roughly equivalent. This may seen, for instance from the following facts namely, the average life paint systems using finishing coats red oxide iron paint was 3.8 years, that micaceous iron ore and aluminum was 3.7 years, and the case two the other paints the life exceeded 3.2 years. will, how- ever, noted that red oxide iron heads the list and, although this has not invariably been the case, may taken that well formulated red oxide iron good quality forms very satisfactory finishing paint and that difficult improve upon it. the same time, there doubt that there room for material improvement the properties paints themselves, and probable that these will achieved the introduction syn- thetic resinoids and other modifications the paint vehicle. perfectly logical question for the practical man ask would the fol- lowing—we know that established that when exposed at- corrosion the bare condi- tion, certain low-alloy steels containing copper copper and chromium are appreciably more resistant corro- sion than ordinary steel. this su- periority manifested the protected condition? other words, the user has keep structures painted, worth while pay the additional cost constructing them low-alloy difficult give precise an- swer this, but the basis the experimental data obtained, the answer | > % 4 i i : | ! | | | proper protection steel, descaling essen- tial and weathering will not do. descale, the British recommend pickling and various forms sand blasting, whereas this country the new technique flame descaling be- coming increasingly popu- would follows—if the structure such that there doubt that maintenance, that is, repainting will perfectly efficient, then from the point view corrosion resistance, there would advantage using low- alloy steel. If, however, there danger that maintenance will incomplete, say, from rea- sons inaccessability the desire get the maximum possible life from the protective coating and thus reduce maintenance costs, then the use of low-alloy steels should prove eco- that paint behaves better low-alloy steels than ordinary steels. ment has shown that the average life paint ordinary steel was 2.8 years, while copper-chromium steel has exceeded years. Metallic Coatings Before commencing discussion metallic coatings, the writer wishes state frankly that does not know very much about them. That if, proposed do, statements are confined strictly facts that have been personally observed. the work the Protective Coatings Sub-Commit- tee can continued without interrup- tion and subject the ordinary human sible three four years time deal with the subject more fully than one yet has conducted complete sur- vey protective metallic coatings for iron and steel, although the American Society for Testing Materials has hand very large series field tests coatings suitable for wires and fencing products. remedy the de- ficiency, the British Sub-Committee has arranged for systematic tests coatings applied in. steel flats which will exposed similar manner the standard specimens the Corrosion Committee. coatings seven different metals and alloys—zine, aluminum, lead, tin, cad- mium, lead-tin alloy and zinc-cadmium alloy, which will applied many different processes possible and different thicknesses. The specimens will exposed atmospheric and marine corrosion, the former case six different stations. this way will obtained for the first time merits the different metals and the various processes application. the commencement the war the preparation these specimens was al- most complete and was expected have them all exposed the end this year. The work has been delayed little, but now being pushed ahead, and the hope commence exposure comparatively shortly. the average, zinc times less corrodible than iron the open atmosphere, although heavily cor- rosive industrial atmospheres the ratio falls one-seventh one-eighth. humid, enclosed and polluted atmos- pheres, however, zinc corrodible iron itself and protective coatings are therefore useless. This probably because the zine corrosion products are deliquescent and keep the specimen moist. galvanized coatings will give reasonable protec- tion steel for times the order five years, even the most heavily polluted atmospheres. general, mistake economize the coating thickness, although course this can adjusted suit the type ex- posure and clearly need not great the case sheet farm- barn the heart the country S.W.G. steel wire would increased from years when coated with 0.001 in. (0.6 oz. per sq. ft.) and the case wire ex- posed industrial atmosphere, zine coating 0.003 in. (1.80 oz. per sq. ft.) would increase the life from years. Finally, remains add that the use sprayed coatings for pro- tection against marine corrosion in- creasing. probable that the use sprayed coatings and pos- sibly other metals for marine work will greatly extended the near future. THE IRON AGE, February 15, = eo ‘ ¥ ig | | f 3 od / | itp must have been sooner later, the question “How much microinch has been asked again the experts mechanical surface finishing. has been asked again because the microinch which has been used most recent discus- sions only mathematical concept— though frequently that fact appears have been overlooked. asked again, too, author- avers—the means which have been used determine microinch values roughness metal surfaces had led many the conclusion that mere re- duction degree roughness was the road perfect load bearing, wear resisting surfaces. Now the announcement tvpe surface measuring instrument and its installation the Chrysler Su- perfinish Laboratory Detroit prom- ises alter considerably some already established ideas. Heretofore, the measuring method most widely used gives meter readings representing continuous running aver- ages the heights and depths sur- face irregularities millionths inch microinches. Mathematically, the microinch referred this case the root mean square the plus and minus values the curve representing the surface Obviously, this r.m.s. type reading not determi- nation the maximum irregularity the surface. Its nearest scientific parallel the r.m.s. value voltage given a.c. voltmeter. Departing from the measurements surface finish should Development present defects, the IRON AGE, February 1940 Brush surface analyzer provides topographic charts the surfaces finished parts. Readings less than micro- inch, absolute, can made. Analyzer head and drive mechanism are shown the left, connected direct-inking oscil- lograph and chart flexible drive shaft. the center the calibrating amplifier. With rigid standard mounted sur- face plate, the analyzer head can adjusted vertically and horizontally, moved around for positioning above test 3311 Perkins Avenue, Cleveland, has designed direct recording instrument for rapidly analyzing the topography finished surfaces. The instrument noteworthy first all because ously, analysis was means the cathode ray oscillograph type in- with recording means motor-driven laboratory set-up. the other hand, only the generalizer type has been successful until now shop instrument for anything resembling production spection because gives neous reading. Second noteworthy fact that the surface analyzer gives micro- inch readings which are absolute val- ues rather than values aver- ages. Magnification 100,000 times permits the making satisfac- tory records surface irregularities smaller than one-millionth inch. Plotting every detail pography, the instrument furnishes instantaneous and irregularities, showing not only the amplitude, but also the form these irregularities. The nature the curve which thus plotted automatically such that indicates how closely the surface approaches perfection. This, according Wallace, Chrysler Superfinish developer, will direct the attention experimenters the job rather than one which only has de- creased “roughness factor.” The Brush instrument consists specimen. surface analyzer head mounted adjustable stand, calibrating ampli- fier and direct-inking oscillograph, indicated the photograph. Sepa- rately the various elements have been used the past scientific apparatus that their reliability and accuracy called Bimorph crystals, used both the analyzing head and actuate the pen which records the profile moving chart, have been used nograph electric pickups and also the cardiograph. The amplifier also taken directly from the latter The analyzing head pickup jecting from gear drive mechanism. Mounted behind hardened steel po- sitioning shoe, guide, used explore the specimen surface sapphire tipped, with radius in. The shoe rides over rela- tively wide area the surface and provides reference level. The mo- tion this stylus over the test sur- face irregularities transmitted through mechanical linkage the piezo-electric crystal varying pressure which generates voltage hetween the electrodes the crystal element. This voltage directly pro- portional the stylus deflection and the order 0.0015 volts per croinch deflection. The amplifier magnifies this voltage much times. The crystal mounting electrical J | ~ circuits are such that sensitivity vir- tually independent temperature va- riations ordinarily encountered. The protective tubing for the mounted the extreme end the pickup arm, which pivoted spring conical bearings attached the gear drive mechanism. The output the crystal element connected calibrating amplifier means single conductor shielded cable. The drive head gearing and cams impart the the pickup either rotary motion describ- ing circle 0.050 in. diameter, reciprocating motion describing straight line 0.050 in. long. One com- plete either motion takes sec. Either motion may knob top the drive case. Power required for operating the gear connected the chart motor the direct-inking oscillograph. The calibrating amplifier cially designed two-stage type sup plied with necessary power equipment which operates from 60- cycle supply. The plies all the necessary gain (magnifi cation) between the analyzing head and the direct-inking oscillograph. calibrated step-type attenuator cluded the input the amplifier provide various degrees magnifica- tion pen movement 100,000 times, including mechanical amplifi- cation. cluded which supplies “test” voltage for adjusting the gain the amplifier provide any desired deflection the oscillograph chart, accurately cor- related the sensitivity the pickup arm. Each pickup arm brated and the sensitivity constant supplied with the unit. the most sensitive setting the amplifier, the deflection the chart the oscillo- graph may high mm. (ap- proximately in.) per inch deflection. The output the amplifier con- nected record the irregularities the surface under test, picked the analyzing head and magnified the calibrating amplifier. The oscil- oscillo- cable. lograph equipped with direct-ink- ing pen actuated crystal element which controlled for stabilization, and the fluctuations the pen are recorded moving paper chart. The crystal-driven pen designed for stiffness and low mass which enables respond rapid tions per sec. This accomplished while delivering sufficient power the pen overcome frictional errors. maximum deflection mm. (ap- proximately in.) each side the zero axis obtainable. The chart feed mechanism driven synchronous motor which also drives the pickup travel mechanism. This insures constant speed through gear train, providing selection any one three rates feed fol- lows: 1/5 per sec., equivalent approxi- mately times linear magnification. in. per sec., equivalent approximately 100 times linear magnification. in. per sec., equivalent approximately 500 times linear magnification. For most purposes, appears that feed in. per sec. provides the most easily interpreted chart. charts illustrative the topography finely finished surfaces. Left, Section chart Superfinished round shaft. Vertical magnification mm. microin. Horizontal scale magnification, Chart speed in. per sec. The maximum surface irregularity seen microin. The corresponding profilometer reading microin., r.m.s. Right, Brush surface analyzer chart finish ground surface. Vertical scale, mm. equals microin. BRUSH ELECTRO THE IRON AGE, February 1940—33 . \ i} \ \ \V \\ | \ \\ | \ \ 4 ge ‘ a4 CASTING STEEL FOR FORD TRACTORS development new Ford tractor and several accompany- ing implements, containing unusually high proportion castings, has focused attention foundry technique. The total weight the tractor 2100 which more than per cent castings. In- cluded are 553 gray iron, 173 Ib. malleable iron, lb. miscellane- ous non-ferrous castings, and 381 Ib. steel castings. The task designing the tractor was started with the idea mind making the best possible use new analyses metal, and new processes developed recent years for the pro- duction steel castings. the beginning the metallurgist and foun- drymen cooperated with the design en- gineers. order into volume produc- tion cast steel tractor parts, and put some new ideas into practice, the steel foundry was revised and The result was that steel castings could poured continuously instead inter- mittently ordinary practice. This was achieved utilizing electric hold- ing furnaces and conveyor reels which bring the molds directly pouring spouts. The system not only saves time but produces more uniform cast- ings, because the metal for each cast- ing delivered uniform tempera- ture and uniform composition. Fully automatic casting not feasi- ble except the case some parts uniform weight such crankshafts. Semi-automatic casting the practice for miscellaneous parts—front axles,