The Iron Age 1940-07-04: Vol 146 Iss 1

1940 JULY — > ~ — | | | ines give clean cutting and extreme These shearing ¥ ve 4 all WRIGHT Man oging E Jitor OLIVER JULY 1940 VOL. 146 NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager J. A.ROWAN T. W. LIPPERT News Editor Technical Editor Associate Editors PHAIR A. |. FINDLEY Editor Emeritus F. J. WINTERS Art Editor Washington Editors L. W. MOFFETT JAMES G. ELLIS Resident District Editors CAMPBELL ROBERT BINGHAM Pittsburgh Chicag Cleveland Detroit Editorial Correspondents Buffalo Cincinnat FRAZAR CHARLES POST Boston San Francisco HUGH SHARP CLYDE ENNIS Milwaukee SANDERSON ROY EDMONDS Toronto, Ontario St. Louis LEROY ALLISON Newark, Editorial What Price Technical Articles Chip Curler for Carbide Tools..................... Report Electroplaters’ Convention American Society for Testing Materials What's New Materials Handling Feature Reports News and Market Reports News Industry Personals and Obituaries Metal Working Activity Comparison Prices Summary the Week District Market 100 Machine Tool Activity. 106 Fatigue Cracks Free Industrial Products Advertised Index Advertisers. > z Advertising Staff Union Bidg., Cleveland B. L. Herman,. Chilton Bldg., Philadelphia Hottenstein, 1012 Otis Bldg., Chicago Leonard, 100 Eost 42nd New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 East 42nd St., New York Warren, Box 81, Hartford, Conn Don F. Harner, 1595 Pacific Avenue, Long Beach, Cal. Member, Audit Bureau Circulations Member, Associated Business Papers Indexed the Industrial Arts Index. Pub lished every Thursday. Subscription Price: United States and Possessions, Mexico, Cuba, $6.00: Canada, $8.50; Foreign, $12.00 year. Single copy, cents. Annual Number Non-Ferrous Metal 107 Scrap Market and 108 Fabricated 110 Reinforcing Iron and Steel 112 Ferroalloys, Pig Iron Prices.. 117 Warehouse Prices Sales Possibilities Owned and Published CHILTON COMPANY (Incorporated) Publication Editorial and Office Executive Offices Chestnut and 100 East 42nd St. Philadelphia, Pa. New York, U.S.A. U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, GEORGE GRIFFITHS, EVERIT B. TERHUNE, VAN DEVENTER, BAUR, WILLIAM BARBER, Treasurer BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY Vice-President Vice-President Vice-President Vice-President Vice-President CHARLES HEALE 4 wok 172 - 2 - For Real Vacation... TRY THE “Vacation without Worry” PLAN RYERSON CERTIFIED STEEL PRODUCTS INCLUDE Structurals, Plates, Sheets, Tubing, Shafting, Strip Steel, Alloy Steels, Tool Steels, Stainless, Babbitt, Weld- ing Rod, ete. Write for Stock List. 22—THE IRON AGE, July 1940 You can have real vacation this year and every year you follow Ryerson’s “Vacation Without Worry” plan. need wonder about interrupted shop schedules! need worry about uncertain delayed steel deliveries! Just leave memo saying: “Call Ryerson when steel all! you have complete assurance that all emergency and regular orders will handled with equal care. immediate shipment. close your desk! Pack your bags! Have fun, and relax! Ryerson the job. Joseph Ryerson Son, Inc., Chicago, Milwaukee, St. Louis, Buffalo, Cincinnati, Cleveland, Detroit, Boston, Philadelphia, 4 4 What Price Liberty? the ironics our times that are now building the greatest war machine earth the hope that shall never have use it. are preparing spend billions for guns and tanks that hope will rust and fall apart without seeing active service; billions for bombing planes that trust will never bombard enemy; billions for training millions young Americans for war the hope that they will never fire gun human target pierce fellow man with bayonet. ask ourselves why are doing this. Doing willingly, yes, eagerly, spite knowledge that the cost doing will add severely the national debt and tax burden and thus the future burdens every living citizen. Why are doing this? Doing not merely with the consent but upon the demand the overwhelming majority our people, with scarcely dissenting voice? are doing because have suddenly been awakened threat the American Way life and also appreciation it. Not long ago, there were quite number people our country, some even high places, who did not appreciate the American Way. Many them tried tell that the Russian way the European way was superior and that should junk the old-fashioned form constitu- tional government that was handed our founders, and build modern economy based regimentation and centralized planning. In- deed, was quite fashionable preach against the American Way, and when unruly and vociferous youngsters did so, they were petted and fed from august tables. JULY 1940 Some them said that the Supreme Court was out date; that there was nothing like hinder progress those modern countries ESTABLISHED where one man said (and you usually died). 1855 Well, times have changed. People our country are seeing and thinking more clearly today, because they have been suddenly awakened realities after being lulled sleep rhetoric. family may sleep night taking its home and belongings commonplace and for granted. But when explosion takes place next door, all members the family hasten salvage their possessions. with the American Way. The American Way that stands for individual liberty. The new schools totalitarianism have persuaded their people trade their liberty for so-called social security. France today has social security sort since bowed Hitler. have the German and French and Belgian and Dutch and Polish and Norwegian dead. There have been those this country who would have trade liberty for fictitious social security. Indeed, there have been those brazen their effrontery make even the lowliest laborer believe that sums extracted from his meager pay were being put aside provide him security his old age. When, fact, every penny thus collected has gone down the rat hole deficit expenditure. Insurance for Liberty. How are going get it? choosing our leader during the coming crucial years man whose intellectual honesty unquestioned and whose ability get things done has been demonstrated. “ae I + | j a } | Nie j | i and Structural Service Includes Cost-reducing Engineering Cooperation like the Inland 5-point plan cooperation structural work, because will save you time and money. offers you— Engineering assistance which often enables designer make important savings the use steel. Suggestions Inland engineers and field men who fre- quently can point the way time and labor-saving shop methods. Practical cooperation planning for simplification field work. Deliveries that put Inland Steel where you want it, when you want it, from start finish each job. Floor Plate has the struc- Rigid devotion the Inland standard quality. tural strength rolled steel. you have problem structural design, fabrication, con- assures 4-way safety combined struction, invite you talk over with Inland engineers. This cost-reducing engineering cooperation yours without obligation. platforms, runways Call write your nearest Inland office. with long wear all floors, SHEETS STRIP TIN PLATE BARS PLATES FLOOR PLATES STRUCTURALS PILING TRACK ACCESSORIES REINFORCING BARS J | 4: / q Dearborn Street, Chicago Sales Offices: Milwaukee, Detroit, Kansas MANUFACTURER who finally bilities production economies carbide tools may likened the boy who, after watching the skillful demonstration the salesman, decided all looked easy handle. But when tried use the Yo-Yo everything went hay-wire. When appealed friends who had acquired the knowl- edge skillfully handling the toy— how they did it—the usual remark was, “you just got find out for your- self. Throw just hard enough SUIT, The manufacturer finds carbide tools plunked right tools with the happy optimism new convert. And why not? heard how Blank Co. had such wonderful success with their carbide they show reductions manufacturing costs high per cent some jobs? Blank Co. can it, then Mr. Manufacturer can it. But something went Sure! The tools were sharpened nice smooth edge but started cutting steel why, them chips just piled around the machines like hay-cocks. That would never do! The chips might get caught the revolv- ing machine and fly all directions and hurt somebody! Chip Curlers for Carbide Tools GAYLORD THOMPSON Madison, see what Blank Co. about that. “We grind chip curlers depth and width SUIT,” their reply. Then referring the carbide manu- catalog recommendations Mr. Manufacturer finds that here too, the instructions are grind SUIT. Naturally the facturer going exclaim, “what heck SUIT. What are the dimensions? have draw- ing SUIT?” Well, this article just humble offering for the solution these ques- tions—an offering founded tried and proved facts grinding chip tion data accumulated after months tests and comparative analysis and which have kept broken tool losses down less than per cent. There may some slight variation where material construction the part machined would require exceptional change angles dimensions. These conditions are few, however, and not alter the fact that standardiza- tion data that will cover more than the average requirements for chip curler specifications efficient and desirable one. the sharpening carbide for the old time mechanic Wis. divorce the ideas has sharpening high speed steel tools. Old cutting tools were ground with plenty rake—chips would shear and slide down the rake smooth- ly, but owing the comparatively cut-feet the chip problem was not acute. Fundamental laws me- chanics applied the grinding high speed steel cutting tools seemed violated the grinding car- bide tools. too, the layman mechanic inclined term “the quickly water when gets too hot handle while grinding. And why special wheel for grinding carbides? extremely advisable have all grind- ing done specialist. might appropriate mention here that in- experienced mechanics, men who were acquiring training machine tool operators have proved good operators with carbide tools because their very ignorance old accepted standards and capacities cutting steel did not stand the way their following instructions implicitly. They had not become saturated with the methods machining with high speed steels that such knowledge would clash with the apparently unorthodox methods with tools. Chip curlers play important part the life and cutting efficiency car- THE IRON AGE, July og wed 7, | | mig ( ° ° ° ths (he a 2 | : carbide tools. FIG. and 2-A—This type chip curler not fully satisfactory, but headed the right direction. and 3-A—This type chip curler has given better results than any other type evolved. "Rake" FIG. FIG. 4-A FIG. 4-B IGS. 4-A and 4-B top rake carbide tool that has certain advantages and productive good results. bide tools. The curlers may ground too wide have effect the tool and chip—or they may too nar- row that the chip just the gap” and continues long steely ribbon (see Fig. 4)—or too deep, with the consequent destruction the cut- ting edge. Rather than into wordy about chip curlers, would advisable consider some illustrated examples. herein are very much enlarged, per- necessity slightly exaggerated order give understandable picture tool and chip action when under work- ing strain. Even with this slight ex- aggeration the illustrations, the true fundamental actions the tool and the chip not changed. Figs. 1-A, and 1-B, illustrate type chip curler that detrimental carbide tools. These illustrations are the front view turning tool. Note the right-angle wall that backs 26—THE IRON AGE, July 1940 the chip curler Now note 1-A which shows how the chip slides off the work and down the rake the chip curler until strikes this wall. When the chip strikes this wall, pressure exerted against the tool which has tendency push the tool away from the work noted the arrows. there any play the cross-slide tool-post, the tool point will pushed away from the work far the play will permit. Having reached this maximum, there increase pressure exerted until the chip finally buckles and breaks the middle, shown Fig. 1-B. The tool thus released from the back thrust and immediately plunges back into the work denoted the ar- rows, but often, not until the down- ward pressure the tool point which caused the bending the chip and the outward pressure, has broken the tip off the carbide blade. All this happens during series rapid vibrations when the tool action. the tool point not broken off, the chips pop off the tool and fly all directions the tool feeds into the work rapid jerky mo- tions. The life this tool very low work. tool this type was given work-out forgings Hyten steel in. diameter in. wide. The chips flew from the tool with singing sounds characteristic the sudden snapping spring steel. The chips would land the floor their natural color and would then immedi- ately turn deep blue hot steel. The rapidity with which the chips passed from the tool point and snapped the floor was faster the discoloring action the heat stored but disclosed the error grinding carbide tools this manner. The cut- feet however was abnormal, being 596 ft. per min. cut in. deep with 0.016 in. feed performed Gisholt No. heavy duty turret lathe. The tool broke down due excessive vi- brations caused the square wall the back the chip curler. Fig. shows another type chip curler that fundamentally headed the right direction. However, shown 2-A, any acute angle top rake will not take the pressure exerted “A” deflect the chip and consequently will break off the tip the approximate location shown Fig. illustrates the shape the type chip curler that has given com- plete satisfaction over any other type vet evolved. Fig. 3-A shows the ac- tion the tool while work. Note that the chip peeled off the work deflected the hump the back the tool point shown “A.” (The hump created grinding small “land” shown Fig. 6.) This hump removes all strain from the cutting edge the tool leaves this cutting edge perform the main duty siz- ing smoothing out the roughness caused tearing away the chip from the work. The hump “A” has pretty much the same effect peeling off the steel from the work the fin- ger the human hand peeling orange. Now regards the cutting edge “B” this same illustration (Fig. 3-A), note that there small air space just above the edge the tool. This air space caused the hump the tool deflecting the chip “A.” This air space ideal that the cut- ting edge does not come contact } FIG. FIG. FIG. 3-A with the material such extent cause immediate dulling de- struction the edge. the was made wider the metal would bear down the cutting edge the tool and consequently shorten its life dulling breakage. Then too, the class finish the work would suf- fer. the land was removed entire- ly, there would other result expect than the immediate break-down the cutting edge shown this point well give con- fact that hot carbide tool dipped cold water being subjected com- pouring water into cold glass reverse- exampled. clearance underneath carbide tip and became too hot handle. The shank was dipped cold water leaving the carbide end exposed the air. The tool slipped from the grasp the worker and fell into the pail water and when retrieved—the carbide was ruined multitude minute frac- tures caused unequaled contractions the materials that constituted the carbide tip and steel shank. lesson can taken from this what could expected where cool- ant used inefficiently steel cutting operations. When Facer Facer 14° Front 5—This facing has radius with chip curler ground straight with the cutting edge. Enlarged Side View Turner w part the carbide tools buried un- der the steel while cutting, naturally has high temperature. the chip should happen break away and ex- pose for moment the extremely hot cutting edge the carbide tool the coolant, reasonable expect neg- ative consequences. Likewise, the tool has been cutting for some time and the end the cut the tool point suddenly showered the coolant, the same result can expected. This condition somewhat alleviated where cutting oil used. The cooling effect not quite shocking the tool. Several workers who were having trouble keeping edges from breaking off carbide tools used Gisholt No. high production lathes, were in- structed remove the coolant from the work—to run the work dry. The supposition was, that the inability keep the tools flooded because the nature the work was destructive the tool when the coolant finally came contact with the tool did spas- modically. The results dry cutting were gratifying. The habit omitting coolant carbide tools became prev- alent among the workers because the apparently better results obtained. bar turning machines, however, the old reliable cutting oil still neces- sary where roller turner tools are use. Top rake carbide tool has its Fic. curler dimensions for carbide tools which have proved satisfactory. THE IRON AGE, July 1940—27 ° ° feature and productive re- sults. But when the top rake steel cutting grade carbide provided the milled and brazed condition, there inconvenience caused this rake when chip curler ground. shows this type tool, front view. Note that the carbide brazed place angle for top rake. groove merely ground place for chip curler, the cutting edge higher than the back the tool and causes the chip “jump the (see 4-A). Now then, the cutting edge “A” ground down the level the rear edge the chip curler shown Fig. 4-B, can readily seen that rapid depreciation the carbide will experienced be- cause excessive grinding. The top rake milled and brazed tool excellent and economical tool used cast iron, but the tool used for cutting steel braze the carbide blank flat the shank and take care the rake with the chip curler, shown Fig. 3-A. idea that seems prevalent that carbide turning tools should kept away from jobs that require radius the tool for cutting fillets. doubt much the trouble encoun- tered with rounded points carbide tools due improper grinding. Especially where chip curlers are in- volved. Fig. shows facing tool having radius with chip curler ground straight with the cutting edge. there was not radius the tool, this style chip curler would satisfactory. Note that the width the curler does not extend back the radius. Note the top view. The front view shows how this fault aggravates the cutting efficiency the When the chip curler ground, naturally brings the cutting edge toward the center the tool, shown “A” front view, because the clearance angle. This leaves the rear portion the radius still the original width and deprived cuting edge, shown both views. The result that the point will drag across the face the finished work and roughs the tool were dull. other words, the edge cutting and the point which left the grinding the chip curler, drags over the work with woeful results. The chip curler round nose carbide tool rake near possible from every point the radius. Excellent results have been realized from round nose tools ground this manner. Fig. shows chart compiled from average chip-curler dimensions and physical characteristics mate- rials. This chart not universal “cure-all” for chip but the boiled down substance two extremes form working aver- age. provides, realized ex- perience, the seemingly correct funda- mentals from which curler elaborations can evolved. other words, this chart has proved correct actual operation that changes suit special jobs excep- tionally difficult steel are very neg- ligible. The largest radius covered this chart in. The larger the radius, the greater the chip curler angle. The chip curler angle is, course, affected the width the carbide also. The view Fig. shows the end view the chip curler and the width the “land” and the angle the rake. The letter denotes the grinding away the extended portion the tool that would likely rub the surface the work after the tool point over it. The three tools “A,” and are facing tools. The three tools and are turning tools. The amount stock that can removed tools ground shown the chart should not exceed one-third the width the carbide where radii are involved. conclusion, the causes broken carbide tools are not always due im- proper grinding. The machine stop- ping while cut process, pieces that are being machined coming loose the chuck jaws, dragging the tool back across the work backing away from the work, bumping the tool against the work, all contribute tool mortality. every case, broken tool should gated and the cause causes rem- edied. gratifying note the good results that accrue from taking these precautions. And should not forgotten that many costly form tools will automatically discarded because the high production capac- ities properly supervised carbide tools. Exposure Tests Electroplated and 1932, atmospheric exposure tests plated coatings steel were initiated joint committee the American Electroplaters’ Society, American Society for Testing Ma- terials, and National Bureau Stand- ards. 1936, similar tests were started with plated coatings various non-ferrous metals, and 1938 these were supplemented with tional coatings. the 1936 and 1938 exposures, some new plated steel speci- mens were also included order confirm and extend the earlier obser- vations steel. recent paper the National Bureau Standards, summarizes the results these tests since 1936. While some 28—THE IRON AGE, July 1940 the specimens may longer periods, especially the mild- locations, believed that subse- quent observations upon them will not materially alter the conclusions based upon the exposures the present time. (1) The most important factor the protective value nickel-chromi- the thickhess the nickel coatings. (2) steel zinc, layer copper under the nickel adds little the protective value thin coatings. With thick deposits, the value the composite coating ap- proaches, but does not exceed, that nickel coating the same total thick- ness. (3) Variations the methods preparation and nickel which included the use four bright nickel solutions supplied 1938, had large effects upon the protective value the coatings. (4) Variations the thickness the chromium coating from 0.00001 0.00003 in. applied over nickel have very little effect, but 0.00005 in. more, cracking likely occur, especially over nickel coatings brass. (5) Variations between basis metals given group have large effects. quired furnish given degree protection than brass, and greater steel than 4 | | | | | / ° ADOLPH BREGMAN Consulting Engineer, New York ° ticles dealing with Right Metal the Right designed aid man- ufacturers selecting the most suitable non-ferrous metal alloy for their prod ucts. portance industry only few respects almost all its uses call for the form thin coat- ings alloys. However, some its attributes have important bearing the qualifications the mixtures which plays important part. Tin one the very high purity metals. The highest purity commercial tin runs 99.9 although tin 99.987 purity available commercially physical properties tin are given great detail the Metals Hand- Mantell, which includes an_ extensive bibliography. Another valuable reference Hedges and Homer, for the International Tin Research and Develop ment Council. “Protective Coatings for by Burns and Schuh, 1939. premium and tin with purity high 99.9999 has been reported. Tin white metal with specific gravity about 7.3 and melting point 232 deg. (450 deg. F.). strength low, about 2000 Ib. per sq. in., and its elastic limit, about 200 per sq. hardness about very ductile and plastic, but hardened and embrittled addi- tions small percentages other metals, such antimony, copper, iron, bismuth, silver, impervious light rays, moisture constituents. extremely property its low surface tension the molten state, its ability wet other metals, which accounts considerable measure for its success its major use today, tin-coated steel. those metals wet each other which form solid solutions com- pounds with each other, compounds with iron: and FeSn. The tin-iron layer com- pound tin plate approximately 0.00002 in. thick, coke tin plate the coating ranges from about 0.00006 in. Ib. per base box) about 0.00015 in. (2.5 per base box). \nnealing the tin plate increases the percentage alloyed tin and the size the crystals. food distribution, hous- ing, printing, industry and the arts, tin has become one the most important commercial metals One the most valuable advantages softness, its low melting point and its miscibility with many other metals make available for casting, rolling, extrusion (cold), spinning, stamping, drawing, forming, etc. can cast without difficulty metal molds steel bronze, for example, type the linotype machine, and mil- lion varieties novelties and jewelry; either under pressure hand-pour- ing permanent mold castings. Perhaps the most interesting illus- tration its ease workability the well known process forming col- lapsible tubes. disk tin placed die and struck sharp blow cylindrical tool. Most the metal squirted the force this blow through the annular space between the cylindrical tool and the die and the wall the tool, thus automatically producing tube. part the tin remaining the die the same time formed into the shoulder and nozzle the tube. Chemical Properties The outstanding chemical property tin its ability resist attack air and many organic chemicals, in- cluding those food products. resistant whole range acid THE IRON AGE, July 1940—29 ? SE ~ | ¢ ! 4 : i ay | yest media. many cases may at- tacked these acids with the dis- placement hydrogen, but the ab- sence oxygen the attack ceases due the high hydrogen over-potential— retaining film hydrogen atoms its surface which retards further at- tack. oxygen present, however, removes the hydrogen combin- ing with form water and the at- tack proceeds. Moreover, many cases (even where some attack occurs presence small amounts oxygen) the products the reaction between tin and foods are innocuous the hu- man system the small quantities which they may exist. Tin rapidly attacked strong alkalies and ordinary inorganic acids under exposure air. Applications discussing the uses tin, necessary consider its various manu- factured forms, shown the ac- companying table, furnished Inter- national Tin Research and Develop- ment Council. employed today, tin appears (1) solid metal tin”); (2) coatings (tin plate); (3) alloys; (4) chemical compounds. ing, its supreme function for con- tact with food, drink, confectionery and other products for human con- sumption. Its use solid metal naturally restricted its cost, but widely installed the form pipes made extrusion, breweries, bot- tling works and chemical plants. Be- cause its ability retain moisture and keep out light, another consider- able use solid form, though very thin, foil and collapsible tubes for wrapping and containing food, confectionery, pharmaceuticals, metics, adhesives, paint products, to- bacco, electrical condensers, cables, gun charges, etc. also used powdered form for poses. THE USES TIN food, pharmaceutical, cosmetic, toilet, adhesive collapsible tubes paint products Extrusion _ beer, water, chemicals and carbonated drinks decoration foil wrapping of:—cheese, chocolates, tobacco; electrical condensers, cables, gun charges METAL Powder co wire Hot- dipping TIN on other metals alloys ——————— termeplate Spraying Chemical precipitation alloys anodic treatment tunning Electro- deposition foo —— cans powders, cigarettes, tobacco, creams, ointments, — other pills, films, tennis balls, oil, grease, petrol, coffee, sia teas containers tea, cocoa, salt, pepper, biscuits, confectionery, COATINGS cakes, paints, lacquers, glue, polishes on iron late ware caps. and closures, crown corks, toys, gasmeters, advertising signs, kitchen utensils, spools dairy and brewery equipment, kitchen utensils, hot-water apparatus etc. on buttons, pins etc bronzing decoration hardware vegetables, fruits, fish, meat, soups, milk, cream, —$|= butter, margarine, beer, fruit juices, jams etc tinned brass, tin-washed lead pipes roofing, drums, kegs, petrol tanks, packing case linings equipment for food industries, decoration etc. Sold cans, radiators, electrical, sanitary and er sheet metal jointing, general plumbing purposes White-metal bearing alloys ———————— railway rolling stock, engines bearings, shafting etc gears, pumps, chemical plant, springs, pipe unions, Bronze ————- valves, wire screens for paper making, statuary, bells, ornamental fittings, coins etc. type metals domestic and church, decorative metal ware dental fillings capsules, packing rings, die-casting alloys, Other alloys fusible alloys —_——.[* extinguishers and alarms, boiler safety plugs, 4 castings and moulds, solders and seals etc. ALLOYS Type Pewter dental amalgams miscellaneous tun oleate Organic CHEMICAL COMPOUNDS Inorganic tin chloride pattern alloys etc. lubricating and textile oils pharmaceutical uses oxide enamel opacifiers textile dyeing, bleaching agent, weighting natural silk 30—THE IRON AGE, July 1940 important variation the ap- combination with other, cheaper met- als, such fashion make use its protective properties minimum expense. So, for example, have containers which the main body lead with thin layer tin the outside inside, the case may be, for contact with the other materials Other ex- amples are tin-lined copper and brass tubes for protection against attack certain waters and distilled water steam condensing systems. also used the dairy industry coating for copper vessels; pas teurization; refrigeration; for car- bonated water; sheet roofing, etc. unusual example re- cently noted butter mixer with cast iron body and coating tin from 0.003 in. thickness, using the nate solution. Another interesting place for tin coating for copper conductor wires the electrical industry, pre- venting reaction between the copper and sulphur the rubber insulation, and consequent deterioration. primary use, coating for steel sheets, rests upon four essential properties: (1) its ability resist the attack the food products and other materials contained; (2) the ease applying the tin coating; (3) the easy closing sealing the container soldering; (4) its resistance atmos- pheric corrosion and retention pleasing luster. One the most important elements the success the con- tainer preserving foodstuffs that when they are introduced into the can, most the oxygen content dis- placed steam, and that when the can sealed and cooled, partial vacuum results. noted above, after brief attack the tin the acids the products contained the can, the hydrogen film the surface re- duces the subsequent attack neg- ligible amount. For that reason, free- dom from pores the tin coating the inside the can much less important than the outside. Another important use for tin plate based its attractive appearance sheets allow the full use color print- ing, lithographing, for decoration, ad- vertisement and design unlimited variety. Although the overwhelming propor- tion tin plate carries very light coatitig, some grades are ‘ _ ——_S$ ~ = | | q | q special service with deposits 0.001 in. resist severe corrosive con- ditions for long use. example, the gas meter, which made largely tin plate, functions without de- terioration for years. Another special type coating what known terne plate, where tin-lead alloy coated steel sheets. tin varies from per cent per cent the coating which extremely heavy, and the terne plate used for roof- ing and similar severe work, such cans for lubricating oil, stamped arti- cles, ete. Important improvements have been made more recent years methods applying tin coatings. The metal may sprayed molten tin with spray gun onto the metal wire. This method has the vantage availability for coating large and complicated pieces situ, decorative treatments non-metallic well metallic surfaces. Still another method obtaining tion (the “contact” process) solu tions cream tartar and salt, for articles, like pins, buttons, are coated with tin this fashion, not only for protection but for its pleas- ing appearance. Necessarily, such coat- ings are very than even the thinnest hot-dipped proaching commercial use the ap- plication tin strip electrode- position. Both acid and alkaline baths are being tested different mills and, although details are not publicly avail- able yet, there general agreement that electro-tinning due become distant date. Tin Scrap material high cost tin discarded, even after has lost its Parts made block tin tin are easily salvaged remelting and alloying. Tin foil similarly recov- erable although requires more care than heavy metal prevent excessive oxidation, drossing, ete. plate, however, obviously much more problem. Out the hun- dreds methods covered patents only few are commercial opera tion. The most important are (1) electrolysis, solution sodium hydrate and oxidizing agent and (2) treatment with dry plate few the thousands novelty forms daily use. Photo courtesy Apollo Metal Works. products are pure tin, with the suitable for remelting. The dry chlor- ine method produces tin tetrachloride for the silk industry and other uses. Summary Tin, fully much any other metal and perhaps many ways more so, has been outstanding contributor the advance civilization. has TABLE Consumption Tin the United States 1937, Finished Products (Tin Content) Gross Tons Primary Secondary Total Tin plate 39,221 39,221 Solder 12,026 7,832 19,858 Babbitt Bronze Collapsible tubes 3,571 Tinning 2,585 Foil 1,456 1,460 Chemicals (other Tin Oxide 793 1,204 Type metal 1,140 1,361 Galvanizing 997 997 Bar tin 652 174 826 Miscellaneous alloys 506 White metal 374 407 Miscellaneous 506 603 Total 72,928 17,202 90,130 *From Minerals Year Book, 1959. quantity included under cellaneous.” made possible the production cheap- and more universally distributed food making food storage safe and economical tin coated containers. housing, tin indispensable form solders for plumbing and sanitary installations. tin-base alloy producible automatic casting machines, has been one the lead- ing forces making printing cheap enough available the masses and facilitating the reduction illiteracy during the last century. industry the tin base bearing Babbitt metal moved power transmis- sion long jump forward. Tin base alloy solders have made metal prod- ucts manufacture possible millions items. bronze bearings for ma- chine parts, bronze for chemical screens for paper making, has formed vital cog the industrial wheel. the arts, tin bronze for statu- ary and church bells, pewter for domestic and other forms decora- tive metal ware, has done its full share. seems rest upon the future gen- eral industry. this time important new uses outstanding new forms tin, are not apparent. There are occasional excursions into new fields, like, for example, the recent use tin electroplate automobile pistons. However, the main, its progress will rather along the lines expansion present uses for food, housing, printing, industry and the arts. THE IRON AGE, July i Sey 2 t WATERFALL Cassel Cyanide Co., Ltd., Birmingham, England ° ° ° bath case hardening methods used the United Kingdom are different from those the United States, and success with such methods has been very pronounced abroad. These methods are critically examined the author herein. Last week, attention was directed depth and hardness, brittleness related case hardness, cyaniding temperature, etc. conclusion, descriptions are given core properties steel treated cyanide, case hardening malleable iron, distortion, cyanide bath economics, etc. ORE TREATED CYANIDE: Some- times found that mild steel parts lightly cased cyanide relatively low temperature fracture easily and show brightly crystalline core. has been said that nitrogen from the cyanide bath penetrates dur- ing treatment into the core the piece and produces brittleness the same way embrittlement pickling most unlikely explanation. The reason for the brittleness almost certainly related the steel structure before treatment. From very many analyses, has been shown that carbon further into the steel during cyanide carburizing than does nitrogen intro- duced the same time (see Tables and II, last week) indicating that the nitrogen picked during treatment the cyanide, remains the small parts are made from annealed normalized mild steel having coarse structure ferrite grains sur- 32—THE IRON AGE, July rounded pearlite envelopes, then the ment during cyaniding, say 780 800 deg. (1436 1472 deg. this temperature the pearlite (0.9 per cent C.) the forms austenite and quenching the original coarse grain retained. The ferrite small sections now surrounded martensite per cent C.), which account brittleness and position around the treated, since fracture martensitic areas. The original coarse grained piece was not markedly brit- tle because ductility, particularly the surface layers ferrite, coupled with moderate ductility When surface ferrite are replaced case and pearlite the core replaced hard martensite, distinct brittleness tained. Table gives results steel coarsened 900 deg. cooled sand, then reheated quenched from the temperatures indi- cated. Table shows that coarse grained pieces reheated 770 deg. (1418 deg. F.) and water quenched are very temperature 800 830 deg. pro duces improved impact figures. The martensitic areas are now softer and more widely distributed due creased solution ferrite original austenite the temperature increases. the frac tured pieces indicated, however, that pieces quenched from 800 830 deg. was mainly due plastic deforma- tion the metal the root the notch, and when once crack formed rupture the metal this vicinity continued easily across the remain- der the section. This suggested that case had been applied the speci- mens, little improvement impact would obtained elevation the quenching temperature from 770 deg. (1472 1526 deg. F.). The results shown Table VII were pieces carburized the pack cooled and reheated the tempera- tures shown. can seen that when pieces are coarsened during carburiz ing and then given single reheat with water quench, improved impact fig- ures are not obtained until the core has been refined and that intermediate | | | | | f ~ = | | | | i | ' | | | | | ° ° 7 q temperatures 800 850 deg. (1472 1562 deg. F.) not produce improved impact resistance. These re- sults, although produced hardened pieces, can quite well ap- plied cyaniding. Steel with coarse grain and pearlite envelopes around the grain should not cyanided 760 850 deg. (1400 1562 deg. when good core properties are re- quired. Such parts should cyanide hardened 900 deg. when refine- ment the core will effected. should, however, remarked here that steel with carbon content above the upper limit 1015 steel should not quenched from the higher temperatures into water when good ductility required the core. example will best illustrate the point. Steel pieces 7/16 in. diameter, analyzing 0.23 per cent C., 0.60 per cent Mn, nickel nil, Chromium <0.01 per cent, were rather coarse grained. When treated for min. cyanide 780 800 deg. C., quenched, brittle fracture resulted for the reason mentioned for min. 850 deg. 880 deg. (1562 deg. 1616 deg. quenching, brittleness was tained due too high core hardness, although fine fractures were obtained, particularly the 880 deg. speci- men. When quenched from the same temperature (850 880 deg. C.) the core hard nesses were satisfactorily low and duc- tility satisfactory. therefore ad- visable when cyanide hardening this higher carbon material 850 (1662 1616 deg. F.) quench oil for natively, pieces could oil quenched from 850 900 deg. C., reheated 780 deg. C., and water quenched, when the core hardness much lower than direct water quench from 850 900 deg. Core hardnesses when water oil quenching from the vari- ous temperatures are shown Table and graphically Fig. specimens deg. Several years ago British Govern- ment metallurgical department exam- ined the response various alloy steels case hardening cyanide and the box. The three types steel used 2315, 2515 and Krupp. Results are set out Table IX. Pieces each steel were carburized the same depth cyanide and the box, all being refined and hardened the con- ventional manner, details which are shown. Some the Izod test pieces had been machined finish size observe the effect the hard cases 500 400 IG. 9—Varia- tion core quenching tem- perature, for Vickers kilo load) water and 200 quenching. 100 800 1427 1472 produced the two methods. can seen from the table that test pieces given steel show similar proper- ties when treated either method. Moreover impact specimens which case was applied gave equivalent re- sults for and box carburizing indicating that the case produced the former method not more brittle than box carburizing. The low case hardness Krupp steel most likely due retained austenite. Case Hardening Malleable Considerable quantities heart malleable iron are being 825 850 875 1562 900 1652 deg. Quenching temperature case hardened per cent cyanide baths. Due the method manufacture, the casting has after an- nealing relatively thick ferritic band the outside and this has poor wear resistance. The surface greatly improved treatment for min. 900 950 deg. the cyanide bath give 0.015 0.02 in. case, followed air cooling and reheat 800 deg. C., with oil quench. Surface hardnesses thin sections reach 700 V.P.N. faces thicker sections rather less. but generally above 400 V.P.N. The whiteheart iron must fairly well Time, hours Fig. curves for alkaline earth chloride bath. THE IRON AGE, July 1940—33 ° ° ° | | | | quenched 10 sa’ = | 0 | TABLE Variation Impact (S.A.E. 1015 Steel) After Water Quenching Prior Reheated Quenched Impact, Maximum Stress, Treatment Ft.-Lb. Tons Per Sq. In. 900 deg. 800 deg. Water and cooled 830 deg. Water sand. 900 deg. Water 37.5 TABLE VII Variation Impact Strength for Pack Carburized Specimens (S.A.E. 1015 Izod Pieces Machined Size Before 760 deg. 780 deg. Carburizing (In Pack) 0.025 in. 900 deg. and slowly cooled This piece received further reheat 770 deg. Reheated 800 deg. 850 deg. 900 deg. Quenched Impact, Ft.-Lb. Water Water Water 1.5 Water Water and water TABLE Core Hardness for Steel (0.23 0.60 Mn) After Water and Oil Quenching Vickers Hardnesses Fracture Heated for min. Core (30-Kilo Load) Water Per Cent NaCN Water Quenched Temperature Shown Quenched Quenched Specimens 780 deg. 234, 235 162, 165 Brittle Remarks 800 deg. 258, 265 168, 169 Brittle 850 deg. 402, 420 205 Brittle 880 deg. 415, 422 210, 218 Brittle 880 deg. 205 215 Tough This specimen oil annealed, otherwise hardness and brittleness met, but some resolution temper carbon usual. Blackheart malleable cannot treated the manner just described because the excessive carbon re- solution, resulting core brittleness. very thin hard skin can, however, produced immersing for hour per cent NaCN) 600 650 deg. C., followed water quenching. Distortion After Case Hardening Parts water quenched after applica- tion shallow case 830 900 deg. are sometimes found have expanded, generally making bores and holes oversize. Occasionally parts have been scrapped for this reason. Similar parts free from case expand slightly not all when quenched from the same temperatures. has been found experiment that components with shallow cases are more prone the expansion trouble. the case depth increased the tendency for expan- sion becomes less, until with depth 34—THE IRON AGE, July 1940 heated 780 deg. and water quenched. case governed the component question shrinkage instead expan- sion occurs water quenching from 850 900 deg. sometimes found too costly carburize sufficient depth allow quenching water from say 900 deg. C., without bore expansion. then advisable increase the depth case 100 per cent, oil quench from the carburiz- ing bath and reheat 780 deg. C., and water quench. Less expansion will obtained with 780 deg. water quench than with 900 deg. water quench. The high rate heating baths sometimes tends cause cer- tain amount distortion slender parts. Such should heated 350 400 deg. before immersion the carburizing bath, the latter maintained relatively low tempera- ture 800 deg. and quenched oil, provided high case hardness not essential. Better hard- nesses can obtained carburizing 900 deg. C., the temperature being allowed fall 800 deg. before quenching oil. cyanide Relatively high strength baths, approximately per cent NaCN, run relatively high temper- atures, are course more expensive maintain than lower strength baths operating lower temperatures. The use carbonaceous covering does however help matters greatly; indeed, would not possible work the high temperature (950 deg. C.) high strength bath economically without the covering. The more effective the cov- ering reducing access air the surface the salt, the lower the cyanide consumption. The develop- ment coverings having greater ciency will aid from the eco- nomic aspect, since the greatest fall bath strength comes from atmos- pheric oxidation and not from break- down cyanide contact with clean steel immersed the bath. Some air is, however, necessary for carburiza- tion steel cyanide take place, hermetically. per cent NaCN bath operating 950 deg. requires additions per cent NaCN per hour maintain the strength when working under carbonaceous covering. There are two ways reducing this consumption apart from the question efficacy carbon covering, (a) reduce the bath temperature, (b) reduce the maximum bath strength. Both can done when parts have only receive, say, 0.005 in. case that large quantities work are heated 900 deg. per cent NaCN, given 5-min. soak and quenched water. The case will got partly during heating and partly soaking 900 deg. only necessary use the high temperature 950 deg. when depths case 0.015 in. more are desired, but loss output experi- enced when case 0.005 in. ap- plied temperatures much below 900 deg. per cent NaCN bath is, course, more economical run than one analyzing per cent NaCN. only hard skin steel desired, satisfactory. Frequently, how- ever, small firms use single bath for surface hardening and application deeper cases, and then with the lower strength baths the depth hardness suf- fers, can seen from Fig. (shown last the strength baths the salt going generally greater than the dragout, necessitating removal some the melt before regeneration, the bath level maintained constant. | | | | H | | | | e ' | | | } } } d | > and per cent NaCN baths are regenerated with NaCN, and per cent baths are re- generated with per cent NaCN, per cent NaCN salts. Sometimes baths lower cyanide content than per cent NaCN are use for skin hardening 1015, heat treating replenished with the per cent salt since this usually contains chlorides, which help fluidity baths low cyanide content. The use per cent NaCN for this purpose results higher carbonate content than with per cent NaCN for any given anide percentage. per cent NaCN salt sometimes finds use for reheating car- burized work. Simply making drag- out normal working (at say 780 850 deg. C.) under covering will usually maintain per cent NaCN the melt, and fluidity satisfactory. Alkaline Earth Baths There are only two main types carburizing salt baths use Britain. Little known production working with such baths those regenerated with The cyanide bath has decidedly better fluidity than the alkaline earth marked advantage some instances, particularly where only one salt bath furnace installed and where variety treatments, such casing depths in., light casing alloy steels, hardening tool steels being car- ried Moreover cyanide decidedly more soluble water than alkaline earth chloride salts, which important factor when washing parts after oil quenching from the salt bath, particu larly salt trapped small holes. the other hand baths high alkaline earth chloride, e.g., composi- tion (B) below, confer given case shorter time than the high cyanide baths (50 per cent NaCN). More- over, with the former the proportion glass hard zone the case will increased. The high alkaline earth chloride bath also more economical use. described below. Two types bath are used: (A) alkaline earth chlorides per cent, sodium cyanide per cent; and (B) alkaline earth chloride per cent approximately, Cyanide per cent. The balance the TABLE Response Alloy Steels Cyanide and Box Hardening S.A.E. 2315 S.A.E. 2515 KRUPP Cyanide, Cyanide, Cyanide, Type Steel Per Cent NaCN Box Per Cent NaCN Box Per Cent NaCN Box Cased Approximate Approximate Approximate Treatments Core Specimens Per Cent Proof Stress, 770 Deg. and W.Q. 760 Deg. and Tons Per In. 25.5 25.2 26.8 27.0 42.7 46.9 Ultimate Stress, Tons Per In. 54.8 55.0 47.2 48.2 87.0 89.5 Reduction Impact, Cased Depth Case, In. 0.023 0.023 0.022 0.031 0.022 0.022 Impact, Vickers Hardness 798 822 742 752 536 505 TABLE Copper Plating Necessary for Stopping Off Case Depth Time Bath Copper Thick- Required, In. (B) 950 Deg. ness Required, In. 0.02 min. 0.00025 0.03 hr. 0.005 0.04 hr. 0.001 0.05 hr. 0.0015 0.06 hr. 0.002 0.06 0.12 0.0025 two baths consists alkali chlorides and carbonates. These baths are covered with car- strength, reduce heat losses from the bath surface and prevent fume. Cy- anide is, course, essential for car- burization take place. the case straight cyanide baths, there evidence that the carbonaceous covering enters into the carburizing Bath (A) when correctly regen- erated gives results tween strength (30 per cent NaCN) cyanide baths and baths composition (B), and approximately equivalent high strength cyanide baths when operating conditions. composition (B) shown Fig. 10. The glass hard part the case (on after refining and total depth. This type bath tend- ing replace pack carburization 0.08 in. various branches engi- neering, including automobile, machine tool and the heavy industries. The case depth which can applied not, however, limited 0.08 in. In- deed, case depths 0.160 in. are being frequently applied such baths Diesel engine camshafts. The case produced approximately eutec- toid composition. For uniform working, regeneration the bath carried out daily adding alkaline earth