The Iron Age 1938-12-01: Vol 142 Iss 22

FRITZ FRANK President VAN DEVENTER Editor Wanaging Editor News Editor Editor Emeritus R. E. F.J. WINTERS’ T. W. LIPPERT Machinery Editor Art Bditor Metallurgical Bdibor Associate Editors PHAIR JURASCHEK Consulting Editor Washington Editor Resident District Editors T. C. CAMPBELL ROBERT G. BINGHAM Pittsburgh Chicago Cleveland Detroit Editorial Correspondents London, England Cincinnati G. FRAZAR P. FipRMuc Boston Hamburg, Germany MEYER Milwaukee SANDERSON CHARLES San Francisco ASA JR. Toronto, Ontario Birmingham ALLISON Roy EDMONDS Newark, N J. St. Lowis TURNER, JR. Buffalo Owned and Published CHILTON COMPANY (Incorporated) Editorial and Offices West 39th St., New York, Publication Office Chestnut and 56th Sts., Philadelphia, Pa. OFFICERS AND DIRECTORS Cc. A. MUSSELMAN, President FRITZ FRANK, Executive Vice-President FREDERIC STEVENS, Vice-President JOSEPH HILDRETH, Vice-President GEORGE GRIFFITHS, Vice-President EVERIT B, TERHUNE, Vice-President WILLIAM A. BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JOHN VAN DEVENTER, JULIAN CHASE, THOMAS KANE, CHARLES BAUR, BAUR, General Advertising Manager DIX, Manager Reader Service Member, Audit Bureau of Circulations ; Member Associated Business Papers Indexed the Industrial Arts Index. 1 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. Cable Address, ‘‘Ironage, N. Y."’ ADVERTISING STAFF Emerson Findley, 621 Union Bldg., Cleveland Sts., Philadelphia, Pa. H. K. Hottenstein, 802 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. B. Robinson, 428 Park Bidg., Pittsburgh D. C. Warren, P. 0. Box 81, Hartford, Conn. Contents DECEMBER 1938 Old and New Meet Totalitarianism Hairline Imperfections Lowering Charging Costs Cleveland Foundry Case History Finishing Zinc Alloy Die Casting Characteristics Industrial Drive Design Innovations Material Handling Operation Washington Weekly Ingot Operating Rate Rate Activity Capital Goods Plant Expansion and Equipment Buying Just Between Two Products Advertised Index Advertisers Copyright 1938 Chilton Company (Inc.) Lloyd’s London refused issue insurance when the $2,000,000 Jonker diamond was successfully cut Lazare Kaplan and his son, Leo. But, dramatic this diamond- cutting operation was, far more stake the metal forming and cutting operations modern industry. here that Allegheny Ludlum serves— serves with years’ experience that has resulted fine steel service which reduces unit costs and increases output. you have any design operating problem that involves fine steels, A-L engineers and metallurgists are your service. Inquiry places you under obligation. Write Allegheny Ludlum Steel Corporation, Oliver Building, Pittsburgh, Pa. STEEL CORPORATION 30—THE IRON AGE, December !938 380% INCREASE New England manufacturer spools and bobbins was dissatisfied with the performance his cutting knives. felt that their cutting edge dulled too rapidly, and that regrinding was too frequent. Consulting Allegheny Ludlum, was advised use L-XX High Speed Steel, temper. did, and cuts per grind jumped from 2,500 12,000— increase 380%. LUDLUM PITTSBURGH, PA. and Jomorrow- q ES q ESTABLISHED 1855 THE IRON AGE ... DECEMBER 1938 Vol. 142, No. Old and New Meet HERE quite vociferous group young intellectual radicals country, some them high places, who believe that our Con- stitutional Government old fashioned. They want become up-to-date, like Russia, Germany and Italy and adopt the totalitarian principle. These three countries have new model governments which have been designed and built since the World War. They are efficient governments, designed for speed and quick movement. People these modern coun- tries lose time debating questions public policy, old fashioned Democracy. There each these countries one ruler and one voice. That voice says: ''Do and you you die. There also another country with new fashioned Government that much the news today. Japan. Its form Government also totalitarian, even though old fashioned military despotism. Strangely enough, the intellectuals Washington and elsewhere who would have throw away our slow and cumbersome Democracy favor redesign based the modern nations such Russia, Germany and never mention copying Japan. Yet all intents and purposes, far the people are concerned, these modern governments are identical with Japan and with the dictatorships which existed the absolute mon- archies the world before revolution established democracies and re- publics. Stalin, Mussolini and Hitler were all socialists begin with. And socialism originated, abroad, protest against the lack personal liberty absolute monarchies. not strange that these disciples socialism, once power, have gone the absolute monarchs the past and present one better the way one-man rule? HAIRLINE MPERFECTIONS The Nature Hairlines And Methods for Their Detection Semi-Finished And Finished Steel Products URING the last decade, the question surface finish has become paramount impor- tance. This fact may attributed pri- marily the advent the magnetic type non-destructive test, which exemplified the magnaflux test, and the tremendous strides that have been made the aircraft and auto- motive industries. These two factors have made the steel industry con- scious, more than ever before, the fact that minute imperfections hairline appearance proportion have always been present steel and steel products and are the basic cause for the present—it may line period” the art high quality steel making. These hairline imperfections, which have been encountered both the steel producer and the consumer, are extremely important this cause not known what actual ef- fect these minute discontinuities have upon the service performance highly stressed parts. this uncer- tainty, and the knowledge that cer- tain amount these imperfections have expected even though intelligent interpretation their rela- tive seriousness not available, which prompted the author attempt cover the subject matter both from the angle defining the term “hairline imperfections” and briefly describe 32—THE IRON AGE, December 1938 the prevailing methods employed the detection these defects semi- finished and finished steel products. the same time, effort has been made develop the relative merits the standard test methods which are now employed the various steel manu- facturers and During the course this work, the author corresponded with many the leading metallurgists America and Europe means questionnaire, intended ascertain their views, opinions and experiences this prob- lem. wished this time ac- knowledge and thank these gentlemen for their cooperation, and re- gretted that space limitation prevents TABLE Frequency and Severity Rating per Hairlines Un- Test der Over quency ity 107 205 CARL SHAPIRO Consulting Engineer, Syracuse, the presemation their gratifying replies. supplementing the results the questionnaire with experimental work, possible classify and define all minute imperfections steel follows: (1) hairline imperfection may gen- erally defined discontinuity, crack metal. gated non-metallic discontinuity due the presence non-metallics sions, etc. (III) Streaks, ghost lines, dendrites, are considered solid heterogenei- ties metallic non-metallic nature, both, within the material, due the segregation element elements, solid solution(s) compound(s) other than non-metallic inclusions seams. not unusual that many in- stances regular surface sub-surface cracks seams, ghost lines, etc., the causes which not need further discussion this time, are often im- properly termed especially the imperfections are rather minute. viewéd from the stand- point, actual hairline defects (Figs. are best described minor in- ternal discontinuities varying sever- ity representing typical condition the melt. While the severity this hairline condition may vary from in- ‘ q | got ingot and even from the bottom the top individual ingots, must nevertheless considered charac- teristic condition heat metal, which may either minimized ac- centuated suitable improper sub- sequent processing practices. However, the problem is, primarily, and always will be, matter melting procedure. During the course this investiga- tion, attempts were made differen- tiate between those hairlines which are actually formed the melting, pour- ing during the solidification the steel; that is, during the liquid state, and those defects such as_ strain cracks, ruptures, flakes, etc., which are known introduced the material while the solid state during the hot cold working, heat treating machining the steel. deter- mine these factors and, possible, the cause hairline defects, series 6-ton basis electric furnace heats (Heroult type) low carbon nickel, chrome-nickel, and chrome-vanadium steel were processed under carefully controlled furnace practices, including the selection scrap materials, ad- justed melt-down and refining periods, temperature control, time alloy ad- ditions, time and type de-oxidizers, etc. These heats were completely inves- tigated both regard their charac- teristics and quality the plant well their acceptability and product. The test methods employed the mill determining the prop- erties these melts include hairline test inspection top, middle and bot- tom sections the second, middle and last ingot cast, macro etch tests the top, middle and bottoms all in- gots, the determination the non- metallic cleanliness the material, the McQuaid-Ehn grain size rating, and microscopical examination for plant, the finished products made from these heats were primarily inspected the magnaflux test. brief description the various test methods which were employed are given the following paragraphs: (a) Taper Test Hairline Inspection Method: Hot rolled specimens in. round in. long were smooth machined, finish ground and polished in. length taper from in. diameter (discard 1/16 in. side) one inch. The specimens were etched for two minutes concentrated hydro- chloric acid 180 deg. F., washed, dried alchol and inspected means nification diameters. The length and total number the observed im- perfections were then considered and the results expressed terms frequency and severity rating, which based upon the (1) Frequency num- ber hairline imperfections men, (II) Severity imper- fection value per specimen obtained weighing each hairline severity factor varying according its length follows: Under in. length, severity chined into step-down test pieces making three steps approximately in. length and in. variation diameter. After fine finish grinding the surface these steps, the samples were lightly etched con- centrated hydrochloric acid 180 deg. F., washed, dried and inspected under magnification diameters. While the merits the taper versus the step-down test method will later the subject discussion, may stated this time that com- ABOVE tion fine (at the right) hair- ward from the steel surface. Both views 100 diameters. RIGHT Longitu- dinal sections 100 diameters. factor X1; over in., severity factor X2; over in., severity factor X3; and over in. length, sever- ity factor X4. illustrate this procedure, assume that nine specimens show the imperfec- tions listed Table The data shown Table would classify the hairline condition the heat having average frequency rating 11.9 with severity rating 22.8. Subsequent this taper test inspection, the specimens were ma- mercial basis the taper test method should given preference the step- down test method except where the ultimate finished size the part for which the material used definitely known. (b) Macro Etch Test: Cross-sec- tions annealed in. square billets well the finished bar stock are given the standard 1:1 hydrochloric acid etch. After wash- ing and drying, the etched disks are THE IRON AGE, December 1938—33 | < | 7 magnification diameters for any general localized acid attack. (c) Non-Metallic Inspection: Hardened full mens are prepared for non-metallic inspection dry polishing, which consists rough grinding through No. 320 emery paper 40, No. 120, No. 180, No. 320) and finishing No. and No. 000 French emery paper, followed 20-sec. polish wet wheel covered with levigated alumina. After polishing, mens are examined microscopically magnification 100 diameters. (d) Test: This well known test for the determination the austenite grain size rating steel carried out accordance with the recommended A.S.T.M. practices, with the added precautions giving all the specimens the same amount mechanical hot work reduction and prior heat treating which consists normalizing and annealing opera- tion. (e) Test for the Determination Ferrite Banding: Representative speciments in. are heated 1650 deg. for four hours and slow cooled 600 deg. the rate deg. per hr. After polishing longitudinal direction and etching lightly per cent nital, the micro- structure examined 100 diameters and compared with set standards. (f) Magnaflux Test: While this test method described detail later this article suffices state present that the specimens were inspected both the wet and dry methods. The results obtained showed that these tests are not very practical for the steel maker apply routine inspection test method bar stock, etc., which afterwards pro- cessed fabricator, since the final product which subjected the magnaflux test influenced many factors which the steel producer can- not anticipate nor control. The results obtained from the fore- going investigation seem indicate very definitely that true hairline im- perfections are directly traceable the melting practice and are controlled the gas (oxygen, carbon monoxide, carbon dioxide, hydrogen, nitrogen) and non-metallic compound content the melt, and depend upon the methods which are employed during the melt- down and refining, the deoxidation, time alloy additions, temperature control the heat well the speed pouring and subsequent solidifica- tion the ingot (ingot size and shape, thickness mold wall, etc.). 34—THE IRON AGE, December 1938 not wished this time discuss further the influence the aforemen- tioned individual operations, but well remember the control hairline imperfections steel, the well known axiom “melting hot and pouring cool.” The effect various other ele- ments, such carbon, silicon, chrom- ium, molybdenum, nickel, etc., upon the hairline characteristics certain melts, was also investigated. How- ever, date this work has not pro- gressed sufficiently warrant further discussion. Nevertheless, may stated that due their chemical com- position, certain grades steel, especially low and chrome-nickel types such 2512, 3312, well highly alloyed steels are more susceptible poor hairline condition than steels less complicated analytical makeup and, the before mentioned steels, more difficult control the degree free- dom segregation, including banding, non-metallics, porosity, hair- line characteristics, etc. Test Methods for Minute Imperfections The importance using com- mercial test method sensitivity for the detection these hairline imperfections obvious and does not require further explanation. The various test methods which usu- ally are employed for routine inspec- tion may classified under the head- ings: (a) Destructive tests; and (b) non-destructive tests. natural that the non-destruc- tive method primarily adapted the inspection finished articles; whereas, the former greatest im- LEFT IG. 3.—Cross-section seam (above) and longitudinal section 100 diameters. RIGHT 4.—Bars 0.889 in. (upper) and 1.5 in. steel from which 1/10 the diameter has been re- moved each step. The upper bar shows numer- ous fine hairlines; the lower bar reveals large hairline. The bars were etched min. boil- ing per cent and shown here natural size. portance the inspection semi- finished products, for instance bar billet stock, being shippedi from the steel producer’s plant. While the scope this paper mits only description and evaluatiom the most important the destruc-- tive and non-destructive methods, may interest draw attentiom the other available tests lating them follows respective classification. DESTRUCTIVE TESTS Macro hot acid etch test. Hardened fracture test. Microscopic test for Taper and stepdown hairline test. NON-DESTRUCTIVE TESTS Visual examination. tests. | ; he ~ 3 7 1 it € (a) test. (b) Magnetic permeability test. Electrical tests. Magnetic electrical tests. Radiography. (a) X-rays. (b) Gamma-rays. Visual examination. (a) Polished surface. (b) Coated surface. DESTRUCTIVE—NON- DESTRUCTIVE Micro-chemical examination. (a) Bauman prints. (b) Nissmer prints. The procedures the most out- standing these test methods, especi- ally they pertain the commercial classified one the outstanding and most reliable means for the de- tection hairline imperfections steel. These minute imperfections which, aside from the common defects such pipe, cracks, flake and objec- tionable segregation, ingotism den- dritic pattern, may recognized small, localized pinhole acid attack, are most readily observed the use HCl: H,SO,: H,O etching solution 160 180 deg. facilitate the inspection the etched specimen for hairline imperfections, detection hairline imperfections steel, will presented briefly. Destructive Tests The macro hot acid etch test procedure well the in- terpretation the results obtained are described very thoroughly the A.S.M. Metals Handbook (1936 edi- tion, pp. 573-579) and, therefore, unnecessary review this type destructive test detail. The test comparatively simple, the only diffi- culty being the possibility over- etching. However, the routine pro- cedure this examination requires special facilities for the the specimen (saw cutting, etc.) and suitable setup for the hot acid bath. With special care being exercised the preparation the samples and the judicious tim- ing the hot acid attack (to prevent binocular has been found material aid. The hot acid etch test, being defi- nitely destructive test method, most useful for the inspection semi-finished steel products for stance, for preliminary finish inspection billets and bar stock the steel plant, and for acceptance test purposes incoming steel the consumer. Microscopic Test For The basic principle underlying all microscopic examina- tions for non-metallic inclusion con- tent consists careful dry polish preparation representative longi- tudinal specimens (hardened condition recommended) and microscopic examination 100 diameters. The inclusions observed may reported either (a), the general overall con- dition which defines and describes the number, size and form the indi- vidual types non-metallic com- pounds, the segregation throughout the entire specimen under observation or, (b) the inclusion count method which estimates the number and sur- face area the inclusion per area the specimen. The results careful microscopic non-metallic examination sentative specimens are most useful the quality characteristic evaluation heat steel. Moreover, when- ever this examination presence so-called stringers and groups inclusions arranged chain-like form, may taken indication that the hairline fre- quency and severity rating will high. Yet, the reverse not true, for exceptionally clean metal, practi- cally free from non-metallics, often prone exhibit inferior hairline characteristics. general, has been found that material whose microscopic non-metallic examination shows reasonable number small, finely divided and evenly distributed non- metallics proves most satisfac- tory from hairline imperfection standpoint. Summarizing briefly, may stated that the interpretation any microscopic inclusion test only real value the determination hairline imperfections when used supplement the hot acid etch test. TAPER AND STEPDOWN HAIRLINE Test: The taper the stepdown hairline test when supplementing hot acid etch and microscopic non-metallic examina- tion, probably the foremost means under the classification “Destructive Tests” for the determination the hairline condition melt. The preparation, the examination and the evaluation the results the taper and stepdown tests have already been described, and only through experience that the tween these two types tests with the magnaflux test can established. lute requisite obtain truly repre- sentative test specimens. The taper test modification usually best suited for preliminary test purposes the steel mill, whereas, the stepdown method more adapted the finish acceptance testing bar stock, especi- ally where the dimensions the ultimate application the material are known. Due its tapered con- dition (usually in. 10in.), the THE IRON AGE, December 3 a | 4 q examination taper hairline test generally reveals greater number smaller hairline imperfections than the stepdown specimen. The number and size these defects are deter- mined the tapered slope the test specimen, and order observe hairline imperfection its entirety the normal taper in. per in.), defect in. length must possess depth dimension least 0.006 in. the other hand, the stepdown speci- men will reveal approximately the full length all imperfections occurring the particular surface any indi- vidual steps. The reason for the author’s prefer- ence the tapered over the stepdown specimen the fact that careful examination the former will not only give results the number and apparent length the imperfections, but will also indicate some extent the depth dimension the observed lines. Ed. Note: The concluding half steel ball with vis- ible hairlines. Etched hot 50:50 muriatic acid show hairlines more clearly. Mag- nified two times. this article will appear the near fu- ture. The author will various non-destructive tests for de- tecting and examining hairlines, and will also all his observa- tions and conclusions. Westinghouse Broadens Air Conditioning Line COMPLETE line “packaged” self-contained air conditioning units for commercial establishments, ranging capacity from tons and combinations tons has been announced the Westinghouse Three the Electric Mfg. Co. 36—THE IRON AGE, December 1938 units are central type and four are for installation within the conditioned space. Eliminating the hazards refriger- ation-cycle installation, all necessary for operation are power, water and drain connections. The NTERIOR view new Wes- Compactness feature, the unit oc- cupying floor space only ft. in. and other units the line are eas- ily winter air condi- tioning, and may used multiples provide tons. units are designed occupy mini- mum floor space and can car- ried through 3-ft. door opening. The largest measures only ft. in. ft. in. deep and ft. in. high. Light weight, obtained through com- pactness and elimination tion material, outstanding fea- ture. Five models have been added complement and complete the West- inghouse line self-contained units, which are now available 2%, 7%, and 15-ton ratings. These units may combined pro- vide multiples the given ratings, providing wide range capacities for commercial installations tons. Hermetically sealed compressors are employed the Two switches permit flexibility opera- tion; one controls the entire cooling mechanism and the other the blower motor that air circulation may enjoyed when cooling not necessary. all-steel welded form cabinet assures permanent rigidity. The units the new line are easily adapted winter air conditioning, installing the cabinets sary accessories such heating coil and humidifier, year round air condi- tioning available. t x q Bg va 4 { § * dd — . ]- Molding aterials for on-Ferrous ° FRANCIS ROWE David Brown Sons, Ltd., Sheffield ° ° ° subject molding mate- rials and methods for non-fer- rous alloys not one which ap- pears have received the treatment from technicians the past which deserved. Even though fair amount published literature available detailed phases non-ferrous foundry practice, there very little which cor- relates the whole, enumerates the various fundamentals which govern the choice one other the mul- titudinous methods variations pos- sible. sounds platitudinous repeat that the object any non-ferrous founder produce sound and homogeneous castings from various metals and ensure the same time that the physical properties the alloy the casting shall the best which that alloy the cast condition capable. achieve both these aims even the simplest shapes much more difficult job than many founders and most engineers realize. Could anyone undertake tomorrow cast block, in. square any alloy which could guarantee would 100 per cent sound and homo- geneous, and whose grain size, density *Abstract lecture presented before the Mid- land Metallurgical Societies, Birmingham, Eng- land, Oct. 13. view the Randupson molding process the Vulcan Mold Co. shows final mixture sand, cement and water falls into the molding box, which turn supported Hermann jolt machine supplant hand pneumatic ramming. and mechanical properties every case reached the maximum which that alloy was capable the cast con- dition? The author doubts it, and for one would not care try. Many founders could produce apparently sound casting reasonable density and high mechanical properties, but many respects would not 100 per cent casting. such obviously one ideal. There doubt, however, that non-ferrous foundry practice has pro- gressed enormously even the last two decades, and quite generally known how much the improvement molding materials and practice due greater knowledge metals. The most common material for molds for non-ferrous alloys doubt and always will natural bonded siliceous sands, used either the moist condition prepared for mold- ing, subsequently dried before cast- ing. recent years, there has been some substitution natural sands whose natural lack bond has been replaced the addition colloidal clays such bentonite, small proportion which gives very high green sand strength—higher than would permissible natural bonded clay sand, account the low permeability gases which such natural high clay content sand would possess. The use silica sands bonded with various resins, oils, gums and molasses has been common foundry practice for the last years. Such mixtures when dried have many ad- vantages and account these, some extension has taken place lately their use for molds distinct from cores. the field occupied molds made from sand, easily the most strik- ing development recent years the patented cement bonded sands. This process, originally developed for iron and steel castings has the last two* THE IRON AGE, December years made rapid strides the non- ferrous metal industry both for alum- inum alloys and the bronzes and yellow metals. The basis sand high purity silica sand mixed with ordinary Portland cement and definite proportions water. The resulting mixture air setting and gives molds extremely high permeability and great strength—of such strength that the ordinary box parts used enclose normal sand molds are not necessary. For many reasons, the sand mold possesses many disadvantages for non- ferrous castings, and overcome these the metal miold has been used for many years for those parts which reasons shape the quantity re- quired are adapted such method production. certain limited field also, development the way centrifugal casting has taken place recent years overcome the known defects and disadvantages the nor- mal sand mold. Methods Compared order review generally these various mold materials and the meth- ods connected with them, the author proposes split into two broad fields the advantages and disadvantages each method molding regards (a) physical properties, metallurgical properties and soundness the re- sultant casting, and (b) cost and rapidity and ease production. The two things are not necessarily cor- related, one may certain mold material order reduce costs one may take for other reasons whether the cost greater less. fairly exact generalization that the more rapidly alloy cooled the mold, the higher will the density, hardness and general soundness the casting. While exceptions undoubted- exist, this holds for all but special cases. The rapidity freezing any one casting mold fairly obvi- ously depends two things the thermal conductivity the mold mate- rial and the temperature which the metal fills the mold. This, generally known the casting temperature, within certain limits, and might thought the uninitiated that the minimum casting temperature meeded completely fill the mold would the best employ most However, practice this does not always prove true, imperfec- tions molds and mold materials are such that less sound castings may re- sult from the employment very low casting temperature than one somewhat higher, and impossible 38—THE IRON AGE, December 1938 for this reason lay down dogmatic rules the best casting tempera- ture for any particular alloy par- ticular class casting. regards the mechanical proper- ties non-ferrous castings gen- eral, can safely said that non-ferrous foundry practice more castings suffer from high casting temperature than low, attention molding technique and particularly runner and riser prac- tice would permit lower casting tem- peratures employed and there- fore quicker freezing the metal and generally higher density and physical properties. Even other advantages follow its train, two which are worthy some slight mention. The dangers incorrect melting practice for any non-ferrous alloy are too well-known for further detailed ex- amination given. This has been the subject great deal discus- sion during the last ten years. One the dangers and inevitable results melting any alloy the ab- sorption gases, and the amount gas absorbed rises enormously with rise temperature the metal above its freezing point. Usually, and cor- rectly, lowering the average cast- ing temperature means lowering the temperature which the metal raised prior pouring, which its turn lowers the amount gas ab- sorbed, besides lowering oxidation volatilization losses. Secondly, the gas which inevitably absorbed alloy liable given off the moment solidification unless special inhibitors are employed freezing very rapid. Therefore pinholing similar troubles alloys are less, the more rapid the freezing, therefore the employment the lowest prac- ticable casting temperature ful effects apart from the lower grain size and higher density. Obviously from the point view thermal conductivity, the sand mold distinct disadvantage, and where the piece cast lends itself the use metal mold, such usually pre- ferable. The disadvantages sand molds this direction are much greater where the castings are ap- preciable mass. the case very light sectioned castings, the vantages the metal mold may confined quicker cheaper pro- duction, greater accuracy and sharpness the resulting castings. frequent practice non-ferrous founding use mold constructed such manner that differential rate freezing takes place differ- ent parts the casting, usually compensate for differences mass sections the castings, ensure great soundness hardness vital points. This course the method known “chilling” where material high thermal conductivity usually steel cast iron incorporated the sand mold the points where such densening required. Steel cast iron chills mass varying with the effect required are more usually employed, but the use copper graphite are for increasing decreasing the differential between the chill and the sand. Both have been employed for special jobs with marked success not attainable the use cast iron steel alone. with the use chills however, sand molds not give results equal those ob- tained from metal molds and though their use inevitable great many cases—particularly the high melting point alloys—efforts should directed always the direction securing the highest thermal conductivity sand molds putting runners and risers such positions and such dimensions will enable low casting tempera- ture used, and using chills the thicker portions the castings points where great soundness es- sential. Randupson Process passing, should mentioned that one the minor advantages the Randupson process cement molding that the molds have defi- nitely higher thermal than ordinary sand molds. This obviously trend the right direc- tion. While way comparable metal mold, the difference com- pared with ordinary binders quite noticeable. Centrifugal casting some form other has been practiced for nearly 100 years, but far records go, the firm with whom the author con- nected, pioneered and commercialized the vertical axis mold and the meth- ods used for gear wheel blanks and similar parts. For reasons outlined previously, the advantages rapid freezing and metal mold have been known for great length time. Metal molds bring some disadvantages since high density the metal ac- companied high liquid shrinkage, and, where freezing rapid, extra provision for feeding must made compensate for the heavy shrink- ages. This difficult matter metal molds and may result some the mold being offset the increase mass the castings, owing the heavy feeder heads. centrifugal casting, however, the action such that metal being continually fed centrifugal force into the freezing castings and, providing conditions are right, auto- matically compensating for the liquid shrinkage. Another advantage centrifugal casting one which not usually anticipated. well known that fine grained castings have usually more desirable mechanical properties than coarse grained ones. The con- stant vibration and agitation centri- fugal castings during the whole period solidification prevents the growth large crystals, with the result that the casting even finer grain than stationary casting made under simi- lar conditions, that is, regards mass and casting temperature. Another ad- vantage centrifugal casting that the difference physical properties between small casting and one sand even chilled castings. is, course difficult and expensive obtain data this point since bronze castings the order one-half one ton weight are expensive cut up. While most the statements given far regarding centrifugal castings refer castings cast molds with vertical axis, similar results are ob- tained the horizontal axis mold which, however, more limited configuration the parts which can produced, being largely confined concentric bushes and the like, flanged otherwise, but with plain bores. illustrative the practical advantages accruing from such methods there are many authentic records increase life and load carrying capacity per cent over sand castings similar composition, apart from such obvious advantages much less variability between one casting and another. Turning some discussion cost, ficult generalize. Small light cast- ings, where the quantity not suf- ficient justify metal mold the alloy shape the casting not one which lends itself readily such production, will continue made the green sand method molding. For cheapness, and ease and rapidity molding, hard beat. Where important castings anything above the lightest weights are concerned, most bronze foundries prefer dry sand mold account the greater strength and reliability such molds. With the increasing use sand con- trol, both regards grain size, per- meability, moisture content, etc., and particular with the advent sands bonded with colloidal clays, there doubt the field for green sand work could increased. The green sand mold possesses undoubted advantages giving sharper casting with smoother skin and less flash, and thus less fettling costs, and its extension more important work the use synthetic sands, promises very favorable field. The advantages properly made synthetic sand are that the permeability greater and more regular than normal green sand, and that much greater strength can obtained. Owing its revolutionary and spe- cial features and the rapid inroads making the non-ferrous indus- try, the author proposes make rather fuller reference than has been devoted other known molding methods and materials. The process the invention French engineer and has been devel- oped over the last six years France. During the last few years has spread abroad and foundries every country Europe and the United States are using for all types castings every type metal. Ce- ment sand medium for cores had been proposed and tried far back 1898, but, owing inappreciation the fundamental scientific principles its use, was never extensively used, and was commercially abandoned for period years, until Durand the Cie. Randupson, investigated the scientific principles and commer- cialized its use. Properly made cement sand molds have much higher per- meability than any other type mold and possess extraordinary strength, even very large masses. Primary Hydration Only mentioned previously, the basis sand silica sand high purity, containing about per cent silica and upwards, and grain size deter- mined for the class work being made. This mixed with from per cent ordinary cement, ac- cording again the type casting and metal, and sufficient water added ensure primary hydration the cement only. This important factor. water added sufficient completely hydrate the cement, then the permeability the finished mold very seriously reduced, material unsuitable for molds resists the passage gases. Owing the high strength the finished molds, ordinary cast iron steel box parts are not used, but wooden chassis are used ram the molds and these are withdrawn with the pattern when the pattern moved. The process this respect corresponds therefore the all-core method molding. Molds, during the process ramming, are suitably re- inforced with straight irons in. in. diameter, according the size the mold, and the mold suf- ficient size need crane handling after set, staples are embedded for this purpose. One the greatest advantages the process the speed with which molds can rammed. The usual molding time from per cent per cent that required ordi- nary methods, the greatest saving be- ing with the largest and most compli- cated molds. After ramming, the pat- tern withdrawn the usual man- ner and the mold finished and set aside set. This setting takes place the open normal temperatures and takes from hr., according the size the mold, the precise mixture and type sand, and the atmospheric conditions the shop. Setting proceeds only slowly tem- peratures below deg. F., but with great rapidity deg. F., and above. Most molds are sufficiently set lift their own hooks staples after hr., but large molds the moisture not thoroughly absorbed until hr. have elapsed. For steel, all new sand used for facing account the high refrac- tory properties desired, but for iron, bronze, brasses and light alloys, all old reconditioned sand can used. For steel, wash paint required, but for other metals, coating blacking other type coating usually employed, and applied after setting ensure good skin. The two more portions the mold are put together and clamped any suitable manner. After casting, the mold broken and the sand passed through crusher and stored ready for re-use after, course, add- ing further proportions cement and water. The disadvantages the proc- ess should briefly enumerated: (a) the sand has green bond strength, (b) the time required for air setting usually hr., (c) the sand must used from hr., and (d) all sand must through the mixing plant both originally and for recondi- tioning. The advantages, however, for work which adapted, far more than outweigh these disadvantages and the savings labor costs are par- ticularly striking, apart from the tech- (CONTINUED PAGE 75) THE IRON AGE, December 1938—39 e n | new mechanical cupola charging equipment recently in- stalled the Ferro Machine Foundry Co., Cleveland, has enabled the company obtain substantial re- ductions the cost charging raw material into the cupola. interest- ing phase this installation the use yard crane load and weigh the charges without intermediate handling operation. Previous the installation the new equipment, was necessary handle incoming raw materials several times; from the railroad car the storage piles, from storage piles elevator, etc. With the present setup most the iron loaded into the charging buckets directly railroad cars, thus eliminating the pos- sibility demurrage charges and one series handling operations. Limestone and coke are dumped from the incoming hopper cars into under- ground bins below the elevator shaft 40—THE IRON AGE, December 1938 where the cupola chargers pick them up. Yard Equipment the accompanying photographs illustrate, the equipment for handling the iron supplies consists yard crane equipped with magnet, heavy duty scale with the dial mounted the same height the crane cab, automatic turntable and roller con- veyor leading and from the area served the cupola charging cranes. The scale used this installation manufactured the Atlas Car Mfg. Co., Cleveland. Scale Dial Level with Crane Cab The five-ton yard crane, product Shepard-Niles Crane Hoist Co., Montour Falls, Y., has span ft. The operator’s cab fixed the cross beam, thus keeping the oper- ator always adjacent When not loading charging buckets Mechanical IG. photograph gives comprehensive view the man- ner which the charging setup functions. The magnet posi- tion deposit load pig iron into empty bucket through the centralizing funnel. loaded bucket the end the loaded conveyor being attached cupola charger. Note the visibil- ity the scale dial. the crane can used for unloading materials from freight cars storage areas. During the charging periods the buckets are deposited empty upon one section Mathews heavy duty gravity conveyor from whence they roll into position under the large steel funnel where the buckets are loaded and weighed. The funnel acts cen- tralize the magnet load when re- leased and prevents material from fall- ing outside the bucket. the Atlas scale dial mounted location where will clearly visible and relatively close the operator’s cab, the operator quickly acquires skill handling the magnet which enables him load the buckets with surpris- ing accuracy while watching the scale. Scale Mounted Turntable The roller conveyor the scale platform mounted automatic 7 . Equipment Lowers Charging Costs Cleveland Foundry turntable operated compressed air. After the bucket has been loaded, the ground operator, whose function unhook empty buckets and hook loaded buckets the charging crane, oper- ates valve, causing the turntable move into line with the loaded bucket conveyor. Sumultaneously veyor mechanically tilted that the loaded bucket runs off the scale and down the loaded bucket section the conveyor, finally com- ing rest under the charging crane. Ample storage space for loaded buckets provided under the charg- ing crane area. Brake stops along the conveyor also allow for bucket storage and permit only one bucket time occupy the scale platform. Two Shepard-Niles monorail cupola chargers, each with three tons’ capac- ity and utilizing bottom dump type buckets, are used this installation. Switches each cupola enable one charger placing load the cupola stack while the other charging crane picking load. The coke and limestone are charged separately. The Atlas scale incorporated into this arrangement the same heavy duty, all steel scale used Atlas blast furnace cars. The scale’s indi- cating dial can equipped with elec- trically operated remote i 2—This view equipment, taken from another angle, shows more clearly the details the tion. the fore- ground loaded bucket position crane, while the back- ground can seen empty bucket the scale platform being loaded cording devices either the graph type printing patterns. the Cleveland foundry’s present rate production, approximately 200 tons are handled across the scale eight hours, but occasion 240 tons have been handled eight-hour stretch. other foundries that have recent- modernized the handling raw materials, scale cars are combined with magnet loading the iron yard. the foundry Caterpillar Tractor Co. the iron charging means the crane with the magnet, while the stone and coke are weighed out scale cars. THE IRON AGE, December ° ° raw zinc alloy die casting for the new Plym- outh instrument board. This view shows the casting with front panel ground and edges trimmed. The next operation copper and nickel overall electroplated coating. Case History the Finishing time time trade literature describing the general practice finishing zinc alloy die castings. Specific data, however, rare, and for that reason the belief that would interesting and in- structive present the exact details the practice used one particular part. For this purpose the glove com- partment door the Plymouth automobile was selected. This one several die castings which add the attractiveness the instrument board arrangement this car. have appeared from The door question slightly curved plate finished with grained organic film the main panel and with red lacquer stripes nickel plated relief. The sequence opera- tions involved follows: copper plate, nickel plate, spray ground coat. bake, apply wood grain finish, bake. spray clear lacquer over wood force dry, polish lacquer, apply red lacquer, force dry, spray back, apply finely divided felt, bake. The casting this particular case was made the Alemite Die Casting Mfg. Co. Woodstock, and the plating and organic finishing steps were carried out respectively Mahoney and the Briggs Mfg. both Detroit. Dr. Heussner the Chrysler Corporation very kindly cooperated obtaining permis- sion use the information. The castings are received the Mahoney plant with the edges trim- med. The center panel, which ordi- narily receives the grained finish nor- mally ground the Alemite plant. the Mahoney plant the castings are inspected and are then polished the areas which are appear nickel relief. This accomplished with in. sheepskin wheels revolving 42—THE IRON AGE, December 1938 mesh emery affixed with animal glue provides the abrasive surface. polishing. padded buff consisting alternate wide sections in. diameter and wide sections in. diameter used. The combina- tion this padding with the absence stitching makes very soft buff. The buffs are nominally in. diameter but are allowed wear down in. before they are transferred use nickel coloring. The wheels revolve 1800 r.p.m. and Stief- fen’s 100 per cent saponifiable the buffing operation the areas appear nickel relief are given par- ticular attention. main panel, however, also buffed, although attempt made eliminate complete- the original grinding texture. The partial buffing seems minimize plat- ERE the front the cast- ing completed. clear has been ap- plied over the grain coat and red lacquer applied the grooves ° ° view shows the glove compartment door with ground coat applied and baked for best adher- ence. The following step design the panel. ° ° ° Zinc Alloy Die Casting ing difficulties this area. The parts are then ready for plating. The first step the cleaning opera- tion prior plating scrub the parts gasoline. This removes con- siderable proportion the buffing grease and insures that the recesses and crevices are free from packed compound. The parts are then racked and are cleaned electrolytically cathodes for sec. and then anodes for sec. per gal. solution Wyandotte SM-6 cleaner operated 180 190 deg. The cleaner tank made steel and acts one elec- trode the electrical circuit. Following the cleaning, the work rinsed running cold water re- move adhering alkaline cleaner solu- tion and then dipped for sec., until definite gassing develops, temperature 15-per cent hydro- chloric acid solution, following which again rinsed remove the adher- ° ° back the door shown here sprayed with adhesive and fan- flocked resemble felt. ing acid. The rinse tank used after the acid dip separate from that used after cleaning. The work then ready for copper plating. Mahoney uses the cop- per-nickel system plating and util- izes the Rochelle salt-copper cyanide bath. The metal content the solu- tion held oz. per gal., the free cyanide 0.6 oz. per gal., and the Rochelle salt oz. per gal. carbonate added the new solution but the entire contents the tank are discarded when the carbonate content builds oz. per gal. use. The The tank used copper plating the glove compartment doors unlined steel 740-gal. capacity. The work agitated the rate strokes per minute, each stroke covering forward and return motion each in. The anodes are copper balls held steel cages and the nearest distance between the work and the anode in. in. The current density used not measured but sufficient produce 0.0003 in. min- imum coating min. plating. Following the copper plating opera- tion the parts are rinsed cold water and are then dipped briefly cold deg. Bé. sulphuric acid solution neutralize any adhering cyanide solu- tion, after which they are again rinsed cold water and placed immediately the nickel plating tank. The nickel plating solution used the Harshaw XXX bath which contains essentially oz. per gal. nickel sulphate, oz. per gal. nickel chloride and 5.5 oz. per gal. boric acid together with vari- ous brightening and wetting agents, the nature and amounts which are plant secrets. The solution operated THE IRON AGE, December 4 | { ope | 3.7. contained rubber lined steel tank 740-gal. capacity equip- ped for agitation the same speed the copper tank. The anodes are Harshaw Chemical Co.’s placed give minimum distance be- tween the nearest ancde and work sur- faces 3.5 in. in. Plating continued for min. current density sufficient give minimum thickness 0.0007 in. nickel the thinnest point. Following the nickel plating opera- tion the parts are rinsed cold water, then hot water and are allowed dry. The water stains produced drying are removed light coloring operation using the 10-in. wheels dis- carded from the zinc buffing opera- tion. The wheel speed 1800 r.p.m. and the abrasive, used sparingly, mixture lime white and rouge marketed for the purpose Stieffen. The nickel plated sufficiently g