The Iron Age 1929-05-09: Vol 123 Iss 19

THE AGE New York, May 1929 ESTABLISHED 1855 VOL. 123, No. Steel Yoke Liberty Bell Liberty Bell, priceless relic Revolutionary days, has been protected from damage through the possible failure its yoke. Dry rot the 176-year-old timber was discovered Charles Neeld, director public property the City Philadelphia, and asked the engineers the Franklin Institute, Philadelphia, decide what should done reinforce the wood. Steel castings were put place the top and bottom the yoke and connecting bolts were embedded the wood, that only the surfaces the reinforcing plates and the nuts are visible. Casting, Hidden within the Weakened 176-Year Old Timber, Designed Serve Indepen- dently the Wood The supporting steel casting weighs lb. and capable holding the bell alone, should the wood rot away entirely. The capacity the yoke, since being strengthened, about 10,000 and the bell weighs only 2080 Ib. The foundry work was done the Crucible Steel Cast- ing Co., Lansdowne, Pa. Howard McClenahan, secretary the Franklin Institute, appointed the engineers who developed the plans for reinforcing the yoke and designed the supporting casting. They included Benjamin Frank- lin, chairman; Hugo Bilgram, Charles Bonine, George Crampton and George Hoadley. Passing Through the Wood, Connect the Steel Casting the Top the Bell Yoke with Plates the Bottom Section LAN, Side Elevation and Cross-Section the Supporting Steel Casting Used Reinforce the Yoke the Liberty Bell 4 = 4 1271 Working Rules for Nitrogen Hardening High and Low Temperature Cycle Gives Deep Case and File Hard Surface Eighteen Hours ONSIDERABLE publicity has recently been given the process nitrogen hardening and usual with such publicity, immediate and wide- But the the case) spread adoption this process was predicted. subject developed slowly (as also generally and was found that the special steels were high price, hard get, and the process required very long time with uncertain results. Metallurgists investiga- tion found that was adaptation much older process special steel; CQUAID* with small percentage molybdenum added in- crease the toughness. The exact status these steels somewhat uncertain. Much work has already been done develop improved steels for nitriding; many new steels will doubtless developed the next few years. The strength the fin- ished article course de- pendent upon two factors, viz., the strength and tough- ness the hardened surface and the strength and tough- ness the core after the nitriding operation. the not much the proc- 975 Deg tremely brittle, load which ess, but the addition fractures the surface will aluminum the steel transferred the core adapt the process. quickly that the latter Adolph Machlet, the certain break immediate- American Gas Furnace Co., ly. When the core has been was granted patent properly toughened, and June, 1913, for hardening large proportion the heating ammonia case, the case will crack Fahr. This process had only limited application with ordinary iron and steel; extreme- hard non-corrosive sur- face can obtained, but the hardened zone thin that does not offer much resistance abrasion, even under relatively low unit pressures. Where unit pres- sures are very light and re- sistance desired, the Machlet treatment can used advantage. 1924 Adolph Fry, the Krupp company Ger- many, discovered that the addition aluminum, chro- mium, several other metals the steel hardened resulted much deeper zone hardness. insisted that the results obtained would not commercially satis- factory done temperature higher than 1075 deg. Fahr. described him, the process required about hr. 950 deg. Fahr. produce satisfactory case. Even the lower temperature, the case was extremely brittle. The name “nitriding” was given the process, which indicates that the hardening due the forma- tion metallic nitrides iron, aluminum chromium. was found later than the addition small amount molybdenum would materially reduce the notch brittle- ness the nitrided piece, and the present time prac- tically all the nitriding steels contain molybdenum. Some the special nitriding steels contain only molybdenum and aluminum. Others contain chromium and aluminum above 900 deg. so Hardness-Depth *Metallurgist, Timken-Detroit Axle Co., Detroit. The article abstract paper delivered before the Western Society Engineers, March 18. 1929, The Iron Age Curves Cases Made Under Different Conditions and the core will bend, type failure seldom found pieces case-hardened the conventional method heating with carbonaceous materials. The core strength the nitrided piece depends upon the alloy and the carbon content. For easy machin- ing prior hardening desirable have the car- bon content low, but for high core strength and the best nitriding results, desirable have the carbon relatively high. har- monize these diverse requirements, nitriding steels carry from approximately 0.30 0.50 Before nitriding, these special steels will show yield point varying from 125,000 160,000 lb. per sq. in., depending upon the carbon content and the heat treat- ment. After nitriding 1200 deg. Fahr. the core strength reduced. matter fact the strength the case really controls the strength the part. Yet has been the writer’s experience that very few engineers, when designing parts made from case-hardened steel pay any attention the special physical characteristics the hardened surface, but blissfully make calculations based upon the estimated core strength, and neglect entirely the fact that the case fails the part must replaced. The cost steels for nitriding higher than those used for ordinary case-hardening. the present time one the best known and well advertised nitriding steels quoted approximately 12c. for small lots, and down 7c. for requirements 1000 tons per annum. This compares with approximately 2c. for low- Nitrided for t $ | ‘ ‘ ‘ | if i = JY carbon and 4c. for the better grade alloy case-hardening steels. But there are many places where the losses case- hardened products, due soft spots warpage, are sufficient justify the higher cost the nitriding steel, with its lower losses the finished article. When nitrid- ing steels compete with the higher priced monel metal and stainless steels, for pump shafts and valve seats, the total costs are greatly favor the nitriding steels. This particularly true where hardness elevated tem- peratures also important factor. Time Process Varies ITRIDING usually consists subjecting the parts where between 900 and 1200 deg. Fahr. The time varies greatly, depending upon the temperature, the materials used, and upon the use which the completed article put. varies from low one hour much 100 hr. Best results are obtained when the nitriding steel sorbitic condition, obtained quenching from above the critical range and then drawing below the critical range (generally from about 1100 deg. Fahr.). The ductility the finished article then greater, and the nitrided case has much less tendency spall. The surface the piece must also clean; since some un- known varieties foreign matter exert great influence upon the results best prescribe thorough clean- ing either boiling caustic solution gasoline. Sufficient material should have been machined off re- move any decarburized metal produced during rolling, forging, heat treatment. The retorts which the work treated with ammonia should made from material which does not nitride easily; they are usually made high nickel alloys such nichrome. Inasmuch ammonia expensive well irritating, the retort should sealed tightly possible with special cover, clamped down gaskets asbestos nickel. the Timken-Detroit Axle Co., satisfactory seal obtained with heavy nickel sheet for cover, clamped down the machined surface the retort, using small amount sodium silicate seal. some vertical furnaces the cover has oil seal, and the work placed baskets. This facilitates loading and unloading. designing the nitriding department, provide good faeilities for eliminating the ammonia fumes, since they are very irritating and drive the workmen out. Insure tight connections from the ammonia tank through the retort; escaping ammonia from the outlet pipe should discharged into small stream running water. the retort taken out the furnace, special care and sealing devices are necessary; the furnace must also tightly closed when the retort place. the Timken- Detroit Axle Co., the retort provided with tracks the bottom run nickel-chromium rollers, and thus move them from the loading position front the furnace into the hot chamber. and outlet pipes for ammonia are brought down close the front the furnace, and asbestos mat provides the tight seal under the furnace door. Use Sealed Retorts the articles are placed loosely furnace heated with electrical resistors, well remember that the resistors will much higher temperature than the other metal the furnace, and thus the dissociation the ammonia increased. Also remember that considerable time lost necessary cool the work the furnace. This quite necessary the work loose the baskets, but not necessary the steel placed movable retorts (unless the “high and low temperature method” described later employed). avoid long delays cooling system should provided reduce the furnace temperature rapidly possible; this will save from two four hours per run—a very important consideration. Commercial ammonia, which can obtained most cities 100-lb. tanks, very satisfactory. The usual method pipe the ammonia through reducing valve the retort rubber hose and thence water seal which indicates the pressure maintained the retort (ordinarily about one inch water). The flexible hose allows the retort moved without breaking the con- nections. The ammonia tank should have pressure gage the reducing valve; the tank must placed that liquid ammonia will not enter the system. Circulation Speeds Work process can speeded circulating the am- monia through the work. Apparently the surface the work tends become passive unless fresh ammonia continually comes into contact with it. handy circulat- ing device, due the Leeds Northrup Co., adapta- tion the “Homo” furnace for nitriding. This furnace contains circulating fan which reverses its direction regular intervals, and hence keeps rapid flow and continuous agitation the ammonia through the work. When ammonia heated contact with iron, dis- sociates into hydrogen and nitrogen extent depend- ing upon the temperature; this effect should kept certain minimum. Whether the important factor hardening the dissociation the ammonia the flow the ammonia not certain, but seems that con- stant degree dissociation not important factor. If, then, contact between the work and undissociated am- monia are the most important factors, the percentage undissociated ammonia the retort and the circula- tion should under control. further follows that with high degree circulation the dissociation can relatively great without any adverse effect the work itself. Thus have found that nitriding 1200 deg. Fahr. (where the dissociation hard keep below per cent) satisfactory providing the flow ammonia through the work sufficiently rapid; satisfactory results have also been obtained with not more than per cent undissociated ammonia the retort. simple appa- ratus should set determine the percentage undissociated ammonia coming from the retort. Combination Cycle Gives Best Results temperature above 1075 deg. Fahr., else the mar- ginal layers will brittle and tend peel off. For this reason, most nitriding being done below 1000 deg. Fahr.; the time required often much 100 hr., and the resultant nitrided zones are relatively thin but ex- tremely hard. possible obtain good results higher tem- peratures; fact, some the toughest and most satis- factory cases have been nitrided 1200 deg. Fahr. has been experience that the temperature increases from 900 1250 deg. Fahr. the surface hardness de- creases, but the depth greatly increased. Twenty hours 1200 deg. Fahr., while does not give case which hard would obtained the lower temperature, will give very much deeper one than period say hr. 950 deg. Fahr. The figure shows depth-hardness curves determined the Timken-Detroit Axle Co. Here use 10-hr. period 1200 deg. Fahr., followed hr. 975 deg., which produces Brinell hardnesses high 1200 the surface and 800 0.015 in. below. the ammonia circulated, the time can still further reduced 6-hr. period 1200 deg. Fahr., followed hr. 975 deg. Fahr., and total cycle The Iron Age, May \ 4 approximately hr. the main object non- corrosive surface, such pump shaft, the nitriding cycle can reduced few hours. Molybdenum-alumi- num steels seem require higher temperature than the chromium-aluminum steels. the surface the finish must free from dis- coloration, will necessary cool the work am- monia down not more than 350 deg. Fahr., else the pieces will have blue oxide finish, which itself fter than the nitrided case beneath. When removed from the nitriding furnace retort the work should light silvery gray, very smooth and absolutely file hard. This one the best indications good results. dusty powdery finish indicates that cleaning the surface circulation the ammonia has been neglected. the surface satisfactory, but very thick and under- laid with very soft zone, because the hydrogen has been more active than the nitrogen, and circulation the ammonia has been too sluggish. The surface should not only hard, but tough. The edges, they possess even very slight radius, should not flake when pounded with hammer, and flat surfaces should resist the peen end without cracking. sec- tion ground and etched nitric acid solution, the nitrided case will developed and its total depth can ascertained easily. depth indicated the etch is, however, not indicative the actual depth file-hard material, this seldom more than 0.010 in. Careful measurements will show that warpage com- mercially negligible, even with intricate parts, although nitriding increases the size approximateiy 0.001 in. per in. diameter. This growth quite uniform, and can allowed for the design. Nitriding can done any part subjected heavy abrasive loads, and fact where even case-hardening now used, with the possible exception heavily loaded carburized parts now made such steels 5-per cent nickel steel. Nitriding steels are less resistant con- centrated shock loads than are the high-alloy case hardening steels, but such parts wrist pins, timing gears, worms and journals, the nitrided article superior the case-hardened article. everyday commer- cial production parts such pump shafts, vacuum- cleaner beater bars, valve seats withstand high tem- perature and pressures; for airplane engine timing gears and hundreds parts requiring the highest degree hardness with the least distortion. One consumer alone requires approximately six tons nitriding steel per week satisfy his requirements. For such parts bearings and gears which now use most the case-hardened high-grade alloy steel, nitriding has still successfully demonstrated. remarked above, nitriding steels are much more difficult ma- chine due high alloy and carbon content. However, several well known European automobiles are said contain ring gears and pinion nitrided chrome-alumi- num steels. must admitted that some very poor results have been obtained with nitriding, but believe this has been because some simple factor the process neglected. also well remember that the nitriding art its infancy. Equips Drilling and Hobbing Machines with Safety Devices the drilling pieces made special steel, one the departments the General Electric Company’s River Works West Lynn, Mass., encountered considerable difficulty from flying chips. These chips were continual source danger the workman the machine and also passersby; addition the fallen chips scattered upon the floor proved dangerous well unsightly. These hazards were eliminated applying the machine the ad ¥ q > 4 f i — 1929, The Iron Age chip breaker and guard here illustrated. The guard pre- vents the chips from scattering, while the chip breaker keeps them one position the table. bullet-proof shield for hobbing machines has also proved effective. This device, used the company’s Pittsfield Works, serves protect the operators from flying particles the hob mold case. Previously the sight holes were covered with expanded wire mesh, but this was found interfere with visibility, and fail provide complete protection. Since the installation the protective window bullet-proof glass two serious acci- dents have been averted. one these cases piece hob, shown the right-hand side the handle the illustration herewith, shattered the inside, but not the outside lamination the glass. The Chip Breaker and Guard Left Eliminates Hazard Flying Chips Drilling Special Steel. serious acci- dent was averted the bullet proof glass shield, above, installed hobbing machines | | 4 P Principles Materials Control Forecasts Based Performance and Schedule Need Frequent Revision—Effect Engineering Changes HOWARD URING the past ten years intense interest inventory turnover has manifested itself. One the results has been the development so-called hand-to-mouth buying. Thus new phase business conduct has come form important part manage- ment, and the systematic purchase and delivery mate- rials has become one the vital functions every man- ufacturing concern. Where formerly was believed suf ficient have plenty material all times, now de- manded that not only must always have sufficient, but that must never have too much. Such conditions cannot attained without careful planning. this end, has become the practice most manufacturers formulate advance tentative pro- gram for each year’s output. This necessary provide new designs, plant equipment and personnel, well make provision for materials. Were possible make such plans accurately, these problems would become simple. But, unfortunately, few can predict the future course business year ad- vance, and becomes necessary revise estimates from time time. there has been developed the idea monthly forecasts. Forecasts Three Months Advance Many raw materials have purchased three months ahead time, these forecasts usually include the prob- able requirements that far advance. The data for these include figures from the field organization the sales department and the quantities sold corre- sponding months former years. Every item informa- tion the command the organization utilized formulating the forecast. Each month the forecasts made the previous month are reconsidered, and necessary revised, that there really are three forecasts each month’s business. The first two are used for purchasing information, and the last plan production and deter- mine delivery dates. These forecasts are terms finished units models. such they are use the purchasing department. the duty the material control department trans- late them into purchasable items and determine the quantity each bought. They must know how many castings, forgings, stamp- ings, ete., are required for each unit and how much the various kinds bulk stock will needed. This in- formation must sent the buyers with the least pos- sible delay. over blueprints each time would re- quire too long. Therefore, they have recourse parts lists furnished the engineering department and usage record showing the quantity bulk stock needed for each fabricated part, the latter usually furnished the pro- duction engineering department similar organization. addition the quantities needed meet the fore- advisory staff, General Motors Corporation. Detroit. This paper was delivered May Detroit, before the Management and Materials Handling Divisions the Amer- ican Society Mechanical Engineers. cast, there are service requirements, replacements for scrap and other extraneous items, all which must listed and combined. this point becomes necessary describe briefly the clerical methods involved keeping track material transactions. The main functions observed are: Compute requirements all kinds, Cover the requirements with purchase requisition, Determine delivery dates, Receive the materials, Disburse them the factory, Keep records all diversions for service, scrap, consequence the following data must available all times: Quantity each item required, Quantity each item requisitioned. addition this information, necessary know certain times Quantity each item received, Quantity each item disbursed for pro duction, service, etc. make economical division labor, these figure are usually embodied two records. The more important and the more difficult work done highly trained men and consists items (a) and (b), requirements and requisitions. Receipts and disbursements material are recorded from receiving sheets, scrap tickets, shipping re: ords, less experienced men girls. The first record known the requirement record and the second the stock record. highly desirable maintain all records pure mathematical basis, and that end the cumulative method general use. This cumulative principle sim ply means that, instead regarding each requirement individual problem, carried all through the vari ous steps ordering, receiving and disbursing, all quirements for the same item are added together recur from time time, and totals thus built are main tained comparative basis. These accumulations from one two points, either Jan. the commence ment manufacturing season. the use this cumulative method the following facts are always avail- able: Total requirements less total requisitions are quantities ordered meet schedules. Total requisitions less total receipts are open orders. Total receipts less total disbursements are inventory figures which may checked physi- cal counts. return now the requirements computed from the forecast and service requisitions. Each requirement for production entered its appropriate card the requirement record. There may several entries made for one commodity, used more than one model. These are cumulated form production total. this The Iron Age, May 7 total are added requirements for service and allowances for scrap form gross total requirement. requisition then made equal this gross total requirement and sent purchasing department. Each month when new schedules are broken down the production requirements are added the previous produc- tion totals and these cumulatives, added the new cumu- lated service requirements and scrap replacements, form new gross totals. Comparison the new gross total re- quirements and previous total requisitions shows the quan- tity necessary buy. Keeping Track Stock materials are received the plant they are entered the stock record. These entries also are carried cumu- latively. Thus. the total receipts shown the stock record are subtracted from the total requisitions shown the requirement record, the difference indicates open orders. some plants desirable know the quantities raw stock. When this so, all disbursements from stock factory are entered the stock record and cumu- lated. The disbursements service and those for the re- placement scrap are entered and carried the same way. The difference between the total all these dis- bursements and the total receipts the balance raw from this record that disbursements for scrap are obtained, included replacements the require- ment record. When necessary know how much any com- modity the entire plant, total shipments are broken down and the individual items added disbursements for scrap, service, etc. This total subtracted from total re- ceipts gives the desired total the plant. Similarly, the total shipments plus total scrap, subtracted from total dis bursements the factory, gives total work process. Necessity for Monthly Revisions Requisitions sent the purchase department are many them for material needed several months later. De- livery dates are carefully specified, but even the most con- scientious consideration cannot indicate these shipping dates with perfect accuracy, due inevitable changes schedule, and they have revised from month month. The foregoing brief outline the principal routine functions the material control department regards productive materials. The handling expense items similar. Many them are direct proportion produc- tion schedules. This includes such commodities drills, reamers, standard cutting tools, lubricants, cutting com- pound, wiping rags and rubber gloves. Supplies various kinds are customarily handled maximum and mini- mum basis. This not the occasion for more detailed descrip- tion. stated, the object relate the engineering de- partment these activities. Effect Changes and Irregularities This sketch what goes the material control almost ideal the light actual procedure. reality, probably one-half the work performed the de- partment brought about changes and irregularities various kinds. The two leading causes extra work are schedule changes and engineering changes. Schedule changes are generally due unlooked for business condi- tions. They frequently cause much work entirely new forecast. Engineering changes, far the material control concerned, are two classes: those which can put into effect when convenient future date considerably advance, and those which must made immediately. 1929, The Iron Age The first class causes little trouble beyond the work inci- dental balancing out the raw stock and work process. The second class the bugbear the department. many instances material order has canceled, and new material secured. often happens that this diffi- cult accomplish and the results are not satisfactory. Lack Coordination Frequent the average material control department today realizes that without change cannot progress, en- deavors treat the matter philosophically. There has been marked improvement the methods transmit- ting engineering changes and handling them when received. The greatest difficulties which still exist any extent are caused lack mutual understanding the problems and methods the two departments. sometimes hard for the material control under- stand why changes are necessary after year experi- menting, and equally hard for the engineering department understand why some apparently insignificant change should affect the material situation. The best solution date the appointment man who has had actual experience both departments, perform definite set duties, follows: Act consultant for engineering depart- ment when changes are contemplated. Interpret all changes actually determined upon the material control department. Embody these changes material control records. Maintain close observation bulk stock scrap the factory, resulting from punch press, screw machine and similar operations, make sure that the most economical sizes the bulk stock are being used. Watch the factory operations general see that they are done accordance with stand- ard practice. Familiarize himself with changes manu- facturer’s standards sizes, limits, gages, and keep both departments posted. This man should work for the material control depart- ment, acting consultant for that department, the engi- neering department and the purchase department. The importance standardization now well ac- cepted that little need said the subject. well remember, however, that standardization should start the engineering department. When suggestions along this line originate the control, the factory the purchase department, they changes. The principles kept mind are: Utilize standard shapes, sizes and limits for bulk stock. Use smallest possible variety standard purchase parts. Make fabricated parts used various mod- els and sizes products interchangeable, when- ever practicable. Confusion Regarding Parts Numbers fruitful subject for discussion found the assign- ment parts numbers. Parts numbers are used princi- pally because they eliminate the time and work required write out names and because they afford absolute means identification. the material control depart- ment, the importance this latter qualification enor- mous. The identification each part and assembly must absolute avoid confusion. Issuing parts numbers for new product comparatively simple matter. The difficulties arise when change made part for which number already has been assigned. There fairly widespread impression that when the new part and the old part are mechanically interchange- able new number necessary. This, however, apt the issuance engineering change when both parts have dealt with. This period continues until all old | parts are out existence, far production con- cerned. during this time that trouble occurs. illustrate, will assume that bronze casting has made harder. this end, the specification for bronze altered. All dimensions remain the same. the average eye, the outward appearance different. When completed, the new part and the old part will interchangeable, both mechanically and visually. Let assume, then, that new number issued. When the Old Number Continued After receiving the engineering change the mate- rial control department, the first consideration get into the material control records. this, the date when the new part into production determined and written notations are made the requirement record, the parts list and the stock record, which will indicate the specification change, date effective, etc. purchase requisition then made. this time there are usually purchase requisitions, purchase orders and invoices for the old part still extant, and correspon- dence between purchase department and vendors relative the old part still are necessary. This condition may continue for several weeks, with misunderstandings prac- tically certain ensue. due time the new parts begin arrive the plant and different receiving inspection methods are demanded. The new castings are practically indistinguishable from the old. Receiving clerks become confused. one feels sure what being handled. There doubt whether this the often recurring overshipment the old part, the first shipment the new. study invoices not always conclusive. More confusion fol- lows. When new machining methods are necessary the shop Aluminum-Silicon Alloys for Deoxidizing making killed steels common practice add both silicon and aluminum deoxidizers. The usual method addition use the silicon per cent fer- rosilicon and the aluminum stick aluminum thrown into the ladle shot aluminum fed into the molds. the Pittsburgh Experiment Station the United States Bu- reau Mines, Department Commerce, study being conducted, cooperation with the Carnegie Institute Technology and the metallurgical advisory board, deox- idation steel with aluminum-silicon alloys order find out the best method deoxidizing with aluminum and silicon. When there only small amount aluminum the alloy the inclusions formed are similar those formed deoxidation with silicon alone. the aluminum the alloy increases, the type inclusion changes from large glassy particle small particle which has some glassy characteristics but the main the amorphous type. These particles show high segregation the top small ingots and appear coagulate the steel much the same manner alumina. However, they segregate the ingot proper quite differently from alumina because the particles are somewhat larger than the alumina par- ticles. Even when the silicon content the alloy dropped per cent the inclusions still show considerable ten- dency coalesce. the deoxidation product can made coalesce somewhat, its chances being removed from the steel are much better than deoxidation products which remain colloidal suspension, the case deoxi- dation with aluminum alone. The ingots killed with these alloys showed extremely low iron oxide content. becomes involved and loss material and time ensues. The foregoing picture not exaggerated nor infre- quent. The same conditions are experienced when changes bulk stock, such steel sheets, bars, wire, are made. Almost all the trouble could avoided the assignment new number. The most satisfactory policy have found thus far is: Issue all part and assembly numbers through the engineering department. Issue bulk stock numbers through the ma- terial department. Issue new part number when one more the following characteristics change: Mechanical interchangeability. Material. change appearance which could confuse receiving clerks inspectors the rough, assembly department when finished. The above written advisedly, with full appreciation the added number blueprints kept file, and the extra work the drafting room, which, the way, frequently compensated for added certainty and less checking when new combinations parts are required. Absolute identification valuable the drafting room the material control department. summarizing the relationship the engineering de- partment material control, there are four things desired: Clear and comprehensive parts lists, logi- cally arranged. Engineering change notices which are ex- plicit and Generous use part and assembly num- bers. realization that time prime impor- tance effecting engineering changes and that, consequence, advance information frequently valuable. Delicate Tests for Chromium Compared HERE are rather delicate tests for chromium which are quite important many lines industry where chromium used. These have been compared Norman Stover, the University Alberta, Canada, Two tests which compared are the ether-hydrogen peroxide test and the test. found the latter much more sensitive than the former. Results the work were published the Journal the American Chemical Society, and brief abstract follows: When dichromate solution was acidified with sul- acid and shaken with ether, positive reaction for chromium (blue color the ether layer) was given little one part chromium 1,250,000. Portions the dichromate solution were acidified with certain acids, per cent acetic acid was then added. positive re- action for chromium was the production color min.; the color depended upon the amount dichromate present, being deep red with relatively large amounts and distinct violet with small amounts. The minimum amount chromium detected the diphenlycarbazide was one part 12,500,000 the presence acid, one part over 71,000,000 the presence acid, and one part 100,000,000 even 250,000,000 the presence sulphuric acid. When these tests were applied the usual course qualitative analysis, the minimum amount chromium detected was about one part 1,- 000,000 the presence acetic acid, while the ether- hydrogen peroxide test failed show the presence one part 250,000. The Age, May 1929-—1277 Problems Operating Gray Foundries Sand Control, Gating, Cupola Operations and Coke Tests Covered from Many . Angles—Unique Sessions Foundrymen Convention the features the annual convention the American Foundrymen’s Association the Stevens Hotel Chicago, April 11, was two courses gray iron foundry and steel foundry shop op- erations. They were held each afternoon the four days simultaneously four o’clock, and were presided over prominent foundrymen. Large attendance and keen interest the general discussion foundry topics char- acterized these meetings, and they were decided ‘success. AGE April 18, pages 1076 and 1077, was published brief report the sessions covering the steel foundry. the following paragraphs are pre- sented report the sessions gray iron shop opera- tion, well résumé the meeting sand control, which was held Tuesday evening, April This in- cluded with the account the shop operation courses because sand control was also the subject one those informal meetings. How Molds Should Gated molds was the subject introduced the opening session the gray iron course, presided over Harry Dietert. explained his method determining the cross-section the gate developed from various mold and castings’ section dimensions. The obtained answered perfectly for his line work radiators—where there are narrow ranges metal thickness and the sections uniform. Discussion brought out the fact that, for irregular sections, set formula would work out, and that only the experience and skill the foundryman could de- pended upon get satisfactory results. The subject strained molds, the cutting the sand, forced pour- ing, came duly, but the end the meeting settled down into giving experiences with internal shrinkages | ™ 1278—May 1929, The Iron Age castings related the position and size the gates and risers. would natural, the diversity opinion was large, Eugene Smith, Jr., Hougland Hardy Co., Evansville, Ind., holding that risers were not necessary, and foundry- men making heavy castings holding the reverse. pre- sented piece defective casting and lively debate re- sulted over the cause the trouble The blackboard was filled with sketches castings with internal shrinkages and suggested proper and improper gating, the position chills, the insertion nails and lumps cast iron cause faster setting, and other methods helping the difficulty. Dr. Moldenke explained the nature shrinkage for- mations, that was impossible normally feed mold slowly enough insure sound metal—the volume molten metal being reduced from per cent solidifying—and that therefore soundness any casting could not attained, though much could done miti- gate the difficulty artificial aids, causing the iron the thicker portions set fast the thinner ones. The advent lunchtime shut off the rambling debate, and would have been part wisdom have had classification the debatable points part the pro- gram, save time and get more definite facts for the large gathering attending this meeting. Fundamentals Sand Control AND control fundamentals was the main subject the second session the course, under the chairman- ship Major Bull. This was the most largely attended meeting the history the 750 members assembling the great ball room Hotel Stevens. Graham the Ohio Brass Co., Mansfield, Ohio, Foundrymen Who Participated the Sessions 7 q q 4 gave the first paper, describing the method handling and reconditioning the sand used his foundry. About tons supply the molders floors this system, and the turnover the sand hourly, that cooling and aeration are given particular attention. The line castings light, the actual average weight being 0.93 3-in. valve casting being the largest. About one ton new sand goes every day. The great number cores used makes the removal the prints serious problem. Otherwise the system the usual one conveying and re-tempering, with re-conveying the overhead bins sand-chutes the molders. Sand Control Malleable Foundry Ranis the Union Malleable Iron Co., East Mo- line, gave the next paper, sand control mal- leable foundry, where thorough sand testing used, but limited sand control exerted over only portion the molding floors. Where carefully controlled, sharp sand and clay are added either may required, and particular attention given the patterns, for was found that the lifting out patterns much damage can done the sand tearing away particles. This testing and even only partial control the sand heaps has resulted better work made and smaller losses castings. Here also the core-print question had watched carefully, otherwise the heaps would grow while los- ing strength the same time, necessitating rebonding clay addition. Further, the sand heaps would coarsen seriously, which meant rougher work. The cost this sand testing and supervision meant the addition one man the regular pay roll, caring for the work men the molding floor. The tests made were the usual American Foundrymen’s Association standards. Controlling Sand Gray Iron Foundry Requirements specifying for molding sands are different from those using these sands after they are received, said Harrington, Hunt-Speller Mfg. Co., Indian Orchard, Mass., for the character the sand quickly changed when the new mixed small quantity with the used material. Since sand free from clay, well clay for reviving the bond, are now generally used some quantity, special specifications for these are now needed. fact, great attention must paid the continued use clay for strengthening the bond, otherwise the scrap heap will soon show that this has been overdone. Effect sea-coal the sand also serious, acting like silting the sand with permeability troubles following. has been found that careful sand control actually fixes the number jolts within narrow limits making molds, and consequently very valuable its results. Finally, Mr. Harrington described the recent advances the American Foundrymen’s Association sand committee improving testing methods and ap- paratus, Reducing Number Bad Castings scrap was reviewed Eugene Smith. emphasized the importance permeability the sand used, and said most the troubles the foundry- men today hark back sand defects. his own shop practice, with exceptionally low losses castings— making valves and fittings—even here most these could traced back the sand and its abuse the molders. Further, the importance the bond was brought out, and what this means new sand where much the clay collected small balls which, worked into the heap, might give too much bond for good castings. Here the repeated use the sand for molds would gradually re- duce the strength the bond and restore the permeabil- ity again. Considerable discussion followed until ad- journment. Special Papers Sand Control evening session practice and development sand control, under the chairmanship Major Bull, was opened report the committee mold- ing sand research, presented Prof. Ries Cornell University, chairman the committee. described the general progress the work and indicated future developments. His report was followed the reports number sub-committees which the chairmen respectively gave the details such improvements existing methods sand testing had been made during the past year. They also outlined the tests directly ahead. These tests, and the specifications result therefrom, embraced the above-mentioned need for tests clays for reviving the bond molding sands, the testing core sands and the present status syn- thetic the discussion much attention was paid steel sands and the methods making this material, well purchasing the silica base and the binders. Harrington, chairman the sand reclama- tion committee, outlined the status results obtained number foundries, both re-bonding the sand used, making synthetic sand with the prepared old mate- rial, also with fresh material. The very considerable economies thus resulting were dwelt upon, and the fact pointed out that, the general inquiry made, but small percentage reports received proved unfavorable the idea bond improvement general proposition, though care would have exercised not overdoing the matter. After considerable further discussion details the inquiry the reclamation question, the floor was given Kurtz James Clow Sons, Chicago, read paper sound castings. Wilson the Jefferson-Union Co., Lockport, Y., his paper, “Some Experiments Sand Control,” discussed his suggested “hot permeability” test, having found that hot sand loses its permeability proportionally the temperature the sand subjected rises. was urged not overdo this, “red-hot” has particular interest the foundryman far permeability concerned. New Data Refractory Sands Canada, then gave paper the Foundry Sands,” which was great interest. gave much tabulation results fire-tests molding sands. Finally Harrington, reading paper for its absent author, sand-handling installations, and explaining some slides existing installations, closed the work the evening session, which adjourned 11.15, with those attending thoroughly exhausted. Cupola Control and Allied Topics third session the shop operation course, held Wednesday, was presided over MacKenzie, and was devoted cupola control and allied questions. program had been arranged which facilitated the or- derly progress the exchange information. Steel Scrap the Cupola David McLain took his subject the use steel scrap the cupola, telling his first tests this di- rection, with resulting practice per cent pig and per cent steel scrap. The discussion which followed went into the thickness section, whether laminated steel bundles could used, rails heavy head-sections, also the position the steel the charges the cupola. From in. in. thickness was considered best for the scrap sections, and putting the steel The Iron Age, May the coke, with pig and cast scrap top, was held the best method charging. Fluxes for the Cupola Cupola fluxes and raw materials formed the subject the next address, Evans the Mathieson Alkali Works, New York, the course which de- scribed how the coke burning covered with slag the ash contained. This prevents further rapid at- tack the oxygen the blast and, unless washed away very fluid fluxing reagent, will retard the melting operation. Limestone, over per cent calcium carbonates, this washing-off process, fluorspar thins the slag formed, and soda ash gives still more fluidity. Mr. Evans had found that best results are obtained when double dose limestone flux put right the bed coke the start. magnesium does After further discussion the merits manga- nese compounds for removing sulphur, the floor was given Lowry, consulting metallurgist, Detroit, who spoke pig irons general way. emphasized the unavoidable irregularities reduction the blast furnace, the size coke charged, the carbon absorp- tion, the best size pigs made and the consequent melt- ing points large and small pigs. ore Further Tests Coke Necessary Chairman MacKenzie then took the subject coke and pointed out the necessity further tests its quality, particularly the rate combustion, the tem- peratures which the different varieties will catch fire, the improvement cupola operations uniformly-sized pieces, and the possibility improving the quality the fuel the removal the soft ends. Petroleum coke, and its varieties different de- grees strength, came for much discussion, which also embraced the behavior steel when part the coke charges contained this very high-carbon fuel. The meet- ing was exceptionally well attended, and had the advan- tage that carefully divided program and selected speakers were arranged for the presentation sub- jects, thus giving the discussion more direction. Fuel Combustion the Cupola final session the shop operation course the close the convention was presided over Seullin, St. Louis Gas Coke Corporation, St. Louis. The fuel combustion question cupola melting was the first subject. was presented Vial, who went through the several phases the subject, giving the fundamental figures involved. asked that more at- tention given the waste gases the cupola, taken below the point which the air entering the charging door would affect them. recording system giving the percentages carbon dioxide, carbon monoxide, and pos- sibly free oxygen would indicate what was going down the melting zone, and provision could made charg- ing correct the height the bed—by putting extra coke, necessary, and slowing the blast until this extra coke would have reached the bed. Many points were touched upon the discussion, among them the relative heights different diameter cupolas, and the tuyere and cupola areas proportioned similarly. Gas Preferred for Lighting Cupola Work the session was completed the chairman his own preference being gas, instead wood oil; the absorption sulphur the slag and study the character the scurf found top machine cast pig iron. These are not all dangerous the foundryman may think, for the iron content per- fectly clean pig cast was found 92.5 per cent, whereas that same cast had badly scurfed pigs which the iron content was per cent—the scurf represented half per cent, and moreover contained 0.41 per cent calcium—or actually helped flux the impurity. Special Alloys Reduce Weight Battleships meeting the British Institution Naval Archi- tects held London, March 20, Sir William Berry read description the new battleships Nelson and Rod- ney. While these ships mount nine 16-in. guns, and carry- ing the unprecedented thickness 6%-in. deck armor against plunging shell and airplane bombs, they conform the Washington treaty requirement 35,000 tons max- imum standard displacement. “The problem weight reduction was attacked two directions—firstly, the general design the ship was disposed give the maximum effectiveness armor and armament within the smallest possible compass; sec- ondly, close attention the details structure, ma- chinery and fittings, eliminate all non-essential parts, and use the lightest materials appropriate the work. careful consideration all details (involving the re- design many standard fittings), and tightening the supervision manufacture, large measure suc- cess was achieved. One the most fruitful sources weight economy was found the employment ‘D’ qual- ity steel place the ‘H.T.’ quality formerly used the British Admiralty for the principal strength members the hulls heavy warships.* This steel has ultimate tensile strength from 83,000 96,500 lb. per sq. in., with minimum elastic limit 38,000 lb. per sq. in.; description the development this in a paper entitled “Steels for Shipbuilding,’ read by Sir Wil- liam Berry, before the Institution Civil Engineers’ Engineering Conference, 1928 (see THE IRON AGE, June 28, 1928, page 1813). steel was given 1929, The Iron Age about 6500 tons this steel was used the hull struc- ture each ship, and using higher stresses were accepted, with consequent reduction sections. The specified rolling limits were also amended insure that plates sections supplied should above the weight ordered. Extensive use was made aluminium and its alloys the manufacture minor fittings and such articles kit lockers. number different alloys were employed, some proprietary and some Admiralty specification, and experience far has shown that the main they have fulfilled their purpose. With further improvements design and material, these alloys should have very many useful applications for fittings not exposed the weather, nor subject very rough usage. For outboard fittings, which are exposed the corroding influences sea air and spray, the results have far been disappoint- ing, even though protected with paint, and evident that