The Iron Age 1945-12-06: Vol 156 Iss 23

J. H. VAN DEVENTER President and Editerial Director Cc. S. BAUR Vice-President & General Manager H. E. LEONARD Assistant General Marager B. H. HAYES Advertising Manager ©. L. JOHNSON, Manager Reader Service and Market Research R. E. BAUR, Production Manager R. E. CLEARY, Technical Research and Promotion Manager ° ° ° Executive Offices Chestnut and Séth Sts. Philadelphia 39, Pa., U.S.A. Editorial and Advertising Offices 100 East 42nd St., New York 17, N.Y., U.S.A. ° ° ° Regional Business Managers C. H. OBER H. E. LEONARD New Yerk 17 New York 17 OnE 42nd St. 100 East 42nd St. ROB Oe i R. M. —_— - ae Bidg. 428 Park Bi B.L. a H. ra HOTTENSTEIN Philadelphia 39 a cago 3 Chilton oe 34 Otis BI PEIRCE LEWIS 0. - WARREN Detroit 2 Hartford |, Conn. 7310 Woodward Ave. P. O, Box 8! R. RAYMOND KAY Los Angeles 28 2420 Cheremoya Ave. ° ° ° Owned and Published by CHILTON COMPANY (Incorporated) OFFICERS AND DIRECTORS Cc. A. MUSSELMAN, Chairmen JOS. S. HILDRETH, President | GEORGE H. GRIFFITHS Vice-President EVERIT 8B. TERHUNE Vice-President J. H. VAN DEVENTER Vice-President C. S. BAUR Vice-President P. M. FAHRENDORF Vice-President JULIAN CHASE Vice-President WILLIAM A. BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary 6. C. BUZBY HARRY V. DUFFY THOMAS L. KANE CHARLES J. HEALE ° ° ° WILLIAM H. VALLAR, Asst. Treas. tC) ° Chilton Editorial Board PAUL WOOTON Washington Representative ° ° ° Member, Audit Bureau of Circulation Member, Associated Business Papers Indexed In i § Industrial Arts Index. Pub- noe every Th Subscription Price | pon Seaton, "America and U. S. | Tone ngh se Pape Sine, Renee Noten New umber $2 | ° ° Cable ani “lronage”" N. Y. ° ° ° Copyright, 1946, by Chilton Company ( Ine.) Thie Weele in The Vol. 156, No. 23 December 6, 1945 Editorial The Four Horned Dilemma ° ° ° Technical Articles Heat Treating Beryllium Copper Emergency Gas Welding of Magnesium Parts Heat Treating, Forming & Welding 75S Alclad Metallic Impurities in Steel Effect of Work Position in Face Milling Color Merchandising of Metal Products Emergency Gas Welding of Magnesium Parts New Equipment Features Newsfront Assembly Line Washington West Coast European Letter Personals and Obituaries Dear Editor This Industrial Week News of Industry News and Markets Machine Tool Developments Nonferrous Market News and Prices Iron and Steel Scrap News and Prices Comparison of Prices by Week and Year Finished and Semi Steel Prices Alloy Steel Prices... .. Fabricated Steel Products Prices. Warehouse Steel and ~~ Iron Prices Ferroalloy Prices . New Construction Labor Advisory Groups Held by CPA Allocates Surplus Metals Small Business Must Plan for Re-employment. RFC Offers Plants Taft Proposes Price Rise to Offset Costs Wage Rates for Pullman Employees British Veteran Skids to Bottom Production of Farm Equipment Declines India’s Iron and Steel Trade Declines Congressional Action on Employment Proposed Spurns Back Seat Driver. . Chinese Technical Men Visit U. Ss. Canada’s Reconversion Includes New Products Atom Bomb for Domestic Use Management Assn. Plans for Packaging Canadian Aluminum Drops Carte Investigate Im Disposals of Goods Use of 20 Mion Vole B Betatron Index to Advertisers 55 58 65 71 72 77 81 124 126-27 128-29 130 132 133 134 135 136 138 144 146 148 152 156 158 459 159 160 162 164 166 167 168 169 170 170 172 172 273-74 | : ; | . teel Products Fabricators of Welded Steel Machine Bases, Frames, and Many Other Welded S$ 54—THE IRON AGE, December 6, 1945 IRow AGE The Four-Horned Dilemma DILEMMA, according to Webster, is “a state of things in which ie eae evils or obstacles present themselves on every side and it is diffi- en ae Ordinary i giving the victim an alternative Coes: 6.99 | which is just as likely to impale him on its horn. But the ordi two- ad dilemma is a “sissy” compared with the present controversy | between management and labor. This indeed is a four-horned creature J. H. VAN DEVENTER which threatens to gore not only the two principals, but government eee. ct and the public also. C. S. BAUR In earlier times, before the concentration of productive capacity and Oe of labor power had developed, a strike or a lockout confined its effects to the comparatively small groups involved and that minor portion of the public in the immediate locality which might suffer from loss of Ean i ace 413 ea ORT trade or service. But when the scale Se caantiee that of : “te toda ee perenanee y ughout the country, we ERE eer | the cenetion emerges from that of a private controversy and becomes a public problem. The man in the street, I think, knows what the labor part of the problem is, since it has been given plenty of publicity. He also has some insight to government’s present dilemma in choosing between political advantages and constructive economic principles. As for his own dilemma, which is a one-sided one, he sees the hoped-for-prosperity which would bring him a new car or a home or a thousand other wanted things retreating into the distant future if not dissolving altogether. But management’s dilemma, not having been particularly well publi- SCHIMKO cized and being somewhat remote from him is not clearly seen or j realized. ee aes Management’s dilemma is not the wage question, primarily, although Grene JACK R. HIGHT | that indeed is a part of it. Its big problem is that of facing an uncer- Canada (Contrib.)...F. SANDERSON tain future with sufficient ial functions left to exercise to enable Regional News and Technical Editors it to survive. T. & LLOYD This statement is no exaggeration. For the past 15 years, there has am Port Bide been a progressive emasculation of the power of management to manage. et ret It has reached a point where industrial discipline no longer exists in Chicago 3 many unionized plants and factories and where flagrant infractions of ay ee ee ordinary decent rules of business conduct are immune from managerial L. W. MOFFETT action. 0 9 ANSBORO. Today and for several years past, an unruly or incompetent worker wore de can literally “thumb his nose” at plant authority provided he holds a union card. Management is asked to bargain with a group that though hoe particularly one-sided, through political class legislation, is immune from 1016 Guardian Bldg. the laws which govern all other citizens; that has shown its inability to S. H. BRAMS discipline its membership and its utter disregard for contractual obliga- 7310 Woodward. Ave. tions. Ss P cuenta: tumanex Not only through political maneuvering has management been com- WORTH HALE | pelled to enforce reluctant union membership through check-off, but in oo, one 3 addition it is now facing the amputation of its right arm of foremanship. : And to cap the climax, it is now faced with the demand that it, unlike “aioe the unions, shall open its books to determine wages, which is as logical Cincinnati as the demand of a prospective cook to examine her prospective em- L. C. DEAN ployer’s income tax statement. Buffalo I do not think that American industrial management is reactionary, but it wants fair play, honest rules and an unbiased umpire. Assure it of that and the present controversy, so costly to all of us, will be over. ' vs ens oa ti GD am adie amiear - nth ae re 4 eee eA . CP: 4 g . ine oe! 2 hn ln i pager sty pt A SITS : nal . ‘ ? ss nner > OA BILE ELIT SD per. ee oan | weer tablg sey x ~ abst tier eM BET Ss“ 23 eo eo, G, FRAZAR Boston HUGH SHARP Milwaukee R. RAYMOND KAY Los Angeles JOHN C. McCUNE Birmingham : St. Louis JAMES DOUGLAS Seattle a as mang ee ngnnrctemninta cenit >I a eee STREAMLINING In these days of transition many manufacturers are going into the prodiiction of radically new products, becoming familiar with new equipment, adapting old machines to new uses and finding out how to coatiol processes that are different. They are in the throes of a “swing-back” from wartime operation to peace- time manufacturing. Inland metallurgists are familiar figures in many of these plants, where for years they have been apply- ing their expert knowledge of putting steel to work for others. Today, Inland metallurgists are continuing that valuable work. Their technical and practical experi- $ ‘* 22 I > 5 aS ~ : ; ‘ : . - . > , ° . * at «| Be ate Sea a | bo r a ‘ 7 e ss “ 4 z pe ; ; : : , — ; . tine i . Seat ; - — ' ‘ a — a wi PO en cae “SWING-BACK™ ence in the selection of steel, in latest fabrication methods, and in speeding up output, are helping manu- facturers produce many kinds of newer and better products. If you have a problem in the use of steel, call on us. A member of our metallurgical staff will be glad to call and work closely with you. Inland Steel Company, 38 S. Dearborn St., Chicago 3, Ill. Sales Offices: Cincinnati, Detroit, Indianapolis, Kansas City, Milwaukee, New York, St. Louis, St. Paul. Principal Products: Bars @ Structurals @ Plates Sheets ©@ Strip ©@ Tin Plate © Floor Plate Piling @ Reinforcing Bars @ Rails © Track Accessories = ~ NEWSFRONT i200 ACE Dec. 4, 1945 e A new type of attrition grinder is under development on the West Coast, smaller than the conventional ball mill, which is said to reduce ore—in-process to | a much finer grind. ® The Kaiser Co. has now repaid four years in advance the $28.5 million RFC loan on the Permanente Metals magnesium plant at Los Altos, Calif., plus an additional $3.5 million in interest. Metallurgists at the plant are working toward cost reduction, having completed § this work up to the powder stage at the furnace. It is estimated that cost figures have already dropped by a third and may reach 50 pct when complete. pm Hardening of beryllium copper compounds during heat treating develops during atomic rearrangement preparatory to actual precipitation, recent work with the glectron microscope indicates. Precipitation of the gamma phase, which heretofore was considered responsible for the hardening properties of beryllium copper, does not occur until peak hard- ness is passed and softening of the alloy begins. pm Extruded shapes or bars of 75ST Alclad have frequently shown physical proper— ties in excess of those of normalized 4150 steel. Ultimate tensile strengths up to 95,000 psi and yield strengths of over 80,000 psi have been obtained. e Probable frequency of emergency landings or "ditchings" on New York-—London flights currently are estimated in the neighborhood of one per 16,576 flights. Qn Army Air Forces operations during the war with B-29 Superfortresses, including combat flying, the record was only one ditching for each 750,000 miles of flying. > Aluminum surface finishes, such as Alumilite and Alrok, are being made avail— | able to finishing shops on a very nominal royalty basis. Although Alcoa's royalty charges have never been high, this practice is expected to encourage the use of luminun. France is rebuilding her merchant marine by placing large orders abroad, prin- | ipally in Britain whose yards now have 1} yr. backlogs. Likewise Scandinavian yards are tied up, and there is some possibility that some French orders for ves- sels may find their way here. >» Details of the only factory built completely underground in Britain during the war indicate that it was built in a thickly wooded hill face in a chalk escarpment. According to reports the construction costs were about the same as those for average type surface construction, and the time of construction tion about the same. All other underground factories were developed from quarries, caves, or other excavations. etter > With minor adjustments 500 armored cars are being sold in South Africa to ease that country's tractor shortage. Following extensive tests by the country's department of agriculture, it was announced that fuel consumption is no higher n us. than that of the ordinary tractor. lad » UNRRA is starting a comprehensive rebuilding program for Europe's transport 6 system, including orders for thousands of railway cars from U. S. and British tanufacturers, and acquisition of excess Army supplies of bridge building ma- ‘trials, railway track materials, and some locomotives. For the maintenance of American trucks being furnished to Poland, the relief volis, agency is purchasing the repair depot at Gloucestershire, England, which has been Paul sed throughout the war as the main base for automotive repairs. According to reports the British Board of Trade is asking its industries to ‘lates prepare lists of German plants which they would like to have moved to England. Plate he inference is that the lists should not be restricted to plants which are more mdern than British counterparts, as if they are not moved to Britain, they will probably go somewhere else. The general feeling in the steel industry, however, remains steadfast in the pinion that with the exception of the probable removal of a single plant to titain for study, there will be no transferral of German steel capacity to ritain. Mi anu- cago ories i fi a oe ei ert 129 ee .% Pe iy q i iy syne ine, - ~* a Ficy ‘ ae ea Cb ne EN “ 1 cette ean Heat Treating Beryllium Copper For Peak Performance . - - Heat treating to a hardness specification is no assurance that co beryllium copper part will deliver the performance desired. Selection of the one best heat treatment requires: (1) Full knowl- edge of the way the part is used, (2) heat treating response data on the lot of material to be used, and (3) testing of finished parts to make certain they perform as desired. While primarily con- cerned with springs, the technique described here applies as well to any part made from strip or wire. By H. G. WILLIAMS Chief Metallurgist, Instrument Specialties Co., Inc., Little Falls, N. J. ° ° ° user of springs and stampings a unique combination of prop- erties. A tensile strength of 200,000 psi places beryllium copper in the steel class, yet it is corrosion resis- tant, nonmagnetic, and conducts elec- tricity four to five times as well as steel. (Of current interest, this copper Be we ot ve copper offers the alloy uses no tin and is readily avail- able.) It has higher endurance strength, greater conductivity, and can be used at higher ambient tem- peratures than any other copper alloy. Beryllium copper gains its excep- tional properties largely through heat treatment, making possible the form- TABLE | Physical Properties of Beryllium Copper = | ANNEALED After Before Heat Heat Heat Heat Before Heat 2 3 4 1 | 6 FULL-HARD HALF-HARD After Before Temper Treating | Treating | Treating | Treating | Treating | Treating Tensile strength, psi 70,000 Hardness, Brinell, 3000 kg 10 mm ball. 15 | 165,000 ’ , 155,000 | 215,000 Elastic modulus, x10® Electrical conductivity, pet ACS... 58—THE IRON AGE, December 6, 1945 ing of intricate shapes while soft and ductile and then hardening to spring temper with a low temperature heat treatment. The same hardening heat treatment also can be used to free the structure of internal stresses, result- ing in greater stability than found in spring alloys that gain their temper from cold work. In addition, this stress relieving heat treatment makes possible heat-treat forming of parts to closer dimensional tolerances at low cost. It is this combination of desirable properties that leads to the wide use of beryllium copper, yet each indi- vidual application seldom requires all of the properties to an equal degree. A precision coil spring in an instrv- ment needs close dimensional control for accurate calibration and extreme stability to maintain calibration, but does not call for high endurance strength or electrical conductivity. A flexible electrical connector will need good electrical conductivity and high endurance strength, but stability and dimensional control are relatively un- important. Some of the useful properties of beryllium copper are inherent in the composition, but most are gained by the hardening heat treatment. The rate at which these properties develop during hardening varies with heat- treating time, thus offering an oppor- tunity to select the time and tempera- ture which will enhance the particu- lar characteristics desired. Complete analysis of how the part is to func- tion and recognition of just what is required of the part makes possible a heat treatment giving higher and more consistent performance. If only one characteristic is in- volved, the selection of the proper heat treatment is relatively ©asy- More often several properties 4ré wanted, some two of which may not ordinarily develop to the greatest de- ~nee eoeseweteaat oe gree at a single heat treatment. The 230 proper alloy composition, the amount No.| of cold work prior to heat treatment, Tensile strength | the solution anneal before the cold 210 ; work, and the temperature used for the heat treatment are all factors bearing on the relative rate at which the various properties develop. To ob- tain full advantage of what beryllium copper offers requires complete knowl- 170 edge of the effects of these factors. Effect of composition and metallur- ° ° ° gical defects upon the hardening re- a 20 sponse of beryllium copper has ; already been discussed.-* For any RIGHT specific spring application, service F ames a life, cost and performance will be hard beryllium-cop- affected considerably by the heat- per during heat 1000 psi Copper, pct treatin treatment at 660° F. 16 0.005 g time and temperature, and ° to a lesser degree by the effect of S oft and temper and solution anneal upon the ee ° 0003 & spring useful properties of beryllium copper. oS re heat The beryllium-copper alloy most = g heat commonly used for spring applica- 10 0.001 & ree the tions is covered by ASTM Specifica- S result- tion B120 which includes a composi- . und in tion range of 1.90 to 2.20 pct 5 5 temper beryllium, 0.5 max pet of nickel or & a, vm cobalt, 0.5 max pet total impurities, = Se and balance of copper. This alloy is w 0 Se ae solution annealed by heating to 1400° to 1475°F and then quenching rap- sirable ide use h indi- " No.1 No.2 No3 .. ires all Tensile strength | 0 5 i) 15 20 25 30 degree. 170 Lady Heat-treating time, min. instru- =! TA xtreme a.150 0 idly. Control of the time and tem- on, but S fae = perature of the anneal and the rate jurance = 130 5 of the quench affects the grain size “a es and the amount of beryllium available for hardening. Typical properties of beryllium copper in the annealed ir &- ee state are shown in col. 1 of table 1 Accurate control of the annealing op- 9 + dt age b eration is necessary as the solution we Sei "+ + Set ts ned by 6 a 007 puts the beryllium into solution with J - aaa ; Sevelo 1 co iS. 2—Pr precipitation hardening process which elop °5 BG ye oe | eee mS aa of yo follows. The final properties obtain- 8 Copper, pct x 10 : nealed beryllium able depend upon the amount of eee 20 0003 8 © ceed ee beryllium in solution and available varticu cs for hardening. ymplete S Ductility | o Beryllium copper may be formed in > func c IS ‘001 ae ee this state or it may be cold worked to what 1s = a higher temper before forming, de- vossible S19 pending upon the severity of the er and S forming operation to be used. Since f " cold work generally enhances the final a 5 spring properties, it is usual practice proper to use as high a temper as can readily =. 0 stand the forming process. Col. 3 of ow Gt ae oa De ae table 1 gives the physical properties a “ Heat-treating time, min. of half-hard temper, and col. 5 of THE IRON AGE, December 6, 1945—59 table 1 shows the corresponding prop- erties of full-hard temper. These values are representative, not mini- mum specifications nor the maximum obtainable. Hardening heat treatment is usu- ally given after the part is formed and consists of heating between 550° to 750°F for times ranging from sev- eral hours to a few minutes. The mechanism involved is commonly re- ferred to as precipitation hardening, wherein the unstable supersaturated beryllium copper solid solution is de- composed by the heat treatment to form a gamma phase precipitate that increases the slip-resistance of the crystals. The precipitated particles have been considered submicroscopic in size, but recent work with the elec- tron microscope indicates that the hardening develops during atomic re- arrangement preparatory to actual precipitation.‘ Predicting Spring Performance of Beryllium Copper Wire and Strip,” by H. G. Williams, Tue Iron Ace, July 8, 1943, pp. 62-67. Heat-treating Beryllium Copper,” by Wayne Martin, THe Iron Ace, Feb. 24, 1944, pp. 66-71. “Available Beryllium in Copper,” by H. G. Williams, Metal Progress, July 1944, pp. 79-81. “A Study of Age-Hardening Using the Electron Microscope and Formvar Rep- licas,” by D. Harker and M. J. Murphy, Metals Technology, June 1945, vol. 12, No. 4. A problem in nomenclature is here presented if the hardening is due to an ordering rather than a precipita- tion, although if the time at heat- treating temperature is long enough, a definite precipitation does occur &0—THE IRON AGE, December 6, 1945 LEFT F Is. 3—Solenoid quides of beryllium copper have ten times the life of any other nonmagnetic material when heat treated for maximum abrasion resistance. BELOW F Is. 4—Beryllium - copper brush springs heat treated for minimum drift hold brush tension at temperatures 100° F higher than bronze springs will stand. with formation of discrete gamma phase particles. However, this point is not reached until peak hardness is passed and a softening of the alloy occurs. The process is sometimes called “age hardening” due to its similarity to the aging of aluminum alloys which were initially stored at room temperature to develop improved properties. This notation has some advantages since it is a process in which time is important although higher temperatures must be used. It allows the use of the term “overag- ing” for heat treatment in excess of that needed to develop peak hardness, and “underaging” for heat treatment insufficient to gain peak hardness. It is more commonly called the “hardening heat-treatment” since the change in hardness upon heat treat- ment is the most easily measured and the most evident property change. It is not the only change, however, and in many cases not the most important, as shown in cols. 2, 4 and 6 of table 1. When beryllium copper is heated, hardness increases with heat-treating time until a peak is reached and then the hardness drops off as the treat- ment continues. Tensile strength and elastic limit curves parallel the hard- ness curve. Ductility decreases with heat-treating time, reaching a mini- mum at the point of peak hardness and then increasing again as the alloy is overaged. Electrical conductivity increases fairly rapidly to 25 pct of copper at peak hardness and then slowly increases as the alloy overages. Elastic modulus shows a pronounced increase which levels off at about peak hardness and remains constant with continued heat treatment. Stability of the alloy (its ability to resist drift or loss of spring pressure under load with time) is a function of two properties, the elastic limit, and freedom from internal stress. Stabil- ity, therefore, increases with heat- treating time until maximum elastic limit is reached, there attaining peak stability if stress relief is complete. If stress relief is not complete at peak elastic limit, stability continues to in- crease with additional heat treatment until the gain from more thorough stress relief is counter balanced by the loss in elastic limit and the sta- bility then drops off. Many Factors Affect Endurance Because many factors affect the en- durance limit of a part, it is difficult to isolate the effect of heat tfeatment alone, but in general, peak endurance -_ —m& aes: mw UwmlCCeOlUmelUlUe lee then Teat- 1 and hard- with mini- dness alloy tivity ct of then ages. inced about stant ity to ssure on of , and tabil- heat- lastic peak te. If peak to in- tment rough ed by 2 sta- he en- ficult tment is found with peak tensile strength. The work done on shot blasting has indicated the value of residual sur- face stresses in enhancing endurance life. The retention of surface com- pressive stresses from cold work by underaging has shown some favorable results, making the peak endurance strength somewhat precede the peak tensile strength. In many practical applications the deflection of the spring is one of fixed degree of move- ment rather than of load, and in this case underaging, with its consequent lower modulus, results in lower stress thus making peak endurance appear to be at a point below peak tensile strength. Relationship between the properties developed and the heat-treating time is shown in fig. 1, for half-hard temper, heat treated at 660°F. Indi- cated on the chart are three of the possible heat treatments which can be used for this material. Point of peak hardness, No. 1, is used for maximum wear resistance and high endurance life. Heat treatment that gives mini- mum drift, No. 2, is used for any spring where its ability to maintain calibration or to hold its pressure during life is of importance. No. 3 is the time that would be selected when additional electrical conductivity is desired or when additional ductility is needed and some sacrifice of other properties is permissible. Similar curves for annealed stock at the same heat-treating tempera- ture are given in fig. 2 with the equiv- alent heat treatments indicated. Note that annealed stock is preferred to half-hard temper where greater duc- tility is desired, but not where maxi- mum hardness or lowest drift is nec- essary. Note also that the point of minimum drift is further from peak hardness than for half-hard temper material. Because of its slow rate of stress relief, annealed material takes a longer time at temperature to be- come free from residual internal stress. Rate of stress relief is important from another practical angle—the use of heat-treat forming as a fabricat- ing process. Since the hardening heat treatment can be done at a tempera- ture high enough to give considerable F 1G. 6—Progressive steps in the production of a beryllium-copper instrument frame. Heat treated for best conformity this part is stronger, lower in cost and lighter weight than an equivalent diecasting. stress relief, it is possible to form many parts by clamping them to the desired final shape in forming fix- tures in which the parts are then heated. After a stress relieving heat treatment the parts will then main- tain the form in which they were held. This procedure is used to man- ufacture many simple parts and is also used to develop a high degree of dimensional accuracy in otherwise nonuniform punch-press parts.’ It eliminates many of the springback problems in forming, and _ gives greater precision than can be attained by conventional methods. The accu- racy achieved depends on the degree of conformity to the fixture, which in turn depends on the thoroughness of the stress relief. Heat treatment No. 8 can be used to gain more conformity when dimensional control is of greater importance than peak hardness or low drift. Many parts requiring close dimen- sional control also require low drift, so it is desirable to obtain a high de- gree of fixture conformity with good spring properties. Some gain can be made by using more cold work prior to heat treatment. Increasing cold work increases the rate of stress re- lief more than it increases the rate of hardness response, so in severely cold- worked material a No. 8 heat treat- ment moves closer to peak hardness giving better spring properties with the same degree of stress relief. But there is a limit to what can be gained by this method; and the forming of an intricate part may prohibit the use of higher temper stock. The best heat treatment may then require using a different temperature. At 550°F it takes 5 to 8 hr to bring half-hard beryllium copper to its peak hardness. At 600°F the time is 1.5 to 2 hr, at 650°F it takes about 20 min (as shown in fig. 1), and at 700° F peak hardness will be reached in about 12 min. At 750°F the time is about 5 min, but the hardness reached is not as high as at the lower tem- peratures, and in addition the time is too short to be readily controlled. If the major requirement is high hardness for wear resistance as in FIs: 5—Specially designed automatic machine for coiling beryllium-cop- per wire directly on the heat treating fixture makes possible high pro- a0)" duction of close tolerance, low-drift springs. ng “e Longin ans = = et eo ee ee TN ee eS saisiore ay ot ~— ee eee ee Te EPS ABOVE IG. 7—Precise measurements of drift on the Carson Electronic Mi- crometer provide the heat treatment control required to obtain maximum stability in beryllium-copper springs. bearing applications, or high tensile strength and yield strength and yield point for structural parts such as air- craft door hinges, any of these tem- peratures can be used with the corre- sponding heat-treating time. The use of 600°F with a time of 1 to 2 hr re- quires less critical control of time and temperature and is more practical for the shop not well equipped with con- trol apparatus and trained personnel. Parts of heavy cross-section are also best hardened at the lower tem- peratures to gain uniform hardening throughout the piece. This applies to beryllium copper hammers, chisels and other parts used as sparkless tools. In some forms of heavy cross- section it is desirable to have maxi- mum surface hardness for wear re- sistance, but brittleness is detrimen- tal. Here a high hardening tempera- ture can be used to give a case-hard- ening effect with the surface at peak hardness and the core underaged with consequent greater ductility. In making high-quality § springs much advantage can be derived by using carefully controlled higher hardening temperatures. As the heat- treating temperature is increased, the rate of stress relief increases so that at the higher temperatures, around 700°F, the point of minimum drift theat treatment No. 2) closely ap- proximates peak tensile strength (heat treatment No. 1). Since the 62—THE IRON AGE, December 6, 1945 same degree of stress relief can be attained at a higher elastic limit, the amount of drift is lower, resulting in a spring of much greater stability. Small improvements in drift are of considerable significance when the nature of the drift phenomena is un- derstood.® The increase in deflection of a spring under constant load pro- ceeds logarithmically with time. Drift of 0.001 in. in 1000 hr will be followed by drift of an additional 0.001 in. in the next 10,000 hr. Reversing this conception, if in a calibrated instru- ment the spring shows enough drift in one year to impair its accuracy, a 50 pct reduction in drift rate in- creases the useful life by 10 times. The significance of drift is not con- fined to finely calibrated instrument springs alone, but it can determine whether such a crude article as a screen door spring gives out in a month or lasts for a couple of seasons. Increasing the relative rate of stréss relief compared to the rate of hardening by using higher tempera- tures also increases the degree of conformity when dimensions are be- ing controlled by fixture heat treat- ment. Thus, close dimensional control can be combined with high spring properties. For parts where dimen- sional accuracy is more important than maximum spring qualities, tem- peratures well above 700°F may be required. One word of caution regarding the curves and the heat-treating times given here: These values are relative and cannot be used as specific recom- mendations: Heat-treat response curves must be developed for each lot of material used if consistent results are to be expected.’ * Various Practical Applications Some practical applications of these heat-treating principles to typical beryllium copper parts are shown in ss oe: the accompanying illustrations. Solenoid guides, fig. 3, require a nonmagnetic material with high wear resistance to file-like abrasion of a laminated core that rides in the un- lubricated guide. For one of the parts shown, the best material previ- ously used failed after 200,000 cycles of operation whereas no failure has been reported after 3,000,000 cycles with the beryllium-copper part. An- nealed stock is usually needed to stand sharp bends during forming. These guides are hardened to peak hardness (heat treatment No. 1) to gain maximum wear resistance. To maintain close tolerances so that the plunger can move freely yet be ac- curately guided, heat-treating fixtures are used to hold essential dimensions. Under these conditions a heat-treat- ing temperature of 700°F gives maxi mum fixture conformity while retain- ing high hardness. For brush springs used in frac- tional horsepower electric motors, fig. 4, beryllium copper has an almost ideal combination of properties. It offers both high strength and low modulus which makes possible a ‘eat- itrol nen- tant y be ' the imes ative com- nse h lot sults these pica] m in re a wear of a > un- the revi- rycles > has ycles An- d to ming. peak l) to To t the e ac- tures sions. rreat- maxi- stain- frac- otors, Imost | low le a spring design that will deliver the necessary pressure in a confined space and yet have a low deflection rate so “Making Beryllium Copper Behave,” by R. W. Carson, Metals and Alloys, Dec. 1943, pp. 134-139. “Stability of Some Alloys for Springs,” by L. L. Stott and R. W. Carson, Metals and Alloys, Sept. 1938. “How to Design Brush Springs for Long Brush Life,’ by R. W. Carson, Electrical Manufacturing, Sept. 1942. the pressure will not be lost as the brush wears.’ The springs must be produced to an accurate load test as correct pressure is essential to good brush life. Control of coil diameter is important so the spring will properly fit the brush neck. Good thermal con- ductivity prevents local heating of the spring, and the high electrical con- ductivity of beryllium copper often makes possible the elimination of the shunt used to carry the current from the brush, offering a chance to reduce motor costs. To make these highly accurate springs at low cost, specially designed high-speed machines, fig. 5, wind the springs on the mandrels on which the springs are heat treated. They are given heat treatment No. 2 for mini- mum drift at a high temperature to gain accurate dimensional control. The electrical instrument frame, shown in fig. 6, is typical of a wide field of use for beryllium copper, in this case successfully supplanting a diecast part. Accurate alignment and the elimination of finish .machining enables it to compete on a cost basis it even lower production quantities. Most of the diecast alloys are of com- paratively low strength, and beryl- llum copper gives greater rigidity with thinner cross-sections, saving space and weight. Annéaled stock is used for this part because of the in- triceate forming, with a No. 3 heat treatment at high temperature. This heat treatment develops high dimen- sional accuracy at some sacrifice in maximum hardness not needed for the application. The spring shown under test in the Carson Electronic Micrometer in fig. 7 is an example of a real precision coil spring. It is used in an aircraft engine carburetor where high stabil- ity is very important. This spring must meet a load test of +2 pct, and the drift during its life must be less than 0.002 in. to avoid affecting the operation of the carburetor. This spring is wound and heat treated on a mandrel. Heat treatment No. 2 for minimum drift is used at the highest possible temperature to gain close control over dimensions. To develop maximum properties at the high tem- perature, full hard wire is specified with a minimum tensile strength of 215,000 psi after heat treatment. Al- LEFT IS. 8—Each one of these flat springs delivers the best avail- able beryllium-copper perform- ance needed for the job by se- lecting the heat treatment to en- hance maximum endurance, mini- mum drift or maximum = stress relief. BELOW IG. 9—A high - temperature heat- treatment delivering maxi- mum stress relief in combination with fixture forming produced these beryllium-copper parts un- obtainable by conventional meth- ods. though a precision spring, it has been produced in quantities of over 100,000. Relays and switches in telephone, radio and communication equipment use many formed flat spring leaves such as illustrated in fig. 8. Here beryllium copper is selected because of its corrosion resistance, high elec- trical conductivity, and its ability to maintain uniform pressure during the life of the part. It has long been common practice to assemble these switches and individually adjust the pressure of each leaf by manually bending the springs. Springs so bent are not stable and gradually relax from position throwing off the contact adjustment. This contact adjusting operation is also one of the most costly elements of the assembly as it must be done by hand and requires much inspection. But beryllium-cop- per blades can be so accurately formed as to eliminate this step, in many cases saving several times the cost of the springs. There is the fur- ther assurance that a relay removed from storage many months after as- sembly will still retain its initial ad- justment since there would be no re- laxation of bent leaves. Flat springs of this type are stamped from half-hard to full-hard stock and hardened by heat treatment No. 2 or No. 3 depending upon whether the emphasis is on maximum THE IRON AGE, December 6, 1945—63 ta 1: , PY + - 3 btm iy ‘ : a4 Bo rf J SOP A, TE ae, Be TWO SEY eet eee es es he or i \ wep oN tae a" ite asi thine 2 a Beat ree cea a aera wc " o Fea? (Oe bi een eh ght %K) BAS Beta NY tte * sR i» paw s ON eee Ler Se ; ne ayy, caps eee i a a ees be Rg i spring quality or control of aimen- sions. High-temperature heat treat- ment is used to gain maximum dimen- sional control consistent with high spring properties. In many cases the forming of the part is done entirely by the heat treatment, saving the cost of a forming die. Parts shown in fig. 9 are typical of a variety of designs that can be made from beryllium copper using heat- treating fixtures as the sole forming tool. This makes possible the manu- facture of many forms from thin stock that would not otherwise be practical. Here again high-tempera- ture heat treatments are used to gain rapid stress relief. The heat-treating time may vary from No. 1 for high endurance, when accurate forming is not the critical factor, to No. 3 when the emphasis is upon dimensional control. In these examples emphasis has been placed on heat treating for the performance desired. This is not heat treating to meet some minimum hard- ness specification which may not be the significant factor in the operation of the part. To select the best heat treatment requires full knowledge of the conditions governing the use of the part, and then testing of finished parts to make certain that they per- form as expected. When a spring is needed to deliver a certain pressure and to maintain that pressure for a definite life, it is more direct to fur- nish a load tested spring with a known drift rate than to supply a spring that has certain dimensions and a hardness reading which indi- cates that the spring would probably perform as desired. The indirect ap- proach is particularly misleading when applied to spring parts made from annealed stock. Annealed stock is usually selected only when intricate forming or draw- ing is needed. Maximum working stresses are usually in the formed portion of the part, where the mate- rial receives considerable cold work. But the unworked flat portion is the only section that offers a chance of testing.for hardness. Any heat treat- ment giving maximum hardness on such a flat section will be sufficiently long to cause overaging of the cold worked portion of the spring because of the effect of cold work on the rate of hardening. Therefore, if the spring is merely heat treated for maximum hardness, it will not perform as well as if it were heat treated for mini- mum drift as measured by a perform- ance test using the Electronic Mi- crometer.® This direct measurement of spring performance as a guide to se- lecting heat-treating conditions makes it possible for beryllium copper to deliver much more of the exceptional performance available in the alloy. Tin Undercoats for Painted Steels Improves Corrosion Resistance N the course of investigations on the electrodeposition of tin on steel undertaken by the Tin Research Institute, it was noticed that tin coatings as thin as 0.000008 in. were remarkably effective in preventing the rusting of steel sheet in the indoor at- mosphere and had a considerable re- tarding influence on rusting outdoors. Since these coatings were only one tenth of the thickness of tin ordi- narily applied to tinplate of canning quality and less than one hundredth of that applied to hot-tinned steel ar- ticles such as dairy equipment, it did not seem reasonable to the investiga- tors to expect useful service from such thin tin coatings alone. It ap- peared worthwhile, however, to exam- ine the extent to which they influence the protection afforded by the subse- quent application of paint coatings. This study, reported to the British Iron & Steel Institute by Dr. Ernest S. Hedges and Dr. L. A. Jordan, cov- ered electrodeposits of tin from both the alkaline and acid tin baths, using* thicknesses of 0.000008 in. and 0.00003 in., the effect of flash melting the tin coatings and of oxidizing the tin sur- face by chemical treatments. In ad- dition, specimens of plain steel, hot- dipped tinplate and phosphated steel wire were included in the series. Twelve different paints were applied, including linseed oil paints, nitro- 64—THE IRON AGE, December 6, 1945 cellulose lacquer, stoving paints and air drying japans. A diagonal scratch, 2 in. long and penetrating to the steel, was made on the face of each panel with a sharp-pointed knife. The specimen panels were subjected to three conditions: outdoor exposure; accelerated weathering and acceler- ated corrosion. These panels were ex- amined at intervals during the test for the onset and development of rust, special attention being paid to the behavior at the scratch mark. On the whole, there was no appreciable breakdown of the paint coatings, but rusting occurred underneath the paint; in some cases patches of paint were blistered. In spite of the long duration of the tests there was, with few exceptions, not much rust to be seen at the painted surface. On some panels there was appreciable spread of rust from the scratch, but on others where there was an equal spread, it was not noticeable as the paint coating was not much disturbed thereby. With every painting system the corrosion of the plain steel panel was much greater than that of any of the treated panels. It was also no- ticed that on the whole the results were more favorable to the pack- rolled than to the cold-reduced steel— an unexpected result which may be due to the somewhat rougher surface of the former. Comparison of the electrotinned panels revealed no ap- preciable difference between the coat- ings from the acid bath and those from the alkaline bath. The 0.00003-in. tin coating was found more _ effective than the 0.000008-in. coating, but the 0.000008- in. coating was remarkably effective when compared with plain steel. In stoving paints the thinnest tin coating gave little effective protection, pos- sibly owing to diffusion of the tin into the steel during the stoving treatment at 302° F, with formation of a sur- face layer of the compound FeSn:. In general, the as-deposited tin coatings were better than those that had been melted, a fact which may again be connected with the rougher surface. On the whole, the relatively thick, 0.000076-in., commercial hot- tinned coating was very effective, but adhesion of the paint did not appear to be as good as with the electrotinned coatings. In many cases, panels of hot-tinned tinplate were remarkably free from isolated rust spots, but rust did spread from the edges and from the scratch mark. Treatment of the tinned surface with an oxide film gave an improvement in rust resistance in three cases out of four and appeared to improve the adhesion of the paint. The phosphate treatment occupied an intermediate position among the tin treatments. king ormed mate- work, is the ice of treat- 88 on iently e cold cause e rate spring imum Ss well mini- ‘form- ec Mi- ent of to se- makes er to tional oy. 10 ap- : coat- those was | the )0008- ‘ective 21. In ating » pos- n into tment a sur- la. d tin 2 that | may ugher ‘tively hot- e, but |ppear tinned els of rkably t rust from of the 1 gave nee in yeared paint. ied an he tin Emergency Gas Welding of Magnesium Parts ROKEN or cracked magnesium parts usually can be sufficiently repaired by gas welding to put them back into use, although such practice should generally be considered only as an expedient pending the obtain- ing of a replacement part—a consid- eration particularly true in the case of castings repairs. Various methods for emergency repair of magnesium parts by gas welding have been the subject of a study recently completed by the research engineers of the Dow Chemical Co. Emergency welding of magnesium parts often requires deviation from normal practice in order to put the pieces back into service quickly. Multiple bead welds may be justified on this ground, along with welding of sections impossible to clean thor- oughly, the welding of cast metal, and other considerations. Recommended specifications of welding equipment when using oxyacetylene gas are shown in the accompanying table. An ordinary oxyacetylene torch can be used, with tips on hand whose orifice diameters range from 0.035 to 0.081 in., the larger sizes standing by for use in heavy sections which may occasionally require them. Magnesium alloy weld- ing rod is used, of the same com- position as the material being welded. If an identical composition is not available, a rod of magnesium alloy slightly lower in melting point may be substituted. One expedient, if standard welding rod is not available, is the use of strips cut from sheet, extrusions or castings, thoroughly cleaned. See “Tooling for Magnesium Welding,” Tue Iron Ace, Aug. 31, 1944; and “Gas and Heliarc Welding of Magnesium Al- loys,” issue of May 3, 1945. A welding flux must be used to prevent oxidation of the metal dur- ing the oxyacetylene welding of mag- nesium. Recommended are Dow 450 and 460 welding fluxes; if not avail- able most aluminum welding fluxes will be satisfactory. Welders should wear gloves and the usual type of welding goggles. Blue glass gives best visibility. The first step in repair is thorough cleaning of the casting, removing grease, oil, dirt, chemical coatings, Guide to Selection and Regulation of Oxyacetylene Welding Equipment 0.020 0.032 0.040 0.051 0.064 0.072 0.081 0.091 0.128 an sssssssses ecoocooseco paint and the like. Alkaline cleaners, carbon tetrachloride, gasoline or soap and water can be used. After cleaning, the repair area must be prepared. Edges of the de- fect must be dressed down to clean, sound metal by routing, filing, chip- ping, scraping, or similar means, The slope of the sides of the defect should be about 45°. If a defect penetrates the wall of the casting, a land or root surface about 1/16 in. should be left on the bottom side. The casting sur- face around the zone should also be thoroughly cleaned. The first step in the welding op- peration is application of the flux paste with a small brush to the area edges. Before starting to weld, the torch should be adjusted to a neutral or slightly reducing flame. Adjust- ment should be to a %-in. inner cone or until such inner cone slightly “feathers” at the tip when the oxygen pressure is lowered. The casting should be preheated by torch or in furnace to about 650°F. This level can be approximately iden- tified by marking the casting with ordinary blue carpenter’s chalk which will turn white at temperature of ap- proximately 600°F. The welding flame should then be fanned over the area, and as the metal begins to melt the rod is dipped into the molten puddle and then withdrawn as _ sufficient molten metal is obtained. Actual welding then follows with the flame moving forward in a straight line and the torch inclined about 45° to the work. Welds should be made in one continuous pass if possible, to SSSSSEaas oo wo wo Wo ww GD = ssssssssse GF OF OF GH GF OF OH 8 69 G2 62 C0 mt mt mt mt sssssssce GF GH GF OF GT 68 Go WO hold surrounding metal up to tem- perature. If insufficient heating is maintained, indicated by cracking, a larger tip size should be employed. After welding the casting should be postheated for 1 hr in a furnace at about 650°F. If no furnace is available, a gas flame can be played over the entire casting to hold it at that temperature, after which cooling should be permitted in quiet air. After cooling, excess flux should be removed by scrubbing with a stiff bristle brush and hot water. When magnesium fittings or cast- ings are gas welded to sheet or ex- trusions, the edges of heavy cast sec- tions should be tapered or beveled down to the thickness of the sheet or extrusion. If this thickness exceeds % in., it likewise should be dressed down. The casting should be pre- heated to about 650°F, and during actual welding the flame should be directed principally upon the casting. Repair of wrought magnesium parts by gas welding does not require pre- heating, but otherwise the procedure is the same. After cleaning of gas welds on com- pletion, they should be immersed for 1 min in a chrome pickle solution con- sisting of 1% pt of nitric acid and 1% Ib of sodium dichromate, plus enough water to make 1 gal of solu- tion. After thorough rinsing and drying the parts should be painted. If a chrome pickle bath is not avail- able, on emergency jobs, gas welded parts should be painted immediately after scrubbing with brush and hot water. THE IRON AGE, D