The Iron Age 1945-12-13: Vol 156 Iss 24

owed Jetob P| er an ir aga plan 1 thei the 17 etobe er an atro ofa ared b en dis opmen . Kers rs buil 1 usag’ ee BSE Sa ROR J. HW. VAN President ond Editorial Director c. S$. BAUR . Vice-President & General Manager * HH. & LEONARD Assistant General Manager B. H. HAYES Advertising Manager ©. L. JOHNSON, Manager Reader Service and Market Research. R. E. BAUR, Production a a Manager R. E. CLEARY, Technical Research and Promotion Manager oO oO ° Executive Offices Chestnut and 5Séth Sts. Philadelphia 39, Pa., U.S.A. Editorial and Advertising Offices 100 East 42nd St., New York 17, N.Y., U.S.A, Business cites York 17 New York 17 42nd St. "iM. oln8s F. BLAIR R. M. - Bldg. f ee H. K. Es rts, 7310 Woodward Ave P. O, Box 8! + RAYMOND KAY 2420 Cheremoya Ave. °o ° ° Owned and Published by CHILTON COMPANY (Incorporated) OFFICERS AND DIRECTORS Cc. A. MUSSELMAN, Chairman ~ JOS. S. HILDRETH, President GEORGE H. GRIFFITHS Vice-President _ EVERIT B. TERHUNE Vice-Pretident J. H. VAN DEVENTER Vice-President C. $. 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. ° ° ° ton Editorial PAUL WOOTON Washington Representative ° ° ° Member, Audit Bureau of Circulation Vol. 156, No. 24 This Weele in The. December 13, 1945 Editorial Let’s Utilize Productivity. . Technical Articles Setup Charts for Bullard- Mult-Au-Matics Heat Treating, Forming & Weldi Effect of Work Position in Face Electrodeposition of Metals on Plastics Cycle Annealing of Hypo-Eutectoid Steels. Metallizing as a Production Process Electric Furnace Conference Report 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 Semifinished Steel Prices Alloy Steel Prices _. Fabricated Steel Products Prices Warehouse Steel and Pig Iron Prices Ferroalloy Prices New Construction October Foundry Production in Philadelphia Rust Furnace Co. Gets Large Contract Russian Steel Production Methods Shrinkages in Strategic Stocks Mesabi Taconite Linter Costs Pierce Heads Alloy Sales Program India Pig Iron Price Higher. . World’s Most Powerful Locomotive Army Surplus Disposition ASME Awards in New York Pittsburgh Coal Merger Machinery Dealers’ Committees Allegheny-Ludlum Buys Arnold pens Scrap Institute Elects... M.I *. Radar Research Index to Advertisers 51 54 75S Alclad (Part II) 59 illing (Part I) 65 72 74 79 53 82 94 98 102 104 107 . 122 124-25 126-27 128 130 . 131 132 133 134 135 169 170 171 173 174 140 140 142 144 152 154 156 158 . 162 164 267-68 No Mistaking Ryerson Alloys Certified Quality Demands Positive Identification All Ryerson alloy steels are doubly identified. Each bar is painted with colors which indicate the AISI analysis type and the condition of the steel. Larger bars are individually stamped, and smaller bars are bundled and tagged with a heat symbol assigned to the specific heat from which the bars are rolled. This double identification is as unmistakable as finger printing. All this is important to you because: Each heat of alloy steel in Ryerson stocks has been carefully selected, and thoroughly tested. The exact chemical analysis, as well as the hardenability response for that steel are known. This information, together with an interpretation of obtainable physical properties after quenching and drawing, is assembled in the form of an Alloy Steel Report that is cross referenced with Heat identification. A copy of the Report is sent with each shipment of that particular steel. Thus, you receive steel that is Certified as to quality and performance ... plus a Report that serves as an accurate guide to best heat treatment. Take advantage of this identified quality and receive prompt, personal service. Joseph T. Ryerson & Son, Inc., Steel-Service Plants: Chicago, Milwaukee, Detroit, St. Louis, Cincinnati, Cleve- land, Pittsburgh, Philadelphia, Buffalo, New York, Boston. December 13, 1945 J. H. VAN DEVENTER President and Editorial Director Cc. S. BAUR Vice-President and General Manager EE T. W. Lurene News Morkets Editor T. C. CAMPBELL Machine Tool Editor...H. E. LINSLEY ° ° ° Associate Editors F. J. WINTERS J. ALBIN JOHN ANTHONY . Hi. ASEL &. S. KOPECKI E A. TOWNE A. J. SPEAR Foreign Editors Europe ...... .... SACK R, HIGHT _ Canada (Contrib.)...F. SANDERSON T. E& LLOYD Pittsburgh 22 428 Pork Bidg. Cc. T. POST Chicago 3 1134 Otis Bidg. National Press Bidg. W. A. LLOYD Cleveland 14 1016 Guardian Bidg. S. H. BRAMS Detroit 2 7310 Woodward Ave. OSGOOD MURDOCK WORTH HALE San Francisco 3 1355 Market St. Editorial Correspondents n ROBERT McINTOSH Cincinnati L. C. DEAN ter Buffalo of G, FRAZAR ‘ Boston ith at HUGH SHARP , Milwaukee a R. RAYMOND KAY ind Les Angeles an JOHN C. McCUNE Birmingham ive ROY EDMONDS St. Louls Se: JAMES DOUGLAS Seattle Let's Utilize Productivity | Regional News and Technical Ed'tors | OLLECTIVE bargaining is here to stay, but it must be real bargain- ing. In the oid days the employer, particularly the absentee owner employer used his power to keep labor down. Today the pen- dulum has swung, as pendulums do, to the other extreme and labor, with a similar club uses its power to keep the upper hand and the em- ployer down. Instead of trying to keep each other down, which is a futile and non-constructive endeavor, they should try to raise each other up. In earlier times, before the concentration of productive capacity and of labor power had developed, a strike or 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 trade or service. Byt when the scale of operations increases to that of today and threatens to paralyze activity broadly throughout the country, the situation emerges from that of a private controversy and becomes a public problem. If collective bargaining is to endure, it must be between equally re- sponsible parties. Labor contracts, like all others, should be enforceable by law. If management were to be assured that organized labor was amenable to law, like the rest of us’ and could not throw over a contract as non- chalantly as you can toss a cigar butt from a ferry-boat, it would sit down at the conference table with the assurance that there would not be a thumb tack, sharp end up, on its seat. So point number one, as I see it is to remove the slant from the col- lective bargaining table and level its legs. That’s a job for Congress. Perhaps the greatest brake of all on our economic progress is public indifference to productivity because by and large it does not know what it really is and does. Maximum productivity should and can mean maximum wages. It should and can mean maximum return on investment. It should and can mean more for the consumer’s dollar of income in every walk of life. It seems to me that enlightened labor leadership, together with enlight- ened management, could do a great deal to enlighten the public on this vital truth. But simple enlightenment is not enough. I think we should do some- thing to make increased productivity worth-while. That means the shar- ing of its fruits on an equitable basis. What we need more generally in this country are stronger incentives to produce. Progressive manage- ment must see to it that an equitable share of productivity gains are passed on to labor in the form of higher wages or preferably some method of profit sharing, and to the consumer in the form of lower prices. These things are fundamental to prosperity and sound manage- ment-labor relations. With our resources in materials and engineering knowledge and labor skill, there is virtually no limit to what we can do, providing we acknowledge the power of productivity and get together to make it work for us. Feshyoat Ne) a ania. b-vallag ee ee ae ot nit ery Sena ener nee als oa 8 *e - ce seer a a aa eae Cores | Etching... Another Step in Inland Quality Control @ Among the many product control methods used by Inland are hydrochloric acid etch tests. Through deep etching the character of the internal structure is clearly revealed for visual examination: Samples for these tests are taken from billets, slabs and blooms, rushed to the laboratory and sawed apart to expose a cross section. Each sample is then etched 30 minutes in a 50% hydrochloric acid in water bath heated to 160°F. Then the etched surface is washed, scrubbed and dried. Following this the samples are laid out on inspection benches where Inland metallurgists critically examine each piece. The etch test and all other product controls are completed and reported before steel is shipped by Inland. Inland Steel Co., 38 S. Dearborn Street, Chicago 3, Illinois. 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. CLES. eee ee: - NEWSFRONT (R00 AGE . Dec, Ll, 1945 Predicated on the assumption that steel producers here have not been exporting steel in appropriate quantities since the end of the war, CPA is reported to be studying plans for the enforced allocation of 4 to 5 million tons of steel abroad. High speed long distance telephone connections are contemplated by the Bell System about 1955 to 1960 when the current development program for dialing by sub- scribers to any telephone in the country is expected to be completed. Meanwhile, the first stage of the Inter—toll Dialing program in which a subscriber's long jistance operator can dial direct to a distant toll area, has gone into operation between New York and Philadelphia. » Westinghouse has been shopping around for a plant site for its motor produc— tion in order to make room at Pittsburgh for switchgear and other facilities. ifter examining some 15 plants, it appears that the Curtiss—Wright plant at tuffalo may be selected, depending on price negotiations with the government. > The recently announced program for Bethlehem Steel expansion at Los Angeles las grown to a prospective 100 pct expansion of facilities and contemplates four iore Openhearths in addition to the new one. >» Outstanding advantage of the plating of metals on plastics is its increased sorrosion resistance. Resistance to salt water and industrial atmospheres is ex- ellent since there is no electrolytic action as when a metal is plated on the isual metallic base. And the plastic itself experiences improved properties. Absorption of oils, solvents and moisture is eliminated. Tensile, impact and flexural strength is increased, and resistance to abrasion and distortion under heat. > Excellent machining properties of aluminum alloy 75S are believed due to the zinc intermetallic compound which gives the metal free machining properties. With§ the use of tungsten carbide tools, properly ground, a better finish may be ob-— tained than on any other high strength wrought aluminum alloy. Less warpage is mcountered than in 24ST or 14ST ant tool life is appreciably greater. > To obtain a minimum grain size and structural homogeneity, hypo-eutectoid illoy steels when being conditioned for machining and cold working should be pre- lormalized from a temperature just above their respective AcS temperatures. Small grain size thus achieved persists through the subsequent austenizing and softening treatments and accelerates final spheroidization. ° » RCF is reported to be preparing to ask for competitive bids with a floor for the Geneva Steel plant. Steel interests think the floor will be too high. a > Unless proposed stockpiling legislation is enacted before Jan. 5, SPA may pro- ceed to recommend disposal of surplus strategic metals and minerals now held by RFC, Treasury and the armed services. » The House version of the Full Employment Bill now designated as the "Employ- nent Production Act" eliminates all reference to a "right" to a job contained in the original bill and aims at "high levels" of employment, production and pur- chasing power. > OWMR deputy director Hans A. Klagsbrunn is the authority for the statement that military purchases have been cut from about $40 billion in early August to around $13 billion. Some 40,000 contracts out of more than 120,000 that were on the books have been settled. >» Pointing out that the physical first steps toward reconversion have gone well, the same authority said that the government had nearly 56,000 requests between V—J Day and Nov. 1 for clearances of government-owned machinery cut of plants. That's an average of better than 700 a day. Thirty-five thousand clearances have been completed, two-thirds of them in 40 days or less after the request. » While immediate British auto production is in models identical to prewar cars, some small firms are redesigning their products completely. .A typical example, the Jowett Javelin breaks away from conventional body design for airplane styling, and features a horizontally opposed four cylinder engine. i | | sain anes ential ee gi al na i Ne ie F's. 2—Chart of fee IMILAR in its operation to a six K, or eight-station automatic screw machine the Type D Bullard Mult-au-matic is basically designed to machine castings or forgings in- stead of bar stock, and therefore each spindle must be in the form of a chuck instead of a collet, and each piece must be inserted and removed by hand at the completion of each sequence of operations. Since these Pet tale dit bed. buabedicenkchbob Lode CCCCEE Dar +t | - ee EL ELE beh ohhh tthe 2 o Oi S SR GSS SR Bip $9? SSssTVSSsss Sad Haves sassgasseseses a ee pe Setup Charts for Bullard M machines are designed for the turning of castings or forgings it is quite _ reasonable to assume that the simplest design would be to erect the machine on a vertical axis. This provides easier accessibility and facilitates handling of the castings in the chucks. It also permits more compactness in design with resultant economy in floor space. The base section of the Bullard is round in form with a turntable S385 GRA LVSTVINKaR gegesceeann Btsysnese Change gears F IG. |—Chart of feeds and speeds for six and eight-spindle, Type D, 8-in. Bullard Mult-Au-Matics with back gears normal. WwwMwuwdcds = . +) aoe DM OT OB A A Sk OS MS i 7 SEE ECE Eee Ee er ee et eT tte ce des ere ee ee Asttdeds bob bel dedstlchalake net deen SAC COCO eee Pd wr | et me | fe LT pent pois} ofa] Rolgb te teblbE LLL ELLs Peabo talatc erate wow FF SCSSLSSNVTS SRBSBRERKS Change gears 54—THE IRON AGE, December 13, 1945 ds and speeds for six and eight-spindle, Type D, 8-in. Bullard Mult-Au-Matics with back gears reversed. ring surrounding the central column. The turntable supports the chucks which are free to rotate thereon. The lubricant and coolant reservoirs are beneath the turntable, inside the base, On each machine there is a loading station where the castings or forgings are chucked or removed, while the re- maining stations are evenly dis- tributed around the machine for the cutting operations. There may be either five or seven operating sta- tions depending upon whether it is a six or an eight-station machine. At each station the cutting tools are mounted upon slides which are ar- ranged to move in vertical ways. These are supported on the central column which encloses the drive and indexing mechanisms. The control mechanisms are located within the overhead enclosure which is known as the feed works area. The main drive motor is located on top of the machine, and transmits its energy through bevel gears in the main drive bracket. This energy is applied through a main clutch located just below the main drive bracket, with a bypass drive through the clutch to the indexing units. The timing of the machine is entirely dependent upon this indexing drive which con- trols the mechanism by which the cut- ting cycle is initiated. While the index lock lever is “in” the indexing drum is held in such a way as to disengage the indexing clutch so that nothing happens. Nor- mally the cutting cycle is initiated by the functioning of the indexing trips which are located at each sta- tion. The last of these to operate is the one that initiates the cycle. If the indexing trip at each station is engaged and the index lock lever is released, the indexing drum is par- tially rotated by a spring. This mo tion actuates the indexing clutch s0 as to engage the indexing mechanism with the indexing drive shaft, caus- ing the machine to index. This motion is accomplished by one revolution of the center shaft which thereby actuates the geneva move ment and at the same time rotates the control and indexing drums through one revolution. This motion of the control drum engages the control | levers spond and ¢ there dexin tion actus lever elute! mech stant be “4 woul trol of th unde dl Mult-Au-Matics column. chucks on. The irs are 1e base, loading orgings the re- y dis- for the lay be ig sta- it is a ne. At ls are ire ar- ways, central ve and located which a. The on top its its in the rgy is ocated racket, clutch ing of endent h con- 1e cut- s “in” uch a lexing Nor- tiated lexing n sta- ate is e. If ion is rer is par- 3 mo- ch so anism caus- y one which nove- s the ‘ough f the ntrol § levers at each station with the corre- sponding control stops on the drum, and compresses the actuating spring, thereby cocking it for the next in- dexing cycle. The corresponding rota- tion of the control drum causes the actuation of the traverse engaging levers which cause the traversing clutches to tend to close on the feed mechanisms. . Under normal circum- stances the index lock lever would not be “in” and‘the indexing mechanism would be controlled by the index con- trol levers at each station. The last of these to lift would initiate the cycle under automatic operation. Spindle and Feed Mechanism The main, clutch controls the spin- dle and feed mechanisms. It is con- trolled by a main clutch operating ring that can be actuated by hand at any station on the machine. Normally the main clutch is engaged. The gear on the main clutch, referred to as the main clutch gear, drives a main ring gear which surrounds the central shaft. This in turn drives the various spindle drive shafts through change gears which are located in the upper works on top of the feed mechanisms at each station. The feed drives are driven by the spindle drive shafts in a manner similar to the Gridley type automatic screw machines, wherein a direct relationship of feed per revolu- tion is established by the feed change gears and is unaffected by the spindle change gears. However, there are two differences that must be considered in comparing this feed with the Gridley automatics. The first is that each station has its own individual drive which can be different in both feed and speed from any other station. And, second, the high speed or traverse operation is obtained by means of a high-low speed transfer clutch, as against the over- running clutch that is customarily used in Gridley automatics. The traverse side of this clutch is driven from the shaft head of the spindle change gears so as to give a constant traversing speed under all conditions. The feed side is driven through com- pound feed change gears which are driven by the spindle drive shaft. Actuating the clutch causes the feed worm to be rotated in either high or By JOHN J. MEADOWS Consulting Engineer, New York . . » When setting up a Bullard Mult-Au-Matic it is no longer neces sary for the setup man to spend valuable time and run the risk of error in making his own calculations. Charts are presented here- with to enable him to see at a glance the correct pair of change gears for each spindle speed and rate of feed. These charts are similar to the ones presented in THE IRON AGE, July and Augus?, 1945, for use with automatic screw machines. Change gears 1G. 3—Chart of feeds and speeds for six ond eight-spindle, Type D, 12-in. Bullard F Mult-Au-Matics with back geors normal. 60 0.260 | re 240 roo +4 cI 0.240 eT Eee cc 0.220 TTT tio }— 0.180 th baw tt | oi et aw * ho am i Pet Tis — p01 pee Ee 0.020 set Herre ett SRR See BR ESBsUAsSERGRALOVES * SEER TAT SoaaRe a SSOTSSsssescaasesecess hange gears 1G. 4—Chart of feeds and speeds for six and eight-spindle, Type D, !2-in. Bullard F Mult-Au-Maties with back gears reversed. THE IRON AGE, December 13, 1948—85 low speed. The feed worm drives the feed drum gear which rotates the feed drum on which is mounted the feed cam. er PSS 2 Sumerian Oat ais hd dem Hien are n ng disk an : ee Py i oe a ed 5 brake lever plunger and traverse = at Pe hete pet. pe ee eke oe eee | aed oan auxiliary cam. The function of the odif | CCEEEEEE ECE EE 77 Rng brake leer olanger io actnte te I id z / eh a RL - es brake momentarily in order to stop rvs e the feed at the high point of the with- a 4 drawal stroke where indexing takes = LT TT TV reeds? eo place. The timing disk is the mechan- —_ | +] noe) ism where adjustments are made in ‘ . | tt order to regulate the length of each ” | P ee ee oe part of the cycle. On the timing disk es ——— next | La ft are located the feed engaging and re- ote: | Bree : turn dogs, the stop dog, and the in- the dexing trip dog. The first two are for adjustable, and the latter two fixed into Change gears as they bear definite relationships to oa F IG. 5—Chart of feeds and speeds for six-spindle, Type D, 16-in. Bullard Mult-Au-Maties the machining cycle. The feed dog oa with back gears normal. actuates the feed clutch to throw the b 280 feed drum from traversing speed to oe | cutting speed, and the return dog to ehe pont 260 return the drum to traversing speed init MH | 240 after the cutting cycle has been com- by ‘e 220 pleted, at the end of the dwell. duis tI 200 The stop dog is for the purpose cou (3) E of returning the clutch to neutral its 14] al80 when the slide follower reaches the eat 1} » 160 top of the feed cam preparatoy to in- op i] } dexing. This motion is anticipatory the treat 3 2120 in character and serves to place the th Wii] s clutch lever spring in compressing ot am through the transfer of the shift cam | 80 rod into the neutral position while the 60 feed clutch lever is still deflected by a 1 the neutralizing cam. It is this spring w | 40 compression that causes the clutch m Bhd 20 mie lever to deflect into the neutral posi- dt Wee | 0 Lt ete ee tion as soon as the follower leaves the t HPT | EUARRR AE RSHBSORSRSST TY SPSS SS RET ARBRERES taverns lobe of the neutraliaing com. a Hi | Change gears This accomplishes the exact timing P He F IS. 6—Chart of feeds and speeds for six-spindle, Type D, 16-in. Bullard Mult-Au-Matics of the clutch neutralization at the top ¢ i} with back gears reversed. of the slide motion when the feed a i 300 drum following is at the topmost n a iit position preparatory to indexing. | 4) 280 Timed with this motion is the index ‘ i 260 trip cam which deflects the corre- ‘ i 240 sponding index control lever. The 220 simultaneous lifting of all of these 200 levers results in the release of the £ index control drum which in tum initiates the indexing of the machine. The rotation of the indexing or years PL — ndle SS oOo 3140 central shaft causes the simultaneous rotation of the upper control drum (100 upon which is mounted the main : 80 clutch operating cam. This cam dis- 60 engages the main clutch and thereby stops the feed works during the in- dexing operation. This function occurs right after neutralization of 0 010 the feed cam layer by the timing of Bee eee TEST Tei ieee eco tooo the neutralizing cam. The feed works 4 RANRSRERRERSSS a are again set in motion, at the com- : a . : Hi hid letion of the indexing operation, by Ve a4 | ‘ FIs. 7—Chart of feeds and speeds for eight-spindle, Type D, !6-in. Bullard Mult-Au-Matics i eraversh diel a which is ee ! with back gears normal. y 56—THE IRON AGE, December 13, 1945 $5. 227 F a? F mPeTeRnasBrnaecFts &S — so ed st os actuated by the corresponding traverse trip dog on the upper control drum at the completion of its indexing rota- tion. At the same moment the main drive clutch is re-engaged. In auto- matic operation this cycle is repetitive. During the indexing operation a modified geneva movement pumps the carrier from one positiom to the next, while the motion of the carrier is utilized to cam each sliding pinion on the spindle shafts longitudinally out of engagement with the spindle gears. This permits the movement of the spindles from one position to the next in spite of the stationary char- acter of the spindle drive shafts. As the carrier is indexed into position for the next operation it is locked into position by means of a locking pin and a carrier binder pin, both of which are cammed into position by a locking pin cam which is se- cured to the central or indexing shaft. As the indexing operation is initiated these pins are withdrawn by means of their levers, the with- drawing of which is initiated by the compression of a spring followed by its sudden release. This tends to catapult the pin out of the hole, an operation made necessary because of the wedge action used in securing the pin in the hole so as to prevent play or backlash. These machines are sometimes equipped for double indexing, in which case the carriage or carrier moves two stations instead of one, and duplicate tools are required for every two stations. In such cases the machines must be modified so as to provide two loading stations leaving only four or six operating positions available, depending upon the total number of stations on the machine. Of these only half that number of operations can be performed because of the duplication of operations. Use of Set-Up Charts The setting-up of these machines is not too complicated if the func- tional operations as described above are properly understood. In order to assist the set-up man in his function, set-up charts have been devised. From inspection it can readily be seen that the fundamentals of setting-up are quite simple. For each size two charts are provided, one with back gears normal and the other with back gears reversed. Reversing the back gears serves to increase the range of feeds for heavier cuts. The charts are used as follows: Let it be assumed that an 8-in. six-spindle Type D Bullard is to be SFBGRS SANGASSS SST SH SF MATAR ADRES SaSVsseseesansss SERSSSESISSSSSRs &¢ oO Change gears pie 8—Chart of feeds and = for eight-spindle, Type D, !6-in. Bullard Mult-Au-Matics gears reversed. used. Three different spindle speeds are to be used, three cutting opera- tions are to be done at 180 rpm, one is to be done at 240 rpm, and one at 300 rpm. Two operations are to be performed at 0.040 in. per rev, one at 0.100 in. per rev, and two at 0.006 in. per rev. Either of the 8-in. Bullard charts can be used to determine spindle change gears, while both charts will have to be used for feeds. Entering either chart along the left hand border at 180 rpm the horizontal line is followed to its intersection with the spindle speed curve. This will occur between two sets of change gears 51/29 and 52/28, either of which will give approximately the r w 45 Spindle speed Soke speed desired, the first will give 176 rpm and the other 185.5 rpm. In like manner the chart is entered at 240 rpm and the curve will be in- tersected between the change gears 56/24 and 57/23. The 300 rpm line intersects the curve directly upon the 60/20 change gear line. The feed change gears are determined by analysis from the right hand side of the charts. The 0.040-in. feed can be obtained in either of two ways. With the back gears normal the feed gear curve is intersected approximately on the 56/24 change gear line, while with back gears reversed the intersection is approx- imately on the 26/54 change gear line. One is actually above the de- Change ¢ care Fie: 9—Chart of ame? > speeds for eight spindle, Type D, 16-in. to 23-in. Bullard normal. ult-Au-Matics with back gears THE IRON AGE, December 13, 1945—57 ai a Sd ee ods 4 : 2 of ae hte \ TPT +: oe aT ee HE CL OOO as a> mar erwnmeneme aes sett sate scatanga te aneettne CC e ae SRI 20 enna Naot the work lies between the 0° and the 70° 45’ work positions. (4) Cutter life can be improved by using corner angles greater than 15° when it becomes necessary to operate a face mill within the 0° to 70° 45’ work positions. (5) When a 25°, 35° or 45° cor- ner angle is used, the cutter life for the 70° 45’ to 100° work position is only from 50 to 60 pct of that ob- tained from a face mill which has a 15° corner angle. (6) Any face mill with a 45° corner angle will produce the maxi- mum cutter life when the 15° cor- ner angle is disregarded and prac- tically no attention at all is given to work positioning. The 35° and then the 25° corner angles rate next in the order given. (7) Mediocre but somewhat con- sistent results can be obtained with a face mill having a diameter slightly larger than the work width, provided that it has a 45° corner angle. (8) The face mill can be adapted to various face milling operations by grinding an appropriate corner angle on it and then properly posi- tioning the cutter entry edge of the work to the cutter. This indicates the possibility of standardizing carbide-tipped face mills and adapt- ing them to a large number of jobs. (9) Cutter life was shortest for the 45° work position when operat- ing a face mill with a 15° corner angle at all feeds per tooth. When the corner angle was changed to either 25°, or 35°, or 45°, the cutter life was considerably longer for the same position. However, the one work position which gave the re- duced cutter life was transferred to two positions, one at 40° and the other at 50°, either side of the 45° position. This set of conditions is worth further analysis. It must be kept in mind that all conclusions were reached as a result of using a face mil] on work having a 1%-in. wide cut. While these tests were being run, it was observed that when runs were made at the critical 45° work entry position, the cutter life could be increased many times for some cuts wider than 1% in., even though the stock removal was much greater. This seems to indicate that the position where a cutter tooth leaves the work or a possible varia- tion in cutter-flywheel-spindle mo- mentum may affect cutter life. This is another phase of work position- ing which will be given extensive study in the future. Electrodeposition of Metals on Plastics HE process of plating on plastics is not intended to imitate metal but rather to yield a product that can- not be economically made of metal, Harold Narcus, chief chemist of the Plating Processes Corp., Holyoke, Mass., writes in a paper contributed to the Electrochemical Society sym- posium on “Before and After Plat- ing.” More intricate shapes can be readily molded and electroplated than can be fabricated in metal and electro- plated. As the weight added by the application of metal to the plastic is usually negligible, the plated plastic part still maintains a weight advan- tage over a similar part made of metal. By plating on plastics, undesirable properties of the plastics, such as absorption of oils, solvents and moist- ure, which may cause swelling or distortion of the basis organic ma- terial, are eliminated by proper choice and thickness of the outer metal. Weatherability of the plastic is greatly increased and there is also an increase in tensile, impact and flexural strength and in resistance to abrasion and to distortion under heat. Probably the outstanding advantage of this type of plating is the greater corrosion resistance of a metallic de- posit when it is applied to a plastic material than to the usual metallic base. Resistance to salt water and industrial atmospheres is excellent since there is no electrolytic action. The inert, nonmetallic plastic coating 58—THE IRON AGE, December 13, 1945 and hence of the entire plated part. Chemical reduction to form a con- ductive metal film on nonconducting surfaces such as plastics has many advantages over other available methods. The two main advantages of the chemical reduction method, es- pecially the process utilizing silver films, are (1) the silver film covers the entire surface of the plastic regard- less of its shape so that proper elec- tric contact is established over the en- tire surface to be electroplated and (2) the thickness of the very thin silver film can be controlled so as to permit subsequent electrodeposition of an outer metal in accurately known thicknesses. This method is best adapted to a commercial production setup; it is’ more economical and gives more uniform, controllable re- sults than any of the other prevailing methods for depositing metals on plastics. Different types of plastics do not receive the same preparatory treat- ment prior to application of the con- ductive silver film. Plastics such as phenolics, ureas, cellulose nitrates, styrenes and methyl methacrylates are given a slight roughening before cleaning and sensitizing while cellu- lose acetates must undergo an addi- tional priming operation before the surface is highly receptive to a con- tinuous, adherent silver film. Rubber compounds are prepared for electro- deposition by immersion in benzol or acetone for roughening after which they are cleaned and _ sensitized. Casein plastics use water as the swell- ing agent or roughener. Urea-formal- dehyde resins are roughened in a 10 pet hydrochloric acid sdlution and treated in a 1 pct ammoniacal ferrous sulfate solution for 15 min at 59° F. They are then placed in a 2 pct cop- per sulfate solution for 8 min at 86° F. The preparation of the nonmetallic surface prior to the deposition of the silver film involves the following steps: (1) Slight roughening or de- glazing of the plastic surface; (2) cleaning the surfaces; (8) sensitizing the surface; (4) formation of the sil- ver film by chemical reduction; (5) electrodeposition of an intermediate layer of metal, and (6) application of an outer layer of metal. Metals other than silver can, of course, be deposited as well. Copper films can be deposited on plastics by the reduction of a copper solution with formaldehyde or hydrazine. Lead films can be applied using an aqueous solution of the nitrate, acetate or tar- trate, reducing with a solution of thiourea in the presence of sodium or potassium hydroxide. Gold films can be formed from an aqueous solution of gold chloride by using invert sugar, alcohol, citric acid or formaldehyde as reducing agents. Nickel films are de- posited from nickel carbonyl decom- posed at 302° F. he is Pepe & ns @ we eet Re eS ~ . -— By MITCHELL RASKIN Assistant Process Engineer, Northrop Aircraft Inc. 75SO are very similar to those of 24S0, although greater pres- sures are required and higher spring- back is encountered due to the higher tensile and compressive properties. Local elongation is also slightly greater than in 24SO. For operations where loca] forming is involved, such as bending, 75SO has been found equivalent or superior to 24S0, and although it has a tendency to neck prematurely, thus tending to limit the elongation in stretch flanges and lightening holes, the strain required to accomplish the making of most parts is less than the limiting elonga- tion. Hence no difficulty has been ex- perienced in performing such opera- tions in the SO temper. The slightly inferior compression properties of 75SO do not interfere with either drawing or drop hammer operations. In the as-quenched condition, 75S has forming properties only slightly inferior to those of 24SQ. The elonga- tion is considerably greater up to the point where necking starts, and the high uniform elongation and general resistance to necking make it a very satisfactory materia] for stretch press forming. Forming in the as-quenched condition is highly desirable since ductility is good, and warpage from subsequent solution heat treatment is eliminated. The age-hardening characteristics, however, make speed in forming an absolute necessity. After approximately 1 month at room temperature aging, 75SW reaches sufficient stability to enable predictions of formability to be made. Ftsso a: properties possesed by Heat Treating, Forming, And Welding 75S Alclad . « « In the first part of this article, published last week, the author discussed the metallurgy and heat treatment of the important 75S alloy. In this second and concluding part, he points out the precau- tions to be observed in forming and spot welding, and describes a method of hot dimpling. Original tests with the resistance heat- ing for dimpling were made by Dan Finch of the University of Cali- fornia. Northrop developed and perfected its use for practical production. The local and uniform elongation is much less than in the SQ temper, but approximates that of 24ST. In gen- eral 75SW Alclad has similar form- ing properties to 24ST Alclad. The great advantage of forming in the SW temper is that the operation is not restricted to a short working period, as in the SQ temper, and the material is still free from subsequent warpage due to heat treatment. There is a possible chance that superheated warehouses or transportation com- partments may accelerate the aging of SW and thus reduce its ductility, but after 1 year’s use of the material Northrop has not encountered this difficulty. In the ST condition 75S Alclad possesses a yield strength approach- ing the ultimate, and it is not un- common for the yield strength to be 69,000 to 70,000 psi with an ultimate of 78,000 to 80,000 psi. This results in a very small plastic or ductile range. Uniform and local elongation are only two thirds that of 24ST, and springback is very great. Hand forming, hydro press, and most other forming operations are therefore very difficult, but power brake or roll forming may be performed if an ade- quate bend radius is allowed. Increased temperature (see fig. 6) lowers physical properties and uni- form elongation, but loca] elongation is considerably increased, thus making bending, joggling and dimpling con- siderably easier. Forming 75ST Al- clad at 350°F may be compared to a hypothetical temper between 75SQ and 75SW. The limiting factor in hot forming is adapting a practical meth- od of heating to the individual part. Some parts may be heated satisfac- torily in an oven or oil bath, by cal- rods in dies, or other conduction heat- ing devices; some can be heated only by resistance heating, while some can- not be adequately heated with any equipment. In determining the temper at which to fabricate a 758 part, production cost is, of course, the guiding factor. Parts requiring mild forming should be worked in the ST condition when- ever possible, since this eliminates the costly heat treating cycle, but if this cannot be done, every effort should be expended to form the part in the SW temper. Parts completed in this con- dition require only the comparatively THE IRON AGE, December 13, 1945—59 t : js i tie it SOE RIP ORE IO . | soanpmasceancen nee RLCMMEES MeO Se inexpensive, non-warping, aging heat treatment. Should the contours of a part make forming in the SW condi- tion either too difficult or impossible, and the time consumed is short, the work should be done in the SQ tem- per. If parts cannot be formed in any of the above tempers, the work should be done in the SO condition and checked for straightness after the solution heat treatment. In cases where long slender members are in- volved, or there are great differences in section, and warpage would be very difficult to remove, the forming should be done hot in the ST temper. In a few cases, parts which suffer little or no warpage may be formed in the SO temper to facilitate speed and ease of manufacture. Bending and Forming 75S Alclad, like 24S, has better form- ability when the direction of forming is across the grain rather than with the grain. Satisfactory bends at 90° may be made on the power, brake or hydro press as shown in tables II and III. The minimum radii shown in these tables may be obtained in production, providing all edges are carefully burred prior to forming, and all scratches, nicks and surface damage are removed by polishing. If rough edges are allowed to remain, even a 6T radius may be inadequate, and it is recommended that burrs be re- moved by polishing. Table IV gives the maximum allowable depth of scratches, and these values should not be exceeded if failure by cracking is to be avoided. Polishing should al- ways be perpendicular to the bend line. Bend failures sometimes break in a wavy pattern (See fig. 7), but on many occasions investigations have shown that failure was not due to excessive forming or notches, but rather to the presence of some in- homogeneity in the metal, such as inclusions or abnormally large con- stituent particles. (See fig. 8). These act as notches, but as they cannot be detected on the surface of the metal a certain amount of scrap is in- evitable during bending. The failure shown in fig. 7 was found to be due to a large particle of segregated chromium constituent. Recent im- provements in technique on the part of the metal fabricator have, how- ever, reduced the probability of such failures. Roll forming may be successfully performed in all tempers of 75S, pro- viding the same bend radius limita- tions specified for bending are fol- lowed. For hydro press forming, parts $0—THE IRON AGE, December 13, 1945 Sheet Thickness Z25ERE8 o 385 eeesessssss BR IS. 6— Effect of temperature upon critical elongation. Ratio of the Minimum Bend Radius to Sheet Thickness, 75ST Alclad Condition TABLE II Thickness, In. Minimum Bend Radius Up to 0.091 2T Over 0.091 3T All 3T All 4T .020 and 0.025 4T -032 and 0.040 4.6T -051 and over 5T TABLE Ill Minimum Bend Radii for 75ST Alclad Sheet Minimum Bend Radius ” ° SW n + BSsSesess88 ocoooooocoooo g2SSS8283s88 ocoooooooooo 60 eee o ’ ’ a Tensile specimen S50 S S o 40 8 = 30 2457 atmaximum load - 2-1n.gage length elongu — -_ Iniforrm rane tL before necking, [@@ | | ~~& 100 Temperature, °F 0 0 TABLE IV Maximum Allowable Depth of Scratch Material 75ST 0.064 and under... 75ST 0.072 through 0.091. . 75ST 0.102 and over which can be formed in the SO and SQ temper of 24S can likewise be formed in the same tempers in 75S. 75SW, however, behaves much the same as 24ST. Shrink flanges are slightly more difficult to form in 75SQ than in 24SQ, while stretch flanges are less difficult with 75SW than with 24ST. For forming lighten- ing holes also, the SW temper is superior to 24ST. Modified lightening holes and stretch flanges are the only hydro press operations in which 75S ean be formed satisfactorily in the ST temper. Spring back from a 90° bend is approximately 2° for the SO temper, 2%° for the SQ temper, and approximately the same as 24ST in the SW temper. In the SO condition deep recessed, beaded and corrugated parts may be formed by drop hammer operation as readily as 3SO, although some diffi- Parallel to Bend, In. culty may be encountered where a great deal of shrinking is required. 75SQ has the same drop hammer characteristics as 24SQ, but neither the W nor the T tempers are satisfac- tory for this type of operation. A similar relationship between 24S and 75S also exists in punch press opera- tions, although greater loads are re- quired for shearing on account of the higher shear strength of the latter material. In the ST temper some modified lightening holes may be formed on the punch press, but in general its use in this temper for punch press work should be dis- couraged, Dimpling Difficulties Dimpling offers some serious diffi- culties since the form of the dimple cannot be modified to suit the temper of the material, but must conform 1G. 7—Failure in 75ST Alclad 0.09! in. thick, showing the entl F wavy pattern frequently to standard rivet head design, and in most cases a temper cannot be se- lected to suit the dimpling opera- tion. Almost all dimpling must be done with the material in the T con- dition. Tools have long since been developed for satisfactory dimpling in 24ST, but these have been found use- less when applied to 75ST, and it has been necessary to design entirely new tools. By increasing the punch diameter and the die radius angle, and by enlarging the dimple diameter and angle, and after carefully ream- ing and burring the rivet holes, cold dimples have been produced, but while these were satisfactory from a struc- tural point of view they were entirely unsatisfactory aerodynamically be- cause of the large dimple radius and the annular gap between rivet ana dimple. Experiments carried out by North American with the coin dimple, and by Northrop with the two-stage coin dimple, have produced satisfac- tory results, but these are limited to certain dimple sizes and gages. Since it was known that the duc- tility of 75S could be appreciably im- proved, without loss of strength, by limited heating, an effort was made to devise methods and equipment for hot forming the dimples. Frictional heating produced by a spinning tool was found to be impractical on ac- count of the time consumed, the bulkiness of the tooling, and the need for considerable skill on the part of the operator. Conduction heating was likewise rejected because it gen- erally requires a heating element which is a part of the punch or die, the time required is too great, there is danger of overheating with re- sultant annealing, and the high tem- perature (approximately 600°F) is a safety hazard. Resistance heating was found to be most satisfactory and to produce dimples far superior to the standard 24ST dimple. Fig. 9 shows the set up of the re- sistance heating dimpling equipment employed by Northrop, in which an ac spot welding transformer is used as a source of current. The current is fed to hardened beryllium copper, water cooled electrodes ‘into which the hardened tool steel punch and die are inserted. The lower electrode holder is raised above the bottoming ledge by a steel spring, so that when the dies are closed a positive contact is assured between the dies and the aluminum stock. When the spring is compressed % in., creating a pressure of approximately 85 lb, a switch is tripped, setting off the electronic timer which closes the circuit from '. the power supply to the transformer. The metal is heated almost instantly, THE IRON AGE, December 13, 1945—6! a a 7 4 be) * + ia = - ae = SAE “tr ae icicle onli lia ae lao lama a ie cate peti 0 sete posite nba sac trngpe ne Replaced ieee Ai dia lia, a ws ates cain initio gti tap Nites te acute apatites at aginst tn tt et i ee Cera “ SATO i pent nee eet, aint allan tad Tiacahth de Sirnctiiegneen nlaertntios and the upper die continues to de- scend until a sharp flush dimple is formed in the ductile metal. The heating current remains on for only a fraction of a second, and is inter- rupted before the dies open so as to avoid the possibility of arcing and 62—THE IRON AGE, December 13, 1945 1G, 8— Segrega- tion of constituent in 75ST Alclad re- vealed by Keller's etch at 200X. resultant pitting. The current passes first through the edge of the hole, then radially through the surrounding area (See fig. 10). The temperature is thus greatest at the edge of the hole where large stresses occur, and drops very rapidly outside the area 1G. 9—Resistance heating dim machine em by Northrop, using a spot welding tra er for cur- rent supply. where actual contact is made. This is an ideal distribution system since the greatest heat is afforded in the areas where the most severe forming takes place. Proper timing is important, since if the current is applied too soon are- ing may occur, and if too late, the dimple may be partly or fully cold formed and the material damaged. Different transformer and timer set- tings are required for each combina- tion of dimple size and sheet thick- ness, and these are supplied in chart form to the machine operators. Sheet to be dimpled should be free of oil, dirt, or paint, but no special cleaning or etching is required. Holes should be burred to prevent aluminum pick- up on tools but no special attention need be paid to hole dimensions or condition. Unfortunately, for the present, hot dimpling is limited to assemblies which can be brought to the resistance dimpling machine. This can be done with almost all exterior skin material, but stringers, frames, and other members which are fixed in permanent jigs must still be cold dimpled. Resistance dimples in 75S permit the making of riveted joints in which the seated rivet gives the appearance of a machine countersunk rivet joint, and so high are the bearing strengths that a demand has been created for a higher strength rivet to improve joint efficiency. Rivets made from 75ST wire may be developed to serve this need, but the method of upsetting the head is still open to speculation. Upsetting by resistance heating may, however, be a possible solution. Machining and Welding In both the W and T tempers 75S possesses excellent machinability. The zine intermetallie compound yppears to give the metal free mi g properties, and with the, use of tungsten carbide . tools, properly ground, a better finish may be ob- tained than on any other high strength wrought aluminum alloy. Less warp- age is encountered than in 24ST or 14ST, and tool life is appreciably greater. Fusion welding of 75S results in _a joint which is highly susceptible to corrosion, although heliarec welding will give good fusion, and subsequent solution and aging heat treatment wil! give the joint a strength approach- ing that of the parent material. The drawbacks of such heat treatment are warpage and weld brittleness, in ad- dition to poor corrosion re