The Iron Age 1945-07-12: Vol 156 Iss 2

President ond BAUR LEONARD General Monager HAYES Advertising JOHNSON, Service and Market Promotion Manager Executive Offices Chestnut and Séth Advertising Offices Regional Business Manegers Cleveland Guardian Bidg. 428 Pork RAYMOND XAY Angeles 2420 Ave. Owned and Published CHILTON COMPANY AND DIRECTORS GRIFFITHS TERHUNE BAUR WILLIAM BARBER, JOHN JULIAN CHASE HARRY CHARLES HEALE Member, Audit Bureau Member, Associated Basiness shed every Thursday. North America, South America and Possessions, Foreign, $15 year, Single Copy, cents. ° ° Gagyriqnt 1545, Sy Onitten Gempany AGE Vol. 156, No. Editorial Editor Reads the Ads Technical Articles Precision Founding Microscopy Lead-Bearing Steels and Irons Standardization Shackles Spray Setup Polishing Wheels and Color Code for Bar Stock Pressure Sensitive Control Furnace High-Strength Plastic Laminate Iron Ore Concentrated Flotation Methods Electropolishing Stainless Steel New Equipment Features News Assembly Line Washington West Coast Personals and Obituaries Dear This Industrial News Industry News and Markets Exgess Profits Tax Limit Reduced War Plant Leased Budd National Tube Speeds Tap Carbon Tests Bombs for Japan Canada Planning Postwar Willow Run Builds Last Liberator AAF Fighters Carry Autopilot Machine Tool Market Developments Nonferrous Metals News and Prices Iron and Steel Scrap News and Comparisons Prices Week and Year Finished and Semi-Finished Steel Prices Warehouse and Steel Iron and Steel Pipe and Tubing Prices Exceptions Steel Price Schedule Pig Iron and Coke Prices Bolts and Nut Stainless Steel and Ferroalloy Prices Index Advertisers July 12, 1945 238 102 104 106 110 How Ryerson Alloys Protect Your Production Every When your shipment Ryerson alloy steels arrives, complete test data comes with them—data that enables engineers and designers call for the physical properties listed, with confidence that they can secured—that furnishes heat treaters with guide sure, accurate results and provides detailed record for your purchasing executive. part the Ryerson Certified Steel Plan, this data developed from actual laboratory tests. addition mill tests for chemical analysis and physical characteristics, Ryerson subjects sam- ples from each alloy heat four end-quench hard- enability tests. From hardness readings the test samples interpret obtainable physical properties for various size rounds the as-quenched condition and when quenched and drawn 1000°, 1100° and 1200° This test data comes with alloys which Department Served are identified heat symbol well color marking. And make doubly certain that you get the right steel Ryerson checks against mixed ship- ments spark testing all alloys stock. Ryerson alloy service costs you nothing extra. protects your products and production. saves time and money. furnished Ryerson Steel-Service Plants, each located major in- dustrial area. The Ryerson alloy plan explained detail our booklet Hardenabil- ity”. you did not receive copy write today. And get touch with your nearest Ryerson plant when you need alloy steel from stock. JOSEPH RYERSON SON, INC. Steel- Service Plants: Chicago, Milwaukee, Detroit, St. Cincinnati, Cleveland, Pittsburgh, Philadelphia, Buffalo, New York, RYERSON STEEL ALLOY STEELS ALLEGHENY STAINLESS PLATES SHEETS STRIP STEEL STRUCTURALS TUBING PIPE MACHINERY 42—THE IRON AGE, July 12, 1945 TOOL STEEL SCREW STOCK BARS od j ; VAN and BAUR ond General 6 Stef HIGHT Editors WINTERS ALBIN JOHN ANTHONY BARMASEL MILLER DAVIS 428 Park POST HARDY hip- Cleveland 1016 Bidg BRAMS aves 7318 rson OSGOOD in- Worth Hale Sen Francisco ined 1355 Morket abil- ROBERT day. lant DEAN FRAZAR Boston teel- SHARP kee, Milwaukee Toronto, New RAYMOND Angeles St. BARS CHINERY Editor Reads the Ads man bites dog—that’s news.” This was the nugget wisdom bestowed upon young reporter experienced news editor who had rejected story based upon the situation reverse. Perhaps many will also news that editors read the advertise- ments their publications. Especially business paper editors. And most especially when they are far away from home. Take, for example, the case Bill Phair. Many you will remem- ber him having been Iron Age editor for number years before put Uncle Sam’s garments and became Seabee. They choose good men for that line work! Bill has been sojourning the South Pacific for the past two years more advance agent for the Marines. When the Marinés get set take island away from the Japs, the Seabees ahead make things comfortable for them. They follow the barrage make roads the landing beaches, scoop the debris and litter fallen trees— and dead Nips—so that our boys can get through the remaining live ones and otherwise make themselves extremely useful. Wherever Bill located will good job, for that the kind guy is. But the interesting part that reading the adver- tising your family journal from entirely new basis appreciation. (Once while copy gets through him). Undoubtedly formerly read the ads, most do; while was sitting his desk our New York office between trips. But one thing read about, let’s say, caterpillar tractor while enjoying peace and quiet, and still another thing read about just after you have taken dive from the driver’s seat into the jungle keep from becoming perforated. Maybe you will interested were some comments recent letter from Bill. think that there name that has been The Iron Age’s pages that hasn’t crossed path sometime another, and the thousand and one little items and design features intended make the equipment just little more effective than you’d expect. still feel though, that much our equipment designed too finely. The use 7/16 in. bolt for example, and half-inch another just doubles the maintenance problem. the other hand, remarkable how engine produced Detroit can shipped through all these climatic changes, stand open air storage for months and yet reaches well that hour’s time can have operating smoothly.” Lots other boys are having the same experience Bill seeing the old familiar advertised names action and helping win the war. seems that this going mean something the future when these chaps come home take their places industry! q | | | MUNZER - iit { 4 4 3 § 4 i ‘ 4 3 2 4 5 — Slag tests, far faster than chemical analyses, help Inland control the quality Even Slag Tells Control Story Inland Metallurgists Four more times during each open Inland, dispatches the result the hearth heat, slag samples many slag test back the open hearth. grades steel are taken, crushed, and dispatched, through network pneumatic tubes, the oratory. Within few minutes after Inland has turned progressive slag tests into one the most important and useful methods for continuous the receipt each sample, labora- control the process steelmaking tory technician, using special, fast open hearth furnaces. Inland Steel method for determining slag charac- Company, Dearborn St., Chicago teristics that has been highly developed Sales Offices: Cincinnati Detroit City Milwavkee New York St. Paul LAND @ = AD i - 7 { ia | j July 12, 1945 News Front The monthly ASF production rate has been revised downward per cent since February. According present plans production December 1946 will reduced per cent from the last full month production for war. Reports from Los Angeles state that Kaiser Co. will spend $1,495,700 Fontana and install equipment for rolling sheet 3/16 in. and thinner. Also setup will unit salvage blast furnace gas, mixing with gas and using fuel place oil. Natural trends the postwar period away from high cost production units will cause the Steel Corp.'s operations the East somewhat curtailed favor more economical units other districts. buying mission here representing number India's industries said been blocked from plant visitation continuing security restrictions. The Foreman's Association America, having established chapters steel plants since 1943, awaiting NLRB action establish collective bargaining plart Fort Worth. mentioned News Front some eight months ago, six steel plants. Most recent development the trend postwar industry diversification Pressed Steel Car Co.'s interest household appliances, heating and air equipment, and refrigeration. Virtually perfect combustion for industrial furnaces said obtained with automatic damper control unit operating furnace pressure than temperature. promising new laminated plastic, Conolon, stronger and lighter than aluminum resistant vibration and absorption moisture, has been developed craft manufacturer. Savings effected keeping buffing and polishing wheels cutting continuously had spraying mixture cold glue and abrasive. substantial saving furnace time after heat has been "blocked", with fre from scale, segregation and pipe, reported for novel carbon sampling effect some Steel Corp. plants. Last week's News Front report that Crucible Steel had shut down its electric furnaces the Pittsburgh district because lack orders was unfounded. The Midland Pa. plant steelworks was shut down for few days the holiday week becay repairs, holiday and some vacation absences. Operations Crucible Pittsbug are back per cent this week with electric furnaces operating. Since April the Army Air Force has made two aircraft procurement cuts, tota 43,792 airplanes and representing $7,590,000,000. Requirements for the current fig year are only one quarter number and considerably lower total weight than the fiscal year 1945 estimates. The airplanes for the Japanese war are primarily Navy types and are already order. Surprisingly the 1946 fiscal year estimates includes funds for only 600 propelled planes, which indicates less use this type craft than has been pro esied. However, once American troops get firm bases the Japanese home islands there will extensive utilization robot bombs and rockets, part] experimental basis. B-32 heavy bomber, running mate the stops production the Gov will occupy minor role prosecuting the air war. Ford went into 1946 model production only three days after WPB authorized new production, this speed being permitted large reserves nearly every part held the production line was shut down 1942. Ford's plans include eight complete lines, including three Fords, two three Lincolns. The Fords will include engine 100 hp, now one with six cylinder, engine; and new light Ford. Officials are for production rate 8000 units per day soon unlimited production autl ized. ster yses, the | “. Precision Founding FRANCIS DITTMAR Consulting Engineer, Metal Products Buffalo, Ina series nine articles, the author evaluates the features several precision founding methods that have been practiced both here and Europe. the casting simple ring central example, the economies and limitations each the methods will compared. this first article analysis the making wooden pattern," the first step the process arriving accurate master patterns trial and error. The second the making temporary glue molds, discussed the second article. ETAL castings made either the centrifugal the vacuum process are not par- ticularly recent. Neither the pour- ing molten metal into molds other than sand anything new. During the past century the practice Continental Europe, for instance, has been cast yellow brass, bronze and iron gypsum leavened with burnt clay, such brickdust. With the de- velopment asbestos, this material was preferred burnt clay; and later on, powdered quartz and other refractory materials came into use metals requiring tempera- tures above 2000 deg. However, burnt clay, French sand and also coarser mesh sands well other materials like nature are still being used, particularly the mak- ing “cradles” for iron and steel first the aim making castings this sort was not precision re- gard measurements; the accuracy desired was rather that fidelity reproduction. this type found- ing developed castings were made yellow brass, bronze and iron such sharp details and high degree finish that the work appears have been carved. Whether not the molds for these castings were stationary, spun subjected vacuum pressure for the moment immaterial. For that matter molds for cannon—bronze 46—THE IRON AGE, July 1945 iron—and for cast iron pipe were often spun, the molds being made sand bonded with either linseed oil molasses and baked—a process simi- lar present-day core making. Some decades ago piston rings for internal combustion engines were cast cen- trifugally bonded sand molds. one case the rings were in. di- will cast yellow brass from the try patterns. Ring must round and concentric within in. limits ameter with in. cross-section, and the castings were not turned bored but were ground finish their outside and inside diameters well their faces; hence these castings were held within close limits. Incidentally, the cores and molds for these rings were made core- boxes having slight draft. After baking, the molds were placed four flask, one atop the other, and 16-in. diameter central core was firmly fixed the cast iron flask con- taining the molds. The one-piece cy- lindrical flasks had the metal was poured into the air space between the outer wall the central core and the inner wall the mold. The flask was spun 800 r.p.m. and the gates leading into the mold were 1/16 in. high 5/32 in. wide. more detailed description circular castings, whether rings patterns arranged circle, will found subsequently Part VIII. precision founding one cannot afford expensive patterns the out- set; the master pattern eventually trial and error, crept down step waste trial patterns which are used only once because they are de- stroyed the process. because the number try patterns needed that their making swift and cheap methods and materials must taken advantage of; whether not such try patterns are first exact regard this stage low cost and speed are the main considerations. Suitability for Foundries And since this creeping-down master pattern dimensions ne- cessity slow, painstaking and often tedious, might argued with some degree justification that precision founding not suitable jebbing ° 3, Th | Sharp Note: These surfaces must edges with each tion, these mits. nolds core- After was con- the space mold. and were tterns found annot out- tually step are de- cheap taken ich try regard rtance. are foundry. There are, however, many instances when castings high de- gree accuracy and finish can made any foundry provided the customer prepared pay for such accuracy and finish. Such instances would those where neither cen- trifugal nor vacuum pressures are necessary deliver required specifi- cations and consequently try pat- terns would needed. The proce- dure making patterns for such work will found Part III, and further detailed information regard- ing molds for such castings Parts and VIII. view the increas- ing shortage skilled molders, job- bing foundries may find advan- tageous consider this type founding. Processes explained this work and some practice, especially the handling plaster—described Parts and enable al- most any foundry produce satis- factory castings economically. order gain comprehensive perspective the entire field pre- cision founding seems advisable deal first with the matter from the mass production point view. The master pattern, upon which mass production based, must its con- struction and dimensions compensate for number factors unpredictable the beginning each separate product. These factors are unpre- dictable because precision found- ing the patterns stand very close relationship the mold, much more than they sand founding. For one thing, the composition and con- struction the mold will vary with the size and particular with the gating each pattern. Then, there also the composition the metal considered, variable factor and depending, because shrinkages, upon the nature the alloy used. Another factor the heat the metal while pouring; still another, the centrifugal pressure that metal against the walls and sections the mold—a pressure, the way, greatly compensated for heavy castings the use cradles, will ex- plained Parts and There the venting which must concealed castings. all very well claim that plaster-base any other kind mold self-venting; such molds are self-venting only the case small castings such those produced dental laboratories jewelry factories—castings weighing more than few pounds even less. For unbroken schedule mass pro- duced precision castings any size all, positive venting necessary rejected castings are held Section A-A 2—Preliminary placing gates accomplish uniform distribution metal. The number gates are in- creased the event that the piece does not come out with sharp edges ing that increase casting speed does not produce the desired edge). minimum. Such positive although concealed venting will discussed Part IV. first glance this citation ob- stacles may seem discouraging be- cause the amount labor involved prior getting under way with pro- duction and also, possibly, because the cost materials and equipment. But precision founding most the 3—Central tapered pin attached gates (see Fig. 2). addition serving locating point when mak- ing the glue mold has important use when making the mold for the metal castings. This feature also discussed succeeding articles. labor cost lies setting up, and once production under way, there comparatively little more whereas sand founding the last casting costs much the first. .to materials and equipment—the for- mer can purchased directly from manufacturers great deal less than from supply houses, while most the equipment needed can readily made the premises long the foundry has some sort ma- chine shop attached. the purpose this article not merely show every detail connected with precision founding but also show how make most the needed apparatus— whenever this practicable course —and thus afford foundries oppor- tunity for individual requirements and preferments. Try Patterns making the try patterns for the ring shown Fig. may agreed beforehand that the method about explained not the only one means which the patterns can made, and that not, perhaps, the most economical way this particu- lar instance. But the method ex- plained presents specific mode procedure which, after under- stood, not only applicable but necessary other phases preci- sion founding. will observed that this ring has 3-in. outside diameter, 2%-in. inside diameter and in. wide. Its ances +0.02 in. which means, among other things, that the casting must have pretty Further, the ring round within the specific tolerances and these also govern the concentricity the ring inside and outside diameters. Still further, the edges this ring are not chamfered; its specifications for sharp edges. And lastly, the specifications demand flat, parallel surfaces both outer and inner di- ameters; there draft whatever the pattern. The material yel- low brass: per cent copper, zinc and lead—or thereabouts. Later these articles the ring will cast iron and steel; here yellow brass under consideration for rea- sons which will appear presently. order avoid confusion fea- tures this ring will henceforth identified follows: Its outer and inner diameters its outer and in- ner peripheries; its two sides its faces. Obviously such ring cannot very well cast sand mold. not only question finish and accu- THE IRON AGE, July 12, 1945—47 ll | / ' = ' 7 for wax drainage often FRANCIS DITTMAR Consulting Engineer, Metal Products Buffalo, Ina series nine articles, the author evaluates the features several precision founding methods that have been practiced both here and Europe. Utilizing the casting simple ring central example, the economies and limitations each the methods will compared. this first article analysis the making wooden the first step the process arriving accurate master patterns trial and error. The second the making temporary glue molds, discussed the second article. ETAL castings made either the centrifugal the vacuum process are not par- ticularly recent. Neither the pour- ing molten metal into molds other than sand anything new. During the past century the practice Continental Europe, for instance, has been cast yellow brass, bronze and iron gypsum leavened with burnt clay, such brickdust. With the de- velopment asbestos, this material was preferred burnt clay; and later on, powdered quartz and other refractory materials came into use casting metals requiring tempera- tures above 2000 deg. However, burnt clay, French sand and also coarser mesh sands well other materials like nature are still being used, particularly the mak- ing “cradles” for iron and steel first the aim making castings this sort was not precision re- gard measurements; the accuracy desired was rather that fidelity reproduction. this type found- ing developed castings were made yellow brass, bronze and iron such sharp details and high degree finish that the work appears have been carved. Whether not the molds for these castings were stationary, spun subjected vacuum pressure for the moment immaterial. For that matter molds for cannon—bronze 46—THE IRON AGE, July 12, 1945 iron—and for cast iron pipe were often spun, the molds being made sand bonded with either linseed oil molasses and baked—a process simi- lar present-day core making. Some decades ago piston rings for internal combustion engines were cast cen- trifugally bonded sand molds. one case the rings were in. di- will cast yellow brass from the try patterns. Sharp surfaces must edges with each other. Ring must round and concentric within Q002 in. limits ameter with in. cross-section, and the castings were not turned bored but were ground finish their outside and inside diameters well their faces; hence these castings were held within close limits. Incidentally, the cores and molds for these rings were made core- boxes having slight draft. After baking, the molds were placed four flask, one atop the other, and 16-in. diameter central core was firmly fixed the cast iron flask con- taining the molds. The one-piece cy- lindrical flasks had cover and the metal was poured into the air space between the outer wall the central core and the inner the mold. The flask was spun 800 r.p.m. and the gates leading into the mold were 1/16 in. high 5/32 in. wide. more detailed description circular castings, whether rings patterns arranged circle, will found subsequently Part VIII. precision founding one cannot afford expensive patterns the out- set; the master pattern eventually trial and error, crept down step waste trial patterns which are used only once because they are de- stroyed the process. because the number try patterns needed that their making swift and cheap methods and materials must taken advantage of; whether not such try patterns are first exact regard this stage low cost and speed are the main considerations. Suitability for Foundries And since this creeping-down master pattern dimensions ne- cessity slow, painstaking and often tedious, might argued with some degree justification that precision founding not suitable jebbing ° ° ° if j | SS | ction, these imits. molds core- After ind was con- cy- the space mold. and were le. rcular tterns found out- tually ict step are de- ecause needed cheap uch try regard rtance. are ne- often some recision jebbing foundry. There are, however, many instances when castings high de- gree accuracy and finish can made any foundry provided the customer prepared pay for such accuracy and finish. Such instances would those where neither cen- trifugal nor vacuum pressures are necessary deliver required specifi- cations and consequently try pat- terns would needed. The proce- dure making patterns for such work will found Part III, and further detailed information regard- ing molds for such castings Parts and VIII. view the increas- ing shortage skilled molders, job- bing foundries may find advan- tageous consider this type founding. Processes explained this work and some practice, especially the handling plaster—described Parts and enable al- most any foundry produce satis- factory castings economically. order gain comprehensive perspective the entire field pre- cision founding seems advisable deal first with the matter from the mass production point view. The master pattern, upon which mass production based, must its con- struction and dimensions compensate for number factors unpredictable the beginning each separate product. These factors are unpre- dictable because precision found- ing the patterns stand very close relationship the mold, much more than they sand founding. For one thing, the composition and con- struction the mold will vary with the size and particular with the gating each pattern. Then, there also the composition the metal considered, variable factor and depending, because shrinkages, upon the nature the alloy used. Another factor the heat the metal while pouring; still another, the centrifugal pressure that metal against the walls and sections the mold—a pressure, the way, greatly compensated for heavy castings the use cradles, will ex- plained Parts and There the venting which must concealed castings. all very well claim that plaster-base any other kind mold self-venting; such molds are self-venting only the case small castings such those produced dental laboratories jewelry factories—castings weighing more than few pounds even less. For unbroken schedule mass pro- duced precision castings any size all, positive venting necessary rejected castings are held this pornt Section A-A 2—Preliminary placing gates accomplish uniform distribution metal. The number gates are in- creased the event that the piece does not come out with sharp edges ing that increase casting speed does not produce the desired edge), minimum. Such positive although concealed venting will discussed Part IV. first glance this citation ob- stacles may seem discouraging be- cause the amount labor involved prior getting under way with pro- duction and also, possibly, because the cost materials and equipment. But precision founding most the 3—Central tapered pin attached gates (see Fig. 2). addition serving locating point when mak- ing the glue mold has important use when making the mold for the metal castings. This feature also discussed succeeding articles. for wax labor cost lies setting up, and once production under way, there comparatively little more whereas sand founding the last casting costs much the first. .to materials and equipment—the for- mer can purchased directly from manufacturers great deal less than from supply houses, while most the equipment needed can readily made the premises long the foundry has some sort ma- chine shop attached. the purpose this article not merely show every detail connected with precision founding but also show how make most the needed apparatus— whenever this practicable course —and thus afford foundries oppor- tunity for individual requirements and preferments. Try Patterns making the try patterns for the ring shown Fig. may agreed beforehand that the method about explained not the only one means which the patterns can made, and that not, perhaps, the most economical way this particu- lar instance. But the method ex- plained presents specific mode procedure which, after under- stood, not only applicable but necessary other phases preci- sion founding. will observed that this ring has 3-in. outside diameter, 2%-in. inside diameter and in. wide. Its ances +0.02 in. which means, among other things, that the casting must have pretty smooth skin. Further, the ring round within the specific tolerances and these also govern the concentricity the ring inside and outside diameters. Still further, the edges this ring are not chamfered; its specifications for sharp edges. And lastly, the specifications demand flat, parallel surfaces both outer and inner di- ameters; there draft whatever the pattern. The material yel- low brass: per cent copper, zinc and lead—or thereabouts. Later these articles the ring will cast iron and steel; here yellow brass under consideration for rea- sons which will appear presently. order avoid confusion fea- tures this ring will henceforth identified follows: Its outer and inner diameters its outer and in- ner peripheries; its two sides its faces. Obviously such ring cannot very well cast sand mold. not only question finish and accu- THE IRON AGE, July 12, — Small So ~~ 94%. / Gj 1 racy; the two flat sides and also, some degree, the sharp edges would make sand casting impossible. Conse- quently, this job one for centrifu- gal casting. Furthermore, because the flat, parallel sides and the sharp edges demanded the specifications will necessary use wax pat- tern. other words, this run- out job, made via the cire-perdu “lost-wax” process. Lost-Wax Aspects This lost-wax process, while not precisely feature pre- cision founding, would necessary the present case because straight-sided pattern could not gotten out plaster-base mold after that mold has set. Secondly, split mold cannot used because, be- sides being expensive make under mass production, such mold would also apt leave seams fins the casting and such fins are out the question because the tolerances specified. snagging can done these castings since snagging would destroy their accuracy. There will be, course, the gates contend with, but these can that what remains their traces can re- moved with file—just touch, that the file marks blend with the casting skin and will nowise inter- fere with the job’s accuracy. Should quantity warrant the ex- pense, shearing tool the punch and die order could used provided the castings have been poured plaster and asbestos mold: If, the other hand, the mold contained gritty refractory materials, such speedy method removing gates could not used. the utmost impor- tance give careful consideration every separate.step taken each new casting proposition. the present case, the first step would turn ring some hard- wood, being made about 3/32 in. big all over. That is, the ring would 3/32 in. big its outside diameter and 3/32 in. small its inner diame- ter and the 1-in. width would in- creased 1-3/32 in. This addition, 3/32 in., would just about take care shrinkages. Other difficulties that may appear would due mold construction and would not likely remediable with pattern adjustments, this being just plain ring. But view the high zine and, especially, lead content the metal used, some trouble may develop result insufficient, im- proper slow venting. the lat- ter factor, since metal enters spun mold very much faster than enters stationary one, let alone one that 48—THE IRON AGE, July 1945 made sand, only natural that air and gases must leave that mold almost instantaneously. already pointed out, molds used centrifugal and vacuum casting are self-venting only within limited range, hence extra, quick-acting vents must provided which will leave marks the castings. Such venting will gone into little later on. Gating The next step after the ring has been turned would making the gates. Ordinarily centrifugally cast ring 3-in. diameter, with cross- brass, should feed well through three gates, each in. thick and in. wide. These gates, shown Fig. are located the inner periphery and radiate from that surface toward the ring’s center. Each these three gates feed annular sec- tion wall in. thick, 1-in. high and about 2.6 in. long and therefore should evenly spaced dis- tribute uniformly the metal. shown Fig. the gates are fastened 1/32 in. inside one the two faces—which one does not matter since there draft the pattern. This done that the face nearest the gates can shaved off later, when reducing the width the ring master pattern size without inter- fering with the thickness the gates. The pattern with its three gates place will look like three-spoked wheel with its hub removed; the space that the hub occupied should about 1-in. diameter, and the gates radiating out from this center space must even length. For into that space between the gates there will now placed central. tapered pin in. long. Where this pin fits the gates will have %-in. long cylin- drical surface while the balance its length will tapered deg. (See Fig. 3.) This central hub pin serve locating point making the glue mold and will also have its when making the mold for the castings. Before going any further with this proposition would well con- sider the gating for moment longer. Adjusting for Distortion Supposing that the first trial cast- ing shows distortion, such bulging opposite the gates. Such bulging the outer periphery the ring would indicate too fast feeding and conse- quently the gates must reduced size. Such reduction should the thickness the where these join the inner periphery the ring and not their width. Should the next trial casting show distortion but have, for instance, dull edges—remember sharp edges are wanted—the feeding would too slow, all other things being equal. The metal did not get into the mold fast enough. The most immediate remedy for that would speed the mold which, for example, let assume has been spun 500 r.p.m. 700 r.p.m. might remedy that fault. But should the edges still after increase revolutions the gates should now reduced further size their entrance into the mold, both thickness and width, and three additional gates should added that there now are six small gates instead the three original big ones. matter fact, the more small gates there are, the better the casting obtained, and the only reason why one starts with few gates possible, even when these are big and leave compara- tively large marks the casting, that cheaper mass production. For one thing, fewer gates save metal, and for another, there less cleaning done each cast- ing. Obviously sound policy begin with few gates possible, and increase the number only when absolutely necessary, i.e., when all other remedies have failed produce satisfactory results; this fashion arriving point where there are just enough gates meet with the casting’s specifications. Referring the bulging mentioned above, such distortion not always due wrong gating the speed with which the mold spun. Faulty castings will also result from weak from too tight mold structure, from pouring metal either too hot too cold, from too high mild tem- pérature from one too low—all which will discussed Parts and From the finished wooden pattern, with gates and central hub place, all parts shellaced and smoothly sand- papered, the try patterns are made. Since couple dozen more might needed before the precise dimen- sions master pattern can ascertained these try patterns are made plaster. Should addi- tional gates needed these will also made plaster and glued onto the plaster try pattern means burnt shellac. The method ob- taining burnt shellac will dis- cussed Part ITI. make these try pat- ter pla an pot ma are offe mat fine and Alt ing amc port heat mos lets quir und Nat terns, each one exact duplicate the wooden one, completely mold into which the plaster poured. The simplest and cheapest way make that mold use horn glue. sure, there are the market themical com- pounds called “moulanges” and these may used with good results. These moulanges, however, require lower melting heat than does horn glue and are therefore little risky use be- cause plaster setting develops heat Microscopy ARIOUS investigators lead- bearing steels and irons have offered evidence support their con- clusions that most the lead these materials present the form finely dispersed particles lead and/or constituents containing lead. Although examination lead-bearing steels has failed detect inclusions which could identified with lead, radiographs lead-bear- ing steel ingots show segregation lead and microradiographs wrought lead-bearing steels indicate the pres- ence fine inclusions lead con- stituents containing appreciable amounts lead. has also been re- ported that when such steels are heated 752 deg. neutral at- mosphere, lead oozes and forms drop- lets the surface. this phe- nomenon that the basis the exudation test which steel re- quired pass before being accepted lead-bearing. Further work this subject was National Physical Laboratory, Ted- Description Material bearing carbon No. ingot lead- aring carbon steel. lead-free nickel-chroinium steel. in. nickel-chromium steel. Lead-free ingot iron Wrought Lead-bearing ingnt iron. Size and Location Samples No. ingot lead- Two specimens each steel and apt destroy the mold. For ordinary foundry work horn glue preferable not only because stands under little more heat—although not much more heat, will ex- plained when discussing plaster ing—but also inexpensive. easily procured from either retail hardware stores directly from meat packing houses. Horn glue can remelted indefinite number times without injury its properties. Such glue molds are good for thou- sands plaster casts; its length life depends great deal upon proper use and the care taken when idle. will reproduce any detail with absolute fidelity and flexible that drafts and undercuts are con- sequence. [Having evaluated the factors which make horn glue satisfactory molding material for try patterns, the author will discuss the second part this article the techniques the glue mold.] Lead-Bearing Steels and Irons dington, England, and presented the Committee the Heterogeneity Steel Ingots the British Iron and Steel Institute. Six materials were studied, four lead-bearing and Chemical analyses and other data these materials are given the ac- companying table. Sections the ingot were prepared for microscopic examination grinding progres- sively finer grades emery cloth and paper down the grade which was followed polishing rotating pad broadcloth charged with commercial grade fine alumina and lubricated with water. The surface was finished similar pad, using chromic oxide and water. Using this technique, all the lead- bearing materials showed inclusions having rough and mottled appear- ance, addition the inclusions normally present steels. The inclu- sions were sometimes free, but were frequently attached other inclu- sions. None these inclusions was seen the lead-free materials, but in- Details Materials Examined section ingot. from near rim 0.27 0.145) 0.032 and center mid-transverse 0.29 0.20 0.008 Specimen taken about in. 0.01 024 from top and near rim Chemical clusions similar appearance were observed lead-bearing 70-30 brass. confirmatory examination one the specimens another investigator revealéd inclusions similar form but lighter color than those obtained the author. Since seemed possible that the darker and mottled appear- ance the inclusions might caused their partial removal during pol- ishing, modified polishing technique was tried. The specimens were pol- velveteen hand directly from the stage, using specially pre- pared alumina and water made slightly alkaline adding few drops ammonia solution. Using nitric acid (specific gravity 140) excess crystalline potassinm indide. The excess iodide filtered off and the filtrate applied the polished surface the specimen for sec. The washed alcohol and dried hot air. and must not.be touched before examination. (CONCLUDED PAGE 130) 0.16 THE IRON AGE, July 12, D of de. en- pat- Standardization Shackles fatal accident resulting from the failure wire rope sling shackle the California Shipbuilding Corp. yard, Wilmington, led extensive investigation drop forged shackle quality and the drawing rigid specifications for inspection and test, out which hoped national will eventually developed. The investigation work Calship was carried under the supervi- sion Sverre Kongelbeck, then plant engineer. have, during the last few years, become frequent occurrences re- sulting loss life, personal injury and considerable material damage. One particular case occurring the California Shipbuilding Corp. was the cause investigation the shackle problem from the viewpoint safety. This occurred when stern frame assembly weigh- ing slightly more than tons drop- ped ft., killing worker and barely missing persons, besides causing extensive damage the hull under construction. This stern frame assembly had been properly rigged and shackle proper size had been selected evidently insuring safety factor relation the ultimate breaking strength the shackle generally listed manufacturers’ cat- alogs. This particular shackle was drop forged, anchor type screw pin shackle and examination the fractured parts showed that the shackle had been noticeably deformed prior failure. This observation led close examination the shackle material including complete chemical analysis clevis and pin material and deter- mination the physical properties from tensile-specimen cut from one the fragments. Micro- photographic analysis for structure and was also conducted well visual and exami- nation for evidence cold work other abuses during manufacture, cracks, seams, cold shuts ard forging defects. Suffice say that the forg- ing had been made 50—THE IRON AGE, July 12, 1945 steel bar stock. This type steel commonly called “free cutting” steel and has many useful applications, but not material suitable for forged shackles. This incident, which occurred over year ago, led the establishment thorough shackle inspection pro- gram embracing the testing all shackles issued the yard, all shackles warehouse stock well all new consignments shackles arriving the warehouse. Prior the inauguration the testing program, shackle failures were regular occurrences causing consider- able loss production, property and some instances loss life severe injury the workers. Not single shackle failure has occurred since the program was inaugurated. Since almost every commodity equal importance shackles gov- erned nationally recognized stand- dards, surprising find that the manufacture shackles has not been governed specifications other than incomplete and great extent faulty specifications, such Navy Specification 42-C-19 (Int.), men- tion one example. order achieve safety and economy became evident that steps should taken immediately cor- rect this condition and have set specifications drawn that would acceptable both manufacturers and users alike. part this program Calship’s plant engineer visited number manufacturers shackles who have been that business for half cen- tury more, well several ship- yards the East. the course these discussions, was brought out that accidents caused shackle fail- ures and difficulties obtaining shackles sound quality was means local Calship phenomena. Several opinions were verified: (1) all instances where bessemer steel bar stock has been used, for ex- ample, the resulting shackles were inferior quality and failed use loads far below what generally con- sidered “safe working load” for drop forged open hearth steel shackle the same size. sug- gested, therefore, that shackles allowed manufactured from bessemer steel. (2) The quality the bar stock should controlled per Federal Specification No. QQ-S-763a, para- graph 2C: “All material shall uniform quality and condition, free from pipes, seams, laps, cracks, slag, hard spots, porosity, slivers, scabs, rolled- excessive non-metallic in- clusions, segregation, and other de- fects that might detrimentally af- fect its suitability for the service intended.” (3) Preheating temperatures the forge shops cannot practically con- trolled other than judgment and the variable conditions the forge shop tends produce great varia- tion in, and often too high, preheating temperatures. seems that the only practical method obtaining uniform sound quality shackles normal- ize the finished forgings from con- trolled temperatures. (4) The slip eye bore only have sufficient tolerance over the pin diameter allow the pin concentric with the threaded eye bore. (5) The finished shackle should general pass inspection such currently carried out Calship. the past was the custom Calship purchase shackles stand-- | q i | ard out sati fact mer | | of | seve gen mar and ity that tion the thes ship cher mic shackle received from warehouse stock. failed approximately 2000 Shackle Pin ard hardware items from jobbers with- ‘out specifically asking that the lot satisfy certain minimum strength re- facture. result, one consign- ment there would quite variety one particular size shackle from several manufacturers, with great variations their physical properties. Inasmuch during the war emer- gency period several hundred new manufacturers were encouraged take the production shackles, and view the inconsistent qual- ity their products can assumed that there prevails substantial lack control and judgment the selec- tion raw materials well the manufacturing processes used these various suppliers. Investigations carried out Cal- ship included laboratory tests such chemical analysis the material; microphotographic examination The crack this shackle was not visible the start the proof load test. Upon proof loading, immediately opened and failed shown. Was not Magnofluxed prior proof loading. Proof Load Lb. Size, In. (First) Pin Size, In. Shackle (Revised) 14,700 the eye this new shackle were cause for rejection. These cracks were fairly deep. The shackle withstood proof loading. However, highly doubt- ful the shackle would satisfactory under impact loading fatigue. Corrosion inside the cracks would further wecken the shackle used production. Proof Load Lb. (First) (Revised) shackle was rejected visually because hot tears the slip eye the shackle. Shackle withstood proof loading satisfactorily, however. Shackle Pin Size, In. etched specimens for the determina- tion grain structure and grain size; Rockwell and Brinell hardness tests; and tensile tests for the determina- tion ultimate stresses, the yield stress, the elongation and reduction area. The shackles themselves have been subjected tensile tests or- der determine the ultimate strength, the deformation under load, well the establishment such proof test loads that would re- quired the inspection program order classify the shackle safe unsafe for standard working load and working condition. All shackles that were previously issued the yard were withdrawn and tested the established proof test load and the specimens which failed pass the test were scrapped. The balance the specimens were then subjected tests for indication invisible cracks that Proof Load Lb. (First) (Revised) 17,136 14,700 might have developed during the proof loading and also for possible defects developed during the manu- facture the shackles. Shackles fail- ing pass the tests were also discarded. New and used shackles warehouse stock were also exam- ined like manner, and new con- signments arriving the yard were subjected the same approval test- ing and inspection. Some the re- sults these tests are shown the accompanying illustrations. There may some objection the part vendors the acceptance rejected material, since they have not been notified this inspection sched- ule, nor have they guaranteed their products stand under such proof test load. This itself illus- trates great extent the need for standard specifications drawn that are acceptable both the ven- THE IRON AGE, July 12, * q ‘ - ° ° ° d q q q f q ma 4 4 . > shackle pin was new shackle and under proof HIS used shackle shows cracking both longitudinal and transverse shackle clevis. Rejected Magnaflux. Shackle Pin Size, In. loading pin deformed. The pin also shows reduction area the screw threads; therefore, consequent notch effect between the bearing part the pin and the threads. The slip eye diameter was too large compared the pin diameter. pin shown. Shackle Pin Size, In. (First) 17,136 dors and the users. matters stoed the spring 1945, Calship was rejecting unfit for use between and per cent the total shackles purchased. These rejected shackles are returned against the vendor. very large percentage the shackles initially the yard the inception the test- ing and inspection program failed meet safety requirements and were scrapped. Types Shackles Shackles used the Calship yard are all the screw pin, anchor type, drop forged steel shackles. The chem- ical analysis the material cur- rently supplied varies widely from vendor vendor and several cases inconsistencies serious nature have been noted shackles taken from individual consignment. the Calship’s belief that unless shackle material specified fall with- certain limits chemical composi- tion and specified maximum preheat temperatures for drop forging and subsequent minimum normalizing temperature, there will consis- tency quality the shackles brought into the yard and the testing program becomes difficult and expen- sive. always well ask oneself what the criterion the desired Calship is-concerned the answer this question regarding shackles would follows: The shackle should neither too hard nor too soft. The degree hardness should controlled allow proof test load least twice the safe working load 52—THE IRON AGE, July 12, 1945 Bending occurred the screw end part the Proof Load Lb. (Revised) 14,700 applied the shackle without permanently deforming the shackle such extent that the pin binds degree that removal hand becomes impossible. the same time, however, degree ductility desired order that the shackle, case extreme overloading, will deform considerably before fracture order warn the operators the condition. believed Calship that such shackle can very readily manu- factured from medium carbon steel bar stock the following analysis ranges: 0.35 per cent —0.50 0.90 per cent without increasing the manufacturing cost noticeably the normalizing heat treatment, and the same time maintaining the ultimate strengths listed the leading manufacturers. When selecting shackle for particular purpose, the given ultimate breaking strengths are taken for granted and knowing the load the called safety factor selected rela- tion this ultimate breaking strength and this basis certain size shackle selected. The reliability the figure given ultimate breaking strength never questioned. Inasmuch the shackles are manu- factured variety methods and from wide range type steels, obvious that uni