The Iron Age 1930-03-06: Vol 125 Iss 10

EIRO NAGE New York, March ESTABLISHED 1855 VOL. 125, No. Condition Material Watched Closely Ball Bearing Manufacture involves not only very accurate workmanship, but also close control materials assure uniform hard- and homogeneity structure the finished product. And, both these must obtained under mass production conditions. ball bearings, close accuracy balls and races assures even dis- tribution the load, while uniform hardness and sound structure material maintains the properly distributed loading initially secured accurate workmanship. that the manufacture such bearings frequent inspection dimensional accuracy, form and finish must paralleled more less extensive system mate- rial tests strategic points before and after heat treat- ment, the Hartford plant the Industries, Inc., these material tests begin with the receipt the bars, tubes and other raw material, and are made various stages manufacture, the final assembly. Except for chemical tests and examinations under the microscope, these inspections are for the most part means hard- ness tests. addition, magnetic test each piece for homogeneity structure made immediately after hard- ening. The larger part the output self-alining ball bear- ings ranging from in. outside diameter. Smaller and larger ball bearings are also produced, well cylindrica] roller and special bearings. this plant also made, separate shop, ball-bearing drop and post hangers and split and solid pillow blocks. The balls are received ready for assembly from the company’s Atlas Ball Co. plant Philadelphia, that the making races, cages and rollers and assembling the parts into finished bearings are the main activities this plant. Material Inspected Before Being Admitted the Shop Races for bearings in. are made from steel similar 52100 and having 0.95-1.05 per cent car- bon, 1.40-1.65 per cent chromium and 0.25-0.40 per cent manganese, with sulphur 0.020 and phosphorus 0.025 per cent. The chromium and carbon contents cause mum penetration the effect heat treatment and de- velop high degree hardness. Rolled bars and seamless tubes are used for the races bearings in. out- side diameter, and forgings special composition are used for larger bearings. sample every heat steel received, and some cases samples every bar and tube particular heat, tested chemically. Then before being admitted the first production department, which may several days weeks later, each bar and tube undergoes another test. sample sawed from each end the bar tube, and both the bar and samples given identification number. One sample goes directly the laboratory for Brinell test; the other sent the hardening room and later for- warded the laboratory for examination under the micro- scope—porosity, segregation, slag and other defects being looked for. Until approved the laboratory the steel not admitted the manufacturing department. Bars and tubes which show surface defects are given light surface cut bar lathe determine depth defects. Automatic Lathe Department The first race manufacturing unit the automatic lathe department, the races receiving their initial ma- chining Acme and Gridley automatics. The inner and outer race made from the same bar, and operations in- clude turning the outside diameter, drilling the center hole, trepanning, and forming the ball groove the outside the inner race. “Sphering” the outer race done special machines. Before proceeding through the shop all races are marked means steel stamps carried punch presses. Large rings are turned, grooved, faced and chamfered and 24-in. Fay automatics. Having been rough and finish turned ‘and formed, the races are inspected for size and visually for condition material. They then proceed straight ,line the hardening room, the point major control the ma- terials. Hardening Room Equipped With New Furnaces This hardening room, recently reequipped, contains three gas-fired continuous furnaces having automatic tem- perature and mechanical control, and provided through- out with recording pyrometers. The furnaces are built brick, suitably incased and have the gas burners located along the sides. One them ft. long and ft. wide and provided with alloy steel shaker hearth, which in. wide and has flanges the side keep the work line. the charg- —— 930 } } “ 4 i q a 703 ing end there ft. long loading table. The hearth moved forward high and returned low velocity means cam, the rate movement being adjustable suit the needs the work being treated. The work preheated the forward end the furnace. The steel parts are heated 1480-1560 deg. Fahr., accord- ing physical properties desired. Drawn 350 deg. Fahr., the Brinell hardness the steel about 650. steel chute extends from the discharge end the furnace into quenching tank. This tank, ft. long, ft. high and ft. deep, equipped with conveyor which carries the work through the oil quenching medium and finally elevates another conveyor which connects with washing machine. The oil the tank kept tated means motor-driven propeller. The two other furnaces are similar construction, but larger, one them being ft. long and the other ft. long, both them ft. wide. feature these the hearth, which consists series alloy-steel rollers set close together and driven from the outside the furnace sides means chain and sprockets. The rolls thus individually revolved pass the work through the furnace. Provision made for regulating the rate roller rotation, and therefore the heating time-interval, suit the particular requirements the work being treated. Quenching Tanks Equipped with Fire Extinguishers Conveyor-equipped quenching tanks also adjoin these furnaces. Quenching oil temperature held automatically about 110 deg. Fahr. means pipe coils within the tanks. When the oil too warm, cold water circulating through the tanks brings down the temperature; when the oil too cool, the flow cold water cut off automati- cally. Fire extinguishing apparatus the form chemical blanketing spray that released automatically through the melting fusible links provided for all ARGE Automatic Lathes Make the First Race Production Unit. The steel care- fully inspected before being admitted this department 704—The Iron Age, March 1930 quenching tanks. This fire extinguishing chemical con- tained receptacle above each tank and sprayed through nozzles located along the sides the tanks. From the quenching tanks, the parts are conveyed the washing machine, also continuous type, which re- moves loose scale and quenching oil, the washed races and other parts dropping out into basket which later placed Leeds Northrup Homo tempering furnace. There are two these furnaces, one for low temperature work, the other for high temperature; the latter used for high- speed steel, when necessary, well for the low tem- perature work. carburizing done except special work. Having been heat-treated, the rings races the sand blasting room, which equipped with two large rotary outfits and, for thin rings, one table-type sand blast. Here, well elsewhere the works, good plant house- keeping, meaning cleanliness and good order, note- worthy. Die cast brass and bronze retainers are sand blasted improve finish. They are then pickled the same depart- ment remove sand from the pockets. Tool Hardening Room Adjoining the hardening room there the blacksmith shop and tool hardening room, which equipped with number small furnaces and carburizing furnace, all which are gas fired and have automatic temperature control. One furnace this battery has three heating chambers, one above the other. From burner the lower chamber, heat “ported” the upper chambers such manner that with the lower chamber heated 2400 deg., the upper chambers will maintained 1600 and 1100 deg., respectively. Thus work may preheated the middle chamber, heated for quenching the lower, and drawn after quenching the upper chamber. Immediately after hardening, washing and sand blast- | ing, the parts inspection bench where they are tested for hardness and for structure special mag- netic tester, which one the outstanding pieces special testing equipment the plant. This instrument calibrated “master” races known hardness and structure. should noted that the various hardness tests—Brinell, Rockwell and Sclere- scope—made different parts the factory during pro- duction serve check one another. From these tests, the hardened and tempered races the grinding department, which, might expected, well equipped for rapid roughing and for highly accu- rate finishing operations. Equipment includes Blanchard surface grinders, semi and full-automatic, for grinding the width, the work being held magnetic chucks. The work taken from these machines belt conveyors wash- ing machines that remove the grinding sludge, being demagnetized before entering the washer. The races are then tested for size automatic width height testers which represent another ingenious labor- saving production testing unit recently developed this plant. this point the rings are given another hardness test means Sclerescope arranged for rapid opera- tion. Adjoining this department there battery center- less grinders for rings all sizes except some the largest, and also center type grinders for larger rings ground arbors. There are also special semi-automatic bore grinding machines and special machines for grinding the grooves PECIAL Machines Have Been Devised Facilitate Grinding the Grooves the Inner Race. common with other de- partments the plant, careful attention has been given proper illumination the inner race. The sphere the outer race small ball bearings also ground special machines, the operator tending one rough and one finish grinder, both machines being equipped for automatic gaging. Bores are tested with flat solid plugs not being used. All grinding machines are equipped with size gages, some which are integral with the grinders. Although finish grinding gives excellent surface, the inner and outer races are polished remove grinding marks and give maximum finish. visual inspection made after polishing assure elimination all grinding marks. Both before and after polishing the rings are checked for size. this point there special check the grooves being square with the bore and parallel with the sides, and optical inspection for the purpose locating surface flaws and grinding defects. With the above operations completed, the races are taken the parts stock room, withdrawn order for assembly. Rejected parts each department, well finished bearings, are recorded the inspectors, and re- ported the factory manager each day. These reports set forth the specific shortcomings each piece. Rejec- tions due defective material are taken with the metal- lurgical department; those due defective grinding are referred the head the grinding department, the factory manager discussing the cause the defective parts with department heads each day. However, the con- ditions responsible for the rejections are usually rectified The Iron Age, March, 7 7 long before the department head called account, word being passed the department head the inspectors soon the spoiled parts make their appearance. Ball bearings are assembled one department, while thrust and roller bearings are made another, both drawing the central parts stock room. Although unique special equipment has been devised facilitate assem- bling these bearings, the process requires skill, and oper- ators are carefully selected and trained for this job. After assembly the bearing given final inspection, the bore, outside diameter and other dimensions being Although the precision nature such bearings would seem widely appreciated, either ignorance gross carelessness handling mounting reflected many the “disabled” bearings that pass through the Returned Goods Department. Entrance dirt and grit within the bearing, the foreign matter being ground between the balls and prematurely wearing out the races, perhaps the most common cause failure. The unwrapping bear- ings and leaving them upon bench exposed dirt and grit for hours, placing bearings upon dirty bench table from which they pick all sorts foreign mat- 4 Sphere Grinding Department the Hartford Plant the S.K.F. Industries. The sphere the outer race small ball bearings ground special machines equipped for automatic gaging checked. noted that the assembled precision ball bearing required from 0.0002 0.0005 in. all significant dimensions. Every bearing put arbor and given running test, well being checked for concentricity, and parallelism face and rings. This department uses Prestometer fluid gages and other types gages, for the most part special. Returned Goods Department Inspects All Parts Bearings order keep the stock parts and finished bear- ings unvitiated—that is, known accuracy and condition special department has been established receive all bearings returned from users because alleged deficien- cies, wrong size, etc. Whatever the reason for return, all parts such bearings are examined and reported before being sent stock, salvaged scrapped. This department, although very small, important Age, March 1930 ter, are not rare practices. Equally common, perhaps, the failure protect the bearings cover clean paper cloth when closing the assembly must deferred. Dirty grease from the hands workmen sometimes source trouble also. And there are errors fit. Too loose fit permits harmful peening action between the bearing bore and the shaft; too tight fit expands the inner rings and destroys the necessary clearance between the balls and races. Hand scraping the bearing seats (producing out-of-roundness) instead boring, reaming grinding the seat size, harmful practice met with. Putting anti-friction bear- ing worn shaft, resulting too loose fit, and shim- ming the housing instead boring receive bushing, are among other abuses that shorten the life such bear- ings and bring naught the careful manufacture and con- stant inspection outlined this article. j) 7 7 Mill Rolls Large Aluminum Shapes Alloying, Heat Treatment and Aging Gives Material Physical Properties Comparable with Those Mild Steel—Channels Rolled In. LUMINUM, the popular mind, associated with kitchen utensils, light cast- ings and architectural decora- tion. Known chiefly for its uses small ways and being soft, light weight and com- paratively high price, this metal has not been commonly competitor rolled steel heavy construction work. Yet aluminum has now definitely entered the lists construction material, not merely for special applications such aircraft fabrication, but fields which steel has been unchallenged, such the building railroad cars, ships, automobiles and machin- ery. aluminum structural mill rolling channels in., well other shapes and flats, squares and rounds, was put into service the-Aluminum Co. America Massena, Y., November, 1929. alloy- ing the aluminum, heat treating and aging it, material produced that has physical properties comparable with those mild steel. The shapes are recommended partic- ularly for uses where saving dead weight impor- tant. For example, the use aluminum alloy structural members railroad cars reduces the amount power required haul them. The lighter weight the metal also tends offset the higher cost compared with steel. The specific gravity aluminum alloy about one- third that steel, but compensate for much lower elasticity given shape the non-ferrous metal must have greater thickness. this account the net saving weight reduced about one-half. The new Massena plant L-shaped group struc- tures, containing 70,000 sq. ft. floor space. includes remelting and ingot casting unit, blooming mill and finishing mill. The structural mill, with its auxiliary equipment, occupies single building 900 ft. Pig aluminum melted four coke-fired furnaces. Coke brought into the building hopper cars and dis- charged into conveyor which elevates overhead hopper. Hatches the bottom the hopper are opened hand levers draw coke into buggies spotted below. The buggies are rolled the firing doors. Ingot Molds Heated Before Receiving Metal The furnaces have capacity for melting 20,000 lb. pig aluminum. The melting temperature controlled pyrometric equipment with indicating meters, furnished the Wilson-Maeulen Co., New York. Ingot molds must heated the same temperature before they receive the molten metal. The alloying elements are introduced into the furnace and are not added the ladle. Three different sizes ingots are made, one in. and weighing 2200 and large slab type, in., weighing 3000 Ib. These are the largest alumi- num rolling ingots ever cast. The smallest ingot molds are heated row five pits. The fuel crude oil, burnt under air pressure, and temperature control pyrometers. monorail used bring ladles the pits. Extreme care exercised avoid oxidation. The heated ingot mold raised the top the pit and the metal poured slowly, with min- imum agitation, into chalice feeding tube extending the bottom the mold cavity. added precaution deoxidizing flux added. The pouring temperature inserting Pyod temperature indicator into the molten metal the mold. Controlled Freezing Prevents Formation Pipe regulating the temperature the pits the freezing the ingots controlled, the gases the aluminum being released gradually and the formation pipe being prevented. Freezing takes hour hour and half. The control the freezing obtained slowly lowering the mold from the upper levels the pit where the oil burners are located into zone water sprays. The low- ering substantially automatic. The mold suspended cable which carried over vertical hydraulic appa- ratus arranged release the cable the predetermined rate that will bring the entire mold finally the right time totally within the water cooled bottom the pit. Two other mold-heating furnaces have been provided, one for bathtub ingot molds and the other for ingot molds. These molds are heated min. prior pouring. remove hot mold the top the furnace removed and crane hooks are lowered and fitted ears projecting from the mold walls. The mold then placed pouring posi- tion buggy pit close the melting furnaces. Pouring slow, and after the mold filled dross skimmed off. cable, actuated lever within con- venient reach the pouring position, pulls the buggy short distance from the furnace into freezing pit. This unit also fired the upper reaches crude oil under air pressure, while water sprays are forced against the mold the lower levels, controlled freezing being ob- tained manner like that described for the smaller molds. The melting room commanded 7%-ton Alliance overhead electric crane. The removal ingots the adjoining blooming mill building electric lift truck. For conditioning ingots, corresponding the chipping billets steel mill, large Betts boring mill has been provided. Cincinnati double grinder dresses blooms and billets. bay adjoining this equipment are two large roll lathes. The company has its own roll designers and roll turners and its own guide designers and guide turners. Alliance overhead electric crane commands the dressing equipment and the ingot storage and pre- heating department. 50-ton overhead crane, also The Iron Age, March 1930—707 q 4 { | { : Alliance, serves the roll lathes, the blooming mill stand and the motor room. Ingots Heated Electric Soaking Pits Ingots are taken from storage and inserted Swin- dell electric preheating furnace with pits. The battery requires 3000 kw. Pyrometric and control equipment gallery above. The temperature each pit taken several points, indicating and recording pyrometers giving continuous record. battery automatic temper- ature regulators controls the pit temperatures within any — L : d 4 “7 The Blooming Mill the Largest Aluminum Rolling Mill the World desired range. Beneath the operating platform the furnace are electrical contactors that turn the power and off each pit. Control temperature within accuracy deg. Fahr. The roofs the pits are lifted off Brosius 4-ton electric traveling crane. The 744-ton Alliance crane removes the ingots, which are heated temperature 850 950 deg. Fahr., and delivers them the blooming mill proach table. Largest Aluminum Rolling Mill the World The blooming mill, built the Mesta Machine Co., West Homestead, Pa., the largest aluminum rolling mill the world, having 38-in. diameter 84-in. face rolls. Various types rolls are used. While the writer was in. billet. Plates and slabs are also rolled, sheet slabs 708—The Age, March 1930 being rolled down and in., widths ranging from in., with maximum length 230 in. The mill has direct electrical drive and served hydraulically operated manipulators. Controls are cen- tralized pulpit above the approach table directly front the mill, two men handling all operations. The mill motor 5000-hp. direct-current, variable- speed reversing unit. Power supplied the mill motor motor generating set consisting 6600-volt alter- nating-current, 4000-hp. induction motor directly connected with two direct current generators. ft. diameter and weighing 70,000 mounted the motor shaft. The motor operates 520 r.p.m. and the rim the flywheel travels 26,000 ft. per minute. The wheel, which construction withstand the great strains set the high peripheral speed, acts balance between the motor and generators the motor generator set and takes care the large fluctuations current required operating the mill motor. The Allis- Chalmers Mfg. Co., Milwaukee, supplied the motor and the motor generating set. Mill Scale Produced Rolling The spindle speed the blooming mill 150 r.p.m. Reversing from 150 r.p.m. takes only sec. light lubricating oil flushed over the mill rolls during opera- tions, lubricant rather than coolant. contrast with the rolling steel, the rolling aluminum alloy produces mill scale. Billets are delivered roller table Mesta hydraulic shear, which has electrically operated depressing and push off tables and electrically operated gage for measuring the length cut. Lengths are sheared 220 in. Sheared billets are inspected and then hoisted Alliance over- head crane and conveyed Fairbanks track scale for weighing. Material rolled down into shapes moved narrow-gage railroad cars. Other forms semi-fin- ished metal are loaded for shipment other rolling units adjacent buildings plants the company other cities. Sheet bars, for example, are shipped the com- pany’s sheet mill Edgewater, Structural Mill Has Four Stands the structural mill building semi-finished metal passed through pusher type oil-heated reheating furnace. Material carried through the discharge side con- veyor, being deposited roller table connected with the first stand the structural mill. There are four stands, the first three being three-high with rolls in. diam- eter 60-in. face and the last being two-high with 48-in. rolls. Tilting and trailer tables, mounted transfer tables, serve all four stands. The mill was built the Mackintosh-Hemphill Co., Pittsburgh, and driven 2000-hp., 600-volt, direct- current, variable-speed motor. Direct current, this case also, obtained from motor generator set. The spindle speed the mill 100 r.p.m. unusual feature the operations that the fin- ished shape issues from the last stand momen- tarily held down the table rollers stick held workman. contrast with steel, aluminum alloy light that this precaution were not taken the structural shape might not respond the traction the rollers. From the mill the finished material goes Ryerson high speed friction saw and United Engineering gag press. This equipment used for material that does not require heat treatment. The gag press used also straighten shapes treated that might too crooked pass through the heat-treating furnace. After passing saw and press the material delivered hot bed. Material treated moved across the bed, which | a i aS Three ? igh = Structural Mill Has Four Stands Three-High and One Two-H £ | (to quenched, The quenched shapes are passed hear erving ler table Long Electric Furnace. They are then after which they are carried across transfer (at extreme left) through high-pressure water sprays the left the furnace) rol passing transfer the gag press (middle foreground), TRUCTURAL Shapes Are Heat Treated The Iron Age, March 7 § consists I-beams with top layers wood, carrier ft. long. The carrier, which driven continuous chain belt, conveys the shapes into the heat-treating unit. Shapes Heat Treated and Quenched The furnace, which more than ft. inside length, was built the Electric Furnace Co., Salem, Ohio. The heating elements are the cast grid metallic resistor type. Lift fingers pick the stock from the carrier and move the discharge table the opposite side the furnace. Uniformity temperature maintained throughout the working area. The furnace divided into zones, and the temperature each separately controlled automatic temperature regulator and indicated and re- corded pyrometric equipment. temperature differ- ential deg. Fahr. maintained throughout the working area the furnace. After being heat treated, each piece automatically quenched, being carried motor-driven roller table through high-pressure water sprays. The piece then passed transfer roller table adjacent the fur- nace, where straightened United Engineering gag press. then passed back alongside the furnace and moved across another transfer table roller con- veyor serving Ryerson friction saw, where cut length. From the saw passes line rollers scale, where the weighing done. Freight cars can run alongside that material can loaded overhead crane for shipment, warehouse, just being completed, adjoins the end the structural mill building and has capacity four cars. Oven Provided for Artificial Aging Certain high-strength alloys must aged higher than room temperature. For this purpose aging oven, which can receive shapes ft. length, has been provided. Structural shapes are handled and out the oven specially constructed, standard-gage railroad-type cars. The metal aged under steam, which circulated evenly throughout the oven electric fans. Recording thermometers permit close control the temperature. The structural mill commanded 10-ton Alliance overhead traveling crane built high-strength aluminum plates and angles, riveted. Load tests the crane indi- cate that compares favorably strength and rigidity with similar crane fabricated from steel, but with saving 24,000 Ib. Typical sections seen the writer the structural mill 10-in. ship channels, 8-in. structural channels, 4-in. angles, 3%-in. angles and 4-in. Z-bars. The mill also rolls flats in. wide and from in. thick, and rounds in. diameter. The web and leg thicknesses the shapes rolled vary according the specifications customers. Shapes Rolled Mainly from Three Alloys tructural shapes are rolled largely from three alloys: 17-S, 25-S and 51-S. The first two are copper alloys, containing per cent copper, 0.5 per cent manganese and 0.5 per cent magnesium and 25-S containing 4.5 per cent copper, 0.8 per cent silicon and 0.8 per cent manganese. The designation 51-S for metal that almost pure aluminum, containing only 0.6 per cent magnesium and 0.1 per cent silicon. The copper alloys when cast contain hard, brittle compound—Cu the form network. This com- pound contains per cent copper and surrounds the alu- minum-rich dendrites. Rolling breaks down this network and heat treating puts into solution. Quenching holds the solution. Heat treating very near the 710—The Age, March 1930 eutectic temperature, which the case alloy containing 5.65 per cent copper 1020 deg. Fahr. Advantages Solution Heat Treatment and Aging The solution heat treatment described follows: (1) Heating the alloy the proper temperature for sufficient length time bring about the solution the soluble constituents, and (2) quenching the alloy after the solution has been effected order hold the constituents solid solution. this treatment the yield point, tensile strength, hardness and elongation may increased materially. The next step, aging precipitation heat treatment, described low temperature treatment precipitate form the soluble constituents which are solid solution result heat treatment. The aging may take place room temperature higher tempera- ture. the latter cases termed “artificial” aging. This type treatment provided for the aging oven. Care must taken that the temperatures employed are not high enough place the alloy the annealing range. such case the effect the solution heat treatment would lost. Temperatures the oven are held 212 deg. 347 deg. Fahr. for various periods time. The precipitation treatment further increases the yield point, tensile strength and hardness the alloy but the sacrifice sometimes elongation. How Heat Treatment Affects Physical Properties The alloy 17-S, when annealed, has yield point 10,000 ultimate strength 26,000 elongation per cent and Brinell hardness 45. When fully tem- pered (aged) the same alloy has yield point 35,000 cent and Brinell hardness 100. The alloy 25-S, when annealed, has the following prop- erties: Yield point, 10,000 ultimate strength, 26,000 lb.; elongation, per cent, and Brinell hardness, 45. When fully tempered, 25-S has the following proper- ties: Yield point, 35,000 ultimate strength, 58,000 elongation, per cent, and Brinell hardness, 100. The alloy 51-S, when annealed, has properties fol- lows: Yield point, 5500 ultimate strength, 16,000 elongation, per cent, and Brinell hardness, 28. When fully heat treated, 51-S has the following proper- ties: Yield point, 35,000 ultimate strength, 48,000 elongation, per cent, and Brinell hardness, 95. All these are typical values, rather than guaran- teed. Alumina Reduced Electrolysis The location the Massena plant was determined the availability water power. power canal connects the St. Lawrence River with the Grasse River and the falls the junction generates 75,000 hp. electrical energy. About 60,000 hp. additional bought from Cana- dian plants. The electricity used reduce alumina electrolysis aluminum. bauxite treated Massena, all the ore used the Aluminum Co. America being chemically reduced alumina East St. Louis, Alumina reduced introduced into iron pot lined with carbon, which constitutes the cathode. Cryolite, obtained from Greenland, added serve the electro- lyte solution agent and carbon anode then lowered into the solution. About 0.8 lb. the carbon anode consumed for aluminum made. The power con- sumption produce pound aluminum approxi- mately hphr. 7 r= — Steel Castings Green Sand Care Needed Mixing the Sand and Gating the Mold —Venting, Feeding Heads and Pouring Carefully Considered PAUL RAMP* sand molds, which will stand under pressure and reasonably free from pin holes, blow-holes, sand holes and shrinkage cracks, several things must care- fully considered: character sand used; facing sand mix- ture; mixing and care the heap sand; pattern making, venting, gating, size and location feeding heads; use gaggers and rods and the method pouring. The sand should similar Ottawa silica sand, New Jersey silica sand. should coarse enough allow the gas escape from the mold freely, and with silica content not under per cent. produce sound, smooth steel castings green Facing mixture for green sand work may made Silica sand (without natural bond)....... 500 Ib. This facing must used next the pattern and around the gates. The moisture the facing must from per cent. mix the facing properly, place the silica sand and the correct percentage bentonite the mixer first and mix them thoroughly. Add the re- quired amount corn binder and mix min. before add- ing water. After the water added mix another min. When the sand ready removed from the mixer take moisture test. the moisture over per cent add more dry sand and remix. the moisture below per cent add water and remix. The moisture content very important and must not neglected any time. When facing ready for use must loaded into bin box and covered, prevent from drying out. *Recently superintendent foundry and pattern shop, New- port News Shipbuilding Dry Dock Co., Newport News, Va. Fig. 1—Gating for Mold Y-Connection, with Basin Downgate Gates Proper Facing under per cent moisture very hard work, because crumbles under the tools. Use in. facing sand patterns and around gates. Heap Sand Characteristics Heap sand consists used burnt facing sand. Hence, start green sand heap, all the sand must first facing sand. Heap sands containing percentage nat- ural bond sand must not used, want get the best results. The heap sand must mixed carefully the facing sand. When the green sand molds are poured and shaken out all the sand must carried the mixer and milled for min. after all the lumps have been crushed. Corn every 500 lb. sand. When the binder and the heap sand have been thoroughly mixed, water must added until moisture not over per cent has been secured. The moisture must determined before the heap sand re- moved from the mixer. Heap sand should used soon mixed, have the proper moisture. desirable have the moisture higher the facing sand than the heap sand, because damper facing will produce better surface the mold. too dry will crumble under the tool and cannot properly finished. desirable have the heap sand with lower per- centage moisture than the facing sand, because, when this the case, the surface the mold dries quickly, which what necessary. But the heap sand has higher moisture content than the facing sand, the surface the mold will not dry readily account the Fig. 2—Gate Arrangement for Globe Valve Mold. Letters have the same meanings Fig. The Iron Age, March 1930—711 ¥ higher moisture the heap sand behind it. such cases there always danger cut scab rough surface the castings, sand holes. The moisture should never guessed at. All patterns should have smooth surface and several coats good shellac, because green sand facing clings any rough surface the pattern and produces rough places and surface that will not peel when the casting taken out the sand. true the rough places pro- duced the rough pattern can slicked smooth with the tool. But, with facing this character, the surface repaired with the tool will not peel nor produce casting smooth the surface that properly rammed and does not require any slicking. For this reason, smooth pat- tern with plenty draft very important producing smooth steel castings with this green sand facing. Ramming the Mold Care must exercised ramming. The idea which seems prevail, that steel molder can ram just hard cares without any bad results, wrong. All molds must rammed snugly around the outer edge— the part that forms the joint—but more softly and uni- formly over the pattern and between flanges. Soft ram- Fig. 3—Another Gating Plan for Globe Valve Mold. Additional inlet gates are shown ming between the flanges pipes valves reduces the danger cracks, allowing the casting contract. When mold rammed too hard the flanges pro- jections, such lugs, etc., are held stationary the hard mold, instead moving with the contraction the cast- ing. The result crack the junction the body the castings and the flange projection. Soft, uniform ramming very important reducing cracks and must practised all times. When ram- ming mold considerable depth necessary ram hard prevent the casting from swelling. such cases the ramming should done least in. from the surface the pattern. This will produce soft, uniform surface with hard background that will sufficient resist the excessive strain the mold and prevent swell the casting. Venting Important Green sand and molds for steel must vented, gl- though the character the proper green sand facing and heap sand makes possible produce many small steel castings without venting, because the sand coarse and open enough allow the gas escape. But cases where the molds must rammed hard, backed Iron Age, March 1930 hard ramming, the mold must well vented avoid scabs and cuts the surface the casting. These will produced the gas does not escape freely. The harder mold rammed the closer the grains sand are packed together. Consequently, there little chance for the gas work through the sand without the help vent passages. ramming deep molds advisable lay vent rods within few inches the pattern while ramming the mold, allowing one end the rods extend through the vent holes the flask, they can drawn out after the ramming completed. This plan provides free and pos- itive escape for the gas, and much more reliable than passages produced vent wire after the mold rammed. vent wire can, however, used many cases where there not any danger the gas not getting off quickly its use. Gating Should Bottom Whenever possible mold should gated the bot- tom, the metal will enter the mold the bottom instead the joint some other point higher up. making bottom pouring gates dry sand gate core should used. The advantage the bottom gate that allows the metal flow into the mold softly, which reduces the wear the surface the mold. The bottom gate many cases prevents blow-holes, because there less dan- ger air traps when the metal rises uniformly from the bottom. run light castings, lower the end the mold where the gate located enough compel the metal run slight incline. This plan keeps the metal traveling body, which causes remain liquid longer than when level, tipped the other way. Whenever possible all gates should formed the use set gates, rather than cut the gates after the patterns are drawn, because the set gate molded gate will withstand the wear the metal better than cut gate, regardless how well slicked. And easier thus regulate the size and shape the gate than when left the molder’s judgment. Gating must all times carefully studied. The metal must enter the mold softly possible, pre- vent excessive wear the surface the mold washing away delicate points the mold. The metal must enter the mold many points possible, avoid hot spots, which result shrinkage cracks. When gating mold the joint, possible have the metal from the inlet gate enter the mold directly under feeding head. This will prevent burn-down and brings the hottest metal into the feeding head when the mold filled. The five sketches are represent the plan gat- ing similar castings, avoid hot spots, cracks, etc. Fig. the drag mold for Y-pipe. The down-gate located The two gates leading from the down- gate are indicated BBBB, and the points where the metal enters the molds are CCCCCC. this case six inlet gates are used, with good results. Fig. the drag mold globe valve, the down-gate being located The two gates leading from the down- gate are marked BB. this case the gates flow under the core prints, connecting with two inlet gates each core print. This plan prevents cracks. Fig. another globe valve with the gating arrange- ment almost identical with Fig. except that two the inlet gates enter the flange, instead through the core print. This plan all right the flange not too heavy. such cases the gates should the core print. Fig. the drag mold for angle valve. The same plan carried out here, except that there inlet gate TI | 7 Fig. 4—Angle Valve Mold Gating Plan. Here, again, the designating letters are heavy section and, the metal were permitted enter this point, bad hot spot would created and crack would the result. Fig. the drag mold for Tee pipe. This mold gated the same Fig. The whole plan dis- tribute the metal and not allow enter the mold one place, when possible, and the production pipes and valves this possible. There are many larger castings and castings different design for which one gate necessary. But all times the question how the metal going cool should considered when making gate for steel casting mold. Feeding Heads Must Keep Metal Hot Feeding heads must large enough remain liquid longer than the casting they are feeding, when possible. They should the same diameter the riser pad they are the top end, keep the metal hot where enters the mold. Riser pads consist extension the pat- tern where the feeding heads are placed. They should attached all patterns used for steel molding, whenever feeding heads are required. They form the connection between the feeding head and the mold and this connec- tion can more correctly made the pattern shop, rather than have the molder cut the connection with tool. Feeding heads should connected with the mold the highest point, whenever possible, and always large enough remain liquid long enough feed properly. When several patterns are used flask, they must located manner which will allow sufficient room for side-feeding heads and gates, avoid trouble locating them when the cope placed on, ready for ramming. plan place the feeding head patterns the drag with the patterns, when locating the patterns. The gates the large molds will the bottom the green sand molds. This plan leaves the hottest metal the bottom the mold, when filled, and the hottest metal should the top. have the hot metal the top, pour the mold through the bottom gates until rises the feeding heads; then switch the pouring from the gate the risers. this time there will danger dirt being carried into the mold, already full metal. For the same reason, there will danger wear the mold from top pouring. But the time the Fig. 5—Gating for Cast Steel Tee Pipe, with Gates, etc., Designated before feeding heads are filled the hottest metal will the top for feeding purposes. Green Sand Cores for Pipes cast steel pipe will not crack readily green sand core used instead dried core. There are many cases where complete green sand core cannot used, account the trouble carry it, etc. many these the bottom half the core can made dry sand, and the upper half green sand, the lower half act- ing support for the upper green half. This upper half should made out the standard green sand facing mixture, should all green sand cores. When the bottom half core made and dried, and used support for the upper half, provision must made for holding the core down. This should done the use metal stool extending from the upper surface the lower dry half through the green half the sur- face the green half, where can held down with chaplet through the cope. Explains Peculiar Case Rusting Plates and Rivets The heavy rusting plates and rivets was discovered fairly new steamer. This was investigated and the re- sults are discussed the November, 1929, issue Korrosion und Metallschutz. According the author, Rudolph, damage rivets not unusual, caused frequently the continuity the coat rustproof paint becoming broken. this particular case the severe corrosion, extending parts depth mm. in.), was peculiar. The composition the plates was normal; they con- tained, however, considerable quantities oxidized slag inclusions, and these set local galvanic action which the plates acted anodes. Further, the corroded plates were found contain blowholes just under the surface. These hinder the passage heat through the plate; minute stress differences are set up, and the warmer part becomes less “noble” than the colder parts, and suffers attack. the corrosion penetrates the blowholes, matters become even worse; the sea water fills the holes, but oxygen cannot reach them, that difference aeration set up, causing corrosion the parts which the oxygen cannot reach. The unattacked plates contained less slag inclusions and blowholes. The Iron Age, March 1930—713 > Secondary Brittleness Rail Steel Bureau Standards Finds That Temperatures Existing Hot Bed Rail Steel Has Little Ductility properties rail steel elevated tempera- have been studied John Freeman, Jr., and Willard Quick the Bureau Standards. They note region reduced ductility 500 700 deg. C., ad- dition the blue brittle range (around 200 deg. C.). Typical results are given the accompanying illustration taken from their paper, “Tensile Properties Rail and Other Steels Elevated Temperatures,” delivered the February convention the American Institute Mining and Metallurgical Engineers. This so-called secondary brittleness present (though varying degree) all steels tested, including rails various history, hypereutectoid steel and iron. TS ——CL Ome TS As —Ciom * TS ANNEALED —-—f£ Po TENSILE STRENGTH LBS. PER ELONGATION AND REDUCTION AREA PER CENT 200 300 400 500 600 700 TEMPERATURE CENTIGRADE Physical Properties Specimens Taken From 100-Lb. Rail Made Under Standard American Practice, When Tested Tension Somewhat Elevated Temperatures excessive amount secondary brittleness apparently property the heat whole, and suppressed part annealing either below above the transformation. does not seem related chemical analysis, nitrogen content, silica, alumina manganese. Test pieces break- ing 600 deg. and thereabouts show the characteristic brittle fractures, and the cracks appear follow the grain boundaries. the supposition that this inferior ductility hot metal might the cause the well known “shatter cracks” rail heads, the authors constructed temperature- time curves rails, the surface, midpoint and center, during cooling various rates speed. Even when cooling still air the surface about 150 deg. cooler Iron Age, March 1930 than the center when the latter passing through the secondary brittle range (600 deg. C.). that time the surface set into strong and more rigid condition, un- yielding the contraction occurring the hotter and more brittle center. the authors’ opinion this could explain the formation shatter cracks rails, which turn are supposed many the nuclei transverse fissures. They therefore recommend slow cooling for rails and other massive steel parts such rate that the center and surface are within relatively few degrees each other all times. the discussion, Robert Job, vice-president Milton Hersey Co., Montreal, Canada, reviewed the present state opinion transverse fissured rails, emphasizing the fact that their occurrence very sporadic, and then only after the rail has been under traffic. other words, heat rail steel may have predisposition toward transverse fissures, but the fissures themselves not exist when leaving the mill. Dr. Gillett, director Battelle Memorial Institute, Columbus, Ohio, remarked that, for that very reason some test, such for secondary brittleness, which could made each rail heat the mill, ought valuable means preventing dan- gerous metal from being placed the track. Prof. Albert Sauveur, Harvard University, Cambridge, Mass., reminded the audience that his recent Campbell memorial lecture before the American Society for Steel Treating had shown evidence that the many steels tested had diminished ductility the vicinity 600 deg. suggested that the reason the fractures that tempera- ture range favor the grain boundaries because the heat above the equi-axing temperature, where the amorphous phase becomes weaker than the crystalline phase. Forest, Page Steel Wire Co., Bridgeport, Conn., said that even though the ductility the hot inside rail heat possessed diminished amount ductility, would not break unless was stressed beyond its ultimate strength, nor could one imagine that the stretching inside rail head would approach the dangerous elongation for the most brittle steel (five per cent). actual cracking occurred would very small area where the duc- tility considerably lower than the statistical average. This immediately suggested others present the infer- ence that internal weakness due weak centers (such inclusions, thought some the prime cause in- ternal defects). British Researches Cast Iron CUPOLA has been built the Carron foundry from designs made Fletcher, consultant for the British Cast Iron Research Association, which great advance has been obtained both economy and cleanli- ness operation. present the furnace producing 100 tons daily metal 1400 1425 deg. C., (2550 2600 deg. Fahr.) suitable for very thin castings, coke consumption about per cent. 7 7 Welding Practices Big Tank Shop Problems Encountered Baldwin Locomotive Works When Instituting Welding Manufacturing Method and How They Were Solved THUM been done the Baldwin Locomotive Works. the boiler shops has been found very useful avoiding concentration metal seams water legs where dan- ger overheating ever present, and such other appli- cations stayed surfaces are permissible under official regulations and codes approved the purchaser’s inspectors. other departments the cutting and welding equipment had been used principally for repair work, and only here and there unimportant engine fittings. How- ever, rapid development welding has taken place recently the tender shop, matter which will form the basis the present article. some years considerable amount welding has The truck and tender shop one the most recently constructed units Eddystone. major fraction the floor space devoted the fabrication the tender tanks, and this was installed the most modern equip- ment adequate for bending, punching, erecting and riveting tank plates the maximum shipping widths and lengths. Its size may appreciated when said that many 1200 men per shift have been engaged this minor subdivision locomotive manufac- ture. the result thorough engineering and production IG. 1—Dished End Vanderbilt Tank with out for riveted joint top; for welded joint bottom (above) IG. 2—Sections Water Tank and Tender Frame, Showing Diaphragms. Detail right, top, shows welded construction; bot- tom, riveted construction study the possibilities welding applied tank work, the Baldwin Locomotive Works adopted the position little over year ago that unless otherwise specified tender tanks would completely fabricated welding. This despite the fact that such change would render moribund considerable quantity recently purchased fabricating machinery, air compressors and riveting equip- ment, and introduce serious personnel problem among employees, many whom had given faithful service for long years. How far this movement has gone evident from the fact that four out every five tenders now being built have welded tanks. And nearly all them are the huge affairs holding 23,000 gal. water and tons coal, required for the present practice running engines through traffic over two three the old divisions before uncoupling. Welding Favored Purchaser and Ma