The Iron Age 1929-06-06: Vol 123 Iss 23

THE IRON New York, June 1929 ESTABLISHED 1855 Using Ram-Up-Cores for Castings Advantages Stressed Are Lower Molding Cost, Better Castings and Less Danger Spoiled Work PAUL RAMP* ANY valuable articles written foundry practice have done much advance efficiency foundry work. Perhaps too much cannot written, not only for the information that broadcast all who read but for the tendency has make readers think, and then develop greater things than those they read about. However, must not neglect the simple things, be- cause the rising generation must know about them, well about the most advanced practice and recent discover- ies. Without the simple things they will not have the proper foundation upon which build their foundry edu- cation. With this mind the writer proposes discuss one the simple things that has considerable bearing the quality and cost castings, namely, “Ram- up-cores.” There are many cases where ram-up-cores are used advantage. There are many where ram-up-cores could used advantage, but are not used because some not realize their value, and others not know how use them. For the benefit these persons few cases where ram- up-core advantage the production good reasonable cost, and better than core put core print. The first example special pipe for high- pressure steam line, which Fig. gives two views. The difficulty en- countered making this pipe the molding the side branch marked pattern Side Core, foundry shop, Newport News Shipbuilding Dry Newport News, Va. Fig. (Above)—Special Cross Pipe for High- Pressure Steam Line Fig. (Below)—Pattern Board, with Ram-Up- Core Place Form Flange parted the line DD. This makes necessary use three-part flask, use covering core over the flange, use loose flange sections, picked after the main pattern has been drawn out the sand. All three these methods are expensive and unsatisfactory, because: The three-part flask method calls for exceptional mold- ing ability and additional time, and there more danger the scabbing and dropping out. The covering core method requires special care placing and ram- ming, and there always the danger dropout the green-sand side the flange mold that covered with the covering core. This dropout caused the vibra- tion and drawing the main pattern, because, before the pattern drawn out the sand, the flange sec- tion already been taken out the sand; and unless this part the mold very carefully nailed supported, there danger part dropping. The method making the flange pattern and several pieces, and picking them after the main pattern drawn out the sand, slow and expensive process. There always danger the molder loose pieces crooked too hard, causing the sur- face the mold cut, too soft, causing the casting swell. the use ram- up-core the possibility cuts, scabs, dropouts and swells eliminated, be- cause the flange itself really dry-sand mold. Fig. shows the drag half this special pipe ing board, with the ram- loose Core Print VOL 123, No. \ — 1549 up-core, which form the flange the branch pipe position. practice, the first operation this case will place the flask the board and ram the mold the point where the ram-up-core meets the green sand; then the ram-up-core will placed position shown Fig. This ram-up-core usually made two pieces and joined together. One piece consists ring core, the opening the conform the outside diameter Fig. 3—(Above) Cross-Section Mold for the Special High-Pres- sure Pipe Crossing, Showing How the Ram-Up-Core Fits General Scheme Figs. (Below) and (Right) Are Cast Steel Lifting Pad and the Drag Mold Used Making It. The latter shows the ram-up-core place the pattern; the other piece conform the outside diameter the flange required, and the outside diameter the core print. After the flask rammed full sand, the cope part flask lifted off. The drag pattern then drawn and further work except removing loose sand necessary, produce the flange the side branch Fig. cross-section this special high-pressure pipe mold, showing all cores place, including the ram up-core which forms the flange the side branch. will noted that the ram-up-core does not cover the end the side-branch main core, much tighter joint can made forming the end the print with green sand. Making Plate with Eye-Link Fig. shows cast steel lifting pad, which consists cast steel plate with lifting eye-link cast it. 1550—June 1929, The Iron Age cross-section the drag part mold for these lifting pads, rammed full sand, shown Fig. with the pattern and the ram-up-core place. The cus- tomary method used mold pattern this design split the pattern and mold the plate section edge; this makes possible form the eye-link section green sand. The objection this plan that deeper cope must used, and gaggers and nails must used hold the sand the cope, prevent from dropping out when the mold being closed. the upper edge the plate that molded the cope half the flask rammed too hard, blowhole will result, and there always danger blowhole from hard ramming molds where the patterns extend very far into The reason for this that the molder afraid inclined ram his cope too hard. the cope. Another disadvantage split pattern the shift either the flask the pattern, and half pattern the cope often rammed out line, causing mis-match. Although there may not shift cast- ings made this way, there will seam fin the casting, produced the parting line. And there shift with the split pattern, there would always high Core point the center the plate, where the cope and the drag mold join, because necessary allow draft the two halves the pattern, and this produces high place the center the plate. Another objection this plan making these link pads that requires more time mold split-pattern job than does flat- back, and more experienced molder. With the ram-up-core shown Fig. the job be- comes very simple flat-back which does not require experienced molder make. The eye-link made per- fectly with shift, and the surface the plate section straight, with high points parting lines chipped off. With the ram-up-core not only possible make the mold more cheaply, but the cost cleaning and chipping steel casting this character reduced one-half. The additional cost making the ram-up-core only small percentage the time and labor saved its use, and much better casting produced. Making Pulleys This Method Often are obliged make special pulleys small diameter with wide face. This design produces mold delicate ring pocket sand that very hard secure green sand. And often, after has been properly se- cured, the question venting this frail column sand this character; the inside part this pulley mold made using ram-up-core. This ram-up-core dropped into the pattern before any sand put into the flask; after the drag portion the mold has been rammed, the flask rolled over, the joint made, and the cope half the pattern placed the proper position, another ram-up-core dropped into the cope pattern. The cope ram-up-core provided with — sprue which leads the hub section the pulley mold. This plan the necessity rodding the green sand pocket, and prevents cut scab the points mdicated the letters AAAA. also makes possible gate the mold the hub section, which assures cleaner face the pulley. making ram-up- cores pulley this kind, advisable have the outside diameter the ram-up-core come flush with the outside diameter the pattern, the case Fig. When the ram-up-core allowed extend over the out side diameter the pattern, there always danger soft spots being produced the green sand section the mold, under the ram-up-core where joins the pat- tern, which would result swell, producing deformed casting. Many similar castings with deep pockets can more economically produced with ram-up-core than placing core core print, attempting make the mold green sand. Ram-Up-Cores Need Adequate Support When ram-up-cores are made for deep, narrow pock- ets they must extend into the green sand far enough enable that portion the mold carry their weight. This prevent the ram-up-core from dropping out the mold when the cope placed the drag. course, possible hold ram-up-core place with wire, nails chaplets. But one the important things about ram-up-cores that, they are properly made, they elim- inate the necessity for nails, wire chaplets. \ Fig. 6—Cross-Section Small Web ley Mold, Showing Ram-Up-Cores Cope and Drag and the Hub Core Fit- ting Between Them. this case the only contact between molding sand and casting working surface pulley Quality Castings and Large Use Scrap scrap mixtures problem which con- cerns every iron and steel foundry today, declared Smith and Riggan, metallurgist and associate metallurgist respectively, Stockham Pipe Fittings Co., Birmingham, Ala., the recent annual convention the American Foundrymen’s Association Chicago. Every furnace has consume portion scrap, ranging from moderate amount remelted gates, etc., 100 per -cent scrap mixture, they asserted, paper entitled “The Use Scrap Gray Iron, Malleable and Electric Steel Mixtures.” Associated with this problem question great importance—how maintain steady improvement the quality the product. Charges Containing 100 Per Cent Scrap The authors, their 20-page paper, take many phases the giving analyses some the common grades for the various kinds castings, well discussion specifications. The effect the product varying percentages scrap the mixtures illustrated photomicrographs 100 and 500 diam- eters, showing ranges 25, 50, and 100 per cent scrap. valuable section devoted effects borings, tin, zine and burned material. Rapid progress becoming nationally organized being made the scrap industry, declare the authors. Cooperation between purchasing agents, scrap metal deal- ers and the Department Commerce has resulted specifications suited all types furnaces and all grades scrap. keep step with improved quality, both the process and the selection materials must under closer control. Future Scrap Yards Will Have Balers and Furnaces The scrap yard the future will probably equipped with briquette machines, balers, furnaces, magnetic sepa- rators, and even chemical laboratory. individual problem for each foundry decide what kind scrap can use and how much it. most cases relatively small amounts scrap may used with improvement quality and some saving cost. There place where each kind scrap metal can used advantage, whether the air furnace, cupola, electric blast fur Some exception was taken the statement the authors that, after adding both tin and zinc the ladle where 100 per cent scrap gray iron was used, little effect was found either the analysis the physical prop- erty the product. ordinary practice, however, the zine probably volatilizes and seems probable that tinned galvanized material moderate amounts will have effect the quality cast iron. One speaker, questioning the results the effect tin, stated that per cent tin mixture had low- ered the transverse strength the castings from 3750 2350 and Lowry, consulting metallurgist, Detroit, declared that the tin absorbed and becomes hardener. Heat Transfer From Gases Solids The efficiency blast furnace gas producer de- pends upon the proper transfer heat from moving gases colder solid particles. general, heat trans- mission function the physical properties the mass solid particles. The North Central experiment station the United States Bureau Mines, cooperation with the Uni- versity Minnesota, Minneapolis, has started in- vestigation for obtaining quantitative information which will guide operators making such innovations prac- tice will best satisfy thermal requirements. The transmission heat from water flowing through bed steel balls about in. diameter being studied first, with view finding some fundamental relafions that can applied systems which heated gases are passed through mass low-conductivity particles. The Age, June Pouring Basin ety) \) | \\ \ | | UILDINGS and mechanical equipment for the tin mill recently built the Youngstown Sheet Tube Co. East Chicago, Ind., were designed permit the product flow continuously and progressively through the operations the quickest and most economi- cal manner. The departments are that the sheet bar, when unloaded from the cars, passes through one building and one process after another progressively, until the finished product loaded into cars the other side the plant. Hot mills, housed separate building, consist mills with pair and sheet furnaces. front the rolls, lean-to off the main hot mill building, are the squaring shears and opening floor, where the sheets are sheared and opened, weighed and assembled according order. Box annealing has been made continuous and automatic through the installation kiln-type furnace, gas fired and equipped with automatic heat regulators. The pots containing the sheets are placed trucks and then charged the furnace. Cold rolling equipment lean-to between the black and white annealing buildings. There are trains rolls, three sets rolls each train, with conveyors between the sets, carry the sheets automatically through. After white annealing, the sheets the white pick- ling department, where they are again pickled, obtain clean steel before coating. Immediately after pickling, they are placed steel boshes containing water, pre- vent oxidation during transportation between the two processes. There are tinning stacks, each with automatic continuous tinning machine. This equipment consists three main parts: the tin pot which holds the molten tin, the tinning machine and combustion chamber heated with special system combustion. *Assistant the president the Great Lakes Corpo- ration, Detroit. General description of the Youngstown com- pany’s sheet and tin mills was given in our issue of Oct. 14, 1926, page 1062 Row Tinning Units, Each Containing Gas Furnace, Tin Pot, Automatic Tinning Machine and Scrubber 1552—June 1929, The Iron Age Tin Pot Heating Radiation from Incandescent Bed Refractory The pot, partly filled with molten tin, divided reaching part way down from the top. The back end filled with palm oil, which rests directly the tin, and partly insulated from with coating dross. compartment the front side the pot the sheets are placed end, slanting slightly toward and against the front side for feeding the machines. The first set revolving rolls located this compartment and magnet within draws the first sheet over until contacts and drawn through. Feeding from one set rolls another, the sheets pass over the side this compartment, down into the tin bath, under the apron, through the tin machine, through the hot palm oil another set rolls the catcher. The catcher flops the sheets over slide, from which they proceed roller conveyor for transpor- tation cleaning machine. The coating tin acquired the tin bath and the hot palm oil serves smooth and even the coating the sheets pass through the rolls. the temperature the tin bath must maintained within very close limits, system firing was installed which close control possible. The bottom the pot the floor level and the combustion chamber below. deep brick structure serves foundation and the front this, just under the front edge the pot, the combustion chamber. row gas burners fire into this chamber angle that the flames impinge bed broken re- fractory. This bed heated incandescence and the heat transferred directly the bottom and front side the pot through radiation. This system was designed and installed the Surface Combustion Co., Toledo, Ohio. Five gas burners are spaced equal intervals along the length the combustion chamber, one manifold serving three and another two. Each manifold pro- vided with gas-air inspirator the venturi type. flue one end the combustion chamber removes prod- ucts combustion, and damper installed which the pressure the chamber maintained constant. — Hot Rolling Mills, with Sheet and Pair Furnaces Left. Cooling air comes from the cowls shown the Annealing Department, Showing Ample Area for Handling the Product The Iron Age, June Charging End Sheet and Pair Furnaces, Showing Arrangements for Handling Sheet Bar and Fuel Silica Refractory Material Consideration Its Use Steel Industry— High Melting Point Essential— Relations Other Oxides ROBERT EFRACTORIES and slags together bear the same kind relation the manufacture steel that the soil bears the growth corn and wheat. both cases the principal constituents come from without, yet the soil contributes its own small proportion useful substances and various other ways important factor the final yield. Silica Raw Material One type requirement for good refractory ma- fundamental every one must abundant and ac- Silica meets this re- terial will recognized connected with the industry; cessible enough make cheap quirement such high degree place class itself when compared with other refractories. regrettable that popular material should have its faults, but the recognition faults must precede the introduction improvements, and propose therefore silica consider the following weaknesses exhibited when used refractory: (1) Its low elting rregular the il expans (3) I tivity in slagging with other oxides -points some common refractory oxides are Magnesia MeQ 2800 I CaO 2570 Alumina ALO 2050 Chromium oxide CroO 1990 Silica SiO 171 The melting-point silica given only the highest three different points, for there are three distinct This abstract paper read May 24, before the Americar Steel Institute, New York, and the discussion ORN southern Ohio 1881, Ph.D. physical chemistry the Massachusetts Institute Tech- After two years with Arthur Little, Inc., nology. physicist the geophysical laboratory the Washington until 1928. nitrate division the Bureau Ordnance. Washington. 1554—June 1929, The Iron Age Robert Sosman was graduated from Ohio State University and 1907 was given the degree Carnegie Institution the war was consulting chemist the the Washington Academy Sciences and the Philosophical Society now physical chemist, research laboratory, United States Steel Corporation, Kearny, SOSMAN crystalline forms modifications silica, each which has its own melting-point. These forms are: Quartz melts deg. ........ 1400 Tridymite melts deg. ..... 1670 Cristobalite melts deg. .... 1713 The melting-point quartz given this list 1400, but you will have exercise great deal pa- tience induce melt that temperature. Silica belongs limited class substances which are charac- terized very slow rate melting. The diagram shows that quartz held 870 deg. would change into the form known tridymite. slow heating this turn converts itself into cristobalite 1470; the latter melts 1713. But these changes are sluggish. Quartz can heated several hundred degrees above its melting- point and, the heating has been done quickly, can cooled again without showing any essential change. Reverse changes are also sluggish; tridymite, cristobalite and vitreous silica are all obtainable with ease or- dinary temperatures, and will stand unchanged for years, although thermodynamically unstable. The melting-point cristobalite unfortunately just little below the most effective temperature the open-hearth furnace. 1713 deg. the absolute deadline for the silica roof. Nothing can done about this limitation, because general rule the addition anything pure substance lowers the temperature which will liquefy. Thermal Inversions and Expansions The second important limitation pure silica refractory found the sudden expansions which the forms undergo relatively low temperatures. The diagram shows that each variety SiO. has changes (similar the allotropic modifications steel) fairly low temperatures. These are associated with consider- Boston, was ‘4 able change volume, that tridymite least, cris- tobalite greatest. Three ways suggest themselves which the diffi- culty due these sudden expansions can materially Decrease the amount sudden expansion. Decrease the suddenness the expansion. Improve the mechanical qualities the refractory. The first possibility has already been suggested comparing tridymite with cristobalite. Tridymite has very small expansion both its two inversion points. brick consisting entirely tridymite will therefore have very little more likelihood spalling than com- mon building brick the same size. Modern practice brick making consists more less complete con- version the original quartz into cristobalite, which the first result heating high temperatures; there also effort toward increasing conversion the cristobalite into tridymite. There seems other practicable way reduc- ing the amount expansion. may remarked 2000°C ' Superheated, Quartz ~ ‘> & 870 573 c 9 i= 97207 Temperature Chart Changes Stable Forms Silica, and High-Low Inversions Associated with Expansion Contraction Volume passing that quite hopeless attempt resist this expansion mechanically. Everyone knows the futility trying resist the expanding power water when freezes. are dealing with change which not something superficial; begins with the atoms them- selves. true that the temperature inversion cristobalite can changed pressures, but the amount pressure necessary raise such inversion point from 200 deg. temperature where would harmless would measured thousands millions tons per square inch, certainly pressures far beyond the strength any ordinary engineering structures, such can built around furnace. second possibility for improvement decrease the suddenness the cristobalite expansion. Cristobalite which has been made 1300 deg. has lower inver- sion point than cristobalite which has been made 1600 deg. Likewise, cristobalite made from vitreous silica shows different inversion-temperature from cristobalite made from crystalline quartz. Suppose can find some practical way making cristobalite large scale succession batches which will show different inversion points; these might then mixed and bonded make brick which the inversion point would not suddenly one tem- perature, but would spread over range deg. 100 deg. quite that the suddenness application the stress will very much ameliorated. not all sure but that this very thing un- intentionally accomplished present practice, the mixing material various degrees fineness. The very fine grains quartz probably transform cristo- balite while the temperature still rising, while the coarse particles are only transformed during the soaking period. The third possibility very different character from the two just mentioned. lies the improvement what may rather inaccurately ealled the “elastic qualities” the brick. ordinarily forgotten, when speak the frac- ture brittle substance irregular heating, that must take into consideration physical qualities not or- dinarily shown crystalline substances, namely, fluidity and plasticity. The interstitial silicate glass silica brick may show measurable fluidity yielding slowly very small stresses, may show plasticity be- ginning flow only some definite stress below which unaffected. either case, the resulting readjust- ment will relieve the stress that caused unequal heating. Relations Silica Other Oxides The bonding silica particles into brick and the re- actions between finished brick and slag hot dust in- volve consideration the reactions between silica and the oxides lime, alumina and iron. Data most fundamental importance have been sup- plied only within the last year two the researches Greig the Geophysical Laboratory Wash- ington. His work amplifies and extends series re- searches silicate systems that had been carried for- ward that laboratory during the preceding two decades, From detailed study these equilibrium diagrams appears that the calcium silicate which cements the grains cristobalite and tridymite the must present liquid the working temperature the furnace, and therefore little effect bond. seems rather that the cristobalite and tridymite grains themselves must have grown together make con- tinuous, though porous, structure, sponge. something like The so-called lime bond low-temperature bond only. may act between the grains the green brick, and may subsequently become vitrified cement after the brick has been fired the kiln and cooled, but fair question whether serves any useful purpose all the higher temperatures. These facts suggest once the possibility making brick pure silica with additions whatever. Experiments this direction have been made, but without much The most recently recorded ex- periment the making standard-size silica brick with- out the addition any bond gave brick that were slightly more porous but only about one-half strong ordin- ary temperature lime-bonded brick. The desired result mechanically rigid aggregate crystals cristobalite tridymite, either intergrown like the fibers textile felt, molecular con- tact face face that the crystals achere with the strength characteristic chemical combination. Perhaps this result can secured with the aid added sub- stances which will serve only the temporary functions (1) bond for the green brick, and (2) catalyst for the intergrowing autogenous welding the crys- tals; and which will then disappear entirely. Only con- The Iron. Age, June Silica nn tinued research and experimentation can sound out these possibilities. Care Adds Life Silica Brick one-third the brick, which number roughly for each ton steel made the open-hearth furnace, are silica, said Dr. Unger the research de- partment, United States Steel Corporation, discussing Mr. Sosman’s paper. For this type brick there real substitute. These brick have certain amount iron oxide them after they have been use, particu- larly those employed open-hearth roofs. This iron oxide, together with small amount lime, come into the brick through having been taken from furnace fumes. This leads the thought that perhaps might well add certain amount iron oxide the mix- ture which the brick are made. The iron oxide seems least good binder the lime customarily used. Over the acid open-hearth furnace the roof lasts ap- proximately four times long that over the basic fur- nace, although both are made the same happens that the fuel cost making steel about twice much for each ton steel the brick cost. For this reason more economical run the bricks early destruction than burn extra fuel, and the furnaces are often operated this basis. Three characteristics silica brick were outlined Walter Kelly, refractories engineer the Bethlehem Steel Co. These are: their rigidity under furnace tem- perature and pressure conditions, the negligible spalling which they show under these conditions and their fluxing action. Manganese and chrome brick fail under tempera- ture conditions 2550 2600 deg. Fahr. Silica brick, however, maintain their strength pretty well almost their melting point 1730 deg. 3115 deg. Fahr. silica brick are kept always above dull red heat, they can subjected violent temperature changes without much danger spalling. only when they are allowed cool below dull red heat, and are worked back and forth through that temperature range, that trouble comes in. particular, they are heated too rapidly from cold furnace they will spall. New Press Increases Automobile Frame Side-Rail Output automobile frame side-rails are formed simulta- neously the 2000-ton press illustrated, production being the rate 720 side-rails 360 frames hour. This machine, thought the largest its kind, has enabled the Detroit plant the Midland Steel Prod- ucts Co. increase its output and the same time main- tain high standards quality. was designed the Midland company cooperation with the builders, the Hooven, Owens, Rentschler Co., Hamilton, Ohio. Maxi- — | 7 > Press 2000 Tons Capacity Installed the Detroit Plant the Midland Steel Products Co. 1556—June 1929, The Iron Age mum strength and rigidity, order eliminate, far possible, deflection the bed, slides, crankshaft and crown, were primary aims designing the machine. The bed one-piece casting and weighs tons. The slide weighs tons and the arch tons, the total weight the machine being 400 tons. The height overall ft. duplicate this press being built for the Mid- land company’s Cleveland plant, the arrangement and some the methods which were described THE IRON AGE July 1928, page 19. Large Carbon Deposits Inside Blast Furnace Explained Deposits carbon, several inches away from the hot face the upper part blast furnace, have been found some corroded brick where the temperature does not exceed 500 600 deg. This phenomenon reported the Glasgow, Scotland, meeting the Ceramic Society recently. This product was assumed the result dissociation carbon monoxide and the research was made the authors discover the probable causes this deposit. the paper the authors describe the experiments and the apparatus detail and discuss the results, brief summary which follows: The following catalysts (agents which not undergo any permanent change themselves) promote dissociation carbon monoxide the temperatures ranges temperatures given: Pure kaolin, 450 and 470 495; pure silica, 520 570; pure alumina, 260 and 350; firebrick, 410 and 430 and 500; kaolin treated with aqua regia, 480, and 520 545; silica brick, 530 540; re-burned firebrick, 380 and 470; Scottish firebrick, 340 450 and 470 500; calcined clay, 300 400; calcined dolomite, 370 770; and pure ferric oxide, 300 700 deg. Mellor’s theory the decomposition clay was sup- ported. was found that the better burned brick was, the less was the dissociation; the latter could also re- duced decreasing the iron oxide content the clay. The burning brick appeared bring out the lower (alumina) and the higher (silica) temperature effects. Less Noise—Better Work Sound-Absorbing Walls and Ceilings Improve Working Conditions Factory Office—Mechanical Ven- tilation Contributes Comfort populated factory of- fice, with its chorus typewriters, adding ma- chines and human voices, often runs close second many the factory’s manufac- turing departments. Sound energy and, once produced con- fined room, will con- tinue exist until ab- sorbed the boundary surfaces, leaks through the doors and windows. Although the desirability noise prevention, both within and outside buildings, has been much dis- cussed, actual measures subdue noise are, the indus- trial field least, still something novelty. recent example progressiveness dealing with this problem found the new administration build- ing and employee’s auditorium the Co., Water- bury, Conn., the walls and ceilings the several rooms which have been soundproofed the application %-in acoustic felt. The felt the walls extends the top the wainscoting and covered special acous- tically painted muslin, the finished appearance being comparable high-class plaster work. The felt the ceiling covered perforated and painted material that resembles oilcloth appearance. addition the concrete floors are covered with 5/16-in. thick rubber. sense this acoustic treatment may thought “carpeting” the walls and ceiling, except that carpeted floors are credited with sound absorption value only per cent, whereas the wall and ceiling treatment used the Bristol company’s building accorded the noise produced the vari- ous rooms. The familiar quiet- ing effect carpet other- wise hollow room may thus serve com- parative basis for comprehend- ing the effectiveness this wall and ceiling treatment. The building treated three-story, U-shape, steel, concrete and brick structure with frontage ft. and maximum depth 145 ft. houses the executive offices, publicity, accounting and sales torium for foremen’s meetings and other employee activities. The auditorium occupies one leg the building; the recep- Treatment the Ceiling Shown Above, with the Perforated Kribble Cloth Covering the Felt Layer, Which Cemented tion hall, executive offices, directors’ room, publicity, ac- counting and sales divisions occupy the front and other leg. The publicity division, with the printing and supply the accounting division ft. room the first floor, while the sales division occupies several rooms the top floor. The latter comprise offices, con- ference rooms and one large demonstration room, upon the walls which are displayed the various types and styles recording instruments manufactured the company. The auditorium ft. long ft. wide and has ft. ceiling, the ceilings the other rooms, being 10% ft. high. each floor are women’s rest rooms, fully-tiled wash rooms and outside record vaults, while commodious locker space provided for employees the basement. The sound absorbing material used known Akousticos and made the Johns-Manville Corpora- tion, New York. asbestos fiber and hair com- bination that possesses porosity and flexibility. The perforated covering for the ceiling felt known Kribble cloth, the name being derived from cribble, the dictionary definition which coarse sieve with round holes. This material painted and perforated before being cemented the felt, the object the perforations being increase the sound absorbing quali- ties the bare felt over the entire pitch. addition absorbing high percentage sound the average pitch office noises, the felt fire resistant and reflector light. The walls, painted cream color, are credited with light reflecting factor per cent, while the ceilings, done white, have light reflecting factor per cent, these percentages being comparable the standard factor per cent for carbonate magnesia. The appearance the walls and ceilings pleasing, and the covering materials may cleaned redecorated economically with- out materially affecting the sound absorbing qualities. The ceilings may washed like lacquered painted with flat wall paint means special process that obvi- ates filling the perforations the Kribble Along with the sound proof- ing, there are several other features that assure comforta- ble working conditions for the 100 more employees this building. One these the “outside” location all record vaults, and the other the at- tention ventilation. Each division, accounting, sales and publicity, has large steel-furniture ord vault. Each vault has J The Iron Age, June - ~ — | | Decorative Frieze Above the Upper Windows, Three Which Spans three large wire-mesh glass windows that provide both daylight and fresh air, permitting those working the vaults with much convenience any other room the building. mechanical blast system that supplies clean and tempered air the rate 20,680 cu. ft. per min. supplemented mechanical exhaust system that re- moves impure air the rate 14,000 Fresh air may supplied mechanically all rooms, and impure air exhausted mechanically from all but the private offices. The system designed exhaust per cent the supply, creating slight plenum pressure. Me- chanical exhaust was not provided for the private offices because was desired maintain higher pressure those rooms eliminate drafts. Air Washed and Humidified Fresh air taken from the outside, tempered, drawn through air washer and humidifier and then re- heated and discharged into the various rooms, including the auditorium. The fresh air equipment includes Sturtevant No. 100, design double-width Silentvane fan coupled motor. The fan, the same general type those used the Holland Vehicular Tunnel, has capacity 20,700 cu. ft. per min. against 1.4 in. re- sistance. There are two tempering coils, each consisting four rows pipe, with total heating surface 668 sq. and two reheating coils, one four row and one two rows, made pipe. The air washer and humidifier 7-ft. Sturtevant type with humidity control equipment and motor-driven centrifugal pump for recirculating the water. The humidifier furnished with two banks spray heads having tors the entering side and with vertical eliminators and flood nozzles, marine type electric light, pressure gage and large glass-paneled access doors. Casings con- nect the fresh air intake the tempering coils, the tempering coils the humidifier, humidifier the re- heaters, and the reheaters both inlets the fresh air fan. are furnished the fresh air intake and louvre dampers are provided for shutting off the outside air when the fan not running. The exhaust equipment consists Sturtevant No. 100, design Silentvane fan, single-width, single-inlet, direct-connected 5-hp. electric motor with starting compensator. The capacity 14,000 cu. ft. per min. air against static pressure. This equipment not operated continuously when adequate ventilation had means the unusually large Austral type win- dows each room, although even such times the mechanical blast and exhaust system put operation for min., four five times each day. Benefits Are Real, Though Intangible Return money invested these improvements derived from increased general efficiency made possible the elimination distractions caused excessive noise, wasted energy due poor lighting and the discomfort and slowing down caused inadequate ven- tilation. Then there are considerations improved morale. The building, extra expense, pleasing ar- chitecturally, and the unusually good working conditions, doubt appreciated consciously unconsciously the employees, tend definitely minimize labor turnover. Wider Use Aluminum Alloys Busses and Trucks aluminum alloys the manufacture truck and bus bodies ard chassis increasing. the mod- ern bus, where light design, well strength and dura- bility, are prime requirements, the trend toward aluminum alloys the manufacture component parts espe- cially apparent. One prominent truck manufacturer using all-aluminum radiator shell, the upper and lower portions acting reservoirs. process casting, threads are included for securing the radiator cap. This same manufacturer using aluminum alloy side boards, extending from the cowl the running boards and sup- porting the gasoline tank. Many other parts also are aluminum alloy, the steering wheel spider, the instrument panel, crank- case, transmission case, brake shoes, floor boards, step plates for the running board, accelerator pedals and head lamps. number smaller parts, such throttle levers and minor connecting links the spark and throttle con- trol, also are aluminum. the engine proper, the 1558—June 1929, The Iron Age entire lower half the crank case, main bearing caps, connecting rods, pistons and many accessory parts the carbureter, ignition, water pump, starter and gen- erator are of. aluminum alloy. These various parts, all acting some individual ca- pacity, present problem, not only the particular alloy, but the process casting and heat treatment. Three processes are used making aluminum alloy products: permanent mold, die casting and sand casting. The per- manent mold casting produced pouring metal, under the sole pressure gravity, into cast iron mold around collapsible steel cores, contradistinction die casting, where the metal forced into the mold under pressure. Selection the best process for casting particular part, the alloy used and the heat treatment determined best careful study the part and the function for which designed. Some parts cannot made the permanent mold die casting process, par- ticularly those intricate design. ~ | ) y Regenerative Furnace Principles Their Theory and Application Discussed—Influence Air Infiltration—Distribution Waste Gases MCLOUGHLIN the course which combustible gas evolved, those factors which determine the most efficient design heat recovery apparatus are means constant. show the variation these factors typical open-hearth heat made with by-product coke-oven gas was chosen, and observations made 5-minute intervals. The fuel supply varied from 95,500 cu. ft. per hr. 53,800 cu. ft. per hr. minimum. Variation the volume waste gases tempera- any metallurgical operation, and especially those McLoughlin has been the employ the Carnegie Steel Co. For years was identified with various operating departments, such the blast furnace, the open-hearth and the rolling mill divisions. During the past five years has been engaged fuel and special engineering work for the the Stevens Institute Technology and director the Engineers’ Society Western Pennsylvania ture 2800 deg. Fahr., the temperature which the gases should enter the regenerative chamber well built open-hearth furnace, varied from 3,600,000 800,000 cu. ft. per hr., although one peak ran 6,400,- 000 cu. ft. per hr. This gives some idea the changes velocity the entrance checker openings regen- erator and serves explain some the changes air temperature encountered successive cycles regenera- tion. Density waste gases varied from 0.0114 0.0119 (at 1400 deg. Fahr.) and the mean specific heat the waste gases while the checkerwork (2800 1400 deg. Fahr.) varied from 0.230 0.246 B.t.u. These figures serve illustrate the reasons for the ever-changing rate heat transfer well the low rates heat transfer the lowest portion the chambers. The effect the personal equation the results ob- tained with given regenerator often very decided. Two successive heats open-hearth furnace having identical charges may tapped hours from the start. These variations fuel supply, and the frequency This abstract paper read May 24, before the American Iron and Steel Institute, New York, and the discussion which evoked. reversals, often represent the difference between the judgment good and average first helper. Effect Increased Checker Depth Since the rate heat transfer directly propor- tional the velocity and also the difference tempera- ture between the waste gases and the absorbing surface, and since increased checker depth reduces both the veloc- ity and temperature difference, evident that consid- erable increase depth must made effect slight dif- ferences temperature the preheated However, most open-hearths depend upon the draft produced the hot checker chamber and port uptakes draw air through the regenerators the furnace. deepening the checker chambers this draft increased and more air can supplied the furnace. This in- creased volume air increases the rate heat transfer and, therefore, the final temperature and also enables the operator burn fuel increased rate, thus aceelerat- ing the melting down stage, and thereby increasing the rate production per unit time and decreasing the fuel consumption per unit product. Heat Balance Furnace and Regenerator order exemplify the extent which regeneration can carried and show its effect, three heat balances have been made. The first actual balance taken tar-burning open-hearth furnace, which has relatively checker chamber and high rate fuel consumption per ton steel. The second shows that the furnace pro- ducing the same rate, but double the waste heat being returned preheated air, the fuel would reduced from 2478 lb. per hr. 1489 per hr. the fuel consumption could maintained the original rate, the improved re- generator performance hypothecated the second ex- ample would increase the rate production per cent and reduce the full requirements per cent. These fig- ures are indicative trend only, since all this heat cannot used with known refractories. Air Infiltration One the most serious handicaps the maintenance high temperatures air leakage. excellently working open-hearth furnace there average drop temperature 500 deg. Fahr. the waste gases from the outgoing end bath the entrance the regenerative chamber. This due radiation from port ends and dilution the hot waste gas with cold air entering the furnace system. Dilution per cent commonly indi- cated analyses waste gases. This decreases the sensible heat nearly per cent. Effect Insulation Calculated heat balances uninsulated open-hearth regenerative chamber show the heat lost radiation from 13%-in. roof 1750 B.t.u. per sq. ft. per hr. increased roof thickness and proper insulation this The Iron Age, June 1929—155 “4 i N can reduced per cent the present loss. This would mean increase approximately 100 deg. the temperature the regenerated air going the fur- Insulation checker chambers has another value, the results which are often erroneously attributed in- sulation, and that the elimination leakage. Use Increased Regenerator Heating Surface the evolutionary development manufacturing usually stage which some radical from accustomed methods becomes necessary. This change comes the point where desired ex- sensible heat the waste gases below tem- perature 1400 deg. Fahr., and consists the abandon- natural draft for suction pressure produced mechanical means. processe: there departure tract the The introduction pressure and me- chanical draft heighten the effect leakage and make necessary sturdier and more carefully constructed cham- Mechanical draft enables the operator deliver the proper volume gas the furnace all times, and remove the spent gases. The loss draft with fouled checkers also greatly mitigated. Since would require almost 70,000 sq. ft. heating surface reduce the temperature the waste gas from coke-oven-gas-fired open-hearth furnace temperature 500 deg. Fahr., has been proposed supplement the fire-brick regenerators with steel alloys which will suc- cessively withstand continued heating temperatures 1500 deg. Fahr. the use these metallic substances effect heat transfer regeneration the cycle must extremely short. This combination fire-brick regenerator with long cycle reduce the temperature the waste gases 1400, combined with metallic regenerator with short cycle reduce the temperature deg. Fahr., together with the necessary fans will, course, introduce new complications the art making steel. will found impossible use all the waste gases the sec- ondary regenerator, since all the heat above 500 deg. were returned the furnace the resulting temperature type checker brick shown this drawing has been pro- posed improve regen- eration, either chang- ing the mass brick cubic foot space, in- creasing the free area per square foot hori- zontal checker area, reducing the cost lay- ing standard brick. Ad- vantages depend local conditions, such avail- able space, type fuel, method cleaning, and cost special shapes. equally well adapted for all conditions, Mr. McLoughlin’s opinion the flame would above the melting point the roof. Distribution Waste Gases and Air Chambers Studies distribution gas the checkerwork, one which shown the figure, indicate that faulty distri- bution even new chamber responsible for disap- pointingly low rate heat transfer. help correct this situation the distance from roof top checkerwork should decrease with increasing distance from the furnace end; opposite change should made the size the passages below the checkerwork. Thus uniform depth checker brick possible rectangular chamber, cir- cumstance which produces theoretically uniform draft the base each vertical opening. the new types regenerators number wells, ft. square, and from ft. deep, are left the top the regenerator checkerwork. the vertical side walls these there are number large open- ings, made leaving out number bricks, through which the waste gases may pass into the checkers when the top surface becomes sufficiently blocked with dust. This arrangement wells enables the furnace operator run for longer period before cleaning and gives higher temperature air toward the end open- hearth furnace run. Influence Reversal Period normal practice the time reversal left the judgment the furnace operator, and the cycle varia- tion ranges from min. about min. This often re- sults considerable unbalancing between the two ends and causes wide variation calorific intensity. not conducive either maximum production economy. For best results standard variation tem- perature preheated air should chosen and reversals fixed maintain these limits. This can done only fixing the temperature difference between outgoing gas and incoming air which reversal takes place. Metal Recuperators Favored For Old Furnaces OMMENTING Mr. McLoughlin’s paper, Con- way, fuel engineer, Lukens Steel Co., Coatesville, Pa., said that frequently impossible enlarge check- PETERSON = 1560—June 1929, The Iron Age PETERSON DANFORTH BRICK FURNACE END STACK Velocity Waste Gases Each Passage Open-Hearth Furnace Checker Chamber erwork the small cellars, under existing open-hearth furnaces. better average fuel efficiency then possible installing fans and reversing the furnace rule rather than guess. Incoming air constant pres- sure gives many theoretical and practical advantages, not least which come from the fact that such plan requires tight walls and insulation. possible also install recuperators made heat resisting metal the furnace temperatures will far more uniform, and the lag production experienced after campaign say 100 heats (due dust accumulation passages) can avoided great measure. Training Courses for Furnace Men Mr. Conway said almost hopeless attempt mathematical treatment checker design, for the therm- properties the brick vary with small changes its composition, with the quantity and nature the ad- hering dust (which turn varies with the furnace, whether acid basic, and the type fuel used). also emphasized the necessity educating the furnace men, asserting that series after-hours’ talks steel- making theory and practice, and furnace construction, illustrated scale models, had shown immediate and BRICK DANFORTH gratifying results speeding the heats and maintaining quality the Lukens steel plant. Miller, assistant superintendent open-hearth department, Inland Steel Co., Indiana Harbor, Ind., said that regenerators are now usually overloaded because the capacity the furnaces has been raised per cent increasing the hearth dimensions and putting more heat through the ports without any corresponding in- crease checkerwork volume. Efficiency the existing chambers can improved either reducing the amount excess air, giving the incoming air higher preheat. Air easiest controlled measuring volumes the fan, and the small excess necessary regulated the appearance the flame and the duration the heat. Waste gas analyses are unsuitable for such purposes; the criterion the necessity refine the bath promptly. Higher preheat may had adequate insulation (plastic materials are favored) and use metallic air preheaters, similar those used boiler stations. ample factor safety should used designing these recuperators, they