The Iron Age 1930-02-27: Vol 125 Iss 9

THE IRON New York, February 27, 1930 ESTABLISHED 1855 VOL. 125, No. Plant Handles Scrap Conveyors Motor Wheel Corporation, Producing Nearly 100 Tons Day, Effects Economies Equipment Which Crushes Turnings and Convéys Them Freight Cars the plant the Motor Wheel Corporation, Lansing, Mich., the installation conveyor systems that deliver scrap from the shop railroad cars. The plant produces about tons steel turnings and tons malleable iron borings day. Before the installation the conveyors the scrap was gathered wheelbarrows shop trucks the machines, wheeled the yard where the turnings were crushed and loaded cars hand. This Scrap Crushers Located Pit method required considerable Turnings fall conveyor in. wide, which dis- labor and proved source charges them into hopper over two scrap crushers located trouble. pit beneath. The hopper has swing gate With the building ex- that the scrap may delivered into either both tension the plant, the new crushers. From underneath the crushers 18-in. scrap facilities were conveyor carries the crushed turnings second provided. Extending the length conveyor in. wide which carries them under- the building through the cen- ground out into the yard and sufficient incline ter tunnel 400 ft. long allow them dumped into chute over the which two conveyor systems are side open top car. storage hopper located, one for turnings and needed because the output turnings suf- the other for borings. The con- ficient fill two cars per day. car spotted veyors are the steel apron beneath discharge hopper the morning, handling scrap have been effected with cross member supports which provide safe load 250 per sq. ft., which ample floor strength for loaded trucks. The batteries machines are located each side the tunnel. Scrap handled from the machines wheelbarrows and dumped the conveyors through hood-covered openings the floor. — Scrap Carried Conveyor 50-Ton Storage Hopper Located Side Railroad Track 631 . loaded noon and second car spotted during the noon hour filled during the afternoon. The conveyor for malleable iron borings, which in. wide, extends through the crusher pit and delivers the scrap cross conveyor. This carries the borings 50-ton storage hopper located the side the railroad track. The hopper equipped with hinged chute which after the car loaded lifted verti- TEEL Turnings Are Car- Hopper Over Two Crushing Machines Located Pit Underneath. The hopper has swing gate that scrap may delivered into either both crushers cally against the hopper side allow clearance for the removal the car. steel hopper was provided for this part the system because the quantity borings not sufficient load car without paying demurrage charges. stated that the saving demurrage charges year sufficient pay the cost building hopper. Construction Conveyor Permits Removing Worn Easily Two strands steel bar bushed roller chain with in. bedded apron pans are used throughout conveyor mediums. This type chain was selected most suit- able because simple construction and all wear confined parts which are easily removable. The side bars are made mild steel, the pins cold-rolled steel and the bushings seamless steel tubing. the pins and bushings are case hardened. The rollers are white 632—The Iron Age, February 27, 1930 iron and have internal lubrication. The bushings are milled flat the ends and are rigidly held the side bars being fitted into corresponding shaped holes. The pins are held the side bars malleable iron keepers, which, addition preventing rotation, hold the pins position laterally, thus dispensing with the use cotter pins and the same time providing chain which can easily dis- assembled. The apron conveyor carried T-bar rails which are supported proper intervals with floor CRAP Handled From the Ma- chines Wheelbar- rows and Dumped the Conveyors Through ered Openings the Floor frames which are bolted and grouted into the concrete the floor. The conveying equipment was designed and erected the Palmer-Bee Co., Detroit. Bureau Tests Structural Welds order help the construction industry obtain safe and economical structures, the Bureau Standards cooperation with the American Bridge Co. has investigated welded connections for steel-frame buildings. These in- cluded tests column splices formed welding plates the inside faces the column flanges. The connection was made bolting splice plates these welded plates. The tests showed that the connections were adequate strength carry the loads for which they were designed. 7 7 7 Galvanizing Pot Destruction Linking Theory and Practice—Overwhelming Influence High Temperatures—Study Resultant Alloys WALLACE IMHOFF* mind. advances, and opens new fields knowl- edge, and often not applied practical way for years afterward. The discussion here offered prac- tical research—that is, research done with definite view- point mind, and from the angle immediate practical application the knowledge obtained. discussing the theory galvanizing pot destruction, the knowledge submitted the result number years research work done the writer, determine the principles and laws involved the practical formation galvanizers’ dross, and galvanizing pot destruction. This leans toward the practical side theory, that is, theory which can used practice immediately, rather than theory that complex, mathematical and intricate, and which value practical way must unraveled, and applied some other investigator with practical viewpoint. research done with practical viewpoint From practical standpoint the theory galvanizing pot destruction built largely around two distinct lines investigation: The influence temperature its relation the contact molten upon iron (steel), and the dissolving action the molten zinc (the solubility the iron the molten zinc) different temperatures. Com- plete knowledge and appreciation this knowledge, and the proper practical application it, will greatly reduce the number failures galvanizing pots under practical conditions, Since there are also many other factors involved, such the composition the steel, its soundness, oxidation, segregation and mechanical defects caused rolling and fabricating, once seen that, even with this knowledge, the preserving and lengthening the life galvan- izing pots still not simple matter, but very intricate and complicated, since under practical conditions all the knowledge and principles combustion engineer- ing are involved also. This primarily the reason why more progress this field has not been made. has been thought that all that was neces- sary was buy pot, and build furnace around it. Such procedure, however, entirely ignores the defi- nite principles set forth this paper, with the result that pots fail three days, week, two weeks, six weeks, few months, *President, Wallace Imhoff Co., Highland Building, Pittsburgh. IG. 1—Commercial Slab Zinc with Steel Sheet It, Heated 800 Deg. Fahr., Held for Hr. and Allowed Cool Slowly. Mag- nified diameters (all seven cuts were re- duced per cent reproduction) These investigations cover mainly the two main phases galvanizing pot destruction, the influence tempera- ture, and the solubility the steel the They not cover variation the chemical composition the steel, but have reduced all variables minimum using one steel base for all temperatures. Other valu- ables, such oxidation, segregation, mechanical treat- ment, fabrication, have been purposely eliminated, also. For all practical purposes here, the melting point zinc 786 deg. Fahr. Since even the investigation the theoretical phase must limited the practical view- point, experiments were started with conditions which would give the relation first 800 deg. The purest com- mercial brand slab zinc used for hot galvanizing was used all the tests. was obtained from galvanizing firm using this quality and brand metal for regular gal- vanizing practice. analysis this shows: Complete Analysis Commercial Zinc (Iron (Iron Precipitation) Titration) 99.7984 *By The iron content was low that was exceedingly difficult obtain the correct amount either method. The pieces sheet steel used the investigations were in. square, gage, O.P.C.R. sheets the standard analysis for this material. analyses were made the steel, since was standard stock. Tests Made Eight Progressive Temperatures All samples the test were within 0.1 gram. The were made the following temperatures: 800 deg., 850 deg., 900 deg., 950 deg., 1000 deg., 1100 deg., 1300 deg.. and 1500 deg. Fahr. The tests were conducted accurately controlled elec- tric furnace, with pyrometer and all instruments necessary give accurate control and definite knowledge facts and conditions. soon the zinc was melted and the proper temperature, the iron sheets (pickled clean) were placed the container. This was the purest material, con- taining absolutely source iron other material which would dissolve and contaminate The Iron Age, February 27, | 7 IG. 2—Polished Surface Directly Under the Steel Sheet Fig. Melt 800 deg. and conditions same Fig. di- ameters the zinc. The furnace temperature was then held the constant required temperature for hr. This ended the test. The switch was then drawn, and the container was allowed cool slowly with the furnace until cold. (Over- night, each case.) the morning the container was removed and the contents weighed within 0.1 gram discover there was any loss through evaporation the zinc. close check the tests indicated there was appreciable loss from this cause. 800 deg. Fahr. the zinc had melted and was stuck tightly the iron sheet; there were some scum, dirt and oxide top the melt; the melt was removed easily from the container. 850 deg. the zinc had melted evenly around the steel sheet; there were scum, dirt and oxide top the zinc. IG. 3—Commercial Slab Zinc with Steel Sheet Heated 850 deg., Held for Hr. and Allowed Become Cold. diameters 634—The Iron Age, February 27, 1930 900 deg. the zinc was discolored purple and blue oxide; the steel sheet was covered with deep, dark brown-bronze oxide iron. 950 deg. very visible action the zinc and iron could seen. 1000 deg. the melt was covered with brown and blue oxide scum, and cone-like deposits were seen against the steel sheet. 1100 deg. the melt had greenish tinge; yellow- bronze zinc oxide and scum were the top and there was gorgeous array colors light yellow-green and pur- ple near the steel sheet. 1300 deg. there was green zinc oxide over the melt. The top the steel sheet crumbled and broke away from the sample. 1500 deg. the melt was again covered with olive green oxide. The top the sheet crumbled and was easily lifted out the melt. The conclusions seen far from the rough examina- tions the melts all tests are that there not 4—Polished Section Directly Under the Stee! Sheet Shown Fig. di- ameters appreciable loss the zinc evaporation, but there considerable oxidation the zinc the higher temper- atures. Study the Results Obtained particular interest see what really happened all these tests. this the samples were all cut, etched and specially prepared for examination under the microscope. With very high magnification the relation the whole often lost interpreting results; with very low magnification important things are not seen. The present series tests was standardized magnification diameters for all samples. This large enough bring out the facts, and still not obliterate their relation the whole. Fig. shows the melt after subjecting the steel sheet the action the molten zinc 800 deg. Fahr. for hr., and slowly cooling the furnace overnight. The section right angles the sheet, and the magnification diameters. The first feature particular interest the large, clear crystals zinc. The boundary line between two these crystals can seen about one-third the | 7 7 7 7 . } ~ 4 ‘3. a 7 | ‘ > way down the left side the plate. The right side the plate all one large zinc crystal. These crystals not contain any foreign matter when viewed under low magnification, but are entirely uniform and homogeneous throughout. Under high magnification the crystals contain black specks, but these are small that not even the crystal form the zinc-iron alloy can recognized. important note the general condition the the melt around the steel sheet. Under low magni- fication there seems practically penetration the iron into the zine crystals. Between the zinc crystals and the steel sheet there alloy bond. This consists two distinct bands; dark iron-zinc band near the steel sheet, and lighter zinc-iron alloy band next the zinc crystals. Passing from one the other there the steel sheet, the dark iron-zine alloy band, the light zinc-iron alloy band and the zinc crystals. This calls attention the fact that the relation between the two such that where the iron excess the alloy iron-rich alloy, and where the zinc excess, 5—Commercial Slab Zinc with Steel Sheet Heated 900 deg., Held for Hr. and Allowed Slowly Become Cold. diameters the alloy zinc-rich alloy. The dark iron-rich alloy the more brittle the two. This seen the large crack (the thin white streak the plate) made when sawing the specimen for examination under the microscope. Under high magnification the light alloy next the zine crystals found contain very small dross crystals floating the zinc-iron alloy. Also, outside these crys- tals, and next the zinc, there irregular black material which appears dross crystals, but even with the high magnification the individual shapes the dross crystals (zinc-iron alloy) cannot made out clearly. The dark, iron-rich, iron-zine alloy wider than the light zinc- iron alloy. Two Separate Alloys Are Formed Later investigations have shown that all the alloys are really alloys, but distinguish the types alloys they will for convenience here called zinc-iron alloys when high and low iron, and alloys when high iron and low zinc 6—The Zinc-Iron Alloy from Galvanizing Pot Destroyed Under Practi- cal Conditions Operation. The crystals can seen breaking and floating away into the bath. diameters content. The feature importance here note that there are just two zinc-iron alloys formed, one next the steel sheet and one next the zinc. ascertain more the action the zinc upon the steel the sheet was pulled out the melt, and the surface the melt directly under the steel was polished that could examined under the microscope. Fig. shows this surface directly under (or beside) the steel sheet. important see that the alloying action (the dissolving the iron the zinc) begins low temperature 800 deg. Fahr. Note the two large alloy spots showing the beginning the transfer the iron into the zinc. The zinc area seen above and below these two alloy spots. might stated that the sample had polished and etched very lightly that little possible this thin alloy bond would removed. Attention called also the fact IG. 7—Polished Surface the Melt Un- der the Steel Sheet Shown Fig. diameters The Iron Age, February 27, 1930—635 : E . 7 5 7 * that the iron has not penetrated the zinc melt any great depth. This fact revealed the areas found inside these alloy spots. Fig. shows the steel sheet the melt deg. for hr., and then slowly cooled. The section across the sheet. The magnification diameters, the same particularly interesting compare the action the molten zine under identical conditions except for the deg. increase temperature. The clear, beautiful, medium-sized crystals zinc can seen plainly (by moving over the entire field). Under low magnification these crystals seem absolutely clear any foreign matter. Even with high-power objective the zinc crystals are found remarkably free from foreign material, any material which resem- bles dross alloy), except for the black specks, which are very small. distinct dross crystals can seen. The condition the steel sheet appears much the same 800 deg. Under low magnification there seen very little penetration the iron into the zinc (iron dissolved the zinc). The alloy bond between the zine crystals and the iron sheet seems about the same width. Under high magnification the dark iron-zinc alloy next the iron sheet seems breaking into dross crys- tals, which are floating the lighter zinc-iron alloy. The light alloy, which was the thinner the two, and next the zinc crystals, has now extended clear over the iron sheet, and large pieces the dark iron-zinc alloy are floating dross crystals. Note how the width the zinc-iron alloy (compared with Fig. has spread and widened the bottom the sheet. Fig. the polished surface directly under the steel sheet shown Fig. The iron has alloyed with the zinc all these crystals the same shown Fig. When examined under higher power magnification, the crystals all show alloying action the zinc and iron. The alloy found also between the crystals. Active Action Begins 900 Deg. Fig. shows the effect commercial slab zinc with steel sheet heated 900 deg., held for hr., and allowed cool slowly. Again magnification diam- eters. This specimen exceedingly interesting, showing that the alloying action the molten zinc has now become exceedingly active. Particular attention once called the increased thickness the iron-zinc alloy next the sheet. Also note that the zinc-iron alloy the zinc area much wider and has lost its regular outline. Farther away from the steel sheet the zinc melt seems less affected. The large, clear, unaltered, uniform crystals the zinc can seen plainly moving over the field. Under low magnification these crystals appear entirely free from foreign matter any kind. Even under high magnification traces zinc-iron alloy dross crystals are seen back the zinc area the melt. The area immediate contact with the steel sheet, however, presents interesting features for discussion. Un- der low magnification there seen comparatively little penetration the iron into the zinc area. The alloy bond alloy) can seen considerably wider and, the side next the zine (zinc-iron alloy), count- less small crystals dross are ready float off into the zinc. Under higher magnification these tiny dross crys- tals are seen have penetrated the zinc area consider- able distance from the iron sheet. the bottom the sheet the zinc-iron alloy flared out for considerable distance both sides, and seen composed orderly arrangement dross crys- tals which are tending separate and float off individually 636—The Iron Age, February 27, 1930 into the zinc area. These dross crystals are arranged right angles the steel sheet. few dross crystals are seen which have broken away and moved far out into the interior the area. Greater Dissolving Iron Noted The particular feature interest note 900 deg. Fahr. the increased penetration the into the iron; or, stated reversely, the increased dissolving the iron from the steel sheet. The mechanism destruction here revealed. follows: the iron first dissolves into, alloys with, the zinc iron-rich (high iron con- tent) zinc-iron alloy. This iron-rich alloy disintegrates into smaller fragments, dross crystals, which later break into still smaller fragments they float off into the melt. The whole action destruction seems exactly parallel ice breaking from pond the winter— the large cakes ice breaking into smaller cakes, and finally dissolving the water they float off into the clear area. This, then, the mechanism the destruc- tion, and this same action takes place the destruction large steel galvanizing pots under practical operating con- ditions. Fig. shown exactly the same disintegration the heavy zinc-iron alloy the left the plate. This alloy from the side the 16-ft. galvanizing pot de- scribed detail THE IRON AGE, Jan. 23, pages 294 297. section ft. square around the hole was cut out the firebox steel side the pot after failed. Fig. shows the iron-rich zinc-iron alloy next the firebox steel side the left the plate. The alloy can plainly seen disintegrating, and the crystals are floating off into the bath the right the plate. This process con- tinues until complete destruction the pot brought about. Fig. shows the polished surface the melt under the sheet shown Fig. The particular feature in- terest this plate the thickness the alloy bond. The zinc-iron alloy (iron-rich) shown the opaque area the right the plate. Directly through the center vertical direction line, area, about in. wide, the actual thickness this alloy. the extreme left the melt seen with alloy crystals it. This illustration seems bring out the fact that the alloy bond nothing more than layer orderly ar- ranged, closely packed, dross crystals. The dark area alloy the right shows these crystals orderly arranged into unity—a solid, continuous area. the area the melt the strong enough break this unity and the crystals float off dross crystals. (To continued) Turbo Blowers Have Chromium-Nickel Blades turbo-blowers, built Brown-Boveri Co., have been installed German blast furnace plant. 2900 r.p.m., each draws 2360 cu. (83,300 cu. ft.) air and raises the pressure 2.5 atmospheres (37 per sq. in.), the power required being 8150 hp. the furnace hangs, the pressure can raised 3.25 atmospheres per sq. in. (2620 cu. m., 92,500 cu. ft. air, 3200 r.p.m., 11,500 hp.). The turbine blades are made chromium- nickel steel, having tensile strength 110 kg. per sq. mm. (156,000 per sq. in.); yield point kg. per sq. mm. (107,000 Ib. per sq. in.); elongation per cent, and notch test value kg.-m. per sq. cm. (374 ft.-lb. per sq. The steam turbine will take steam temperature 400 deg. and atmospheres (500 lb. per sq. in.) pressure. | | 7 | 7 1 7 | Foundries Use Gas for Annealing Heating Period Shortened New Furnace—Savings Compared with Other Fuels—Even Heat Distribution PHILLIPS* general tendency the metal industry today toward alloy steels, and this trend exerting decided influence the process annealing cast- ings. fact, the opinion some that the term annealing will eventually become obsolete and that foun- ders will called upon furnish heat treated castings. Already these founders are demanding more modern and reliable annealing equipment, that will impart the correct grain structure the castings and produce the physical characteristics specified the customer. After many trials the car bottom type furnace became the accepted design. Coal and oil were tried and aban- doned, and then, for good reason all, electric furnaces became the style. Economic pressure, however, forced the hand the foundry industry and gas-fired furnaces made their advent and with startling result. was soon proved that roughly per cent saving was made with gas over electricity, and this with the latter per kw. and gas 530 B.t.u. selling for per 1000 cu. ft. Economies effected included: decreased cost for fuel; shorter heating and hold- ing periods; more uniform bution; exact atmos- control; and the ability produce the proper furnace pressure and maintain automatically throughout the entire heat gradient. ad- dition lowering the fuel costs, the use this furnace increases production and cuts the labor item, while the same time better product results. further increase output with still less unique material han- dling system. The first these units was installed the plant the Link Belt Co., Chicago, known nationally and internationally for its — *Vice-president, Sur- face Combustion Co., Toledo, Ohio. OOKING into Gas-Fired Car Bottom Annealing Furnace with Loaded Car Position conveying machinery all types. The Chicago plant this company self-contained from raw material fin- ished product. makes its own steel 2-ton, side blow converter, with capacity for blows per day. The steel most commonly used the following analysis: Carbon, 0.30; silicon, 0.35; manganese, 0.75; phosphorus, 0.03, and sulphur, 0.035 per cent. Car Bottom Type Used The gas-fired, bottom type furnace used this plant for annealing castings was developed, over period years, the engineering and research staff the Surface Combustion Co., Toledo, Ohio. has door each end and track running through it, which the cars castings are pushed into and through the furnace. This furnace 10% ft. wide, ft. long and ft. from the tops the piers the crown the arch. holds one car, ft., and will anneal 14,000 castings charge. The walls are com- posed in. fire- brick and in. insulation, backed with reinforced steel casing, while the whole structure tied together with double channel buckstays and tie rods located suitable intervals along the sides, front and back. arch thrust member runs the full length the furnace each the springline the arch. The fronts are heavy cast iron plates, suit- ably ribbed, and held Shortening the heating periods was using the standard high pressure gas the Surface Combus- tion system. There side, staggered heat the work both from the top and bottom. These burners are The Iron Age, February 27, | | 4 7 Gas-Firing System Car Bottom Annealing Furnace for Steel Iron Castings two types, one set being the holding burners and the tunnel type, manifolded proportioning inspirators, while the others are separate, two-stage velocity burners for heating up. These latter burners are shut off when the furnace temperature and thereafter the holding burners are kept operating low rate means reg- ulators and check valves by-pass line. The gross weight the charges used this unit vary from tons and the heating cycle from hr. and min. Practice this plant heat the steel castings 1750 deg. Fahr., which, stated, takes from about hr., and soaking this temperature for another hour. The burners are then all turned off and the charge withdrawn for cooling. Iron castings are annealed 1250 deg. Fahr., but instead cooling the air they are allowed cool the fur- nace. This cooling cycle can accelerated any rate progressively dampers, more which later. Temperature automati- controlled, the equip- ment consisting two sets controllers with front dial settings, one set taking care the upper burners both sides and the other set the lower burners both sides. Motor operated control valves, interconnected with thermocouples and recording pyrometers are provided, and this arrangement allows for the automatic shutting off the main heating burners, when the furnace has come heat, after which the holding burners are controlled from the by-pass line mentioned above. The feature two-stage inspiration applied the high pressure velocity burners practically eliminates the back- fire flash back which oc- Drawing Car from Furnace with Winch Extreme Left 638—The Iron Age, February 27, 1930 curs low rates gas con- sumption, with the standard high pressure equipment. The specific operating range for this new apparatus has This wide range allows one burner used where two were required before with the old type and applica- tions where wide turndown was necessary. Infiltration cold air from the outside eliminated the gas furnace because the gas and inspirated air for combustion are forced high pressure, thus creat- ing pressure the furnace which offsets the stack suc- tion. The flues for venting the products combustion are located near the tops the piers and pass through the side walls into two com- mon ducts running the full length the furnace each side and then across, close the front the furnace, common outlet stack, which closed with gas cylinder operated damper. 4 - an — _ a 4 — ‘ 4 When the main heating burners are closed, naturally the positive furnace pressure lowered and becomes neg- ative because the stack pull. offset this, the damper closed the correct amount the forward movement the cylinder piston. This motion made automatic the piston controlled means the gas pressure the main gas line and the furnace side the controller and control valve. Therefore, when the gas pressure shut off this line entirely, the valve acts close the damper. control, necessary for scale elimina- tion, obtained and automatically maintained the use venturis gas-air proportioning devices. With these any desired atmosphere can had, but, course, this case slight excess gas used. Further than this, high degree efficiency assured that the mixture can regulated for complete combustion, the gas being entirely consumed the When annealing castings this plant continuous cycle used, and, order shorten the charging and discharging periods, two cars were fastened together, per- manently, with spacer bar. When the first car charge has been annealed, the furnace doors are raised and the car withdrawn, the other, which has been loaded the meantime, pulled in. The doors are then lowered and the heating process starts again. This operation charging and discharging requires less than minute and during this time the temperature drops from 1750 approximately 1700 deg. Fahr. Pre- vious this innovation, from min. were necessary and with temperature drop 850 deg. Fahr. This hooking the two cars together reduced the heating period materially and effected considerable reduction fuel con- time passes out the combustion ports used 530 B.t.u. and delivered the plant from in. water pressure, but this pressure raised lb. recip- rocating compressor. and into the heating chamber. The gas Hot Products Combustion Recirculated Localization heat, spots strata, has always been factor some concern periodic furnaces regardless the fuel employed. This has been entirely overcome this new unit means the positive recirculation the hot products combus- tion together with the system staggering the burners that they fire from both above and below. Furthermore, alloy steel frames with light holes rest the car top and the work piled these and such manner that spaces between the individual pieces are left. the lower bank burners fire opposite these light holes, the heat circulated and recirculated through- out the furnace and over every square inch the surfaces the castings being treated. the combustible gas-air mixture forced through the burners under pressure, the positive, complete and contin- uous. The car tops form the hearth and thus divide the furnace into two parts, the upper which the heating chamber and the for the trucks operate in. sand provided each side and end the car which prevents. heat from leaking down through while ports the side walls the furnace, and below the car top, let cold air which keeps the wheels, truck and frame cool. Ease Charging and Unloading Sealing the heating chamber from the outside cold air accomplished fitting the doors each end into sand seals the floor the car. These doors are cast iron ribbed construction, lined with insulating concrete and are motor operated. Sheave wheels and counter weights are provided, the sheave wheels and brackets being mounted brackets structural steel members over the doors. The car tops are constructed heavy steel members and lined with in. firebrick and in. insulation. The brick- work corbelled over protect the steel frame the car from the heat. The car moving mechanism consists air winch and endless steel cable passing through recess the floor and through the center the furnace and suspended sheave the opposite end. Chain rings are fastened this cable and these engage hooks the car. Charging Car with Hoist and Monorail Conveyor sumption. overhead monorail system with two hoists and serving both ends this furnace makes possible load unload either both ends. Some Cost Comparisons Formerly this company used oil-fired furnace and bought oil 4.6c. gallon, delivered tank cars. Fig- uring the cost unloading, operating and maintaining carrying lines and auxiliary equipment, together with oven maintenance, arrived the following costs: exhaustive report was made the annealing situ- ation which were detailed all the weaknesses oil- fired furnaces against the strong points the gas-fired unit together with the fuel costs, etc., and was this page 692) The Iron Age, February 27, 1930—639 | Indiana Harbor Merchant Mills Two New Units Chicago District Have Three Open-Hearth Furnaces 250 Tons—Full Range Bar Sizes new merchant mills advanced design are being completed the Youngstown Sheet Tube Co. the Indiana Harbor works. Their products will include the full range merchant bar sizes, and will overlap into the smaller structural shapes. Two producer-gas-fired continuous furnaces, into which billets sizes in. square will charged, serve the larger mill, which consists two stands 24-in., five stands 18-in., and four stands nominal roll diameters. ingenious grouping roll stands and cooling beds, has been possible provide two outlets the mill, one from the last 18-in. stand and the other from the last 14-in., each delivering its own cooling bed. Primarily this 14-in. mill, but the arrangement just mentioned has widened the range products include sizes ordinarily covered 18-in. mill. The layout per- mits rapid changing sections within the full range, and this great advantage, not only the operators, but also the customers, who can served with greater variety products the shortest possible time. Smaller Mill Has Stands Served 30-ft. continuous furnace, taking billets from in. in. square, the smaller mill consists stands rolls having nominal roll diameters in., in. and in. Ordinarily, when rolling merchant bars, only stands less will employed, delivering bars either the cooling bed the reels. these stands four more stands can added, thereby converting the merchant mill rod mill capable rolling No. rods. This combination will give the mill range from No. rods 1-in. rounds, and other sections such squares, hexagons, flats, etc., equivalent weights. All sizes rounds, squares and hexagons can fur- nished coiled, bundles weighing from 150 900 depending size, but only those sizes down %-in. Continuous Billet-Heating Furnace and Five Stranding Roll Sets the 10-In. Continuous Mill 640—The Iron Age, February 27, 1930 rounds will delivered the cooling bed. feature the mill that No. rods can furnished bundles any desired diameter and weights 450 Ib. obtain bars unusually fine finish extensive hydraulic system has been provided both mills, for the purpose removing scale spraying the bars while process rolling. There are also appliances insure the proper predetermined finishing temperature and greatest possible accuracy size. The cooling beds have been de- signed with view delivering exceptionally straight bars the shears, thereby making possible, normal cases, furnish product acceptable the customer without additional charge for cold straightening. The cooling bed the 10-in. mill provided also with pack annealing ar- rangement for spring flats and similar products. Maximum Daylight for Inspection the shipping department, which ample size, special effort has been made obtain the maximum amount light, which importance make certain the proper inspection material. this department are also installed straightening machines, cutting-off machines, cold saws and other appliances which may required preparing the rolled material any manner desired the customer. The plant was designed the Morgan Construction Co., Worcester, Mass., who also built the gas producer plant, furnaces and all rolling mill machinery. The West- inghouse Electric Mfg. Co. furnished motors and con- trols for the main drives, and the General Co. supplied all auxiliary motors. The buildings, designed and built the Hansell-Ellcock Co., Chicago, and the Truscon Co., Youngstown, have over-all length 1650 ft. and width 324 ft. There are three parallel main buildings, the center one containing the billet storage one end, and the finishing and shipping departments the 18-in. mill the other. the two outside buildings are located the gas producer plant, heating furnaces, rolling mills, cooling beds, finish- ing and shipping departments. One building contains the 10-in. mill and the other the 14-in. mill and the 18-in. mill, except finishing noted above. Total area under roof acres. The plant expected produce 300,000 tons bars year. provide the additional steel tonnage, open-hearth capacity being augmented the addition three 250- ton furnaces the present plant, which consists one 250-ton and three 130-ton furnaces. the intention retain the three smaller furnaces for special steel. This arrangement, with already existing facilities for making Bessemer steel, provides adequate means for production the many grades steel de- manded makers bars. Other expansion necessitated the building the merchant mills are two new soaking pits, new motor- generator set for the blooming mill motor, and new 10- stand continuous billet mill for rolling billets sizes from in. in. square. While the 10-in. mill already operation, not expected that the whole program will completed before April. Large Gain for Manufactured Gas Used for Heat Treating Large-volume users manufactured gas, furnished Peoples Gas Light Coke Co., Chicago, have doubled number the last five years, according Mullaney, vice-president. “The Peoples company has supplied upward 6,000,- 000,000 cu. ft. gas 1929 for strictly industrial purposes, most for the heavy duty heat-treating processes modern industry. This outlet, which has been consistently pushed for only about years, now accounts for practically per cent the total output. “In August, 1929, the company added metallurgical and research laboratory its facilities for promoting in- dustrial use gas. The purposes this laboratory are: first, assist customers locating and correcting any difficulties their heat-treating operations; second, ob- tain specific information upon which base recommenda- tions designs gas-fired furnace equipment; third, search for fundamental scientific knowledge which must obtained improve manufacturing processes and broaden the usefulness gas the community. This laboratory second none the country. equipped deal with every kind heat-treating problem arising connection with temperatures from 100 deg. 2900 deg. Fahr.” — Finishing Stands the 10-In. Mill. Haze, right, beyond mill was caused heat waves from hot bars The Iron Age, February 27, 4 fff | Sintering Limonitic Ores Commercial Application Required Reduction Costs— Enlarged Machine Solved This Problem—Flexible has become standard practice treat iron blast furnace dust either the Greenawalt Dwight-Lloyd machine, that can recharged into the furnace. The mining low-grade magnetite iron deposits and their beneficiating grinding and magnetic separation re- sults fine concentrate extremely detrimental blast furnace practice. These concentrates are sintered and made into ideal material for furnace use. The application li- monitic iron ores the most recent development the sintering process. The first plant the Lake Superior region was erected the Minnesota Sintering Co., subsidiary the Evergreen Mining Co., Ironton, Flow Sheet PERRY HARRISON* rebuilt during the winter 1928-29, with most satisfactory results, in- dicated Table Ore, fuel and fine sinter screened from the discharge the sintering machine are conveyed the collector conveyor elevator and raised the top the sintering plant, where they are discharged into drum-type pug mill especially designed handle the sticky, abrasive material treated this plant. the pug mill, the ore, fuel, return sinter and some ad- ditional water are mixed the con- sistency required the sintering op- eration. The discharge from the pug mill spouted the head end the sinter- ing machine through swinging spout and hopper, which allow the material being delivered the machine fall over inclined surface material previously delivered, that the coarse material may segregate out toward the bottom the sinter bed. The moving sinter bed carries the mix- ture ore, fuel and returned sinter three ignition furnaces. Ignition and Travel Burning Zone Each furnace covers the width the bed and burns gas obtained The plant was designed treat Phos- Man- Loss, Moisture ifer- Iron. phorus, Silica, ganese, num, ss, Moisture, Cuyuna Range iron and manganifer Per Per Per Per Per ous ores containing low silica, high Tons Cent Cent Cent Cent Cent Cent Cent moisture and structure objectionable plant 249,796 0.275 8.76 1.09 4.04 7.61 because large proportion fines. Natural ...... 44.95 0.233 0.92 342 644 15.32 Ores this quality constitute shipped... 192,477 proximately one-half the ore re- Dried 948 119 1.15 serve the Evergreen mine. Natural ...... 58.89 0.320 9.43 1.18 5.20 1.14 0.50 Extraction 5.8 97.9 98.8 7.2 Until 1928 operations this plant Theoretical value crude ore (too low were largely the experimental state grade actually sell): prices about the time the plant was ready $3.53 ready for operation and the Freight $1.74 stricted demand for ores for the next years, sufficient outlet for the plant Sinter value 58.89@0.08738........... $5.15 1.79 Freight 3.36 was not obtained demonstrate whether not sintering had com- mine value due $1.62 this plant produced 115,000 tons iron and manganiferous sinters Iron, phorus, Silica, ganese, num, Dwight Lloyd machine, size in. Tons Cent Cent Cent Cent Cent Cent Cent ft. Sufficient information was ob- plant 27,216 that operating costs machine shipped... 19,659 Gain prices current during that year, were 72.2% Satisfactory reduction sintering ural analyses 135 0.03 costs had been obtained, however, crude ore (too low both Buffalo and Chateauguay the grade sell) replacement 42-in. Dwight-Lloyd sintering machines machines with these results, and estimated sav- ings calculated the operators the Evergreen plant, was Ironton, Minn. Abstract paper Institute Mining and Metallurgical Engineers, New York. Iron Age, February 27, 1930 | treating preheating retorts oil deg. gravity. Ignition the solid fuel the upper portion the bed material takes place under these furnaces and the burning zone gradu- ally travels downward through the bed under the influence downcast draft air drawn through the bed Buffalo forge Co. fan, which fur- nishes 60,000 cu. ft. minute and vacuum. the time the material the bed has traveled ft. and reached the discharge end the machine, the zone burning and incipient fusion— e., sintering—has burned completely through the bed. The finished sinter, ranging size from fines large chunks ft. wide ft. long and about ft. thick, drop off the bed and discharge grizzly made railroad steel set in. apart. There any fine sinter unsintered ore drops through into the bin for return sinter and the coarse material spouted into railroad cars, which are protected from the red hot material water sprays arranged cool the part the material close the sides Table Results Evergreen Plant SINTER PRODUCTION Tons Tons per Effective Hours per Actual Hours GrateArea, Square Foot Year Tonnage Operated Operated Square Feet Grate Area 15,784 921 17.14 224 1.84 19,794 1,038 19.07 224 2.04 115,546 5,054 22.86 224 2.45 213,022 4,826 44.14 452 2.34 AND LABOR EFFICIENCY COMPARISONS Per Ton Tons Sinter Sinter per Man-Shift 1928 in. ft. sintering machine.............. $0.2179 11.86 1929 ft. sintering machine.............. 0.1443 16.77 The flow sheet the plant ex- tremely flexible. Ore delivered the plant can treated follows: (1) can simply crushed and reloaded into railroad cars; (2) can crushed and the fines screened out and sintered while the coarse loaded for shipment direct, washed and the coarse material, reduced silica and moisture, can shipped; (3) the entire crushed and washed; (4) the entire ore can crushed pass mesh and sintered. This a the car. wide flexibility makes possible the CHAIN GRIZZLY UNDERSIZE OVERSIZE HOPPER HOPPER 30° INCLINE CONVEYOR (WEIGHTOMETER) CENT. PUMP CENT PUMP HOPPER BURNERS = — m MAT DUST COLLECTOR A SOLID OVER FLOW PUMP TAILINGS COLLECTOR CONVEYOR PIPE LINE | OORR-DAVIS WASHER CONCENTRATES TAILING GRIZZLY UNDERSIZE OVERSIZE 2-HOPPERS CHUTE 2 FEEDERS RR CARS Flow Sheet, Evergreen Plant beneficiation greatly varying types ore. Metallurgical Results 1929 The metallurgical results obtained ore put through the sintering pro- cess during 1929 are shown Table II. Sinter produced the Ever- green Mining Co. very coarse, but ft. loading from dock boat, which breaks down the large lumps and leaves firm, rugged product which will not break down further under load, although still retains cellu- lar and porous structure, which, like coke, permits the free and uniform distribution and passage furnace gases, with consequent good reduci- bility and freedom from hangs and slips the blast furnace. Although both cellular and porous, Evergreen sinter, being vitreous, will not absorb water and therefore will not freeze stock pile. interest- ing example this was the loading, subzero weather, the last boat leave the head the lakes with sinter this year, less than three hours. Cost Sintering Iron Ore compared washing, wash- ing and jigging, iron ores, the sin- tering process expensive. The ap- plication the process limonitic iron ores the Evergreen Mining Co. too new establish cost structure which can expected permanent. This evidenced the fact that the cost sintering was plant, capacity and methods from 1928 operations 1929. extensive program plant improvement and enlargement scheduled for the current winter was put through the last winter, in- cluding lengthening the sinter ma- chine 127 ft., which will result 762 sq. ft. grate area, machine one-third larger than the largest 96- ft. sintering machines now being erected the Bethlehem Steel Cor- poration. Despite all accomplished and hoped for cost reductions, the process likely have its application confined ores which, reason structure analysis, are difficultly merchant- able their natural state and which are unsuitable water concentration The Iron Age, February 27, 1930—643 7 ELEVATOR BUCKET ELEVATOR SWINGING CHUTE SINTERING MACHINE because the fines are high iron. Effective beneficiation iron ores the washing process can accom- plished only with ores which the fines, being the bulk the material removed, are high silica and low iron. The field for sintering, however, remains fairly large, particularly ap- plied ores under the disability double unit penalties which freight costs per unit metallic ma- terial are high. Reduction the Burden the Shaft Joseph the United States Bureau Mines that the use sinter the charge blast furnace produces change volume within the furnace, because the porosity the sinter. This makes material change the size the ore charge. There has been careful study made, Mr. Joseph said, within the past few years, for the purpose improving the operation the upper per cent the height blast furnace. reported that observa- tions blast furnace Utah showed that per cent the ore had already been reduced the time the burden reached the top the bosh. similar determination that only per cent the ore had been reduced this point. furnace the Chicago district, operating Lake Superior ore, was found have reduced only per cent the ore the top the bosh. Reclaiming Steel Foundry Recovery Per Cent, Much Lower Cost Than New Sand and High Uniformity FTER trying out, scale, several types reclaiming appa- ratus, was found that the combina- tion muller-type sand mill and air classifier followed dust collector gave the best results. Results from experimental unit indicated that recovery more than per cent could attained and that the reclaiming refuse sand should prove highly profitable. the basis these tests full-size unit was designed and installed. The schematic diagram shown should give clear idea the type apparatus used and method operation. There are, course, details which contribute the successful operation the plant, but which have not been shown because they would complicate the diagram and are not necessary for understanding the prin- ciples involved. typical week’s *From paper 19, the annual meeting New York, the American Institute Mining and Metal- lurgical Engineers, Dierker, re- search engineer, Ohio State University, from Cleaning Pit Centrifugal Dust Pulley Storage Sand Refuse Bin Device Muller type Hopper ----. Feed Belt Separator. Table Analysis Reclaimed Sand Sieve Per Cent Number Retained Cumulative None None 0.27 0.27 0.91 1.18 1.60 2.78 10.65 13.43 40 51.82 t ».25 26.61 6.66 98.52 100 0.79 99.31 140 0.24 99.55 200 0.06 19 61 —200 0.10 $9.71 operation this plant showed the following: Refuse sand treated, 1,177,700 (100 per cent) Good sand recovered, 1,005,800 (85.4 per cent) Table gives the mechanical and Table the chemical analysis the good sand recovered. will noted that the undesirable elements are con- centrated the finer materials, which are largely removed the classifier, Cloth Screen Collector Good Sand Exhaust Fan- Schematic Diagram Sand-Reclaiming Plant Iron Age, February 27, 1930 Table Analysis Fractions Reclaimed Sand Retained Screens Per 100 140 200 —200 Mesh Mesh Mesh Mesh Mesh Mesh Water ... 0.40 0.38 0.60 0.74 1.04 1.81 Carbon 0.66 0.90 1.74 2.70 4.00 97.46 95.38 91.60 90.74 86.46 80.14 .... 1.18 2.47 8.48 4.12 6.85 10.29 .... 0.10 0.06 0.69 0.61 0.74 0.71 0.36 0.52 1.48 2.05 3.12 GaO ....Trace Trace Trace Trace Trace Trace MgO ....Trace Trace Trace Trace Trace Trace Not determined Not determined Total ..99.96 99.71 99.30 100.00 100.12 100.07 leaving only the small percentages shown the good sand. Operation this plant for several years has proved that refuse sand can reclaimed fraction the cost new sand. Furthermore, castings poured into molds made reclaimed sand mixtures are equal every re- spect those poured into molds made sand mixtures containing all part new sand. fact, sand re- claimed this manner much more uniform quality than any ordinary grade new molding sand. This uni- formity, together with the fact that free from moisture, makes ideal sand for use the production shop where close control the sand quality imperative. Centennial Fairbanks Platform Scale Nineteen thirty marks the one hun- dredth anniversary the invention the platform scale Thaddeus Fair- banks, says announcement Fair- banks, Morse Co., Chicago. The many thousands special weighing machines used every industry, from meat packing aircraft manufacture, are all descendants this platform Thaddeus Fairbanks’ invention came about from the necessity finding way weighing hemp. that time Thaddeus and his brother, Erastus, had wheelwright and foundry busi- ness St. Johnsbury, Vt., and when the hemp cra