The Iron Age 1940-02-22: Vol 45 Iss 8

VAN DEVENTER President and Editor BAUR Vice-President and General Manager Managing Editor News Editor Editor Emeritus Machinery Editor Art Editor Metallurgical Editor Associate Editors Washington Fditors Resident District Editors . Pittsburgh Chicago Cleveland Detroit Fditorial Correspondents Lendon, England Cincinnati Boston Hamburg, Germany Milwaukee San Francisco Toronto, Ontario Birmingham 6 February 22, 1940 Leroy ALLISON Roy Newark, N. J. St. Louis TURNER, JR. Buffalo Monuments Live Ones Theory and Practice Slag Control DIX, Manager Reader Service Gating and Feeding Castings ADVERTISING STAFF Grinding Hardened Gears B. L. Uerman, Chilton Bldg., Phila. H. K. Hottenstein. 1012 Otis Bidg., Chicago Leonard, 239 39th New York Electric Ovens and Bicycle Production Peirce a, 7310 Woodward Ave.. Detroit C. H. Ober. 239 W. 39th St., New York D. C. Warren, P. O. Box 81, Hartford, Conn. Don F. 1595 Pacifie A Member, Audit Bureau of Circulations . Member, Associnted Business Papers the Assembly Line Indexed in the Industrial Arts Index. ublished every Thursday. Subsacrip- tion Price: United States and Pos- Washington News sessions, Mexico, Cuba, $6.00; Can- $8.50; Foreign, $12.00 year. Single copy, cents. Num- THE NEWS BRIEF Owned and Published CHILTON COMPANY (Incorporated) Editorial and Publication Office Executive Offices Chestnut and 56th Sts., 239 West 39th St., Pa., U.S.A. New York, Y., U.S.A. Weekly Ingot Operating Plant Expansion and Equipment OFFICERS AND DIRECTORS HILDRETH, Vice-President GEORGE GRIFFITHS, Vice-President Just Between Two VAN DEVENTER, Vice-President WILLIAM A, BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY Copyright, 1940, Chilton Company (Inc.) ~ | = | | 4 } Any straight carbon tool steel which can made into die and punch like illustrated and result careful selection raw materials and melting, refining and pouring practice maintained high years punching soft steel .125" thick. unusual appli- cation for straight carbon tool but those who know Pompton expect and get the unusual. Pompton its various carbon tempers can used over wide range applications. It’s good straight carbon tool steel carry regularly your stock. More details about Pompton will found the folder. Send the coupon for it. Please send me: 4 Certified Blue Sheet Pompton New folder entitled Carbon Tool Steel your Production Tool, Stainless, Electrical Steels | | | } | THE IRON AGE ... FEBRUARY 22, ESTABLISHED Vol. 145, No. Monuments Live Ones pyramids Egypt were built the resting places for dead kings. They were projects sort which made plenty work for thousands slaves who received subsistence wages the form food and shelter while these monuments were the making. that respect, they resemble some our present-day WPA projects. They also resemble some them the fact that after completion they had economic value except monuments dead ones. There are other edifices which are monuments live ones. Monuments which create high wages for free men their making and which continue and creating profitable working opportunities for other free men long years after their completion. Dynamic monuments, not static ones. visited one these newly-erected modern monuments last week. was the new home Pratt Whitney West Hartford, Conn. had more men America able and willing erect such great new plants today, our economic troubles would over and there would unemployment this country for any man worthy his American industry. One who visits such plant cannot help but compare the relative values public versus private initiative. Public initiative, with the power commandeer the money from the taxpayers, can build libraries, schools and post offices and other edifices granted social value which will cost the taxpayers still more money after they are completed and long they exist. the contrary such edifices Clayton Burt and his associates have just completed with private capital will create throughout their lives jobs and wages and wealth valuable self-liquidating profitable products from which new wealth and tax money will flow increasing measure. Men who are willing invest their funds these creative enterprises these days hesitancy are doubly entitled known public benefactors. What America needs today more these industrial monuments the live leaders private enterprise. Raw. 3 i a 4 4 ? | 19 i WHATEVER PRODUCT you make, your sheet steel realizes this better than does Inland. serving many industries with hot and cold rolled sheets, Inland called upon develop and supply sheets with special properties better meet such requirements deep drawing, forming, weld- ing, finishing—and scores others. Inland does this matter course—and co-operates with thor- oughness that may surprise you. The chances are good that Inland metallurgists, with their broad experience, have already solved many your problems and that they can aid you materially improving your products reduc- ing your costs. Inland specialist will gladly discuss the matter with you, without obligation. SHEETS STRIP TIN PLATE PLATES STRUCTURALS PILING RAILS TRACK ACCESSORIES REINFORCING BARS e j | | am | uniformity properties the order steel making today. Thus, the problems involved open hearth slag control are pre- eminent. This report goes far simplify and clarify all these problems—and this the first four parts, the authors detail the functioning the basic open hearth, slag formation, transfer iron oxides, and measurement oxidizing power. users steel have been and are now making steadily in- creasing demands upon the steel producers for steels having improved uniform physical properties. This has been brought about largely the de- velopment mass production methods ° PHILBROOK Assistant Superintendent Metallurgy and Inspection and Research Metallurgist Respectively, Wisconsin Steel Works, International Harvester Co. industry, particularly the auto- motive field, which require high degree uniformity material production. There exists also very natural trend toward cheaper mate- rials which give the same properties more expensive products formerly used, such the replacement alloy steels special carbon steels with equal better performance the finished part. These increasing made imperative for the steel pro- ducer maintain closer control chemical analysis ranges the finished product, and develop new methods production and control meet the requirements cleanliness, grain size, hardenability, uniformity, and surface quality. Most these properties have been fixed the time heat steel the molds, and subsequent treatment can remedy mistakes made the open hearth department. There- fore, order govern the properties, has been necessary develop much closer control open hearth practice. Many varieties control the open hearth process have existed for years and are now being improved, and others are still the process development. The composition, physi- cal characteristics and proportion the various components the charge, furnace design, fuel, combustion con- ditions, temperatures, slag composition and properties, furnace additions, fur- nace and ladle deoxidation, teeming conditions, and and con- ditioning all have their effect upon steel quality and cost production, and are controlled the open hearth department. the above items, the slag composition and properties throughout the course the heat and the practice followed are the major factors which influence the quality the steel, well most the properties not determined solely nominal chemical analysis. The subject slag control the THE IRON AGE, February 22, q : i j | ues ° ° 18 H i at } a basic open hearth process will the balance this article. The primary aim slag control regulate the rate reactions and thereby regulate the degree oxida- tion the steel bath. The chemical reactions which take place the fur- nace operate under the laws physics and chemistry—these laws cannot changed any possible variety manipulation, and any practice which attempts buck these laws bound unsuccessful. For example, the operator can, least for transient period, slow down the rate oxygen transfer the bath, but cannot stop reverse the reaction. tion accorded the self-governing characteristics the basic open hearth process, which operates must, under the laws physics and chemistry, slag control very simple. has been thought de- sirable the underlying theory sufficient detail justify the recommendations offered, for the benefit those whom may in- teresting. However, the mathematical parts (set small type and indented may skipped the reader de- Basic Open Hearth Any discussion slag control must take into consideration the slag. basic open hearth process versatile one, can operate charges ranging from nearly 100 per cent scrap nearly 100 per cent pig iron, although com- mon practice the pig iron portion the charge rarely exceeds per cent. the basic amounts over per cent the charge and some sulphur, although elimination the latter difficult and uncertain. processes, This report, however, will limited discussion heats made from pig iron produced from Lake ores, GAS Flame Excess air Waste gas ° ° SLAG the open hearth. METAL There are certain definite factors the reactions which take place the open hearth which can controlled the operator. the other hand, there are changes which can only observe, and while such observation may interest, definitely not control. effort will made this paper distinguish between the limited number factors which can controlled and those changes which can subject only observation. The chemical reactions involved completely interrelated that im- possible deal with changes any one reaction without considering the effects upon all the others. certain amount mathematical and physical-chemical theory neces- sary explain these reactions adequate manner, and because such explanation rather involved the feel- ing exists that slag control must also complicated and mysterious. The authors believe that due considera- 22—THE IRON AGE, February 22, 1940 FeO +Mn mental working the basic open hearth process which places definite limitations the conditions which can arrived the use slag Stripped details furnace design, the open hearth process con- sists melting and refining steel relatively shallow refractory hearth, under flame which directly con- tact with the charge over hearth area, and inclosed walls and roof refractory materials. During the production heat, slag formed which floats the surface the molten metal, constituting rier between the flame and the molten metal. The charge for basic open hearth heat ordinarily consists mixture steel scrap and iron produced blast furnace, either the form pigs molten metal, which latter ordinarily termed metal.” limestone burnt lime also added with the charge assist eliminate consideration high phosphorus slags. The authors are primarily concerned with moderate iron charges which not require flush slag, but the discussion ap- plicable all finishing slags after run- off. The basic open hearth process not simply one remelting steel scrap. The components the charge contain elements which must removed produce steel, such carbon, silicon, phosphorus, and sometimes sulphur. large part the manganese charge also lost, well some the iron. These elements are removed oxidation and, with the exception carbon and sulphur which form gaseous oxides, their oxides combine with the lime charged form the slag. The chief source the oxygen re- quired for oxidation these elements the flame, although some oxygen introduced the form rust the charge, additions iron ore dur- ie 1 1 ( " > ‘ ‘ ‘ = ‘ yt ing the course the heat, and from the carbon dioxide liberated cal- cination the limestone. The flame formed the combustion hydro- carbon fuels, solid, liquid, gaseous, and the products combustion con- tain considerable percentages car bon dioxide and water vapor, usually some excess air. All these gases are strongly oxi- dizing toward the slag and steel the temperature level existing the maintain the temperature level neces- sary for operation with duced with such deficiency air that would neutral reducing toward the bath. Therefore, since the flame all times contact with the bath, may seen that the open hearth process essentially ing process and cannot otherwise. This disadvantage, since the ideal procedure would complete the oxidation the undesirable (and un- fortunately some the desirable) elements, then change over re- ducing conditions and deoxidize the steel completely the furnace, done the electric arc furnace. The best that can achieved along this line slow down the rate oxida- tion slag control, after the major part the refining has been accom plished oxidation, and before any attempt made deoxidize the steel the furnace. Slag Formation The real foundation slag control the charge, because the amounts silicon and phosphorus nated govern the quantity limestone which must added give slag the desired basicity, and likewise govern the slag volume. This state- ment will developed more fully later stage this discussion. The limestone charged directly bottom the furnace over light layer scrap, and the balance the scrap then piled top the stone. The scrap exposed the direct action the flame sweeping over and through it, and oxidation rapid and extensive during the melting down stage. When the pig iron hot metal, the case may be, added, too subject direct contact flame. consequence the oxidizing action the flame, all the silicon the charge and much the carbon and manganese have been oxidized the time the heat melted. The oxides manganese and silicon, together with iron oxides, form light, acid slag which rises the surface the molten metal and affords some protection from the direct oxidizing action the flame. These acid pre- melt slags are composed primarily iron and manganese silicates the type 2FeO.SiO, and but even this stage they contain rela- tively small amounts lime magnesia (MgO), and alumina which are derived from ero- sion the basic banks and bottom the acid slag. When the solid part the charge substantially under cover the Per cent and total iron slag > 2000 Ib. ore added 0.70 per cent carbon from the bath, and that from per cent limestone could eliminate 0.93 per cent carbon. limestone therefore supplies substantial fraction the total oxygen requirement the refining process. the lumps calcined limestone rise the surface and begin into solution the slag, they effect important changes its composition and the reactions between the slag and the steel bath. The dissolving lime, being much stronger base than iron and manganese oxides, replaces 7:00 8:00 3000 Ib. burnt lime added 2—Erratic variations FeO and analyses open hearth slag during the refining period. molten metal and heat has penetrated the hearth, action begins the limestone give the familiar boil.” The CO, liberated the de- composition the limestone active oxidizing agent while rising through the bath, according the may reasonably assumed that this reaction goes practically equilibri- um, which corresponds about per cent completion under condi- tions prevailing during the lime boil. this case, 1000 Ib. limestone (98 per cent will form about sidered from different angle, the CO, derived from per cent lime- stone charge able remove these oxides from their silicates with the formation compounds such CaO.FeO.SiO, and Later, more lime goes into solu- tion, this replacement completed with formation dicalcium silicate (2CaO.SiO,). still more lime dis- solved, calcium ferrites and and tricalcium The phosphorus the charge oxidized and combines with the lime the slag form tricalcium phos- phate Part any fluorspar added the with the latter form compounds, together with free lime, FeO, and MnO, exist fluid phase THE IRON AGE, February 22, 1940—23 2:00 3:00 4:00 5:00 6:00 Time the slag, least near the end heat. The refractory bottom, which con- sists primarily magnesite, eroded the bath and slag, and the MgO liberated partly dissolved the slag, but large part such magnesia persists throughout the heat periclase, which mineral form MgO. Since this periclase may hold per cent its own weight Fe,O,, may introduce errors the chemi- cal analysis slags for active con- stituents with regard both MgO and Other oxides, such titania and chromic oxide exist the slag compounds little importance slag control. example, spinel type minerals such and are frequently identified slags. Although the above picture slag formation appears rather involved, the salient feature that the early slag acid, and lime dissolved re- places the weaker bases, FeO and MnO, with the formation calcium silicates and more basic slag. Transfer Oxides When enough lime has gone into solution release FeO from its stable compounds silicates, the liberated iron oxides are then free enter into other reactions and become the car- rier oxygen from the flame, through the slag, the steel bath. The mechanism this reaction was sug- oxide solution the slag oxi- dized the upper surface the slag, which the slag-gas interface, carried, primarily convection, the lower surface the slag, which the slag-metal interface, and here reacts with the bath, giving oxygen form more FeO, part which dissolves the steel. The FeO dissolved the steel re- acts with and oxidizes silicon, carbon, manganese and phosphorus, 1C. Herty, Jr., Christopher, Freeman, and Sanderson, “The Physical Chemistry Steel-Making. The Control Iron Oxide the Basic Open- Hearth Process.” Cooperative Bulletin (1934), Mining and Metallurgical Ad- visory Board, Carnegie Institute Tech- nology, Pittsburgh. Uber das Verhalten des Mangans bei der Stahlerzeugung,” Stahl 52, 133-44 (1932). 3H. Vacher, discussion refer- ence (5). Chipman, “Effect Slag Com- position upon Oxygen, Carbon and Sul- phur the Bath,” 1937 Open Hearth Proceedings, 110-114, American Institute Mining and Metallurgical Engineers. 24—THE IRON AGE, February 22, 1940 thus reduced again. The FeO the slag formed reduction the turns the upper surface the slag This process oxygen trans- fer from the flame the bath may therefore visualized consisting two cycles, one the slag and one the bath, shown Fig. From evident that the rate oxygen trans- fer the bath, which determines the rate elimination metalloids, dependent upon the concentration the slag the oxygen carriers, name- ly, the iron oxides, and the ease with which these oxygen carriers can mi- grate between the upper and lower surfaces the slag. This ease migration largely matter slag viscosity and degree agitation. The more action the bath and slag, the greater will the convection, and addition the interface, which the re- actions take place, greatly increased area the disturbances caused the increased volumes gases liber- ated from the bath. Since slag control aimed governing the rate oxidation the bath, therefore concerned primarily with regulating the content iron oxides and the con- sistency viscosity the slag. The introduction FeO the steel bath from the slag simple process FeO liquid iron 3000 deg. 1.7 per cent. This far above the amounts FeO encountered open hearth practice, and therefore the abil- ity the steel dissolve FeO not limited this factor. The distribution FeO between the slag and the steel bath subject the physical law governing the dis- tribution solute between two im- miscible solvents. Therefore, equi- librium conditions are assumed, which conditions practice not exist but can only approached, the ratio FeO the slag FeO the steel bath is a constant at any given temperature, ( FeO Herty found that the value this constant decreases with increasing tem- perature, which means that the solu- bility FeO the steel bath increases more rapidly than its solubility the slag the temperature raised. The activity the iron oxide the bath proportional the weight per cent FeO*. One the difficulties mak- ing practical use the above expres- sion, however, the lack exact knowledge the activity the iron oxides the open hearth slags. Measurement Oxidizing Power Several methods deriving mea- sure the activity the iron oxides the slag from the chemical analysis have been common use. Per cent FeO, total oxygen from iron oxides, expressed (FeO 1.35 the same figure corrected for basicity, the total FeO and “total iron” the slag have all been used. The disadvantage using expres- sions involving FeO and the practical impossibility obtaining sample slag for chemical analysis which has the same proportion these oxides the slag the furnace. The slag the furnace varies widely from top bottom proportion FeO due the previously mentioned “carrier the iron oxides, and therefore the results ob- tained depend upon the position the slag layer from which the sample taken’. The proportion the two oxides also dependent upon cooling conditions, because oxidation FeO air. This illustrated Table the sets analyses samples poured from the same spoon- ful slag such way that one had normal access air during cooling, while the other was protected from the air until black. could, course, have gerated pouring the air” sample very thin layer. combination both these ef- fects illustrated Fig. the data for which were obtained from low carbon heat. may noted that there are erratic breaks the FeO and curves, with rise these swings could not correlated any way with conditions the fur- nace the manner working the heat. illustrated also Fig. the percentage total iron the slag not affected any the con- ditions mentioned and has been found from experience offer better cor- relation the study furnace re- actions. true figure for the measure the activity slag would based upon mol per cent, and since present knowledge the mode combination the molten slag the separate oxides determined chemical analysis does not warrant the calculation mol fractions, pointless use elaborate expression for oxidizing power. empirical measure the oxidizing power basic open hearth slag, the total iron content ap- pears the best available the present state knowledge. The total iron content the slag does not itself give complete pic- ture the oxidizing power slag. the basicity slag increases be- yond certain point, the increased total iron does not represent propor- tional increase oxidizing power the slag. and have both shown that basicity the slag increases, the ratio iron oxide We j the slag oxygen the steel does linearly with rising basicity. The methods expressing basicity and iron oxide content the slag fer, but both cases the curves show the increase this ratio begin when the lime content the slag ceeds slightly the amount necessary form dicalcium silicate and tricalcium phosphate.* decrease the tivity iron oxides the slag with increasing basicity probably due the formation stable calcium fer rites, postulated Herty, since bound this manner would inactive and longer able enter into the cycle oxygen transfer from the flame the bath. possible develop experimen- tally the relationship between basicity the slag and activity, oxidizing power, the iron oxides over the usual range conditions for given shop. Several methods deriving expression basicity from the chem- ical analysis have been used for theo- retical work, but the only measure basicity which useful for practical furnace control the ratio lime silica the slag, because this can curve shows definite break whether the line for variation dis- tribution constant with basicitv may extrapolated below a base:acid ratio of 1, or whether the FeO ratio becomes con- stant below this point in accordance with the distribution law. TABLE Analyses Showing Effect Oxidation Air During Cooling Slag Samples Experiment Method Cooling Cooled air Protected from air Cooled air Protected from air Cooled air Protected from air Cooled air Protected from air Cooled air Protected from air 9.8 10.6 1.8 17.2 6.3 17.8 17.9 5.6 17.9 8.6 8.8 9.6 2.0 8.9 11.8 12.5 2.6 11.5 12.9 13.1 14.0 3.3 13.2 estimated rapidly and fairly from visual inspection slag “pan- seems unnecessary, however, derive formal relationship this sort, because the basicity the slag itself controlled within practicable limits, the oxidizing powers slags with the same iron content will equal. Since the aim slag control reproduce conditions which have been found repeated observation best for particular period the heat. satisfactory for control purposes know that slags controlled basic- ity and given iron content will always have the same oxidizing power, even though this may not strictly pro- portional the actual iron analysis. the production quality killed steels. the range basicity desirable during the refining stages heat low enough that ferrite formation not all extensive. might re- marked, however, that the produc- tion rimmed steels, increasing the iron content the slag “control” through the use large amounts lime some extent misleading, cause much the iron oxides thus introduced into the slag are inactive toward the bath, although this not intended deny the necessity in- creased basicity rimming steel slags. Ed. the second section this report next week, the authors will describe the elimination carbon from the bath, departure from rate oxidation slag and bath, with proper calculations each instance, and the effect temperature. Three Compositions Sinterloy Steel NEW powder which pressed into any desired form the accepted methods used powder metallurgy being distributed Charles Hardy, 415 Lexington Avenue, New York. The powder designated Sinterloy available three compositions for the production steel carbon content approxi- mately 0.15, 0.4 and 0.8 per cent. said that the material most cases may pressed directly into the shape the finished product that machining cost and metal losses are entirely eliminated. frequently used particular applications where difficult machine work required and exact duplications parts desired. Excellent results are also claimed for applications where wear resistance important factor. The Sinterloy powder said suitable for products such gears, cams, pump rotors, washers, pins, and rivets, and being used for splines operating high speed under alternat- ing stresses where endurance fa- tigue importance. stated that the powder dense and homogeneous and exhibits neg- ligible change shape sintering, and also that may hardened heat treatment the accepted hard- ness usually experienced with steels also may pack-hardened the same ordinary steels. The Sinterloy powder stocked the following compositions Sinterloy 0.15 Sinterloy 0.40 Sinterloy 0.80 These compositions fully determined amounts mium. toughness particularly de- sirable nickel may added the amount 1.5 3.0 per cent. The powder should pressed tons per sq. in., and sintering should take place controlled atmosphere prevent oxidation and decarburization. deg. 1150 deg. the ordinary furnace hr. high frequency induction furnace. The grade can heat treated (Brinell 485). Tensile strengths 80,000 120,000 Ib. per sq. in. have been obtained. Under the microscope the usual steel constituents observed. THE IRON AGE, February 22, 1940—25 1e IS y > l i at } many years the foundry in- dustry has been producing what may considered fairly good castings. foundryman has right feel proud his handicraft when one considers what expected with simple sand and metal, say nothing being required meet specific chemical, physical and appear- ance requirements. The improvements that have taken place the production castings from year year may well credited the inclination progressive foun- drymen take advantage the data compiled foundry technicians and scientists. will not necessary list here the many requirements casting buyers today most foundry- men are familiar with de- sirable, however, stress the impor- tance played gating producing modern castings. Jobbing Shop Practice Gating and heading shop present many problems, due the fact that changes design al- low proper feeding are impossible, the foundry seldom consulted before the casting designed and patterns are made. This makes difficult produce sound casting without plac- ing considerable burden the foun- dry, even additional expense the before satisfactory casting made. IRON AGE, February 22, 1940 ANTON JOHNSON Works Manager, Oklahoma Steel Castings Co., Tulsa, Okla. ° metal, the law gravity and rate solidification all enter into the making sound steel casting. Much can said favor mold manipulation pouring and centrifugal pouring, but these methods can only applied when design permits and they require extreme care and special rigging. Therefore, the following data will deal only with the orthodox man- ner pouring, that is, the mold when ATING this flanged ring the joints and into the heads arrangement the re- sult being cold metal the bottom the mold hot metal the heads where was needed. Pouring head ° poured being the same plane when molded. There are various kinds and ways gating, and they all have their ad- vantages—bottom fountain, horn, side gate, gating joint, step gates, top pouring through head. These types are used single multiple, according size, shape and metal section the castings involved. aim selecting particular gate 4 Pouring head Gate Gate was imperative producing this clutch that the flange metal solid avoid losses machining the groove. assure the flange metal being solid, the casting was gated into the head, with pad leading from the head directly the flange. The gate was cut angle avoid cutting cores. Gating from the bottom would have created numerous hot spots and shrinkage defects. equalize shrinkage much possible and avoid very important part gating the proper making gates, both down and ingates. The old, still too often used, practice for the molder use any stick pipe that close hand, practice inadvisable for sev- eral reasons. too small, the casting may misrun; too Gate large, metal wasted, and too large gate may even bleed the casting the gate. Second, these sticks pipes are very often rough dented and may result tearing apart the sand grains these battered pieces are withdrawn from the mold, leaving broken in- stead smooth sand surface. This makes very easy for the rushing metal cut into the disturbed sand grains, washing them into the mold and eventually trapping sand casting. Another cause washed-in sand improperly rammed gates. common sight rough, knot- tv, irregular gates, due soft ram- ming and careless cutting the mold- part. Carelessness ignorance gates still another cause for cutting washing both mold and cores. Whenever possible, the gate should placed not let the metal HIS screw-type valve called for joint and head gating. Pads under the heads help feed the heavy body section. strike hard against mold core. This can done placing the gate paral- lel angle the mold core sur Tile Core Gates Recommended tices, the writer recommends the use RIDGE head feeding both top and side flanges this valve made possible consistently produce good castings. Note use padding under the top flange feed heavy body section. tile core gates. light and medium sized work core gate satisfactory. The well-known saving that chain stronger than its weakest link” can changed casting cleaner than its Improper placing the gate often causes hot spots casting that can- not fed, resulting shrink cavities found the customer, some- times only after considerable expense. has direct relation gating. The gate permits the metal enter the mold, and the function the head pack the metal in, feed the casting. Feed Heads Important The part the casting which the metal enters will stay the hottest, provided the metal sections form. they are not uniform, shrink- age and cavity problems are increased. is, therefore, important determine which part parts will affected the temperature metal the blemish the groove this cable sheave detrimental long cable life and particular care gating and feeding was necessary eliminate the possibilities defects this point. bottom gate into the hub, with heads the intersections groove and web, was used successfully avoiding groove defects. Pad under the center head serves feed dan- gerous hot spot. gate well the heavy sections and intersections, where hot spots are likely occur. These are the places where feed heads should placed and the gate should kept close one these possible order that the head can feed minimize hot THE IRON AGE, February 22, Gate Pad Pad 5 and head gating was success- fully used casting this blank sprocket. Pads allow head feed vital tooth sections. spots. What meant natural hot spot one caused heavy sections intersections. The artificial hot spot the one caused the gate. It, there- fore, necessary have some in- stances many heads there are hot spots, regardless whether nat- urally artificially created. The most common position place heads the uppermost part the casting, but often necessary place them sides even the bot- tom, especially cases heavy metal sections that cannot fed due the lighter metal sections above, due having the gate into bottom and thus causing hot spot. order feed some non-uniform metal sections, often necessary resort The class work made Okla- homa Steel Castings largely oil country castings vari- ous shapes and weights and must meet the most exacting requirements. Each casting presents different gating and heading problem. few these jobs HIS cable drum was into light flange and away from chined metal inserts avoid hot spots and simplify heading. are illustrated herewith. Excellent re- sults were obtained using the gat- ing and heading methods The author wishes express his appreciation William Kunz and Hugh Coshow for their assistance preparing this report. PRE-FINISHED CLAD ALUMINUM the market for the first time, and considerable interest various branches industry are two new pre-finished bonded metals which combine the attraction and dura- bility nickel and chromium with the lightness, strength and workability aluminum. These two plated metals are nickel-aluminum and chromium- aluminum, recently introduced the manufacturer, Co., Peru, These two metals are formed surface chromium nickel bonded num base metal, using the Krome Alume process patent No. 1,971,761. the result exhaustive tests conducted over period four years, the American Nickeloid that the process produces coatings that can fabricated with positive assur- ance that they will not peel. One interesting test adhesion made soldering two nickel-aluminum together, then pulling twisting the joints. claimed that every case the solder ruptures and with indication peeling the nickel coating. Because the aluminum the luster the plated surface not dulled. This, addition adhesion, has been the fault with sev- eral previous attempts plate alumi- num other methods. Although these two new composite articles are made composite metals, either nickel-aluminum chro- mium-aluminum. 28—THE IRON AGE, February 22, 1940 metals have just been introduced, stated that number manufacturers have cooperated during developmental work. One manufacturer has adopted chromium-aluminum for the top cover glass coffee bottle. prominent stove manufacturer has used the metal for fume vents gas stoves and sev- eral manufacturers etched name- plates are using the material. Although the American Nickeloid Co. not equipped plate formed parts after fabrication, the process has been used for this purpose the com- mercial production tea kettles fabri- cated from sheet aluminum fin ished chromium. stated that these kettles have been use for three years with indication any peel- ing. The two new finished metals are available sheets sizes and gages from in. 0.064 in. choice bright satin finish crimped, cor- rugated patterns adapts the metals many uses and designs. The manufacturer reports that both metals are easily workable during the manufacturing process, and are highly resistant corrosion, rust, tarnish. also claimed that they can bent, stamped moderately drawn without damage the permanently bonded coatings. Gate Gate Head Head. q a Engineer, Pratt Whitney, Division Niles-Bement-Pond Co., West Hartford, Conn. hardened alloy steel gears, and the role grinding assur- ing the high accuracy tooth contour necessary for maximum strength and operating quietness are here outlined. Gear tooth grinders generating and form-wheel types are illustrated and data are given the preparation gears for tooth grinding. The second part, appear early issue, devoted methods mounting the work, and the grinding wheels and types coolant employed. These articles are from paper presented Mr. Dixon the recent 22nd semi-annual meeting the American Gear Manufacturers Association. RESENT-DAY requirements aircraft, automotive and ma- chine tool industries for gears extreme accuracy and long life, capable smoothly transmitting in- creased horsepower, have necessitated the use hardened steel gears with ground tooth profiles. removing inaccuracies cutting and distortion due heat treatment. believe that the elimination errors can best accomplished grinding the gear tooth profile. The accuracy Use hardened steel gears with their increased physical properties has permitted the designer use gears narrow face and fine pitch, and lighter construction. This has resulted gear trains capable transmitting much greater power without increasing the size the gear box necessary house them. easy imagine how much wheel gear tooth grinder for spur gears eter. These machines have reciprocating grinding wheelhead and table actuated master rack and larger our modern machines would soft steel cast iron gears were still used, and how much more floor space would required accommo- date them. The aircraft engine with quirements minimum weight per horsepower use gear. gears extremely light construction and order use such gears, hard- ened alloy steels had used get the necessary physical properties. While hardened steels take care the physical properties required, this itself not sufficient. neces- sary uniformly distribute the load the gear teeth, and this requires tooth spacing and profile produced grinding makes for smoother tion, produces gears which are much quieter running, and also permits use high tooth speeds which could not considered with gear teeth. Since the Lewis paper strength gear teeth, which included gear tooth forms factor the strength formula, was prepared 1892, much has been written the subject. The committee the strength gear teeth went far develop test machine, and its reports were Whitney machines, also re- ciprocating wheelhead type, ‘or helical gears in. diam- eter. included findings the effect tooth form and spacing accuracy shown conclusively that accuracy has marked effect the load carrying ability gear teeth, and errors little few ten thousandths differ- ence from one another result load carrying losses that are enormous. The effect accuracy gear teeth noise has also been given intensive study, and writings the subject have appeared various trade and 3—Deutsch Niles machine, another generating-type, re- ciprocating wheelhead gear er. ABOVE 4—In the Lees- Bradner gear grinder the workslide actuated master rack and gear for generating and index. technical papers. the Feb. 1938, issue Steel, for example, Bjornberg, consulting nois Tool Works, Chicago, pointed out that accuracy gear teeth the real answer quietness. Mr. Bjornberg further stated that interesting note that when pair gears are ground accurately, they quietly under actual operating condi- tions than any other class gear, and when noise does occur the trouble can generally traced the design the gear bearings and housing. find that longer necessary spend the time required accurate- cut hob the gears. The finish cut can eliminated. longer necessary use non- treatment eliminate distortion. Trouble the test stand cally eliminated. Expensive disassem- bly and reassembly the gear box with its consequent delays not ex- The savings enumerated the above three paragraphs cover general- the cost gear tooth grinding. matter fact are told lead- ing machine tool manufacturers that their present ground-tooth gears cost less than their previously unground- tooth gears. While the chief users gears with ground teeth are aircraft, automotive, machine tool, diesel engine, bine manufacturers, such gears are also being used tractors and marine engines, | | | 4 | >» The increased use ground tooth profiles has brought the devel- opment gear grinding machines and equipment their present state high Two different types tooth grind ing machines are now being manutac- tured. These are the generating type and the form wheel type. the gen- erating type different methods are used produce the tooth profile. The methods used some the gear tooth grinder manufacturers The Pratt Whitney single-wheel reciprocating diameter, wheel head and grinding holding table actuated master rack and gear, which take care generating the involute and the index (Figs. and 2.) The Pratt Whitney single-wheel gear grinder for gears in. diameter has reciprocating grinding wheel head, and workslide actuated gearing for generating the involute, and index for tooth spacing. The Deutsch Niles machine has reciprocating grinding wheel head and workbase actuated gear- ing for generating the involute and in- device for spacing. The Lees-Bradner machine (Figs. RIGHT Rear view Lees- Bradner gear grinder showing wheelslides. RIGHT 7—Close-up Pratt Whitney two-wheel machine operation the teeth helical gear. LEFT IG. 6—Two-wheel Pratt Whitney gear grinder, also non reciprocat- ing wheelhead type. grinding wheel head and workslide actuated master rack and gear for generating and index. The Pratt Whitney two-wheel machine (Figs. and has non- reciprocating grinding wheel head and workslide actuated master rack and gear for generating and index. The Maag machine has non-re- ciprocating grinding wheel head with feeding workslide actuated gear- ing and uses pitch drum generate : d « the involute and index plate for spacing. (Fig. 8.) the form-wheel type machines, such the Detroit (Fig. and the Orcutt Birmingham (Fig. 10) tru- ing device for forming the wheel and index plate are used. The sequence operations for the ground-tooth gear should arranged provide proper surfaces for locat- ing and holding the gear during the tooth grinding. Gears mounted arbors should have the bore ground uni- form size, and the locating surfaces must correct relation with the bore. gears that are bushed, such ABOVE 8—In the Maag gear grinder pitch drum gen- erates the involute and index plate used for spacing. LEFT 24-in. diameter gear grinder, form- wheel type unit built the Gear Grinding Machine Co. BELOW 10—Orcutt Birmingham gear tooth grinder, another form-wheel type machine. idler gears, the bushing should place and properly bored. Gears having external mounting re- quirements should uniformly ground their bearing diameters. Gears which are ground mounting them centers must provided with centers adequate bearing support dimensions. The hob cutter should such dimensions leave 0.005-0.007 in. stock removed grinding from each side the tooth. This should sufficient take care heat treat distortion and cutting irregularities larger diameter additional stock should allowed. Unless imperative grind the tooth the root, the hob cutter should sufficient addendum length leave wheel clearance that point. (To CONCLUDED) 32—THE IRON AGE, February 22, 1940 oe q ELECTRIC OVEN AIDS BICYCLE many years the Cleveland Welding Co. had assemblies consisting primarily automobile wheels, rims, truck wheels and similar articles. With the return the popularity the bicycle the company realized that its plant was ideally equipped for the manufacture completed bicycles, and for the manufacture steel chairs—a market that developed about the same time. the manufacture the other as- semblies the company had experienced with the various types enamels and had been using electric batch ovens for baking this finish. Upon investigating the possibilities bicycle production the company realized that would have use the continuous oven, and also that would have considerable experi- mental work the lacquers, temperatures, times produce finish with lots “sales appeal.” Uniform appear- ance colors was also important requirement the bicycles would displayed groups and the red black bicycles turned out today must match the reds blacks produced weeks months before. After determining the production desired, suitable type oven was tenta- tively heat was decided upon because the consist- ently uniform production and appear- ance obtainable. Finally chamber continuous type, heat- seal unit, one the most efficient constructions for continuous oven, was secured from another Cleveland plant which had discontinued line automotive head lamps. This oven, originally built the Young Broth- ers Co., Detroit, was revamped and set the same company for the handling the bicycle frames and parts. The oven installed the plant the Cleveland Welding Co. shown the accompanying illustration. The work loaded the overhead mono- rail conveyor and carried the mouth the oven. then starts its travel through inclined preheat, emerging from the preheat the top ODUCTION the incline into the firing chamber proper. then passes through the firing chamber predetermined rate speed giving the required time baking, and then allowed rela- tively slow cool passing down the incline the opposite end the oven. This preheat slow cool eliminate the thermal shocks frequently experienced lacquered work, and give much better finish. The monorail which traverses the furnace also extends around as- sembly area outside the furnace, elimi- nating handling and allowing the work loaded and unloaded the vari- ous assembly points. The double chamber the oven actually gives the advantages two which means that different speeds and different temperatures can run each part the oven, thus eliminating the necessity for storing the parts while the oven baking the lacquer the part that requires the longer shorter time, the higher lower heat. ovens, The oven heated with General Electric oven-type heaters having connected load 250 kw. equally di- vided between the two sections the OUBLE-CHAMBER, continuous type electric oven used the Cleveland Welding Co., Cleveland, for baking the lacquered finish frames and other parts bicycles. The work carried through preheat into the firing chamber the top, and cooled passing down the incline the opposite end the furnace. Photo courtesy General Electric Co. DRISCOLL Cleveland Electric Illuminating Cleveland oven, and each half the oven the heat divided into two separate control zones, thus assuring uniform- ity temperature throughout the length travel. These temperature- control instruments are set for the de- sired temperature and automatically control the power input each zone the heating chamber accordance with the requirements that zone. After the work has been unloaded from the monorail any necessary strip- ing done hand and the parts are hung back the conveyor hooks, where they are thoroughly dried their way the assembly department. assure work maximum ty, the area surrounding the oven, which comprises the dipping, drain- ing, striping and some assembly work, illuminated high intensity light- ing without glare shadows. This installation shows the many possibilities small heating units applied major production jobs. distributing many small heaters the furnace, very satisfactory temperature distribution obtained. addition producing excellent work, this electric oven has proved economical opera- tion. ay BELOW Flex-Seal new kind stainless steel cooker made Vischer Products Co., Chi- cago, using Armco steel. so-called bottom permits the use high heat with- out danger hot-spotting, when little water used. patented flexible stainless steel lid locked place steam pressure— the cooker cannot opened until all the pres- sure released. HIS new furnace for melting zinc was re- cently perfected the technical staff the Glenn Martin Co., Bal- timore airplane manufac- turer. The new unit, which said eliminate both the heat concentration and erosion metal pots typical older type fur- naces, has been steady use for more than year with signs deteriora- tion. inner pot sus- molten lead other metal metallic alloy, having lower melting point than the zinc, which transfers heat the pot containing the zinc. The photo shows the inner pot container being removed for exami- nation. cas 7 RIGHT HIS tiny Atom engine makes use three Mazlo magnesium die castings bring its weight down scant oz. The engine de- velops hp. and will operate model airplane. Mag- nesium, weighing one-fourth much steel, used for the crank- case, crankcase cover, and spark advance lever. BOUT 100 tons copper smelted daily this small blast furnace, which was recently built for shipment Africa the mining division Allis- Chalmers Mfg. Co., Milwaukee. The cop- per produced later refined converter. For many years this country, copper has been re- duced reverbera- tory brick kiln type furnaces, often quite large. THE IRON AGE, February 22, ITH the greatest membership its history—well over 10,000 exclusive over 3700 student varied technical program, last week’s 152nd annual meeting the Amer- ican Institute Mining and Metal- lurgical Engineers New York drew record attendance 2800 metallur- gists and engineers. The Monday afternoon All-Institute meeting heard Merlin Aylesworth, former president National Broad- casting Co., and Lt. Col. Codd, executive secretary, Army Ordinance Association, Washington, discuss sub- jects vital importance American industry and defense. Mr. Aylesworth spoke “The Future American Industry,” and Col. “Industry and Defense.” New officers the also were introduced the All-Institute meeting. Frank Sisco, editor the Alloys Iron Research the Engineering Foundation, New York, was elected chairman the Iron and Division for 1940; and Edmund Wise, staff advisor the research laboratories, International Nickel Co., Inc., was elected chairman the In- stitute Metals Division for 1940. Wednesday afternoon Edgar Hutton Dix, Jr., chief metallurgist, Aluminum Co. America