The Iron Age 1926-07-15: Vol 118 Iss 3

71 qze 91 At Notice—You will find a convenient summary of the week’s news on the orange-bordered editorial page. ca ane. NEW YORK, N. Y., JULY 15, 1926 Single Copy, 25 Cents peliehed — seatnll on skeen aie » 18 187D. ot Bent Six Dollars a Year in U. S. Vol. 118, No. « at New York un ‘ Canada $8.50; Foreign $12 l-cls Se mat te J THE IRON AGE | ) HEN the inevitable increased demand for V gas comes, the operator of Becker Type Combination Ovens is in a favored position, for the assurance of a future supply of over 60% more coke oven gas is built into the Becker Oven. By substituting blast furnace gas or producer gas as oven fuel, this potential capacity becomes actual production. The Iron and Steel Companies buy this insur- ance in their coke plants for it is one of the most fundamental properties of the Becker Oven. It is the more valuable because no company can say when and to what extent it will need more gas. The Koppers Company Pittsburgh, Penna. Chicago, IIl. New York City July 15, 1996 Built-In Insurance Against Greater Gas Demand 1926 THE IRON AGE New York, July 15, 1926 ESTABLISHED 1855 VOL. 118, No. 3 Foundry Skip Hoist Saves Six Men Adaptation of Blast Furnace Design—Labor Cost Cut in Half Daily Melt In- creased — Safe- ty Made a Pri- mary Consid- eration Lower End of Skip Hoist Used for Charging the Cupola. The charging cars are pushed onto the skip platform and locked into place ECHANICAL charging of a foundry cupola, M with an application of the skip hoist in the design of the charging equipment, has resulted in a marked saving in labor at the Detroit foundry of the Griffin Wheel Co. For years the skip hoist has been used for elevating materials for charging blast furnaces, but its use in foundries has been limited to placing coke in storage. Its adaptation to cupola charging is new in foundry practice and has proved successful at the Griffin foundry. The cupola charging equipment in the Griffin foun- dry is a modification of the skip hoist in that the skip bucket has been replaced by a platform similar to a freight or passenger elevator. The charging cars are pushed onto this platform and loeked in place. The skip is then started and the platform with the car is hoisted up to the cupola, where it is tilted and the load discharged. The skip platform with its empty car is then lowered to the yard level, where it comes to a stop, and the empty car is replaced by a full one. The operation is then repeated. Outside in the yard parallel tracks are used to shift the cars to and from the various storage points and a transfer is used to place the car in front of the skip platform. Ease in handling cars and flexibility of the system are the outstanding features. Dumping Produced by Guide Rails The skip platform, approximately 7 ft. wide and 8 ft. 6 in. long, is equipped with four flanged rollers mounted on two through axles. These rollers are guided by the rails to the top of the skip, where the guides are curved to produce the dumping action. The skip structure, approximately 10 ft. wide, and inclined at an angle of about 67 deg. from the horizontal, is built of structural steel well braced. Two hoisting ropes are used, one on each side of the skip platform. These pass over deflecting sheaves at the top and from there down to the drum of the hoisting equipment. An equalizer is placed at the top of the equipment to insure an equal pull on the two ropes at all times. The dumping guides are so ar- ranged that the car is emptied of its load almost in the center of the cupola. Hoisting is effected by a 40-hp. slip-ring type mo- tor driving a drum 30 in. in diameter, geared down to the proper speed through heavy cast steel gears. The motor, gears,drum and a limit switch are all mount- ed on a rigid structural steel base. The limit switch permits automatic operation. After the controller is turned on the skip is hoisted, dumped and returned to the yard level automatically. A drum type controller is provided, which gives the operator better control during the dumping operation and thus permits him to spread the charge in the cupola. The height of the hoist or the travel is approxi- mately. 46 ft. The platform is hoisted at a maximum speed of 75 ft. per min. At this rate a round trip can be made in a little over 1% min. The control per- mits the platform to be stopped at the charging floor 139 140 level, so that loaded cars can be placed in storage on this floor. These cars can afterward be placed on the skip platform and emptied into the cupola in the usual manner. Safety switches are provided at the top and bottom of the hoist, to act in event of the failure of the limit switch, and a solenoid brake on the hoisting engine will hold the load when the power is off. ‘ Dumping the Ri a Charge Into the Cupola. A drum -type hand _ control- ler enables the operator to spread the charge in the cupola THE IRON AGE July 15, 1926 The Skip Plat- form Can Be Stoppedat the Charging Floor Level So That Load- ed Cars Can Be Placed in Storage on This Floor, if Desired Save Six Men of the Eleven Needed Before Five men are used for the entire charging operation. One man makes up coke charges and two are employed in the yard, loading and shifting cars, and in moving cars to and from the hoist platform. A crane man devotes about 60 per cent of his time to handling ma- July 15, 1926 terial for the cupola. One man is stationed at the charging floor to control the dumping and to operate the skip hoist. When the cupola was hand charged, eleven men were necessary for the work; consequently, with the hoist, there is a saving of six men. Not only has the skip hoist resulted in a saving of labor but, with the fewer men, the daily melt has been increased. Formerly 105 to 110 tons, it has been raised to 140 to 160 tons. The skip hoist charging equipment has had no detrimental effect on the operation of the cupola and coke consumption has been low. Chemical analysis of the iron has been satisfactory. Various subjects in connection with the cupola, such as separating and supporting the stack independent of the body of the cupola, the lining, height of the charges, etc., had to be taken into consideration when it was decided to use the skip hoist type of charging 7K ” a ; yt fay P* THE IRON AGE 141 yearly through corrosion, states the report, which asks why electricity cannot be used to help,“in producing at reasonable cost iron which will rust less rapidly or not at all.” Large deposits of iron ore, which on account of their distance from fuels are of no commercial value, will be immensely important when iron can be produced di- rectly from its ores by means of electricity, it is added. Much progress has been made in the production of electrolytic iron, the report points out, adding: “About fifty years ago iron was produced elec- trolytically by Elihu Thompson and Edwin Rice, but found so hard, rough and brittle that nothing was done with it. Since then many patents have been issued in France, the United States and other countries. A few years ago the most successful concerns in France and the United States found that each had knowledge and Be Cupola Charging Cars Are Loaded on Parallel Tracks in the Storage Yard and Are Shifted on a Trans- fer Track to the Front of the Skip Platform. Lower end of skip hoist appears in the large open door at center equipment, but these problems were all worked out satisfactorily. This skip hoist was a combination of several pre- vious forms of mechanical charging used by the Griffin Wheel Co., which were adopted because of the scarcity of labor during the war period. The equipment, first operated on Feb. 9, 1925, has been in continuous oper- ation ever since and has contributed toward making this foundry one of the most economical producers of car wheels. The engineers of the Griffin Wheel Co. originated the plan to use the skip hoist type of me- chanical charging equipment, and it was built by the C. O. Bartlett & Snow Co., Cleveland. Reclamation of Iron by Electrolysis Recovery of iron from rubbish is the aim of metal- lurgy, Charles P. Perin, New York mining engineer and head of Perin & Marshall, consulting engineers, says in a research report to the Engineering Foundation. Reclamation by electricity, he asserts, is possible. “Discarded iron objects, from cans to automobile bodies, are increasingly disfiguring the countryside, especially in proximity to communities,” declares the report. “Large tanks of iron solvent, ferrous chloride, for example, could be maintained in convenient places into which these wastes could be dumped. Then the iron could be recovered by electrolysis.” Twenty million tons of iron and steel are destroyed patents that would be valuable to the other. They combined forces. At Niagara Falls electrolytic iron of a purity of 99.96 per cent is being produced, while research and development are going on. This iron is resistant to corrosion and has advantageous physical qualities.” Indirect Heat Oven Patent Again Held Valid A decision has been rendered by the United States District Court of Minnesota, Fourth Division, sustain- ing patent No. 1,104,652 owned by the Gehnrich Indi- rect Heat Oven Co., Inc., Long Island City, N. Y., in an action for infringement brought by the Gehnrich Co. This is the second time that the patent has been held valid. That part of the patent that was infringed is covered in claim No. 1, which reads as follows: “In a portable oven, the combination with a casing adapted to constitute the upper, lower and side walls of a bake compartment; a heat compartment arranged within the upper part of the bake compartment; a fire compartment arranged within the lower part of the bake compartment; a series of flues situated in the bake compartment separated from.the walls and ex- tending from the fire to the heat compartment; devices for heating the fire compartment and a chimney lead- ing from the upper compartment.” Rimmed Steel and How It Is Made II.—Melting Furnace Practice—Effect of Manganese—Inter- mediate and Central Holes BY HENRY D. HIBBARD [The first article of this series was published in THE IRON AGE, June 24. It described this type of steel and discussed its uses and properties.] NTERMEDIATE holes are normal in rimming steel and, when it is well made, lie quite uniformly in a narrow zone 2 or 3 in. in from the surface. They are thought to be formed by the last carbonic oxide to separate from the steel, the bubbles being entrapped in the mushy metal next to and adjoining the shell already frozen. The larger ones are of irregular shapes, the smaller approximating to spheres about % to % in. in diameter. The size and location of these holes is in some meas- ure a function of the carbon concentration for, when that is at a minimum, as in Armco iron, containing about 0.02 per cent, the intermediate holes are rela- tively small and few in number as compared with those in steel containing a notable amount of carbon, say, about 0.10 per cent or more, and they are sometimes located between 3 and 4 in. from the surface. Central Holes A few of the central holes are generally present in well-made rimming steel, located at random in the central portions of the ingot. They are thought to be formed by bubbles of nitrogen or ammonia (NH,), one or both, because a freshly split ingot sometimes smells of ammonia, as does the gas from a central pipe cavity. Sometimes, and perhaps always, an ingot, which has skinholes all over like honeycomb, has a solid interior with no central holes. In such an ingot the central metal is more coarsely crystallized than in one having no skinholes, but its quality is unknown, as such ingots are always remelted. It is quite likely that the central- hole gas is eliminated in part with the skinhole gas by the boiling action. Melting Furnace Practice Running the furnace and its care, the melting stock used, charging the furnace, melting down, decarburiza- tion and sampling are not peculiar to rimming steel except as to manganese in the charge as noted later, and ‘to the effect on the furnace of the necessarily higher temperature at the end. For making rimming or any other low-carbon steel, the furnace must be in condition to endure a higher heat than when higher carbon steel is being made. Thus for plain steel, con- taining 0.10 per cent of carbon, the furnace laboratory must at the end be about 60 deg. C. hotter (an impor- tant amount), than when 0.60 per cent carbon rail steel is being made, to give the metal the proper tempera- ture. When a furnace, which has been making higher earbon steels, is put to making rimming steel the higher temperature needed for the latter melts a lot of the hearth material which would otherwise have re- mained unmelted. The hearth is thereby scored and wasted away, (which is sometimes an advantage when it has grown too high), and the volume of slag is in- creased for a few heats. The charge should preferably be so proportioned in regard to crude iron and scrap as to contain, when first all melted, about 0.50 per cent of carbon and about 0.20 per cent of manganese. Decarburization should then be as rapid as practicable with a strong boil, slowing down at the end as the desired content of carbon is approached. Every steel melter tries to develop in his bath what he considers a “good” boil, one effect of which is prob- ably to drive out some of the skinhole and central hole gases as already noted. The proper boil for rimming steel at the end is not easily described. It varies with the carbon content and method of casting. Generally speaking, the lower the carbon the quieter the boil with a given slag or rate of feeding ore. For top-casting a livelier boil is demanded than for bottom-casting. The degree of effervescence in the mold follows in a way the degree of boil in the bath. Degrees of Boil Employed The writer has adopted the following names to des- ignate the degrees of boil employed in making rimming steels. Gentle: The bath is one-fourth covered by bubbles. Moderate: The bath is nearly covered by bubbles. Brisk: The bath is wholly covered by bubbles which crowd each other. Strong: The bubbles crowd each other so as to raise the surface of the bath noticeably. Generally speaking, the more active the boil, the larger will be the bubbles, up to 2 in. in diameter when the boil is strong. The finishing boil will vary in a general way from “gentle,” when the metal contains 0.08 per cent of carbon to be bottom-cast, to “brisk” when the carbon is 0.20 per cent and the steel to be top-cast. The proper boil for any given set of condi- tions is quickly learned by one familiar with the art. The desired boil is obtained by (1) a proper charge, (2) proper additions of ore and (3) proper tempera- ture of the bath. If it is too strong, it may be weak- ened by allowing the bath to work without more ore added, or in an extreme case by the addition of crude iron or spiegel. But when the boil is weak, because of low content of carbon, which it may sometimes be, such additions may make it more vigorous. With in- sufficient ore additions, or too much residual manga- nese, or if the temperature of the bath is too high, the boil is likely to be too weak and, as a consequence, too much skinhole gas may be retained in the metal. Its saturation point may then, in the mold, be reached too soon for good practice, so that some bubbles of the gas are likely not to be swept away by the churning but remain near the surface and cause defects already noted. In such a case, even if the steel be cast at the proper temperature, some skinholes may exist in the ingot, as effervescence does not reach its full force instantly, but requires that the metal shall have cooled a certain required amount for the gases to be evolved at the proper rate to give effective churning. The boil steadily becomes quieter, with normal pro- cedure, as the end is approached, which is due partly to the diminishing concentration of carbon in the metal and in part to the lessening amount of oxygen which reaches it. From tests taken and the behavior of the bath after ore additions, the furnaceman knows to what cause or condition to ascribe the state of the boil and how to vary it if needed. If crude iron or spiegel are added near the end, time should be allowed before tap- ping for the boil to resume its normal activity. If the steel is to be top cast, the boil in the furnace must be distinctly more vigorous for a given carbon content than when it is to be bottom cast. A single mold is filled more rapidly than a mold in a bottom- cast group, even when a smaller nozzle is employed, and it is the cooling of the metal which sets free the gases of effervescence as already stated. Top-cast steel 142 a cr re CC OUTROS Ol Ss l™ ' emer we eS UF July 15, 1926 must, therefore, in order to start effervescing prompt- ly, be more fully charged with those gases than bot- tom-cast, for which reason the boiling action of the former in the furnace must be stronger. Regulating Rate of Effervescence For obtaining the desired rate of effervescence in the mold: 1.—Have an adequate boil in the furnace, particu- larly at the end, to secure which it may be necessary to continue additions of ore, in some cases, to shortly before taking the last test or sample. 2.—Limit the amount of stirring given the bath to that required to make it fairly uniform in composition before sampling. Usually one rod before each sample is advisable. 3.—Don't add any gas-solvent at the end or in the ladle unless the boil is too vigorous. If any is added to the bath, as for raising the carbon content, wait before tapping until the boil has resumed its proper activity. 4.—Don’'t have residual manganese over 0.15 per cent for bottom casting, or over 0.10 per cent for top casting. 5.—Have correct casting temperature. Stirring a low-carbon bath causes a great out- rush of gases, manifestly the kind which effervesce in the mold, where they may all be needed. In one plant, which makes both Bessemer and open-hearth rimming steels, a series of heats made simultaneously by both processes were infested with skinholes so that the ingots were too thin-skinned. Effect of Weather For this to happen with both processes at the same time may have been only a coincidence, but it again raises the question as to whether or not the humidity of the atmosphere was exceptionally high at the time because, if so,-the content of hydrogen in the steels may have been proportionately great and its tendency to form skinholes likewise. It is an unsettled point but it may be advisable to have a stronger boil during decarburization in wet weather than in dry, and, fur- ther, it may be that, as a rule, the boil should be stronger in warm than in cold weather, for the reason that warm air usually holds more moisture than cold. Manganese in Rimming Steel Rimming steel has been described as over-oxidized steel, somewhat in accord with the idea expressed by some writers that dead steel is deoxidized and steel evolving gas is not. Though oxygen plays an impor- tant and indispensable part in making rimming steel, to which end it must be freely used, that designation is not accurate. Unfinished steel in the furnace, which contains from 0.10 to 0.15 per cent of manganese, (which it may have and yet boil quite freely) can hardly be over-oxidized. On the other hand, dead steel may be ruinously charged with oxides. Manganese serves to prevent redshortness in rim- ming steel as it does in other kinds but, in making the former, it has also an important effect on the boil in the furnace and on effervescence in the molds, for which reasons its content in the unfinished as well as in the finished steel should be within limits. These have been already stated for residual manganese in the unfinished steel. In finished rimming steel man- ganese should be between 0.35 and 0.45 per cent, pref- erably 0.40 per cent. If with that percentage it shows any redshort tendency it is not well-made in some par- ticular, probably needing longer time in the furnace to clean itself. Too much manganese in the materials of the charge gives too much residual in the bath metal, where it has a quieting effect and the boil is then too sluggish. Such a boil is likely to be followed by too weak effervescence in the mold, in which case the steel is likely to rise before beginning to rim in, indicating that skinholes are being formed near the surface. To control man- ganese in the charge demands that it be right within limits in the crude iron, and the right percentage in the iron depends on the proportion it constitutes of the THE IRON AGE ) 143 whole charge, either. in the. form of pig or “hot” (molten) iron. If the proportion be 40 per cent, then 1.25 per cent in the pig is right. If greater than 40 per cent, then the manganese should be correspondingly less. If manganese in the bath metal be too low for any reason or at any stage of the operation, the desired percentage may and should be made up by adding some, preferably in the form of spiegel. When both killed and rimming steels are made at the same plant, the crude iron for both kinds passing through the same mixer or reservoir, the manganese content must naturally be a compromise, or say 1.50 per cent even, though 1.25 would be preferred for rim- ming steel and 1.75 per cent for killed. Manganese may be slowly oxidized in the bath by additions of iron ore, if carbon in the metal and manganese in the slag both be low, but it is not advisable to make such oxida- tion regular practice. The first basic rimming steel made by the writer had almost no residual manganese, not over 0.02 per cent. It effervesced so strongly that, in a minute or two, it settled to about half the volume it had at the end of teeming when the bottom-cast molds were filled with steel. Each ingot when solidified consisted of a butt attached to a hollow shell or “bootleg” of the shape of the mold interior. The ingot-butts rolled fairly well nevertheless, showing that the steel was not over- oxidized even though it contained so little manganese in the bath. The finished steel contained about 0.35 per cent. In a certain recent practice wherein rimming steel was both bottom and top-cast, the manganese in the crude iron was around 1.60 per cent and the residual manganese in the bath metal at the end about 0.20 per cent. In the bottom-cast ingots the steel had some rising tendency but, when rolled direct, made fair boiler and structural plates. In 3-ton square top-cast ingots, it rose too much and had some small skinholes near the surface which gave rise to blisters when sheets rolled from it were pickled. By cutting down the man- ganese in the crude to 1.25 per cent and by other meas- ures already alluded to, ingots with thick skins were obtained which were almost wholly free from such blis- ters. The residual manganese was then about 0.10 per cent. Effect of High Manganese High manganese in the steel tends to check effer- vescence, as illustrated by the following case: A basic Bessemer plant makes top-cast rimming steel for skelp for welded pipes. The residual manganese in the metal at the end of the after-blow is usually around 0.15 per cent. Ordinarily there is more than ample effervescence so that aluminum is commonly used to check it. When the finished steel contains about 0.40 per cent of man- ganese, about one ounce per ton is added to prevent settling. When the final manganese is high, or around 0.55 per cent, no aluminum is needed as the steel rims in level without it. Intermediate manganese contents take aluminum in proportion. ALCURELONELY UREN DELI OODFDDORON ODEN EHREEDEDESEDEY oF eECEDONEL LON HULCEDEREDUENEIEEEDDe CeROpRERDONORDRNED YY yrH1) FRO reTFeNenO eres teNOD: (To be concluded) OOPRLLEUESUOERLI ERE OEeeoRORORT Locomotive Shipments Better Shipment of 159 railroad locomotives in June is re- ported by the Department of Commerce. This com- pares with 140 in May and with 114 in June last year. All but 15 of the June shipment were for domestic account, the list including 133 steam and 11 electric locomotives. The 15 export units were 12 steam and 3 electric. Shipments for the first half of 1926, at a total of 896, showed a gain of 45 per cent over the 619 of last year. The smallest total for any month this year is larger than the largest total for any of the 12 months of 1925. Export shipments, however, were greater in 1925, the total for six months having been 157 against 112 this year. Unfilled orders at the end of June to- taled 667, which is about equal to the average of the preceding six months. A year ago there were only 411 on order. 144 THE IRON AGE July 15, 1926 MARCH 180 166.236 160 >» g f : ks Fe —_ 140 Ge , Raa = TREND LINE | fess 2 aks ene TT i20 W vy & 100 © we ° w) z 4 ne 8, Poss 80 = > |f ., COMPOSITE PRICE... 92.293 a .. * ; “oF FINISHED STEEL. , 5 e 3 ‘e , 60 = a *. {ites ammmendog, = a %. a “Semen, ett mwe, - 9%, : one © "waseue ge sessseee z ate as?’ iw 2 *“=naee” 40 - Jury 36,7/3 ed Dee ee ee 1923 1920 192) 1922 einstein 1925 1924 1926 June Production of Steel Ingots Shows That the Daily Output Was About 4.8 Per Cent Less Than That of May Decline in June Steel Ingot Output Daily Rate 7488 Tons, or 4.8 Per Cent, Less Than for May—Record for First Half Year HE moderate decline in steel ingot production which set in in April and continued in May was manifest in June. At 144,256 tons per day for the 26 working days, the June output was 7488 tons per day less than the May rate, a decrease of 4.8 per cent. A year ago the June decrease from May was 9635 tons, or 7.3 per cent. For the first six months the daily rate this year has averaged 12,113 tons more than for the same period a year ago but the decrease in operating capacity this year has been much less than it was last year. The production for the half year at 24,260,500 tons exceeds that of the corresponding half year last year by 1,877,- uenennas Production of Steel Ingots (Gross Tons) Reported by Companies Calcu- Approxi Which Made 94.50 Per lated mate Cent of the Steel Ingot Monthly Daily Production in 1925 Production Production Month Open- All All 192k Hearth Bessemer Other Companies Companies Jat 5. 326,846 581,683 13,664 4,150,469 159,633 Fel },023,829 556,031 12,818 3,801,776 158,407 Mar },590,791 635,680 15.031 4,488,362 166,236 April 3,282,435 601,037 13,652 4,123,941 158,613 May 3,201,230° 516,676 10,437 3,945,336 151,744 Jun 3,036,162 498,764 9,441 3,750,653 144,256 t os 19,461,293 3.389.871 75,043 24,260 7 156, 20 1925 Jan ; 689,996 11,960 4,193,281 155,307 Keb 2 602,042 12.998 3,752,352 156,348 Mare , 614,860 13,633 1,194,340 161,321 April 515,715 14,182 3,583,676 137,834 Ma 497,708 13,790 3,454,971 132,883 June 2 176,945 12,490 3,204,451 123,248 6 mx 17,689,358 3,397,266 79,053 22 383.071 144,407 July 2,446,068 457,095 13,547 3,084.472 118.631 Aug 2,698,285 523,734 12,914 3,420,998 131,577 Sept 2,738,673 547,121 13,977 3,489,565 134,214 Oct 3,077,114 584,567 15,624 3,888,814 144,030 Novy 3,092,194 581,347 17,085 3,902,900 156.116 Dex 3.169.796 569,304 15,843 3,970,918 152,728 Total 34,911,488 6,660,434 168,043 4.140.738 141.932 *Revised 50+) tons and is the largest first half year’s production on record and much larger than any second half. The statistics of the American Iron and Steel Insti- tute show that the June production for the companies which made 94.50 per cent of the country’s total in 1925 was 3,544,367 tons. Assuming that the 5.50 per cent not reporting produced at the same rate, a total June output is indicated of 3,750,653 tons, from which the daily rate was calculated. According to the estimates of the institute, June operations were 80.34 per cent of the “theoretical” capacity, compared with 84.51 per cent in May, 88.33 per cent in April and 92.58 per cent in March, the peak of the year. The table gives the reported production by months of the different kinds of steel, together with the esti- mated daily rate for all companies. Slight Decline in Building Construction Building and engineering contracts in the 37 States east of the Rocky Mountains are reported by F. W. Dodge Corporation to have amounted in June to $547,- 800,000. This was a drop of nearly 1 per cent from May and of 2 per cent from June, 1925. As for many months past, residence construction, with $237,700,000, formed much the largest item. Industrial buildings at $54,500,000 provided 10 per cent of the total and continued at the low level of the past year or more. Commercial buildings amounted to $68,000,000. The area covered by these figures represents about 91 per cent of the total construction volume of the country. A new record was reached for the first six months of the year, the total having been $3,113,000,000, com- pared with $2,749,000,000 in the first six months of 1925. The increase was 13 per cent. Only in the Pitts- burgh district was an increase registered in June over both the preceding month and June, 1925. In each case the present figure shows a gain of approximately 50 per cent. It registered $95,061,000. Of this amount $22,177,000 was for industrial buildings, this figure being nearer to the total for residential building than in any other district. —~e- Orevod coeaevrew +a Serving Two Plants with Coke Different Coal Mixtures Required for Needs of the Two Furnace Groups—All Coke Made in Same Ovens BY DANIEL M. RUGG* nace, and not merely to supply it with coke. Some blast furnace operators feel occasionally that this is not the case and that they are merely being supplied with coke, either good, bad or indifferent, as the case may be. Occasionally a single coke plant supplies two or more groups of blast furnaces with futl. This situa- tion makes it more difficult for the coke plant operator to give either blast furnace group the best service, or service which he might be able to give if considered individually. The above opinion is not unanimous among operating men, as some feel that “good coke” is “good coke,” irrespective of size of furnace, kind of iron being produced and operating methods of the management. I would like to recount here an experience which we had in Buffalo, which I hope will bring out discussion that will prove interesting and valuable, even if it should be decided that I am not correct in my opinion. i is the duty of a coke plant to serve the blast fur- Three Batteries of By-Product Ovens The plant of the Donner-Hanna Coke Corporation at Buffalo consists of three batteries, each of 50 11%- ton Koppers ovens. The usual coking time is about 14 hr. 18 min. gross, or 252 ovens pushed in 24 hr. There is one 2700-ton coal storage bin, between No. 2 and No. 3 batteries, which has one vertical partition forming a “small” bin of 900 tons capacity and a “big” bin of 1800 tons capacity. There is a coal storage yard with a capacity of 150,000 tons, so arranged that each kind of coal may be unloaded, stored and reclaimed separate- ly. There are four mixing bins under the Bradford breakers. The desired coal mixture is fed from these bins into the hammer pulverizers and from there con- veyed to the oven storage bin. There is a single coke wharf and one screening station. A rotary grizzly passes all coke over 3% in. through a roll crusher. Furnace coke is screened over a cascade bar, grizzled space between the bars being about 1% in. in the clear. The screening in general is good but by no means per- fect. Furnace coke from the bar grizzly is fed into cars by a boom loader. While this company does some out- side selling, the bulk of its coke production goes to the two groups of blast furnaces. , Two Groups of Furnaces In Group No. 1 there are two blast furnaces with general dimensions as follows: Stack Fur- Hearth Bosh Height Tuyeres Line nace Ft.In. Ft. In. Ft. In. Ft. In. Stoves No. 1 17 6 216 900 12 16 6 4 McClure 3-pass No, 2 17 0 210 900 12 16 0 4 McClure 3-pass No. 1 furnace has a McKee distributer. It was blown in during August, 1924. No. 2 furnace has a stationary top and a rather small hopper. This furnace was blown in during March, 1920, and had made 880,000 tons of iron at the end of the run described below. These furnaces are equipped with Brassert gas washers. During all except the first month of this period No. 2 furnace was on basic iron. No. 1 furnace was on foundry iron, except as noted in Table I. While the amount of scrap used on No. 2 furnace was greater than that on No. 1, the quantity used on each furnace throughout the period was consistently uniform. *Koppers Construction Co., Union Trust Building, Pitts- burgh. 145 In Group No, 2 there are three blast furnaces hav- ing the following dimensions: Fur- Hearth Bosh Height nace Ft. In. Ft. In. Ft. In. Tuyeres Stoves 2-pass side combustion 18 x 80 ft. | 1 2-pass central A i3’ 9 19.3 80 3% 16:52 combustion 18 x 80 ft. 2-pass side combustion { 22 x 90 ft. LB 14 6 19 O 80 10 10 4 2-pass side combustion 20 x 80 ft. Se 14 6 5 33 10 3 3-pass McClure, 18 x 75 ft. These furnaces were making foundry or malleable iron, an indicated in Table I. No scrap except that pro- duced by the furnaces themselves was used at any time. te to Trials of Differing Mixtures — Both groups of blast furnaces had been in operation for some time before the coke plant was built. The coke plant was put into operation late in 1920 and from that time until late December, 1924, a number of dif- ferent coal mixtures were tried and the results obtained at the furnaces varied considerably. During practi- cally all of this period, the same coke was shipped each group at any given time. There were occasions when one group of furnaces was doing well in coke consump- tion and iron produced. There were occasions when sat- isfactory results were obtained on the other group. There was not a single period when both groups were doing good work. There were, also, some occasions when both were anything but pleased with their coke. The coal supply was purchased on the open market. Its quality varied considerably, often because of fattors entirely out of control of those in authority at the coke plant. The general tendency was toward better and more uniform coal supply and, in the opinion of the coke plant operators, the coal supply on Dec. 1, 1924, was about the best in the history of the plant. Discordant Results in Late 1924 Table I shows the operating results on each group of furnaces during the months of July to December, 1924. The analyses of coal and coke and the coal mix- ture used are given, for the same period, in Table II. Compared with past practice, Group No. 1 was do- ing good work and the results seemed to be improving. The manager did not want to make any change in the coke. Group No. 2 was going from bad to worse and the results for six months, from July to December, 1924, were about the worst in its history. “A” furnace was blown out the last of September and was being relined. “B” furnace was in bad shape and it seemed that she would have to be blown out very soon. Top heats were running up to 600 deg., instead of the usual 300 deg. Coke plant operation was uniform and we felt that we were doing everything in our power to produce good blast furnace coke. We were perfectly aware that good blast furnace coke meant good operating results at the furnaces. Experiments to Obtain Density We were told in no uncertain terms by the manage- ment of Group No. 2 furnaces that our coke was very CE (Continued on page 192) Fig. 8 ILLOWING is the second part of the paper on “Hypoid Gears,” presented by Arthur L. Stewart and Ernest Wildhaber of the Gleason Works, Roches- ter, N. Y., at the summer meeting of the Society of Automotive Engineers, which was held at French Lick Springs, Ind., June 1-4. The first part of the paper appeared in THE IRON AGE of July 8, page 84. The two methods of production of hypoid gears developed by the Gleason Works have already been mentioned in the first part of the paper. The earlier method, in which the gear is cut with- out generating roll, is theoretically accurate; that is, it does not contain the least theoretical error or ap- proximation. This method has been discontinued in favor of a newer one, that gives as good or better re- sults on account of its increased flexibility, and which incidentally permits the use of the present gear gen- erating machines on the gears. We will limit our ex- planations to this method. It will be seen that the method has been worked out mathematically to a high degree of perfection and is not based on any assump- tion of which the effect is not entirely known. Al- though somewhat long in figuring, this method is very pract@®al in operation and permits refinements not previously available. According to this newer method, the gear is cut exactly like a spiral bevel gear of the same pitch angle. In the production of the pinion a Gleason generator with additional adjustments is used, and the pinion axis is offset from the axis of the cradle. The cutter is of the usual Gleason type having straight cutting edges, which are at an angle to the axis of the cutter. Preferably, different cutters are used on gear and pinion. One gear cutter and one pinion cutter can cover all cases. It is not necessary to use cutters with varying amounts of pressure-angle correction, as has been the practice with spiral bevel gears. During the generation, the cutter represents a crown gear with an offset axis and conjugate to the same pinion that is also conjugate to its known mating gear. A generating motion is provided between the cutter and the pinion blank as if the pinion would roll on said crown gear. Analysis of Mesh Between Pinion and Gear We will now briefly analyze the mesh between a hypoid pinion and its mating gear: In Figs. 3 and 4 (in the first part of the paper), the mesh between a pinion and a crown gear has been illustrated. It has been found that, if the teeth extend along certain pitch lines, either side of the teeth meshes along the same line of action in the pitch plane of the crown gear; that this line of action c, Fig. 4, is inde- pendent of the pressure angles, and that the projected tooth normals, i and o, of either tooth side intersect at the same point, j. Somewhat analogous conditions can be determined in the present case, in which the mesh in a pitch plane Explain Manufacture of Hypoid Gears Gleason Engineers Outline Method Which, for Most Part, Employs Same Equipment Used for Spiral Bevel Gears between two hypoid gears is considered, the axes of which are inclined to the pitch plane. In Fig. 6,/ and J are pitch surfaces of gear and pinion, which are tan- gent to a common plane selected as the drawing plane of Fig. 6. K and L are the projected axes of gear and pinion, and also the contact lines between the pitch plane and the pitch surfaces J and J. However, in contradistinction to the former case of pinion and crown gear, the line of action of the same character cannot extend along line L, but extends along” a line T, which is inclined by a small angle Y to line L. The relation between the location of points j and t can be determined in a manner analogous to the one ex- plained with reference to Fig. 4; that is, point 7 may be determined by drawing line N connecting points g and t and by drawing line V through point A at right angles to line of action T. The intersection point P is then projected to normal i thus locating point j. Instead of using a graphical solution as illustrated by the diagram, the location of this point and of all other points can also be determined by calculation, which is more accurate, and which is exclusively used at the Gleason Works. Pressure Angles Change The normal pressure angles along points Q of line of action T, that is, the inclinations of the tooth nor- mals at points Q, can be determined from the known structure of the gear and the cutter which produces it. They change slightly along the tooth and are also different from the pressure angle of the pinion cutter except at point Ah. In order to cut a pinion with pres- sure angles exactly matching those of the gear, along the whole length of the teeth, another line of action R is determined for the mesh between the pinion and its crown gear, which is represented by the cutter. The mesh ‘during generation extends, therefore, along a line R, different from the line of action T of the pair of hypoid gears. Line R is inclined by a small angle X to line L. The final step is to determine a crown gear, which is able actually to mesh along the figured line R with the pinion, and which contains tooth sides which are conical surfaces of suitable diameter. A tooth side of this crown gear is then represented by a cutter, and the pinion is generated while meshing with this imag- inary gear. With the developed method, tooth surfaces may be produced which match those of the mating gear along the whole length and along the whole depth of the profiles. However, for reasons of adjustability, that is, to provide a certain range of running positions and to allow for non-rigid mounting, the bearing area of the teeth is preferably somewhat restricted, especially in the case of rear-axle drives. Any desired deviation from full bearing may be obtained lengthwise of the teeth and on the depth; that is, on the profile. More curved or less curved tooth profiles on the pinion are obtained by changing the offset between the pinion and the crown gear, after refiguring the settings. It has been pointed out previously that on the tooth side of the pinion, which during the meshing is opposite to the axis of the gear, an increased offset requires a 146 July 15, 1926 flatter profile; that is, less curvature of the profile. If, therefore, on this side, which is usually the drive side, the offset is increased during the generation, the resulting profile will be flatter; and if the offset is re- duced, the resulting profile will be more curved. The opposite holds true for the tooth side of the pinion, which is on the side of the axis of the gear or crown gear. Bias bearing, that is, a tooth bearing, which extends obliquely across the tooth surface and which has occurred and been found objectionable in certain cases of curved tooth gearing, results when the pressure angles of gear and pinion do not match along the whole length of the teeth. The pressure angles of _ - =e hypoid gears are made to match along the whole length of the teeth and bias bearing is thus eliminated. Another feature illustrating the flexibility of the method of cutting is the fact that the tooth bearing of a pair of hypoid gears under pro- duction can ‘be raised or lowered, or moved endwise, by simply chang- ing the cutter set- ting. If it is de- sirable, for in- stance, in order to counteract harden- ing changes, to shift the - tooth bearing, the tooth bearing can be placed readily on any desirable spot whatsoever on the tooth surface. Production op- erations are, in general, the same for hypoid gears as for spiral bevel gears. This includes preparing the blanks, cutting the teeth, hardening, grinding bores, shanks, etc., and lap- ping the teeth. The blanks are turned to different dimensions, being larger in the case of the pinion, and of slightly different face and back angle and outside diameter in the case of the gear. Machines for rough- cutting the gear and pinion and for finish-cutting the gear are the same as used for spiral bevels. The pinion finish-cutting machine has additional adjustments for setting purposes, after which the cutting operation itself is the same. The added settings are a vertical adjustment of the work spindle in accordance with the offset of the pinion with respect to the gear, and two angular adjustments of the cutter spindle, about hori- zontal and vertical axes respectively. These adjust- ments are clearly seen in Fig. 7. In the testing and lapping operations, machines must have the same off- set of work spindles as the pinion and gear shafts are to have in final assembly. Fig. 8 shows a pair of hypoid gears on the testing machine. In cutting the pinions, it is found advantageeus to cut the top side on one machine and the bottom side on another machine. This saves time, as nearly all the machine settings have to be changed in going from the top to the bottom side. Pinion cutters are then made with all outside or all inside cutting edges, which permits a speeding up of the machine. Cutters of 9 in. mean diameter are used in all cases of hypoid gears up to date. It will be seen from the above that production costs of hypoid gears will vary but little from costs of spiral bevels. Cost of blanks will be changed only in the case ot THE IRON Fig. 7—Hypoid Pinion Finish-Cutting Machine. The equipment for rough-cutting the gear and pinion are the same as used for spiral bevel gears AGE 147 of the pinion, where the increase in diameter will call for a slightly larger forging. If advantage is taken of the additional load-carrying capacity and gear diam- eters are reduced, this will more than offset additional cost of pinion blanks. Cutting cost for the pinions will be slightly less on account of using all inside and all outside blades on the cutters. Ring Gear of Smaller Diameter Influences Chassis Design The use of a ring gear of smaller diameter and the location of the rear end of the propeller shaft will have important influence on chassis design. On account of the capacity of hypoid gears for greater trans- mitted load, a de- crease of about 10 per cent in ring gear diameter can be made without increasing unit stresses. This makes possible a greater road clear- ance. The lowered position of the driving pinion re- moves the chief ob- stacle to lowered floor boards at the rear ends. Advan- tage can be taken of this to lower the whole body. A very practi- cal point of advan- tage for any pres- ent user of spiral bevel gears, who is considering adopt- ing hypoid gears, is that the change can be made with slight change in manufacturing method or equip- ment. As has been pointed out already, the finish-cut- ting of the pinion is the only major operation requiring machinery differ- ent from that used for spiral bevel gears and pinions. Various Expanding Uses of Sheet Steel A Kansas City firm has introduced sheet steel lunchstands. They are regarded as offering the first sure protection against rats that the lunchstand pro- prietor has yet found, and are easily moved from place to place. The Atlantic City restaurant of Chicago has found permanent satisfaction, it is reported, in sheet steel counters. Both restaurants and lunchstands ap- parently find desirable qualities in sheet steel. Other companies have begun to use sheet steel in building waiting stations for buses and interurban cars. The rapid growth of bus transportation in the country promises a profitable market. L. L. Huntington has reported interviews with Marshall Field & Co. and other western office furni- ture dealers to the Sheet Steel Trade Extension Com- mittee of the National Association of Sheet and Tin Plate Manufacturers. He finds that the old prejudices are being broken down rapidly in this field. Steel filing cabinets have nearly displaced wood, and prices are falling with increased buying. Steel desks and tables were introduced later than the filing cabinets and are now beginning to sell readily. Furniture deal- ers report complete stocks on hand and are beginning to push their sales. Mr. Huntington sees a similarity in the present position of steel desks with that of filing cabinets ten years ago, and predicts rapid growth. 148 Industrial Truck with Gasoline-Electric Power Plant The Ready-Power Co., 5626 McGraw Avenue, De- troit, has developed a gasoline-electric power plant for lift and load carrying trucks for industrial purposes. The unit consists of a four-cylinder, water-cooled Con- tinental Red Seal motor driving a low-voltage genera- tor in a steel compartment of such size that it may easily be mounted on trucks. The motor, operating at a constant speed except for idling, is under governor control, designed automatically to adjust the engine load to truck requirements. The appliance is made in two similarly constructed models, on2 to meet the needs of trucks equipped with 24 to 30-volt motors, and the other for 48-volt motors. Truck Loader of High Capacity George Haiss Mfg. Co., Inc., New York, is the maker of the truck loader here illustrated. It has a capacity of 4 cu. yd. per min. A bucket width of 37 in. is achieved by two strands of buckets mounted on four strands of chain. Power is furnished by a 37-hp. Wau- kesha engine, and a transmission box incloses the clutches and gears. The machine is equipped with caterpillar traction. This Haiss Truck LoaderHasa Double Strand of Buckets, Giving a Bucket Width of 37 In. THE IRON July 15, 1926 AGE The Gasoline- Electric Power Unit Has Been Deveioped for Trucks Having Electric Motors The elevator unit is pivoted on an A frame, and a raising and lowering device actuated by a hand wheel through a worm and gear jack knife makes it possible for one man to raise or lower the elevator. The loader clears a path 9 ft. wide, and the slow speed mechanism is designed to allow crowding into a pile at 39 in. per min. There is a 10 ft. clearance under the spout. A series of management meetings held at Ohio State University, Columbus, late in October, is reported in detail in four pamphlets comprising No. 22 of Vol. 30 of the Ohio State University Bulletin. The pro- ceedings appear in four parts. One covers production management and time studies; another, accounting; an- other, marketing, and the fourth, office management. Part II, which is that reporting the meetings on pro- duction management and time studies, is a pamphlet of 75 pages and includes papers by the following authors: E. H. Tingley, Delco-Light Co., Dayton, Ohio; Stephen DuBrul, Pyro Clay Products Co., Oak Hill, Ohio; J. D. Towne, Dayton Steel Foundries, Day- ton, Ohio, and Willis Wissler, Bureau of Business Re