The Iron Age 1921-09-08: Vol 108 Iss 10

aaqaacaanwt"s™ = THE IRON AGE STABLISHED 1855 New York, September 8, 1921 VOL. 108: No. 10 Electric Furnace Operating Experiences Experiments with Three Forms of Furnace Bot- tom—Methods of Building Bottoms—Experiments with Roof and Sidewalls—Metallurgical Features ereat need for a melting im which would furnish the ired steel. Many orders ed such rigid specifications they could only be met by made either in the electric ice or the crucible. Elimi- iting the crucible due to its small tonnage and high cost, remained only the electric The tests of this steel, tonnage possible in a given |, and its commercial costs, ed the eyes of manufac- to its peace time possi- Its scope or adaptability making of alloy steels, astings, iron castings, etc., come to be thoroughly nized, and it has become f the accepted factors in teel industry. Many new furnaces have nto existence and many tives have adopted the idea ll they need to produce of exceptional quality is electric furnace. The per- equation is either ignored sed over as a minor point. ‘ollowing paper is an at- to show what highly results can be obtained same furnace under dif- _ conditions of operation. The points shown are not forward as anything t merely to bring before es of the electric furnace ry some points usually re- gar as minor, yet points Fig. the 1—Arrangement of Electrodes for Burning Bottom Furnace and Equipment _ ‘he furnace discussed in the following article is a al 6-ton Heroult, basic lined. t used throughout is of General Electric make. n+ Sacramento, Cal. of increase of its career. Under the conditions of war specifications there the nay mean commercial success to a new under- Furnace by Bit The electrical lurgist and electric steel superintendent, Southern 581 work. BY LARRY J. BARTON* URING the last five years the electric furnace 1) has shown the greatest by Sintering de-gasification. Bit This furnace is working on steel castings and high- grade rolling and forging ingots for general railroad The scrap used is not selected, but is taken as it comes from the road, con- sisting of such material as old track bolts, spikes, tie-plates, old castings, forge flashings and butts, borings and turnings, etc. When the furnace was about to be put into operation great consideration was given as to whether an acid or a_ basic process was to be used. The ad- for the acid were hotter and cheaper steel and greater tonnage in a given period. Against this were the disadvantages: selected scrap must be used to meet specifica- tions, due to the inability to do any refining of note on an acid bottom; specifications and analy- harder to meet with constant exactitude; alloy steels cannot be very satisfactorily made, and can never be remelted to save alloys; no iron refining can ever be done; power surges vantages process ses are and even control give more trou- ble than on a basic bottom. As the scrap to be used was high in phosphorus and sulphur, due to large quantities of wrought iron, it became impera- tive to use the basic process. Against the disadvantage of higher cost for this process were the ability to make any analysis with ease; great refining possi- bilities; easier power control; elimination of power surges with high peak loads; reclama- tion of alloy steel scrap; and most important of all, complete Basic Furnace Bottoms There are three methods in use for the making up of a basic bottom. 1. The bottom is sintered in bit by bit, being always under the heat of the arc. 2. The whole bottom is rammed into place, the fur- nace filled with coke and heated white hot for from a so yeti te<tr tg aigaieamiaaae* Soom atie-Daiechan 7 A ae sa signees ae ee 3 % eg mans ns ag Be | el ES: RD PRA. aS weccnefpaaetiald oh eA fe.” ee Ney ee eee oe oa ~ 2 RDP ELT COR Hasse REL tows a's ie 582 THE IRON AGE September 8, 1921 8 to 24 hr., burning in the complete bottom at one operation. 3. The bottom is rammed in an inch or two at a time, and then burned as in method 2. Believing that the better the bottom at first, the less trouble in the future, we used the first method. This method is one which, if properly done, will give Fig. 2—Dead Corners of Fur- nace Bottom Filled with Rammed Mixture of Mag- nesite and Tar a bottom of solid material all the way through, with- out any foreign material such as coke from tar, as would be obtained in a rammed bottom. Then there is no danger of the bottom rising in layers as is pos- sible when put in by ramming a layer at a time. The following is a log of the bottom burning: Electrodes set on bottom as shown in Fig. 1. Dead cornérs of bottom filled with rammed mixture of magnesite and tar, as shown in Fig. 2. 4:30p.m. Current on at 2000 amp.; 500 kw. ©9:30p.m. Current 3000 amp.; 700 kw. »:30p.m. Current 4000 amp.; 900 kw 30 p.m. Opened doors for first time after start. raised electrodes and inspected walls On lowering electrodes the plug in bottom connection slipped. 05 p.m. Current on again at 900 kw. First addition of magnesite-basic open-hearth Slag, 4:1, made around corners; 1200 kw. Walls glistening. .and1:00a.m. Additions made regularly as long as previous layer had become thoroughly sticky and pasty. Bottom as high as possible on this set up. Shut off current and pulled electrode stubs. Bottom looking fine, walls have run slightly. Set Up. -m. Current on, 500 kw .m. Increased to 600 kw. .m. Increased to 750 kw. m. Increased to 900 kw. Furnace getting very hot .m First addition of 6:1 immediately to rear of No. 2 electrode, where are is directly striking Walls glistening. Additions now being regularly made of 6:1. 9:40p.m. Cut power to 700 kw. 50 p.m. Cut power to 600 kw. :40 p.m. Cut to 500 kw. From this point used all mix- ture in a moist condition and used spoon for all wall touching. All additions being made with current on. 3:40 p.m. Current off and stubs removed. sottom looks fine and hard as rock. Bottom 8 in. thick at center. Total time 19 hr. This bottom has been in use for a year and a half 24-hr. operation, and has not given a bit of trouble. Fig. 3—The Bottem of the Furnace When First Put Into Use. Took long to secure pouring temperature. Capacity 6 to 7 tons While on the subject of bottom making, it might be a good thing to mention the use of the cement. gun. While not particularly applicable on such a small in- stallation as ours, in the case of a 75 to 100-ton open hearth furnace, it has proved to be a wonderful aid 2 in bottom making and patching between heats. Th: best open-hearth bottoms are those put in the sam: way as indicated by the preceding log. The old wa, was to have a gang of men throw the patching materia! across the furnace with shovels. For this purpose the cement gun is now coming into large use. Some of it; advantages are: The bottom can be made up while the gas is on and the doors down; there is practically no wasted material; the material is shot precisely to th: points where wanted; the men can stand away from the heat, and only two mén are needed to handle the appa ratus; the time between heats can be materially lowered, Experiments on Bottom The bottom when first put in was as shown in Fig. 3. After following results very carefully on this shape of bottom, we allowed the bottom to “build up” to shape shown in Fig. 4. When our figures from this method were enough to prove the results, we changed to the shape as shown in Fig. 5. During this period we ran heats of 5 to 8 tons, keeping careful figures on all such points as time of melting down, refining, etc. From this mass of data we obtained the following points: 1. Bottom No. 1 melts down fastest. It takes longest to heat to the pouring temperature. Refining is not as good as No. 3. Trouble is experienced with side walls digging opposite the arcs. Due to its in- creased depth, there is a greater length of electrode necessary between the roof and the bath during melting down. In other wotds, due to the electrode’s digging deeper, the holders must be fastened to the electrode Fig. 4—The Shape to Which the Bottom Shown in Fig. 3 Was Built Up. Proved of no value in comparison with other bottoms. Capacity 5 to 6 tons higher up. This results in a greater amount of elec- trode becoming heated and results in greater electrode consumption. 2. Bottom No. 2 proved to be of no value at all, in view of the working of the other two. It took greater power, more time, more electrode consumption in pro- portion, to turn out the smaller heats than with the larger heats on the other shape bottoms. 3. Bottom No. 8 proved to be the best all around bottom. While it did not melt as fast as No. 1, the total time per ton was less, due to shorter time of re- fining and superheating. Absolutely no trouble was experienced with side walls, and refining was possible without extra trouble, down to 0.005 per cent sulphur. The main point found was that with a bottom shaped as No. 3 it was possible to melt and pour 8 tons of metal, in the same time as would take for 6.5 tons on bottom No. 1, or 5.5 tons on bottom No. 2. On this bottom we have made 8-ton heats, for steel castings, in as short a time as 3 hr. 5 min. from the time cur- rent was put on until pouring. Furnace Walls Having determined the shape bottom which gave US the best results, our next step was made on the side walls. These were of 18-in. silica brick, two courses; laid flat. The bricks were made by the American Re- fractory Co., analyzing about 90 to 95 per cent silica, September 8, 1921 and have proved very reliable. These bricks were laid perfectly dry and completely up to the roof ring. After running several linings we changed as follows: The lining next to the shell was run all the way to the roof, while the inside lining was run only as high as the arches. This made an 18-in. lining up about half way, and a 9-in. lining from that point to the roof. After obtaining our figures on this style of wall, we substituted magnesite brick for the silica brick, in the Fig. 5—Shape of Fig. 4 Bot- tom Changed to That Here Shown. Proved to be the most satisfactory. Capacity 8 to 10 tons inside lining for a space of about 2 ft. directly opposite each electrode. Then we did the same thing, using carborundum brick opposite the electrodes. Our next step was to use only 9 in. of brick in the walls, trying both silica and magnesite. In the near future we ex- pect to try this with carborundum brick. From our trials we found that: 1. Both with full 18-in. walls, and with 18-in. walls only half way up we experienced the trouble of having the brick burn through opposite the arcs. This is shown in Fig. 6. This weakened the wall and we had great difficulty with the upper part of the wall falling n when pouring. To overcome this we moved the elec- trodes 2 in. in toward the center of the furnace, but ill had the same difficulty. 2. Magnesite brick opposite the arcs hold up much mger than the silica brick, but tend to spall severely, ming off in pieces 2 in, thick. Carborundum brick burned off 2 in., while mag- site brick under them burned 9 in., and silica brick ve burned through 18 in. These bricks gave excel- t service, but at a price of $1.75 per brick, the cost prohibitive. We expect to put in a full wall of these cks to determine exact costs of same. 1. Best results were obtained with only a 9-in. wall. While the loss of heat was greater, by lining a little ‘tener this was entirely overcome, and the extra cost rick was saved by the ability of repairing in shorter e than when a full 18 in. was used. While there are many other combinations of brick could have been used, we feel that we have tried enough to be able with certainty to foretell the tion of our furnace weeks ahead. We believe as good results are obtained with only 9 in. of Ss with 18, figuring on a yearly basis. Furnace Roof roofs are made up in the standard way, using mon shapes of silica brick. The only experi- tion done on the roof was trying out different ‘s from the bath. We have tried with the roof “ng on the roof ring of furnace; with it 2% in. r; and with it 5 in. higher. We find that by he roof we save enough to obtain a few heats ‘om each roof, but it takes longer to get out the Our present practice is to rest the roof directly ring. We are now collecting figures on the on of a Griffin patent roof, which was put into mn 1 a few weeks ago. THE IRON AGE 583 Carbon electrodes of 17 in. diameter and graphites of 10 in. diameter have both been tried with the balance in favor of the carbon. Our main objection to the graphites is the fact that they are too fragile and do not stand up under tonnage work. In addition they require too much lowering in the holders, causing a large amount of delays. With the carbons we found that they would melt quicker, did not break so much, required less lowering, gave better power figures, and in general under our conditions proved much better. Slags The slags are the heart of the electric furnace process. Under an oxidizing condition phosphorus is removed, while under a reducing condition sulphur is eliminated. As these impurities are removed by the slag it follows that the greater the amount of slag, the larger the amount of impurities that will be re- moved. It also follows that the greater the amount of slag, the greater the power necessary to melt and keep this in a molten condition. It normally takes about 530 calories to melt low carbon steel, while it takes about 650 calories for the same amount of basic slag. Therefore the slag requires more heat for the same amount than the steel, and all heat or power wasted in heating unnecessary amounts of slag is money wasted. What Is Correct Amount of Slag? The problem therefore is to ascertain the correct amount of slag to use to eliminate the impurities. As the base of the slag is lime, and this is practically in- fusible, there must be something else added to form a slag with the calculated weight of lime. There are two main materials, silica sand and fluorspar. Of these silica sand is much the cheaper, and if possible should be used in greater quantity than the fluorspar. Now the question comes up, “How much of. these shall I use?” One naturally wishes to add enough to make the slag thoroughly fluid and yet not make it watery or tend to go acid, nor does one want to have a thick viscous slag. After a large number of trials and experiments on this subject, we have adopted the following: Lime, 2 per cent of the charge; sand, 20 per cent of the lime; spar, 10 per cent of the lime; ground coke, two large scoops to each side, or four large scoops to the total. For our first slag we use 2 per cent of the ‘charge lime only, the lime having enough dirt and sand from the scrap to flux it thoroughly. The second slag material is added half at a time, being thoroughly mixed on the Fig 8 Silica Brick Walls Burned Through Opposite the Arcs < ~ SAW SVAN d STs Das or & LASS OAS floor. In a large majority of cases this mixture will give a finished slag in 20 min. to half an hour. If anything this slag tends to come up a little thick, requiring one scoop of about 25 lb. of spar to finish it. The amount of ground coke will not affect the carbon in the metal and is the principal cause for a quick clear- ing of the slag. We have run hundreds of heats call- oP OLS eta ne Set ere = ow eae aay rote i 584 THE IRON AGE ing for under 0.10 per cent carbon with this mixture and have seldom -had an off analysis. Alloys All our alloys are added to the furnace. Our ferro- manganese is added immediately after slagging off. Then when the slag has cleared and powders on ex- posure to the air we add the silicon. If alloy steels are being made, then is the time to add the alloys. This applies to chrome, chrome-vanadium, high silicon, man- ganese steel, and any others in which the alloy itself is likely to become oxidized. Copper and nickel can be added in the charge with no appreciable loss. Im- mediately the final alloys are added, the slag must be given a heavy dusting of ground coke to prevent any possible reoxidization. On heats under 0.10 per cent carbon, we add %4 lb. of aluminum per ton of metal, in the ladle, to prevent any rising in the molds. Pouring We do not use any skimming gate when pouring. We do not claim that this is the best of practice, but find that the class of steels we make do not require such precautions. In a case for very high grade forg- ing ingots, for instance, just a few minutes before pouring we throw a scoop of lime on the edge of the slag just inside the tapping door. This thickens the slag enough to act as a skimmer, the slag following into the ladle after the greater part of the metal. On heats of this kind we tap at a much higher tempera- ture than required, add a few pounds of fluorspar in the ladle, and hold the metal in the ladle 10 or 15 min. before pouring any ingots. The fluorspar tends to bring any foreign matter to the top during the period when holding. We have made numerous tests to determine segre- gation but have never found any to amount to anything. We lay this to the fact that the steel is completely finished before it ever touches the ladle, the pouring operation serving merely further to mix it. Conclusion After an intensive series of experiments we have adopted the following conditions as being more economi- cal and efficient in every manner, under our conditions of working: 1. The bottom shall be nearer the shape of a saucer than a cup. 2. The thickness of the bottom shall be % in., and shall be made of double dead burned magnesite, sin- tered in bit by bit. 3. The walls shall be of silica brick, 9 in. thick. 4, The walls shall be laid either dry, or with a thin coating of silica cement. 5. The roof shall rest not over 2% in. higher than the roof ring, preferably on it. 6. Electrodes shall be of amorphous carbon, 17 in. in diameter. 7. Dephosphorizing slag shall be 2 per cent of the charge lime. 8. First slag shall be added during melting down, never added on the hearth. 9. Deoxidizing or final slag shall consist of 2 per cent of charge lime; 20 per cent of lime sand; 10 per cent of lime fluorspar; 4 scoops ground coke. 10. This final slag charge shall be added a few min- utes after slagging off, one-half at a time. 11. All alloys shall be added in the furnace, and steel shall be in a finished condition before the ladle is called for. In closing, the writer again wishes to reiterate that the ideas expressed in the foregoing are not offered as a text on electric steel, but merely as a few sugges- tions of the great amounts of varying results which September 8, 192) can be obtained with the same apparatus, showing th, great importance of the human equation. Our cond; tions as we found them may be a great deal differen in another shop under different conditions, but th. record of the experience may serve as a guide to meet ing difficulties as they come. In the face of the prese: competition it is the shop with the best and mo: efficient “system” which will win out. Causes and Cures of Depression In discussing the current business situation, Pr dent F. C. Biggert, Jr., United Engineering & Found, Co., Pittsburgh, states—“‘Always it is the arous of the national consciousness to the fact that son thing is out of joint, or likely to go out of joint, t! causes depressions. This time it is the foreign sit tion which looms largest as a disturbing factor. situation is the inevitable consequence of our y commerce; its correction will be by the inevitable | eration of the law of compensation, and a very | time, a great many years, will be required to re-es lish the balance. “To be sure we can recover our breath and go aly within our own country and be prosperous for a lo) time, without any considerable ‘commerce with oth: nations; but we must recognize and obey the natur conditions to be successful in this. “We must buy from outside nations more than sell to them, and to offset this purchase of for labor, we must occupy ourselves in the developm: of our own country to the highest possible state economy. We need railroads and railroad equipment improved highways, development of waterways, hous and farm machinery. We should develop our wate: powers to the end that less coal be consumed ar should burn our coal more efficiently where we must burn it. We should study the economical use of all our labor and materials. “Under our present conditions it will be difficult to do these things. Wise counsel and judicious gove ment will be necessary to their proper consummat but they are the key to our success in the future.’ Improvements of American Roll & Foundry Co A pregram of improvements at the American Kk & Foundry Co. department at Canton, Ohio, of United Engineering & Foundry Co., Pittsburgh, start in 1920, is now nearing completion. It includes extension of 120 ft. to the roll and machine shops, 200 ft. to the foundry, new pattern shop, new black smith shop, modern office building together with vari- ous additions to equipment, including a number of cranes, roll lathes, new type air furnace, with wast heat boiler, and Fuller coal pulverizing equipment. The plant produces gray iron castings, sand and chilled rolls, and is equippéd for and makes a great many rolls for rolling iron, steel, spelter, brass, copper and alloyed metals, and also makes a specialty of rolls for rubber and paper mills. “Peds” to Attach Trim to Concrete The General Fireproofing Co., Youngstown, Ohio, !s introducing to the building trade a “ped” or spot ground for attaching wood and metal trim to walls, and screeds to concrete floors. A ped consists of a nailing block of wood forced into a circular metal plate. The woo’ block, 2 in. in diameter, is treated to prevent rotting or swelling from moisture. The metal plate, 3% '" in diameter, is painted to prevent rust and perforated with %-in. holes. The ped is bonded to the wall w'th plaster or to the floor with cement, and the plaster 0! cement comes through these holes and keeps the ped firmly attached to the basic surface. When the plaster or cement has set, the walls ar plastered flush with the top of the wood nailing block. and the floor screeds are nailed down. The peds for™ solid, permanent spot grounds in the walls for the s° cure fastening of wall trim, and a firm foundation !0' the wood floor. Foundry Irons for Particular Uses Differentiating Characteristics of Gray Iron, Mottled, Chilled or White—Skill of Manu- facture—Analyses for Certain Castings . SS ee (Fe—Fe;C—C) when compared with white iron. That is: at different prolonged cooling tempera- : ‘ures and concentrations, sufficient time elapses for its tituent parts—more particularly carbon—to reach tate of comparative equilibrium with reference to leculag adjustment. Therefore, when gray iron is mitted to cool gradually, its molecular structure \ws more closely the curve lines of stability. During ooling periods the iron carbide has sufficient time lecompose naturally into iron and carbon—part of arbon separating out as particles of graphite. The ence of this graphitic carbon in cast iron controls eutectic, or melting point, and largely determines its ty and freezing point. That is: the melting point raphite has not been determined, and the specific F f carbon is high (at 23650 deg. Fahr. it is 0.505) arying with rise in temperature; therefore, the ng point of the iron will be high and the latent f carbon in solution high. If an equal quantity of heat be given out (and it is) he graphite when the reverse change takes place— ng—then the carbon, as it separates out of solu- with the iron, must give up equally as high heat— the giving up of this latent heat by the carbon parates out through the different stages of cool- ngs fluidity of the metal and controls its point. Each time the metal temperature is ts power to hold carbon in solution decreases; e, as more carbon separates out, additional heat 'y its dissociation. ild seem that, in a measure, this is a rational ition as to why the melting point of gray iron than that of white iron; also why its fluidity nged over that of white iron by reason of the percentage of graphite present; and also why ezing point is lower than its melting point. The ide in iron is a very unstable compound, and rmed at a high temperature decomposes into and iron according to the formula: Fe,C — Later on, in discussing white iron, another enon of the performance of iron carbide will be | A typical gray iron melts at about 2260 to ; ‘0 deg. Fahr. (J ire iron-may be designated as a stable system Mottled Iron issification of mottled iron, with reference to ‘omposition, may be described as partly gray white iron; or the “hybrid” of cast iron— white nor gray iron. Its matrix contains f small size graphite and particles free from cementite and pearlite. In the classifica- ig iron it is graded as low silicon, 0.75 to 1.25 ind contains high sulphur, usually 0.08 to 0.12 It is generally the product of an irregularly irnace, tion of metal which lies between the chilled hub of a carwheel, or between the chilled ar i core of a chilled roll, is typical mottled the metal the larger the graphitic flakes will occur. It contains much free cementite, hence is inclined to be hard and brittle. A typical mottled iron melts at about 2200 to 2250 deg. Fahr. White Iron White iron is a supercooled solution of iron and carbon; and, compared with gray iron, may be con- sidered an unstable system between Fe,C and Fe. That is, its carbon is in an unstable condition, due to the iron carbide not having had an opportunity, during the rapid cooling process, to carry forward the reaction: Fe,C 3Fe + C. Thus, an iron suddenly cooled pre- sents the spectacle of having its constituent molecules frozen before there has been sufficient lapse of time for proper “molecular adjustment”—hence the molecules are tense and subject to crack by sudden impact or rapid heating and cooling. By annealing such an iron a sufficient length of time, there will be created a “molecular readjustment,” and high tension wil] thus be relieved. Molecular readjustment may be illustrated by refer- ence to the treatment of “fatigued” iron or steel. Thus, a chain or wire rope which has undergone severe strain of molecular structure may be materially strengthened by the application of heat to readjust its molecules and thereby relieve the tenseness. In the production of chilled carwheels it is very necessary that the wheels be placed in “soaking” or annealing pits, after having been removed from the molds at red heat, in order that there may be created a readjustment of the differ- entiating molecular structure of the three combined types of metal—white, mottled and gray—thus reliev- ing the tension and preventing cracks and weakness. During the quick-setting period of white iron the iron carbide has not had sufficient time to decompose into iron and carbon; therefore, after the solution of iron and carbon has set or frozen, this condition renders the carbon very susceptible to subsequent heat reac- tions. That carbon atoms are migratory, or move and are transferred, is fully demonstrated by the change of structure from white iron to malleable under intense heat; and by the fact that solid iron or steel will absorb carbon, upon being placed in contact with incandescent carbon. It is possible to produce a white iron in the presence of 2.00 to 3.00 per cent silicon, and in the absence of much manganese and sulphur, if the mixture be melted hot and cooled quickly before the iron carbide has had time to break up. This fact is demonstrated by easting iron in chilled molds, or cooling it quickly by a spray of water. It is also possible for an iron containing a small amount of silicon and large amounts of manga- nese and sulphur to cool slowly and yet be white in nature. This is illustrated by casting grinding slugs and stars in green sand molds. A typical white iron melts at about 2000 to 2070 deg. Fahr. Lack of reactions created by graphite separating out of solution, to prolong the fluidity of the metal, amet | blending f thi > is . ‘ . ; x nearer the all aa yd ane aos explains why the freezing and melting points of white ¢ é Ps : y : ea Oe oN eee iron may be considered practically the same. Hence i m, Ala. white and mottled iron will melt at a lower tempera- i i 585 i a epi 8 eR 8 Sop per OE ee. a ho eA SESE SIE $9 MLE ES LAPS OODLES i ences oe 586 THE IRON AGE ture than gray iron, and freeze at practically the same temperature. Skill of Manufacture—Gray Iron Compared with the high skill and art necessary in the production of chilled or hardened castings, there is usually as fine art and skill needed in the production of certain types of gray iron castings. The founder’s wit and skill should be at “par” when he decides to enter the field of brake shoe manufacture, engine and automobile cylinders, piston heads and rings, projec- tiles, shells, propeller blades, ingot molds, welding rods, acid and alkali resisting castings, glass molds, stills, eggs, retorts, valves, fittings, etc. The relative im- portance of standardizing certain of these castings is briefly touched in the following paragraphs: Brake shoes: A casting which will resist sudden and variable frictional wear, yet not be so hard as to break down in an irregular way the wearing tread of the wheel, should be the aim of the manufacturer of brake shoes. The silicon should be fairly low, sulphur low, phosphorus medium and manganese fairly high. The braking power of the shoe will be commensurate with its softness; but soft shoes wear more rapidly. One street railway system manufactures its own brake shoes; they are chilled throughout. This company is noted for the number of flat wheels on its ears; also for the “bell chimes” created by the shoes idling against the wheels while the car is in motion. The following analyses are recommended for brake shoes: Percentage Contents Total Si Ss P Mn Carbon Hard 1.50 0.08 0.60 0.70 3.25 Soft 2.00 0.07 0.70 0.50 3.40 These castings are sold under a guarantee, hence the percentage of good foundry iron should be used as the base metal, with major percentages of steel and low silicon cast scrap. Automobile castings: The manufacture of auto- mobile cylinders requires a standard of high art. The cylinder specifications not only require minimum thick- ness, but maximum strength and density, to insure safety from impact of explosion and effective compres- sion; also to care for contraction and expansion due to fluctuating temperatures. Minimum frictional wear is also essential. These are a combination of factors for solution by the most renowned construction engi- neers. The ingenuity of the molder is also put to a severe test, for much depends on the construction of the mold, and on the gating and pouring. Following are suggested analyses for cylinders: ; Total s s P Mn Carbon Medium ...1.75-1.85 0.07-0.08 0.25-0.35 0.75-0.80 3.30 Light .....2.00-2.15 0.06-0.07 0.25-0.35 0.60-0.70 3.40 Piston heads and rings should be of softer material, in order not to scorify or wear away the cylinder. The rings should be of a springy nature. Following com- positions are suggested: Total Rings: Si S > Mn Carbon Medium 2. 0.07 0.75 3.40 Light 2.25 0.06 5 0.65 3.45 Pistons: Medium 85 0.07 .25 0.60 3.40 2 0.06 35 0.50 3.45 Projectiles; shells: Cast projectiles, ordinarily used by the Government for target practice, require for their production strict attention to melting practice; also gating and molding. A dried mold, whirl gate and bottom pour are features which will tend to sound- ness and homogeneity of casting. Shells should be cast vertically, and may number four to the flask for smaller sizes. Twenty-five per cent of steel scrap may be used to good advantage in large size shells, and September 8, 1921 from 18 to 20 per cent in smaller sizes. Steel will lower the phosphorus and total carbon. As compressive strength, or resistance to expansion, is an important requisite of shell metal, density is a controlling factor. Specifications usually call for 28,000 to 30,000 lb. per sq. in. tensile strength, and 18-in. impact. Inasmuch as the smallest pin-hole may cause the rejection of shells, it is necessary to minimize oxidation of the metal and guard against segregation, by the use of low phosphorus metal superheated and poured hot. Charges should be well fluxed; good sub- stantial risers used, and metal be allowed to cool in the mold 4 to 6 hr. : Following analyses are suggested: Total : e Mn Carbon Light, 3 to 5 in ; , 0.30 0.60 3.35 Medium, 6 to 8 in.... 1. , 0.30 0.70 3.20 Heavy, 10 to 12 in... 1. ‘ 0.30 0.80 3.10 Propeller blades: Because propeller bladeg are for use in both fresh and salt water, corrosion at once sug- gests itself. Low total carbon, with comparatively high graphite, resists corrosion from salt water. The silicon should not be too high, manganese medium, phosphorus and sulphur reasonably low. As much as 20 per cent steel will assist in lowering total carbon. If propeller blades are heated, and then coated with tar, the treatment will assist in resisting corrosion for a long period of time. Following analyses are sug- gested: Total Ss - Mn Carbon * 0.06 0.40 0.50 3.40 Medium ‘ 0.08 0.40 0.60 3.25 0.10 0.40 0.70 3.15 Ingot molds: Service and economy are the prime requisites of ingot mold metal. The molds are bulky castings, but continued service depends on their com- position; more especially the economy question, as old and worn-out molds are put through the open-hearth furnace for entrance into a new steel mixture. There- fore sulphur and phosphorus should be low. One steel plant produces periodically, for this purpose, in one of its small blast furnaces, a metal of the following analysis: silicon 1.80 per cent, sulphur 0.04 per cent, phosphorus 0.08 per cent and manganese 0.80 per cent. This metal is produced from steel scrap, manganous slag and silica rock. It is then put through the cupola, and poured as ingot molds of following analysis: Total Si Ss P Mn Carbon 1.65 0.06 0.10 0.65 3.40 This analysis constitutes an excellent ingot mold metal, and its duplication in a cupola is suggested. Welding rods: Clean and flawless metal with reasonably high melting and freezing qualities are de- sired in welding rods. High silicon, with its fluxing qualities, is a desiratle element. Sulphur and phos- phorus should be reasonably low and manganese medium. Following composition is suggested: Total i Ss P Mn Carbon 3.50 0.06 0.50 0.50 3.50 Snap graphite board flasks, inclined vertically, make desirable molds for casting rods. The product will be clean and symmetrically shaped. However, the rods may be successfully cast in dry or green sand. Because the metal section is small and the iron poured hot the grain will be close and even. Acid-resisting Castings.—Of course, the ideal metal to resist corrosive effects of hot and cold acids would be one which approaches iron silicide; that is: an alloy metal which contains 12 to 15 per cent silicon, or fol- lowing approximate analysis: Total Si s P Mn Carbon. 14.00-15.00 0.05 0.05-0.20 0.35-2.50 0.60-1.25 September 8, 1921 Such a metal, however, could not be classed as cast ‘yon. This metal may be produced in an air furnace electric furnace by the use of ferroalloys. The earest approach to an acid-resisting metal, poured from cupola iron, would be of following suggested omposition: Total Si s P Mn Carbon ~ Ee Pee 2.00 0.05 max. 0.30 max. 0.75 3.25 Viedium ... 1.50 0.05 max. 0.30 max. 1.00 3.20 Heavy .... 1.25 0.05 max. 0.30 max. 1.25 3.10 Alkali and heat resistant castings come under the above analyses, with slight rise in silicon and lowering of manganese for heat resistant castings; and _ still further reduction of manganese for alkali resistant castings. Gun Iron—As the name implies, this metal once found its most practical use in ordnance work, mortar runs, cast iron cannon, etc. It has since gained quite a reputation for use in chilled rolls, gas and steam en- vine cylinders, piston rings, liners and various engine astings which require a smooth, dense and tough structure—“Hunt-Spiller” metal being a fair specimen. This metal is also essentially a product of the air vr electric furnace, in which the elements may be regu- lated to suit the specific casting required. Carbon con- trol is ideal under such melting conditions, as well as silicon, sulphur, phosphorus and manganese, according to the lining used. While large percentages of steel may be used in cupola mixtures, yet the total carbon in resultant casting may vary considerably, due to the metal’s contact with incandescent carbon. Additions of steel scrap will materially assist in accomplishing the desired results. The nearest approach to the analysis of gun iron metal in cupola mixtures would be the following: : Total Si Ss P Mn Carbon Light i ceeeue ue 0.05 0.35 0.60 3.35 Medium se aoe 0.06 0.35 0.70 3.20 Heavy 1.15 0.08 0.35 0.80 3.00 Skill of Manufacture—White Iron There is no branch of foundry work where skill of operation and metallurgical knowledge are put to a more thorough test than in the manufacture of chilled or hardened castings. The real fine point to be ob- served in the production of hardened castings is the manner in which the transition of the white section is made to interlock or merge into the mottled section. It should be the endeavor of the producer to have the white fibers interlock or “dove-tail” into the matrix of the mottled section. This conditions decreases straight line cleavage areas and minimizes cracks. Manganese promotes a, fibrous, tough chill, whereas sulphur is more conducive to cleavages and brittleness. High phosphorus also has a tendency to produce cleav- ages, as well as, segregation. ‘or many years foundrymen clung tenaciously to idea that it was absolutely essential to use charcoal mixtures requiring a hardened or chill process. ‘e modern foundry practice has to a great extent “amoved the barrier, the fact remains that dependable v silicon iron of high grade is yet peculiarly a prod- t the charcoal furnace. low silicon irons, 1.25 per cent and under, pro- n a coke furnace, are likely to be “off grade” by of excessive sulphur or other causes incident rregularly working farnace, they may prove to nferior product. In many instances, however, ssible to use the higher silicon coke irons, 2.25 _per cent silicon, in chilled or hardened mix- by having available sufficient low silicon cast ¥.00 to 0.70 per cent silicon, and steel scrap. Wi , \ THE IRON AGE 587 The following comparative results reported by Evans are interesting: Mixture A Per Cent Analysis Per Cent Pig iron 11.6 Silicon 0.607 Steel scrap 8.3 Sulphur 0.148 Old wheels 80.1 Phosphorus 0.430 Ferromanganese 0.2 Manganese 0.563 Graphite carbon 2.587 Combined carbon 0.729 Total carbon 3.316 Tests Crack Break Chill Average drop blow ........ 27.6 66.2 0.51-0.60 in Chilled Tread Test Ingot SERGE = |. vs aciceteebacedsuben<< 477 482 Load Deflection Transverse 1%-in. round-gray......... 2.948 Ib. 0.123 in. Transverse 1% in. square-chilled...... 2,611 Ib. 6.043 in. Mixture B Per Cent Analysis: Per Cent Charcoal pig 13.30 Si 0.634 Steel scrap 8.30 Ss 0.160 Old wheels 78.30 P 0.350 Ferro-manganese 0.05 Mn 0.425 Graphitic carbon 3.191 Combined carbon 0.344 Total carbon ol 3,535 Tests ' 7 Crack Sreak Chill Average drop blow......... 15.4 49.6 0.46-0.58.in, Chilled Tread Test Ingot PN gna cease ds cheb cane Troe 57 478 Load Deflection Transverse 14 in. round-gray......... 2,975 Ib. ®.111 in. Transverse 14% in. square-chilled....... 2,617 1b 0.043 in. Car Wheels.—An economical mixture, as well, as one which will produce a wheel to stand all the require- ments of the Master Car Builders’ Association, may be made with the following materials: Total Si Ss P Mn Carbon 12.0 per cent pig..... 2.30 0.04 0.55 1.15 10.0 per cent steel.... 0.10 0.03 0.06 0.50 78.0 per cent wheels... 0.65 0.12 0.35 0.58 0.3 per cent ferro- manganese ....... — dunce «ai 80.00 oe Wheel analysis...... 0.65 0.12 0.35 0.60 3.35 The depth of chill on tread of railroad carwheel ranges from % to % in.; street carwheels require con- siderably lower depth of chill. The safer policy would be to aim for a lower silicon content in a wheel, rather than a high one, for high-silicon iron or ferrosilicon may be quickly added to raise the silicon, whereas if the silicon should be too high, more drastic steps have to be taken to “pig down.” Therefore, in mixtures for chilled castings, the silicon content in the metal mix should be low. Chilled Castings.—Where only a hard, smooth chill is wanted, the manganese may range from 0.25 to 0.35 per cent; sulphur 0.07 to 0.10 per cent. This especially applies to chilled rolls. Following approximate analy- ses have proved good mixtures for rolls: Total Si S P Mn Carbon ER Pero ae 0.85 0.07 0.50 0.35 3.00 ee 0.60 0.08 0.35 0.35 2.85 Following analyses for other chilled or hardened castings have proved satisfactory: Total Si Ss - Mn Carbon Piet. pelmte-.6 ves coe 1.25 0.07 0.50 0.85 3.10 EE. -tecapabices 0.85 0.08 0.40 0.50 3.00 Anvil blocks ........ 0.85 0.10 0.35 0.60 3.00 re aie . 0.70 0.08 0.40 1.00 3.00 Grinding balls . 0.75 0.15 0.40 0.80 3.00 Rate of cooling also has its effect on the chill and texture composition of metal mixtures desired for hard- ened castings. The process is accomplished by. the sudden cooling of the molten metal coming in contact with a metal chiller, the depth of chill depending on the chemical composition of the metal and the tempera- ture at which it is poured. Chill test blocks are made 6 x 4 x 1% in., and are usually cast in the mold with the casting, and from the same ladle of metal, as a check or indication of chilling qualities. Low silicon, high combined carbon and medium manganese are ideal chemical components, and hot un- oxidized metal, poured at a temperature between 2400 and 2500 deg. Fahr., favors satisfactory chilling con- ditions. If melting conditions should be right, and careful attention given to the matter of pouring tem- nat oe “ee mah a a. ee em tes are oa! Me tent M - os Selinemen temitaieeita - h Fie : ve ae ; wy 588 THE IRON AGE perature, higher silicon mixtures may be made to pro- duce a deep chill. However, the metal must not be oxidized, or the resultant casting will be irregular and weak. Iron properly chilled should show a structural mix- ture of cementite and pearlite, with quite an excess of free cementite; the mottled portion, in addition to cementite and pearlite, will reveal small patches of graphite; the gray portion will show relatively large CHINA BUYS LOCOMOTIVES American Builders Secure Part of Large Order for Rolling Stock WASHINGTON, Sept. 5.—Forty-one locomotives were required for three Chinese Government railroads, for which bids were received from 28 manufacturers, in- cluding British, German, French, Belgian, Japanese and American factories. The business was divided into four items and awarded as follows: Item 1.—30 Prairie type locomotives for Pekin-Han- kow Railway. Awarded to Forges Usines et Fonderies de Haine-St. Pierre Ateliers Metallurgiques Tubize So- ciété Franco-Belge a la Croyere, Belgium. Item 2.—6 English type locomotives for Shanghai- Hangchow-Ningpu Railway. Awarded to Forges Usines et Fonderies de Haine-St. Pierre Ateliers Metallur- giques Tubize Société Franco-Belge 4 la Croyere, Bel- gium. Item 3.—2 Mikado type locomotives for Pekin-Sui- yuan Railway. Awarded to American Locomotive Co. Item 4.—3 Pacific type locomotives for Pekin-Sui- yuan Railway. Awarded to American Locomotive Co. Two hundred and forty all-steel cars were required, 100 of which were open and the others covered. Al- though three items were represented, all were awarded to Compagnie Centrale de Construction A Haine-St. Pierre, a Belgian company. Bids were submitted in seven different currencies, and certain bids were rejected because the delivery of- fered was not as specified. The following table gives the lowest bid of each of the several nationalities: Equiva- ———— —-Bid-- ——~ lent if Currency Amount Taels Thirty Prairie type locomotives: Belgium Belgian franes., 452,550 55,210 Japan Yen 85,000 62,475 United States 42,200 68,510 Germany 49,215 76,280 Great Britain Pounds sterling 13,647 78,880 Six British type locomotives : Belgium Belgian francs. 434,66 53,025 United States seccec es EEO 3,23 67,000 Great Britain Pounds ak 67,915 Germany ..Dollars 9,5 76,790 Three Pacific type locomotives : Japan Yen 94,000 51,740 Belgium ...............Belgian franes. 515,000 52,830 United States Dollars ....... 50,880 78,860 Great Britain Pounds sterling 14,310 f Germany is)» sn bs Re 53,910 Two Mikado type locomotives: Belgium Sie ea . Belgian 548,600 66,930 Japan Yen 100,000 73,500 United States ... 52.000 80,600 Great Britain Pounds 14,904 86,150 Germany ..Dollars 57,000 88,350 One hundred all-steel “open wagons” : Germany Pounds sterling 512 3,540 Belgium ... .. Belgian . - 31,325 3.820 United States Dollars 3,950 Japan Yen ean 6.000 4,410 Great Britain Pounds sterling 1,016 5,870 Items and Nationalities .710 560 2 8, 2 3, It will be noted that the relative positions of the various countries change very little and that the Amer- ican product is competitive. Belgium and Japan were consistently lower, and Great Britain and Germany con- sistently higher, in prices for locomotives, than was the United States. It is necessary to make certain allow- ances in interpreting the above data. Specifications for the 30 Prairie type locomotives conformed almost ex- actly with the Belgian locomotive already operating, and the 6 British type locomotives are to conform strictly with existing locomotives of British manufac- ture. Certain bids were disqualified, even though nom- inally lowest, because they did not include all items as required for delivery as specified. The two Mikado and September 8, 192) plates of graphite in pearlite, with a comparatively small amount of free ferrite in pearlite. The chemica! composition of white, mottled and gray sections of hardened iron would be expeeted to approximate the following percentages: Graphitic Combined Tota! Si Mn Carbon Carbon Carbor 4 White.... 0.65 ‘i 0.40 0.50 0.05 3.25 3.30 Mottled... 0.65 12 0.39 0.52 1.50 1.60 3.10 a 0.60 ; 0.38 0.55 2.40 0.80 3 2 vu three Pacific type locomotives were awarded to th lowest bidder that conformed to the specifications fo: a cast-steel bar frame. These figures indicate what is to be anticipated in the present disturbed condition of international ex- change. In spite of the fact that the American dollar is at a premium over all the other currencies, it is sti)! possible to submit competitive prices. As the indica- tions are that the amount of this premium will grad- ually decrease during the next few years, it should have the effect of placing American manufacturers in an in- creasingly favorable position. If the Belgian franc stood at 10c. instead of &c. it would have raised all of the Belgian bids 25 per cent. Also it is understood that a great deal of the steel now being made in Belgium is produced largely from scrap, rather than being worked up from ore, and is corre- spondingly cheap. As time exhausts these stocks it wil! probably be found that Belgian prices increase. It is noteworthy that the German bids on locomotives were in dollars; on cars, in pounds sterling. Steel Corporation Analysis Methods The various committees of chemists of the United States Steel Corporation have prepared up-to-date pamphlets covering the following subjects: “Sampling and Analysis of Iron Ores,” “Sampling and Analysis of Pig Iron,” “Sampling and Analysis of Fluxes, Cinders and Refractories,” “Sampling and Analysis of Plain Steels,” “Sampling and Analysis of Ferroalloys and Bearing Metals,’ “Sampling and Analysis of Gases,” and “Sampling and Analysis of Coal, Coke and By- products.” These pamphlets, it is announced, are pre- pared solely for the use of the chemists of the Stee! Corporation and are of interest only to chemists. To limit the requests from outside sources, which the com- mittee does not feel it can wholly deny, a charge on them of $1 each has been imposed, payable to the Car- negie Steel Co., payment to accompany the request. The matter is in charge of J. M. Camp, chairman Chem- ists’ Committee, U. S. Steel Corporation, Carnegie Building, Pittsburgh. The evening courses of Pratt Institute, Brooklyn, N. Y., begin Sept. 22 for the trade classes and Sept. 26 for the technical classes. The technical courses !n- clude industrial electricity, practical electricity, tech- nical chemistry, mechanical drawing and machine de- sign, elements of power plant operation, stationary steam plant operation and automotive engine mainte- nance and repair. The trade courses include machine work, pattern making, foundry practice, forging and heat treatment and machine shop foremanship. The President of the Argentine Republic has sanc- tioned a decree authorizing a further increase of 4,000, 000 pesos in the budget for sanitary works for the city of Buenos Aires during the current year. The money will be used in extending the radius of the water and sewer systems and will call for the purchase of p'pe and fittings. The work is under the direction of Di- rector de Obras Sanitarias de la Nacion, Buenos Aires. ———————————— Following an announcement by the Aetna Nut Co., Southington, Conn., last week of a reduction in wages of 15 to 25 per cent, about 10 per cent of the e™- ployees, mostly roughers on heavy and light ro''s, walked out, and the plant was obliged to suspend 0P- erations. The plant had resumed last week follow- ing a long period of ‘nactivity. British View of American Steel Making Blast Furnace and Open-Hearth Practice Compared—Coke-Oven Gas as a Fuel— Rolling Mills Steel Institute publishes an article, “Snapshots of an American Pilgrimage’ by R. Percival ith, which was read at the June meeting of the ‘ety. The author is connected with the Lanarkshire Steel Co., Ltd., Motherwell, Scotland. His impressions ere