Girod estimated the cost of producing steel from molten steel at the same plant as follows:

Cost of refining steel from molten charge in Girod furnace at Ugine.

The estimates of Girod do not include expense for ingots, molds, superintendence, laboratory, amortization, general charges, or royalty charge. These figures apply only to conditions such as prevail at Ugine, where power is very cheap and the cost of material is high.

COST OF PRODUCING STEEL IN THE GRÖNWALL FURNACE, SHEFFIELD, ENGLAND.

The Electro-Metals Co., owners of the Grönwall patents, estimated the cost of production in 1912 for a 2-ton Grönwall furnace operating at Sheffield, England, as follows:

Cost of refining steel from molten charge, Grönwall furnace.

The items of labor, amortization, interest, raw materials, and general charges are omitted from the estimate given above. The figures refer to the production of steel with a sulphur and a phosphorus content below 0.02 per cent.

COST OF PRODUCING STEEL IN RÖCHLING-RODENHAUSER FURNACES.

a

Kjellin in 1909 estimated the cost of production of high-grade steel for castings at Volklingen, Germany. The cost under German

a

Kjellin, F. A., Induction and combination furnaces: Trans. Am. Electrochem. Soc., vol. 15, 1909, p. 172.

conditions with a 7-ton, three-phase Röchling-Rodenhauser furnace, using fluid basic Bessemer steel made at Volklingen, is estimated by Kjellin as follows:

a

Cost of producing steel for castings in a 3-phase Röchling-Rodenhauser furnace, from molten metal.

300 kilowatt-hours per ton at 2.17 cents per kilowatt-hour..

6.52

.425

.082

2,000 kilowatt-hours at 2.17 cents for 160 tons...

Refining:

Wages..

Materials:

Mill scale, 20 kg.

Lime, 30 kg..

Ferrosilicon, 6.5 kg.

Ferromanganese, 4 kg.

Power for cooling arrangements..

Repairs.....

Total..

087

.485

.214

196

. 194

8.822

To this must be added interest and the depreciation of the plant. Assuming 5 per cent interest and 10 per cent depreciation on $13,380, the approximate cost of the plant, gives $2,000 per year, which for 300 working days would give 41.2 cents per ton, so that the conversion of the fluid product from the basic converter into steel that can replace crucible steel for steel castings will cost $9.23 per ton exclusive of the cost of the molten steel charged. This cost is figured on a basis of three men operating the furnace.

Cost of producing rail steel in a 3-phase Röchling-Rodenhauser furnace, from fluid steel.

This estimate includes all items. If the cost of molten steel be disregarded, the refining cost, with power at 0.58 cent per kilowatt-hour, will be $3.08 per ton.

a Loc. cit.

The cost of making casting steel of the composition given on page 105, from cold scrap in the Röchling-Rodenhauser furnace, at Lansdown, Pa., is estimated by the Crucible Steel Casting Co.," as follows:

Cost of producing steel from cold scrap in the Röchling-Rodenhauser Furnace at Lansdowne, Pa.

Power, 844 kilowatt-hours at 0.7 cent per kilowatt-hour...

5.91

1.50

Interest, 5 per cent; depreciation, 10 per cent per ton..

Cost of 1 gross ton (2,240 pounds) electric steel ready to pour..

PROPERTIES OF ELECTRIC-FURNACE STEEL.

25.39

For many years all high-grade steels were manufactured by the crucible process, but since the advent of the electric furnace there has been a gradual adoption of that furnace for refining steel. For the complete refining of the highest grades of steel the use of the electric furnace is now thoroughly established in Europe. Any product that can be made by the crucible process can be made by the electric furnace, and in most cases with cheaper raw materials and at a lower cost. In the electric furnace complex alloy steels can be made with precision. The high temperatures attainable facilitate the reactions and alloys need not be used so largely for the purpose of removing gas. Very low carbon steels can be kept fluid at the high temperatures. Steels free from impurities and of great value for electrical apparatus can be made. With the electric furnace large castings can be made from one furnace, whereas in the crucible process steel from several crucibles must be used. For small castings, which require a very high grade metal free from slags and oxides, electrically refined steel is especially adapted. The electric furnace gives a metal of low or high carbon content as desired, hot enough to pour into thin molds and still free from slags and gases.

There is now a tendency among consumers of rail and structural steel to require a higher-grade steel at an increased price rather than steel of acid Bessemer or even of basic open-hearth grade at a lower price. With the high cost of power that now prevails throughout the steel centers of the United States the electric furnace can not

a Von Baur, C. H., "The Röchling-Rodenhauser furnace of the Crucible Steel Casting Co., Lansdowne, Pa.: Metall. Chem. Eng., vol. 11, 1913, p. 113.

compete profitably with either the acid Bessemer or the basic openhearth process in manufacturing steel of like grade from pig iron. It is in combination with either of these processes that the electric furnace seems destined to be prominent in steel manufacture. The cost of superrefining in the electric furnace the molten steel from either of these processes, exclusive of the cost of the molten steel, varies from $1.50 to $2.25 per ton, depending on the cost of power and the impurities to be removed.

Experiments conducted by the United States Steel Corporation during the past four years show that, as compared with the acid. Bessemer and basic open-hearth processes, the electric process has the following advantages: A more complete removal of oxygen; the absence of oxides caused by the addition of silicon, manganese, etc.; the production of steel ingots of 8 tons weight and smaller that are practically free from segregation; reduction of the sulphur content to 0.005 per cent if desired; reduction of the phosphorus content to 0.005 per cent, as in the basic open-hearth process, but with complete removal of oxygen.

Acid Bessemer steel has been refined in the basic electric furnace, yielding steel of the following composition: Carbon, 0.55 per cent; manganese, 0.137 per cent; silicon, 0.13 per cent; sulphur, 0.017 per cent; and phosphorus, 0.022 per cent. Rails made from this steel are comparatively soft, but show less wear than Bessemer rails in the same track and subjected to the same service. About 5,600 tons of standard electric steel rails from electric-furnace steel have been in service in the United States for the past two years. These rails have been subjected to all sorts of weather and to temperatures as low as -52° F. It seems that rails made by the basic electric process can be made softer than by either the acid Bessemer or basic openhearth processes and yet show highly satisfactory wearing qualities.

No steel rails made by the basic electric process in service in this country have yet broken. Electric-furnace steel of a given tensile strength has a slightly greater elongation than basic open-hearth steel and is somewhat denser than basic open-hearth or acid Bessemer steel.

Below are given the averages of some comparative tests of rails from steel made in a Röchling-Rodenhauser furnace and Bessemer rails. The tests were made at Volklingen, Germany, for the Prussian State Railway.

a

Clark, E. B., Various types and applications of electric steel furnaces: Metall. Chem. Eng., vol. 10, 1912, p. 373.

16282°-Bull. 67-14- -9

Comparison of steel rails made in Röchling-Rodenhauser furnace with basic Bessemer steel rails.

The results of some comparative tests, made at South Chicago, of electric-furnace steel for plates and basic open-hearth steel for plates were as follows:

Average ultimate strength and elongation of electric and open-hearth plate

a Osborne, G. C., The 15-ton Héroult furnace at the South Chicago works of the Illinois Steel Co.: Trans. Am. Electrochem. Soc., vol. 19, 1911, p. 221.

The results show a 15.5 per cent increase in ultimate strength and 11.3 per cent decrease in elongation for electric steel, as compared with open-hearth plate steel of approximately the same chemical composition.

ACKNOWLEDGMENTS.

The author acknowledges information and assistance received from the following persons: W. S. Gifford, Colin C. Gow, and H. V. Clement, of London, England; A. Barry Aulton, J. L. Dixon, S. S. Parker, and R. A. MacGregor, of Sheffield, England; D. Wilkinson, of Braintree, England; M. Arnould, of La Praz, France; G. Komswowski, of Ugine, France; C. Hering, of Philadelphia, Pa., and others.