TUNGSTEN STEELS MADE DIRECTLY FROM ORES

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  • タングステン鉱石を用ひて直接タングステン鋼を熔製せる工業実験報告

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By comparison of the formation heats of metallic oxides per kilogram, an interesting and unexpected fact was found that tungsten oxides (WO2 as well as WO3) are more reducible than the oxides of iron or manganese. The reducing power of the electric final slag is so strong that it reduces FeO or MnO in the metal completely. It was thought that it is possible to gain a refined tungsten steel by adding wolframite (61%WO3) on to the bare bath and reducing two hours more with sufficient coke (18% by weigh ) under normal reducing slag. <BR>Being based on the abovementioned ideas, 35 times preliminary tests were conducted, and 1.82.4% W steels were melted 10 times in succession with the same 5-ton Héroult furnace of the Honkeiko Special Steel Co., Ltd. The excellent result was summarized as follows: <BR>(1) The mean yield of tungsten amounted to 99.6% (nearly all tungsten was reduced) and there remained only traces in the slag. <BR>(2) All results of the mechanical test surpassed those of their specifications. In case the reducing is preferably 30 minutes longer, the more manganese reduced and the higher tensile strength obtained. <BR>(3) The present direct method of manufacture is more economical and less labourous than the ordinary FeW process. Following the aforementioned researches, the Honkeiko Special Steel Co., Ltd. made success in melting low-alloy tungsten steels with less than 24% W by the present method. <BR>Again, recently the author found by the log sheets a distinct difference in the reduction speeds between Mn and W. At present, the author is expecting future possibilities in the following three lines: <BR>(1) Higher-alloy tungsten steels to be obtained by reducing wolframite. for 6070 minutes and refinig them with a new second slag which contains no ore. ("3 slags process") <BR>(2) Further higher-alloy tungsten steels (high speed steels) to be obtained from the WO3 manufactured by treating the wolframite hydrometallurgically. <BR>(3) Alloy steels with Mo, Ni, Co, Cu, Cr or Mn to be obtained by the same principle.

Journal

  • Tetsu-to-Hagane

    Tetsu-to-Hagane 29 (2), 141-152, 1943

    The Iron and Steel Institute of Japan

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