| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a molten steel, which controls a loss of valuable components such as iron or manganese caused by dissolution into slag in a refining step in a converter, and reduces the oxidation loss of a deoxidizer and an alloy agent which are added in subsequent steps. SOLUTION: In the method for manufacturing the molten steel by preliminarily removing phosphorus in a molten pig iron tapped out from a blast furnace and decarbonization-refining it in a converter 1, this manufacturing method comprises: lowering a phosphorus concentration in the molten pig iron to the level of a steel product in the above preliminary phosphorus removal treatment; refining it with an amount of slag of 20 kg or less per ton of treated molten pig iron, in the decarbonization refining step in the converter; and reducing the slag 6 by adding a slag-making material 7 comprising one or more materials of a CaO source, charcoal wood and a deoxidizer, in the latter part of the decarbonization refining step, to control an oxygen concentration in the molten steel in the end of the decarbonization refining step to 300 ppm or less. COPYRIGHT: (C)2004,JPO
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