| 摘要 |
PURPOSE: A method for deoxidizing molten steel is provided which not only deoxidizes molten steel more economically, but also minimizes formation of aluminum oxide inclusions in molten steel in the degassing process by using ferrosilicon and aluminum as deoxidizer when deoxidizing molten steel in the degassing process. CONSTITUTION: In a method for deoxidizing molten steel by injecting deoxidizer into molten steel after completing decarburizing operation in steelmaking degassing process for manufacturing ultra-low carbon steel, the method comprises a step of injecting 0.15 to 0.25 kg/molten steel-ton of ferrosilicon (Fe-Si) into molten steel if concentration of dissolved oxygen before deoxidation after decarburization in the steelmaking degassing process is 300 ppm or les; a step of first deoxidizing molten steel for 2 to 3 minutes by injecting 0.25 to 0.35 kg/molten steel-ton of ferrosilicon into molten steel if concentration of dissolved oxygen before deoxidation is 300 ppm or more; and a step of finally deoxidizing molten steel by secondly injecting aluminum into molten steel, wherein temperature of molten steel to be treated in the steelmaking degassing process is 1,590 to 1,615 deg.C, and content of carbon in molten steel manufactured in the degassing process is 70 ppm or less.
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