| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a manganese-containing extremely low carbon steel, which achieves high cleanliness and conducts efficient smelting, even if a Mn content is comparatively high. SOLUTION: When smelting the extremely low carbon steel containing 0.3-3 mass% Mn by decarburizing the molten steel tapped out from a converter, in a vacuum degassing tank, this method comprises controlling the Mn concentration in the molten steel before the above decarburization treatment to 0.3 mass% or less, decarburizing it, deoxidizing it, and adding metallic Mn while keeping a pressure in the above vacuum degassing tank to 1,330-6,670 Pa, to adjust the Mn concentration in the molten steel to be a desired value. In the above method, preferably, a reducing agent is sprayed to a floating slag on the molten steel in a ladle, before the above decarburization treatment; metallic oxides contained in the slag are reduced; or an RH process is adopted for the above vacuum degassing tank. COPYRIGHT: (C)2003,JPO
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