| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an ingot of extra-low carbon steel by which production of the ingot of the extra-low carbon steel having≤100ppm carbon concentration and≤2ppm oxygen concentration can be stably effected. SOLUTION: The ingot of the extra-low carbon steel having≤100ppm carbon concentration is produced by tapping off undeoxidized molten steel primarily refined in a converter and performing a secondary refining using a vacuum-degassing apparatus, wherein first in the vacuum-degassing apparatus, the oxygen concentration in the molten steel is measured, according to this measured value, high carbon ferro-manganese as the deoxidizing agent is added to the molten steel, the oxygen concentration in the molten steel is preliminarily adjusted to 400-500ppm, then the decarburization is performed, and thereafter, a finish-deoxidation is performed using another deoxidizing agent to obtain≤2ppm oxygen concentration. COPYRIGHT: (C)2009,JPO&INPIT
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