| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently melting a low carbon aluminum-killed steel at a low cost in comparison with a case of using only the conventional primary refining furnace, by combining the primary refining with a converter and a secondary refining with a vacuum-degassing apparatus under the optimum condition. SOLUTION: When the low carbon aluminum-killed steel having 0.02-0.06 mass% carbon concentration, by which the decarburize-refining is applied to molten iron under atmospheric pressure by using the converter and successively, the molten steel obtained with the decarburize-refining, is decarburize-refined under reduced pressure in the vacuum-degassing apparatus; in the converter, the decarburize-refining is applied until the carbon concentration in the molten steel becomes 0.07-0.12 mass%, and after completing the decarburize-refining, this molten steel is carried into the vacuum-degassing apparatus under state of performing no-deoxidation to the molten steel with Al and then; in the vacuum-degassing apparatus, the vacuum-degassing refining is applied until the carbon concentration becomes 0.02-0.06 mass% by blowing oxygen gas into the molten steel under atmosphere at lower than the atmospheric pressure and thereafter, the deoxidation is performed by adding Al into the molten steel to melt the low carbon aluminum-killed steel. COPYRIGHT: (C)2006,JPO&NCIPI
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