| 摘要 |
PROBLEM TO BE SOLVED: To provide a desulfurizing method with which the desulfurization is performed at remarkably high efficiency in comparison with the conventional method by optimizing the composition of slag and molten steel in a ladle and the order of refining in a vacuum-degassing facility, when the molten steel is desulfurized with the vacuum-degassing facility. SOLUTION: In the desulfurizing method for the molten steel, a silicon-containing ferro-alloy is charged during tapping the molten steel into a ladle from a decarburize-refining furnace for performing the decarburize-refining under the atmosphere and the silicon concentration in the molten steel 3 in the ladle, is adjusted to≥0.10 mass%. A modifier for slag, containing aluminum, is added into the slag 4 in the ladle after tapping the molten steel to adjust the total concentration of the total Fe and manganese oxide in the above slag to≤5 mass%. Thereafter, the ladle is carried to the vacuum-degassing facility 1 and desulfurizing agent together with gas for carrier, are injected and added toward the surface of the molten steel under reduced pressure refined with the vacuum-degassing facility through a top-blowing lance 13, to perform the desulfurizing treatment to the molten steel. COPYRIGHT: (C)2008,JPO&INPIT
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