| 摘要 |
PURPOSE: A control method of slag for refining grain-oriented magnetic steel sheet is provided to minimize adhesion of slag to submerged pipe during degassing by injecting calcium oxide into slag when tapping molten steel of converter and injecting a small quantity of silica when bubbling molten steel, thereby making slag having low Al2O3. CONSTITUTION: In a method for tapping molten steel(5) for grain-oriented electrical steel sheet of high silicon steel from converter to ladle(3), bubbling molten steel received in the ladle and degassing molten steel using a degassing unit(1), the refining method of high silicon steel for preventing slag from adhering onto the inside of submerged pipe(2) of vacuum degassing apparatus comprises a step of injecting 2.5 to 5.5 kg/ton-steel of CaO into the ladle according to terminal point oxygen amount of the converter while molten steel of the converter is being tapped into the ladle; and a step of injecting 1.0 to 1.5 kg/ton-steel of silica into the ladle as strongly bubbling molten steel inside the ladle for 8 to 12 minutes using nitrogen, wherein 2.5 to 3.5 kg/ton-steel of the CaO is injected in case that the terminal point oxygen amount of the converter is 750 ppm or less, 3.6 to 4.5 kg/ton-steel of the CaO is injected in case that the terminal point oxygen amount of the converter is 751 to 900 ppm, and 4.6 to 5.5 kg/ton-steel of the CaO is injected in case that the terminal point oxygen amount of the converter is 901 ppm or more, and wherein injection of the silica is completed within 2 minutes after starting the strong bubbling.
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