| 摘要 |
PURPOSE: A method for desulfurizing molten steel for use in the manufacture of low carbon steel sheet for shadow mask is provided to produce an extremely low carbon low sulfur steel sheet with a sulfur content of less than 80 ppm and a carbon content of less than 100 ppm is provided. CONSTITUTION: In a manufacture method of extremely low carbon steel with a sulfur content of less than 80 ppm and a carbon content of less than 100 ppm in which after preliminary desulfurization below 120 ppm of sulfur content, hot metal is decarburized in converter so that carbon content of the hot metal is reduced below 500 ppm, and then the molten steel is tapped into ladle for secondary refining, followed by bubbling and vacuum degassing, the method is characterized in that calcium oxide is poured into ladle in an amount of 4.6 to 7.8 kg/ton·molten steel during tapping; Al2O3-based flux is poured to slag layer in an amount of 1.25 to 2.25 kg during secondary refining; the molten steel is agitated for more than 2 minutes during bubbling; and Al2O3-based flux comprises 50 to 70 wt.% of Al2O3, 10 to 30 wt.% of CaO, 10 wt.% or less of SiO2, 12 wt.% or less of other components including P2O5, S, FeO and MgO.
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