| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a desulfurizing method which reduces a usage of CaF<SB>2</SB>, can desulfurize even with a ladle slag containing a low concentration of CaO, and further can accelerate desulfurization in an arbitrary concentration of CaO. <P>SOLUTION: In a desulfurization treatment of spraying or blowing a flux on or into a molten steel in a decompressed vacuum chamber with the use of a vacuum degassing device comprising a dipping tube and a vacuum chamber, this desulfurizing method employs a flux consisting of a mixture of CaO with a metallic Ca or a Ca alloy, wherein a blended ratio W of pure Ca in the flux satisfies the expressions: CaO/Al<SB>2</SB>O<SB>3</SB><0.75: 10>W>5.2%, CaO/Al<SB>2</SB>O<SB>3</SB>>1.55: 10>W>0.08%, and 0.75≤CaO/Al<SB>2</SB>O<SB>3</SB>≤1.55: -6.4×(CaO/Al<SB>2</SB>O<SB>3</SB>)+10≤W≤10, wherein CaO/Al<SB>2</SB>O<SB>3</SB>is a mass ratio of CaO to Al<SB>2</SB>O<SB>3</SB>in the ladle slag before starting the treatment; and W is a blended ratio (mass%) of the pure Ca in the flux. <P>COPYRIGHT: (C)2004,JPO</p> |
