| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent longitudinal crack from occurring on a casting piece surface when hypo-peritectic steel having an Al concentration of 0.1 to 2.0 mass% is continuously cast.SOLUTION: Mold flux includes CaO, SiO, oxide of alkaline metal and fluorine compound as essential components. When mass concentration (mass%) of Al contained in molten steel is presented as A, an initial composition of the mold flux before being supplied into a casting mold satisfies relations: 0.9 -0.35×A≤f(1)=(CaO)/(SiO)≤1.9-0.35×A, 0.05≤f(2)=(CaF)/{(CaO)+(SiO)+(CaF)}≤0.40, 0<f(3)={(fluoride of alkaline metal)+(AlO)}/{(CaO)+(SiO)+(fluoride of alkaline metal)+(AlO)}≤0.40 and, on the other hand, the composition of the mold flux after being supplied into the casting mold during continuous casting and being reacted with the molten steel in the casting mold satisfies the relations: 1.10≤f(1)≤1.90, 0.05≤f(2)≤0.40, 0.10≤f(3)≤0.40. By supplying the mold flux, Al-containing steel is continuously cast such that the mold flux maintains a crystalline phase in a film formed in the casting mold.</p> |
