| 摘要 |
PROBLEM TO BE SOLVED: To provide an ingot formation method of a high-S, low-N steel alloy which forms ingot of a steel alloy high in S concentration and low in N concentration by using LF.SOLUTION: An ingot formation method includes a heat-raising desulfurization step (S14) of subjecting molten steel after Si- or Al-killed molten steel tapping from a converter in LF to desulfurize the molten steel to a concentration of S in the molten steel of 0.006 mass% or lower, a denitrification step (S18) of denitrifying the molten steel during a vacuum refining period by a vacuum refining installation after the heat-raising desulfurization step (S14) and a sulfur addition step (S22) of adding S to the molten steel during the vacuum refining period by the vacuum refining installation after the denitrification step (S18). |
