DOWNWARD CASTING METHOD

摘要

PROBLEM TO BE SOLVED: To produce a steel ingot of a high-quality while reducing gap in height of molten metal surfaces between each of molds.SOLUTION: When downward casting is carried with a downward casting device, casting ratio for casting into an injection tube is defined as 2 to 10 t/min, and ratio between the length of a runner at a first mold side and the length of a runner at a second mold side is designed within a range of 1:2.3 to 1:2.7, and an internal diameter D1 (mm) of a fine diameter part as the runner at the first mold side narrower than the internal diameter D2 (mm) of the runner at the second mold side meets a quartic equation D1 min≤D1≤D1 max, D1 max=D2×Wand a cubic equation D1 min=D2×W. The length L1 (mm)of the runner at the fine diameter part meets L1≥1.623D1×W-4.32 W+6.452D1+29.445. The distance L2 (mm) between an end position of the fine diameter part and a gate of the mold meets L2≥57.69×W(D3-D1)/D3. Wrefers to casting ratio (t/min). D3 refers to an internal diameter (mm) of the runner other than fine diameter part at the first mold side.