| 摘要 |
PROBLEM TO BE SOLVED: To stably produce a multi-layer cast slab capable of easily controlling the supply of molten steel and having no unevenness of solute element concentration over the width direction on the surface layer part of the cast slab. SOLUTION: When the molten steel is poured by using a single immersion nozzle in the state that DC magnetic field is impressed over the whole width of the cast slab in the thickness direction of the cast slab at the position aparted dounwardly in a fixed distance from the molten steel surface level in a continuous casting mold, the immersion nozzle is arranged at the position satisfying both of the following formulae (1) and (2) and also, a specified solute element is added into the position satisfying both of the following formulae (3) and (4). h<(1/2).w.tanθ...(1), 0<h<=0.3...(2), 0<z<=0.5...(3), -0.3<=y<=0.3...(4). Wherein,θis the downward angle ( deg.) of the spouting hole in the immersion nozzle, w is the length (m) in the width direction of the mold, h is the downward distance (m) from the lower end of the spouting hole in the immersion nozzle to the center in the height of a magnetic pole, z is the distance (m) from the adding position of the solute element to the center in the height of the magnetic pole and y is the distance (m) in the horizontal direction from the spouting hole in the immersion nozzle to the adding position of the solute element.
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