STEEL CONTINUOUS CASTING METHOD FOR STEEL

To provide a continuous casting method for a steel capable of reducing porosities in a slab.SOLUTION: A continuous casting method for a steel has a process where, while injecting a molten steel 9 into a cooled mold 5 for continuous casting, the molten steel 9 is solidified to form a slab 10, and the slab 10 is pulled out from the mold 5. Next, cooling water is sprayed toward the slab 10 to solidify the molten steel 9 in the slab 10, and then, the slab 10 is depressed. At a position in which the depression is started, the surface temperature of the slab 10 is controlled to 600°C or lower, and also, a difference between the temperature of a slab center and the above surface temperature is controlled to 400°C or higher, and, at a solidification completion position 13 in which the solidification of the molten steel 9 in the slab 10 is completed, the solidification structure of the central part in a slab thickness direction is formed of columnar crystals and/or branched columnar crystals. The slab 10 is depressed by 5 mm or higher.SELECTED DRAWING: Figure 1 【課題】鋳片内のポロシティを低減することが可能な鋼の連続鋳造方法を提供する。【解決手段】鋼の連続鋳造方法では、冷却されている連続鋳造用鋳型５に溶鋼９を注入しつつ、溶鋼９を凝固させ鋳片１０を形成し、鋳片１０を鋳型５から引き抜く。次いで、鋳片１０に向けて冷却水を吹付けて鋳片１０内の溶鋼９を凝固させてから鋳片１０を圧下する。圧下を開始する位置で、鋳片１０の表面温度を６００℃以下且つ鋳片中心の温度と前記表面温度との差を４００℃以上とし、鋳片１０内の溶鋼９の凝固が完了する凝固完了位置１３において鋳片厚み方向中心部の凝固組織を柱状晶及び／又は分岐柱状晶とする。鋳片１０を５ｍｍ以上圧下する。【選択図】図１