METHOD FOR CONTINUOUSLY CASTING THIN CAST SLAB

PURPOSE:To enable the continuous casting to be performed uniformly while solidifying a thin cast slab without causing a longitudinal crack in the thin cast slab by uniformizing the extents of size of the eddies of four turnover flows developed at the time of pouring molten steel and making the turnover flows a confluent flow at the center of a flat nozzle. CONSTITUTION:In the casting of the thin cast slab by a twin belt type continuous casting machine, the molten steel 7 is poured into a mold 1 through two flat nozzles 9a, 9b. The two flat nozzles 9a, 9b are arranged in parallel to the long side of the mold 1 toward the short side in series aligning the thickness center of the nozzles to the thickness center of the mold 1 and the width center position (x) of the respective flat nozzles 9a, 9b and the immersion depth (y) into the molten steel 7 are set within the specific range. The extents of size 2R of respective four turnover flows A, B, C, D developed at the time of pouring the molten steel 7 are made equal to each other to make these turnover flows confluent flow at the center of the respective flat nozzles 9a, 9b, and the thin cast slab without longitudinal crack can continuously be cast.