Method of manufacturing a slab continuous casting and flow control devices and flow control method of the molten steel in the mold

摘要

PROBLEM TO BE SOLVED: To obtain an excellent quality slab which contains few inclusions in a slab surface layer, regardless of casting speed in continuous steel casting.;SOLUTION: When the molten steel flow rate (u) in the molten metal surface in a mold exceeds a critical flow rate of powder entrapment of 0.32 m/sec., a moving magnetic field is applied so as to apply braking force to the discharge flow from an immersion nozzle for controlling the molten steel flow rate (u) to a predetermined rate. When the molten steel flow rate (u) is less than the critical flow rate of the inclusion adhesive of 0.20 m/sec. and equal to the critical flow rate of skinning on the molten metal surface of 0.10 m/sec. or more, the moving magnetic field is applied so as to rotate the molten steel in the mold horizontally for controlling the molten steel flow rate (u) within a range of 0.20 to 0.32 m/sec. When the molten steel flow rate (u) is less than the critical flow rate of skinning on the molten metal, the moving magnetic field (u) is applied so as to apply accelerating force to the discharge flow from the immersion nozzle for controlling the molten steel flow rate (u) within a range of 0.20 to 0.32 m/sec.;COPYRIGHT: (C)2004,JPO