METHOD FOR MANUFACTURING CAST SLAB HAVING SOUND INTERNAL STRUCTURE BY STRAND-TO-STRAND CONTROL OF SPECIFIC FLOW RATE OF SECONDARY COOLING WATER FOR CONTINUOUS CASTING

摘要

PROBLEM TO BE SOLVED: To manufacture a cast slab having sound internal structure and increase the casting speed in the use of one continuous casting device having a plurality of strands, by restraining the bulging of a high-sulfur steel or a high-carbon steel having a wide solid-liquid coexistent phase, and by preventing internal cracking and eliminating segregation by applying light reduction at the terminal stage of solidification. SOLUTION: In the continuous casting of steel by one continuous casting device having a plurality of strands, specific cooling water flow rates in the secondary cooling zones are made different according to the bulging amount of steel on each strand. In one continuous casting device having three or more strands for example, the cast slabs in strands other than two end strands are relatively high in temperatures and their bulging amounts are relatively large. Accordingly the specific cooling water flow rates for the strands other than the two end strands are made 15-30% higher than those for the two end strands so that the bulging of the cast slabs in the strands other than the two end strands is restrained. COPYRIGHT: (C)2009,JPO&INPIT