SECONDARY COOLING METHOD OF CONTINUOUS CASTING SLAB

PROBLEM TO BE SOLVED: To provide a secondary cooling method of a continuous casting slab, in which occurrence of a surface crack (a corner crack) and an inner crack (a horizontal crack) is prevented by the cooling method of the slab only, without sacrificing productivity of a continuous casting apparatus and without modifying a component system of the slab.SOLUTION: In a secondary cooling method of a continuous casting slab, width cutting not spraying secondary cooling water 25 is performed at both end parts of a long side 21a of an upper surface side of a cast slab 5 in at least a part of a casting segment from immediately after a bent part 13 to a solidification completion position in a continuous casting apparatus, whereas a total width including both end parts of the long side 21a of a lower surface side of the cast slab 5 is sprayed with the secondary cooling water 25 in the casting segment from immediately after the bent part 13 to the solidification completion position.