PRESS DIE FOR WIDTH REDUCTION OF STEEL SLAB

PROBLEM TO BE SOLVED: To prevent generation of a fine wrinkle on upper/lower faces of a width end part while maintaining centering, twisting prevention effect and width bulging suppression effect. SOLUTION: A guide groove 6, in which a width is narrower toward depth and a bottom width d2 is larger than a slab thickness S, and a reduction groove 7 (depth h2 ), in which the bottom of the guide groove 6 is made as a opening face and a cross sectional face is roughly M shaped, are formed on the face facing the side end face of a steel slab 10, the top (height h1 ) of a projecting part 5 of a center part of the reduction groove is made the same level as or deeper than the opening face (that is, h2 >=h1 ) and the deepest part total width d0 including a projecting bottom part of the reduction groove is made larger than the slab thickness.