To provide a control method of a plane shape in a thick plate rolling by which the trouble of conveyance and defect in length which are caused by the generation of a crop are mostly prevented and yield is more improved.
The thick plate rolling is performed by combination of forming rolling for applying the reduction of a plurality of passes to a steel slab, broadside rolling by which the reduction of the plurality of passes is applied after a material 1 to be rolled in this forming rolling is rotated 90° on a horizontal plane and finish rolling by which reduction of the plurality of passes is applied till the a thick plate having the target thickness is obtained after the material 5 to be rolled in this broadside rolling is rotated 90° on the horizontal plane. Where, the final pass of this broadside rolling is a stage where reduction is applied so as to make thickness difference in the direction of the pass and the length of a crop which is orthogonally crossed to the direction of the pass of the material 2 to be rolled just before the final pass of the broadside rolling, after all, measured values ΔLi, ΔLi', ΔLi" at a plurality of places along the direction of the pass are determined. By using these measured values, the rolling reductions ( Δhi, Δhi', Δhi" ) of the final pass of the broadside rolling are set.
NAKAMURA MASAMI
NISHIDA SHUNICHI
NISHIZAKI HIROSHI
Yoshiaki Naito
Cui Shu Tetsu