Method for producing ultra-thin steel sheet for 2-piece can with excellent in-plane anisotropy and in-plane anisotropy uniformity in coil

摘要

PROBLEM TO BE SOLVED: To produce a steel sheet for a two-piece can excellent in intra-plane anisotropy and excellent in the intra-plane anisotropy over the whole length and whole width in a coil. SOLUTION: A continuously cast slab contg. 0.001 to 0.005% C, =0.1% Si, 0.1 to 1.5% Mn, =0.02% P, =0.02% S, 0.02 to 0.15% sol.Al and =0.005% N is rough-rolled at a draft of =70% in the temp. range above the Ar3 transformation point to form it into a rough bar and after flatness degree of the rough bar is straightened, in the inlet side of a hot finish rolling mill, heating for the edge parts only by an edge heater and heating for the whole in the width direction by an induction heating apparatus are executed, to control the temp. on an inlet side in finish rolling of the rough bar and thereafter, to carry out hot finish rolling so that the tamp. on an outlet side in the finish rolling becomes 895 to 925 deg. C from the tip part to the rear end part of the steel strip and the finished sheet thickness becomes =2.3 mm. The steel strip is coiled at 600 to 700 deg.C, is pickled, is thereafter cold-rolled at a draft of 85 to 95%, is annealed and is subsequently performed to skinpass rolling or secondary rolling to form it into the steel strip of =0.25 mm sheet thickness and next, to performed it to surface treatment.