METHOD FOR PRODUCING COLD ROLLED STEEL PLATE HAVING NON-AGING CHARACTERISTIC AND EXCELLENT DEEP DRAWABILITY AND HAVING LESS ANISOTROPY OF R VALUE IN PLATE PLANE BY CONTINUOUS ANNEALING

摘要

PURPOSE:To produce a cold-rolled steel plate which has non-aging characteristic and excellent deep drawability by subjecting an aluminum-killed steel slab contg. limited compsns. of C, Mn, and Sol.Al to a heat treatment then to hot rolling and cold rolling followed by continuous annealing. CONSTITUTION:The aluminum-killed steel slab consisting of 0.0010% =C= 0.0035%, =0.45% Mn, =0.015% Sol.Al=0.090% is heated or soaked at = 1,100 deg.C prior to continuous hot rolling and in held at this temp. to allow the greater part of Al N to deposit, then the slab is subjected to continuous hot rolling and coiling. After the hot-rolled steel plate is cold-rolled, the cold-rolled steel plate is heated quickly and is held for a short time at 680-900 deg.C soaking temp., following to which the plate is cooled and annealed continuously, whereby the cold-rolled steel plate which has non-aging characteristic and excellent deep drawability, has high r value and less anisotropy of the r value in the plate plane and is further free from cracking by secondary operations is produced with the simple stages.