MANUFACTURE OF COLD ROLLED STEEL SHEET EXTREMELY SUPERIOR IN PRESS FORMABILITY

摘要

PURPOSE:To manufacture the titled steel sheet, by hot rolling a steel having a specified compsn. composed of C, Si, Mn, Ti, P, Nb, S, Al, N, Fe, etc. under a suitable condition, and cold rolling said plate, then annealing continuously said sheet under a suitable temp. CONSTITUTION:The steel having an ingredient composed of 0.0005-0.0030% C, =0.2% Si, 0.04-0.5% Mn, (3.43N%+1.2X4C%)-(3.43N%+8X4C%) Ti, =0.030% P, 0.0025-0.015% Nb, =0.030% S, 0.002-0.1% SolAl, 0.0005-0.0060% N, and the balance Fe with inevitable impurities is cast continuously to a steel slab. Next, the slab is not rolled continuously while finishing it at =870 deg.C, and said plate is wound at =850 deg.C, next, pickled, cold rolled then, said sheet is annealed continuously at temp. of recrystallization temp. or above to =910 deg.C. By this way, the titled steel sheet is manufactured economically.