A method of manufacturing a molding process for high-strength steel sheets

摘要

PURPOSE: To obtain a high strength steel sheet reduced in plane anisotropy, having low yield ratio, perfect non-aging characteristic, and high r-value, and practically free from softening due to heating at high temp. ;CONSTITUTION: The steel sheet is a high tensile strength steel sheet for forming having a composition containing, by weight, 0.01-0.1% C, 0.1-1.2% Si, ≤3.0% Mn, Ti by an amount in the range where the value of (Ti%-1.5S%-3.43N%)/C% becomes 4 to 12, 0.0005-0.005% B, ≤0.1% Al, ≤0.1% P, ≤0.02% S, and ≤0.05% N. A slab of a steel having the above composition is heated at a temp. in the range of 1100-1280°C and hot-rolled into a steel plate. Further, the above hot rolled plate is subjected to cold rolling and annealing so as to be formed into a steel sheet. Moreover, plating treatment is applied to these steel plate and steel sheet so as to be formed into plated steel plate and plated sheet.;COPYRIGHT: (C)1993,JPO&Japio