HIGH-STRENGTH COLD-ROLLED STEEL SHEET EXCELLENT IN UNIFORM ELONGATION AND METHOD FOR MANUFACTURING SAME

摘要

A high-strength cold-rolled steel sheet excellent in uniform elongation, including in percent by mass:
0.10 - 0.28 % of C;
1.0 - 2.0 % of Si; and
1.0 - 3.0 % of Mn,
and the structures of the same having the space factors below to the entire structure:
30 - 65 % of bainitic ferrite;
30 - 50 % of polygonal ferrite; and
5 - 20 % of residual austenite.