High-strength steel sheet and the method for production therefor

摘要

A high-strength steel sheet comprises, by weight, not less than 0.25% and not more than 0.5% of C, not less than 4% and not more than 14% of Mn, not less than 6.5% and not more than 9.5% of Cr, and not less than 0.3% and not more than 3% of Si. The high-strength steel sheet satisfies formulas 1 and 2, formula (1) being 12≦2.0Si+5.5Al+Cr+1.5Mo≦25 and formula (2) being 13≦30C+0.5Mn+0.3Cu+Ni+25N≦17, and mainly consists of austenite, and the high-strength steel sheet has yield strength of not less than 1000 MPa and total elongation of not less than 20%. In formulas 1 and 2, each element in the above formulas indicates the content, in weight %, of the element.

主权项

1. A high-strength steel sheet consisting of, by weight:
not less than 0.25% and not more than 0.5% of C, not less than 4% and not more than 14% of Mn, not less than 6.5% and not more than 9.5% of Cr, and not less than 0.3% and not more than 3% of Si, not less than 0.005% and not more than 0.05% of N, not less than 0.05% and not more than 4% of Al, not less than 0.1% and not more than 4% of Ni, not less than 0.05% and not more than 3% of Mo, and not less than 0.1% and not more than 2% of Cu, balance of Fe and inevitable impurities; the high-strength steel sheet satisfying the following formulas 1 and 2, in which the element symbol indicates the content thereof in weight %, the prefactors representing the chromium and nickel equivalents, and the steel consisting essentially of austenite; and the high-strength steel sheet having a yield strength of not less than 1000 MPa and total elongation of not less than 20%
12≦2.0Si+5.5Al+Cr+1.5Mo≦25  (1)13≦30C+0.5Mn+0.3Cu+Ni+25N≦17  (2).