High-strength steel sheet and the method for production therefor

A high-strength steel sheet comprising, 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 satisfying the following formulas 1 and 2, in which the element symbol indicates the content thereof in weight %, the prefactors representing the chromium or nickel equivalents, and the steel to be patented mainly consisting 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).