Patent ID: 7767036
Filing Date: 2010-08-03
Classification: C21D,C22C,C23C,Y10T

Abstract:
1. A high-strength cold-rolled steel sheet having a matrix comprising bainitic ferrite and residual austenite, wherein said high-strength cold-rolled steel sheet comprises: 0.10-0.25 wt. % C; 1.0-2.0 wt. % Si; 1.5-3.0 wt. % Mn; 0.01 wt. % or less, not including 0 wt. %, P; 0.005 wt. % or less, not including 0 wt. %, S; 0.01-3.0 wt. % Al; and balance consisting of iron and impurities, wherein said bainitic ferrite exhibits a space factor within said matrix of 70% or more, wherein said residual austenite exhibits a space factor within said matrix of 5-20%, wherein said high-strength cold-rolled steel sheet exhibits a Vickers hardness number of 270 or greater, and wherein an X-ray diffraction peak on a (200)-surface of α-iron has a half-value width of 0.220 degrees or less.