Patent ID: 9109273
Filing Date: 2015-08-18
Classification: C21D,C22C

Abstract:
1. A high strength cold rolled steel sheet comprising, by weight percent, 0.05 to 0.3% C, 0.3 to 1.6% Si, 4.0 to 7.0% Mn, 0.5 to 2.0% Al, 0.01 to 0.1% Cr, 0.02 to 0.1% Ni and 0.005 to 0.03% Ti, 5 to 30 ppm B, 0.01 to 0.03% Sb, 0.008% or less S, balance Fe and impurities, and comprising a microtexture including 40 to 50% by area fraction of annealed martensite as a matrix, 20 to 40% by volume fraction of retained austenite and balance ferrite.