Patent ID: 8293379
Filing Date: 2012-10-23
Classification: C22C,Y10T

Abstract:
1. A steel sheet of a steel alloy composition comprising: iron (Fe); carbon (C) in an amount of 0.15 to 0.30 wt %; silicon (Si) in an amount of 0.05 to 0.5 wt %; manganese (Mn) in an amount of 1.0 to 2.0 wt %; boron (B) in an amount of 0.0005 to 0.0040 wt %; sulfur (S) in an amount of 0.003 wt % or less; phosphorus (P) in an amount of 0.012 wt % or less; one or both of calcium (Ca) and copper (Cu), calcium being in an amount of 0.0010 to 0.0040 wt %, copper being in an amount of 0.05 to 1.0 wt % of copper (Cu); and two or more selected from the group consisting of cobalt (Co), zirconium (Zr) and antimony (Sb), wherein the cobalt (Co) and the antimony (Sb) are present in amounts to satisfy 0.0005 wt %≦(Co+Sb)≦0.5 wt %, wherein the steel alloy composition does not comprise any one of Titanium (Ti), Niobium (Nb), Molybdenum (Mo) and Chromium (Cr).