Patent ID: 6706419
Filing Date: 2004-03-16
Classification: C21D,C22C,C23C,Y10S,Y10T

Abstract:
A cold-railed steel sheet excellent in painting bake hardenability and anti aging property at room temperature characterized by: containing, in mass, 0.0001 to 0.20% of C, 2.0% or less of Si, 3.0% or less of Mn, 0.15% or less of P, 0.015% or less of S and, in addition, 0.10% or less of Al and 0.001 to 0.10% of N so as to satisfy the expression 0.52Al/N<5 and, further, one or more of 2.5% or less of Cr, 1.0% or less of Mo and 0.1% or less of V so as to satisfy the expression (Cr+3.5Mo+39V)&gE;0.1, with the balance consisting of Fe and unavoidable impurities; having the value of BH170, which is evaluated after applying a 2% tensile deformation and then a heat treatment at 170Â° C. for 20 min., equal to or more than 45 MPa, and any of the value of BH160, which is evaluated after applying a 2% tensile deformation and then a heat treatment at 160Â° C. for 10 mm., and the value of BH150, which is evaluated after applying a 2% tensile deformation and then a heat treatment at 150Â° C. for 10 mm., equal to or more than 35 Mpa; and having the yield point elongation at a tensile test after applying a heat treatment at 100Â° C. for 1 h. equal to or less than 0.6%.