Patent ID: 8795443
Filing Date: 2014-08-05
Classification: B21B,C21D,C22C

Abstract:
1. A lacquer baked treated steel sheet comprising, on a percent by mass basis, 0.03% to 0.13% of C, 0.03% or less of Si, 03% to 0.6% of Mn, 0.02% or less of P, 0.1% or less of Al, 0.012% or less of N, at least one element selected from the group consisting of (1005% to 0.05% of Nb, 0.005% to 0.05% of Ti, and (10005% to (1005% of B, and the balance being iron and incidental impurities; a ferrite structure having a cementite ratio of 0.5% or more; the ferrite structure having an average ferrite crystal grain size of 7μm or less; a tensile strength of 450 to 550 MPa; a total elongation of 20% or more; and a yield elongation of 5% or less.