Patent ID: 8449699

Claim:
A cold-rolled steel sheet comprising, on a percent by mass basis: C: 0.0010% to 0.0030%, Si: 0.05% or less, Mn: 0.1% to 0.3%, P: 0.05% or less, S: 0.02% or less, Al: 0.02% to 0.10%, N: 0.005% or less, and Nb: 0.010% to 0.030% and the remainder composed of Fe and incidental impurities, wherein values in a rolling direction and a direction perpendicular to the rolling direction are within a range of 1.0 to 1.6, and a mean value El m of elongations in the rolling direction, a direction at 45° with respect to the rolling direction, and the direction perpendicular to the rolling direction is 40% or more, where El m =( El L +2 ×El D +El C )/4 El L : elongation in the rolling direction El D : elongation in the direction at 45° with respect to the rolling direction El C : elongation in the direction perpendicular to the rolling direction.