| 摘要 |
An aspect of the present invention relates to a high strength cold-rolled steel sheet having excellent ductility and chemical treatment characteristics which includes, by area %, ferrite of 95-99% and martensite of 1-5% wherein C density of the martensite is 0.2-0.8 wt%, and Si density of a surface of the steel sheet and Si density at a depth of 0.5 mm from the surface of the steel sheet satisfy a following relation 1. [Relation 1] 1.1<=Si(0)/Si(0.5)<=1.7 (Here, Si(0) is mass% value of Si density of the surface of the steel sheet, and Si(0.5) is mass% value of the Si density at the depth of 0.5 mm from the surface of the steel sheet.) |
