| 摘要 |
<p>PURPOSE:To provide superior corrosion resistance, workability, weldability, and chemical conversion treating property by forming an Ni-P alloy plating layer on the surface of a steel sheet of specific composition for deep drawing, applying heat treatment, and forming a diffused alloy region. CONSTITUTION:The cold rolled steel sheet for deep drawing has a composition consisting of, by weight, 0.002-0.01% C, <=1% Si, 0.05-1% Mn, 0.02-0.1% P, <=0.01% S, <=0.1% sol.Al, <=0.004% N, 0.0005-0.002% B, 0.2-0.5% Cu, 0.1-0.5% Ni, 0.002-0.05% Sn, and the balance Fe with inevitable impurities. In this composition, a relationship represented by inequality is satisfied, and further, either or both of 0.005-0.1% Ti and 0.002-0.05% Nb are incorporated. A plating composed essentially of Fe-Ni-P is formed at least on one side of this steel sheet and heat treatment is done in a nonoxidizing atmosphere, by which a diffused alloy layer is formed.</p> |
