| 摘要 |
PURPOSE:To produce a plated steel sheet for the lower body of an automobile having superior corrosion resistance, by forming an Al alloy underlayer having a specified compsn. and a Zn alloy or Fe alloy layer as a base to be painted by plating on the surface of a low-C low-alloy steel sheet. CONSTITUTION:An Al alloy underlayer consisting of 1-30wt.% Mn, 0.5-20wt.% in total of one or more among Fe, Co, Ni and Cr and the balance Al is formed by plating by 5-40g/m<2> on the surface of a steel sheet having a compsn. contg., by weight, <0.03% C, 2,0-7.0% Cr, 0.05-1.0% Cu and 0.05-1.0% Ti and 0.05-1.0% Nb or further contg. 0.05-1.0% Ni. A layer of a Zn alloy such as Zn-Ni or Zn-Fe or an Fe alloy such as Fe-P, Fe-Ni or Fe-Mn as a base to be painted is then formed by plating on the Al alloy underlayer by 1-10g/m<2>. A plated steel sheet having superior weldability, corrosion resistance and suitability to chemical conversion treatment and suitable for the lower body members of an automobile is obtd.
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