MEHTOD FOR MAKING A Pb-Sn ALLOY PLATING STEEL SHEET WITH AN EXCELLENT CORROSION RESISTANCE

摘要

A method for plating Pb-Sn alloy onto the steel sheet is characterised by comprising coating Cr oxide on the Pb-Sn plated layer in the region of Cr depositing amount of 10-20 mg/m2, and applying a shear stress to horizontal direction of the plated layer in the range of strain amount of 1-100 % against the thickness of the plated layer. The method prevents the plated layer from pin-hole type corrosion without demage of lubricity and weldability. The steel sheet is useful for a fuel tank of a car.