Application of Hot-Dip Zn-6%Al-3%Mg Alloy Coated Steel Sheet to Automotive Body

Nisshin steel has succeeded in the commercial production of a hot dip Zn-6%Al-3%Mg alloy coated steel sheet (ZAM) produced by continuous galvanizing. ZAM has a coating layer containing high content of Mg and so it has good bare corrosion resistance. The purpose of this paper is to show results from investigations aimed at evaluating ZAM for application in automotive body panels. Through tests for paintability, corrosion resistance, spot weldability and press formability, it is confirmed that ZAM shows good performance. This is especially true in terms of cosmetic and perforation corrosion resistance, when its performance is compared with that of galvanized (GI), electrogalvanized (EG) and galvanneal (GA) which are currently used in automotive bodies.