CHARACTERIZATION OF GALVANIZED SHEET STEEL FOR AUTOMOTIVE VEHICLE BODIES

摘要

Commercially available galvanized steel sheet materials representing zinc coatings of conventional spangles, minimized spangles, and of diffusion alloy (galvanneal), were characterized for quality and performance. Thicknesses of the galvanize coatings were determined by chemical stripping (procedures for which are offered), by microscopic examination of cross-sectioned specimen, and by magnetic and eddy-current measuring devices. Corrosion resistances of the galvanized steels were determined following specific periods of exposure of specimens in five percent salt-fog environment. Bead and spot welding of the galvanized sheets were successfully performed. The amenability of the various materials to forming or shaping without flaking of, or other damage to, the coating was demonstrated. Conclusions regarding the suitability of the test methods and their adoption generally are offered. Recommendations for: use of the materials, application of preferred thickness measuring methods, and acceptance of corrosion resistance qualifying criteria, are presented. (Modified author abstract)