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A galvannealed steel sheet (GA) with a Ni-base inorganic lubricant film has been developed to meet the needs of the automotive industry, especially for improved press formability. This paper describes the results of tests performed to evaluate formability, spot weldability, phosphatability, paintability and corrosion resistance of the GA with the Ni-base lubricant film. The coefficient of friction as measured by flat sliding test decreases with increasing Ni content in the lubricant film. The spot weldability evaluated by electrode tip life test is slightly improved after the application of the lubricant film. Phosphatability, paintability and corrosion resistance of the GA with the lubricant film are equivalent to those of GA without the lubricant film.

Zinc-manganese alloy electroplated has been developed for automotive body panel applications. The product is manufactured on a conventional electrogalvanizing line using an electrolyte containing zinc sulfate, manganese sulfate and sodium citrate. Electroplated steel with an alloy content of 30-50% manganese exhibits excellent corrosion resistance both as-produced and after painting. Zinc-manganese coatings also show good workability and voidability. Accordingly, this product is suitable for both unexposed parts and the interior surfaces of exposed parts. Finally, zinc-manganese electroplated steel displays good wet adhesion and anti-cratering characteristics so that the product can also be used for exposed applications as automotive body panels.