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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.

The effects of working mode, coating weight, thickness of substrate and iron content of coating on the peeling-off resistance of zinc and iron-zinc coatings have been investigated using a draw bead tester, which was designed to evaluate the peeling-off phenomena of coated materials. In the test, specimens are subjected to both bending-unbending deformation and the slide caused by the bead tip. The test was conducted under several working modes; i.e., proportion of the deformation to the slide was changed by altering draw bead conditions. The draw bead results showed that Fe-Zn coating were mainly peeled off by the deformation, while Zn coatings were removed chiefly by the slide. It was also revealed that the amount of peeling-off of the coatings was considerably affected by the working mode. The peeling-off resistance of galvannealed steel sheets was then investigated by the test.