Abstract
Galvanized steel sheets are increasingly used in the automotive industry due to excellent corrosion resistance, sufficient weldability, and formability. During sheet forming of galvanized metals, material failures such as exfoliation and cracking can be found in the zinc coated layers of the sheet under severe friction. Thus, the evaluation of the influences of surface topography, pressure, and lubrication on friction could provide valuable guidance in forming of galvanized metals. A hot-dip galvannealed sheet and a hot-dip galvanized sheet are chosen in this tribology study. The surface topographies of the materials are measured using profile meter and the fractal parameters are calculated using the fractal theory. The contact model between the sheet and the die is established using the real contact area. The friction model concerning the surface topography of galvanized sheet and the pressure is thus formulated. The friction coefficients of the theoretical values are in reasonable agreement with the experimental.