Research on the Surface Topography Model of Galvanized Steels in Sheet Metal Forming

Due to the induced effect of plastic deformation and markedly influence of contact friction, the surface topography of galvanized steels has changed along with time and space during the sheet metal forming. WykoNT1100 non-contact optical profilometer was used to measure the surface topographies of different deformation zones in Erichsen cupping test. And the surface topography models of different deformation zones were established based on the statistical method. The results indicated that the surface topography was roughened with the increase of deformation and the degrees of roughening in different deformation zones were different. The function curve of micro-peak height in punch fillet zone which had serious deformation was relatively flat. It indicated that the data distributions were scattered, the roughness values were large and the zinc coating was severely exfoliated. However, the function curve in vertex zone was lanky with centralized data, small roughness values and intact zinc coating. Moreover, the surface topography was also affected by the contact friction.