Diffusion Behavior of Al in Zn Coating Layer of Zn-0.2mass%Al Hot-dip Galvanized Steel Sheets with and without Temper Rolling during Aging after Production

It is known that Al added to the Zn coating layer of hot-dip galvanized steel sheets (GI) diffuses surface at room temperature and forms Al-based oxides in air. In order understand diffusion behavior layer, this study investigated effect aging on segregation GI with without temper rolling (skinpass rolling) using a material weight about 56 g/m2 an content approximately 0.20 mass%. The specimens were aged -15, 5, 20, 38, 100 or 200 ºC air after production, cross sections observed analyzed by XRF, SEM-EDX, EBSD TEM. As result, up 38 ºC, amount increased linearly square root time, suggesting formation rate determined range. However, linear relationship did not hold temperatures above °C. addition, temper-rolled GI, larger than then decreased drastically discussed view changes macrostructure during production.