(1. Sheet Metal Research Institute, Shougang Research Institute of Technology, Beijing 100043, China 2. Hot-rolling Department, Shougang Jingtang United Iron and Steel Co., Ltd., Tangshan 063200, Hebei, China)
Abstract:Mountain-like defect was obviously found on the surface of the zinc layer during the galvanizing process of hot dip galvanized dual phase steel,which had very bad effect on the surface quality. There were the pretermission of plating,uneven zinc layer,and low-quality inhibition layer in the defect area,and the decarbonization,the microcracks and the burr were found on the substrate surface. Based on the analysis,the microcracks on the substrate surface were the basic reason for the mountain-like defect on the surface of hot dip galvanized dual phase steel. The microcracks of superficial zone in cold rolled sheet can be effective controlled by rapid heating with the lower target temperature,reducing the rolling temperature properly,decreasing the hot rolling thickness and the cold rolling reduction,and reasonably controlling the descaling and pickling process,which can solve the problem of the mountain-like defect on hot dip galvanized dual phase steel.