In order to solve the problem that the surface of galvannealed steel sheet is easy to appear the white spot color difference stripe defect in the actual production process,the morphology and composition of the normal part and the white spot defect part were compared and analyzed,the formation mechanism of white spot defect was revealed and the improvement measures were put forward.The results show that the white spot on the surface of the gray coating is normal dark gray on the edge and obvious white strip in the middle,and the white spot is actually an underalloying defect,the underalloying in the middle of strip is mainly caused by C-warpping in the head of strip,which results in the coating thickness on the upper and middle of strip being larger than that on the lower surface,and the Fe content on the upper surface is lower.By optimizing laminar cooling,strictly control-ling the roll diameter of temper mill,increasing the tension of cooling section and reducing the pressure of correcting roll of zinc pot,the C-warping defect of strip was effectively improved,achieving good results.
维普
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