Reasons and Preventive Measures for Pock Flaws on Coating Surface of Galvanized Steel Sheet

The surface and cross-section of the pock flaws which appeared on the hot-dip galvanized coating were observed and analyzed by using SEM and energy spectroscopy.Results indicated that the pock flaws were caused by the granules of ferric oxide,which floated in the liquid zinc and were easily adhered on the coating surface.These defects could be controlled and decreased by taking effective preventive measures in the production process of hot-dip galvanizing.