Cause analysis of stripe defects on the surface of hot-dip galvanized strip steel
ZENG Song-sheng 1，2， WU Run 1， QI Qi-song 2， LI Ming-wei 1
1.College of Materials and Metallurge， Wuhan University of Science and Technology， Wuhan 430081， China；
2. Hunan Valin Arcelor Mittal Automotive Steel Co.， Ltd.， Loudi 417009， China
Abstract：Various defects such as leakage plating， and black spot are often observed on the surface of strip steel during the production of hot-dip galvanized strip steel. Among them， the stripe defect is one type of defect. The stripe defect of on the surface of hot-dip galvanized strip steel was tested and analyzed by scanning electron microscope （SEM） and energy disperse spectroscopy （EDS）. The results showed that there were cracks in the substrate at the location of the stripe defect， which caused layering at the inner layers of the substrate. There were iron scale， oxidized dots and galvanized layer within the crack of substrate at the same time， and the surface coating was thin. The defect should be caused by longitudinal crack on the surface of continuous casting slab and subsequent hot rolling. This defect on the surface of galvanized sheet not only affected the appearance of the strip steel， but also easily caused coating peeling and delamination in stamping process， and finally leading to the scrap of workpieces.
2020, Vol. 38 
