热浸镀锌带钢表面条纹状缺陷产生原因分析

在生产热浸镀锌带钢时，带钢表面经常出现漏镀、黑点等各种缺陷，条纹状缺陷也是其中一种。采用扫描电镜和能谱仪对连续热浸镀锌带钢的镀层表面条纹状缺陷进行了测试与分析。研究表明，该条纹状缺陷位置处基板内存在裂缝，导致基板内表层出现了分层，裂缝内同时存在基板的氧化铁皮、氧化圆点和镀锌层，表面镀层较薄，该缺陷应为连铸板坯表面存在纵裂纹以及后续热轧轧制所致。镀锌板表面出现该缺陷后，不仅影响板面外观，而且在冲压成形过程中易发生镀层剥落和起皮而导致工件报废。

Cause analysis of stripe defects on the surface of hot-dip galvanized strip steel

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.