使用扫描电子显微镜、能谱仪、光学显微镜等设备,对合金化热镀锌无间隙原子钢板表面白色点状压印缺陷进行分析,查明了该缺陷的产生原因。结果表明:该缺陷表面合金化不充分,平整印较多,锌层局部偏厚,部分溶锌后发现有氧化铁皮;钢板表面氧化铁皮局部偏厚,酸洗时氧化铁皮未能被完全溶解,并压在钢板表面,镀锌合金化后呈白色点状压印形貌。采用降低卷取温度的方法,可有效减小钢板表面氧化铁皮的厚度,后续钢板未再发现该类缺陷。

The white dot imprint defects on the surface of alloyed hot dip galvanized interstitial free atomic steel sheet were analyzed by using scanning electron microscope, energy dispersive spectrometer and optical microscope, and the cause of the defects was found out. The results show that the surface of the defect was not fully alloyed, there were many flat prints, the zinc layer was partially thicker, and iron oxide scale was found after partial zinc dissolution. The iron oxide scale on the steel plate surface was partially thick, and the iron oxide scale could not be completely dissolved during pickling, and it was pressed on the steel plate surface. After galvanizing and alloying, it showed a white dot impression. By reducing the coiling temperature, the thickness of iron oxide scale on the steel plate surface was reduced effectively, and no such defect was found on the subsequent steel plate.