CSP-冷轧热镀锌板表面线状缺陷特征及形成原因

Characteristic and Forming Reason of a Sliver-type Defect on the Surface of CSP-hot Galvanized Sheets

表面长条线状缺陷导致CSP-冷轧热镀锌板质量降低,利用金相显微镜、XRD和扫描电镜对缺陷的形貌与组成等进行了分析。长条线状缺陷的形成原因是:在CSP热轧阶段形成的氧化铁皮(FeO)被压入基板,并在冷轧时被拉长、碾碎,冷轧后,这些氧化物呈现出点链状直线分布,镀锌增强了其与基体的差别,凸现出长条线状缺陷。最后,据此提出了减少氧化铁皮压入的措施,抑制了长条线状缺陷的产生。

The quality of the CSP-hot galvanized sheets was decreased by some sliver-type surface defects. The morphology, structure and component of the defect were analyzed by using optical microscope, XRD and SEM-EDS. The results showed that the oxides （FeO） formed in CSP hot rolling led to the defect. The oxides were pressed in or e-longated in the surface layer of the steel in a centimeter-scale to meter-scale during hot rolling and cold rolling. Finally the oxides were rolled into point-chain shaped lines along the rolling direction. Appearance of the lines were intensified by galvanizing. Accordingly, the measures of reducing oxides on the surface of steel in production were supposed to elimi- nate the defect.