带钢表面块状黑斑成因及对策

Cause analysis and countermeasures for black block mark on surface of hot rolled strip

针对热轧带钢表面存在的块状黑斑缺陷,利用扫描电镜等手段分析了其形貌、成分,得出条块状黑斑的产生是由于F_7机架出口处轧制烟尘与水蒸汽混合形成灰垢集聚在F_7机架出口下导板上,最后粘附于带钢下表面而形成条块状黑斑。通过加强侧喷和除尘水嘴日常维护,有效控制了带钢表面块状黑斑缺陷。

Aimed at the black block mark defect on the hot rolled strip surface,its morphology and chemical composition were analyzed by SEM.It concluded that the black block mark defect was caused by the compound of rolling fume dust and water vapor on the exit roller table after F7 mill,which was sticked on the bottom surface of strip.By enhancing side spray water and making good maintenance for the dust cleaner nozzle,the black block mark defect was effectly avoided.