酒钢冷轧低碳钢薄板表面“黑线”缺陷成因及控制

Cause and Control of Surface“Black Line”Defects of Cold-Rolled Low Carbon Sheet in JISCO

对酒钢CSP冷连轧机组生产的低碳钢薄板表面出现的长、短两类"黑线"缺陷进行了光学显微镜(OM)和扫描电镜(SEM)形貌观察及能谱仪(EDS)成分测定,并结合生产工艺分析确认,"长黑线"缺陷是连铸环节产生的外来夹杂物在冷轧后暴露所造成的,"短黑线"缺陷是由于CSP均热炉炉辊辊环结瘤造成热轧板下表面氧化铁皮压入产生的。据此,提出相应的解决措施并优化生产工艺。改进后冷轧板表面质量合格率提高了6%。

The surface defects of long and short ＂black line＂ appeare on the low carbon steel sheet from the CSP cold rolling process in JISCO were analyzed by optical microscopy （OM）, scanning electron microscopy （SEM） and en- ergy dispersive spectroscopy （EDS）. Combining the analysis of production processes, it shows that the ＂long black line＂ defect is caused by foreign inclusions formed during continuous casting and exposed after cold rolling. The＂ short black line＂ defect is due to the rolled-in oxide scale in the bottom surface of hot-rolled plates, which is caused by the roll ring nodulation in soaking furnace. Based on the result, the corresponding solutions to improve produc- tion processes were suggested. After improving, the surface qualified rate of the cold-rolled sheet increases by 6 .