热轧集装箱用钢表面缺陷分析

Analysis of surface defects of hot-rolled container steel

在热轧集装箱用钢的钢卷表面发现有细条状和近似圆点状的2种缺陷。通过对这2种缺陷进行EPMA、SEM和EDS等分析,并结合现场的轧制工艺情况,对这2种缺陷形成原因进行综合分析。分析结果表明:这2种缺陷都是在轧制过程中形成,由于集装箱用钢含Si量较高,造成除鳞难以去除,轧制油的油污与氧化铁皮压入形成了一种近似圆点的复合缺陷。

During the hot rolling process of container steel, two kinds of defects, i. e. thin-strip and dot-like black spot defects, were found on the hot-rolled strip surface. Through investigation using EPMA, SEM and EDS, and in consideration of the hot- rolling process in practice, the cause of formation of the surface defects were analyzed in a comprehensive way. The results showed that both defects occurred during hot rolling due to high Si content in the container steel which made it difficult for the oxide scale to be removed by normal descaling process. It was the rolling oil contaminated oxide scale embedded during hot rolling that caused dot-like compound defects.