CSP热轧板卷边部裂纹成因

Edge cracking causes of hot rolled strips produced by CSP

摘要: 用光学显微镜、扫描电镜、透射电镜和能谱分析等方法研究了涟钢CSP热轧板卷边部裂纹的成因.结果表明:连铸坯表面的深振痕是热轧板卷边部裂纹的起源,连铸坯角部过冷导致奥氏体晶界AlN的细小析出,加剧了连铸坯对裂纹的敏感性.连铸坯经过精轧机组的轧制后,连铸坯表面的横裂纹扩展成为热轧板卷的锯齿状裂纹,严重时会造成烂边或掉块.

Abstract: The edge cracking causes of hot rolled strips produced by CSP were investigated by optical microscope (OM), scanning electron microscope (SEM), transmittion electron microscope (TEM) and energy-dispersive X-ray analysis (EDX). The results indicated that deep oscillations of thin slabs were the origin of the edge cracks of hot rolled strips and AIN precipitates around the prior austenite grain boundaries due to intensive cooling rate rendered the slabs more susceptible to cracks. After seven rolling stands, the transverse cracks of the slabs would propagate to serrated edge cracks, even drop-out type cracks of hot rolled strips.