CSP热轧板卷边部裂纹成因初探

Exploration on Edge Crack of CSP Hot Rolled Coil

对CSP工艺生产的热轧薄板边裂原因进行了金相检测、SEM和能谱等方法分析,结果表明:边部裂纹上表面和横截面裂纹附近组织与试样其他部位相同,均为铁素体+少量渗碳体,无脱碳组织,裂纹处主要元素为O、Si、Ca,且分布细长,有压碎痕迹,推测其为压碎的CaSiO3夹杂,并发现裂纹处有保护渣成分,推测SPHC边部裂纹是在轧制过程中形成的,且是由卷渣带入的大颗粒的CaSiO3夹杂,在轧制过程中,应力集中导致板卷开裂。

By means of metallographic detection, SEM and energy spectrum analysis, the cause for edge crack of CSP hot rolled coil is analyzed. The result shows that., the upper surface and cross section near the crack has the same structure with other parts of sample, which are all ferrite, less cementite and no decarburization structure. The main elements in cracks are O, Si and Ca with the slender distribution and crush trace, which may be CaSiO3 in- clusion. And the casting powder is found in the crack, which is formed in the rolling process of SPHC. The stress concentration by large particles of CaSiO3 owing to slag entrainment are the main factors to produce crack of hot rolled strip coil.