Q235B钢热轧板带孔洞及边裂缺陷成因分析

采用宏观分析、化学成分分析、金相检验以及能谱分析等方法,对某钢铁公司生产的Q235B钢热轧板带中部孔洞和边裂缺陷的成因进行了分析。结果表明：该类热轧钢板的中部孔洞和边裂缺陷是由于连铸工艺出现异常,造成连铸板坯边部产生表层气孔以及中部产生较严重的硫偏析,从而使钢板中部生成了大量的条带状硫化物,特别是低熔点FeS的生成导致了中部孔洞缺陷的产生;而连铸板坯边部的表层气孔在轧制过程中导致了边裂缺陷的产生。

Causes Analysis on Center Cavities and Edge Cracks Defects of Q235B Steel Hot Rolling Plate

The formation causes of center cavities and edge cracks defects of Q235B steel hot rolling plate produced in an iron and steel company were analyzed by means of macro analysis,chemical compositions analysis,metallographic examination,energy spectrum analysis and so on.The results show that the center cavities and edge cracks defects were caused by the abnormal continuous casting which resulted in formation of surface pores at edge and serious sulphur segregation at center of the continuous casting slab.The serious sulphur segregation resulted in the formation of plenty of banded sulfide inclusions including low melting FeS,which led to the formation of center cavities defect during the hot rolling process.The surface pores at edge of the continuous casting slab led to the formation of edge cracks defect during the hot rolling process.