冷轧带钢表面起皮缺陷分析

Analysis of Peeling Defect on the Surface of Cold-rolled Strip

利用扫描电镜(SEM)、能谱仪(EDS)和金相显微镜观察冷轧带钢表面起皮缺陷处的微观组织,分析冷轧带钢表面起皮缺陷的形成机理,探究控制起皮缺陷的主要措施。结果表明:冷轧带钢表面起皮的主要原因为夹杂物、皮下气泡及擦伤;夹杂物主要为结晶器保护渣、耐火材料形成的夹渣及钢中氧化物与夹渣的反应产物,通过提高钢水纯净度、控制钢水成分可减少钢中夹杂物的产生;轧制时基体中的气泡受压力作用从表面逸出,产生针孔状或蜂窝状缺陷,通过缩短钢水在空气中的滞留时间、保证吹氩质量等可减少气泡缺陷;钢卷在开卷、卷取及吊运过程中,钢卷层与层间产生的相对滑动会引起擦伤类缺陷,通过采用合理的工作机组及工艺参数可避免此类缺陷。

The cause of peeling defect on the surface of cold-rolled strip,the formation mechanism of peeling defect were analyzed with scanning electron microscope(SEM),energy disperse spectroscopy(EDS)and metallographic microscope,and the main measures to control peeling defect were explored.The results show that the main causes of surface peeling of cold-rolled strip are inclusions,subcutaneous bubbles and scratches.The inclusions are mainly mold slag,slag formed by refractory materials,and the reaction product of oxides and slag in steel.By improving the purity of molten steel and controlling the composition of molten steel,inclusions in steel can be reduced.The bubbles in the matrix escape from the surface under the pressure during rolling,result in pinhole or honeycomb defect.By shortening the retention time of molten steel in the air and ensuring the quality of argon blowing can reduce bubble defect.In the process of uncoiling,coiling and lifting of steel coil,the relative sliding between the steel coil layers will cause scratch defect,which can be avoided by adopting reasonable working units and process parameters.