连续退火板表面鱼鳞纹缺陷形成机理分析及改进措施

采用扫描电镜及聚焦离子束分析对连续退火板表面鱼鳞纹缺陷的形貌及微观组织进行了分析。结果表明,鱼鳞纹缺陷的实质是一类表面微擦伤,其形成机理是因板温计水冷套漏水,导致带钢表面在高温下形成局部氧化,氧化部位在带钢张力作用下与炉辊辊面形成微擦伤。通过聚焦离子束技术在缺陷处沿截面切开后观察到组织中有大量纳米级亚晶结构的形成,证实了带钢表面受急冷并氧化的推断。微观组织分析结果为缺陷的现场排查和解决提供了理论依据。

Analysis and improvement of fish scale defect formation mechanism on continuous annealed plate surface

The morphology and microstructure of the fish scale defects on the surface of continuously annealed plates were analyzed by means of scanning electron microscopy and focused ion beam analysis. The results show that the essence of the scale defects is a kind of surface micro scratch. The formation mechanism of the defects can be attributed to the water leakage of the thermometer water jacket, which causes the local oxidation of the strip surface at high temperature. And then, the micro scratch formed when the oxidation part was pressed by the furnace roll and the strip tension. A large number of nanocrystalline structures were observed at the defect section cutting by focused ion beam technology, which confirmed that the surface of the strip was quenched and oxidized. The results of the microstructure analysis provide a theoretical basis for the investigation and solution of the scale defects.