IF钢冷轧板表面条状缺陷成因及控制

Genesis and Control of Surface Sliver Defects of IF Steel Cold Rolled Sheets

条状缺陷是IF钢冷轧板常见的表面缺陷之一,针对邯钢IF钢冷轧板表面出现的条状缺陷,分析了该类条状缺陷的成因,并提出了合理的控制措施。通过SEM-EDS分析发现条状缺陷内部存在大量的小尺寸Al_2O_3颗粒,分析其来源于铸坯中大型Al_2O_3夹杂物。对不同浇注阶段铸坯进行SLIME法大样电解并采用SEM-EDS分析其大型夹杂物类型,发现在交接坯和换水口坯中存在较多的大型Al_2O_3夹杂物,分析其来源为水口结瘤物。综合分析后得出此类条状缺陷成因是水口结瘤物脱落被卷入结晶器,并在铸坯中形成大型Al_2O_3夹杂物,进而在冷轧板轧制过程中形成表面条状缺陷。

Sliver defect is one of the most common defects in IF steel cold rolled sheet. In this paper, the genesis of cold rolled IF steel sheet sliver defects in Handan Iron Steel Group have been studied, and some methods of reducing sliver defects have been proposed. SEM-EDS result indicates that there are a large amount of small-sized Al2O3 particles in the sliver defects. According to SLIME results of slabs at different casting stages , there are high amount of large-sized Al2O3 inclusions in ladle changing and SEN changing slabs, which originate from the drop off of clogs in entry nozzle. Therefore, it can be concluded that the clogs in entry nozzle drop off into mould and develops as a large-size Al2O3 inclusion in the slabs, which causes surface sliver defects during cold rolling process.