IF钢冷轧板表面条状缺陷

Surface Sliver Defect of Cold-Rolled IF Steel Sheet

用扫描电镜、化学和小样电解法分析了IF钢冷轧板表面条状缺陷特征及成因。结果表明：该缺陷附着在铁基体表面，凸凹不平，呈不连续分布；缺陷表面粗糙，形状不规则，与基体边界清晰，内部分散着直径2～5μm的细小颗粒。缺陷是由发生堵塞的水口内壁附着的大型Al2O3夹杂物在非稳态浇注条件下被卷入凝固坯壳所致，夹杂物原始尺寸约4．9mm。

The character and cause of sliver defect on IF steel sheet surface are studied by means of SEM, chemical analysis and electroanalysis. The results show that the sliver defect attaches to the steel base and it is scraggly and it is not distributed continuously. The surface of the defect is rough, there is clear boundary between the defect and the steel base and small particles scatter in it. The defect is caused by large Al2O3 inclusion which attaches to the inner surface of clogged submerged nozzle when the casting condition is not steady and the original size of the inclusion is 4.9 mm. This kind of defects is eliminated by means of nozzle clogging control and unsteady casting condition control.