在SPHD热轧带钢边部发现有翘皮缺陷。通过宏观检验、化学成分分析、金相检验、扫描电镜及能谱分析等方法对带钢边部翘皮的原因进行了分析。结果表明:连铸时结晶器内的保护渣卷入铸坯表层,轧制变形后被拉长存在于带钢皮下表层是引起SPHD带钢翘皮缺陷的主要原因。SPHD带钢经过粗轧道次的变形,中间坯角部低温区在一定的立辊侧压作用下产生了超出板坯材料热塑性容限的变形,形成角部裂纹,这种裂纹在随后的轧制过程中不能被焊合,形成沿轧制方向断续迭层分布的翘皮缺陷,并随中间坯侧边“翻边”过程的进行向板坯上下表面翻转,最终分布在热轧板边部区域。

Shell was founded at the edge of SPHD hot-rolled strip steel. The reason of shell was analyzed by means of macro examination, chemical composition analysis, metallographic examination, SEM and energy spectrum analysis. The results showed that the main reason was slag entrapment defect of continuous casting billet. After deformation of roughing passes, the deformation in low temperature area at the corner of intermediate billet was beyond the tolerance thermoplastic of material under the action of vertical roll side pressure, and the corner cracks were produced, which couldn′t be welded in rolling process, then the continuous shell was produced along the rolling direction, and the shell was turned over to the top and bottom of slab in the flanging process of intermediate billet. In the end the shell was distributed in the edge area of hot-rolled strip.