唐钢FTSC工艺生产SS400热板卷的轧制孔洞缺陷控制

 针对唐钢FTSC薄板坯连铸连轧线生产SS400热板卷的轧制孔洞缺陷，对连铸坯的低倍组织、铸坯温度分布和动态软压下工艺进行了研究。结果表明：铸坯存在内部横裂纹和疏松缺陷，内部裂纹产生在0扇形段，裂纹处硫元素呈正偏析；铸坯内部裂纹和疏松缺陷在后续轧制中不能够焊合，是导致轧制孔洞缺陷的直接原因。通过优化动态软压下参数，将压下终点向前提和减小0扇形段的压下量；增加二次冷却强度，提高冷却均匀性；提高钢水质量、加强设备精度管理和推进恒拉速操作，可以完全避免中碳钢SS400热轧板卷轧制孔洞缺陷的产生。

Cavity Defect Control on Hot-Rolled Strip of SS400 Steel Produced by FTSC in Tangsteel

Aiming at the cavity defects located in the coil of steel grade SS400 after hot rolling by FTSC process in Tang shan Steel Company, the microstructure and temperature distribution of the slab, and the process of dynamic soft reduction was investigated. The results show that heavy inner transverse cracks and cavity defects are found in the slab, which are the directly causes for the pore defects of the hot rolling coil. And the inner transverse cracks are generated at the segment zero, element sulfur is normal segregation in the region of cracks. Therefore, by adjusting the dynamic soft reduction rules, such as decreasing the distance between the reduction end and mould, and decreasing the reduction amount at segment zero, by increasing the secondary cooling strength to enhance the cooling uniformity, by improving the liquid steel quality and equipment accuracy and by promoting the operation of constant casting speed, the cavity defects of the hot rolling coil was solved completely.