含磷高强IF钢热轧轧裂原因分析

Research of Rolling Crack of Hot Rolled P-Added High Strength IF Steel

观察了含磷高强IF钢热轧轧裂缺陷的微观形貌及热轧卷拉伸试样断口情况，分析了轧裂形成原因主要始于连铸坯的中心偏析造成的中部裂纹及中部缩孔等内部缺陷。根据现有连铸工艺条件提出了控制过热度低于30℃以及加大轻压下量至4mm等改善措施，可有效改善连铸坯内部质量，减轻中心裂纹及缩孔的产生。

The microstructure of roiling crack defect and the fracture of tensile sample of the hot rolled P-added high strength IF steel were observed. The reasons for rolling crack were analyzed, which showed that inner defects such as middle fissure and shrinkage resulting from center segregation of continuous casting slab was the main cause. According to current continuous casting process, improvement measures, including controlling the superheat to lower than 30 ~C and increasing soft reduction amount to 4 mm were put forward, which could effectively improve inner quality of the slab and reduce the middle fissure and shrinkage defects.