含磷高强IF钢热轧轧裂的形成原因及控制

Forming reason and control of strip fracture in high strength IF steel containing phosphorus during hot-rolling process

观察了高强IF钢热轧轧裂缺陷的微观形貌及热卷拉伸试样断口情况,分析了轧裂形成原因主要始于铸坯的中心偏析造成的中部裂纹及中部缩孔等内部缺陷。按照目前现行的连铸工艺,提出改善措施为控制过热度在30℃之下以及加大轻压下量至4mm,可有效改善铸坯内部质量,减轻中心裂纹及缩孔的产生,有效避免了轧裂的产生。

The microstructure of the fracture defect in the high strength IF steel during hot-rolling process and fracture morphology of hot-strip tensile sample were observed.The main forming reason of the strip fracture was inner defects such as middle fissure and shrinkage due to center segregation of casting blank.Suggested improvement measures according to current continuous casting process was that the degree of superheat should be lower than 30℃and soft reduction amount should be improved to 4mm,which can effectively improve inner quality of the slab and alleviate the middle fissure and shrinkage defects and effectively prevent the occurrence of the fracture during hotrolling process.