45钢连铸坯在生产中易出现铸坯的内部角裂缺陷。通过低倍试验、金相法和探针能谱分析,对缺陷作了分析。基于ANSYS对结晶器凝固过程进行温度场模拟得出,缺陷萌生于结晶器内,根本原因是铸坯在结晶器中凝固传热不均导致铸坯偏角区出现热节区效应,从而诱导产生热应力作用于凝固前沿致使沿柱状晶晶间铁素体开裂。通过重新设定结晶器铜管圆角半径和优化工艺,最终避免了内部角裂。 45 steel slab in the production of slab prone to the internal corner crack defects. Through the low magnification test, the metallographic method and the probe energy spectrum analysis, the defect was analyzed. Based on the ANSYS simulation of the solidification process of the mold temperature field, the defects originated in the mold. The fundamental reason is that the uneven heat transfer in the mold caused by uneven solidification heat transfer in the mold resulted in the occurrence of hot zone effect The thermal stress acting on the solidification front causes the ferrite to crack along the columnar crystal. By re-setting the corner radius of the mold copper tube and optimizing the process, internal corner cracks are eventually avoided.