【摘要】 4Cr13模具钢铸锭凝固过程易形成缩孔、裂纹和宏观偏析等缺陷，严重影响产品品质和材料收得率。采用原位熔化冷却法研究了缓冷条件下脉冲磁致振荡（PMO）处理对4Cr13钢铸锭凝固组织和元素偏析的影响。结果发现，未经PMO处理的铸锭为全柱状晶组织，出现严重的中心缩孔和裂纹，且元素偏析严重。但PMO处理铸锭的中心缩孔和裂纹完全消失，且等轴晶区面积达到铸锭横截面积的50%以上；铸锭心部C含量得到有效控制，PMO处理后4Cr13的心部C含量降幅为12.94%，且C和Si、Cr元素含量波动明显减小。PMO处理显著细化4Cr13钢的枝晶组织，一次枝晶长度减小了约70%。更多还原

【Abstract】 The solidification process of 4Cr13 mold steel is prone to form defects such as shrinkage holes, cracks and macroscopic segregation, which seriously affects the product quality and material yield. The influence of PMO treatment on the solidification microstructure and elemental segregation in 4Cr13 steel ingots under slow cooling conditions was investigated by in-situ melt cooling method. The results reveal that the ingot without PMO treatment iexhibits whole columnar crystal structure with serious center shrinkage and cracks as well as serious elemental segregation.After PMO treatment, shrinkage and cracks in ingot center completely disappear, and the area of equiaxial crystal area reaches more than 50% of the ingot cross-sectional area. C content in ingot core is effectively controlled, which is decreased by 12.94% in the core of 4Cr13 after PMO treatment. Meanwhile, fluctuations of C and alloying elements Si,Cr content are significantly reduced. PMO treatment can significantly refine the dendritic microstructure of 4Cr13steel, and the length of the primary dendrites is reduced by about 70%.更多还原