某厂生产的离心压缩机叶轮部件在车削加工过程中表面发现宏观可见裂纹,结合原材料25Cr2Ni3Mo的入厂状态以及锻造和热处理工艺,采用金相观察、扫描电镜和电子探针等实验对叶轮表面裂纹的产生原因进行了分析。结果表明,裂纹边缘有氧化脱碳层分布,裂纹产生于锻造过程中,裂纹的形成主要与原材料中的氧化物夹杂有关。
The crack was found on the surface of a impeller in the forging process.Considering the forging and heat treatment processes,with the methods of optical metallographic,SEM and EPMA,the mechanism of the crack was studied.The oxidation and decarbonization layer are near the edge of crack and it can prove that the crack is caused by inclusion and occurs in forging process.