某压缩机活塞杆使用约三个月发生断裂。利用化学分析、宏观断口分析、显微组织和显微硬度分析、扫描电镜及能谱分析等方法进行了分析。结果表明,该活塞杆在断裂面附近有周向分布的磨削裂纹;磨削裂纹在活塞杆运行过程中受交变应力而扩展;活塞杆内部有较多聚集分布的柱状AlN非金属夹杂物并且金相组织较粗大,降低了材料强度同时也使得裂纹易于扩展。 Some compressor piston rod fracture occurred about three months. The chemical analysis, macroscopic fracture analysis, microstructure and microhardness analysis, scanning electron microscopy and energy spectrum analysis methods were analyzed. The results show that the piston rod has a circumferential distribution of grinding cracks near the fracture surface. The grinding crack expands by alternating stress during the operation of the piston rod. There is more columnar AlN non-metallic inclusions And the relatively coarse metallurgical structure, reducing the strength of the material also allows easy expansion of the crack.