对断裂的氢气压缩机活塞杆进行了断口宏观形貌和微观形貌、化学成分分析, 显微组织观察, 拉伸性能、冲击性能以及硬度测试, 分析了其断裂失效原因。结果表明: 氢气压缩机活塞杆为疲劳断裂; 活塞杆进行调质处理时淬火冷却速率过慢且回火温度不够高, 得到的是不均匀马氏体、珠光体和索氏体的混合组织, 而非均匀的回火索氏体, 因此综合力学性能较低, 导致过早出现疲劳断裂。

The fracture failure causes of the piston rod used in a hydrogen compressor were analyzed based on macrography, micrography and chemical composition analysis, microstructure observation, tests of tensile and impact properties and hardness. Results show that failure of the the piston rod of hydrogen compressor was due to fatigue fracture. When the piston rod proceeded thermal refining, the cooling rate in quenching was too slow and the tempering temperature wasn′t high enough, so the obtained microstructure was the mixture of heterogeneous martensite, pearlite and sorbite in stead of homogeneous sorbite. Therefore the comprehensive mechanical properties of piston rod declined and led to an early occurrence of fatigue fracture.