离心式压缩机油泵轴断裂的失效分析

Failure analysis on shaft fracture of centrifugal compressor's oil pump

某款油泵在使用3个月后,出现断轴的故障。本文通过对失效样品进行材料成分分析、硬度测试、金相分析,对断裂面进行电镜扫描以及对油泵轴进行有限元应力分布分析。结果表明:油泵断轴的断裂面位于退刀槽处,退刀槽由于无过渡圆角,产生应力集中;而且由于轴的热处理工艺不当,存在过多网状分布的片状铁素体,导致力学性能差,轴芯位置硬度严重偏低,最终造成油泵轴断裂。

The shaft fracture happened to one oil pump after being used for three months. The analysis on the failed samples on the material composition, the hardness test as well as the metallography are conducted. The fracture surface is scanned by the electron microscope while the finite element of the oil pump＇s shaft is analysed. The results show that the fracture surface of the oil pump is located at the back of the cutter groove. The cutter groove has no transition fillet, thus its stress is concentrated. At the same time, due to the improper heat treatment process of the shaft, there are too many network-dis-tributed flake ferrite, resulting in poor mechanical properties and shaft core with extra low hardness. All the above results in the oil pump＇s shaft fracture.