针对电力行业中某发电机密封油系统灰铸铁安全阀在安装过程中断裂失效问题，对其进行了宏观分析、拉伸试验、金相检验、断口微观分析等检验，分析了其断裂原因。结果表明：该安全阀断裂模式为典型的灰铸铁脆性断裂；安全阀强度偏低和安装工艺不当，是导致其发生脆性断裂的主要原因。最后提出了预防措施。

The gray iron safety valve of a generator sealing oil system in electric power industry fractured during installation, and series of test such as macro analysis, tensile test, metallographic examination and fracture micro analysis were done to the failure safety valve to find out the fracture reasons. The results show that the fracture of the safety valve was typical brittle fracture of gray iron. The low strength of the safety valve and improper installation process were main reasons for the brittle fracture. Finally, preventive measures were put forward.