在电厂机组启停和运行参数变化时，汽轮机低压转子末级叶片易受到交变应力作用而发生开裂，影响汽轮机的安全运行。对某汽轮机发生开裂的叶片进行了金相检验、硬度测试、断口分析和能谱分析，以确定叶片开裂的原因。结果表明：该开裂叶片材质状态正常，叶片开裂的原因为腐蚀疲劳，是由腐蚀环境和交变应力的共同作用导致的。

Cracking often happened to last-stage blades of low-pressure turbine rotors due to the alternating stress during the process of starting, stopping and changing of working parameters in power plants, which threatened the safe operation of turbines. The cracking turbine blade was analyzed to make sure the cracking reasons by metallographic examination, hardness testing, fracture analysis and energy spectrum analysis. The results show that:the material of the cracking blade was qualified, and the cracking reason was the corrosion fatigue caused by the combined action of corrosion environment and alternating stress.