高炉煤气能量回收透平叶片失效的原因

Failure Reason of the Blade of Top Gas Energy Recovery Turbine

摘要: 某湿式高炉煤气能量回收透平（TRT）机组运行3 a后，发现其一级和二级动叶片叶根出现裂纹，通过宏观形貌观察、化学成分分析、拉伸性能测试、微观形貌观察等对叶片进行了失效分析，探讨了裂纹产生的原因。结果表明：叶片上的裂纹属于典型的腐蚀疲劳开裂，裂纹位于叶根第一榫齿中间部位；裂纹在叶根与主轴榫槽的接触面所产生的腐蚀坑处萌生，在复杂交变应力的作用下，裂纹进一步扩展，最终导致机组的异常振动和停机。

Abstract: Cracks were found in the first and second stage rotor blade root section of a wet-typed top gas energy recovery turbine (TRT) after operation for 3 a. In order to investigate the cause for cracks, the failure analysis of the blade was performed by macroscopic morphology observation, chemical composition analysis, tensile property test and microscopic morphology observation. The results show that the blade failure was a typical corrosion fatigue damage. The cracks were located in the middle of the first tenon of the blade root. The cracks were initiated from corrosion pits on the contact surface of blade root and shaft groove. Under the effect of complex alternating stress, cracks propagated further, which eventually led to the abnormal vibration and the shut-down of the TRT.