某电厂次次末级叶片断裂原因分析

Fracture analysis of the second last stage blade of a power station

某电厂检修时发现次次末级叶片在叶根第一齿处出现裂纹,通过断口特征分析、材质理化检验、硬度及受力分析等对叶片裂纹产生原因进行分析。最终得出结论:裂纹源萌生于叶根齿面圆弧过渡区的应力集中区,机械打磨形成的缺口是形成疲劳裂纹的主要原因。

When a power plant overhauling,it found that the second last stage blade cracked in the first teeth of the blade root. Through the characteristics of fracture,material physical and chemical inspection,hardness test and force analysis,the results show that the source of crack initiated in the area of stress concentration of tooth surface arc transitional area in the blade root. And the main reason of the formation of fatigue crack was the gap that formed by mechanical grinding.