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一、前言近几年来,我国很多电站陆续发现汽轮机转子的末儿级叶轮在键槽根部出现裂纹,据不完全统计,到目前为止,共二十七起(附录1)。叶轮键槽如有严重的裂纹将造成危害性事故。因此,对已发现裂纹的叶轮都要采取相应措施。例如调换新叶轮或将键槽挖深,除去裂纹,然后加套或补焊来进行修复。但是这些措施都要造成电厂停机,严重影响生产。为此有必要应用断裂力学对含裂纹的叶轮进行安全分析,查明裂纹生成原因,
I. INTRODUCTION In recent years, many power plants in our country have successively discovered that the last-stage impellers of steam turbine rotors have cracks in the root of keyways. According to incomplete statistics, so far, a total of 27 cases have been found (Appendix 1). Impeller keyway if there is a serious crack will cause harmful accidents. Therefore, the crack has been found on the impeller to take appropriate measures. Such as exchanging a new impeller or digging the keyway to remove the crack, and then add or repair welding to repair. However, all these measures will cause the shutdown of the power plant and seriously affect the production. Therefore, it is necessary to apply fracture mechanics to analyze the cracked impellers, to find out the causes of crack formation,