低压转子叶片叉型叶根销钉开裂原因  

Cause of Pin Fracture for Low Pressure Rotor Blade Fork-Type Blade Root

作　　者：邓辉 吴文生 吴旭良 袁红玉 谢照增 DENG Hui;WU Wensheng;WU Xuliang;YUAN Hongyu;XIE Zhaozeng(Central South Electric Power Test Research Institute,China Datang Corporation Science and Technology Research Institute,Zhengzhou 450000,China;State Grid Henan Skills Training Center,Zhengzhou 450000,China;Datang Sanmenxia Electric Power Co.,Ltd.,Sanmenxia 472001,China)

机构地区：[1]中国大唐集团科学技术研究院有限公司,中南电力试验研究院,郑州450000 [2]国网河南省电力公司技能培训中心,郑州450000 [3]大唐三门峡电力有限责任公司,三门峡472001

出　　处：《机械工程材料》2022年第12期91-97,共7页Materials For Mechanical Engineering

摘　　要：某滨海电厂660 MW超超临界机中A、B低压转子末二级叶片叉型叶根销钉发生开裂,通过宏、微观形貌观察、化学成分分析、显微组织观察及力学性能测试等方法分析了销钉的开裂原因。结果表明:销钉发生了应力腐蚀开裂。开裂销钉显微组织不均匀,且存在粗晶,其应力腐蚀敏感性较大;销钉孔内存在腐蚀介质,导致销钉表面形成腐蚀坑。在汽轮机高速转动过程中,销钉承受由叶片离心力引起的弯曲应力,在腐蚀坑处萌生微裂纹,发生应力腐蚀开裂。In a 660 MW ultra-supercritical machine of a coastal power plant, cracking occurred at the end of the secondary blade fork-type blade root pins of the A and B low-pressure rotors, and the cracking causes of the pins were studied by macro/micromorphology observation, chemical composition analysis, microstructure observation and mechanical property tests. The results show that stress corrosion cracking occurred in the pin. The microstructure of cracking pin steel was uneven, and macroscopic coarse grains existed. The stress corrosion sensitivity of the material was higher. Corrosive media existed in the pin hole, which caused corrosion pits forming on the surface of the pin. The corrosion products contained chlorine, sulfur and other elements. In the process of high-speed rotation of the steam turbine, the pin bore the bending stress caused by the centrifugal force of the blades, and microcracks germinated at the corrosion pit. Stress corrosion cracking occurred.

关 键 词：叉形叶根 销钉 腐蚀点坑 弯曲应力 应力腐蚀 

分 类 号：TG172.3[金属学及工艺—金属表面处理]