水轮机不锈钢叶片失效分析

Analysis of the Hydraulic Turbine Stainless Blade Failure

某电站水轮机检修中发现ZG06Cr13Ni4Mo叶片泄水边开裂严重,通过截取叶片开裂部位,对其进行化学成份、力学及工艺性能、宏观断口、显微组织、能谱检测分析,探讨该叶片失效的原因。多点位金相检测、多方位检测分析后的结果表明:叶片化学成分符合水轮机质量文件相关标准规定,但铸造时存在缩孔、缩松及微裂纹等铸造缺陷,该铸造缺陷在服役过程中产生疲劳扩展导致早期疲劳开裂。本文提供了一个实际生产运行中马氏体不锈钢叶片失效分析典型案例,为改善叶片的生产制造工艺提供了依据。

Serious crack was found on the running side of ZG06 Cr13 Ni4 Mo blade during hydraulic turbine maintenance in a hydropower station.And reasons for the blade failure were discussed by chemical analysis,mechanical properties tests,macro fracture observation,microstructure exam and energy spectrum detection of the cracking zone.And results of multi-point metallographic and multi-directional examinations show that the chemical composition of the blade complies with the standards on the turbine quality;however,there are some casting defects such as shrinkage cavity,porosity and micro-cracks during the blade casting process,and the fatigue growth of casting defects leads to early fatigue crack in service.This paper provides a typical case of failure analysis of martensitic stainless steel blade in actual production,which guides blade production improvement.