水轮机主轴断裂原因分析

Cracking Cause Analysis for Main Shaft of Hydraulic Turbine

本文采用金相分析、光谱分析、SEM分析和ANSYS有限元分析等手段对水轮机主轴的裂纹产生原因进行了分析。分析结果表明,水轮机主轴上安装的抗磨环止口底端恰好处在熔合线上,该位置应力集中,且存在导致材料综合性能恶化的魏氏组织,运行时在交变载荷作用下萌生裂纹并不断扩展,导致疲劳开裂。

The causes of cracks in hydro-turbine main shaft were analyzed by metallographic examination, spectral analysis, SEM and ANSYS. Results indicated that the bottom of wear ring spigot installed in hydro-turbine main shaft was exactly on fusion line, where the stress concentrated and Widmannstatten structure degraded the combination property of the material. Then cracks grew and expanded under the alternative load in operation. Finally fatigue cracking occurred.