某反应釜的自吸式搅拌轴在运行过程中发生断裂,采用宏观观察、化学成分分析、剪应力校核、金相检验、扫描电镜分析、能谱分析及有限元模拟等方法对断裂原因进行研究。结果表明:螺孔变形、角焊缝处材料敏化,以及结构上的应力集中是该搅拌轴发生疲劳断裂的主要原因。

The self-priming stirring shaft of a reactor fractured during operation. The fracture causes were studied by macroscopic observation, chemical composition analysis, shear stress check, metallographic examination, scanning electron microscope analysis, energy spectrum analysis and finite element simulation. The results show that the screw hole deformation, material sensitization at the fillet weld and stress concentration on the structure were the main reasons for fatigue fracture of the stirring shaft.