引风机主轴断裂原因分析

Analysis on Fracture of Draft Fan Shaft

某企业于2014年生产的材质为42CrMo的引风机主轴在运行过程中发生断裂,直接影响电站风机的运行。结合主轴使用工况,对主轴断口进行了宏观和微观形貌观察,对主轴材料进行了化学成分分析、微观组织观察、硬度以及拉伸性能试验。结果表明:引风机主轴组织分布不均匀且存在明显的夹杂物,使得主轴力学性能不均匀;同时在工作载荷下,轴肩处圆弧过渡处明显的车削加工槽会形成严重的应力集中,是造成主轴疲劳断裂的原因。

The shaft of a 42CrMo fan produced in 2014 broke during operation, which directly affected the operation of the fan. Combined with the working conditions of the spindle, the macro and micro morphology of the spindle fracture was observed, and the chemical composition analysis, microstructure observation, hardness and tensile properties test of the spindle material were carried out. The results show that the mechanical properties of the shaft are uneven due to the inhomogeneous distribution of the shaft structure. At the same time, there are obvious turning grooves in the arc transition of the shaft shoulder, which form serious stress concentration when the spindle is running, resulting in the fatigue fracture.