某厂罗茨风机在使用过程中转子轴发生断裂, 采用宏观检验、硬度测试、金相检验、扫描电镜分析、磁记忆检测等方法, 对该罗茨风机转子轴的断裂原因进行了分析。结果表明: 罗茨风机转子轴断裂性质为脆性断裂; 由于激光熔覆工艺不合理, 在熔覆层与基材间产生了微裂纹及两个较大的残余应力区域, 微裂纹在局部残余应力及外加载荷的作用下不断扩展, 最终导致了断裂的发生。

The rotor shaft of a Roots blower in a plant fractured during service. By means of macrographic inspection, hardness testing, metallographic inspection, scanning electron microscopy analysis, magnetic memory testing and so on, fracture reasons of the rotor shaft of the Roots blower were analyzed. The results show that: due to the unreasonable laser cladding technology, micro-cracks and two major residual stress regions generated between cladding layer and the substrate; micro cracks extended under the action of residual stress and applied load, which finally resulted in the fracture.