斗式提升机输送链销轴断裂的分析

通过化学成分、显微组织和裂纹、断口特征的分析以及应力强度校核,对一台输送水泥用斗式提升机输送链销轴的断裂原因进行了综合分析。分析结果显示:失效销轴表面的最大弯曲应力偏大,并且在淬火期间失效销轴会产生微裂纹,在交变应力载荷作用下,销轴表面发生疲劳损伤并最终发生疲劳断裂。建议严格遵照热处理工艺条件操作,避免产生淬火裂纹;通过改造销轴结构或减小工作载荷,降低表面的最大弯曲应力。

Fracture Analysis on Pins of Hoist Chains of a Bucket Elevator

The fracture on some pins of hoist chains in a bucket elevator used to transport cement was analyzed.Stress intensity of the pins was calculated and a comprehensive research on composition,microstructure,cracks and fracture surfaces was conducted.The research showed that the maximal bending stress of the pin's surface was larger than expected and some micro cracks were generated during the quenching,which resulted in fatigue damnification on the surfaces of the pins and fracturing finally.It is suggested to strictly carry out the heat treatment according to the process's request to avoid the micro cracks' generation and change the structure of the pin or reduce the working load to diminish the surface's bending stress.