摩托车变档轴断裂原因分析

Analysis on Fracture of Gear-shift Shaft of Motorcycles

对断裂的摩托车变档轴进行宏观、金相、化学及断口分析。结果表明变档轴由于调质处理不当致使基体中分布块状及网状分布的铁素体,导致变档轴的韧性及强度下降,在过载扭力的作用下发生扭转断裂。

Analysis on macro, metallography, chemistry and fracture appearance were carried out on broken gear - shift shaft in motorbike. The results show that blocks and network of ferrite existed in the base of gear - shift shaft due to improper quenching - and - tempering. It reduces the toughness and intensity of the shaft, that leaded to the torsion fracture of gear - shift shaft under over - torsion stress.