针对某减速机输出轴发生早期断裂失效,采用断口观察、化学成分分析、力学性能测试、金相分析及SEM微观形貌分析等手段对其断裂原因进行了分析。结果表明:该输出轴断裂的主要原因是由其表面存在的机加工缺陷产生的应力集中以及不当的热处理工艺所引起。通过严格控制输出轴的机加工和热处理工艺可避免输出轴的断裂。 Aiming at the early failure of the output shaft of a reducer, the fracture reason was analyzed by means of fracture observation, chemical composition analysis, mechanical property test, metallographic analysis and SEM micro-morphology analysis. The results show that the main reason for the fracture of the output shaft is the stress concentration caused by machined defects on the surface and the improper heat treatment process. By strictly controlling the output shaft machining and heat treatment process to avoid the output shaft fracture.