大型门式起重机因变速机轴断裂致使起吊物料下坠而造成安全生产事故。通过宏观和微观分析方法对变速机轴断裂原因进行了分析,结果表明,变速机轴在长期服役运行过程中,因局部疲劳开裂并扩展而引发了瞬间脆性断裂,其断裂与轴的制造质量不高和长达50a(年)的服役时间有关。

The drop of lifted body with a production safety accident was caused by the fracture of the variable-speed motor shaft of the large-sized gantry crane. The fracture causes of the variable-speed motor shaft were analyzed by using macroscopic-and microscopic analysis methods. The results showed that the immediate brittle fracture was triggered by local fatigue cracking and extending of variable-speed motor shaft in long-duration operation,and the fracture of the shaft was related to the low manufacturing quality and about fifty years active time.