M16吊耳螺栓断裂失效分析

Failure Analysis of M16 Lifting Eyebolt

吊耳螺栓在某工厂起吊惰轮过程中突然发生断裂.利用体视显微镜、金相显微镜、扫描电子显微镜、直读光谱仪和布氏硬度计等手段,对发生断裂的吊耳螺钉的断口宏观形貌、微观形貌、组织、化学成分和硬度进行分析.通过现场调查和力学分析对失效原因进行了分析验证.结果表明:吊耳螺栓为典型的正火组织,硬度及化学成分均符合设计要求;零件断裂模式为过载断裂;断裂主要原因与吊耳螺栓使用不当有关,断裂处的应力集中也是引起断裂的原因之一.

The lifting eyebolt broke suddenly when lifting the idler wheel in the factory.The fracture morphology,microstructure,chemical composition and hardness of the eyebolt were analyzed by stereomicroscope,metallographic microscope,scanning electron microscope,direct reading spectrometer and brinell hardenss tester.The failure reason was also analyzed and verified by field investigation and mechanical analysis.The results indicate that microstructure,chemical composition and hardness of the lifting eyebolt meet the design requirements;the fracture mode of the eyebolt is overload fracture;the primary reason of the failure is improper application and stress concentration at the crack is one reason of the fracture.