Analysis on Fracture Reasons of the Clamp Rod Bolt Used for High-Speed Rail Turnout

The clamp rod bolt of 1Cr17Ni2 stainless steel used for high-speed rail turnout fractured when the bolt was used for about six years. The fracture reasons were analyzed by methods of macroscopic examination, chemical composition analysis, tensile test, hardness testing and so on. The results show that:the main fracture reason of the bolt was that the transition fillet radius of the fracture position didn't meet the technical requirement, and it intensified the stress concentration of the position and induced fatigue cracks under the external force; when the clamp rod bolt was in a state of loose, the train at high speed would cause the bolt to create a inertia force in the opposite direction of the moving running, which led to the fatigue fracture of the bolt on its weak position.