Failure Analysis of Fatigue Fracture of Piston Rod of Automobile Shock Absorber
Fatigue fracture failure of the piston rod can reduce the smoothness of vehicle operation and seriously affect the safety of vehicle driving.Therefore,it is crucial to analyze the fatigue fracture failure of the piston rod of automotive shock absorber.The chemical composition of the shock absorber piston rod specimen is analyzed using a spectrometer,and the roughness of the piston rod surface is detected through a microscope.The fatigue fracture morphology of the piston rod of an automotive shock absorber was analyzed macroscopically,microscopically,and section metallographically.The microhardness,residual stress,and gas hy-drogen content of the piston rod were measured.By observing the macroscopic morphology,it was found that the specimen had a certain characteristic of brittle cracking.The energy spectrum of microscopic analysis indicates that the content of Cr and Fe ele-ments in the specimen is high,resulting in a large surface brittleness of the specimen,and secondary cracks appear in the micro-scopic state.The section metallographic structure of the test piece has no obvious defects,and the microhardness of the main areas meets the requirements.Both have a small impact on fatigue fracture.The residual stress generated by the specimen during the ini-tial stage of quenching is relatively high,and the hydrogen content of the gas near the surface is significantly higher than that at the center.Therefore,the fatigue fracture of the piston rod of the automotive shock absorber is mainly caused by the large surface brittleness,high hydrogen content,and quenching cracks of the piston rod.
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