汽車后扭力梁開裂問題分析

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Abstract：The failureanalysis was conducted onthe cracked rear torsion beam ofacertain vehicle model after fatigue durability test byusing direct-reading spectrometer，hardness tester，scanning electron microscope and metallographic microscope.The chemical composition and hardness meet the material standards and technical requirements of the drawings.The results offracture and metallographic inspection show that the failure mode of the rear torsion beam is stress corrosion cracking originating from the inner wall.The main reason is that the poor anticorrosion treatment of the iner wallof the rear torsion beamcauses corrosion，resulting in stress corrosion cracking and expansion of the rear torsion beam with high-strength tisse sensitivity under the tensile stress of the fatigue strength test.The fatigue durabilitytest was carriedout with the rear torsion beam assembly without corrosion on the inner wall， and no cracking problem was found.

Keywords： rear torsion beam; fatigue endurance test; corrosion pit; stress corrosion cracking

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扭力梁式后懸架系統(tǒng)，具有結構簡單、占用空間小、成本較低，以及裝配維修便利等優(yōu)點，在A/A0級乘用車上廣泛應用[1，2]。（剩余3319字）