汽车车身螺栓套断裂失效分析与改进

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中图分类号：U463.89 文献标志码：B DOI：10.19710/J.cnki.1003-8817.20250109

Abstract：Based on theanalysis of the fracture surfaceand energy spectrum of the fractured bolt sleeve in the roadtest，itisdeterminedthat thefracture failuremodeisdelayedcracking.Furthermore，from theaspectsof metallgraphyandhardnessitisfound thatimproper weldingprocess ledtotheformationofmediumcarbon martensiteintheboltsleeve，and high hardness is themainreason fordelayed cracking.Theproblemof highhardness oftheboltsleeveissolved byimproving the welding technologyofthebolt sleeve.Theimprovedbolt sleeveis subjected to metalographicand hardness testing again.Themartensitecontentand hardnessof the improvedbolt sleevearereduced toareasonable range.The problem of delayed cracking of the bolt sleeve is efectivelycontrolled.

Keywords：Boltsleeve，Welding，Delayedcracking，Martensite

1前言

汽车螺栓套是悬架与车身的关键连接点，需满足连接的刚度、强度、焊接性能等特殊性能。（剩余4705字）