侧面碰撞车门防撞杆的失效与焊缝布置优化  

Side Impact Failure of Car Door Bumper Bar and Layout Optimization of Its Weld Seam

作　　者：薛喜才 XUE Xi-cai(Shanghai Automotive Corporation Co.,Ltd.,Passenger Vehicle Company,Shanghai 201800,China)

机构地区：[1]上海汽车集团股份有限公司乘用车公司,上海201800

出　　处：《失效分析与预防》2021年第5期314-318,326,共6页Failure Analysis and Prevention

摘　　要：介绍车型侧面碰撞试验,并对试验过程中防撞杆开裂的问题开展系列检测与分析,如外观观察、金相组织分析、断口分析以及三点弯曲试验等,最终查明零件失效的根本原因并提出整改方案。结果表明:防撞杆材料为高强度焊管,经过淬火+低温回火后材料组织敏感性较高;防撞杆在与支架进行二氧化碳保护焊接过程中受到焊接热的影响,进而导致焊管局部材料组织发生转变、力学性能遭到弱化,侧面碰撞时从薄弱区发生开裂。通过改变防撞杆与支架的焊缝布置方式,由周向焊接更改为纵向焊接,来减轻焊接热的影响,后续零件已经顺利通过碰撞试验。The side impact test of a car was introduced,and a series of detection and analysis on the cracking problem of the bumper bar during the test was carried out,such as appearance observation,metallographic structure analysis,fracture analysis and three-point bending test.Finally,the basic failure cause of the part was found out and improvement measures were put forward.The results show that the material of the bumper bar is high strength weld pipe,and the microstructure sensitivity of the material is high after quenching and low temperature tempering.In the process of carbon dioxide protection welding between the bumper bar and the support,the local microstructure of the weld pipe was transformed under the effect of welding heat,weakening the mechanical properties.Crack initiated from the weak region during side impact test.By changing the welding seam layout between the bumper bar and the support from circumferential welding to longitudinal welding,the impact of welding heat was reduced.The subsequent parts have smoothly passed the impact test.

关 键 词：防撞杆 侧面碰撞 焊管 焊缝布置 

分 类 号：U467.3[机械工程—车辆工程]