电动汽车下摆臂疲劳断裂分析  

Fatigue fracture analysis of the lower arm of electric automobile

作　　者：张彦文[1] 许竹桃[1] 张友登[1] 

机构地区：[1]武钢研究院,湖北武汉430080

出　　处：《电焊机》2015年第5期50-54,共5页Electric Welding Machine

摘　　要：电动汽车下摆臂使用一段时间便发生疲劳断裂,断裂源位于焊缝根部。为了弄清断裂原因,运用宏观观察、扫描电镜及能谱仪、光学显微镜等方法进行分析,结果表明:断裂源附近的焊缝根部存在未熔合缺陷;未熔合受力时在端部产生应力集中,导致裂纹萌生,在循环工作应力作用下裂纹不断扩展,直至贯穿整个截面而断裂失效。热影响区的马氏体组织进一步加速了疲劳扩展过程。可以通过合理布局加强筋位置,在保证强度的前提下,适当缩短加强筋长度,以及加强焊接工艺管理等措施加以解决。The electric automobile＇s lower arm fractures in several months＂ working. In order to find how it occurs,the samples are analyzed by the means of macroscopic observation,scanning electronic microscope and X-ray energy spectrometer,metallographic microscope and so on. The results show that there are incomplete fusion defects near fracture origin. The stresses concentrate at the end of incomplete fusion when lower arm works and the cracks occur because of this. The cracks are extending in the stress cycle work until the lower arm fractures. The martensite organization in the heat affected zone further accelerates the process of fatigue expansion. This can be solved by some measures,such as reasonable layout of the stiffener locations,appropriately shortening the length of the stiffener on the premise of guaranteeing strength, and reinforcing the welding process management and so on.

关 键 词：疲劳断裂 断裂源 未熔合 马氏体 

分 类 号：TG405[金属学及工艺—焊接]