轨道交通车辆用5083铝合金单边角接接头的疲劳性能研究  

Study on Fatigue Properties of Single Side Corner Joint of 5083 Aluminum Aloy for Rail Transit Vehicle

作　　者：阚晓阳 胡悦兵 张世欣 李可 崔云龙 邱文政 KAN Xiaoyang;HU Yuebing;ZHANG Shixin;LI Ke;CUI Yunlong;QIU Wenzheng(CRRC Qingdao Sifang Co.,Ltd.,Qingdao 266111,China;Qingdao Qingte Casting Co.,Ltd.,Qingdao 266000,China)

机构地区：[1]中车青岛四方机车车辆股份有限公司,山东青岛266111 [2]青岛青特铸造有限公司,山东青岛266000

出　　处：《电焊机》2024年第5期60-64,116,共6页Electric Welding Machine

基　　金：山东省重点研发计划(重大科技创新工程)(2021ZDPT02)。

摘　　要：针对轨道交通车辆常用4 mm厚5083铝合金板材单边角接焊接接头展开疲劳性能研究,求得其单边角接焊接接头的S-N曲线及条件疲劳极限。采用金相显微镜、扫描电镜观察接头微观组织和疲劳断口,分析了其疲劳断裂机理。研究结果表明,5083铝合金角焊缝焊接接头微观组织均匀,无微裂纹。焊缝中心硬度最低,硬度值随焊缝中心距离增大而增大,到达母材后硬度值趋于稳定;单边角接接头立板与底板间的抗拉强度仅为110 MPa,远低于母材的324.5 MPa;在加载107条件下,中值疲劳极限为7.33 MPa,仅为母材强度的2.25%,说明沿立板方向承受交变载荷时疲劳性能较差;疲劳裂纹萌生于焊缝根部,由于焊缝内部存在气孔等缺陷,导致疲劳断口存在多个裂纹源。综上,设计5083铝合金单边角接接头时,立板不应承受交变载荷。The fatigue properties of commonly used 4 mm thick 5083 aluminum alloy plate single side corner welded joints for rail transit vehicles were studied,and their S-N curves and conditional fatigue limits were obtained.Metallographic mi‐croscope and scanning electron microscope were used to observe the microstructure and fatigue fracture of the joints,and the fatigue fracture mechanism was analyzed.The results show that the microstructure of 5083 aluminum alloy fillet weld joints is uniform and there are no microcracks.The hardness at the weld center is the lowest,and it increases with the in‐crease of the distance from the weld center,and tends to be stable after reaching the base metal;the tensile strength between the vertical plate and the bottom plate of the single side corner joint is only 110 MPa,far lower than the 324.5 MPa of the base metal;under 107 cycles of loading,the median fatigue limit is 7.33 MPa,which is only 2.25%of the base metal strength,indicating that the fatigue performance is poor when the alternating load is applied along the vertical plate direc‐tion;fatigue cracks originate from the root of the weld,and there are multiple crack sources in the fatigue fracture due to the presence of pores and other defects in the weld;In summary,when designing single-sided fillet welded joints for 5083 al-alloy,the vertical plate should not be subjected to alternating loads.

关 键 词：5083铝合金 角接接头 疲劳性能 疲劳裂纹 交变载荷 

分 类 号：TG405[金属学及工艺—焊接]