机械振动辅助铝合金MIG焊接接头组织与性能研究  

Microstructure and Properties of Mechanical Vibration-Assisted MIG Welded Joint of Aluminum Alloy

作　　者：茅卫东 石铭霄 李盛良[1,2] 李敬勇 陈书锦[3] 陈九公[3] MAO Weidong;SHI Mingxiao;LI Shengliang;LI Jingyong;CHEN Shujin;CHEN Jiugong(Chery New Energy Automobile Co.,Ltd.,Wuhu 241003,China;Anhui Key Laboratory of New Energy Automobile Lightweight Technology,Wuhu 241003,China;School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003,China)

机构地区：[1]奇瑞新能源汽车股份有限公司,安徽芜湖241003 [2]新能源汽车轻量化技术安徽省重点实验室,安徽芜湖241003 [3]江苏科技大学材料科学与工程学院,江苏镇江212003

出　　处：《电焊机》2022年第10期9-14,共6页Electric Welding Machine

基　　金：安徽省科技重大专项资助项目(2019b05050006);江苏省高等学校基础科学(自然科学)研究重大项目(22KJA460011)。

摘　　要：MIG焊是新能源汽车铝合金车身的主要连接工艺,但铝合金MIG焊接存在接头软化、焊缝极易出现气孔等问题,给铝合金车身结构焊接质量管控带来了严峻挑战。为了改善铝合金MIG焊的接头质量,将机械振动作为外部激励引入到铝合金MIG焊接过程中,采用光学显微镜和扫描电子显微镜观察接头微观组织,采用电子背散射衍射仪确定焊缝和热影响区的晶粒大小,采用X射线探伤仪检测接头中的气孔数量,使用维氏硬度计测试接头显微硬度,在电子万能试验机上进行室温拉伸试验,研究振动频率对焊缝成形、气孔分布、显微组织及力学性能的影响。结果表明,机械振动能有效细化焊缝晶粒,减少焊缝气孔数量,增大熔深,提升接头强度和硬度,提高铝合金的焊接质量。并且随着振动频率增加,焊缝晶粒尺寸和气孔数量逐渐减小,熔深及接头的抗拉强度和硬度逐步增加。MIG welding is a primary joining process for car body structure of aluminum alloy involved in the electric cars,but there are some problems such as joint softening and great tendency to form pores in the weld, which brings severe challenges to the quality control of aluminum alloy car body structure welding. Acting as an external excitation, mechanical vibration was introduced into the MIG welding process of aluminum alloy to improve the quality of welded joint. The microstructure of the welded joint was observed by optical microscope and scanning electron microscope. The grain sizes of weld and heat affected zone were determined by electron backscatter diffractometer. The number of pores in the weld was detected by X-ray detector. The microhardness of joints was tested by a Vickers-type microhardness tester. The tensile test at room temperature was carried out on electronic universal testing machine to study the effect of vibration frequency on weld appearance, pore distribution, microstructure and mechanical properties. The results show that mechanical vibration can effectively refine the grains of the weld, reduce the number of pores in the weld, increase the penetration, and improve the strength and hardness of the joint. In addition, as the vibration frequency increases, the grain size of the weld and the number of pores in the weld gradually decrease, the penetration, tensile strength and hardness of the joint continuously increase.

关 键 词：机械振动 铝合金 MIG焊接 显微组织 气孔 

分 类 号：TG457.14[金属学及工艺—焊接]