6061铝合金超音频脉冲MIG焊接头微观组织及力学性能  

Microstructure and mechanical properties of 6061 aluminum alloy welded joints by ultrasonic frequency pulsed MIG welding

作　　者：康金文 梁宝山 武永利 李孟孟 范霁康 KANG Jinwen;LIANG Baoshan;WU Yongli;LI Mengmeng;FAN Jikang(CRRC Datong Co.,Ltd.,Datong 037000,Shanxi pro.,China;School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,Jiangsu pro.,China)

机构地区：[1]中车大同电力机车有限公司,山西大同037000 [2]南京理工大学材料科学与工程学院,江苏南京210094

出　　处：《焊接技术》2024年第12期41-46,I0002,共7页Welding Technology

基　　金：中央高校基本科研业务费专项资金资助项目(2023303004,30922010921)。

摘　　要：针对高速列车6061铝合金车身MIG焊接一直存在气孔缺陷多发、显微组织粗大、力学性能较差等难题,提出一种超音频脉冲MIG焊接方法,以ER4043铝合金焊丝为填充材料,研究了不同超音频脉冲参数对焊接接头微观组织及力学性能的影响。研究发现:超音频脉冲电弧的引入可以减小焊缝区粗大树枝晶的尺寸,减少数量,提高等轴细晶粒所占面积,且超音频脉冲频率越高,晶粒细化效果越好;随着脉冲频率的升高,超音频脉冲MIG焊缝熔合区边缘的柱状枝晶也随之变窄、变细、弥散,并且使柱状晶数量逐渐减少;在常规脉冲MIG的基础上加入超音频脉冲电流可以同时提高焊接接头的强度和延性,频率40 kHz时,抗拉强度最高,达到250 MPa,为母材强度的88.3%,断后伸长率达到了母材的15.2%。A ultrasonic frequency pulsed MIG welding method was proposed to solve the problems of multiple porosity defects,coarse microstructure and poor mechanical properties in the MIG welding of 6061 aluminum alloy used in high speed trains.ER4043 aluminum alloy welding wire was used as the filler material,and the influence of different ultrasonic frequency pulse parameters on the microstructure and mechanical properties of the welded joint was studied.It was found that the ultrasonic frequency pulse arc could reduce the size and number of coarse dendrites in the weld zone,increase the area occupied by equiaxed fine grains,and the higher the frequency of ultrasonic pulse,the better the grain refinement effect.As the pulse frequency increased,the columnar dendrites at the edge of the fusion zone of the ultrasonic frequency pulsed MIG weld also became narrower,finer,and more dispersed,and the number of columnar dendrites gradually decreased.On the basis of conventional pulsed MIG,adding ultrasonic frequency pulse current could simultaneously improve the strength and ductility of welded joints.At the frequency of 40 kHz,the tensile strength was highest,reaching 250 MPa,which was 88.3%of the base metal strength,and the elongation rate reached 15.2%.

关 键 词：6061铝合金 超音频脉冲 MIG焊 微观组织 力学性能 

分 类 号：TG457[金属学及工艺—焊接]