电流对7075-T6铝合金双丝脉冲冷金属过渡焊接接头组织和力学性能的影响  

Effect of wire current on microstructure and properties of 7075-T6 aluminum alloy joint welded by double-wire pulsed cold metal transition method

作　　者：张泽桦 李小强[1] 朱德智[1] 屈盛官[1] 王学程 ZHANG Zehua;LI Xiaoqiang;ZHU Dezhi;QU Shengguan;WANG Xuecheng(National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]华南理工大学,国家金属材料近净成形工程技术研究中心,广州510641

出　　处：《焊接学报》2022年第11期68-77,I0006,I0007,共12页Transactions of The China Welding Institution

基　　金：佛山市核心技术攻关项目(1920001000412)。

摘　　要：为提高7075-T6铝合金熔化焊接接头性能,提出了一种双丝脉冲冷金属过渡(DW-CMTP)焊接方法,并研究了双丝平均电流大小对6 mm厚7075-T6铝合金对接接头组织和力学性能的影响.结果表明,通过调控主、从丝电流可实现DW-CMTP焊接过程无明显飞溅且焊后接头成形效果良好;增加主、从丝平均电流分别能够促进熔深和熔宽;提高主丝平均电流可增大气泡上浮力,提高从丝平均电流则可加强熔池流动,以致均促进了焊缝中气体逸出,且从丝平均电流的增大对气孔降低效果更为显著;接头强度随主丝平均电流增大呈现先增加后降低的趋势,随从丝平均电流的增大则呈现先降低后增加的趋势,焊接接头最大强度达到389 MPa,为母材强度的70.8%.In order to improve the performance of the fusion welded joint of 7075-T6 aluminum alloy, a double-wire pulsed cold metal transition(DW-CMTP) welding method was proposed. The effects of the average currents of double wires on the microstructure and mechanical properties of the butt joints of 7075-T6 aluminum alloy plates in 6mm thickness were studied. The results showed that in the DW-CMTP process no obvious spattering appeared and the joint was shaped very well by adjusting the leading and trailing wire currents. Both the weld penetration depth and the weld width enlarged with the increases of the average leading and trailing wire currents respectively. Increasing either the average leading or trailing wire current enlarged the bubble’s buoyant force and fostered the flow of the molten pool. The trailing wire current had a more significant effect on the reduction of porosity in the weld seam. The tensile strength of the joint increased first and then decreased with the average leading wire current increasing,while the strength decreased first and then increased with the average trailing wire current. The maximum joint strength reached 389 MPa, which was 70.8% of that of the base metal.

关 键 词：7075铝合金 双丝脉冲冷金属过渡焊 显微组织 力学性能 气孔 

分 类 号：TG442[金属学及工艺—焊接]