直流双脉冲MIG焊对5A06铝合金焊缝组织和性能的影响

Effects of DC double-pulse MIG welding on the microstructure and properties of 5A06 aluminum alloy weld

针对5A06铝合金薄板采用传统TIG和MIG焊接工艺时出现焊接效率低、接头性能难以满足使用要求的问题,采用直流双脉冲MIG焊对5A06铝合金平板试样进行焊接试验。利用拉伸试验机、扫描电子显微镜和光学显微镜等实验设备研究直流双脉冲MIG焊工艺对5A06铝合金焊接接头微观组织和力学性能的影响。结果表明:当送丝速度为5 m/min、焊接速度为50 cm/min,脉冲频率为3 Hz、气体流量为25 L/min、焊丝干伸长为12 mm时,获得了美观的鱼鳞纹焊缝表面,焊缝区为大量细小的等轴晶组织,而且焊缝横截面气孔较少。焊接接头具有较好的抗拉性能,焊接强度系数达到90%以上。

5A06 aluminum alloy sheet welding with traditional TIG and MIG welding technology is usually inefficient and results in poor mechanical performance as well as cannot meet requirements.For this critical problem,the DC double pulse MIG welding experiments of 5A06 aluminum alloy sheets were carried out.The effects of DC double pulse MIG welding technology on the microstructure and mechanical properties of the welded joints were investigated by optical microscopy,scanning electron microscopy and tensile testing machine.The results show that when the wire feed speed is 5 m/min,welding speed is 50 cm/min,pulse frequency is 3 Hz,wire extension is 12 mm,and protective gas is high purity Ar gas with a flow rate of 25 L/min,the beautiful weld surface with fish scale figure are obtained,there is a large amount of the fine equiaxed grain in weld zone and the gas pores in the weld cross section reduce.The welded joint has good tensile property,and tensile strength of the welded joint is above 90%of the base metal.