热输入对铝合金双脉冲MIG焊接头性能的影响

Effect of line energy on properties of aluminum alloy joints in double pulsed MIG welding

采用双脉冲MIG焊技术对6061-T6铝合金进行对接连接,研究热输入对焊接过程、接头显微组织结构及力学性能的影响.结果表明,在一定热输入范围内,双脉冲MIG焊焊接过程稳定,飞溅极少,焊缝呈现为美观的鱼鳞纹.热输入较小时,焊接接头存在明显的未熔合和气孔缺陷,造成抗拉强度较低.随着热输入的增加,焊接接头的热影响区宽度和熔合区晶粒尺寸逐渐增大,未熔合和气孔缺陷减少,抗拉强度显著提高.

1060-T6 aluminum alloy butt joints were obtained by double pulsed MIG welding technique. Effcet of line energy on welding process,the microstructures and mechanical properties of the joints were investigated. The results showed that the welding process of double pulsed MIG welding was stable with little spatter,and the weld appeared as beautiful fish scale,within a certain range of line energy. For lower line energy,the tensile strength of joint was lower because of incomplete fusion and gas pores. With an increase in line energy,the width of the heat-aected zone increased and grains in the fusion zone coarsened. Moreover,incomplete fusion and gas pores were gradually decreased,which was obviously improved the tensile strength of joint.