焊接热输入量对AZ31B镁合金焊接接头组织和性能的影响

Effect of welding heat input on the microstructure and properties of welding joints of AZ31B magnesium alloy

应用自动焊接方法研究不同的焊接热输入量对AZ31B镁合金的焊接接头性能的影响。选用WE WELDING33M焊丝,焊接热输入量分别为0.9 kJ/mm、1.1 kJ/mm、1.4 kJ/mm、1.7kJ/mm。结果表明:随着焊接热输入量的增加,焊缝晶粒随之变大,接头拉伸力学性能随之下降;在焊接热输入量为0.9 kJ/mm时,接头抗拉强度达到最大值215.5 N/mm2,约为母材的90%;当焊接热输入量为1.70 kJ/mm时,力学性能大幅下滑,抗拉强度仅为130.6 N/mm2。考虑到热输入量增加有利于提高焊接效率,结合工程实际及生产成本,建议焊接热输入量选择1.4k J/mm,此时焊接接头抗拉强度可达到180 N/mm2左右。

The welding properties of AZ31B magnesium alloy under different welding heat inputs were studied by the automatic welding method.WE WELDING33 M welding wire was selected and the welding heat inputs were set as 0.9 kJ/mm,1.1 kJ/mm,1.4 kJ/mm and 1.7 kJ/mm,respectively.Test results show that as the welding heat input increases,the grain size of weld becomes larger and the tensile mechanical property of joints decreases.When the welding heat input is 0.9 kJ/mm,the maximum tensile strength of joints is reached as 215.5 N/mm^2,about 90%of the tensile strength of the base material.When the welding heat input is 1.70 kJ/mm,the mechanical property declines significantly,and the tensile strength is only 130.6 N/mm^2.Considering the increase of welding heat input is beneficial to improving welding efficiency,combined with the actual engineering and production costs,it is proposed to select 1.4 kJ/mm as the welding heat in p u t,and then the tensile strength of welded joints can reach about 180 N/mm^2.