复合助焊剂对AZ31镁合金TIG焊接头组织与性能的影响

Effect of compound flux on microstructure and properties of TIG welded joints of AZ31 magnesium alloy

采用钨极氩弧焊(TIG)方法对AZ31镁合金进行焊接实验,研究新型复合助焊剂对AZ31镁合金焊接接头组织的性能的影响,探索优化镁合金焊接质量的方法和工艺。结果表明:实验所使用的新型助焊剂可通过"电弧收缩"和"表面张力"复合效应来优化焊接热循环;部分助焊剂以原子态进入电弧区域作用于焊接电弧,而熔入熔池的助焊剂则是通过改变熔池表面张力来加大AZ31镁合金焊接熔深,减小熔宽;助焊剂增加熔合区晶粒形核能力,细化该区晶粒,使第二相呈网状分布,提高AZ31镁合金焊接接头的综合力学性能。

GTAW （TIG） method was applied to the AZ31 magnesium alloy’s welding and the effects of new compound flux on the microstructure and properties of TIG welding of AZ31 magnesium alloy were investigated to develop new method and technology for promoting the quality of magnesium alloy welding. The results show that the new compound flux can optimize the welding thermal cycle through combining the arc-contraction effect and surface tension effect. Part of the flux runs into the arc region and acts on the welding arc. The melting flux into the pool increases the welding penetration of AZ31 magnesium and reduces the melting width by changing the surface tension of the molten pool significantly. The new flux increases fusion zone grain nucleation capacity, refines the grain, and makes the second phase distribute as network, which improves the mechanical properties of welded joints of AZ31 magnesium alloy.