ZL205A铝合金MIG焊接接头的组织与性能研究

Study on Microstructures and Properties of MIG Welded Joint of ZL205A Aluminum Alloy

研究了ZL205A铸造铝合金金属极惰性气体保护焊焊接接头的力学性能和显微组织。结果表明,ZL205A铝合金焊接性能较好,焊接过程为亚射流过渡形式,可以得到成形良好无缺陷的焊接接头。焊接接头的焊缝区为树枝状铸造组织,熔合区靠近焊缝一侧为柱状晶,靠近热影响区一侧为细小的等轴晶组织,热影响区由于受焊接热循环作用晶粒变粗大。焊缝区的冲击韧度较高,是热影响区和母材冲击韧度的2倍。焊接接头的硬度分布较为均匀。

The microstructure and properties of the welded joint of ZL205A casting aluminum alloy were studied. The results show that the alloy has good weldability, and the meso-spray transfer can appear in welding process to obtain good welding joint without defects. The weld zone is characterized by dendritic structure, the columnar grains form in the fusion zone close to the side of the weld, and fine equiaxed crystal on the other side. Due to the welding thermal cycle, coarse grains appear in heat affected zone. The weld zone has higher impact toughness, which is two times of heat affected zone and base metal. Hardness distribution in the weld joint is more evenly, the minimum hardness is in the weld zone, the change of the hardness values in HAZ is the larger.