2219高强铝合金超快变换VPTIG焊缝组织和性能

研究开发了一种适用于铝合金材料的新型超快速变换变极性方波电弧焊接技术,以2219-T87高强铝合金为试验对象,采用高频变极性TIG电弧焊接工艺,研究了变极性方波电流频率对焊缝显微组织和拉伸性能的影响.结果表明,随着电流极性变换频率的提高,2219-T87铝合金焊接接头显微组织明显细化,由粗大柱状晶转变为细小等轴晶,接头抗拉强度和断后伸长率显著提高,接头断裂类型由脆性断裂转变为"韧性+脆性"的混合型断裂模式.当电流极性变换频率为1kHz时,2219-T87焊接接头抗拉强度和断后伸长率分别达到母材金属的69%和58%.

Microstructure and mechanical properties of ultrafast-convert VPTIG arc welding of 2219 high strength aluminum alloy

A novel ultrafast-convert intermediate and high-frequency variable polarity arc welding technology for aluminum alloys was developed.The effect of variable polarity current frequency on the microstructure and mechanical properties of 2219-T87 weld joints was researched based on the variable polarity TIG welding process.The experimental results show that the structure in the weld zone is predominantly columnar in the case of lower variable polarity current frequency.The grain structures in the weld zone become finer and more equiaxed with the increase of current frequency.Tensile strength and percentage elongation of the weld joints also improve predominantly.The type of weld fracture is changed from brittle to the mixture of dimple and brittle.Under the current frequency of 1 kHz,the rates of weld tensile strength and percentage elongation of the joints are 69% and 58% than those of the base metal respectively.