采用单组分活性剂 (AlF3 和 LiF)、3组分 (AlF3+30％LiF+10％KF-AlF3)和 4 组分 (AlF3+30％LiF+ 10％KF-AlF3 + 10％K2SiF6)混合组分活性剂进行2219高强铝合金直流正极性活性TIG焊 (DCSP A-TIG),研究4种类型活性剂对焊缝表面成型、焊缝内部质量(气孔)、焊缝熔深、电弧形态、接头组织与力学性能的影响.结果表明:涂覆活性剂有助于去除2219铝合金表面的氧化膜,提高焊缝表面成型质量,涂覆4组分活性剂的DCSP A-TIG焊缝表面成型质量最佳;与变极性TIG焊 (VPTIG)焊缝内部质量相比,DCSP A-TIG焊接方法可显著降低2219铝合金焊缝内部气孔的产生; AlF3单组分活性剂可显著增大焊缝熔深,其电弧形态具有明显的拖弧现象;DCSP A-TIG焊焊缝组织具有与母材相同的组织组成物,电流对A-TIG焊缝组织影响较大,增大焊接电流,会造成接头晶粒组织粗大;涂覆4组分活性剂的DCSP A-TIG接头强度和伸长率最高,与VPTIG焊接头力学性能具有相近的技术指标.2219高强铝合金的DCSP A-TIG焊接方法具有很大的工程应用价值.%Straight polarity direct current method (DCSP A-TIG) was applied to join 2219 high strength aluminum alloy, and the effects of single-component (AlF3, LiF), three-component (AlF3 + 30％LiF+10％KF-AlF3) and four-component (AlF3 + 30％LiF +10％KF-AlF3 +10％K2SiF6) activating flux on weld face forming, weld quality (porosity), arc shape, weld penetration, joint microstructure and mechanical properties were studied. The results show that adding activating flux helps to remove the oxide film on the weld face of the 2219 aluminum alloy, improve the weld surface forming quality; the four-component activating flux of weld face forming is the best; compared with the weld quality of variable polarity TIG welding (VPTIG), DCSP A-TIG welding method significantly reduces the porosity generation in 2219 aluminum alloy weld; AlF3 single-component activating flux obviously increases the weld penetration, which has obvious dragged arc phenomenon; DCSP A-TIG welded seam has the same structure component as the parent metal. Welding current has a greater influence on DCSP A-TIG weld microstructure, increasing current may result in the coarsening of the joint microstructure. The strength and elongation of the DCSP A-TIG welding joint, which are coated with four-component activating flux are the highest, and the mechanical properties are nearly the same as VPTIG welding. The DCSP A -TIG welding method of 2219 high strength aluminum alloy is of great value to the engineering application.
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