【作者】 吴世凯； 王启明； 肖荣诗； Qiao Junnan； LI Zhujie；

【Author】 Wang Qiming;Wu Shikai;Qiao Junnan;LI Zhujie;Xiao Rongshi;Institute of Laser Engineering, Beijing University of Technology;

【机构】 北京工业大学激光工程研究院；

【摘要】 对4mm厚A7N01铝合金进行光纤激光-变极性TIG复合焊接,对比了不同焊接方法的焊缝成形特征,讨论了电弧电流对焊缝形貌及焊缝内部缺陷的影响规律,在优化的焊接工艺参数条件下,研究了复合填丝焊接接头的显微组织和力学性能。结果表明,采用激光-变极性TIG填丝复合焊接方法,能获得良好成形的焊缝,且随着电弧电流增大,焊缝成形质量显著改善;在激光功率为6k W,电弧电流为180A,焊接速度为6m/min,送丝速度为6m/min时,获得成形良好内部无缺陷的焊接接头;焊缝横截面呈典型的上宽下窄的特征,从熔合线至焊缝中心,焊缝组织依次为细小等轴晶、柱状晶、等轴树枝晶形态,且焊缝中心的等轴树枝晶晶粒尺寸自上而下逐渐减小,二次枝晶逐渐弱化;焊缝区的硬度值低于母材,存在接头软化现象,其接头抗拉强度均值为369.8MPa,约为母材的83%,延伸率约为4.0%,拉伸断裂于焊缝区,拉伸断口呈典型的韧性断裂特征。更多还原

【Abstract】 The experiments of fiber laser-VPTIG hybrid welding for A7N01 aluminum alloy with the thickness of 4 mm were carried out. The weld forming of different welding methods were compared. The effects of arc current on weld formation and internal defects of hybrid welding were discussed, and the microstructure and mechanical properties of hybrid welding joint were studied under the optimal welding process. The results indicate that a joint with good surface appearance is obtained by using fiber laser-VPTIG hybrid welding with wire, and the weld formation is improved with increasing arc current. Under the condition of 6k W laser power, 180 A arc current, 6m/min welding speed and 6m/min wire feeding rate, the joint with good formation and few welding defects is obtained. Weld cross section is characterized by the wide top weld width and narrow bottom weld width. The microstructure of the joint is composed of equiaxed grain zone(EQZ), columnar zone and equiaxed dendrite zone from the fusion line to the center of weld. The sizes of the grains and equiaxed dendrites from the top to the bottom are gradually reduced along the weld centerline. The fusion zone hardness is lower than that of the base metal, indicating the softening of the joint. The average tensile strength of joints is 369.8MPa, which is approximately 83% of base metal, and the tensile fracture occur in the weld zone, which shows the ductile characteristics.更多还原