Investigation of pulse VP-TIG welding process of 2219/5A06 dissimilar aluminum alloy

In order to obtain the best performance of welded joints, dissimilar aluminum alloys of 2219-T87 and 5A06-H112 with a thickness of 5.5 mm was joined by pulsed VP-TIG butt welding. The L27(3⁹) type orthogonal table with five process parameters and three levels were designed, and the interaction between three factors was considered at the same time. The influence of each factor on the tensile strength of the joints was analyzed, and the results show that the influence of the process parameters on the joint performance is in the order: welding speed > groove angle > peak current > pulse frequency > wire feeding speed. Through orthogonal optimization, an ideal defect-free welded joint was obtained. The mechanical properties, microstructure and corrosion properties of the optimized welded joint were tested. The results show that the fracture edge of the joint was near the fusion line on the 2219 side, where the strain was the largest and the hardness was the lowest. The corrosion resistance of the 2219 side fusion line and the weld area is the worst, and it is the location where pitting corrosion occurs preferentially.