Research On Welding Process And Effect Of Ultrasonic In Ultrasonic-TIG Welding Of Aluminum

The TIG welding method can provide high quality welds for its steady process and excellent weld bead appearance, but it is an inefficient welding method because of its shallow penetration. Ultrasonic-TIG can fill up a deficiency for The TIG welding method to let arc shrink and energy concentration, to improve the welding efficiency and performance. In order to explore this method in the advantages of aluminum welding, the ultrasonic welding system had been improved, the welding process was studied deeply, and the structure and properties characteristics of welding seam had been analyzed.First of all, for the welding of aluminum alloy, the radiation terminal of the U-TIG welding system, the cooling organization and the tungsten electrode connection mode had been improved, thus caused the U-TIG welding system to meet the requirements of AC and DC welding of aluminum alloy, after the improvement, the system had stable and usable operated.The research on DC helium TIG welding process in aluminum alloy has studied. First, the influence of the welded depth-width radio on the different electric arc length and the radiation terminal height has analyzed, the experimental result showed that when the technological parameter matched well, the welded depth-width radio is maximizing, complete penetration was achieved by using a smaller standard melts. The microstructure of welding seam was analyzed, discovered that the welded joint area grain refining was obvious, columnate crystals in the TIG welded joint transformed into tiny belt-shaped or the equiaxed grain by the effect of ultrasonic, the welded joint got more uniform distribution of ingredients.The research on AC TIG welding process in aluminum alloy has studied. In the flat surfacing welding experiment, while the welding current, the electric arc length changing, the effect ultrasonic was also changing. to butt welding experiment of 2219 aluminum alloy board was carried on in well-matched technological parameter. The result had proved ultrasonic-TIG welding can achieve one-sided welds with back formation by using a smaller standard. In the same welding process, the ultrasonic-TIG welded joint center appeared wide range of the equiaxed grain, the welded joint fusion sector width reduced, the heat-affected zone and the welded joint got more uniform distribution of ingredients. In the analysis of welding crack, ultrasonic-TIG welds can prevent the welding crack effectively, moreover, when using the medium arc length and the small welding current, ultrasonic-TIG was helpful in the reduced weld porosity of welded joint. The mechanical properties test demonstrated that the tensile strength of welded joint by ultrasonic-TIG welding method was higher than by ordinary TIG welding method.The reason of arc contraction in the ultrasonic-TIG had discussed initially, and proposed two kinds of function mechanisms: Sonic flow power and fluid cooling compression mechanism. The effect of ultrasonic to weld porosity had been explored, and pointed out the sonic flow power was the key that influenced the number of weld porosity.