关键词: 铝合金, 焊丝振动, 熔化极气体保护（GMA）焊, 超声, 焊缝成形, 气孔

Abstract:

Introduction of ultrasonic energy field in Gas Metal Arc （GMA） welding of aluminum alloy could effectively decrease the pore defects and improve weld formation. Ultrasonic vibration of welding wire is a feasible method of introducing ultrasonic energy field in welding process， which could avoid the disadvantages of low conversion rate of ultrasonic energy and complex welding torch. However， the effect of ultrasonic vibration of welding wire on weld formation and pore behavior in GMA welding of aluminum alloy is unclear. Results showed that after the ultrasonic vibration of the welding wire， the fluctuation range and surface roughness of the weld were reduced， and the surface brightness of the weld was increased. Weld surface formation was the best， and the width and depth of weld increased in different degrees when the vibration amplitude of the welding wire was 26.3 μm. With the increase of vibration amplitude of welding wire， depth to width ratio generally increased. Depth to width ratio increased by 9.72% when vibration amplitude of welding wire was 26.3 μm. Porosity defect of weld was obviously improved. When ultrasonic horn amplitudes were 22.8， 24.9， 26.3 μm， number of pores in the weld decreased by 76.9%， 65.7% and 71.8%， respectively， and pores were mainly distributed in the upper part of the weld. Acoustic simulation results showed that the ultrasonic energy mainly propagatds along the axial direction of welding wire， and the acoustic pressure amplitude at the lower part of the weld pool was larger. This result has a good correlation with the increase of weld penetration and the decrease of porosity at the bottom of the weld.

Key words: aluminum alloy, vibration of welding wire, Gas Metal Arc （GMA） welding, ultrasonic, weld formation, pore