The Effect of EN Pulsing Ratio and Repetition Frequency on the Bead Appearance and Microstructure Evolution in Aluminum Welding using Variable Polarity GMAW

Minjung Kang, Jason Cheon, Tae Hyun Lee
2021 Journal of Welding and Joining  
This study addressed the gas metal arc welding (GMAW) of Al 5183 aluminum alloy using variable polarity (VP). The effects of the electrode negative (EN) pulsing ratio and repetition frequency on the geometrical features and microstructural evolution of the deposited materials were investigated and discussed. The current and voltage were manually controlled independently for each phase to evaluate the effect of the polarity change. The influence of phase and its changing frequency on the
more » ... ency on the geometrical features and microstructure evolution were observed. The phase of the electrode affected the arc concentration and changed the amount of the deposited material and the dilution between the substrate. The EN phase is beneficial for making a finer structure than the electrode positive (EP) phase because of the lower heat input per unit mass. In addition, the size of the grains decreased as the phase change frequency increased. When the number of repetitions frequency increased within a cycle, the size of the microstructure was reduced. Consequently, strategies can be established to minimize the microstructure with VP-GMAW welding using a high EN pulsing ratio and low repetition conditions.
doi:10.5781/jwj.2021.39.2.6 fatcat:cblnjtpsfjhwrgrqex4jrqypr4