Effect of Low-Frequency Pulse Modulation on Microstructure and Mechanical Properties of Aluminum Alloy Joints
There are many ways to achieve double-pulse MIG welding. At present, two kinds of double-pulse MIG welding are widely used. One representative method is that the wire feed speed and the welding current are periodically switched at low frequency with the Kemppi-Pro enhancement and Fronius. The other representative method is the speed of wire feeding with OTC. In this paper, the strong–weak pulses and weak–strong pulses are introduced between the strong and weak pulses of the traditional double-pulse MIG welding, TP-MIGW based on the modulation of the trapezoid wave, the effects of different frequencies on the morphology, and mechanical properties of aluminum alloy joints were studied. Through experiments, it is proved that proper TP-MIGW modulation waveform can significantly reduce defects such as nonfusion and porosity of joints, and good weld formation and reliable mechanical properties of joints are obtained.
KeywordsDouble-pulse MIG welding Low-frequency Trapezoid wave
Thanks for the help of Prof. Jiaxiang Xue of the South China University of Technology in this article. Thanks for the National Science Foundation of China (51875213); the Fujian Natural Science Foundation (2018J01503,2018J01541); the Fujian Provincial Education Hall science and technology class A (JA15486); the 2015 Dongguan city to introduce third batch of innovative scientific research team project (2017360004004), and the Longyan Science and Technology Project (2017LY68).
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