Numerical analysis of the molten pool vibration mode for arc-ultrasonic keyhole plasma arc welding

With considering the characteristics of keyhole plasma arc welding （K-PAW）, the resonant frequency between arc and molten pool was solved in the frequency range 15 000 Hz to 72 000 Hz by,finite element modal analysis, ClAM steel fiat butt arc-ultrasonic PAW test was carried out to evaluate the effect arc-ultrasonic frequency on weld structures. Experimental result confirmed that arc-ultrasonic with resonant frequencies treatment are more eJficient than non-resonant frequencies treatment in terms of grain size reduction and structure homogenization. But resonant frequency treatment has little effect on breaking up dendritic structures further and forming equiaxed structures at the lower part the weld.