Analysis on the stability of the single weld pool formed during the triple-electrode high speed CO2 welding

The pinch instability theory with free surface and wave superposition principle was applied to understanding the critical disturbance wavelength and the theoretical bead width for the single weld pool formed during the triple-electrode high speed CO2 welding.In addition,the reason for higher stability in the single weld pool was analyzed.Then single-,twin-,and triple-electrode overlaying experiments were conducted,it was found that triple-electrode CO2 welding can improve welding efficiency greatly without reducing the weld quality.The results indicated that the oscillation frequency of the weld pool increased,oscillation wavelength decreased,and bead width increased with the increase of welding electrodes under the same disturbance circumstances.