Analysis and improvement of laser wire filling welding process stability with beam wobble

The reasonable selection of laser welding modes, namely keyhole mode and heat conduction mode, is based on the practical application requirements. The results show that the heat flux rapidly decreases and beam moving velocity increases with the beam wobble amplitude of 2.0 mm and frequency of 150 Hz, promoting the transformation of keyhole mode to heat conduction mode. Wider and shallower weld morphology is obtained. The improvement of keyhole stability and modification of liquid metal fluidity promote the overflow of bubbles. In case of beam wobble welding, the movement and turbulence of weld pool driven by the beam wobble help to break the columnar crystals. Welding of 40-mm thick plates without incomplete fusion and pore defects is achieved by suitable beam wobble parameters.