Effect of welding stability on process porosity in laser arc hybrid welding of dissimilar steel

Welding porosity is an important factor affecting the mechanical properties of welded joints. This study investigated the effect of welding stability on weld porosity to solve the problem of welding porosities in laser-arc hybrid welding of dissimilar steels. The type and formation mechanism of welding porosity were analyzed. The study results showed that the porosities generated during the welding process were process welding porosities. The generation of bubbles was closely related to the instability of the steam pressure inside laser keyhole. The droplet transfer form was an essential factor affecting the stability of the laser keyhole. When the droplet was in the projected transfer mode, the weld porosity could be effectively reduced. Penetration weld was also greatly helpful in reducing weld porosity.