Research on keyhole-induced porosity and melt flow kinetic behavior of 2219 alloy T-joint manufactured by dual laser-beam bilateral synchronous welding

Based on the dual laser-beam bilateral synchronous welding (DLBSW) of 2219 aluminum alloy T-shaped structure oriented to the needs of aerospace load-bearing structure requirements, the features of the melt pool flow and keyhole induced porosity of DLBSW process are researched in this paper. The surface formation of the melt pool during the welding process was observed and studied by the high-speed camera system. The thermal-fluid coupling modeling and simulation analysis were carried out for the 2219 aluminum alloy T-shaped structure DLBSW process. The temperature field, flow field, and keyhole coupling evolution behavior of the welding process was studied. At the same time, the flow field distribution characteristics of the melt pool surface were induced. Combined with keyhole coupling dynamic behavior, the effect of the driving force of the melt pool on porosity formation was explored, and the three types of porosity caused by keyhole instability during the DLBSW process were revealed.