Effect of synchronizing GMAW and LBW processes on weld quality and mechanical characteristics of structural steel

Abstract

The combination of two or more welding processes within the same welding pool offers significant advantages over the limitations of individual processes. This paper presents an experimental investigation of Hybrid Laser Arc Welding (HLAW) achieved by synchronization Gas Metal Arc Welding (GMAW) and Laser Beam Welding (LBW), with the aim of evaluating theirs positive effects on the weld characteristics. The experiments were performed on 12 mm thick S355J2+N structural steel in a zero-gap butt joint configuration. The process parameters were kept constant for the individual GMAW and LBW processes, as well as for the HLAW process: laser beam power 8 kW, welding speed 1,5 m/min, welding current 316 A and arc voltage 33,1 V. The quality of the weld and its mechanical characteristics were determined by non-destructive testing, tensile testing and hardness measurements. The experimental results show that the applied welding parameters enable deeper penetration by HLAW process compared to conventional GMAW process. The synergistic interaction between the electric arc and laser beam improves energy efficiency and reduces stringent edge preparation requirements, resulting in lower overall heat input, improved tensile strength and a hardness reduction of at least 50 HV, particulary in the laser zone. These findings demonstrate the potential of the HLAW process as an efficient and reliable welding process for high-productivity industrial applications.