Multi-objective Optimization of Short-Circuit Gas Metal Arc Welding for Overhang Structures by Grey Relational Analysis Integrated Taguchi Method

Abstract

Short-circuit transfer gas metal arc welding (GMAW) has shown great potential in wire and arc manufacturing (WAAM) of complex components with overhang structures. The difficulties lie in the identification of the short range of process window and remaining a stable process. This paper combines Taguchi's method with grey relational analysis to explore the effects of short-circuit transfer process parameters on multiple bead quality performances including aspect ratio, dilution rate, number of humps, and hardness gradient, followed by multi-objective optimization and experimental validation. The results show that welding voltage has the most significant effect on aspect ratio and dilution rate, while welding speed is the most important factor influencing number of humps and hardness gradient. As welding voltage increases, both aspect ratio and dilution rate keep increasing. With increase in welding speed, the number of humps and hardness gradient are increased. The optimal combination of process parameters for short-circuit transfer robotic GMAW of Q235 steel is a welding current of 80 A, a welding voltage of 22 V, a welding speed of 30 cm min⁻¹, and a travel angle of 60°. The research outcomes provide theoretical basis for the industrial application of short-circuit transfer GMAW for WAAM of overhang structures.