Procedure optimization and performance study of GTAW-WAAM ER2594 duplex stainless steel based on response surface methodology

Purpose The purpose of this study is to optimize gas tungsten arc welding (GTAW)-based wire arc additive manufacturing (WAAM) for fabricating ER2594 duplex stainless steel (DSS) thin-walled components and to correlate the resulting microstructures and mechanical properties with the optimized processing conditions. Design/methodology/approach Response surface methodology (RSM) with a three-factor, five-level experimental design was used to quantify the effects of welding current, welding speed and wire-feed speed on bead geometry (bead width and shape factor) and to develop a predictive model. Thin-walled components were then fabricated under the optimized parameters, followed by EBSD characterization of phase constitution and texture and room-temperature tensile testing. Findings Under the optimized parameters, thin-walled components were deposited uniformly with a machinable fraction > 90%. EBSD confirmed a ferrite–austenite duplex structure (43.6% ferrite and 56.4% austenite) with a pronounced < 001>//BD ferrite fiber texture and a more dispersed austenite texture. The tensile properties averaged 596.2 MPa in yield strength, 732.9 MPa in ultimate tensile strength and 39.3% in total elongation, indicating a favorable strength–ductility balance. Originality/value This work addresses the need for process optimization in GTAW-WAAM of ER2594 DSS, whose thin-wall formability and duplex phase balance are highly sensitive to heat input and thermal cycling; provides an RSM-based route to optimize GTAW-WAAM of ER2594 DSS thin-walled components; and establishes a processing–geometry–microstructure–property link under optimized processing, supporting reliable mechanical performance and microstructural tailoring for high-performance ER2594 DSS thin-walled WAAM components.