Optimization of weld bead geometry in single-pass WAAM-CMT deposits of Inconel 625 and DSS 2507 on mild steel using RSM and ANN models

This study investigates the influence of wire feed rate and travel speed on the geometry of weld beads and the dilution of WAAM components of DSS-2507 and IN-625 alloys employing the CMT approach. The geometry of the weld beads, including width, height, and dilution percentage, has been examined via the CCD approach alongside RSM and ANN. The ANN has yielded a lower prediction error than the RSM, hence affirming superior prediction accuracy. All trials were conducted with a constant shield gas flow rate of 15 L/min. The optimum wire feed rate of 6800 mm/min, travel speed of 120 mm/min, and resultant dilution of 4.18% for the DSS-2507 produced weld beads with a height of 4.710 mm and a width of 6.686 mm. The optimum parameters for IN-625 include a wire feed rate of 6200 mm/min, a travel speed of 120 mm/min, and a consequent dilution of 4.95%, yielding a weld bead height of 4.98 mm and a width of 6.312 mm. Optical microscopy of the components has disclosed a ferrite–austenite structure exhibiting columnar features and Laves phases. The microhardness of the components, measured in VHN, yielded values of 297–316 for DSS-2507 and 211–241 for IN-625, respectively. X-ray diffraction analysis confirmed the presence of a dominant γ-austenitic phase in the IN-625 deposit, while the DSS-2507 deposit exhibited a typical duplex structure consisting of both ferrite (α) and austenite (γ) phases. The residual stresses in the parts have been measured along the weld beads.