Investigations and Multi-response Optimization of Wire Arc Additive Manufacturing Cold Metal Transfer Process Parameters for Fabrication of SS308L Samples

Wire arc additive manufacturing (WAAM) is ideal for producing large components, due to rapid material deposition. WAAM complemented by the cold metal transfer (CMT) now onwards referred to as WAAM-CMT is used nowadays to fabricate due to its low heat input characteristics so that interlayer temperature can be reduced for better mechanical properties. In this work, the effect of three input process parameters of the WAAM-CMT process, i.e., current, welding speed and gas flow rate, each at three levels, on four mechanical properties, viz. ultimate tensile strength (UTS), microhardness (MH), compressive residual stress (CRS) and total elongation (TE), of SS308L austenitic stainless steel fabricated samples was investigated using Taguchi’s L9 orthogonal array. Filler wire of SS308L (Ф = 1.2 mm) was used to additively manufacture the samples. Further, the optimum setting of the input process parameters resulting in the optimum multiple responses was determined using an integrated fuzzy analytical hierarchy process (AHP) and fuzzy measurement alternatives and ranking according to compromise solution (MARCOS) method and analysis of means (ANOM). As a result of the X-Ray diffraction (XRD) and energy-dispersive X-Ray spectroscopy (EDX) plots, it can be concluded that the sample fabricated at an optimal setting of input parameters has a composition similar to that of industrial stainless steel. The optimal input parameters were discovered to be 140A current, 8 mm/s welding speed, and 16 l/min shielding gas flow rate, which also revealed that current was the most influential parameter for affecting the multiple responses followed by welding speed and gas flow rate.