Microstructure and mechanical properties of 308L steel wall fabricated using high-current manual GMAW-based additive manufacturing

Abstract

This study investigates the impact of high arc current on the mechanical properties and microstructure of thin-walled material fabricated using manual GMAW wire arc additive manufacturing (WAAM). The ER308L electrodes were used to fabricate samples using high currents of150A, 170A, and 190A; voltages of11 V, 11.5 V, and 12 V; and travel speeds of400 mm/min, 435 mm/min, and 450 mm/min. It was found that increasing the current improves the mechanical properties, with optimal value in 170A. The ultimate tensile strength (UTS) increases by around 3 % from 605 ± 9 to 623 ± 8 MPa at 190A. The yield strengths (YS) are 370 ± 6, 384 ± 5, 371 ± 8, corresponding to 3.8 % increase at 170A then decrease 3.6 % at 190A. The microhardness increases 3.7 % with higher current, from 212.00 HV0.5 at 150A to 293.33 HV0.5 at 190A. The Elongation are 42.07 %, 41.8 %, and 41.3 %, slightly reduce for 150A, 170A, 190A respectively. The Microstructure analysis revealed δ-ferrite and γ-austenite dendrites, with lathy and skeletal morphology variations.