Microstructural and mechanical properties analysis of SS 316L structure fabricated using CMT-wire arc additive manufacturing

Abstract

Integrating robotic arm technology with cold metal transfer (CMT) has revolutionized wire arc additive manufacturing (WAAM). The research work consists of the fabrication of SS 316L WAAM using the CMT technique. Investigations of mechanical and microstructural properties, i.e. residual stress measurement (RSM), microhardness (MH), ultimate tensile strength (UTS), percentage elongation (PE), and microstructure of WAAM sample and cold rolled (CR) plate, results were compared. WAAM attained an UTS of 590 MPa, with an average yield strength (YS) of around 302 MPa, exceeding the CR plate’s UTS of 557 MPa while maintaining a similar YS of 305 MPa. WAAM and the CR plate exhibited nearly identical PE, with 64% and 62% values, respectively. Residual stress analysis revealed that the WAAM sample showed an average compressive residual stress of 124 MPa, accounting for 87% of the average residual stress observed in the CR plate, which measured 142 MPa. The MH profile of WAAM revealed an average value of 230 HV0.5, accounting for 88% of the MH observed in the CR plate at 260 HV0.5. The performance of WAAM closely matched that of the CR plate in terms of residual stress and MH.