Microstructural and Mechanical Characterization of Wire Arc Additive Manufactured Stainless Steel 316L

Robotic arm technology coupled with Cold metal transfer (CMT) has revolutionized Wire arc additive manufacturing (WAAM), gaining widespread recognition in the aerospace, marine, and automotive sectors. In WAAM, managing residual stress poses challenges due to temperature gradients, phase transformations, and uneven cooling, leading to distortion and potential crack failures. This study is centered on the CMT-assisted fabrication of SS 316L WAAM utilizing a 1.2 mm diameter. It involves a comparative analysis of residual stress, microhardness, ultimate tensile strength, and percentage elongation between SS 316L WAAM, and the results were compared with those of wrought SS 316L. The WAAM sample quantified an average residual stress of 90.73 MPa (compressive), marking an 18% increase compared to the wrought stainless steel’s residual stress of 76.68 MPa (compressive). The microhardness profile of the WAAM sample revealed an average value of 269.51 HV0.5, signifying a substantial 4.48% increase over the wrought SS 316L microhardness of 257.94 HV0.5. The WAAM sample’s ultimate tensile strength was 577 MPa, 16.56% greater than the wrought SS 316L, having an ultimate tensile strength of 495 MPa, while their respective percentage elongation was 86% and 87%. WAAM demonstrated superior performance in terms of ultimate tensile strength, residual stress, and microhardness.