Characterization of Wire ARC Additively Manufactured SS308L: Study of Microstructure and Mechanical Properties

Abstract

Cold Metal Transfer (CMT) and Metal Inert Gas (MIG) welding based Wire Arc Additive Manufacturing (WAAM) is carried out to fabricate a 3D slab of SS308L having approximate dimension (150  25  30) mm3 . Location-specific microstructure evolutions as well as anisotropic mechanical properties of the as deposited part are studied. It is observed that microstructure of WAAMed SS308L consists of grain boundary ferrites (δ) within austenitic matrix. Different δ ferrite morphologies (skeletal/ vermicular and lathy) are witnessed at different locations of the built. The bottom region of the slab exhibits higher tensile strength than the top. The average tensile strength of the as built SS308L obtained is ~ 547 MPa. 97.6 % relative density is achieved in WAAM. Post-heat treatment (1100 °C, 3 h) reduces δ ferrite content and promotes significant grain growth. Post-heat treated specimen exhibits lower microhardness than the as built counterpart.