Effect of post-heat treatment on the mechanical and corrosion behaviour of SS316L fabricated by wire arc additive manufacturing

[Display omitted] •WAAM is a potential technique for fabricating stainless steel components.•As-deposited wall microstructure comprises of columnar and equiaxed dendrites.•Higher tensile strength is attributed to the smaller volume of ferrite.•Post-processed samples showed better corrosion resistance than as-deposited ones.•DLEPR results confirmed the zero degree of sensitivity in heat-treated samples. The current work addresses the effect of post-processing on the mechanical and corrosion properties of SS316L fabricated by gas metal arc welding (GMAW) based wire arc additive manufacturing (WAAM) technology. During the fabrication of thin-walled structure repeated remelting occurs, and solidification causes a change in the microstructure along the building direction. The as-fabricated samples were subjected to post heat-treatment involving solution treatment and sensitization. The mechanical properties of the as-deposited and heat-treated samples were compared. Kernel average misorientation (KAM) values reveal the reduction in dislocation density due to solutionizing. Cyclic potentiodynamic polarization (Tafel scan) and double-loop electrochemical potentiodynamic reactivation (DLEPR) studies confirm that post-heat treatment can enhance the corrosion resistance. The corrosion rate ranged between 0.5 and 3.0 mils per year (mpy) and suggests that SS316L as a inexpensive material with compact passive film formation. The combination of post-heat treatment and sensitization studies could be a promising post-processing technique to certify the WAAM processed stainless-steel components for critical applications.