Parametric study and characterization of wire arc additive manufactured steel structures

This paper focuses on selecting optimal process parameters for uniform single-layer weld bead deposition and the characterization of structures manufactured by GMAW-based wire arc additive manufacturing (WAAM) process. The results reveal that the obtained grain structures vary due to the local thermal cycle. Near to the base of the fabricated part, ferrite with pearlite structures is observed. At the same time, the observed grains become coarser along the deposition direction. Again adjacent to the final layer, finer grains are observed with ferrite and thin strips of bainite, which has been confirmed through XRD analysis. Also, the formation of different chemical compounds such as ferrite, cementite, bornite, and martensite has been identified at different layers. Investigations of surface defects using dye penetration test and corrosion behavior of the component using the weight loss method have also been conducted. The observed surface defects like cracks and porosity are primarily present in the interface of the upper layers. The measured Vickers micro-hardness is found different in different wall structures. The micro-hardness values in the flat and circular wall are recorded as 162.806 HV and 172.191 HV, respectively.