Thermal modeling and characterization of wire arc additive manufactured duplex stainless steel

In this study, Wire Arc Additive Manufacturing (WAAM) based Directed Energy Deposition (DED) process is used to build two parts, tube and wall from 2209 Duplex Stainless Steel. Duplex stainless steel is extremely effective against stress corrosion cracking due to existence of an equal portion of austenite and ferrite phases. The challenge is monitoring of the process parameters and cooling rate to promote ferrite phase formation. To this end, three-dimensional transient thermal models of the additive manufactured (AM) parts are presented and the simulated thermal cycles are verified with the experimental results. The correlation between the calculated cooling rates and the phases formation in the WAAM parts is studied and revealed. The results highlight that slow cooling rate of the built layers at elevated temperatures promote austenite formation significantly in a ferrite matrix. Furthermore, the experimental mechanical examinations will illustrate the quality of the WAAM-made parts and compare their mechanical properties with their wrought counter-parts.