Study on Properties and Microstructure of Wire Arc Additive Manufactured 2209 Duplex Stainless Steel

In the last two decades, wire arc additive manufacturing (WAAM) has emerged as a cost-effective alternative to traditional additive manufacturing (AM) processes, particularly for producing medium-to-large-scale components. The primary advantages of wire-based AM include simplified automated production and enhanced control and flexibility in the fabrication process. In this study, the gas metal arc welding (GMAW) process was used to produce cylindrical components from 2209 duplex stainless steel (DSS) using the WAAM technique. The mechanical properties and microstructural characteristics of the 2209 DSS cylinders were examined. The microstructure of the components varied from the bottom (region (1)) to the top (region (2)), resulting in a hardness difference between 301 HV0.5 and 327 HV0.5, and an impact toughness variation from 118 to 154 J. Additionally, the tensile properties exhibited anisotropic characteristics: the ultimate tensile strength and yield strength ranged from 750 to 790 MPa and from 566 to 594 MPa, respectively. The complex heat cycles and cooling rates during the WAAM process significantly affected the primary phase balance (50/50 austenite/ferrite) in the produced cylinder. In the GMAW-processed component, sigma-phase precipitation was observed at the boundaries of the ferrite grains. The increase in the percentage of austenite from region (1) to region (2) was attributed to a decrease in the cooling rate and a longer time for solid-state phase transformation.