The microstructure and mechanical properties of duplex stainless steel components fabricated via flux-cored wire arc-additive manufacturing

Abstract In this research, the wire arc additive manufacturing (WAAM) of duplex stainless steel (DSS) was firstly conducted using flux-cored wires as the feedstock material. Homogeneous microstructure was obtained in the WAAM DSS component fabricated using the commercial E2209 welding wire as the filler material. However, the average austenite content reached up to 74%, which exceeded the standard limitation. Electron backscatter diffraction (EBSD) measurements indicated that the austenite phase exhibited strong 〈101〉//Z texture, and the ferrite phase exhibited strong 〈001〉//Z texture. Evaluations of the mechanical properties revealed that the strength of the WAAM DSS component fulfilled the standard requirements of the cast DSS components, and its impact toughness at −40 °C exceeded that of commercial hot rolled LDX 2101 DSS plate. To modify the austenite content in the as-deposited DSS, two novel flux-cored wires were designed and produced for the flux-cored wire arc-additive manufacturing (FCWA-AM) process. These materials allowed the reduction of the austenite ratios to 37% and 45% in the as-deposited DSS components. The results of this work demonstrated that the FCWA-AM technique is an applicable WAAM method for producing DSS components with desired microstructures and good mechanical properties.