Microstructure characterization and tensile properties of CMT-based wire plus arc additive manufactured ER2594

A wall component of super-duplex stainless steel was developed using cold metal transfer (CMT)-based wire + arc additive manufacturing (WAAM) technique with an ER2594 wire. The microstructure of the as-deposited wall was explored using optical microscopy and electron backscattered x-ray diffraction (EBSD) analysis. Ferrite count analysis indicated that the austenite-ferrite phase balance was altered along the as-deposited wall body. The average ferrite count near the as-deposited wall was 24.5%, compared with 32.3% in the root region. Widmanstätten and grain boundary austenite were formed near the wall boundary, and intragranular austenite was observed in the different layers. Secondary austenite in the transition layer was also observed. EBSD analysis revealed the sigma (σ) phase and austeno-ferritic phases across the WAAM wall. The tensile and yield strengths of the samples of the as-developed WAAM wall were almost identical regardless of orientations/tropism. [Display omitted] •CMT based WAAM technique was adopted to develop thick wall structure of ER2594.•The yield and tensile strengths of the WAAM joints were greater than those of the cast SDSS 6A in the ASTM A 890 standard.•The austeno-ferrite phase balance was greatly affected due to complex thermal cycles of WAAM.