Effect of heat treatment temperature on the phase composition, mechanical properties and corrosion resistance of wire arc additive manufactured duplex stainless steel

Purpose This study aims to investigate the influence of heat treatment on the microstructure and mechanical properties of wire arc additively manufactured (WAAM) duplex stainless steel (DSS). Design/methodology/approach Gas metal arc welding based WAAM process was used for the fabrication of DSS wall structure using ER2209 filler wire. The as-fabricated WAAM part is predominantly austenitic (exceeding 80%), suggesting that heat treatment is necessary to attain a balanced phase fraction. The DSS samples were fabricated using WAAM process with ER2209 filler wire and subjected to heat treatment at various temperatures of 1250 °C, 1263 °C, and 1275 °C for 1 h followed by rapid water quenching. Electron backscattered diffraction analysis was used to evaluate the microstructure evolution during WAAM process and heat treatment process. Tensile test and Vickers microhardness analysis were conducted to determine the mechanical properties. Findings Heat-treatment at 1250 °C shows a balanced phase fraction (1:1) and improved corrosion resistance (1.541 mpy) than the as-fabricated and other heat-treated samples. Also, the tensile strength of all heat-treated samples was comparatively higher than the as-fabricated WAAM sample. Research limitations/implications This study mainly focused on demonstrating post-heat treatment conditions experimentally to enhance the strength and reliability of WAAM-fabricated DSS, benefiting applications in marine, offshore, chemical, and structural industries. Improved strength supports sustainability and lowers lifecycle costs. Originality/value This study provides a critical analysis of the effects of heat treatment temperature on phase composition, mechanical performance, and corrosion behavior in WAAM-fabricated DSS. These observations highlight the prospects of post-heat treatment in improving the structural integrity and performance of WAAM-fabricated DSS parts.