Additive manufacturing of 2209 duplex stainless steel via CCW-PAAM: microstructure and process study

Conventional single-wire additive manufacturing (AM) has several limitations, including low production efficiency and poor material utilization. These limitations hinder the development of metal 3D printing. Using combined cable wire (CCW) effectively solves these problems. Thus, this study introduces CCW based on plasma arc additive manufacturing (PAAM) to fabricate 2209 duplex stainless steel thin-walled parts (2209 DSS-TWPs). Through orthogonal experiments with range analysis and ANOVA, process optimization reveals the following optimal parameter set: a dry extension (DE) of 10 mm, a current (C) of 100 A, a scanning speed (SS) of 0.015 m/s, and a wire feeding speed (WFS) of 0.8 m/min. The 2209 DSS-TWP fabricated using these optimized parameters exhibits excellent forming quality (excellent surface finish and absence of defects). The microstructure shows an ideal 1:1 ferrite (α)/austenite (γ) ratio in the middle region. The top region has the highest α content, while the bottom region has predominant γ content. The 2209 DSS-TWP demonstrates excellent mechanical properties. Its overall average hardness (303 HV), strength, and elongation (EL) all meet GB/T 4237-2015 and ASTM-A890 guidelines. The middle region exhibits superior mechanical performance due to its balanced phase ratio. Compared to GB/T 4237-2015, ultimate tensile strength (UTS), yield strength (YS) and EL have increased by approximately 14%, 48%, and 56%. These results demonstrate the potential of CCW-PAAM technology for manufacturing high-performance DSS parts in industry.