Properties of UNS S32760 Duplex Stainless Steels Powders and L-PBF Components as Function of Different Processing Gases

Super duplex stainless steels (SDSS) combine the advantages of ferritic and austenitic steels and reach an excellent combination of mechanical and corrosion properties. The paper focuses on the production of UNS S32760 (X2CrNiMoCuWN25-7-4, AISI F55, 1.4501) SDSS powders through Vacuum induction melting Inert Gas Atomization (VIGA) with different gas atmospheres, Argon or Nitrogen. The effect of the different gases used during the melting and the atomizing on the characteristics of the final powder was investigated, in terms of granulometry, morphology, microstructure, chemical composition (also taking into account light elements such as N, O, H, C, and S). Powders were then processed by means of Laser Powder Bed Fusion (L-PBF) and microstructural features and mechanical properties of produced components were analyzed in the as processed state and after thermal treatments, properly optimized to obtain a good balancing between the α ferrite/austenite phases.