Plasma nitriding of additively manufactured 316L austenitic stainless steel produced by laser power bed fusion and metal binder jetting

Among the additive manufacturing methods, laser powder bed fusion (L-PBF) and metal binder jetting (MBJ) are well established technologies for producing complex-shaped 316L components. Plasma nitriding provides an effective approach to enhance their surface properties, thereby broadening their application potential. Since L-PBF and MBJ generate distinct microstructures, it is essential to evaluate their influence on the resulting mechanical and tribological performance. Therefore, L-PBF- and MBJ-316L are plasma nitrided at temperatures of T PN1 = 380 °C and T PN2 = 430 °C for 10 h and compared with conventionally wrought 316L. The thickness of the S phase is independent of the initial microstructure, exhibiting values of δ PN1 ≈ 3 μm at T PN1 and δ PN2 ≈ 12 μm at T PN2 . Nanoindentation reveals a significant increase in near-surface hardness to 1230–1400 HV IT at T PN1 and 1420–1520 HV IT at T PN2 , associated with austenite lattice expansion caused by interstitial dissolution of nitrogen. In contrast, Vickers microhardness is additionally influenced by the core microstructure, with plasma nitrided MBJ-316L showing lower values than L-PBF-316L. The enhanced surface hardness significantly improves the resistance against abrasive wear of all 316L variants. Overall, the plasma nitriding processes developed for conventionally manufactured 316L steels can be successfully applied to additively manufactured 316L. • Plasma nitriding of 316L produced by L-PBF, MBJ, and conventional method • S phase thickness is similar across manufacturing methods • Nanoindentation reveals similar near-surface hardness in all manufacturing methods • Plasma nitrided 316L shows enhanced resistance against abrasive wear