Effects of solution treatment, precipitation hardening, and shot peening on the cavitation erosion resistance of 17‑4PH steel produced by additive and conventional methods

17-4PH stainless steel is widely used in hydraulic components exposed to cavitation, yet its cavitation erosion resistance (CER) depends strongly on both the manufacturing route and the applied post-processing. This study compares the CER of conventionally processed and DMLS-fabricated 17-4PH steel after solution treatment, precipitation hardening, and shot peening with glass, ceramic, and steel media. The novelty of the work lies in the systematic comparison of these post-processing routes across both manufacturing methods, supported by a structure–property analysis of hardness, surface morphology, phase composition, crystallite size, and microstrain-derived estimated stress magnitude. The DMLS material showed consistently higher CER than the conventional steel. The best performance was observed for the precipitation-hardened and ceramic-shot-peened DMLS specimen, which exhibited an erosion rate of 1.49 µm h −1 , compared with 4.71 µm h −1 for the untreated conventional specimen, representing an improvement of approximately 216%. The superior cavitation performance of the DMLS material was associated with broader retention of the α/γ microstructure after post-processing, indicating that CER is governed not only by hardness, but also by phase constitution and the condition of the near-surface layer.