Influence of Different Thermochemical Treatments on the Dry Sliding Wear Behavior of the DIN-16MnCr5 Steel

• Boriding significantly improved wear resistance, reducing material removal ∼44 times related to untreated steel. • Nitriding, post-oxidation, and boriding exposed different k values under dry sliding conditions. • Boriding minimized abrasive and adhesive wear, while post-oxidation layers degraded under high loads. • Boriding is recommended for high-load dry environments; post-oxidation suits moderate loads. • FEA confirmed stress distribution at layer interfaces. This study investigates the influence of different thermochemical surface treatments (Nitriding, post-oxidation, and boriding) on the dry sliding wear behavior of DIN-16MnCr5 steel. The main objective was to correlate microstructural evolution and interfacial stress distribution with wear performance, providing new insights into the mechanisms governing the tribological response of multilayer surface systems. X-ray diffraction, scanning electron microscopy, and nanoindentation were used to characterize the treated surfaces, while wear tests were performed in a ball-on-flat configuration under controlled loads and sliding distances. Finite Element Analysis (FEA) was employed to simulate contact conditions and analyze stress localization and plastic strain at the interfaces between diffusion layers (Fe₃N, Fe₃O₄, and FeB/Fe₂B). Results exposed that the borided layer exhibited the highest surface hardness (⁓22 GPa) and lowest wear rate (14.1 mm 3 .Nm -1 × 10⁻⁶), followed by the oxidized and nitrided layers. FEA showed that the FeB/Fe₂B multilayer redistributed subsurface stresses, sustaining shear stresses up to ∼1261 MPa at a depth of 64 µm, compared with ∼897 MPa and 25 µm for nitrided steel. Together with the higher H/E (0.067) and H²/E³ (2.47 × 10⁻⁵) ratios, these results confirm that the superior wear resistance of boriding is governed by enhanced micromechanical stability.