Comparison of Wear Resistance of Lean Medium Mn AHSS After Q&P Heat Treatment

This study evaluates the tribological properties of lean medium manganese advanced high-strength steel (AHSS) subjected to five different heat treatment processes. The tests were conducted under dry reciprocating conditions using the ball-on-flat method, with a G40 steel ball, a 10 N load, and 1000 cycles at room temperature. Friction behavior, wear resistance, nanoindentation hardness, surface roughness, and microstructural changes were examined. The results showed that heat treatment significantly influenced the microstructure and hardness of the samples. The Mn-Q sample, with fresh martensite, achieved the highest hardness (483 HV5), while the Mn-Q&P 500 °C sample had the lowest (336 HV5), with a 30% reduction due to tempering. The Mn-HR 500 °C sample showed the highest surface roughness (Sa = 1.876 μm) due to microstructural heterogeneity. Despite similar coefficients of friction across all samples (0.55–0.57), the Mn-Q&P 500 °C sample exhibited the best wear resistance, 18% higher than the Mn-HR 500 °C variant. Wear mechanisms were identified as a combination of abrasion and oxidation, where the latter slightly reduced the coefficient of friction (COF) but increased surface degradation. These findings highlight the potential of lean medium Mn AHSS for tribological applications, offering a favorable balance of wear resistance and frictional stability.