High-temperature dry sliding wear behavior of additively manufactured austenitic stainless steel (316L)

Austenitic steels are commonly used in aero-engine components owing to their higher thermal resistance to wear and corrosion. This study investigates the high -temperature dry sliding wear behavior of direct metal laser -sintered (DMLS) austenitic stainless steel (SS 316L) up to 400 degrees C. A dry sliding reciprocating wear test conducted on a high -frequency tribometer with a ball -on -flat setup. High -hardness chrome steel (900 HV0.5) and alumina (1165 HV0.5) balls of 6 mm diameter were used as the steel and ceramic counterbodies against 316L specimen (320 +/- 5 HV0.5). When tested against the chrome steel, the initial average coefficient of friction (CoF) decreased to a lower value (0.45) during the initial running -in period. However, with rising temperatures, the CoF also increased, stabilizing at 0.6 under steady-state conditions. A similar CoF pattern was observed in experiments with the alumina counterbody. Wear resistance declined at 100 degrees C, followed by an increase at 200 degrees C due to the development of an oxide glaze on the surface. Subsequently, wear resistance decreased as the temperature continued to rise. Up to 200 degrees C , the wear mechanism was characterized by a combination of abrasive and oxide debris wear, transitioning to adhesive wear with plastic deformation at higher temperatures (400 degrees C). Diffraction (XRD) analysis revealed the formation of oxide layers and martensite phase at higher temperatures, contributing to the observed improved wear resistance around 200 degrees C . However, these oxide layers were progressively removed from the surface at 400 degrees C, leading to an increased wear. The measured wear rates are two times lower, up to 200 degrees C, compared to the reported values for conventional 316L due to the fine microstructure and higher hardness of DMLS SS 316L. This results in potentially rendering it suitable for applications where high -temperature (up to 200 degrees C) wear -resistant SS is needed. This study provides further insights into the importance of post -treatment of DMLS parts for temperature beyond 400 degrees C.