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

Abstract

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°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°C, followed by an increase at 200°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°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°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°C . However, these oxide layers were progressively removed from the surface at 400°C, leading to an increased wear. The measured wear rates are two times lower, up to 200°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°C) wear-resistant SS is needed. This study provides further insights into the importance of post-treatment of DMLS parts for temperature beyond 400°C.