Microstructure and tribological properties of electrolytic plasma nitrided high-speed steel

Abstract

In this work, the influence of electrolytic plasma nitriding on the structure and tribological properties of R6M5 high-speed steel were investigated. We found out that after electrolytic plasma nitriding of R6M5 steel a surface modified layer is formed with a thickness of 20 to 40 μm and with increased microhardness of 9000–12 200 MPa. It is established, that after nitriding surface friction coefficient of the sample steel decreased from 0.90 to 0.65, and sample wear rate reduced up to 5 times compared to the original, which indicates considerable wear resistance increase and hardness of R6M5 steel surface layer. It was also determined that abrasive wear resistance of R6M5 steel surface layer increased to 25 % as a result of electrolytic plasma nitriding. Thus, studies have demonstrated the feasibility and applicability of electrolytic plasma nitriding in order to improve the service time of cutting tools working under friction and wear conditions.