Improvement of Tribological Properties of Steel Camshaft by Plasma Nitriding

A. Dayança, B. Karacaa, L.C. Kumruoğlub aESTAŞ Eksantrik San. ve Tic. A.Ş., 58060 Sivas, Turkey bCumhuriyet University, Department of Metallurgy and Materials Eng., 58100 Sivas, Turkey

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In this study the effect of plasma nitriding on microstructure, hardness and tribological properties of 31CrMoV9 quality steel camshafts was investigated. In the first stage the NC codes to be used during the production of the steel camshaft 31CrMoV9 were determined by the ESPRIT program and the machining simulation and then the machining were carried out by turning-milling-grinding processes for this purpose. Plasma nitriding was conducted on machined and grinded camshafts for 120 and 240 minutes for each gas mixture at the gas mixing ratios of 80% H2 + 20% N2, 90% H2 + 10% N2, 94% H2 + 6% N2 at 500°. Plasma nitrided camshafts were examined by optical microscopy, SEM, XRD analyzes and mechanical tests (hardness and wear). For the steel camshaft made from 31CrMoV9 steel, the optimum hardness (775 HV0.1) and the wear resistance (1.80 mg/500 cycles), were obtained from the diffusion layer depth (252 μm) and the white layer thickness (12 μm) reached 240 min plasma nitriding of the 94% H2 + 6% N2 gas mixture.

DOI:10.12693/APhysPolA.135.786 topics: machining, plasma nitriding, tribological properties, SEM