“An Overview on the Tribological Behaviour of Nitro-Carburised Steels for Various Industrial Applications”, Tribology in Industry, 37, No. 3, 2015, 299-308.
The present study is focused on elucidating the wear mechanisms taking place during sliding friction
of five (5) steel grades subjected to Trufftriding. For this purpose, three sliding friction experimental
configurations were used and the friction coefficients, real-time-recorded during testing, were
correlated to the post-testing microscopic observations of the worn surfaces. Finally, the
experimental findings were evaluated with respect to the initial microstructure of the tool steels in
their as-received and/or heat-treated state. In the case of non-conformal point contact against
ceramic counterbodies, the friction coefficient was found to depend only on the steel grade and the
particular counterbody, tending to a constant value, regardless of the applied load and/or its heat- or
surface treatment. In the case of conformal plane contact against hardened steel, each steel grade
exhibited an applied pressure range within which the wear coefficient remains practically constant,
whereas for higher pressure values, seizure occurred. Nitrocarburising “displaced” the constant wear
coefficient range towards higher pressure values, resulting in seizure retardation.