Analysis of the tribological behavior of high carbon and high silicon steel (HC-HSi) against pins with cemented carbide substrate and cermet in pin-on-disk tests

Abstract

During the last decades, studies involving the bainitic structure have attracted researchers for combining high strength and high ductility. Bainitic steel be potentially useful in structures suffering rolling and/or sliding fatigue, e.g. rails railway, mining components, bearings and shafts. These properties have been obtained by carefully designing the alloy and an adequate austempering heat treatment. However, the material with these properties does not facilitate machinability in manufacturing processes, making it necessary to work the material in an annealed state. Therefore, this work aims to contribute to the tribological analysis of the contact between molten steel in the annealed state against carbide and cermet (coated with Titanium Nitride (TiN)), which are materials widely found in cutting tools. For this purpose, pin-on-disk (PSD) tests were carried out in order to analyze the evolution of the friction coefficient (µ), specific wear coefficient (k) and the behavior of induced deformations. The results indicated that the lowest µ values were observed using posts with cermet substrate, which suggests that it was influenced by the chemical composition of this substrate. Regarding the k and deformed layer thickness for both substrates, there was no significant variation in the values found. Smooth surfaces were observed for the tracks worn in all evaluated conditions and signs of plastic deformation (ploughing) which suggests the action of smooth abrasion mechanisms. However, it was observed that both the adhesion and the abrasion mechanism influenced the µ for the cermet substrate in the replica condition. The work contributes to evaluate the influence of different substrates and identify the wear mechanisms present.