A phenomenological model of the third body particles circulation in a high temperature contact

International audienceIn high temperature forming processes (forging, rolling, die-casting...) the tool surfaces are the privileged places for mechanical, thermal and physico-chemical solicitations. More precisely, friction and wear play an important part in tool surface damage. The tool steel grades exhibit damages such as local plastic deformation, plastic flow, carbides fragmentation and oxidation. Oxide scales, which depend on the contact temperature, influence wear mechanisms and have to be considered in the wear model development. The aim of this work is to assess the third body particles circulation in a high temperature friction contact. The wear investigations are carried out using a high-temperature pin-on-disc tribometer. The pin is made of X38CrMoV5 steel (AISI H11) and the disc is made of common steel (C38, AISI 1035). The setting temperature is 900 °C. All experiments are performed under constant load and velocity. The special design of the pin surface contributes to the trapping of third body particles and to the identification of the third body flows. Environmental Scanning Electron Microscopy (ESEM, in ambient air) observations and Energy Dispersive Spectrometry (EDS) investigations have revealed that different types of third body particles circulate in the contact. Based on these observations and chemical analyses, a phenomenological model of the third body particles circulation in a high temperature contact is proposed, based on the third body concept approach