Effects of lubrication, specimen preparation and tool coating on the friction behavior of commercially pure titanium at elevated temperature

Roszak, Jacob Aleksander and Rosochowski, Andrzej and Rosochowska, Malgorzata; (2021) Effects of lubrication, specimen preparation and tool coating on the friction behavior of commercially pure titanium at elevated temperature. In: 24th International Conference on Material Forming. Université de Liège, BEL. ISBN 9782870190036

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    Abstract

    Titanium forming processes are often limited by severe adhesive wear as a result of poor friction conditions. This can be partially remedied with careful selection of lubricant, billet preparation and tool coating, but the optimal combination of these factors is not known. A full factorial ring compression experiment, with grade 2 commercially pure titanium rings deformed at 300 °C, was conducted to study the effect of each of these factors over three levels. The change in internal diameter was compared to a set of calibration curves generated by an FEA simulation of the process in order to determine the friction coefficient during each trial. A robust statistical analysis methodology was used to isolate and evaluate the effect of varying each factor. The choice of lubricant was found to be the most statistically significant factor by a considerable margin, followed by the method of billet preparation, with tool coating found to be insignificant. Of the lubricants tested, the graphite-based lubricant resulted in the lowest friction, followed by the WS2- and MoS2-based lubricants. Sandblasted billet surfaces resulted in similar friction to as-machined surfaces, whereas those subjected to micro-arc oxidation performed notably worse. For reducing friction during warm forming of titanium, a graphite-based lubricant is therefore recommended, with tool coating and billet surface preparation unlikely to provide significant further improvement.

    ORCID iDs

    Roszak, Jacob Aleksander ORCID logoORCID: https://orcid.org/0000-0003-4757-2391, Rosochowski, Andrzej ORCID logoORCID: https://orcid.org/0000-0001-7896-8167 and Rosochowska, Malgorzata ORCID logoORCID: https://orcid.org/0000-0001-5560-6024;