Influence of flash temperatures on the tribological behaviour in low-speed sliding : a review

M. Kalin

Materials Science & Engineering 374 (2004) 390–397.


Tribochemical reactions always occur in dynamic and complex contact situations where the mechanical and thermal effects are acting simultaneously, and both are influencing the result. This is why different-and sometimes contradictory-assessments of the importance of thermal and mechanical effects on tribochemical reactions are reported in the literature. An indicative and interesting example is that of sliding at very low sliding speeds. Namely, at low sliding speeds the contact temperatures should be low. Therefore, the tribochemical reactions should be a consequence of the broadly prevailing mechanical factors. On the other hand, our results show that very high temperatures could occur at the asperity spot-to-spot contacts and that it could be these very high temperatures that are mainly responsible for the tribochemical reactions and various phase transformations, even under very low-speed conditions. However, the possibilities for determining the contact temperature and obtaining the reliable evidence are rather limited and their accuracy is suspect. In this paper, we discuss various possibilities for determining the contact temperatures and point out the difficulties and uncertainties related to these techniques, particularly when it comes to defining the temperature at the asperity contacts. Accordingly, we suggest that several independent techniques for determination of the maximum contact temperature should be used to increase the reliability of the interpretation of the results.

Keywords: flash temperature, wear, friction, tribochemistry, temperature calculation, temperature measurement


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