An Experimental Study of Thermoelastic Effects in Scuffing Failure of Sliding Lubricated Contacts

Abstract

The thermoelastic instability theory of scuffing failure in elliptic contact between two sliding surfaces, developed by Johnson, Dow, and Zhang, was tested experimentally on a disk machine. The theoretical model predicts a boundary, beyond which scuffing failure is expected to occur, that depends upon contact load, sliding speed, coefficient of friction, geometrical parameters, and thermal and material properties of the contact surfaces. Experiments were performed using three contact lubricants of different viscosity, and two steels with different thermal and material properties. Results correlate with the model in the regime of high calculated specific film thickness (λ≥4) and for the two steels tested. The model as stated fails to predict scuffing failure in a regime of low calculated specific film thickness (λ≤1.3). The experimental results did not answer the question of whether there is a difference in the scuffing boundaries of the two steels tested. A time dependency to failure was observed in the regime of high specific film thickness and some indication of moving ‘hot spots’ was observed.