An Assessment of Surface Temperature Predictions in the High Speed Sliding of Unlubricated SAE 1113 Steel Surfaces

The paper examines the influence of temperature-dependent physical properties on the total temperatures predicted in the high-speed sliding of unlubricated SAE 1113 steel surfaces. The calculations are based on experimentally determined subsurface temperatures, friction coefficients and available temperature-dependent physical properties. It is shown that predictions based on two different asperity models are never more than 60 C different. The Jaeger-Archard theory is modified to account for differences in subsurface temperature of the two bodies. The modified theory is used to show that the predicted total temperature is relatively insensitive to differences of about 15 percent in subsurface temperature. Under these circumstances, if the subsurface temperatures are assumed equal, the predicted total temperature is the maximum value attainable. Interpretation of the theory in the case where there are multiple junctions between the surfaces shows that for subsurface temperatures < 600 C the total temperature attained is sensitive to the number of contacts within the range 1 to 100. For a greater number of contacts or for conditions under which the subsurface temperature exceeds 600 C, there is only a small influence on the total temperature.