The role of the thermal conductivity of steel in quantitative elastohydrodynamic friction

Abstract Numerical models for thermal elastohydrodynamic lubricated contacts of steel surfaces have always employed a value for the thermal conductivity of steel corresponding to its soft annealed alloy state. However, steel in elastohydrodynamic lubricated contacts is usually hardened. It has been known for more than a century now (not within the Tribology community though) that the thermal conductivity of steel could be reduced by a factor of more than two when it is hardened. Only recently did the Tribology community realize this “mistake”, of which the impact on friction predictions is investigated in this work. The mistake is found to lead to significant overestimations of friction in the thermo-viscous regime.