Computer Prediction in Optimizing the Plasma Quenching of Locomotive Wheels

Abstract

Computer software is developed for predicting the basic thermal characteristics in the plasma treatment of wheel rims for locomotives: the temperature, cooling rates, heat-flux density, and thickness of the martensitic layer at the wheel’s working surface. To verify the validity of this software, the results obtained are compared with thermometer readings and metallurgical data for the thickness of the martensitic layer. Two new features of the thermophysical model are the specification of the heat-transfer parameters in the plasma flare so as to ensure strengthening of the metal at the wheel rim by micromelting; and the ability to use the predicted temperatures and cooling rates in precision estimates of the martensitic-layer thickness. Estimates of the short-term thermal stress at the rim’s working surface show that compressive stress predominates. That is consistent with experimental data regarding the residual stress in steel samples after plasma treatment. If the proposed computer model is used in determining optimal conditions for the plasma quenching of locomotive wheels, the expenditures of time and material resources will be less than in in purely empirical selection of the operating conditions.