Kinetika teplotního pole při ochlazování kolejnic

Abstract

The current development is characterized by requiring higher quality of the products. The materials should withstand higher loads, have longer working life and ensure safe operation of the system. This current trend is also for the production of rails. Rail transport requires an increase in operating speeds and loads, which raises the demands on the properties of the rails. The rail as the main part of the railway track serves to support and guide the rail vehicle. The stress on the wheel - rail contact reach values up to 2000 MPa. The rail steel must be hard, wear-resistant and tough due to stress and load. The main way to improve the mechanical properties of the rails is to control the microstructure of the material. It is necessary to know the influence of the kinetics of the temperature field on the structure in order to actively control the temperature deformation mode in rail production. This thesis “Temperature field kinetics during cooling of rails“ deals with the solution of the temperature field kinetics in the cooling of the rails. It describes the possibilities and current trends of production and subsequent heat treatment. An analysis of this problem shows the need for knowledge of the distribution of temperatures. Furthermore, the thesis deals with the solution of the temperature field of the cooled rail, finding the optimal solution method and determining the boundary conditions. The experimental part describes the method of measuring the cooling curves. From the measured values, the heat transfer coefficient was determined by the inverse task, respectively boundary conditions. To verify the specified boundary conditions, a cooling model was created in the program Sysweld.