Thermostating of a continuous-cast ingot in a continuous casting machine to provide direct rolling

The paper describes mathematical modeling of the temperature field of a continuously cast cast ingot with a zone of thermal insulation in a two-dimensional spatial representation to ensure direct rolling. Currently, the cooling and solidification modes of a continuous cast ingot do not ensure an even distribution of temperatures across its cross-section, the difference between the surface and the center at the exit from the caster at different drawing speeds can be up to 500 °С. In order to maintain the heat of the melt and to ensure an even distribution of temperatures over the ingot section, it is proposed to use thermal insulation instead of air cooling in the air-cooled zone of the continuous casting machine, which will reduce (or eliminate) the intermediate heating of the ingot in heating furnaces before rolling. A mathematical model of the cooling of a continuously cast ingot is described, taking into account the evolution of the heat of crystallization in a two-phase zone and the equalization of the temperature along its cross section. The numerical realization of the model was carried out by the method of splitting by coordinates in the programming language C++. The adequacy of the model was verified by the convergence of the calculated and experimental data. To estimate the temperature equalization by its cross-section, a numerical experiment was conducted in the thermal insulation zone, as a result of which a temperature field of a continuously cast ingot along the length of the continuous casting machine was obtained at casting speeds of 0.6 to 1.4 m/min. The efficiency of temperature equalization over the section of the ingot was determined when using the heat insulation zone in comparison with air cooling. Based on the simulation results, it is established that the heat content of the ingot due to the use of the heat of the liquid phase is increased by ~ 30%, which makes it possible to apply direct rolling.