Dynamic modelling of the thermal space of the metallurgical walking beams furnaces

The aim of the paper is to establish the basics of a model in order to help the evaluation of the parameters of the heat transfer and energy consumption in the case of the walking beam furnaces for rolling mills. The heating process of alloyed and high-alloyed steel billets in view of processing by rolling is analyzed. The temperature gradients, producing internal thermal stresses in the heated material, are a problem that influences the design of the aggregate. If the values of the thermal stresses exceed the tensile strength they can lead to the destruction of the finished product. The thermal stresses are mostly due to the poor correlation of heating process of the billets in typical furnaces for rolling mills with mechanical and thermal characteristics of the heated material and with the dynamic of the gases. Using physical and mathematical modelling, there are established correlations between the thermal process, the dynamic of the gases and the particularities of the furnace in order to obtain the conditions for modelling a variable geometry of the aggregate. The particularities of the steels and of the furnace are analyzed in order to reach an optimum of the geometrical model for the thermal space. Physical and mathematical models are used to establish a new variable geometry. Saving energy and metal, due to the chemical, thermal and dynamic processes, means having a cleaner environment. A new disposal system of the burners inside the furnace and a new variable geometry of the thermal space can lead to energy and metal savings. The conclusions of the study are applied for a new design of the furnace, including dynamic aspects of the geometry of thermal space.