DEVELOPMENT OF A MATHEMATICAL MODEL FOR CALCULATING THE THERMAL FIELD AT THE INTERSECTION OF A RAILROAD RAIL DURING HEAT TREATMENT

He current technology in Ukraine, for the further improvement of thermal processing modes of rails made from steel, the chemical composition of which meets the requirements of the current DSTU 4344: 2004. Method. A sample of the investigated steel was subjected to a hardenability test by end quenching (Jominy test) (GOST 5657). The simulation of the rail's quenching was carried out using the finite element method (MKE) in the environment of the ANSYS software complex. Results. The simulation of the quenching process of the rail is the regularity of the temperature change of the metal in the process of its accelerated cooling. It is established that on the rail's rolling surface or tread, the cooling rate of the metal is quite high, namely about 12°C/s. However, at depths of more than 11 mm, the rails do not have time to cool down to temperatures of about 500-550°C, which are necessary for obtaining a fine pearlite structure. Instead, the temperature of the metal after quenching is more than 700°C, that is the steel continues to be in austenitic state. This indicates the need to adjust the methods and modes of rails' heat treatment in the direction of more intense cooling of the inner layers of the rail's head. Scientific novelty. The regularities of the temperature changing at the intersection of the rail in the process of heat treatment are established. Practical significance. This model can be used to determine the required cooling parameters in the process of thermal strengthening in order to obtain the necessary structural state and complex of properties. This, in its turn, will allow us to choose optimal modes of differentiated heat treatment to obtain the maximum homogeneous structural state and, as a consequence, the properties at the intersection of the head of the rail.