Abstract
Exploitation properties of rails are formed by controlled heat treatment of the head of the rail carried out after rolling. Complex cooling schedules have to be applied to obtain required microstructure and properties of rail steels. Design of these cooling schedules should be supported by numerical simulation. This, however, requires advanced phase transformation models which are able to predict not only average parameters of the microstructure but also morphology of the pearlite and carbon distribution in this structural component. Therefore, numerical model of pearlitic transformation is proposed in this work. The model was based on the solution of the carbon diffusion equation. The boundary conditions were determined assuming local thermodynamic equilibrium. Location of the interface in each time step was predicted from the condition of mass conservation. The created model allowed determining of the interlamellar spacing and carbon distribution in austenite for different cooling cycles. The results of analysis can be used to predict the strength and hardness of the steel.