Differential heat treatment of rails by means of rolling heat

Resumo

Differential heat treatment of rails by air on the basis of the rolling heat is considered. The research is conducted at AO EVRAZ ZSMK during the reconstruction of rail production. The influence of the chemical composition of the steel and the conditions of plastic deformation and heat treatment on the onset of polymorphic transition is studied. Thermokinetic diagrams are plotted for steels of experimental chemical composition. The cooling rate over the cross section of the rail head is investigated as a function of the heat-treatment parameters. The optimal chemical composition and heat-treatment conditions are determined. The heat treatment of rail samples directly after rolling is experimentally studied. Recommendations for the industrial introduction of differential quenching are developed on the basis of the theoretical and laboratory results. Industrial tests show that the rails produced are of high quality and comply with standard requirements.