Thin slab casting and direct rolling technology (TSDR) is one of the latest trends for the steel production. Application of the TSDR enables to reduce energy consumption thus making production costs lower and the steel production more environmentally friendly. Endless Strip Production process (ESP) represents one of the TSDR types. Current study was aimed to develop a model for prediction of the microstructure evolution, precipitation kinetics and mechanical properties of the HSLA steel produced at the ESP plant. The Investigations were especially focused on the kinetics of the Nb(C,N) precipitation. The Nb-inclusions allow to control the evolution of the microstructure and to increase the strength by the precipitation hardening of the final product. As a result can be achieved the desired mechanical properties.