The presented results demonstrate the possibility of mathematical complex model in research of the temperature characteristics pattern changes in polymorphic transformations, isotherms of liquidus and solidus, and other parameters depending on the cooling conditions of the ingot. Shown the possibility of predicting parameters of a continuous ingot microstructure (distance between dendrites, size of the austenite and ferrite grains). Were made microstructure parameter calculations of the continuous steel ignot containing 0.17% C, 0,62% Si, 1,4% Mn at various secondary cooling modes.