Are types of the polyterm of kinematic viscosity of industrial steels and their conditions of emergence in the experiment. It is shown that heating of the melt above the critical temperature leads to the branching polyterm. Politerm properties of multicomponent melts sharply different from polyterm pure metals. They are almost never monotone, and even more linear. For each type of alloy the temperature dependence of the properties have their own distinctive look with the peculiarities caused by the composition of source materials and production specifics. Given the anomalous temperature plots temperature dependences of kinematic viscosity and critical temperature. Revealed a significant role of carbon in the formation of the structure not only solid but also liquid states. Shows the role of the main alloying elements. Among the main alloying elements chromium highlights, providing an ambiguous impact on type polyterm viscosity depending on the carbon content of the steel. The increase in the concentration of chromium in low- and medium-carbon steels leads to the disappearance of anomalies in poyiterm heating, and high-carbon steels on the contrary - to a more prominent manifestation. This can be explained by the fact that chromium in low and medium carbon steels it manifests itself mostly as an element that legeret matrix and contributes to reconstruction of her lattice in the BCC structure. For some steels and alloys, for example, with a high content of manganese, has had a negative hysteresis of the viscosity, i.e. the branch is below the cooling branch of the heat. The influence of oxygen and nitrogen on the temperature dependences of viscosity. So when the concentration of these elements the critical temperature is shifted to higher values. Technology of termotime-preparation has been presented the pig iron improves the efficiency of the modification and saves the modifiers.