The polytherms of the properties of multicomponent melts differ significantly from polythermal pure metals. They are almost never monotonous, let alone linear. For each grade of alloy (steel), the temperature dependences have their own characteristic appearance with features caused by the composition, the raw materials used in their manufacture, and also the specificity of production. For the first time in the conditions of JSC "Vyksunsky Metallurgical Plant" an experimental work was carried out to study the physical properties and structure of tubular steels near the phase transition. The temperature dependences of the structure-sensitive properties of iron-based liquid alloys are studied. The polytherm of heating revealed special points and areas. All the polyterms constructed are characterized by a mismatch between the heating and cooling branches (hysteresis), which indicates a disequilibrium in the structure of the samples after their melting. Heating the system to temperatures tan ensures the presence of stable hysteresis and indicates a multi-stage transition to equilibrium. As a result of the work, new experimental data were obtained on the physical properties of carbonaceous melts on the basis of industrial pipe steel grades (steel grade 22GYU) produced in electric arc furnaces. The influence of charge materials on the physical properties of melts has been studied. The kinematic viscosity and surface tension of industrial melts of iron-based pipe grades in the temperature range from the liquidus with an excess of 100-200 °C were measured. As a result of the experiment, polytherms obtained by measuring the kinematic viscosity and surface tension on samples of two melts have been constructed and given for visual comparison using various types of charge materials. To test the results, another 20 samples were analyzed from real melts, smelted in accordance with the current orders in the casting and rolling complex. Based on the experimental data obtained, the following recommendations were issued: maximum heating in the EAF furnace to a temperature of 1670 °С, holding for 5-10 minutes for homogenization of the melt, output of melting from the furnace. Recommendations are given on the further temperature preparation of melts of pipe marks on the basis of iron. At the same time, the issue of the resistance of the refractory lining of steel casting ladles is of particular importance in connection with higher temperatures of melting from an arc furnace.