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A significant part of the cost of released products in the smelting of steel is the cost of graphite electrodes, so reducing their specific consumption is an urgent task. The aim of the work is to study on a computer model and analyze the efficiency of using evaporative cooling to reduce the consumption of graphite electrodes in electric arc furnaces of three-phase alternating and direct current of small capacity. A computer simulation of the thermal state and fame of graphite electrodes for arc furnaces of three-phase and direct current with the capacity of 12 tons was performed. The efficiency of using evaporative cooling of graphite electrodes was revealed. It is established that for arc furnaces operating on direct and three-phase alternating current, the use of electrodes water cooling allows to reduce the consumption of graphite by about one and a half times. It is established that the water supply to the evaporative cooling system is the most rational during 1–2 minutes after the current is turned on. The use of evaporative cooling of graphite electrodes in arc furnaces can be recommended to reduce their consumption on operating and designed small capacity alternating and direct current arc furnaces.

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The cost of the graphite electrodes amounts greater proportion in the final value of the finished product. This calls for finding opportunities to reduce the maintenance costs of AC and DC furnaces used in foundries. The aim of the study is the creation of a mathematical model and the analysis of the efficiency of the evaporative cooling method in reducing the amount of the graphite electrodes used in small capacity arc furnaces. The mathematical model and the computer program allow determining the thermal state of the electrode and the melting loss of the graphite, the model is developed for a primarily cylindrical electrode and takes into account: the current passing through an electrode, the time of the electrode being in the electrified furnace, and the parameters of the water evaporative cooling. The paper presents the received data about the melting loss of the graphite per ton of steel against the water consumption during the evaporative cooling. The graphite consumption in the arc furnaces of 10–12 tons’ capacity is reduced by 40 %. The recommended water consumption for the evaporative cooling of electrodes for all types of foundry furnaces is 0.1–0.2 m3/h.

Bimetals are in many ways substitutes for scarce metals, while they represent an independent group of materials necessary for the creation of new machines, devices and other various products. The increasing volume of production of bimetals and products made from them requires an increase in their operational characteristics and, accordingly, an increase in the quality of finished products. One of the difficult technological tasks is the connection of aluminum and its alloys with steels of various classes, since there are many problems associated with the quality of the connection of me¬tals with different properties. To improve the reliability and durability of machines and other pro¬ducts made of bimetals, it is necessary to carry out continuous quality control, and the most effective methods are non-destructive testing. Quite promising in terms of simplicity and accessibility is the method of active thermal control, in which the investigated product is subjected to pulsed thermal action by means of a source of thermal loading. The amplitude, shape and time variation of temperature signals serve as informative parameters that allow an operator or an automated system to detect certain defects and evaluate their parameters. With all the availability of pulsed thermal control, the most difficult component is associated with specialized computer programs for processing experimental data and determining the parameters of a delamination defect. The aim of the study is to create a computer model of the thermal state of a bimetallic plate in the presence of an air bubble between the layers and, through computer simulation, to determine the size of defects during active pulse thermal non-destructive testing of steel-aluminum plates. Materials and methods. When performing the work, the methods of mathematical and computer modeling were used. The created software using the development tools of the MATLAB package was based on known methods for obtaining an approximate solution to a boundary value problem on a computer using the finite difference method. Results. A mathematical model has been developed, an algorithm for solving a boundary value problem, and a computer program has been created that allows simulating a pulse thermal control to determine the parameters of a delamination defect in a bimetallic plate. Conclusion. It was found that it is more efficient to measure the temperature difference from the side where the defect is located and the multilayer plate is heated. Heating the plates from the side opposite to the defect and their further cooling showed significantly lower efficiency in terms of obtaining a useful temperature signal. It is shown that in the presence of a defect, the greater the loading heat flux and the defect size, the greater the value of the useful signal determined by the temperature difference on the measured surface.