Инженерные технологии и системы (Jun 2019)
Modelling the Temperature Field of a Surface in Using Electrospark Alloying of Metals
Abstract
Introduction. At present, the problem of increasing performance properties of machine parts, tools and tooling by improving the physical, chemical and mechanical characteristics of their executive working surfaces is relevant. One of the modern methods of obtaining coatings on the surfaces of parts is the method of electrospark alloying. In the case of electrospark alloying, it is important to select the thermophysical properties of materials to obtain coatings with desired physicomechanical and tribological properties. The paper presents the results of the method development for calculating the unsteady temperature field of the processed material (cathode) having the form of a rectangular parallelepiped, on one side of which a doped layer is formed during electrospark alloying. Materials and Methods. To form doped layers in a drop-shaped electro-mass transfer, we used iron in the form of a parallelepiped as a being processed material (cathode) and tungsten was used as a processing material (anode). A nonlinear initial boundary value problem and a computational scheme are suggested for determining the temperature at all points (temperature field) of the cathode made in the form of a parallelepiped with the location of several heat-emitting drops on its face. Results. The paper presents an algorithm for solving the problem by the second Green’s formula of finding the temperature field in the cathode made in the form of a parallelepiped, in this case the described nonlinear model of the flow from droplets to the parallelepiped is replaced by a linear model. An algorithm is constructed and calculations are carried out to determine the temperature values at all points and the temperature flow in the cathode in the case of one average drop on its face. According to this algorithm, a software package was created and experimental calculations were carried out. The dynamics of temperature values at all points and the heat flux of the cathode points under study is shown. Discussion and Conclusion. To achieve higher coating properties and a greater efficiency of the electrospark alloying, it is necessary to calculate the temperature field and heat flow of the cathode points under studying. The proposed mathematical model is calculated for the case of one drop placed on the boundary of a heat-conducting half-space. When choosing an anode material depending on the erosion resistance to obtain the required thickness of the surface layers with the specified functional properties, the developed calculation method is used, which allows us to describe the cooling process of one drop and then use this information to average the description of the effect of heating the parallelepiped body by a number of such drops.
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