The analysis of the process of separation of liquid metal from the electrode ends at arc metallization within the conditions of a pulsating spraying flow

Abstract

Among the resource-saving technologies, the method of gas-thermal spraying of coatings, namely arc metallization, is being developed intensively. The current state of research does not fully reflect the physical and chemical processes that occur during arc metallization, which does not allow to improve the technology and equipment for this method, to predict and influence the chemical composition and properties of coatings. The main problem that arises when parts are restored by the arc metallization method is to improve the quality of coatings by reducing the negative impact of oxygen in the spraying airflow. To reduce the oxidizing effect of air-spraying flow on the liquid metal of electrodes the method of arc metallization utilizing the pulsating spraying flow, obtained by introducing an additional element ­– a valve of the pulsator into the spray system of electroarcmetallizer, was previously introduced. The nature of forces acting on the liquid metal of electrodes at melting by an electric arc without consideration of spraying flow is reviewed. Taking into account the findings presented in the works of V.I. Dyatlov, B.E. Paton, a diagram of liquid metal formation on the cathode and anode depending on the parameters of the electric arc mode without considering the impact of the spraying flow is presented. Under the impact of a pulsating spraying flow, a drop of molten metal of the electrodes will turn into a half-ellipsoid shape. The impact and distribution of forces acting on a drop of such shape and conditions of separation of a drop from the electrode ends are important. Analytical calculation of forces acting on a drop of semi-ellipsoid form during arc metallization with a pulsating spraying flow was carried out in this paper