Zakharova I. Theoretical and technological basics of resource and energy saving at arc spraying with the use of pulsating spraying air flows

The objective of the research – scientific substantiation and development of resource- and energy-saving technology of arc spraying using a pulsating supply of spraying airflow. The object of the research is the processes of formation of spraying airflow and transfer of electrode liquid metal particles during arc spraying. The subject of research – effect of pulsating spraying airflow on technological parameters and qualitative characteristics of the sprayed layer. Research methods: mathematical modeling using software, mathematical packages of Microsoft Excel, MathCad, Ansys-ED, experimental studies of microstructure, microhardness; abrasive wear; shadow photography. Results of the research: The principle of arc spraying using pulsating air supply into the electrode melting zone, which allows to minimize the negative effect of oxygen on the chemical composition of coatings and reduce energy consumption for the process, was theoretically proven. For the first time, pulsating spraying airflow in arc spraying technology was proposed, which provides a 20-30% reduction in the loss of alloying elements of sprayed electrodes (in absolute content) and improves the performance properties of coatings. A mathematical model of melting, formation, and separation of liquid metal in the form of spherical and semi-ellipsoid droplets from the ends of electrodes using pulsating flow has been developed. A mathematical model for calculating residual stresses in the sprayed gas-thermal coating has been proposed. The uneven distribution of stresses over coating thickness with the maximum value in the transition zone has been revealed using it. Implementation of results of dissertation in production at industrial enterprises of Ukraine provided a reduction of material consumption by 42%, productivity growth by 26%, an increase of coating adhesion strength with the substrate by 22%, increase of sprayed products operating resistance by 25%. The total economic effect from the introduction amounted to 2,202 mln UAH.