About the Efficiency of Using Modern Technologies for the Formation of Hardened Coatings from Self-Fluxing Alloys in Combination of Gas Thermal Spraying and High-Frequency Current Melting

Abstract

A comparison is made of the characteristics studied in recent years in the CIS and other countries and relevant for the industry processes of forming wear-resistant coatings from self-fluxing alloys on metal products using a combination of gas-thermal (plasma, flame) spraying and high-frequency induction (HF) melting. A preliminary analysis of the parameters of this type of process is performed using various types of melting of coatings containing (after spraying) the strengthening ceramic (carbide, boride , oxide) or other phases that have been experimentally tested at the present stage. The prospects for using devices for melting that provide increased energy efficiency during HF treatment are revealed. Taking this into account, an experimental study was conducted with the measurement of the mode parameters of the high-frequency current inductor affecting the properties and quality of the melted surfaces obtained on cylindrical samples of ferritic steel wear-resistant coatings based on the PR-NH17SR4 self-fluxing alloy sprayed by the gas-flame method on nickel. It was shown that, using this hybrid technology, in particular, at an inductor power of 80–100 kW and a field frequency of 53 kHz, it is possible to obtain wear-resistant coatings, moreover, dispersion-hardened, as is assumed, due to microinclusions of phases of borides, silicides, and carbides of chromium and iron crystallizing in the metal matrix, with a sufficiently high level of microhardness of the melted layers (≥60 HRC) with a thickness of up to 750 μm and higher, and not containing cracks in the melted coating. Specific energy consumption achieved in the tested version of coating formation on steel parts using high-frequency melting are still somewhat higher than the level (about 4–5 kWh per 1 m² of coating) demonstrated in recent years in a number of studies (in particular in the Russian Federation).