Selecting the Technological Parameters of Steel Coatings Formation by Hypersonic Metallization

Abstract

The main idea of the article is to generalize the results of studies of the formation of the steel coatings produced by Hypersonic metallization, defining rational modes of recovery and hardening of transport machinery and technological equipment technologies. To achieve this goals the installation of hypersonic metallization model ADM-10 was used, sprayed materials - steel wire 95H18SH (AISI 440-C) and 40H13 (AISI 420). To increase the adhesive strength of coatings with the substrate an intermediate layer of an alloy H20N80 was coated. The studies revealed that increasing of initial temperature of spraying gas enhances the aerodynamic forces acting on a particle of the molten metal. Increasing of the nozzle radius enhances the maximum speed of the particles by extending the distance of dispersing. Activation process of the electric arc metallization by heating of the atomizing gas allows to increase the speed of the particles smaller than 40 microns, essentially without effect on the speed of the larger particles. Studying of density and adhesion of deposited coatings showed that if the spraying distance increases more than on 200 mm and over, the porosity increases sharply, and the bonding strength decreases. Therefore advisable to limit spraying gas temperature and pressure at combustion chamber of the Hypersonic metallization installation to the size of 2 300-2 500 K and 0,6-0,8 MPa respectively. Amount of oxygen in the coating at hypersonic metallization is 1,5-2,0 times less in comparison with the traditional method of electric metallizing. parameters of the hypersonic metallization process and displacement speed of the metalizer which provide quality coatings spray wires of steel alloys were defined.

Keywords

• steel coatings
• hypersonic metallization
• porosity
• coating properties