Coating of Carbide Steels on a Steel Base by Plasma Spraying

Abstract

Purpose. Establish the possibility of using the method of plasma spraying of coatings from carbide steels on the steel base in order to increase wear resistance, to identify modes of spraying and to investigate the properties of the resulting coatings.Methods. Carbide steel has been obtained by mixing the components of steel and titanium carbide in a hard-alloy ball mill in alcohol (0.25 l per 1 kg of mixture) for 48 hours with a ball and mixture ratio of 3 to 1. The mixing mode was established during the previous work at the department. After mixing, it was dried at 80-100 °C in the drying chamber.The granulometric composition was determined on the FRITSCH ANALYSETTE 22 MicroTec plus universal laser device, equipped with a liquid dispersion unit. Fluidity measured according to GOST 20899-98. Bulk density was measured according to GOST 19440-94.Results. The analysis and classification of methods of surface treatment of parts and tools of various purposes was carried out, the most common and promising methods for restoration of products were identified, which include methods of spray coating, vacuum metallization and electrophoretic deposition. The process of plasma spraying of coatings from carbide steels on the basis of carbon steel 45 was studied. The possibility of using the method of plasma spraying of coatings from different types of carbide steels on the steel base in order to increase wear resistance was established. The method of preparation of powder mixture by melting in the hydrogen atmosphere which ensures sufficient fluidityof carbide steels during the formation of coatings was studied. Optimal modes of coatings were established.Conclusion. The conducted analysis and classification of methods of surface treatment of parts revealed the most common and promising methods, among which the process of plasma spraying of coatings was noted. Experimental studies have shown not only the possibility of practical application, but also a positive result. The high strength of adhesion of coatings with the base metal after vacuum sintering (For 10% TiC carbide steels and base of Cr6W3Mo steel - 116 MPa, for the 40% TiC carbide steels and base of Cr12Mo steel - 220 MPa) has been established.