The degree of breakdown of the cemented and borated surfaces on details of the cutting pair of the hydromechanical slot perforator

In connection with the intensification of the operation of machines and mechanisms, elevated temperatures and pressures of the surfaces increases significantly. In terms of contact loading in all types of wear parts and machine components fail not due to failures, but because of an unacceptable change in size and shape, as always wear occurs on the surface. In this connection, the structural state and geometric characteristics of the working surfaces of machines and mechanisms play a crucial role in ensuring its reliability and durability. The condition of the surface of the cutting pair knives and axles of hydromechanical slot perforator designed for the opening of boreholes in order to increase their useful life is investigated. A strengthening thermochemical treatment of the surface layers of steel 18HGT, U8, 4H5MFS, 6H6V3MFS is studied. Three friction pairs after the same operating conditions are investigated. The first cutting pair is presented by the axle of mild structural steel 18HGT after cementation and knife of carbon steel U8 with diffusion boride coatings. The second cutting pair is presented by the axle of steel 4H5MFS and knife of steel 6H6V3MFS with the diffusion boride coating. The third cutting pair is presented by the knife made of steel 6H6V3MFS and the axle made of steel 4H5MFS after a full cycle of strengthening treatment (diffusion borating, quenching and tempering). It is shown that the degradation of the boride coating on carbon tool steel takes place in response to the development of oxidative processes. The service life of cemented axles is determined by the thickness of the hardened layer. Maximum durability have boride coatings on axles made of steel 4H5MFS and knives made of steel 6H6V3MFS. In this case, the chromium boride doping of the bases leads to increased heat resistance and ductility of the protective layer that ensures high durability. It is shown that diffusion borating with a full cycle of strengthening treatment (quenching and tempering) is the best way to strengthen a cutting pair of hydromechanical slot perforator.

coatings, borides, microhardness, plastic deformation, diffusion