Study of operational properties of steel friction pairs with antifriction coating from copper alloys produced by electric spark alloying

Abstract

Improving the reliability, durability and safety of operation of heavily loaded friction units is an urgent problem in physics, chemistry and surface mechanics. The tribotechnical characteristics of coatings made of bronzes BrAZhMts10-3-1.5 and BrMtsF3-6, applied by electrospark alloying on bushings made of structural steel 30KhGSN2A for operation under conditions of high contact pressure under friction without lubrication, have been investigated. Modes of coating deposition from the standpoint of tribology (the value of the electric discharge current in a pulse, the value of the longitudinal electrode feed per one rotation of the part, the rotation speed of the workpiece, the number of passes during processing, finishing of the coating) have been developed. It was found that when applying bronze BrMtsF3-6 to obtain a high-quality coating, the process must be performed in a protective atmosphere of argon to prevent phosphorus burnout. The tribotechnical efficiency of coatings when working under dry friction conditions is shown. For the steady-state wear mode, the friction coefficient is 0.10 – 0.13 at a pressure of 200 – 250 MPa, the wear resistance of coated steel is doubled. Steel with a bronze coating BrAZhMts10-3-1.5 has a higher bearing capacity, with BrMtsF3-6 coating — a higher antifriction. The ways of increasing the service life of steel-coated steel friction pair are analyzed.