IMPROVING THE WEAR RESISTANCE OF PARTS WITH ELECTROMECHANICAL SURFACE HARDENING

The hardening of parts made of steel and cast iron by electromechanical surface treatment is one of the effective technologies for hardening the important surfaces of products with concentrated energy flows. The paper presents the results of comparative wear tests of steel 38Х2МЮА samples after hardening of their outer diameter by concentrated energy flows by nitriding and electromechanical surface hardening (EMSH). The test duration was 60, 120, 240 and 480 seconds. Nitriding was carried out for 18 hours at a temperature of 550ºС. EMSH of cylindrical shaped samples was carried out at a temperature of 1000...1100°C in the “tool-surface” contact zone and an optimum force was 400 N in the contact zone of the instrument and samples. Comparative tests of the wear resistance of the treated surface of the samples were carried out on a friction machine according to the method of the American Society for Testing and Materials (ASTM G65). The results of the wear tests of the samples indicate a high efficiency of the technology as compared to the original samples: the wear rate of the samples for 240 s of tests by nitriding was 3.8 mg/min, and after the EMSH - 4.8 mg/min; for the period of tests 240-480 with the wear intensity of the samples by nitriding was 2.6 mg/min, and after the EMSH – 2.55 mg/min. The practical significance of the research is connected with a possibility of replacing the nitriding process with a less expensive technology. The effectiveness of the electromechanical surface hardening technology is associated with a possibility of implementing the method on metal-cutting machines with the formation of high quality indicators for the surface layer of parts in terms of hardness, metal structure and the depth of hardening. The implementation of research results allows the use of electromechanical surface hardening in the manufacturing and restoration of shafts, sleeves, gear wheels, gear shafts and other farm machinery parts in mechanical repair shops.