OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 Fig. 9. Influence of the counterbody roughness on the coefficient of friction of Maslyanyt 12 However, many factors influence the hydrodynamic friction effect: specific pressure, sliding speed, medium viscosity, etc., the optimum of which is difficult to ensure not only in real practice, but also at the research stage, which is confirmed by these studies. As a result, increased wear of the polymer composition prevails during the running-in and micro running-in period due to the cutting action of the bronze surface microasperities. A film of macromolecules of polyamide, bronze decomposition and iron minium formed in the initial period of friction because of tribodestruction are preserved in the surface deformable layers of the composite and on the working surface of the counterbody. The positive tendency to reduce wear and friction with an increase in the grade of surface finish can be explained by a softer smoothing of the small microasperities of the counterbody, faster running-in, lapping of working surfaces and, therefore, the early steady-state wear process and the “self-organization” of the tribosystem. Bench tests in seawater The tests were performed near Sochi (Lazarevskoye). Since significant heating of the material may occur during friction due to the low thermal conductivity of plastics and heat removal from the friction zone, mainly only through a metal counterbody, and also considering that in addition to the load from the transmitted working force the units of real sea vessels and deep-sea equipment also experience water pressure, it was necessary to conduct tests as close as possible to real operational conditions. A bench of deep-sea field tests was created to conduct these studies. This test bench represented a chamber into which sea water was supplied using a high-pressure pump (up to 200 atm.). Bronze (9 % Al; 2 % Mn) and Maslyanit 12 were chosen as friction pair materials for comparison of laboratory and bench results. The test samples were in the form of ø 80×50×26 half-liners (Figure 10) and internal grooves to provide continuous access of the lubricant – sea water – to the friction zone. To relieve internal stresses, samples made by injection molding were heat treated in Vapor oil. Prior to testing, the samples were kept in sea water for 24 hours. The tests were performed at a specific load of 2.5 MPa and a sliding speed of 0.3 m/s. The measurements were taken every 3 hours during running-in and 50 hours after the steady-state wear. The total duration of the test was 670 hours. Measurement points were marked according to the template. The period of friction running-in lasted 72 hours, after which the wear rate was set at 0.5–0.8 μm/h. As a result of visual inspection and measurements of samples performed at the end of the tests (average wear
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