| The pump guide bearing is a core part of the pump,it's directly related to the level of operational effectiveness,energy efficiency and the service life of the pump.With the develop tendency of a large size and more precision of the pump,the unbalanced radial force of rotor parts is gradually increased and run-out reduced,it promote the requirements of a large to carrying capacity,better antifriction performance,wear resistance,corrosion resistance and lubricating water-film reliability of the material for water lubricated bearings.This article attempts to develop a new kind of POM-based wear-resistant composites for the pump guide bearing,and the mechanical property,carrying capacity,tribological property and wear mechanism were measured by relevant instruments and equipments.The contents and main conclusions are as follows:1)The PTW/POM and PTFE/PTW/POM composites were prepared through melt extrusion and injection molding,and the influence of PTW and PTFE on the composites' mechanical property and tribological property was studied.The results showed that:The tensile strength and flexural strength were improved with adding an appropriate amount of PTW in the composites,and the tribological properties were improved when adding 10 wt%PTFE in the composites.When the contents of PTW and PTFE was 10wt%in the composites,the comprehensive properties of the composites is the best.2)The tribological properties of the composites are closely related to the friction media and the materials of friction pair.When 3Crl3?45 steel and Grl5 were used as the materials of friction pair,the friction coefficient and wear loss with the 45 steel friction pair are the least.When water,20th oil and 5%sandy water are used as the friction media,the friction coefficient and wear loss in the No.20 oil are the least.The friction coefficient in 5%sandy water is 2.4 times of water,7.3 times that of the oil,the wear loss in 5%sandy water is 17.5 times of water,7.3 times that of the oil.3)Through the worn surface of SEM analysis showed that:The wear mechanism were different when the friction media were different,in water-based adhesive wear,in the oil also showed a slight adhesive wear,and in 5%of water was manifested in sandy plastic deformation and fracture of plastic.4)The PV limiting value of POM and PTFE/PTW/POM composites were tested by the pin on disc wear device and ring-ring wear device.When continuous loading on the pin on disc wear device,the PV limiting value of POM is 310.5(N·m/s),and the that of PTFE/PTW/POM composites is 1898.5(N·m/s).In this kind of loading conditions,the friction coefficient's trend of POM and PTFE/PTW/POM composites is different,the former is cyclical upward trend,while the overall downward trend in the latter,it is related to composition of materials,whether to generate boundary wear and three-body wear.When continuous loading on the ring-ring wear device,the PV limiting value of POM is 109.9(N·m/s),and that of PTFE/PTW/POM composites is 219.8(N·m/s).In this kind of loading conditions,the friction coefficient's trend of POM and PTFE/PTW/POM composites were similar,it tended to decrease,but the value of friction coefficient for the latter is smaller and fluctuation range narrower under a higher load,it is related to the adding of PTFE that caused transfer film lubrication.5)Having excellent overall properties,the PTFE/PTW/POM composites could be considered to be used as the materials of pump guide bearing. |
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