Papers by Author: Yong Zhen Zhang

Abstract: The influence of DC steady magnetic field on dry-sliding Friction and wear characteristics of friction pair of high-speed steel (HSS) ring and 2Cr13 pin is studied by use of improved MPV-1500 type Friction and wear tester under normal temperature. Experiments show that, The wear loss of both HSS ring and 2Cr13 pin decreases gradually, along with the enhancement of the magnetic field intensity, under the load of 250N and the friction velocity of 0.6m/s; The phenomenon of negative wear loss appears to the HSS ring. The wear loss of the sample HSS ring keeps low comparing with that of the sample 2Cr13 stainless steel pin; The trend of friction coefficients decreases quickly and then slowly; Magnetic field can accelerate oxidization.

Abstract: The influence of DC steady magnetic field on dry-sliding friction and wear characteristics of friction pair of high-speed steel (HSS) ring / Ti6Al4V pin is studied by use of improved MPV-1500 type under normal temperature. It is shown that the wear loss of ferromagnetic materials can be decreased by applying a steady magnetic field. Under the load of 250N and the friction velocity of 0.6m/s, the wear loss of the sample HSS ring keeps decreasing along with the enhancement of magnetic field intensity, and in the scope of 64mT-160mT, the average friction coefficient becomes smaller and smaller. Magnetic field can accelerate debris refinement. The wear mechanism covers oxidative wear and adhesive wear mainly.

Abstract: The influence of DC steady magnetic field on dry-sliding Friction and wear characteristics of friction pair of high-speed steel (HSS) ring and 40CrMoA pin is studied by use of improved MPV-1500 type Friction and wear tester under normal temperature. Experiments show that, The wear loss of both HSS ring and 40CrMoA pin decreases gradually, along with the enhancement of the magnetic field intensity, under the load of 250N and the friction velocity of 0.6m/s; The wear loss of the sample HSS ring keeps low comparing with that of the sample 40CrMoA steel pin; The trend of friction coefficients decreases quickly and then slowly; Magnetic field can accelerate oxidization; Oxidation and adhesion occur mainly in friction surface.

Abstract: The experiment on the friction and wear of the lithium grease is done by choosing the ZrO2 nanoparticles as the additive in order to study the change of the tribological property of the lithium grease. The friction coefficient decreases by over 30% if the ZrO2 nanoparticles with the mass fractions of 0.25% and 0.5% are used as the additive. The ZrO2 nanoparticles with the mass fraction of 0.25% and 0.5% reach the best result and the wear scar diameter can decrease by 48.8% and 46.5%, respectively.

Abstract: Dry sliding tests with electric current were carried out on a pin-on-disc system tribometer in this study, where copper-base powder metallurgy material and copper alloy QCr0.5 were used as the pin and the disc respectively. The researches were aimed at exploring relation between tribological properties and current stability of the couple under different loads. The results indicate that the current stability and friction coefficient increases with current and load. Moreover, co-effect between the current stability and tribological behavior has been found, which behaves in the way that the higher the current stability, the higher dynamic current collection capability and tribological properties.

Abstract: Recent researches have found that surfaces with non-glazed or laser dimpling topography offer improved lubricating efficiency and wear resistance under lubrication conditions over their conventional glazed status. It was carried out in this paper to simulate a pin-on-disk experimental condition and perform hydrodynamic lubrication (HL) calculations for both non-glazed and glazed surfaces under conditions of different sliding velocities and loads with a view of understanding the tribological mechanism and characteristics of non-glazed surfaces. The results showed that the minimum film thickness of non-glazed surfaces, which closed to a typical elasto-hydrodynamic lubrication (EHL) film thickness, was thicker than that of glazed surfaces under the condition of low sliding velocities and small loads. At the same time, a decreased maximum pressure of full-film of non-glazed surfaces demonstrated an even pressure distribution on them.