An Experimental Study of Tribological Behavior of Journal Bearing Material under Powder and Granular Lubrication

Proper lubrication of mechanical components is very important for the reliable efficiency and useful life. The working temperature of the components can affect the lubricating oil and can degrade the lubricating characteristics of oil. This paper presents the experimental investigation on tribological behaviour of journal bearing material. Two types of additives are used in lubricating oili.e., powder and granular types of additives. The investigation is carried out on pin-on-disc apparatus to determine the wear and coefficient of friction. The statistical analysis is performed using design of experiments and Taguchi robust design to determine the optimum parameters of lubricating additives. It is found that for constant speed of 400 rpm with 5% concentration with varying size the granular lubrication have lower values than powder lubrication for all load conditions Keywords: Lubrication, pin-on-disc, Taguchi, additives.

Tribological properties of MoS2 powder-lubricated interface

Purpose This study aims to investigate the effect of MoS2 powder on tribological properties of sliding interfaces. Design/methodology/approach Loose MoS2 powder was introduced in the gap of point-contact friction pairs, and sliding friction test was conducted using a testing machine. Friction noise, wear mark appearance, microstructure and wear debris were characterized with a noise tester, white-light interferometer, scanning electron microscope and ferrograph, respectively. Numerical simulation was also performed to analyze the influence of MoS2 powder on tribological properties of the sliding interface. Findings MoS2 powder remarkably improved the lubrication performance of the sliding interface, whose friction coefficient and wear rate were reduced by one-fifth of the interface values without powder. The addition of MoS2 powder also reduced stress, plastic deformation and friction temperature in the wear mark. The sliding interface with MoS2 powder demonstrated lower friction noise and roughness compared with the interface without powder lubrication. The adherence of MoS2 powder onto the friction interface formed a friction film, which induced the wear mechanism of the sliding interface to change from serious cutting and adhesive wear to delamination and slight cutting wear under the action of normal and shear forces. Originality/value Tribological characteristics of the interface with MoS2 powder lubrication were clarified. This work provides a theoretical basis for solid-powder lubrication and reference for its application in engineering. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0150/

Experimental study on tribological characteristics in coke powder lubrication

Pushing coke is an important process in coke oven production. In the process of pushing coke, under the three-body contact state of steel, coke powder, and refractory brick, coke powder plays an important role in lubrication. In this article, a study on the macro- and micro-behavior and mechanism of coke powder lubrication is carried out through tribological tests. The results show that in the process of sliding friction, coke powder plays a role of lubrication through forming a powder layer and shearing occurred inside the powder layer. The load keeps at 5 MPa, under the lower velocity, the powder layer is thinner and delamination occurred in local position. While under the higher velocity, the coke powder can form a compact and complete powder layer and exhibit better lubrication characteristics. However, when the velocity increases to 0.52 m/s, the continuous powder layer is not formed, so the friction coefficient is higher, the frictional surface wears seriously and results in vibration to occur. The velocity keeps at 0.40 m/s, and the powder layer inclines to deteriorate under higher load. When the load increases to 20 MPa, a part of the powder layer is damaged, and severe wear occurs on the surface.