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The purpose of this paper is to describe the tribological characteristics with different area density of concave-convex micro-texture on the mold surface. It is a new technology to improve the quality of the workpiece to control the tribological properties through the application of concave-convex micro-texture on the mold surface.

Five groups of laser micro-texture with different area density (ratio of the concave-convex micro-texture area to the all-area) were processed on the surface of the mold steel, and the tribological properties were compared with the smooth surface of the reference sample.

The time of the running-in stage in different experimental groups was about 300 s. The fluctuation amplitude of concave-convex micro-texture friction coefficient is much larger than that of smooth plane specimen in the running-in stage. After the running-in stage, the friction coefficients were lower than that in the smooth condition and decreased with the increase of the concave-convex micro-texture area density. When the area density reached 25%, the friction coefficients no longer decreased significantly. In addition, the wear of concave-convex micro-texture surface is much lower than that of smooth surface and decreases with the increase of concave-convex micro-texture area density.

Domestic and foreign scholars have done a lot of research on the relationship between concave micro-texture and tribological properties. However, the object of this paper is a new concave-convex micro-texture, which is rarely studied in the field of tribology.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0081/

The purpose of this paper is to find the influence of surface bump texture combination characteristics on friction-wear properties so as to provide a basis for the selection of the bump texture combination scheme on the surface of the roll.

In this paper, six groups of different bump texture combination characteristics and their processing methods are introduced, of which three groups are regular distribution with different spacing and three groups are random distribution with different spacing. Then the effect of bump textures with different spacing, regular and random distribution on friction-wear properties was studied by ring block friction-wear experiments.

The results show that the friction coefficient of random distribution texture surface is lower than that of regular texture surface under the same spacing condition. In the regular distribution, the friction coefficient decreases with the increase of texture spacing. In the random distribution, the friction coefficient increases at first and then decreases with the increase of texture spacing. In addition, the wear resistance of textured surface is significantly higher than that of smooth surface because of the higher microhardness of the textured area. The attenuation ratio of textured surface roughness decreases with the increase of the distance between adjacent textures.

At present, the research on roller surface friction-wear is mainly based on the change of the overall surface roughness. However, there are few reports on the influence of the combination characteristics of laser bump texture on friction-wear from the microscopic scale.

This paper aims to find out the tribological performance and self-lubricating mechanism of the laser-textured surface filled with solid lubricant in rolling friction pair.

The textures on the surfaces of GCr15 bearing steel were produced by acousto-optic Q diode-pumped yttrium aluminum garnet laser with the technology of “single pulse one time, repeating at intervals” and filled with composite solid lubricant. The tribology tests were conducted on the MMW-1A universal friction and wear testing machine.

It was found that the solid-lubricated micro-textured surface can reduce the friction coefficient effectively. The MoS2/PI composite solid lubricant works better than the single MoS2 solid lubricant, and the ratio of PI/MoS2 + PI at 20 per cent is the best recipe. The friction coefficient of the sample surfaces decreases first and then increases with the increase in texture densities, and a texture density of 19.6 per cent has the best effect on friction reduction. The friction coefficient of the textured surfaces gradually decreases with the increase in both rational speed and load. For the same texture density, the friction coefficient of textured surfaces decreases slightly with the increase in diameter. Furthermore, the mechanism of “rolling-extrusion-accumulation” occurred on the textured surface can collect the solid lubricant, thereby, improve the effect of lubricating and anti-friction.

The results of the experimental studies demonstrated the application prospect of laser surfaces texturing combined with solid lubricant in rolling friction pair.

The purpose of this paper is to investigate a partially textured slider of infinite width with orientation ellipse dimples in liquid application.

In this paper, the pressure distribution of lubrication between a partially textured slider and a smooth sliding slider is calculated by the multi-grid method. For the same dimple area, the influence of the ellipse dimple with geometric parameters, and distribution and orientation on the hydrodynamic lubrication is evaluated in terms of the dimensionless average pressure for a given set of operating parameters.

In the present work, the magnitude of the dimensionless average pressure seems proportional to the slender ratio. Consequently, the slender ratio may be chosen as large as possible based on fabrication techniques. The longer axes of ellipse dimples placed parallel to the direction of sliding always show the better hydrodynamic effect. Furthermore, the results show that the ellipse dimples can greatly improve hydrodynamic effect of partially surface textured slider of infinite width by proper design of these texturing parameters.

This paper develops a partial surface texturing infinitely width slider with orientation ellipse dimples for improving hydrodynamic lubrication.