Tribological performance and self-lubricating mechanism of the laser-textured surface filled with solid lubricant in rolling friction pair

2018 ◽  
Vol 70 (2) ◽  
pp. 371-384 ◽  
Author(s):  
Xijun Hua ◽  
Xuan Xie ◽  
Bifeng Yin ◽  
Peiyun Zhang ◽  
Jinghu Ji ◽  
...  

Purpose 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. Design/methodology/approach 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. Findings 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. Originality/value The results of the experimental studies demonstrated the application prospect of laser surfaces texturing combined with solid lubricant in rolling friction pair.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jinlong Shen ◽  
Tong Zhang ◽  
Jimin Xu ◽  
Xiaojun LIU ◽  
Kun Liu

Purpose This paper aims to improve the tribological performance of grease-lubricated spherical plain bearings (SPBs) under heavy load, dimple-type textures were prepared by laser on the outer surface of the inner ring. The influence of roughness parameters of a textured surface on reducing friction coefficient and temperature rise was also explored. Design/methodology/approach This study adopts a laser processing method to fabricate dimple-type textures. Three-dimensional roughness parameters were used to characterize the textured surfaces. The friction coefficients of five SPBs with surface texture and one original commercially available SPB without surface texture under different nominal loads were measured on a self-established test rig. The data of temperature rise were obtained by nine embedded thermal couples. Findings The results indicate that SPBs with textures generally exhibit lower friction coefficients than the original SPB without textures. The dimple depth has a significant influence on improving the tribological performance, which coincides with the analysis by surface roughness parameters. A textured surface with negative Ssk and high Vvc has the minimum temperature rise. Originality/value As it is too difficult to arrange sensors into heavy-load SPBs, there are few reports about the temperature characteristics. Through nine embedded thermal couples, the distribution of temperature rise on the inner ring of SPBs was given in this study. The positive effect of surface texture on reducing temperature rise and friction coefficient was verified, which is beneficial for the design of heavy-load SPBs.


2019 ◽  
Vol 72 (3) ◽  
pp. 427-431
Author(s):  
Ke Li ◽  
Xiuping Dong ◽  
Mingji Huang ◽  
Ping Chen

Purpose This paper aims to improve the wear resistance of metal rubber microfilaments and the service life. The effect of surface texture by laser processing on the fretting friction properties of metal rubber microfilaments was studied. Design/methodology/approach The LQL-F20A laser marking machine was used to fabricate a ring groove array with equal spacing and dense arrangement on the surface of metal rubber microfilaments. The test was carried out with a self-made micro-dynamic frictional tester. The topography of the microfilaments was observed by scanning electron microscopy and analyzed. Findings It has shown that laser surface texturing can improve the wear performance of microfilaments. Under the same experimental conditions, the microfilaments of textured surface has a smaller depth of wear than un-textured specimen. The wear resistance increases with the increase of texture density. The friction coefficient of textured specimen is significantly reduced compared with un-textured specimen, and the surface texture density of microfilaments has little influence on the friction coefficient after stabilization. In the stage of stable fretting wear, the wear depth will be more with the increase of the load. Originality/value There is little research on metal rubber microfilaments tribological properties. In this paper, the effect of laser texturing of microfilaments on micro-dynamic friction properties was studied by friction machine to provide a reference for the application of metal rubber in aerospace, medical and other fields.


2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Xijun Hua ◽  
Julius Caesar Puoza ◽  
Jianguo Sun ◽  
Peiyun Zhang ◽  
Jinghu Ji ◽  
...  

Experimental studies of friction and wear on textured surfaces filled with composite solid lubricant and lubricated with grease were conducted on a sliding plain bearing to enhance the working performance and lifetime under different conditions. Circular microdimples of different diameters were fabricated on GCr15 bearing steel specimens using the semiconductor sound and light pumped Nd:YAG laser machining equipment. Ring-on-ring tribological test configuration with GCr15 tribopairs under a combined non-Newtonian lubrication of grease and composite lubricant was performed. The results showed that the surface textures on specimen GCr15 bearing steel material filled composite solid lubricant and lubricated with grease (TLG), reduced the friction by 27%, 46%, and 75% of the grease only (TG), solid lubricant only (TL), and nonlubricated (T) specimens, respectively. The textured specimen with dimple diameter of 109 μm lowered the maximum coefficient of friction by 38% and enhanced the antiwear properties of GCr15 bearing steel material remarkably. This indicated that grease has great potential in promoting service life and working performance of sliding plain bearing when combined with composite solid lubricant in a laser-textured surface. It is therefore beneficial for applications in the machinery and automotive components industries in saving energy and reducing CO2 emission.


2013 ◽  
Vol 404 ◽  
pp. 106-111
Author(s):  
Kang Mei Li ◽  
Zhen Qiang Yao ◽  
Yong Xiang Hu

Surface texturing has been recognized as an effective means to improve the tribological performances of sliding surfaces. Different densities of micro dimples were fabricated on Oxygen-Free High Conductivity (OFHC) copper by laser peen texturing (LPT). The tribological characteristics of the samples were tested by surface-to-surface sliding contact experiments under constant sliding velocity and linearly increased normal load. The effects of texture density on the friction coefficient, failure time and load carrying capacity were investigated. It was found that in comparison with smooth surfaces, textured surfaces help to reduce the friction coefficient, prolong the failure time and improve the load carrying capacity. Results also suggested that there might exit an optimum texture density with which the surface exhibits better tribological behavior than those with higher and lower texture densities.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ting Wang ◽  
Hanfei Guo ◽  
Jianjun Qiao ◽  
Xiaoxue Liu ◽  
Zhixin Fan

PurposeTo address the lack of data in this field and determine the relationship between the coefficient of friction and the interference between locomotive wheels and axles, this study evaluates the theoretical relationship between the coefficient of friction and the interference under elastic deformation.Design/methodology/approachWhen using numerical analyses to study the mechanical state of the contacting components of the wheels and axle, the interference between the axle parts and the coefficient of friction between the axle parts are two important influencing factors. Currently, as the range of the coefficient of friction between the wheel and axle in interference remains unknown, it is generally considered that the coefficient of friction is only related to the materials of the friction pair; the relationship between the interference and the coefficient of friction is often neglected.FindingsA total of 520 press-fitting experiments were conducted for 130 sets of wheels and axles of the HXD2 locomotive with 4 types of interferences, in order to obtain the relationship between the coefficient of friction between the locomotive wheel and axle and the amount of interference. These results are expected to serve as a reference for selecting the coefficient of friction when designing axle structures with the rolling stock, research on the press-fitting process and evaluations of the fatigue life.Originality/valueThe study provides a basis for the selection of friction coefficient and interference amount in the design of locomotive wheels and axles.


2020 ◽  
Vol 72 (6) ◽  
pp. 805-810
Author(s):  
Hua Zhang ◽  
Guangwu Zhou ◽  
Ping Zhong ◽  
Kepeng Wu ◽  
Xingwu Ding

Purpose The purpose of this paper is to study the influence of friction coefficient of materials with different elastic modulus on the variation of velocity and load under water lubrication and oil lubrication conditions. Design/methodology/approach Low-viscosity lubricating oil and water were used as lubricants to test the friction performance of the ball-disc contact friction pair in the lubrication state on the universal micro-tribometer multi-functional friction and wear test system. Findings In the same speed range, the lubrication states from soft to rigid materials are not necessarily similar to each other. Generally, the material with low elastic modulus is suitable in low-viscosity lubricant environments, while the material with high elastic modulus has relatively smaller friction coefficients in oil-lubricated environments compared with water lubrication. However, the coefficients of polyethylene, polytetrafluoroethylen and polyoxymethylene are exceeded by rubber’s coefficients under water lubrication in the same experiment environments, and their lubrication states are not affected by lubricants. The friction coefficient of the friction pair decreases with the increase of loads; however, it does not apply to all materials. The friction coefficients of materials with smaller elastic modulus such as rubber under high loads are rather large. Therefore, the elastic modulus of the material under high loads is a factor to be considered. Originality/value The Stribeck curves study of the ball-disk contact friction pair comprising soft and rigid materials, whose elastic modulus is from hundreds of GPa to a few of MPa, was carried out. The influence of different speeds, loads and lubricants on the friction coefficient of the friction pair was revealed, which provided a research basis for the selection and matching of friction pair materials.


2017 ◽  
Vol 749 ◽  
pp. 241-245 ◽  
Author(s):  
Hatsuhiko Usami ◽  
Toshiki Sato ◽  
Yasuyuki Kanda ◽  
Satoru Nishio

Tribological properties of textured surfaces fabricated using a discontinuous microcutting process were investigated. Aluminum cast alloy (AC8A) discs were used for the specimens. The texturing process was carried out using a CNC machining center with a cutting edge with a novel geometry. The resulting surface morphology consisted of micro dimples with a diameter of 200-300 μm and a depth of 5-10 μm, with controlled area fractions of 10 and 40% and a top region finished with a milling cut. The tribological properties were evaluated using a ring-on-disc type testing apparatus under lubricated conditions, and showed that the friction coefficient of the textured surfaces was low and stable from the beginning of the experiment. A dependence of the friction coefficient on the area fraction was also found. Further reductions in the friction coefficient were achieved on a textured surface with a polished top region. It can be concluded that the proposed discontinuous micro cutting process is an effective means of fabricating a micro texture for the reduction and stabilization of frictional resistance.


2018 ◽  
Vol 12 (4) ◽  
pp. 603-610 ◽  
Author(s):  
Yue Sun ◽  
Keita Shimada ◽  
Shaolin Xu ◽  
Masayoshi Mizutani ◽  
Tsunemoto Kuriyagawa ◽  
...  

Experimental investigations were carried out to verify if the friction reduction in lubrication can be expanded by a textured surface with sawtooth riblets. Sawtooth riblets were formed by ultraprecision diamond cutting, with a ridge angle of about 60°–90° and height of about 20–50 μm on the contact surface. Six types of textured surfaces with different ridge angles, heights, and sliding directions were tested and compared with the untextured surface. The tribological tests were conducted by a flat-on-flat tribometer in lubrication. The effects of the ridge angle, height, and relative sliding direction on the friction coefficient in lubrication were reported.


2012 ◽  
Vol 184-185 ◽  
pp. 33-36
Author(s):  
Hua Qi Liang ◽  
Hui Fang Kong ◽  
Gen Fu Yuan

An object’s fine surface can change the object's surface friction property. So this paper aims to study the friction property of concave laser-textured surface through experiment. First, the Nd:YAG laser is used to generate micro-pores on Cr12 steel surface in the research and then its impact on object's surface friction property is studied. The test result shows that compared with the non-textured surfaces, the concave surface with area density of 5% and depth of I10.8 can reduce the friction coefficient significantly.


2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Xijun Hua ◽  
Jianguo Sun ◽  
Peiyun Zhang ◽  
Kai Liu ◽  
Rong Wang ◽  
...  

A combination technology of the solid lubricant and the laser surface texturing (LST) can significantly improve the tribological properties of friction pairs. The plate sample was textured by fiber laser and composite lubricant of polyimide (PI) and molybdenum disulfide (MoS2) powders were filled in the microdimples. Sliding friction performances of micron-sized composite lubricant and nano-sized composite lubricant were investigated by ring-plate tribometer at temperatures ranging from room temperature (RT) to 400 °C. On the one hand, the results of the micron-sized composite lubricant show that the friction coefficient of the textured surface filled with composite lubricant (TS) exhibits the lowest level and the highest stability compared to a textured surface without solid lubrication, smooth surface without lubrication, smooth surface burnished with a layer of composite solid lubricant. The better dimple density range is 35–46%. The friction coefficients of the sample surface filled with micron-composite solid lubricant with the texture density of 35% are maintained at a low level (about 0.1) at temperatures ranging from RT to 300 °C. On the other hand, the results of the nano-sized composite lubricant show that these friction properties are better than those of MoS2-PI micron-sized composite. The friction coefficients of MoS2-PI-CNTs nano-sized composite solid lubricant are lower than those of the MoS2-PI composite lubricant at temperatures ranging from RT to 400 °C. In addition, the possible mechanisms involving the synergetic effect of the surface texture and the solid lubricant are discussed in the present work.


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