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Article
Publication date: 28 January 2025

Xiao Xu, Yimin Zhang and Risheng Long

This paper aims to analyze the frictional performance of the phosphated CTRBs under dry sliding conditions. Through friction and wear experiments and characterization analysis…

3

Abstract

Purpose

This paper aims to analyze the frictional performance of the phosphated CTRBs under dry sliding conditions. Through friction and wear experiments and characterization analysis, this paper investigated the wear mechanism and anti-wear mechanism of the composite phosphating coatings.

Design/methodology/approach

This paper used a method of incorporating graphite particles and polytetrafluoroethylene (PTFE) particles into manganese-based phosphating solution to prepare composite phosphating coatings applied on cylindrical thrust roller bearings (CTRBs).

Findings

The results are as follows: the inclusion of functionalized graphite particles affects the characterization of the composite phosphating coatings, whereas PTFE particles serve a physical filling role and have no influence on the surface features of the composite phosphating coatings. The surface roughness of the composite phosphating coatings is the main factor affecting the frictional behavior of phosphated CRTBs. Roughness affects the amount of PTFE particles adsorbed on the surface of the phosphate crystals. PTFE particles can form a solid lubricating film at the friction interface, and under the same surface roughness conditions, phosphated CTRBs with added PTFE particles can improve its friction performance.

Originality/value

The characterization parameters of the composite phosphating coatings were controlled by adding functionalized graphite particles to the phosphating solution. The effects of adding only graphite particles and adding both graphite particles and PTFE particles on the surface characteristics of the phosphating coatings were discussed separately. The tribological performance of phosphating CTRBs was analyzed through friction and wear testing, and the influence of surface characteristics on wear mechanisms and anti-wear mechanisms was discussed.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2024-0405/

Details

Industrial Lubrication and Tribology, vol. 77 no. 3
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 18 July 2022

Risheng Long, Qiang Ma, Zhihao Jin, Yimin Zhang, Hui Han, Shaoni Sun and Xuanying Du

The purpose of this paper is to report the tribological behavior of dimples textured rolling element bearings (REBs) under variable load and starved lubrication.

141

Abstract

Purpose

The purpose of this paper is to report the tribological behavior of dimples textured rolling element bearings (REBs) under variable load and starved lubrication.

Design/methodology/approach

The pattern parameters include line-diameter of dimples (200 µm, 250 µm, 300 µm), depth of dimples (10 µm, 20 µm, 30 µm). Dimple patterns were prepared on the raceways of the shaft washers of cylindrical roller thrust bearings (CRTBs). A vertical wear test rig was used to obtain their coefficients of friction (COFs) under stepped load (1200–6000 N, with a manually increase of 1200 N every 3600 s) and starved lubrication. The wear losses and worn surfaces were characterized. The tribological performance between stepped load and fixed load (4000 N) was compared. The influence mechanism of dimples on the friction and wear properties of CRTBs under stepped load and starved lubrication was also discussed.

Findings

Compared with the data of smooth ones, the average COFs of the dimples textured bearings are almost all reduced under stepped load and starved lubrication, while their mass losses almost all get higher. The depth−diameter ratio and the effective volume coefficient of dimples are the important factors. In this work, compared with the smooth group, when the line-diameter of dimple is 250 µm and the depth is 20 µm, i.e. the depth−diameter ratio is 0.08, its average COF is reduced by 46.8% and its mass loss is reduced by about 7%, showing wonderful friction-reducing effect and good wear resistance.

Originality/value

This work can provide a reference for the raceway design of REBs.

Details

Industrial Lubrication and Tribology, vol. 74 no. 7
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 25 February 2022

Risheng Long, Qingyu Shang, Zhihao Jin, Yimin Zhang, Zichen Ju and Manhong Li

The purpose of this paper is to reveal the influence of dimples on the tribological properties of the “washers-cage-rollers” system of rolling element bearing (REB) under starved…

290

Abstract

Purpose

The purpose of this paper is to reveal the influence of dimples on the tribological properties of the “washers-cage-rollers” system of rolling element bearing (REB) under starved lubrication.

Design/methodology/approach

A fiber laser marking system was used to prepare dimples patterns on the raceways of the shaft washers of cylindrical roller thrust bearings (CRTBs). The friction and wear properties of dimples textured CRTBs with different diameter of dimples (200 µm, 250 µm, 300 µm) and depth of dimples (4 µm, 8 µm, 12 µm) were researched through a vertical universal wear test rig using a customized tribo-pair under starved lubrication. The surface stresses and the influence mechanism of dimple units on the tribological behavior of REBs were also compared and discussed.

Findings

Although the surface stresses on the raceways of dimples textured bearings are significantly higher than that of the smooth group, the coefficients of friction and wear losses of them are all reduced under starved lubrication. When the effective volume of dimples is between 1.13 and 2.25 and the depth of dimples is smaller than 12 µm, the tribological properties of dimples textured CRTBs are significantly improved. In this work, when the diameter of dimples is 250 µm, and the depth of dimples is 8 µm, the textured bearings can provide the excellent friction-reduction ability and outstanding wear resistance.

Originality/value

This work is a valuable reference for the raceway design and optimization of REBs.

Details

Industrial Lubrication and Tribology, vol. 74 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 14 March 2023

Yueyong Wang, Yimin Zhang and Risheng Long

This study aims to investigate the effect of compound pit textures on the tribological properties of thrust cylindrical roller bearings (TCRBs) using several parameters, such as…

177

Abstract

Purpose

This study aims to investigate the effect of compound pit textures on the tribological properties of thrust cylindrical roller bearings (TCRBs) using several parameters, such as compound type, pit diameter, pit depth and pit area density.

Design/methodology/approach

The surface texture parameters of the shaft washer (WS) raceway include pit diameter (D; 100, 300 and 500 µm), pit depth (H; 10 and 20 µm) and pit area density (S; 10%, 13% and 18%). Pits were produced on the WS of the TCRBs using laser marking equipment. The friction and wear performances of compound pit-textured TCRBs under starved lubrication conditions are studied using a friction and wear test rig. The influence mechanisms of the compound pit texture on the friction and wear properties of TCRBs are discussed through real tests and discussions.

Findings

Compared with nontextured bearings, the average coefficient of friction (ACOFs) and wear loss of TCRBs with single/compound pit textures are reduced when rotating under starved lubrication. D has the greatest effect on the COFs curve. When D = 300 µm, H = 10 µm and S = 10%, the ACOF and wear loss are the lowest, that is, 0.0207 and 3.38 mg, respectively. Under the same lubrication conditions, compared with the nontextured bearing group, the COF and wear loss are reduced by 41.4 and 59.6%, respectively.

Originality/value

This study provides a useful reference for the raceways of textured TCRBs.

Details

Industrial Lubrication and Tribology, vol. 75 no. 3
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 27 February 2025

Yazhe Chen, Qingyu Shang, Youwei Zhang, Ying Yao, Adesh Kumar Tomar, Risheng Long and Max Marian

This study aims to investigate the mechanical and tribological behavior of 70Mn steel with different laser re-melted textured patterns.

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Abstract

Purpose

This study aims to investigate the mechanical and tribological behavior of 70Mn steel with different laser re-melted textured patterns.

Design/methodology/approach

Laser surface re-melting (LSR) was used to manufacture various textured patterns (i.e. line, grid and mixed) on both the original and heat-treated 70Mn steel plates. The micro-hardness, microstructure, tensile strength, yield strength, elongation, coefficients of friction (COF) and worn morphologies were characterized to evaluate the impact of different textured patterns on the overall performance.

Findings

The results show that re-melted unit exhibited the highest surface hardness on the subsurface. The increase in surface hardness of the re-melted unit for the heat-treated 70Mn steel samples was much lower than that of the original ones. The re-melted textured patterns did not improve the tensile strength, yield strength and elongation of either original or heat-treated 70Mn steel samples. The re-melted textured patterns effectively reduced the average COFs of heat-treated 70Mn steel samples, but increased friction of the non-heat-treated samples.

Originality/value

This study provides valuable insights into enhancing the mechanical properties and tribological characteristics of 70Mn steel, particularly in the automotive, heavy machinery and high-load application sectors. These industries have stringent requirements for durability and friction control, and the findings of this research are expected to effectively extend the lifespan of mechanical components.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2024-0443/

Details

Industrial Lubrication and Tribology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 14 August 2021

Risheng Long, Chao Zhao, Zhihao Jin, Yimin Zhang, Zhen Pan, Shaoni Sun and Weihua Gao

The purpose of this paper is to reveal the friction and wear performance of grooves textured cylindrical roller thrust bearings with different groove dimensions under starved…

213

Abstract

Purpose

The purpose of this paper is to reveal the friction and wear performance of grooves textured cylindrical roller thrust bearings with different groove dimensions under starved lubrication.

Design/methodology/approach

The groove dimensions include: width of grooves (WOG, 50 µm, 100 µm and 150 µm), depth of grooves (DPOG, 7 µm, 11 µm and 15 µm) as well as groove deflection angle (GDA, 45°). A fiber laser marking system was used to prepare groove patterns on the raceways of shaft washers. The friction and wear properties of grooves textured bearings were researched through a vertical universal wear test rig using a customized roller bearing tribo-pair under starved lubrication. Static finite element analyses were conducted to reveal their surface stresses. Through the comprehensive comparison and analyses, the influence mechanism of grooves on the tribological behavior of cylindrical roller thrust bearings was proposed and discussed.

Findings

When grooves textured bearings run under starved lubrication, their average coefficients of friction (COFs) and wear losses are all significantly reduced and much lower than those of smooth group. The influence of DPOG on the COF curves is significant, while the influence of WOG on the COF curves is a little weak. The influence of groove dimensions on the surface stresses of grooves textured bearings is weak, whether the WOG or DPOG. In this work, when the WOG is 100 µm and the DPOG is 15 µm, its average COF and wear loss are both the lowest, 0.0066 and 0.61 mg, respectively. Compared with the data of smooth group, its friction coefficient is reduced by 75.3% and its mass loss is reduced by 95.8%, showing a significant improvement in this condition.

Originality/value

This work can provide a valuable reference for the raceway design and reliability optimization of rolling element bearings.

Details

Industrial Lubrication and Tribology, vol. 73 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Available. Content available
Book part
Publication date: 15 November 2018

Yi-Ming Wei and Hua Liao

Abstract

Details

Energy Economics
Type: Book
ISBN: 978-1-78756-780-1

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Article
Publication date: 14 November 2024

Bing Zhang, Cui Wang, Xuan Ze Ren and Bo Xia

The construction industry has been investigating “where Henry Ford is in the industry system.” Given that listed construction enterprises are the backbone of the promotion of the…

19

Abstract

Purpose

The construction industry has been investigating “where Henry Ford is in the industry system.” Given that listed construction enterprises are the backbone of the promotion of the high-quality development of the industry, their research and innovation are of considerable importance. This study aims to comprehensively assess the research and development (R&D) status quo and trends within various types of construction enterprises in order to identify effective strategies to enhance R&D efficiency in the construction industry.

Design/methodology/approach

Based on the data won from annual reports and the CSMAR database for the period 2016–2020, this study examines 104 listed construction enterprises in China. By applying both the data envelopment analysis (DEA) method and the Malmquist productivity index, this research compares and analyzes the static and dynamic differences in R&D efficiency across different types of construction enterprises.

Findings

Results suggest that the magnitude of change in the Malmquist decomposition index of 104 listed construction enterprises gradually narrowed, but the comprehensive technological level remained relatively low. Although state-owned enterprises had an advantage in scale efficiency, meaning they could maximize output with given inputs, their technological progress efficiency, also known as the degree of technological innovation, was significantly lower than that of private enterprises. As one finding, state-owned enterprises in comparison with private enterprises experience significant R&D inefficiency. It represents the main cause of their low degree of technological innovation and efficiency.

Originality/value

This study assesses the R&D efficiency of listed construction enterprises in China from the perspective of different market segments, state-owned and private enterprises and suggests approaches to improve strategies for various corporate types. Thus, the study’s new findings contribute to addressing the challenge of low R&D levels in the construction industry in the fields of engineering, construction and architectural management.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 15 June 2012

Hao Wei and Zhao Chunming

Considerable research has been conducted on the comparative advantage of Chinese manufactured exports before 2000, but too little attention has been focused on the twenty‐first…

4313

Abstract

Purpose

Considerable research has been conducted on the comparative advantage of Chinese manufactured exports before 2000, but too little attention has been focused on the twenty‐first century. With this rapid growth of China's export volume since 2001, what is the change in comparative advantage? Have qualitative changes taken place? The purpose of this paper is to conduct a thorough analysis of the comparative advantage of Chinese manufactures from 2002 to 2009, not only within the world market but also in the US market.

Design/methodology/approach

The research is based on 144 manufactures' comparative advantage in the US and world market, displaying the distribution and variation range for the comparative advantage of Chinese manufactures at different technological levels in the 2002‐2009 period with the RCA Index. This paper classifies 144 kinds of manufactures (on Standard International Trade Classification, Rev. 3 data) by technology level into five general groups and nine small groups, which cover the majority of Chinese manufactured exports.

Findings

First, the authors found that types of Chinese manufactured products with comparative advantage in both world and US markets are increasing. Most of the products with comparative advantage are low technology (LT) products. Second, in the world market, the comparative advantage of Chinese medium technology (MT) products has largely improved, but their RCA indexes are low and their kinds of products with very high comparative advantage are small. Third, as a whole, Chinese manufactured exports are of greater comparative advantage in the world market than in the US market. Specifically, LT products have the same position in world and US markets, while MT products and high technology (HT) products obviously have a greater comparative advantage in the world market.

Originality/value

First, little research has been conducted on the comparative advantage of Chinese manufactured exports since 2001. This paper undertakes a thorough analysis of the comparative advantage of Chinese manufactures from 2002 to 2009, not only within the world market but also in the US market. Second, it is very important for China to stabilize the overseas market demand and secure exports, this paper shows how China could cope with a crisis.

Details

Journal of Chinese Economic and Foreign Trade Studies, vol. 5 no. 2
Type: Research Article
ISSN: 1754-4408

Keywords

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