Influence of Car Tonnage and Wheel Adhesion on Rail and Wheel Wear: A Laboratory Study

1986 ◽  
Vol 108 (1) ◽  
pp. 48-58 ◽  
Author(s):  
S. Kumar ◽  
P. K. Krishnamoorthy ◽  
D. L. Prasanna Rao
Keyword(s):  
Wear Rate ◽  
Wheel Wear ◽  
Wheel Load ◽  
Adhesion Coefficient ◽  
Wear Rates ◽  
Bilinear Relation ◽  
Mild Wear ◽  
Rate Versus ◽  
Freight Car ◽  
Plastic Shakedown

This study presents the results and analysis of a laboratory investigation, of rail and wheel wear under clean and dry tangent track conditions, utilizing the IIT-GMEMD quarter scale simulation facility. Important factors influencing rail degradation are discussed followed by five different load/lubrication classifications of contacts. Influence of two important parameters, viz. wheel load (N) and adhesion coefficient of the tractive wheels (μ), on rail and wheel wear has been studied under conditions of Hertzian simulation. Seven separate experiments were conducted to measure wear of rail and nontractive freight car wheels. These were followed by six additional wear tests, simulating a typical U.S. locomotive, to investigate the effect of adhesion coefficients. The wear rates for tonnages* exceeding 65–70 t car increase at a much higher rate than those for tonnages below 65 t. Nonlinear relationship showing wear rate proportional to N5.4 and a bilinear relation have been developed. Considerations of contact plasticity show that the stress corresponding to 68-t freight load is a threshold stress which when exceeded leads to continual plasticity of new rails thus preventing shakedown. The influence of adhesion coefficient is also quite nonlinear, the wear rates being much higher for μ > 0.3. Photomicrographs of the surfaces of the wheel and rail at the end of the tests showed mild wear for μ ≤ 0.25 and severe wear for μ ≥ 0.35 indicating a transition of wear mechanism from mild to severe slightly above μ = 0.25. Wear rate is found to be approximately proportional to the square of the adhesion coefficient. A bilinear relation of wear rate versus μ, which is more accurate, is also given. It was observed that the effect of adhesion is more severe than the effect of tonnage alone. However, the tonnage effect is of serious consequence regarding plastic shakedown of the rails. A formulation of wear rate as a combined function of tonnage and adhesion coefficient is given. The urgent need for a solution of this problem is pointed out.

The dry wear of steels I. The general pattern of behaviour

1965 ◽  
Vol 257 (1077) ◽  
pp. 31-50 ◽  
Keyword(s):  
Wear Rate ◽  
General Framework ◽  
General Pattern ◽  
Sliding Speed ◽  
Wear Process ◽  
Wear Rates ◽  
Mild Wear ◽  
Wide Range ◽  
A Minor ◽  
Severe Type

The broad trends of the wear rate when steels rub together without lubrication have been studied by means of pin and ring apparatus. Over a wide range of load (10 g to 40 Kg) and sliding speed (1.7 to 266 cm/s) the wear process at equilibrium is either of a severe type, producing coarse metallic debris, or of a mild type, producing fine oxidized debris. The corresponding wear rates differ by more than two orders of magnitude. Transitions from one wear process to the other occur at well-defined loads and for soft steels a basic pattern, comprising three transitions, has been identified: T1 a change from mild wear to severe at light loads; T2, a change from severe wear back to mild at higher loads; T3, a minor change in the mild wear rate at loads above T2, characterized by divergent wear rates of the pin and ring. The way in which this pattern varies with the sliding speed and with the composition and hardness of the steel is traced and the findings of previous investigations co-ordinated in the general framework.

Strategies of maintenance and repair of agricultural machinery

2020 ◽  
pp. 38-48
Author(s):  
Aleksey S. Dorokhov ◽  
Aleksandr V. Denisov ◽  
Aleksey A. Solomashkin ◽  
Valeriy S. Gerasimov
Keyword(s):  
Wear Rate ◽  
Technical Condition ◽  
Research Purpose ◽  
Agricultural Machinery ◽  
Maintenance And Repair ◽  
Wear Rates ◽  
Urgent Task ◽  
Machine Parts ◽  
Current Value ◽  
Agricultural Machines

Modern machines are subject to progressive wear that occurs at different rates, which leads to unpredictable failures that reduce the reliability and durability of machines. The strategy of maintenance and repair is aimed at eliminating these problems. (Research purpose) The research purpose is in analyzing the basic principles of the strategy of maintenance and repair of agricultural machinery in order to ensure control of the technical condition of machine parts. (Materials and methods) When resource diagnostics is used, , the allowable value of the parameter is set in advance for a part . This value is the tolerance that corresponds to a certain wear rate of the part. The tolerance is set based on the condition that if the current value of the controlled resource parameter during the next diagnosis is less than the set value, then such a part at the current value of the wear rate can be finalized until the next inter-control check. Taking into account the wear rate of the same type of parts from the group when determining the allowable wear during their resource diagnostics becomes an urgent task. (Results and discussions) As a result of research, the article presents "Methodology for determining the main indicators of reliability of parts of agricultural machines with different wear rates" and "Methodology for determining the tolerance system of parts of agricultural machines with different wear rates". (Conclusions) The article presents the tolerance system that reduces the probability of failure of machine parts in operation. During resource diagnostics, those parts whose resource parameters exceed the tolerance are rejected.

scholarly journals Sliding Wear of Conventional and Suspension Sprayed Nanocomposite WC-Co Coatings: An Invited Review

2021 ◽  
Author(s):  
R. Ahmed ◽  
O. Ali ◽  
C. C. Berndt ◽  
A. Fardan
Keyword(s):  
Wear Rate ◽  
Thermal Spray ◽  
Sliding Wear ◽  
Failure Modes ◽  
Thermal Spray Coatings ◽  
Annual Growth Rate ◽  
Total Energy Consumption ◽  
Wear Performance ◽  
Wear Rates ◽  
Spray Coatings

AbstractThe global thermal spray coatings market was valued at USD 10.1 billion in 2019 and is expected to grow at a compound annual growth rate of 3.9% from 2020 to 2027. Carbide coatings form an essential segment of this market and provide cost-effective and environmental friendly tribological solutions for applications in aerospace, industrial gas turbine, automotive, printing, oil and gas, steel, and pulp and paper industries. Almost 23% of the world’s total energy consumption originates from tribological contacts. Thermal spray WC-Co coatings provide excellent wear resistance for industrial applications in sliding and rolling contacts. Some of these applications in abrasive, sliding and erosive conditions include sink rolls in zinc pots, conveyor screws, pump housings, impeller shafts, aircraft flap tracks, cam followers and expansion joints. These coatings are considered as a replacement of the hazardous chrome plating for tribological applications. The microstructure of thermal spray coatings is however complex, and the wear mechanisms and wear rates vary significantly when compared to cemented WC-Co carbides or vapour deposition WC coatings. This paper provides an expert review of the tribological considerations that dictate the sliding wear performance of thermal spray WC-Co coatings. Structure–property relationships and failure modes are discussed to grasp the design aspects of WC-Co coatings for tribological applications. Recent developments of suspension sprayed nanocomposite coatings are compared with conventional coatings in terms of performance and failure mechanisms. The dependency of coating microstructure, binder material, carbide size, fracture toughness, post-treatment and hardness on sliding wear performance and test methodology is discussed. Semiempirical mathematical models of wear rate related to the influence of tribological test conditions and coating characteristics are analysed for sliding contacts. Finally, advances for numerical modelling of sliding wear rate are discussed.

Determination of Steady-State Adhesive Wear Rate

2005 ◽  
Author(s):  
L. J. Yang
Keyword(s):  
Steady State ◽  
Wear Rate ◽  
Wear Test ◽  
Standard Test ◽  
Test Method ◽  
Testing Time ◽  
Wear Coefficient ◽  
Wear Rates ◽  
Test Methodology

Wear rates obtained from different investigators could vary significantly due to lack of a standard test method. A test methodology is therefore proposed in this paper to enable the steady-state wear rate to be determined more accurately, consistently, and efficiently. The wear test will be divided into four stages: (i) to conduct the transient wear test; (ii) to predict the steady-state wear coefficient with the required sliding distance based on the transient wear data by using Yang’s second wear coefficient equation; (iii) to conduct confirmation runs to obtain the measured steady-state wear coefficient value; and (iv) to convert the steady-state wear coefficient value into a steady-state wear rate. The proposed methodology is supported by wear data obtained previously on aluminium based matrix composite materials. It is capable of giving more accurate steady-state wear coefficient and wear rate values, as well as saving a lot of testing time and labour, by reducing the number of trial runs required to achieve the steady-state wear condition.

scholarly journals Reduction of freight car wheel wear of 1520 mm gauge railways

2020 ◽  
Vol 985 ◽  
pp. 012004
Author(s):  
V Ushkalov ◽  
T Mokriy ◽  
I Malysheva ◽  
L Lapina ◽  
S Pasichnik ◽  
...  
Keyword(s):  
Wheel Wear ◽  
Freight Car

TRIBOLOGICAL PROPERTIES OF THE CARBON AND NITROGEN-BASED HARD FILMS SLIDING AGAINST THE NICKEL-BASED SUPERALLOY

2020 ◽  
Vol 27 (08) ◽  
pp. 1950197
Author(s):  
X. L. LEI ◽  
B. X. YANG ◽  
Y. HE ◽  
F. H. SUN
Keyword(s):  
Tribological Properties ◽  
Cutting Tools ◽  
High Hardness ◽  
Wear Rates ◽  
Nickel Based Superalloy ◽  
Dlc Coating ◽  
Nano Crystalline ◽  
Debris Particles ◽  
Mild Wear ◽  
Super Alloy

This study is focused on the tribological properties of micro- and nano-crystalline diamond (MCD and NCD), non-hydrogenated and hydrogenated diamond-like carbon (DLC and DLC-H) and nitrogen-based (CrN, TiN and TiAlN) coatings sliding against the super alloy Inconel 718, in terms of the maximal and average coefficients of frictions (COFs), the worn morphologies and the specific wear rates, by the rotating ball-on-plate configuration under dry condition. The results show that the nitrogen-based films show comparable COFs and wear rates with the WC–Co substrates. The DLC and DLC-H show lower COFs compared with the nitrogen-based films. Furthermore, their wear resistance is limited due to their low thickness compared with MCD and NCD, which have the same elemental composition. The DLC-H coating exhibits much lower wear rate compared with the DLC coating, which may be derived from the passivation of dangling bonds by the linking of H to C atoms. The MCD and NCD films show the lowest average COFs and mild wear after tribotests, due to their high hardness and low adhesive strength between pure diamond and the super alloy. Among all the tested films, the NCD film-based tribopair presents the lowest maximal and average COFs, tiny wear debris particles, mild wear of ball and plate without scratching grooves, indicating that the NCD film may be suitable to be deposited on cutting tools for super alloy machining.

Wear and osteolysis outcomes for highly cross-linked polyethylene in primary total hip arthroplasty compared with conventional polyethylene: a 15- to 18-year single-centre follow-up study

2020 ◽  
pp. 112070001989697 ◽  
Author(s):  
Nam Hoon Moon ◽  
Won Chul Shin ◽  
Min Uk Do ◽  
Suk-Woong Kang ◽  
Sang-Min Lee ◽  
...  
Keyword(s):  
Wear Rate ◽  
Survival Rates ◽  
Reoperation Rate ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Total Hip ◽  
Kaplan Meier ◽  
Long Term Result ◽  
Wear Reduction

Background: Although highly positive results for wear reduction of highly cross-linked polyethylene (HXLPE) have been reported around the 10-year follow-up, the long-term result related to reoperation and wear-related survival is still an issue. Therefore, this study aimed to compare the follow-up results of a single manufacture’s polyethylene liner for >15 years in terms of survival and wear rate. Methods: This retrospective cohort study included 134 primary total hip arthroplasties (THAs) who were followed up for at least 15 years. The mean age at the time of surgery was 50.7 years (conventional polyethylene [CPE] group = 22; HXLPE group = 112). Linear and volumetric wear rates of polyethylene were measured, and the reoperation rate and radiographic osteolysis were evaluated and Kaplan-Meier survival analysis was performed in both groups. Implant-related complications were also examined. Results: HXLPE group showed a significantly lower wear rate in both linear and volumetric wear. None of the hip radiographs showed evidence of loosening or osteolysis in the HXLPE group. The survival rates at 15- to 18-year follow-up were 90.9% and 95.5% in the CPE and HXLPE groups when all-cause reoperation was the endpoint, and 90.9% and 100.0% when the wear-related reoperation was the endpoint, respectively. Implant-related complications were not different between the 2 groups. Conclusions: Wear reduction and osteolysis showed a great advantage in HXLPE after a 15-year follow-up. Although the CPE and HXLPE showed excellent survival, wear and osteolysis were more frequent in the CPE; therefore, the high risk of reoperation in the future should be considered.

A Simulation Study on the Effects of Race Surface Waviness on Cage Dynamics in High-Speed Ball Bearings

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Linkai Niu
Keyword(s):  
Wear Rate ◽  
Dynamic Model ◽  
High Speed ◽  
Wave Amplitude ◽  
Ball Bearing ◽  
Ball Bearings ◽  
Cage Effect ◽  
Surface Waviness ◽  
Slip Ratio ◽  
Wear Rates

The effects of the race surface waviness on the cage dynamics, including cage slip ratios, cage instabilities, and time-averaged cage wear rates, in high-speed ball bearings are investigated. A dynamic model of high-speed ball bearings considering the cage effect and the race surface waviness is proposed. Based on the proposed dynamic model, the effects of the maximum wave amplitude (MWA) and the wave order (WO) of race surface waviness on cage slip ratio, cage instability, and time-averaged cage wear rate are investigated. The results show that the race surface waviness has a great effect on the cage dynamics. The waviness would increase the random impacts between balls and cage pockets and thus cause more instable motion of the cage. Although the ball skidding and the cage slip ratio decrease with the increase of MWA, the cage instability and the cage wear rate become severe when MWA increases. In addition, the effect of WO on cage dynamics is nonlinear. The current investigation could provide a theoretical tool for an in-depth understanding of the dynamics in a high-speed ball bearing.

Evaluation of Wear Rate of Nanocrystalline Diamond Films Using Abbott Curve

2017 ◽  
Vol 267 ◽  
pp. 185-189
Author(s):  
Andrei Bogatov ◽  
Vitali Podgursky
Keyword(s):  
Wear Rate ◽  
Cross Sections ◽  
Vapour Deposition ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapour ◽  
Nanocrystalline Diamond ◽  
Wear Rates ◽  
Nanocrystalline Diamond Films ◽  
Worn Surface

The nanocrystalline diamond films were deposited by microwave plasma enhanced chemical vapour deposition (PE-CVD) on Si (100) substrate. Reciprocating sliding tests were conducted using Si3N4 balls as a counter body. A method based on the construction of the Abbott curve representing the areas of pristine and worn surface in the wear scars was applied for estimation of the wear rate. The calculated wear rates were compared with the results obtained by profilometric measurements and direct measurement of the wear scars cross sections by scanning electron microscopy (SEM).

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