A Laboratory Investigation of Threshold Stress in Wheel/Rail Interaction for Heavy Axle Loads

1992 ◽  
Vol 114 (1) ◽  
pp. 109-115 ◽  
Author(s):  
S. P. Singh ◽  
S. Kumar
Keyword(s):  
Carbon Steel ◽  
Wear Rate ◽  
Threshold Stress ◽  
Contact Stresses ◽  
Rolling Contact ◽  
Test Facility ◽  
Steel Rail ◽  
Wear Rates ◽  
Contact Wear ◽  
Axle Loads

This study is a continuation of earlier investigations to determine acceptable upper bound of contact stresses (threshold stress) for new wheel and rail under heavy axle load conditions. Using sharply increased wear rate (as initial maximum contact stress increases) under free rolling conditions as an indicator of threshold stress, laboratory investigations of wheel-rail rolling contact wear, simulating the 125-ton car wheel load, were conducted. Tangent track conditions with clean and dry surfaces were tested on two facilities; one of one-quarter scale and the other of one-fifteenth scale wheel-rail simulation. The earlier experiments conducted in the IIT Railroad Engineering Laboratory to investigate threshold stress used a varying load with the same wheel-rail profiles, the present study used constant load with varying wheel-rail profiles to determine whether the above increase in wear rate phenomenon will still be observed. While the results of the small (1/15th) scale facility were not considered quantitatively conclusive because of small size, qualitatively they indicated the presence of threshold stress phenomenon. The results of the one-quarter scale test facility very clearly confirmed that there is indeed a threshold stress above which the rolling contact wear rates increased sharply. The value of this stress, found to be approximately the same as reported in the earlier study, was nearly 200 ksi (for standard carbon steel rail). From the earlier and the present investigations of threshold stress, it is clearly concluded that the increased wear rates are primarily due to the increased initial contact stresses and 200 ksi is the value of threshold stress for standard carbon steel rail. Initial wheel-rail contact stresses for new wheel-rail should not be allowed to exceed this value to reduce damage to rail for heavy axle loads. It is recommended that new wheel-rail profiles should be developed to achieve stresses at or below this threshold stress level. Benefits of improved rail life with this approach are also discussed.

Threshold Stress Criterion in New Wheel/Rail Interaction for Limiting Rail Damage Under Heavy Axle Loads

1992 ◽  
Vol 114 (3) ◽  
pp. 284-288 ◽  
Author(s):  
S. Kumar ◽  
S. P. Singh
Keyword(s):  
Threshold Stress ◽  
Rolling Friction ◽  
Contact Stresses ◽  
Rolling Contact ◽  
Internal Damage ◽  
Stress Criterion ◽  
Plasticity Region ◽  
Proper Design ◽  
Axle Loads ◽  
Qualitative Discussion

This paper presents a qualitative discussion of the effects of increasing new (initial) wheel-rail contact stresses on the degree of damage to the rail due to heavy axle loads. The importance and need of heavy axle loads and its relationship to rail damage as a result of the increasing wheel-rail contact stresses is discussed. Various mechanisms of energy absorption/losses due to free rolling and modes of rail damage are presented. These modes include surface and internal damage due to wear, contact shear, plasticity, fatigue, shelling, crack formation, etc. The concept of threshold stress observed in free rolling friction much earlier by Drutowski is discussed and analyzed. It is believed by the authors that the threshold stress is s material property. This concept of threshold stress, based on sharply increased rates of wear in free rolling contact, is then presented and analyzed. Considerations of increased plasticity-region development, due to increasing contact stresses and their relationship to increased rates of wear seen in experiments, is utilized to determine an upper bound of contact stresses for new wheel and rail under heavy axle load conditions. It is indicated that new wheel-rail profiles, which will achieve contact stresses below the threshold stress, will enable the U.S. railroads to carry heavy axle loads without serious future damage to the rails. It is concluded that a satisfactory solution for maintaining rail integrity under heavy axle loads is possible with proper design accompanied with laboratory experimentation for the new steels as they may be used in the rails.

Enhancement of Rolling Contact Wear and Fatigue Resistance of Wheel Steel by Laser Dispersed Treatment

2014 ◽  
Vol 891-892 ◽  
pp. 1797-1802 ◽  
Author(s):  
Dong Fang Zeng ◽  
Lian Tao Lu
Keyword(s):  
Wear Rate ◽  
Fatigue Resistance ◽  
Rolling Contact Fatigue ◽  
Fatigue Crack Initiation ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wheel Steel ◽  
Premature Failure ◽  
Contact Wear ◽  
Delamination Wear

Ferrite-pearlite steel is the most widely used material for railway wheel. However, such wheel steel can not meet the strict demands for rolling contact wear and fatigue resistance with the rising speed and weight of traffic. The aim of this paper is to improve the rolling contact wear and fatigue resistance of wheel steel by laser dispersed treatment. Such treatment creates isolated glazed regions on the surface layer of wheel steel, which are composed of fine martensite and retained autensite and have an avera0ge hardness of 762HV0.3. Compared with the conventional laser surface treatment technologies, such as laser hardening, laser melting, or laser cladding, which have been applied for improving rolling contact wear and fatigue resistance of wheel/rail, the multiple overlapping laser tracks that cause the premature failure are avoided by laser dispersed treatment. The wear rate and rolling contact fatigue life of treated and untreated wheel steel were evaluated and compared by Amsler twin-disc testing machines in dry and lubricated condition, respectively. The test results show that laser dispersed treatment improves the rolling contact wear and fatigue resistance of wheel steel. The stable wear rate of the laser treated wheel steel is about 0.3 times that of untreated wheel disc and the average rolling contact life of treated wheel steel is about double that of the untreated steel. Further investigations show that the glazed regions suppress the plastic deformation of wheel steel. This inhibits the treated wheel steel from delamination wear and delays the formation of fatigue crack initiation.

Influence of Surface Treatment of High Carbon Steel on the Reciprocating Wear in Comparison With the 316 Stainless Steel

2009 ◽  
Author(s):  
U. D. Gulhane ◽  
Manish Roy ◽  
S. G. Sapate ◽  
S. B. Mishra ◽  
P. K. Mishra
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Wear Rate ◽  
High Carbon Steel ◽  
Composite Layer ◽  
High Carbon ◽  
Wear Rates ◽  
316 Stainless Steel ◽  
First Case ◽  
Reciprocating Wear

Diffusion treatments such as chromising and aluminising of high carbon steel results in the formation of Cr and Al rich layers on the surface. These layers will be responsible for formation of protective Cr2O3 and Al2O3 scale on exposure to corrosive environment. In view of extensive application of 316 Stainless Steel in biomedical engineering, present work is undertaken to examine the influence of diffusion treatment of high carbon steel on the reciprocating wear in Hank’s solution and to compare the same behavior with that of 316 SS. In order to achieve the above mentioned objectives, the wear rates of 316 SS, 304 SS, high carbon steel in aluminised and chromised condition have been evaluated. Though the general characteristics of the wear behavior, such as higher wear rate at higher load and at higher reciprocating speed, for all the materials are similar, aluminised and chromised high carbon steel exhibited best wear resistance especially at high and intermediate load. In simulated body fluid condition, 316 SS exhibited two different material removal mechanisms. In the first case, which is observed at higher load, material loss is by nucleation and propagation of crack. In the second mechanism which is prevalent at low and intermediate load, wear takes place by deterioration of composite layer formed on the surface by mixing the corrosion product and the substrate. Consequently it is noted that wear rate decreases with increase of hardness at higher load. At intermediate and at low load wear rate is less dependent of hardness.

scholarly journals Effects of Heat Treatment Condition and Counter Materials on the Wear Behavior of Laser Direct Energy Deposited Fe-8Cr-3V-2Mo-2W Alloy

2020 ◽  
Vol 58 (10) ◽  
pp. 680-692
Author(s):  
Kyeongsik Ha ◽  
Young Keun Park ◽  
Taehwan Kim ◽  
Gyeong Yun Baek ◽  
Jong Bae Jeon ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Wear Rate ◽  
Wear Behavior ◽  
High Carbon Steel ◽  
High Carbon ◽  
Wear Performance ◽  
Sliding Speed ◽  
Wear Rates ◽  
Direct Energy

This study aimed to investigate the wear performance of laser direct energy deposited Fe-8Cr3V-2Mo-2W alloy under various wear environments, in terms of different heat treatment conditions. Ball on disk tribology tests were performed using high-carbon steel and zirconia balls as counter materials. The wear rates of the alloy depended significantly on both the wear sliding speed and the wear load. Microstructural observations of the worn surface and the wear debris indicated intensive tribo-oxidative wear that was presumably responsible for the strong dependency of the wear rate on the wear sliding speed. Regardless of the type of counter materials, the alloy in the as-built state had better wear performance than the alloy with heat treatments. Therefore, the use of the alloy without post heat treatment would be favorable to obtain long-term durability of the alloy in severe wear environments. The wear tests with two different counter materials of high-carbon steel and zirconia showed the high-carbon steel counter material had a higher wear rate than the zirconia. This was thought to be due to that strong third-body abrasive actions of the high-carbon steel counter material, evidenced by the severe abrasive wear of the counter material.

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.

scholarly journals Rolling Wear of Silicon Nitride Bearing Materials

1990 ◽  
Author(s):  
John W. Lucek
Keyword(s):  
Fatigue Life ◽  
Silicon Nitride ◽  
Failure Modes ◽  
Fatigue Testing ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wear Performance ◽  
Wear Rates ◽  
Bearing Materials

Rolling-contact fatigue test methods were used to measure the wear performance of several silicon nitride materials. Sintered, hot pressed and hot isostatically pressed materials exhibited wear rates ranging over three orders of magnitude. Hot isostatically pressed materials had the lowest wear rates. Despite the disparity in wear performance, all materials tested had useful rolling-contact fatigue lives compared to steel. Fatigue life estimates, failure modes, and rolling wear performance for theses ceramics are compared to M-50 steel. This work highlights the rapid contact stress reductions that occur due to conformal wear in rolling-contact fatigue testing. Candidate bearing materials with unacceptably high wear rates may exhibit useful fatigue lives. Rolling contact bearing materials must possess useful wear and fatigue resistance. Proper performance screening of candidate bearing materials must describe the failure mode, wear rate, and the fatigue life. Guidelines for fatigue testing methods are proposed.

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 Influence of Induction Hardening on Wear Resistance in Case of Rolling Contact

2016 ◽  
Vol 66 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Michal Šofer ◽  
Rostislav Fajkoš ◽  
Radim Halama
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Induction Hardening ◽  
Rolling Contact ◽  
Isotropic Hardening ◽  
Wear Model ◽  
Wear Rates ◽  
C Programming Language ◽  
Hardening Rule ◽  
C Programming

AbstractThe main aim of the presented paper is to show how heat treatment, in our case the induction hardening, will affect the wear rates as well as the ratcheting evolution process beneath the contact surface in the field of line rolling contact. Used wear model is based on shear band cracking mechanism [1] and non-linear kinematic and isotropic hardening rule of Chaboche and Lemaitre. The entire numerical simulations have been realized in the C# programming language. Results from numerical simulations are subsequently compared with experimental data.

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.

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