Wear behaviour analysis of medium carbon high silicon alloy steel at different process parameter (original) (raw)
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Wear mechanisms and transitions in railway wheel steels
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2004
The need to improve safety and reduce costs means that new specifications are being imposed on railway wheel wear. These mean that more durable wheel steels are required. In order to develop such materials, a greater understanding is needed of the wear mechanisms and transitions occurring in wheel steels. In this work, twin-disc wear testing has been carried out to study the wear characteristics of R8T railway wheel steel. The results have indicated that, compared with previous wheel steels, R8T offers greater wear resistance. Three wear regimes were identified; mild, severe, and catastrophic. Wear rates were seen to increase steadily initially and then to level off, before increasing rapidly as the severity of the contact conditions increased. This paper is concerned with the form of the data and the reasons for the transitions. Analysis of the contact conditions indicated that the first transition in the wear rate was caused by the change from partial slip to full slip conditions ...
Wheel Material Wear Mechanisms and Transitions
In order to develop more durable wheel materials to cope with the new specifications being imposed on wheel wear, a greater understanding is needed of the wear mechanisms and transitions occurring in wheel steels, particularly at higher load and slip conditions. In this work wear assessment of wheel materials is discussed as well as wear rates, regimes and transitions. Twin disc wear testing, used extensively for studying wear of wheel and rail materials, has indicated that three wear regimes exist for wheel materials; mild, severe and catastrophic. These have been classified in terms of wear rate and features. Wear rates are seen to increase steadily initially, then level off, before increasingly rapidly as the severity of the contact conditions is increased. Analysis of the contact conditions in terms of friction and slip has indicated that the levelling off of the wear rate observed at the first wear transition is caused by the change from partial slip to full slip conditions at the disc interface. Temperature calculations for the contact showed that the large increase in wear rates seen at the second wear transition may result from a thermally induced reduction in yield strength and other material properties. Wear maps have been produced using the test results to study how individual contact parameters such as load and sliding speed influence wear rates and transitions. The maps are also correlated to expected wheel/rail contact conditions. This improved understanding of wheel wear mechanisms and transitions and will help in the aim of eventually attaining a wear modelling methodology reliant on material properties rather than wear constants derived from testing.
A pin-on-disk wear map of rail and wheel materials from different standards
A pin-on-disk wear map of rail and wheel materials from different standards, 2021
Wheel and rail materials are exposed to a large number of factors that affect their wear-resistant performance such as, large contact pressures, sliding speeds, high temperatures, material degradation by natural and artificial contaminants, etc. This directly affects the maintenance operations, so, an accurate wear prediction is required. Wear maps are an important tool to predict and identify wear regimes that impact maintenance schedules and consequently cost reduction. This work aimed to develop wear maps for a 115RE rail material and an ER8 wheel material, which are materials used in railways systems in Mexico, as well as identify the wear regimes and wear mechanisms replicating the wheel-rail interface conditions. Metallographic analysis and hardness tests were carried out for both materials. Wear tests were carried out by using a pin-on-disk tribometer. The resulting wear maps showed that a catastrophic wear regime occurs at medium sliding speed and low contact pressure values for the wheel. On the other hand, for rail, catastrophic wear regime occurs at high sliding speed and low contact pressure values.
Mapping railway wheel material wear mechanisms and transitions
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 2010
In order to develop more durable wheel materials to cope with the new specifications being imposed on wheel wear, a greater understanding of the wear mechanisms and transitions occurring in wheel steels is needed, particularly at higher load and slip conditions.
Wear, 2019
Wheel-rail contact is in the spotlight of Railway Engineering and its specific conditions are highly dependent on railroad characteristics, such as load, speed, track design and materials used, among others. To understand wear mechanisms for typical contact conditions of a railroad with many tight curves, sliding-wear tests were performed on pin-on-disc configuration, without lubrication, at various sliding speeds and constant normal load. The pins and discs were machined from rail and wheel materials, respectively. The worn volume of the samples were obtained by optical microscopy and 3D profilometry and the wear mechanisms were analyzed using a scanning electron microscope. The results indicate a higher friction coefficient for tests at a speed of 0.9 m/s, at about 0.8, when compared to the values obtained at 0.1 m/s-between 0.5 and 0.6. The wear severity of both pins and discs were up to four times higher in the tests carried out with a sliding speed of 0.1 m/s. Comparing the different materials of the discs, the wear of pins and discs were considerably greater in tribosystems with forged steel discs-about two to three times the wear. The wear mechanisms observed were predominantly of plastic nature, with occurrence of ploughing and adhesion of oxidized materials on the surface of pins and discs.
Wear, 2009
In the present work, the effect of carbon concentrations on the wear behavior of a Fe base alloy processed by powder metallurgy was investigated. Four Fe base alloys have been processed by mechanical alloying (MA). Mixtures of pure iron (mean particle size of 33 m) with different concentrations of carbon 0.84, 0.96, 1.16 and 1.40 wt.% (370 m)-0.3 wt.% Mn (33 m)-0.3 wt.% Si (5 m) were milled during 72 h using a horizontal ball mill in an argon atmosphere. 1 wt.% of zinc stearate was added as the process control agent. Powders were uniaxially cold-pressed at 400 MPa to obtain green compacts with 25 mm diameter and 9.7 mm height. The green compacts were sintered for 2 h at 1200 • C in vacuum and cooled to room temperature inside the furnace. For the wear tests, the samples were tested in dry and lubricated conditions. Pin-on-disc tribological tests according to ASTM G-99 standard were conducted under a normal load of 140 N and a constant tangential speed of 0.15 m/s in dry condition and lubricated condition with Chevron ultra duty grease TM. The worn surfaces were examined using scanning electron microscopy (SEM) to study the wear behavior of the steel. The wear rate and the wear coefficient k were measured. The results showed that the wear resistance and hardness of the samples increase by increasing the carbon content and it was found that the sample with 1.40 wt.% of carbon had the best wear resistance in lubricated condition with a dimensional wear coefficient of k = 2.1 × 10 −5 mm 3 m −1 N −1 .
Journal of Research and Development
In the present study, an experimental analysis of the friction forces, speeds and friction coefficients that influence the size of the wear track in a steel exposed to mechanical contact was carried out, for this, steel blocks with an alloying element of. 5% Cr base and D2 steel standard ring, representing the Block-on-Disk method, according to the ASTM D2714 standard were used. The test parameters were: 392N load, for 800 seconds, with variable speeds of 0.18 m/sec, 0.36 m/sec and 0.54 m/sec; the test is performed in a dry environment using the T-05 Block-on-Ring wear tester machine. This analysis contributes to the technological development of a material that has a lower coefficient of friction and therefore improves its mechanical properties for systems exposed to this principle, such as the wheels of traveling cranes or railway trains, diesel machinery transport systems and various services, etc.
EXPERIMENTAL INVESTIGATIONS OF SURFACE WEAR BY DRY SLIDING AND INDUCED DAMAGE OF MEDIUM CARBON STEEL
Diagnostyka, 2021
This study concerns the wear behaviour of metal couples used in industry, particularly in mechanical sliding systems (numerically controlled machine tools). In general, the nature of the materials of the parts of these systems which are in contact and move relatively, are medium carbon steels, thanks to their good mechanical and tribological properties. The present work aims to study, the dry sliding wear of the contact surface of the pin (machine slide) against the contact surface of a disc (machine groove) and the damage induced on the worn track. The pin is AISI 1038 and AISI 1045 steel, the disc is AISI 1055 steel. The tribological tests were carried out on a pin-disc tribometer, in an atmospheric environment. The wear of the pins being evaluated by weighing and studied according to the hardness of the pin with the variation of the normal load applied. The discussion of the results is based on SEM observations and EDS analyzes of worn surfaces and interfacial phenomena produced by dynamic contact. The results obtained indicated the influence of the applied load and the hardness on the wear of the pin and therefore on the tribological behaviour of the worn surfaces.