The influence of lubricant type on rolling contact fatigue of pearlitic rail steel

It is generally accepted that large rolling contact fatigue cracks in rails do not develop during unlubricated rolling-sliding contact, and damage under these conditions is restricted to wear of the rail steel. However, close examination of a worn rail steel surface reveals the presence of a multitude of wear flakes, the roots of which closely resemble shallow rolling contact fatigue cracks. Experiments have been conducted under unlubricated rolling-sliding conditions to examine the early development of flakes, or cracks, using a laboratory-based, twin-disc test machine to simulate the contact pressure and slip characteristic of the contact between a rail and a locomotive driving wheel. Small defects were found after as few as 125 unlubricated contact cycles. It was found that an equilibrium between crack growth rate and surface wear rate was established after approximately 10 000 cycles, leading to a shallow steady state crack depth. Initial crack growth by ratchetting (accumulation of unidirectional plastic strain until the critical failure strain of the material is reached), followed by shear stress-driven crack growth described by fracture mechanics, was found to be a sequence of mechanisms in qualitative agreement with the observed crack growth and steady state crack depth.

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Wear properties of two U71Mn K and U71Mn G rail steel welds during rolling contact fatigue

International Journal of Modern Physics B ◽

10.1142/s0217979219400411 ◽

2019 ◽

Vol 33 (01n03) ◽

pp. 1940041

Author(s):

Jinfang Peng ◽

Xuhui Xie ◽

Weijun Song ◽

Wei Li ◽

Zhiping Luo

Keyword(s):

High Speed ◽

Rail Steel ◽

Rolling Contact Fatigue ◽

Weld Zone ◽

Contact Fatigue ◽

Rolling Contact ◽

Superior Performance ◽

Wear Properties ◽

Abrasion Damage ◽

Steel Welds

Wear behaviors of two U71Mn K and U71Mn G rail steels have been systematically investigated with the simulated experiments during the tolling contact fatigue using samples taken from their base materials, the heat-affected zones near the weld, and the weld zones, respectively. The results demonstrate that there are significant differences between the nonweld and the weld zones for both steels. With higher hardness of U71Mn G over U71Mn K, the U71Mn G steel has mild abrasion damage, reduced weight loss from wear and reduced corrugations of the weld zone during the experiment with increased simulative speed; while its other features such as the plastic deformation and cracks are almost the same compared with the U71Mn K steel. The U71Mn G steel demonstrates superior performance over U71Mn K at the high-speed rolling experiment.

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Rolling Contact Fatigue and Wear Behavior of Rail Steel under Dry Rolling-Sliding Contact Condition

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.891-892.1545 ◽

2014 ◽

Vol 891-892 ◽

pp. 1545-1550

Author(s):

Jung Won Seo ◽

Hyun Kyu Jun ◽

Seok Jin Kwon ◽

Dong Hyeong Lee

Keyword(s):

Crack Growth ◽

Rail Steel ◽

Wear Behavior ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact ◽

Sliding Contact ◽

Maintenance Cost ◽

Rail Wear ◽

Railway System

Rolling contact fatigue and wear of rails are inevitable problems for railway system due to wheel and rail contact. Increased rail wear and increased fatigue damage such as shelling, head check, etc. require more frequent rail exchanges and more maintenance cost. The fatigue crack growth and wear forming on the contact surface are affected by a variety of parameters, such as vertical and traction load, friction coefficient on the surface. Also, wear and crack growth are not independent, but interact on each other. Surface cracks are removed by wear, which can be beneficial for rail, however too much wear shortens the life of rail. Therfore, it is important to understand contact fatigue and wear mechanism in rail steels according to a variety of parameters. In this study, we have investigated fatigue and wear characteriscs of rail steel using twin disc testing. Also the comparative wear behavior of KS60 and UIC 60 rail steel under dry rolling-sliding contact was performed.

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Decarburisation and rolling contact fatigue of a rail steel

Wear ◽

10.1016/j.wear.2005.03.005 ◽

2006 ◽

Vol 260 (4-5) ◽

pp. 523-537 ◽

Cited By ~ 36

Author(s):

R.I. Carroll ◽

J.H. Beynon

Keyword(s):

Rail Steel ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact

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Quantitative monitoring of brittle fatigue crack growth in railway steel using acoustic emission

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409717711292 ◽

2017 ◽

Vol 232 (4) ◽

pp. 1211-1224 ◽

Cited By ~ 6

Author(s):

Shengrun Shi ◽

Zhiyuan Han ◽

Zipeng Liu ◽

Patrick Vallely ◽

Slim Soua ◽

...

Keyword(s):

Acoustic Emission ◽

Condition Monitoring ◽

Structural Integrity ◽

Rail Steel ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact ◽

Night Time ◽

Structural Degradation ◽

Rail Infrastructure

Structural degradation of rails will unavoidably take place with time due to cyclic bending stresses, rolling contact fatigue, impact and environmental degradation. Rail infrastructure managers employ a variety of techniques and equipment to inspect rails. Still tens of rail failures are detected every year on all major rail networks. Inspection of the rail network is normally carried out at night time, when normal traffic has ceased. As the implementation of the 24-h railway moves forward to address the increasing demand for rail transport, conventional inspection processes will become more difficult to implement. Therefore, there is an obvious need to gradually replace outdated inspection methodologies with more efficient remote condition monitoring technology. The remote condition monitoring techniques employed should be able to detect and evaluate defects without causing any reduction in the optimum rail infrastructure availability. Acoustic emission is a passive remote condition monitoring technique which can be employed for the quantitative evaluation of the structural integrity of rails. Acoustic emission sensors can be easily installed on rails in order to monitor the structural degradation rate in real time. Therefore, apart from detecting defects, acoustic emission can be realistically applied to quantify damage. In this study, the authors investigated the performance of acoustic emission in detecting and quantifying damage in rail steel samples subjected to cyclic fatigue loads during experiments carried out under laboratory conditions. Herewith, the key results obtained are presented together with a detailed discussion of the approach employed in filtering noise sources during data acquisition and subsequent signal processing.

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