Development of white etching layers on rails: simulations and experiments

Bernsteiner, Christof; Müller, Gabor; Meierhofer, Alexander; Six, Klaus; Künstner, David; Dietmaier, Peter

doi:10.1016/j.wear.2016.03.028

Cited by 46 publications

(16 citation statements)

References 13 publications

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“…The temperature function inFig. 7corresponds to the thermal distribution proposed by Bernsteiner et al[28], who found an increase of temperature in the trailing edge of the wheel-rail contact patch.Besides, they showed that temperatures around the austenitization level are possible. That means at least 700 C° is attained for the R260Mn grade.…”

supporting

confidence: 71%

“…Austenitization occurs over a depth with a temperature in the range between the austenitization temperature T AC1 and T max . The martensitic transformation takes place when the temperature decreases fast enough below the martensitic start transformation temperature (T ms ), which is 200 C° for the R260 grade [28]. When the cooling rate is not fast enough or slowed down for some reason, other phases may be formed according to the Time-Temperature-Transformation (TTT) diagram for the specific steel grade.…”

mentioning

confidence: 99%

“…The frictional heat in the surface provokes a pearlite-austenite transformation where the temperature exceeds 700 C°, downward into the rail. Bernsteiner et al assumed that the material over the entire austenized depth transforms into martensite; they validated their assumption using a full-scale simulator with new R260 rail and reproduced an accurate thickness of the white etching layer[28].…”

mentioning

confidence: 99%

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Stratified surface layers on rails

Messaadi

Steenbergen

2018

Wear

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This study examines the properties of stratified surface layers on rails in service and presents a hypothesis explaining their origin. The stratified layer consists of a white etching top layer and a brown sublayer. The metallurgical composition and properties of this sublayer are found to match with that of globular bainite. The occurrence of stratification in the surface layer is explained by the thermomechanical cycle for a material point on the rail surface under wheel-rail contact. Difference in the surface and subsurface cooling rates after reaching the austenitisation temperature may lead, depending on the chemical steel composition, to the generation of two different phases (martensite and bainite) and stratification. The exclusive occurrence of sandwich layers on rails that have been in service is attributed to the hardening of the top layer, leading to a reduced thermal conductivity, which gains relevance at an increasing depth. The granular morphology of the bainitic sublayer, exhibiting weak globular inclusions, facilitates the initiation and the propagation of transverse cracks, thus contributing to the development of RCF.

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confidence: 71%

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confidence: 99%

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Stratified surface layers on rails

Messaadi

Steenbergen

2018

Wear

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“…Interestingly though, this surface layer is not evident in all cases [6], as the deformed layer can wear off before reaching the critical state. Researchers [7] have attempted to study and produce numerical models to reflect this phenomenon, which can significantly reduce the life span of the rail material. Twin-disc testing will generate a considerable thermal effect due to the repetitive and adherent nature of the disc surfaces, which would help recreate any thermal effects occurring under more severe railway operating conditions.…”

Section: Resultsmentioning

confidence: 99%

Wear Particle Analysis and the Evolution of the Plastically Deformed Layer on Australian Rail Steel

Athukorala

Pellegrin

Battaglia

et al. 2016

AMM

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“…The shape of the characteristic changes with rails surface conditions that complicate the nonlinearity description. The factors that influence the characteristic are, e.g., in [12]. The dependence is nonlinear and can cause failure of some slip controllers.…”

Section: B Estimatorsmentioning

confidence: 99%

Implementations of UKF and EKF for Wheel Slip Control Purpose to Locomotive Computer

Pichlík

2018

2018 International Conference on Applied Electronics (AE)

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Modern electric locomotives have to transfer high tractive effort between wheels and rails. Therefore, they have to be equipped with slip controllers that enable to achieve required force and keep wheelsets velocity in the acceptable value. The slip controller is a part of the locomotive control algorithm that runs on an axle computer that is typically a digital signal processor with limited computational power. The modern slip controller requires determining an actual value of adhesion that cannot be directly measured during the train runs. Therefore, the adhesion estimation is necessary. Extended Kalman filter or unscented Kalman filter can be used with an advantage because they can cope with some drawbacks of conventional methods. However, they are not typically used because of their high computational requirements. Therefore, the extended Kalman filter and unscented Kalman filter are implemented into a digital signal processor that is typically used in the locomotives as an axle computer to verify the possibility of used slip control methods based on the mentioned estimators in the paper. The verification is made on measured data. Keywords-slip control; extended Kalman filter;unscented Kalman filter; railway.Where φD-W is a difference angle in the different ends of the shaft, ωM is the motor angular velocity, ωW is the wheel angular velocity, i is estimated adhesion, cMW and dMW is a stiffness and damming of the shaft between the motor and the wheel, JM and JW are moments of inertia of the motor and wheel respectively and rG is a gear ratio of the gearbox.

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Development of white etching layers on rails: simulations and experiments

Cited by 46 publications

References 13 publications

Stratified surface layers on rails

Stratified surface layers on rails

Wear Particle Analysis and the Evolution of the Plastically Deformed Layer on Australian Rail Steel

Implementations of UKF and EKF for Wheel Slip Control Purpose to Locomotive Computer

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