Mechanical properties and fatigue behaviour of railway wheel steels as influenced by mechanical and thermal loadings

Nikas, Dimitrios; Ahlström, Johan; Malakizadi, Amir

doi:10.1016/j.wear.2016.04.009

Cited by 34 publications

(21 citation statements)

References 10 publications

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“…This is consistent with the strain concentration occurring at both extremities of the WEL spot (in the direction of axial force), which was shown clearly in the DIC results in Figure . The presence of softened pearlite microstructure around the WEL, as a result of the laser heating experiment and phase transformation could also influence the location of the crack initiation. Although the effect of the WEL as a stress concentration is important for the crack initiation, the influence of notches is known to be less significant during crack propagation .…”

Section: Discussionmentioning

confidence: 99%

Damage evolution around white etching layer during uniaxial loading

Jessop

Ahlström

Persson

et al. 2019

Fatigue Fract Eng Mat Struct

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Rolling contact fatigue cracks and thermally induced defects are common problems in the railway industry especially as demands for increasing loads, speeds, and safety continue to rise. Often, the two types of defects are found together in the field, however, whether one causes the other to occur is not completely agreed upon. The effect of thermal damage, in the form of a martensite spot on pearlitic steel test bars, on the fatigue life in uniaxial low cycle fatigue experiments was investigated by the authors. However, the focus of the current work was to characterize the damage evolution from the low cycle fatigue (LCF) tests and correlate the crack initiation and propagation with the initial thermal damage. Residual stress measurements, digital image correlation, and X‐ray tomography were used to characterize the effects of the thermal damage before, during, and after fatigue testing, respectively. It was found that the thermal damage causes strain accumulation and crack initiation at the interface between the two materials. The strain evolution was visualized using digital image correlation (DIC), clearly showing the strain concentrations at the top and bottom of the white etching layers (WEL), where the residual stresses are also most tensile. X‐ray tomography confirmed the planar crack growth from the martensite spot.

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Section: Discussionmentioning

confidence: 99%

Damage evolution around white etching layer during uniaxial loading

Jessop

Ahlström

Persson

et al. 2019

Fatigue Fract Eng Mat Struct

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“…The kinetics of spheroidisation are influenced by temperatures, accumulated exposure times, the extent of work hardening and alloying compositions. It is worth noting that severe plastic deformation at the wheel surface enhances spheroidisation by causing thinning and break-up of the lamellar carbide structure [4][5][6][7][8]. Simultaneously, spheroidisation allows more plastic deformation under the same level of wheel-rail loading.…”

Section: Microstructure Stabilitymentioning

confidence: 99%

“…The high-level plastic deformation on the wheel surface due to the combined effects of high contact stress and creepage conditions can accelerate this spheroidisation process by fracture and partial dissolution of cementite lamella in the pearlitic structure; this process is further enhanced by the increased dislocation density in the ferrite and ferrite/cementite interfaces during near-surface deformation due to accelerated carbon diffusion at dislocations [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

The role of microstructure and its stability in performance of wheels in heavy haul service

2017

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Thermal or thermo-mechanical loading is one of the major causes of wheel surface damage in Australian heavy haul operations. In addition, multi-wear wheels appear to be particularly sensitive to thermo-mechanical damage during their first service life. Such damage can incur heavy machining penalties or even premature scrapping of wheels. The combination of high contact stresses as well as substantial thermal loading (such as during prolonged periods of tread braking) can lead to severe plastic deformation, thermal fatigue and microstructural deterioration. For some high-strength wheel grades, the increased sensitivity to thermo-mechanical damage observed during the first service period may be attributed to the presence of a near-surface region in which the microstructure is more sensitive to these loading conditions than the underlying material. The standards applicable to wheels used in Australian heavy haul operations are based on the Association of American Railroads (AAR) specification M-107/M-208, which does not include any requirements for microstructure. The implementation of acceptance criteria for the microstructure, in particular that in the near-surface region of the wheel, may be necessary when new wheels are purchased. The stability of wheel microstructures during thermo-mechanical loading and the effects of alloying elements commonly used in wheel manufacturing are reviewed. A brief guide to improving thermal/mechanical stability of the microstructure is also provided.

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“…High‐speed railway wheels, including the wheel rim and web, are generally manufactured with ferrite‐pearlite steel . This steel is typically rolled, and the following heat treatment includes tempering and quenching .…”

Section: Introductionmentioning

confidence: 99%

“…High-speed railway wheels, including the wheel rim and web, are generally manufactured with ferrite-pearlite steel. 18 This steel is typically rolled, and the following heat treatment includes tempering and quenching. 19 The effect of FDBT on the fatigue crack propagation for high-speed railway wheel materials still remains unknown, and publications about the temperature sensitivity of the fatigue crack propagation of high-speed railway wheel materials are not available.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of temperature‐sensitive fatigue crack propagation of a high‐speed railway wheel rim material

Fang

Cai

Wang

et al. 2019

Fatigue Fract Eng Mat Struct

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The fatigue crack growth rate (FCGR) of ER8C high‐speed railway wheel rim material was tested at various service temperatures. The temperature sensitivity of fatigue crack propagation was evaluated, and the effect of temperature on the crack propagation mechanism was analyzed. The obtained results indicate a fatigue ductile‐to‐brittle transition (FDBT) point at −20°C for the ER8C wheel rim materials. A reverse relationship was found between FCGR and temperature for the near threshold and Paris regimes when the temperature was below the FDBT point. However, no evident changing rule was found when the temperature was above this transition point. An evident fatigue crack propagation mode transition was found from lamellar tearing to intergranular cracks, which was related to the FDBT for the near‐threshold regime.

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Mechanical properties and fatigue behaviour of railway wheel steels as influenced by mechanical and thermal loadings

Cited by 34 publications

References 10 publications

Damage evolution around white etching layer during uniaxial loading

Damage evolution around white etching layer during uniaxial loading

The role of microstructure and its stability in performance of wheels in heavy haul service

Evaluation of temperature‐sensitive fatigue crack propagation of a high‐speed railway wheel rim material

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