An electron backscatter diffraction investigation on microstructural evolution of pearlite wheel steel near rolling contact fatigue crack tip

2021 ◽  
Author(s):  
Chun‐Peng Liu ◽  
Guan‐Zhen Zhang ◽  
Peng‐Tao Liu ◽  
Chun‐Huan Chen ◽  
Rui‐Ming Ren
Keyword(s):  
Fatigue Crack ◽  
Microstructural Evolution ◽  
Electron Backscatter Diffraction ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Crack Tip ◽  
Rolling Contact ◽  
Wheel Steel ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Relationships between the fatigue crack growth resistance characteristics of a steel and the tread surface damage of railway wheel

2018 ◽  
Vol 2 (90) ◽  
pp. 49-55 ◽  
Author(s):  
O.P. Ostash ◽  
V.V. Kulyk ◽  
T.M. Lenkovskiy ◽  
Z.A. Duriagina ◽  
V.V. Vira ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Crack Growth Resistance ◽  
Rolling Contact ◽  
Wheel Steel ◽  
Fatigue Crack Growth Resistance ◽  
Railway Wheels

Purpose: The aim of the proposed research is to establish experimentally the relation between damaging of the tread surface of model wheels and the characteristics of fatigue crack growth resistance of wheel steels "KI th, "KII th, "KI fc, "KII fc), depending on its microstructure. Design/methodology/approach: Characteristics of the fatigue crack growth resistance have been determined on the specimens cut out from the hot rolled plate of thickness 10 mm of the steel which is an analogue of railway wheel steels. To obtain different steel microstructures and its strength level, test specimens were quenched (820°C, in oil) and then tempered at 400°C, 500°C, and 600°C for 2 h. The characteristics of Mode I fatigue crack growth resistance of steel were determined on the basis of fatigue macrocrack growth rate diagrams da/dN–"KI, obtained by the standard method on compact specimens with the thickness of 10 mm at a frequency of 10-15 Hz and the stress ratio R = 0.1 of the loading cycle. The characteristics of Mode II fatigue crack growth resistance were determined on the basis of da/dN–"KII diagrams, obtained by authors method on edge notched specimens with the thickness 3.2 mm at a frequency of 10-15 Hz and R = –1 taking account of the crack face friction. The hardness was measured with a TK-2 hardness meter. Zeiss-EVO40XVP scanning electron microscope was used for microstructural investigations. Rolling contact fatigue testing was carried out on the model specimens of a wheel of thickness 8 mm and diameter 40 mm in contact with a rail of length 220 mm, width 8 mm and height 16 mm. Wheels were manufactured form the above-described steel after different treatment modes. Rails were cut out from a head the full-scale rail of hardness 46 HRC. The damaging was assessed by a ratio of the area with gaps formed by pitting and spalling to the general area of the wheel tread surface using a special stand. Findings: The growth of the damage of the tread surface of the model wheels correlates uniquely with the decrease of the cyclic fracture toughness of the wheel steel "KI fc and "KII fc, determined at Mode I and Mode II fracture mechanisms. These characteristics of the wheel steel can be considered as the determining parameter of this process, in contrast to the fatigue thresholds "KI th and "KII th. Research limitations/implications: Investigations were conducted on model wheels that simulate the damage of real railway wheels tread surface. Practical implications: A relationship between the damage of tread surface of railway wheels and the strength level of wheel steels is determined. Originality/value: The damage of the tread surface of the model wheels during the rolling contact fatigue of the pair wheel-rail increases with the growth of the strength (hardness) of the wheel steel, which corresponds to the statistical data of the operation of the real railway wheels.

A Predictive Rolling Contact Fatigue Crack Growth Model: Onset of Branching, Direction, and Growth—Role of Dry and Lubricated Conditions on Crack Patterns

2002 ◽  
Vol 124 (4) ◽  
pp. 680-688 ◽  
Author(s):  
M. C. Dubourg ◽  
V. Lamacq
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Interfacial Crack ◽  
Rolling Contact ◽  
Propagation Behavior ◽  
Branch Formation ◽  
Complex Crack ◽  
Crack Growth Model

Complex crack networks are initiated in rails under Rolling Contact Fatigue. This paper attempts to model the RCF crack propagation with a particular emphasis on the branching conditions and the parameters that play a role on them. The numerical tool proposed rests on the combination of the author’s RCF model, Hourlier and Pineau’s criterion for the branch prediction and experimental data and the corresponding models for fatigue crack extension that are derived from a Joint European project. Parametric studies on the influence of (i) residual stresses, (ii) both interfacial crack and wheel/rail contact frictional effects, (iii) neighboring crack are conducted to reach a better understanding of the RC crack propagation behavior and more particularly the branch conditions, i.e., the length of the primary crack prior to branch formation and the branch direction.

Analysis and characterization by electron backscatter diffraction of microstructural evolution in the adiabatic shear bands in Fe–Cr–Ni alloys

2009 ◽  
Vol 24 (8) ◽  
pp. 2617-2627 ◽  
Author(s):  
Huajie Yang ◽  
Yongbo Xu ◽  
Yasuaki Seki ◽  
Vitali F. Nesterenko ◽  
Marc André Meyers
Keyword(s):  
Microstructural Evolution ◽  
Electron Backscatter Diffraction ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Adiabatic Shear Bands ◽  
Localized Deformation ◽  
Ni Alloys ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Equiaxed Grains

The microstructural evolution inside adiabatic shear bands in Fe–Cr–Ni alloys dynamically deformed (strain rates > 104 s−1) by the collapse of an explosively driven, thick-walled cylinder under prescribed strain conditions was examined by electron backscatter diffraction. The observed structure within the bands consisted of both equiaxed and elongated grains with a size of ∼200 nm. These fine microstructures can be attributed to recrystallization; it is proposed that the elongated grains may be developed simultaneously with localized deformation (dynamic recrystallization), and the equiaxed grains may be formed subsequently to deformation (static recrystallization). These recrystallized structures can be explained by a rotational recrystallization mechanism.

Effect of Lubricant on Surface Rolling Contact Fatigue Cracks

2010 ◽  
Vol 97-101 ◽  
pp. 793-796 ◽  
Author(s):  
Khalil Farhangdoost ◽  
Mohammad Kavoosi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Cracks ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Hertzian Contact ◽  
Element Analysis ◽  
Crack Face ◽  
Hertzian Contact Stress ◽  
Model Of Friction

This study performed the finite element analysis of the cycle of stress intensity factors at the surface initiated rolling contact fatigue crack tip under Hertzian contact stress including an accurate model of friction between the faces of the crack and the effect of fluid inside the crack. A two-dimensional model of a rolling contact fatigue crack has been developed with FRANC-2D software. The model includes the effect of Coulomb friction between the faces of the crack. The fluid in the crack was assumed not only to lubricate the crack faces and reduce the crack face friction coefficient but also to generate a pressure.

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.

Investigation on rolling contact fatigue of railway wheel steel with surface defect

Wear ◽  
2020 ◽  
Vol 446-447 ◽  
pp. 203207 ◽  
Author(s):  
Dongfang Zeng ◽  
Tian Xu ◽  
Weidong Liu ◽  
Liantao Lu ◽  
Jiwang Zhang ◽  
...  
Keyword(s):  
Surface Defect ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wheel Steel ◽  
Railway Wheel ◽  
Railway Wheel Steel
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