Dry and lubricated wear of rail steel under rolling contact fatigue - Wear mechanisms and crack growth

Wear ◽  
2017 ◽  
Vol 380-381 ◽  
pp. 240-250 ◽  
Author(s):  
Santiago Maya-Johnson ◽  
Juan Felipe Santa ◽  
Alejandro Toro
Keyword(s):  
Crack Growth ◽  
Wear Mechanisms ◽  
Rail Steel ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Fatigue Wear

Equilibrium of crack growth and wear rates during unlubricated rolling-sliding contact of pearlitic rail steel

2000 ◽  
Vol 214 (2) ◽  
pp. 93-105 ◽  
Author(s):  
D. I. Fletcher ◽  
J. H. Beynon
Keyword(s):  
Steady State ◽  
Crack Growth ◽  
Rail Steel ◽  
Fatigue Cracks ◽  
Rolling Contact Fatigue ◽  
Crack Depth ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Sliding Contact ◽  
Test Machine

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.

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

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.

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

2016 ◽  
Vol 846 ◽  
pp. 577-582
Author(s):  
Asitha C. Athukorala ◽  
Dennis V. de Pellegrin ◽  
Ben T. Battaglia ◽  
Kyriakos I. Kourousis
Keyword(s):  
Rail Steel ◽  
Ion Beam ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Wear Particle ◽  
Rolling Contact ◽  
Particle Analysis ◽  
Wear Particles ◽  
Fatigue Wear ◽  
Deformed Layer

Particle analysis methodology is presented, together with the morphology of the wear debris formed during rolling contact fatigue. Wear particles are characterised by their surface topography and in terms of wear mechanism. Rail-wheel materials are subjected to severe plastic deformation as the contact loading progresses, which contributes to a mechanism of major damage in head-hardened rail steel. Most of the current methodologies involve sectioning of the rail-wheel discs to trace material damage phenomena such as crack propagation and plastic strain accumulation. This paper proposes methodology to analyse the development of the plastically deformed layer by sectioning wear particles using the focussed ion beam (FIB) milling method. Moreover, it highlights the processes of oxidation and rail surface delamination during unlubricated rolling contact fatigue.

scholarly journals Effect of Gas Nitriding on Interface Adhesion and Surface Damage of CL60 Railway Wheels under Rolling Contact Conditions

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 911
Author(s):  
Qiang Wu ◽  
Tao Qin ◽  
Mingxue Shen ◽  
Kangjie Rong ◽  
Guangyao Xiong ◽  
...  
Keyword(s):  
Wear Behavior ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wheel Surface ◽  
Fatigue Wear ◽  
Material Loss ◽  
Surface Protection ◽  
Gas Nitriding ◽  
Railway Wheels

The influence of surface gas nitriding on wheel/rail rolling contact fatigue and wear behavior of CL60 wheel was studied on a new rolling contact fatigue/wear tester (JD-DRCF/M). The failure mechanisms of the wheel/rail surface after the gas nitriding and without gas nitriding on the wheel surface were compared and analyzed. The results show that the wheel with gas nitriding could form a dense and hard white bright layer which was approximately 25 μm thick and a diffusion layer which was approximately 70 μm thick on the wheel surface. Thus, the gas nitriding on the railway wheel not only significantly improved the wear resistance on the surface of the wheel, but also effectively reduced the wear of the rail; the results show that the material loss reduced by 58.05% and 10.77%, respectively. After the wheel surface was subjected to gas nitriding, the adhesive coefficient between the wheel/rail was reduced by 11.7% in dry conditions, and was reduced by 18.4% in water media, but even so, the wheel with gas nitriding still could keep a satisfactory adhesive coefficient between the wheel/rail systems, which can prevent the occurrence of phenomena such as wheel-slip. In short, the gas nitriding on the wheel surface can effectively reduce the wear, and improve the rolling contact fatigue resistance of the wheel/rail system. This study enlarges the application field of gas nitriding and provides a new method for the surface protection of railway wheels in heavy-duty transportation.

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