Rolling contact fatigue cracking in rails subjected to in‐service loading

Abstract

Rolling contact fatigue (RCF) is one of the most important failure mechanisms in rails with significant cost‐ and safety‐related implications on the operation of railway systems. In this work, a metallurgical analysis of RCF crack initiation and propagation, including geometrical characteristics of RCF cracks – length, depth from surface, angle of propagation and spacing between cracks, is presented. The role of proeutectoid ferrite in crack initiation has been studied. Analysis of the fracture surface of an RCF crack revealed a ductile initiation zone followed by a quasi‐cleavage crack propagation. Iron oxide formed in the interior of all cracks in rails exposed to stagnant water with implications to crack propagation rate because of crack closure effects. Sequential sectioning parallel to the rolling surface revealed that RCF cracks possess convoluted surfaces. The crack trace expands with depth from the rolling surface. Subsurface crack initiation has also been documented.

Shattered rim and shelling of high-speed railway wheels in the very-high-cycle fatigue regime under rolling contact loading

“…The severing mileage and crack initiation location for the shattered rim and shelling occurred in the CRH trains have been recorded. It is worth noted that few shattered rim and shelling were reported in the previous literatures [3][4][5][6]. The data of corresponding fatigue life and crack initiation location is not abundant which limits the systematic investigations.…”

“…Increased running speeds and axle loads are the main development direction in modern railway systems and continue to pose new challenge with respect to performance of key systems such as the wheel/rail pair [1,2]. Rolling contact fatigue (RCF) represents one of the main failure causes on wheel/rail pair and is attributed to the repeated contact between wheel and rail [3][4][5]. Three typical RCFs have been defined [6][7][8], i.e., surface initiated crack, subsurface crack initiation and interior initiated crack.…”

Experimental evaluation of the fatigue life of hydraulic gate cast iron rollers

“…Haidemenopoulos et al investigated RCF on three subway rail sections, approximately 1.5 m long over a 2‐year period of service. Based on operational data provided by the subway operator, it was estimated that over the 2‐year operation period, the rails had been subjected to 430 000 loading cycles (pass of a single wheel from a given rail location).The operational axle load (normal load) was determined to be 117.6 kN.…”

Enhancement of rolling contact fatigue performance of ferrite–pearlite steel with laser shock peening

“…In the past few years, extensive research works have been conducted to investigate the mechanism and influence factors of RCF of wheel and rail steels both experimentally and numerically. [13][14][15][16][17][18][19][20][21][22] Recently, a series of laser surface treatment technologies, such as laser melting, laser cladding, and laser dispersed treatment, have been applied for improving wear and RCF resistance of wheel and rail steels. [23][24][25] Those laser treatment techniques change the microstructure and stress status within laser-treated zone and inhibit the treated steel from delamination wear and delay the initiation of RCF crack.…”