Molyneux-Berry, Paul, Davis, Claire and Bevan, Adam (2014) The influence of wheel/rail contact conditions on the microstructure and hardness of railway wheels. The Scientific World Journal, 2014 . pp. 1-16. doi:10.1155/2014/209752

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Abstract

The susceptibility of railway wheels to wear and rolling contact fatigue damage is influenced by the properties of the wheel material. These are influenced by the steel composition, wheel manufacturing process, and thermal and mechanical loading during operation. The in-service properties therefore vary with depth below the surface and with position across the wheel tread. This paper discusses the stress history at the wheel/rail contact (derived from dynamic simulations) and observed variations in hardness and microstructure. It is shown that the hardness of an “in-service” wheel rim varies significantly, with three distinct effects. The underlying hardness trend with depth can be related to microstructural changes during manufacturing (proeutectoid ferrite fraction and pearlite lamellae spacing). The near-surface layer exhibits plastic flow and microstructural shear, especially in regions which experience high tangential forces when curving, with consequentially higher hardness values. Between 1 mm and 7 mm depth, the wheel/rail contacts cause stresses exceeding the material yield stress, leading to work hardening, without a macroscopic change in microstructure. These changes in material properties through the depth of the wheel rim would tend to increase the likelihood of crack initiation on wheels toward the end of their life. This correlates with observations from several train fleets.

Item Type:	Journal Article
Subjects:	T Technology > TF Railroad engineering and operation
Divisions:	Faculty of Science > WMG (Formerly the Warwick Manufacturing Group)
Library of Congress Subject Headings (LCSH):	Railroad cars -- Wheels -- Testing, Steel in railroad engineering, Railroad rails
Journal or Publication Title:	The Scientific World Journal
Publisher:	Hindawi Publishing Corporation
ISSN:	1537-744X
Official Date:	16 January 2014
Dates:	Date Event 16 January 2014 Published 7 October 2013 Accepted 7 August 2014 Submitted
Volume:	2014
Page Range:	pp. 1-16
DOI:	10.1155/2014/209752
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Open Access
Funder:	Engineering and Physical Sciences Research Council (EPSRC), Rail Research UK Association, Great Britain. Rail Safety & Standards Board , Network Rail (Firm), Lucchini RS (Firm), Siemens-Aktiengesellschaft, Alsthom (Firm), Bombardier inc.

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