Designing steel composition and microstructure to better resist degradation during wheel - rail contact

Lead Research Organisation: University of Cambridge
Department Name: Materials Science & Metallurgy


To reduce whole-life costs of the railway system (through increased asset life, reduced maintenance) and generate performance improvements (such as increased service availability and reliability), it is important to select the optimum material composition for railway components. Selecting the optimum materials for wheels and rails is a complex task with many conflicting requirements, including: a range of failures mechanisms, variety of operating and loading conditions and the associated financial implications. This research will establish a comprehensive scientific understanding of the metallurgical characteristics of rail and wheel steels to enable scientifically-informed choices. It will take account of both the specific requirements arising from the peculiarities of railway wheel-rail contact and the economic trade-offs at a system-wide level.

Recent development of 'High Performance' (HPRail) rail steel by Tata Steel has shown that improvements in the resistance to both wear and rolling contact fatigue (RCF) can be achieved through judicious choice of alloying elements to alter the microstructural characteristic of the steel. However, the understanding of reasons for the success of such steels requires further fundamental research to establish how the different constituents of steel microstructures react to the forces imposed at the wheel-rail interface. The results of such research will help establish the design rules to engineer steel microstructures that provide a step change in the resistance to key degradation mechanisms with greater predictability of the deterioration rates.

The project combines the skills of an interdisciplinary team from four Universities (based at the Universities of Huddersfield, Cambridge, Leeds and Cranfield), necessary to deal with the complexity of the phenomena,
Description It is emphasised that work is not yet complete but significant results have been obtained and published. Rolling contact results in sub-surface stresses that are repeated on each occasion that a wheel traverses a rail surface. As a result damage accumulates, leading eventually to failure. We have published the mechanism of this failure in a carbide-free bainitic rail and demonstrated that it is totally different from that assumed conventionally for rails and bearings. The results have generic value since carbide-free bainitic steels have wider applications than rails.
Exploitation Route Both the publications and data are available on the web, and the work has stimulated a different line of thought in the context of bearing steels. That has been highlighted to bearing steel manufacturers, mainly via publications.
Sectors Education,Transport
Description Wilberth Solano, who is the post-doctor appointed on this project, was awarded a sum of 1000 GBP for his ability to communicate science ( Professor Bhadeshia presented the Larmor Lecture of the Cambridge Philosophical Society where some of the work from this project was included (
First Year Of Impact 2016
Sector Transport
Impact Types Societal