Sliding Wear of Rail and Wheel Steels: Effect of Hardness Ratio, Normal Load and Lubrication

Abstract

The pin-on-disc test model system was used to simulate contact wear between wheel flange and rail gauge corner. Pins were extracted from a class C cast steel wheel and discs were extracted from premium and intermediate steel grades rail, both hypereutectoid and with hardness between 321 and 392 HB. Rails are pearlitic and the bainitic wheel is in its first life. Dry and lubricated tests were performed with normal load variation (40, 80 and 120 N). Under dry condition, there was no influence of the pair hardness to mass loss of the tribosystem studied, contrary to what is stated by literature. For the lubricated tests, mass loss was significantly lower and regardless of both, hardness ratio and normal load, than in the other tests. This shows the technological importance of: (i) implementing wheel flange lubrication (locomotive embedded process); (ii) improving rail lubrication techniques (mobile or way side process) and/or friction coefficient measurement techniques and (iii) need for revision of wheel standards and/or specifications.

Brazilian Tribology: origin, status quo and future perspectives

“…A particular area of current concern is the correlation between laboratory experimental results and field-testing data. The ITV Tribology Group currently comprises five full-time researchers and about 15 Master, PhD and Postdoc students, as well as several academic visitors, working on a wide range of problems, including materials for rails [252,260,286,287,[452][453][454][455][456] and railway components [252,287,455], materials for iron ore grinding and crushing [300,445,457], conveyor belt components, lubrication [43,452,[458][459][460], contact mechanics, friction, wear, tribo-corrosion, surface fatigue and emerging technologies like robotics, advanced materials and green ship. This summary of the main activities in each group gives an extensive overview of the Brazilian tribology in different contexts.…”

Effect of rail cant on stress distribution

“…The literature shows that force increases the wear rate of the rail significantly. Viana et al (2020) showed that force increases in the order of 50% promote an increase in the wear rate of around 80%, according to the Archard model, in which the volumetric loss is proportional to the normal force. Thus, the 30% increase in lateral force for the 1/20 condition will promote accelerated rail wear compared to zero cant condition resulting in a longer rail life.…”

“…The contact at the flange root should be avoided, especially in a tangent, as it can speed up wheel wear, and increase the instability of the bogie (Shevstov, 2008). The contact of the wheel flange (either at the root or on the flange itself) with the gauge corner prevailing in creeping conditions and not of rolling conditions, which leads to an increase in the wear rate of both bodies (wheel and rail), because mechanisms of wear by creeping are more severe than rolling contact fatigue mechanisms (RCF) that occur in contact between the wheel bandage and the railhead (Lewis & Olofsson, 2009;Shevtsov, 2008;Viana et al, 2020).…”