The influence of lubricant type on rolling contact fatigue of pearlitic rail steel

The minimisation of rail and wheel wear by the use of lubricants has recently progressed from the use of grease to the use of solid lubricants. A preliminary study into the implications of the change in lubrication method for rail rolling contact fatigue (RCF) was carried out. The tests were carried out on a twin-disc rolling-sliding contact simulation machine, using a maximum Hertzian contact pressure of 1500MPa with -1% slip. The results showed that depending on the lubrication method, fatigue life could vary by up to an order of magnitude, but that in all cases it was longer than that of a water lubricated contact. It was concluded that under the conditions examined, dry methods of solid lubricant application can offer an effective means of lubrication without the possibility of enhancing rail RCF. Solid lubricants dispersed in liquid media give superior friction and wear reduction, but under the conditions tested lead to RCF.