Graphite as Dry Lubricant to Reduce Rail Wheels Wear Level

Abstract

Wear occurs in rail wheels due to varying surface contact between wheel and railway. Many materials are used to minimize the wear effect of friction, one of which is graphite. Graphite has been known having dry lubricating ability. To find out the effect of graphite lubrication on wear level of wheel and railway, an experiment-based research is important to conduct. This research started with designing the construction of disc-on-disc wear testing instrument, wheel specimen using EMS45 material and railway specimen using VCL140 material. Dry lubricant used was graphite bar polished onto wheel specimen surface. The result of research showed that graphite could adhere to wheel surface and penetrate into the fissures of contact between wheel and railway. Varying graphite polishing conducted once in 5 minutes and 10 minutes resulted in different volume of graphite filling in the fissures of wheel specimen surface. The more the graphite volume polished onto wheel specimen surface, the less is the material loss due to surface contact. Graphite’s ability of filling in this contact area fissure when administered in appropriate volume would enable graphite to be a good dry lubricant. If this graphite polishing technique is applied to rail wheels, it would be beneficial, as it can lengthen the wheel life.

Rheological and tribological evaluation of friction modifiers for wheel‐rail applications

“…The typical solid lubricant is MoS 2 . Graphite has also been used, [8][9][10][11] but MoS 2 is currently the most commonly used. On the other hand, in this work, two commercial materials with MoS2 were evaluated.…”

Structure and Properties of Pseudo-Graphenes. Review

“…The described structure leads to anisotropy of properties in graphite for directions parallel or perpendicular to the atomic layers [8]. If we take one isolated atomic layer of graphite, then we get graphene -twodimensional atomic pattern with hexagonal carbon rings, in which sp 2 -hybridization is also realized [10]. Nanotubes [5,11] and fullerenes [4,12] also possess sp 2 hybridization.…”

“…graphite, which has a wide variety of usage (for example, as a dry lubricant [2] and an electric conductor [3]), fullerenes that can be used in creation of optical devices [4], carbon nanotubes [5], which, have promising applications in biomedicine [6], and graphene-material that can be used in electronics [7].…”

“…It is known that a carbon atom has 4 valence electrons. Interatomic bond "carbon-carbon" (C -C) can be sp 1 -, sp 2 -or even sp 3 -hybridized. For example, diamond has a face centered cubic crystal lattice, where all atoms are connected by sp 3 bonds.In this case, all four valence electrons participate in forming strong covalent bonds with neighboring atoms.…”

“…If we take one isolated atomic layer of graphite, then we get graphene -twodimensional atomic pattern with hexagonal carbon rings, in which sp 2 -hybridization is also realized [10]. Nanotubes [5,11] and fullerenes [4,12] also possess sp 2 hybridization. In addition, cases are possible when several types of bond hybridization are observed in a single carbon allotrope [13,14].…”