Standstill Corrosion and Spall Propagation in Rolling Bearings

Abstract

Some surface-initiated related bearing failures have their source in standstill corrosion. This can be an important issue in transportation, energy, pulp and paper and other industries where bearings run long journeys generating relatively high temperatures or being in contact with humidity and then they stop overnight were they get cold, in this way producing condensation of humidity around the contacts. This condensation can generate pitting corrosion (depending on temperatures and environment). Pitting corrosion can be very mild and without consequences but sometimes it is the source of small cracks and spalls. When the bearing runs again, these surface defects will be triggered by rolling contact fatigue and can propagate, eventually producing a large spall and a bearing failure. The present paper investigates the interaction of the phenomenon of pitting corrosion with rolling contact fatigue and proposes an engineering concept model where the main parameters are investigated giving some indication of safe and unsafe combinations for spall propagation from standstill corrosion.