Abstract
Rolling contact fatigue can be enhanced by corrosion affecting the running surfaces in rolling bearings. Corrosion can trigger different phenomena affecting rolling contact fatigue performance. The present author has published a modelling methodology based on spall propagation from initial corrosion marks at the surface. The severity of the corrosion is assessed by whether the marks will produce a propagating spall at certain load. However, corrosion can weaken the overall steel strength to fatigue and in poor lubrication conditions surface-initiated fatigue can also develop at the bearing rolling surfaces, enhanced by the corrosion effects. In this paper the methodology presented earlier is improved by adding steel overall corrosion-weakening effects and the possibility to enhance surface-initiated fatigue and spall propagation from corrosion effects. In rolling bearings, some surface-initiated related bearing failures might have their source in standstill or pitting corrosion. Standstill corrosion can be an important issue in applications with constant starts and stops, like transportation, energy, pulp and paper and others where changes in temperature and moisture condensation is likely to happen. Pitting corrosion can also be produced by the continuous exposure of steel to corrosive environments, like some solvents, water and refrigerant chemicals. If the bearing runs again, surface damage can be triggered by rolling contact fatigue or surface-initiated fatigue and propagate, eventually producing a large spall and a bearing failure. The present paper explores both mechanisms surface-initiated fatigue and spall propagation as enhanced by overall corrosion effects in fatigue.
