Contamination & Abrasive Wear
Solid particles or corrosive ingress scoring the rolling contact surfaces.
Symptoms
Fine scoring, scratching or dulling of the raceways and rolling elements. Ingress of grit, dust or moisture produces abrasive wear patterns and, where moisture is present, rust staining and pitting.
Likely causes
Foreign particles entering the bearing through damaged seals, dirty lubricant, poor installation hygiene, or operation in a contaminated environment. Moisture ingress causes corrosion that accelerates surface breakdown.
Prevention
Use effective sealing appropriate to the environment. Keep lubricant clean and sealed. Maintain clean mounting practices. Relubricate to flush out contaminants. Consider sealed/shielded bearings for dirty environments.