Corrosion damage to rolling bearings is generally due to corrosion (rust) caused by moisture: brown discoloration on the entire bearing surface, usually in the form of unevenly distributed small pits, Figure 53. In many cases, there are many rust spots distributed at the pitch of the rolling elements (static corrosion). When the bearing is stationary for a long time, the capillary phenomenon can cause moisture to collect in the contact area, see Figure 54. This will cause subsequent wear and early failure at rust spots. Reasons: improper storage in the warehouse (relative air humidity> 60%) drastic changes in temperature (moisture condensation) seal failure (accelerated by the abrasive action of dust, Fig. 87) Unsuitable lubricant remedies: according to rolling bearing manufacturer Properly store the instructions to improve the seal (add additional protection as much as possible). Use a lubricant with anti-corrosion agent to frequently re-lubricate bearings that use grease, especially before a long-term shutdown. 53: Corroded deep groove ball The outer ring of the bearing, its anti-rust protection is destroyed by moisture. Corrosion dents distributed on the raceway at the distance of the rolling elements Corrosion phenomenon caused by the intrusion of the medium: usually black corrosion dents, see Figure 55. Reason: Inappropriate storage in the warehouse (corrosive chemicals are stored in the same place). Seal failure. Unsuitable lubricants should be stored in accordance with the rolling bearing manufacturer’s instructions. Improve sealing. Use lubricants with anti-rust properties. 55: Due to intrusion Surface damage caused by sexual media. Corroded dents are often black.