When a rolling bearing is damaged during machine operation, the entire machine or equipment can seize or malfunction. Since bearings that fail prematurely or unexpectedly cause trouble, it is important to be able to identify and predict failure beforehand, so that preventive measures can be adopted. 

Damage Condition

Bearing rust and corrosion are pits on the surface of rings and rolling elements and may occur at the rolling element pitch on the rings or over the entire bearing surfaces.

Possible Causes

Entry of corrosive gas or water Improper lubricant Formation of water droplets due to condensation of moisture High temperature and high humidity while stationary Poor rust-preventive treatment during transporting Improper storage conditions Improper handling

Countermeasures

Improve the sealing mechanis Study the lubrication method Anti-rust treatment during periods of non-running Improve the storage methods Improve the handling method

Rust and Corrosion 1

Part: Outer ring of a cylindrical roller bearing
Symptom: Rust on the rib face and raceway surface
Cause: Water entry

Rust and Corrosion 2

Part: Outer ring of a slewing ring
Symptom: Rust on raceway surface at ball pitch intervals
Cause: Moisture condensation during stationary periods

Rust and Corrosion 3

Part: Inner ring of a spherical roller bearing
Symptom: Rust on raceway surface at roller pitch intervals
Cause: Entry of water into lubricant

Rust and Corrosion 4

Part: Rollers of a spherical roller bearing
Symptom: Pit-shaped rust on rolling contact surface. Corroded portions.
Cause: Moisture condensation during storage

Source: NSK