Causes and Dangers of Rust in Rolling Bearings
When the bearing surface loses its luster and appears dark black, it indicates rust. Severe rust often appears as yellow-brown or reddish-brown flaky spots.
There are seven reasons for bearing rust:
1. Bearings are not installed promptly after cleaning, leaving them exposed to air and moisture for extended periods, causing them to become contaminated and irritated.
2. Bearings are not cleaned properly, allowing grinding wheel dust, dust, and dirt to adhere to the surface.
3. Handling bearings with sweaty hands.
4. Careless installation or impacting bearings, causing dents and scratches on the bearing surface.
5. Rust inhibitors are ineffective or substandard.
6. Defective seals in bearings during use allow moisture and dirt to enter.
7. Bearings are left unused for extended periods of time and lack proper maintenance.
Rust is very harmful to bearings. When rust occurs on the bearing assembly surface, it can easily scratch the bearing's inner and outer diameters, journal, and housing bore, affecting fit accuracy, accelerating bearing wear, and causing loosening and resulting in failure. When rust occurs on the bearing's working surface, or when rust settles onto the working surface, it can cause intense abrasion between the bearing ring raceways and rolling elements, increasing bearing clearance and affecting the accuracy and service life of the main engine.
If bearing rust is detected, it should be promptly removed. If the rust is severe and poses a threat to the bearing, it should be removed and replaced with a new bearing.