1. Bruises

The scratch is the surface damage that caused by the small burns and caused by rolling skidding and oil film hot cracking on the raceway surface and rolling surface.

A rough surface with adhesion is produced. The main causes of bruises are high speed and light load, rapid acceleration and deceleration, inappropriate lubricant, water invasion and so on.

Solutions: improve preloading, improve bearing clearance, use lubricant with good oil film, improve lubrication method, and improve sealing device, etc.

2. Indentation

When the metal powder or foreign body is bitten, the indentation on the raceway surface or rotating surface or due to the impact of installation, the concave surface (Brinell hardness indentation) is formed at the spacing of the rolling body.

The main factors causing indentation include metal powder and other foreign bodies bite, assembly or transportation process subjected to excessive impact load and so on.

Solutions: improve sealing device, filter lubricating oil, improve assembly and use methods, etc.

3. Burn

Raceways, rollers and cages heat sharply during rotation until they change color, soften, deposit and break. The causes of burn are poor lubrication, excessive load (too large preloading), too large rotating speed, too small clearance, invasion of water and foreign bodies, poor accuracy of bearing box, large deflection of shaft and so on.

It can be solved by improving lubricant and lubrication method, correcting bearing selection, studying coordination, bearing clearance and preloading, improving sealing device, checking the accuracy of shaft and bearing box or improving installation method.

4. Current corrosion

The electric erosion refers to the local melting and concave and convex phenomenon when the current flows through the thin lubricating oil film when the current flows in the contact part of the bearing ring and the rolling body in rotation.

The main causes of current corrosion are the potential difference between the outer ring and the inner ring and the action of static electricity.

Solution: when setting the circuit, the current does not pass through the bearing, insulation of the bearing and electrostatic grounding.