Failure forms of slide bearings

The main failure forms of sliding bearings include abrasive wear, adhesive wear (bonding), fatigue spalling, corrosion and other special damages, as follows: 

1. Abrasive wear

   After hard particles (such as dust and metal debris) enter the bearing gap, they grind the surface as the shaft rotates, causing the material to gradually wear, the gap to increase, and the performance to deteriorate prematurely. This type of wear is particularly obvious during startup, shutdown or contact with the edge of the journal.

2. Adhesive wear (bonding)

   When high temperature, overload or lubricating oil film rupture, the bearing and the journal surface material adhere and migrate, which may cause motion jamming or even shutdown in severe cases. For example, insufficient lubricating oil causes direct metal contact, forming local fusion welding.

3. Fatigue spalling

   Under alternating loads, fatigue cracks perpendicular to the sliding direction are generated on the bearing surface. After the cracks extend to the bonding surface, material spalling occurs. The edges of the spalling area are irregular, which is different from the smooth spalling caused by poor bonding.

4. Corrosion

   Acidic substances generated by lubricant oxidation or the external environment (such as moisture and sulfides) corrode the bearing material. For example, lead-based alloys are easily corroded by acidic substances to form point-like peeling, while tin-based alloys may form a hard oxide layer to scratch the journal.

5. Other damages

Cavitation: Fluid pressure changes cause bubbles to burst and impact the surface.

Electrical erosion: Current passing through the bearing causes local discharge corrosion.

Fretting wear: Oxidation and material loss of the contact surface caused by small vibrations.