The document discusses 5 common types of bearing damage: 1) Abrasive wear from contamination like sand or fine metal particles, 2) Pitting and bruising from hard particles, 3) Grooving from heavy wear from chips or metal particles, 4) Corrosion from lack of protection from moisture, and 5) Inadequate lubrication, which can cause issues ranging from discoloration to total bearing lockup.

1. 5 COMMON TYPES OF
BEARING DAMAGE
PRESENTED BY
&

2. W E A R – A B R A S I V E
C O N TA M I N AT I O N
Fine foreign material in
the bearing can cause
excessive abrasive wear.
Sand, fine metal from
grinding or machining,
and fine metal or
carbides from gears
wear or lap the rolling
elements and races.

3. W E A R – P I T T I N G A N D
B r u i s i n g
Hard particles rolling through the bearing may cause pitting
and bruising of the rolling elements and races. Metal chips
or large particles of dirt remaining in improperly cleaned
housings can initiate early fatigue damage.

4. W E A R – G R O O V I N G
Extremely heavy wear from chips or metal particles can cause
grooving. These contaminants become wedged in the soft cage
material and cut grooves in the rolling elements. This condition
generates improper rolling contact geometry and can reduce service
life.

5. E T C H I N G - C O R R O S I O N
Etching (or corrosion) remains one of the most serious
problems anti-friction bearings encounter. Without adequate
protection, the high degree of surface finish on races and
rolling elements makes them susceptible to corrosion
damage from moisture and water.

6. I N A D E Q U AT E
L U B R I C AT I O N
Inadequate lubrication can create a wide range of damage
conditions. Damage happens when there isn’t a sufficient
amount of bearing lubricant to separate the rolling and
sliding contact surfaces during service.
Level 1 – Discoloration
• Discoloration due to elevated
operating temperature

7. I N A D E Q U AT E
L U B R I C AT I O N
Level 2 – Scoring and Peeling
• Insufficient or complete lack of lubricant.
• Selecting the wrong lubricant or lubrication type.
• Temperature changes.
• Sudden changes in running conditions.

8. I N A D E Q U AT E
L U B R I C AT I O N
Level 3 – Excessive Roller End Heat
• Inadequate lubricant film results in localized high
temperatures and scoring at the large ends of the
roller

9. I N A D E Q U AT E
L U B R I C AT I O N
Level 4 – Total Bearing Lockup
• High localized heat produces metal flow in bearings, altering the
original bearing geometry and the bearing’s material.
• This results in skewing of the rollers, destruction of the cage,
metal transfer and complete seizure of the bearing.