Pitting (rolling bearing damage)

Pitting is a term that describes a specific type of damage that can occur in rolling bearings. It refers to the formation of small indentations or pits on the raceways and rolling elements of the bearing. This damage is caused by material fatigue or surface loads that exceed the load limits of the material.

Causes of pitting

• Fatigue: Repeated loading and stresses lead to the formation of microcracks in the material, which expand into larger pits over time.

• Incorrect lubrication: Insufficient lubrication or the wrong lubricant can lead to metal-to-metal contact, which damages the surface.

• Contamination: Dirt particles or foreign bodies in the bearing can cause pressure peaks and damage the surface.

• Overload: If the bearing is subjected to a higher load than specified, this can lead to pitting.

• Corrosion: Chemical influences or moisture can weaken the material structure and promote the formation of pitting.

• Misalignment: Incorrect mounting or misalignment of the bearing creates uneven loads that promote pitting.

Types of pitting

• Initial pitting:
• Occurs early in the operating cycle of a bearing.
• Mostly superficial and can stabilize during operation by smoothing the surface.
• Progressive pitting: 
  • Severe form in which the pits become larger and spread further.
  • Leads to progressive material loss and damage to the bearing.

Effects of pitting

• Increased vibrations and noise: The pits on the surface lead to irregular running.
• Reduced service life: The bearing wears out more quickly and must be replaced.
• Loss of performance: Pitting impairs the load capacity and efficiency of the bearing.

Measures for prevention

• Selecting the correct bearing: Ensure that the bearing is suitable for the loads and ambient conditions present.
• Optimum lubrication: Use of a suitable lubricant that can cope with the loads and temperatures.
• Cleanliness: Protection against dirt and foreign bodies thanks to high-quality seals.
• Mounting accuracy: Precise installation to avoid misalignment.
• Regular maintenance: Inspection and relubrication to detect early signs of damage.

Preventing pitting is important to maximize the service life and reliability of rolling bearings. A well-maintained bearing can contribute significantly to the efficiency of machines.

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