Bearing erosion

Erosion or corrosion is one of the most serious problems encountered in friction resistant bearings.The high precision machining of bearing raceway and roller surface makes them vulnerable to corrosion by moisture and water.
Erosion is usually caused by the temperature change in the bearing housing, condensation of the internal air, and the accumulation of moisture.Moisture or water often enters the bearing from damaged, damaged, or improper seals.In addition, improper cleaning and drying of bearings during disassembly and inspection can also cause such damage.After the bearing is cleaned and dried, or when the bearing is placed in the warehouse, it should be coated with lubricating oil or other preservatives and packed in protective paper.Both new and old bearings should be placed in dry areas with original packing to reduce the possibility of static corrosion before installation.

• Insufficient bearing lubrication

  Inadequate lubrication can be used to describe many possible damage conditions.A common feature of these cases is that the lubricant is not sufficiently isolated from the bearing’s rolling and sliding contact surfaces during the bearing operation.For different bearing systems, it is important to correctly design the amount, type, grade, supply system, viscosity and additives of the lubricant required, based on experience, load, speed, sealing system, operating conditions and life expectancy.If these factors are not properly considered, the bearing performance and its operating performance may not achieve the desired effect.
  Bearing damage due to inadequate lubrication can vary from very slight thermal discoloration with large roller scratches to integral locking of the bearing with extreme metal distortion.There is also a case where the bearing is subjected to a dry start, accompanied by extreme metal distortion, but the surface remains bright;This happens occasionally.This is because during the start-up phase, the bearing suffers heat damage due to metal-to-metal contact, and then, once the lubricant reaches the bearing, the bearing eventually cools down.The bearings then attempt to “repair” themselves to disguise the initial metal distortion and thermal discoloration.
  Secondary damage is more pronounced and often conceals the initial problem and subsequent bearing damage.This type of bearing damage typically results in high local heat and metal flow within the bearing, thereby altering the original bearing geometry and material.Any visible metal crack, scratch, heat mark, deformation or geometric change will render the bearing useless and unusable.

  Bearing overload

  Excessive preloading will generate a lot of heat and lead to bearing damage.The form of damage is similar to that caused by insufficient lubrication in appearance.These two triggers are often confused, so a thorough examination is needed to determine the root cause of the problem.Lubricants suitable for general operation may not be suitable for bearings with high pre-loads because the oil film may not be strong enough to carry ultra-high loads.
  Another form of damage may occur under high preloads, even when extreme pressure lubricants capable of carrying heavy loads are used.Although the lubricant can cope with the load and prevent scratches to the rolling members or raceway, heavy load may cause premature fatigue flaking of the secondary surface layer.The occurrence of this type of spalling and the consequent bearing life problems will depend on the bearing’s pre-load and bearing capacity.

  • Bearing operation and installation

    Care should be taken in the operation and assembly of the bearing to avoid damage to the rolling body, raceway surface and edges.If there is a deep gouge on the surface of the raceway, or if the rolling body is impacted or deformed, the metal near the damaged area will be raised accordingly.When rolling members pass through these damaged surfaces, high stress is generated and local premature peeling occurs.The direct effect of gouging and deep marking is to make the bearing rough and produce vibration and noise.