Brief introduction to the main causes and countermeasures of bearing failure

1. Oxidation corrosion. When bearings are contaminated by water, old oil, hydraulic fluid or corrosive additives, they are easily oxidized by acidic substances in the contaminants, causing oxidation corrosion, resulting in a large amount of rust or pits. To effectively avoid this situation, the bearings should be cleaned and old lubricating oil should be removed before installation, and water should be avoided from contacting the bearings.

2. Fretting corrosion. When microscopic displacement occurs between the bearing ring and the rolling element, the bearing will cause fretting corrosion, and an oxide layer will appear on the outer surface of the bearing. To effectively avoid this situation, the bearing accuracy should be checked before installing the bearing. The bearing ring and the shaft should generally have an interference fit. If the accuracy is not enough and the interference fit is not available, fretting will occur. Interference fit will make installation more difficult. Anti-fretting paste and induction heater should be used to install the bearing on the shaft.

3. Microvibration friction and abrasion. When the bearing is static, vibration or oscillation will damage the oil film, and corrosion caused by friction between the rolling element and the raceway. To avoid this, the bearing must be placed flat when storing it, and avoid storing the bearing near the vibration source, such as a compressor or a vibrating device.

4. Surface peeling. When the bearing is insufficiently lubricated or the oil film is broken, small, extremely fine and hard particles will wear the bearing and cause the bearing surface to peel off. To prevent this from happening, the bearing should choose a suitable lubricant (quantity and viscosity) and an automatic lubrication system. During and after the bearing is installed, avoid the intrusion of solid particles and liquids, and check the bearing temperature.

5. Deep peeling of the surface. When the bearing is contaminated with solids, or corrosive liquids enter the bearing, and the housing or shaft is misaligned or deformed, bearing surface defects (indentation, impact, corrosion, excessive stress, etc.) will cause deep peeling. To prevent this from happening, avoid introducing contaminants when installing the bearing, and control the geometry and quality of the valve seat to avoid stress caused by bearing misalignment.

6. Deep spalling of the inner lining. When the bearing is subjected to cyclic stress, the bearing will produce deep spalling of the inner lining, which is usually elliptical spalling. To prevent this damage, ensure that the bearing is compatible, use a monitoring system on the equipment to detect vibration and noise associated with the spalling caused by fatigue, and follow a predictive maintenance plan for bearing replacement.

7. Plastic deformation. When the bearing is not installed correctly or is severely short-circuited and overloaded, plastic deformation will occur, and pits will be produced on the raceway. To prevent this, the bearing should be installed using the correct installation method and tools, while ensuring that the rolling elements do not transmit static overloads.

8. Fracture. When the bearing is subjected to impact, overload, bending force, fatigue or excessive thermal stress, the bearing will suddenly break. To avoid this damage, check the condition of the bearing seat before installation, use the correct installation method and tools to install the bearing, and never hit the bearing directly with a hammer. Noisy bearings should be replaced quickly during use.

9. Wear with particles. This happens when there is wear of solid particles in the boundary lubrication of the bearing, and matte surfaces, streaks or pits will appear on the rolling shell and raceway. To avoid this, the bearing should use clean lubricants to fully lubricate the bearing, and select appropriate sealing devices, such as dust covers, or seals.

10. Friction wear. When the bearing temperature rises and causes significant sliding, the metal components welded to each other will rub and produce friction wear. To prevent this from happening, the appropriate lubricant should be used according to the quantity and quality, and the appropriate bearing should be used according to the load and speed.

11. Spalling caused by axial overload. When the axial load of the bearing is too large, spalling will occur on one side of the bearing raceway. To avoid this, the bearing should be selected correctly and the floating bearing should be checked to see if it can move freely.