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Causes Of Damage To FAG Bearings

Source:  skf bearing  Time:  2020-08-18

When FAG bearings are installed and used, the bearings are easily damaged due to internal and external factors. However, few people know the damage status and timely measures. Today, I will introduce the following reasons for the damage of FAG bearings and timely Rescue measures help extend the service life of bearings.


Peel off


Damage status: When the FAG bearing rotates under a load, the raceway surface or rolling surface of the inner ring and outer ring will show a fish-scale peeling phenomenon due to rolling fatigue.

Reason: The load is too large. Poor installation (non-linearity) moment load foreign matter intrusion and water ingress. Poor lubrication and improper lubricant FAG bearing clearance is inappropriate. The accuracy of FAG bearing box is not good. The uneven rigidity of FAG bearing box is caused by the development of rust, corrosion points, scratches and indentations (surface deformation phenomenon).

Measures: Check the size of the load and re-study the FAG bearing improvement installation method used to improve the sealing device and prevent rust during shutdown. Use lubricants of appropriate viscosity and improve lubrication methods. Check the accuracy of the shaft and FAG bearing housing. Check the clearance.




Damaged state: A dark surface with slight abrasion appears. There are many tiny cracks from the surface to the depth of 5-10m on the dark surface, and small peeling (micro peeling) occurs in a large area

Reason: The lubricant is not suitable. Foreign matter has entered the lubricant. Poor lubricant causes rough surface. The surface finish of the mating rolling parts is not good.

Measures: Choose a lubricant to improve the sealing device to improve the surface finish of the matched rolling parts.FAG Bearing 6207N online, click here to learn more details.




Damage status: The so-called seizure is the surface damage caused by the collection of small burns on the part of the sliding surface. Linear flaws in the circumferential direction of the slideway and rolling surfaces. The cycloid scar on the roller end surface is close to the jam on the collar surface of the roller end surface.

Reason: excessive load, excessive preload. Poor lubrication. Foreign body bites. Tilt of inner ring and outer ring, deflection of shaft. The accuracy of the shaft and FAG bearing box is poor.

Action: Check the size of the load. The preload should be appropriate. Improve lubricants and lubrication methods. Check the accuracy of the shaft and FAG bearing box.




Damage state: The so-called fracture refers to a small part of the raceway wheel rib or roller corner part of the impact or excessive load.

Reason: It was hit during installation. The load is too large. Bad use such as dropping.

Measures: Improve the installation method (using hot fitting, using appropriate tool holders). Correct the load conditions. FAG bearings are installed in place to support the ribs.


Cracks, cracks


Damage status: The so-called crack refers to the crack damage of the race wheel or rolling element. If you continue to use it, it will also include cracks developed by cracks.

Reason: excessive interference. Excessive load, shock load. The divestiture has developed. Heat generation and fretting wear due to the contact between the race wheel and the mounting member. Heat caused by creep. The taper angle of the taper shaft is bad. The cylindricity of the shaft is poor. The fillet radius of the shaft step is larger than the FAG bearing chamfer, causing interference with the FAG bearing chamfer.

Measures: The amount of interference is appropriate. Check the load conditions. Improve the installation method. The shape of the shaft should be appropriate.




Damaged state: When small metal powders, foreign objects, etc. are bitten into, the dents produced on the raceway surface or the rotating surface. Due to impact during installation, etc., a concave surface (Brinell hardness indentation) is formed in the pitch interval of the rolling elements.

Cause: foreign matter such as metal powder bites. The shock load received during assembly or transportation is too large.

Measures: Impact sleeve. Improve the sealing device. Filter the lubricating oil. Improve assembly and usage methods.


Fretting wear


Damage state: The wear caused by the relative repeated micro-sliding between the two contact surfaces is generated on the contact part of the raceway surface and the rolling element. Due to the occurrence of reddish brown and black wear powder, it is also called fretting corrosion.

Reason: poor lubrication. Rocking motion with small amplitude. Insufficient interference.

Measures: Use appropriate lubricants. Add preload. Check the interference. Apply lubricant to the mating surface




Damage state: The so-called creep refers to the relative sliding between the mating surfaces when there is a gap between the mating surfaces of the FAG bearing. The creeping mating surface presents a mirror-bright or dark surface, and sometimes the page is jammed Wear occurs.

Reason: insufficient interference or clearance fit. The adapter sleeve is not tightened enough.

Measures: Check the interference and implement stop-rotation measures. Properly tighten the adapter sleeve. Study the accuracy of the shaft and FAG bearing housing. Axial preload. The side of the raceway wheel is fastened. Bond the mating surface. Apply lubricant to the mating surface.Eric Bearing Limited provides FAG Bearing 6002.2RSR, click here for more information about it.




Damaged state: The raceway wheel, rolling element and cage heat up rapidly during rotation until they are discolored, softened, welded and damaged.

Reason: poor lubrication. Excessive load (excessive preload). The speed is too high. The clearance is too small. Intrusion of water and foreign objects. The shaft and FAG bearing box have poor accuracy and large shaft deflection.

Measures: Research lubricants and lubrication methods. Correct the selection of FAG bearings. Study the fit, FAG bearing clearance and preload. Improve the sealing device. Check the accuracy of the shaft and FAG bearing housing. Improve the installation method.


Electric erosion


Damaged state: The so-called galvanic corrosion refers to when the current flows in the contact part of the FAG bearing race wheel and the rolling element, the thin lubricating oil film emits sparks, and the local surface melting and unevenness appear on the surface.

Reason: the ground potential difference between the outer ring and the inner ring.

Measures: When setting the circuit, the current should not flow through the FAG bearing part. Insulate FAG bearings.


Rust, corrosion


Damage status: The rust and corrosion of FAG bearings include pit-like rust on the surface of the raceway wheel and rolling element, and overall rust and corrosion.

Reason: Intrusion of water and corrosive substances (paint, gas, etc.). The lubricant is not suitable. Water droplets are attached due to condensation of water vapor. Stopped in high temperature and humidity. Heavy rust prevention during transportation. The storage status is inappropriate. Use inappropriate.

Measures: Improve the sealing device. Research lubrication methods. Anti-rust measures when stopping. Improve storage methods. Be careful when using it.


Installation scars


Damage status: Axial linear scars on the raceway surface and rolling surface during installation and disassembly.

Reason: the impact load during installation and removal of the inner ring and outer ring when inclined installation and removal.

Measures: Use appropriate tools to use the punching machine to prevent impact loads. Centering between each other during installation.




Damage state: due to temperature rise and lubricant reaction, the raceway wheel, rolling element and cage are discolored.

Reason: poor lubrication. The reaction with the lubricant causes hot oil immersion. The temperature rises greatly.

Measures: Improve the lubrication method.