Carbon Bush Bearings

Carbon graphite bushes are used where the temperature is more than 400° F. It is mostly suited where there is corrosive environment, locations inaccessible for thermal lubrication, dusty environment where bearings & lubricants would require protection.

In the recent times Graphite Carbon Bushes have replaced conventional bushes and rings of steel for a variety of reasons –

• Graphite Bushes are Self Lubricating and is ideal where thermal lubricants cannot be used. High temperature is not a problem. Machining on CNC machine to a tolerance of 0.013 mm is easily done. It protects the bearings and provides a smooth surface and has a polishing effect.

• Very low co-efficient of friction and thermal expansion

• Resistance to corrosion, chemicals and oxidation

• Low density

• Excellent thermal shock

• Good mechanical strength

• High temperature resistance 

Trouble Shooting-

• Grit- Any kind of impurities like sand, granules, water particles, oil, dust present in the air can cause breakage of bushes

• Prolonged idle time/inactivity- Inactivity results in migration of the lubricants away from the bearing area and eventually hardens the lube that remains. When the machine is restarted metal to metal contact occurs immediately which causes breakage of bushes

• Frequent starts & stops can lead to dry running. If a bearing is immobile for a month or more, the bushes break due to absence of lubricating activity

• Vibration- even moderate vibration can shorten bearing life

• Corrosives & large loads can lower bearing lubrication

• Improper/Misalignment – Prevents smooth action of bearings and can cause burrows on the shaft or on the bearings in a matter of months

• Solutions used in pulp mills can turn perfectly good steel parts, self lubricated bushings into pitted relics in a very short period. Fluids, semi-fluids passing through pumps and mixers can dissolve bearing lubricants