High Temperature Bearing Grease: Meaning and Selection
What is ‘High temperature bearing grease’?
As the name suggests ‘High’ means extreme. It is a type of mineral oil based grease. It is made suitable for the equipment operating at high temperatures. Its application range is wide which includes electric motors, industrial fans, wheel bearings, and pumps.
For example, machinery operating at, let us assume 800 degrees Celsius requires grease to ensure that its parts remain secure and lubricated all the time during the operation. In such cases, an ordinary grease would be converted into vapor leaving the risk of failure in some specific part or the whole system.
High temperature bearing grease is made of different compounds than any ordinary grease and therefore it remains unchanged during operation at high temperatures. It continuously keeps on lubricating the machine parts, ensuring their safety.
Its selection affects many factors. The selection should be made very precise and should consider important factors such as oil type, viscosity index, price, etc. if the selection is wrong then following may happen.
- There will be unwanted friction between machine parts.
- The bolts or other connections stretch out and weaken.
- Failure of machine parts.
- During any maintenance screws and bolts may break away causing the shutdown of the machine.
The market is full of different types of greases which are manufactured to operate at a particular temperature or on specific equipment. The user may get confused with the names and specifications available in the market.
The user should thoroughly study the final use of grease. He should understand the effect of the composition of grease. The base oil concentration affects largely on the characteristics of grease.
The dropping point test
This test is done to measure the characteristic of grease in numbers. The dropping point of a soap-thickened lubricating grease is the temperature at which it passes from a semisolid to a liquid state under specific test conditions. It is an indicator of the heat resistance of grease. It is seen that few greases return to their original form or structure after cooling from dropping point.