We take a quick look at the function of grease and the important characteristics it should have.
As a young boy, I remember asking my father if grease was expensive. He told me it was the cheapest thing on the farm, referring to the implications of not using it! Greasing is a non-negotiable for achieving acceptable machine and component life. Grease should generally carry out the following functions:
- Reduce friction and wear in the machine element being lubricated under various operating conditions.
- Protect against rust and corrosion.
- Prevent dirt, water and other contamination from entering the part being lubricated.
- Maintain its structure and consistency during long periods of use.
- Allow free motion of moving parts at low temperatures and pump freely at those temperatures.
- Have suitable physical characteristics for the method of application and retain those characteristics during storage.
- Be compatible with the seals and other materials associated with the parts being lubricated.
- Tolerate or resist a small amount of moisture contamination without loss of performance.
To be able to do the above, grease should have the following characteristics:
- High temperature capabilities
- Low temperature capabilities
- Shear and mechanical stability
- Water resistance
- Oxidation resistance
- Rust and corrosion protection
- Variable speed conditions
- Good pumpability