Grease is a semisolid liquid that consists of a liquid lubricant mixed with a thickener. The oil does the lubricating while the thickener holds the oil and provides a resistance to flow. Soaps (a metallic element such as lithium, calcium, sodium, or aluminum reacted with a fatty acid) or fine particles of a lubricating additive, such as polytetrafluoroethylene (PTFE) or lead are used as thickeners in the grease. The consistency of grease is such that it can be cut using a knife and also can flow under low pressure. Similar to oil lubricants the additives are added to grease to improve load-carrying ability, oxidation resistance, and corrosion control.

Function of Grease

1. The main function of the grease is to remain intact on the surface to provide the lubrication for that surface without leaking under the affect of the gravity.

2. Grease should not lose its shear properties in presence of varying temperature.

3. Grease must flow through bearing through the grease gun, however it should not add as an additional agent to consume more power.

Functional Properties of Grease

1. It acts as a sealant and prevents leakage.

2. It has more advantages compared to oil.

3. It acts as a solid lubricant.

4. The fluid levels are not to be controlled or measured.