Functions of Lubricating Grease

Lubricating grease primarily serves three core functions: lubrication, protection, and sealing.

Most greases are designed for lubrication and are referred to as anti-friction greases. Their main role is to reduce mechanical friction, prevent wear and tear on equipment, while also providing anti-corrosion protection and a sealing effect against dust and contaminants. Some greases are formulated mainly to prevent rust or corrosion on metal surfaces and are known as protective greases, such as industrial petroleum jelly. A small category of greases is specially used for sealing purposes and is termed sealing greases, like thread compounds.

Lubricating grease typically exists in a semi-solid state, giving it unique flow characteristics.

How Grease Works

Grease works by using a thickener to hold the oil in place at the lubrication point. Under load or pressure, the thickener releases the oil to provide lubrication.

At room temperature and under static conditions, grease behaves like a solid—maintaining its shape without flowing and adhering firmly to metal surfaces. Under high temperatures or when subjected to forces beyond a certain threshold, it flows like a liquid. When machinery operates and applies shear force to the grease, it flows to lubricate moving parts, reducing friction and wear. Once the shear force stops, the grease returns to its original consistency.

This unique flow behavior enables grease to perform effectively in applications where liquid lubricants are unsuitable. Additionally, due to its semi-solid nature, grease generally offers superior sealing and protective performance compared to lubricating oils.