Most greases are
used for lubrication and are called antifriction greases. Anti-friction grease is mainly used to reduce mechanical friction and prevent mechanical wear. At the same time, it also plays a protective role against metal corrosion and a seal against dust. Some greases are mainly used to prevent metal from rusting or corroding. They are called protective greases. For example, industrial petroleum jelly has a small number of greases for sealing purposes, called sealing greases, such as thread grease. Most greases are semi-solid materials with unique fluidity.
The working principle of the grease is that the thickener keeps the oil in the position where it needs to be lubricated. When there is a load, the thickener releases the oil, thus playing a lubrication role.
At normal temperature and at rest, it looks like a solid, can keep its shape without flowing, and can adhere to metal without slipping. When high temperature or external force exceeds a certain limit, it can flow like a liquid. When the grease is sheared by the moving parts in the machine, it can generate flow and lubricate, reducing friction and wear between moving surfaces. When the shearing action stops, it can restore a certain consistency, and this special fluidity of the grease determines that it can be lubricated in places that are not suitable for use with lubricating oil. In addition, because it is a semi-solid substance, its sealing effect and protection are better than that of lubricating oil.