The role of grease is mainly to lubricate, protect and seal。
The vast majority of greases are used for lubrication and are called antifriction greases。Antifriction grease mainly plays the role of reducing mechanical friction and preventing mechanical wear.At the same time, it also has a protective effect to prevent metal corrosion, and a sealing and dustproof effect。Some greases are mainly used to prevent rust or corrosion of metals, called protective greases。For example, a small number of greases such as industrial vaseline are specially used for sealing, called sealing greases, such as thread grease。Greases are mostly semi-solid substances with unique fluidity。
The working principle of grease is that the thickener keeps the oil in the position where it needs to be lubricated, and when there is a load, the thickener releases the oil, thus playing a lubricating role。
At room temperature and at rest, it is like a solid, can maintain its shape without flowing, and can adhere to the metal without slipping。At high temperatures or when subjected to external forces beyond a certain limit, it can flow like a liquid。When the grease is subjected to the shear action of moving parts in the machine, it can produce flow and lubricate, reducing friction and wear between moving surfaces。When the shearing action stops, it can recover a certain consistency, and this special fluidity of the grease determines that it can be lubricated in parts that are not suitable for lubricating oil。In addition, because it is a semi-solid substance, its sealing effect and protection are better than lubricating oil。
Grease is mainly composed of three parts: thickener, base oil and additive。The content of thickening agent in general grease is about 10%-20%, the content of base oil is about 75%-90%, and the content of additives and fillers is below 5%。