Lubricating grease is used for the friction part of machinery to lubricate and seal. It is also used on metal surfaces to fill gaps and prevent rust. It is mainly made of mineral oil or synthetic lubricating oil and thickener. Most greases are used for lubrication and are called antifriction greases. Antifriction grease is mainly used to reduce mechanical friction and prevent mechanical wear. At the same time, it also plays the role of protection against metal corrosion and sealing and dust prevention. Some greases are mainly used to prevent metal from rusting or corrosion, which is called protective grease. Some greases are specially used for sealing, which is called sealing grease. Lubricating grease is mostly a semi-solid substance with unique fluidity. The working principle of lubricating grease is that the thickener keeps the oil at the position that needs lubrication. When there is load, the thickener releases the oil, thus playing a lubricating role. There are some main performance indexes of lubricating grease used in construction machinery, which will be summarized in this article.
1. Drip point
It refers to the temperature when heating under specified conditions and reaching a certain fluidity. It can generally determine the service temperature of grease.
2. Cone penetration
It refers to the depth that the test cone freely and vertically penetrates into the grease within 5S under the specified temperature and load (unit: 1/10mm). It is a measure of the consistency and hardness of lubrication.
3. Colloidal stability (oil precipitation)
It refers to the ability of lubrication under the action of external force to preserve oil in the framework of its thickener, which is determined by the amount of oil. When the oil separation amount of lubricating grease exceeds 5%-20%, this lubricating grease can basically not be used.
4. Oxidation stability
It refers to the ability to resist oxidation during storage and use.
5. Mechanical stability
Refers to the ability to resist consistency changes under mechanical working conditions. Poor mechanical stability is easy to cause the consistency of grease to decrease.
6. Evaporation loss
It refers to the percentage of its loss in the total under the specified conditions. It is an important factor affecting the service life of lubricating grease.
7. Water resistance
It refers to the ability not to dissolve in water, not to absorb water from the surrounding medium and not to be washed away by water.
8. Similar viscosity
It refers to the ratio of shear stress to shear velocity when non-Newtonian fluid flows. When the rotating speed is high, its viscosity is low, otherwise, its viscosity is large.
