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. When selecting lubricating grease, the working condition, working state and working environment of friction pair should be mainly considered. This article will summarize four judgment methods for selecting lubricating grease. Due to the different requirements of various brands, the methods mentioned in this article are for reference only.
1. The service temperature of lubricating grease should be at least 20~30 degrees below its dropping point
When using at high temperature, grease with good oxidation resistance, small evaporation loss and high drop point should be selected. When the service temperature is low, the lubricating grease with low starting torque and similar viscosity should be selected, such as the lubricating grease with synthetic oil as the base oil.
2. The selected grease should be suitable for the service speed of the lubricated friction pair
At high speed, grease with large cone penetration made of low viscosity base oil should be selected. For the lubricating grease used at low speed, the lubricating grease with high penetration grade made of high viscosity base oil should be selected.
3. The selected grease should be suitable for the load.
Under heavy load, lubricating grease with high viscosity of base oil and high content of thickener should be selected. When the load is particularly large, attention should be paid to the selection of lubricating grease with extreme pressure additives or fillers. At medium and low load, the lubricating grease of No. 2 consistency soap base oil with short fiber structure and medium viscosity is generally selected.
4. The selected grease should be suitable for the environmental conditions used
When the air is humid or in contact with water, grease with good water resistance such as calcium base, lithium base and composite lithium base should be selected. When there is much dust, choose a thicker grease. In this way, the sealing performance is good, and impurities can be prevented from mixing into the friction pair. In the environment of strong chemical medium, synthetic oil lubricating grease with anti chemical medium such as fluorocarbon grease should be selected.
