When choosing lubricating grease, the main considerations are the working conditions of the friction pair (load, speed, temperature), the working state (continuous operation, intermittent operation, vibration and impact, etc.), and the working environment (humidity, temperature, air pollution, etc.).
The use temperature of lubricating grease should be at least 20-30 degrees below its drip point
When using at high temperatures, lipids with good antioxidant properties, low evaporation losses, and high drop points should be selected; When using at low temperatures, it is recommended to choose lipids with low starting distance and similar low viscosity, such as those based on synthetic oil.
The selected lubricating grease should be suitable for the speed of use of the lubricated friction
At high speeds, lubricating grease with high cone penetration made of low viscosity base oil should be selected; For low-speed grease, high cone penetration grade lubricating grease made from high viscosity base oil should be selected.
The selected lubricating grease should be suitable for the load size
When under heavy load, lubricating grease with high viscosity of base oil and high content of thickener should be selected. When the load is particularly high, attention should be paid to selecting lubricating grease with extreme pressure additives or fillers (molybdenum disulfide, graphite); When operating at medium to low loads, it is generally recommended to use lubricating grease with a short soap fiber structure and medium viscosity as the base oil.
The selected lubricating grease should be suitable for the environmental conditions used
In environments with humid air or contact with water, lipids with good water resistance such as calcium based, lithium based, and composite lithium based should be selected; When there is a lot of dust, thicker and harder (i.e. higher grade) fats should be chosen. This has better sealing performance and can prevent impurities from entering the friction pair. In a strong chemical medium environment, synthetic oil lubricating grease such as fluorocarbon lubricating grease that is resistant to chemical media should be selected.
The selected lubricating grease should be compatible with the grease supply method of the friction pair
When it comes to centralized grease supply, lubricating grease from 00 to 1 should be selected; For parts that are regularly lubricated with grease guns, grease cups, etc., lubricating grease of grades 1-3 should be selected; For parts that are used for a long time without changing the grease, No.2 or No.3 lubricating grease should be selected.
The selected lubricating grease should be compatible with the working state of the friction pair
When there is significant vibration, use grease with high viscosity, good adhesion, and vibration damping properties, such as composite soap based grease thickened with high viscosity cyclic or mixed base lubricating oil.
7. The selected lubricating grease should be suitable for its intended use
The specific selection of grease for lubrication should be based on the type, working condition, working state, environmental conditions, and grease supply method of the friction pair; For protective grease, it should be able to effectively protect metals from corrosion, such as protecting parts in contact with seawater. Aluminum based grease with strong adhesion and water resistance should be selected; Generally, protective grease can be made from solid hydrocarbon thickened high viscosity base oil. For sealing grease, attention should be paid to its resistance to the solvent of the sealed medium.
The selected lubricating grease should minimize the variety of grease as much as possible to improve economic efficiency
When meeting the requirements, try to use multi effect universal lubricating grease such as lithium based grease, composite soap based grease, polyurea grease, etc. In this way, the variety of fats is reduced, the management of fats is simplified, and the long service life of multi effect fats can reduce the cost of using fats and repair costs.
