Lubrication plays a crucial role in the normal operation of mechanical equipment.

(1) Reduce friction coefficient

Adding a lubricant between two surfaces with relative friction forms a friction-reducing film of oil, which can lower the coefficient of friction, reduce frictional resistance, and minimize power consumption. For instance, under good liquid friction conditions, the coefficient of friction can be as low as 0.001 or even lower. At this point, the frictional resistance is mainly the low shear resistance caused by the relative sliding of molecules within the liquid lubricating film.

(2) Reduce Wear

Lubricants nourish wear caused by hard particle wear, surface rust, and welding and tearing between metal surfaces. Therefore, supplying sufficient lubricant between friction surfaces creates optimal lubrication conditions, prevents oil film damage, maintains component fit accuracy, and significantly reduces wear.

(3) Reduce Temperature

Lubricants reduce friction coefficients and prevent the generation of frictional heat. We know that the work done by running machinery to overcome friction is completely transformed into heat. Some of this heat dissipates outward from the machine, while the rest continuously raises the mechanical temperature. By using a centralized circulating lubrication system with liquid lubricants, the heat generated by friction can be carried away, effectively cooling the machinery and ensuring it operates within the required temperature range.

(4) Corrosion Prevention & Surface Metal Protection

Mechanical surfaces inevitably come into contact with surrounding media (such as air, moisture, vapor, corrosive gases, and liquids), leading to rust, corrosion, and ultimately damage to the metal surfaces of machinery. This is especially true for high-temperature workshops in metallurgical factories and the severe corrosive wear in chemical plants.

(C) Cleaning Flush Action

Friction particles or foreign materials generated during the movement of friction pairs accelerate wear on the friction surface. By utilizing the fluidity of liquid lubricants, abrasive particles between friction surfaces can be carried away, thereby reducing particle wear. In pressure circulation systems, the flushing effect is more pronounced. In processing technologies such as cold rolling, hot rolling, cutting, grinding, and drawing, the use of process lubricants not only provides cooling and heat dissipation but also exhibits excellent flushing action, preventing solid impurities from scratching the surface of the finished product (steel). For example, by adding suspended dispersant additives to the lubricating oil used in internal combustion engine cylinders, the gel and carbon deposits formed in the oil are washed off the cylinder walls, dispersed into small particles, and then filtered out with the circulating oil, maintaining oil cleanliness, reducing cylinder wear, and extending oil change intervals.

(6) Sealing Function

Cylinders and pistons of steam engines, compressors, and internal combustion engines, among others, are not only lubricated to reduce friction and wear but also enhance sealing, ensuring no gas leakage during operation and improving work efficiency. Grease plays a special role in forming seals, preventing moisture, dust, or other impurities from infiltrating the friction components. For instance, using oil-impregnated packing coated with grease on a pump shaft head provides excellent lubrication and also prevents leakage and the entry of dust and impurities into the pump body, thereby ensuring a good sealing effect.

Furthermore, lubricants also have the capability to reduce vibration and noise.