The lubricant is generally the product of petroleum fractional distillation and may also be refined from animal and vegetable oil and artificially synthesized.

Concept of lubricant: The lubricant is a liquid substance added between solid frictional contact surfaces with relative motion to form a lubricating film between the friction surfaces and to separate the friction surfaces directly contacted originally, so as to achieve the purpose of reducing friction, reducing wear, saving energy, reducing consumption and prolonging the equipment service life. As the blood of the machine, the lubricant determines the mechanical performance and life.

The lubricant is generally composed of base oil and additives. The base oil, as the main component of the lubricant, determines the basic properties of the lubricant; the additives, as an important part of the lubricant, can make up and improve the deficiencies in terms of base oil performance and give some new properties. The base oil of the lubricant is mainly classified into mineral base oil, synthetic base oil and biological base oil. The mineral base oil is widely used with the consumption of about more than 95%, but the products deployed by synthetic base oil and biological base oil must be used in some occasions, so that the synthetic base oil and biological base oil are developed quickly.

The mineral base oil is refined from crude oil. The main production processes of the lubricant base oil include atmospheric and vacuum distillation, solvent deasphalting, solvent refining, solvent dewaxing, clay finishing or hydro-finishing. The chemical components of mineral base oil include the mixtures of high boiling point and high molecular weight hydrocarbons and non-hydrocarbons and generally consists of alkanes (straight-chain, branched-chain and highly branched chain), cycloalkanes (monocyclic, bicyclic and polycyclic), aromatics (mononuclear aromatics and polycyclic aromatic hydrocarbons), naphthenic aromatics and non-hydrocarbons.

The biological base oil (vegetable oil), as a "natural" lubricant, is more and more popular because it can be biodegraded to reduce pollution to the environment.

The synthetic lubricants generate the required materials under manual control. With stable molecular structure, homogeneous components and excellent performance, this kind of lubricant can effectively meet the requirements for equipment development towards small volume, high power, high precision and automation and is increasing year by year in terms of use ratio and consumption.

Functions of lubricants/lubricating grease

1. Cooling: friction heat should be discharged at any time;

2. Antifriction and wear resistance: friction should be decreased to save energy and reduce wear so as to extend machine life and improve economic returns;

3. Seal: seal should be leekproof, dustproof and blow-by-resistance;

4. Anticorrosion and rust protection: the friction surface should be protected from erosion of oil oxidative deterioration substances or foreign matters;

5. Washing and rinsing: debris on the friction surface should be washed off;

6. Shock absorption: load diffusion and shock relaxation are required;

7. Kinetic energy transfer