What are the differences and functions of grease and oil?

What are the differences and functions of grease and oil?

Lubricating oil is a liquid lubricant used to reduce friction on various types of machinery. Its main functions include cleaning, sealing, lubrication, cooling, rust prevention and buffering.

Grease, also called “butter”,  is a thick, oily semi-solid, which is also used in the friction part of the machinery to lubricate and seal. It is also usually used to fill gaps and prevent rust on metal surfaces. The composition of grease includes synthetic lubricants and thickeners. One of the functions of grease is to prevent metal corrosion or rust, and it is called protective grease. At common temperature and static state, it will not flow like a solid, but when it is subjected to external force or high temperature, it can flow like liquid. When the grease is sheared by the accessories in the machine, it will flow and lubricate, reducing the wear and friction between the moving parts. When the shearing stops, it returns to a certain consistency. The special fluidity function of grease allows it to lubricate parts that are not suitable for lubricating oil.

In addition, the protection and sealing effects of grease are better than those of lubricating oil because it is a semi-solid substance.