Powder metallurgy bearing is made of metal powder and other antifriction material powder pressed, sintered, plastic and soaked. It has porous structure. After the infiltration of hot oil, the pores are filled with lubricating oil. In the process of working, the metal and oil are heated and expanded, and the oil is squeezed out of the pores. The friction surface is lubricated. After the bearing is cooled, the oil is sucked back into the pores.

Powder metallurgy bearings can not be lubricated for a long time.

The higher porosity of powder metallurgy bearings, the more oil storage, but the more pores, the lower the strength.

Such bearings are often in the mixed lubrication state, sometimes can form thin film lubrication. They are often used to supplement the difficult and light load and low speed condition of lubricating oil.

According to different working conditions, powder metallurgy bearings with different oil content are selected. When the oil content is large, it can be used under no supplementary lubricating oil and low load. The oil content can be used under heavy load and high speed. The graphite bearing powder metallurgy bearing can improve the safety of the bearing because of the lubricity of graphite itself. Its disadvantage is that the strength is low. Under the condition of no corrosion, it can consider the selection of low price and strength. The iron base powder metallurgy bearing with higher degree is higher, but the corresponding shaft neck hardness should be appropriately improved.