The chain (silent chain, roller chain or single-link chain) should be lubricated wherever it is used.Transmission chain requires lubricating oil to have good oiliness and permeability, can be firmly adsorbed on the inner and outer surfaces of the chain, can penetrate into each friction link of the chain, and will not be thrown off by the centrifugal force of the chain or be squeezed out of the friction surface.For general low-speed chains, 30# mechanical oil can be used.Low-speed chains for heavy equipment can also use open gear oil or grease.