PURPOSE: To make it possible to coat a quickly-drying lubricant film on a mandrel which has passed through a cooling bath by using an aqueous dispersion containing a natural or synthesized graphite, a clay mineral from the smectite class, a polysaccharide (a derivative) and a nonionic surfactant.

CONSTITUTION: An aqueous dispersion having 20-40 wt.% of a solid material content is prepared by dispersing 60-95 wt.% of a natural graphite having a crystal size of not less than 100 nm and an ash content of not more than 5% or a synthesized graphite having a crystal size of not less than 100 nm and a purity of not less than 99.9%, 5-40 wt.% of a clay mineral from the smectite class, 0.2-2 wt.% of a polysaccharide (a derivative) and 0-5 wt.% of a nonionic surfactant into water.