Lubricating system and cast rolling system

The lubricating system comprises an oil supply pipeline, a water supply pipeline, an oil-water mixing pipeline, a spraying assembly and a metering assembly, in the using process, lubricating oil is supplied to the oil-water mixing pipeline through the oil supply pipeline, and water is supplied to the oil-water mixing pipeline through the water supply pipeline; lubricating oil and water are mixed between the oil-water mixing pipelines, a first spray head and a second spray head of the spraying assembly face an upper working roll and a lower working roll of the four-roll mill respectively, the mixture of the lubricating oil and the water enters a deformation area under the rotation action of the upper working roll and the lower working roll, and a layer of ultra-thin oil film is formed on the surfaces of the rolls and rolled metal. The oil film changes the deformation condition of a deformation area, reduces rolling force, saves energy consumption, reduces roller abrasion, improves product surface quality, impr