Roll gap lubricating method for producing ultrathin hot rolling strip steel with semi-endless rolling technology

The invention discloses a roll gap lubricating method for producing ultrathin hot rolling strip steel with a semi-endless rolling technology. The opening of an electromagnetic control valve is controlled so that 50-100 ml of lubricating oil flows through an oil supply pipe and enters an oil-water mixer every minute; the opening of a water quantity regulation control valve is controlled so that 40-60 L of circulating water flows through a water supply pipe and enters the oil-water mixer every minute; and the oil-water mixture in the oil-water mixer is injected to the roll surfaces of an upper working roll and a lower working roll through a nozzle on a spraying header respectively. The first rolling mill and the seventh rolling mill are not lubricated in the hot rolling process of strip steel, and the head and tail of the strip steel are not lubricated. When the head of the strip steel reaches the next rolling mill, the electromagnetic control valve on the previous rolling mill is opened; and when the tail of t