Lubrication is one of the most important factors for improving the productivity of tandem cold rolling mills, which increases the rolling speed for thin steel strips and prevents chatter when rolling materials with a high deformation resistance. A new hybrid lubrication system is proposed and its effectiveness is clarified. The system is based on a re-circulation system of coolant, combined with a system for flexible lubrication control. The key to realizing the new coolant system is the control of plate-out oil formation on a strip surface under high-speed rolling conditions. In this study, the plate-out oil film formation of emulsions is investigated, and the conditions for achieving sufficient plate-out oil films are clarified. Then, the time-dependent property, oil droplet size, and concentration are found to have significant effects on the plate-out behavior. Also, the application conditions for hybrid lubrication systems are discussed to realize effective plate-out control.
