Patent ID: 8573015

Claim:
A rolling mill that rolls a plate material using vertical work rolls, the rolling mill comprising: a coolant jet spray unit that includes a plurality of nozzles arranged at predetermined intervals in a direction of a rotation axis of the work rolls, and that sprays jets of coolant from the respective nozzles onto the work rolls; a roll temperature estimation unit that estimates a mean temperature of the work rolls; a coolant temperature detection unit that detects a temperature of the coolant; a shape detection unit that detects a shape in a width direction of the rolled plate material; a shape deviation calculation unit that calculates an amount of deviation between a plate material shape detected by the shape detection unit and a target shape; and a shape control unit that controls the shape of the plate material by controlling at least one of a spray quantity and a temperature of the coolant sprayed from the coolant jet spray unit based on a difference between the mean temperature of the work rolls and the temperature of the coolant, and on the amount of deviation between the plate material shape and the target shape, wherein the shape control unit is capable of performing a first control mode to control at least one of the spray quantity and the temperature of the coolant so that the coolant cools the work rolls when the detected temperature of the coolant is lower than the mean temperature of the work rolls, and a second control mode to control at least one of the spray quantity and the temperature of the coolant so that the coolant heats the work rolls when the detected temperature of the coolant is higher than the mean temperature of the work rolls, and the shape control unit is configured to perform one of the first and second control modes depending on a result of comparison of the detected temperature of the coolant and the mean temperature of the work rolls.