Rolling mill and method of controlling the same

Abstract

A rolling mill includes a roll pair, having first and second rolls, for rolling a bar steel, and first and second hydraulic cylinders for moving the first roll relative to the second roll, the first and second hydraulic cylinders being respectively connected to first and second supporting portions rotatably supporting the first roll at both ends thereof. A rolling area for rolling the bar steel, which is set as a partial continuous area in the longitudinal direction of the roll pair, is positioned so that distances from the rolling area to the supporting portions differ from each other, and the rolling mill includes: a distance sensor to measure a roll deflection in the rolling area of at least one of the rolls; and a controller to control the amount of depression of the hydraulic cylinders based on a detection value of the distance sensor.

1 . A rolling mill that includes a roll pair, having a first roll and a second roll, for rolling a bar steel to be rolled, and a first hydraulic press cylinder and a second hydraulic press cylinder for moving the first roll relative to the second roll, the first hydraulic press cylinder and the second hydraulic press cylinder being respectively connected to a first supporting portion and a second supporting portion that rotatably support the first roll at both ends of the first roll, wherein
 a rolling area for rolling the bar steel, which is set as a partial continuous area in a longitudinal direction of the roll pair, is positioned so that a distance between the first supporting portion and the rolling area and a distance between the second supporting portion and the rolling area differ from each other, and   the rolling mill further comprises:   a distance sensor configured to measure a roll deflection in the rolling area of at least one of the first roll and the second roll; and   a controller configured to control an amount of depression of the first hydraulic press cylinder and an amount of depression of the second hydraulic press cylinder based on a detection value of the distance sensor.   
     
     
         2 . The rolling mill according to  claim 1 , wherein
 a plurality of the rolling areas are set at different positions in the longitudinal direction of the roll pair.   
     
     
         3 . The rolling mill according to  claim 2 , wherein
 at least one distance sensor is provided for each of the plurality of rolling areas set at the different positions.   
     
     
         4 . The rolling mill according to  claim 1 , further comprising a movably-supporting device that supports the distance sensor movably in the longitudinal direction. 
     
     
         5 . The rolling mill according to  claim 4 , wherein
 the movably-supporting device includes: a mounting portion, to which the distance sensor is fixed; a rail portion, with which the mounting portion slidably engages; and a driving device for moving the mounting portion along the rail portion.   
     
     
         6 . The rolling mill according to  claim 1 , wherein
 the rolling mill is configured to be able to measure the roll deflections in both end portions of the rolling area in the longitudinal direction.   
     
     
         7 . The rolling mill according to  claim 1 , wherein
 the controller is configured to control the amount of depression of the first hydraulic press cylinder and the amount of depression of the second hydraulic press cylinder in real time while the bar steel is rolled.   
     
     
         8 . The rolling mill according to  claim 1 , wherein
 each of the first roll and the second roll is provided with a caliber in the rolling area.   
     
     
         9 . A method of controlling a rolling mill that includes a roll pair, having a first roll and a second roll, for rolling a bar steel to be rolled, and a first hydraulic press cylinder and a second hydraulic press cylinder for moving the first roll relative to the second roll, the first hydraulic press cylinder and the second hydraulic press cylinder being respectively connected to a first supporting portion and a second supporting portion that rotatably support the first roll at both ends of the first roll, the method comprising:
 positioning a rolling area for rolling the bar steel, which is set as a partial continuous area in a longitudinal direction of the roll pair, so that a distance between the first supporting portion and the rolling area and a distance between the second supporting portion and the rolling area differ from each other;   measuring a roll deflection in the rolling area of at least one of the first roll and the second roll; and   controlling an amount of depression of the first hydraulic press cylinder and an amount of depression of the second hydraulic press cylinder based on the roll deflection.