Rolling mill and rolling method

A rolling mill comprising:

• upper and lower work rolls as a pair configured to roll a rolling material;
• upper and lower intermediate rolls as a pair supporting the paired upper and lower work rolls from above and below, respectively, and being supported movably in a roll axial direction, the paired upper and lower intermediate rolls including tapering sections at end portions of the paired upper and lower intermediate rolls that are point-symmetric about a center of the rolling material in a strip width direction thereof;
• upper and lower back-up rolls as a pair supporting the paired upper and lower intermediate rolls from above and below, respectively;
• position adjusting means for adjusting positions of the paired upper and lower intermediate rolls relative to the paired upper and lower work rolls and the paired upper and lower back-up rolls in a direction of conveyance of the rolling material;
• detecting means for detecting horizontal forces on the work rolls;
• offset-amount calculating means for calculating offset amounts of the intermediate rolls based on the horizontal forces on the work rolls detected by the detecting means;
• and
• controlling means for controlling the position adjusting means such that the positions of the intermediate rolls are offset by the offset amounts calculated by the offset-amount calculating means, wherein
• the detecting means includes load measuring means provided to bearing chocks of the intermediate rolls for measuring horizontal loads on the intermediate rolls, and
• the offset-amount calculating means calculates the horizontal forces on the work rolls based on the horizontal loads on the intermediate rolls measured by the load measuring means.

A rolling method using a rolling mill including

• upper and lower work rolls as a pair configured to roll a rolling material,
• upper and lower intermediate rolls as a pair supporting the paired upper and lower work rolls from above and below, respectively, and being supported movably in a roll axial direction, the paired upper and lower intermediate rolls including tapering sections at end portions of the paired upper and lower intermediate rolls that are point-symmetric about a center of the rolling material in a strip width direction thereof,
• upper and lower back-up rolls as a pair supporting the paired upper and lower intermediate rolls from above and below, respectively, and
• position adjusting means for adjusting positions of the paired upper and lower intermediate rolls relative to the paired upper and lower work rolls and the paired upper and lower back-up rolls in a direction of conveyance of the rolling material,
• the position adjusting means including offset cylinders provided to bearing chocks of the intermediate rolls,
• the rolling method comprising:
• measuring pressures in the offset cylinders,
• calculating horizontal forces on the paired upper and lower work rolls based on the measured pressures obtained in the measuring step;
• calculating offset amounts of the intermediate rolls based on the calculated horizontal forces on the work rolls;
• and
• controlling the position adjusting means such that the positions of the intermediate rolls are offset by the calculated offset amounts.