A device and a method for rolling a metal strip. A distance of the upper/lower backup roll at at least one point thereof from a predetermined upper/lower reference point is measured by an upper/lower sensor and the measured values of the sensors are sent to a control device. A strain of the roll stand is calculated using a mathematical model, taking into account the rolling force generated. By the control device, an absolute value of the roll gap and thus the resulting thickness of the rolling stock is determined by the control device on the basis of the measured positions of the backup rolls and the calculated strain of the roll stand.

One aspect of the invention concerns a metallic bar or post (15) comprising a longitudinal axis; a spine (16) extending along the longitudinal axis; and at least three interconnected arms (17-19), each of which extends along the spine (16) and generally radially from the spine (16), with a free end (20-22) of each said arm (17-19) being tapered in the direction of the free end (20-22) to the spine (16). Other aspects of the invention concern a roll stand and rolling mill for forming the bar or post (15).

One aspect of the invention concerns a metallic bar or post (15) comprising a longitudinal axis; a spine (16) extending along the longitudinal axis; and at least three interconnected arms (17-19), each of which extends along the spine (16) and generally radially from the spine (16), with a free end (20-22) of each said arm (17-19) being tapered in the direction of the free end (20-22) to the spine (16). Other aspects of the invention concern a roll stand and rolling mill for forming the bar or post (15).

A device and a method for rolling a metal strip. A distance of the upper/lower backup roll at at least one point thereof from a predetermined upper/lower reference point is measured by an upper/lower sensor and the measured values of the sensors are sent to a control device. A strain of the roll stand is calculated using a mathematical model, taking into account the rolling force generated. By the control device, an absolute value of the roll gap and thus the resulting thickness of the rolling stock is determined by the control device on the basis of the measured positions of the backup rolls and the calculated strain of the roll stand.

A device and a method for rolling a metal strip. A distance of the upper/lower backup roll at at least one point thereof from a predetermined upper/lower reference point is measured by an upper/lower sensor and the measured values of the sensors are sent to a control device. A strain of the roll stand is calculated using a mathematical model, taking into account the rolling force generated. By the control device, an absolute value of the roll gap and thus the resulting thickness of the rolling stock is determined by the control device on the basis of the measured positions of the backup rolls and the calculated strain of the roll stand.

A thickness controlling method for a rolling mill includes using a regression model to recursively approximate a relationship between the roll force change amount between the preceding material and the present material and a gap error change amount of the rolling mill, and predicting a gap error in a rolling of the present material on the basis of the regression model, the preceding material being a rolled coil rolled by the rolling mill immediately prior, and the present material being another rolled coil to be rolled following the preceding material, correcting a gap setting amount in the rolling of the present material, on a basis of a value of the predicted gap error, and updating a regression coefficient of the regression model, on a basis of an actual roll force and an actual gap error change amount obtained from the rolling of the present material.

A thickness controlling method for a rolling mill includes using a regression model to recursively approximate a relationship between the roll force change amount between the preceding material and the present material and a gap error change amount of the rolling mill, and predicting a gap error in a rolling of the present material on the basis of the regression model, the preceding material being a rolled coil rolled by the rolling mill immediately prior, and the present material being another rolled coil to be rolled following the preceding material, correcting a gap setting amount in the rolling of the present material, on a basis of a value of the predicted gap error, and updating a regression coefficient of the regression model, on a basis of an actual roll force and an actual gap error change amount obtained from the rolling of the present material.