A non-destructive method for determination of twist angle of an outlet product during rolling of an inlet product into said outlet product, comprising the steps of measuring a rotational inlet speed of the inlet product during said rolling, measuring a rotational outlet speed of the corresponding outlet product during said rolling in order to determine a delta rotation, measuring a longitudinal speed and determining a twist angle from said delta rotation and said longitudinal outlet and/or inlet speed.

A first steel strip and a second steel strip (7) are rolled in succession in at least one roll stand (1) of a cold rolling mill. A rolling pause, in which no steel strip is rolled, is provided between the rolling of the first and the second steel strip (7). The first steel strip s fed over a first path starting from a first pay-off reel (2), and the second steel strip (7) is fed over a second path starting from the first pay-off reel (2), or from a second pay-off reel different from the first pay-off reel (2). The first steel strip is not heated as it is fed to the rolling mill (1), whereas, by contrast, the second steel strip (7) is heated. The second path is longer than the first path.

A first steel strip and a second steel strip (7) are rolled in succession in at least one roll stand (1) of a cold rolling mill. A rolling pause, in which no steel strip is rolled, is provided between the rolling of the first and the second steel strip (7). The first steel strip is fed over a first path starting from a first pay-off reel (2), and the second steel strip (7) is fed over a second path starting from the first pay-off reel (2), or from a second pay-off reel different from the first pay-off reel (2). The first steel strip is not heated as it is fed to the rolling mill (1), whereas, by contrast, the second steel strip (7) is heated. The second path is longer than the first path.

When the strip head (7) of a metal strip (1) runs out of a roll stand (2a), a lateral position (y) of the strip head (7) is detected by a detection device (8) at at least one location (P) lying between the roll stand (2a) and a device (8) arranged downstream of the roll stand. A strip position controller (10) is designed as a model predictive controller which ascertains a sequence of adjusting commands (u.sub.k) to be output one after the other in a work cycle (T) on the basis of the detected lateral position (y) of the strip head (7), and the sequence is used to adjust a respective roll gap wedge. The number of control commands (u.sub.k) define a prediction horizon (PH) of the strip position controller (10) in connection with the work cycle (T). The strip position controller (10) at least supplies the roll stand (2a) with the control command (u.sub.0) ascertained to be output next.

To suppress the shape defect at a bite end part of a material to be rolled at a bending rolling stage of a rough rolling step to achieve improvements in productivity such as an improvement in yields and a decrease in crop in production of a steel sheet pile. A production method for producing a steel sheet pile by reducing a raw material in a rectangular cross-section, includes a rough rolling step, an intermediate rolling step, and a finish rolling step, wherein a rolling mill configured to perform the rough rolling step is provided with a caliber configured to perform bending rolling of extending a thickness center line length of the raw material and rolling and shaping the raw material from a rectangular cross-sectional shape to a substantially steel sheet pile cross-sectional shape, and wherein in the bending rolling, rolling that a reduction amount with respect to a predetermined section of a bite end part of the raw material is smaller than a reduction amount with respect to a part other than the predetermined section is performed.

To suppress the shape defect at a bite end part of a material to be rolled at a bending rolling stage of a rough rolling step to achieve improvements in productivity such as an improvement in yields and a decrease in crop in production of a steel sheet pile. A production method for producing a steel sheet pile by reducing a raw material in a rectangular cross-section, includes a rough rolling step, an intermediate rolling step, and a finish rolling step, wherein a rolling mill configured to perform the rough rolling step is provided with a caliber configured to perform bending rolling of extending a thickness center line length of the raw material and rolling and shaping the raw material from a rectangular cross-sectional shape to a substantially steel sheet pile cross-sectional shape, and wherein in the bending rolling, rolling that a reduction amount with respect to a predetermined section of a bite end part of the raw material is smaller than a reduction amount with respect to a part other than the predetermined section is performed.

When the strip head (7) of a metal strip (1) runs out of a roll stand (2a), a lateral position (y) of the strip head (7) is detected by a detection device (8) at at least one location (P) lying between the roll stand (2a) and a device (8) arranged downstream of the roll stand. A strip position controller (10) is designed as a model predictive controller which ascertains a sequence of adjusting commands (u.sub.k) to be output one after the other in a work cycle (T) on the basis of the detected lateral position (y) of the strip head (7), and the sequence is used to adjust a respective roll gap wedge. The number of control commands (u.sub.k) define a prediction horizon (PH) of the strip position controller (10) in connection with the work cycle (T). The strip position controller (10) at least supplies the roll stand (2a) with the control command (u.sub.0) ascertained to be output next.

A Steckel mill has a reversing unit for rolling a rolled product and winding furnaces arranged on the entrance side and exit side of the reversing unit. When rolling the rolled product in a region of a head of the rolled product, a target thickness of the rolled product is ignored, while measuring a current thickness and/or a hardness of the rolled product and comparing this with a setpoint value. One the measured variable reaches or is below the setpoint value, the reversing unit is operated with a view to achieving the target thickness of the rolled product. The Steckel mill is operated to allow for rolling of a cold, non-rollable piece of the rolled product, so that malfunctions are avoided and the usable part of the rolled product is as large as possible.