A method for operating a roll stand for the stepped rolling of metal strip is described. The metal strip is initially fed into a roll stand on the infeed side, where it is step-rolled. This creates a leading and a trailing section of the metal strip, each with different thicknesses. After the roll stand, the step-rolled metal strip initially passes through an outfeed-side strip accumulator before it is wound into a coil by an upcoiler. The outfeed-side reel is controlled to a constant strip tension. To keep the outfeed-side strip tension sufficiently constant even in the case of rapid changes in the size of the roll gap and the resulting rapid changes in thickness in the rolled metal strip the control of the strip tension with the aid of the upcoiler is supplemented by a position control for a roller unit in the outfeed-side strip accumulator.

An apparatus for controlling a strip tension during flexible rolling of metal strip comprises a roll arrangement with at least one dancer roll, the position of said dancer roll being adjustable for controlling the strip tension of the metal strip, at least one hydraulic drive coupled to the dancer roll for adjusting the dancer roll, a hydraulic tank for hydraulic fluid, which is fluidly connected to the hydraulic drive via a hydraulic supply line, a controllable valve arrangement between the hydraulic tank and the hydraulic drive for controlling the hydraulic drive, a hydraulic pump with which the hydraulic drive is supplied with hydraulic fluid from the hydraulic tank, and at least one hydraulic pressure accumulator for temporarily storing hydraulic fluid previously delivered by the hydraulic pump, the hydraulic pressure accumulator being arranged between the hydraulic pump and the valve arrangement, wherein a pressure sensor is arranged in the hydraulic drive for determining the hydraulic pressure.

A device for laterally guiding a metal strip (1, 13) running over a loop lifter (4, 12) between two roll stands (2, 3, 8, 9) of a finishing train. The device includes at least one main member module (14) extending in a direction between the roll stands. The module has a guiding plane (15), and also supports a number of wear members (18, 19, 20), each with a wear surface (21, 22, 23). Those wear members can be turned to a number of rotational positions. At least two wear members (18, 19, 20) are respectively arranged between one of the roll stands (2, 3, 8, 9) and the loop lifter, wherein, seen in the direction of the loop lifter (4, 12), the surface area of the wear surface (21, 22, 23) of adjacent wear member bodies (18, 19, 20) increases. During the operation of the device, at least one of the wear members is rotated while the metal strip (1, 13) is running to expose another area of the wear surface to the side of the strip.

In a normal operation of a roll stand (e.g. 4) of a roll train, working rolls (10) of the roll stand (4) are adjusted to a roll gap (s4) by adjusting a control element position (p4) of a control element (14) of the roll stand (4), such that the working rolls (10) roll the metal band (5). To determine the control element position (p4) to be adjusted, a calibration value (sC4) of the respective roll stand (4), further status parameters (P4) of the roll stand (4) and a target roll gap (s4*) are specified to a model (15) of the roll stand (4). The model (15) determines the control element position (p4) to be adjusted therefrom. In the calibration operation, a control element position (p4) is initially adjusted such that the metal band (5) passes through the roll stand (4) without being rolled. The control element position (p4) is varied such that the working rolls (10) roll the metal band (5). A thickness (d) of the metal band (5) is detected by a downstream thickness-measuring device (9). The thickness (d), further status parameters (P4) and the control element position (p4) are supplied to the model (15), which determines the calibration value (sC4) of the respective roll stand (4) therefrom. Subsequently, normal operation is resumed and the previously determined calibration value (sC4) is used to determine control element positions (p4) to be adjusted as the calibration value (sC4) of the respective roll stand (4).

Method for the production of flat metal products, in particular coils of strip, in endless and/or semi-endless mode, in which a metal product is continuously fed to a rolling mill consisting overall of at least 4 stands. The rolling stands are, in sequence, roughing stands, and finishing stands. It is provided to perform a flying gauge change of the metal product exiting from the rolling mill.

A deflector roll, which changes a travelling direction of a metal strip being threaded, includes a roll main body that is rotatably supported by a roll frame and a sliding member that is provided on an outer surface of the roll main body. The sliding member is configured to have the metal strip wrapped thereon and to be movable along an axial direction of the roll main body while maintaining that wrapped state.

A steel-sheet snaking preventing device for a vertical looper includes a jack mechanism provided at each of at least two corners of a looper carriage and coupled via a metal fitting to a chain or a wire rope that pulls the looper carriage; a tilt meter configured to detect the amount of tilt of the looper carriage; a level meter configured to detect a height of the looper carriage; and a means for receiving detection signals from the tilt meter and the level meter, determining the amount of tilt of the looper carriage at which the amount of snaking of a steel sheet becomes zero, sending the determined amount of tilt of the looper carriage as a command to the jack mechanism, and controlling the amount of tilt of the looper carriage by the jack mechanism.

A system for maintaining a continuous speed in a long rolling mill is provided that includes a plurality of guide rollers that feed a billet product from a caster to an entry roll stand along a mill pass line to an exit roll stand. Also, the system includes a plurality of gauges positioned at a plurality of locations along the mill pass line, the gauges perform speed measurement of the billet product passing along the guide rollers. Furthermore, the system includes a logic controller that receives the speed measurement and maintains a speed relationship where the speed between the caster and the entry roll stand is constant as well as the exit speed of the end roll stand is also constant.

A method and device for cooling a preliminary strip of metal in a hot rolling mill including work rolls by spraying a cooling agent on to the preliminary strip, screening the preliminary strip in an edge area of the strip from influence of the cooling agent, and deflecting the cooling agent in the area of the strip edges of the preliminary strip, wherein the cooling agent is deflected from the strip edges in an area of an inlet guide of a work a work roll.