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.

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 method for the stepped rolling of a metal strip unwinds the metal strip by a feed reel device and winds-up the metal strip by a winding reel device. The metal strip is guided through a roller gap formed between two working rollers during the rolling process, and the roller gap is changed in a controlled manner during the rolling process, whereby a thickness of the metal strip is changed in steps in the longitudinal direction during the rolling process. Tension applied to the metal strip is controlled such that the rolling force applied to the metal strip by the working rollers is constant during the rolling process.

Regarding each rolling mill, a rolling torque Gi before biting into a downstream stand is stored, the peripheral velocity of a most downstream stand Rn is controlled to be Gn1=Gn1* after biting into Rn, and a rolling torque Gn** of Rn after tension is stabilized is stored. After that, the peripheral velocity of a rolling mill Ri is controlled to be Gi=Gi* toward an upstream side, and the peripheral velocity of a rolling mill Rk at a downstream side of the rolling mill Ri is controlled to keep Gk=Gk** (k=i+1 to n) so that a rolling torque of a most upstream rolling mill R1 becomes equal to a stored G1*. Stabilization of material passage and improvement in accuracy of a product dimension are enabled by controlling tension between stands with high accuracy by using a simple control system without using table values or the like by each rolling condition even under a condition where a distance between stands is short.

A roll feeder is usable to intermittently feed a coiled material. The roll feeder includes a paired first roll and second roll, a meandering detector, a pressing component, and a controller. The paired first roll and second roll are disposed so as to clamp the coiled material. The paired first roll and second roll are configured to feed the coiled material in a conveyance direction. The meandering detector is configured to detect meandering of the coiled material from a specific conveyance position in a width direction perpendicular to the conveyance direction of the coiled material. The pressing component is configured to press the first roll against the coiled material being conveyed. The controller is configured to control the pressing component so as to correct the meandering based on detection by the meandering detector.

A semi-automatic adjustment device for suppressing tension fluctuations during a rolling process of an ultra-thin strip includes a semi-automatic tension regulator, a semi-automatic tuned mass damper of variable stiffness and damping, a coiler, a tension roller and a twenty-high roller system. The semi-automatic tension regulator is disposed between the coiler and the tension roller, the semi-automatic tuned mass damper of variable stiffness and damping is disposed between the tension roller and the twenty-high roller system. The semi-automatic adjustment device can be used to reduce a short-time fluctuation impact of tension during startup and shutdown of a twenty-high roll mill when the twenty-high rolling mill rolls an ultra-thin strip, improve system stability, absorb the continuous micro disturbances generated during the rolling process of the twenty-high roll mill, and achieve flexible and stable adjustment of tension during the rolling process.

A roll feeder is usable to intermittently feed a coiled material. The roll feeder includes a paired first roll and second roll, a meandering detector, a pressing component, and a controller. The paired first roll and second roll are disposed so as to clamp the coiled material. The paired first roll and second roll are configured to feed the coiled material in a conveyance direction. The meandering detector is configured to detect meandering of the coiled material from a specific conveyance position in a width direction perpendicular to the conveyance direction of the coiled material. The pressing component is configured to press the first roll against the coiled material being conveyed. The controller is configured to control the pressing component so as to correct the meandering based on detection by the meandering detector.

A method for the stepped rolling of a metal strip unwinds the metal strip by a feed reel device and winds-up the metal strip by a winding reel device. The metal strip is guided through a roller gap formed between two working rollers during the rolling process, and the roller gap is changed in a controlled manner during the rolling process, whereby a thickness of the metal strip is changed in steps in the longitudinal direction during the rolling process. Tension applied to the metal strip is controlled such that the rolling force applied to the metal strip by the working rollers is constant during the rolling process.