Controlling the Electric Drives of a Rolling Mill Stand Using the Metal Weight Consistency Criterion

Abstract

It is crucial to limit the force link between the vertical and horizontal stands of a plate rolling mill implemented through the metal workpiece. Such rolling mills are often used for the formation of conical profiles at the ends of workpieces by moving the rollers during the rolling process. This results in the changing of instantaneous metal volumes at the vertical stand output and horizontal stand input and the formation of tensions or workpiece damming. In well-known control systems, electric drive speeds for these stands is based on the requirement of constant instantaneous metal volumes in inter-stand gaps. When automated roller gap adjustment is used during rolling, this condition is not fulfilled. The authors justify the adjustment principle for the electric drive speeds of consecutive stands based on the constant metal weight criterion. The authors developed a control method for the electric drive speed of the vertical stand in proportion to the changing of the gap during screwdown movements. This article presents the results of simulation modeling confirming the compensation of tension deviation during the changing of the roller speed ratio for the horizontal and vertical stand. The method developed is deemed effective. The authors provided some recommendations on its introduction.