Yoshiharu Anbe

Optimal multivariable looper control for hot strip finishing mill

An optimal multivariable looper control system based on optimal-regular theory has been developed for hot-strip finishing mills. Loopers of the mill are installed between stands and are in many cases driven by motors. The goal of looper control is to maintain product quality at a high level by stabilizing the rolling operation. Stability is achieved by keeping the looper angle and tension applied to the strip at given reference values. Control-system features are outlined. It is shown that the control system can maintain a relatively constant strip tension without operator intervention in the presence of rapid change of hydraulic screw down such as automatic gauge control operation. Data obtained at a commercial plant demonstrates that optimal multivariable looper control is more effective than conventional control or noninteractive control.<<ETX>>

Tension Control of a Hot Strip Mill Finisher

Abstract This paper describes interstand tension control by looper and looper less tension control of a hot strip mill finisher. The looper tension control methods are conventional, non-interactive, LQ (Linear Quadratic), H∞, and ILQ(Inverse Linear Quadratic) control.

Hot strip mill mathematical models and set-up calculation

A hot strip mill setup calculation approach has been developed with particular emphasis on the development of a method of optimizing the load distribution among the stands and on the development of accurate setup models. The calculation system includes mathematical models of temperature and deformation resistance in rolling materials. The setup calculation has been carried out for a New Zealand hot strip mill that consists of a reversing rougher and a four-stand finishing mill. With this configuration, a strip was successfully rolled with a finished thickness of 2 mm and a width of 1250 mm. It is concluded that: (1) an effective algorithm for the redistribution of stand rolling powers when the power exceeds the limit can be achieved using the influence coefficient of strip thickness to power: (2) effective temperature modeling can be achieved using a model that incorporates the insulating effect of the coil box and represents the heat loss in the finishing mill with an effective heat transfer coefficient; and (3) for a finishing mill with a coil box, higher accuracies can be achieved by using the cumulative strain to calculate the strip deformation resistance.<<ETX>>

Automatic Flatness Control of Cold Rolling Mill

One of the subjects of cold rolling is a flatness of the rolled strip. Conventionally, measured strip flatness was approximated by polynomial (2th, 4th, 6th) equation across the entire strip width. This made it difficult to deal with desired loose edge or any desired flatness across the entire strip width. Also conventional flatness control was done for the entire strip width, so if there is a different flatness error among drive side and work side, conventional flatness control can not control properly. We propose independent strip flatness control among drive side and work side, and also automatic flatness control (AFC) system with arbitrary desired strip flatness. Also some applied results to cold mill are shown.

Strip Profile Control System for Aluminium Hot Strip Mill

Abstract This paper discusses the strip profile control that was carried out at an aluminum hot strip mill. Calculation procedures for setting up the actuators for each stand of the 3-stand finishing mill involving the double chock work roll bender, VC backup roll/ and work roll coolant spray pattern, necessary for achieving the target strip profile without adverse effect on flatness are presented here in this paper. The work roll thermal crown model and strip profile model that are used for the above strip profile setup are also explained. The results of applying this control system tc the hot strip mill in the Fukui works of Furukawa Aluminum Co. Ltd. are also shown.