Strip lateral position control using electromagnets in continuous processing line

Abstract

In continuous metal strip processing lines, such as pickling, annealing and surface treatment lines, lateral instability of strips is a common problem. Strip lateral movement has a bad influence on productivity of the processing lines. A simple and effective device to control a lateral position of a strip is required because conventional preventions such as a steering roll and crown roll are not effective. In this study, a method of controlling a strip lateral position using electromagnets was investigated. First, theoretical equations were derived to predict capability to control a strip. Next, the derived theory was verified compared with lab experiments. The results obtained can be summarized as follows: (1) The theoretical equations of velocity of lateral movement are derived from inclination when the strip is attracted by electromagnet(s). The inclination is calculable from geometric relation. (2) It is found that the theoretical equations are valid by lab experiments in the conditions of changing attracting displacement and line speed. Controlling lateral movement using electromagnets is possible, and the control capability can be estimated by the derived theory. (3) The velocity of lateral movement in the case of attracting the half of strip width is three times as fast in the case of attracting the edge of the strip.