An investigative study on the performance of twist roll machine in a continuous cold strip rolling mill

In many modern continuous production lines of steel sheets, a twist roll machine is used to change the strip direction for shortening the production line. A twist roll machine typically consists of a cylindrical body on which some guide rollers are mounted in rows to gradually change the traveling direction of the strip when passes over the guide rollers. In this article, quality of the sheets after exiting an industrial twist roll machine is first investigated. The amount and distribution of wear on the guide rollers are also assessed by measuring and comparing diameter at different sections of selected worn and new guide rollers. The specific wear rate as well as friction coefficient for guide rollers made of two different popular polymers is measured by pin-on-disk wear tests. Details of the strip path on the twist roll machine as well as contact between the strip and all the guide rollers are specified, and stress distribution in strip and the guide rollers is studied by finite element analysis. Effects of the guide rollers material and arrangement, the bridle rolls tension, and width and thickness of the strip on the amount and distribution of wear on the guide rollers as well as the elasto-plastic response of the strip are studied. The results are utilized to propose techniques for reducing defects on the sheet and the guide rollers, and finite element simulations show the effectiveness of these techniques.