Influence of Dog-Bone Width on End Profile in Plan View Pattern Control Method for Plate Rolling

A plan view pattern control method for plate rolling called Mizushima Automatic Plan View Pattern Control System (MAS) or Dog Bone Rolling (DBR) was developed. In this method, the slab is given a non-uniform thickness profile in the width direction to obtain non-uniform elongation. In order to make the plate more rectangular under various rolling conditions, prediction of elongation is necessary. In this research, the influence of the dog-bone width (overly thick part at the slab width edge) on the fish-tail length (over-elongation at the slab end) is investigated. The fish-tail length increases as the dog-bone width increases in spite of the same dog-bone height. This phenomenon is related to the following behavior of the restriction of excessive elongation of the dog-bone: As the dog-bone width increases, the working length of restricting stress increases. Hence, restricting stress is released earlier and the rolling length for fish-tail formation increases. As a result, the fish-tail length increases. Therefore, for the prediction of plan view pattern, not only the dog-bone thickness, but also the dog-bone width should be considered.