Proposal of a new method for the spread rolling of thin strips

It has been believed impossible to increase the width of thin and wide strips continuously by rolling. This paper proposes a new method for the spread rolling of thin and wide strips. The method consists of three-pass rolling operations. In the first pass, the thickness of several portions of the width is reduced between a grooved roll that has many protuberances and a flat roll, whilst the other portions bulge into the roll grooves. In the second pass, the bulged portions are flattened by flat rolls. In the final pass, the strip is again rolled by flat rolls, and widened flat strips are obtained. In order to evaluate the method, several rolling experiments have been conducted with a type of clay (plasticene) as a model material. The influence of the rolling conditions and of the grooved roll profile have been investigated experimentally. It has been found that 100-mm wide and l-mm thick strips can be widened by up to 5 mm for a 90% reduction in thickness. The spreading effect is more obvious in the case of thinner strips. (C) 1999 Elsevier Science S.A. All rights reserved.