Design and function of CVC rolls as a flatness actuator in a cold rolling mill

Abstract: When cold rolling thin steel strips with high tensile strength, reversible cluster mills are used. The customer’s demands are high on the products flatness, which is controlled by the different flatness actuators that the mill is equipped with. The objective of this thesis was to find an optimal CVC shape on the shifting inner second intermediate roll in the 20-high cluster mill KV96 at Sandvik Materials Technology in Sandviken. The project consisted of a theoretical calculation of the roll shape that can give the desired change of the strips flatness and practical development and testing of these rolls in the mill. The results showed that the flatness of the strips can be altered with up to 30 I-units at the edges and 20 I-units in the center with the use of an inner second intermediate roll of the CVC type as this study has concluded. In this work, three CVC shapes was developed using the calculation software Cluster. The rolls was then ground and verified in the mill.