Flatness defects in thin strip cold rolling and the friction impact on it

Abstract : Flatness defects are one of the major problems in strip rolling. They are manifested by a wavy shape on the edge, in the centre or in between. Waves are most of the time transverse, but all directions can be observed. These defects come from the heterogeneity of the stress field and the resulting buckling of the compressive areas out of the roll bite. This paper is based on the approach proposed by [1-3] and [4], and programmed previously [5-7] in the FEM software LAM3/TEC3 [8]. In the present paper, the latter is enhanced and applied to the impact of friction and strip tension on flatness of a rolled thin strip. The study shows e.g. that the optimal setting of Work Roll Bending force (WRB) should be changed when friction varies.