Investigations on Formation of Shape Defects in Square Rolling of Uniform Thin Flat Sheet Product

Abstract

In rolling of wide strip, longitudinal compressive stresses develop as a result of non-uniform deformation along the plate width, which enhance long-shape wave. Different reduction as a result of uneven geometrical factor along the plate width considered as a main cause of such non-uniform deformation in flat rolling. In order to investigate the non-uniformity of deformation that take place in width direction as a cause of non-geometrical factors, a 3D model of flat rolling process employing ABAQUS software, which includes the buckling features is created. It is realized that in addition to uneven geometrical factor which influence the plate quality, the variation of forming condition along the width as a result of different boundary condition also lead to heterogeneity of the material flow in the roll gap and cause to non-uniform distribution of longitudinal stress. In addition to non-uniform flow of material along the plate width, different transversal flow of material along the plate edge in the roll gap will change the distribution of longitudinal stress after rolling. Despite the fact that variation in residual stresses is calculated to be very low but it is shown that even low values of the residual stresses plays an important role in buckling of thin flat rolled products.