Experimental and theoretical studies of workpiece deformation, stress, and strain during flat rolling

Abstract

A review of experimental and theoretical studies of the flat rolling process is presented. An ‘applied mechanics’ view of the rolling process is adopted to study metal flow, pressure, stress, and deformation of the workpiece and the resulting interface distributions of pressure and friction coefficient. The survey focuses largely on cold rolling, though some comments are relevant to hot rolling. Work on rolling equipment, process control, and material behaviour of thin strips, such as in foil production is not considered. The first part of the survey considers experimental work and comments on the various techniques adopted to study metal flow pressure, stress, and strain distributions in rolling. These include caustic, photoelastic, visioplastic, and pressure pin techniques. The discussion of theoretical analyses begins with plane strain models and includes comments on homogeneous and inhomogeneous theories of deformation, the slip line field and upper bound methods, and also on numerical techniques such as the finite element method. The survey of theoretical methods continues with a review of the most recent finite element studies of three-dimensional deformation in rolling. These have been shown to provide great detail of flow patterns, stress and strain distributions, and the pressure distribution at the roll/workpiece interface. Attempts to incorporate the effects of roll deformation, often ignored in theoretical treatments, are also included.