Abstract
	Front end of material, which is rolled in heavy plate mills and roughing of hot strip mill stands often bends upwards or downwards. One reason for this phenomenon which is called turn-up and turn-down is a circumferential speed mismatch between the work rolls. Therefore, the curvature of the rolled stock has been investigated.
	A two-dimensional finite element study has been performed. It is based on the fundamental geometric relations and the interdependencies of the used parameters are documented. Special attention is directed to the kinematical influences of the drive because they play a substantial part for turn-up or turn-down.
	It is well known, that the shape factor as well as the speed mismatch is suitable to describe turn-up and turn-down. However, the initial thickness of the rolling stock has a substantial influence on the bending behaviour. Different circumferential speeds of the upper and lower work roll have been measured. Including these measurements in a numerical simulation, it can be shown that speed mismatch is one cause of warping.
	The shape factor (which depends on the entrance thickness) and the entrance thickness are useful reference values for predicting the bending intensity and direction of the rolled stock.