Advanced roll bite models for cold and temper rolling processes

This paper describes on-going efforts made to develop a fast and robust roll bite model for cold and temper rollingprocesses including a non-circular roll profile and a mixed lubrication model based on lubricant flow and surfaceasperity deformation models (only Coulomb friction is used in this paper however). First, the existing roll bitemodels are reviewed in details to understand their physics, their specificities, their differences and their resolutionstrategies, with a particular focus on strategies allowing for short computing time (CPU) even for heavily deformednon circular roll profiles. From this preliminary analysis, some existing strategies are selected to develop a newroll bite model. It includes in particular calculation of roll surface circumferential displacements for roll profiledetermination and an efficient relaxation technique that updates the relaxation factor dynamically at each rollstripcoupling iteration. The resulting computing time is generally less than one second (on a single processor)and convergence has been obtained for all types of cold and temper rolling conditions, from tandem mill heavyreductions to double reduction of very thin strips and to very light reduction temper rolling (< 0.5%). Simulationresults are also discussed against finite element (FE) results. Finally, it is illustrated how this new roll bite modelcan be used on an industrial database to develop accurate presets of roll force for temper mills