Advanced roll bite models for cold and temper rolling processes
Résumé
This paper describes on-going efforts made to develop a fast and robust roll bite model for cold and temper rolling processes includinga non-circular roll profileand a mixed lubrication model based on lubricant flow and surface asperity deformation models (only Coulomb friction is used in this paperhowever). First, the existing roll bite models are reviewed in details to understand their physics, their specificities, their differences and their resolution strategies, with a particular focus on strategies allowing for short computing time (CPU) even for heavily deformed non circular roll profiles. From this preliminary analysis, some existing strategies are selected to develop a new roll bite model. It includes in particular calculation of roll surface circumferential displacements for roll profile determination and an efficient relaxation technique that updates the relaxation factor dynamically at each roll-strip coupling 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 heavy reductions to double reduction of very thin strips and to very light reduction temper rolling (< 0.5%).Simulation results are also discussed against finite element (FE) results. Finally, it is illustrated how this new roll bite model can be used on an industrial database to develop accurate presets of roll force for temper mills.