Hot Rolling Modelling: Optimization of Trimmed Area Based on Crocodiling and Edge Cracking Simulations

Hot rolling on a reversing mill is the first stage of the transformation route for producing aluminium plates and coils. Optimizing the recovery and reducing cracks occurrences are major objectives of our operational excellence program. Among the six faces of a plate, two of them are constrained by the rolls and the others are trimmed at the end. The understanding of the deformation of these free edges is required prior to any metal loss optimization. For this purpose, two FEM models were developed to assess final shape and strain field. A steady-state 3D approach is used to evaluate the effects of rolling parameters, including the use of vertical rolls, on the edge deformation. Concerning the ends, a 2D plane-strain modelling is chosen to be able to predict the ‘crocodiling effect’ and study the impact of initial shape and rolling parameters. In both models, a remeshing procedure had to be implemented in order to follow the high level of deformation that takes place during this multi-pass process. In combination with the tracking of the surface deformation and in order to address the issue of edge cracking, a Hosford-Coulomb empirical damage model is implemented and validated with lab trials.