A new kinematic approach for process set-up and ring evolution prediction in RARR Process

Within Radial Axial Ring Rolling process, a new methodology has been developed in order to minimize the amount of required FE simulations to reach the final set of optimal parameters for the set-up of the process. Through a kinematic approach, a mathematic model has been developed with the aim of predicting the evolution of ring expansion. Based on volume constancy principle, Keeton’s correlation and assuming an initial value for the inner diameter of the blank, which minimizes the scrapped material, the proposed algorithm allows also to determinate blank initial geometry. Optimal ranges for mandrel and axial rolls motion laws are calculated for both speeds in order to reach the final desired geometry of the ring, respecting the conditions that ensure process stability and ring uniform expansion. Moreover, mandrel feeding speed is assumed to be linear and upper axial roll feeding speed is accordingly derived through Keeton’s correlation which ensures process stability. Ring geometry is estimated for each ring portion (slice) and not in terms of average value for the considered round. The mathematical model has been tested through FE simulations applied to three different ring shapes resulting in a reasonable error (<1%) between FE simulations and model estimations, confirming the reliability of the proposed approach.