EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

Threading is a critical phase in hot rolling both in the finishing and the roughing mill. To avoid threading refusals which cause loss of productivity and steel yield, some constrains are applied on the process: no lubrication or only on the strip body, limitation of thickness reduction, high slab temperature at the furnace exit… However, we had no means to estimate the threading risk for each incoming strip or the needed process modification to be applied to avoid the problem. Therefore, we developed a fast analytical model of the threading phase based on power balance between friction and deformation to predict the strip speed evolution when it enters into the stand. This model has been validated with comparison with finite element simulations in the same conditions and the results between both models are in good agreement. As the computation time for the analytical model is much lower than the finite element simulation, we performed a comprehensive sensitive analysis to study the influent parameters and efficient actuators to decrease the threading refusal risk.