Development of an innovative Force - Torque Model to Predict the SkinPass Rolling Forces on AHSS

摘要

On cold mills the reduction is usually high and models which utilize approximations for some parameters like roll deformation andelastic behavior of the strip are enough accurate to predict rolling forces and torques.On skin pass mills the magnitude of the plastic deformation in the strip is very small and it may be in the same order than the elasticdeformation of the strip at the entry and exit of the roll gap. This is especially true for High Strength Steels. Therefore, the new modelshave to compute the true roll deformation and not accept the simple Hitchcock approach. Similarly, the entry and exit elasticdeformation of the strip and a variation of the friction coefficient in the gap must be included.To take into account the big interaction between the rolling stresses and the roll deformations inside the gap, CMI has developed amodel using a combination of analytic formulas for plastic and elastic deformations of the strip and finite element computations forroll deformations. To be friendly usable by designers this model is developed under excel file.Industrial data referring to Gi sheets up to DP800 and Skinpassed in Wet conditions have been used to calibrate and validate theresults. Therefore, the model is being used to predict the Skin pass parameters for DP1200. The next step will consist in the validationof the predictions.