Methodology for calculating the flatness of cold-rolled steel strips

A known cause of flat shape defects in finished cold-rolled steel strips is the inequality of the drawing ratios across the strip width. Difference in the values ​​of these ratios is affected by the roll barrel profiling parameters, energy-power parameters of rolling, operating parameters of the automatic profile and strip shape control system. The impact of all technological factors on the strip shape is complex. The paper considers an approach that takes into account the main operating parameters of rolling equipment allowing to estimate the type and amplitude of flatness defects in finished steel strips. When implementing this approach, 6 calculation stages were performed: energy-power calculation of the cold rolling process; calculation of elastic deformations of the working roll barrel surface; assessment of wear of the working roll barrel surface; calculation of the roll thermal profile; assessment of convexity of the steel strip transverse profile; assessment of flatness indicators of the finished strip. To calculate the parameters affecting the flatness of the rolled product, known calculation methods adapted to specific process conditions were used. The results of assessing the shape indicators of the rolled strip obtained using the model were compared with the results of modeling in the Deform 3D program. The modeling results demonstrated reliability of the proposed approach to assessing the rolled product quality.