Development of a Novel Analytical Framework for Investigating Non-symmetric Deformation Behavior in Strip Rolling

Abstract

In recent years, the asymmetrical rolling process has attracted considerable research attention due to its ability to induce non-uniform deformation characteristics within metallic workpieces. In this context, the present study introduces a novel analytical framework for asymmetrical cold rolling based on an enhanced slab method, specifically designed to overcome the inherent limitations of existing analytical models when applied to a wide range of asymmetric rolling conditions. A newly developed mathematical formulation for the asymmetric slab rolling process is proposed, offering a more comprehensive representation of the deformation mechanics. Unlike conventional approaches, the modified model identifies the emergence of three distinct deformation regions within the roll bite: the backward slip zone (BSZ), the forward slip zone (FSZ), and a newly characterized cross-shear zone (CSZ). This zonal classification provides deeper insight into the complex material flow behavior unique to asymmetric rolling. The study systematically investigates the influence of critical rolling parameters—including thickness reduction, roll speed ratio, applied tensions, and friction coefficient—on the configuration and evolution of these deformation zones. It is demonstrated that at specific critical roll speed ratios and tension levels, distinct deformation zone configurations are established, validating the adaptability of the proposed model under varying process conditions. Furthermore, the interdependence between deformation zone configurations and rolling parameters is elucidated through comprehensive process maps, which illustrate the variation of critical speed ratios and critical tensions across diverse rolling scenarios. To quantify the relative influence of process variables, Grey Relational Analysis (GRA) is employed, revealing that the roll velocity ratio is the most dominant factor governing rolling responses, contributing 80% to overall performance optimization. The front tension emerges as the second most influential parameter, accounting for 8.64%, and plays a supportive role in enhancing process stability and surface integrity. The analytical predictions of the proposed model are rigorously validated through confirmation experiments, demonstrating strong agreement with theoretical outcomes. Based on the GRA-derived optimal parameter set, the study recommends specific operating conditions that effectively minimize roller surface damage while simultaneously improving the surface quality of the rolled product