Integrated analysis of transfer bar profile evolution and its impact on final strip profile: a Lagrangian rolling approach with plant validation

In hot strip rolling, even moderate variations in transfer bar (TB) thickness can critically affect the final strip profile and surface quality. This study investigates the influence of roll wear in the last roughing stand (R5) on these inconsistencies by integrating plant measurements with finite element method (FEM) simulation. Work roll profiles were captured at different stages of a rolling campaign using a Pessometer. These profiles were precisely reconstructed using CAD software and incorporated into the FEM based DEFORM-3D simulation environment to reflect worn roll geometries within a thermo-mechanical framework. A comprehensive FEM model was developed to emulate real mill conditions; from slab discharge at the reheating furnace to deformation through the roughing stands and up to the third finishing stand, where the strip's geometric integrity, especially profile is predominantly established. Simulations conducted with varying degrees of R5 roll wear revealed that roll surface degradation induces non-uniform thickness distribution in the TB. These inconsistencies persist into the finishing mill and lead to shape-related defects such as ridge formation. This integrated approach not only helps to visualise the genesis of shape defect but also provides actionable insights into optimal roll maintenance schedules and control interventions to ensure more uniform strip production.