A Holistic Modeling Approach for the Design of Tension Leveling and Scale Breaking Processes and Equipment

摘要

Tension leveling is employed as one of the final processes in continuous galvanizing and finishing lines in order to improve strip flatness and minimize residual stresses. Scale breaking is normally located at the entry of continuous pickling lines to break the scale layer on the hot strip surface and to improve strip flatness. In both applications, the strip is bent under high tension around multiple rolls with small diameters whereby small elasto-plastic strains are induced, leading to plastic dissipation and significant tension losses at the typically undriven process rolls. To improve the process design as well as the equipment layout of tension levelers, precise simulation models are essential. Extensive analyses of the tension leveling process (employing commercial FEM-packages) have led to a comprehensive understanding of the underlying physical effects and correlations. In order to reduce the extensive computational costs of FEM models (while assuring high significance of results), an alternative and new modelling approach based on the principle of virtual work and parametric shape functions (PSF) for curvature and strain distributions was employed. Compared to optimized (Lagrangian) FEM models, the new tailor-made PSF model (based on a specific Arbitrary Lagrangian-Eulerian formalism) allows a drastic reduction of degrees of freedom and computational costs, while the key process results (e.g. tension level and tension loss, strip bending line, plastification, global strain level, etc.) show high agreement with those obtained from FEM-models. Following a holistic, mechatronic modeling strategy, these process results can be easily transferred to a generic model for the analysis of various drive concepts.