Influences of thermal crown and wear crown of work roll on strip shape in tandem cold rolling using a novel 3D multi-pass FE model

Thermal crown and wear crown of work roll (TWW) are the main interfering factors of loaded roll gap profile in tandem cold rolling (TCR). However, the effect of TWW on the strip shape is not well understood. This paper presents a quantitative study about the effect of TWW on the strip crown and strip flatness based on a novel 3D multi-pass elastic-plastic finite element (EPFE) model that has been validated by industrial trials in the TCR. The results show that the thermal crown introduces the centre wave and quarter wave, while the wear crown brings in the edge wave and edge-centre coupled wave; the thermal crown has a larger influence efficiency on the quadratic strip shape than the wear crown does, while the wear crown exerts a larger influence efficiency on the quartic strip shape than the thermal crown does. In addition, the influence efficiency of TWW on the strip crown decreases nonlinearly with an increase in strip plastic rigidity from Pass 1 (P1) to Pass 5 (P5). This is the first scientific report on the link between the strip plastic rigidity and the effect of TWW on the strip crown, affording the mathematical models for predicting the influence efficiency of TWW based on the strip plastic rigidity at each pass.