Temperature field prediction and thermal convexity compensation control for hot-rolling work rolls throughout the entire rolling cycle

During continuous rolling, the dynamic changes in the thermal camber of the work roll caused by uneven temperature distribution are a key factor affecting the flatness accuracy of the strip. To achieve stable flatness control, this paper proposes a thermal camber compensation strategy for the work roll based on the prediction of the temperature field over the entire rolling cycle. First, a three-dimensional transient thermo-elastic coupling model is established, taking into account the temperature dependence of material parameters and complex boundary conditions, to achieve high-precision dynamic simulation of the full-cycle temperature field of the work roll from initial heating to quasi-steady state. Based on this, an analytical thermal camber model is derived and integrated with the original roll profile, roll offset, and roll bending processes to construct a complete predictive model of the transfer chain from the temperature field to the strip camber. Furthermore, a feedforward compensation strategy was proposed based on the predicted strip camber deviation, using the roll offset and bending force as control parameters. Multi-objective optimisation was employed to determine the optimal combination of process parameters for each strip. Simulation and experimental validation on the downstream stands of a 2250 mm hot continuous finishing mill demonstrate that the developed model accurately captures the thermal expansion behaviour of the rolls, and the compensation strategy effectively reduces strip camber, thereby improving strip flatness. This study provides a systematic theoretical framework and technical support for the high-precision intelligent control of hot-rolled strip flatness.