Calculation and analysis of rolling force during aluminum alloy thick plate snake/gradient temperature rolling with different roll diameters

The central deformation extent of the thick plate can be improved and the approaching uniform deformation will be realized by the snake/gradient temperature rolling (SGTR). At present, the existing rolling force analytical models cannot be directly used for SGTR because of the great difference with the synchronous rolling. The rolling force model should be established so as to meet the production demand of the SGTR with different roll diameters. The thick plate is divided into three layers according to the numerical results of the short-term ultra-fast cooling for the thick plate. The deformation region is simplified into different zones and layers according to the temperature gradient and neutral point position. The traditional von Mises yield criterion was optimized by the introduced coefficients c₁ and c₂ according to the slip line field theory to correct the deviation caused by the uniform and shear stress assumption. The specific pressure equation is established by the slab method. The deformation region with different composition cases is analyzed, and the rolling force and torque analytical models are established according to the boundary conditions on this basis. The short-term ultra-fast cooling and rolling process were simulated by ANSYS software. The deformation resistance gradient produced by short-term ultra-fast cooling and roll diameter ratio are the main factors to affect the rolling force, while the roll offset has little effect on the rolling force because of its small proportion in the deformation region. The position of neutral points not only affects the rolling torque, but also changes its direction in certain conditions. The model precision was analyzed, and the rolling force calculated by the established analytic model is in good agreement with the numerical method, which serves as a theoretical basis for the rolling mill design and process parameter setting.