Development of simulation system of strip flatness for hot tandem mill

Using three-dimensional rigid-plastic finite element method base on Lagrange multiplier to analyze the deformation of strip,influence function method to calculate the elastic deflection of rolls and three-dimensionalelastic FEM to analyze the flattening deformation between work roll and strip,a coupled model was established with a iteration way.The effect of various kinds flatness control method such as bending force,rolls shift and cross angle and also various kind of influence factors such as friction coefficient,strip crown,rolls wear and thermo-crown on strip flatness can be analyzed using this coupled model.A great deal of information for example outlet crown of the strip,front and back tension,rolling force distribution for per length,rolls elastic deformation and forward slip can be obtained.In order to improve computational efficiency,the average change of rolling force for per unit length was added into the criterion to determine if the coupled process is end,which can save 30 percent computing time for one pass but the changes of strip thickness is not large than 5μm.The exploration has certain conductive significance for improving efficiency of other type of mill.