Research On The Distribution Of Asymmetric Plate's Rolling Pressure

Rolling accuracy has been the research hot spot during the last 20 years, the interesting mainly focused on the thickness and shape control. Rolling force model has an important role in the thickness and shape control model. The existing theory to solve the rolling pressure includes two-dimensional rolling theory, variation method (VM), finite element method (FEM) and strip element method (SEM). The lateral thickness difference of incoming plate has been ignored by the two-dimensional rolling theory, so the lateral distribution of the parameters about rolling area such as the rolling pressure has been difficult to express. The effect of lateral thickness difference to the lateral distribution of rolling pressure has been discussed by the VM and the SEM. However, during the actual calculation, the lateral distribution of incoming plate's thickness has been assumed symmetrical by the VM and the SEM, symmetric function has been used to fit the lateral distribution of the entry and exit plate's thickness. But the paper for the rolling pressure under asymmetric situation can be rarely found.In view of that, non-symmetric function has been used to fit the lateral distribution of the entry and exit plate's thickness in this article. First, in response to the differences of the elastic deformation between the up and down roller systems, the model of deformation of the whole rollers has been built. Then, the rolling force model has been established by the VM and the SEM. At last, the integrated calculation of the rolling pressure model has been built due to the SEM rolling force model and the model of deformation of the whole rollers. The following work has been done in this article:(1) Because the lateral distribution of the rolling pressure is not uneven since the lateral distribution of the incoming plate's thickness is left-right asymmetry, non-symmetric function used to fit the lateral distribution of the entry and exit plate's thickness. The lateral distribution of the non-symmetric plate's thickness has been calculated by the model of deformation of the whole rollers, in which the deformation of roller body and the load of roller neck and roller body have been dispersed. The top and bottom rollers elastic deformations for the different stiffness of the single housing have been analyzed on this basis. At last, simulation has been done in response to the symmetrical and asymmetric rolling situation.(2) The whole rolling area has been modeled based on the VM, in which non-symmetric function has been used to fit the lateral distribution of the entry and exit plate's thickness. Then simulation has been done in response to the symmetrical and asymmetric rolling situation.(3) The whole rolling area has been modeled based on the SEM, in which non-symmetric function has been used to fit the lateral distribution of the entry and exit plate's thickness. Due to the flow path of metal in the rolling area, the rolling area has been dispersed into number of flow line element. The model of metal deformation resistance used is more accurate. The model of friction has been derived by the mixed friction theory. (4) The rolling force model established by SEM has been iterated with the model of deformation of the whole rollers, which the integrated calculation of the rolling pressure model has been deduced. In response to the situation of three typical incoming plates such as flat piece, wedge-shaped piece and convex piece, simulation has been done on 3500mm×Φ750/Φ1500mm four-high aluminum mill under full working condition. Finally, the effect of the plate's thickness, reduction rate, width, convexity and lateral thickness difference to the lateral distribution of rolling pressure has been discussed.