Examination of Effective Factor on Curling and Curling Control in Plate Rolling

To realize a technique for the control of curling during plate rolling, the curling behavior in actual rolling was investigated by examining the real nature in an actual mill and by the deformation analysis of the plate during rolling based on rigid-plastic FEM. Main results were the following: (1) In addition to factors that has been investigated previously, the curling behavior is remarkably influenced by the asymmetry in the phase transformation and residual strain due to the asymmetrical temperature distribution in the thickness direction. (2) To control the asymmetry in these factors, it is necessary to control the asymmetrical temperature distribution in the thickness direction with a consideration of its effect upon these factors in not only rolling process, but also the preceding process of it. On the basis of the results obtained, effectiveness of a technique for controlling curling based on the control of the vertical temperature difference in the whole process, from reheating to rolling, was confirmed.