The aim of this diploma thesis is to research profile and flatness of hot rolled strips. The profile of the strip is described as the difference in thickness between the edge of the strip and its middle by width. The effects of bending of the rolls due to shear and bending stresses, the effect of change in the diameter of the work rolls by width due to mechanical and the effect of thermal expansion during rolling were closely studied. In order to ensure the flatness of the rolled material, the ratio between the thickness of the strip in the middle and the edge must remain constant during rolling. In the event that the reduction of thickness is greater on the edge then the middle of the strip, then that results in wavy edges. If the reduction is higher in the middle, then that results in central buckles of the strip. The influence of the strip profile during the first passes is minor as it is shown in diagrams of strip flatness. Flatness of the rolled strip in ensured in the last passes through the rolling mill.
Measurements were performed on electric steel of two different grades EV12 and EV21-P. Altogether 10 measurements were made, 5 of each grade. In the first phase of the experiment, flatness or waviness of the strip was being observed during rolling on the steckel rolling mill. In the second phase the parameters for the construction of the mathematical model, that calculates the bending of rolls due to shear and bending stresses while taking into account the change in roll radius due to mechanical grinding and thermal expansion were obtained and used. In the third phase diagrams that show flatness of the strip during each pass were constructed. The results of the third phase were compared with the observations from the first phase of the experiment.
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