Roll bending force using method for controlling deviation of strip steel by hot rolling finishing set

The invention relates to a roll bending force using method for controlling deviation of strip steel by a hot rolling finishing set and belongs to the field of metal rolling. A heat inductor is arranged behind a flying shear. Before a head of the strip steel enters the flying shear, racks of a finishing mill operate by using a normal roll bending force value; when the head of the strip steel moves forward to the position of the heat inductor, the heat inductor outputs a head position signal; the roll bending forces of the racks F1 and F2 in the finishing mill are increased to the maximum value; when occluding steel occurs on the rack F2, the roll bending force of the rack F1 is decreased to a normal level; when occluding steel occurs on the rack F3, the roll bending force of the rack F2 is decreased and recovered to the normal level. When the strip steel penetrates and occludes, the first and second racks of finish rolling use an extreme roll bending force to alleviate asymmetrical rolling under an inertia for