Gauge control method and apparatus for multi-roll rolling mill

Abstract

Gauge control method and apparatus for a multi-roll type upright rolling mill includes displaceable rolls which are movable not only in a first direction in which a material to be rolled is compressed but also in the axial direction thereof or in a direction in which the axis of the displaceable roll is inclined at a variable angle relative to other rolls as viewed in a horizontal plane, the other rolls being movable in the first direction. Position of the displaceable rolls is detected, and in dependence on the displacement of the displaceable roll, coefficient of mill stiffness of the whole rolling mill and those among the individual rolls are arithmetically determined. A roll gap defined between the rolls serving for rolling work is arithmetically determined on the basis of the arithmetically determined coefficients of stiffness, rolling load, and roll bending forces applied to the individual rolls detected by respective detectors. Rolling reduction set by a screw-down device of the rolling mill is controllably regulated in dependence on the roll gap. A high precision gauge control is realized by considering variations in the coefficients of mill stiffness brought about by the roll shifts and changes in the roll bending forces.