PLATE THICKNESS CONTROLLING METHOD OF STEEL STRIP

PURPOSE:To improve the plate thickness accuracy by applying a slight strain to a strip in the entry of the first stand, deriving a strain quantity and a yield stress, and deriving a deformation resistance, a frictional resistance, etc. of the strip in each stand, based on its operating value. CONSTITUTION:A tension leveler 12 is provided in front of the entry of the first stand S1, a slight strain is applied to a strip 3, and also a plate speed (v) and a tension T of the entry and the delivery of the leveler 12 are measured by a plate speed meter 5 and a tension meter 7. An operator 15 calculates a strain quantity applied by the leveler 12 from a difference of the entry and the delivery of the plate speed (v), and a computer 13 calculates a deformation resistance and a frictional resistance in each stand of the strip 3 from a difference of the tension T, an original plate thickness, etc. Subsequently, a rolling down force of each stand is derived, and a plate thickness of the strip 3 is brought to feed forward control, by which the accuracy of a plate thickness containing a discontinuous part of the strip 3 is improved.