GAGE CONTROL METHOD FOR TANDEM ROLLING MILL

PROBLEM TO BE SOLVED: To provide a gage control method for a tandem rolling mill by which the gage on the outlet side is always controlled constant even in the case that fluctuation in hardness which does not appear on an original sheet as fluctuation in immanent. SOLUTION: The fluctuation in hardness which is immanent in the original sheet is estimated from the change in the gage before and after a sheet is passed through a stand of the early stage of the tandem rolling mill. The tracking of the estimated hardness is performed together with that of the gage and the feedforward control of the tension of the steel sheet at a stand in the later stage so that the change of the plastic curve of the steel sheet caused by the fluctuation in hardness is cancelled. In this way, the intersection of a mill stretch curve and the plasticity curve is kept constant like the case that there is no fluctuation in hardness and the sheet thickness gage on the outlet side is stabilized. COPYRIGHT: (C)2004,JPO