To obtain a cold-rolled steel strip excellent in shape accuracy by performing feedforward control using a numerical formula model taking the variation of rolling load as a variable in a rolling speed decelerating region and a rolling speed accelerat ing region before and after the changing point of kinds to be manufactured passes through the final rolling stand.
When performing continuous cold rolling by successively welding feeding plural material to be rolled in a continuous cold-rolling mill in which plural rolling stands are arranged in tandem, a numerical formula model by which the variation of elongation-percentage difference is expressed to the middle of width of plural places having different distances from the end of the sheet taking the variation of the rolling load as variables is preliminarily prepared. Within the period from the rolling speed decelerating region to the rolling speed accelerating region before and after the changing point of the kinds to be manufactured passes through the final rolling stand, the predicted value of the variation of the rolling load is substituted in the numerical formula, the control value of a work roll bender and/or an intermediate roll bender is set or corrected so that the variation of the elongation-percentage difference is made to coincide with the target value. In the rolling speed decelerating region and rolling speed accelerating region, feedforeward control based on signals from a shape detector can be combined.
HARA KENJI
MAEDA KANEICHIRO
HAYAKAWA JUNYA
