Rolling method for strip rolling mill and strip rolling equipment

A rolling method for a strip rolling mill, the strip rolling mill including a pair of upper and lower work rolls for rolling a strip of material, intermediate rolls for supporting each of the work rolls, back-up rolls for supporting each of the intermediate rolls, a work roll drive mechanism for moving the work rolls in directions of work roll axes, and an intermediate roll drive mechanism for moving the intermediate rolls in directions of intermediate roll axes, wherein each of the work rolls is provided with a tapered portion near one end thereof and the tapered portions of the work rolls are arranged on opposite sides of roll bodies thereof with respect to roll axis directions, the rolling method comprising the steps of:

• repeating a reversible rolling by reversing a rolling direction of the strip of material;
• and
• in order to allow an average of an actual edge drop value and a target edge drop value in at least one coil being rolled to almost agree, giving a command signal of fixed axial positions for the work rolls during the repeated reversible rolling based on differences between the actual edge drop value and the predetermined target edge drop value to the work roll drive mechanism to fix axial positions of the work rolls at the desired positions so that the work rolls are not axially moved and points at which the tapered portions of the work rolls start are within a width of the strip of material, and giving a command signal of axial displacement for the intermediate rolls during the repeated reversible rolling based on the differences between the actual edge drop value and the predetermined target edge drop value to the intermediate roll drive mechanism to change axial positions of the intermediate rolls to control a thickness distribution in a width direction of the strip of material being rolled.