METHOD OF CONTROLLING MEANDERING OF MATERIAL-TO-BE-ROLLED

There is provided a zigzagging control method for a workpiece in which a rolling mill includes a plurality of rolls that include at least a pair of work rolls and at least a pair of backup rolls, the zigzagging control method including: an estimation step of, before rolling of a tail portion of the workpiece, acquiring at least any one of an inter-roll thrust force estimated based on an inter-roll cross angle and an inter-roll friction coefficient that are acquired through measurement or estimation and a material-roll thrust force estimated based on a material-roll cross angle and a material-roll friction coefficient that are acquired through measurement or estimation; and a tail control step of measuring work-side and drive-side rolling loads, correcting a rolling load difference or a rolling load difference ratio based on any two of acquired parameters including a roll-axis-direction thrust counterforce at the measurement of the rolling loads, the inter-roll thrust force, and the material-roll thrust force, and performing reduction leveling control on the rolling mill based on the corrected rolling load difference or rolling load difference ratio, the tail control step being performed during the rolling of the tail portion of the workpiece.