Method for setting rolling mill, and rolling mill

A method for setting a rolling mill,

• the rolling mill being a rolling mill of four-high or more that includes a plurality of rolls including at least a pair of work rolls and a pair of backup rolls supporting the work rolls,
• with a plurality of rolls provided on an upper side in a vertical direction with respect to a workpiece taken as an upper roll assembly,
• a plurality of rolls provided on a lower side in the vertical direction with respect to the workpiece taken as a lower roll assembly, and
• any one roll among respective rolls arranged in the vertical direction adopted as a reference roll,
• wherein the rolling mill comprises:
• torque measurement load cells which measure a torque acting on the work rolls that is generated by driving of a motor that drives the work rolls, respectively;
• vertical roll load measurement load cells which are provided on a work side and a drive side on at least a lower side or an upper side of the rolling mill and which measure a vertical roll load in the vertical direction, respectively;
• a first hydraulic cylinder which, with respect to at least roll chocks of the rolls other than the reference roll, is provided on either one of an entrance side and an exit side in a rolling direction, and which presses the roll chocks in a rolling direction of a workpiece;
• and
• a second hydraulic cylinder which, with respect to at least roll chocks of the rolls other than the reference roll, is provided so as to face the first hydraulic cylinder in the rolling direction, and which moves the roll chocks in a rolling direction of a workpiece;
• the method for setting a rolling mill being executed before reduction position zero point adjustment or before starting rolling, and including:
• a first process of:
• setting a roll gap between the work rolls in an open state, and with respect to each of the upper roll assembly and the lower roll assembly,
• in a roll assembly on a side on which the vertical roll load measurement load cells are installed, measuring a torque acting on the work roll by means of the torque measurement load cells, or measuring a vertical roll load in two different rotational states of the pair of work rolls on the work side and the drive side, respectively, by means of the vertical roll load measurement load cells,
• in a roll assembly on a side on which the vertical roll load measurement load cells are not installed, measuring a torque acting on the work roll by means of the torque measurement load cells, and
• fixing a rolling direction position of roll chocks of the reference roll as a reference position, and moving roll chocks of the rolls other than the reference roll by means of the second hydraulic cylinder based on the torque or a vertical roll load difference that is a difference between a vertical roll load on the work side and a vertical roll load on the drive side, to thereby adjust positions of the roll chocks;
• and
• a second process of:
• after performing the first process, setting the work rolls in a kiss roll state,
• measuring a vertical roll load in two different rotational states of the pair of work rolls on the work side and the drive side, respectively, by means of the vertical roll load measurement load cells, and
• fixing a rolling direction position of roll chocks of the reference roll as a reference position, and moving the roll chocks of each roll of a roll assembly on an opposite side to the reference roll by means of the second hydraulic cylinder simultaneously and in a same direction while maintaining relative positions between the roll chocks so that the vertical roll load difference is within a predetermined allowable range, to thereby adjust positions of the roll chocks.