Abstract: A rolling mill of four-high or more is provided that includes: measurement apparatuses that adopt any one roll as a reference roll, and measure at least rolling direction forces acting on roll chocks on a work side and roll chocks on a drive side of each roll other than a backup roll; pressing apparatuses that press the roll chocks in the rolling direction; driving apparatuses that move the roll chocks in the rolling direction; and a position control unit that fixes a rolling direction position of the roll chocks of the reference roll as a reference position, and drives the driving apparatuses to control the positions in the rolling direction of the roll chocks based on a rolling direction force difference so that the rolling direction force difference of each roll is a value within an allowable range.

Abstract: A slab manufacturing method in which casting drum housing screw-down system deformation characteristics which have been acquired prior to the start of slab casting and which indicate deformation characteristics of a housing configured to support a casting drum and deformation characteristics of a screw-down system configured to screw down the casting drum is used to calculate an estimated plate thickness at both end portions of a slab in a width direction thereof from Expression 1 ((estimated plate thickness on entry side of rolling mill)=(screw-down position of casting cylinder)+(elastic deformation of casting drum)+(casting drum housing screw-down system deformation)+(drum profile of casting drum)?(elastic deformation of casting drum at time of screw-down position zero-point adjustment)), an entry-side wedge ratio and an exit-side wedge ratio are calculated on the basis of the estimated plate thickness calculated from Expression 1.

Abstract: There is provided a zigzagging control method for a workpiece 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 and a material-roll thrust force estimated based on a material-roll cross angle and a material-roll friction coefficient; and a tail control step of, during the rolling of the tail portion of the workpiece, 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 a rolling mill based on the corrected rolling load difference or rolling load difference ratio.

Abstract: There is provided a method for identifying thrust counterforce working point positions of backup rolls of a rolling mill, the method including: changing at least either friction coefficients and inter-roll cross angles between the rolls with an unchanged kiss roll load to cause thrust forces at a plurality of levels to act between the rolls, and measuring thrust counterforces in a roll-axis direction acting on rolls forming at least one of roll pairs other than a roll pair of the backup rolls and measuring backup roll counterforces acting in a vertical direction on the backup rolls at reduction support positions in a kiss roll state; and identifying, based on the measured thrust counterforces, thrust counterforce working point positions of thrust counterforces acting on the backup rolls, using first equilibrium conditional expressions relating to forces acting on the rolls and second equilibrium conditional expressions relating to moments acting on the rolls.

Abstract: There is provided a rolling mill that includes a plurality of rolls, in which any one roll among respective rolls is adopted as a reference roll, including a load detection apparatus, detects a vertical roll load at a rolling support point position; a pressing apparatus pressing the roll chocks in the rolling direction; a driving apparatus moving the roll chocks in the rolling direction; and a position control unit which fixes a rolling direction position of roll chocks of the reference roll, and drives the driving apparatus to control positions in the rolling direction of the roll chocks of the rolls other than the reference roll.

Abstract: A method for setting a rolling mill, the method being executed before reduction position zero point adjustment or before the start of rolling, and including: a first process of setting rolls in an open state, and with respect to each of the upper roll assembly and the lower roll assembly, adjusting positions of roll chocks in a rolling direction based on a torque acting on the work roll or a vertical roll load difference; and a second process of, after the first process, setting rolls in a kiss roll state, measuring a vertical roll load in two rotational states on a work side and a drive side, and moving roll chocks of a roll assembly on the opposite side to a reference roll simultaneously and in a same direction so that the vertical roll load difference falls within an allowable range to thereby adjust the positions of the roll chocks.

Abstract: There is provided a zigzagging control method for a workpiece 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 and a material-roll thrust force estimated based on a material-roll cross angle and a material-roll friction coefficient; and a tail control step of, during the rolling of the tail portion of the workpiece, 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 a rolling mill based on the corrected rolling load difference or rolling load difference ratio.

Abstract: A slab casting method using a twin-drum continuous casting device manufactures a slab by solidifying molten metal by a pair of rotating casting drums includes calculating estimated sheet thicknesses on both ends in a width direction of the slab from equation 1 ((estimated sheet thickness)=(cylinder screw down position)+(elastic deformation of casting drum)+(casting drum housing screw down system deformation)+(drum profile of casting drum)?(elastic deformation of casting drum at the time of screw down position zero adjustment)) by using a casting drum housing screw down system deformation characteristic indicating a deformation characteristic of housings that support the casting drums and a deformation characteristic of a screw down system that screws down the casting drums obtained before casting of the slab starts, and controlling screw down positions of cylinders provided on both ends in a width direction of the casting drums.

Abstract: There is provided a method for identifying thrust counterforce working point positions of backup rolls of a rolling mill, the method including: changing at least either friction coefficients and inter-roll cross angles between the rolls with an unchanged kiss roll load to cause thrust forces at a plurality of levels to act between the rolls, and measuring thrust counterforces in a roll-axis direction acting on rolls forming at least one of roll pairs other than a roll pair of the backup rolls and measuring backup roll counterforces acting in a vertical direction on the backup rolls at reduction support positions in a kiss roll state; and identifying, based on the measured thrust counterforces, thrust counterforce working point positions of thrust counterforces acting on the backup rolls, using first equilibrium conditional expressions relating to forces acting on the rolls and second equilibrium conditional expressions relating to moments acting on the rolls.

Abstract: The present invention provides a method for identifying an inter-roll cross angle in a rolling mill of four-high or more including at least a pair of work rolls and a pair of backup rolls by, when rolling is not performed, applying a roll bending force to apply a load between rolls of an upper roll assembly including the work roll on the upper side and between rolls of a lower roll assembly including the work roll on the lower side, in a state where a roll gap between the work rolls is put into an open state, detecting vertical roll loads that act in the vertical direction on the rolling support positions on the working side and the driving side of at least one of the backup roll on the upper side or the backup roll on the lower side, and calculating a load difference between the vertical roll loads on the working side and the driving side.

Abstract: A slab manufacturing method in which casting drum housing screw-down system deformation characteristics which have been acquired prior to the start of slab casting and which indicate deformation characteristics of a housing configured to support a casting drum and deformation characteristics of a screw-down system configured to screw down the casting drum is used to calculate an estimated plate thickness at both end portions of a slab in a width direction thereof from Expression 1 ((estimated plate thickness on entry side of rolling mill)=(screw-down position of casting cylinder)+(elastic deformation of casting drum)+(casting drum housing screw-down system deformation)+(drum profile of casting drum)?(elastic deformation of casting drum at time of screw-down position zero-point adjustment)), an entry-side wedge ratio and an exit-side wedge ratio are calculated on the basis of the estimated plate thickness calculated from Expression 1.

Abstract: A rolling mill of four-high or more is provided that includes: measurement apparatuses that adopt any one roll as a reference roll, and measure at least rolling direction forces acting on roll chocks on a work side and roll chocks on a drive side of each roll other than a backup roll; pressing apparatuses that press the roll chocks in the rolling direction; driving apparatuses that move the roll chocks in the rolling direction; and a position control unit that fixes a rolling direction position of the roll chocks of the reference roll as a reference position, and drives the driving apparatuses to control the positions in the rolling direction of the roll chocks based on a rolling direction force difference so that the rolling direction force difference of each roll is a value within an allowable range.

Abstract: There is provided a rolling mill that includes a plurality of rolls, in which any one roll among respective rolls is adopted as a reference roll, including a load detection apparatus, detects a vertical roll load at a rolling support point position; a pressing apparatus pressing the roll chocks in the rolling direction; a driving apparatus moving the roll chocks in the rolling direction; and a position control unit which fixes a rolling direction position of roll chocks of the reference roll, and drives the driving apparatus to control positions in the rolling direction of the roll chocks of the rolls other than the reference roll.

Abstract: A method for setting a rolling mill, the method being executed before reduction position zero point adjustment or before the start of rolling, and including: a first process of setting rolls in an open state, and with respect to each of the upper roll assembly and the lower roll assembly, adjusting positions of roll chocks in a rolling direction based on a torque acting on the work roll or a vertical roll load difference; and a second process of, after the first process, setting rolls in a kiss roll state, measuring a vertical roll load in two rotational states on a work side and a drive side, and moving roll chocks of a roll assembly on the opposite side to a reference roll simultaneously and in a same direction so that the vertical roll load difference falls within an allowable range to thereby adjust the positions of the roll chocks.

Abstract: This manufacturing method for a slab is a method for manufacturing a slab by a continuous casting equipment including a twin-drum type continuous casting apparatus, a cooling apparatus, an in-line mill, and a coiling apparatus. The method includes calculating a friction coefficient from measured values of a rolling load and a forward slip when the slab is rolled, by use of a rolling analysis model, and controlling a lubrication condition during rolling of the slab so that the friction coefficient falls within a predetermined range, wherein, when the friction coefficient is calculated from the measured values of the rolling load and the forward slip by use of an Orowan theory and a deformation resistance model formula based on a Shida's approximate formula as the rolling analysis model, the predetermined range is 0.15 or more and 0.25 or less.

Abstract: The present invention provides a method for identifying an inter-roll cross angle in a rolling mill of four-high or more including at least a pair of work rolls and a pair of backup rolls by, when rolling is not performed, applying a roll bending force to apply a load between rolls of an upper roll assembly including the work roll on the upper side and between rolls of a lower roll assembly including the work roll on the lower side, in a state where a roll gap between the work rolls is put into an open state, detecting vertical roll loads that act in the vertical direction on the rolling support positions on the working side and the driving side of at least one of the backup roll on the upper side or the backup roll on the lower side, and calculating a load difference between the vertical roll loads on the working side and the driving side.

Abstract: Provided is a manufacturing apparatus and manufacturing method of hot-rolled steel sheet which enables uniform cooling of a rolled material and improvement of the surface properties thereof. The manufacturing apparatus comprises: a rolling stand; a supplying device capable of supplying lubricant to work rolls and/or backup rolls; an online roll grinding device; and a removing device capable of removing at least part of the lubricant before the surface of the work rolls is ground by the grinding device. The manufacturing method comprises the steps of: removing at least part of the lubricant adhered to the work rolls, or to the work rolls and backup rolls using the lubricant removing device after completing rolling of a preceding material; grinding the work rolls using the online roll grinding device after the removing step; and supplying the lubricant to the work rolls and/or backup rolls from the lubricant supplying device.

Abstract: Provided is a method of controlling operation of a tandem rolling mill which enables large reduction rolling in the latter-stage stand of the tandem rolling mill necessary for manufacturing fine-grained steel, and so on. The method comprises: a step of determining a first exit-side sheet thickness in rolling a constant portion of a material to be rolled; and a step of determining a second exit-side sheet thickness in rolling a front end portion of the material, such that a pre-tightening load becomes a set value or less; the material is rolled into the second exit-side sheet thickness, until the front end portion is fed into the stands; the constant portion is rolled by the stand given a pre-tightening load into the first exit-side sheet thickness; and the second exit-side sheet thicknesses of the stands given the pre-tightening load are made larger than the first exit-side sheet thickness.

Abstract: Provided is a method of controlling operation of a tandem rolling mill which enables large reduction rolling in the latter-stage stand of the tandem rolling mill necessary for manufacturing fine-grained steel, and so on. The method comprises: a step of determining a first exit-side sheet thickness in rolling a constant portion of a material to be rolled; and a step of determining a second exit-side sheet thickness in rolling a front end portion of the material, such that a pre-tightening load becomes a set value or less; the material is rolled into the second exit-side sheet thickness, until the front end portion is fed into the stands; the constant portion is rolled by the stand given a pre-tightening load into the first exit-side sheet thickness; and the second exit-side sheet thicknesses of the stands given the pre-tightening load are made larger than the first exit-side sheet thickness.

Abstract: Provided is a manufacturing apparatus and manufacturing method of hot-rolled steel sheet which enables uniform cooling of a rolled material and improvement of the surface properties thereof. The manufacturing apparatus comprises: a rolling stand; a supplying device capable of supplying lubricant to work rolls and/or backup rolls; an online roll grinding device; and a removing device capable of removing at least part of the lubricant before the surface of the work rolls is ground by the grinding device. The manufacturing method comprises the steps of: removing at least part of the lubricant adhered to the work rolls, or to the work rolls and backup rolls using the lubricant removing device after completing rolling of a preceding material; grinding the work rolls using the online roll grinding device after the removing step; and supplying the lubricant to the work rolls and/or backup rolls from the lubricant supplying device.