Abstract: A meandering control device and hot rolling equipment suppress a meandering amount of a hot-rolled steel strip. A roll opening degree difference between an operation side and a driving side in an i-th rolling machine computed in a leveling control computation step (step S3) in the meandering control method, satisfies the roll opening degree difference between the operation side and the driving side in the i-th rolling machine (Fi) by Expressions (1), (2), and (3) in a control section j, in a case where the control section j is set when a tail end portion (Sa) of a traveling hot-rolled steel strip (10) is present between a j-th (j?i?1) rolling machine (Fj) and a (j+1)th rolling machine (Fj+1) counting from a rolling machine (F1) installed on a most upstream side.

Abstract: A meandering amount arithmetically operating device of a meandering amount measurement device calculates the meandering amount of a steel sheet using a drive side edge site zds(N) and a work side edge sites zws(N) at a current time when a measurement reliability determination unit determines that both the drive side edge site zds(N) and the work side edge sites zws(N) at the current time have high reliability. When only one of the drive side edge site zds(N) and the work side edge site zws(N) at the current time is determined to have high reliability, the other edge site is calculated by interpolation using the number of pixels W from a sheet width updating unit with the drive side edge sites zds(N) or the work side edge site zws(N) at the current time having high reliability as a reference.

Abstract: A meandering control method for steel strip includes: an imaging step of imaging the surface of a traveling steel strip using a line sensor camera installed between adjacent rolling mills; a meandering amount calculation step of calculating the meandering amount of the steel strip by detecting the positions of both end portions in the width direction of the steel strip from a one-dimensional brightness distribution based on the captured image; and a leveling control arithmetic operation step of arithmetically operating a roll opening difference between the operation and drive sides of the rolling mill located on the immediately downstream side of the line sensor camera based on the calculated meandering amount. The imaging is performed in a period of 5 msec or less.

Abstract: A meandering control method for steel strip includes: an imaging step of imaging the surface of a traveling steel strip using a line sensor camera installed between adjacent rolling mills; a meandering amount calculation step of calculating the meandering amount of the steel strip by detecting the positions of both end portions in the width direction of the steel strip from a one-dimensional brightness distribution based on the captured image; and a leveling control arithmetic operation step of arithmetically operating a roll opening difference between the operation and drive sides of the rolling mill located on the immediately downstream side of the line sensor camera based on the calculated meandering amount. The imaging is performed in a period of 5 msec or less.

Abstract: A meandering control device and hot rolling equipment suppress a meandering amount of a hot-rolled steel strip. A roll opening degree difference between an operation side and a driving side in an i-th rolling machine computed in a leveling control computation step (step S3) in the meandering control method, satisfies the roll opening degree difference between the operation side and the driving side in the i-th rolling machine (Fi) by Expressions (1), (2), and (3) in a control section j, in a case where the control section j is set when a tail end portion (Sa) of a traveling hot-rolled steel strip (10) is present between a j-th (j?i?1) rolling machine (Fj) and a (j+1)th rolling machine (Fj+1) counting from a rolling machine (F1) installed on a most upstream side.

Abstract: A hot-rolled steel sheet not exceeding a coil opener allowable load during unwinding includes a steel sheet cut in unsteady portions at its longitudinal head and tail ends in a cutting step after a rough rolling step, having a width of 1,200 mm to 2,300 mm, a thickness of 13 mm to 25.4 mm, and at least an API standard X65-grade strength, and used in a state of being unwound after having been wound around a coil. A longitudinal end corresponding to the unwinding start includes a portion at its widthwise center recessed inwards in the longitudinal direction with respect to its two widthwise ends, the two widthwise ends projection sizes with respect to the recessed portion at the widthwise center are 20 to 295 mm, and the sum of the widths of projecting portions at the two widthwise ends is set to ¼ to ½ of the sheet width.

Abstract: A method for manufacturing a hot-rolled steel sheet having a large thickness and a large width, a larger sheet width and a lower temperature can stably be cut at a cutting load equal to that of a conventional steel sheet having a usual sheet thickness, a usual sheet width and a usual temperature. In a rough rolling step, the steel sheet is formed so that the shortest length L (mm) from a concave portion bottom to a convex portion top of the fishtail shape satisfies Equation (1) mentioned below, and an intermediate portion between the concave portion bottom and the convex portion top, defined as a desired cutting location, is cut: (2X+30)?L?300??(1), in which X is a maximum deviation (mm) of the cutting location of a crop cutting machine and 0?X?90.

Abstract: A hot-rolled steel sheet not exceeding a coil opener allowable load during unwinding includes a steel sheet cut in unsteady portions at its longitudinal head and tail ends in a cutting step after a rough rolling step, having a width of 1,200 mm to 2,300 mm, a thickness of 13 mm to 25.4 mm, and at least an API standard X65-grade strength, and used in a state of being unwound after having been wound around a coil. A longitudinal end corresponding to the unwinding start includes a portion at its widthwise center recessed inwards in the longitudinal direction with respect to its two widthwise ends, the two widthwise ends projection sizes with respect to the recessed portion at the widthwise center are 20 to 295 mm, and the sum of the widths of projecting portions at the two widthwise ends is set to ¼ to ½ of the sheet width.

Abstract: A method for manufacturing a hot-rolled steel sheet having a large thickness and a large width, a larger sheet width and a lower temperature can stably be cut at a cutting load equal to that of a conventional steel sheet having a usual sheet thickness, a usual sheet width and a usual temperature. In a rough rolling step, the steel sheet is formed so that the shortest length L (mm) from a concave portion bottom to a convex portion top of the fishtail shape satisfies Equation (1) mentioned below, and an intermediate portion between the concave portion bottom and the convex portion top, defined as a desired cutting location, is cut: (2X+30)?L?300??(1), in which X is a maximum deviation (mm) of the cutting location of a crop cutting machine and 0?X?90.