Abstract: Provided is a nozzle header which sprays pressurized water to a high-temperature object, capable of inhibiting a member provided to spray nozzles from being deformed or damaged by heat at the time of operation, caused by radiation heat from the high-temperature object. The nozzle header for spraying water to a targeted object includes a header which supplies pressurized water, one or more of spray nozzles which spray the pressurized water supplied from the header, and a heat removal structure attached so as to be in contact with at least one of the spray nozzles, wherein the heat removal structure includes a coolant passage through which a cooling medium for cooling the heat removal structure itself and the spray nozzles passes.

Abstract: Provided is a cooling apparatus discharging water smoothly corresponding to increase of volume density of cooling water securing a high cooling capability. The apparatus disposed on downstream side from a row of hot finish rolling mill, supplying cooling water from above toward a pass line, includes a plurality of cooling nozzles arranged parallel in a pass line direction, and an upper surface guide disposed between the pass line and the cooling nozzles, wherein a predetermined relation is satisfied when defining: a volume density of cooling water sprayed as qm(m3/(m2·sec)); a pitch of the cooling nozzle in the pass line direction as L(m); a distance between a lower surface of the upper surface guide and the pass line as hp(m); a uniform cooling width as Wu(m); and a cross-sectional area of virtual flow path of discharging water flowing in a width direction of steel sheet as S(m2).

Abstract: Provided is a nozzle incorporating a valve, which easily improves durability. The nozzle for spraying water to a targeted object, including a nozzle body provided with a passage of water and a valve arranged inside the passage of the nozzle body, wherein at least a part of an inner surface of the passage including a portion to have contact with the valve is coated by diamond-like carbon.

Abstract: Provided is a nozzle header which sprays pressurized water to a high-temperature object, capable of inhibiting a member provided to spray nozzles from being deformed or damaged by heat at the time of operation, caused by radiation heat from the high-temperature object. The nozzle header for spraying water to a targeted object includes a header which supplies pressurized water, one or more of spray nozzles which spray the pressurized water supplied from the header, and a heat removal structure attached so as to be in contact with at least one of the spray nozzles, wherein the heat removal structure includes a coolant passage through which a cooling medium for cooling the heat removal structure itself and the spray nozzles passes.

Abstract: Provided is a nozzle incorporating a valve, which easily improves durability. The nozzle for spraying water to a targeted object, including a nozzle body provided with a passage of water and a valve arranged inside the passage of the nozzle body, wherein at least a part of an inner surface of the passage including a portion to have contact with the valve is coated by diamond-like carbon.

Abstract: Provided is a cooling system for a hot-rolled steel strip capable of increasing the cooling rate for rapidly cooling a rolled steel immediately after rolling and suitable for an apparatus for manufacturing a hot-rolled steel strip having a fine-grained structure. For this purpose, guides (16A, 16B) having guiding surfaces (16a, 16b) to guide a rolled steel (W) exiting work rolls (12A, 12B) in the conveyance direction are provided at exits of the work rolls in a final stand (Sn) of a finish rolling mill line in a manner that the guides can follow a change in the diameter of the work rolls, a number of injection holes (21A, 21B) are formed in the guides, and a number of rolled steel cooling nozzles (23A, 23B) are provided to spray a large amount of cooling water through the injection holes directly onto the rolled steel.

Abstract: Provided is a cooling apparatus discharging water smoothly corresponding to increase of volume density of cooling water securing a high cooling capability. The apparatus disposed on downstream side from a row of hot finish rolling mill, supplying cooling water from above toward a pass line, includes a plurality of cooling nozzles arranged parallel in a pass line direction, and an upper surface guide disposed between the pass line and the cooling nozzles, wherein a predetermined relation is satisfied when defining: a volume density of cooling water sprayed as qm(m3/(m2·sec)); a pitch of the cooling nozzle in the pass line direction as L(m); a distance between a lower surface of the upper surface guide and the pass line as hp(m); a uniform cooling width as Wu(m); and a cross-sectional area of virtual flow path of discharging water flowing in a width direction of steel sheet as S(m2).

Abstract: Provided is a cooling system for a hot-rolled steel strip capable of increasing the cooling rate for rapidly cooling a rolled steel immediately after rolling and suitable for an apparatus for manufacturing a hot-rolled steel strip having a fine-grained structure. For this purpose, guides (16A, 16B) having guiding surfaces (16a, 16b) to guide a rolled steel (W) exiting work rolls (12A, 12B) in the conveyance direction are provided at exits of the work rolls in a final stand (Sn) of a finish rolling mill line in a manner that the guides can follow a change in the diameter of the work rolls, a number of injection holes (21A, 21B) are formed in the guides, and a number of rolled steel cooling nozzles (23A, 23B) are provided to spray a large amount of cooling water through the injection holes directly onto the rolled steel.

Abstract: A manufacturing apparatus comprises a final stand, with standing side members, and a cooling apparatus. The cooling apparatus comprises rows of upper surface cooling nozzles, rows of lower surface cooling nozzles, and an upper surface guide on the upper surface side of the steel sheet. An end portion of the cooling apparatus on a side of the final stand is arranged between the standing side members of the housing. When defining a width of a uniformly cooled region, an average gap distance (Wsw) between the end portion of the width of the uniformly cooled region and the standing side member of the housing; a gravity acceleration rate, an average water volume density of the width of the uniformly cooled region, and a value determined by Wsw and an average distance h between the upper surface guide and the upper surface of the steel sheet, a specific relation is satisfied.

Abstract: The present invention provides a cooling apparatus of a hot-rolled steel sheet capable of manufacturing a hot-rolled steel sheet having ultra fine crystal grains. In the cooling apparatus, when defining as L1, a length in a transporting direction of a steel sheet, of a zone from a rolling reduction point in a final stand to an exit side of a housing post; defining as L2, a length in the transporting direction of the steel sheet, of an area where high-pressure water is continuously sprayed over the steel sheet, within the zone; and defining a ratio of L2/L1 as X, an average value Ps [kPa], in the transporting direction of the steel sheet, of an impact pressure of the high-pressure water on a surface of the steel sheet in the area of the length L2 satisfies Ps?2.5X(?1/0.6) on the above upper surface and lower surface of the steel sheet.

Abstract: A cooling apparatus of a steel sheet, which is excellent in discharging water without hindering the movement of a steel sheet, is disposed on a lower process side of a final stand in a row of hot finish rolling mills. The apparatus includes a plurality of cooling nozzles arranged to cool a steel sheet transported on transporting rolls, wherein the cooling nozzles are arranged on upper and lower surface sides of an area in which the steel sheet passes. A lower surface guide is arranged on the lower surface side with the lower surface guide comprising inlet holes through which cooling water sprayed from the cooling nozzles on the lower surface side passes and outlet holes through which the cooling water passes, dropping downwardly to be discharged. The inlet holes and the outlet holes are arranged alternately in a moving direction of the steel sheet.

Abstract: A cooling apparatus of a steel sheet, which is excellent in discharging water without hindering the movement of a steel sheet, is disposed on a lower process side of a final stand in a row of hot finish rolling mills. The apparatus includes a plurality of cooling nozzles arranged to cool a steel sheet transported on transporting rolls, wherein the cooling nozzles are arranged on upper and lower surface sides of an area in which the steel sheet passes. A lower surface guide is arranged on the lower surface side with the lower surface guide comprising inlet holes through which cooling water sprayed from the cooling nozzles on the lower surface side passes and outlet holes through which the cooling water passes, dropping downwardly to be discharged. The inlet holes and the outlet holes are arranged alternately in a moving direction of the steel sheet.

Abstract: A manufacturing apparatus comprises a final stand, with standing side members, and a cooling apparatus. The cooling apparatus comprises rows of upper surface cooling nozzles, rows of lower surface cooling nozzles, and an upper surface guide on the upper surface side of the steel sheet. An end portion of the cooling apparatus on a side of the final stand is arranged between the standing side members of the housing. When defining a width of a uniformly cooled region, an average gap distance (WSW) between the end portion of the width of the uniformly cooled region and the standing side member of the housing; a gravity acceleration rate, an average water volume density of the width of the uniformly cooled region, and a value determined by WSW and an average distance h between the upper surface guide and the upper surface of the steel sheet, a specific relation is satisfied.

Abstract: The present invention provides a cooling apparatus of a hot-rolled steel sheet capable of manufacturing a hot-rolled steel sheet having ultra fine crystal grains. In the cooling apparatus, when defining as L1, a length in a transporting direction of a steel sheet, of a zone from a rolling reduction point in a final stand to an exit side of a housing post; defining as L2, a length in the transporting direction of the steel sheet, of an area where high-pressure water is continuously sprayed over the steel sheet, within the zone; and defining a ratio of L2/L1 as X, an average value Ps [kPa], in the transporting direction of the steel sheet, of an impact pressure of the high-pressure water on a surface of the steel sheet in the area of the length L2 satisfies Ps?2.5X(?1/0.6) on the above upper surface and lower surface of the steel sheet.