US 11,701,697 B2
Cooling device for hot-rolled steel sheet and cooling method of hot-rolled steel sheet
Hiroshi Niitani, Tokyo (JP); Nobumasa Hayashi, Tokyo (JP); Rumi Matsumoto, Tokyo (JP); Yoshihiro Serizawa, Tokyo (JP); Tomofumi Hosho, Tokyo (JP); Takumu Ushizawa, Tokyo (JP); and Naoko Katou, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/275,511
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Sep. 10, 2019, PCT No. PCT/JP2019/035581
§ 371(c)(1), (2) Date Mar. 11, 2021,
PCT Pub. No. WO2020/059577, PCT Pub. Date Mar. 26, 2020.
Claims priority of application No. JP2018-174870 (JP), filed on Sep. 19, 2018.
Prior Publication US 2022/0032352 A1, Feb. 3, 2022
Int. Cl. B21B 45/02 (2006.01); B21B 39/14 (2006.01); B21B 37/74 (2006.01)
CPC B21B 45/0218 (2013.01) [B21B 37/74 (2013.01); B21B 39/14 (2013.01); B21B 45/0233 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A cooling method of a hot-rolled steel sheet that uses a cooling device including a table having a cooling target region to cool a top surface of a hot-rolled steel sheet conveyed on conveyor rolls after hot rolling, wherein
the cooling target is a region demarcated by a cooling machine length and a full width in a width direction, or a region obtained by excluding a non-cooling region in a middle portion in the width direction from the demarcated region and is set as an entire cooling region, and wherein the cooling target region includes regions obtained by dividing the entire cooling region into three or more portions in the width direction which are set as width-divided cooling zones, and regions obtained by dividing the width-divided cooling zone into a plurality of portions in a machine length direction which are set as divided cooling surfaces,
the cooling device includes:
for each of the divided cooling surfaces, at least one cooling water nozzle that jets cooling water to the divided cooling surface to form a cooling water collision region on the top surface of the cooling target region,
the cooling water collision region overlaps an other cooling water collision region adjacent thereto in the width direction in the entire cooling region to form a cooling water collision region group in which the cooling water collision regions are connected in the width direction,
each of the cooling water collision region groups does not overlap an other cooling water collision region group,
the full width of the entire cooling region in the width direction is covered with the cooling water collision region group or a pair of the cooling water collision region groups adjacent to each other in the machine length direction, and
the cooling water nozzles forming the cooling water collision region group have a jet axis inclined with respect to a vertical line to the top surface of the cooling target region when viewed in the machine length direction, and none of the cooling water nozzles forming the cooling water collision group has the jet axis inclined in the opposite direction when viewed in the machine length direction, the cooling method comprising:
measuring a width-direction temperature distribution of the cooling target region;
controlling, for each of the width-divided cooling zones, collision and non-collision of cooling water from the cooling water nozzle with each of a plurality of the divided cooling surfaces contained in the width-divided cooling zone based on measurement results of the width-direction temperature distribution of the cooling target region, thereby controlling cooling for the entire length of the width-divided cooling zone in the machine length direction, and controlling cooling of the entire cooling region; and
letting cooling water jetted from the cooling water nozzle go to the side opposite to the cooling water nozzle in the width direction to drain the cooling water.