Cooling device for hot rolled steel sheet and cooling method for the same

Patent metadata

Field	Value
Publication number	US-2020055105-A1
Application number	US-201716484765-A
Country	US
Kind code	A1
Filing date	Mar 31, 2017
Priority date	Mar 31, 2017
Publication date	Feb 20, 2020
Grant date	—

Abstract

A cooling device cooling an undersurface of a hot rolled steel sheet that is being transported on transport rolls after finish rolling of a hot rolling step includes: width divided cooling zones that are a plurality of cooling zones into which a whole cooling zone is divided in a sheet width direction; divided cooling sections that are a plurality of cooling zones into which each of the width divided cooling zones is divided in the rolling direction; a water nozzle spraying cooling water over each of undersurfaces of the divided cooling sections; a switching mechanism switching the cooling water between impinging and not impinging on the divided cooling sections; a width direction thermometer measuring a temperature distribution in the sheet width direction; and a controller controlling operation of the switching mechanism.

First claim

1 . A cooling device cooling an undersurface of a hot rolled steel sheet that is being transported on transport rolls after finish rolling of a hot rolling step, the cooling device comprising:
width divided cooling zones that are a plurality of cooling zones into which a whole cooling zone is divided in a sheet width direction, the whole cooling zone being a cooling zone partitioned by all of a width of an undersurface of a sheet transport zone in the sheet width direction and a predetermined length of the undersurface of the sheet transport zone in a rolling direction; divided cooling sections that are a plurality of cooling zones into which each of the width divided cooling zones is divided in the rolling direction; at least one cooling water nozzle spraying cooling water over each of undersurfaces of the divided cooling sections; a switching mechanism switching the cooling water sprayed from the cooling water nozzle between impinging and not impinging on the divided cooling sections; a width direction thermometer measuring a temperature distribution in the sheet width direction; and a controller controlling operation of the switching mechanism based on a result of measurement with the width direction thermometer.

2 . The cooling device according to claim 1 , wherein
said at least one cooling water nozzle is arranged correspondingly to each of the divided cooling sections.

3 . The cooling device according to claim 1 ,
wherein the number of the cooling water nozzles arranged for each of the divided cooling sections are different between adjacent divided cooling sections in the rolling direction.

4 . The cooling device according to claim 1 ,
wherein lengths of the divided cooling sections included in one of the width divided cooling zones are different from each other in the rolling direction.

5 . The cooling device according to claim 1 ,
wherein the lengths of the divided cooling sections in the rolling direction are multiples of a length between the transport rolls.

6 . The cooling device according to claim 1 ,
wherein a plurality of the cooling water nozzles in the sheet width direction are arranged in such a way that center to center distances of adjacent cooling water nozzles in the sheet width direction are all equal.

7 . The cooling device according to claim 1 ,
wherein a plurality of the cooling water nozzles for cooling each of the divided cooling sections are arranged, and the switching mechanism integratively controls a switching control system switching the cooling water from the plurality of the cooling water nozzles between impinging and not impinging on each of the divided cooling sections at once.

8 . The cooling device according to claim 1 , the switching mechanism comprising:
a water supply header supplying the cooling water, the water supply header being provided for piping in which the cooling water supplied to the cooling water nozzles flows; a draining header or draining area draining the cooling water; and a valve switching a flow of the cooling water between the water supply header and the draining header or draining area.

9 . The cooling device according to claim 8 ,
wherein the valve is a three way valve, the valve being provided on a side of the transport rolls in the sheet width direction, the valve being arranged at a same height as tops of the cooling water nozzles.

10 . The cooling device according to claim 1 , the switching mechanism comprising:
a water supply header supplying the cooling water, the water supply header being provided for piping in which the cooling water supplied to the cooling water nozzles flows; a draining area draining the cooling water; a means changing a direction of a jet of the cooling water that is sprayed from the cooling water nozzles; and a means such that the cooling water does not impinge on the divided cooling sections when the direction of the jet is changed, wherein the means changing the direction of the jet of the cooling water makes it possible to switch the cooling water between impinging on and not impinging on the undersurfaces of the divided cooling sections.

11 . The cooling device according to claim 1 ,
wherein the width direction thermometer is provided on at least one of an upstream side and a downstream side of the whole cooling zone in the rolling direction, the width direction thermometer being provided for each of the width divided cooling zones.

12 . The cooling device according to claim 11 ,
wherein the width direction thermometer is arranged on the side of the undersurface of the steel sheet transport zone.

13 . A method for cooling an undersurface of a hot rolled steel sheet that is being transported on transport rolls after finish rolling of a hot rolling step, the method comprising:
defining
a whole cooling zone as a cooling zone partitioned by all of a width of an undersurface of a sheet transport zone in a sheet width direction and a predetermined length of the undersurface of the sheet transport zone in a rolling direction,
width divided cooling zones as a plurality of cooling zones into which the whole cooling zone is divided in the sheet width direction, and
divided cooling sections as a plurality of cooling zones into which each of the width divided cooling zones is divided in the rolling direction;
measuring a temperature distribution of the hot rolled steel sheet in the sheet width direction; and controlling the cooling water from a cooling water nozzle impinging and not impinging on the hot rolled steel sheet for each of the divided cooling sections in each of the sheet width direction and the rolling direction based on a result of said measuring the temperature distribution.

14 . The cooling method according to claim 13 ,
wherein a plurality of the cooling water nozzles spraying the cooling water are provided for each of the divided cooling sections, and the plurality of the cooling water nozzles are integrated to control the cooling water from the plurality of the cooling water nozzles impinging and not impinging on part of the hot rolled steel sheet is controlled at once, the part being over each of the divided cooling sections.

15 . The cooling method according to claim 13 , the method further comprising:
using a structure comprising:
a water supply header supplying the cooling water, the water supply header being provided for piping in which the cooling water supplied to the cooling water nozzles flows,
a draining header or draining area draining the cooling water, and
a valve switching a flow of the cooling water between the water supply header and the draining header or draining area; and
controlling open and close of the valve based on the result of said measuring the temperature distribution of the hot rolled steel sheet in the width direction, to control the cooling water from the cooling water nozzles impinging and not impinging on the hot rolled steel sheet for each of the divided cooling sections in each of the sheet width direction and the rolling direction.

16 . The cooling method according to claim 15 ,
wherein the valve is a three way valve supplying the cooling water to middle headers, the cooling water being supplied from the water supply header, for the middle headers each of the cooling water nozzles being provided, an opening degree of the three way valve provided for any of the middle headers that does not allow the cooling water from the cooling water nozzles to impinge on the undersurface of the hot rolled sheet is controlled so that the cooling water from the cooling water nozzles continues to flow

Assignees

• Nippon Steel Corp

Inventors

• Haraguchi Yohichi
• Serizawa Yoshihiro
• Honda Tatsuro
• Tachibana Hisayoshi
• Nakagawa Susumu
• Tanaka Koki
• Ishitsuka Shota

Classifications

• B21C51/00

  Measuring, gauging, indicating, counting, or marking devices specially adapted for use in the production or manipulation of material in accordance with subclasses B21B - B21F · CPC title

• B21B2261/21

  Temperature profile · CPC title

• B21B37/74 Primary

  Temperature control, e.g. by cooling or heating the rolls or the product (B21B37/32, B21B37/44 take precedence) · CPC title

• B21B45/0233 Primary

  Spray nozzles, Nozzle headers; Spray systems · CPC title

• B21B2263/08

  Centre buckles · CPC title