Side spray method for cooling the steel strip after hot rolling

Abstract

A side spray method for cooling a steel strip after hot rolling includes providing side spray devices behind multiple cooling sections on two sides in a width direction of a run out roller table of the steel strip after hot rolling. The side spray devices are staggered along the two sides of the run out roller table of the steel strip, the side spray devices include at least two spray units, each spray unit includes a spray tube and nozzles on the spray tube, the spray tubes being in parallel and vertically arranged along a running direction of the steel strip, and being movable along the running direction of the steel strip, covering ranges of the nozzles on the side spray devices are partially overlapped with each other, and a total spray coverage covering of nozzles covers a width of the run out roller table of the steel strip.

Claims

1. A side spray method for cooling a steel strip after hot rolling, the side spray method comprising: a) providing side spray devices behind multiple cooling sections on two sides in a width direction of a run out roller table of the steel strip after hot rolling, wherein the side spray devices are staggered along the two sides of the run out roller table of the steel strip, the side spray devices include at least two spray units, each spray unit includes a spray tube and nozzles on the spray tube, the spray tubes being in parallel and vertically arranged along a running direction of the steel strip, and being movable along the running direction of the steel strip, covering ranges of the nozzles on the side spray devices are partially overlapped with each other, and a total spray coverage covering of nozzles covers a width of the run out roller table of the steel strip, side spray water collecting devices being provided on an other side of the run out roller table of the steel strip that is opposite to side spray devices, so that side spray water being collected by the water collecting devices; and b) controlling the side spray devices in a mode of open-in-pairs, wherein the cooling sections and side spray devices are numbered in the running direction of the steel strip after hot rolling such that each of the cooling sections is numbered as an odd number or an even number in the running direction of the steel strip after hot rolling, when a valve at the cooling sections with the odd number is opened, two consecutive staggered side spray devices behind the cooling sections are opened at a same time, and when the valve at the cooling sections with the even number is opened, the side spray device behind the cooling sections has been already open, and no further side spray device needs to be open.

2. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein, when each side spray device has N spray units and N≥2, N spray units have N spray tubes, each spray tube is provided with one nozzle, and the width of the roller table of the steel strip is represented by Wg, a projection of each nozzle along the width of the roller table is named as water spray coverage of nozzle Ws, formula Ws≥Wg/N is satisfied, and wherein an angle between a spray direction of the nozzle and the running direction of the steel strip is named as direction angle α, and N nozzles on the side spray devices are designated as 1˜N along the running direction of the steel strip, the direction angle α from a first to Nth nozzles is set as from large to small, and the direction angle α of the 1st to (N−1)th nozzles is from 110° to 165°, and the direction angle α of the Nth nozzle is from 75° to 105°.

3. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein the nozzles on the side spray devices are designated as 1˜N along the running direction of the steel strip, and given a sequence number n, that is, n=1˜N, and a direction angle of the Nth nozzle is named as α.sub.n, length of water spray coverage of an Nth nozzle on a surface of the steel strip is L.sub.n satisfies L.sub.n=Ws/sin(180°−α.sub.n), and installation spacing S.sub.n between an (N+1)th nozzle and the Nth nozzle satisfies S.sub.n=Ws/tan(180°−α.sub.n)−Ws/tan(180°−α.sub.n+1) when the direction angle of the Nth nozzle α.sub.N<90°, the installation spacing: S.sub.N−1=Ws/tan(180°−α.sub.N−1)+Ws/tan(α.sub.N).

4. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein a height h from the nozzle on the side spray device to a surface of the steel strip is set as 300˜700 mm, and the nozzles on the side spray device are designated in the running direction of the steel strip by 1˜N, and the height of the first to the Nth nozzles is set from low to high.

5. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein the nozzles on the side spray device are designated by 1˜N in the running direction of the steel strip, and given serial number n, that is, n=1˜N, and an incident angle R satisfies: 1st nozzle's incident angle β.sub.1=90°; nth nozzle's incident angle β.sub.n=arctan(h.sub.n/((n−1)×L.sub.n)), wherein n>1, h.sub.n is an nth nozzle height and L.sub.n is nth nozzle water spray coverage length, nth nozzle's scattering angle θ.sub.n=arctan((n×L.sub.n)/h.sub.n)−(90°−β.sub.n), wherein n>0, h.sub.n is the nth nozzle height, L.sub.n is the water spray coverage length and β.sub.n is the incident angle.

6. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein the side spray device has 2 to 5 spray units.

7. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein the coverage of the nozzles on each side spray device has a certain overlap.

8. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein the spray tube on a spray member is of a lifting design, so that the nozzle on the spray tube can be lifted up and down.

9. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein the side spray water collecting device is a box body having an opening on one side that is corresponding to the side spray device, and at least two anti-collision arc plates are provided vertically on an opening side of the box body at intervals along a longitudinal direction, and a bottom plate of the box body is tilted, and provided with drainage hole.

10. The side spray method for cooling the steel strip after hot rolling according to claim 9, wherein an opening side of the side spray water collecting device box body is provided with vertical anti-collision arc plates at both sides, respectively.

11. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein the nozzle on a spray member is rotatable, and can rotate up, down, left and right.

12. The side spray method for cooling the steel strip after hot rolling according to claim 1, wherein the side spray device includes: water collecting pipe, connecting with water source through pipeline; and at least two spray units with nozzles, where the spray tubes on the spray units are vertically arranged along a longitudinal direction of the water collecting pipe, and are movably connected to a fixed bracket through connecting piece, respectively, and are connected to the water collecting pipe through a hose, the spray tubes are adjustable for spacing, height and angle.

13. The side spray method for cooling the steel strip after hot rolling according to claim 12, wherein the spray tubes on the side spray device are supplied with water through a water collecting pipe or a separate water inlet, and a water pressure and a flow rate are controlled independently.

14. The side spray method for cooling the steel strip after hot rolling according to claim 12, wherein the water pressure of the water collecting pipe of the side spray device is 1.0 MPa to 2.0 MPa, and the flow rate is 10 m.sup.3/h to 20 m.sup.3/h.

15. The side spray method for cooling the steel strip after hot rolling according to claim 12, wherein the spray unit is provided with an adjustable ball joint for adjusting a nozzle incident angle, including a nozzle forward inclination angle, and wherein the nozzle is connected to the ball joint.

16. The side spray method for cooling the steel strip after hot rolling according to any claim 1, wherein the nozzle is a fan nozzle or a tongue nozzle.

Description

FIGURE DESCRIPTION

(1) FIG. 1 is a schematic diagram of the cooling arrangement of the hot-rolled steel strip after rolling of the present invention.

(2) FIG. 2 is a schematic structural diagram of the side spray device of the present invention.

(3) FIG. 3 is a schematic diagram of the side spray water collecting device of the present invention.

(4) FIG. 4 is a schematic diagram of a single nozzle side spray of the present invention. In-picture marking: α-direction angle; β-incident angle; θ-scattering angle; h-height of nozzle from nozzle; L-watermark length; Ws-water spray coverage of the side spray; Wg-width of the roller table.

(5) FIG. 5 is a schematic diagram of the effect of the guided side spray of the present invention.

DETAILED DESCRIPTION

(6) As shown FIG. 1-FIG. 5, the side spray method for cooling the steel strip after hot cooling, comprising the following steps: a) providing side spray devices 30, 30′, 30″ behind multiple cooling sections 20, 20′, 20″ on both sides of run out roller table 10 of the steel strip after hot rolling, wherein the side spray devices 30, 30′, 30″ are staggered along the two sides of run out roller table 10 of the steel strip, the side spray devices include at least two spray units along the running direction of the steel strip, each spray unit includes spray tube and nozzles on the tube, one of the nozzles can be fixed and the other nozzles being movable along the running direction of the steel strip; the covering ranges of the nozzles on the side spray devices are partially overlapped, and a total spray coverage covering of the nozzles covers the width of the steel strip roller table; side spray water collecting devices 30, 30′, 30″ are provided on the other side of run out roller table 10 of the steel strip that is opposite to side spray devices 40, 40′, 40″, so that side spray water being collected by the water collecting devices 40, 40′, 40″; b) controlling the side spray devices 30, 30′, 30″ in a mode of open-in-pairs, wherein multiple cooling sections and side spray devices are numbered in the running direction of the steel strip after hot rolling, when the valve at the cooling sections with odd number is opened, the valves of two consecutive staggered side spray devices behind the cooling sections are opened at the same time; when the valve at the cooling sections with even number is opened, the side spray device behind the cooling sections has been already open, and no further side spray device needs to be open.

(7) As shown FIG. 3, the side spray water collecting device 40 of the present invention is a box body having an opening on one side that is corresponding to the side spray device, and at least two anti-collision arc plates 401 are provided vertically on the opening side of the box body at intervals along the longitudinal direction, and the bottom plate of the box body is tilted, and provided with drainage hole 402.

(8) Preferably, the opening side of the box body is provided with vertical anti-collision arc plates 401′ at both sides, respectively.

(9) Preferably, the nozzle on the spray member is rotatable, and can rotate up, down, left and right.

(10) As shown FIG. 2, the side spray devices 30 (take side spray device 30 as example, the same below) of the present invention comprising,

(11) Water collecting pipe 1, connecting with water source through pipeline;

(12) Three spray tubes 2, 2′, 2″ with nozzles are vertically arranged along the length of the water collection pipe 1, one of spray tube 2 is fixed and connected to the water collecting pipe 1; spray tubes 2′, 2″ are movably connected to the fixed bracket 4 through connecting pieces 3, 3′, respectively, the spray tubes 2′, 2″ are adjustable for spacing, height and angle, and connected to the water collecting pipe 1 through hoses 5, 5′.

(13) Preferably, the spray tubes on the side spray device are supplied with water through a water collecting pipe or separate water inlet, and the water pressure and flow rate are controlled independently.

(14) Preferably, the water supply pressure of the water collecting pipe of the side spray device is 1.0 MPa to 2.0 MPa, and the flow rate is 10 m.sup.3/h to 20 m.sup.3/h.

(15) Preferably, the spray unit is provided with an adjustable ball joint for adjusting the nozzle incident angle, i.e., the nozzle forward inclination angle, and the nozzle is connected to the ball joint.

(16) Preferably, the nozzle is a fan nozzle or a tongue nozzle.

(17) As shown FIG. 4, the spray direction of the nozzle and the running direction of the steel strip is recorded as the direction angle α, can be adjusted by turning the ball joint left and right rotation; the angle formed by the water spray of the nozzle near the side spray device and the steel plate is the incident angle β, can be adjusted by turning the ball joint left and right rotation and the nozzle up and down; the scattering angle θ is the inherent characteristic of the nozzle, which is shaped according to the design angle. By changing the direction angle and the incident angle, the watermark length L and the water spray coverage of the side spray Ws can be adjusted so that the side spray water covers the entire width of the roller table Wg.

(18) As shown FIG. 5, under the barrier and guidance of the three-dimensional water wall formed by the nozzles 1 and 2, the residual water on the steel strip surface flows to the other side of the roller table, and finally leave the steel strip surface under the guidance and impact of the nozzle 3 to enter the side spray water collecting device.

Example 1

(19) The width of the roller table can be a variety of widths, such as 1050 mm, 1250 mm, 1350 mm, 1450 mm, 1580 mm, 1700 mm, 1800 mm, 1880 mm, 2050 mm, 2250 mm, 2300 mm, but not limited thereto.

(20) Take a width of the roller table with 1800 mm cooling zone of hot-rolling line as an example. (1) The side spray device is designed with three side spray tubes, that is three nozzles, each nozzle should cover at least the roller table range on the width direction Ws=1800 mm/3=600 mm. (2) According to the principle of guided side spray, the 1st nozzle's direction angle is set to 150°, and the watermark length on the surface of the steel strip is L.sub.1: L.sub.1=600/sin(180°−150°)=1200 mm, 2nd nozzle's direction angle is set to 135°, and the distance to 1st nozzle is S.sub.1: S.sub.1=600/tan(180°−150°)−600/tan(180°−135°)=439 mm, Watermark length L.sub.2 of 2nd nozzle on the steel strip surface: L.sub.2=600/sin(180°−135°)=848.5 mm, 3rd nozzle mainly plays a strong sweeping function, the direction angle is set to 90°, and the distance to 2nd nozzle is S.sub.2: S.sub.2=600/tan(180°−135°)−0=600 mm, Watermark length L.sub.3 of 3rd nozzle on the steel strip surface: L.sub.3=600/sin(180°−90°)=600 mm Total spacing S between three nozzles: S=S.sub.1+S.sub.2=439+600=1039 mm, There are three rollers' spacing between the two cooling sections of the cooling roller table. The single roller's spacing is 360 mm and the total length is 360 mm×3=1080 mm. It is just right to install the side spray device. If the spacing between the cooling sections is insufficient to install, the direction angle can be adjusted appropriately to shorten the spacing between nozzles. (3) The distance from the nozzle to the steel strip surface is set to h.sub.1=400 mm, h.sub.2=500 mm, h.sub.3=600 mm. (4) According to the height h of the side nozzle and the watermark length L, the incident angle of each side nozzle is determined: 1st nozzle's incident angle β.sub.1=90° 2nd nozzle's incident angle β.sub.2=arctan(h.sub.2/(2−1)×L.sub.2))=arctan(500/848.5)=30.5° 3rd nozzle's incident angle β.sub.3=arctan(h.sub.3/((3−1)×L.sub.3))=arctan(600/1200)=26.6° (5) According to the height h of the side nozzle, the watermark length L and the incident angle β, the scattering angle θ of each side nozzle is determined: 1st nozzle's scattering angle θ.sub.1=arctan(L.sub.1/h.sub.1)−(90°−β.sub.1)=arctan(1200/400)=71.6° 2nd nozzle's scattering angle θ.sub.2=arctan(2×L.sub.2/h.sub.2)−(90°−β.sub.2)=arctan(2×848.5/500)−(90°−30.5°)=14.1° 3rd nozzle's scattering angle θ.sub.3=arctan(3×L.sub.3/h.sub.3)−(90°−β.sub.3)=arctan(3×600/600)−(90°−26.6°)=8.2°.

(21) In order to improve the water blocking and dewatering effect, the watermark of each nozzle should have a certain overlap, so the calculation results should be optimized with appropriately increasing the incident angle and the scattering angle.

(22) 2nd nozzle's incident angle β.sub.2=35°

(23) 3rd nozzle's incident angle β.sub.3=30°

(24) 2nd nozzle's scattering angle θ.sub.2=arctan(848.5×2/500)−(90°−35°)=18.6°

(25) 3rd nozzle's scattering angle θ.sub.3=arctan(600×3/600)−(90°30°)=11.6°.

Example 2

(26) Take a width of the roller table with 1050 mm cooling zone of hot-rolling line as an example.

(27) (1) The side spray device is designed with three side spray tubes, that is three nozzles, each nozzle should cover at least the roller table range on the width direction Ws=1050 mm/3=350 mm.

(28) (2) According to the principle of guided side spray, 1st nozzle's direction angle is set to 165°, and the watermark length on the surface of the steel strip is L.sub.1:

(29) L.sub.1=350/sin(180°−165°)=1352 mm,

(30) 2nd nozzle's direction angle is set to 150°, and the distance to 1st nozzle is S.sub.1:

(31) S.sub.1=350/tan(180°−165°)−350/tan(180°−150°)=700 mm,

(32) Watermark length L.sub.2 of 2nd nozzle on the steel strip surface:

(33) L.sub.2=350/sin(180°−150°)=700 mm,

(34) 3rd nozzle mainly plays a strong sweeping function, the direction angle is set to 105°, and the distance to 2nd nozzle is S.sub.2:

(35) S.sub.2=350/tan(180°−150°)−350/tan(180°−105°)=512 mm,

(36) Watermark length L.sub.3 of 3rd nozzle on the steel strip surface:

(37) L.sub.3=350/sin(180°−105°)=362 mm

(38) Total spacing S between three nozzles:

(39) S=S.sub.1+S.sub.2=700+512=1212 mm,

(40) There are three rollers' spacing between the two cooling sections of the cooling roller table. The single roller's spacing is 420 mm and the total length is 420 mm×3=1260 mm. It is just right to install the side spray device. If the spacing between the cooling sections is insufficient to install, the direction angle can be adjusted appropriately to shorten the spacing between nozzles.

(41) (3) The distance from the nozzle to the steel strip surface is set to h.sub.1=400 mm, h.sub.2=500 mm, h.sub.3=600 mm.

(42) (4) According to the height h of the side nozzle and the watermark length L, the incident angle of each side nozzle is determined:

(43) 1st nozzle's incident angle β.sub.1=90°

(44) 2nd nozzle's incident angle β.sub.2=arctan(h.sub.2/(2−1)×L.sub.2))=arctan(500/700)=35.5°

(45) 3rd nozzle's incident angle β.sub.3=arctan(h.sub.3/((3−1)×L.sub.3))=arctan(600/724)=39.6°.

(46) (5) According to the height h of the side nozzle, the watermark length L and the incident angle β, the scattering angle θ of each side nozzle is determined:

(47) 1st nozzle's scattering angle θ.sub.1=arctan(L.sub.1/h.sub.1)−(90°−β.sub.1)=arctan(1352/400)=73.5°

(48) 2nd nozzle's scattering angle θ.sub.2=arctan(2×L.sub.2/h.sub.2)−(90°−β.sub.2)=arctan(2×700/500)−(90°35.5°)=15.8°

(49) 3rd nozzle's scattering angle θ.sub.3=arctan(3×L.sub.3/h.sub.3)−(90°−β.sub.3)=arctan(3×362/600)−(90°−33.7°)=10.7°.

(50) In order to improve the water blocking and dewatering effect, the watermark of each nozzle should have a certain overlap, so the calculation results should be optimized with appropriately increasing the incident angle and the scattering angle.

(51) 2nd nozzle's incident angle β.sub.2=40°

(52) 3rd nozzle's incident angle β.sub.3=45°

(53) 2nd nozzle's scattering angle θ.sub.2=arctan(700×2/500)−(90°40°)=20.3°

(54) 3rd nozzle's scattering angle θ.sub.3=arctan(362×3/600)−(90°45°)=16.1°.

Example 3

(55) Take a width of the roller table with 2250 mm cooling zone of hot-rolling line as an example.

(56) (1) The side spray device is designed with three side spray tubes, that is three nozzles, each nozzle should cover at least the roller table range on the width direction Ws=2250 mm/3=750 mm.

(57) (2) According to the principle of guided side spray, 1st nozzle's direction angle is set to 135°, and the watermark length on the surface of the steel strip is L.sub.1:

(58) L.sub.1=750/sin(180°−135°)=1061 mm;

(59) 2nd nozzle's direction angle is set to 110°, and the distance to 1st nozzle is S.sub.1:

(60) S.sub.1=750/tan(180°−135°)−750/tan(180°−110°)=477 mm,

(61) Watermark length L.sub.2 of 2nd nozzle on the steel strip surface:

(62) L.sub.2=750/sin(180°−110°)=798 mm,

(63) 3rd nozzle mainly plays a strong sweeping function, the direction angle is set to 75°, and the distance to 2nd nozzle is S.sub.2:

(64) S.sub.2=750/tan(180°−110°)+750/tan(75°)=474 mm,

(65) Watermark length L.sub.3 of the 3rd nozzle on the steel strip surface:

(66) L.sub.3=750/sin(180°−105°)=776 mm

(67) Total spacing S between three nozzles:

(68) S=S.sub.1+S.sub.2=477+474=951 mm,

(69) There are three rollers' spacing between the two cooling sections of the cooling roller table. The single roller's spacing is 360 mm and the total length is 360 mm×3=1080 mm. It is just right to install the side spray device. If the spacing between the cooling sections is insufficient to install, the direction angle can be adjusted appropriately to shorten the spacing between nozzles.

(70) (3) The distance from the nozzle to the steel strip surface is set to h.sub.1=400 mm, h.sub.2=500 mm, h.sub.3=600 mm.

(71) (4) According to the height h of the side nozzle and the watermark length L, the incident angle of each side nozzle is determined:

(72) 1st nozzle's incident angle β.sub.1=90°

(73) 2nd nozzle's incident angle β.sub.2=arctan(h.sub.2/(2−1)×L.sub.2))=arctan(500/798)=32.1°

(74) 3rd nozzle's incident angle β.sub.3=arctan(h.sub.3/((3−1)×L.sub.3))=arctan(600/776)=37.7°.

(75) (5) According to the height h of the side nozzle, the watermark length L and the incident angle β, the scattering angle θ of each side nozzle is determined:

(76) 1st nozzle's scattering angle θ.sub.1=arctan(L.sub.1/h.sub.1)−(90°−β.sub.1)=arctan(1061/400)=69.3°

(77) 2nd nozzle's scattering angle θ.sub.2=arctan(2×L.sub.2/h.sub.2)−(90°−β.sub.2)=arctan(2×798/500)−(90°32.1°)=14.7°

(78) 3rd nozzle's scattering angle θ.sub.2=arctan(3×L.sub.3/h.sub.3)−(90°−β.sub.3)=arctan(3×776/600)−(90°−37.7°)=23.2°.

(79) In order to improve the water blocking and dewatering effect, the watermark of each nozzle should have a certain degree of overlap, so the calculation results should be optimized with appropriately increasing the incident angle and the scattering angle.

(80) 2nd nozzle's incident angle β.sub.2=35°

(81) 3rd nozzle's incident angle β.sub.3=40°

(82) 2nd nozzle's scattering angle θ.sub.2=arctan(798×2/500)−(90°35°)=17.6°

(83) 3rd nozzle's scattering angle θ.sub.3=arctan(776×3/600)−(90°−40°)=25.5°.

(84) A high-to-low three-dimensional water wall from one side of the side spray device to the other side of the roller table is formed by nozzle 1 and nozzle 2, which effectively blocks the residual water on the surface of the steel strip; and the side spray water has a lateral impact force, which can guide the residual water on the blocked surface of the steel strip to the other side of the roller table. These guided water flows will not only drive the more distant residual water to the other side of the roller table, but also suppress its splash; when the residual water on the surface of the steel strip is blocked by the three-dimensional water wall and guided to the other side near the roller table, it quickly leaves the surface of the steel strip under the strong impact and guidance of the nozzle 3 and enters the side spray water collecting device, because the impact point of the nozzle 3 and the residual water is close to the other side of the roller table, so it will not cause much splash. Therefore, the entire set of side spray devices can not only effectively sweep the residual water on the surface of the steel strip, but also reduce splashing.

(85) The above is the static calculation and optimization results. In actual application, due to the difference in the water volume of the cooling device and the change in the steel strip speed, it is necessary to adjust online based on the actual side spray effect based on the above design to adapt to the actual working conditions.