The present invention relates to a steel plate cooling system and a steel plate
cooling method that cool a steel plate obtained by hot rolling while allowing the steel
10 plate to pass horizontally and restrictively between constraining rolls. j
Priority is claimed on Japanese Patent Application No. 2010-164522, filed July
22, 2010 and Japanese Patent Application No. 2010-234715, filed October 19, 2010, the
content thereof is incorporated herein by reference.
15 Background Art
[0002]
A hot steel plate after finish rolling of hot rolling is cooled to a predetermined
temperature while being constrained and conveyed between constraining rolls after a
finish rolling machine. A cooling system, for example, a plurality of spray nozzles that
20 sprays cooling water to the upper and lower surfaces, respectively, of the hot steel plate,
is arranged between respective constraining roll pairs, and the hot steel plate is cooled
using the cooling water. In the hot rolling of the hot steel plate, the aspect of cooling
after this finish rolling becomes an important factor that determines the mechanical
properties of the steel plate, workability, and weldability, and it is thus important to
25 uniformly cool the hot steel plate to a predetermined temperature.
[0003]
However, in a case where the hot steel plate is cooled using cooling water as
described above, on the upper surface side of the hot steel plate, it is difficult to
uniformly cool the hot steel plate due to the influence of water flow on a surface that
5 accumulates on the hot steel plate. That is, although the water on the surface on the hot
steel plate is discharged in the width direction of the hot steel plate, the water on the
surface interferes with a water jet stream of the cooling water sprayed onto the hot steel
plate. This makes the cooling water non-uniform in the width direction of the hot steel
plate.
10 [0004]
Thus, Patent Document 1 discloses a cooling method of adjusting the collision
area of the water jet stream from the spray nozzle or adjusting the spread angle of the
water jet stream, causing the water jet stream to sufficiently reach the upper surface of
the hot steel plate. In the case of this method, cooling capacity can be sufficiently
15 secured and the hot steel plate can be uniformly cooled.
[0005]
Here, in the hot rolling, the cooling capacity required for the cooling system
differs depending on the type, usage, or the like of the steel plate. Accordingly, the
cooling system is desired to be able to uniformly cool the hot steel plate as described
20 above, and select a cooling capacity control range across a broad range.
[0006]
For example, in a case where a required cooling capacity is low under this
situation, that is, in a case where the amount of cooling water sprayed onto the hot steel
plate is small, the nozzle load pressure of the spray nozzle becomes small. It is thereby
25 difficult to secure the area of a collision portion (hereinafter, referred to as a "spray
pattern") of the water jet stream from the spray nozzle to the hot steel plate. For this
reason, in the cooling method described in Patent Document 1, the water jet stream from
a spray nozzle is influenced by the water on the surface in the case where the cooling
water amount is small, and it is difficult to uniformly cool the hot steel plate.
5 [0007]
Thus, Patent Document 2 discloses a cooling system that has spray nozzles that
have different amounts of cooling water to be sprayed, and uses the spray nozzles
separately according to the required cooling capacity (cooling water amount). However,
since a water jet stream with a large amount of cooling water from a spray nozzle affects '
10 a water jet stream with a small amount of cooling water in a case where the difference
between the amounts of cooling water sprayed from the respective spray nozzles is large
when the upper surface of the hot steel plate is cooled, the cooling water becomes
non-uniform in the width direction of the hot steel plate. Since non-uniformity of
cooling occurs if the spray nozzles with different amounts of cooling water in this way
15 are simultaneously used, the conditions that the cooling system can be applied are limited
and the cooling capacity range may not be sufficiently broadened.
[0008]
Additionally, Patent Document 3 discloses a cooling system including air-water
spray nozzles that spray two fluids (air and cooling water) in order to secure a spray
20 pattern. However, the air-water spray nozzles need an air compressor, air piping, or the
like for supplying air, and thus the manufacturing costs of the cooling system become
high. Additionally, since the nozzle structure of the air-water spray nozzles is
complicated, and is apt to clog, maintenance costs also become high in addition to the
manufacturing costs of the cooling system. Moreover, the pressure control of air and
25 water is complicated, it is difficult to keep the air-water ratio constant, and the cooling
4
capacity changes depending on the air-water ratio. As such, the cooling system has a
problem of too many influencing factors, and it is difficult to perform precise cooling
capacity control.
5 Citation List
Patent Literature
[0009]
[Patent Document 1] Japanese Unexamined Patent Application, First
Publication No. 2006-82115
10 [Patent Document 2] Japanese Unexamined Patent Application, First
Publication No. 2007-301568
[Patent Document 3] Japanese Unexamined Patent Application, First
Publication No. 2006-219732
15 Summary of Invention
Problem to be Solved by the Invention
[0010]
The present invention has been invented in view of the above-described
problems, and an object thereof is to provide a steel plate cooling system and a steel plate
20 cooling method that uniformly cool the hot steel plate after hot rolling while broadly
controlling cooling capacity when the steel plate is cooled.
Means for solving the Problem
[0011]
25 The present invention has adopted the following means in order to solve the
*
5
above problems and achieve the relevant object.
That is,
(1) a steel plate cooling system related to one aspect of the present invention is a
steel plate cooling system including a plurality of constraining roll pairs that allows a
5 steel plate to pass restrictively therebetween; and an upper cooling apparatus and a lower
cooling apparatus that are arranged between the constraining roll pairs so as to be
opposed to each other with the steel plate interposed therebetween and have a plurality of
spray nozzle rows. The plurality of spray nozzle rows is formed in a plate passing
direction of the steel plate, and each of the spray nozzle rows has a plurality of identical
10 spray nozzles lined up in a width direction of the steel plate. When viewed in the plate
passing direction, the spray nozzle rows are each classified into an upstream spray nozzle
row group on a relative upstream side and a downstream spray nozzle row group located
on a relative downstream side. A number of spray nozzles that belong to the upstream
spray nozzle row group is smaller than a number of spray nozzles that belong to the
15 downstream spray nozzle row group.
[0012]
(2) In the steel plate cooling system described in the above (1), preferably, a
ratio of a total number of the respective spray nozzle rows and the number of spray
nozzle rows that belong to the upstream spray nozzle row group is equal to or an integer
20 ratio approaching the ratio of the maximum spraying amount and minimum spraying
amount of each spray nozzle that belongs to the spray nozzle rows.
[0013]
(3) The steel plate cooling system described in the above (1) preferably further
includes a control unit that controls a cooling water to be sprayed toward the steel plate
25 from the plurality of spray nozzle rows, and the control unit preferably controls the
spraying of the cooling water so that the cooling water is caused to be sprayed from both
the upstream spray nozzle row group and the downstream spray nozzle row group in a
case where a total amount of water to be sprayed toward the steel plate is equal to or
larger than a maximum spraying amount of the upstream spray nozzle row group, and the
5 cooling water is caused to be sprayed only from the upstream spray nozzle row group in
a case where the total amount of water is smaller than the maximum spraying amount of
the upstream spray nozzle row group.
[0014]
(4) The steel plate cooling system described in the above (3) preferably further
10 includes a water supply header that supplies the cooling water to the upstream spray
nozzle row group and the downstream spray nozzle row group; a flow rate regulating
valve that regulates the flow rate of the cooling water to be supplied to the water supply
header; a first control valve that controls a permission or prohibition of supply of the
cooling water to be supplied from the water supply header to the upstream spray nozzle
15 row group; and a second control valve that controls a permission or prohibition of supply
of the cooling water to be supplied from the water supply header to the downstream spray
nozzle row group.
[0015]
(5) The steel plate cooling system described in the above (1) preferably further
20 includes a first water supply header that supplies a cooling water to the upstream spray
nozzle row group; a second water supply header that supplies a cooling water to the
downstream spray nozzle row group; a first flow rate regulating valve that regulates a
flow rate of the cooling water to be supplied to the first water supply header; a second
flow rate regulating valve that regulates a flow rate of the cooling water to be supplied to
25 the second water supply header; and a control unit that controls the cooling water to be
7
sprayed toward the steel plate from the plurality of spray nozzle rows. The control unit
preferably controls the spraying of the cooling water so that the cooling water is caused
to be sprayed from both the upstream spray nozzle row group and the downstream spray
nozzle row group in a case where a total amount of water to be sprayed toward the steel
5 plate is equal to or larger than a maximum spraying amount of the upstream spray nozzle
row group, and the cooling water is caused to be sprayed only from the upstream spray
nozzle row group in a case where the total amount of water is smaller than the maximum
spraying amount of the upstream spray nozzle row group.
[0016]
10 (6) In the steel plate cooling system described in any one of the above (1) to (5),
preferably, a mutually adjacent intervals, in the plate passing direction, of the respective
spray nozzle rows that belong to the upstream spray nozzle row group are the same, and
wherein a mutually adjacent intervals, in the plate passing direction, of the respective
spray nozzle rows that belong to the downstream spray nozzle row group are the same.
15 [0017]
(7) In the steel plate cooling system described in any one of the above (1) to (5),
preferably, all the adjacent intervals of the respective spray nozzle rows in the plate
passing direction are the same.
[0018]
20 Incidentally, in a case where the total amount of cooling water to be sprayed
onto the upper surface of the steel plate is smaller than the maximum water amount of the
upstream spray row group, the amount of the water on the surface on the steel plate
becomes small, and the water on the surface is discharged in the plate passing direction
of the steel plate, that is, to the downstream side of the steel plate, with the movement of
25 the steel plate, and does not accumulate on the upstream side as much. For this reason,
8
the cooling water sprayed to the upstream side of the steel plate can cool the steel plate
uniformly without being influenced by the water on the surface.
In such a case and in a case where the water on the surface on the steel plate
accumulates on the constraining roll pair side on the downstream side of the steel plate,
5 (8) in the steel plate cooling system described in any one of the above (1) to (5), the
upstream spray nozzle row group may be arranged so that a cooling water is sprayed
from the upstream spray nozzle row group toward a position of the upstream side in the
plate passing direction not overlapped with a region of water on the surface that
accumulates on the steel plate when a maximum spraying amount is caused to be sprayed
10 from the upstream spray nozzle row group.
[0019]
(9) When a steel plate is cooled using the steel plate cooling system described in
any one of the above (1) to (5), the spraying of the cooling water may be controlled by
the control unit so that the cooling water is caused to be sprayed from both the upstream
15 spray nozzle row group and the downstream spray nozzle row group in a case where the
total amount of water to be sprayed toward the steel plate is equal to or larger than the
maximum spraying amount of the upstream spray nozzle row group, and the cooling
water is caused to be sprayed only from the upstream spray nozzle row group in a case
where the total amount of water is smaller than the maximum spraying amount of the
20 upstream spray nozzle row group.
[0020]
(10) In the steel plate cooling method described in the above (9), a region of
water on the surface that accumulates on the steel plate when the cooling water is caused
to be sprayed with the maximum spraying amount from the upstream spray nozzle row
25 group may be obtained in advance, and the upstream spray nozzle row group may be
9
arranged so that the cooling water is sprayed from the upstream spray nozzle row group
toward a position of the upstream side in the plate passing direction not overlapped with
the region.
5 Effects of the Invention
[0021]
According to the present invention, uniform cooling can be performed in a wide
cooling capacity range with a smaller number of spray nozzles, a smaller number of
nozzle rows, and a smaller number of flow rate regulating valves. Additionally, since
10 the facility configuration is simple, and there is one type of nozzle, reduction in facility
construction costs or reduction in maintenance costs can be achieved.
Brief Description of Drawings
[0022]
15 FIG 1 is a side view showing a schematic configuration of a portion of a
hot-rolling facility having a cooling system related to a first embodiment of the present
invention.
FIG 2 an explanatory view showing a schematic configuration in a longitudinal
cross-sectional view of an upper cooling apparatus of the cooling system.
20 FIG 3 an explanatory view showing a schematic configuration in a horizontal
cross-sectional view of the upper cooling apparatus of the cooling system.
FIG 4 is an explanatory view showing the condition in which cooling water is
sprayed from a spray nozzle of the cooling system.
FIG 5 is a graph showing the relationship between nozzle load pressure and
25 spray angle of the spray nozzle of the cooling system.
10
FIG 6 is a graph showing the relationship between nozzle load pressure and
cooling water amount of the spray nozzle of the cooling system.
FIG 7 is an explanatory view showing the relationship between the nozzle load
pressure of the spray nozzle of the cooling system, and the water amount density of the
5 cooling water supplied from the upper cooling apparatus.
FIG 8 is an explanatory view showing the condition in which a steel plate is
cooled in a case where required cooling capacity is high.
FIG 9 is an explanatory view showing the condition in which the steel plate is
cooled in a case where the required cooling capacity is low.
10 FIG 10 is an explanatory view of a case where cooling water is sprayed only
from a downstream spray nozzle row group.
FIG 11 is a graph that shows cooling rates in respective positions in the width
direction of the steel plate cooled using the cooling system.
FIG 12 is a side view showing an overall cooling system related to a second
15 embodiment of the present invention.
FIG 13 is a perspective view schematically showing a nozzle header of the
cooling system.
FIG 14 is a plan view showing the arrangement of cooling water spray nozzles
attached to the nozzle header of the cooling system.
20 FIG 15 is a graph showing the relationship between water supply amount
density and nozzle water supply pressure from a small-flow-rate nozzle header and a
large-flow-rate nozzle header.
Description of Embodiments
25 [0023]
11
[First Embodiment]
A first embodiment of the present invention will be described below. FIG. 1 is a side
view showing a schematic configuration of a portion of a hot-rolling facility having a
cooling system 1 related to the present embodiment.
5 [0024]
As shown in FIG 1, a finish rolling machine 2, a hot correcting device 3, and the
cooling system 1 are provided in this order in a plate passing direction of a steel plate
(hot steel plate) H in the hot-rolling facility. The rolling mill 2 hot-rolls the steel plate
H that is discharged from a heating furnace (not shown) and is rolled by a roughing
10 rolling machine (not shown). The hot correcting device 3 corrects the shape of the steel
plate H after finish rolling. The cooling system 1 cools the steel plate H after hot
correction to a predetermined temperature, for example, 350°C. This allows the steel
plate H rolled in the finish rolling machine 2 to be shape-corrected in the hot correcting
device 3 and then cooled by the cooling system 1 during conveyance.
15 In addition, a layout in which correction is made after cooling may be adopted,
that is, the hot correcting device 3 may be located on the downstream side (rear surface
side) of the cooling system 1. Otherwise, the hot correcting devices 3 may be provided
on both sides of the upper side and the lower side with the steel plate H of the cooling
system 1 interposed therebetween.
20 [0025]
The cooling system 1 includes a plurality of constraining roll pairs 10, upper
cooling apparatuses 11, and lower cooling apparatuses 12, and a control unit 5.
The plurality of constraining roll pairs 10 includes constraining rolls 10a
arranged above the steel plate H, and the conveying rolls 10b arranged below the steel
25 plate. The constraining rolls 10a and the conveying rolls 10b are lined up in the
12
horizontal direction in the plate passing direction of the steel plate H, and allow the steel
plate H to pass restrictively therebetween. Each constraining roll pair 10 is constituted
by two constraining rolls arranged up and down. The steel plate H is conveyed in a
state where the steel plate is sandwiched between the upper and lower constraining rolls.
5 In addition, the lower constraining roll may be referred to as a conveying roll.
Additionally, the constraining rolls 10a and the conveying rolls 10b sandwich
the steel plate H.
[0026]
An upper cooling apparatus 11 that cools the upper surface side of the steel plate
10 H and a lower cooling apparatus 12 that cools the lower surface side of the steel plate H
are arranged, respectively, between adjacent constraining roll pairs 10 and 10.
Specifically, the upper cooling apparatus 11 and the lower cooling apparatus 12 are
arranged so as to be opposed to each other with the steel plate H interposed therebetween.
This configuration enables the cooling system 1 to cool the upper and lower surfaces of
15 the steel plate H. Additionally, the upper cooling apparatus 11 and the lower cooling
apparatus 12 have a plurality of spray nozzle rows 21. The spray nozzle rows 21 are
arranged in the plate passing direction of the steel plate H, and each of the spray nozzle
rows 21 has a plurality of identical spray nozzles 20 lined up in the width direction of the
steel plate H.
20 [0027]
The lower cooling apparatus 12 is provided with a plurality of spray nozzles
arranged side by side in the plate passing direction and width direction of the steel plate
H, for example, full cone spray nozzles (not shown). Although the full cone nozzles of
the lower cooling apparatus 12 are not shown, these nozzles have a slightly larger amount
25 of ejected water than the full cone spray nozzles of the upper cooling apparatus 11 shown
13
in FIG 2. Cooling water is sprayed onto the steel plate H from the full cone spray
nozzles, and the steel plate H is cooled by a water jet stream of the cooling water from
the lower surface side.
[0028]
5 The upper cooling apparatus 11, as shown in FIGS. 2 and 3, has a plurality of
spray nozzles that sprays cooling water onto the upper surface of the steel plate H, that is,
the full cone spray nozzles 20 in the present embodiment. The full cone spray nozzle 20,
as shown in FIG 4, can spray a conic water jet stream.
[0029]
10 A plurality of full cone spray nozzles 20, as shown in FIGS. 2 and 3, forms
nozzle rows in the width direction of the steel plate H, and a plurality of the nozzle rows
is lined up in the plate passing direction. For example, in FIGS. 2 and 3, the spray
nozzle rows 21 arranged side by side in nine rows are configured. In each of the spray
nozzle rows 21a to 21 i, the plurality of spray nozzles 20 is arranged side by side in the
15 width direction of the steel plate H. That is, the plurality of full cone nozzles 20 is
alternately arranged in a horizontal cross-sectional view. This configuration allows the
cooling water sprayed from the full cone spray nozzles 20 to be sprayed onto the upper
surface of the steel plate H.
[0030]
20 The nine spray nozzle rows 21a to 21i, as shown in FIGS. 2 and 3, are classified
into the spray nozzle rows 21a to 21c that are respective spray nozzle rows 21 located on
the relative upstream side and the spray nozzle rows 2Id to 21i that are respective spray
nozzle rows located on the relative downstream side, when viewed in the plate passing
direction. Specifically, the spray nozzle rows are grouped into two nozzle row group 22
25 and nozzle row groups 23 that are arranged in the plate passing direction of the steel plate
4
H. Hereinafter, a nozzle row group arranged on the upstream side (the upstream side of
the steel plate H) of the steel plate H is referred to as an upstream spray nozzle row group
22, and a nozzle row group arranged on the downstream side (the downstream side of the
steel plate H) of the steel plate H is referred to as a downstream spray nozzle row group
5 23. As described above, the upstream spray nozzle row group 22 is constituted by, for example, three spray nozzle rows 21a to 21c, and the downstream spray nozzle row
group 23 is constituted by, for example six spray nozzle rows 21d to 21i. In addition, a
method of setting the number of rows of the spray nozzle rows 21 a to 21 i in the upstream
spray nozzle row group 22 and the downstream spray nozzle row group 23 will be
10 described below. Additionally, the arrangement position of the upstream spray nozzle row group 22 will be described below.
[0031]
One end portion of a supply pipe 24 that supplies cooling water to each of the
full cone spray nozzles 20 is connected to the full cone spray nozzle 20. The supply
15 pipe 24 extends vertically upward from the full cone spray nozzle 20, and the other end
portion of the supply pipe 24 is arranged within a nozzle box 30 that can store cooling
water.
[0032]
The inside of the nozzle box 30 is partitioned into two storage chambers 31 and
20 32. The supply pipes 24 of the full cone spray nozzles 20 of the upstream spray nozzle
row group 22 are accommodated in the upstream storage chamber 31 arranged on the
upstream side of the steel plate H. Additionally, the supply pipes 24 of the full cone
spray nozzles 20 of the downstream spray nozzle row group 23 is accommodated in the
downstream storage chamber 32 arranged on the downstream side of the steel plate H.
25 Cooling water is always stored up to the positions of the other end portions of the supply
pipes 24 in each of the storage chambers 31 and 32. Thereby, if cooling water is
supplied from a header 40 to be described below to the storage chambers 31 and 32, the
cooling water is supplied to the full cone spray nozzles 20 via the supply pipes 24.
Accordingly, the reaction of an upper cooling section 11 becomes rapid, and the steel
5 plate H can be suitably cooled. Additionally, even in a case when cooling is not
performed, damage caused by the heating of the nozzle box 30 (from the hot steel plate)
can be prevented by the cooling water stored in the respective storage chambers 31 and
32.
[0033]
10 A supply header 40 that supplies cooling water to the nozzle box 30 (the
upstream spray nozzle row group 22 and the downstream spray nozzle row group 23) is
arranged above (on the upstream side of) the nozzle box 30. A flow rate regulating
valve 41 is provided above (on the upstream side of) the supply header 40. The opening
or closing of the flow rate regulating valve 41 allows cooling water to circulate through
15 the inside of the supply header 40, and the flow rate of the cooling water to be supplied to
the inside of the supply header 40 to be adjusted (controlled). Piping 42 communicated
with the supply header 40 is connected to the upstream storage chamber 31. An on-off
control valve (first control valve) 43 is interposed in the piping 42, and the permission or
prohibition (on or off, or opening or closing of the valve) of supply of the cooling water
20 from the supply header 40 to the upstream storage chamber 31 (upstream spray nozzle
row group 22) is controlled by the on-off control valve 43. Similarly, piping 44
communicating with the supply header 40 is also connected to the downstream storage
i
chamber 32. An on-off control valve (second control valve) 45 is interposed in the ;
piping 44, and the permission or prohibition (on or off, or opening or closing of the
25 valve) of supply of the cooling water from the supply header 40 to the downstream
16
storage chamber 32 (downstream spray nozzle row group 23) is controlled by the on-off
control valve 45.
Additionally, the flow rate regulating valve 41, the on-off control valve 43, and j
the on-off control valve 45 are connected to the control unit 5. The control unit 5
5 controls the cooling water sprayed toward the steel plate H from the plurality of spray
nozzle rows 21. j
[0034] |
Additionally, as shown in FIG 2, it is preferable that the mutually adjacent
intervals a are the same in the plate passing direction of the respective spray nozzle rows
10 21 that belong to the upstream spray nozzle row group 22. It is preferable that the
mutually adjacent intervals b are the same in the plate passing direction of the respective
the spray nozzle rows 21 that belong to the downstream spray nozzle row group 23.
Moreover, it is preferable that the adjacent interval c between the spray nozzle rows 21c
arranged closest to the downstream spray nozzle row group 23 side among the respective
15 the spray nozzle rows 21 that belong to the upstream spray nozzle row group 22 and the
spray nozzle row 2Id arranged closest to the upstream spray nozzle row group 22 side j
among the respective spray nozzle rows 21 that belong to the downstream spray nozzle
row group 23 is equal to the adjacent interval a and the adjacent interval b. That is, it is
preferable that all the adjacent intervals of the respective spray nozzle rows 21 in the
20 plate passing direction are the same.
Moreover, it is preferable that all the mutually adjacent intervals of the
respective spray nozzle rows 21 in the width direction of the steel plate are the same.
[0035]
In the upper cooling apparatus 11 of the above configuration, first, a required
25 cooling water amount is determined from a cooling rate or cooling stop temperature
% 17
required for the steel plate H. The flow rate regulating valve 41 is controlled by the
control unit 5 and the flow rate of the cooling water to be supplied to the supply header
40 is regulated so that the cooling water of the cooling water amount is supplied. At
this time, it is determined in the control unit 5 whether both the on-off control valves 43
5 and 45 are opened or only the on-off control valve 43 is opened, as described below. At
this time, in a case where the required cooling water amount is larger than the maximum
water amount of the upstream spray nozzle row group 22, both the on-off control valves
43 and 45 are opened by the control unit 5. On the other hand, in a case where the
required cooling water amount is smaller than the maximum water amount of the
10 upstream spray nozzle row group 22, only the on-off control valve 43 is opened by the
control unit 5. Then, cooling water is supplied to the upstream storage chamber 31 from
the supply header 40, for example by opening the on-off control valve 43. The cooling
water within the upstream storage chamber 31 is sprayed onto the steel plate H via the
supply pipes 24 of the upstream spray nozzle row group 22, and the full cone spray
15 nozzles 20. Similarly, cooling water is sprayed onto the steel plate H via the
downstream storage chamber 32, the supply pipes 24 of the downstream spray nozzle
row group 23, and the full cone spray nozzles 20 from the supply header 40, for example
by opening the on-off control valve 45. In this way, in the upper cooling apparatus 11,
spraying of cooling water is controlled in every nozzle row group 22 or 23.
20 [0036]
Next, a method of setting the numbers of rows of the spray nozzle rows 21a to
21i in the nozzle row groups 22 and 23 described above, and the arrangement position of
the upstream spray nozzle row group 22 will be described above together with a method
of cooling the steel plate using the upper cooling apparatus 11.
25 [0037]
18
In setting the numbers of rows of the spray nozzle rows 21a to 21 i, and the
arrangement position of the upstream spray nozzle row group 22, first, the characteristics
of a full cone spray nozzle 20 to be used in an embodiment to be described below will be 5
described using this full cone spray nozzle as an example. The rated maximum load
5 pressure of the full cone nozzle 20 is 0.3 MPa. The spray angle a of a water jet stream from the full cone spray nozzle 20 I
shown in FIG 4 depends on the nozzle load pressure of the full cone spray nozzle 20. [
i
The results that the inventors have investigated regarding this point are shown in FIG 5. I
The horizontal axis of FIG 5 represents the nozzle load pressure, and the vertical axis |
10 represents the change rate of the spray angle. Referring to FIG. 5, it can be seen that the j
change rate of the spray angle of the full cone spray nozzle 20 decreases abruptly when
the nozzle load pressure is equal to or lower than about 0.04 MPa (dotted line in FIG 5).
This shows that, in a case where the nozzle load pressure is equal to or lower than 0.04
MPa, the area of a collision portion of a water jet stream onto the steel plate H from the
15 full cone spray nozzle 20, that is, a so-called spray pattern cannot be secured.
Accordingly, in order to suitably cool the steel plate H, it can be seen that the nozzle load
pressure of the full cone spray nozzle 20 is required to be equal to or higher than 0.04
MPa. In addition, in the present embodiment, although the nozzle load pressure is set to
be equal to or higher than 0.04 MPa, this is just an example.
20 [0038]
Additionally, the inventors have investigated the cooling water amount of the
full cone spray nozzle 20 that is required to secure a nozzle load pressure of 0.04 MPa or
higher, that is, to secure the spray pattern. The results are shown in FIG. 6. The
horizontal axis of FIG 6 represents the nozzle load pressure, and the vertical axis
25 represents the cooling water amount of the full cone spray nozzle 20. Referring to FIG. j
19 |
6, as for the range of the cooling water amount that secures the spray pattern, it can be seen that the range of the ratio of the maximum water amount and minimum water [
amount of the full cone spray nozzle 20 is within a range of about 3:1. |
[0039]
5 Here, the cooling of the steel plate H using the upper cooling apparatus 11 of the
cooling system 1 will be described. FIG 7 shows the relationship between the nozzle
load pressure of the full cone spray nozzle 20, and the water amount density of the
cooling water supplied from the upper cooling apparatus 11. In addition, the water
amount density represents the cooling water amount per unit area of the cooling water
10 sprayed onto the steel plate H between the constraining roll pair 10a and 10b arranged
with the steel plate H interposed therebetween. Accordingly, although the water amount
density or the cooling water amount may be described hereinbelow, both have the same
meaning.
[0040]
15 As described above, in the hot rolling, the cooling capacity required for the
cooling system 1, that is, the required cooling water amount, (water amount density)
differs depending on the type, usage, or the like of the steel plate H. For example, in a
case where the required cooling water amount is larger than the maximum water amount
of the upstream spray nozzle row group 22 (the range of an upper solid line in the graph
20 of FIG 7), in order to secure this high water amount density, cooling water is sprayed
onto the upper surface of the steel plate H from both the upstream spray nozzle row
group 22 and the downstream spray nozzle row group 23, for example, as shown in FIG
8. In this case, since the cooling water amount is larger than the maximum water
amount of the upstream spray nozzle row group 22, the water on the surface 50 that
25 accumulates on the steel plate H spreads to the entire upper surface of the steel plate H
i
* 20
between the constraining roll pairs 10 and 10. Specifically, since the water on the
surface 50 and the cooling water sprayed from the upstream spray nozzle row group 22
and the downstream spray nozzle row group 23 are forcedly stirred on the whole surface
of the steel plate H, the steel plate H is uniformly cooled at least in the width direction of I
5 the steel plate H. Accordingly, in order to avoid the influence of the water on the
surface 50, it is necessary to secure the spray pattern of each full cone spray nozzle 20. j
That is, as described above, the nozzle load pressure of the full cone spray nozzle 20 is
required to be equal to or higher than 0.04 MPa. In the graph of FIG 7, in the range of
the upper solid line, this nozzle load pressure can be secured and the steel plate H can be
10 suitably cooled.
[0041] j
On the other hand, if the required cooling water amount (water amount density) j
decreases as shown in FIG 7, the nozzle load pressure of the full cone spray nozzle 20 I
also decreases. For example, in a case where the required water amount density is equal j
15 to or lower than about 0.55 m /m /min in FIG 7, that is, lower than the maximum water j
amount of the upstream spray nozzle row group 22, if the cooling water is supplied from ]
both the upstream spray nozzle row group 22 and the downstream spray nozzle row
group 23, the nozzle load pressure of 0.04 MPa cannot be secured in each of the full cone
spray nozzles 20. 20 [0042]
Therefore, cooling water is sprayed onto the upper surface of the steel plate H
only from the upstream spray nozzle row group 22, and the spraying of the cooling water 1
from the downstream spray nozzle row group 23 is stopped. Here, in a case where the
required water amount density is a water amount density that is equal to or lower than
25 about 0.55 m /m /min (the range of the lower solid line in the graph of FIG 7), that is,
21 I
lower than the maximum water amount of the upstream spray nozzle row group 22, as
shown in FIG 9, the water on the surface 50 on the steel plate H becomes a small amount, and the water on the surface 50 flows in the plate passing direction of the steel plate H, I
that is, toward the downstream side of the steel plate H, with the movement of the steel
5 plate H. Accordingly, the spraying of the cooling water from the downstream spray
nozzle row group 23 is stopped as described above. Thereby, as shown in the graph of
FIG. 7, the upper solid line shifts to the lower solid line, and the nozzle load pressure of
the full cone spray nozzle 20 in the upstream spray nozzle row group 22 rises abruptly.
Accordingly, the spray pattern of the full cone spray nozzle 20 can be secured, and the
10 steel plate H can be suitably cooled.
[0043]
In a case where the spraying of the cooling water from the downstream spray
nozzle row group 23 is stopped, as in the present embodiment, it is most preferable that
the ratio of the number (nine rows) of rows of all the spray nozzle rows 21a to 21i and
15 the number (three rows) of rows of the spray nozzle rows 21a to 21c of the upstream
spray nozzle row group 22 be the ratio of the maximum water amount and minimum j
water amount of the full cone spray nozzle 20, that is, the above-described 3:1. For
example, in a case where the number of rows of the spray nozzle rows 21 of the upstream
spray nozzle row group 22 is equal to or higher than four, the nozzle load pressure of
20 each full cone spray nozzle 20 becomes small compared to a case where the number of
rows of the upstream spray nozzle row group 22 is three. Then, in a case where the
required cooling water amount has further decreased, and the number of rows of the
upstream spray nozzle row group 22 is three, the spray pattern can be secured.
However, in a case where the number of rows of the upstream spray nozzle row group 22
25 is equal to or higher than four, a case where the spray pattern cannot be secured occurs.
w 22
That is, the range of the water amount density in which the spray pattern can be secured
and the steel plate H can be suitably cooled in a case where the number of rows of the
upstream spray nozzle row group 22 is equal to or higher than four becomes narrow
compared to the range of the water amount density in a case where the number of rows of
5 the upstream spray nozzle row group 22 is three. Incidentally, in the present
embodiment, the ratio of the maximum water amount density and minimum water
amount density, that is, the cooling capacity control range, of controllable cooling water
becomes a wide range of 9:1. On the other hand, if the number of rows of the upstream
spray nozzle row group 22 becomes equal to or lower than two, the amount of the
10 cooling water sprayed from each full cone spray nozzle 20 exceeds the maximum water
amount, and the required water amount density cannot be secured. Accordingly, as
described above, it is most preferable that the ratio of the number of rows of all the spray
nozzle rows 21a to 2 li and the number of rows of the spray nozzle rows 21a to 21c of the
upstream spray nozzle row group 22 be an integer ratio that is the same as or approaches
15 the ratio of the maximum water amount and minimum water amount of the full cone
spray nozzle 20.
[0044]
In addition, in the present embodiment, the ratio of the maximum water amount
and minimum water amount of the full cone spray nozzle 20 is 3:1. Thus, the ratio of
20 the number of rows of all the spray nozzle rows 21 a to 21 i and the number of rows of the
spray nozzle rows 21a to 21c of the upstream spray nozzle row group 22 is set to 3:1. However, the ratio of the numbers of the spray nozzle rows is not limited to this. If the
ratio of the numbers of the spray nozzle rows is the ratio of the maximum water amount
and minimum water amount of a spray nozzle as described above, the ratio of the
25 numbers of the spray nozzle rows can be set to various values. For example, in a case
23 I
where the spray nozzles to be used for the cooling system is changed and the ratio of the I
maximum water amount and minimum water amount is 7:3, the ratio of the number
(seven rows) of rows of all the spray nozzle rows and the number (three rows) of rows of
the spray nozzle rows of the upstream spray nozzle row group is also set to 7:3.
5 [0045] I
Additionally, in a case where the ratio of the maximum water amount and [
minimum water amount of the full cone spray nozzle 20 is not expressed by an integer ratio, the ratio of the number of rows of all the spray nozzle rows 21a to 21i and the
number of rows of the spray nozzle rows 21a to 21c of the upstream spray nozzle row
10 group 22 may be set to an integer ratio approaching the ratio of the maximum water
amount and minimum water amount of the full cone spray nozzle 20. Specifically, the
ratio of the maximum water amount in a case where the minimum water amount is set to
1 is set to an integer by rounding off to the closest integer. For example, in a case where j
the ratio of the maximum water amount and minimum water amount of the full cone
15 spray nozzle is 1:3.1, the ratio can be 1:3 by rounding off 3.1 to the closest integer. The
integer ratio of the maximum water amount and minimum water amount of the full cone spray nozzle 20 obtained in this way may be set to an integer ratio to approach the above. i
It is not preferable that an uncontrollable water amount density range be
between the maximum water amount density and the minimum water amount density.
20 Therefore, it is preferable to approximate the ratio of the number of rows of all the spray
nozzle rows and the number of rows of the spray nozzle rows of the upstream spray
nozzle row group 22 so as to become smaller than the ratio of the maximum water
amount and minimum water amount of a spray nozzle.
In the present invention, it is not necessary to provide an upper limit to the ratio
25 of the numbers of the spray nozzle rows. However, even if the nozzle load pressure is
raised to about 0.7 MPa, the ratio of the maximum water amount and the minimum water
amount is about four, and may be equal to or lower than four. If needed, the upper limit
may be 3.5, 3, or 2.5.
[0046]
5 Additionally, as described above with reference to FIG 9, the water on the
surface 50 may flow to and accumulate on the downstream side of the steel plate H
depending on a required cooling water amount. In this case, it is preferable that the
upstream spray nozzle row group 22 be arranged so that the cooling water sprayed from
the upstream spray nozzle row group 22 does not interfere with the water on the surface
10 50. Specifically, when a maximum spraying amount is sprayed from the upstream spray
nozzle row group 22, it is preferable that the upstream spray nozzle row group 22 be
arranged so that cooling water is sprayed from the upstream spray nozzle row group 22
toward a position of the upstream side in the plate passing direction not overlapped with
the region of the water on the surface 50 that accumulates on the steel plate H. j
15 [0047] j
Moreover, the inventors keenly studied the range over which the water on the I
surface 50 is present on the steel plate H in a case where cooling water is sprayed only f
from the upstream spray nozzle row group 22. Specifically, first, the cooling water of
the water amount density W of the maximum water amount of the upstream spray nozzle 20 row group 22 was sprayed from the upper cooling apparatus H to the steel plate H in a f
state where the steel plate H is made stationary, and the height he of the water on the f
surface at the center in the plate width direction was derived through experiments. Next, in a case where the cooling water of the same water amount density W as the steel plate
H passed at a plate passing speed Ls was sprayed, an experiment was performed
25 regarding the range over which cooling water spreads on the steel plate H as the water on
i
I
I
f
I
25 |
the surface 50 as shows in FIG 9. Then, the height distribution of the water on the
surface 50 on the steel plate H was assumed to be secondary distribution in the width |
direction. As a result, the inventors obtained the knowledge that the range Xo where the j
water on the surface 50 shown in FIG 9 is present is expressed by the following Formula ;
5 (1). In addition, the range Xo represents the distance from the center of the downstream
constraining roll pair 10 of the steel plate H to the end portion of the water on the surface
50. Additionally, the water on the surface height he in Formula (1) represents the height
of the water on the surface 50 at the center of the steel plate H in the width direction, and
is expressed by the following Formula (2).
10 [0048]
[Formula 1]
.. 29.4 xhcxS ,., N
^ o = ~2 • • ' • ( !)
Ls
[0049]
Here, Xo: Horizontal range of water on the surface 50 (m), he: Height (m) of
15 water on the surface 50 at center in plate width direction in a case where steel plate H is j
in a stationary state, S: Distance m between centers of constraining roll pairs 10 and 10,
Ls: Plate passing speed (m/min) of steel plate H
Additionally, in the above Formula (1), "29.4" is a constant having a dimension
of (m/min ).
20 [0050]
[Formula 2]
he = 0.04 x (W x B)i • • . . (2)
[0051]
'i
i
• 26
Here, W: Water amount density (m3/m2/min) of cooling water sprayed from
upper cooling apparatus 11, B: Width (m) of steel plate H.
Additionally, in the above Formula (2), "0.04" is a constant having a dimension
of(m(-1/3)/min(2/3)). |
5 [0052]
As described above, the range Xo where the water on the surface 50 is present on j
the steel plate H is calculated by the above Formula (1). In addition, the position of an
upstream end portion of the range Xo where the water on the surface 50, as shown in FIG
9, is almost the same as the position of an upstream end portion of the downstream spray
10 nozzle row group 23. The upstream spray nozzle row group 22 is arranged at a position
where a water jet stream of the cooling water sprayed from the downstream spray nozzle j
row 21c does not interfere with the water on the surface 50, that is, at a position where a
downstream end portion of the water jet stream is apart from the center of downstream
constraining roll pair 10 by the range Xo or higher. Thereby, since the upstream spray
15 nozzle row group 22 sprays cooling water to a place with almost no water on the surface
50, the region of the steel plate H that the sprayed cooling water hits is uniformly cooled. !
j
That is, since the direction in which the water on the surface 50 flows is the same as the j
plate passing direction of the steel plate H, the water on the surface 50 is seldom stirred. j
I
By suppressing stirring of the water on the surface 50 in this way, the steel plate H can be !
20 uniformly cooled. j
[0053]
According to the above embodiment, the spraying of the cooling water onto the
upper surface of the steel plate H is controlled in each nozzle row group 22 or 23. For j
example, in a case where the required cooling capacity is high, that is, in a case where the 25 required cooling water amount is smaller than the maximum water amount of the
W 27
upstream spray nozzle row group 22 (the range of the upper solid line in the graph of FIG.
7), the cooling water of which the flow rate has been controlled by the flow rate
regulating valve 41 is first supplied to the supply header 40. Then, both the on-off
control valves 43 and 45 are opened, and cooling water is sprayed onto the upper surface
5 of the steel plate H from all the nozzle row groups 22 and 23. In this case, since the
nozzle load pressure of the full cone spray nozzle 20 is high, even if the water on the
surface 50 accumulates on the steel plate H, the spray pattern of each full cone spray
nozzle 20 can be secured and the water on the surface 50 is forcibly stirred as a whole.
Thus, the steel plate H can be uniformly cooled. Accordingly, the steel plate H can be
10 uniformly cooled to a predetermined temperature.
[0054]
On the other hand, for example, in a case where the required cooling capacity is
low, that is, in a case where the required cooling water amount is smaller than the
maximum water amount of the upstream spray nozzle row group 22 (the range of the
15 lower solid line in the graph of FIG 7), the flow rate of cooling water is first controlled
by the flow rate regulating valve 41, and this cooling water is supplied to the supply
header 40. Then, only the on-off control valve 43 is opened, for example cooling water
is sprayed onto the upper surface of the steel plate H only from the upstream spray nozzle
row group 22 of the steel plate H, and the spraying of the cooling water from the
20 downstream spray nozzle row group 23 of the steel plate is stopped. In this case, with
the nozzle load pressure of the full cone spray nozzle 20 high and the spray pattern
maintained, the amount of cooling water sprayed onto the steel plate H can be set to a
predetermined water amount. Additionally, the water on the surface 50 on the steel
plate H becomes a small amount, and the water on the surface 50 flows in the plate
25 passing direction of the steel plate H, that is, to the downstream side of the steel plate H,
28 J
with the movement of the steel plate H. For this reason, the cooling water sprayed to f
the upstream side of the steel plate H can cool the steel plate H uniformly without being j
I
influenced by the water on the surface 50. Accordingly, the steel plate H can be j
i
uniformly cooled to a predetermined temperature. According to the present 5 embodiment as described above, the steel plate H can be uniformly cooled to a *
predetermined temperature while controlling the cooling capacity over a broad range. j
[0055]
f
Here, disadvantages in a case where cooling water is sprayed only from the
downstream spray nozzle row group 23 will be described. [
10 In this case, as shown in FIG 10, the water on the surface 50 flows to the i
upstream side from a spraying region. Since the direction in which the water on the i
surface 50 flows and the plate passing direction of the steel plate H are reverse, an i
irregular flow occurs in the water on the surface 50, and cooling of the steel plate H
becomes uneven in the width direction or the longitudinal direction on the upstream side
15 of the spraying region. Accordingly, it is not preferable to spray cooling water only
from the downstream spray nozzle row group 23.
[0056] '
Next, advantages in a case where the same full cone spray nozzles 20 are
arranged in all the spray nozzle rows 21a to 21i will be described. In this case, the
20 cooling capacities of all the full cone spray nozzles 20 are the same in the upper cooling
apparatus 11. As described above, in a case where spray nozzles different cooling
capacities are used, cooling water becomes uneven with respect to the steel plate H.
However, in the present embodiment, cooling water does not become uneven with
respect to the steel plate H because the cooling water sprayed from the full cone spray
25 nozzles 20 can be kept from affecting each other. For this reason, spraying of cooling
water can be controlled in each of the downstream spray nozzle row group 23 and the
upstream spray nozzle row group 22 to cope with a case where the required cooling
capacity is high, a case where low or even a case at the boundary of the cooling capacity.
Accordingly, the cooling capacity control range can be selected over a broad range. In
5 addition, since the cooling capacities of all the full cone spray nozzles 20 are the same, there is also an effect that the control of the full cone spray nozzles 20 when cooling the
steel plate H becomes easy. [0057]
Moreover, the ratio of the number of rows of all the spray nozzle rows 21 a to 21 i
10 and the number of rows of the spray nozzle rows 21ato21cof the upstream spray nozzle i
row group 22 is set to the ratio of the maximum water amount and minimum water I
amount of each full cone spray nozzle 20. For this reason, in a case where the required
cooling capacity has decreased, as described above, the spraying of the cooling water
from the downstream spray nozzle row group 23 can be stopped at a suitable timing.
15 Accordingly, the cooling capacity control range can be maximized, while securing the f
required cooling capacity. [
[0058] !
Additionally, since the upstream spray nozzle row group 22 is arranged at a
position where a water jet stream of the cooling water sprayed from the upstream spray i
20 nozzle row group 22 does not interfere with the water on the surface 50, the cooling I
water sprayed from the spray nozzle rows 21c of the downstream is not influenced by the {
water on the surface 50. Moreover, the spray pattern of each full cone spray nozzle 20
can be secured as described above. Accordingly, even in a case where the required f
i
cooling capacity is low, the steel plate H can be suitably cooled.
25 [0059] I
i
I
1
1
I I
30 |
Although the steel plate H can be uniformly cooled in the present embodiment
as described above, the inventors have verified this effect. Specifically, in a case where f
the required cooling water amount is smaller than the maximum water amount of the
upstream spray nozzle row group 22, as shown in FIG 9, cooling water was sprayed onto
5 the steel plate H only from the upstream spray nozzle row group 22. >•
[0060] j.
Then, the results when the width-direction distribution of the cooling rate from 750 to 600°C in a case where the steel plate H was cooled to 100°C or lower was
measured are shown in FIG 11. The horizontal axis of FIG 11 represents the positions
10 of the steel plate H in the width direction, and the vertical axis represents the cooling I
i
I
rates of the steel plate H in the respective positions in the width direction. Referring to I
FIG 11, it is confirmed that the cooling rates become almost uniform in the width f
I'
direction of the steel plate H, and the steel plate H can be uniformly cooled. I
I
[0061] j
15 [Second Embodiment]
Next, a cooling system of a second embodiment of the present invention will be f
described. |
I
|
FIGS. 12 to 15 show a second embodiment, and show a steel plate cooling S
system. Hereinafter, steel materials are thick plates, and members and apparatuses I
f
20 above a steel plate will be described. In the following description, the description of the f
same members as those of the first embodiment is omitted. f
Additionally, the second embodiment is different from the first embodiment in ;
that water supply headers are provided in the upstream spray nozzle row group and '
downstream spray nozzle row group, respectively, and that the flow rate regulating valve f
25 is provided in each water supply header.
j
I
* 31
[0062]
A steel plate cooling system 100 includes an upper cooling apparatus 111 and a
lower cooling apparatus 151. The upper cooling apparatus 111, as shown in FIG 12,
includes a small-flow-rate cooling unit (upstream spray nozzle row group) 110 and a
5 large-flow-rate nozzle cooling unit (downstream spray nozzle row group) 130. The
small-flow-rate cooling unit 110 and the large-flow-rate nozzle cooling unit 130 are
arranged above the steel plate H.
The small-flow-rate cooling unit 110 includes a small-flow-rate water supply
header (first water supply header) 117. The small-flow-rate water supply header 117
10 supplies cooling water to the small-flow-rate cooling unit 110. Additionally, the I
large-flow-rate nozzle cooling unit 130 includes a large-flow-rate water supply header {
(second supply header) 137. The large-flow-rate water supply header 137 supplies l
cooling water to the large-flow-rate nozzle cooling unit 130.
Additionally, the steel plate cooling system 100 includes a flow rate regulating I
15 valve (first flow rate regulating valve) 114 that adjusts the flow rate of the cooling water }
to be supplied to the small-flow-rate water supply header 117, and a flow rate regulating
valve (second flow rate regulating valve) 134 that adjusts the flow rate of the cooling
water to be supplied to the large-flow-rate water supply header 137.
Moreover, the flow rate regulating valves 114 and 134 are connected to a flow
20 rate adjusting unit (control unit) 149. Moreover, a channel switching three-way valve
115 or 135 that is one of on-off control valves is connected to the flow rate adjusting unit
149. I
The flow rate adjusting unit 149 controls the opening or closing of the flow rate
regulating valves 114 and 134 and the channel switching three-way valves 115 and 135,
25 and controls the cooling water made to be sprayed toward the steel plate H from a
%
32
plurality of cooling water spray nozzles 126.
[0063]
The small-flow-rate water supply header 117 is connected to a cooling water
tank (not shown) via a small-flow-rate cooling water supply pipe 112. The flow rate
5 regulating valve 114 and the channel switching three-way valve 115 are attached to the
small-flow-rate cooling water supply pipe 112. One outlet of the channel switching
three-way valve 115 is connected to the small-flow-rate water supply header 117 via the
small-flow-rate cooling water supply pipe 112. Hereinafter, switching of this direction
is referred to as opening. Additionally, the outer outlet of the channel switching
10 three-way valve 115 is connected to the cooling water tank (not shown) via a return pipe
(not shown). Hereinafter, switching of this direction is referred to as closing.
Similarly, the large-flow-rate nozzle cooling unit 130 also includes the
large-flow-rate cooling water supply pipe 132, the flow rate regulating valve 134, and the
channel switching three-way valve 135.
15 [0064]
The flow rate regulating valve 114 of the small-flow-rate cooling unit 110 and
the flow rate regulating valve 134 of the large-flow-rate nozzle cooling unit 130
preferably have degrees of opening that become a water supply amount density
proportional to the ratio of the number of cooling water spray nozzles of the
20 large-flow-rate nozzle cooling unit 130 to the number of cooling water spray nozzles of
the small-flow-rate cooling unit 110. Thereby, the amount of cooling water from the
cooling water spray nozzles 126 of the small-flow-rate cooling unit 110 and the amount [
of cooling water from cooling water spray nozzles 146 of the large-flow-rate nozzle
cooling unit 130 are uniformly maintained, so that the steel plate H can be uniformly
25 cooled.
33
[0065]
The small-flow-rate cooling unit 110 includes a small-flow-rate nozzle header
122, and the large-flow-rate nozzle cooling unit 130 includes a large-flow-rate cooling
water nozzle header 142. As shown in FIG 13, small-flow-rate nozzle water supply
5 pipes 119 are connected to the small-flow-rate nozzle header 122, and large-flow-rate
nozzle water supply pipes 139 are connected to the large-flow-rate nozzle header 142.
Moreover, the small-flow-rate cooling water spray nozzles 126 are attached to the
small-flow-rate nozzle header 122, and the large-flow-rate cooling water spray nozzles
146 are attached to the large-flow-rate nozzle header 142.
10 [0066]
The small-flow-rate cooling water spray nozzles 126 and the large-flow-rate
cooling water spray nozzles 146 are the same. Additionally, the intervals of the
small-flow-rate cooling water spray nozzles 126 and the large-flow-rate cooling water
spray nozzles 146 in the plate passing direction are equal. Moreover, the intervals of
15 the cooling water spray nozzles 126 and 146 of the adjacent small-flow-rate cooling unit
110 and large-flow-rate nozzle cooling unit 130 in the plate passing direction are also
equal to the intervals of the other cooling water spray nozzles 126 and 146 in the plate
passing direction. Thereby, deviation decreases in the accumulated amount of the water
on the surface, and the steel plate is uniformly cooled. 20 [0067]
As shown in FIG 13, the small-flow-rate cooling water spray nozzles 126
penetrates through a bottom plate 124 of the small-flow-rate nozzle header 122, cooling
water inlets 127 of upper ends thereof are located near a top plate 123, and jetting ports
28 of lower ends thereof protrude downward from the bottom plate 124. The
25 large-flow-rate nozzle header 142 has the same structure as the small-flow-rate nozzle
34
header 122, and the large-flow-rate cooling water spray nozzles 146 have the same
structure as the small-flow-rate cooling water spray nozzles 126.
[0068]
It is preferable that the interval g between the top plate 123 of the
5 small-flow-rate nozzle header 122 and the cooling water inlets 127 of the small-flow-rate j
cooling water spray nozzles 126 and the interval g between the top plate 143 of the
large-flow-rate nozzle header 142 and cooling water inlets 147 of the large-flow-rate
cooling water spray nozzles 146 be set to 3 to 8 mm. If the interval g is less than 3 mm,
the pressures applied to the cooling water inlets do not become equal, and water is apt to
10 come out in the cooling water spray nozzles nearest to the nozzle water supply pipes 119
and 139. Thereby, the difference between the amounts of water sprayed from the
respective spray nozzles 126 and 146 may occur. Additionally, if the interval g exceeds
8 mm, excessive time is taken until the small-flow-rate nozzle header 122 and the
large-flow-rate nozzle header 142 are filled with water after water filling begins.
15 Moreover, if the interval g exceeds 8 mm, when the water filling from the cooling water j
spray nozzles 126 and 146 is stopped, water will drip from the cooling water spray
nozzles 126 and 146 until all the water accumulated between the cooling water inlets 127 I
and 147 and the top plates 123 and 142 of the headers is exhausted.
Additionally, a small-flow-rate cooling unit 150 and a large-flow-rate nozzle J
20 cooling unit 170 below the steel plate H that are the same as the small-flow-rate cooling
unit 110 and the large-flow-rate nozzle cooling unit 130 are arranged above the steel
plate H. In the small-flow-rate cooling unit 150 and the large-flow-rate nozzle cooling
unit 170, the intervals g are respectively the interval g between a bottom plate 164 of a
small-flow-rate nozzle header 162 and cooling water inlets 167 of small-flow-rate
25 cooling water spray nozzles 166 and the interval g between a bottom plate 184 of a
35
large-flow-rate nozzle header 182 and cooling water inlets 187 of large-flow-rate cooling
water spray nozzles 186.
[0069]
FIG 14 schematically shows the arrangement of the small-flow-rate cooling
5 water spray nozzles 126 (166) and the large-flow-rate cooling water spray nozzles 146
(186). As shown in FIG. 14, a number of the small-flow-rate cooling water spray
nozzles 126 (166) and a number of the large-flow-rate cooling water spray nozzles 146
(186) are arranged at regular intervals, respectively, in the steel plate width direction and
the steel plate conveying direction. Additionally, the small-flow-rate cooling water
10 spray nozzles 126 (166) and the large-flow-rate cooling water spray nozzles 146 (186)
have the same nozzle diameter, and the number of the small-flow-rate cooling water
spray nozzles is smaller than the number of the large-flow-rate cooling water spray
nozzles.
[0070]
15 FIG 15 shows the relationship between the water supply amount density
(m3/m2/min) and the nozzle water supply pressure (MPa). •
[0071]
A spray pattern securing limit pressure is a nozzle water supply pressure (for
example, 30 kPa) of whether or not a predetermined spray pattern determined according
20 to the nozzle can be secured. In order to cool a hot steel plate uniformly, it is necessary
to set the nozzle water supply pressure to be equal to or higher than the spray pattern
securing limit pressure. For this reason, in the cooling of the steel plate (steel material)
H, a water supply amount density for obtaining a required cooling rate (determined
depending on the constituents of the steel material and the material quality to be secured)
25 is determined. This determines whether water is supplied to both the small-flow-rate
nozzle header 122 and the large-flow-rate nozzle header 142 or to any one of the headers,
using the flow rate adjusting unit 149, in a region in which the nozzle water supply
pressure is equal to or higher than the spray pattern securing limit pressure with reference
to the water supply amount density and FIG 15. j
5 [0072] |
Specifically, cooling water is supplied to both the small-flow-rate nozzle header
122 and the large-flow-rate nozzle header 142 if the determined water supply amount
density is within a range of b to c as shown in FIG 15, and cooling water is supplied only
to the small-flow-rate nozzle header 122 if the water supply amount density is within a
10 range of a to b. Additionally, the spraying water amount and fuel spraying pressure
from the respective nozzles via the small-flow-rate nozzle header 122 and the
large-flow-rate nozzle header 142 are adjusted by the flow rate regulating valves 114 and
134 so as to become constant.
[0073]
15 The steel plate cooling system 100, as shown in FIG 12, includes the flow rate
adjusting unit 149 on the steel plate upper surface side. The flow rate adjusting unit 149
controls the cooling water to be sprayed toward the steel plate H from the small-flow-rate
cooling water spray nozzles 126 and the large-flow-rate cooling water spray nozzles 146.
In the flow rate adjusting unit 149, a cooling rate is determined by, for example, a host
20 computer from the constituents of a target steel plate, mechanical properties (material
quality), or the like, and a zone water supply amount density is obtained from this
cooling rate and the plate thickness of the target steel plate. Moreover, in the flow rate
adjusting unit 149, a nozzle header (both the large-flow-rate water supply header 137 and
the small-flow-rate water supply header 117, or only the small-flow-rate water supply
25 header 117) to be used is determined from the zone water supply amount density and FIG
* 37
15.
[0074]
The zone water supply amount density obtained in this way, and the information
on a nozzle header to supply water are input to the flow rate adjusting unit 149. Here,
5 in a case where the nozzle header information relates to using both the large-flow-rate
water supply header 137 and the small-flow-rate water supply header 117, a water supply
amount density ratio is further input to the flow rate adjusting unit 149. Then, the flow
rate adjusting unit 149 input the valve opening signals of the flow rate regulating valves
114 and 134, and the signals for opening the channel switching three-way valves 115 and
10 135, on the basis of the input zone water supply amount density, nozzle header
information, and water supply amount density ratio. Additionally, in a case where the
nozzle header information relates to using only the large-flow-rate water supply header
137, the flow rate adjusting unit 149 closes the channel switching three-way valve 115,
and opens the channel switching three-way valve 135, and outputs the valve opening
15 signal of the flow rate regulating valve 134. Additionally, in a case where the nozzle
header information relates to using only the small-flow-rate water supply header 117, the
flow rate adjusting unit 149 closes the channel switching three-way valve 135, and opens
the channel switching three-way valve 115, and outputs the valve opening signal of the
flow rate regulating valve 114. Additionally, a flow rate adjusting unit 189 on the lower
20 surface side of the steel plate H (control unit) is also the same.
[0075]
Although the cooling units 110 and 130 (upper cooling apparatus 111) above the
steel plate have been described above, the cooling units 150 and 170 (lower cooling
apparatus 151) below the steel plate H also have the same structure as the upper cooling
25 apparatus. That is, a cooling water supply pipe 152, a water supply header 157, a
38
nozzle water supply pipe 159, the nozzle header 162, the cooling water spray nozzles 166,
and a cooling water supply pipe 172, a water supply header 177, a nozzle water supply
pipe 179, the nozzle header 182, and the cooling water spray nozzles 186 have the same
structure as the upper cooling apparatus 111 above the steel plate H. Additionally, the
5 flow rate regulating valves 154 and 174, the channel switching three-way valves 155 and
175, and the flow rate adjusting unit 189 also have the same structure as the upper
cooling apparatus 111 above the steel plate H.
[0076]
Here, an example of the manipulation and operation of the steel plate cooling
10 system 100 configured as described above will be described.
[0077]
Before the steel plate cooling system 100 receives a rolled hot steel plate H, the ;
zone water supply amount density (For example, 1.5 m /m /min) of a cooling zone where
the steel plate cooling system 100 is arranged, information on a nozzle header to supply
15 water (for example, the large-flow-rate water supply header 137 and the small-flow-rate
water supply header 117), and the water supply amount density ratio (for example, 2.0)
of the large-flow-rate nozzle cooling unit 130 to the small-flow-rate cooling unit 110 are I
input to the flow rate adjusting unit 189 above the steel plate H top from the host
computer. Thereby, the flow rate adjusting unit 149 determines the respective water
20 supply amount densities (For example, small-flow-rate cooling unit: 0.5 m /m /min, and
large-flow-rate nozzle cooling unit: 1.0 m /m /min) of the small-flow-rate cooling unit j
110 and the large-flow-rate nozzle cooling unit 130, determines the opening degrees of
the flow rate regulating valves 114 and 134 on the basis of the determined respective water supply amount densities, and outputs to the flow rate regulating valves 114 and 134
25 the opening degree information from which the above water supply amount densities are
39
obtained. The flow rate regulating valves 114 and 134 operate if this opening degree
information is input, and have opening degrees corresponding to the information.
Thereby, the cooling water of the small-flow-rate cooling water supply pipe 112 passes
sequentially through the small-flow-rate water supply header 117 and the small flow rate
5 nozzle water supply pipes 119, and flows into the small-flow-rate nozzle header 122.
Additionally, the cooling water of the large-flow-rate cooling water supply pipe 132,
similar to above, passes sequentially through the large-flow-rate water supply header 137
and the large-flow-rate nozzle water supply pipes 139, and flows into the large-flow-rate
nozzle header 142. The small-flow-rate nozzle header 122 and the large-flow-rate
10 nozzle header 142 are filled with cooling water in a short time, and the cooling water is
sprayed almost simultaneously from the small-flow-rate-side cooling water spray nozzles
126 of the small-flow-rate nozzle header 122, and the large-flow-rate-side cooling water
spray nozzles 146 of the large-flow-rate nozzle header 142.
[0078]
15 In addition, the water supply amount density ratio to be output from the above
host computer to the flow rate adjusting units 149 and 189 is calculated from the cooling
zone water supply amount density. However, although it is preferable that the water t
supply amount density ratio be a water supply amount density ratio proportional to the
number of nozzles of the large-flow-rate nozzle header 142 to the number of nozzles of
20 the small-flow-rate nozzle header 122 or a value close thereto, in either case, it is
necessary to set the pressures within both the headers 122 and 142 to a value equal to or
higher than the spray pattern securing limit pressure. Additionally, the cooling units
150 and 170 below the steel plate H are similarly adjusted.
[0079]
25 If the hot steel plate H is passed in the above state and its cooling is started,
^ 40
when the hot steel plate H passes through the steel plate cooling system 100, water filling
stop information is input from the host computer to the flow rate adjusting unit 149.
Thereby, by outputting the closing signals of the channel switching three-way valves 115
and 135 from the flow rate adjusting unit 149, the channel switching three-way valves
5 115 and 135 are closed to stop water supply. Accordingly, the spraying of the cooling
water from the small-flow-rate cooling water spray nozzle 122 and the large-flow-rate
cooling water spray nozzles 146 stops immediately.
[0080]
Although a case where cooling water is sprayed from both the small flow rate
10 cooling unit 110 and the large flow rate cooling unit 130 has been described above, in a
case where cooling water is sprayed only from the small flow rate unit 110, the zone
water supply amount density in the cooling zone where the steel plate cooling system 100
is arranged, and the information on a nozzle header (small-flow-rate water supply header
117) to supply water are input from the host computer to the flow rate adjusting units 149
15 and 189. Thereby, the opening degree of the flow rate regulating valve 114 of the unit
110 that is a water supply target is determined, and actuating signals are output from the
host computer to the flow rate adjusting units 149 and 189, similar to above, with respect
to the flow rate regulating valve 114 and the channel switching three-way valve 115.
[0081]
20 The present invention is not limited to the above first and the second
embodiments. That is,
(A) although the plate thickness has been described in the embodiments, the
present invention is may also be used for a thin plate and a shaped steel. Additionally, a
thick plate is also available for a roller quencher that is a cooling facility after heat
25 treatment.
41
(B) Although the flow rate adjusting units (control units) 149 and 189 are
provided in the upper cooling apparatus and the lower cooling apparatus, respectively,
one flow rate adjusting unit may control both the upper cooling apparatus and the lower
cooling apparatus.
5 (C) Although the full cone nozzles have been described in the above
embodiments, other types of nozzles can also be used in the present invention.
(D) In the above respective embodiment, the nozzle types and number of rows
of the upper cooling apparatus and the lower cooling apparatus may differ.
[0082]
10 Although the preferred first and second embodiments of the present invention
have been described above referring to the accompanying drawings, the present invention
is not limited to these embodiments. It is apparent to those skilled in the art that various
alterations or modifications are conceivable in the category of the idea set forth in the
claims, and it will be understood that these alterations or modifications naturally belongs
15 to the technical scope of the present invention.
Industrial Applicability
[0083]
The present invention is useful when a steel plate obtained by hot rolling is 20 cooled while allowing the steel plate to pass horizontally and restrictively between
constraining rolls.
Reference Signs List
[0084]
25 H: STEEL PLATE
42
1: COOLING SYSTEM
2: FINISH ROLLING MACHINE
3: HOT CORRECTING DEVICE
10a: CONSTRAINING ROLL
5 10b: CONVEYING ROLL
10: CONSTRAINING ROLL PAIR
11: UPPER COOLING APPARATUS
12: LOWER COOLING APPARATUS
20: FULL CONE SPRAY NOZZLE 10 21ato21i: SPRAY NOZZLE ROW
22: UPSTREAM SPRAY NOZZLE ROW GROUP
23: DOWNSTREAM SPRAY NOZZLE ROW GROUP
24: SUPPLY PIPE
30: NOZZLE BOX
15 31: UPSTREAM STORAGE CHAMBER
32: DOWNSTREAM STORAGE CHAMBER
40: HEADER
41: FLOW RATE REGULATING VALVE
42: PIPING
20 43: ON-OFF CONTROL VALVE
44: PIPING
45: ON-OFF CONTROL VALVE
50: WATER ON THE SURFACE
100: STEEL PLATE COOLING SYSTEM
25 110,150: SMALL-FLOW-RATE COOLING UNIT
% 43
112,152: SMALL-FLOW-RATE COOLING WATER SUPPLY PIPE
114,154: FLOW RATE REGULATING VALVE
115,155: CHANNEL-SWITCHING THREE-WAY VALVE j
117,157: SMALL-FLOW-RATE WATER SUPPLY HEADER
5 119,159: SMALL-FLOW-RATE NOZZLE WATER SUPPLY PIPE
122,162: SMALL-FLOW-RATE NOZZLE HEADER
126,166: SMALL-FLOW-RATE COOLING WATER SPRAY NOZZLE
130,170: LARGE-FLOW-RATE NOZZLE COOLING UNIT
132,172: LARGE-FLOW-RATE COOLING WATER SUPPLY PIPE
10 134,174: FLOW RATE REGULATING VALVE
135,175: CHANNEL SWITCHING THREE-WAY VALVE
137,177: LARGE-FLOW-RATE WATER SUPPLY HEADER
139, 179: LARGE-FLOW-RATE NOZZLE WATER SUPPLY PIPE
142,182: LARGE-FLOW-RATE NOZZLE HEADER
15 146,186: LARGE-FLOW-RATE COOLING WATER SPRAY NOZZLE
149, 189: FLOW RATE ADJUSTING UNIT

44
CLAIMS
1. A steel plate cooling system comprising:
a plurality of constraining roll pairs that allows a steel plate to pass restrictively
5 therebetween; and
an upper cooling apparatus and a lower cooling apparatus that are arranged
between the constraining roll pairs so as to be opposed to each other with the steel plate
interposed therebetween and have a plurality of spray nozzle rows,
wherein the plurality of spray nozzle rows is formed in a plate passing direction
10 of the steel plate, and each of the spray nozzle rows has a plurality of identical spray
nozzles lined up in a width direction of the steel plate,
wherein when viewed in the plate passing direction, the spray nozzle rows are
each classified into an upstream spray nozzle row group located on a relative upstream
side and a downstream spray nozzle row group located on a relative downstream side,
15 and
wherein a number of spray nozzles that belong to the upstream spray nozzle row
group is smaller than a number of spray nozzles that belong to the downstream spray
nozzle row group.
20 2. The steel plate cooling system according to Claim 1,
wherein a ratio of a total number of the respective spray nozzle rows and a
number of spray nozzle rows that belong to the upstream spray nozzle row group is equal
to or an integer ratio approaching the ratio of a maximum spraying amount and minimum
spraying amovmt of each spray nozzle that belongs to the spray nozzle rows.
25
45
3. The steel plate cooling system according to Claim 2, further comprising a
control unit that controls a cooling water to be sprayed toward the steel plate from the
plurality of spray nozzle rows,
wherein the control unit controls the spraying of the cooling water so that the
5 cooling water is caused to be sprayed from both the upsfream spray nozzle row group and
the downstream spray nozzle row group in a case where a total amount of water to be
sprayed toward the steel plate is equal to or larger than a maximum spraying amount of
the upstream spray nozzle row group, and the cooling water is caused to be sprayed only
from the upstream spray nozzle row group in a case where the total amount of water is
10 smaller than the maximum spraying amoimt of the upstream spray nozzle row group.
4. The steel plate cooling system according to Claim 3, flirther comprising:
a water supply header that supplies the cooling water to the upstream spray
nozzle row group and the downsfream spray nozzle row group;
15 a flow rate regulating valve that regulates the flow rate of the cooling water to be
supplied to the water supply header;
a first control valve that controls a permission or prohibition of supply of the
cooling water to be supplied from the water supply header to the upstream spray nozzle
row group; and
20 a second control valve that controls a permission or prohibition of supply of the
cooling water to be supplied from the water supply header to the downsfream spray
nozzle row group.
5. The steel plate cooling system according to Claim 1, further comprising:
25 a first water supply header that supplies a cooling water to the upsfream spray
46
nozzle row group;
a second water supply header that supplies a cooling water to the downstream
spray nozzle row group;
a first flow rate regulating valve that regulates a flow rate of the cooling water to
5 be supplied to the first water supply header;
a second flow rate regulating valve that regulates a flow rate of the cooling
water to be supplied to the second water supply header; and
a control unit that controls the cooling water to be sprayed toward the steel plate
fi-om the plurality of spray nozzle rows,
10 wherein the control unit controls the spraying of the cooling water so that the
cooling water is caused to be sprayed fi-om both the upstream spray nozzle row group and
the downstream spray nozzle row group in a case where a total amount of water to be
sprayed toward the steel plate is equal to or larger than a maximum spraying amount of
the upstream spray nozzle row group, and the cooling water is caused to be sprayed only
15 fi-om the upstream spray nozzle row group in a case where the total amount of water is
smaller than the maximum spraying amount of the upstream spray nozzle row group.
6. The steel plate cooling system according to any one of Claims 1 to 5,
wherein a mutually adjacent intervals, in the plate passing direction, of the
20 respective spray nozzle rows that belong to the upstream spray nozzle row group are the
same, and
wherein a mutually adjacent intervals, in the plate passing direction, of the
respective spray nozzle rows that belong to the downstream spray nozzle row group are
the same.
25
^ 47
7. The steel plate cooling system according to any one of Claims 1 to 5,
wherein all the adjacent intervals of the respective spray nozzle rows in the plate
passing direction are the same.
5 8. The steel plate cooling system according to any one of Claims 1 to 5,
wherein the upstream spray nozzle row group is arranged so that a cooling water
is sprayed from the upstream spray nozzle row group toward a position of the upstream
side in the plate passing direction not overlapped with a region of a water flow on a
surface that accumulates on the steel plate when a maximum spraying amount is caused
10 to be sprayed from the upsfream spray nozzle row group.
9. A steel plate cooling method, when a steel plate is cooled using the steel
plate cooling system according to any one of Claims 3 to 5,
the spraying of the cooling water is controlled by the confrol unit so that the
15 cooling water is caused to be sprayed from both the upstream spray nozzle row group and
the downstream spray nozzle row group in a case where the total amount of water to be
sprayed toward the steel plate is equal to or larger than the maximum spraying amount of
the upstream spray nozzle row group, and the cooling water is caused to be sprayed only
from the upstream spray nozzle row group in a case where the total amoimt of water is
20 smaller than the maximum spraying amount of the upstream spray nozzle row group.
10. The steel plate cooling method according to Claim 9,
wherein a region of a water flow on a surface that accumulates on the steel plate
when the cooling water is caused to be sprayed with the maximum spraying amount from
25 the upsfream spray nozzle row group is obtained in advance, and
41
48
wherein the upstream spray nozzle row group is arranged so that the cooling
water is sprayed from the upstream spray nozzle row group toward a position of the
upstream side in the plate passing direction not overlapped with the region.