1. A hot rolling control device, comprising: an open mode start timing determining section (1 03) that determines timing of starting cooling of a plurality of table rolls (1 70) comprising a run-out table that conveys a strip (151) rolled by a hot rolling machine (152) while cooling the strip (151) by a strip cooling apparatus (160, 163) provided on a delivery side of the hot rolling machine (1 52), from position information on a top end of the strip (151), for a table roll cooling apparatus (171) as a control target provided with a plurality of cooling water opening closing apparatuses (172) arranged along a flow direction of the strip (151) for the plurality of table rolls (170); an open mode priority storage section (105) that opens the plurality of cooling water opening closing apparatuses (172) when starting cooling of the plurality of table rolls (170) and stores a first priority for discharging cooling water; and a table roll cooling water control section (110) that performs control of opening the plurality of cooling water opening closing apparatuses (172) at timing of starting the cooling determined by the open mode start timing determining section (1 03) according to the first priority collected from the open mode priority storage section (105) and at time intervals under a certain condition.

2. The hot rolling control device according to claim 1, further comprising: a closed mode start timing determining section (1 04) that determines timing of starting cooling end processing of the plurality of table rolls (170) from position information on a tail end of the strip (151) collected from the control target; and a closed mode priority storage section (106) that closes the plurality of cooling water opening closing apparatuses (172) during cooling end processing on the plurality of table rolls (170) and stores a second priority for stopping discharge of the cooling water, wherein the table roll cooling water control section (110) performs control of closing the plurality of cooling water opening closing apparatuses (172) at timing of starting the cooling end processing determined by the closed mode start timing determining section (1 04), according to the second priority collected from the closed mode priority storage section (1 06) and at time intervals under a certain condition.

3. The hot rolling control device according to claim 2, wherein a time after a cooling water opening closing apparatus (172) is opened based on the first priority until another cooling water opening closing apparatus (172) with the next priority is opened and a time after a cooling water opening closing apparatus (172) is closed based on the second priority until another cooling water opening closing apparatus (172) with the next priority is closed are predetermined as the time interval under a certain condition.

4. The hot rolling control device according to claim 2, wherein the time interval under a certain condition is a time until a deviation between a coiling temperature of the strip (151) and a target value becomes smaller than a tolerance.

5. The hot rolling control device according to claim 2, wherein the open mode priority storage section (105) stores order in which the plurality of cooling water opening/closing apparatuses (172) stratified according to one or more pieces of strip information including at least a steel grade or strip thickness of the strip (151) are opened and the closed mode priority storage section (106) stores order in which the plurality of cooling water openinglclosing apparatuses (172) stratified according to one or more pieces of strip information including at least the steel grade or strip thickness of the strip (151) are closed.

6. The hot rolling control device according to claim 3, wherein a time after a cooling water openinglclosing apparatus (172) is opened based on the first priority until another cooling water openinglclosing apparatus (172) with the next priority is opened and a time after a cooling water openinglclosing apparatus (172) is closed based on the second priority until another cooling water openinglclosing apparatus (172) with the next priority is closed are stratified according to one or more pieces of strip information including at least the steel grade or strip thickness of the strip (151).

7. A hot rolling control method comprising: determining, by an open mode start timing determining section (1 03), timing of starting cooling of a plurality of table rolls (170) cooled by a table roll cooling apparatus (171) provided with a plurality of cooling water opening/closing apparatuses (1 72) arranged along a flow direction of a strip (1 5 I), from position information on a top end of the rolled strip (151) in a cooling process, the strip (1 5 1) being rolled and conveyed on a run-out table comprising the plurality of table rolls (1 70); and opening, by a table roll cooling water control section (11O), the plurality of cooling water openinglclosing apparatuses (172) at the timing of starting cooling determined by the open mode start timing determining section (1 03) according to priority for discharging cooling water by opening the plurality of cooling water opening/closing apparatuses (172) when starting cooling of the plurality of table rolls (170) stored in the open mode priority storage section (105) and at a time interval under a certain condition.

BACKGROUND OF THE INVENTION
(1) FIELD OF THE INVENTION
The present invention relates to a hot rolling control device and a hot rolling
control method suitably applicable to cooling control of a table roll of a run-out table (hereinafter
5 may be described as "ROT") in hot rolling mill equipment.
(2) DESCRIPTION OF THE RELATED ART
Examples of a cooling scheme of an ROT table roll include internal water cooling
that causes cooling water to circulate inside a table roll and external water cooling that sprays
10 water over a table roll from outside. Since the internal water cooling system is expensive, it is
often the case that internal water cooling is normally applied to only a table roll located in the
vicinity of a position at which a measuring instrument such as thermometer is installed and
external water cooling is applied to other table rolls. However, there is concern that a tracking
sensor that detects a top end of a strip may malfunction due to environmental deterioration
15 caused by spraying of water of external water cooling. For this reason, a method is generally
used which sprays external cooling water after a top end of the strip is wound around a down
cooler and stops the external cooling water before a tail end of the strip exits from a finishing
mill. However, there is a problem that a switchover between spraying and stop of the cooling
water over the table roll under rolling results in a deviation of temperature of the strip
20 immediately before being wound up by the down coiler (coiling temperature).
An example of a conventional method of cooling a table roll of ROT by taking
into account a deviation in a coiling temperature is a technique described in JP-A-9-108 12. JPA-
9-1 08 12 discloses a technique that when a table roll is divided into a plurality of zones,
spraying of cooling water is started in order from a zone through which a top end of a strip
25 passes among respective zones of the table roll, and an amount of water injection of strip cooling
equipment is reduced in accordance with spraying of the table roll cooling water to thereby
prevent a drop of the coiling temperature.
SUMMARY OF THE INVENTION
3 0 However, the technique described in JP-A-9-108 12 involves the following
problem. When spraying of the table roll cooling water is simply started in order from the zone
through which the top end of the strip passes, there is a division between a region where the top
end (portion of a certain length from the top end) of the strip is sprayed with the table roll
cooling water and a region where the top end of the strip is not sprayed with the table roll
cooling water. As a result, the coiling temperature greatly varies between both regions. In
5 order to favorably apply the method in JP-A-9- 108 12 that compensates for this temperature
change by reducing the amount of water injection of the strip cooling equipment, it is necessary
to first grasp a relationship between the amount of water injection and a temperature drop, adjust
the amount of reduction of water injected to an appropriate value and synchronize the timing of
reducing the amount of water injection with an influence of the table roll cooling water on the
10 coiling temperature. Since the effect of the table roll cooling water on the strip temperature and
the effect of the water injection from the cooling equipment that cools the strip have a
relationship interacting with each other, attention should also be paid to the fact that a change in
the strip temperature varies when spraying of the table roll cooling water and water injection are
performed and when spraying of the table roll cooling water and water injection are performed
15 separately.
However, since these cannot be easily realized in general, the technique described
in JP-A-9-108 12 has a problem that the coiling temperature of the strip varies.
In view of the above-described situation, there is a demand for suppressing the
influence of the table roll cooling water on the strip temperature during cooling of the rolled
20 strip.
In one aspect of the present invention, an open mode start timing determining
section determines timing of starting cooling of a plurality of table rolls from position
information on a top end of a rolled strip under cooling when a run-out table is conveyed which
is made up of the plurality of table rolls, cooled by a table roll cooling apparatus provided with a
25 plurality of cooling water opening/closing apparatuses arranged in a flow direction of the strip.
Next, a table roll cooling water control section sequentially opens the plurality of
cooling water opening/closing apparatuses at the timing of starting cooling determined by the
open mode start timing determining section according to priority for discharging cooling water
by opening the plurality of cooling water opening/closing apparatuses when starting cooling of
30 the plurality of table rolls stored in an open mode priority storage section and at time intervals
under a certain condition.
According to at least one aspect of the present invention, priority in which a
plurality of cooling water opening/closing apparatuses are opened is stored when cooling of the
plurality of table rolls is started, and the plurality of cooling water opening/closing apparatuses
are opened at time intervals under a certain condition according to the priority. Thus, it is
possible to suppress the influence of the table roll cooling water on a strip temperature during
cooling of the rolled strip by sequentially opening the plurality of cooling water opening/closing
apparatuses based on the priority and at the time intervals with particular attention paid to the
5 influence on the strip temperature.
Other objects, features and advantages of the invention will become apparent
from the following description of the embodiments of the invention taken in conjunction with the
accompanying drawings.
10 BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a diagram illustrating a configuration example of a hot rolling system
according to a first embodiment of the present invention;
Fig. 2 is a diagram illustrating a configuration example of an open mode priority
storage section in Fig. 1 ;
15 Fig. 3 is a diagram illustrating a configuration example of a closed mode priority
storage section in Fig. 1 ;
Fig. 4 is a diagram illustrating a configuration example of an open mode interval
storage section in Fig. 1 ;
Fig. 5 is a diagram illustrating a configuration example of a closed mode interval
20 storage section in Fig. 1 ;
Fig. 6 is a flowchart illustrating processing of an open mode stast timing
determining section in Fig. 1 ;
Fig. 7 is a flowchart illustrating processing of a closed mode start timing
determining section in Fig. 1 ;
25 Fig. 8 is a flowchart illustrating processing of a table roll cooling water control
section in Fig. 1 ;
Fig. 9 is a diagram illustrating a configuration example of a hot rolling system
according to a second embodiment of the present invention;
Fig. 10 is a flowchart illustrating processing of the table roll cooling water control
30 section in Fig. 9;
Fig. 11 is a diagram illustrating a configuration example of an open mode priority
storage section in Fig. 9;
Fig. 12 is a diagram illustrating a configuration example of a closed mode priority
storage section in Fig. 9; and
Fig. 13 is a block diagram illustrating an example of a hardware configuration of
a computer.
DETAILED DESCRIPTION OF THE INVENTION
5 Hereinafter, embodiments for implementing the present invention will be
described in detail with reference to the accompanying drawings. Description will be given in
the following order. Common components among respective drawings are assigned the same
reference numerals and overlapping description will be omitted.
1. First embodiment (example where an interval storage section is provided)
10 2. Second embodiment (example where a coiling temperature deviation calculation section is
provided)
3. Third embodiment (example where the same priority is assigned to cooling water
opening/closing apparatus numbers)
4. Others
15 4 . First embodiment>
Fig. 1 is a diagram illustrating a configuration example of a hot rolling system 1
according to a first embodiment of the present invention.
The hot rolling system 1 is constructed of a hot rolling control device 100 and a
control target 150. The hot rolling control device 100 receives various signals from the control
20 target 150, generates control signals based on the received signals and outputs the control signals
to the control target 150.
A configuration example of the control target 150 will be described first.
In the present embodiment, the control target 150 is a coiling temperature control
line of the hot rolling system 1, so-called "run-out table (ROT)." In the coiling temperature
25 control line, a strip 15 1 having a temperature of, for example, 850°C to 950°C rolled by a mill
153 of a hot rolling machine 152 is cooled by a laminar cooling apparatus 160 that performs
water cooling from above the strip 15 1 and a spray cooling apparatus 163 that performs water
cooling from below, and wound up by a down cooler 157. The laminar cooling apparatus 160
and the spray cooling apparatus 163 are examples of a strip cooling apparatus.
30 The laminar cooling apparatus 160 and the spray cooling apparatus 163 are each
provided with a plurality of banks 16 1, each of which combines a predetermined number of
cooling headers 162 that discharge water. The actual banks 16 1 of the laminar cooling
apparatus 160 and spray cooling apparatus 163 are arranged between table rolls 170.
The strip 15 1 is conveyed while being supported by many table rolls 170 on the
ROT. When the table rolls 170 are repeatedly heated to a high temperature through contact
with the strip 15 1, cracking may occur in the table rolls 170. Thus, the table rolls 170 are
cooled by a table roll cooling apparatus 171 for longevity thereof. The many table rolls 170 are
divided into a plurality of zones in the flow direction of the strip 15 1 and a cooling water
5 opening/closing apparatus 172 is disposed for each zone.
The table roll cooling apparatus 171 switches between spraying and stop of
cooling water in each zone by opening/closing a valve of each cooling water opening/closing
apparatus 172. Fig. 1 shows an example where the many table rolls 170 are grouped into ten
zones and the table roll cooling apparatus 171 is constructed of ten cooling water
10 opening/closing apparatuses 172. The ten cooling water opening/closing apparatuses 172 are
numbered (#1 to #lo) from the hot rolling machine 152 side to the down cooler 157.
Hereinafter, opening/closing the valves of the cooling water opening/closing apparatuses 172
will be described as "opening/closing the cooling water opening/closing apparatuses 172."
A load cell 153w is provided at the top of the mill 153 of the hot rolling machine
15 152 as a measuring instrument to measure a rolling force on the strip 15 1. The load cell 153w
measures the rolling force on the strip 15 1 and detects whether rolling is in progress or not (that
is, presence or absence of the strip 15 1) based on whether the measured value has exceeded a
predetermined threshold or not. The load cell 153w outputs the detection result to a data
gathering section 102 of the hot rolling control device 100.
20 A finishing mill delivery temperature pyrometerl54 measures a temperature of
the strip 15 1 immediately after it is rolled by the hot rolling machine 152 and outputs the
measurement result to the data gathering section 102 of the hot rolling control device 100.
A coiling temperature pyrometer 155 measures a temperature of the strip 15 1
immediately before it is wound up by the down cooler 157 and outputs the measurement result to
25 the data gathering section 102 of the hot rolling control device 100. A plurality of HMDs (Hot
Metal Detectors) 156 (only one of which are shown in Fig. 1) arranged on the ROT are sensors
that detect a passage of a top end and a tail end of the strip 15 1. Such sensors are also called
"tracking sensors." The output of the HMD 156 is turned ON upon detecting a passage of the
top end and the tail end of the strip 15 1 and turned OFF upon detecting no passage.
3 0 An object of coiling temperature control is to cause the coiling temperature of the
strip 15 1 to match a target temperature. The target temperature may be constant in the strip
length direction of the strip 15 1, but different values may be set depending on each region such
as setting a slightly higher temperature for the top end and the tail end.
Next, a configuration example of the hot rolling control device 100 will be shown.
The hot rolling control device 100 is provided with various calculation and
control functions including calculations of a roll down position of the mill 153 and a roll speed,
but only functions relating to the table roll cooling apparatus 171 will be described in the present
embodiment.
5 The hot rolling control device 100 is connected to a host computer 50. The hot
rolling control device 100 is provided with a command receiving section 10 1, the data gathering
section 102, an open mode start timing determining section 103, and a closed mode start timing
determining section 104. Furthermore, the hot rolling control device 100 is also provided with
an open mode priority storage section 105, a closed mode priority storage section 106, an open
10 mode interval storage section 107, a closed mode interval storage section 108, and a table roll
cooling water control section 1 10.
The command receiving section 101 receives specification information such as a
steel grade, strip thickness, strip width of the strip 15 1 to be cooled and a target temperature of
coiling temperature or the like.
15 The data gathering section 102 collects, from the control target 150, various
signals such as a speed of the strip 15 1, a detection result by the load cell 153w as to the
presence or absence of the strip 15 1, ON/OFF information of the I-IMD 156, a finishing mill
delivery temperature measured by the finishing mill delivery temperature pyrometer 154 and a
coiling temperature measured by the coiling temperature pyrometer 155.
20 The open mode start timing determining section 103 determines timing at which
the cooling water opening/closing apparatus 172 of the table roll cooling apparatus 17 1 starts
(starts an open mode) cooling of the table roll 170 based on position information on the top end
of the strip 151 collected from the control target 150.
The closed mode start timing determining section 104 determines timing at which
25 the cooling water opening/closing apparatus 172 starts (starts a closed mode) cooling end
processing based on position information on the tail end of the strip 15 1 collected from each
control target 150.
The open mode priority storage section 105 stores order (priority) in which each
cooling water opening/closing apparatus 172 is opened to discharge cooling water.
30 The closed mode priority storage section 106 stores order (priority) in which each
cooling water opening/closing apparatus 172 is closed to stop discharge of cooling water.
The open mode interval storage section 107 stores a time interval between
priorities when each cooling water opening/closing apparatus 172 is opened.
The closed mode interval storage section 108 stores a time interval between
priorities when each cooling water opening/closing apparatus 172 is closed.
Upon receiving a command of cooling control of the table roll 170 from the
command receiving section 101, the table roll cooling water control section 11 0 starts cooling of
the table roll 170 by the cooling water opening/closing apparatuses 172 according to timing
5 determined by the open mode start timing determining section 103. In this case, the table roll
cooling water control section 11 0 reads set values stored in the open mode priority storage
section 105 and the open mode interval storage section 107 and opens the cooling water
opening/closing apparatuses 172.
The table roll cooling water control section 11 0 starts cooling end processing on
10 the table rolls 170 by the cooling water opening/closing apparatuses 172 according to timing
determined by the closed mode start timing determining section 104. In this case, the table roll
cooling water control section 11 0 reads the set values stored in the closed mode priority storage
section 106 and the closed mode interval storage section 108 and closes the cooling water
opening/closing apparatuses 172.
15 A tolerance of a coiling temperature varies depending on a cooling specification
of the strip 15 1 and influences of the table roll cooling water on a strip temperature also varies
depending on the cooling specification, strip thickness and speed of the strip 15 1. The strip
speed is generally calculated from a strip thickness and other conditions through model
calculations. For this reason, regarding the priority and interval, it is preferable to store
20 appropriate values in each storage section according to the specification of the strip 15 1. In the
present embodiment, each storage section stores order in which each cooling water
opening/closing apparatus 172 is opened or closed or a time interval at which each cooling water
opening/closing apparatus 172 is opened or closed stratified with one or more pieces of strip
information including at least the steel grade or strip thickness of the strip 15 1.
2 5 Fig. 2 is a diagram illustrating a configuration example of the open mode priority
storage section 105.
Regarding the steel grade, strip thickness and the cooling water opening/closing
apparatuses 172 of #1 to #lo, this storage section stores priority of each cooling water
opening/closing apparatus 172 when each cooling water opening/closing apparatus 172 is
30 released (opened). Here, priority becomes higher as the number assigned thereto increases. In
Fig. 2, examples of steel grade include SS steel and DP (Dual Phase) steel. DP steel is two phase
type steel in which a soft metallographic structure and a hard metallographic structure
coexist, and is high tensile steel having high tensile strength. Here, SS400 is shown as an
example of SS steel and DP-1 is shown as DP steel, but it goes without saying that the present
invention is also applicable to other metal plates.
For example, when the steel grade is SS400 and strip thickness is 1.2 to 2.0 mm,
priority of the cooling water opening/closing apparatus 172 of # 10 closest to the down cooler 157
is set to be highest, indicating that it is closed first. Furthermore, the priority of the cooling
5 water opening/closing apparatus 172 of #4 is set to 7, the priority of the cooling water
opening/closing apparatus 172 of #3 is set to 8, the priority of the cooling water opening/closing
apparatus 172 of #2 is set to 9, and the priority of the cooling water opening/closing apparatus
172 of #4 is set to 10, showing that the closer to the hot rolling machine 152 the cooling water
opening/closing apparatus 172 is, the lower priority is set and the later it is closed. Thus, with
10 the thin strip 15 1, since the influence of the table roll cooling water on the strip coiling
temperature is large, higher priority is assigned to the cooling water opening/closing apparatuses
172 in order of closeness to the down cooler 157. Thus, the closer to the top end of the strip
15 1, the shorter is the time during which table roll cooling water is sprayed, and it is thereby
possible to alleviate (minimize) the influence thereof. In this case, the range of influences of
15 the table roll cooling water on the strip length direction of the strip 15 1 tends to widen.
On the other hand, with SS400 having a strip thickness of 12.0 to 17 mm, the
influence of the table roll cooling water is smaller compared to the case with a thin plate. Thus,
the cooling water opening/closing apparatus 172 is opened from the mill 153 side to narrow the
range of influences of the table roll cooling water on the strip length direction of the strip 15 1.
20 In the case of DP steel, of the laminar cooling apparatus 160 and the spray cooling
apparatus 163, only the cooling headers 162 closer to the mill 153 and the cooling headers 162,
closer to the down cooler 157 are opened and intermediate cooling headers 162 for securing an
air cooling retention time at an intermediate temperature are closed.
In the case of DP steel, such as DP-I, the cooling water opening/closing
25 apparatuses 172 at intermediate positions of #3 and #4 are opened first, then the cooling water
opening/closing apparatus 172 of #10 close to the down cooler 157 is then opened, and after that
the cooling water opening/closing apparatuses 172 of #l and #2 close to the mill 153 are opened.
Control is performed on special cooling steel having a high degree of difficulty in control such as
DP steel, such that the cooling water openingclosing apparatuses 172 adaptable to an air cooling
30 region (intermediate part) having a large influence on the steel temperature are opened first and
to thereby terminate disturbance factors against temperature control in early stages.
Fig. 3 is a diagram illustrating a configuration example of the closed mode
priority storage section 106.
Priority of each cooling water opening/closing apparatus 172 is stored [or the
steel grade, strip thickness and the cooling water openin/closing apparatuses 172 of # 1 to # 10
when the cooling water opening/closing apparatuses 172 are closed.
For example, when the steel grade is SS400 and the strip thickness is 12.0 to 17.0
nim, highest priority is set for the cooling water opening/closing apparatus 172 of #l closest to
5 the hot rolling machine 152, showing that it is closed first. Furthermore, the priority of the
cooling water opening/closing apparatus 172 of #4 is set to 4, the priority of the cooling water
opening/closing apparatus 172 of #3 is set to 3, the priority of the cooling water opening/closing
apparatus 172 of #2 is set to 2, and the priority of the cooling water opening/closing apparatus
172 of #1 is set to 1, showing that the closer to the hot rolling machine 152 the cooling water
10 opening/closing apparatus 172 is, the higher priority is set and the earlier it is closed.
Fig. 4 is a diagram illustrating a configuration example of the open mode interval
storage section 107.
When the table roll cooling apparatus 171 starts water cooling, a time interval
after a certain cooling water opening/closing apparatus 172 is opened for the steel grade and strip
15 thickness, the next cooling water opening/closing apparatus 172 is opened is stored as an
interval.
The smaller the interval, the more quickly the cooling of the table roll 170 in the
next zone can be started, but the influence on the strip coiling temperature as disturbance
increases.
Conversely, the greater the interval, the ignore the influence on the strip coiling
temperature is alleviated, but since the time during which some of the table rolls 170 are not
cooled is extended, and there is concern that the service life of the table rolls 170 may be
affected.
The example in Fig. 4 shows that the interval is 3.0 seconds when the steel grade
25 is SS400 and the strip thickness is 1.2 to 2.0 mm, and the table roll cooling apparatus 171 having
the highest priority starts water cooling, and the cooling water opening/closing apparatuses 172
are then sequentially opened in order of priority at intervals of 3.0 seconds.
The example in Fig. 4 also shows that the interval when the steel grade is SS400
and the strip thickness is 12.0 to 17.0 mm is 1.5 seconds, and the table roll cooling apparatus 171
30 starts water cooling, and the cooling water opening/closing apparatuses 172 are then sequentially
opened in order of priority at intervals of 1.5 seconds.
In the case of a thin strip 15 1, since the table roll cooling water has considerable
influences on the strip temperature, a larger interval is set to alleviate the influence in the present
embodiment.

On the other hand, in the case of DP steel, the strip coiling temperature is low and
the strip is passed through at a low speed, and therefore the influence of the table roll cooling
water on the strip 15 1 is greater. For this reason, a greater interval is set for the DP steel to
alleviate the influence of the table roll cooling water on the strip temperature.
5 Fig. 5 is a diagram illustrating a configuration example of the closed mode
interval storage section 108.
When the table roll cooling apparatus 171 finishes water cooling, a time interval
after a certain cooling water opening/closing apparatus 172 is closed for the steel grade and strip
thickness, the next cooling water opening/closing apparatus 172 is closed is stored as an interval.
10 The example in Fig. 5 shows that the interval is 2.0 seconds when the steel grade
is DP-1 and the strip thickness is 1.2 to 2.0 mm, and when the table roll cooling apparatus 171
finishes water cooling, the cooling water opening/closing apparatuses 172 are sequentially closed
in order of priority at intervals of 2.0 seconds.
The example in Fig. 5 also shows that the interval is 1.0 second when the steel
15 grade is DP-1 and the strip thickness is 12.0 to 17.0 mm, and the cooling water opening/closing
apparatuses 172 are sequentially closed in order of priority at intervals of 1.0 seconds.
The present embodiment assumes that the interval has a single value for each steel
grade and strip thickness, but the interval may be made to vary depending on priority. That is,
for example, the interval after the cooling water opening/closing apparatus 172 of priority 1 is
20 operated until the cooling water opening/closing apparatus 172 of priority 2 is operated may be
set to a value different from the interval after the cooling water opening/closing apparatus 172 of
priority 2 is operated until the cooling water opening/closing apparatus 172 of priority 3 is
operated. In this case, the present invention is also applicable as is by storing the values of the
respective intervals in the open mode interval storage section 107 and the closed mode interval
25 storage section 108.
[Processing of open mode start timing determining section]
Fig. 6 is a flowchart illustrating processing of the open mode start timing
determining section 103.
The open mode start timing determining section 103 determines the timing at
30 which the table roll cooling apparatus 171 starts cooling (open mode start timing) and notifies
the timing to the table roll cooling water control section 110.
The open mode start timing determining section 103 first determines whether the
top end of the strip 15 1 has passed through the I-IMD 156 immediately before the down cooler
157 (step S 1). When the top end of the strip 15 1 has passed through the HMD 156, the open
mode start timing determining section 103 notifies the table roll cooling water control section
1 10 of the start (open mode operation start) of water spraying by the table roll cooling apparatus
171 (step S2).
In the present embodiment, the timing at which the top end of the strip 15 1 passes
5 through the HMD 156 immediately before the down cooler 157 is assumed to be timing of
starting water spraying of the table roll cooling water control section 11 0 so as to prevent the
table roll cooling water from causing malfunction of the HMD 156 on the ROT, but the present
invention is not limited to this example. For example, the timing at which the top end of the
strip 15 1 is wound around the down cooler 157 may be assumed to be timing of starting water
10 spraying. The timing at which the top end of the strip 151 is wound around the down cooler 157
can be calculated from a detection result of the HMD 156 and a rolling speed of the mill 153.
Alternatively, timing at which tension of the strip 15 1 is established between the down cooler 157
and the mill 153 and the strip 15 1 becomes stable may also be assumed to be timing of starting
water spraying. The tension of the strip 15 1 can be determined by a rise in the value of a
15 current flowing through the strip 15 1.
[Processing of closed mode start timing determining section]
Fig. 7 is a flowchart illustrating processing of the closed mode start timing
determining section 104.
The closed mode start timing determining section 104 determines timing at which
20 the table roll cooling apparatus 171 starts cooling end processing (closed mode start timing) and
notifies the timing to the table roll cooling water control section 11 0.
First, the closed mode start timing determining section 104 determines whether
the tail end of the strip 15 1 has exited from the mill 153 or not based on the detection result of
the load cell 153w (step S 1 1). When the tail end of the strip 15 1 has exited from the mill 153
25 (detection result: OFF), the closed mode start timing determining section 104 instructs the table
roll cooling water control section 110 about an end of water spraying by the table roll cooling
apparatus 171 (closed mode operation start) (step S 12).
In the present embodiment, the timing at which the tail end of the strip 15 1 has
exited from the mill 153 is assumed to be timing of starting water spraying end processing by the
30 table roll cooling water control section 110 so that the table roll cooling water does not become
noise in the tail end detection of the strip 15 1, but the present invention is not limited to this
example. For example, in consideration of a delay in operation of the cooling water
opening/closing apparatus 172, timing ahead of the timing at which the tail end of the strip 15 1
exits from the mill 153 may be assumed to be timing of starting the water spraying end
processing by the table roll cooling water control section 11 0.
[Processing of table roll cooling water control section]
Fig. 8 is a flowchart illustrating processing of the table roll cooling water control
section 1 10.
5 Fig. 8 illustrates processing from start to end of cooling of the strip 15 1.
The actual hot rolling system 1 starts the processing shown in Fig. 8 prior to entry
of the strip 15 1 into the ROT, and after all the cooling water opening/closing apparatuses 172
complete the cooling, the system ends this processing. These steps are repeated on the strip 15 1
to be rolled. For simplicity, the present embodiment will describe a case as an example where
10 the cooling water opening/closing apparatuses 172 are opened one by one when cooling is
started, and conversely when cooling is completed, the cooling water opening/closing
apparatuses 172 are closed one by one. Note that the present embodiment shows an example
where all the cooling water opening/closing apparatuses 172 are opened, but there may also be
operation whereby specific cooling water opening/closing apparatuses 172 are kept closed.
15 First, the table roll cooling water control section 11 0 determines whether an open
mode start timing signal is received from the open mode start timing determining section 103 or
not (step S21).
Upon receiving the open mode start timing signal, the table roll cooling water
control section 11 0 outputs, to the table roll cooling apparatus 171, a signal to open one of the
20 cooling water opening/closing apparatuses 172 according to the priority of each cooling water
opening/closing apparatus 172 corresponding to the steel grade and strip thickness of the strip
15 1 collected from the open mode priority storage section 105 (step S22).
Next, the table roll cooling water control section 1 10 determines whether all the
cooling water opening/closing apparatuses 172 have been opened or not (step S23). When all
25 the cooling water opening/closing apparatuses 172 have been opened, the opening processing
ends, and so the process moves to step S25.
When all the cooling water opening/closing apparatuses 172 have not been
opened, the table roll cooling water control section 110 collects an interval corresponding to the
steel grade and strip thickness of the strip 15 1 from the open mode interval storage section 107,
30 and determines whether the time corresponding to the interval has been elapsed or not after
previously opening the cooling water opening/closing apparatus 172 (step S24).
When the time corresponding to the interval has not elapsed, the table roll cooling
water control section 110 repeats the determination processing in step S24. When the time
corresponding to the interval has elapsed, the table roll cooling water control section 110 returns
- 14 -
to step S22 and performs processing of opening the cooling water opening/closing paratus 172
with the next priority. Hereinafter, processes in steps S22 to S24 are repeated.
When all the cooling water opening/closing apparatuses 172 have been opened,
the table roll cooling water control section 11 0 determines whether a closed mode start timing
5 signal is received from the closed mode start timing determining section 104 or not (step S25).
Upon receiving the closed mode start timing signal, the table roll cooling water
control section 110 outputs, to the table roll cooling apparatus 171, a signal to close one of the
cooling water opening/closing apparatuses 172 according to the priority of each cooling water
opening/closing apparatus 172 corresponding to the steel grade and strip thickness of the strip
10 151 collected from the closed mode priority storage section 106 (step S26).
Next, the table roll cooling water control section 11 0 determines whether all the
cooling water opening/closing apparatuses 172 have been closed or not (step S27). When all
the cooling water opening/closing apparatuses 172 have been closed, the processing of closing
the cooling water opening/closing apparatuses 172 is completed, and therefore the processing on
15 the strip 15 1 by the table roll cooling water control section 1 10 ends.
When all the cooling water opening/closing apparatuses 172 have not been
closed, the table roll cooling water control section 11 0 collects an interval corresponding to the
steel grade and strip thickness of the strip 15 1 from the closed mode interval storage section 108,
and determines whether the time corresponding to the interval has elapsed or not after previously
20 closing the cooling water opening/closing apparatus 172 (step S28).
When the time corresponding to the interval has not elapsed, the table roll cooling
water control section 11 0 repeats the determination processing in step 28. When the time
corresponding to the interval has elapsed, the table roll cooling water control section 110 moves
to step S26 and performs processing of closing the cooling water opening/closing apparatus 172
with the next priority. wherein a fier, the processes in step S26 to step S28 are repeated.
As described above, the table roll cooling water control section 110 starts water
spraying according to the open mode start timing signal from the open mode start timing
determining section 103 and opens the cooling water opening/closing apparatuses 172 according
to the priority collected from the open mode priority storage section 105. In this case, the
30 cooling water opening/closing apparatuses 172 are opened at the time interval collected from the
open mode interval storage section 107. Furthermore, the table roll cooling water control
section 11 0 ends the operation of ending water spraying according to the closed mode start
timing signal from the closed mode start timing determining section 104 and closes the cooling
water opening/closing apparatuses 172 according to the priority collected from the closed mode
priority storage section 106. In this case, the table roll cooling water control section 11 0 closes
the cooling water opening/closing apparatuses 172 at the time interval collected from the closed
mode interval storage section 108.
In the present embodiment, the plurality of cooling water opening/closing
5 apparatuses 172 of the table roll cooling apparatus 171 are sequentially opened/closed based on
the priority and time interval in consideration of the influence of the strip 15 1 on the coiling
temperature. In this case, the cooling water opening/closing apparatuses 172 are opened or
closed in order in which the influence on the coiling temperature becomes minimal for each zone
of the ROT. Furthermore, the interval of opening/closing operations is changed in accordance
10 with the thickness and speed of the strip to minimize variations in influences of the strip 15 1 on
the coiling temperature.
According to the present embodiment configured as described above, spraying or
stop of spraying of the table roll cooling water by opening/closing of the cooling water
opening/closing apparatus 172 will not affect detection of the top end and tail end of the strip
15 15 1. That is, malfunction of the HMD 156 can be prevented. In addition, the influence of the
strip 15 1 on the coiling temperature can be maintained within a certain range.
According to the present embodiment, the cooling water opening/closing
apparatuses 172 are gradually and sequentially opened/closed based on simple table reading in
the coiling cooling step in the hot rolling system 1, and it is thereby possible to control
20 influences of the table roll cooling water on the strip temperature within a predetermined range
(e.g., +lo% of target temperature) and consequently increase the accuracy of the coiling
temperature in the strip length direction of the strip 15 1.
Thus, a coiling temperature can be obtained with high accuracy in any region of
the strip 15 1 in the strip length direction in coiling temperature control of the strip 15 1 after hot
25 rolling. As a result, it is possible to improve composition quality of the strip 15 1 and obtain a
good strip shape at the same time.
In Fig. 8, the processing of opening/closing the cooling water opening/closing
apparatuses 172 is performed according to predetermined priority but priority may be applied
when each cooling water opening/closing apparatus 172 is either opened or closed.
30 <2. Second embodiment>
Fig. 9 is a diagram illustrating a configuration example of a hot rolling system 1A
according to a second embodiment of the present invention.
The present embodiment adopts a configuration of opening/closing the cooling
water opening/closing apparatuses 172 not at a predetermined interval as in the case of the first
embodiment but while monitoring deviation between an actual value and a target value of a
coiling temperature (strip temperature).
As shown in Fig. 9, the hot rolling system 1A is constructed of a hot rolling
control device 100A and a control target 150. The hot rolling control device 1OO A is greatly
5 different from the hot rolling control device 100 in that a coiling temperature deviation
calculation section 90 1 and a coiling temperature control section 903 are provided instead of the
open mode interval storage section 107 and the closed mode interval storage section 108.
The coiling temperature deviation calculation section 901 calculates a deviation
ATc between a target coiling temperature Tc - target received from the host computer 50 via the
10 command receiving section 101 and an actual coiling temperature Tc - act received from the
coiling temperature pyrometer 155 via the data gathering section 102 according to equation (1).
The coiling temperature deviation calculation section 90 1 then outputs the calculated deviation
ATc to a table roll cooling water control section 902.
[Expression 11
15 ATc = Tc - act-Tc - target ... (1)
The coiling temperature control section 903 controls operations of the laminar
cooling apparatus 160 and the spray cooling apparatus 163 based on the deviation ATc calculated
by coiling temperature deviation calculation section 901. Note that the coiling temperature
control section 903 may be provided inside the control target 150.
20 Upon receiving a command for cooling control of the table roll 170 from the
command receiving section 101, the table roll cooling water control section 1 10 opens/closes the
cooling water opening/closing apparatuses 172 according to signals from the open mode start
timing determining section 103 and the closed mode start timing determining section 104. In
this case, the table roll cooling water control section 11 0 controls opening/closing of the cooling
25 water opening/closing apparatuses 172 using set values of the open mode priority storage section
105 and the closed mode priority storage section 106, and the deviation ATc calculated by the
coiling temperature deviation calculation section 901.
Fig. 10 is a flowchart illustrating processing executed by the table roll cooling
water control section 902.
30 First, the table roll cooling water control section 902 determines whether an open
mode start timing signal is received from the open mode start timing determining section 103 or
not (step S3 1).
Upon receiving the open mode start timing signal, the table roll cooling water
control section 902 outputs, to the table roll cooling apparatus 171, a signal to open each cooling

water opening/closing apparatus 172 according to the priority of each cooling water
opening/closing apparatus 172 corresponding to the steel grade and strip thickness of the strip
151 collected from the open mode priority storage section 105 (step S32).
Next, the table roll cooling water control section 902 determines whether all the
cooling water opening/closing apparatuses 172 have been opened or not (step S33). When all
the cooling water opening/closing apparatuses 172 have been opened, the opening processing
ends, and so the process moves to step S36.
When all the cooling water opening/closing apparatuses 172 have not been
opened, the table roll cooling water control section 902 determines whether a response time has
10 elapsed or not (step S34). The response time refers to a time required for an influence to appear
on the coiling temperature pyrometer 155 when a cooling water opening/closing apparatus 172 is
operated from a closed state to an open state, and is calculated using equation (2).
t = L/V+tO ,.. (2)
t: response time (s), V: strip speed (mls), to: temperature detection time by coiling
15 temperature pyrometer, L: distance (m) from cooling water opening/closing apparatus 172
operated from closed state to open state to coiling temperature pyrometer 155
when a plurality of cooling water opening/closing apparatuses 172 are operated,
distance from the cooling water opening/closing apparatus 172 farthest from the coiling
temperature pyrometer 155 to the coiling temperature pyrometer 155
When the response time has not elapsed, the table roll cooling water control
section 902 waits for the response time to elapse in step S34 and determines, when the response
time has elapsed, whether the deviation ATc of the coiling temperature is smaller than a tolerance
or not (step S35). The tolerance is, for example, *lo0.
In the present embodiment, the tolerance is a value associated with the strip 15 1.
25 Although the table roll cooling water control section 902 receives the tolerance from the host
computer 50 via the command receiving section 101, the tolerance may be stored as a constant in
a non-volatile memory (not shown) of the hot rolling control device 100. When the deviation
ATc is not smaller than the tolerance, the table roll cooling water control section 902 repeats the
determination processing in step S35. When the deviation ATc is smaller than the tolerance, the
30 table roll cooling water control section 902 returns to step S32 and performs processing of
opening the cooling water opening/closing apparatus 172 with the next priority. Hereinafter,
the processes in step S32 to step S35 will be repeated.
Next, when all the cooling water opening/closing apparatuses 172 have been
opened, the table roll cooling water control section 902 determines whether a closed mode start
- 18 -
timing signal is received from the closed mode start timing determining section 104 or not (step
S36).
Upon receiving the closed mode start timing signal, the table roll cooling water
control section 902 outputs, to the table roll cooling apparatus 171, a signal for closing the
5 cooling water opening/closing apparatus 172 according to priority of each cooling water
opening/closing apparatus 172 corresponding to the steel grade and strip thickness of the strip
15 1 collected from the closed mode priority storage section 106 (step S37).
Next, the table roll cooling water control section 902 determines whether all the
cooling water opening/closing apparatuses 172 have been closed or not (step S38). When all
10 the cooling water opening/closing apparatuses 172 have been closed, the processing of closing
the cooling water opening/closing apparatuses 172 ends, and so the processing on the strip 15 1
by the table roll cooling water control section 902 ends.
When all the cooling water opening/closing apparatuses 172 have not been
closed, the table roll cooling water control section 902 determines whether the response time has
15 elapsed or not (step S39). The response time may be calculated according to equation (2) as
with step S34.
When the response time has not elapsed, the table roll cooling water control
section 902 waits for the response time to elapse in step S34 and when the response time has
elapsed, the table roll cooling water control section 902 determines whether the coiling
20 temperature deviation ATc is smaller than a tolerance or not (step S40).
When the deviation ATc is not smaller than the tolerance, the table roll cooling
water control section 902 repeats the determination processing in step S40. When the deviation
ATc is smaller than the tolerance, the table roll cooling water control section 902 returns to step
S37 and performs processing of closing the cooling water opening/closing apparatus 172 with
25 the next priority. Hereinafter, the processes in step S37 to step S40 will be repeated.
In addition to the operations and effects of the first embodiment, the present
embodiment exerts the following effects.
The present embodiment controls the opening/closing of the cooling water
opening/closing apparatuses 172 while monitoring the deviation Atc between the actual value
30 and the target value of the coiling temperature, and it is thereby possible to control the
opening closing of the cooling water opening closing apparatuses 172 while confirming the
coiling temperature of the strip 15 1. Since the cooling water opening closing apparatuses 172
are opened closed by reflecting the actual state of the strip 15 1, it is possible to obtain a coiling
temperature with high accuracy in any region of the strip 15 1 in the strip length direction.
Note that in Fig. 10, processing of opening closing each cooling water
opening closing apparatus 172 is performed while monitoring the deviation between the actual
value and the target value of the coiling temperature, but such monitoring may be applied only
when each cooling water opening closing apparatus 172 is either opened or closed.
5 <3. Third embodiment>
A third embodiment of the present invention will describe an example where the
same priority is assigned to cooling water opening closing apparatus numbers as priority to be
stored in the open mode priority storage section 105 and the closed mode priority storage section
106. That is, in the present embodiment, a plurality of cooling water opening closing
10 apparatuses 172 are collectively opened closed at the same timing.
Fig. 11 is a diagram illustrating a configuration example of the open mode priority
storage section 105.
Fig. 11 shows an example of the open mode priority storage section 105 which
stores priority of each cooling water opening closing apparatus 172 when the cooling water
opening closing apparatus 172 is opened in association with the steel grade, strip thickness and
cooling water opening closing apparatus numbers 1 to 10. For example, when the steel grade is
SS400, strip thickness is 1.2 to 2.0 mm, #1, #2 and #3 are assigned the same value, that is, 3.
When the cooling water opening closing apparatuses 172 are opened under the control of the
table roll cooling water control section 902, the cooling water opening closing apparatuses 172
with the same priority are simultaneously opened.
Fig. 12 is a diagram illustrating a configuration example of the closed mode
priority storage section 106.
The closed mode priority storage section 106 stores priority of each cooling water
opening closing apparatus 172 when each cooling water opening closing apparatus 172 is closed
25 in association with the steel grade, strip thickness and the cooling water opening closing
apparatuses 172 of # 1 to # 10. For example, when the steel grade is DP-1, strip thickness is 1.2
to 2.0 mm, the cooling water opening closing apparatuses 172 of #2 and #3 are assigned the
same priority of 2. Similarly, when the cooling water opening closing apparatuses 172 are
closed under the control of the table roll cooling water control section 902, the cooling water
opening closing apparatuses 172 with the same priority are simultaneously closed.
In addition to the operations and effects of the first embodiment, the present
embodiment exerts the following effects. The present ernbodilnent can control opening/closing
of the cooling water opening closing apparatuses1 with the same priority simultaneously. It
is preferable to simultaneously open close a plurality of cooling water opening closing
apparatuses 172 from the perspective of coiling temperature control. The greater the strip
thickness of the strip 15 1, the smaller the temperature variation when cooling water is sprayed
and the smaller the influence of opening closing of the cooling water opening closing
apparatuses 172, and so the present embodiment is advantageous for control of a coiling
5 temperature of the strip 15 1 of greater strip thickness.
In the first or third embodiment, when at least each cooling water opening closing
apparatus 172 is opened, as long as a configuration is provided in which when control is
performed so as to open each cooling water opening closing apparatus 172 at time intervals that
10 satisfy a certain condition (priority for each steel grade or strip thickness or a relationship
between deviation of coiling temperature and tolerance), the order in which the respective
cooling water opening closing apparatuses 172 are closed may be order following the
aforementioned priority or any given order. For example, the respective cooling water
opening closing apparatuses 172 are sequentially opened according to priority, and when the
15 respective cooling water opening closing apparatuses 172 are closed, they may be closed
simultaneously.
The present invention is not limited to the above-described embodiments, but may
include other modifications or application examples without departing from the spirit and scope
of the present invention described in the appended claims. The present invention is widely
applicable to cooling control of a hot rolling coiling temperature control line.
For example, the above-described embodiments have been described in detail to
describe the present invention in an easily comprehensible way, and are not necessarily limited to
those provided with all the configurations described above. Moreover, some components of a
certain embodiment may be replaced by components of another embodiment or components of a
25 certain embodiment may be added to components of another embodiment. Some components
of each embodiment may be supplemented with or replaced by other components or deleted.
Furthermore, the control lines and information lines indicate those considered
necessary for description, and all such control lines and information lines are not necessarily
shown in the product. It is possible to assume that substantially all components are actually
30 connected to one another.
Moreover, part or a whole of each configuration, function or processing section or
the like described above may be implemented by hardware by designing them using, for
example, integrated circuits. Each configuration or function or the like described above may
also be implemeilted by software for a processor to interpret and execute a program that
implements the respective functions. Information such as a program, tables or files for
implementing each function can be stored in a recording device such as memory, hard disk, SSD
(solid state drive) or recording medium such as IC card, SD card or optical disk.
Fig. 13 is a block diagram illustrating a hardware configuration example of a
5 computer (e.g., personal computer) that executes the aforementioned series of processes
according to a program.
In the computer, a CPU 201, a ROM (Read Only Memory) 202 and a RAM 203
are connected to one another via a bus 204.
The bus 204 is further connected to an input output interface 205. The
10 input output interface 205 is connected to an input section 206 made up of a keyboard, mouse,
microphone or the like, an output section 207 made up of a display, speaker or the like, a
recording section 208 made up of a hard disk, non-volatile memory or the like and a
communication section 209 made up of a network interface or the like. The bus 204 is further
connected to a drive 2 10 that drives a removal medium 21 1 such as magnetic disk, optical disk,
15 magneto-optical disk or semiconductor memory.
In the computer configured as described above, the CPU 201 loads a program
stored, for example, in the recording section 208 into the RAM 203 via the inputloutput interface
205 and the bus 204 and executes the program to thereby perform the aforementioned series of
processes.
The program executed by the computer (CPU 20 1) is provided by being recorded
in the removal medium 2 11 which is a package medium made up of magnetic disk (including
flexible disk), optical disk (CD-ROM (Compact Disc-Read Only Memory), DVD (Digital
Versatl le Disc) or the like), magneto-optical disk or semiconductor memory or via a wired or
wireless transmission medium such as local area network, the Internet digital satellite
broadcasting.
The program can be installed in the recording section 208 via the input output
interface 205 by loading the removal medium 2 11 into the drive 21 0. The program can be
received by the communication section 209 via the wired or wireless transmission medium and
installed in the recording section 208. In addition, the program can also be installed beforehand
in the ROM 202 or recording section 208.
The program executed by the computer may be a program that is processed in
time sequence ill order described in the present specification or a program that is processed in
parallel or at necessary timing such as when it is invoked.
It should be further understood by those skilled in the art that although the
foregoing description has been made on embodiments of the invention, the invention is not
limited thereto and various changes and modifications may be made without departing from the
spirit of the invention and the scope of the appended claims.

WE CLAIM:
1. A hot rolling control device, comprising:
an open mode start timing determining section (1 03) that determines timing of
starting cooling of a plurality of table rolls (1 70) comprising a run-out table that conveys a strip
(151) rolled by a hot rolling machine (152) while cooling the strip (151) by a strip cooling
apparatus (160, 163) provided on a delivery side of the hot rolling machine (1 52), from position
information on a top end of the strip (151), for a table roll cooling apparatus (171) as a control
target provided with a plurality of cooling water opening closing apparatuses (172) arranged
along a flow direction of the strip (151) for the plurality of table rolls (170);
an open mode priority storage section (105) that opens the plurality of cooling
water opening closing apparatuses (172) when starting cooling of the plurality of table rolls
(170) and stores a first priority for discharging cooling water; and
a table roll cooling water control section (110) that performs control of opening
the plurality of cooling water opening closing apparatuses (172) at timing of starting the cooling
determined by the open mode start timing determining section (1 03) according to the first
priority collected from the open mode priority storage section (105) and at time intervals under a certain condition.
2. The hot rolling control device according to claim 1, further comprising:
a closed mode start timing determining section (1 04) that determines timing of
starting cooling end processing of the plurality of table rolls (170) from position information on a
tail end of the strip (151) collected from the control target; and
a closed mode priority storage section (106) that closes the plurality of cooling
water opening closing apparatuses (172) during cooling end processing on the plurality of table
rolls (170) and stores a second priority for stopping discharge of the cooling water,
wherein the table roll cooling water control section (110) performs control of
closing the plurality of cooling water opening closing apparatuses (172) at timing of starting the cooling end processing determined by the closed mode start timing determining section (1 04),
according to the second priority collected from the closed mode priority storage section (1 06)
and at time intervals under a certain condition.
3. The hot rolling control device according to claim 2, wherein a time after a cooling
water opening closing apparatus (172) is opened based on the first priority until another cooling
water opening closing apparatus (172) with the next priority is opened and a time after a cooling
water opening closing apparatus (172) is closed based on the second priority until another
cooling water opening closing apparatus (172) with the next priority is closed are predetermined
as the time interval under a certain condition.
4. The hot rolling control device according to claim 2, wherein the time interval
under a certain condition is a time until a deviation between a coiling temperature of the strip
(151) and a target value becomes smaller than a tolerance.
5. The hot rolling control device according to claim 2, wherein the open mode
priority storage section (105) stores order in which the plurality of cooling water opening/closing
apparatuses (172) stratified according to one or more pieces of strip information including at
least a steel grade or strip thickness of the strip (151) are opened and the closed mode priority
storage section (106) stores order in which the plurality of cooling water openinglclosing
apparatuses (172) stratified according to one or more pieces of strip information including at
least the steel grade or strip thickness of the strip (151) are closed.
6. The hot rolling control device according to claim 3, wherein a time after a cooling
water openinglclosing apparatus (172) is opened based on the first priority until another cooling
water openinglclosing apparatus (172) with the next priority is opened and a time after a cooling
water openinglclosing apparatus (172) is closed based on the second priority until another
cooling water openinglclosing apparatus (172) with the next priority is closed are stratified
according to one or more pieces of strip information including at least the steel grade or strip
thickness of the strip (151).
7. A hot rolling control method comprising:
determining, by an open mode start timing determining section (1 03), timing of
starting cooling of a plurality of table rolls (170) cooled by a table roll cooling apparatus (171)
provided with a plurality of cooling water opening/closing apparatuses (1 72) arranged along a flow direction of a strip (1 5 I), from position information on a top end of the rolled strip (151) in a cooling process, the strip (1 5 1) being rolled and conveyed on a run-out table comprising the
plurality of table rolls (1 70); and
opening, by a table roll cooling water control section (11O), the plurality of
cooling water openinglclosing apparatuses (172) at the timing of starting cooling determined by
the open mode start timing determining section (1 03) according to priority for discharging
cooling water by opening the plurality of cooling water opening/closing apparatuses (172) when
starting cooling of the plurality of table rolls (170) stored in the open mode priority storage
section (105) and at a time interval under a certain condition.