1. A rolled strip coiling temperature control apparatus comprising: a header openlclose pattern output unit configured to output a header openlclose pattern of data for instructing a plurality of cooling headers to open or 5 close, the plurality of cooling headers installed along a length direction of a rolled strip and between a rolling mill and a rolled strip coiling machine for coiling the rolled strip that is rolled by the rolling mill, an openlclose pattern preset unit configured to set the openlclose pattern for each of control sections of the rolled strip into which the rolled strip is 10 partitioned in the length direction of the rolled strip, each of the control sections having a predetermined length in the length direction of the rolled strip, a coiling temperature collection unit for collecting temperatures on the rolled strip being coiled by the rolled strip coiling machine, and a header response delay calculation unit configured to calculate a shift 15 length in the length direction of the rolled strip, the shift length by which previous measured length direction coiling temperatures collected by the coiling temperature collection unit of the rolled strip previously rolled shift from target length direction coiling temperatures that are set in advance for the rolled strip and calculate a header response delay time based on the shift length and a rolled 20 strip, running speed, wherein the header openlclose pattern output unit outputs the header openlclose pattern to the plurality of cooling headers at a time the calculated header response delay time before the control section of the rolled strip that is associated with the header openlclose pattern to be output arrives at a position 25 where the cooling header to which the header openlclose pattern is output is installed.

2. The rolled strip coiling temperature control apparatus as described in claim 1, wherein the header response delay calculation unit is configured to 30 calculate a correlation coefficient between the measured length direction coiling temperatures and the target length direction coiling temperatures both on either a front, end portion or a tail end portion of t.he rolled strip every time either the measured length direction coiling temperatures or the target length direction 27 coiling temperatures are shifted forward or rearward, obtain a shift length at which the correlation coefficient is maximum, the shift length by which the measured length direction coiling temperatures shift from the target length direction coiling temperatures, and calculate the header response delay time. 5

3. The rolled strip coiling temperature control apparatus as described in claim 1, wherein the header response delay calculation unit obtains a header open response delay time for the header response delay time used when an instruction is output to the cooling header to open based on the measured length direction 10 coiling temperatures and the target length direction coiling temperatures on a front end portion of the rolled strip, and obtains the header close response delay time for the header response delay time used when an instruction is output to the cooling header to close based on the measured length direction coiling temperatures and the target length direction coiling temperatures on a tail end 15 portion of the rolled strip.

4. The rolled strip coiling temperature control apparatus as described in claim 3, wherein the header openlclose pattern output unit outputs the header openlclose pattern to the cooling headers to open at a first timing and to the other 20 cooling headers to close at a second timing is independent of the first timing.

5. A method for controlling a coiling temperature of a rolled strip to be cooled with cooling water discharged out of a plurality of cooling headers installed along a length direction of a rolled strip and between a rolling mill and a rolled 25 strip coiling machine to coil the rolled strip that is rolled by the rolling mill, the method comprising steps by a control device to control the plurality of cooling headers, an openlclose pattern preset step of setting a header openlclose pattern of data for instructing the plurality of cooling headers to open or close for each of 30 control sections of the rolled strip into which the rolled strip is partitioned in the length direction of the rolled strip, each of the control sections having a predetermined length in the lengt,h direct,ion of the rolled strip, 28 a coiling temperature collection step of collecting temperatures on the rolled strip being coiled by the rolled strip coiling machine, a header response delay calculation step of calculating a shift length in the length direction of the rolled strip, the shift length by which previous 5 measured length direction coiling temperatures that are collected by the coiling temperature collection step of the rolled strip previously rolled shift from target length direction coiling temperatures that is set in advance for the rolled strip, and calculating a header response delay time based on the shift length and a rolled strip running speed, and 10 a header openlclose pattern output step of outputting the header openlclose pattern to the plurality of cooling headers at a time the calculated header response delay time before the control section of the rolled strip that is associated with the header openlclose pattern to be output arrives at a position where the cooling header to which the header openlclose pattern is output is 15 installed.

6. The method for controlling a coiling temperature of a rolled strip as described in claim 5, wherein the control device calculates a correlation coefficient between the measured length direction coiling temperatures and the target length 20 direction coiling temperatures both on either a front end portion or a tail end portion of the rolled strip every time either the measured length direction coiling temperatures or the target length direction coiling temperatures are shifted forward or rearward, obtain a shift length at which the correlation coefficient is maximum and calculate, the shift length by which the measured length direction 25 coiling temperatures shift from the target length direction coiling temperatures, and calculate the header response delay time in the header response delay calculation step.

7. The method for controlling a coiling temperature of a rolled strip as 30 described in claim 5, wherein the control device obtains a header open response delay time for the header response delay time used when an instruction is output to the cooling header to open based on the measured length direction coiling temperatures and the target length direction coiling temperatures on a front end 29 portion of the rolled strip, and obtains a header close response delay time for the header response delay time used when an instruction is output to the cooling header to close based on the measured length direction coiling temperatures and the target length direction coiling temperatures on a tail end portion of the rolled 5 strip.

8. The method for controlling a coiling temperature of a rolled strip as described in claim 7, wherein the control device outputs the header openlclose pattern to the cooling headers to open at a first timing and to the other cooling 10 headers to close at a second timing is independent of the first timing.

Rolled Strip Coiling Temperature Control Apparatus and Method for Controlling
Rolled Strip Coiling Temperature
BACKGROUND OF THE INVENTION
5 [0001] The present invention relates to a rolled strip coiling temperature
control apparatus used in a rolling line for rolled strips such as rolled steel strip
and a method for controlling a rolled strip coiling temperature.
DESCRIPTION OF THE RELATED ART
10 [0002] JPH07-16635A and JPH08-168804A disclose techniques to control a
temperature of a rolled strip when the rolled strip is rolled in a rolling line to be a
target temperature. For example, according to JPH07-16635A, while a speed and
a temperature of the rolled strip are being measured at each position of an exit
side of a rolling mill and a coiling machine, a cooling bank pattern is determined
15 at a predetermined interval according to the measurement data, the coiling
temperature is controlled while the rolled strip is being cooled by cooling based on
the determined cooling bank pattern. In this case, the cooling bank pattern by
which the rolled strip is to be cooled is dynamically changed in response to the
speed and the temperature of the rolled strip at which the rolled strip is rolled
20 and coiled, which enables accurate control of the coiling temperature of the rolled
strip when the speed of the rolled strip is varying.
[0003] JPH08-168804A describes that while the speed of the rolled strip is
predicted at the cooling bank position based on parameters such as the finishing
rolling speed in order to ensure that the coiling temperature is accurately
25 controlled even when the rolling speed varies according to a predetermined
pattern, an cooling flow rate, a cooling bank pattern and a timing for opening and
closing a cooling bank, which are appropriate, are calculated based on the
predicted strip speed and such measured data as rolling strip's temperature and
thickness at the finishing rolling delivery side.
30 [0004] A delay time from when the cooling bank receives an instruction to
start cooling to when a predetermined cooling effect starts to appear after a
cooling water valve is made t,o open and cooling water starts to flow out from
through cooling headers and the cooling water at a predetermined flow rate starts
3
to come in contact with the rolled strip is often referred to as a cooling header
response delay time (or a response delay). In general, this cooling header
response delay time gradually varies as time elapses due to changes in an amount
of water or a water level of the cooling water tank and does not stay constant.
5 [0005] JPH07-16635A and JPH08-168804A disclose techniques to control the
coiling temperature in which this cooling header response delay time is somewhat
considered. However, neither of these prior documents takes it into consideration
that this cooling header response delay time gradually changes as time elapses
and both of these prior documents assume that this cooling header response delay
10 time stays constant. Therefore, when the cooling header response delay time
changes, a start timing for cooling the rolled strip becomes earlier or later than it
should be. As a result, the control of the coiling temperature of the rolled strip is
not accurately performed.
[0006] Taking account of problems with the current techniques, the present
15 invention is intended to provide a rolled strip coiling temperature control
apparatus and a method for controlling a rolled strip coiling temperature which
enable accurately controlling the coiling temperature of the rolled strip even when
the cooling header response delay time changes as time elapses.
20 SUMMARY OF THE INVENTION
[0007] A rolled strip coiling temperature control apparatus of the present
invention comprises, a header open/close pattern output unit configured to output
a header openlclose pattern of data for instructing a plurality of cooling headers to
open or close, the plurality of cooling headers installed along a length direction of
25 a rolled strip and between a rolling mill and a rolled strip coiling machine for
coiling the rolled strip that is rolled by the rolling mill, an open/close pattern
preset unit configured to set the open/close pattern for each of control sections of
the rolled strip into which the rolled strip is partitioned in the length direction of
the rolled strip, each of the control sections having a predetermined length in the
30 length direction of the rolled strip, a coiling temperature collection unit for
collecting temperatures on the rolled strip being coiled by the rolled strip coiling
machine, and a header response delay calculation unit configured to calculate a
shift length in the length direction of the rolled strip, the shift length by which
4
previous measured length direction coiling temperatures collected by the coiling
temperature collection unit of the rolled strip previously rolled shift from target
length direction coiling temperatures that is set in advance for the rolled strip
and a header response delay time based on the shift length and a rolled strip
5 running speed. This rolled strip coiling temperature control apparatus has a
feature of the header openlclose pattern output unit outputting the header
openlclose pattern to the plurality of cooling headers at a time the calculated
header response delay time before the control section of the rolled strip that is
associated with the header openlclose pattern to be output arrives at a position
10 where the cooling header to which the header openlclose pattern is output is
installed.
[0008] The present invention provides a rolled strip coiling temperature
control apparatus and a method for controlling a coiling temperature of a rolled
strip which enable controlling the coiling temperature of the rolled strip with high
15 accuracy, if the header response delay time changes with time elapsing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Fig.1 schematically shows a configuration of a rolled strip coiling
temperature control apparatus according to an embodiment of the present
20 invention and a rolled strip coiling temperature control line to be controlled by
the apparatus.
Fig.2 shows an example of a set of target coiling temperature data for
various types of steel stored in a target coiling temperature storage section.
Fig.3 shows an example of U-pattern data for various types of steel
25 stored in a U-pattern data storage section.
Fig.4 shows an example of a length direction temperature profile for a
target length direction coiling temperature to be determined based on the Upattern
data.
Fig.5 shows an example of a set of target length direction coiling
30 temperature data on a rolled strip data stored in a target length direction coiling
temperature storage section.
Fig.6 shows an example of a set of header openlclose pattern data
stored in a header openlclose pattern storage section.
Fig.7 shows an example of a set of previous measured length direction
coiling temperature data 141a stored in a previous measured length direction
coiling temperature storage section.
Fig.8 shows an example of measured length direction temperatures of
5 length direction coiling temperatures relative to target length direction
temperatures.
Fig.9 shows an example of a set of previous measured rolling data
stored in a previous measured rolling data storage section.
Fig.10 shows a first example (Case 1) of a relation between the
10 previous measured length direction coiling temperature and the target length
direction coiling temperature for a front end portion of a rolled strip.
Fig.11 shows a second example (Case 2) of a relation between the
previous measured length direction coiling temperature and the target length
direction coiling temperature for a front end portion of a rolled strip.
15 Fig.12 shows an example of a flowchart of process steps performed by a
header opening response delay calculation unit when a header opening response
delay time is relatively long.
Fig.13 shows an example of a flowchart of process steps performed by a
header openlclose pattern output unit.
20 Fig.14 shows an example of target length direction temperatures when
non-cooling regions are set in a front end and a tail end portions of a rolled strip
instead of U-pattern regions.
Fig.15 shows an example of target length direction temperatures when
non-cooling regions are set in parts of front end and tail end portions of a rolled
25 strip while U-pattern regions are set in the rest of the front end and tail end
portions of the rolled strip.
Fig.16 shows an example of data of header open response delay times
which are classified and stored in a header open response delay storage section.
3 0 DETAILED DESCRIPTION OF THE EMBODIMENT
[0010] Hereinafter, embodiments to practice the invention of the present
application are explained in detail with reference to drawings attached.
6
[0011] Fig.1 schematically shows a configuration of a rolled strip coiling
temperature control apparatus 100 according to an embodiment of the present
invention and a rolled strip coiling temperature control line 150 to be controlled
by the rolled strip coiling temperature control apparatus 100. To begin with, a
5 general configuration of the rolled strip coiling temperature control line 150 is
explained.
[0012] As shown in Fig.1, the rolled strip coiling temperature control line 150
is configured to comprise a cooling machine 153 for cooling to a predetermined
temperature a strip 151 (rolled strip) that is at a temperature approximately
10 between 900 "C and 1000 "C after being rolled through a rolling mill 152, a downcoiler
159 (rolled strip coiling machine) for coiling the cooled rolled strip 151 and a
coiling temperature sensor 158 for measuring a temperature on the strip 151
immediately before it is coiled.
[0013] The cooling machine 153 consists of an upper cooling machine 154 to
15 cool the rolled strip 151 from its upper surface and a lower cooling machine 155 to
cool the rolled strip 151 from its lower surface. There are plural banks 156 (for
example, 15 banks 156) which are attached to each of the upper cooling machine
154 and the lower cooling machine 155 and arranged along the length direction
(that is, running direction) of the rolled strip. There are plural cooling headers
20 157 attached to each bank 156 (for example, seven rows arranged in the length
direction of the strip 151 and each row consists of 10 cooling headers 157
arranged along the width direction of the strip 151). Cooling water with a
predetermined flow rate and a predetermined water pressure is discharged out of
each of the cooling headers157 according to an instruction from the rolled strip
25 coiling temperature control apparatus 100.
[0014] The coiling temperature sensor 158 is disposed between the cooling
machine 153 and the down-coiler 159 and intended to measure the temperature
on the rolled strip 151 to be coiled about the down-coiler 159. The rolled strip
coiling temperature control apparatus 100 controls each of the cooling headers
30 157 to have cooling water start or stop being discharged out of each of the cooling
headers 157 in such a way that a coiling temperature of the strip 151 measured
by the coiling temperature sensor 158 is equal t,o a tal'get, coiling t,emperat,ure.
The target coiling temperature may be constant over the strip 151 in the length
direction or differ between various portions of the strip 151.
[0015] Next is explained a configuration of the rolled strip coiling temperature
apparatus 100. As shown in Fig.1, the rolled strip coiling temperature apparatus
5 100 is configured to comprise various process function units such as a preset unit
110 to set initial control values of the header openlclose patterns of the cooling
headers 157 and the target coiling temperatures, a rolling data collection unit 136
to collect various rolling data in the rolling process, a coiling temperature
collection unit 140 to collect coiling temperatures measured by the coiling
10 temperature sensor 158, a header open response delay time calculation unit 131
to calculate a header open response delay time, a header close response delay
time calculation unit 133 to calculate a header close response delay time, and a
header openlclose pattern output unit 135 to output the openlclose pattern of each
of the cooling headers 157 to the cooling machine 153. In addition, the rolled strip
15 coiling temperature apparatus 100 comprises several storage sections such as a
measured rolling data storage unit 137, a measured length direction coiling
temperature storage section 141, a header open response delay storage section
132 and a header close response delay storage section 134.
[0016] The preset unit 110 comprises such process function units as a target
20 length direction coiling temperature determination unit 111 and an openlclose
pattern preset unit 112 and such memory sections as a strip temperature
estimation model 113, a target coiling temperature storage section 114, a Upattern
storage section 115, a target length direction coiling temperature storage
section 116 and a header openlclose pattern storage section 117.
25 [0017] The target length direction coiling temperature determination unit 11 1
of the preset unit 110 determines the target coiling temperature data set along
the length direction (refer to Fig.5) of the strip 151 to be cooled based on the
target coiling temperature data (refer to Fig.2) stored in advance in the target
coiling temperature storage section 114 and the U-pattern data (refer to Fig.3)
30 stored in advance in the U-pattern storage section 115. In order to have the
coiling temperature of the strip 151 equal to the target coiling temperature, the
openlclose pattern preset unit 112 calculates in advance a header openlclose
pattern for each of the cooling headers 157 in each of the controlled sections into
8
which the rolled strip is divided and disposed in its length direction by performing
calculation based on the strip temperature estimation model 113.
[0018] Fig.2 shows an example of a set of target coiling temperature data for
various types of steel stored in the target coiling temperature storage section 114.
5 As shown in Fig.2, the target coiling temperature data include target coiling
temperatures and steel types (kind of strip) and an appropriate coiling
temperature is associated with each of the steel types. Accordingly the target
length direction coiling temperature determination unit 111 determines a steel
type of the strip 151 to be cooled and pick up a target coiling temperature (To)
10 associated with the determined steel type with reference to the target coiling
temperature storage section 114.
[0019] Fig.3 shows an example of U-pattern data for various types of steel
stored in the U-pattern data storage section 115. Fig.4 shows an example of a
length direction temperature profile for a target length direction coiling
15 temperature to be determined based on the U-pattern data. Fig.5 shows an
example of a set of target length direction coiling temperature data on a rolled
strip data stored in a target length direction coiling temperature storage section
116.
[00201 In these figures, the U-pattern refers to a coiling temperature pattern
20 in which the target length direction coiling temperature is set higher than the
target coiling temperature (To) obtained from the target coiling temperature
storage section 114 in each of the front end and tail end portions of the strip 151,
each of which is between several meters long and several tens of meters long, in
order to improve a property of the strip 151 for getting coiled about the down
25 coiler 159.
[00211 For example, a set of the U-pattern data includes such data as a steel
type, a strip thickness, a strip width, a temperature correction degree (AT1) over
the front end portion of the strip, a length of the front end portion of the strip, a
temperature correction degree (AT2) over the tail end portion of the strip, a
30 length of the tail end portion of the strip. The temperature correction amounts
(ATI, AT2) referred to in Fig.3 indicate temperature correction amounts
respectively in the front end and tail end portions of the strip 151, as indicated in
9
Fig.4. Lengths (Ll, L2) represent respectively lengths of temperature correction
portions in the front end and tail end portions of the strip 151 where temperature
correction is made.
[0022] As the target coiling temperature obtained from the target coiling
5 temperature storage section 114 is To, the target coiling temperature set for the
temperature compensation region in the front end portion of the strip 151 is
represented by a function of the corrected target coiling temperature that
gradually decreases from To+ATl to To (Usually a linear function). In addition,
the target coiling temperature set for the temperature correction portion in the
10 tail end portion of the strip 151 is represented by a function of the corrected
target coiling temperature that gradually increases from To to To+ATz (Usually a
linear function).
[00231 Accordingly, for example, when the strip 151 to be cooled is of a steel
type of SPHC (hot-rolled low-carbon steel) and has a width 1250mm long and a
15 thickness 3.5mm, the target length direction coiling temperature determination
unit 111 refers to the target coiling temperature storage section 114 (Fig.2) and
the U-pattern storage section 115 (Fig.3) and obtains a target coiling temperature
(600°C), a temperature correction degree (40°C) and a length (20m) of the
temperature correction portion in the front end portion of the strip 151 and a
20 temperature correction degree (50°C) and a length (25m) of the temperature
correction portion in the tail end portion of the strip 151, which are associated
with the steel type, . Moreover, the target length direction coiling temperature
determination unit 111 creates data of target length direction coiling
temperatures according to the obtained data and stores the created data of target
25 length direction coiling temperatures in the target length direction coiling
temperature storage section 116.
[0024] Looking at the target length direction coiling temperature data as
shown in Fig.5, target length direction coiling temperatures are set at intervals of
one meter. Accordingly, the target coiling temperature of 640°C is set at a first
30 position one meter away from the front end of the strip 151 and the target coiling
temperature becomes gradually lower from the first position to a second position
20m away from the front end, at which the target coiling temperature is 600°C.
The target coiling temperature stays constant from the second position to a third
10
position 975m away from the front end (25m away from the tail end). The target
coiling temperature becomes gradually higher from the third position to a fourth
position lOOOm away from the front end, that is, the tail end, at which the target
coiling temperature is 650°C.
5 [00251 Fig.6 shows an example of a set of header openlclose pattern data
stored in a header openlclose pattern storage section 117. As shown in Fig.6, the
header openlclose pattern data consist of data corresponding to instructions to the
headers 157 of the banks 156 for each of control sections of a strip into which the
strip is sectioned every 5m along the length direction. Each of the data is either 1
10 or 0. "I" corresponds to an instruction to open a row of headers and "0"
corresponds to an instruction to close the row of headers. This header openlclose
pattern data is calculated by the header openlclose preset unit 112 and stored in
the header openlclose pattern storage section 117.
[0026] Fig.7 shows an example of a set of previous measured length direction
15 coiling temperature data 141a stored in a measured length direction coiling
temperature storage section 141. As shown in Fig.7, the previous measured
length direction coiling temperature data 141a is configured to include coiling
temperatures measured, for example, at intervals of one meter on a strip 151
rolled in the previous rolling process by the coiling temperature sensor 158 and
20 obtained by the coiling temperature collection unit 140.
[0027] The coiling temperature collection unit 140 obtains coiling
temperatures of the strip 151 measured by the coiling temperature sensor 158 in
real time when a strip 151 being rolled is coiled about the down coiler 159.
Whenever a coiling temperature is obtained, the obtained coiling temperature is
25 associated with a position (length from the front end) at which the obtained
coiling temperature was measured and stored in the measured length direction
coiling temperature storage section 141. Therefore, the previous measured length
direction coiling temperature data 141a should be measured length direction
coiling temperatures already stored in the measured length direction coiling
30 temperature storage section 141 on a strip that was previously rolled.
[0028] Fig.8 shows an example of a length direction temperature profile of
length direction coiling temperatures relative to a target, length dii-ection
temperature profile. In the case of Fig.8, the measured length direction coiling
I1
temperature is higher in the front end portion and lower in the tail end portion
than the target length direction coiling temperature showing a U-pattern.
[0029] Fig.9 shows an example of a set of previous measured rolling data 137a
stored in the measured rolling data storage section 137. As shown in Fig.9, the
5 previous measured rolling data 137a consist of measured data such as strip
speeds which are measured at intervals of one meter on a strip rolled in the
previous rolling process and obtained by the rolling data collection unit 136.
[0030] The rolling data collection unit 136 collects in real time a length from
the front end to a delivery position of a strip being rolled (hereinafter called
10 "measured rolled out length") and a strip speed, both of which are measured at
the delivery position of a rolling mill. The length from the front end and the strip
speed are associated with each other and stored in the measured rolling data
storage section 137. Accordingly, the previous measured rolling data 137a should
correspond to measured rolling data which are collected on the strip 151 rolled in
15 the previous rolling process and stored in the measured rolling data storage
section 137.
[0031] Referring back to Fig.1, the detailed explanation of an embodiment
continues. As is explained, the header response delay of the cooling header 157
gradually changes as time goes by, due to a remaining water amount and a water
20 level of a cooling water tank (not shown in Fig.l). Therefore each of the header
open response delay time calculation unit 131 and the header close response delay
ti~neca lculation unit 133 calculates a length of a strip 151 in its length direction
that corresponds to a shift amount of the previous measured length direction
coiling temperature 141a stored in the measured length direction coiling
25 temperature storage section 141 from the target length direction coiling
temperature stored in the target length direction coiling temperature storage
section 116. As is explained below in detail, for example, when either the
previous length direction coiling temperature 141a or the target length direction
coiling temperature is gradually shifted forward or rearward, there is a shift
30 length at which both temperatures have a maximum correlation coefficient and
this shift length may be a shift amount between the previous measured length
direction temperature and the target length direction ternperat,urcl.
12
[0032] The header open response delay time calculation unit 131 and the
header close response delay time calculation unit 133 divide the shift amount
(shift length) calculated the way as above mentioned by the strip speed and
obtain respectively the header open delay time and the header close delay time of
5 the cooling header 157.
[0033] The header open response delay time calculation unit 131 calculates
the header open response delay time and stores it in the header open response
delay storage section 132 (to be explained in details below), making use of the
target length direction coiling temperature stored in the target length direction
10 coiling temperature storage section 116, the previous measured length direction
coiling temperature 141a stored in the measured length direction coiling
temperature storage section 141 and the strip speed which is stored in the
measured rolling data storage unit 137 and measured rolling data.
The header open response delay time corresponds to a time from when
15 the header openlclose pattern output unit 135 outputs to the cooling headers 157
an instruction to open for cooling water being discharged to when cooling water
starts to be discharged at a predetermined flow rate from the cooling headers 157
and the cooling effect on the strip starts to appear.
[0034] The header close response delay time calculation unit 133 calculates
20 the header close response delay time and stores it in the header close response
delay storage section 134, making use of the target length direction coiling
temperature stored in the target length direction coiling temperature storage
section 116, the previous measured length direction coiling temperature data
141a stored in the measured length direction coiling temperature storage section
25 141 and the strip speed which is stored in the measured rolling data storage unit
137 and measured rolling data.
The header close response delay time corresponds to a time from when
the header openlclose pattern output unit 135 outputs to the cooling headers 157
an instruction to close for when the cooling effect on the strip starts to disappear
30 after cooling water stops to be discharged from the cooling headers 157.
LO0351 The header openlclose pattern output unit 135 calculates a time at
which each of the control sections into which a strip 151 is sectioned in the length
direction of the strip 151 arrives just under the cooling headers 157, based on the
13
measured rolled out length of the strip being rolled (length from a delivery side
position of the rolling mill 152 to the front end of the strip) that is collected by the
rolling data collection unit 136 and a strip moving speed.
[0036] The header openlclose pattern output unit 135 obtains refers to the
5 header openlclose pattern storage section 117 and obtains a header open1 close
pattern associated with each control section of the strip 151 arriving just below
the cooling headers 157. The header openlclose pattern output unit 135 outputs
the obtained header openlclose pattern to the cooling headers 157 at a
predetermined time which is either the header open response delay time stored in
10 the header open response delay storage 132 or the header close response delay
time stored in the header close response delay storage section 134 before the time
at which each of the control sections of the strip 151 comes just under the cooling
headers 157.
Lo0371 Next the response delay times of cooling headers 157 (header open
15 response delay time and header close response delay time) are explained in detail.
Fig.10 shows a first example (Case 1) of a relation between a previous
measured length direction coiling temperature 141a and a target length direction
coiling temperature for a front end portion of a rolled strip 151. Fig.ll shows a
second example (Case 2) of a relation between a previous measured length
20 direction coiling temperature 141a and a target length direction coiling
temperature for a front end portion of a rolled strip 151.
[0038] The first example in Fig.10 (Case 1) indicates that since the previous
measured length direction coiling temperature 141a is higher than the target
length direction coiling temperature in the U-pattern region of the strip 151 (a
25 region within a length of LI from the front end of the strip 1511, the measured
length direction coiling temperature becomes equal to an original target length
direction coiling temperature (To) which is set without taking the U-pattern into
consideration at a position outside the U-pattern region, that is, more than the
length L1 away from the front end of the strip 151.
3 0 This indicates that the cooling effect appears later than it should
because the header open response delay time after an instruction to open cooling
headers 157 is output is set longer than needed.
14
[0039] On the other hand, the second example (Case 2) in Fig.11 indicates
that since the previous measured length direction coiling temperature 141a is
lower than the target length direction coiling temperature in the U-pattern region
of the strip 151 (a region within a length of L1 from the front end of the strip 151),
5 the previous measured length direction coiling temperature 141a becomes equal
to an original target length direction coiling temperature (To) which is set without
taking the U-pattern into consideration at a position inside the U-pattern region,
that is, less than the length L1 away from the front end of the strip 151 (origin
point shown in Fig.11).
10 This indicates that the cooling effect appears earlier than it should
because the header open response delay time after an instruction to open cooling
headers 157 is output is set shorter than needed.
[0040] A calculation method for the header response delay time is explained
with reference to Fig.10 and Fig.11. In principle, the header open response delay
15 time is obtained as follows. The previous measured length direction coiling
temperatures 141a are shifted forward or rearward by a small unit length at a
time. Each time the previous measured length direction coiling temperatures
141a are shifted, a correlation between the previous measured length direction
coiling temperatures 141a and the target length direction coiling temperatures is
20 calculated. A shift length, which is equal to a sum of the small unit lengths the
previous measured length direction coiling temperatures 141a have been shifted
and at which the calculated correlation is maximum, is obtained. This shift
length is converted to a shift time for the strip 151 having moved. This converted
shift time corresponds to the header open response delay time.
25 [0041] For example, the header open response delay time is specifically
obtained in the following way in Case 1 as shown in Fig.10. Firstly, a target
coiling temperature set is extracted which consists of the target length direction
coiling temperatures of a first portion of the strip 151 that is 2L1 long from the
front end of the strip 151, and a first measured coiling temperature set is
30 extracted which consists of the previous measured length direction coiling
temperatures 141a of the first portion of the strip 151 that is 2L1 long from the
front end of the strip 151. Then a correlation between the target coiling
temperature set and the first coiling measured temperature set is calculated.
15
Secondly, a second measured coiling temperature set is extracted which consists
of the previous measured length direction coiling temperatures 141a of the second
portion of the strip 151 that is 2L1 long from a first position that is lm rearward
from the front end of the strip 151. Then a correlation between the target coiling
5 temperature set and the second measured length direction coiling temperature
set is calculated. Thirdly a third measured coiling temperature set is extracted
which consists of the previous measured length direction coiling temperatures
141a of the third portion of the strip 151 2L1 long from a second position that is
lm rearward from the first position of the strip 151. This process is repeated to
10 obtain correlations between the target coiling temperature set and the measured
coiling temperature sets for the 2L1 long portions of the strip 151 which are
shifted by increments of lm from the front end of the strip 151. The header open
response delay time is calculated by determining a shift length by which the strip
151 having moved from the front end of the strip 151 and at which the correlation
15 between the target coiling temperature set and the measured temperature set is
maximum and converting this shift length to a shift time for which the strip 151
having moved. This converted shift time corresponds to the header open response
delay time.
[0042] In Case 2 as described in Fig. 11, the previous measured length
20 direction coiling temperature becomes lower than the target coiling temperature
(TO) at a position that is a length 11 rearward from the front end of the strip 151.
In this case, firstly a measured length direction coiling temperature set is
extracted which consists of the previous measured length direction coiling
temperatures 141a of the first portion of the strip 151 that is 211 long from the
25 front end of the strip 151, and a first target length direction coiling temperature
set of the target length direction coiling temperatures of the first portion of the
strip 151 that is 211 long from the front end of the strip 151 is extracted. Then a
correlation between the measured length direction coiling temperature set and
the first target length direction coiling temperature set is calculated. Secondly a
30 second target length direction coiling temperature set is extracted which consists
of the target length direction coiling temperatures of the second portion of the
strip 151 that is 211 long from a first, position I m rearward from the front end of
the strip 151. Then a correlation between the second target length direction
16
coiling temperature set and the measured length direction coiling temperature set
is calculated. Thirdly a third target length direction coiling temperature set is
extracted which consists of the target length direction coiling temperatures of the
third portion of the strip 151 that is 211 long from a second position lm rearward
5 from the first position of the strip 151. This process is repeated to obtain
correlations between the measured coiling temperature set and the target coiling
temperature sets for the 211 long portions of the strip 151 each of which is shifted
by increments of lm from the front end of the strip 151. The header open
response delay time is calculated by determining a shift length by which the strip
10 151 having moved from the front end of the strip 151 and at which the correlation
between the target coiling temperature set and the measured temperature set is
maximum and converting this shift length to a shift time for which the strip 151
having moved. This converted shift time corresponds to the header open response
delay time that has a negative value.
15 LO0431 The calculation method for the header open response delay time in
Case 2 corresponds to the calculation method in Case 1 in which the target length
direction coiling temperature is exchanged for the previous measured coiling
temperature 141a.
Lo0441 Fig.12 shows an example of a flowchart of process steps performed by
20 the header open response delay calculation unit 131 when the header open
response delay time is relatively long (Casel). In this example of the flowchart,
the header open response delay time is calculated according to the method
indicated in Fig.10 and a simple learning effect is added.
[0045] As indicated in Fig.12, the header open response delay time calculation
25 unit 131 firstly resets a variable number k to 0 (Step S11). This variable number
k is associated with a shift length by which a range of the previous measured
length direction coiling temperatures 141a is shifted rearward when the
correlation between the target length direction coiling temperatures and the
previous measured length direction coiling temperatures 141a is calculated (See
30 Fig.10).
[0046] Next, the header open response delay time calculation unit 131
ext,ract,s target lengt,h direction coiling temperatures (Tt,t ( i ) : i = 1 , 2 , - - - ,2L1) and
previous measured coiling temperatures ( T m o (j) ; j = 1 + k, 2 + k, ---,2 L1 + k) and
17
calculates a correlation coefficient between them according to the following
equation (1):
Corr ( k ) = Cov (Ttgt (i),T act (j )) I -\Iv ( ~ t(i~)). tV ( Tact( j))
Where Cov (Ttgt (i),T act (j )) is a covariance of Ttgt (i) and Tact (j ) ,
V (Ttgt (i)) is a variance of Ttgt (i) , and
V (Tact (i)) is a variance ofTact(i)
[0047] Next, if the variable number k (number of reiteration) is not equal to 0
10 ("No" in Step S13), the header open response time delay calculation unit 131
compares the correlation coefficient Corr (k) just obtained in Step S12 with the
correlation coefficient Corr (k- 1) obtained in the previous reiteration step and
determines which is larger between these correlation coefficients (Step S14).
[0048] Alternatively, if the variable number k (number of reiteration) is equal
15 to 0 ("Yes" in Step S13) or the header open response delay time calculation unit
131 determines that the correlation coefficient Corr (k) obtained this time is
larger than the correlation coefficient Corr (k-1) obtained in the previous time
("Yes" in Step S14), the variable number k is incremented to k = k + 1 (Step S15)
and a part of the process steps from Step S12 is repeated.
20 [0049] On the other hand, if the header open response delay time calculation
unit 131 determines in Step S14 that the correlation coefficient Corr (k) obtained
this time is not larger than the correlation coefficient Corr (k-1) ?No" in Step S14),
the header open response delay time calculation unit 131 determines the variable
number k to be a header open response delay length (L-delay-open-cur), that is,
25 L-delay-open-cur = k (Step S16).
[0050] Next, the header open response delay time calculation unit 131
calculates a current header open response delay time (t-delay-open-cur)
according to the following equation (2) making use of Vs-ave that is an average
strip running speed (Step S17).
30
t - delay - open - cur = k l Vs - ave (2)
where VS - ave = Vs(rn) l k
[0051] Next, the header open response delay time calculation unit 131
calculates a header open response delay time (t-delay-open) equal to a weighted
5 average between the current header open response delay time (t-delay-open-cur)
axid the previous header open respoinse delay time (t-delay-open-pre) which is
calculated for a strip rolled in the previously performed rolling process according
to the following equation (3) (Step S18).
Where a is often called a learning coefficient and 0 < a <1.
[0052] Finally, the header open response delay time calculation unit 131
stores the header open response delay time (t-delay-open) in the header open
15 response delay storage section 132 (Step S19) and the process in Fig.12 ends. The
header open response delay time (t-delay-open) stored in the header open
response delay storage section 132 is to be used as a previous measured header
open response delay time (t-delay-open-pre) for a new strip 151 being rolled next
time.
20 [0053] In the above explained process flow, a variable number k at which the
correlation coefficient Corr (k) starts to decrease after increasing when the
correlation coefficient is calculated for each of plural k increasing is taken as
L-delay-open-cur. On the other hand, the correlation coefficient Corr (k) is
calculated for each of the plural k = 1, 2, ---,2 L1) and a variable number k which
25 is among the plural ks and corresponds to the maximum correlation coefficient
may be taken as L-delay-open-cur..
LO0541 In the above explained process flow, although the header open
response delay time (t-delay-open) is calculated as a weighted average between
the current header open response delay time (t-delay-open-cur) and the previous
30 measured header open 'esponse delay time (t-delay-open-pre) in Step S18, Step
,518 may be skipped. The current header open response delay time
19
(t-delay-open-cur) is taken as the header open response delay time
(t-delaypopen) without any modification.
[0055] The process flow as explained in Fig.12 can apply to the case in which
the header open response delay time is relatively short (Case 2, See Fig.ll) if part
5 of the process steps is modified. As is explained, Case 2 in Fig.11 may be
considered as corresponding to Case 1 in which the target length direction coiling
temperatures are exchanged for the previous measured length direction coiling
temperatures 141a. Accordingly, the header open delay time is obtained in Case
2 by exchanging the target length direction coiling temperatures for the previous
10 measured length direction coiling temperatures 141a and substituting the length
11 into the length LI in the process flow in Fig. 12.
[0056] Moreover, the process performed by the header close response delay
time calculation unit 133 is more or less the same as the process flow as indicated
in Fig.12.
15 A header close response delay time (t-delay-close) is a response delay
time for water to stop being discharged from the cooling headers 157 when an
instruction of "Close" is given to the cooling headers 157. Since the target length
direction coiling temperature becomes gradually higher in the U-pattern region
for the tail end portion of the strip 151 from the target length direction coiling
20 temperature (TO) in an intermediate portion of the U-pattern, more and more
instructions to change from "Open" to "Close" are gradually output to the cooling
headers 157. Therefore, it is possible to calculating a header close response delay
time based the relation between the target length coiling temperatures and the
previous measured length direction coiling temperatures 141a in a region
25 inclusive of the U-pattern region for the tail end portion of the strip 151.
[0057] In this calculation, it should be understood that it is possible for the
header close response delay time calculation unit 133 to calculate the header close
response delay time following the same process as what is described in Fig.12,
assuming the front end portion of the strip 151 is exchanged for the tail end
30 portion of the strip 151 and that the time axis is reversed. Then, the header close
response delay time (t-delay-close) that is calculated in the above mentioned way
by the header close response delay time calculation unit 133 is to be stored in the
header close response delay storage section 134.
2 0
[0058] Fig.13 shows an example of a flowchart of process steps performed by
the header openlclose pattern output unit 135. When a strip 151 starts being
cooled, the cooling headers 157 are ordinarily in the close state. Then, the header
openlclose pattern output unit 135 firstly sets the header open response delay
5 time (t-delay-open) to an initial value of the header response delay time (t-delay),
that is, t-delay = t-delay-open (Step S21).
[0059] Next, the header openlclose pattern output unit 135 receives a current
strip running speed of the strip 151 that is being rolled and a measured rolled out
length of the strip 151 from the rolling mill 152. Both the current strip running
10 speed and the measured rolled out length are collected by the rolling data
collection unit 136 and stored in the measured rolling data storage section 137.
The measured rolled out length is a length of the strip 151 from the front end to
the delivery side position of the rolling mill 152.
[0060] A distance from the delivery side position of the rolling mill 152 to each
15 cooling header 157 is an equipment constant. Therefore, the header openlclose
pattern output unit 135 is able to obtain a section number of a control section of
the strip 151 that is running just under the cooling header 157 at a time when the
header openlclose pattern is output, making use of the distance from the delivery
side position of the rolling mill 152 to each of the cooling headers 157 that is
20 known and the rolled out length of the strip 151 obtained by the rolling data
collection unit 136. In addition the header openlclose pattern output unit 135 is
able to obtain a section number of a control section of the strip 151 that is to
arrive just under the cooling header 157 the header response delay time (t-delay)
after the time when the header openlclose pattern is output.
25 [0061] As a result, the header openlclose pattern output unit 135 obtains a
header openlclose pattern associated with a control section of the strip 151
arriving just under the cooling header 157 the header open response delay time
(t-delay) after the time when the header openlclose pattern is output (Step S23).
[0062] Next, the header openlclose pattern output unit 135 determines
30 whether the obtained header openlclose pattern corresponds to "Open" or "Close"
(Step S24). If the header openlclose pattern is "Open" (Open in Step S24), the
heade~o. penlclose pattern output, unit set,s the header open response delay time
21
(t-delay-open) to a header response delay time of a cooling header 157 to which
the instruction of "Open" is output, that is, t-delay = t-delay-open (Step S25).
[0063] On the other hand, if the obtained header openlclose pattern is "Close"
(Close in Step S24), the header openlclose pattern output unit sets the header
5 close response delay time (t-delay-close) to a header response delay time of a
cooling header 157 to which the instruction of "Close" is output, that is, t-delay =
t-delay-close (Step S26).
100641 Next, the header openlclose pattern output unit 135 outputs the header
openlclose pattern for the control section of the strip 151 that is to arrive just
10 under the cooling header 157 the header response delay time (t-delay) after the
time when the header openlclose pattern is output (Step S27).
[0065] Then if the strip 151 is not completely coiled (No in Step S28), the
header openlclose pattern output unit 135 repeatedly performs the process of the
steps from S22 to S28 and when the strip 151 is completely coiled (Yes in Step
15 S28), the header openlclose pattern output unit 135 stops its operation as
described in Fig. 13.
Coo661 As explained above, an important point of what the header openlclose
pattern output unit 135 performs is that it is not at a timing when a control
section of the strip 151 associated with the header openlclose pattern arrives just
20 under the cooling header 157 but a header open response delay time before the
control section of the strip 151 arrives just under the cooling header 157 that the
header openlclose pattern output unit 135 outputs a header openlclose pattern.
There is a time difference in the timing at which the header openlclose pattern is
output to cooling headers 157 between the cooling headers 157 which are
25 instructed to open and the other cooling headers which are instructed to close.
[0067] As has been explained, every time a strip 151 is rolled, the shift length
of the strip 151, at which the correlation between the target length direction
coiling temperature (Ttgt(i)) and the previous measured length direction coiling
temperature (Tmea(j)) is maximum, is calculated and converted to a shift time
30 and a header response delay time (t-delay) is obtained according to the shift time,
as indicated in Fig.12. In short, the header response delay time (t-delay) is
det,ermined based on how t,he strip 151 is actually cooled by t,he cooling machine
153 in this embodiment. This embodiment should be able to take into
22
consideration and deal with the change in the header response delay time
(t-delay) that is caused by such changes as those in a water level or a water
amount of the cooling water tank. Therefore the rolled strip coiling temperature
control apparatus 100 according to this embodiment enables very accurate control
5 over the coiling temperature even if the header response delay time (t-delay)
changes.
Lo0681
There is another coiling temperature control method to have both the
front end portion and the tail end portion of a rolled strip such as the strip 151
10 uncooled. Fig.14 shows an example of target length direction temperatures when
non-cooling regions are set in a front end and a tail end portions of a rolled strip
instead of U-pattern regions. In this example, the target length direction coiling
temperature determination unit 111 determines the target length direction
coiling temperature based on whether there is a no-cooling region set in advance
15 in accordance with classification on the strip type or thickness or not and nocooling
region lengths L3 and L4 and stores the determined target length
direction coiling temperature in the target length direction coiling temperature
storage section 116.
[0069] Even when the no-cooling control is carried out, the header open
20 response delay time calculation unit 131 and the header close response delay time
calculation unit 133 compare the target length direction coiling temperatures
with the previous measured length direction coiling temperatures, obtain a shift
length at which the correlation between them is maximum, convert the shift
length to a shift time and obtain the header response delay time, in the same way
25 as the above explained embodiment. Therefore Modification 1 of the present
embodiment has the same effect as the above mentioned embodiment.
[0070]
Fig. 15 shows an example of target length direction temperatures when
non-cooling regions are set in parts of front end and tail end portions of a rolled
30 strip 151 while U-pattern regions are set in the rest of the front end and tail end
portions of the rolled strip. In this example, the target length direction coiling
temperature determination unit 111 determines the target length direction
coiling temperature based on whether there is a no-cooling region set in advance
23
in accordance with classification on the strip type or thickness or not, no-cooling
region lengths L3 and L4 and the U-pattern data and stores the determined
target length direction coiling temperature in the target length direction coiling
temperature storage section 116.
5 [00711 In the example of Fig.15, a L3 long portion of the strip 151 from its
front end and a L4 long portion of the strip 151 from its tail end are set to nocooling
regions. In addition, a L1 long portion of the strip 151 from its front end
except the non-cooling region and a L2 long portion of the strip 151 from its tail
end except the non-cooling region are set to U-pattern regions.
10 [0072] When there are both the no-cooling regions and the U-pattern regions,
the header open response delay time calculation unit 131 and the header close
response delay time calculation unit 133 compare the target length direction
coiling temperatures with the previous measured length direction coiling
temperatures, obtain a shift length at which the correlation between them is
15 maximum, convert the shift length to a shift time and obtain the header response
delay time, in the same way as the above explained embodiment. Therefore
Modification 2 of the present embodiment has the same effect as the above
mentioned embodiment.
LO0731
20 In the embodiment above mentioned, the header open response delay
time calculation unit 131 and the header close response delay time calculation
unit 133 obtain header response delays represented in time and store the header
open response delay time and the header close response delay time respectively in
the header open delay storage section 132 and the header close delay storage
25 section 134. On the hand, Modification 3 of the present embodiment has header
response delays represented in the shift length of the strip 151 running and store
a header open response delay and a header close response delay both represented
in the shift length respectively in the header open response delay storage section
132 and the header close response delay storage section 134.
30 [0074] If data is used in the process steps as above mentioned, there is no
significant influence on the result because there is a one to one relation between
the shift length and the h ~ a drees~po nse delay time through the strip running
24
speed. Therefore, Modification 3 of the present embodiment has the same effect
as the embodiment above mentioned.
[0075]
When the header openlclose pattern preset unit 112 determines a
5 header openlclose pattern for the cooling headers 157 with respect to the length
direction of the strip 151, different cooling patterns for an identical target length
direction coiling temperature, such as rapid cooling by having cooling headers 157
of the bank 156 on the side of the rolling mill 152 opened or slow cooling by
having cooling headers 157 of the bank 156 on the side of the down-coiler 159
10 opened, are performed depending on the classification of the strip type and
thickness. If there is a variation in the header response delay between the cooling
headers 157 in a bank 156, this variation leads to accuracy of the coiling
temperature control lowering.
[0076] In Modification 4 of the present embodiment, the header open response
15 delay storage section 132 and the header close response delay storage section 134
store the header open response delay times and the header close response delay
times which are classified according to the strip type, the strip thickness, the strip
width, the cooling pattern and so on.
[0077] Fig.16 shows an example of data of header open response delay times
20 which are classified and stored in a header open response delay storage section
132. In Fig.16, the header open response delay times are classified in detail
according to the strip type, the strip thickness, the strip width and the cooling
pattern. The header close response delay times to be stored in the header close
response delay storage section 134 may be classified in the same way, though they
25 are not indicated in a figure.
[0078] As mentioned, the classified header response delays (header open
response delay time and header close response delay time) are stored, which
enables more accurate coiling temperature control.
[0079] The present invention should not be limited to the embodiments above
30 explained and includes various other embodiments and modifications. For
example, the above mentioned embodiments are explained in detail so that the
present invent.ion is easily lmderst,ood. Furt,herrnore, it. should be understood
that a part of the configuration of an embodiment of the present invention may be
25
replaced with a part of the configuration of other embodiment of the present
invention and that it is possible to add a part or a whole of the configuration of an
embodiment of the present invention to the configuration of other embodiment of
the present invention.
5
26

We Claim:
1. A rolled strip coiling temperature control apparatus comprising:
a header openlclose pattern output unit configured to output a header
openlclose pattern of data for instructing a plurality of cooling headers to open or
5 close, the plurality of cooling headers installed along a length direction of a rolled
strip and between a rolling mill and a rolled strip coiling machine for coiling the
rolled strip that is rolled by the rolling mill,
an openlclose pattern preset unit configured to set the openlclose
pattern for each of control sections of the rolled strip into which the rolled strip is
10 partitioned in the length direction of the rolled strip, each of the control sections
having a predetermined length in the length direction of the rolled strip,
a coiling temperature collection unit for collecting temperatures on the
rolled strip being coiled by the rolled strip coiling machine, and
a header response delay calculation unit configured to calculate a shift
15 length in the length direction of the rolled strip, the shift length by which
previous measured length direction coiling temperatures collected by the coiling
temperature collection unit of the rolled strip previously rolled shift from target
length direction coiling temperatures that are set in advance for the rolled strip
and calculate a header response delay time based on the shift length and a rolled
20 strip, running speed,
wherein the header openlclose pattern output unit outputs the header
openlclose pattern to the plurality of cooling headers at a time the calculated
header response delay time before the control section of the rolled strip that is
associated with the header openlclose pattern to be output arrives at a position
25 where the cooling header to which the header openlclose pattern is output is
installed.
2. The rolled strip coiling temperature control apparatus as described in
claim 1, wherein the header response delay calculation unit is configured to
30 calculate a correlation coefficient between the measured length direction coiling
temperatures and the target length direction coiling temperatures both on either
a front, end portion or a tail end portion of t.he rolled strip every time either the
measured length direction coiling temperatures or the target length direction
27
coiling temperatures are shifted forward or rearward, obtain a shift length at
which the correlation coefficient is maximum, the shift length by which the
measured length direction coiling temperatures shift from the target length
direction coiling temperatures, and calculate the header response delay time.
5
3. The rolled strip coiling temperature control apparatus as described in
claim 1, wherein the header response delay calculation unit obtains a header open
response delay time for the header response delay time used when an instruction
is output to the cooling header to open based on the measured length direction
10 coiling temperatures and the target length direction coiling temperatures on a
front end portion of the rolled strip, and obtains the header close response delay
time for the header response delay time used when an instruction is output to the
cooling header to close based on the measured length direction coiling
temperatures and the target length direction coiling temperatures on a tail end
15 portion of the rolled strip.
4. The rolled strip coiling temperature control apparatus as described in
claim 3, wherein the header openlclose pattern output unit outputs the header
openlclose pattern to the cooling headers to open at a first timing and to the other
20 cooling headers to close at a second timing is independent of the first timing.
5. A method for controlling a coiling temperature of a rolled strip to be
cooled with cooling water discharged out of a plurality of cooling headers installed
along a length direction of a rolled strip and between a rolling mill and a rolled
25 strip coiling machine to coil the rolled strip that is rolled by the rolling mill, the
method comprising steps by a control device to control the plurality of cooling
headers,
an openlclose pattern preset step of setting a header openlclose pattern
of data for instructing the plurality of cooling headers to open or close for each of
30 control sections of the rolled strip into which the rolled strip is partitioned in the
length direction of the rolled strip, each of the control sections having a
predetermined length in the lengt,h direct,ion of the rolled strip,
28
a coiling temperature collection step of collecting temperatures on the
rolled strip being coiled by the rolled strip coiling machine,
a header response delay calculation step of calculating a shift length in
the length direction of the rolled strip, the shift length by which previous
5 measured length direction coiling temperatures that are collected by the coiling
temperature collection step of the rolled strip previously rolled shift from target
length direction coiling temperatures that is set in advance for the rolled strip,
and calculating a header response delay time based on the shift length and a
rolled strip running speed, and
10 a header openlclose pattern output step of outputting the header
openlclose pattern to the plurality of cooling headers at a time the calculated
header response delay time before the control section of the rolled strip that is
associated with the header openlclose pattern to be output arrives at a position
where the cooling header to which the header openlclose pattern is output is
15 installed.
6. The method for controlling a coiling temperature of a rolled strip as
described in claim 5, wherein the control device calculates a correlation coefficient
between the measured length direction coiling temperatures and the target length
20 direction coiling temperatures both on either a front end portion or a tail end
portion of the rolled strip every time either the measured length direction coiling
temperatures or the target length direction coiling temperatures are shifted
forward or rearward, obtain a shift length at which the correlation coefficient is
maximum and calculate, the shift length by which the measured length direction
25 coiling temperatures shift from the target length direction coiling temperatures,
and calculate the header response delay time in the header response delay
calculation step.
7. The method for controlling a coiling temperature of a rolled strip as
30 described in claim 5, wherein the control device obtains a header open response
delay time for the header response delay time used when an instruction is output
to the cooling header to open based on the measured length direction coiling
temperatures and the target length direction coiling temperatures on a front end
29
portion of the rolled strip, and obtains a header close response delay time for the
header response delay time used when an instruction is output to the cooling
header to close based on the measured length direction coiling temperatures and
the target length direction coiling temperatures on a tail end portion of the rolled
5 strip.
8. The method for controlling a coiling temperature of a rolled strip as
described in claim 7, wherein the control device outputs the header openlclose
pattern to the cooling headers to open at a first timing and to the other cooling
10 headers to close at a second timing is independent of the first timing.