JP2760275B2 - Cooling control device for metal strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling control device for a strip-shaped metal material such as a hot strip after hot rolling.

[0002]

2. Description of the Related Art In order to obtain a wide range of materials having various properties in hot rolling, it is necessary to be able to change a cooling pattern in a cooling step after hot rolling. As apparatuses for this purpose, conventionally, Japanese Patent Application Laid-Open Nos. 58-221606 and 62-5
There is a technique disclosed in 7709 and the like. FIG.
1 is a schematic diagram showing the configuration of a conventional cooling control device disclosed in Japanese Patent Application Laid-Open No. 22221/1996, wherein 1 is a cooling bank, 4 is a final stage stand of a hot finishing mill, 5 is a winder, and S is a strip. Is shown.

The strip S exits the final stand 4 of the hot finishing mill, passes through the cooling bank 1 in the direction of the arrow, is cooled to a predetermined temperature, and is wound up by the winder 5. . During this time, the strip speed of the strip S is detected by the speedometer 6 attached to the final stage stand 4, and the finishing outlet temperature is measured by the finishing outlet thermometer 7 before leaving the final stage stand 4 and entering the cooling bank 1. The thickness is measured with a thickness gauge 8,
Further, the winding temperature is sampled and measured by the winding thermometer 10 at a predetermined timing or at regular intervals at a position immediately before being taken out of the cooling bank 1 and wound up by the winding machine 5.

The cooling control unit 31 calculates the position and temperature of each sampling point from the detected strip speed, finishing outlet temperature, thickness, and the actual value of the cooling pattern of the cooling bank 1, and each sampling point is used as a winding thermometer. The temperature at the time of reaching 10 is predicted, and the cooling pattern is set in advance for the nozzles in the cooling bank 1 located downstream from the sampling point so that the deviation between the predicted value and the predetermined target winding temperature is reduced. Change control is performed according to the specified priority water injection order.

FIG. 7 is a schematic diagram showing the configuration of another conventional cooling control technique disclosed in Japanese Patent Publication No. 5-25567. In this prior art, the cooling bank 1 is divided into a plurality of cooling banks 1a to 1n along the moving direction of the strip S, and the outlet of the final stage stand 4 of the hot finishing mill has a finishing outlet temperature. In addition, a plurality of intermediate thermometers 9a and 9b are arranged at predetermined positions between the divided cooling banks 1a to 1n, and further above and below the moving area of the strip S immediately before the winding machine 5, and the winding is performed. In this configuration, thermometers 10a and 10b are provided.

The cooling control unit 41 includes a temperature distribution estimating means 42, an average temperature estimating means 43, and a cooling amount adjusting means 44. The actual surface temperatures detected by the intermediate thermometers 9a and 9b and the characteristic values relating to the heat conduction of the strip are provided. From the temperature distribution in the thickness direction
The average temperature of the strip S is estimated based on the estimated temperature distribution and the actual surface temperature, and the amount of cooling water in each of the cooling banks 1a to 1n is adjusted so that the average temperature matches the target winding temperature.

[0007]

Since the former cooling control method is feed-forward control based on the model estimated winding temperature by the finishing outlet thermometer 7, for example, the response speed of the actuator, the water level on the strip S, etc. When a disturbance that is difficult to accurately predict occurs, there is a problem that winding temperature control accuracy is poor. Further, the latter cooling control method has a problem that the process from the detection of the surface temperature of the strip to the determination of the cooling water amount is complicated, the load on the computer is high, and the control result is not evaluated as needed.

The present invention has been made in view of such circumstances, and it is an object of the present invention to compensate for the conventional control without increasing the computer load, and to finally enable the winding temperature to be accurately controlled to the target temperature. It is an object of the present invention to provide a belt-shaped metal material cooling control device.

[0009]

According to a first aspect of the present invention, there is provided a cooling control apparatus for a strip-shaped metal material along a moving area of the strip-shaped metal material until the strip-shaped metal material after hot rolling is wound on a winding machine. In the cooling apparatus for a strip-shaped metal material, the cooling control of which is performed by a plurality of cooling machines disposed in the cooling apparatus, the cooling apparatus is provided on the inlet side, the middle side, and the outlet side of the cooling machine, and the inlet side of each sampling point of the strip-shaped metal material. temperature,
The inlet side thermometer, intermediate thermometer and winding thermometer for measuring the intermediate temperature and winding temperature, and each sampling point of the strip metal material are tracked, and the position of the sampling point and the temperature at that position are measured for the strip metal material. Means for predicting and calculating based on the speed and the cooling performance of the cooler to obtain a target intermediate temperature for the strip-shaped metal material at the intermediate thermometer installation position, and corresponding to a deviation between the set target winding temperature and the measured winding temperature. Means for changing the target intermediate temperature, and means for performing cooling control for a cooler downstream from the target intermediate temperature set by the means in accordance with the deviation between the target intermediate temperature and the actually measured intermediate temperature. It is characterized by doing.

According to a second aspect of the present invention, there is provided a cooling control apparatus for a strip-shaped metal, which is disposed along a moving range of the strip-shaped metal material before the hot-rolled strip-shaped metal material is wound around a winding machine. In the apparatus for controlling the cooling of a strip-shaped metal material, the intermediate thermometer and the measured winding temperature, which are arranged at intervals on the outlet side of the cooler and sample and measure the measured intermediate temperature of the strip-shaped metal material, are provided. Winding thermometer to be obtained, means for obtaining a recuperation temperature difference which is a difference between the measured intermediate temperature and the measured winding temperature at each sampling point, and a sum of the reheat temperature difference and a predetermined target winding temperature. Means for determining a target intermediate temperature at an intermediate thermometer installation position, and means for controlling the cooler such that a difference between the target intermediate temperature and the measured intermediate temperature of the intermediate thermometer is reduced. I do.

[0011]

According to the first aspect of the present invention, the winding temperature is made uniform by reflecting the control result as needed in the control for eliminating the deviation between the measured intermediate temperature and the target intermediate temperature of the strip-shaped metal material between the coolers. In addition, the cooling control can be performed with high accuracy. According to the second aspect of the present invention, it is possible to accurately detect a temperature difference generated at the time of winding the strip-shaped metal material due to reheating, to reduce a deviation from a target winding temperature, and to further improve control accuracy. I can do it.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments. (Embodiment 1) FIG. 1 is a block diagram showing a configuration of Embodiment 1, wherein 1a and 1b are cooling banks, 4 is a final stage stand of a hot finishing mill, 5 is a winding machine, and S is a strip. Is shown. The strip S passes through the final bank stand 4 of the hot finishing mill, passes through the cooling banks 1a and 1b in the direction of the arrow, is cooled to a predetermined temperature, and is wound by the winder 5.

During this time, the strip S has a strip speed measured by a speedometer 6 attached to the final stage stand 4, a finishing outlet thermometer 7 between the final stage stand 4 and the cooling bank 1 a, and a finishing outlet temperature measured by a thickness gauge 8. , The thickness is detected, and the intermediate temperature is measured by the intermediate thermometer 9 immediately after leaving the cooling bank 1a.
Further, the winding temperature is sampled and measured by a winding thermometer 10 immediately before the winding machine 5. Each of the cooling banks 1a and 1b is configured by arranging a number of nozzles, respectively, facing above and below the pass area of the strip S, and the water injection amount is controlled by a cooling pattern predetermined by the water injection control device 15. It is to be adjusted.

Reference numeral 11 denotes a cooling control unit. The cooling control unit 11 calculates and outputs a target temperature for the material front end of the target temperature correcting device 13 based on the set data from the setter 12. The speedometer 6, the finish outlet thermometer 7, the thickness gauge 8, the winding thermometer
Each detected value of 10 and the opening / closing results of the cooling bank 1a are taken and stored in the memory. An opening / closing command for the cooling bank 1a is calculated based on each of these data and output.

Then, the position of each sampling point is calculated according to the following equation (1) based on the strip speed and the strip temperature at each sampling point based on the past opening / closing actual values taken from the cooling bank 1a.

[0016]

(Equation 1)

The heat transfer coefficient hω in the equation (1) is the sum of the heat transfer coefficient h _A during air cooling and the heat transfer coefficient h _w during water cooling, and is expressed by the following equation (2).

[0018]

(Equation 2)

That is, until the leading end of the strip S reaches the finishing outlet thermometer 7, the strip including the thickness indication value, the strip speed indication value, and the preset target winding temperature of the strip S input from the setting device 12. Based on the temperature instruction value of each part of S, the calculation according to the equation (1) is performed and output to the target temperature correction device 13. On the other hand, after the leading end of the strip S reaches the finishing outlet thermometer 7, the speedometer 6, the finishing outlet thermometer 7, the thickness gauge 8, the intermediate thermometer 9, and the winding thermometer 10 are used to detect the same. Perform the operation according to equation (1),
An open / close command is output to the cooling bank 1a.

The target temperature correcting device 13 calculates the target intermediate temperature and the target winding temperature at the installation positions of the intermediate thermometer 9 and the winding thermometer 10 from the cooling control unit 11 and the measured winding temperature from the winding thermometer 10. Take-in, compare the set target winding temperature with the measured winding temperature, determine whether the deviation is beyond the allowable range, and if not, the target intermediate temperature input from the cooling control unit 11 The difference is output to the subtractor 14, and if the deviation exceeds the allowable range, the temperature is changed to another predetermined target intermediate temperature and output to the subtractor 14.

For example, when the deviation is negative outside the allowable range, the target intermediate temperature is changed to a lower target intermediate temperature. When the deviation is positive outside the allowable range, the target intermediate temperature is changed to a higher target intermediate temperature.
Output to The subtractor 14 calculates a deviation between the target intermediate temperature input from the target temperature correction device 13 and the actual measured intermediate temperature measured by the intermediate thermometer 9 and outputs the deviation to the water injection control device 15.

The water injection control device 15 stores a table of a deviation between the intermediate temperature measured by the intermediate thermometer 9 and the target intermediate temperature inputted from the target temperature correcting device 13, and a cooling pattern in the cooling bank 1b corresponding to each deviation. The cooling pattern is selected according to the deviation input from the subtractor 14, and the cooling bank 1b is controlled based on the selected cooling pattern.

FIG. 2 shows the results of a comparison test between the apparatus of the present invention and the conventional apparatus. FIG. 2A shows the cooling banks 1a, 1 of the first embodiment.
FIG. 2 (b) shows the temporal transition between the target intermediate temperature and the measured intermediate temperature at the installation position of the intermediate thermometer 9 arranged in the middle of b. It is a graph each showing the relationship with the measured winding temperature. As the hot strip, medium carbon steel having a thickness of 9.01 mm and a width of 869 mm was used. 2 (c) and 2 (d) show the results when the conventional apparatus is applied to strips having the same dimensions as those for comparison.

In the apparatus of the present invention, as shown in FIG. 2B, the measured winding temperature is slightly lower than the set target winding temperature, so that the target intermediate temperature is set to T as shown in FIG. By changing from ₀ (initial value) to T ₁ (T ₁ > T ₀ ), which is higher than this, the measured winding temperature becomes substantially equal to the set target winding temperature, and thereafter, as shown in FIG. by the target intermediate temperature as shown in FIG. 2 (a) since the actual winding temperature becomes slightly higher than the set target coiling temperature was changed from T ₁ to T ₀ as shown, measured winding temperature set It can be seen that a state substantially matching the target winding temperature is obtained.

On the other hand, in the conventional apparatus, since the control for the intermediate temperature is insufficient, the deviation between the measured winding temperature and the set target winding temperature is remarkably large as shown in FIG. It is clear that was not obtained. By the way, the target accuracy for the target winding temperature within the range of ± 25 ° C is
The average was 77% when the conventional method was used, but it was confirmed that the average was improved to 96% in the apparatus of the present invention.

In the first embodiment, the cooling bank
The target intermediate temperature between 1a and 1b is changed according to the deviation between the set target winding temperature and the measured winding temperature.
1b is the difference between the target intermediate temperature and the actual measured intermediate temperature.
Since the cooling control is performed in accordance with the cooling pattern determined using the cooling pattern conversion table, the cooling control can be performed so that the temperature of the strip S is uniform over the entire length, and the accuracy of the winding temperature control can be significantly improved. Become.

(Embodiment 2) FIG. 3 is a schematic diagram showing the configuration of Embodiment 2 of the present invention. In Embodiment 2, the cooling bank is divided into three parts, and the cooling banks 1a and 1b are connected to each other. while,
Intermediate thermometers 9a and 9b are provided between the cooling banks 1b and 1c, respectively, and the target temperature correcting devices 13a and 13b are provided for the cooling banks 1b and 1c, respectively.
, Subtractors 14a, 14b and water injection control devices 15a, 15b. Other configurations are substantially the same as those of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

In the second embodiment, the cooling control unit 11 includes an intermediate thermometer 9a, 9b and a winding thermometer 10 corresponding to the leading end of the material.
The target intermediate temperatures T _0a , T _0b , and the target winding temperature T _CM at the respective installation positions are calculated, and the target intermediate temperatures T _0a , T _0b and the target temperature correctors 13
For b, a target intermediate temperature T _0b and a target winding temperature T _CM are output. The target temperature corrector 13a calculates a deviation between the measured intermediate temperature of the intermediate thermometer 9b and the target intermediate temperature T _0b for each sampling point at the position where the intermediate thermometer 9b is installed. If the deviation is within the allowable range, the target temperature is corrected. Subtractor 14a subtracts intermediate temperature T _0a
If they exceed the permissible range, another target intermediate temperature corresponding to each is output to the subtractor 14a.

The target temperature correcting device 13b is provided with the winding thermometer 10
And the measured winding temperature, a deviation between the set target coiling temperature T _CM, the target intermediate temperature T _0b is output to the subtractor 14b Within the deviation is allowable range and when it exceeds the permissible range , And outputs another target intermediate temperature corresponding to each to the subtractor 14b. The control contents of the subtractors 14a and 14b and the water injection control devices 15a and 15b are respectively the same as those of the subtractor 14 and the water injection control device shown in the first embodiment.
It is substantially the same as that of No. 15, and the description is omitted.

In the second embodiment, the control is performed such that the measured intermediate temperatures coincide with the respective target intermediate temperatures at a plurality of intermediate positions from the final stage stand 4 to the winder 5, and the cooling control is performed. Accuracy can be further improved.

(Third Embodiment) In the third embodiment, an error in the winding temperature due to reheating occurring after the cooling of the strip S is completed and before the strip S is wound by the winding machine 5 can be eliminated. is there. FIG. 4 is a schematic diagram showing still another embodiment of the present invention. In the figure, 1 indicates a main cooling bank, 2 indicates a fine adjustment cooling bank, and 21 indicates a cooling control unit. The intermediate thermometer 9 is installed so as to face the moving area of the strip S immediately after the outlet of the cooling bank 2 for fine adjustment. Other configurations are substantially the same as those of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

The cooling control section 21 includes a recuperation temperature difference calculating section 22, a target intermediate temperature calculating section 23, an intermediate temperature error calculating section 24, and a water injection amount calculating section 25. The recuperation temperature difference calculation unit 22 takes in the measured intermediate temperature from the intermediate thermometer 9 and the measured winding temperature from the winding thermometer 10 at regular intervals or every time the strip S moves a predetermined length, and calculates the deviation. That is, the reheat temperature difference is calculated, stored in the memory, and output to the target intermediate temperature calculation unit 23.

The target intermediate temperature calculator 23 calculates the sum of the target winding temperature and the recuperation temperature difference that have been set and input, and outputs the sum to the intermediate temperature error calculator 24 as the target intermediate temperature. The intermediate temperature error calculating unit 24 calculates a deviation between the input target intermediate temperature and the measured intermediate temperature obtained by the intermediate thermometer 9, calculates a water injection amount based on the deviation and the control gain, and calculates the water injection amount. Output to the arithmetic unit 25. The water injection amount calculation unit 25 calculates a correction amount of the water injection amount for the main cooling bank 1 based on a proportional / integral operation, and outputs a control signal to the main cooling bank 1 to realize this.

Next, a control procedure according to the third embodiment will be described. First, from the time when the leading end of the strip S reaches the winding thermometer 10, at every fixed time or every time the strip S moves a fixed distance, the finishing outlet thermometer 7, the thickness gauge 8, the intermediate thermometer 9
And the detected values of the winding thermometer 10 are stored in the memory together with the sampling position and strip speed at that moment.

The leading end of the strip S is a winding thermometer 10
Is reached on the strip S recorded at the i-th time from the point when the temperature has reached, that is, the i-th sampling point.
Numeral 22 calculates and records the difference (recovery temperature difference) _ΔToi between the measured temperatures of the intermediate thermometer 9 and the winding thermometer 10 according to the following equation (3), and outputs this to the intermediate temperature calculator 23. I do.

[0036]

(Equation 3)

The target intermediate temperature calculator 23 calculates the target intermediate temperature T _{MMj at the j-} th (= i + 1) -th sampling point according to the following equation (4), and outputs this to the intermediate temperature error calculator 24. .

[0038]

(Equation 4)

The intermediate temperature error calculator 24 calculates a deviation E _j between the target intermediate temperature T _{MMj at} the j-th sampling point and the measured intermediate temperature T _Mj according to the following equation (5), and calculates the water injection amount calculator 25.
Output to

[0040]

(Equation 5)

The modifications injection amount for the main cooling bank 1 required injection amount calculating unit 25 to eliminate the deviation E _j min △ Q _j
Is calculated according to the following equation (6) as a weighted sum of the signed sum of the intermediate temperatures from the first sampling point to the j-1 sampling point (minute installation) and the intermediate temperature error at that moment. In accordance with this, a control signal is output to main cooling bank 1.

[0042]

(Equation 6)

FIG. 5 is a graph showing the results of a comparison test between the apparatus of the present invention and the conventional apparatus, wherein the horizontal axis represents time, and the vertical axis represents the measured winding temperature. As the strip, a low-carbon steel having a thickness of 1.6 mm and a width of 1220 mm was used. FIG.
(a) shows the results of the apparatus of the present invention, and FIG. 5 (b) shows the results of the conventional apparatus. As is clear from this, the deviation of the measured winding temperature from the target winding temperature in the device of the present invention can be greatly reduced as compared with the conventional device.

In the third embodiment, the recuperation temperature difference or the recuperation amount count is obtained by calculating the recuperation temperature difference and the target intermediate temperature from the measured winding temperature and the measured intermediate temperature at each sampling point. Compared with the conventional method that is obtained in advance, the accuracy of estimating the recuperation is improved, and the control accuracy of the winding temperature can be further improved. In addition, as the sampling point moves with the movement of the strip S, the first recuperation temperature difference is repeatedly measured, so that even when the recuperation temperature difference greatly changes over the entire length of the strip, the accurate winding temperature is obtained. Control becomes possible.

[0045]

As described above, in the apparatus of the present invention, it is possible to accurately control the temperature at the target winding temperature over the entire length of the strip-shaped metal material, and to stabilize a product which can satisfy recent advanced material requirements. The present invention has an excellent effect, for example, it can be manufactured by using the method described above.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a graph showing a comparison test result between an example of the present invention and a conventional device.

FIG. 3 is a schematic diagram showing a configuration of another embodiment 2 of the present invention.

FIG. 4 is a schematic diagram showing a configuration of still another embodiment 3 of the present invention.

FIG. 5 is a graph showing a comparison test result between Example 3 shown in FIG. 4 and a conventional device.

FIG. 6 is a schematic view of a conventional device.

FIG. 7 is a schematic view of another conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main cooling bank 1a, 1b Cooling bank 2 Fine adjustment bank 4 Final stage stand 5 Winding machine 6 Speedometer 7 Finishing outlet thermometer 8 Thickness gauge 9, 9a, 9b Intermediate thermometer 10 Winding thermometer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-23009 (JP, A) JP-A-2-75410 (JP, A) JP-A-62-57709 (JP, A) JP-A-58-58 221606 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B21B 37/76 B21B 45/02

Claims (2)

(57) [Claims] 1. A strip-shaped metal material which is subjected to cooling control by a plurality of cooling machines arranged along a moving region of the strip-shaped metal material before winding the strip-shaped metal material by a winder. In the cooling control device, an inlet-side thermometer, which is disposed on each of the inlet side, the middle side, and the outlet side of the cooler and measures the inlet side temperature, the intermediate temperature, and the winding temperature at each sampling point of the strip-shaped metal material, With a thermometer and a winding thermometer, each sampling point of the strip-shaped metal material is tracked, and the position of the sampling point and the temperature at that position are predicted and calculated based on the speed of the strip-shaped metal material and the cooling performance of the cooler, and Means for obtaining a target intermediate temperature for the strip-shaped metal material at the intermediate thermometer installation position, and means for changing the target intermediate temperature in accordance with the deviation between the set target winding temperature and the measured winding temperature,
Means for controlling cooling of a cooler downstream thereof in accordance with a deviation between the target intermediate temperature set by the means and the actually measured intermediate temperature. apparatus. 2. The cooling of a strip-shaped metal material which is cooled and controlled by a cooler arranged along a moving area of the strip-shaped metal material until the strip-shaped metal material after hot rolling is wound on a winder. In the control device, an intermediate thermometer that is disposed at an interval on the outlet side of the cooler and that measures the measured intermediate temperature of the strip-shaped metal material and a winding thermometer that determines the measured winding temperature, A means for obtaining a recuperation temperature difference which is a difference between the measured intermediate temperature and the measured winding temperature, and a target intermediate temperature at an intermediate thermometer installation position from the sum of the reheat temperature difference and a predetermined target winding temperature. A cooling means for controlling the cooling machine so as to reduce a difference between the target intermediate temperature and the actually measured intermediate temperature of the intermediate thermometer.