JPH08252625A - Method for controlling coiling temperature in hot rolling - Google Patents

Abstract

PURPOSE: To control the temp. of a sheet to the target coiling temp. by small quantity of calculation with high accuracy even when sheet passing velocity is rapidly changed at the time of coiling a rolled sheet with a coiler. CONSTITUTION: In this method for controlling coiling temp. in hot rolling, at the time of making the rolled sheet to which finish rolling is applied in a hot rolling process enter cooling equipment and cooling it down to a prescribed coiling temp. by injecting cooling water on the rolled sheet, the injecting quantity (injection distance) of cooling water to every virtual sheared sheet which is set onto the rolled sheet is estimated based on measured temp. on the outlet side of a finishing mill and preset sheet passing speed and water is injected onto the virtual sheared sheet. The quantity of injection (completing position of water injection) 6 to the virtual sheared sheet whose sheet passing speed is linearly accelerating like the B is simply set to a value which is the quantity of water injection before acceleration multiplied by acceleration rate. Error 7 due to difference between the quantity 6 of water injection and the target quantity 5 of water injection is reduced in the inclination and magnitude, so the quantity of water injection for compensating the error is strictly calculated because a period Δt which is calculated by allowable error ΔT is lengthened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling coiling temperature control method, and particularly to hot rolling suitable for winding a rolled plate such as a rolled steel plate produced by a hot rolling process into a coiler. The present invention relates to a winding temperature control method.

[0002]

2. Description of the Related Art Generally, in hot rolling, a steel plate rolled to a desired thickness by a finishing mill is finally wound around a coiler, but the product quality is maintained during the winding. In order to prevent this, cooling to a predetermined winding temperature is performed. The control of the winding temperature in this hot rolling process is usually performed by a cooling facility arranged between the finish rolling mill and the coiler.

FIG. 10 conceptually shows the positional relationship between these equipments. Cooling is provided between the final stand SF of the finish rolling mill and the coiler 10 for winding the steel sheet S rolled by the finish rolling mill. A facility 12 is provided, and between the final stand SF and the cooling facility 12, the finish rolling mill outlet temperature (F
The FDT meter 14 for measuring the inishar Delivaly Temperature (hereinafter, also referred to as FDT) is also used as the cooling equipment 1.
The coiling temperature (Coiling Tempe) is between the coiler 2 and the coiler 10.
CT meter for measuring rature (hereinafter also referred to as CT) 1
6 are installed.

Inside the cooling equipment 12, as shown in the perspective view in FIG. 11, a large number of water injection headers 18 (steel plates S) are provided above and below the steel plate S traveling in the direction of the arrow. (Indicated by a straight line extending in the width direction) is provided. In each of these water injection headers 18, by opening and closing a valve (actuator) 20, a plurality of nozzles 18A (shown by seven straight lines perpendicular to the upper surface or the lower surface of the steel plate S in the drawing) to cooling water (in the drawing, a shaded pattern). (Shown in FIG. 4) is sprayed (water-filled) on both front and back surfaces of the steel plate S, and all the water-filling headers 18 have substantially the same cooling capacity.

The steel sheet S is cooled by the cooling equipment 12 and CT
When the CT measured by the total 16 is controlled to be constant, conventionally, as shown in FIG. 12, a virtual cutting plate i, i + 1, i + 2, ... Considering the above, the temperature of the steel plate S is actually measured (or predicted) by the FDT meter 14 for each virtual cutting plate, and it is appropriate in consideration of the FDT and the passing speed variation predicted from the schedule until the coiler 10 winds the coil. The amount of water injection (cooling amount) is estimated, and the valve 20 is opened / closed in accordance with the timing at which the virtual cutting plate arrives so as to reach the amount of water injection (actually, there is a response delay such as opening / closing of the valve, so that appropriate The water injection distance (the number of headers 18 in the cooling water jetting state in the cooling equipment 12) is adjusted.

By the way, generally, in a finish rolling mill in a hot rolling line, rolling is performed while changing the speed according to a rolling schedule represented by a rolling speed which changes with time as shown in FIG. That is, after the start of rolling, the steel sheet S is rolled at a constant low speed A until the tip of the coiler 10 is wound on the coiler 10, and thereafter, in order to reduce the rolling time, the accelerated state B of a substantially constant acceleration rate is followed by the high speed state C. After maintaining that state, the state is reduced to a low speed state E through a deceleration state D having a substantially constant deceleration rate in order to adjust the coil shape and the like, and the rolling is finished after a lapse of a predetermined time.

When finish rolling according to the rolling schedule shown in FIG. 13, the steel sheet S passing through the inside of the cooling equipment 12
Also, the rolling speed will change substantially the same as the rolling speed shown in FIG. Therefore, when the FDT of the virtual cutting plate measured by the FDT meter 14 is constant, the cooling amount (cooling time: pouring time of cooling water to the virtual cutting plate) required to obtain the same CT is determined. Since it may be constant, the valve 20 is opened and closed in accordance with the variation of the speed at which the steel sheet S passes through the cooling facility 12 (passing speed), that is, the water injection distance is proportional to the speed variation of FIG. You can control it.

However, the FDT actually measured is a skid mark SM in which the temperature of the steel plate S periodically fluctuates in the length direction (from the tip to the tail end) with respect to the target FDT, as conceptually shown in FIG. , Run-down RD in which the tail end side has a temperature lower than that of the tip end side, and conversely, run-up RU in which the tail end side has a higher temperature than that of the tip end side, and the like. Here, the skid mark SM is a periodic temperature fluctuation that occurs corresponding to the skid position because the slab is placed on the skid and heated in a heating furnace (not shown) before finish rolling, and the rundown RD is a variation due to the fact that when rolling the slab discharged from the heating furnace, the closer to the tail end, the larger the degree of cooling because the rolling start is delayed, and the run-up RU is because the rolling speed is accelerated. In addition, there is a decrease in the degree of cooling during rolling in the finish rolling mill, which is a variation caused by exceeding the degree of rundown.

As described above, since the FDT actually measured on the exit side of the finish rolling mill is actually fluctuating, the virtual cutting plates i, i +
For each 1, i + 2, ..., Measured FDT and speed fluctuation until winding (including difference in air cooling amount due to difference in strip running time)
The water injection distance estimated based on the
_As shown in FIG. 15, the relationship with _i , t _{i + 1} , t _{i + 2} , ... Must be changed for each virtual cutting board.

FIG. 16 shows an FD for each virtual cutting plate when the finish rolling is executed according to the schedule shown in FIG.
Water injection distance (cooling facility 12 obtained by estimation calculation based on FDT actually measured by the T-meter 14 and predicted strip passing speed, etc.
2 is a graph conceptually showing the number of water injection headers for opening the valve in relation to elapsed time, that is, for each virtual cutting plate.
In this figure, the shorter the elapsed time is, the virtual cutting plate number i
Since the number is low, the water injection distance is displayed on the left side as the number of the virtual cut plate is smaller.

As described above, the water pouring distance is estimated and calculated for each virtual cutting plate, and the water pouring distance (water pouring amount) is calculated by opening and closing the valve at a timing corresponding to the virtual cutting plate based on the estimation result. In the rolling schedule shown in FIG. 13 in the rolling schedule shown in FIG.
The case where the speed changes from a low constant speed state to a high constant speed state with a linear acceleration rate will be examined in more detail.

As shown in Graph 1, FIG. 17 shows the strip running in the case where the rolling speed is linearly accelerated from A to B to C and then to a high speed state as in the rolling schedule shown in FIG. The relationship between speed, water injection distance (water injection end position in the figure), and winding temperature error is shown in a simplified manner, ignoring thin FDT fluctuations. From constant speed A to acceleration B to constant speed C Even if the speed is changed to the state, if the water injection distance is the same as in Graph 2 without changing, the coiling temperature due to the coiler will have an error as shown by Graph 3 in the broken line. Become. This error becomes larger as the speed difference before and after acceleration becomes larger, and sometimes becomes 100 to 200 ° C. In order to make this error approximately 0 ° C. as shown in Graph 4, it is necessary to correspond to the temperature fluctuation in Graph 3. The water injection distance setting must be changed as shown in Graph 5. Although such a change in the setting of the water injection distance is the reverse of the phenomenon, it is also necessary when decelerating as C → D → E in FIG.

[0013]

However, in order to properly estimate and change the water injection distance according to the speed fluctuation as described above, the allowable winding temperature error is ΔT [° C]. For example, it is necessary to estimate and calculate the water pouring distance such that the actual error falls within this range by performing complicated calculation processing such as repeated convergence calculation in a short time (Δt) for each virtual cutting plate.

That is, in the constant speed states A and C, since the winding temperature error is relatively small, there is no problem, but the water injection distance (water injection amount) according to the speed fluctuation is estimated for each virtual cutting plate, When the cooling water is sprayed from the water injection header 18 to the steel plate S to control the winding temperature, even if there is no large fluctuation in the FDT, if an equal control accuracy is always attempted, the acceleration rate of the strip running speed is increased. The larger (or the deceleration rate) or the plate passing speed itself, the smaller the length of the virtual cutting plate, which is the unit of calculation, must be reduced.

As a result, the calculation cycle Δt becomes short, and the calculation processing by the CPU (central processing unit) of the controller for controlling the cooling equipment may not be in time, which makes it impossible to control the winding temperature with high accuracy. There is. This problem becomes more serious as the temperature calculation model formula (estimation formula) used for estimating the water injection amount becomes complicated, and the amount of calculation processing by the CPU increases accordingly. This means that the calculation cycle has a limit determined by the calculation processing capacity of the controller and the calculation amount required for one estimation.

The present invention has been made to solve the above-mentioned conventional problems, and when winding a rolled sheet to be hot-rolled according to a schedule with a coiler, even if the stripping speed changes abruptly, An object of the present invention is to provide a hot rolling coiling temperature control method capable of controlling the coiling temperature to a target coiling temperature with high accuracy without increasing the calculation processing capacity.

[0017]

Means for Solving the Problems The present invention, when a rolled sheet finish-rolled in a hot rolling process is introduced into a cooling facility and cooling water is poured into the rolled sheet to cool it to a predetermined coiling temperature,
Estimate the injection amount of cooling water for each virtual cutting plate of a predetermined length that is virtually set on the rolling plate based on the measured finish rolling mill outlet temperature and the preset strip passing speed, and estimate In the hot rolling coiling temperature control method of pouring the cooling water of the specified water injection amount into the virtual cutting plate in accordance with the timing when the corresponding virtual cutting plate arrives, pouring is performed on the virtual cutting plate whose passing speed is fluctuating. By simply setting the water amount to a value obtained by multiplying the water injection amount before fluctuation, which is pre-estimated and calculated based on the actual or predicted finish rolling mill outlet temperature and the set strip passing speed, by the acceleration rate or deceleration rate. The above-mentioned problems are solved.

According to the present invention, in the above winding temperature control method, the amount of water injection is the water injection distance, and the simple setting of the water injection distance for each virtual cutting plate is performed so that the water injection time is constant. Is.

According to the present invention, in the above winding temperature control method, the water injection distance is the number of operating water injection headers arranged in the cooling equipment.

According to the present invention, in the above-described winding temperature control method, the water injection amount to the virtual cutting plate in which the passage speed is linearly varying is multiplied by the water injection amount before the variation by a constant acceleration rate or deceleration rate. The values are simply set to different values.

In the winding temperature control method according to the present invention, when the strip passing speed is changed from a constant speed to a constant speed after changing at a constant acceleration rate or deceleration rate, the cooling equipment enters the cooling facility after the start of the change. Before the fluctuation is completed, the water injection distance to the virtual cutting plate within the range of the rolling plate that comes out of the equipment is the same as the trajectory of the virtual cutting plate within the above range moving in the cooling equipment drawn with respect to the time axis. Set a value on a straight line that passes through the intersection with a straight line parallel to the time axis that corresponds to the water injection distance in the same facility that is preliminarily calculated for the virtual cut plate and that has a slope that corresponds to the acceleration rate or deceleration rate. It was done like this.

According to the present invention, in the winding temperature control method, the straight line having a slope corresponding to a constant acceleration rate or deceleration rate and the constant speed before and after the preliminarily calculated fluctuation are set. 2 parallel to the time axis corresponding to the water injection distance
The intersection with the straight line of the book is set as the change start point and the change end point of the water injection distance, respectively.

Further, according to the present invention, in the above-mentioned winding temperature control method, it is predicted that the virtual cutting plate whose passing speed is fluctuating will be generated from the measured finish rolling mill outlet temperature and the simply set water injection amount. The error from the target winding temperature is compensated for in the adjustment zone provided behind the control zone for injecting the cooling water of the simply set water injection amount.

[0024]

In the present invention, the water injection amount for each virtual cutting plate whose passage speed is fluctuating is simply set to a value obtained by multiplying the water injection amount before the change by the acceleration rate or the deceleration rate. The FDT and the strip running speed, which are actually measured or predicted, are used to estimate the previous water injection amount with high accuracy in advance, and during the change, the water injection amount before the change is the acceleration rate known from the rolling schedule. Alternatively, since it suffices to multiply by the deceleration rate, it is possible to significantly reduce the calculation amount as compared with the case where the estimation calculation that takes time is performed by the same method for each virtual cutting plate.
Therefore, even when the rate of change of the strip passing speed is large, it is possible to correct the winding temperature corresponding to the change in speed without increasing the processing capacity of the controller.

Further, in the present invention, as in claim 2,
When the water injection amount is the water injection distance and the simple setting of the water injection distance for each virtual cutting plate is performed so that the water injection time is constant, the water injection distance for the virtual cutting plate during speed fluctuation (for example,
The number of operating water injection headers that have substantially the same water injection capacity installed in the cooling equipment is defined as "constant water injection time".
Introducing the precondition, the actuator for correcting the water injection distance by a simple formula using the water injection time and the acceleration rate or deceleration rate as parameters (for example, turning on the water injection from the water injection header as in claim 3). -It can be easily set by deciding the timing (time) for operating the valve for turning off, and operating the actuator in accordance with the timing.

Specifically, the slope r [m / s] of the water injection distance is obtained by the following equation (1), and one water injection is obtained by the following equation (2) from this inclination r and the distance ΔL between the water injection units. The timing for operating the actuator can be set at time intervals τ for increasing or decreasing the unit (water injection header).

R = α · Δt _w · C (1) where α: acceleration / deceleration rate [m / s ² ] Δt _w : water injection time [s] C: correction coefficient τ = ΔL / r (2)

Further, in the present invention, as in claim 4,
When simply setting the water injection amount for the virtual cutting plate in which the passing speed is changing linearly to the value obtained by multiplying the water injection amount before the change by a constant acceleration rate or deceleration rate, Since the set water injection amount can be obtained by a simple proportional calculation, it becomes easier for the controller to perform the calculation process. Therefore, it is possible to very effectively cope with monotonous and continuous fluctuations in acceleration or deceleration, such as speed fluctuations set as a rolling schedule.

In the present invention, as in claim 5,
When changing the strip running speed from a constant speed to a constant speed after changing it at a constant acceleration rate or deceleration rate, the virtual cutting is within the range of the rolling plate that enters the cooling equipment after the start of the variation and exits from the equipment before the completion of the variation. The water pouring distance to the plate, a trajectory that moves in the cooling equipment that any virtual cutting plate within the above range draws with respect to the time axis,
Set with a value on a straight line that passes through the intersection point with a straight line parallel to the time axis corresponding to the water injection distance in the same facility that is estimated and calculated in advance for the same virtual cut plate and that has a slope corresponding to the acceleration rate or deceleration rate In this case, the amount of water to be injected into the virtual cutting plate during the passage speed can be set based on the water injection distance obtained by the strict estimation calculation, and therefore the target water injection distance calculated assuming that FDT is substantially constant. Since it can substantially match with, it is possible to control the temperature with extremely high accuracy.

Further, at this time, as in claim 6, the straight line having a slope corresponding to a constant acceleration rate or deceleration rate, and water injection set at a constant speed before and after fluctuation which is estimated and calculated in advance. When setting the intersection of two straight lines parallel to the time axis corresponding to the distance as the change start point and the change end point of the water injection distance, the change start point of the water injection distance with respect to the fluctuation of the strip running speed. Since the end point can be set appropriately, it is possible to perform highly accurate temperature control from the beginning to the end while varying the strip passing speed.

Further, in the present invention, the error from the target winding temperature, which is predicted to be generated from the finish rolling mill outlet temperature measured while the strip running speed is fluctuating, and the simply set water injection amount, is simply set as the water injection amount. When compensating in the adjustment zone provided after the control zone for injecting the cooling water, the amount of water injection set during fluctuation of the strip running speed is calculated by the above-mentioned simple calculation, and even if an error occurs due to cooling. Since the cooling that requires a rapid correction of the water injection amount in a short time has already been completed based on the above-described simple calculation, both the inclination and the magnitude of the fluctuation are small. Therefore, the calculation cycle for calculating the water injection amount that compensates for the above error can be lengthened, so that the water injection amount can be calculated using a strict estimation formula, and the error can be calculated by applying the water injection amount. Since it can be eliminated, extremely accurate winding temperature control becomes possible.

[0032]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a drawing corresponding to FIG. 10 conceptually showing the arrangement of cooling equipment applied to the first embodiment according to the present invention, and FIG. 2 is a winding temperature control of the present embodiment. 18 is a drawing conceptually showing the characteristics of the method and corresponding to FIG.

As in the conventional case shown in FIG. 10, the cooling equipment 12 applied to the present embodiment has a large number of water injection headers (water injection units) 18 therein as shown in FIG. 11. It is arranged in the traveling direction of the steel plate S, and by opening and closing the valve 20, it is possible to correct the water injection distance (water injection amount) of the cooling water from the water injection header 18, and the entire length of the cooling facility 12 in the longitudinal direction. The cooling zone over
Control zone 12A on the upstream side and adjustment zone 12B on the downstream side
The water injection distance in each zone is adjusted independently.

Similar to the case of FIG. 17, the characteristic of the winding temperature control method of the present embodiment is that the passing speed varies from A to C after acceleration B as shown in FIG. Will be explained.

In this embodiment, in the control zone 12A, the water injection distance is set so as to change with respect to the virtual cut plate as shown in Graph 6, and the valve is opened / closed in accordance with the timing when the corresponding virtual cut plate arrives. Header 18 to go and pour water
Is adjusted and corrected so that the water injection distance is set for each virtual cutting plate, and the steel plate S is cooled.

That is, as shown in Graph 6, when the strip running speed is in the low speed state A, the FDT is actually measured as in the conventional case, and the water injection distance is estimated and calculated using the actually measured FDT to set it. During the acceleration state B after the passage speed starts linear acceleration, the water injection distance is set by simple calculation (simple setting), and in the high speed state C, the water injection distance at the time of completion of acceleration is set.

The simple setting of the water injection distance during acceleration (speed fluctuation) is performed as follows. The FD measured (or predicted) in advance for the water injection distance at low speed A that is set before acceleration
Accurate estimation calculation is performed based on T, the strip speed determined from the schedule, and the like. This estimation calculation is based on the flow shown in the block diagram of FIG. 3, and ON / OFF of the water injection header determined from the steel plate specifications (thickness, etc.), FDT, and arbitrary water injection distance in the model formula (complex is omitted). The temperature T of the target point is calculated by applying the combination of the above and the moving time in the cooling equipment, and the calculated temperature T and the target temperature T.
It is performed by comparing with ₀ , repeating the temperature calculation while increasing or decreasing the water injection distance until the absolute value of the difference δ converges to a value smaller than the allowable error δ _{0, and} using the water injection distance at the time of convergence as the estimated value. You can

Then, as described above, the water injection distance set for the virtual cutting plate whose plate passing speed is accelerating is "constant water injection time".
Introducing the precondition of (3), the water injection time before acceleration and the acceleration rate (acceleration) are used as parameters to calculate by the simple calculation formula of the formula (1).

The simple setting of the water injection distance is synonymous with setting the water injection distance during acceleration to a value obtained by multiplying the water injection distance before acceleration by a constant acceleration rate. FIG. 4 shows the water injection distance that is simply set in correspondence with FIG.

The water injection distance of the graph 6 shown in FIG.
It can be easily obtained by the method described above, and in the same rolled plate, it only has to be calculated once before acceleration. In FIG. 2, in the graph 5 showing the target water injection distance, the fact that the change start time point 5S is before the acceleration start time point 1S means that the advance is made in consideration of the response delay of the water injection system. In the present embodiment, since the water injection distance during acceleration is simply set as described above, the actual time of changing the water injection distance is 6S.

The change score 6S is set by applying an arbitrary point on the steel plate that enters the cooling equipment after the start of acceleration and leaves the cooling equipment before the end of acceleration and the condition that the water injection time is constant at that point ( As a crossing point between a straight line 6B having a slope that is obtained in advance based on the acceleration rate and a straight line 6A that expresses the water injection distance calculated exactly at a constant low speed, passing through the coordinates (time, position) defined by (water injection end position) The end point 6E of changing the water injection distance can be set as a point on the straight line 6B corresponding to the end point 1E of acceleration.

When the strip running speed changes linearly (linearly) as described above, the water injection distance which changes linearly is set,
Determine the timing (time) to operate the water injection valve so that each water injection distance is reached, and adjust valve 2 according to that timing.
The steel plate S is cooled by opening 0.

By the way, during the speed change, the control zone 12A
Then, when the valve 20 is adjusted so that the water injection distance shown in the graph 6 is obtained, it is possible to eliminate the disturbance caused by the speed fluctuation in the disturbance of the winding temperature control. Similarly, since there is a difference between the target water injection distance shown as graph 5 and the simply set water injection distance shown in graph 6, there is a difference because of the simple setting. An error in the taking temperature (due to other disturbances such as FDT fluctuation and shortening of air cooling time) will occur.

Compared with the temperature change when trying to cope with the setting of the water injection distance in Graph 5, this winding temperature error is
Since both the inclination and the magnitude of the fluctuation are small, as shown in FIG. 17, the frequency of calculation processing required to achieve the control accuracy of the winding temperature within ΔT ° C. is reduced, and the calculation cycle Δt Since it becomes possible to take a long time, it becomes easy to cope with the calculation processing by a complicated estimation formula, and it becomes possible to realize highly accurate control.

In this embodiment, the winding temperature error of graph 7 caused by the above-mentioned simple setting method is corrected in the adjusting zone 12B provided on the downstream side of the cooling equipment.

In this compensation setting method, for example, for each virtual cutting plate, the current temperature is appropriately calculated based on the actually measured FDT and the actual speed and water injection condition while existing inside the control zone 12A. Error is calculated by estimating the water injection distance (water injection amount) required for correction based on the calculated temperature at the obtained current position and the subsequent planned speed, material, etc., and setting the water injection distance as the water injection amount in the adjustment zone 12B. To eliminate. The calculation of the water injection distance here can be similarly performed according to the above-described calculation procedure by replacing “FDT” in (2) with “calculated temperature at the current position” in the flow shown in FIG. it can.

FIG. 1 when the method of this embodiment is applied.
FIG. 5 conceptually shows the water injection distance set for each virtual cutting plate corresponding to 6. “Water injection by simple calculation” performed in the adjustment zone shown in this figure means that water is previously supplied at some fixed water injection distance so that the water injection distance can be increased or decreased when the water injection distance is compensated.

FIG. 6 shows the winding temperature control according to this embodiment,
It is also a conceptual illustration of the relationship between the virtual cutting plate moving from the FDT meter position to the CT meter position and the temperature change in the cooling equipment 12.

In the figure, a thick solid line shows a temperature change according to the embodiment, and a thin solid line shows a target temperature change when cooling control is performed while executing a precise estimation calculation in a short cycle. Further, in the upper part of the figure, the water injection distance and the compensation zone 12B simply set in the control zone 12A of the cooling facility 12 are shown.
The water injection distance that is set with high precision compensation is shown as the number of water injection headers (marked with ◯) in the water injection ON state. In addition,
The cross mark represents the water injection header in the water injection OFF state.

In FIG. 6 described above, the virtual cutting plate whose temperature is measured by the FDT meter 14 is simply set in the control zone 12A, is water-cooled by the valve-opening water-filling header 18, and the target temperature generated due to the simple setting is set. The error ΔTe is calculated as follows:
It is shown that the problem is solved by the compensation setting (indicated by a black circle) in 2B.

In this case, in the compensation zone, water injection is turned on.
A standard is determined for the number of headers 18 to be turned on. For example, when the temperature error is an average value, n headers 18 are turned on, and the cooling amount is reduced by reducing the number of headers turned on to less than n. You can also

FIG. 7 shows the temperature change of the virtual cutting plate when the error ΔTe is eliminated in the compensation zone 12B as in the case of FIG. 6 described above. This is an example of a case where they match.

By cooling so that the temperature changes shown in FIGS. 6 and 7 described above, the graph 6 of FIG. Due to the simple linear setting, FD
Even if there is no change in T, it is possible to easily prevent the occurrence of the error ΔTe that is inevitably generated.

According to this embodiment described in detail above, for example,
In hot rolling coiling temperature control for ordinary steel, there are cases in which it is difficult to execute complex processing in a proper cycle, which was caused by the computational load on the CPU of the conventional controller. However, it is possible to eliminate this, and by performing high-precision calculation processing only for the adjustment zone at appropriate timing, it is possible to achieve high-precision winding temperature control.

FIG. 8 is a graph corresponding to FIG. 2 showing the water injection distance set in the second embodiment according to the present invention. In this embodiment, as in the first embodiment, the graph 1
As shown in A → B → C, when changing the strip running speed from a low constant speed to a high constant speed after changing it at a constant acceleration rate, the cooling equipment enters into the cooling equipment after the fluctuation starts, The trajectory (moving distance) 7 of the virtual cutting plate within the above range that moves in the cooling equipment drawn with respect to the time axis, and the virtual cutting plate within the range of the rolled plate A straight line that passes through the intersection X1 with the straight line 8 parallel to the time axis corresponding to the water injection distance (water injection end position starting from the inlet of the cooling equipment) that has been estimated and calculated for the plate, and that has a slope proportional to the acceleration rate Set at a value above 6B.

In other words, the arbitrary point X1 is the timing at which the arbitrary point on the rolling plate that enters the cooling equipment after the start of acceleration and exits the cooling equipment before the end of acceleration reaches the cooling (water injection) end position at that point. It is defined by the elapsed time and the position in the cooling equipment.

Further, when the changing water injection distance is set as described above, the starting point 6S and the end point 6E for changing the water injection distance are set.
Is a straight line 6B having a slope corresponding to the acceleration rate and passing through X1 and a graph 6 parallel to the time axis corresponding to the water pouring distance set at the constant speed before and after the fluctuation calculated in advance. Two straight lines 6A passing through arbitrary points X2 and X3
And 6C, respectively.

As in the case of the first embodiment, the water injection distances for the three arbitrary points (virtual cutting planes) X1, X2, X3 on the graph 6 are exactly estimated in advance according to the flow shown in FIG. It can be calculated.

According to the present embodiment, as shown in the figure, there is a slight difference in the water injection distance with respect to the virtual cutting plate between the start point 6S and the end point 6E of the change of the water injection distance. It can be roughly matched to the graph 5 showing the target water injection distance obtained based on exact calculation as the FDT is constant.

Therefore, according to this embodiment, since the water injection distance is set in the graph 6 shown in the lower part of FIG. 8, slight temperature errors 9A and 9B which occur near the start point 6S and the end point 6E are set. Together with a slight temperature error (not shown) caused by FDT fluctuation or the like, together with the adjustment zone 12
It is possible to control the rolled plate to the target winding temperature with high precision by increasing or decreasing the amount of water injection in B to adjust.

FIG. 9 is a drawing corresponding to FIG. 6 when the winding temperature control of the third embodiment according to the present invention is applied. In this embodiment, the cooling facility 12 is not divided into zones as in the first embodiment, and the water injection distance compensation setting (indicated by black circles) is performed simultaneously with the simple setting by increasing the number of headers in the middle.

The present invention has been specifically described above, but the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the invention.

For example, in the above embodiment, the case where the water injection amount is the water injection distance has been described, but the water injection amount may be corrected by adjusting the opening degree of the actuator such as the nozzle.

Moreover, the actuator for allowing the injection of the cooling water is not limited to the valve.

[0066]

As described above, according to the present invention,
When rolling a rolled sheet that is hot-rolled according to a schedule with a coiler, even if the stripping speed changes abruptly, control the target winding temperature with high accuracy without increasing the calculation processing capacity of the controller. You can

[Brief description of drawings]

FIG. 1 is an explanatory view showing a positional relationship of cooling equipment in a hot rolling line applied to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a winding temperature control method of the present embodiment.

FIG. 3 is a block diagram showing the procedure for estimating and calculating the water injection distance.

FIG. 4 is a diagram showing the features of this embodiment.

FIG. 5 is an explanatory view conceptually showing the water injection distance over the entire length when this embodiment is applied.

FIG. 6 is a diagram showing an example of a temperature change of a virtual cutting plate when this embodiment is applied.

FIG. 7 is a diagram showing another example of the temperature change of the virtual cutting plate when the present embodiment is applied.

FIG. 8 is a diagram for explaining a winding temperature control method according to a second embodiment.

FIG. 9 is a diagram showing an example of a temperature change of a virtual cutting plate when the third embodiment is applied.

FIG. 10 is an explanatory diagram showing a layout relationship of conventional cooling equipment.

FIG. 11 is a perspective view showing an outline of a configuration of a main part inside a cooling facility.

FIG. 12 is a diagram for explaining a virtual cutting board.

FIG. 13 is a diagram showing speed fluctuations due to a general rolling schedule.

FIG. 14 is a diagram for explaining the cause of FDT fluctuation.

FIG. 15 is a diagram for explaining a setting situation of a conventional water injection distance.

FIG. 16 is a diagram corresponding to FIG. 4, showing a water injection distance set in a cooling facility in conventional finish rolling.

FIG. 17 is a diagram for explaining the problems of the conventional winding temperature control method.

[Explanation of symbols]

 10 ... Coiler 12 ... Cooling equipment 12A ... Control zone 12B ... Adjustment zone 14 ... FDT meter 16 ... CT meter 18 ... Water injection header 20 ... Valve

Claims (7)

[Claims] 1. When a rolled plate finish-rolled in a hot rolling process is introduced into a cooling facility and cooling water is poured into the rolled plate to cool it to a predetermined coiling temperature, For each virtual cut plate of a predetermined length virtually set on the plate, it is estimated based on the measured finish rolling mill outlet temperature and the preset strip passing speed, and the estimated amount of cooling water is In the hot rolling coiling temperature control method in which water is poured into the virtual cutting plate at the timing when the corresponding virtual cutting plate arrives, the water injection amount for the virtual cutting plate whose striping speed is fluctuating is measured or predicted. A hot rolling winding characterized by simply setting a value obtained by multiplying the water injection amount before fluctuation calculated in advance based on the exit side temperature of the finish rolling mill and the set strip passing speed by the acceleration rate or deceleration rate. Temperature control method. 2. The hot rolling coiling temperature according to claim 1, wherein the water injection amount is a water injection distance, and the water injection distance is simply set for each virtual cutting plate so that the water injection time is constant. Control method. 3. The hot rolling coiling temperature control method according to claim 2, wherein the water injection distance is the number of operating water injection headers arranged in the cooling equipment. 4. The method according to claim 1, wherein the water injection amount for the virtual cutting plate in which the passage speed is linearly changing is simply set to a value obtained by multiplying the water injection amount before the change by a constant acceleration rate or deceleration rate. A hot rolling coiling temperature control method characterized by: 5. The method according to claim 1, wherein when the strip running speed is changed from a constant speed to a constant speed after being changed at a constant acceleration rate or deceleration rate, the cooling equipment enters into the cooling equipment after the start of the variation and the Estimate the water injection distance for the virtual cut plate within the range of the rolled plate to be projected in advance on the trajectory of the virtual cut plate within the above range moving in the cooling equipment drawn with respect to the time axis and the virtual cut plate A hot work characterized by setting a value on a straight line that passes through the intersection with a straight line parallel to the time axis corresponding to the water injection distance in the same facility and has a slope corresponding to the acceleration rate or deceleration rate Rolling winding temperature control method. 6. The straight line having a slope corresponding to a constant acceleration rate or deceleration rate according to claim 5, and a time corresponding to a water injection distance set at a constant speed before and after fluctuation which is estimated and calculated in advance. A hot rolling coiling temperature control method, characterized in that an intersection between two straight lines parallel to an axis is set as a change start point and a change end point of a water injection distance, respectively. 7. The error from the target winding temperature, which is predicted to occur from the measured finish rolling mill outlet temperature and the simply set water injection amount, for the virtual cutting plate in which the strip passing speed is fluctuating. Is compensated in an adjustment zone provided behind a control zone for injecting a cooling water of a simply set water injection amount, a hot rolling coiling temperature control method.