JPH11124635A - Method of controlling continuous annealing furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method of a continuous annealing furnace in which the productivity is improved even in the case the capacity of an accumulator is low. SOLUTION: In the period (period (a)) when the leading part of a plate material passes through the heating furnace, the furnace temp. TF2, nozzle pressure P2 and passing-through speed LS2 in the furnace are set. Successively, at the time when the intermediate part of the plate material passes through the furnace, nozzle pressure P1, passing-through speed LS1 in the furnace and furnace temp. TF1, are set. Successively, the nozzle pressure and the passing-through speed in the furnace are set so that the furnace temp. TM becomes the constant according to the actual measured value TFact of the furnace temp. Thereafter, at the time when the latter half of the intermediate part of the plate material passes through the heating furnace (the starting point of transient range Ct), the furnace temp. TF2 is set by a furnace temp. adjusting instrument. Thereafter, in the period (period (c)) when the trailing part of the plate material (and the leading part of the following material) passes through the annealing furnace, the furnace temp. nozzle pressure and passing-through speed in the furnace become the furnace temp. TF2, nozzle pressure P2 and passing-through speed LS2 in the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an annealing furnace when a metal plate is annealed using a floater type continuous annealing furnace, and more particularly to a method for continuously annealing a sheet by changing the speed of passage of the sheet in the furnace. The method of controlling the continuous annealing furnace in the case.

[0002]

2. Description of the Related Art FIG. 6 is a schematic view showing a conventional continuous annealing furnace. The plate 2 is wound around the payout reel 14 in a roll shape, and the heating furnace 1 that anneals the plate 2 is disposed downstream of the plate 2 discharged from the payout reel 14 in the traveling direction. A take-up reel 15 on which the annealed plate material 2 is wound is disposed downstream of the heating furnace 1. In addition, between the payout reel 14 and the heating furnace 1 and between the heating furnace 1 and the take-up reel 15, respectively, the inlet accumulator 11 for accumulating the plate material 2 paid out from the payout reel 14, and An outlet accumulator 10 for accumulating the plate material 2 sent from the heating furnace 1 is arranged, and the feeding of the plate material 2 is adjusted by these accumulators 10 and 11. Above and below the plate 2 passing through the heating furnace 1, nozzles 16 of a floater for blowing a heating gas to the plate 2 are attached.

In the continuous annealing furnace configured as described above, first, the sheet material 2 is paid out from the payout reel 14 and stretched around the inlet accumulator 11, and then the heating furnace 1
Sent to Then, the plate material 2 is annealed in the heating furnace 1. Thereafter, the plate material 2 sent from the heating furnace 1 is
After being stretched on the outlet accumulator 10, the take-up reel 1
5 is wound up.

[0004] When all the plate materials 2 wound around the payout reel 14 are paid out, only the rear end of the plate material 2 is stopped, and the reel 14 is replaced with a new reel (not shown) on which the unannealed plate material is wound. And the rear end of the plate 2 is connected to the front end of the plate wound on the new reel. At this time, since the plate material 2 having a predetermined length is accumulated in the inlet-side accumulator 11, the passage of the plate material 2 in the heating furnace 1 and the winding of the plate material 2 onto the take-up reel 15 are stopped. Not
The plate material 2 can be continuously annealed.

When the leading end of the plate 2 reaches the take-up reel 15, the leading end of the plate 2 is separated from the trailing end of the preceding plate, and the take-up reel 15 is separated from the empty reel on which the plate is not wound. After replacement, the leading end of the plate material 2 is connected to the empty reel, and winding on the winding reel 15 is started. When the reel is replaced, the work of winding the plate material on the reel is interrupted, but the plate material of a predetermined length can be accumulated in the outlet accumulator 10, so that the passage of the plate material in the heating furnace 1 can be performed. In addition, the plate material can be continuously annealed without stopping the payout of the plate material from the payout reel 14.

However, during the continuous annealing, if the capacity of the entrance accumulator 11 and the exit accumulator 10 is low, that is, if the length capable of accumulating the plate 2 is not sufficient, depending on the material of the plate 2 It is necessary to change the passing speed of the plate material in the heating furnace 1. FIG.
FIG. 4 is a control timing chart according to a conventional annealing method when the capacity of the accumulator is low. FIG.
, A period a indicates a period during which the leading end of the plate passes through the heating furnace, and a period b indicates a period during which the middle portion of the plate passes through the heating furnace. A period c indicates a period in which the rear end of the plate material passes through the heating furnace.

When the inlet accumulator 11 and the outlet accumulator 10 have low capacity, as shown in FIG. 7, the speed at which the front and rear ends of the plate 2 pass through the heating furnace 1 (the front and rear ends of the plate). Is set to be lower than the speed at which the intermediate portion of the plate material 2 passes through the heating furnace 1 (the in-furnace speed LS1 of the intermediate plate material).
Thereby, the time required for the connection between the plate 2 and the preceding material and the connection between the plate 2 and the succeeding material are secured.

In this case, in order to maintain the temperature of the plate 2 at a constant temperature (plate temperature TM), the temperature of the plate 2 is maintained while the temperature in the heating furnace 1 is maintained at a constant temperature (furnace temperature TF). The nozzle pressure (nozzle pressure P2 at the front and rear end portions of the plate material) when the front end portion and the rear end portion pass through the heating furnace 1 is the nozzle pressure (nozzle pressure when the intermediate portion of the plate material 2 passes through the heating furnace 1). Is set to be lower than the nozzle pressure P1) of the section. The nozzle pressure refers to the pressure of the gas when the heating gas is blown from the nozzle 16 of the floater to the plate material 2. A constant value (plate temperature TM) between the furnace temperature when the leading end and the rear end of the plate pass through the heating furnace 1 and the furnace temperature when the middle part of the plate passes through the heating furnace 1 This is because, in the floater annealing furnace, the actual furnace temperature is unlikely to change even if the set temperature inside the furnace is changed.

FIG. 8 is a graph showing the relationship between the passage speed in the furnace and the nozzle pressure, with the passage speed in the furnace on the vertical axis and the nozzle pressure on the horizontal axis. In FIG. 8, a solid line 20 shows the relationship between the in-furnace passage speed and the nozzle pressure when the furnace temperature is increased to the maximum capacity of the heating furnace, and a solid line 21 shows a relationship between the in-furnace passage speed and the nozzle pressure when the furnace temperature is TF. Shows the relationship. FIG. 8 shows the in-furnace speed LSsp at the time of plate connection and the in-furnace speed at the time of plate connection when the furnace temperature was increased to the maximum capacity of the heating furnace and the nozzle pressure was set to a minimum value (minimum nozzle pressure Pmin). This shows a case where the relationship with LS2max satisfies LSsp <LS2max. At this time, if the nozzle pressure is less than the minimum nozzle pressure Pmin, the plate material cannot be smoothly passed through the heating furnace 1, so that the nozzle pressure P2 at the front and rear ends of the plate material needs to be Pmin or more. Further, the in-furnace speed LSsp (m / min) at the time of connection of the plate material can be calculated by the following equation 1, and the in-furnace speed LS2 of the front and rear end portions of the plate material is obtained.
Must be less than or equal to LSsp.

[0010]

LSsp = L / {(1 + a) × t} where L: Accumulator capacity (m) a: Handling time margin t: Handling time required when connecting boards (minutes)

From these conditions, as shown by ▲ in FIG. 8, the in-furnace speed LS2 at the front and rear ends of the plate material is set to be equal to the in-furnace speed LSsp, and the nozzle pressure P2 is set to the minimum nozzle pressure Pmin. There is a need. Then, since the furnace temperature is constant at TF, by setting the nozzle pressure P1 when the plate material intermediate portion passes through the heating furnace to the maximum nozzle pressure Pmax, as shown by ● in FIG. The internal passage speed LS1 is made as fast as possible.

FIGS. 9 and 10 are graphs showing the relationship between the passage speed in the furnace and the nozzle pressure, with the vertical axis representing the passage speed in the furnace and the horizontal axis representing the nozzle pressure. However, FIG. 9 shows the in-furnace speed LSsp at the time of plate connection and the in-furnace speed at the time of plate connection when the furnace temperature is increased to the maximum capacity of the heating furnace and the nozzle pressure is set to the maximum value (maximum nozzle pressure Pmax). A case where the relationship with LS1max satisfies LSsp ≧ LS1max,
The solid line 22 shows the relationship between the passage speed in the furnace and the nozzle pressure when the furnace temperature is increased to the maximum capacity of the heating furnace. FIG. 10 shows the furnace speed LSsp at the time of plate connection and the furnace speed LS1.
max and the in-furnace speed LS2max satisfy LS1max>
The case where LSsp ≧ LS2max is satisfied is shown, and the solid line 23 shows the relationship between the passage speed in the furnace and the nozzle pressure when the furnace temperature is increased to the maximum capacity of the heating furnace.

As shown in FIG. 9, the furnace speed L at the time of plate connection is shown.
The relationship between Ssp and the furnace speed LS1max at the maximum furnace capacity is
When LSsp ≧ LS1max, the in-furnace speed LS2 at the front and rear end portions of the plate material and the in-furnace speed LS1 at the middle portion of the plate material can be set to the same speed. That is, as shown by ■ in FIG. 9, LS2 = LS1 and P1 = P2 = Pmax
As a result, the plate material can be passed through the heating furnace 1.
Therefore, the furnace temperature can be raised to the maximum capacity of the heating furnace at the time of annealing the front and rear end portions of the plate material and the intermediate portion of the plate material, and the productivity is high.

On the other hand, the relationship among the in-furnace speed LSsp when the plates are connected, the in-furnace speed LS1max in the middle of the plate material at the time of the furnace maximum capacity, and the in-furnace speed LS2max in the front and rear end of the plate material is LS1max> LSsp ≧ L.
In the case of S2max, as shown by △ in FIG. 10, the furnace speed LS2 at the front and rear end portions of the plate material is changed to the furnace speed
Can be set to sp. Further, as shown by a circle in FIG. 10, the in-furnace speed LS1 of the plate material intermediate portion can be set to LS1max. Therefore, even if the in-furnace speed LS2 at the front and rear end portions of the plate material is made lower than the in-furnace speed LS1 at the middle portion of the plate material, and the nozzle pressure P2 at the front and rear end portions of the plate material is made lower than the nozzle pressure P1 at the middle portion of the plate material, The middle nozzle pressure P1 can be set to the maximum nozzle pressure Pmax,
The furnace temperature can be raised to the maximum capacity of the heating furnace, and the productivity is high.

[0015]

However, as shown in FIG. 8, when the relationship between the in-furnace speed LSsp at the time of plate connection and the in-furnace speed LS2max at the maximum furnace capacity satisfies LSsp <LS2max, However, there are the following problems. That is, the in-furnace speed LS2 at the front and rear end portions of the plate material needs to be equal to or lower than the in-furnace speed LSsp at the time of connecting the plate material determined by the above formula 1, and the nozzle pressure needs to be set to a minimum nozzle pressure (Pmin) or more. Therefore, the furnace speed LS2 at the front and rear ends of the sheet material
Need to set LS2 = LSsp. At this time,
The furnace temperature TF is lower than the temperature at the maximum capacity of the heating furnace.
S1 is the furnace speed LS1 in the middle of the plate at the maximum capacity of the heating furnace.
It needs to be set lower than max, and the productivity decreases.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for controlling a continuous annealing furnace which can improve productivity even when the capacity of an accumulator is low. And

[0017]

SUMMARY OF THE INVENTION A method for controlling a continuous annealing furnace according to the present invention is a method for controlling the supply of a sheet material discharged from a discharge reel to a heating furnace while adjusting the supply by an inlet accumulator and a discharge accumulator of the heating furnace. In a method for controlling a continuous annealing furnace, wherein a heating gas is blown from a nozzle to the plate material in the heating furnace to anneal the plate material, and the winding material is wound around a take-up reel, the furnace temperature of the heating furnace and the furnace of the plate material It is characterized in that it is changed in conjunction with the inside passing speed.

The pressure of the nozzle may be raised and lowered in conjunction with the rise and fall of the furnace temperature and the furnace passage speed. Further, in the front end control of the period required to connect the front end of the plate to the preceding plate and the rear end control of the period required to connect the rear end of the plate to the subsequent plate, the furnace The internal temperature TF2, the nozzle pressure P2, and the in-furnace passage speed LS2 are constant, and in the control of the intermediate part thereof, in the rise period of the in-furnace temperature and in-furnace passage speed, the in-furnace temperature and in-furnace passage speed It may have a period in which it is constant at TF1 and LS1, respectively, and a falling period in which the furnace temperature and the furnace passage speed decrease to TF2 and LS2, respectively.

Further, after the leading end of the plate material reaches the take-up reel and starts winding, the traveling speed of the plate material downstream of the discharge-side accumulator in the traveling direction of the plate material and the speed of the plate material in the heating furnace are determined. When the in-furnace passing speed matches, the increase in the in-furnace temperature and the in-furnace passing speed can be started.

Further, the rate of decrease in the temperature of the furnace is estimated based on the measured value of the rate of increase in the temperature of the furnace. Based on the rate of decrease, the temperature of the furnace decreases from TF1 to TF2. Estimate the required plate material passage length in the furnace, and when the furnace passage length matches the remaining length of the plate material remaining on the payout reel, start decreasing the furnace temperature and the furnace passage speed. Is preferred.

In the present invention, since the temperature inside the heating furnace and the speed at which the sheet passes through the furnace are changed in conjunction with each other, the temperature inside the heating furnace when the intermediate portion of the sheet passes is determined by the maximum capacity of the heating furnace. The temperature can be raised to the time. Therefore,
Even if the passing speed in the heating furnace in the middle of the sheet material is increased to the speed corresponding to the furnace maximum capacity, the temperature of the sheet material can be maintained at a constant temperature, so that the case where the sheet material is annealed by the conventional continuous annealing furnace In comparison, productivity can be improved.

When the set temperature of the heating furnace is changed, the temperature in the heating furnace does not change immediately, but the pressure of the nozzle is changed in conjunction with the furnace temperature in the heating furnace and the passage speed of the plate. By doing so, it is possible to set the nozzle pressure suitable for the furnace temperature and the furnace passage speed, and it is possible to improve the annealing efficiency.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for controlling a continuous annealing furnace according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an annealing furnace when a sheet material is continuously annealed by a control method according to an embodiment of the present invention. First, the structure of the annealing furnace will be described with reference to FIG. The sheet material 2 is wound in a roll shape on the payout reel 14, and a heating furnace 1 for annealing the plate material 2 is provided on the downstream side in the traveling direction of the sheet material 2 paid out from the payout reel 14.
Is arranged. A take-up reel 15 on which the annealed plate material 2 is wound is disposed downstream of the heating furnace 1. In addition, between the payout reel 14 and the heating furnace 1 and between the heating furnace 1 and the take-up reel 15, respectively, the inlet accumulator 11 for accumulating the plate material 2 paid out from the payout reel 14, and An outlet accumulator 10 for accumulating the plate material 2 sent from the heating furnace 1 is arranged, and the feeding of the plate material 2 is adjusted by these accumulators 10 and 11.

Above and below the plate 2 passing through the heating furnace 1, a nozzle (not shown) of a floater for blowing a heating gas to the plate 2 is attached. A nozzle pressure detector 4 is connected to this nozzle, and the nozzle pressure detector 4 is connected to a nozzle pressure regulator 7. A furnace temperature detector 3 for detecting a furnace temperature (in-furnace temperature) is attached inside the heating furnace 1, and the furnace temperature detector 3 is connected to a furnace temperature controller 6. Further, between the heating furnace 1 and the outlet accumulator 10, a furnace speed detector 5 for measuring the speed of the plate 2 passing through the heating furnace 1 (furnace passing speed) is arranged. The internal speed detector 5 is connected to a furnace internal speed controller 8. Furthermore, the outlet accumulator 1
0 and the take-up reel 15, the delivery accumulator 1
An output speed detector 12 for measuring the traveling speed (output speed) of the plate material 2 sent from 0 is disposed. Furthermore,
An outside diameter measuring device 13 for measuring the outside diameter of the coil of the plate material 2 wound in a coil shape is attached to the payout reel 14.

The furnace temperature detector 3, furnace temperature controller 6, nozzle pressure regulator 7, furnace speed regulator 8, furnace speed detector 5, outlet speed detector 12, and outer diameter measuring device 13 are set. It is connected to the value calculation device 9. That is, the furnace temperature detected by the furnace temperature detector 3, the passage speed of the plate 2 in the furnace detected by the furnace speed detector 5, the exit speed of the plate 2 detected by the exit speed detector 12, and the like. When the coil outer diameter measured by the outer diameter measuring device 13 and the previously measured material thickness and coil inner diameter are input to the set value calculating device 9, the furnace temperature controller 6 is set based on the input values. , The nozzle pressure regulator 7 and the in-furnace velocity regulator 8 are controlled.

In the annealing furnace configured as described above,
As in the case of the conventional annealing furnace, the plate material 2 is paid out from the payout reel 14, stretched around the entrance accumulator 11, and then sent out to the heating furnace 1. Then, the plate material 2 is annealed in the heating furnace 1. Then, after the plate material 2 sent out from the heating furnace 1 is stretched on the outlet accumulator 10,
It is wound on a take-up reel 15.

Next, a method of controlling the sheet temperature using the annealing furnace will be described below with reference to FIG. In a period (period a) in which the leading end of the plate passes through the heating furnace 1, that is, a period required to connect the leading end of the plate to the preceding plate, the furnace temperature TF2, the nozzle pressure P2, and the furnace speed The LS2 is set in the furnace temperature controller 6, the nozzle pressure regulator 7, and the furnace speed regulator 8, respectively, to control the furnace temperature, the nozzle pressure, and the furnace passage speed. Next, after the winding of the plate material 2 by the take-up reel 15 is started, the in-furnace passing speed measured by the in-furnace speed detector 5 and the exit speed (outside speed of the plate material) measured by the exit speed detector 12 are measured. The set value computing device 9 detects a timing at which the travel speed coincides with the traveling speed. At the timing detected by the set value calculation device 9, the nozzle pressure P1 and the furnace speed L
S1 is set in the nozzle pressure controller 7 and the furnace speed controller 8, respectively, and the furnace temperature TF1 is set in the furnace temperature controller 6. The timing at which the in-furnace speed coincides with the outlet speed is the timing at which the intermediate portion of the plate material 2 passes through the heating furnace in the heating furnace 1.

Incidentally, since the furnace temperature has low followability even when the set value is changed, it takes a predetermined time until the furnace temperature changes from the furnace temperature TF2 to the furnace temperature TF1 and from the furnace temperature TF1 to the furnace temperature TF2. Is required. Hereinafter, these are referred to as a transition region Cf (a period during which the temperature in the furnace and the passage speed in the furnace rise) and a transition region Ct (a period during which the temperature and the passage speed in the furnace fall).

Next, as shown in the flowchart of FIG. 3, the actual measured value TFac of the furnace temperature detected by the furnace temperature detector 3
t is input to the set value calculation device 9 (block 31).
Next, the nozzle pressure Pc and the furnace speed LSc are calculated by the set value calculation device 9 so that the plate temperature TM is constant (block 32). Thereafter, these nozzle pressures Pc
And the furnace speed LSc are set in the nozzle pressure regulator 7 and the furnace speed regulator 8, respectively (block 33). Thereafter, it is detected whether the intermediate portion of the plate 2 is passing through the heating furnace 1 (during passing) (block 34). And
When the intermediate portion of the plate material 2 is passing through the inside of the heating furnace 1 (transient region Cf, steady state and transient region Ct), the operation returns to the operation of the block 31, and the operations from the block 31 to the block 34 are repeated. When the portion passing through the heating furnace 1 becomes the rear end of the plate material 2, these operations are terminated. During this time, the passage speed in the furnace increases to LS1 ′.

When the latter half of the middle part of the plate 2 passes through the heating furnace 1, the furnace temperature TF 2 is set in the furnace temperature controller 6 by the set value calculation device 9. The timing at which the furnace temperature TF2 is set is the start point of the transition region Ct, and the furnace temperature and the furnace passage speed start increasing from this start point. An example of a method for detecting the start point of the transition area Ct will be described below.

The set value calculating device 9 previously sets the transient region Cf
, The time required for the furnace temperature TF2 to rise to the furnace temperature TF1 is measured, and the rate of rise Rf (Rf = change amount of furnace temperature /
Required time). Then, this rising speed Rf
Then, the descending speed Rt is calculated by the following equation (2).

[0032]

Rt = Rf × b + c where b: constant c: constant

Thereafter, as shown in the flowchart of FIG. 4, the actual measured value TFact of the furnace temperature is input to the set value calculating device 9 (block 41). Then, the measured furnace temperature TFac
Corresponding to t, the passage speed L in the furnace is set by the
Sc is calculated at a constant cycle. And the descending speed Rt
Is calculated based on the following equation (block 42): the length Lc of the plate material required for the furnace temperature to decrease from TF1 to TF2. Thereafter, the outer diameter of the plate material coil measured by the outer diameter measuring device 13 is input to the set value calculation device 9 (block 43). Thereafter, the thickness of the plate member 2 and the inner diameter of the plate member coil are input to the set value calculation device 9, and the remaining length of the plate member 2 wound around the payout reel 14 is determined based on the values of the thickness, the inner diameter, and the outer diameter. Lcx is calculated (block 4
4). Thereafter, Lc and Lcx are compared (block 4).
5).

If the relationship of Lcx ≦ Lc is not obtained, the operation returns to the block 41, and the operations from the block 41 to the block 45 are repeated. Also, Lcx ≦ L
When the relationship of c is obtained, it is determined that this timing is the start point of the transition region Ct (block 46). afterwards,
The furnace temperature TF2 is set in the furnace temperature controller 6 by the set value calculation device 9 (block 47). Thereafter, as shown in FIG. 2, during the period (period c) in which the rear end of the plate (and the front end of the next plate) passes through the heating furnace (period c), the furnace temperature, the nozzle pressure, and the passage speed in the furnace are changed. The temperature TF2, the nozzle pressure P2, and the furnace speed LS2 are obtained.

FIG. 5 is a graph showing the relationship between the passage speed in the furnace and the nozzle pressure, with the vertical axis representing the passage speed in the furnace and the horizontal axis representing the nozzle pressure. However, in FIG.
4 shows the relationship between the passage speed in the furnace and the nozzle pressure at the furnace temperature TF1, and the solid line 25 shows the relationship between the passage speed in the furnace and the nozzle pressure at the furnace temperature TF2. As shown in FIG. 5, in the present embodiment, the in-furnace velocity LS
2 and the nozzle pressure P2 (△) are determined by comparing the in-furnace speed LS1 and the nozzle pressure P1 at the start point and end point of the plate material intermediate portion.
Lower than (○). When the furnace temperature reaches the maximum value (furnace temperature TF1), the sheet passing speed in the furnace also reaches the maximum value (in-furnace speed LS1 '(●)).

As described above, when the annealing furnace is controlled by the control method according to the present embodiment, the temperature inside the heating furnace is raised to the maximum furnace capacity when the intermediate portion of the plate material passes through the inside of the heating furnace. The nozzle pressure and the passage speed in the furnace are changed in accordance with the actual measured value of the furnace temperature at this time. Even when the temperature is raised, the sheet temperature during annealing can be maintained at a constant value (sheet temperature TM). Therefore, even when the capacity of the accumulator is low, the productivity can be improved as compared with the case where the sheet material is annealed by the conventional continuous annealing furnace.

[0037]

EXAMPLES Hereinafter, test results of continuous annealing of a sheet material using the control method of the continuous annealing furnace according to the embodiment of the present invention will be specifically described in comparison with test results of comparative examples.

First, a payout reel on which an aluminum alloy plate having a thickness of 0.6 mm is wound is prepared, and this aluminum alloy plate is annealed by the method shown in FIGS. 1 to 5 and the control method shown in FIGS. did. That is, in the embodiment, the furnace temperature and the furnace passage speed when the middle portion of the aluminum alloy plate passes through the heating furnace, the furnace temperature and the furnace when the front and rear ends of the aluminum alloy plate pass through the heating furnace, It is higher than the internal passing speed. On the other hand, in the comparative example, the furnace temperature was kept constant. The temperature of the aluminum alloy plate in the heating furnace was 420 ° C., and the length of the intermediate portion of the aluminum alloy plate in the longitudinal direction was 3000 m.

As described above, the aluminum alloy sheet was continuously annealed by the two methods, the time required for annealing the intermediate portion of the aluminum alloy sheet was measured, and the annealing efficiency was calculated. The annealing efficiency is obtained by calculating the production efficiency in the example when the production efficiency in the comparative example is set to 100. The annealing conditions and evaluation results are shown in Table 1 below.

[0040]

[Table 1]

As shown in Table 1 above, according to the method shown in FIGS. 1 to 5, the furnace temperature can be raised to 545 ° C. when annealing the intermediate portion of the aluminum alloy plate.
Thereby, the passage speed in the furnace can be increased, so that the annealing efficiency is improved as compared with the comparative example.

[0042]

As described in detail above, according to the present invention,
Since the temperature in the furnace of the heating furnace and the passing speed of the plate material in the furnace are changed in conjunction with each other, the temperature in the furnace when the intermediate portion of the plate material passes can be increased to the temperature at the maximum capacity of the heating furnace, Thereby, productivity can be improved compared with the case where the sheet material is annealed by the conventional continuous annealing furnace.
Further, in the present invention, the pressure of the nozzle can be changed in conjunction with the actual measured value of the temperature in the heating furnace and the passage speed of the plate material in the furnace, so that the nozzle suitable for the furnace temperature and the furnace passage speed is used. Pressure can be set. Thereby, the annealing efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an annealing furnace when a sheet material is continuously annealed by a control method according to an embodiment of the present invention.

FIG. 2 is a timing chart illustrating a method for controlling a continuous annealing furnace according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a part of a method for controlling a continuous annealing furnace according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating a part of a method for controlling a continuous annealing furnace according to an embodiment of the present invention.

FIG. 5 is a graph showing the relationship between the in-furnace passage speed and the nozzle pressure, with the vertical axis representing the passage speed in the furnace and the horizontal axis representing the nozzle pressure.

FIG. 6 is a schematic view showing a conventional continuous annealing furnace.

FIG. 7 is a control timing chart according to a conventional annealing method when the capacity of the accumulator is low.

FIG. 8 is a graph showing the relationship between the in-furnace passage speed and the nozzle pressure, with the vertical axis representing the passage speed in the furnace and the horizontal axis representing the nozzle pressure.

FIG. 9 is a graph showing the relationship between the in-furnace passage speed and the nozzle pressure, with the vertical axis representing the passage speed in the furnace and the horizontal axis representing the nozzle pressure.

FIG. 10 is a graph showing the relationship between the in-furnace passage speed and the nozzle pressure, with the vertical axis representing the passage speed in the furnace and the horizontal axis representing the nozzle pressure.

[Explanation of symbols]

 1; Annealing furnace 2: Plate material 3: Furnace temperature detector 4: Nozzle pressure detector 5; Furnace speed detector 6; Furnace temperature regulator 7; Nozzle pressure regulator 8; Furnace velocity regulator 9; Set value calculation Apparatus 10, 11; Accumulator 12; Outlet speed detector 13; Outer diameter measuring device 14; Payout reel 15; Take-up reel 16;

Claims (5)

[Claims] 1. A plate material discharged from a discharge reel is passed through a heating furnace while adjusting the supply by an inlet accumulator and an outlet accumulator of a heating furnace, and a heating gas is blown from a nozzle to the plate material in the heating furnace. A method for controlling a continuous annealing furnace for heating and annealing the plate material and winding the plate material on a take-up reel, wherein the temperature in the furnace of the heating furnace and the passing speed of the plate material in the furnace are changed in conjunction with each other. Control method of annealing furnace. 2. The control method for a continuous annealing furnace according to claim 1, wherein the pressure of the nozzle is raised and lowered in conjunction with the rise and fall of the furnace temperature and the furnace passage speed. 3. A front-end control for a period required to connect the leading end of the plate to a preceding plate and a rear-end control for a period required to connect a rear end of the plate to a succeeding plate. Is that the in-furnace temperature TF2, the nozzle pressure P2 and the in-furnace passage speed LS2 are constant, and in the control of the intermediate part thereof, the rise time of the in-furnace temperature and the in-furnace passage speed, the in-furnace temperature and the in-furnace The continuous annealing according to claim 1 or 2, wherein the continuous annealing has a period in which the passing speed is constant at TF1 and LS1, respectively, and a falling period in which the furnace temperature and the furnace passing speed decrease to TF2 and LS2, respectively. Furnace control method. 4. After the leading end of the plate material reaches the take-up reel and starts winding, the traveling speed of the plate material on the downstream side in the traveling direction of the plate material from the outlet accumulator and the speed of the plate material in the heating furnace. 4. The control method for a continuous annealing furnace according to claim 3, wherein when the in-furnace passing speed matches, the in-furnace temperature and the in-furnace passing speed are started to increase. 5. A method for estimating the rate of decrease in the temperature of the furnace based on the actually measured value of the rate of increase in the temperature of the furnace, and determining the rate of decrease in the temperature of the furnace from TF1 to TF2 based on the rate of decrease. Estimating the passage length of the plate material in the furnace, and when the passage length in the furnace coincides with the remaining length of the plate material remaining on the payout reel, the descent of the furnace temperature and the furnace passage speed is started. The method for controlling a continuous annealing furnace according to claim 3 or 4, wherein: