JP3345101B2 - Method and apparatus for controlling cold tandem rolling of 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 method and an apparatus for controlling cold tandem rolling of a metal strip having a rolling mill at each of two or more stands, and more particularly to a method for dull finishing at a later stand or a final stand. It is suitable for cold tandem rolling of a thin plate subjected to light reduction rolling such as skin pass.

[0002]

2. Description of the Related Art In cold tandem rolling (hereinafter referred to as dull rolling) using dulled rolls in a final stand, in order to transfer a good dull line to a steel sheet, a change in the rolling load of the final stand is determined by a predetermined value. It is necessary to keep it within an allowable range, and thus there is a limitation on the amount of rolling reduction. Moreover, in this type of dull rolling, since the rolling at the final stand performs rolling with light reduction and high friction, the amount of influence on the backward tension change with respect to the amount of rolling reduction is small,
The tension control at the rear end of the final stand cannot be sufficiently performed only by the amount of rolling operation of the rolling mill of the final stand. Therefore, conventionally, the rear tension control of the last stand is performed by controlling the roll speed of the preceding stand.

On the other hand, as is known, there are various factors for controlling the thickness of the exit side of the rolling mill at each stand. According to the so-called rolling theory, factors such as the amount of reduction, the roll speed, and the front and rear tensions are complicated. Intervene. Under such circumstances, in cold tandem rolling, in which plastic strain accumulates and the plastic coefficient increases as it reaches the later stage, the amount of influence on the change in sheet thickness due to the amount of rolling reduction in the rolling mill in the latter stage stand is particularly small. Generally, the thickness is controlled by controlling the speed, and the inter- and backward tensions are controlled by controlling the amount of reduction.

[0004] Fig. 5 shows an example of control of cold tandem-dal rolling constructed by such a conventional technique. In this tandem rolling mill 1 having four stands of first to fourth stands S1 to S4, the metal strip to be cold-rolled, that is, the strip 20, is passed in the direction of arrow a, and the fourth stand S4 in the figure is It corresponds to a final stand, that is, a stand for performing dull rolling. Looking at the fourth stand S4, the rolling load of the rolling mill of the fourth stand S4 is independently controlled in order to suppress the fluctuation of the rolling load required for the dull rolling. That is, the fourth stand rolling load cell 10
, The rolling load of the fourth stand S4 is detected, and the fourth stand rolling load control device 11 calculates the rolling operation amount in accordance with the detected fourth stand rolling load, and calculates the rolling load control signal corresponding to the operated amount. In response to the rolling load control signal, the fourth stand rolling position control device 12 outputs a drive signal to a fourth stand actuator 18 such as a hydraulic cylinder for controlling each roll position. Is controlled, whereby the fourth stand rolling load control system 23 is constructed. Therefore, in the fourth stand S4, the rolling load is kept within the allowable fluctuation range required for the dull rolling, and an appropriate dull line is transferred to the strip 20.

On the other hand, the rear tension of the fourth stand S4 is controlled by the fourth rear tension control system 22 for controlling the roll speed of the third stand S3 as described above. That is, the tension between the third stand S3 and the fourth stand S4, that is, the fourth stand rear tension is detected by the third stand exit side tension meter 6, and the fourth stand rear tension is detected in accordance with the detected fourth stand rear tension. The stand rear tension control device 7 calculates a roll speed operation amount and outputs a roll speed control signal corresponding to the operation amount, and the third stand roll speed control device 8 controls the roll drive motor in accordance with the roll speed control signal. A drive signal is output, and the number of rotations of the roll drive motor is controlled by the drive signal, whereby the rear tension of the fourth stand is controlled within an allowable range that enables stable operation without breaking or narrowing of the strip 20. You.

The thickness of the exit side plate of the fourth stand S4 is, as described above, the third stand S3, the second stand S2 and / or the second stand S2.
Alternatively, it is controlled by a fourth stand thickness control system 21 that controls the roll speed of the stand on the entrance side. That is,
The measured thickness of the exit side of the fourth stand S4 is detected by the fourth stand exit thickness gauge 2, and the fourth stand thickness control device 3 is operated in accordance with the detected actual thickness of the fourth stand exit side thickness.
Is the roll speed of the third stand S3 and the second stand S2
And / or an operation amount of the roll speed of the stand on the entrance side is calculated and a roll speed control signal corresponding to the operation amount is output. The third stand roll speed control device 8 and the second stand roll speed control device 9 that have been inputted output drive signals to the roll drive motors to be controlled, respectively, and the rotation speed of the roll drive motor is controlled by the drive signals. Thus, the thickness of the fourth stand exit side plate is controlled to a predetermined plate thickness.

The fourth stand rear tension control system 2
The third stand roll speed control signal output from each of the second and fourth stand thickness control systems 21 is added by the adder 31 and then input to the third stand roll speed control device 8.

[0008]

As described above, in the cold tandem rolling control device constructed according to the prior art and the control method therefor, as long as there is no interference of the respective control systems in the dull rolling in the steady state. There is no doubt that stable thickness control, tension control, and rolling load control are possible.

However, in the cold tandem rolling control device and the control method thereof, the third stand roll speed control device 8 includes the control signal of the fourth stand thickness control system 21 via the proportional distributor 4 and the fourth stand thickness control system. Back tension control system 2
2 is added to the third stand S3
Since the roll speed operation amount is given as, for example, when there is an error in the initial setting of the rolling position and the roll speed, or when the rolling state changes due to acceleration or deceleration of the relative passing speed,
The control signals of the amount control systems 22 and 21, ie, the roll speed operation amounts, may interfere with each other, which makes it difficult to achieve both stable fourth stand thickness control and backward tension control.

In addition, in the change of the rolling state caused by the variation of the friction coefficient due to the acceleration / deceleration of the relative passing speed and the variation of the hardness of the strip 20, the reduction ratio (entrance / outlet thickness ratio), tension, tension,
Since it is impossible as a rolling phenomenon to always keep the three rolling loads at a certain reference value, at least in such dull rolling, a thickness gauge 13 installed on the exit side of the third stand was used. Thickness control is not generally performed.

Therefore, in the conventional cold tandem rolling control apparatus and the control method therefor, there is no effective means for avoiding the interference between the thickness control system and the rear tension control system of the final stand as described above, and the rear tandem rolling control system is previously provided. The interference was assumed by setting the control range (dead zone) of the tension control system wide or setting the proportional distribution of the operation amount of the plate thickness control system to a high distribution upstream of the second stand (ie, the second stand). The control system must be set. However, if the control range (dead zone) of the rear tension control system is widened as described above, there is a problem that the response is reduced, so that it is impossible to follow a sudden change in tension, and stable operation is hindered. In addition, in the setting for distributing the operation amount of the thickness control system to the stand two steps before, the control gain cannot be increased sufficiently because the dead time increases, resulting in poor responsiveness and consequently low response. In addition to being an obstacle to improving the thickness control, since the preceding stand does not have its own thickness control system, thickness acceleration is induced when the relative passing speed is accelerated or decelerated, and the thickness accuracy is further deteriorated. There's a problem.

The present invention has been developed in view of these problems, and it is an object of the present invention to perform tension control capable of improving the thickness accuracy and stabilizing the operation by eliminating interference of the operation amount of the roll speed. It is an object of the present invention to provide a method and a device for controlling a cold tandem rolling of a metal strip which can be performed.

[0013]

Means for Solving the Problems The present inventor has made intensive studies in view of the above problems, and as a result, obtained the following knowledge and developed the present invention. That is, since the rear tension control system of the final stand must control the roll speed of the preceding stand for the above-mentioned reason, the plate thickness control system of the final stand does not directly control the roll speed of the preceding stand. The roll speed of the step stand is controlled. In this case, if the thickness control system of the final stand simply controls the roll speed of the two-stage stand, the delay accumulates and the responsiveness decreases as described above, and at the same time the thickness accuracy deteriorates. Provide a plate thickness control system in the front stand, the front stand plate thickness control system controls the roll speed of the pre-second stand according to the deviation between the plate thickness on the exit side of the stand and the plate thickness target value, The thickness control system of the final stand modifies the target thickness of the preceding stand thickness control system in accordance with the deviation between the thickness of the final stand and the target thickness. In this way, the control of the roll speed of the preceding stand does not interfere, and the delay of each control system is not accumulated,
In addition, it has been found that responsiveness is improved because it is not necessary to increase the control range (dead zone), and that it is possible to respond to changes in the rolling state with high accuracy. Needless to say, by performing independent rolling reduction control on the final stand, it is possible to suppress the rolling load of the stand within an allowable range and transfer a good dull pattern. In addition, the plate thickness control system of the preceding stage stand may perform the pressure reduction control of its own stand so that the plate thickness at the stand exit side may be set to a target value. It is not necessary to perform the roll speed control. Further, the thickness of the outlet side of each stand may be directly detected and obtained by actual measurement, or may be obtained by calculation according to a mass flow law or the like. Here, the present invention generalizes the final stand to the N-th stand, the previous stand to the (N-1) th stand, and the second-last stand to the (N-2) -th stand. Without limitation, the invention is completed as being applied to all cases of light reduction rolling such as skin pass.

Thus, the method for controlling cold tandem rolling of a metal strip according to the present invention is characterized in that a plurality of stands up to an N-th (N ≧ 3 , N is a natural number) stand have metal strips each having a rolling mill. A cold tandem rolling control method, comprising: an entrance side from an (N-1) -th stand according to a deviation between an exit side thickness of a (N-1) -th stand and a target thickness of an exit side of the stand. Rolling
The roll thickness of the Nth stand is controlled by controlling the roll speed of the machine and correcting the target thickness of the (N-1) th stand according to the thickness of the outlet of the Nth stand.
And the (N-1) th is determined according to the rear tension of the Nth stand.
The rolling speed of the rolling mill in the stand is controlled, and independent control of the rolling mill in the N-th stand is performed. Or the Nth stand (N ≧ 2, N is a natural number)
Of metal strips with rolling mills on multiple stands
A cold tandem rolling control method, comprising:
And the target thickness of the stand.
The rolling load of the (N-1) th stand according to the deviation of
And the thickness of the exit side of the Nth stand
(N-1) By modifying the target thickness of the stand
Controlling the thickness of the exit side of the N-th stand;
Of the (N-1) th stand rolling mill according to the rear tension of
Control the rolling speed at the Nth stand
Control.

Further, according to the cold tandem rolling control apparatus for a metal strip of the present invention, the cold tandem rolling apparatus for a metal strip having rolling mills at a plurality of stands up to an Nth (N ≧ 3, N is a natural number) stand is provided. A rolling control device for detecting or calculating the thickness of the exit side of the (N-1) th stand,
The stand-out side plate thickness detection or calculation device, and the (N−1) -th (N−1) is calculated according to a deviation between the detected or calculated stand-out side plate thickness of the (N−1) -th stand and the target plate thickness of the stand-out side. 2)
(N-1) th stand thickness control device for outputting a roll speed control signal of a stand rolling mill;
In response to the roll speed control signal of the stand rolling mill,
-2) No. (N) controlling the roll speed of the rolling mill of the stand
-2) An (N-1) th stand thickness control system including a stand roll speed control device, and an Nth stand exit side thickness detection or calculated by detecting or calculating the exit thickness of the Nth stand. A calculating device, and a thickness of the exit side of the (N-1) th stand according to a deviation between the detected or calculated thickness of the exit side of the Nth stand and a target thickness of the exit side of the stand. An N-th stand thickness control system including an N-th stand thickness control device that outputs a target value correction signal;
1) An N-th stand rear tension detecting device for detecting an N-th stand rear tension between the stand and the N-th stand;
Nth output of a roll speed control signal of a stand rolling mill
The (N-1) th stand is controlled in response to the roll speed control signal of the stand rear tension control device and the rolling mill of the (N-1) th stand.
No. (N-1) controlling the roll speed of the rolling mill of the stand
An N-th stand rolling tension control system comprising a stand roll speed control device, and an N-th stand rolling load detecting device for detecting a rolling load of a rolling mill of the N-th stand as required; An Nth stand rolling load control device for outputting a rolling load control signal for the Nth stand rolling mill according to the rolling load, and controlling a roll position of the Nth stand rolling mill according to the rolling load control signal. An Nth stand rolling load control system comprising an Nth stand rolling position control device is provided.

[0016]

In the method and apparatus for controlling cold tandem rolling of a metal strip according to the present invention, as described above, the thickness of the outlet side of the (N-1) th stand (hereinafter referred to as the former stand) and the former stand are described. In controlling the rolling mill of the preceding stand or the stand on the incoming side from the preceding stand or the second preceding stand according to the deviation from the target sheet thickness on the exit side, for example, the former stand stand provided as the preceding stand thickness control system is provided. The thickness of the exit side of the preceding stand is detected or calculated by the side thickness detection or calculation device, and the thickness of the preceding stand is determined according to the deviation between this thickness and the target thickness of the exit side of the preceding stand. The control device calculates, for example, the operation amount of the roll speed of the (N-2) -th stand (hereinafter, referred to as a two-stage stand) and outputs a roll speed control signal for the second-stage stand corresponding to the operation amount. And this second stage In response to the tundroll speed control signal, the two-stage stand roll speed control device outputs a drive signal to, for example, a roll drive motor to control the roll speed of the rolling mill and, for example, an Nth stand (hereinafter referred to as a final stand). ) The thickness of the exit side of the final stand is detected or calculated by a thickness detection or calculation device for the exit side of the final stand provided as a thickness control system, and this thickness and the thickness of the exit side of the final stand are obtained. In accordance with the deviation from the target value, the final stand thickness control device calculates the correction amount of the target thickness value on the exit side of the preceding stand and sends a correction signal corresponding to the correction amount, for example, to the preceding stand thickness control. By outputting to the device, the target thickness of the exit side of the preceding stand is corrected, so that the thickness of the entrance side of the final stand (that is, the thickness of the exit side of the preceding stand is the same). ) Is equal to the appropriate target value by the roll speed of the last two-stage stand controlled so that the sheet thickness on the exit side of the final stand becomes the target value. Since the correction is made based on the sheet thickness at the exit side of the final stand, the delay of each sheet thickness control system does not accumulate, the responsiveness is improved, and the change in the rolling state can be quickly and rapidly increased. Respond to accuracy.

On the other hand, the rear tension of the final stand is detected by, for example, a final stand rear tension detecting device provided as the final stand rear tension control system. The operation amount of the roll speed of the rolling mill of the front stand required to make the back tension equal to the predetermined value is calculated, and a roll speed control signal corresponding to the operation amount is output, and according to the roll speed control signal, The front stand roll speed control device outputs a drive signal to, for example, a roll drive motor to control the roll speed of the front stand, thereby controlling the plate speed between the front stand and the final stand, and Since the tension is controlled, it is possible to avoid interference of the roll speed control signal at the preceding stage and to obtain a good final stage. Give the command backward tension to allow for stabilization of operation.

The final stand is controlled by, for example, detecting a rolling load of a rolling mill of the final stand by a final stand rolling load detecting device provided as a final stand rolling load control system, and according to the rolling load. The rolling load control device calculates, for example, a manipulated variable of the rolling load required to suppress the rolling load within the allowable range of the rolling load required for the dull rolling, and outputs a rolling load control signal corresponding to the manipulated variable. Then, the final stand rolling position control device calculates the operation amount of the roll position of the rolling mill of the final stand required to achieve the rolling load control signal, and outputs a control signal corresponding to the operation amount to, for example, a hydraulic cylinder or the like. In this final stand, the rolling load is controlled independently by outputting to the roll position control actuator of As controllable Te, can be suppressed within the allowable range is desired that variation.

[0019]

FIG. 1 shows an embodiment of a method for controlling cold tandem rolling of a metal strip according to the present invention and a cold tandem rolling mill employing the same. In this tandem rolling machine 1 having four stands of the first to fourth stands S1 to S4, the metal strip to be cold-tandem-rolled, that is, the strip 20, is passed in the direction of arrow a in the same manner as in the conventional case. The fourth stand S4 in the drawing corresponds to the final stand, that is, the stand for performing the dull rolling. In the present invention, the fourth stand of this embodiment is the Nth stand, the third stand is the (N-1) th stand, and the second stand is the (N-th) stand.
2) Equivalent to a stand.

The fourth stand S4 includes a fourth stand rolling load control system for independently controlling the rolling load of the rolling mill of the fourth stand S4 in order to suppress a change in the rolling load required for the dull rolling. 23 are provided. This fourth
The stand rolling load control system 23 detects the rolling load of the rolling mill of the fourth stand S4.
And calculating, in accordance with the detected fourth stand rolling load, a rolling reduction amount such that the rolling load is suppressed within the predetermined allowable range, and outputs a rolling load control signal corresponding to the corrected amount. Fourth stand rolling load control device 11
And a fourth stand actuator 1 such as a hydraulic cylinder for controlling each roll position according to the rolling load control signal.
And a fourth stand rolling-down position control device 12 that outputs a drive signal to the roll 8. The roll signal is controlled by the drive signal so that the rolling load is suppressed within the allowable fluctuation range required for the dull rolling. The proper dull eyes are strip 2
Transferred to 0.

Fourth stand S for carrying out stable operation
4th stand back tension control system 2 for controlling back tension of 4
Reference numeral 2 denotes a third stand exit side tensiometer 6 for detecting the tension between the third stand S3 and the fourth stand S4, that is, the fourth stand rear tension, and the detected fourth stand rear tension, Calculating a roll speed operation amount of the rolling mill of the third stand S3 such that the back tension is kept within a predetermined value allowable range, and outputting a third stand roll speed control signal corresponding to the operation amount; A drive signal is output to the stand rear tension control device 7 and the roll drive motor in accordance with the roll speed control signal, and the drive signal is used to control, for example, the number of revolutions of the roll drive motor, thereby controlling the rolling mill of the third stand. And a third stand roll speed control device 8 for controlling the roll speed. The fourth stand rear tension control system 22 controls the fourth stand rear tension within an allowable range that enables stable operation without breaking or narrowing of the strip 20.

On the other hand, a third stand thickness control system 24 for controlling the thickness of the outlet of the third stand S3 newly set in the present invention detects the actual measured value of the thickness of the outlet of the third stand S3. And a second stand-out thickness gauge 2 for measuring the thickness of the third stand and a target thickness of the third stand at the exit side. A third stand thickness control device 14 for calculating a roll speed operation amount of the stand S2 and outputting a second stand roll speed control signal corresponding to the operation amount, and a roll drive motor according to the roll speed control signal. A second stand roll speed control device 9 that outputs a drive signal and controls, for example, the number of revolutions of a roll drive motor by the drive signal to control the roll speed of the rolling mill of the second stand. The third stand thickness control system 24 controls the thickness of the outlet of the third stand so as to match a preset target value.

A fourth stand thickness control system 25 for controlling the thickness of the fourth stand S4 on the exit side is provided with a fourth stand S4.
4th stand outboard thickness gauge 2 for detecting the actual thickness of the outlet side of No. 4 and the detected actual thickness of the fourth stand outlet side and the preset outlet thickness of the fourth stand. In accordance with the deviation from the target value, a correction amount of the target thickness value on the exit side of the third stand, ie, on the entrance side of the fourth stand, is calculated, and a third stand exit side thickness correction signal corresponding to the correction amount is generated. , The third
And a fourth stand thickness control device 15 for outputting to the stand thickness control device 14. The target thickness of the third stand is corrected by the thickness control system 25 of the fourth stand and the roll thickness of the second stand is controlled so as to match the corrected target value. 4th
Since the condition for the exit side plate thickness of the stand to match the target value is satisfied, the fourth stand exit side plate thickness is a stable plate thickness as a product.

The response of product thickness control by the third stand thickness control system 24 and the fourth stand thickness control system 25 will be considered. The time required for the response is the maximum, even if the rolling conditions change at any time, the delay time of the control system itself and the third time.
Stand exit thickness gauge 13 to 4th stand exit thickness gauge 2
Since there is only the time required for the sheet passing, the dead time does not occur when the operation distribution amount to the roll speed of the second-stage stand, that is, the second stand, is increased as in the related art.

Further, since the control signal interference between the fourth stand rear tension control system 22 and the respective plate thickness control systems 24 and 25 does not occur as in the prior art, the rear tension of the fourth stand is stable, so that breakage or breakage can occur. Enables stable operation without narrowing down. On the other hand, since the fourth stand rolling load controller 23 can independently control the rolling load of the fourth stand, it is possible to transfer an excellent dull pattern. Of course, since these tension control system and rolling load control system are independent monitor controls, the responsiveness is good.

Next, the constructions of the fourth stand thickness control device 15 of the fourth stand thickness control system 25 and the third stand thickness control device 14 of the third stand thickness control system will be described with reference to FIG.
This will be described with reference to FIG. Here, in order to generalize the names of the stands, the fourth stand, that is, the last stand is referred to as an Nth stand. Hereinafter, the third stand is referred to as an N-1st stand, and the second stand is referred to as an N-2th stand. Show.

The fourth stand thickness control device 15 is
The fourth stage detected by the fourth stand exit side thickness gauge 2
Stand, ie, Nth stand exit side plate thickness h_NFrom the Nth
Tand exit side target thickness h_N ^refAdder / subtractor 26 for subtracting
And its output, that is, the thickness deviation Δh of the N-th stand exit side._NTo
Accordingly, the correction amount Δh of the target thickness at the exit side of the (N-1) -th stand._{N- 1}
^ref'Is calculated. one
On the other hand, the third stand thickness control device 14
Third stand detected by the stand-out thickness gauge 13
I.e., the thickness of the exit side of the (N-1) th stand h_N-1From the Nth
-1 Stand exit side target thickness h_N-1 ^refSubtraction
The arithmetic unit 28 and its output, that is, the thickness at the exit side of the (N-1) th stand
Deviation Δh_N-1And the above-mentioned N-1 stand outlet side thickness target value modification
Positive Δh_N-1 ^ref'And an adder 29 for adding
Output, that is, the corrected thickness deviation Δh 'on the exit side of the (N-1) th stand
_N-1N-2th stand roll speed operation amount ΔVR according to
_N-2And a proportional integrator 30 for calculating. In addition,
The calculation of the roll speed operation amount by the proportional integrator 30 is as follows.
According to a preset calculation formula based on rolling theory and empirical rules,
Done.

Next, the fourth stand thickness control system 25
Fourth stand thickness control device 15 and third stand thickness
About the operation of the third stand thickness control device 14 of the control system
This will be described with reference to FIGS. Normally, the (N-1) th
Stand out side stand thickness h_N-1Has initial rolling schedule
Target thickness h set in_N-1 ^refSo that
That is, the thickness deviation Δh of the exit side of the (N-1) -th stand of both._N-1Is low
The roll speed control of the N-2nd stand is performed so that the
Will be On the other hand, for example, the Nth stand exit side plate thickness h_NIs the
Nth stand exit side thickness target value h_N ^refAnd that it came off
The thickness deviation Δh_NN-1 stand exit side according to
Target thickness correction amount Δh_N-1 ^ref'Is calculated and this goal
Value correction amount is the thickness deviation Δh of the N-1st stand._N-1
Out of the N-1st stand
Side correction thickness deviation Δh '_N-1N-2 so that
Roll speed control of the stand is performed. At this time,
For example, as shown in FIG._NIs thicker
Standard value h_N ^refIf it becomes too thick, the deviation Δ
h_NN-1 stand exit side calculated so that becomes zero
Target thickness correction amount Δh _N-1 ^ref'Comes out of the N-1st stand
Side plate thickness deviation Δh_N-1And corrected thickness deviation Δ
h '_N-1N-2 stand calculated so that becomes zero
Roll speed operation amount ΔVR_N-2Is output. This
Stand-out side thickness Δh of N-1st stand_N-1Is the target thickness correction value
Initial target value Δh by minute Δh_N-1 ^refIt will be thinner,
As a result, the Nth stand exit side plate thickness h_NIs the target thickness h_N
^refBecomes

FIG. 4 shows the effect of controlling the thickness of the present embodiment and the conventional example. In this figure, the conventional example is described as before the improvement, and the present embodiment is described as after the improvement. In FIG. 3A, the occurrence rate of the off gauge (out of thickness) of ± 1% or more with respect to the target thickness is shown in FIG. FIG. B shows the occurrence rate of the off gauge of ± 5% or more with respect to the target thickness. As can be seen from the figure, at each off-gauge factor, the method and the apparatus for controlling cold tandem rolling of a metal strip according to the present embodiment are significantly improved as compared with the conventional method and apparatus for controlling cold tandem rolling. It has an effect and achieves a thickness control effect equivalent to the off-gauge generation rate of bright rolling used as a reference.

The method and apparatus for controlling the cold tandem rolling of a metal strip according to the present embodiment are the same as those of the prior art shown in FIG.
It can be understood that all the distributions are set to 00% and the thickness control system of the preceding stand is included as a minor loop in the loop. Further, in the above embodiment, the thickness control system is set to monitor control from each thickness gauge. However, if feedback control is performed using the mass flow thickness just under each stand calculated based on the mass flow law, higher response can be obtained. It is also possible to perform control in combination with both.

In addition, the method and apparatus for controlling cold tandem rolling of a metal strip according to the present invention reduce fluctuations in sheet thickness and front / rear tension, so that fluctuations in the rolling load of the final stand are within an allowable range without control. , The final stand rolling load control system can be omitted.
Further, in the above embodiment, the roll speed control of the second pre-stand is performed by the front stand thickness control system in accordance with the deviation between the front stand exit side sheet thickness and the target value, and the last stand thickness control system is used. The correction of the side plate thickness target value is performed. However, according to the cold tandem rolling control method of the metal strip of the present invention, for example, as shown by a broken line in FIG. It is also possible to control the rolling load of the former stand according to the deviation from the target value and the target value, and correct the target value of the sheet thickness on the exit side of the former stand by the final stand thickness control system. It also enables high response and high precision thickness control and front / rear tension control even in a two-stand cold tandem rolling mill.

Further, in the above embodiment, only the cold tandem rolling apparatus for performing the dull rolling at the final stand has been described in detail. However, it is needless to say that the present invention can be widely applied particularly to the apparatus for performing the finish rolling such as the skin pass at the final stand. No.

[0033]

As described above, according to the method and apparatus for controlling cold tandem rolling of a metal strip according to the present invention, the target thickness of the preceding stand thickness control system is obtained by the output of the final stand thickness control system. The final stand exit side sheet thickness is maintained at the target value by correcting the above, and only the output of the final stand tension control system performs the roll speed operation of the preceding stand, thereby preventing the interference of the roll speed operation with the sheet thickness control system. In order to avoid this and keep the final stand rear tension constant and to control the rolling load of the stand within the allowable range by the final stand rolling load control system, it is possible to quickly and accurately perform rapid changes in the rolling state. In addition to stabilizing the product thickness in response to the above, stable operation is possible.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a method for controlling cold tandem rolling of a metal strip and a cold tandem rolling machine using the same according to the present invention.

FIG. 2 shows a fourth stand thickness control device shown in FIG.
It is a schematic block diagram which shows the structure of a stand thickness control device.

FIG. 3 is an explanatory diagram showing time-dependent characteristics of sheet thickness control by the cold tandem rolling mill of FIGS. 1 and 2;

FIG. 4 is an explanatory diagram showing the effect of controlling the thickness of a sheet by the cold tandem rolling mill shown in FIGS. 1 and 2;

FIG. 5 is a schematic configuration diagram illustrating an example of a conventional cold tandem rolling mill.

[Explanation of symbols]

 1 is a cold tandem rolling machine S2 is a second stand S3 is a third stand S4 is a fourth stand 6 is a third stand exit side tensiometer 7 is a fourth stand rear tension controller 8 is a third stand roll speed controller 9 Is the second stand roll speed control device 10 is the fourth stand rolling load meter 11 is the fourth stand rolling load control device 12 is the fourth stand rolling position control device 13 is the third stand exit side thickness gauge 14 is the third stand thickness Control device 15 is a fourth stand thickness control device 16 is a second stand actuator 17 is a third stand actuator 18 is a fourth stand actuator 19 is a fourth stand roll speed control device 20 is a strip 22 is a fourth stand rear tension control system 23 is a fourth stand rolling load control system 24 is a third stand thickness control system 25 is a fourth stand thickness control system Control system 26 is an adder / subtracter 27 is a proportional integrator 28 is an adder / subtractor 29 is an adder 30 is a proportional integrator

Claims (4)

(57) [Claims] 1. A cold tandem rolling control method for a metal strip having a rolling mill in each of a plurality of stands up to an Nth (N ≧ 3 , N is a natural number) stand, wherein the (N-1) th stand The rolling mill on the entrance side from the (N-1) th stand in accordance with the deviation between the exit side sheet thickness of the stand and the exit side sheet thickness target value of the stand.
Control of the roll thickness of the Nth stand by controlling the roll speed of the Nth stand and correcting the target thickness of the (N-1) th stand by the plate thickness of the Nth stand.
And the (N-1) th is determined according to the rear tension of the Nth stand.
A method for controlling cold tandem rolling of a metal strip , comprising controlling a rolling speed of a rolling mill on a stand and independently controlling a rolling mill on an Nth stand. 2. A cold tandem rolling control apparatus for a metal strip having a plurality of stands up to an N-th (N ≧ 3, N is a natural number) stand, wherein: The (N-1) th which is obtained by detecting or calculating the sheet thickness on the delivery side.
The stand-out side plate thickness detection or calculation device, and the (N−1) -th (N−1) is calculated according to a deviation between the detected or calculated stand-out side plate thickness of the (N−1) -th stand and the target plate thickness of the stand-out side. 2)
(N-1) th stand thickness control device for outputting a roll speed control signal of a stand rolling mill;
In response to the roll speed control signal of the stand rolling mill,
-2) No. (N) controlling the roll speed of the rolling mill of the stand
-2) An (N-1) th stand thickness control system including a stand roll speed control device, and an Nth stand exit side thickness detection or calculated by detecting or calculating the exit thickness of the Nth stand. A calculating device, and a thickness of the exit side of the (N-1) th stand according to a deviation between the detected or calculated thickness of the exit side of the Nth stand and a target thickness of the exit side of the stand. An N-th stand thickness control system including an N-th stand thickness control device that outputs a target value correction signal;
1) An N-th stand rear tension detecting device for detecting an N-th stand rear tension between the stand and the N-th stand;
Nth output of a roll speed control signal of a stand rolling mill
The (N-1) th stand is controlled in response to the roll speed control signal of the stand rear tension control device and the rolling mill of the (N-1) th stand.
No. (N-1) controlling the roll speed of the rolling mill of the stand
An Nth stand rear tension control system comprising a stand roll speed control device and a cold roll tandem rolling control device for a metal strip. 3. An Nth stand rolling load detecting device for detecting a rolling load of the Nth stand rolling mill, and outputting a rolling load control signal of the Nth stand rolling mill according to the detected rolling load. N-th stand rolling load control system comprising an N-th stand rolling load control device for controlling a rolling position of a rolling mill of the N-th stand according to the rolling load control signal. The cold tandem rolling control apparatus for a metal strip according to claim 2, comprising: 4. An Nth stand (N ≧ 2, N is a natural number)
Of metal strips with rolling mills on multiple stands
A cold tandem rolling control method, comprising:
And the target thickness of the stand.
The rolling load of the (N-1) th stand according to the deviation of
And the thickness of the exit side of the Nth stand
(N-1) By modifying the target thickness of the stand
Controlling the thickness of the exit side of the N-th stand;
Of the (N-1) th stand rolling mill according to the rear tension of
Control the rolling speed at the Nth stand
Cold tandem rolling of a metal strip characterized by controlling
Control method.