JPH0768319A - Method for controlling tension leveler - Google Patents

Abstract

PURPOSE:To execute stable operation by controlling the elongation percentage of a tension leveler while executing constant tension control in a skin pass mill. CONSTITUTION:At the time of executing shape correction of a strip 2 by passing the strip through a bridle roll 1 on the inlet side, skin pass mill 2, tension leveler 4 and bridle roll 5 on the outlet side, the rotational speeds of the bridle rolls 1, 5 on the inlet and outlet sides and the rotational speed of a tension sensor 17 which is arranged between the mill 3 and the leveler 4 are individually detected with pulse generators 18, 19, 20, their pulse signals are inputted to an individual elongation computing element 24a and mill elongation percentage epsilonM and leveler elongation percentage epsilonL are individually calculated. The calculated results are inputted into an intermesh correction value computing element 24b and, when the leveler elongation percentage epsilonL exceeds the set ceiling value under the state that the mill elongation percentage epsilonM is within a set range, intermesh is decreased and, when the elongation percentage epsilonL exceeds the set lower limit value, intermesh is increased and abnormal elongation of the tension leveler is rapidly eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension leveler control method for correcting the shape of a strip made of rolled cold-rolled steel sheet or the like.

[0002]

2. Description of the Related Art Generally, when the strip shape which is passed through a skin pass mill is supplied to a tension leveler to correct the shape of the strip, both the reduction amount of the skin pass mill and the intermesh amount of the tension leveler are automatically controlled simultaneously. Since it is difficult to do so, (1) a constant pressure / constant tension control method that keeps the load of the skin pass mill constant, and also controls the front-back tension of the skin pass mill to fix the intermesh amount of the tension leveler, (2) skin pass mill Of the skin pass mill, the tension on the skin pass mill entrance side is controlled by the reduction amount of the skin pass mill, the exit side tension of the skin pass mill is controlled by the skin pass mill motor, and the intermesh amount of the tension leveler is fixed and stretched. Constant pressure / elongation rate control that controls total elongation by controlling the elongation rate of the rate motor Method (3) An extension tension control method in which the total elongation is controlled by the reduction amount of the skin pass mill, the tension on the skin pass mill entrance side is controlled by the elongation rate motor, and the tension on the skin path mill exit side is controlled by the skin pass mill motor. One of the two control methods is adopted.

However, in each of the above control methods, there is an unsolved problem that the control becomes unstable when the elongation level is suddenly changed by the tension leveler due to the variation of the plate thickness or the variation of the hardness of the material. In order to solve this unsolved problem, Japanese Unexamined Patent Publication No. 61-20621 (hereinafter referred to as the first conventional example) and Japanese Unexamined Patent Publication No. 2-179320 (hereinafter referred to as the second
A method of controlling the tension leveler described in the conventional example) has been proposed.

That is, in the first conventional example, the entrance-side bridle roll and the exit-side bridle roll are arranged before and after the tension leveler, and the total elongation is increased by giving a peripheral speed difference to the entrance-side bridle roll and the exit-side bridle roll. Rate motor controls the rotation speed of the entrance side bridle roll, and the shape detector detects the strip shape on the exit side of the exit side bridle roll and feeds back this shape detection value to the tension leveler control system and the elongation rate control system. As a result, both the amount of the intermesh of the tension leveler and the elongation rate of the strip are controlled to perform good shape control.

In the second conventional example, when the strip is supplied to the tension leveler through a skin pass mill to correct the shape, the total elongation is controlled by an elongation rate motor, and the tension before and after the skin pass mill is adjusted. The elongation rate of the mill section is controlled by the amount of reduction of the skin pass mill, and when the tension on the entry side of the skin pass mill exceeds the set upper limit value, the intermesh amount of the tension leveler is reduced to By increasing the intermesh amount of the tension leveler when the side tension becomes equal to or lower than the set lower limit value, it is possible to easily balance the inlet and outlet side tensions of the skin pass mill and to control the elongation rate of the skin pass mill part to be constant. Stable operation of the skin pass mill, and fully exerting the shape correction effect unique to the mill So as to obtain the effect.

[0006]

However, in the above-mentioned first conventional example, the strip shape on the outlet side of the outlet bridle roll is detected, and this is used to control the elongation motor control system and the tension leveler control system. It is said that it is possible to perform high-precision shape correction in response to changes in strip properties, but depending on the shape of the outlet strip of the outlet bridle roll, how the intermesh and shift amount are changed. However, it is not disclosed how to correct the elongation rate, and there is an unsolved problem that high-precision shape correction cannot be performed unless it is accurately elucidated in which part the elongation affects the final shape. .

In the second conventional example, the intermesh amount of the tension leveler is decreased when the entrance side tension of the skin pass mill is equal to or higher than the set upper limit value, and the intermesh amount is decreased when the input tension is equal to or lower than the set lower limit value. Since it is controlled so that the input tension becomes the set tension by increasing, the tension constant control with the skin pass mill can be performed, but the elongation rate with the tension leveler cannot be controlled, There is an unsolved problem that the total elongation control is affected.

Therefore, the present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example, and while controlling the tension constant in the skin pass mill, controlling the elongation rate in the tension leveler for stable operation. The purpose is to provide a tension leveler control method that can be performed.

[0009]

In order to achieve the above object, a method of controlling a tension leveler according to the present invention is a method of controlling a tension leveler in which a strip that has passed through a skin pass mill is supplied. Rate and the elongation rate of the tension leveler are individually monitored, and when the elongation rate of the skin pass mill is within the setting range and the elongation rate of the tension leveler exceeds the set upper limit value, the intermesh is reduced and the tension leveler The feature is that the intermesh is increased when the elongation rate exceeds the set lower limit value.

[0010]

In the present invention, the elongation rate of the strip in the skin pass mill and the elongation rate in the tension leveler are individually monitored, and the elongation rate of the tension leveler is set when the elongation rate of the skin pass mill is within the set range. When the upper limit is exceeded, the intermesh of the tension leveler is decreased to decrease the elongation rate of the tension leveler, and when the elongation level of the tension leveler exceeds the set lower limit value, the intermesh of the tension leveler is increased to increase the tension. By increasing the elongation rate in the leveler, the elongation rate in the tension leveler is controlled within a set range, and when abnormal elongation occurs in the tension leveler, it returns to the normal state with high responsiveness.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing an embodiment in which the present invention is applied to constant pressure / elongation rate control in which the elongation rate is controlled by an elongation rate motor under a constant skin pass mill load. In the figure, 1 is
An entrance-side bridle roll, for example, a strip 2 hot-rolled by the entrance-side bridle roll 1 is conveyed to a skin pass mill 3, and the strip 2 temper-rolled by the skin pass mill 3 is straightened by a tension leveler 4. Then, the bridle roll 5 on the outgoing side conveys the film to a winding device (not shown).

Here, the entrance-side bridle roll 1 and the exit-side bridle roll 5 are mechanically connected via a differential gear 7 composed of a planetary gear whose gear ratio can be adjusted by an elongation motor 6. By rotating the output-side bridle roll 5 with the drive motor 8, the input-side and output-side bridle rolls 1 and 5 corresponding to the gear ratio of the differential gear 7 are driven.
The total elongation of the strip is controlled according to the difference in peripheral speed.

The skin pass mill 3 has a strip 2
A backup roll 3B rollingly contacting the work roll 3W for rolling is connected to the skin pass mill motor 9, and by rotating this skin pass mill motor 9, the skin pass mill exit side tension is adjusted and the lower backup roll 3B By controlling the pressure of the hydraulic cylinder 10 that controls the reduction amount, the skin pass mill entrance side tension is adjusted.

Further, in the tension leveler 4, the inter-mesh amount represented by the pushing amount of the work roll 4W with respect to the deflector roll 4D is adjusted by the inter-mesh adjusting motor 11. Then, the elongation ratio motor 6, the drive motor 8, the skin pass mill motor 9, the hydraulic cylinder 10, and the intermesh adjustment motor 11 are controlled by the control device 15. The controller 15 controls tension sensors 16 and 17 for rolling the strip 2 on the inlet side and the outlet side of the skin pass mill 3 to detect the tension, and the rotation speeds of the inlet bridle roll 1 and the outlet bridle roll 5. Pulse generators 18 and 19 for generating a pulse
And each detection signal of the pulse generator 20 that generates a pulse according to the rotation speed of the tension sensor 17, and the total elongation rate setting device 30 that sets the total elongation rate setting value ε _TS, and the reduction of the skin pass mill 3. A pressure setter 31 that sets a pressure set value P _S that determines the amount, an intermesh setter 32 that sets an intermesh set value IM _S of the tension leveler 4, an exit side bridle roll 5
Speed reference setter 33 for setting the speed reference value V _S for
Are connected to each other, and based on these, the total elongation control unit 21 that controls the total elongation of the elongation motor 7 and the amount of reduction of the skin pass mill 3 are controlled to control the inlet side tension of the skin pass mill 3. The mill entrance tension controller 22, the mill exit tension controller 23 that controls the exit tension of the skin pass mill 3 by controlling the rotation speed of the skin pass mill motor 9, and the tension leveler 4.
Of the tension leveler 4 by controlling the inter-mesh amount of the tension leveler 4, and a rotation speed control unit 2 of controlling the rotation speed of the exit side bridle roll 5.
5 and.

Here, the total elongation control unit 21 receives pulse signals output from the pulse generators 18 and 19 according to the rotation speeds of the entrance and exit bridle rolls 1 and 5, and calculates based on these. From the rotational speed difference, the entrance bridle roll 1 and exit bridle roll 5
And total elongation calculator 21a for calculating a total elongation epsilon _T of the strip 2 between, calculation for calculating the deviation between the total elongation epsilon _T and total elongation set value epsilon _S of the total elongation calculator 21a Unit 21b and this calculator 2
An elongation rate controller 21c that calculates the total elongation rate control amount based on the output of 1b, and a speed reference control amount calculation that calculates the speed reference control amount based on the speed reference value V _S and the total elongation rate set value ε _TS. 21d, an adder 21e for adding the speed reference control amount of the speed reference control calculator 21d and the total elongation control amount of the elongation ratio controller 21c, and an expansion rate based on the addition output of the adder 21e. An automatic speed controller 21f for driving and controlling the motor 7 is provided.

The mill entrance side tension controller 22 controls the mill entrance side tension.
Mill-side tension detection value T of sensor 16 _MIDAnd preset
Till mill entry side tension set value T_MISA calculator that calculates the deviation from
22a and the tension deviation from this calculator 22a are input.
And the tension control correction value ΔP corresponding to this_TITo output automatic
The tension controller 22b and the automatic tension controller 22b
Forced tension control correction value ΔP_TIAnd pressure set value P_SBias with
The tension leveler growth rate system that will be described later while calculating the difference
Pressure correction value P supplied from controller 24_AOperation to add
Based on the calculation result of the calculator 22c and the calculator 22c.
The pressure that controls the pressure of the hydraulic cylinder 10 of the Kinpass mill 3.
And a force controller 22d.

The mill exit side tension control unit 23 controls the mill exit side tension.
Mill exit side tension detection value T of sensor 17 _MODAnd preset
Tail mill exit side tension set value T_MOSA calculator that calculates the deviation from
23a and the tension deviation from the calculator 23a are input.
Then, the speed correction value V corresponding to this_AAutomatic tension control to output
Control device 23b and speed correction value of this automatic tension controller 23b
V_AAnd speed reference set value V_SCalculator 2 that calculates the deviation from
3c and the deviation output from the calculator 23c
Speed control for driving and controlling the skin pass mill motor 9
23d.

The leveler expansion rate control unit 24 outputs pulse signals C _PI, C according to the rotational speeds of the input-side and output-side bridle rolls 1, 5 output from the pulse generators 18, 19.
_{When PO} is input, a pulse signal C _PC corresponding to the rotation speed of the mill exit side tension sensor 17 output from the pulse generator 20 is also input, and the skin pass mill 3 based on the pulse signal C _PI and the pulse signal C _PC. while calculating the elongation epsilon _M of the individual elongation calculator 24a for calculating a percent elongation epsilon _L of the tension leveler 4 on the basis of the pulse signal C _PC and the pulse signal C _PO, in this individual elongation calculator 24a An intermesh correction value calculator 24b that calculates the intermesh correction value of the tension leveler 4 by performing the calculation of FIG. 2 described later based on the calculated skin path elongation rate ε _M and the tension leveler elongation rate ε _L , and this intermesh An adder 24 for adding the correction value IM _A calculated by the correction value calculator 24b and the intermesh amount setting value IM _S
c and an automatic position controller 24d that controls the position of the intermesh adjusting motor 11 based on the added output of the adder 24c.

Here, the intermesh correction value calculator 2
4b is composed of, for example, a microcomputer, and is shown in FIG.
The intermesh control process shown in is executed. The intermeshing control processing, first in step S1, reads the skin pass elongation epsilon _M from the individual elongation calculator 24a, and then proceeds to step S2, preset the skin pass elongation epsilon _M read in Step S1 The absolute value of the deviation from the set skin path elongation rate set value ε _MS | ε _M −ε _MS | is calculated.

Next, in step S3, the absolute value is
│ε_M−ε_MS｜ is the preset skin pass mill elongation percentage
It is determined whether or not the value is within α. This decision is
Mpus mill elongation ε_MWhether or not is within the setting range
That is_M−ε _MSWhen │> α,
Skin pass mill elongation ε_MIs outside the setting range.
Disconnection, the process proceeds to step S4, and the mill entrance side tension control unit 22
Pressure correction value P for the calculator 22c of_AAnd perform
Calculated pressure correction value P_AAfter sending to the computing unit 22c
Return to step S1, | ε_M−ε_MSWhen | ≦ α
Is the skin pass mill elongation ε_MIs within the setting range
For intermesh control after step S5
Transition.

In step S5, the individual elongation rate calculator 24
Tension leveler elongation ε calculated in a_LRead
Then, the process proceeds to step S6 to increase the tension leveler.
Rate ε _LAnd preset tension leveler growth rate setting value
ε_LSAbsolute value of deviation from |_L−ε_LS| Is calculated. Next
Then, the process proceeds to step S7 and the absolute value | ε_L−ε_LS|
Within the preset tension leveler allowable elongation β
Or not. This judgment is based on the tension leveler
Rate ε_LIs to determine whether is within the setting range.
, | Ε_L−ε_LSWhen | ≦ β, the tension level is
Bella growth rate ε_LIs within the setting range and the current
If it is determined that the amount of compression is appropriate, the above step S1
Return to ｜ ε_T−ε_TSWhen |> β, tension
If it is judged that abnormal growth has occurred in
Go to step S8.

In step S8, the tension leveler is
Elongation rate ε_LIs the tension leveler growth rate setting value ε_LSGreater than
Whether or not_L> Ε_LSWhen the
Up S9, the current intermesh correction value I
M_AThe value obtained by subtracting the decrease correction value ΔIM (IM
_A−ΔIM) is the new intermesh correction value IM_AWhen
And store the update, and then move to step S10 to update.
Intermesh correction value IM_ATo the adder 24c
To step S1 and output ε_L<Ε _LSIs
Occasionally, the process moves to step S11 and the current interface
Mesh correction value IM_AIncrease correction value ΔIM
The added value (IM_A+ ΔIM) is a new intermesh
Correction value IM_AUpdate and store as, then step
The intermesh correction value I updated by shifting to S10
M_ATo the adder 24c and then return to step S1
It

The rotation speed control unit 25 controls the speed reference set value V
_SThe automatic speed that controls the rotation speed of the drive motor 8 based on
A degree controller 25a is provided. Next, the operation of the above embodiment
Will be explained. Now strip 2 is the entrance bridle roll
1 is passed through the skin pass mill 3 and
Shaped with tension leveler 4 after temper rolling with smill 3
The device is straightened and wound by the bridle roll 5 on the exit side.
Have been transported to. In this state, the strip
Speed reference value V according to the property of_SIs the speed reference setter 33
This speed reference value V_SIs the rotation speed control unit 25
Since this is input to the automatic speed controller 25a of
Speed controller 25a for speed reference value V_SDrive motor 8 according to
Drive the rotating bridle roll 5 directly to drive it.
It moves and the bridle low on the entry side via the differential gear 7.
The tool 1 is rotationally driven with a predetermined rotational speed difference. This and
Set the total elongation rate according to the properties of strip 2
Value ε_TSIs set by the elongation rate setting device 30, and this is the total
By inputting to the elongation control section 21, this total
Total elongation rate calculator 21 in the elongation rate control unit 21
a, the entrance side detected by the pulse generators 18 and 19
And strike from the rotational speed difference between the exit side bridle rolls 1 and 5.
Total elongation of Lip 2 ε_TAnd the calculation unit 21b
Total elongation ε_TAnd total elongation set value ε_TSWith
The deviation is calculated, and this is adjusted by the elongation rate controller 21c according to the deviation.
Speed correction value V_ASAnd the speed reference calculator 2
Speed reference value V in 1d_SAnd total elongation set value ε_TSAnd to
Based on the total elongation set value ε_TSSatisfy the speed standard
Command value V_CSAnd the speed reference command value V_CSAnd speed supplement
Positive value V_ASIs added by the adder 21e and the speed is automatically controlled.
This automatic speed controller 2 is output by outputting it to the controller 21f.
The rotational drive of the elongation rate motor 6 is controlled by 1f to control the differential gear.
By controlling 7
Control the rotation speed of the entrance side bridle roll 1.
Total elongation ε calculated from measured values_TIs the total growth
Rate setting value ε _TSTo be matched.

In this way, in the state in which the inlet and outlet bridle rolls 1 and 5 are rotationally controlled by the rotational speed control unit 25 and the total elongation control unit 21, the mill inlet side tension control unit 22 has a computing unit. At 22a, the deviation between the mill entry side tension detection value T _MID output from the tension sensor 16 and the preset mill entry side tension set value T _MIS is calculated, and the calculation result is supplied to the automatic tension controller 22b. By
The automatic tension controller 22b outputs a pressure correction value P _TI according to the tension deviation to the calculator 22c.
Is added to the preset mill pressure setting value P _S and the added value is supplied to the pressure controller 22d, whereby the hydraulic pressure of the hydraulic cylinder 10 of the skin pass mill 3 is controlled by the pressure controller 22d. At this time, skin pass mill 3
When the inlet side tension detection value T _{MID of} is smaller than the mill inlet side tension set value T _MIS , the deviation output from the calculator 22a becomes a positive value, so the calculation result of the calculator 22c is the pressure set value P _The value becomes smaller than _S , and accordingly, the pressure of the hydraulic cylinder 10 is reduced, and the amount of reduction of the work roll 3W with respect to the strip 2 is reduced, whereby the mill entry side tension is increased, and the mill entry side tension set value. Matched with T _MIS . Conversely, when the mill entry side tension detection value T _MID is larger than the mill entry side tension set value T _MIS , the calculator 22a
Since the deviation output from is a negative value, the calculator 22c
The calculation result in is a value larger than the pressure setting value P _S ,
In response to this, the pressure of the hydraulic cylinder 10 is increased and the amount of reduction of the work roll 3W with respect to the strip 2 is increased, whereby the mill entrance side tension is decreased and becomes equal to the mill entrance side tension set value T _MIS. Controlled by.

As described above, when the mill entrance side tension control section 22 adjusts the mill entrance side tension by adjusting the amount of reduction of the skin pass mill 3, the mill exit side tension also changes accordingly. , When the mill exit side tension detection value T _MOD of the mill exit side tension sensor 17 is smaller than the mill entrance side tension set value T _MOS , the deviation output from the calculator 23a becomes a positive value. The calculation result becomes a value smaller than the speed reference value V _S, and the rotation speed of the skin pass mill motor 9 is reduced accordingly, and the work roll 3
The peripheral velocity of W is decreased, and thereby the mill exit side tension is increased to match the mill exit side tension set value T _MOS . Conversely, the mill exit side tension detection value T _MOD is equal to the mill exit side tension set value T
When it is larger than _{MOS, the} deviation output from the calculator 23a becomes a negative value, and therefore the calculation result in the calculator 23c becomes a value larger than the speed reference value V _S, and the rotation of the skin pass mill motor 9 is accordingly increased. The speed is increased and the peripheral speed of the work roll 3W is increased, whereby the mill exit side tension is reduced and controlled to be equal to the mill exit side tension set value T _MOS .

In this way, the strip tension on the inlet side and the outlet side of the skin pass mill 3 is controlled so as to match the set value. On the other hand, in the leveler expansion rate control unit 24, the individual expansion rate calculator 24a uses the individual pulse generators 18,
The transport speed of the strip 2 at each position is calculated based on the pulse signals of 19 and 20, and the skin pass mill elongation rate ε _M at the skin pass mill 3 and the tension leveler elongation rate ε _L at the tension leveler 4 are calculated from these speed differences. Is calculated individually. Then, the intermesh correction value calculator 24b performs the intermesh control processing of FIG. 2 based on the calculated skin pass mill elongation ε _M and tension leveler elongation ε _L. That is, the mill elongation rate ε _M of the skin pass mill 3 is the preset skin path mill elongation rate ε _MS
It is determined whether or not it is within the allowable range in which the set value α is added or subtracted. If it is outside the allowable range, the process proceeds to step S4, and the calculator 22c of the mill entrance side tension control unit 22
_A pressure correction value P _A that is positive when ε _M > ε _MS and negative when ε _M <ε _MS is calculated so that the skin pass mill elongation ε _M matches the set value ε _MS , and this is calculated. Calculator 22c
To control the amount of reduction of the skin pass mill 3 to control the skin pass mill elongation rate ε _M within an allowable range.

Then, the skin pass mill elongation ε_MIs acceptable
When it is within the range (| ε_M−ε _MS| ≦ α), Tensile
Growth rate of yonverera 4 ε_LWhether is within the allowable range
If it is within the allowable range, the process returns to step S1.
The tension leveler is out of the allowable range.
Rate ε_LIs the set value ε_LSIt is determined whether or not the
Up S8), ε_L> Ε_LSTension level when
La elongation rate ε_LIs too large, step S
9 and the current intermesh correction value IM_AOr
The value obtained by subtracting the subtraction correction value ΔIM from
Correction value IM_AAnd output this to the adder 24c
Therefore, the addition output of this adder 24c is
It will be reduced in total, and this will be reduced to the automatic position controller 2
Work of tension leveler by sending to 4d
Direction to separate roll 4W from deflector roll 4D
To reduce the amount of intermesh,
Tension level by reducing the growth rate of
La elongation rate ε_LIs controlled within an allowable range. Conversely, ε_L<Ε
_LSTension leveler elongation ε_LIs too small
It is judged that it is a limit, and the process proceeds to step S11
Intermesh correction value IM_AIncrease correction value ΔIM to
The added value is the new intermesh correction value IM_AWhen
Then, by adding this to the adder 24c, the addition
That the addition output of the calculator 24c increases from the previous value
By sending this to the automatic position controller 24d,
Deflection the work roll 4W of tension leveler
ー Raise to the roll 4D side to increase the intermesh amount
To increase the growth rate of the tension leveler 4,
Tension leveler growth rate ε_LIs controlled within an allowable range.

In the above embodiment, the control device 1
The case where the elongation rate setting device 30, the pressure setting device 31, the intermesh setting device 32, and the speed reference setting device 33 are connected to 5 has been described, but the present invention is not limited to this.
The total elongation set value ε _TS , the pressure set value P _S , the intermesh set value IM _S, and the speed reference set value V _S may be input from a host computer that controls the rolling line.

In the above embodiment, the case where the present invention is applied to a so-called constant pressure / elongation rate control system in which the load of the skin pass mill 3 is kept constant and the total elongation rate is controlled by an elongation rate motor has been described. It is needless to say that the present invention can be applied to any other constant pressure / constant tension control system and elongation / tension control system without being limited thereto.

[0030]

As described above, according to the tension leveler control method of the present invention, the elongation rate of the strip in the skin pass mill and the elongation rate in the tension leveler are individually monitored, and the elongation rate of the skin pass mill is measured. Is within the setting range, when the elongation rate of the tension leveler exceeds the set upper limit value, the intermesh of the tension leveler is decreased to decrease the elongation rate of the tension leveler.
When the elongation rate of the tension leveler exceeds the lower limit setting, the intermesh of the tension leveler is increased, so when abnormal tension occurs in the tension leveler, it is possible to eliminate the abnormal rate with high responsiveness. The effect that stable operation can be achieved is obtained.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an example of intermesh control processing.

[Explanation of symbols]

 1 Input side bridle roll 2 Strip 3 Skin pass mill 4 Tension leveler 5 Output side bridle roll 6 Elongation rate motor 7 Differential gear 8 Drive motor 9 Skin pass mill motor 10 Hydraulic cylinder 15 Control device 16 Mill input side tension sensor 17 Mill output side tension Sensors 18 to 20 Pulse generator 21 Total elongation control section 22 Mill entry side tension control section 23 Mill exit side tension control section 24 Leveler elongation rate control section 24a Individual elongation rate calculator 24b Intermesh correction value calculator 25 Rotation speed control section

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B21B 37/56

Claims (1)

[Claims] 1. A method of controlling a tension leveler in which a strip that has passed through a skin pass mill is supplied, wherein the elongation rate of the skin pass mill and the elongation rate of the tension leveler are individually monitored, and the elongation rate of the skin pass mill falls within a set range. At one point, the intermesh is decreased when the elongation rate of the tension leveler exceeds the set upper limit value, and the intermesh is increased when the elongation rate of the tension leveler exceeds the set lower limit value. How to control the tension leveler.