JP2628964B2 - Equipment arrangement of hot strip finishing mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrangement of hot strip finishing mills, and more particularly to a hot strip finishing mill capable of accurately setting a strip profile on a discharge side of a final stand to a target value. For arrays.

[0002]

2. Description of the Related Art In a hot strip finishing mill, a control for adjusting a thickness distribution (plate profile) in a width direction and a flatness of a plate together with a plate thickness is performed.

[0003] In controlling the plate profile (plate crown), a crown control device installed in each rolling stand constituting the finishing mill is controlled so that the plate profile on the exit side of the final stand matches the target value. .

[0004] Therefore, usually, a plate profile meter for actually measuring the plate profile is installed on the exit side of the final stand of the finishing mill, and the result of measurement by the plate profile meter is used to obtain a plate of the product rolled at the final stand. The control deviation for the next rolled material is reduced by managing the profile and learning the model for controlling the plate profile.

In the above-mentioned plate profile control, for example, a control model formula represented by the following formula (1) can be used. In the case of a tandem rolling mill having N stands, each stand corresponds to formula (1). By formulating the following formulas and combining a total of N formulas, the plate profile on the exit side of the final stand can be obtained.

C _ri = α · C _rmi + β · C _ri-1 (1)

In the above formula (1), C _ri is a plate profile on the exit side of the ith rolling stand counted from the upstream side,
_rmi is the so-called mechanical crown of the stand, C
_ri-1 is the i _{-1st, that} is, the plate profile at the exit side of the former stand, α is the transfer rate of the mechanical crown, β
Is the genetic coefficient for the plate profile of the preceding stand. Hereinafter, these will be described in order.

The mechanical crown C _rmi of the above formula (1)
Is the mechanical change in the widthwise distribution of roll spacing caused by roll deflection, roll thermal expansion or roll wear due to rolling load. Now, the crown caused by the deflection of the roll by rolling load C _mpi, the crown due to thermal expansion of the roll C _MRhi, a crown with a roll wear putting a C _MRwi, the mechanical crown C _rmi is expressed by the following equation (2) It is.

C _rmi = C _mpi + C _mRhi + C _mRwi (2)

In the above equation (2), the crown C _mpi caused by the roll deflection is determined based on the load distribution in the width direction, based on (i) the deflection of the work roll and the backup roll (including the change due to the output of the crown control device), and (ii). considering initial crown like rolls, it is given by the function f ₁ represented by the following equation (3). Here, in this equation, P is the rolling load, b is the material width, and x is the output of the crown control device.

C _mpi = f ₁ (P, b, x) (3)

The crown (heat crown) _CmRhi due to the thermal expansion of the roll is obtained by _formulating the change of the roll crown accompanying the progress of rolling and cooling after rolling by a method such as approximation of a first-order response, and calculating each time constant and proportionality. Constants and the like can be determined by regression from experimental data.

When the above-mentioned heat crown is determined, the surface condition of the roll changes as black scale is formed or falls off as the rolling progresses in, for example, a hot strip finishing mill, and the friction coefficient and the heat transfer coefficient are changed. When the heat input from the strip to the roll changes due to the change in the heat input, this causes a heat crown estimation error, but this change in the heat input cannot be measured.

Further, the crown C _mRwi caused by the roll wear is _used.
Is expressed by the following equation (4) including the function f ₂ . However,
Cf is the wear coefficient, L is the pressure extension, and D is the roll diameter.

C _mRwi = Cf · f ₂ (P, L, b, D) (4)

In the above equation (4), Cf is determined by regression of the rolling result. Since the degree of wear of the roll changes depending on the material characteristics and the surface condition of the roll, this estimates the crown _CmRwi due to the roll wear. Error factors.

In the above equation (1), the transfer rate α is given by a function f ₃ represented by the following equation (5).

Α = f ₃ (h, Ld, Kch, ξ) (5)

Here, h is the exit side plate thickness, Ld is the contact arc length,
Kch is the plate width, the contact arc length, the regression coefficient changes by deformation resistance, etc., xi] is the shape change factor given by the function f ₄ that is expressed by the following equation (6).

Ξ = f ₄ (D, h, b) (6)

[0021] Also, the genetic factor β is given by the function f ₅ represented by the following equation (7). H is the thickness of the entry side plate.

Β = f ₅ (Kch, Ld, ξ, h, H) (7)

Since the transfer rate α in the above equation (5) and the genetic coefficient β in the above equation (7) both use the regression coefficient Kch and the shape change coefficient ら れ る similarly obtained regressively, α, β is recursively determined based on experimental results.

The crown control in a tandem finishing mill using the model formula represented by the above-described formula (1) as a basic control formula is described, for example, in JP-B-63-25.
At 845, one or both of the sheet crown and the sheet shape of the preceding material measured after rolling, and either or both of the sheet crown and the sheet shape calculated using the rolling conditions of the preceding material A method is disclosed in which the difference between the roll profile estimation errors is caused by an estimation error of the roll profile, the roll profile estimation error is calculated, learned, and used for calculating the setting of the succeeding material.

As a control technique using a plate profile meter, Japanese Patent Publication No. Sho 63-35325 discloses a continuous rolling mill in which a flatness detector and a crown detector are provided on the output side of the rolling mill. There is disclosed that a stand is provided with rolling load detectors, respectively, and based on signals from these detectors, the flatness and the crown of the delivery side plate of each stand are controlled to be a target value or an allowable range.

In plate profile control by a general hot strip finishing mill including the technique disclosed in the above publication, a plate crown is actually measured at or near the exit side of a final stand, and the measured value is used. Control.

Hereinafter, a conventional general plate profile control method will be described with reference to a specific example of a hot strip finishing and rolling mill having seven stands including a first stand F1 to a seventh stand F7.

First, assuming a pass (threading) schedule for performing finish rolling, the rolling load on each stand is predicted and calculated, and the exit side plate thickness of the finishing mill, that is, the exit side plate thickness h ₇ of the seventh stand. And the seventh stand target crown C _r7
^Aim sets the final target ratio crown R _c7 ^Aim (= _{Cr 7}
^Aim / h ₇₎ with obtaining the target crown C _ri ^Aim of side out each stand from the pass schedule with this
(= R _c7 ^Aim × h _i ) is determined.

Next, based on the above equation (1), a target mechanical crown C _rmi ^Aim for achieving the target crown C _ri ^Aim for each stand is determined, and a crown control device for achieving the target mechanical crown is determined. Determine the output.

[0030] Thereafter, the actual plate rolling, the plate crown C _r7 out of the final stand F7 measured by a plate profile meter is installed in the outlet side the stand, the actual delivery side crown C results from _r7 ratio crown R _c7 (= _Cr7 / h
₇ ) Ask for.

Next, assuming that the ratio crown on the exit side of each stand is equal to the actual ratio crown _Rc7 on the exit side of the seventh stand F7, the actual rolling load at each stand and the actual ratio crown _Rc7 are used to determine each stand. obtaining an error S _i from the equation (1) in the. That is, the _output side crown C _ri of the ith stand is _calculated as R _c7 × h _i , and the error S _i that satisfies the following equation (8) is determined. The mechanical crown _Crmi is calculated using the actual rolling load.

C _ri = α · C _rmi + β · C _ri-1 + S _i (8)

As described above, for each stand (8)
After obtaining the equation, learning for using the equation (8) for setting the crown of the next material is performed. Also, determine the appropriate mechanical crown C _mri for matching the side plate crown out of each stand using the error S _i to the target value, to change the crown control unit output for each stand to match the mechanical crown And perform feedback control.

[0034]

However, in the above-described conventional plate profile control, since the plate profile (plate crown) is actually measured at or near the exit side of the finishing mill, there are the following problems.

The plate model control uses the control model equation of the above equation (1), and the equations constituting the model equation are as follows:
As described above, it is determined by regression, and it is impossible to specify the error factor despite the fact that the error factors of the respective equations are different from each other. Therefore, even if the above equation (8) is applied to the next material, it is not always necessary. A high-precision control result was not obtained, which was a factor of increasing the variation in plate profile control accuracy.

Also, when performing the feedback control, since the control substance at each stand is unknown, it is assumed that the crown ratio between the stands is equal to the actual ratio crown on the exit side of the last stand as described above. Therefore, the control has to be performed, which also causes a decrease in the crown control accuracy.

In the case where the ratio crown is changed in the rolling stand, if the change is not properly performed, a plate shape defect (flatness defect) occurs due to a change in the residual stress distribution in the width direction.
That is, the ratio crown R _ci (=
C _ri / h _i change possible amount ΔR in the same stand)
_ci (= R _ci-1 −R _ci ) is limited by the plate shape. The turbulence of the plate shape is caused by buckling of the plate due to internal stress distributed in the width direction of the strip (plate). Therefore, the easiness of shape distortion caused by changing the crown ratio is more remarkable as the plate thickness is smaller. If the assumption that the ratio crown is equal between the stands is not correct, large shape disturbance will occur. There is fear.

Therefore, conventionally, in order to prevent the above-mentioned shape irregularity from occurring, the mechanical crown C _mri of the middle stage stand or the stand on the upstream side which is relatively thick and therefore hardly _suffers from a shape defect is changed. However, in this case, since the process from the stand where the mechanical crown was changed to the final stand is long, there is a problem that the plate profile control defect is likely to be newly generated by the rolling during the process. there were.

Further, since the reliability of the above assumption that the crown ratio between the stands is equal to the crown ratio on the exit side of the final stand is low, the control gain itself needs to be suppressed to a low level. It was in a state that had to be done.

The present invention has been made in order to solve the above-mentioned conventional problems, and is intended to accurately hit a plate profile on the exit side of a final stand to a target value without causing a shape defect in a strip. It is an object of the present invention to provide an arrangement of hot strip finishing mills capable of performing the above.

[0041]

According to the first aspect of the present invention, there is provided an arrangement of a hot strip finishing mill in which a plurality of rolling stands are connected in series, between two or more continuous stands. The above object has been achieved by installing a plate profile meter in each of the above.

The invention of claim 2 is the equipment arrangement of hot strip finishing mill rolling stands multiple, which are continuously provided, with each placed a plate profile meter between two or more stands, at least one The above object is also achieved by setting the thickness of the strip passing between the stands to be 4 mm or less and 2 mm or more.

[0043] The inventions of claim 3, in equipment arrangement ho <br/> Tsu preparative strip finish rolling mill according to the above Symbol claim 2, as between two or more stand for installing the plate profile meter is continuous By doing so, the above-mentioned object has been achieved similarly.

The inventions of claim 4, in the upper Symbol claim 1 or 3
In the arrangement of the hot strip finishing mill,
The object has been similarly achieved by installing a roll profile meter on a rolling stand sandwiched between successive stands on which a plate profile meter is installed.

[0045] The inventions of claim 5, above Symbol claim 1 or 2
In the arrangement of the hot strip finishing mill,
The above-mentioned object is similarly achieved by installing a flatness meter between stands.

[0046]

First, a preferred installation position of a plate profile meter installed between stands in the present invention will be described. However, the present invention is not limited to the arrangement of the plate profile meter at this position.

As described above, in the subsequent stage of the hot strip finishing mill, it is extremely difficult to significantly change the plate profile because it causes a defective plate shape in the product.

Generally, in order to perform rolling without disturbing the shape of the plate, it is necessary to perform the rolling while keeping the ratio crown of the plate constant.

As a result of various studies of the rolling phenomena, the present inventor has found that if a certain thickness is present, even if residual stress distributed in the width direction occurs due to deviation from the state where the ratio crown is constant, the shape of the plate can be reduced. It has been found that rolling can be performed without causing turbulence.

FIG. 1 is a diagram specifically showing an example of the relationship between the sheet thickness and the ratio crown change limit which do not disturb the plate shape, which is the basis of the above knowledge. The limit increases when the plate thickness is 2 mm or more.
It can be seen that the saturation gradually increases when it exceeds mm.

Here, the ratio crown change limit is the i-th limit.
The ratio crown change rate ΔR _ci (= R) which is the difference between the ratio crown R _{ci -1 (} value obtained by dividing the crown by the thickness of the central portion) on the entrance side of the stand and the ratio crown R _ci on the exit side of the stand.
_ci-1 −R _ci ).

FIG. 1 shows the experimental results. The reason why the ratio crown change limit is saturated when the plate thickness exceeds 4 mm as described above is presumed as follows. In a region where the plate thickness is large, buckling due to internal stress is unlikely to occur even when the ratio crown is changed, but it is considered that the presence of the internal stress makes it difficult to change the ratio crown.

For example, when the ratio crown is changed in a direction in which the ratio crown becomes smaller, compression acts on the center in the width direction and tension acts on the end in the width direction. As a result, the rolling load increases at the center in the width direction, and conversely, the rolling load decreases at the edge. Since this tendency becomes stronger as the sheet thickness increases, it is considered that an attempt to change the ratio crown results in a change in the distribution of the rolling load in the width direction, which limits the margin of change in the ratio crown.

Also, there is, of course, a limitation on the crown changeable amount of the crown control device. This is also considered to be a factor limiting the amount of change in the ratio crown on the thicker side.

Further, the genetic coefficient β of the equation (1) shown in FIG.
From the example of the relationship between the sheet thickness and the sheet thickness, β is small if the sheet thickness is large, but the disturbance due to subsequent rolling increases, so that the sheet profile changes by rolling to the final stand exit side, and as a result, the final product Since the plate profile control ability is reduced, even if the plate profile at the stage where the plate thickness is excessively large is measured, the measured value cannot be effectively used for control.

Therefore, the stand between the stands on which the plate profile meter is installed is preferably a stand between the stands in which the plate shape does not disturb even if the ratio crown is changed to some extent and the thickness of the passing strip is 2 mm or more. It is particularly preferable that the distance between stands is 4 mm or less. Further, when the thickness of the strip passing between the installation stands is 4 mm or less and 2 mm or more in this way, the most upstream stand in this range is more downstream than the measurement position. This is more preferable because the degree of freedom to change the ratio crown at the stand can be increased.

In the present invention, since the plate profile meter is installed not between the exit side of the finishing mill but between stands, the plate profile of the strip passing between stands is measured by the plate profile meter at the time of passing. The target ratio crown is determined from the target plate profile of the product, and the rolling ratio of the rolling stand upstream from the plate profile meter installation position is determined so that the target ratio crown matches the actual ratio crown obtained from the profile measurement result between the stands. The profile control device (roll bender or roll crossing angle adjusting device) is operated to perform feedback control.

By performing this feedback control, it is possible to always control the strip to the target plate profile between the stands at the plate profile measurement position, and thereafter, the strip is rolled under the condition that the ratio crown is constant, so that the finishing mill can be output. It is possible to accurately hit the plate profile of the product on the side with the target value.

On the other hand, if there is a deviation between the actual ratio crown obtained from the measurement result obtained by the plate profile meter installed between the stands and the target ratio crown between the stands, the deviation is shown in FIG. Since the ratio crown can be changed within the allowable range, the rolling stand on the downstream side of the plate profile meter installation position changes the ratio crown within the allowable range and rolls, thereby causing disorder in the plate shape. In addition, it becomes possible to hit the plate profile on the exit side of the final stand to the target value.

In the present invention, since the plate profile meters installed between the stands are installed at two or more locations, the number of stands with clear control entities is increased. As a result, the plate profile at two or more locations is obtained. Since the above-described feedback control or feedforward control can be performed using the actually measured value, the control accuracy can be further improved as compared with the case where the actual measurement is performed using one plate profile meter.

In the present invention, when the two or more stands on which the plate profile meters are installed are continuous, the plate profiles C are respectively provided on the exit sides of the successively provided rear stand and front stand. _ri, since it measures the C _ri-1 directly, a plurality of measured values on the basis Teso respectively aforementioned feedback control of the plate profile, it is possible to perform the feedforward control line using the measurement data obtained or By the off-line regression analysis, the accuracy of the genetic coefficient β in the model equation of the above equation (1) can be improved. As described above, the influence of the genetic coefficient β is small but causes an error in the model equation. Therefore, it is desirable to improve the accuracy of the genetic coefficient β.

In the present invention, when the roll profile meter is installed on a rolling stand sandwiched between continuous stands on which a plate profile meter is installed,
Wherein (1) necessary for crown calculations by formula, target stand F _i delivery side of the strip crown C _ri, strip crown C _ri-1 of the preceding stage stand delivery side, the crown and the roll by the roll of thermal expansion of the target stand F _i Since the sum (C _mRhi + C _mRwi ) of the crown due to wear and the like can all be measured, as a result, only error factors are the transfer rate α and the genetic coefficient β. Therefore,
The transcription rate α, genetic coefficient β
Can be optimized, the learning accuracy of the model equation can be improved, and the initial setting accuracy of the next rolling condition can be improved.

In the present invention, when a flatness gauge is installed between stands, in addition to the above-described high-precision plate profile control, for example, the flatness gauge is mounted on a rolling stand downstream from the plate profile meter installation position. By detecting the disturbance of the plate shape between the stands when performing the feedforward control of the profile, the plate profile control can be appropriately performed based on the detection result.

[0064]

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

FIG. 3 is a schematic configuration diagram showing a part of an equipment arrangement of a hot strip finishing mill according to an embodiment of the present invention.

The above arrangement of the present embodiment is a continuous rolling mill consisting of a total of seven stands, a first stand F1 to a seventh stand F7, and FIG. 3 shows a fourth stand F4 to a seventh stand F7. is there.

In the above-mentioned continuous rolling mill, each stand includes a plate profile control device 10, a load cell 12, and a plate thickness control device 14. In addition, as for these, the fourth stand F4 to the seventh stand F7 are illustrated by adding the suffixes A to D to the above reference numerals, respectively, but the first stand F1 to the third stand F3 which are omitted are also shown. It has the same configuration.

The fourth stand F4 to the seventh stand F7
The plate profile control arithmetic device 16 is connected to the plate profile control devices 10A to 10D, and the arithmetic device 16
Thus, a control signal for controlling the plate profile is input to each of these plate profile control devices 10A to 10D.

A thickness control arithmetic unit 18 is connected to the thickness control units 14A to 14D.
Thus, a control signal for controlling the thickness is input to each of the thickness control devices 14A to 14D.

The fourth stand F4 and the fifth stand F5
Between the fourth stands, between the fifth stands F5 and the sixth stand F6, between the fifth stands, and the final seventh.
On the exit side of the stand F7, there is a first plate profile meter 2
0A, a second plate profile meter 20B, and a third plate profile meter 20C.
The actually measured plate profile measured by the third to third plate profile meters 20A to 20C is input to the plate profile control arithmetic unit 16. Also, the fifth
A roll profile meter 22 is installed on the work roll of the stand F5.
The measured roll profile measured in 2 is similarly input to the plate profile control arithmetic unit 16.

The sixth stand F6 and the seventh stand F7
The first thickness gauge 24A and the second thickness gauge 24B are respectively installed between the sixth stand and the exit side of the seventh stand F7, and the actual measurement plate measured by the thickness gauges 24A and 24B is provided. The thickness is input to the thickness control arithmetic unit 18.

Further, a flatness meter 26 is provided between each of the fourth, fifth, and sixth stands so that the flatness of a strip passing between these stands can be measured. .

Next, the operation of this embodiment will be described.

In the present embodiment, the strip passing between the fourth stand F4 and the fifth stand F5 (between the fourth stands), that is, the strip rolled by the fourth stand F4 has a thickness of 4 mm or less and 2 mm. The pass schedule is set as described above.

In the present embodiment, the strip (rolled material) S rolled at the first to fourth stands F1 to F4 upstream of the fourth stand where the plate profile meter 20A is installed is the When the tip reaches the plate profile meter 20A, the plate profile at the tip is measured.

With respect to the strip S having reached the exit side of the fourth stand F4 by the first profile meter 20A between the fourth stands, the plate profile _Cr4 and the thickness of the central portion thereof are obtained.
After measuring h ₄ , these measured values are input to the plate profile control arithmetic unit 16, where they are converted into the ratio crown R _c4 . The fourth based on this measured value
The plate profile control devices 10A and 10A before the fourth stand and the plate profile control devices of the first to third stands (not shown) are arranged so that the ratio crown on the exit side of the stand F4 matches the target ratio crown _Rc4 ^Aim obtained in advance. The control change amount is output from the profile control calculation device 16 to perform feedback control.

By the feedback control, the fourth
After measuring the plate profile at the tip of the strip between the stands, the plate profile on the exit side of the fourth stand F4 can be matched with the target ratio crown on the exit side of the stand F4. Therefore, thereafter, it is possible to advance the rolling by the downstream stands F5 to F7 under the condition of the fixed ratio crown, and the product strip rolled by the seventh stand F7 can be moved to the target plate without causing disorder of flatness. You can hit your profile.

As described above, in the present embodiment, since the plate profile meter 20A is installed between the fourth stand F4 and the fifth stand F5, the plate crown _Cr4 on the exit side of the fourth stand can be _replaced with the conventional one. Since it is possible to obtain the actual value instead of the assumed value as described above, it is possible to greatly improve the control accuracy of the plate profile.

Further, since the thickness of the strip passing between the fourth stands where the plate profile meter 20A is installed is set to be 4 mm or less and 2 mm or more, the plate is not used in the upstream stands F1 to F4. There is a high degree of freedom to change the crown without disturbing the shape. Therefore, the error S ₄ in the fourth stand F4 is directly calculated by the same method as described above using the equation (8), the error S ₄ is reduced, and the measured ratio crown R _c4 in the stand is calculated. Target ratio crown R _c4 ^Aim
The roll deflection C due to the rolling load is adjusted to match
By changing the crown control amount to correct _mp4 , it is possible to execute highly responsive feedback control.

In addition to performing the feedback control described above, if there is a deviation between the ratio crown based on the actual measurement and the target value between the fourth stands, the final product crown and the target crown on the exit side of the seventh stand are compared with each other. Profile control arithmetic unit 16 so as to reduce the deviation of
From the stand downstream of the fourth stand F4, that is, the fifth stand
Stand F5, sixth stand F6, and seventh stand F7
The control change amount is output to the load cells 12B, 12C, and 12D attached to the control unit, and feedforward control is performed.

That is, according to the deviation between the ratio crown and the target ratio crown based on the actual measurement of the strip tip, the rolling stand F located downstream of the profile meter 20A.
The required control amounts calculated by the plate profile control calculation device 16 are also output to the plate profile control devices 10B to 10D arranged at 5 to F7, respectively, in order to correct the plate profile at the tip of the strip. However, in these downstream rolling stands 10B to 10D, since the controllable amount of the plate profile is small as described above,
The output to the plate profile control devices 10B to 10D needs to be restricted by calculation by the control calculation device 16 so as to be within the allowable range of flatness.

However, in the present embodiment, the strip whose plate profile is measured by the plate profile meter 20A has a plate thickness of 4 mm or 2 mm or more. Since a relatively large allowable range of the flatness can be ensured, the plate profile control can be reliably performed without causing a plate shape (flatness) defect.

The following two methods are used to control the downstream stands F5 to F7 to bring the final ratio crown closer to the target value based on the measured ratio crown _Rc4 on the exit side of the fourth stand. Can be mentioned.

In the first method, the proportional integral control based on the deviation between the ratio crown R _c4 at the exit side of the fourth stand F4 and the target ratio crown R _c4 ^{Aim at} the exit side of the fourth stand F4 is simply applied to the subsequent stands F5 to F7. It is a method to control.

The second method is to predict a plate profile on the exit side of the final stand when rolling is advanced to the final stand in accordance with a preset pass schedule based on the above ratio crown R _c4 , and calculate the predicted output profile. Downstream stands F5 to F in order to bring the side plate profile close to the target value
7 is a control method.

In the latter stand where the strip thickness is reduced, the shape is easily disturbed as described above, so that the changeable amount of the ratio crown _{Rci in} the _subsequent i-th stand is limited. Therefore, it is important to consider how to approach the target in the limit determined by the changeable amount ΔR _ci of the ratio crown determined by the following equation (9), in order to secure the passability.

ΔR _ci = f ₆ (h, b, D) (9)

In the first method, the changeable amount of the ratio crown in the downstream stand cannot be taken into account. However, in the second method, this can be taken into account. Is more advantageous than the first method.

In this embodiment, even after the leading end of the strip has passed between the fourth stands, the plate profile of the strip passing between the stands can be changed by continuing the measurement with the plate profile meter 20A. Even if there is a deviation between the measured plate profile and the target value due to changes due to thermal expansion or progress of wear, etc., it is possible to correct the deviation, so that the plate profile of the product always matches the target value. It becomes possible.

Next, the first plate profile meter 20
A description will be given of the result of actually performing the plate profile control in order to clarify the effect of the control method using the actually measured plate profile according to A.

When rolling a sheet bar having a thickness of 30 mm according to the pass schedules shown in Tables 1 and 2 below, the distance between the stands where the plate profile meters are installed is changed, and the plate is placed at a position where the thickness is different. In addition to measuring the profile, feedback control is performed for the stand on the upstream side of the plate profile meter installation position based on the measured plate profile. Plate profile control was performed, which performed forward control.

[0092]

[Table 1]

[0093]

[Table 2]

FIG. 4 shows the difference between the measured plate profile on the exit side of the final stand and the target value obtained when the above-mentioned plate profile control was performed and the plate profile control accuracy (μm
) And the correlation between this and the passing plate thickness (mm) between stands on which the plate profile meter is installed.

As is apparent from FIG. 4, the control accuracy is improved when the passing plate thickness is 2 mm or more, and the control accuracy is reduced when the passing plate thickness exceeds 4 mm, and the control effect is finally lost.

The improvement of the control accuracy at a plate thickness of 2 mm or more is due to the fact that the ratio crown change limit determined from the shape limit rapidly increases as shown in FIG. It is shown in FIG.
It is understood that the genetic coefficient β becomes smaller and the number of times of rolling until reaching the final product increases as shown in FIG.

From the above description, it is preferable that the position of the plate profile meter for measuring the plate profile used for the feedback control and the feedforward control is between stands where the thickness of the passing strip is 4 mm or less and 2 mm or more. It turns out there is.

In this embodiment, the first plate profile meter 20A is installed between the fourth stands,
Since the second plate profile meter 20B is installed between the fifth stands which are continuous between the fourth stand, when performing the above-mentioned plate profile control based on the actually measured plate profile obtained by the first plate profile meter 20A. The control for the fifth stand can be performed using the measured plate crown _Cr5 on the exit side of the fifth stand F5 obtained by the second plate profile meter 20B.

Therefore, even in the fifth stand F5, it is possible to perform the plate profile control based on the actual measured value instead of the assumed value, so that the control accuracy can be further improved.

In this embodiment, as described above, the first plate profile meter 20A measures the crown _Cr4 on the exit side of the fourth stand F4, and the second plate profile meter 20B measures the crown _Cr4 on the exit side of the fifth stand F5. Plate crown _Cr5 ,
Further, the roll profile C _MR5 work rolls of the same stand F5 roll profile meter 22, the rolling load P ₅ of the stand F5 were measured by further load meter 12B, the plate profile processing device these measured values 16
To enter.

[0102] In this arithmetic unit 16, determined by calculating the crown C _mp5 due to deflection rolls of the same stand F5 by the expression (6) from the rolling load P ₅ of the fifth stand F5, wherein it together with the measured value (1 ) Is applied to the model formula to obtain the above (5) by a recursive method.
By calculating the mechanical crown transfer rate α in the equation and the genetic coefficient β in the equation (7), and changing the learning correction coefficients (regression coefficient K _ch , shape change coefficient ξ) in these calculation model equations, the next rolling is performed. It is possible to improve the accuracy of the initial setting of the material.

This will be described in more detail. In this embodiment, the plate profile meters 20A and 20B are arranged between two stands sandwiching one rolling stand provided with a roll profile meter. Accordingly, the equation (1) necessary for crown calculations by target stand F _i (i = 4) the delivery side of the strip crown C _ri, of the front stand delivery side strip crown C _ri-1, the same target stand F _i Since the sum (C _mRhi + C _mRwi ) of the crown due to the thermal expansion of the roll and the crown due to the abrasion of the roll can all be measured, as a result, only error factors are the transfer rate α and the genetic coefficient β. Therefore, the transcription rate α and the genetic coefficient β can be easily optimized by a recursive technique or the like. Note that the transfer rate α and the genetic coefficient β vary depending on the temperature distribution in the width direction of the material, the material characteristics, and the like, and the change due to the difference between stands is small. Applying this to a stand does not pose any major problems.

In the present embodiment, the first plate profile meter 20A and the second plate profile meter 20B determine the center plate thickness h _{4 at the} exit side of the fourth stand F4 and the center plate thickness at the exit side of the fifth stand F5. together to measure the thickness h _5,
Since the center thickness h ₆ on the exit side of the sixth stand F6 can be measured by the thickness gauge 24, these measured thicknesses are input to the thickness control arithmetic unit 18 and the arithmetic unit 1
In step 8, the actual measured value is compared with a preset target stand-to-stand sheet thickness, and the sheet thickness control device 1 is controlled to reduce the deviation.
By changing the control amount for No. 4, it is possible to control the plate thickness with high accuracy.

Further, as described above, by installing the first profile meter 20A between the third fourth stand counted from the downstream side, the difference in the thickness of the strip passing through the measurement position in the width direction can be reduced. Can also be detected. Since the position between the fourth stands is a position where the plate profile can still be corrected, if there is a difference in plate thickness in the width direction, the fifth stand F5 and the sixth stand F6 located on the downstream side thereof.
By performing feedforward control on the seventh stand F7 so as to eliminate the deviation of the plate thickness occurring in the width direction, it is possible to prevent meandering from occurring in the final product of the strip S. By improving the meandering of the strip S in this manner, it is possible to reduce a passing trouble such as narrowing when the leading end and the trailing end pass.

Further, in this embodiment, since the flatness gauges 26 are provided between the stands, the shape of the strip S passing between the stands is measured by the flatness gauges 26, and the actual measurement plate is measured. By inputting the shape to the plate profile control arithmetic unit 16 and correcting the control correction amount from the detected values, it is possible to appropriately prevent the plate shape from being disturbed due to the plate profile overcontrol.

As described in detail above, according to the present embodiment, the plate profile meter 20A is installed between the stands where the thickness of the strip passing therethrough is 4 mm or less and 2 mm or more. Based on the above, by performing feedback control on the rolling stands upstream of the installation position of the plate profile meter 20A, the strip passing between the stands can be matched with the target plate profile at that position, By performing feedforward control on the downstream side stand, the plate profile meter 20 can be used.
Even if there is a deviation between the measurement result by A and the target value, the product plate profile on the exit side of the final stand can be hit to the target value. Actually, in the conventional method, the error of the plate profile control accuracy was 30 μm, but could be reduced to 10 μm or less.

Further, according to the above-mentioned feedback control, compared to the case where a sheet profile meter is installed on or near the outlet side of the tandem rolling mill as in the prior art, the material required until the feedback control is performed is reduced. The length can be greatly reduced. By the way, when converting from the fourth stand exit side to the seventh stand exit side into the strip length,
For example, it is about 20 m.

Further, according to the feedforward control, since the plate profile control can be performed based on the actually measured value measured by the plate profile meter 20A, the control is greatly controlled as compared with the conventional predictive control. Accuracy can be improved.

Further, according to this embodiment, the plate profile between the stands, which was conventionally unknown, was found out, and the plate profile meter was installed on a rolling stand sandwiched between two continuous stands. Since the roll profile for the rolling stand can be obtained as an actual measurement value by the roll profile meter,
It becomes possible to directly measure the conditions of the sheet profile and the roll profile on the entrance and exit sides of the rolling stand.

Therefore, the transfer rate α of the mechanical crown,
Since the deviation of the genetic coefficient β from the model formula can be grasped quantitatively and directly, the accuracy of the control model formula can be greatly improved, and the initial setting accuracy for each control device at the time of the next material rolling Can be greatly improved.

Although the present invention has been specifically described above, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof.

For example, in the above embodiment, the finish rolling mill
Although the description has been made of the stand, the present invention is not limited to this.

In the finishing mill comprising the seven stands, the first plate profile meter 20A is passed through the finishing plate mill having a thickness of 4 mm.
mm or less, it was installed between the 4th stand that was 2 mm or more,
It is not limited to this.

The installation positions and the numbers of the plate profile meter, the roll profile meter, and the flat thermometer are as follows.
The present invention is not limited to the one shown in the above embodiment, but can be arbitrarily changed, and is not limited to the case where the stands where the plate profile meters are installed are continuous.

In the above-described embodiment, the case where the thickness gauge is installed between the sixth stand before the final seventh stand is shown, but a plate profile meter may be installed instead of the thickness gauge. . However, since the plate thickness is usually too thin between the stands, the degree of freedom in controlling the plate profile is extremely low. Therefore, it is advantageous from the economical point of view to install a thickness gauge as in the above embodiment between the last stands.

[0116]

As described above, according to the present invention, the plate profile on the exit side of the final stand can be hit with the target value with high accuracy without causing a shape defect in the strip.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the thickness of a plate passing between stands and the ratio crown change limit.

FIG. 2 is a diagram showing the relationship between genetic coefficient β and plate thickness.

FIG. 3 is a schematic configuration diagram showing a part of an equipment arrangement of a hot strip finishing mill of one embodiment according to the present invention.

FIG. 4 is a diagram showing a relationship between a plate thickness at a stand-to-plate profile meter installation position and control accuracy.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Sheet profile control device 12 ... Load meter 14 ... Sheet thickness control device 16 ... Sheet profile control arithmetic device 18 ... Sheet thickness control arithmetic device 20 ... Sheet profile meter 22 ... Roll profile meter 24 ... Sheet thickness meter 26 ... Smoothness meter

Continuing from the front page (72) Kinryo Kaneda 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Works, Ltd. Inside the Chiba Works (72) Inventor Hideyuki Yuzawa 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Corporation Inside the Chiba Works (56) References JP-A-5-277534 (JP, A)

Claims (5)

(57) [Claims] 1. A hot strip finishing mill in which a plurality of rolling stands are connected in series, wherein a plate profile meter is installed between two or more continuous stands. Rolling mill equipment arrangement. 2. An equipment arrangement of a hot strip finishing mill in which a plurality of rolling stands are connected in series, wherein a strip profile meter is provided between two or more stands and a strip passes between at least one of the stands. A hot strip finishing and rolling mill, wherein the sheet thickness is set to be 4 mm or less and 2 mm or more. 3. The hot strip finishing and rolling mill according to claim 2, wherein the two or more stands on which the plate profile meter is installed are continuous. 4. The arrangement of a hot strip finishing mill according to claim 1 , wherein the roll profile meter is installed on a rolling stand sandwiched between continuous stands on which the plate profile meter is installed. 5. The equipment arrangement of a hot strip finishing mill according to claim 1, wherein a flatness meter is additionally provided between the stands.