JP3348832B2 - Meander control method in rolling mill - 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 for suppressing meandering of a rolled sheet generated during rolling by constant pressure reduction control in temper rolling or the like.

[0002]

2. Description of the Related Art As a method of suppressing the meandering by temporarily shifting to the localization reduction control when the meandering of the plate to be rolled exceeds the allowable range during the constant pressure reduction control, see, for example, Japanese Patent Application Laid-Open No. 7-24.
There is a meandering suppression method described in JP-A-515-515.

In the method described in the above-mentioned publication, the rolling load along the roll axis direction between the upper and lower work rokes is made constant by individually operating the hydraulic pressure reduction cylinders on the operation side and the drive side which can be operated independently. Temper rolling is performed by performing constant-pressure reduction control so as to achieve. When the pressure is increased from the mill open state to the mill closed state, the respective oil column positions of the hydraulic pressure reduction cylinders on the operation side and the drive side when the target rolling load is first reached are stored, and the constant pressure During the rolling of the plate to be rolled by the lower control, the deviation between the positions of the two oil columns is monitored.

When it is detected that the deviation of the oil column position is equal to or greater than a predetermined amount, it is evaluated that the meandering has occurred more than allowable, and the control is switched from the constant pressure reduction control to the localization pressure reduction control. Subsequently, during rolling by the localization reduction control, the deviation of the reduction force of the hydraulic reduction cylinder on the operation side and the drive side is monitored, and if it is detected that the deviation of the reduction force is equal to or less than a predetermined specified amount, the meandering is suppressed. As a result, the control returns to the constant pressure reduction control.

In the conventional meandering suppression method, when switching from the constant pressure reduction control to the localization reduction control, the positions of the respective oil columns of the hydraulic pressure reduction cylinders on the operation side and the drive side reach the stored target rolling load. When the roll gap during the localization reduction control is increased from the mill open state to the mill closed state, the target It is made equal to the roll gap when the rolling load is reached.

[0006]

However, in the meandering suppressing method, the roll gap at the time of first reaching the target rolling load is used as the roll gap for the localization reduction control, that is, the shape of the plate to be rolled is taken into consideration. The non-roll gap is used as a fixed value over the entire length of the rolled sheet. As a result, although there is a great possibility that the roll gap is effective for suppressing meandering immediately after mill closing, in other parts, the meandering of the plate to be rolled is temporarily promoted without being able to cope with the shape change of the plate to be rolled. In addition, there was a possibility that the roll gap did not correspond to the plate shape and shape defects such as one-sided stretching and squeezing occurred.

The present invention has been made in view of the above-mentioned problems, and provides a meandering suppressing method in a rolling mill capable of increasing rolling accuracy during localization reduction control and performing more stable meandering. The challenge is to do.

[0008]

According to a first aspect of the present invention, there is provided a method for controlling meandering in a rolling mill, wherein a rolling force is controlled to a target rolling load by each of an operating-side and a driving-side rolling device. In a meandering control method by a rolling mill that can select a constant pressure reduction control to perform and a localization reduction control to control a roll gap to a predetermined value, when the meandering amount of the plate to be rolled exceeds a predetermined threshold, the control is switched to the localization reduction control. A method of returning to the constant pressure reduction control when the meandering amount falls within a predetermined threshold value, wherein a moving average of the roll clearance during the constant pressure reduction control is used as the roll clearance during the localization reduction control. It is characterized by the following.

In the present invention, during the constant-pressure rolling in a state where the meandering amount is within a predetermined threshold value before switching to the localization reduction control, that is, until the actual rolled plate just before switching to the localization reduction control, The moving average of the roll gap in a state where the constant-pressure rolling control is properly performed according to the shape of the roll is used as the roll gap for the localization reduction control.

As a result, at the time of the localization pressure reduction control, the roll gap is set to a roll gap that can be sufficiently estimated to match the actual plate shape, and the roll gap according to the plate shape and more stable meandering suppression are realized. You.

According to a second aspect of the present invention, there is provided a meandering suppression method for a rolling mill, wherein a constant pressure reduction control for controlling a target rolling load by a reduction device on each of an operation side and a drive side, and a roll clearance to a predetermined value. In a meandering control method using a rolling mill capable of selecting the localization reduction control, switching to the localization reduction control is performed when the meandering amount of the plate to be rolled exceeds a predetermined threshold, and further, when the meandering amount falls within the predetermined threshold, the constant pressure reduction is performed. A method of returning to the down control, in which the roll gap at the time of the above-described localization reduction control is a moving average of the roll gap during the constant pressure reduction control, and then the roll clearance at the time of previously switching from the localization reduction control to the constant pressure reduction control. And the roll gap is selected and used by setting a high priority when selecting the roll gap.

Following the moving average of the roll gap during the constant pressure reduction control, the roll gap when switching from the localization reduction control to the constant pressure reduction control is a roll gap in which the meandering is at a predetermined threshold. , Even with this roll gap,
Meandering control more stable than before is realized.

Here, the “roll gap at the time of switching from the localization pressure reduction control to the constant pressure reduction control before” is not necessarily 1
The method is not limited to this, and includes a case in which a plurality of switching operations have been performed in the past, indicating the plurality of roll gaps.

According to the present invention, for example, if the moving average of the roll gap during the constant pressure reduction control immediately before the roll gap is presumed to be most suitable for the plate shape is used as the roll gap if the plate shape exists. If not, the roll gap used before it is presumed that it matches the plate shape next is selected and used as the roll gap to perform the localization reduction control. If the two roll gap information are not present, the constant pressure reduction control may be performed using the roll gap at the time when the target load force is reached during the constant pressure reduction control as in the related art.

That is, normally, the moving average of the roll gap during the constant pressure reduction control immediately before it is presumed to be the most suitable for the plate shape is selected and used. If not, or if the value is insufficient due to lack of data or the like, the roll gap used previously, which is presumed to conform to the plate shape, is selected, and meandering is effectively suppressed.

[0016]

Next, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a temper rolling mill (skin pass mill) will be described as an example of a rolling mill. here,
The temper rolling mill is a rolling mill that applies a light reduction of 2 to 3% or less for adjusting the material quality of the sheet after annealing and correcting the flatness.

In the rolling equipment using the skin pass mill according to the present embodiment, as shown in FIG. 1, the entrance bridle roll 2 and the exit bridle roll 3 are arranged before and after the skin pass mill 1 so as to be rolled. Temper rolling is performed with a predetermined tension applied to the plate 4.

Here, although not shown, a payoff reel, an uncoiler leveler, an entrance shear, and a welding machine are arranged upstream from the entrance bridle roll 2, for example. On the downstream side of the side bridle roll 3, for example, an output side shear and a tension reel are arranged. Then, the tail end of the preceding plate and the leading end of the following plate are joined by a welding machine, so that the plate 4 to be rolled is continuously temper-rolled by the skin pass mill 1 while being rolled on the tension reel. It is wound up.

As shown in FIG. 2, the skin pass mill 1 includes a pair of upper and lower work rolls 5a and 5b and backup rolls 6a and 6b, and a bearing box of the lower backup roll 6a so as to reach a target rolling load. The operation side (WS) and the drive side (DS) hydraulic pressure reduction cylinders 7a and 7b provided at the lower part of the vehicle respectively apply a reduction force individually. Each of the hydraulic pressure reduction cylinders 7a, 7b
Is controlled by a hydraulic servo valve (not shown) of the hydraulic servo mechanism.

The rolling forces of the hydraulic rolling cylinders 7a and 7b are detected by load cells 8a and 8b, and the load cells 8a and 8b can supply a load signal to the controller 9.

Further, oil column detectors 10a and 10b for detecting the positions of the oil columns of the hydraulic pressure lowering cylinders 7a and 7b, respectively, are provided. Each of the oil column detectors 10a and 10b can supply the detected position signal to the controller 9. It has become.

An optical type meandering detector 11 is arranged on the upstream side of the skin pass mill 1 so that the detected meandering amount of the plate 4 to be rolled can be supplied to the controller 9.
In FIG. 1, reference numeral 11a indicates the camera side, and reference numeral 11b
Represents the light source side.

As shown in FIG. 3, the controller 9 includes a main control unit 12, a constant pressure reduction control unit 13, and a localization reduction control unit 14, and a roll gap determination unit 15
Having.

The constant pressure reduction controller 13 includes a main controller 12
To control the hydraulic pressure of the hydraulic pressure reduction cylinders 7a and 7b based on the load signals from the load cells 8a and 8b to control the hydraulic pressure reduction cylinders 7a and 7b to the target reduction force.

The localization reduction control unit 14 includes the main control unit 12
, And based on the roll gap selection information 17 selected by the roll gap determination unit 15, the positions of the oil columns of the hydraulic pressure reduction cylinders 7a and 7b on the operating side and the drive side are forcibly set. The position of the oil column selected at 15 is set, and the roll gap between the work rolls 5a and 5b is controlled to be constant.

The roll gap determining section 15 includes a roll gap information storage section 15A and a roll gap selecting section 15B. The roll gap information storage unit 15A stores the oil column detector 10a,
Based on the signals from the load cell 10b and the load cells 8a and 8b, the operating side and the driving side rolling force are monitored. The position of the oil column is indicated by the third roll gap information 16C.
To be stored. Also, when it is determined that the constant pressure reduction control is being performed, the oil column position is input for each predetermined sampling time unit for each of the operation side and drive side oil column positions,
For example, the moving average L is calculated based on the following equation (1) and stored or updated as the first roll gap information 16A. Here, L ₀ : the immediately preceding moving average value L _N : the position of the sampled oil column N: the number of times of sampling of L ₀ .

Further, the roll gap information storage section 15A
When the switch from the localization pressure reduction control to the constant pressure reduction control is detected, the current roll gap selection information 17 is stored as the second roll gap information 16B. The first to third roll gap information 16A to 16C are initially cleared at a predetermined timing by the main control unit 12.

The roll gap selecting section 15B operates according to a command from the main control section 12, and as shown in FIG. 4, if data is stored in the first roll gap information 16A, the first roll gap information is stored. The data stored in the information 16 </ b> A is stored in the roll gap selection information 17, and the data is used by the above-described localization reduction control unit 14.

If it is determined that the first roll gap information 16A does not exist, it is checked whether data is stored in the second roll gap information 16B.
The second roll gap information 16B is stored in the roll gap selection information 17. When it is determined that the second roll gap information 16B does not exist, the data stored in the third roll gap information 16C is stored in the roll gap selection information 17.

Further, as shown in FIG. 5, the main controller 12 controls the first to third roll gap information 16A to 16C.
16C is cleared to zero (step 1), and in the normal state, an operation command is supplied to the constant pressure reduction controller 13 (step 2). Next, on the basis of the signal from the meandering detector 11, the meandering amount is set to the first threshold 18A in a predetermined sampling time unit.
(Step 3). If it is determined that the value exceeds the first threshold 18A, the roll gap selecting unit 15B is activated (Step 4), and the constant pressure reduction control unit 13 is operated.
Is supplied (step 5), and an operation command is supplied to the localization reduction controller 14 (step 6).

Further, during the above-described localization pressure reduction control, it is determined whether or not the amount of meandering is within a second threshold value 18B smaller than the first threshold value 18A based on a signal from the meandering detector 11 at a predetermined sampling time unit. (Step 7) If it is determined that the meandering amount is within the second threshold value 18B, a stop command is supplied to the localization reduction control unit 14 (Step 8) and an operation command is supplied to the constant pressure reduction control unit 13 (Step 8). 2).

The main controller 12 controls the rolled plate 4
In order to prevent the occurrence of driving flaws on the upper and lower work rolls when the welding joint points between the two pass through the skin pass mill 1, the oil column positions of the hydraulic pressure reduction cylinders 7a and 7b are respectively detected before passing through the welding joint points. The position of the lower work roll is rapidly lowered (mill-opened) based on the detection signals of the devices 10a and 10b. Next, the lower work roll is raised so as to attain the target rolling load, and the next temper rolling of the plate to be rolled is performed.

During the mill open operation, the first to third roll gap information 16A to 16C are cleared to zero. This is because the previous information cannot be used because the rolled plate 4 is changed and the tendency of the plate shape is different.

Further, in the above description, the meandering amount is directly determined by the meandering detector 11 arranged in front of the mill. However, as in the conventional example, during the constant pressure reduction control, the operation side and the drive side are controlled. The meandering amount may be evaluated based on the difference between the positions of the oil columns and the difference between the reduction forces on the operation side and the drive side during the localization reduction control.

Next, an example of the operation of the apparatus having the above configuration will be described with reference to FIG. When the mill is closed and the reduction forces of the operation side and drive side hydraulic reduction cylinders 7a and 7b both reach the target reduction force ((C) in FIG. 6).
), The roll gap information storage unit 15A stores the oil column positions on the operation side and the drive side at that time in the third roll gap information 16C.

Then, temper rolling is performed in a constant pressure reduction control state. If the meandering amount immediately exceeds the first threshold value 18A in this state, the state is switched from the constant pressure reduction control state to the localization reduction control state, and the meandering suppression processing is performed.

At this time, since no data is stored in the first and second roll gap information 16A, 16B yet,
The third roll gap information 16C stored as the data during the localization reduction control is used as the roll clearance selection information 17, and the roll clearance when the mill is closed and the target reduction load is initially attained. Done.

Subsequently, the meandering amount is suppressed and the second threshold 18
If it is determined to be B or less, the control returns from the localization pressure reduction control to the constant pressure reduction control. At the time of this return (timing (B) in FIG. 6), the data of the roll gap selection information 17 is stored in the second roll gap information 16B.

Further, during the constant pressure reduction control, the hydraulic pressure reduction cylinders 7 on the operation side and the drive side are provided at predetermined sampling intervals.
a and 7b are detected and the moving average is calculated.
The first roll gap information 16A is updated (timing (A) in FIG. 6).

Subsequently, when the meandering amount becomes equal to or more than the first threshold value 18A, the state is switched from the constant pressure reduction control state to the localization reduction control state, and the meandering suppression processing is performed. At this time, since the data is stored in the first roll gap information 16A having a higher priority, the first roll gap information 16A is used as the roll gap selection information 17 as the oil column position at the time of localization pressure reduction.

Further, when the meandering is suppressed and the meandering amount is determined to be equal to or less than the second threshold value 18B, the control is returned from the localization reduction control to the constant pressure reduction control. At the time of this return (timing (B) in FIG. 6), the data of the roll gap selection information 17 is stored in the second
This is stored in the roll gap information 16B.

Subsequently, similarly to the above, during the constant pressure reduction control, the oil column positions of the operation side and drive side hydraulic pressure reduction cylinders 7a and 7b are detected at predetermined sampling intervals, and a moving average is obtained. The one roll gap information 16A is updated (timing (A) in FIG. 6).

If it is determined that the joining portion of the plate to be rolled 4 passes during the constant pressure reduction control, the lower work roll is forcibly lowered and the mill open operation is performed, and the lower work roll is opened for a predetermined time. Then, the lower work roll is raised so that the target rolling load is attained, and temper rolling of the next rolled sheet is performed.

As in the above operation example, when rolling the leading end of the plate 4 to be rolled, the first and second roll gap information 1
Since there is no data of 6A and 16B, the roll gap at the time of the target reduction load is used in the localization reduction control as in the past. The localization reduction control is performed in the roll gap based on the first or second roll gap information 16A, 16B estimated to be the roll gap according to the plate shape of the above.

As a result, in localization pressure reduction control at least at a position other than the end of the plate 4 to be rolled, there is no or little increase in meandering, and stable meandering is suppressed. This also leads to shortening the time of the localization reduction control in which the surface property of the plate is inferior to that of the constant pressure reduction control.

Moreover, since the localization reduction control is performed at the roll gap matched to the plate shape, the occurrence of shape defects such as ear extension can be suppressed to a small extent, and the surface properties of the plate during the localization reduction control can be improved as compared with the prior art.

In the above embodiment, the roll gap (oil column position) at the time of the localization reduction control is selected from the three roll gap information 16A to 16C, but only the first roll gap information 16A is used. It may be used unconditionally as the position of the oil column (roll gap) during localization reduction control.

In this case, by sampling information on the position of the oil column at an early stage from the mill close, the position of the oil column (roll gap) for the localization reduction control with respect to the meandering at the tip end of the rolled plate 4 is determined. Third roll gap information 16C
The same value as (the position of the oil column when the target rolling load is reached) can be obtained.

Alternatively, only the first roll gap information 16A and the second roll gap information 16B may be used as the oil column position (roll gap) at the time of the localization reduction control. In the above embodiment, the first to third roll gap information 16
The priority is increased in the order of A to 16C, and it is determined whether there is the first roll gap information 16A or the like, and the roll gap information to be used is selected. However, the selection method is not limited to this. For example, when the sampling number N is equal to or more than a predetermined value, the first roll gap information 16A is used unconditionally, and when the sampling number N is less than the predetermined value, the second roll gap information 16B is used. The second roll gap information 1
If 6B is not stored, the third roll gap information 1
6C may be used.

That is, if the number of samples is equal to or more than the predetermined value, the first roll gap information 16A is used to sufficiently correspond to the results of the shape of the rolled plate 4 to be processed. If the value is less than the value, the second roll gap information 16B which may correspond to the result of the shape of the plate 4 to be rolled next may be used.

The above embodiment is an example in which the present invention is applied to meandering suppression in the hot rolling skin pass mill 1, but it can also be applied to a skin pass mill for a surface treatment line, an pickling line, and the like. Further, the present invention is not limited to a skin pass mill, but may be applied to other rolling mills such as a cold tandem rolling mill as long as rolling is performed under constant pressure reduction control.

[0052]

FIG. 7 shows the case where the meandering suppression according to the above embodiment is performed (see FIG. 7 (b)) and the case where the target reduction load is reached at the time of mill closing as the roll gap during the localization reduction control as in the conventional example. It is an example of a result in the case where the position of the oil column at this time is used as a fixed value over the entire length of the steel strip (see FIG. 7A).

As can be seen from FIG. 7, an oil column (fixed value) at the time of reaching a target rolling load whose plate shape is not so reflected is applied to the rolled plate 4 as the roll gap during the localization rolling control. When used as a fixed value over time, the amount of meandering is promoted.

On the other hand, in the meandering suppression according to the above embodiment according to the present invention, the meandering amount is suppressed within ± 8 mm over the entire length of the rolled plate 4 (steel strip), and extremely stable control is performed. .

This is because a roll gap having a leveling or the like corresponding to the actual plate shape was used.

[0056]

As described above, when the meandering suppression method in the rolling mill of the present invention is adopted, the meandering suppression control for the meandering is performed in the roll gap corresponding to the plate shape, thereby suppressing the meandering. This is performed early and has the effect of suppressing the occurrence of shape defects such as squeezing during the localization pressure reduction control.

[Brief description of the drawings]

FIG. 1 is a diagram showing a device configuration according to an embodiment of the present invention.

FIG. 2 is a view showing a skin pass mill according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a controller according to the embodiment of the present invention.

FIG. 4 is a diagram showing a processing flow of a roll gap selecting unit.

FIG. 5 is a diagram showing a flow of processing in a main control unit.

FIG. 6 is a diagram for explaining a control example of meandering suppression according to the embodiment of the present invention.

FIG. 7 is a diagram showing an example of actual results of meandering suppression;
(A) is a comparative example, and (b) is a result based on the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Skin pass mill 2, 3 Bridle roll 4 Rolled plate 5a, 5b Work roll 6a, 6b Backup roll 7a, 7b Hydraulic pressure reduction cylinder 8a, 8b Load cell 9 Controller 11 Meander detector 12 Main control part 13 Constant pressure reduction control part 14 Localization Roll-down control unit 15 Roll gap determination unit 15A Roll gap information storage unit 15B Roll gap selection unit 16A First roll relation information 16B Second roll relation information 16C Third roll relation information 17 Roll gap selection information 18A First threshold value 18B Second Threshold

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-24515 (JP, A) JP-A-3-216208 (JP, A) JP-A 8-39122 (JP, A) JP-A 63-215 63517 (JP, A) JP-A-57-94413 (JP, A) JP-B-52-29977 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 37/68

Claims (2)

(57) [Claims] 1. A meandering control method by a rolling mill which can select a constant pressure reduction control for controlling a target rolling load by each of a reduction device on an operation side and a drive side and a localization reduction control for controlling a roll gap to a predetermined value. A method of switching to the localization reduction control when the meandering amount of the rolled plate exceeds a predetermined threshold, and returning to the constant pressure reduction control when the meandering amount is within the predetermined threshold. A meandering suppression method in a rolling mill, wherein a moving average of the roll gap during the constant pressure reduction control is used as the roll gap. 2. A meandering control method for a rolling mill which can select a constant pressure reduction control for controlling a target rolling load by each of a reduction device on an operation side and a drive side and a localization reduction control for controlling a roll gap to a predetermined value. A method of switching to the localization reduction control when the meandering amount of the rolled plate exceeds a predetermined threshold, and returning to the constant pressure reduction control when the meandering amount is within the predetermined threshold. As the roll gap, the moving average of the roll gap during the constant pressure reduction control, and then set the priority to select the roll gap when switching from the localization reduction control to the constant pressure reduction control earlier in order to set a higher priority. A meandering suppressing method in a rolling mill, wherein a gap is selected and used.