JP3506098B2 - Shape control method and apparatus in sheet rolling - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a case where a single base material is rolled into a plurality of dimensions having different plate thicknesses and / or plate widths (plate thickness, plate width, plate crown, etc.) and different base materials having different components. TECHNICAL FIELD The present invention relates to a plate shape control method and a shape control device for changing rolling conditions for the purpose of changing dimensions (hereinafter referred to as running dimension changes) during rolling, such as when joining and continuously rolling.

[0002]

2. Description of the Related Art For the purpose of continuous process and improvement of productivity, development of so-called running dimension change technology for changing material dimensions (sheet thickness, sheet width, sheet crown, etc.) during rolling The cold rolling mill has already been implemented in many plants. Further, in recent years, the change in running dimension has been applied to hot rolling mills due to the progress of various peripheral technologies.

There are the following four cases as the cases where the running dimension change is carried out. (1) When manufacturing multiple products with different board thickness from the base material of the same component, (2) When manufacturing multiple products with different board width from the base material of the same component, (3) Base material of the same component When manufacturing multiple products with different strip widths and thicknesses from (4) When joining base materials with different components and continuously rolling. This may be the case when the sizes of the base materials to be joined are the same or different.

The change in running dimension is performed during rolling by means for changing the plate thickness, plate width, etc. provided on the rolling mill and plate shape changing means (for example, roll bend means, roll cross means, work roll shift means). It is performed by suddenly changing the rolling conditions. Therefore, depending on the control of the plate shape changing means, the plate shape of the rolled material deteriorates,
There is a problem that the area of defective shape extends more than necessary in the rolling direction.

As a conventional technique for preventing the deterioration of the plate shape, for example, there are those disclosed in Japanese Patent Laid-Open Nos. 62-57704 and 4-351213. In this Japanese Patent Laid-Open No. 62-57704, in the case of connecting materials having different plate thicknesses or plate widths, or both plate thicknesses and plate widths and continuously rolling, the rolling in the width direction between a rolling plate and a work roll is performed. A mechanical plate model formula that shows the relationship between the plate thickness distribution in the width direction and rolling conditions when the load is uniform is set in advance, and this mechanical plate crown model formula, or a calculation formula that further simplifies and / or modifies it Calculate the operation amount of the plate shape changing means in the material joint part and its vicinity using, and control the shape of the rolled plate at a predetermined timing based on this calculated value, roll bend force, roll shift force, shift A rolling mill using a roll as the plate shape changing means is disclosed as an example.

Further, in the above-mentioned Japanese Patent Laid-Open No. 4-351213, a rolling plate using a roll bending force and a roll cross angle of a work roll as plate shape changing means when many types of coils are connected and continuously rolled. Is disclosed. Specifically, as shown in FIG. 2, the control of the roll cross angle having a slow operation speed is started toward the target value of the cross angle of the trailing material prior to the start of the plate thickness change, and
The roll bend force is adjusted so as to compensate for this movement of the cross angle, and then the roll bend force is sequentially changed in synchronization with the plate thickness change to match the plate thickness change.At the end of the change of the cross angle, the roll cross force is changed. The corner and roll bend forces are controlled to the set values for the trailing material.

[0007]

In any of the above methods, before the sheet thickness change point reaches the rolling stand,
The shape control amount for the trailing material is predicted, and the operation amount of the shape control device is determined based on the control amount. Therefore, when the target mechanical plate crown at the tip of the trailing material predicted in advance matches the actual mechanical plate crown, the shape of the material after rolling is good. However, in practice, the actual rolling load may fluctuate due to the prediction error of the rolled material temperature, the prediction error of the rolling material deformation resistance, the actual plate thickness variation, etc. There may be a large difference between the mechanical plate crown and the actual mechanical plate crown.
In such a case, sufficient shape control cannot be achieved, inappropriate shape fluctuations occur in the material after rolling, and if the shape fluctuations are large, plate breakage will occur and hinder rolling of the rolled material. There was a problem.

The above problem is caused by the fact that the target mechanical plate crown is not set during the change of the running dimension, and since the target is not set, the error of the mechanical plate crown during the changing of the running dimension is momentarily changed. It was not possible to evaluate, let alone operate the plate shape changing means to correct the above error.

In order to improve the yield, the dimension change is generally performed at the same point of the rolled material in a plurality of rolling stands in order to increase the yield during running. Therefore, the inlet side dimension and the outlet side dimension of each rolling stand are changed at the same time. There is a complicated phenomenon happening.

Conventionally, with respect to a dimension change in which such a complicated phenomenon occurs, it is difficult to predict the mechanical plate crown during the dimension change during running with an accuracy that is practically satisfactory with a simplified model. In addition, since the calculation function power is insufficient for using a complicated model, the operation amount of the plate shape changing means before and after the change of the running dimension is obtained as in the above-mentioned conventional technique. However, it was not possible to set the target mechanical plate crown during the change in running dimensions.

Conventionally, in hot finish rolling,
Since only steel plates with a plate thickness of 1.2 mm or more were rolled, the conventional method does not actually correct the shape defect during the dimension change from the preceding material to the following material (during the change of the running plate thickness). There were no operational problems. However, in the continuous hot finish rolling that the inventors put into practical use for the first time in the world, the plate thickness was 0.8 mm.
When the hot finish rolling up to the above has been carried out, new problems such as breakage of the steel plate have occurred unless the control for preventing the defective shape is continued even during the change of the running plate thickness.

A conventional technique for controlling the target mechanical plate crown during rolling so as to match the actual mechanical plate crown is, for example, Japanese Patent Laid-Open No. 59-6411.
There is a method disclosed in Japanese Patent No. In the technique described in this publication, the shape control amount by the plate shape control means is changed in response to the fluctuation of the rolling load, which is the main fluctuation factor of the mechanical plate crown.

However, in the method disclosed in Japanese Patent Laid-Open No. 59-64111, the target mechanical plate crown during rolling and the actual mechanical plate crown are maintained so that the same target mechanical plate crown is maintained in a single material. This is a control method that matches the plate crown, and it was not necessary to change the target mechanical plate crown. However, in the case where materials with multiple dimensions are continuously rolled as described above, it is necessary to positively change the target mechanical plate crown of the preceding material and the following material during the continuous rolling, which results in stable operation. Although it is difficult to obtain the desired plate shape, Japanese Patent Application Laid-Open No. 59-64111 does not disclose any method for changing the target mechanical plate crown, so that it is difficult to apply it to the change in running dimension. Met.

[0014]

[Means for Solving the Problems] The inventors have obtained a target mechanical plate crown during the change of the running dimension, which has not been considered in the past, and the error between the actual mechanical plate crown and the target mechanical plate crown is obtained momentarily. This led to the idea of operating the plate shape changing means according to the error. That is, using the target mechanical plate crown of the preceding material and the target mechanical plate crown of the following material,
Calculate the target mechanical plate crown during the change in running dimension from the preceding material to the following material. Specifically, a shape control method characterized by setting as an arbitrary function connecting the mechanical plate crown setting value of the preceding material and the mechanical plate crown setting value of the following material, a straight line as an arbitrary function, Curves and other suitable functions can be used.

It is an object of the present invention to propose a shape control method in plate rolling that can obtain a stable plate shape even when the plate size is changed significantly during rolling. To do.

According to the present invention, the target mechanical plate crown set value before and after the plate dimension change is used for continuously rolling the rolled material by the rolling mill having the plate shape changing means capable of changing the mechanical plate crown. Based on the target mechanical plate crown set value before and after the plate dimension change, the target mechanical plate crown set value during the running dimension change is based on the target mechanical plate crown set value during the running dimension change rolling. It is set in advance before starting the running dimension change, and the plate shape changing means is operated so that the actual mechanical plate crown during the running dimension change becomes equal to the target mechanical plate crown during the running dimension change. It is a characteristic shape control method in strip rolling.

Further, according to the present invention, when the rolled material is a plurality of joined materials and the sheet size changing means is operated based on the target mechanical plate crown set values of the preceding material and the following material, the rolling dimension changing rolling is performed. , The target mechanical plate crown setting value during the running dimension change is set in advance before starting the running dimension change based on the target mechanical plate crown setting values of the preceding material and the following material, and In the shape control method, the shape changing means is operated so that the actual mechanical plate crown becomes equal to the target mechanical plate crown during the change of the running dimension.

Further, according to the present invention, the rolled material is one sheet material having different sheet thickness and / or sheet width in the rolling direction, and the sheet material is set based on the target mechanical sheet crown set values before and after the sheet dimension change. During rolling dimension change rolling that operates the shape changing means, the target mechanical plate crown setting value during the running dimension change is based on the target mechanical plate crown setting value before and after the plate dimension change. It is characterized in that it is set before starting the dimension change, and the plate shape changing means is operated so that the actual mechanical plate crown during the running dimension change becomes equal to the target mechanical plate crown during the running dimension change. This is a shape control method.

Further, according to the present invention, the plate shape changing means is provided for the purpose of changing the running dimension in the process of continuously rolling the preceding material and the following material connected thereto, or in the rolling process of one coil. This is a device that operates during running, and operates the plate shape changing means during the running dimension change based on the target mechanical plate crown set value before and after the plate dimension change before starting the running dimension change. The set amount calculation device that sets the amount and the target mechanical plate crown during the running dimension change based on the target mechanical plate crown setting value before and after the running dimension change, and the running dimension change A shape control device for plate rolling, comprising: a plate shape changing means correction amount calculating device for correcting the operation amount of the plate shape changing means in accordance with a difference from the actual mechanical plate crown.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described more specifically by taking a rolling mill having roll bend means and roll cross means as an example of plate shape control means.

When the mechanical plate crown is arranged by factors such as rolling load, roll bending force, roll cross angle and roll crown, it can be expressed as the sum of the respective factors as shown in the following formula (1). Ch = funcCP (P) + funcCB (B) + funcCC (C) + funcCW (C w) ...... (1) Note that in the above equation, Ch: mechanical strip crown, FuncCP: rolling load components of the mechanical strip crown, FuncCB: Mechanical plate roll bend force component of the crown, funcCC: roll cross angle component of the mechanical strip crown, funcCW: roll crown components of the mechanical strip crown P: rolling load, B: roll bend force, C: roll cross angle, C _w: roll crown is there. The actual mechanical plate crown during the running dimension change is also expressed by the above formula.

Further, when the target mechanical plate crown during the running dimension change is Ch _FGC , the target rolling load is P _FGC , the target roll bend force set value is B _FGC , and the target roll cross angle is C _FGC , the following (2) It becomes like a formula. Ch _FGC = funcCP (P _FGC ) + func CB (B _FGC ) + func CC (C _FGC ) + func CW (C _w ) ... (2)

Therefore, the mechanical plate crown error ΔCh that occurs during the change of the running dimension is expressed by the following equation (3). ΔCh = Ch−Ch _FGC = funcCP (P−P _FGC ) + func CB (B−B _FGC ) + func CC (C−C _FGC ) ... (3)

Here, the roll bend force during the running dimension change is adjusted to the target roll bend force setting value B _FGC, and the roll cross angle during the running dimension change is set to the target roll cross angle C _FGC.
According to Fig. 2, when operating toward each trailing material set value according to Fig. 2, the mechanical plate crown error ΔCh that occurs during the above-mentioned running dimension change is calculated by the following formula (4). It becomes the same as the mechanical plate crown component. ΔCh ＝ funcCP (P−P _FGC ) …… (4)

Therefore, if this rolling load error is detected while the running dimension is changed and the roll bend force is further adjusted to eliminate the rolling load error, the shape caused by the mechanical plate crown error during the running dimension changing The fluctuation can be suppressed.

The control of the roll bending force for eliminating the rolling load error can be performed as follows.
Usually, the influence of the roll bend force and the rolling load on the mechanical plate crown is often approximated as a linear function as expressed by the following equation (5). ΔCh = kP × (P−P _set ) + kB × (B−B _set ) (5) where kP, kB: influence coefficient P _set : rolling load reference value B _set : roll bending force Standard value

Therefore, the roll bending force ΔB for suppressing the mechanical plate crown error due to the rolling load error obtained by the equation (4) can be given by the following equation (6). ΔB = k × (P−P _FGC ) (6) Here, k: a value calculated by kP and kB in the above equation (5)

It should be noted that the target rolling load P _FGC during the running dimension change
May be calculated based on conditions such as rolling material hardness, inlet side plate thickness, and outlet side plate thickness while changing the running dimension, but the rolling load setting value of the preceding material and rolling load setting of the following material are set. The values may be calculated by connecting them with an arbitrary function. Straight lines, curves,
Other suitable functions can be used. If the running dimension change time is short, such as within a few times the roll bending force response, such as 1 second, the rolling load set value for the preceding material and the rolling load set value for the following material should be linear. You may calculate by connecting.

The shape control method according to the present invention comprises: (1) continuous formation of a material obtained by joining the trailing end of the preceding material conveyed first and the leading end of the following material conveyed subsequently to the preceding material. It can be applied to both rolling and (2) rolling of one material whose plate shape is changed during rolling.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 and 3 by taking a rolling mill equipped with a roll bend force control device and a roll cross angle control device as a plate shape changing means as an example.

FIG. 1 is an explanatory view of a control method of the present invention, in which 1 is a rolled material, 2 is a work roll of a rolling mill, and 4 is a backup roll of the rolling mill. When the running dimension is changed in this rolling mill, the target mechanical plate crown set value is set in advance based on the set value of the target mechanical plate crown of the rolled material before and after the dimension change before rolling.

Therefore, the set amount calculation device 40 calculates a target mechanical plate crown according to the trailing material, and the set amount calculation device 40 is calculated based on this target mechanical plate crown.
Sends the roll bend force setting amount changing device 22 and the roll cross angle setting amount changing device 32 the roll bend force setting value and the roll cross angle setting value corresponding to the trailing material, respectively. Incidentally, the calculation of the target mechanical plate crown according to the rolled material in the set amount calculation device 40, for example, the entrance side plate crown, the exit side plate crown target value, the exit side plate crown target value in the rolling stand, the control capability of the plate shape changing means, etc. It is decided based on.

On the other hand, the setting change timing instruction device 50 is
The position of the change point of the mechanical plate crown is grasped by a conventionally known means, and at a predetermined timing for changing the running dimension during rolling, from the setting change timing instruction device 50, the roll bend force setting amount changing device 22 and the roll cross. The change timing of each set amount of the roll bend force set value and the roll cross angle set value is output to the angle set amount changing device 32.

At the same time, the plate shape changing means is operated so that the actual mechanical plate crown during the change in running dimension is equal to the preset target mechanical plate crown during changing the running dimension. Therefore, in the roll bend force correction amount calculation device 24, the setting change timing instruction device 50
Using the rolling information transmitted from the set amount calculation device 40 together with the running dimension change start signal transmitted from, the target rolling load during the running dimension change is calculated moment by moment, and the load detector 10
According to the difference between the rolling load actual value calculated using the actual roll bending force value detected from the unillustrated roll bending force actual value and the actual load value detected by The roll bend force correction amount is calculated by.

The roll bend force setting amount determined by the roll bend force setting amount changing device 22 and the roll bend force correction amount determined by the roll bend force correction amount calculating device 24 are added by the adder 60, By setting the roll bend force to the roll bend force control device 20, the roll bend force during the running dimension change can be changed moment by moment.

The plate shape control method according to the present invention is shown in FIG. 3 in comparison with the conventional method. In FIG. 3, the rolling load, the roll cross angle, the roll bending force, the additional roll bending force, and the time series change of the material shape in the case of rolling a material whose plate thickness changes during rolling are shown in FIG. )) And the method of the present invention ((b) of the same figure).

In the conventional method, the roll cloth and the roll bend are operated toward the roll cross angle set value and the roll bend force set value of the trailing material according to a predetermined pattern before starting the change of the running plate thickness. Since there is no target mechanical plate crown that is the criterion for error, it is not possible to deal with the mechanical plate crown error that occurs due to the rolling load error while changing the running plate thickness, so add roll bend force before changing the running plate thickness. After holding, and after changing the running plate thickness, the additional roll bend force is corrected again based on the mechanical plate crown error. Therefore, in the section where the added roll bend force is held, the roll bend force control according to the rolling load error cannot be performed, and as shown in FIG. 3 (a), for example, due to the rolling load error (mechanical plate crown error), Defects such as ear extensions were occurring.

On the other hand, in the method of the present invention, since the additive roll bending force is applied every moment in accordance with the above-mentioned rolling load prediction error, stable rolling of the rolled material can be achieved with almost no change in shape. It is possible. Further, the plate does not break.

In this embodiment, the rolling mill using the roll vent force and the roll cross angle as the shape control means is shown as an example, but in the present invention, a rolling mill using only the roll vent force as the shape control means is used. Can also be applied. In addition to this, the shape control means may use a roll shift device, for example.

[0040]

According to the present invention, a change in plate shape due to a change in running dimension can be prevented by changing the setting of the shape control means, and a change in shape due to a prediction error during changing the running dimension can be prevented. By operating the shape control means so as to eliminate the prediction error, it has become possible to simultaneously prevent the shape change during the running dimension change.

[Brief description of drawings]

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

FIG. 2 is a diagram illustrating a conventional control method.

FIG. 3 is a diagram for explaining the effect of the present invention.

[Explanation of symbols]

1 rolled material 2 work rolls 10 load detector 20 Roll bend force control device 24 Roll Bend Force Correction Amount Calculation Device 30 roll cross angle control device 32 roll cross angle setting amount changing device 40 Setting amount calculation device 50 Setting change timing instruction device 60 adder

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiro Takebayashi 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Inside the Technical Research Laboratory, Kawasaki Steel Works (56) Reference JP-A-7-24512 (JP, A) JP-A 6-179006 (JP, A) JP-A-8-206712 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21B 37/00-37/78

Claims (7)

(57) [Claims] 1. When rolling a rolled material continuously by a rolling mill having a plate shape changing means capable of changing a mechanical plate crown, based on target mechanical plate crown set values before and after plate size change In the rolling dimension change rolling in which the strip shape changing means is operated, the target mechanical plate crown set value during the running dimension change is
Based on the set values of the target mechanical plate crown before and after the plate dimension change, it is set in advance before starting the running dimension change, and the actual mechanical plate crown during the running dimension change is A shape control method in plate rolling, characterized in that the plate shape changing means is operated so as to be equal to a target mechanical plate crown. 2. The rolling dimension change rolling according to claim 1, wherein the rolled material is a plurality of joined materials, and the plate shape changing means is operated based on the target mechanical plate crown set values of the preceding material and the following material. At, the target mechanical plate crown setting value during the running dimension change is
The mechanical plate crown is set in advance before starting the running dimension change based on the set values of the target mechanical plate crown of the preceding and following materials, and the actual mechanical plate crown during the running dimension change is the target mechanical plate during the running dimension change. A shape control method characterized in that the plate shape changing means is operated so as to be equal to a crown. 3. The rolled material according to claim 1, wherein the rolled material is one sheet material having a different plate thickness and / or plate width in the rolling direction, and based on the target mechanical plate crown set value before the plate dimension change and after the plate dimension change. In the rolling dimension change rolling that operates the plate shape changing means, set the target mechanical plate crown setting value during the running dimension change,
Based on the set values of the target mechanical plate crown before and after the plate dimension change, it is set in advance before starting the running dimension change, and the actual mechanical plate crown during the running dimension change is A shape control method characterized in that the plate shape changing means is operated so as to be equal to a target mechanical plate crown. 4. The shape control method according to claim 1, wherein a target mechanical plate crown set value Ch _FGC during the running dimension change is obtained from the following equation. Ch _FGC = funcCP (P _FGC ) + funcCB (B _FGC ) + funcCC
(C _FGC ) + func CW (C _w ) func CP (P _FGC ): Function formula of rolling load of mechanical plate crown with target rolling load (P _FGC ) as variable, funcCB (B _FGC ): Target roll bending force set value (B _FGC) function expression of mechanical plate crown as a variable, funcCC (C _FGC): function expression of the roll cross angle of the mechanical strip crown the target roll cross angle (C _FGC) as a variable, funcCW (C _w): roll crown A functional expression of a roll crown of a mechanical plate crown having (C _w ) as a variable, 5. The plate shape changing means for making the actual mechanical plate crown during the running dimension change equal to the target mechanical plate crown during the running dimension change according to any one of claims 1 to 3. A shape control method, wherein an error between a target rolling load and an actual rolling load is detected during a change in running dimension, and a roll bending force is operated so as to minimize this error. 6. The target rolling load value during changing of the running distance dimension as defined in claim 5, as a function of connecting the rolling load setting value before changing the running distance dimension and the rolling load setting value after changing the running distance dimension. A shape control method characterized by setting. 7. The plate shape changing means is provided for the purpose of changing the running dimension during the process of continuously rolling the preceding material and the following material connected thereto or the rolling process of one coil. It is a device to be operated, and sets the operation amount of the plate shape changing means during the running dimension change based on the target mechanical plate crown setting value before and after the plate dimension change before starting the running dimension change. The set amount calculation device and the target mechanical plate crown during the running dimension change based on the target mechanical plate crown setting value before and after the running dimension change, and the actual mechanical during the running dimension change A shape control device for plate rolling, comprising: a plate shape changing means correction amount computing device for correcting the operation amount of the plate shape changing means according to the difference from the plate crown.