JP2004216458A - Apparatus for determining manipulated variable set value of sheet crown/shape in rolling mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine the set values of the manipulated variables of the crown/shape in rolling mills in such a manner that a desired sheet crown and shape can be obtained. <P>SOLUTION: The apparatus is equipped with a means for determining the manipulated variable of an actuator for controlling the crown shape by each of respective stands in continuous rolling and multipass rolling. The target crowns of the middle stands are determined by taking the permissible ranges of the sheet shape of the middle stands and the upper and lower limit values of the manipulated variables of the actuators for crown/shape control into consideration. The manipulated variables of the actuators for crown/shape control are then determined. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention controls the shape of the rolled material in the properties of the steel sheet in hot rolling, and particularly in continuous rolling or multi-pass rolling, determines the operation amount of the crown shape of each stand in a well-balanced manner, and sets the target crown and the target shape. The present invention relates to an apparatus and a method for determining a set value of a plate crown / shape operation amount for achieving the above.

  In recent years, rolling mills provided with various sheet crown / shape control devices have been put into practical use, and accurate physical models expressing the rolling phenomenon have been developed. However, in continuous rolling and multi-pass rolling, it is difficult to determine the target value of the plate crown of each stand or each pass, so that not only the ability of the rolling mill can be fully utilized but also an accurate model cannot be utilized.

  Generally, in controlling the crown and shape in hot rolling, the schedule for achieving the target crown of the final stand within the allowable range of the operation amount of the crown and shape control actuator and the allowable range of the shape is used. It is important to determine the operation amount of the actuator.

  At this time, as for the shape of the intermediate stand, for example, as disclosed in Patent Literature 1 and Patent Literature 2, a method in which a flat shape is obtained by rolling in a state in which the sheet crown ratio is as close as possible as possible. There is. At this time, when determining the target plate crown of each stand, conventionally, only the shape disturbance due to the change of the plate crown ratio is considered, and the upper and lower limits of the operation amount of the actuator are taken into consideration, as in Patent Document 1. Did not.

  That is, in Patent Document 1, the maximum / minimum sheet crown ratio of each stand that can be achieved based on each stand shape allowable range and the sheet crown shape control operation amount allowable range is calculated, and based on this, the target product sheet crown ratio is calculated. On the other hand, the target plate crown ratio of each stand is determined so that the change in the plate crown ratio between stands in the downstream stand is small (that is, the plate flatness between stands is small in the downstream stand). Based on this, the control amount of the crown shape control of each stand was determined.

  As methods for considering the upper and lower limits of the operation amount of the actuator, for example, Patent Literature 3 and Patent Literature 4 propose a method using a linear programming method.

  Also, in order to make the inter-stand shape as desired, the intermediate stand plate shape that cannot be recognized by the control model is input by the operator from the operator interface as upper and lower limit values of the shape correction operation amount by visual judgment by the operator, Patent Literature 5 discloses a method for determining an operation amount of an actuator.

  Another example is Patent Document 6 (unknown at the time of the first application). This is the same as the method of Patent Document 1 until the maximum / minimum plate crown ratio of each stand is calculated. However, in determining the target plate crown ratio of each stand, the balance of all stands is taken into consideration. Has been improved.

Japanese Patent Publication No. 3-33041 Japanese Patent Publication No. 3-72364 JP-A-1-181911 JP-A-1-254305 JP-A-1-245907 JP-A-6-134508

  However, in order to make the shape between stands as good as possible, in the conventional method of rolling so that the sheet crown ratio is as constant as possible, even if the sheet crown ratio is fixed, the shape does not actually become flat. There was a problem that there were many cases. Further, since the ear-extended shape is more stable in operation, the flat plate shape itself is a problem.

  Further, in the method of visually determining and inputting the upper and lower limits of the inter-stand shape by the operator's eyes, there is a problem that there is an individual difference between operators and the load on the operator.

  In addition, after calculating the maximum / minimum plate crown ratio of each stand, when determining the target plate crown of each stand, the method of determining by paying attention only to the shape without considering the upper and lower limits of the operation amount of the actuator is used. In some cases, a target plate crown that cannot be realized is determined due to the capability of the actuator. As a result, there is a problem that the target plate crown / shape cannot be obtained.

  Also, when calculating the target plate crown ratio of each stand, the target of the shape for each stand cannot be realized because the allowable range of each stand shape is not taken into account. For example, there is a problem that it is not possible to realize a commonly-used rolling method in which the upstream stand is shaped into a belly wave side and the downstream stand is rolled on an ear wave side.

  Further, in the method using the linear programming in consideration of the upper and lower limits of the actuator, a matrix operation is necessary and complicated due to the nature of the linear programming.

  The present invention has been made to solve the above-mentioned conventional problems, and provides an apparatus and a method for determining a set value of a sheet crown / shape operation amount in a rolling mill that can obtain a desired sheet crown and shape. Aim.

  The present invention provides a device for controlling the crown and shape of a sheet material by a rolling mill having a sheet crown / shape controlling actuator, which determines a set value of a crown / shape operation amount in a rolling mill. Rolling condition input means for inputting rolling conditions such as rolling conditions, maximum / minimum sheet crown ratio calculating means for receiving an output from the rolling condition input means, and calculating a maximum sheet crown ratio and a minimum sheet crown ratio; and Receiving the output from the sheet crown ratio calculating means, determining the target sheet crown ratio of each stand or each pass, and receiving the output of the target sheet crown ratio determining means, It is provided with a sheet crown / shape operation amount determining means for determining the sheet crown / shape operation amount, and within the maximum / minimum sheet crown ratio range of each stand. And, taking into account the range of the actuator operation amount, by determining a target strip crown of each stand sequentially toward the upstream stand from the target strip crown of the final stand, in which to achieve the above object.

  Further, the present invention achieves the above-mentioned object in the same manner by further comprising means for determining the allowable steepness upper / lower limit value and the target shape of each stand by a model formula in accordance with actual operating conditions. is there.

  The present invention also provides a method for controlling a crown and a shape of a sheet material by a rolling mill having a sheet crown / shape control actuator, and a method for determining a set value of a sheet crown / shape operation amount in a rolling mill. From the rolling conditions such as rolling load, the maximum sheet crown ratio and the minimum sheet crown ratio are calculated, and from the calculated maximum sheet crown ratio and minimum sheet crown ratio, within the range of the maximum and minimum sheet crown ratios of each stand, and Considering the range of the actuator operation amount, the target plate crown ratio of each stand or each pass is determined sequentially from the target plate crown of the final stand toward the upstream stand, and from the determined target plate crown ratio, each stand or The object has been achieved by determining the sheet crown and shape operation amount of each pass.

  According to the present invention, the maximum and minimum sheet crown ratios of each stand are obtained from material information such as sheet thickness given in advance, rolling load prediction values, and allowable upper and lower limits of the steepness of each stand.

  Thereafter, the target plate crown of each stand is sequentially determined from the target plate crown of the final stand toward the upstream stand within the maximum and minimum plate crown ratio ranges of each stand and within the range of the actuator operation amount. Therefore, a feasible plate crown target value of each stand can be obtained.

  Further, according to the present invention, when the actual data of the operation is substituted into the shape control model, the allowable steepness upper and lower limit values of each stand are obtained, and the target shape of each stand is determined, the operator is required The shape between stands when the plate crown / shape control actuator is manually set and the plate is passed can be reproduced, and a shape suitable for actual operation can be realized.

  According to the present invention, a shape obtained by statistically processing a shape calculated by inputting actual operation data into a shape control model is set as a target shape, and a plate crown target of each stand is set from the target shape and the hardware capability of the actuator. In addition, there is an excellent effect that the target of the sheet crown can be achieved while obtaining a shape suitable for the actual operation.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an apparatus for determining a set value of a sheet crown / shape operation amount of a rolling mill including seven stands according to the present embodiment.

  In FIG. 1, 2 is an F1 stand, 4 is an F7 stand, 6 is a bender, 8 is a load detecting device, 10 is an allowable steepness determining device, and 12 is an operation amount determining device.

In the present embodiment, the plate crown / shape control actuator is a cross between a bender and a work roll, and FIG. 2 is a side view showing a roll cross. FIG. 3 is a plan view showing a roll cloth, and θ represents the cross angle. As shown in FIG. 2, the roll cross system of each stand is a pair of upper backup rolls (BUR) and upper work rolls (WR) arranged in parallel, and a lower backup roll (BUR) and a lower work roll (WR) arranged in parallel. As shown in FIG. 3, a so-called pair-cross method is used in which a pair of lines intersect at a required angle θ _i with a horizontal line perpendicular to the rolling direction.

  FIG. 4 is a flowchart showing the operation of the present embodiment. Hereinafter, the operation of the present embodiment will be described based on this. In step 100 of FIG. 4, calculation of the influence coefficient is performed, and in step 102, the allowable steepness is determined. This is performed in the allowable steepness determination device 10 of FIG.

The allowable steepness determination device 10 first determines each stand (from the material information such as plate thickness and plate width, the actual value of the plate crown / shape control actuator obtained from the bender 6, the actual load value obtained from the load detection device 8, and the like). influence coefficient of the stand No.i = 1~7) Ai, Bi, Ci, offset Di, transcription factor alpha _i, genetic factor beta _i, the shape change factor xi] _i, determined in advance.

  Next, the shape (steepness) of each stand (i = 1 to 7) is determined by the following equations (1) to (4).

^{Cri * = Ai · Pi + Bi} · P Bi + Ci · θ i 2 + Di ... (1)
^{_{Cri = α i · C ri *}} + β i · C ri-1 ... (2)
Δε _i = ξ _i (C _ri / hi−C _ri−1 / h _i−1 ) (3)
λ _i = sign (Δε _i ) · 2 / π√ | Δε _i | (4)

Here, Cri ^* is a mechanical crown, Pi is the rolling load, P _Bi vendor loads, theta _i is cross angle of the work rolls, C _ri the plate crown, hi is the thickness, [Delta] [epsilon] _i is the elongation difference, lambda _i is It is steep. Further, in particular C _r0 as sheet bar crown, h ₀ is given as a sheet bar thickness. The symbol sign (Δε _i ) indicates that the sign of + is used when Δε _i is positive, and that the sign is − when Δε _i is negative.

  FIG. 5 shows a shape obtained by inputting actual operation data into the shape control model. In FIG. 5, the position of each alphabetic character represents the actual data position. This is an example of a steepness target indicating the degree of ear extension and belly extension of the board on the exit side of the F4 stand. Here, a general material of 900 <board width ≦ 1200 mm is handled. The abscissa represents the product thickness, and the ordinate represents the shape (steepness) obtained by inputting actual operation data to the shape control model. In this example, the thinner the material, the more the ear extends on the control model. It is better to roll at (the steepness is on the positive side). The allowable steepness (upper limit and lower limit) is determined from the graph shown in FIG.

  Next, in Step 104 of FIG. 4, a plate crown ratio variable region is determined. When obtaining the maximum and minimum plate crown ratios of each stand, two broken lines indicating the upper limit and the lower limit of the graph of FIG. 5 are used as the shape allowable range. Then, a sheet crown ratio variable area is determined as an area between the curve indicating the maximum sheet crown ratio and the curve indicating the minimum sheet crown ratio as shown in the graph of FIG. This area is determined in consideration of the allowable steepness and the capability of the actuator (bender, work roll cross).

  Next, in step 106 of FIG. 4, when the target plate crown is outside the above-determined plate crown ratio variable region, the target plate crown is corrected.

  Next, at step 108, the target plate crown of each stand is determined while going back from the target plate crown of the last stand to the upstream stand.

  FIG. 6 is a graph comparing the conventional method and the method according to the present embodiment when determining the target plate crown of the upstream stand from the target plate crown of the last stand. Here, in both cases, the target shape of each stand has a steepness of 0 for easy comparison.

  In the example shown in FIG. 6, in the conventional method (constant rear plate crown ratio), the F6 stand is still good when going back from the target plate crown in the final F7 stand, but when the target plate crown of the F5 stand is determined, the actuator is not used. Since the operation amount is out of the allowable range, the target plate crown which cannot be realized due to the performance of the actuator is set.

  On the other hand, in the method of the present embodiment, a target plate crown that can be realized by considering both the allowable steepness and the capability of the actuator can be set. Therefore, the accuracy of the plate crown is better than that of the conventional method.

  Finally, in step 110 of FIG. 4, the actuator set value is determined. The operations in steps 104 to 110 are all performed by the operation amount determination device 12 in FIG. The set value of the cross between the bender and the work roll is finally determined by the operation amount determining device 12, and the plate crown / shape control for setting the value to the bender and the cross of each stand is performed.

Explanatory view showing a schematic configuration of a device for determining a set value of a sheet crown / shape operation amount of a rolling mill including seven stands according to a first embodiment. Side view showing work roll cloth A plan view showing the work roll cloth Flowchart showing the operation of the first embodiment Diagram showing allowable steepness Diagram showing setting of target plate crown at each stand

Explanation of reference numerals

2 F1 stand 4 F7 stand 6 Bender 8 Load detection device 10 Allowable steepness determination device 12 Operating amount determination device

Claims (3)

By a rolling mill having a sheet crown / shape control actuator, a crown and a shape of a sheet material are controlled, and in a device for determining a sheet crown / shape operation amount set value in a rolling mill,
Rolling condition input means for inputting rolling conditions such as plate thickness, plate width, rolling load,
Maximum / minimum sheet crown ratio calculation means for receiving an output from the rolling condition input means and calculating a maximum sheet crown ratio and a minimum sheet crown ratio,
Target sheet crown ratio determining means for receiving an output from the maximum / minimum sheet crown ratio calculating means and determining a target sheet crown ratio for each stand or each pass,
A plate crown / shape operation amount determining unit that receives an output of the target plate crown ratio determining unit and determines a plate crown / shape operation amount of each stand or each pass,
The target plate crown of each stand is determined sequentially from the target plate crown of the final stand toward the upstream stand in consideration of the range of the actuator operation amount within the maximum / minimum plate crown ratio range of each stand. A device for determining a set value of a crown and shape operation amount in a rolling mill.   2. The sheet crown / shape operation in a rolling mill according to claim 1, further comprising means for determining an allowable steepness upper / lower limit value and a target shape of each stand by a model formula in accordance with actual operating conditions. A device for determining the quantity set value. By a rolling mill having a sheet crown and shape control actuator, to control the crown and shape of the sheet material, in the method of determining the set value of the sheet crown and shape operation amount in the rolling mill,
Calculate the maximum sheet crown ratio and the minimum sheet crown ratio from rolling conditions such as sheet thickness, sheet width, and rolling load,
From the calculated maximum sheet crown ratio and minimum sheet crown ratio, within the maximum / minimum sheet crown ratio range of each stand and in consideration of the range of actuator operation amount, sequentially move from the target sheet crown of the final stand to the upstream stand. Toward, determine the target plate crown ratio of each stand or each pass,
A method for determining a sheet crown / shape operation amount set value in a rolling mill, wherein the sheet crown / shape operation amount of each stand or each pass is determined from the determined target sheet crown ratio.

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