JPS6011569B2 - Shape control method in 6-heavy rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shape control method in metal strip rolling, particularly in strip rolling using a six-layer rolling mill having an intermediate roll movable in the axial direction of the rolls and a work roll bending device.

An example of a shape control method when rolling a strip using a 6-layer rolling mill is the method disclosed in Japanese Patent Application Laid-open No. 49-27468.

In this method, before rolling, the initial values of the roll pending force and the axial position of the intermediate roll are set based on information necessary for shape control such as the steel type, width, thickness and reduction ratio of the next rolled material, tension, and roll diameter. This is a method in which the plate shape and plate width of the rolled material are detected during rolling, the roll pending force is corrected according to the plate shape, and the position of the intermediate roll in the ball direction is corrected according to fluctuations in the plate width. However, in such conventional shape control methods, if the steel type, dimensions, and rolling conditions of the rolled materials are the same, the initial setting values before rolling are always the same for the rolled materials that are rolled one after another, and There are disadvantages in that the shape control performance of the rolled material is not reflected in the setting values for the next rolled material, and the amount of correction of the roll pending force during rolling becomes large.Furthermore, the correction of the axial position of the intermediate roll is Since the modification operation based on the shape detection result is only performed by roll pending, the effect of shape modification is not perfect, and especially when ear waves and mid-elongation occur together, the shape cannot be completely corrected. The drawback was that no corrections could be made. The present invention provides a control method that eliminates the drawbacks of the shape control method in the conventional 6-height rolling mill as described above. In the shape control method for a 6-layer rolling mill, the rolling results including the detected value of the rolling machine outlet shape of the previously rolled material, the roll pending force measurement value in the previous rolling, and the intermediate roll axial position setting value, and the rolling results for the currently rolled material are used. The roll pending force and the rolling conditions including the planned value of the intermediate roll axial position are used to predict the roll exit shape of the rolled material using a predetermined relational expression, and the roll pending shape is optimized for this predicted shape. The present invention provides a shape control method for a six-fold rolling machine, characterized in that the force and the intermediate roll axial position are determined and used as initial setting values for the currently rolled material.

The present invention will be explained in detail below. First, to explain the detection of the shape of the rolled material on the exit side of the rolling machine, at least three shape detectors are provided on the exit side of the rolled material in the direction of the strip.
The shapes of the green parts on both sides and the central part of the strip are detected separately. Various known shape detectors can be used as shape detectors, but for example, if the shape of the strip is expressed by steepness, which is correlated with the tension of the strip, the steepness Q can be calculated from the shape detector output S using the following formula. is required. < Handling = K.ノ (s monkey;) 2-(most) 2-...

1, where K is a constant, Smin is the lowest value among the outputs of each shape detector, and the subscript x indicates the position in the strip width direction, with 1 and 3 at both side edges and 2 at the center.

If the steepness of one side twill of the strip is QM and the steepness of the other side twill is QM3, then the average steepness QM of both side edges is QM )2zu2. ．． -. ．． And the steepness QN of the central part of the strip is 6N=K.ノ (S longevity;) 2-(poison) 2... can be expressed as legs.

Next, how to obtain the initial setting values for the currently rolled material will be explained.

First, the rolling mill exit shape (steepness) of the rolled material is predicted as follows from the actual values of the previously rolled material and the planned values of the current rolling conditions. This prediction method is based on the actual steepness of the previously rolled material (using the average value in the strip length direction) and the rolling conditions of the currently rolled material (roll pending force B, intermediate roll opposite direction position 6, rolling load P, work roll A steepness prediction formula that linearly adds the changes in steepness based on changes in thermal crown ch, initial crown ci of the work roll, and input side shape cg of the rolled material is determined, and calculations are made using this prediction formula. It is. The prediction formula for steepness is as follows. QM = plex AB + old man △ s + force MA day stage ten △ C bass score △ Cg ten QN . ...(4)QN=sea△B
+ Meng △6 Jukan △P + Journal △Ch Juki ACi + Kago ACg JuQN . ...(5) Here Q
M is the predicted steepness of the side edges of the material rolled this time, QN is the predicted steepness of the center of the material rolled this time, and △B is the roll pending force (planned) of the current rolling with respect to the roll pending force (actual) of the previous rolling. ), △P is the change in the current rolling load (planned) with respect to the previous rolling load (actual), △8 is the axial position of the intermediate roll during the current rolling (planned) relative to the intermediate roll ball direction position during the previous rolling. , △ch is the change in the thermal crown (planned) during this rolling from the work roll thermal crown (actual) during the previous rolling, △
ci is the change in the initial crown of the current rolling with respect to the initial crown of the work roll during the previous rolling (determined by the rolling amount after the roll change), and △cg is the change in the shape of the currently rolled material at the entrance of the rolling machine and the previously rolled material. The change in the shape at the entrance of the rolling mill (determined by the steel type, dimensions, etc. of the rolled material), QN
is the actual steepness (average value) of the side edge of the previously rolled material, and QN is the amount showing the actual steepness (average value) and partial differential coefficient of the central portion of the previously rolled material (foundation,...,.aQu aQN-...old man)
Past Cape Nobu actual performance total acg'aB' This is an influence coefficient determined in advance.

The steepness of the currently rolled material is predicted using the formulas [4} and '5} above, and from this predicted steepness, the roll pending force and the axis uniformity of the intermediate roll for the currently rolled material that will give the best shape are calculated as follows: Find it like this.

Figure 1 shows the roll pending force at the time of the previous rolling. The shape of the rolled material (QM,
FIG. 12 is a diagram qualitatively showing how it changes with respect to QN). The horizontal axis of the diagram is the shape of the previously rolled material (QM,
QN), and each point b to e represents the change in roll pending force (increase or decrease) in this rolling and the change in the axial position of the intermediate roll (moving the intermediate roll outward or inward from the stand). This shows the coordinates of the shelf shape (N) in a certain combination state.At point b, the roll pending force is greatly increased, and when the intermediate roll is moved greatly toward the inside of the stand, at point c, the roll pending force is greatly increased. When the intermediate roll is moved greatly toward the outside of the stand, the roll pending force is greatly reduced at point d, and when the intermediate roll is moved greatly toward the inside of the stand, at point e, the roll pending force is greatly reduced and the intermediate roll is moved from the stand. Each pre-cervix when moved significantly outward. The coordinates of the shape (6M, 6N) are shown. As can be seen from Figure 1, the predicted shape of the material rolled this time varies greatly depending on the combination of the amount of change in the roll pending force and the amount of change in the same axial position of the intermediate roll compared to the previous rolling.
', 'When predicting the steepness of the rolled material using Equation 51, the amount of increase or decrease in the roll pending force and the amount of movement of the intermediate roll outward or inward from the stand were changed in small increments (for example, the roll pending force is 2000 k9 back, the amount of movement of the intermediate roll is every 1 cape), and the steep dust in the case of each combination of changes) Tei Takaminato ≦ Ashi Hōmineji Hōkaku, and Maisu Minato Mist Mark F. The following formula F: (union)
20K2(6N)2 ``“'''61 However, K2 is determined by a constant.

Then, the amount of change in the roll pending force (△B) and the amount of change in the axial position of the intermediate roll (△6) are determined so that the shape index F is at most 4, and these changes are calculated based on the actual results from the previous rolling. The value or the value added to the set value is used as the initial set value for the roll pending force and the axial displacement of the intermediate roll for the current rolling. Here, it is also possible to change the rolling load so that the shape index is within the target range, but in this case, if the rolling mill has multiple stands, the rolling load of the other stands is also changed to change the rolling force of each stand. Maintains proper load distribution. Next, embodiments of the present invention will be described.

FIG. 2 is a block diagram showing the configuration of a control system in an embodiment of the present invention. In the figure, 1 is a strip that is a material to be rolled (previously rolled material in the present invention), 2 is a winding roll, and 3 is a rolled material.
, 3' are backup rolls of the rolling mill, 4 and 4' are intermediate rolls, 5 and 5' are work rolls, 6 is a shape detector installed on the exit side of the rolling mill, 7 is a roll pending detector, and 8 is a work roll. a drive motor; 9 is a current detector for the motor 8;
10 is a rolling load detector, 11 is an amplifier circuit, 12 is a shape calculation circuit, 13 is a smoothing circuit, 14 is a thermal crown calculation circuit, 15 is a difference calculation circuit, 16 is an influence coefficient calculation circuit,
17 is a predicted shape calculation circuit, 18 is an optimal setting value calculation circuit,
19 is a rolling schedule calculation device, 20 is a load distribution setting machine, and the portion surrounded by a dashed line in the figure is a portion added to a normal rolling mill control device for implementing the present invention.
Three shape detectors 6 are arranged in the width direction of the strip 1, and the output from each detector is inputted to a shape calculation circuit 12 via an amplifier circuit 11. The shape calculation circuit 12 has the above-mentioned [
2} and [3} calculate the steepness of the west edge and the center of the strip. The smoothing circuit 13 calculates the average value of the steepness (QM, QN), the average value of the work roll pending force B, and the average value of the rolling load P over the entire length of one coil of the strip 1, respectively. The thermal crown calculation circuit 14 uses the current of the work roll drive motor 8 to calculate the thermal crown ch of the work roll at fixed time intervals (for example, every 0.0 flow) using the following equation. c.
h=(k31-c~)(1-ek4t)+ch. Here, 1 is the current, t is the sampling time, c~ is the thermal crown at the previous calculation, K3, k4 are the constant difference calculation circuit 1
5 is the work roll pending force B, rolling load P, thermal crown Ch, intermediate roll axial position 6 in the previous rolling obtained as above, and the work roll in the previous rolling stored in the rolling schedule calculation device 19. This time is temporarily calculated or set by the rolling schedule calculation device 19 based on a standard formula or table based on the initial crown ci, the rolling mill entrance shape cg that depends on the steel type dimensions of the rolled material, etc., and the steel type dimensions of the currently rolled material, etc. Work roll pending force B on the rolled material, intermediate roll axial position 6, rolling load P, work roll initial crown ci, thermal crown ch, difference from rolling mill entry side shape cg (△B, △8, △P, △ci, △
ch, Δcg). The influence coefficient calculation circuit 16 is a circuit that calculates each influence coefficient necessary for the calculation of the above-mentioned equations {5} and 16. It calculates each influence coefficient calculation formula (rolling Based on the information on the scheduled rolling conditions of the currently rolled material from the rolling schedule calculation device 19, the influence coefficient for determining the current rolling conditions (Sagi, Monsei, etc.) Calculate the ticket price).

The willow shape calculation circuit 17 predicts the steepness of both side edges and the center of the currently rolled material using the steepness prediction formula shown in equations t4) and '5}.

Here {41. When calculating the predicted steepness using the formula '5-, the predicted shape calculation circuit 17 works together with the optimum setting calculation circuit 18, and calculates the change in roll pending force in the formula '41, '5} △ B and the change △8 in the axial position of the intermediate roll are input from the difference calculation circuit 15 as △B and △
Calculations will be made for cases in which the value of 6 is increased or decreased by a certain amount. The optimum setting value calculation circuit 18 calculates the shape index F using the formula each time the predicted shape calculation circuit 17 calculates the predicted shape, and calculates the minimum shape index F within the predetermined variable range of the roll pending force and the intermediate roll axial position. Find the value when this shape index value is the minimum. Changes in the roll bending force are input to a roll pending force control device (not shown), and the amount of change in the axial position of the intermediate roll when the shape index value is the minimum is input to an intermediate roll movement control device (not shown). The roll pending control device sets the roll bending force for the currently rolled material based on the value obtained by adding the roll pending force change amount to the average value of the roll pending force in the previous rolling, which is input through a path not shown, and controls the intermediate roll. The movement control device changes the setting of the intermediate roll axial position of the previously rolled material for the current rolling according to the amount of change in the intermediate roll axial position. Although not shown, the roll pending force and intermediate roll axial position for the currently rolled material set as described above are also input to the rolling schedule calculation device. Furthermore, although the explanation has been omitted above, when calculating the predicted shape in the predicted shape calculation circuit 17, the rolling load may also be increased or decreased by a certain amount, and when changing the set value of the rolling load, the As mentioned above, consider the load distribution of other stands in a multi-stand. Figure 3 shows the intermediate elongated shape when the shape control method of the present invention is implemented in a six-layer rolling mill, which is the final stand of a cold tandem rolling mill. 49-27468), the head shape was better, the time required to reach the target shape was shorter, and the shape accuracy was improved.

As described above, the shape control method of the present invention uses the results of the previously rolled material to determine the shape of the material to be rolled this time in strip rolling using a 6-layer rolling mill having an intermediate roll movable in the roll axis direction and a work roll pending device. Since the position of the roll in the ball direction and the setting value of work roll pending are determined, the optimum setting value can be determined based on the latest rolling results, and the precision of shape control is greatly improved compared to the conventional method.

[Brief Description of the Drawings] Fig. 1 is a diagram for explaining the shape change of a rolled material when the roll pending force and the position of the intermediate roll in the crane direction are changed, and Fig. 2 is a diagram for explaining the shape change of the rolled material when the roll pending force and the position of the intermediate roll in the crane direction are changed. FIG. 3 is a block diagram showing the configuration of the control system, and a graph showing a comparison between the conventional method and the method of the present invention regarding the steepness of the middle extension. 1 is a strip, 2 is a winding roll, 3, 3' is a backup roll, 4, 4' is an intermediate roll, 5, 5' is a work roll, 6 is a shape detector, 7 is a roll pending force detector, 8 is a work roll drive motor, 9 is a current detector,
10 is a rolling load detector, 11 is an amplifier circuit, 12 is a shape detection circuit, 13 is a smoothing circuit, 14 is a thermal crown calculation circuit, 15 is a difference calculation circuit, 16 is an influence coefficient detection circuit,
17 is a predicted shape calculation circuit, 18 is an optimal setting value calculation circuit,
19 is a rolling schedule calculation device, and 20 is a load distribution setting device. Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] 1. In a shape control method for a six-layer rolling mill having an intermediate roll movable in the roll axis direction and a work roll bending device, the detected value of the shape of the previously rolled material on the exit side of the rolling mill and the measured value of the roll bending force in the previous rolling are The rolling machine exit shape of the currently rolled material is predicted using the rolling results including the intermediate roll axial position setting value and the rolling conditions including the roll bending force for the currently rolled material and the planned value of the intermediate roll axial position. A 6-layer rolling mill characterized in that the roll bending force and intermediate roll axial position at which the predicted shape is the best are determined by predicting using a predetermined relational expression, and these are used as initial setting values for the currently rolled material. shape control method.