JPH02258108A - Method and apparatus for controlling shape of rolling mill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the invention] (Industrial application field) The present invention provides at least a reduction device as an actuator;
The present invention relates to a shape control method and apparatus in a rolling mill, in which a strip is passed through a stand having an actuator including a bender and a roll coolant device divided in the roll width direction, and is controlled so that the strip has a predetermined flatness and plate crown.

In this specification, the term "shape control" will be used to include both flatness control and plate crown control.

(Prior art) Regarding the control technology of the exit side plate crown of a continuous rolling mill, for example, Tsuji et al., “Development of high-precision plate thickness and crown control technology in hot rolling” (“Tetsu to Hagane” 74th year (1988)) No. 3, pages 77-84) is known. As stated in the section ``3.2 Crown shape control technology'' on page 81 of this document, conventional plate crown control involves ``initial setting of the roll cross angle and roll bender force in advance prior to rolling.'' This is implemented by a "crown shape control system" consisting of a setting function and a dynamic control function that operates only the roll bender during rolling.

(Problems to be Solved by the Invention) In the conventional crown control technology described above, it is not clear which stand should be controlled and how to control the plate crown in a continuous rolling mill. The handling of plate flatness associated with control was also not clear.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shape control method and apparatus in a rolling mill that can control the plate crown to a desired value without causing defects in plate flatness.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, in the shape control in the rolling mill of the present invention, the deviation between the set value and the measured value of the plate crown and the deviation of each actuator within the tolerance range of flatness. The plate crown is controlled by determining the control setting values for each actuator except for the roll crand device so as to minimize the sum of squares of the difference from the plate crown effect over the entire plate width, and the residual error of the plate crown is determined. It is characterized by being controlled by a roll coolant device.

(Function) Within the allowable range of flatness, determine the set values of the actuators other than the roll coolant device so that the sum of the squares of the deviation between the set value and the measured value of the plate crown over the entire plate width is minimized, The residual error of the plate crown is controlled by a roll coolant device divided in the width direction of the plate, and the plate crown is controlled back to achieve the desired value without causing poor plate flatness. I can do it.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the shape control device according to the present invention,
FIG. 2 shows the arrangement of the rolls and actuators of one stand in a continuous rolling mill to which the shape control device of FIG. 1 is applied.

Although FIG. 1 shows a continuous rolling mill consisting of six stands arranged in tandem, the number of stands may be arbitrary.

In FIG. 2, a total of six work rolls 31 and 32, a pair of intermediate rolls 33 and 34, and a pair of backup rolls 35 and 36 sandwich the strip 20 to be rolled from both upper and lower sides. An example of a so-called six-high mill having six rolls is shown;
The number of rolls may be arbitrary, such as a four-stage mill. Naturally, depending on the number of stages in the mill, there may be intermediate rolls or no backup rolls.

Each actuator explained with reference to FIG. 1 is conceptually shown in FIG. 2 by the direction of its acting force, and the work roll bender (WRB) 37 and The upper and lower work roll shift devices (WR8) 38°39 move the upper and lower intermediate rolls 33
．． For 34, upper and lower intermediate roll bender (IMRB
) 40°41 and upper and lower intermediate roll shift devices (1M
R8) 42, 43 are further provided with a drive side rolling down device 44 and a work side rolling down device 45 for the upper and lower backup rolls 35 and 36, respectively. The difference in the amount of reduction by the side reduction devices 44 and 45 is the leveling amount, and the side reduction devices 44 and 45 are collectively referred to as a leveling device (LEV) 46 in FIG. A roll coolant device (RCL) having multiple nostles is also provided to cool each roll by dividing it into multiple positions in the width direction.
Illustration is omitted.

The continuous rolling mill shown in Fig. 1 consists of 6 stands 1, 1, and 6 stands arranged in tandem.
It consists of 2, 3, 4, 5.6. A flatness needle 7 and a crown meter 8 are arranged on the exit side of the final stand 6. The crown gauge 8 measures the thickness of the strip 20 by dividing it into N parts in the width direction. A setting calculation means 9 is provided for setting and calculating target values for the flatness and crown of the strip 20 obtained from the exit side of the final stand 6 based on the steel type, plate thickness, plate width, etc. in each case. The setting calculation means 9 calculates the amount of leveling, work roll bender force, and intermediate leveling for each stand to obtain a predetermined flatness and crown before passing the strip 20 or changing the steel type, plate thickness, plate width, etc. The roll bender force, work roll shift amount, intermediate roll shift amount, and roll crimp amount as width direction distribution are calculated and set as initial target values to the actuators 11 to 6 of each stand via adders 21 to 26, respectively. do. Here actuator 1
1 to 16 each have a built-in actuator control device.

The difference between the flatness of the strip 20 measured by the flatness needle 7 provided on the exit side of the final stand 6 and the target value set by the setting calculation means 9, that is, the flatness deviation, is determined by the adder 10, and the flatness deviation is determined by the adder 10. The flatness control means 17 calculates correction amounts for the target values of the leveling amount, work low bender force, intermediate roll bender force, work roll shift amount, intermediate roll shift amount, and roll coolant amount to zero, for each stand. As a result, the initial target value set by the setting calculation means 9 is corrected by the adder 26, and each of the corrected target values is applied to the actuator 16 of the final stand 6.

The difference between the plate crown measured by the crown meter 8 and the plate crown [1 standard value set by the setting calculation means 9, that is, the plate crown deviation, is determined by the adder 18,
Leveling amount for each stand 1, 2, 3, 4.5, work roll bending force, intermediate roll bending force, work roll shift amount, intermediate roll shift amount, and roll coolant amount for each stand other than the final stand that makes it zero The amount of correction for the target value is calculated by the crown control means 19, and the adders 21 to 25 add corrections to each target value set by the setting calculation means 9, and each of the corrected target values is used as the final stand. Each stand other than 1
There are ~5 actuators.

According to the above definition, the crown deviation Δc e,j obtained as the output of the adder 18 is 1? EP MEAS ΔC6,j=0[i,j-06,j...(3) (However, j=1.2...,N). The device shown in FIG. 1 has Δc calculated by equation (3).
A control operation is performed so that e and j become zero.

In the crown control means 19, the crown deviation Δc of equation (3)
Perform the following calculation using e and j as input.

Assuming the crown evaluation function of stand 5 to be J5, 11 to 1
given to 5.

Now, the control of the plate crown using the configuration described above will be described in detail below.

In the following description, it will be expressed as the exit side of each stand. Here, the suffix l represents the number of the stand when viewed in the flow direction of the strip 20, and the suffix j represents the division value in the width direction of the strip 20, that is, the position when viewed from the side edge end of the strip 20.

Now, the plate crown target value (the plate thickness of each j-divided portion in the plate width direction) which is the output of the setting calculation means 9 is assumed to be. However, j
is the number of the division section indicating the position in the width direction of the strip plate.

Also, the output of the crown meter 8 is assumed to be: This determines each target value of each actuator so that the thickness of each of the j division parts in the plate width direction, that is, the crown evaluation function J5 is minimized. Note that each symbol in equation (4) is defined as follows.

side crown ratio) ΔL5: Leveling amount ΔF of stand 5; Work roll bendy WB of stand 5, 5
ΔF Intermediate roll bending of stand 5 5 Guka ΔS: W of stand 5 W, 5 Crawl shift i-amount aS Influence coefficient W, 5 ΔS: Intermediate roll shift amount of stand 5 1.5 aS Influence coefficient 1 .5 For example, if the plate width is 2300+++n, and if the plate is divided at intervals of 50 mm in the width direction, then in equation (4), N=
It becomes 46. Equation (4) means that the sum of squares of the deviation between the plate Claran deviation and the amount controlling it is minimized over the entire plate width direction.

From equation (4), by setting a(ΔL5) a(ΔFWB, 5), the actuator values of stand 5 are leveling amount ΔL5, work roll pending force ΔF 1 intermediate roll force WB, 5 ending force ΔF1.5' Work roll shift unit ΔS
1 and the intermediate roll shift amount Δsl,5 are determined as W,5.

Generally, there are mechanical limits to the capabilities of actuators.

In other words, L　L　　　　　　　　li.

ΔL5≦ΔL5≦ΔL5 ・・Song・(1o)L
L ULΔFWB, 5≦Δ
FWB, 5≦ΔFWB, 5...-(II).

It is.

Here, the upper suffix LL indicates the lower limit value, and UL indicates the upper limit value.

If each value of each actuator determined by formulas (5) to (9) exceeds the range of formulas (10) to (14),
Let those lower limit values or upper limit values be each actuator value.

The actuator of the stand 5 determined by the above method is now: A change in the crown of any stand causes a change in flatness. If the crown change is small, no flatness change will occur, but if the crown change is large, the flatness will deteriorate, and in extreme cases, squeezing and other phenomena will occur, making rolling impossible.

Therefore, a flatness dead zone is defined.

FIG. 3 is a diagram showing a flatness dead zone with respect to crown change, and it is assumed that the range from point A to point B is the allowable range of crown change. Correspondingly, the allowable flatness change range is from point 0 to point D. For example, the flatness value of points C and D is 2.5% in terms of steepness. Note that the steepness is the value of the height of waves due to poor flatness, where L is the r1 pitch.

If D is exceeded, the linearity of each actuator on the right side of equation (20) is subtracted so that the flatness falls within the range of points C and D.

With the above steps, each actuator value can be determined. now,
These are again ΔL5. ΔF B, 5°ΔF1.5'
ΔSW, 5' ΔS is 1.5. Then, the final crown change on the exit side of the stand 5 is as follows.

Next, if we convert the exit crown change ΔC,j of the stand 5 to the exit crown change of the stand 5, we get ΔC, -η ・Δ
C5,j...(22)6, J5. Here, ΔC,j is the change in the crown of the stand 5 on the exit side ΔC,j converted into the change in the crown on the exit side of the stand 6.

Of the crown deviation ΔC6,j in equation (3), stand 5
With the crown control, the expression (22) becomes as follows.

Next, the exit crown deviation of the stand 6 (25) is controlled. This control can be performed in exactly the same way as in the case of stands 5 and 4.

teeth, ・・・・・・(26) The actuator value of stand 4 is determined so that.

The crown control of stand 4 is completely similar to the crown control of stand 5.

Control with. This control may be performed in exactly the same manner as in the case of stand 5, stand 4, and stand 3.

is controlled by (27). This control is performed in exactly the same way as in the case of stand 5, stand 4, stand 3, and stand 2.

Now, the exit side of stand 6 (RCL
). This roll coolant, that is, four rows are arranged so that the evaluation function J is minimized. Roll coolant control is performed by dividing the roll in the sheet width direction and controlling the diameter ΔR of the roll at each position in the sheet width direction by 1.3.

aR,.

1.J The protrusion 1 of the i stand with respect to the diameter R1 in the board width direction, J This is the side crown influence coefficient.

The above calculation is performed by the crown control means]9 in FIG. These calculation results are sent to adders 21 to 25 in each stand.
through the actuators 11 to 16 of each stand, and the plate crown is controlled through the control of each actuator.

As detailed above, the final stand of the continuous rolling mill is subject to flatness control, and each other stand is subject to crown control.
Furthermore, by controlling the crown according to equations (1) to (29) so that the exit side plate crown is minimized across the strip width direction, can.

The above embodiment is for the case of multiple stands, but if there is only one stand, it is possible to use that stand as a crown control stand and control the exit side plate crown in exactly the same manner within the allowable range of flatness. can.

Also, regarding the number of rolls in one stand, in the above embodiment, the case of 6 stages was explained, but the present invention is limited to that.2.3.4.If the actuator is increased or decreased in a 5-stage mill, etc., there is no problem. Similar crown control can be achieved.

〔Effect of the invention〕

By controlling the actuator of each stand so that the exit side plate crown is minimized across the width of the strip, and by performing feedback control of the plate crown, we can produce high-quality strips that simultaneously achieve the target values for flatness and plate crown. You can get it.

A block diagram showing an embodiment of the control device, FIG. 2 is an explanatory diagram showing the roll configuration of each stand in FIG. It is a graph.

1 to 6...Stand 7...Flatness J1.8...
Crown meter, 9...Setting calculation means, 10.1821~
26... Adder, 11-16 Actuator, 17
... flatness control means, 19 ... crown control means,
20...Strip.

Claims (1)

[Claims] 1. A strip is passed through a stand having an actuator that includes at least a rolling device, a bender, and a roll coolant device divided into a plurality of parts in the roll width direction so that the strip has a predetermined flatness and plate crown. In a shape control method in a rolling mill that controls an actuator to The plate crown is controlled by determining the setting values of each actuator except for the roll coolant device so as to minimize the sum of squares over the entire plate width, and the residual error of the plate crown is controlled by the roll coolant device. A shape control method in a rolling mill. 2. The strip is passed through a plurality of stands arranged in tandem, each having an actuator including at least a rolling device, a bender, and a roll coolant device divided into a plurality of parts in the roll width direction, so that the strip has a predetermined flatness and plate crown. In a shape control method in a rolling mill that controls actuators to The plate crown is controlled by determining the setting values of each actuator except for the roll coolant device so as to minimize the square sum of the difference between the deviation between the values and the crown effect of each actuator over the plate width. A shape control method in a rolling mill, characterized in that the residual difference of is controlled by the roll coolant device. 3. Passing the strip through a stand having an actuator including at least a rolling device, a bender, and a roll coolant device divided into a plurality of parts in the roll width direction, and controlling the actuator so that the strip has a predetermined flatness and plate crown. In a shape control device in a rolling mill, a crown meter installed on the exit side of the rolling mill measures the difference between the deviation between the set value of the plate crown, the actual value of the plate crown measured by the crown meter, and the crown effect of the actuator over the entire plate width. The plate crown is controlled by determining the output settings of each actuator except for the roll coolant device within the flatness tolerance range so as to minimize the sum of squares, and the residual error of the plate crown is controlled by the roll coolant device. 1. A shape control device for a rolling mill, comprising a control means for controlling the shape. 4. The strip is passed through a plurality of stands arranged in tandem each having an actuator as an actuator including at least a rolling device, a bender, and a roll coolant device divided into a plurality of parts in the roll width direction so that the strip has a predetermined flatness and plate crown. In a shape control device in a rolling mill that controls an actuator to The plate crown is controlled by determining the output setting value of each actuator except for the roll coolant device so as to minimize the square sum over the entire plate width of the difference between the deviation between the measured values and the crown effect of each actuator, a first control means for controlling the roll coolant device so as to eliminate a residual difference in the plate crown; a second control means for controlling an actuator of the final stand so that the flatness measured by the flatness meter becomes a predetermined value; A shape control device for a rolling mill, characterized by comprising: