JPH01258807A - Controlling method for plate width in tandem mill - Google Patents

Abstract

PURPOSE:To improve the controlling accuracy for a plate width by taking the variation of the plate width between stands, when tension to a stock to be rolled between the stands is varied, for the sum total of the variations of the respective plate thicknesses on the outlet part of the stand on an upperstream side and on the inlet part of the stand on a downstream side. CONSTITUTION:The measured values W5, W6 of plate widths by each width meter 1, 2 are read into a computing element 3 for tension variation. The computing element 3 for tension variation computes the tension variations DELTAt4, DELTAt5 in accordance with the measured values W5, W6 of the plate widths of each width meter 1, 2 and a plate width aimed value W5aim on the outlet side of a 5th stand F5 inputted from a setter 4, a plate width aimed value W6aim on the outlet side of a 6th stand F6 and influence coefficients alpha4, alpha55, alpha54 given by tension variation to the plate width. These are inputted respectively to a tension controller 5 and the tension controller 5 changes the respective tensions which is given to a strip by the respective tension applying devices A1, A2. As a result, the variation of the plate width caused on the outlet side of each stand which has made a disturbance conventionally in setting the tension variation is removed so that the controlling accuracy of the plate width can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a strip width control method using tension in a tandem rolling mill.

[Prior art]

Figure 4 shows the conventional sheet width control method using tension
2963, JP-A No. 61-52917), and is a schematic diagram showing the implementation state of F4. Fs and Ph are the 4th stand in a tandem mill consisting of 6 stands.

The fifth stand and the sixth stand are shown, respectively.

A tension applying device AI+^2 is provided between the fourth stand F4 and the fifth stand FS, and between the fifth stand F and the sixth stand F, and a tension applying device AI+^2 is provided between the fourth stand F4 and the fifth stand FS, and a tension applying device AI+^2 is provided between the fourth stand F4 and the fifth stand FS. A total width of 1.2 mm is provided between the space and the sixth stand F on the exit side.

The board width measurement value -1 obtained by the width gauge 1 is taken into the tension change amount calculator 13, and the board width measurement value W obtained by the width gauge 2 is taken into the tension change amount calculator 14, respectively.

The tension change amount calculation unit 13 receives the board width measurement value and the fifth stand F, which is input from the setting device 15, and the output side board width target value WSai.
Based on the influence coefficient α4 of the tension change between the 4th and 5th stands on the board width, the board width measurement value -, is the output side board width target value -
1, the amount of tension change Δt4 necessary to make the tension match 1 is calculated and outputted to the tension controller 16.

The tension controller 16 outputs a predetermined control signal based on the input tension change amount Δt4 to the tension applying device A1, and changes the tension applied to the strip S by the tension applying device A.

In addition, the tension change amount calculator 14 inputs the plate width measurement value −1 and the sixth stand F, which is input from the setting device 15, and the output side plate width target value −1.
6,! , and the influence coefficient α of the tension change between the 6th stands on the plate width, calculate the tension change amount Δ[, required to make the plate width measurement value −6 match the exit side plate width target value La1n. , and outputs this to the tension controller 17. The tension controllers 16 and 17 output a predetermined control signal based on the input tension change amount Δj4q Δt to the tensioning devices AI and ^2, and change the tension that each tensioning device A+ and Ax applies to the strip S. .

Tension change amount Δt4. The width reduction amounts Δ-2 and Δ-6 of the strip S due to Δt are expressed as the following equation (IL (2)).

Δ−5=α4 ・Δt4 ・・
・(1) Δ−b=α4 ・Δt4+α5 ・Δt,
(2) Therefore, the amount of sheet width correction necessary to make each sheet width measurement value -3, -6 match the sheet width target value WSmi@*W6mis, respectively, is calculated by ΔF6. Δ匈, these are each influence coefficient α4. α5 and tension change amount Δt4. Δts is expressed as in the following equation (3).

Therefore, the tension change amount Δt4. Δt is given by the following equation (4).

[Problem to be solved by the invention]

By the way, in the conventional method as described above, the amount of width contraction of the strip S due to tension change is determined by the tension applying device^1. ^2
The amount of width shrinkage that occurs between the tension applying devices A, A, and the stands F4. The width reduction amount between Fs and Fs is treated as negligible.

However, when the tension is actually changed using the tensioning devices A+ and Ax, width shrinkage occurs at both sides of the tensioning device AI+^2, that is, at the roll bite portions of the work rolls on the upstream and downstream individual stands. There is.

For example, the width shrinkage due to the tension change of the tension applying device At is the fifth
At the roll bite portion of stand F3 and the sixth stand, Δ33. Only Δll4S4 occurs. Conventionally, as a result of ignoring the width reduction amount Δh, the width reduction amount Δ
-2S was a disturbance in the tension change amount Δt4, and was an obstacle to improving the plate width control accuracy.

゛Figure 5 shows the results when the tension applied to the strip is varied by the tension applying device between the 5th stand F and the 6th stand F in the tandem rolling mill consisting of 6 stands shown in Figure 4. This is a graph showing the width reduction rate of the upstream stand exit side and the downstream stand passenger side, with the horizontal axis representing the inter-stand tension (kg/w'') and the vertical axis representing the width reduction rate (
Δ−/−) is shown. The φ mark plotted in the graph shows the width reduction rate for both the upstream stand exit side and the downstream stand passenger side, and the 0 mark plotted at the downstream stand exit side. .

The material of the target strip was C: 0.04%, M
n: 0.22%, Si: 0.01%,
Board width 945-1162 Tsuru, board thickness 2.30-2.50mm
belongs to.

As is clear from this graph, the amount of strip width reduction that occurs at the upstream stand exit side is certainly smaller than the amount of strip width reduction that occurs at the downstream stand entrance side, but the number of strip width changes between the stands It can be seen that ignoring it has a large effect on the plate width accuracy.

The present invention was made based on this knowledge, and its purpose is to provide a tension applying device.

To provide a strip width control method in a tandem mill, which eliminates disturbances by taking into account the amount of width shrinkage at each roll bit part in a downstream stand, and enables effective strip width control.

[Means to solve the problem]

In the strip width control method in a tandem mill according to the present invention, the influence coefficient is determined in advance for each of the upstream stand outlet side and downstream stand inlet side between the stands, and the tension on the rolled material between the stands is changed. The amount of change in board width at this time is taken as the sum of the amount of change in board width that occurs at the upstream stand exit side and the amount of board width change that occurs at the downstream stand exit side, taking into account each influence coefficient.

[Effect]

In the method of the present invention, the tension between the tensioning device and the upstream stand and between the tensioning device and the downstream stand and the influence coefficient on the board width are taken into consideration, and the tension is determined between the downstream stand and the upstream stand. This eliminates the problem that the width control output between the stand and the upstream stand disturbs the other width control outputs.

〔Example〕

The present invention will be specifically described below based on drawings showing its implementation state. FIG. 1 is a block diagram showing a control system for implementing the strip width control method in a tandem mill according to the present invention. - Fs and Fh are the 4th stand in a tandem mill consisting of 6 stands. 5th and 6th stands, A,
is the 4th and 5th stand F4. Tension applying device arranged between FS, A2 is tension applying device arranged between 5.6th stand FS + Fb stand, 1 is 5th and 6th stand FS, F
66 stand has a width gauge arranged, and 2 indicates a width gauge arranged on the exit side of the 6th stand Fb.

The board width measurement value using width gauge 1 is also the same as the board width measurement value using width gauge 2.
1 is read into the tension change amount calculator 3. The tension change amount calculator 3 calculates the board width measurements of each width gauge 1.2 -5, -5.
And the target value of the 5th stand FS exit plate width manually inputted from the setting device 4 -511! +6, 6th stand exit side board width target value W. ! , and the influence coefficient α4 of the tension change on the plate width.
α23. α3. Based on the tension change amount Δjl+Δt
, is manually input to each tension controller 5, and the tension controller 5 changes the tension applied to each strip S by each tension applying device AI+At.

FIG. 2 is a block diagram showing the calculation process of the tension change amount calculation unit 3, and the measured plate width values of the strip 1, -3 and 匈, detected by the width gauges 1 and 2 are input to the subtractors 31 and 32, respectively. is,
Board width target value input from setting device 4.4 - 5w1m
, W6+ai*, and output the differences Δ-1 and Δ-6 to a multiplier 33.34 and a subtracter 35.36, respectively.

The multiplier 33 calculates the plate width difference ΔW5 and the influence coefficient α55+α3 manually entered from the setting device 4. The multiplier 34 multiplies the value by the subtractor 35, and the multiplier 34 multiplies the plate width difference Δ-6 and the influence coefficient α1. input from the setting device 4. and outputs the value to the subtracter 35.

The subtractor 35 calculates the product Δ from the product Δ,・(α1.+α,6)
W,・α6. is subtracted, and the subtracted value is output to the divider 37.

Further, the subtracter 36 calculates the difference between the plate width differences Δ-1 and Δ-6, and outputs this to the divider 38.

The divider 37 converts the subtracted value input from the subtracter 35 into an influence coefficient (α, 4+α4%)・α, input from the setting value 4.
The resultant value is output to the tension controller 5 as the tension change amount Δt4.

Further, the divider 38 divides the subtracted value inputted from the subtracter 36 by the influence coefficient α56 inputted from the setting device 4, and outputs the value to the tension controller 5 as the tension change amount Δt. . The tension controllers 5 are tension applying devices A, . . .
The tension that At gives to the strip S is adjusted respectively.

To the tension applying device, the tension applied to the strip S by At4
When only the fourth stand F4. is changed, the fourth stand F4. The amount of width shrinkage that occurred in the roll bite part of the fifth stand F is Δ-44°Δ-4,
and when the tension applied to the strip by the tensioning device 2 is changed by Δt, in addition, the downstream No. 5.6
The amount of width shrinkage that occurred in the roll bite part of stand FS+ p& is set to Δ11. If Δ−, each tension change amount Δatt
, ts and width reduction amount Δ-44, Δw42. Δ6. .

The following relationship holds true between ΔWs&.

Δ-44=α44・Δt4...(
5a) Δen, ,=α4.・Δt4 ・
...(5b) Δga ss ”α55・Δt5
...(5C) Δ-%h ”α, h・Δt5
...(5d) However, α44: Influence coefficient α4. which the amount of change in tension between the tension applying device ^1 and the fourth stand F4 has on the amount of width contraction. : Influence coefficient α2 of the amount of tension change between the tension applying device A+ and the fourth stand F5 on the width shrinkage amount. : Tension applying device At and fifth stand F.

The influence coefficient α1 of the amount of change in tension on the amount of width reduction between : Influence coefficient of the amount of tension change between the tension applying device A2 and the fifth stand F6 on the amount of width reduction
Δ-44 shown in C). Δ-43. Δ−2, and in the following formula (6), the width reduction amount Δ−6 that can be captured by the width gauge 2 is calculated from Δga, #, Δga, 2. as shown in (5a) to (5c) above. Δ−
13. Δ-2, and are respectively expressed by the following equation (7).

Δ匈,=Δ−4. +Δ&44. 10Δ-1,...(6)
Δ-, = Δ-44+Δ-1S+Δ6. +Δ, 6...
(7) If the preset board width target value at the installation position of the width gauge 1 is -5w1m, and the board width measurement value of the width gauge 1 is 6, the board width correction amount Δh is expressed by the following equation (8).

ΔWs=Ws Wsais
...(8) Also, the preset board width target value at the installation position of the width gauge 2 is -makm, and the board width measurement value of the width gauge 2 is -.

Then, the board width correction amount Δ-1 is expressed by the following equation (9).

Δ-4=Mo-W6aia...(
9) Therefore, in order to make the board width correction amounts Δ-2 and Δ-6 respectively zero, Δ-5 in equations (6) and (7). In other words, the tension between the stands may be changed so that Δ-6 matches the plate width correction amounts Δ-1 and Δ-6, respectively, or in other words, the following equation 01.09 holds true.

Δ weak, = Δ−2 ・・・αl
Δ-6=Δ-6°°°aυ Substituting (6), (7), and (5a) to (5d) into each Δ-5 and Δ in the Ql and aD equations, we get Δbell 3. It can be rewritten as the following equation using the ΔGa and Hakekai equations.

Expression (2) is converted to Δt9. Solving for Δt gives the following equation α1.

...Q31 The above-mentioned sheet width control method applies to the 4.5 stands F- and Fs of a tandem mill consisting of 6 stands as shown in Fig. 1.
, 5th and 6th stands FS+
Although we have explained the case where the control is based on the plate width measurement value using each width gauge 1.2 placed on the stand F & exit side, the control is not limited to this in any way, and the tension provided between each stand of a tandem mill consisting of n stands Of course, the present invention can also be applied to the case where the application device is controlled based on the board width measurement value obtained by a width gauge provided on the outlet side of each stand. In this case, each tension change amount Δtl to Δt is given by the following formula Q4) and 051, which are generalized formulas (2) and a1, respectively.

(Margin below) ... α0 (If the first page on the right side of formula 141 is set as A, the (goods) formula becomes the following (+4) ' formula.

However, α mouth, α! ! '-'αa-1 a-1: Tension applying device A,, A.

The influence coefficient α of the amount of tension change between ... and its upstream stand P+, h... on the amount of width reduction, α! 3-'αh-+ a: Tension applying device A
,, At-... and its downstream stand F,,F! . . . The influence coefficient of the amount of tension change between the 1-
n) is given by the following α9 formula.

FIG. 3 is a graph showing the comparative test results when the method of the present invention and the conventional method are applied using a tandem mill consisting of six stands as shown in FIG. 1.4, respectively.
0.04%, Mn: 0.22%, St: 0.01
%, a strip with a thickness of 471 cm is finished with a thickness of 9 on the exit side.
It was heated to 00° C. and rolled to a target thickness of 2.3 fl and a target width of 1.33 m. In addition, the initial setting tension is 1.6 kg/v between the 4.5th stand F# and F3.
m”, tension between 5.6 stands is 1.4 kg/tx
h”, and the board thickness at the exit side of each stand was 3.7 m on the exit side of the 4th stand F4, 2.8 m on the exit side of the 5th stand, and 2.3 m on the exit side of the 6th stand. Figure 3 (B) shows the results when using the inventive method and when using the conventional method.The horizontal axis shows the position of each part of the strip from the top to the tail, and the vertical The axis shows the width deviation (crane) of each part in the longitudinal direction with respect to the average board width.

As is clear from this graph, when using the conventional method, there is a variation of 2.5n+ in board width, whereas when using the method of the present invention, the variation is 1.5 mm, which makes it easy to control the board width. It can be seen that the accuracy has been significantly improved.

〔effect〕

As described above, in the method of the present invention, the amount of strip width change between the stands that occurs when the tension on the rolled material between the stands is changed occurs at the exit side of the upstream stand and the entry side of the downstream stand. Since it is treated as the sum of plate width changes, the plate width change that occurs at the exit side of each stand, which conventionally was a disturbance when calculating the tension change amount, is removed, making it possible to significantly improve plate width control accuracy. The present invention has excellent effects.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the control system of the method of the present invention, Figure 2 is a block diagram showing the tension change amount calculation process, and Figures 3 (a) and (b) are comparisons between the method of the present invention and the conventional method. A graph showing the test results, FIG. 4 is a block diagram showing the control system of the conventional method, and FIG. 5 is a graph showing the influence coefficient of tension on the board width. 1.2... Width meter 3... Tension change amount calculator 4...
・Setting device 5...Tension controller F4+FS+F6
...4th, 5th. 6th stand AI+A2...
Tensioning device S...Strip patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono Mistakes Figure 1 (A) Figure 3

Claims (1)

[Claims] 1. The influence coefficient on the strip width when changing the tension on the material to be rolled between rolling stands is determined in advance, the width of the material to be rolled is measured, and the measured value of the strip width is determined in advance. The amount of plate width change required to match the plate width target value is determined, the amount of tension change is determined based on the plate width change amount and the influence coefficient, and the tension of the rolled material is changed to control the plate width. In a strip width control method in a tandem mill, the influence coefficient is determined in advance for each of the upstream stand outlet side and the downstream stand entry side between the stands, and the influence coefficient is The amount of width change is taken into consideration as the sum of the amount of board width change occurring at the upstream stand exit side and the board width change occurring at the downstream stand exit side, taking into account each of the above-mentioned influence coefficients. A strip width control method in a tandem mill characterized by: