JPS5924886B2 - Plate width control method and device for hot rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a strip width control method and apparatus for a hot rolling mill,
In particular, the present invention relates to a method and apparatus for controlling the strip width of a hot rolling mill, which is suitable for use in a hot rough rolling mill, and which rolls a material to be rolled using vertical rolls and subsequent horizontal rolls.

Generally, a hot rolling mill, especially a hot rough rolling mill, is equipped with a vertical roll and a horizontal roll following the vertical roll, and the vertical roll adjusts the width of the sheet to a predetermined value, and the horizontal roll adjusts the sheet thickness to a predetermined value. .

However, even if the width of the sheet is controlled to a predetermined value by the vertical rolls, it is difficult to accurately obtain the desired width of the sheet at the exit side of the horizontal rolls due to the width expansion caused by the subsequent horizontal rolls.

In order to eliminate such drawbacks, for example,
In No. 4029, the rolled strip width is measured from the outputs of the rolling pressure detector and the vertical roll opening detector of both vertical rolls, and based on this strip width and the amount of strip width expansion due to the horizontal rolls, which is calculated and introduced in advance. The board width control is performed by a control device that predicts and calculates the horizontal roll exit side board width value and corrects the vertical roll opening degree based on the deviation from the board width setting value.

In addition, in JP-A No. 48-60062, the width of the plate before rolling required to reach the target plate width after rolling is calculated based on the relational expression for width expansion when horizontal reduction is applied, and The width of the plate is actually measured, and based on the deviation between the two, the necessary width correction amount is calculated before horizontal rolling, and the position of the vertical roll is adjusted.
The overall or local width expansion prediction error amount is calculated from a predetermined target sheet width value and an actual value measured by a sheet width meter on the exit side of the horizontal roll, and each coefficient is corrected.

However, in the former method, the mill rigidity of the vertical rolls is low, and the vertical rolls usually have a relatively large mechanical play, so the accuracy of detecting the sheet width as an absolute quantity is poor.

Furthermore, even if the width of the rolled strip at the exit side of the vertical rolls can be measured, the amount of dog bones generated by the vertical rolls is unknown, so there are drawbacks such as the difficulty in accurately predicting the amount of strip width undulation caused by the horizontal rolls. be.

On the other hand, in the latter method, the target strip width before vertical roll rolling is calculated based on the width expansion relational expression when horizontal reduction is applied, and the position of the vertical roll is adjusted based on the deviation from the signal from the entrance strip width gauge. However, calculating the target sheet width before vertical roll rolling is more difficult than the former method for the reasons mentioned above, and the purpose could not be fully achieved.

The present invention was made in order to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide a strip width control method and apparatus for a hot rolling mill that can accurately obtain a target strip width.

The present invention provides a strip width control method for a hot rolling mill that rolls a material to be rolled using a vertical roll and a horizontal roll following the vertical roll.
Detecting the width of the rolled material plate on the entry side and exit side of the vertical roll,
Using these sheet widths and the horizontal roll entry-side and exit-side sheet width relational expressions that include at least the vertical roll entrance side sheet thickness and the horizontal roll exit side sheet thickness, the target horizontal roll exit side sheet width can be obtained. The above object is achieved by adjusting the opening degree of the vertical rolls.

Further, in the same strip width control device of a hot rolling mill, a strip width target value setting means for setting a target strip width on the exit side of the horizontal rolls, and a strip width for measuring or A plate width detection means for calculating the plate width, an entrance plate thickness detection unit for detecting the vertical roll entry side plate thickness of the rolled material, an exit side plate thickness detection unit for detecting the horizontal roll exit side plate thickness of the rolled material, and A rolling length detection means for detecting the rolling length, and the output of each of the detection means includes the width of the vertical roll inlet and outlet sides, at least the thickness of the vertical roll inlet side, the thickness of the horizontal roll outlet side, and the rolling length. , using the horizontal roll entry and exit side sheet width relational expressions, obtain a predicted value of the horizontal roll exit side sheet width or the target horizontal roll exit side sheet width set by the sheet width target value setting means. a sheet width calculating means for calculating a vertical roll exit side sheet width target value, a horizontal roll exit side sheet width predicted value outputted from the sheet width calculating means and a target horizontal roll exit side sheet width outputted from the sheet width target value setting means; The opening degree of the vertical rolls is adjusted so as to eliminate the deviation between the vertical roll exit side board width target value output from the board width calculation means and the actual vertical roll exit side board width output from the board width detection means. By providing a vertical roll opening adjustment means for adjusting the opening degree, the above object is also achieved.

The present invention will be explained in detail below.

It is difficult to analytically obtain numerical solutions for the behavior of changes in sheet width when a material to be rolled is rolled using vertical rolls and subsequent horizontal rolls, so it is determined experimentally.

That is, qualitatively, when the material to be rolled passes through the vertical rolls,
Rectangular cross section as shown in Figure 1A (plate width w1 plate thickness H)
The rolled material 10 has a so-called dogbone cross-sectional shape (plate width WE1 central part thickness H) in which the effect of vertical rolls does not extend to the center gusset of the rolled material 10, as shown in FIG. 1B.
becomes.

When this rolled material 10 further passes through the horizontal rolls, the first
As shown in Figure C, the raised portions at both ends disappear, but at this time, the plate width increases, which is called width return (plate width WH1 plate thickness h).

This increase amount (WHWE) is the simple width expansion amount due to the horizontal roll assuming that there are no raised parts at both ends,
It is thought that it is obtained as the sum of the amount of width expansion due to the raised portions at both ends.

Therefore, the distance between the thickness WE of the vertical roll exit side of the rolled material 10 in the state shown in FIG. 1B and the width wH of the horizontal roll exit side of the rolled material 10 in the state shown in FIG. The relationship shown is experimentally established.

WH-WE10WH1+WH2・・・・・・・・・ (1
) Here, WHL is a simple width expansion amount due to the horizontal roll assuming that there are no raised portions at both ends, and is expressed by the following equation using Beese's equation, for example.

Here, H is the thickness of the horizontal roll, that is, the entrance side of the vertical roll, h
is the plate thickness at the exit side of the horizontal roll, and cH is the plate thickness H1 and the plate width WE1
This is a constant determined by the roll contact arc length.

Also, the width expansion amount WH due to the raised portions at both ends of the rolled material
2 is expressed, for example, by the following equation.

WH,F'f(Ht h + W + X)
W WB ) ... (3) Here, W is the width of the vertical roll entry side plate of the material to be rolled 10, f (H+ h t W,
) is a function of the entrance plate thickness H1, the exit plate thickness 1, the plate width W, and the length X of the rolled material from the tip, and is determined experimentally.

An example of experimental results showing the relationship between the vertical roll exit side plate width WE and the horizontal roll exit side plate width WIJ is shown in FIG.

In the figure, ○ marks are H: 65 dragon, h-40 mrtt,
Experimental results in the case of W = 1100 mm, * mark is the experimental result at the tip of the rolled material in the same case as above, △ mark is,
H = 260mm, h =: 210mm, W 1
It shows the experimental results in the case of 900 mm.

As is clear from the above experimental results, by detecting the inlet side plate width W and the outlet side plate width wE of the vertical roll, it is possible to accurately predict the horizontal roll outlet side plate width WH, and therefore,
Highly accurate control becomes possible.

Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 3, this embodiment uses a hot rough rolling mill in which a material to be rolled 10 is rolled by a vertical roll 12 and a horizontal roll 14 following this, with a target horizontal roll outlet plate width W.
A plate width target value setting device 30 for setting H, an input side plate width measuring device 32 installed on the input side of the vertical roll 12 and measuring the input side plate width W of the vertical roll 12, and an input side plate width measuring device 32 installed on the input side of the vertical roll 12. A speed detector 3 installed to detect the speed V of the rolled material 10
4, a signal transfer device 36 that transfers the output W of the input side plate width measuring device 32 to just below the vertical roll 12 according to the output V of the speed detector 34; Distance meters 38a and 3 that measure the distance to the roll 12
8b and the output of the distance meters 38a + 38b, the vertical roll exit side plate width W is determined from the preset installation interval between the distance meters 38a and 38b and the roll diameter of the vertical roll 12.
A vertical roll outlet side plate width calculation unit 40 that calculates E, and a downstream position detector 42 that is disposed on the upstream horizontal roll 16 and detects the input side plate thickness H of the rolled material 10 from the rolling position of the horizontal roll 16. , a rolling position detector 44 that detects the thickness of the horizontal roll outlet side of the rolled material 10 from the downstream position of the horizontal roll 14 of the rolling mill, and a rolling position detector 44 that detects that the rolled material 10 is caught in the vertical roll 12. a biting detector 46, a rolling length calculator 48 for calculating the rolling length X from the tip of the material to be rolled 10 from the output of the biting detector 46 and the output of the speed detector 34, and the signal transfer Based on the outputs of the device 36, the calculator 40.4B, and the detectors 42 and 44, the vertical roll entrance side plate width W1 of the rolled material 10, the exit side plate width WE1, the vertical roll entrance side plate thickness H1, the horizontal roll exit side plate thickness and rolling length X Horizontal roll exit side sheet width calculation for calculating the predicted value wH of the horizontal roll exit side sheet width using the sheet width relational expressions on the entrance side and exit side of the horizontal roll shown in equations (1) to (31) above. 50, the output WH of the horizontal roll outlet sheet width calculator 50, and the sheet width target value setting device 3.
The vertical roll opening degree control device 52 outputs a control signal to the motor 18 for adjusting the opening degree of the vertical roll 12 based on the deviation of the output WH of 0.

The action will be explained below.

The rolled material 10 that has entered the horizontal roll 16 of the upstream rolling mill
is a rolling position detector 42 disposed on the horizontal roll 16.
Accordingly, the plate thickness is detected from the rolled down position of the horizontal roll 16, and is inputted to the horizontal roll outlet side plate width calculator 50 as the vertical roll entry side plate thickness H.

The material to be rolled 10 that has left the horizontal roll 16 is measured at the entry side of the vertical roll 12 by an entry side board width measuring device 32 for its hard roll entry side board width W.

The input plate width W output from the input plate width measuring device 32 is determined by the signal transfer device 36 in response to the output signal of the speed detector 34 that detects the rolling speed V of the material to be rolled 10. 12, it is input to the horizontal roll exit side sheet width calculator 50 as the vertical roll entrance side sheet width W.

Further, the vertical roll exit side plate width WE of the rolled material 10 is calculated by the vertical roll exit side plate width calculator 40 according to the output signal of the distance meter 38 a t 38 b that measures the position of the vertical roll 12, and It is input to the horizontal roll exit side board width calculator 50.

At this time, depending on the output signal of the biting detector 46 disposed on the vertical roll 12 and the output signal of the speed detector 34, the rolling length X from the rolling tip of the material to be rolled 10 also changes from the horizontal roll It is input to the side plate width calculator 50.

Further, when the material to be rolled 10 reaches the horizontal roll 14 of the rolling mill, the downstream position detector 44 disposed on the horizontal roll 14 detects the thickness of the material to be rolled 10 on the exit side of the horizontal roll, and It is input to the horizontal roll outlet side plate width calculator 50.

In the horizontal roll outlet side plate width calculator 50, the above-mentioned (1) to (
3) Based on the formula, a predicted value wH of the width of the horizontal roll exit side plate under the rolling conditions is calculated.

The predicted value wH calculated by the horizontal roll exit side board width calculation unit 50 is compared with the horizontal roll exit side board width target value wH output from the board width target value setting device 30 set in advance, and according to the deviation, The vertical roll opening degree control device 52 controls the motor 18 to adjust the opening degree of the vertical roll 12 so that the deviation between the two is eliminated.

In the above embodiment, the target horizontal roll outlet width wH is set by the plate width target value setting device 30, and apart from this, the horizontal roll output width is set based on the relationship between the vertical roll outlet width WE and the horizontal roll outlet width. The outlet side plate width WH was predicted and the opening degree of the vertical roll was adjusted based on the deviation. It is also possible to determine the opening degree of the vertical roll from the relational expression between the exit side board width and the horizontal roll exit side board width, and from the deviation between the vertical roll exit side board width target value and the actual vertical roll exit side board width.

In addition, in the above embodiment, the target value of the horizontal roll outlet plate width was set to a constant value, but the length from the tip of the rolled material
It is also possible to change it depending on the situation.

Furthermore, a board width gauge is installed downstream of the horizontal roll 14,
It is also possible to modify the calculation formula for the horizontal roll exit side sheet width using signals of the target horizontal roll exit side sheet width and the actual sheet width.

Further, in the above embodiment, the horizontal roll outlet side plate width calculation equations are equations (1) to (3), but the form of the equations may be changed as long as the signals used are the same.

Furthermore, in the embodiment described above, the width of the exit side plate of the vertical roll is determined from the actual opening degree of both vertical rolls, but it is also possible to determine it by other methods.

In addition, in the above embodiment, the vertical roll entrance side plate thickness H and the horizontal roll exit side plate thickness were both detected from the roll opening degree of the horizontal opening 6, but it is also possible to install a plate thickness meter. It is.

As explained above, according to the present invention, a target strip width can be obtained with high precision in a hot rolling mill.

Therefore, it has excellent effects such as reducing the margin of board width for finished products and reducing downgrades due to insufficient board width.

[Brief explanation of the drawing]

Figures 1A-C are cross-sectional views showing changes in the cross-sectional shape of a rolled material in a hot rolling mill, and Figure 2 is a relationship between the width of the inlet side of the horizontal roll and the width of the outlet side of the horizontal roll, showing the principle of the present invention. FIG. 3 is a block diagram showing the configuration of an embodiment of the strip width control device for a hot rolling mill according to the present invention. 10... Material to be rolled, 12... Vertical roll, 14... Horizontal roll, 30... Strip width target value setter, 32... ... Entrance board width measuring device, 34
...Speed detector, 36...Signal transfer device, 38 a + 38 b...Distance meter, 40...
・・・Vertical roll outlet side board width calculator, 42, 44...
・・Down position detector, 46・・・・Bite detector,
48... Rolling length calculator, 50... Horizontal roll exit side plate width calculator, 52... Vertical roll opening control device.

Claims (1)

[Scope of Claims] 1. In a hot rolling mill that rolls a material to be rolled using a vertical roll and a horizontal roll following the vertical roll, the width of the material to be rolled is detected on the entrance and exit sides of the vertical roll, and Predict the width of the horizontal roll exit plate using a relational expression for the width of the horizontal roll entry and exit sides that includes at least the vertical roll entry side thickness and the horizontal roll exit side thickness, and use this predicted value as the target. A strip width control method for a hot rolling mill, characterized in that the opening degree of the vertical rolls is adjusted based on the deviation from the strip width on the exit side of the horizontal rolls. 2. In a strip width control device for a hot rolling mill that rolls a material to be rolled using a vertical roll and a horizontal roll following the vertical roll, a strip width target value setting means for setting a target strip width at the exit side of the horizontal roll; A plate width detection means for measuring or calculating the width of the rolled material on the entry side and the exit side; an entry side plate thickness detection means for detecting the vertical roll entry side thickness of the rolled material; and a plate thickness of the rolled material on the horizontal roll exit side. An exit side plate thickness detection means detects the rolling length of the rolled material, a rolling length detection means detects the rolling length of the rolled material, and the outputs of the respective detection means are used to determine the input side and exit side plate widths of the vertical rolls and at least the input side plate width of the vertical rolls. A predicted value of the horizontal roll outlet side plate width or the plate width target value setting means using a plate width relational expression on the inlet side and the outlet side of the horizontal roll, including the side plate thickness, the horizontal roll outlet side plate thickness, and the rolled length. board width calculation means for calculating a target value of vertical roll exit side board width to obtain the target horizontal roll exit side board width set in , and a horizontal roll exit side board width predicted value outputted from the board width calculation means and the board width. The deviation between the target value of the horizontal roll outlet side plate width outputted from the target value setting means, or the deviation between the vertical roll outlet side plate width target value outputted from the plate width calculating means and the actual vertical roll outlet side plate width outputted from the plate width detection means. means for calculating the deviation of
A strip width control device for a hot rolling mill, comprising: a vertical roll opening degree adjusting means for adjusting the opening degree of the vertical rolls so as to eliminate this deviation.