JP2504403B2 - Strip width controller for tandem rolling mill - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method and apparatus for tension-based strip width control in a tandem rolling mill for rolling hot strips.

[Technical background of the invention and its problems]

Control of strip width in finish rolling of hot strip is
For example, several vertical rolling mills (edgers) are provided in the front stage of the finishing tandem mill, tension is generated between stands, and a width change due to the tension is used for plate width control. The method of installing the edger has the drawback that stable rolling is difficult, and in order to obtain the maximum good product with compact equipment, positively generate tension between stands,
It is more advantageous to obtain the board width. However, in plate width control based on tension, the relationship between tension and the amount of width change is not clearly understood.Therefore, the effect of width change by tension control is positively applied to the optimization of the pass schedule in the setting calculation. There remains a difficult problem to consider, and in the end, the effect of tension
It was not always possible to make full use of the control of the product plate width.

In this way, the cause that the plate width control by tension does not include the optimization of the pass schedule is whether the plate width change by tension occurs between the stands or in the roll bite, and
The effect on the width change in the roll bite is that the basic width change behavior of the plate, such as the front tension and the rear tension, was not fully understood. In other words, it is difficult to accurately fit the product target width into the product target width because the basic characteristics are not clear.

[Object of the Invention]

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a strip width control device for a tandem rolling mill capable of controlling the strip width with high accuracy.

[Outline of Invention]

The strip width control device for a tandem rolling mill according to the present invention is based on a deviation (ΔB) between the target width (B ^aim ) and the final (n) stand exit side width (▲ B ^D _n ▼) calculated, and the inter-stand tension ( t _i ) A tension calculator that calculates and sets the material thickness (H _TB ) or (i-1) stand outlet side thickness set value (H _i-1 ) and i stand outlet side thickness set value (H _i ) i stand inlet side width output by the calculation (▲ B ^E _i ▼) and on the basis of the output (t _i) of the tension calculator, i stand rolling during the forward tension width in bytes i stand by (t _i) Calculating and outputting the spread amount (ΔB _fi ), the above-mentioned tension lower bite inner width spread calculator, and i stand output side thickness set value (H _i ) and (i + 1) stand output side thickness set value (H _{i + 1} ) Based on the (i + 1) stand-in side width output (▲ B ^E _{i + 1} ▼) and the output (t _i ) of the tension calculator, i + 1) a backward tension lower bite internal width expansion calculator for calculating and outputting a width expansion amount (ΔB _{bi + 1} ) in the bite of the (i + 1) stand based on the backward tension (t _i ) during stand rolling, Material width (B _TB ) or i stand input side width output (▲ B ^E _i ▼) is added to i stand bit inside width expansion output (ΔB _fi ) under front tension, and i stand output side width (▲ B
^D _i ▼) an adder for outputting, based on the output of the i stand delivery side width (▲ B ^D _i ▼) and i stand delivery side thickness setting value (H _i) and the tension calculator (t _i) i and (i + 1) stand-to-stand narrowing calculator that calculates and outputs the width-to-stand narrowing amount (ΔB _si ) due to the tension between the stands, and the stand-to-stand narrowing amount from the i-stand output side width output (▲ B ^D _i ▼) A subtracter that subtracts the output (ΔB _si ) and outputs (i + 1) stand entrance side width (▲ B ^E _{i + 1} ▼) and the (i + 1) stand entrance side width (▲ B ^E _{i + 1} ▼) Under tension (i + 1) Stand bite inner width expansion amount output (ΔB
_{bi + 1} ) is added and (i + 1) stand output side width (▲ B ^D
_{i + 1} ▼), an adder, a subtractor that calculates and outputs the deviation (ΔB) between the target value (B ^aim ) and the n stand output side width (▲ B ^D _n ▼), and the width deviation (ΔB) ) Becomes 0, each stand main unit is adjusted so that the tension between each stand matches the tension reference based on the output of the above tension calculation unit of each stand tension reference (t _i , ... t _i , ... t _n-1 ). A tension control device for setting the rotation speed of the motor and a speed regulator for driving the main motor based on the rotation speed setting value of the main motor are provided.

Example of Invention

Hereinafter, for simplification, one embodiment of the present invention will be described taking the case of two stands as an example.

First, as shown in FIG. 1, the width B _TB and thickness H _{TB of} the material (the first stand (upstream stand) inlet side material) from the host computer 1 that manages the entire rolling system, and the first stand outlet side thickness H ₁ , and the target width B ^aim and target thickness H ^aim of the output side of the second stand (downstream side stand), that is, the product, are output. The plate thickness is H _TB → H ₁ (thickness at the 1st stand exit side) → H ^aim , and the roll opening of each stand is set according to the rolling schedule. Change. The width change is dominated by the amount of width expansion that occurs in the bite when rolled by a horizontal roll, but when front and rear tension is applied, the width expansion in the bite is suppressed by the tension, Narrowing occurs due to tension between stands. In this way, the width change behavior when tension is applied is the change that occurs in the bite of the horizontal roll,
It is possible to separate into the changes caused by the tension between stands, and by treating them separately, the factors affecting the width change can be distinguished (for example, the width change between stands causes the reduction rate of the horizontal roll to be It is irrelevant.) Only then can the tension be set so that the product plate width accuracy becomes good.

The control device according to the present invention is configured as shown in FIG. 1 in order to separate the width change within the cutting tool and the width change between the stands.

The material width setter 2 sets the material width based on the material width B _TB output of the _host computer. The material thickness setter 3 sets the material thickness based on the material thickness H _TB output of the _host computer. The delivery side thickness setter 4 sets the first stand delivery side plate thickness H ₁ based on the rolling-down schedule output of the host computer. The target width setting unit 5 sets the target width based on the target width B ^aim output of the ^host computer. The target thickness setter 6 is the target thickness of the host computer.
Set the target thickness based on the H ^aim output. Tension setting device 10
Is the width of the 2nd stand exit side calculated from the target width B ^aim ▲ B ^D ₂
The inter-stand tension t ₁ is calculated and set based on the deviation ΔB from ▼.

The front tension under bite width expansion calculator 7 determines the first stand based on the material thickness H _TB of the material thickness setter 3, the material width B _TB of the material width setter 2 and the output t ₁ of the tension calculator 10. The width expansion amount ΔB _f in the cutting tool of the first stand due to the front tension t ₁ during rolling is calculated and output. The rear tension lower bite width expansion amount calculator 8 calculates the first stand outlet side thickness set value H ₁ and the target thickness H ^aim of the outlet side thickness setter 4 and the second stand inlet side width output by calculation ▲ B ^E _{2 Based on} ▼ and the output t ₁ of the tension calculator,
The width expansion amount ΔB _b in the bite of the second stand due to the backward tension t ₁ during the rolling of the second stand is calculated and output. Adder 21
Adds the width expansion amount ΔB _f of the first stand bite under tension to the material width B _TB, and outputs the i stand output side width ▲ B ^D ₁ ▼.

The inter-stand width narrowing calculator 9 calculates the width of the first stand from the first stand and the second stand based on the first stand outlet side width ▲ B ^D ₁ ▼, the first stand outlet side thickness set value H ₁ and the output t ₁ of the tension calculator 10. Calculates and outputs the amount of narrowing ΔB _s due to tension. Subtractor 22
Subtracts the inter-stand width narrowing amount output ΔB _s from the 1st stand exit side width output ▲ B ^D ₁ ▼, and subtracts the 2nd stand entrance side width ▲ B ^E ₂
Output ▼. The adder 23 has a width on the second stand entrance side ▲ B ^E ₂
Output of width expansion of the 2nd stand bit under rear tension ΔB _b
Is added and the second stand output side width ▲ B ^D ₂ ▼ is output.
The subtractor 24 has a target width B ^aim and a second stand exit side width ▲ B ^D ₂ ▼
The deviation ΔB of is calculated and output.

The tension control device 11 of each stand main unit motor 13 adjusts the inter-stand tension to the tension reference based on the output from the tension calculator 10 of the first stand tension reference t ₁ when the width deviation Δ13 becomes 0. Set the rotation speed. Speed regulator
Reference numeral 12 drives the main engine motor 13 based on the rotation speed setting value of the main engine motor 13.

The arithmetic units 7, 8 and 9 described above are for separating the width change within the byte and the width change between the stands, and will be described in detail below.

The computing unit 7 uses the first stand to obtain the amount of width expansion ΔB _f in the bite when the front tension is applied. ΔB _f is B _TB , H _TB , H ₁ , t ₁ , R ₁ , M
It is a function of ₁ and k ₁ . That is, ΔB _f = ΔB _f (B _TB , H _TB , H ₁ , t ₁ , R ₁ , M ₁ , k ₁ ) (1) where R ₁ is the radius of the first stand work roll and M ₁ is Friction coefficient, k ₁ is deformation resistance.

The calculator 8 uses the second stand to determine the width expansion amount ΔB _b in the bite when the rear tension is applied.

ΔB _b = ΔB _b (▲ B ^E ₂ ▼, H ₁ , H _aim , t ₁ , R ₂ , M ₂ , k ₂ ) ... (2) The calculation is performed.

The computing unit 9 obtains the width narrowing amount ΔB _s caused by the tension between the first and second stands.

ΔB _s = ΔB _s (▲ B ^D ₁ ▼, H ₁ , t ₁ , k ₁ ) ... (3).

Expressed in this way, the width relationship at each position is as follows.

▲ B ^D ₁ ▼ = B _TB + ΔB _f (4) Here, ▲ B ^D ₁ ▼ is the width immediately after the first stand roll bite.

▲ B ^E ₂ ▼ = ▲ B ^D ₁ ▼ -ΔB _s (5) ▲ B ^E ₂ ▼ is the width immediately before the second stand roll bite.

▲ B ^D ₂ ▼ ＝ ▲ B ^E ₂ ▼ -ΔB _b …… (6) ▲ B ^D ₂ ▼ is the width immediately after the second stand roll bite.
Now, the case of two stands has been described, but the same applies to the case of multiple stands. Therefore, the deviation from the target width B ^aim is Δ
Letting B be, ΔB = B ^aim − ▲ B ^D ₂ ▼ (7). Here, in the case of ΔB = 0, when ΔT is set in the tension setter and, for example, the tension reference t ₁ is increased by Δt, ΔB changes and is obtained according to the same formula. Then, when ΔB = 0, the tension t ₁ is output as the tension reference of the constant tension control device, the main motor is further controlled, and the tension between the first and second stands is maintained at t ₁ , A product width that accurately matches the target width B ^aim can be obtained. FIG. 2 illustrates the width change behavior during this period.

As described above, the change behavior is separated in the bite and between the stands, and the reason that each can be controlled by that is demonstrated based on experimental facts. FIG. 3 and FIG. 4 show an example of the result of performing tandem rolling by applying tension with an experimental horizontal rolling mill, and FIG. 3 shows forward tension / deformation resistance (Δ
The effect of t _f / k) on the width change rate (ΔB _f / B _TB ), and Fig. 4 shows the width change rate (ΔB _b / ▲) of backward tension / deformation resistance (Δt _b / k).
B ^E ₂ ▼). In addition, each shows the result of measuring the change rate between stands and the change rate within the cutting tool separately. As can be seen from the figure, as the tension increases, the width expansion amount within the cutting tool decreases. This is forward,
The same phenomenon occurs with both rear tensions. On the other hand, the rate of change in width between the stands causes a narrowing of the width for the first time when the tension exceeds a certain tension, and the amount of narrowing increases as the tension increases. In this way, the width change behavior within the bite and the width change behavior between stands are distinctly different.Therefore, it is possible to separate these and configure an appropriate mathematical formula for each factor to control. I understand.

Next, as another embodiment, a case of an n-stand tandem mill will be described. Fig. 5 defines the plate width, plate thickness and tension at each position. That is, if the i-stand entry side width is ▲ B ^E _i ▼, the i-stand exit side width is ▲ B ^D _i ▼, the i-stand entry side thickness is H _i , and the tension between i and (i + 1) stands is t ₁ , B ^E _i ▼ = B _TB . Then, the width change amount in the cutting tool at the front tension t _{i at} the i stand is ΔB _if , (i
+1) width variation in the bytes in at the rear tension t _i stand ΔB _{(i + 1) f,} in the front tension i stand
The width change amount is represented by ΔB _{if, b} and i for t _i and backward tension t _(i-1).
If the amount of narrowing between the stands due to the tension t _i between the stands and the (i + 1) stand _{is set} to ΔB _is , the following relational expression holds. Note that # 1, ... #i, ... #n are respectively
1st, 2nd, ... ith, ... nth stand.

As shown in the above formula, in all stands (1,2, ..., n), the width expansion within the cutting tool and the width narrowing between stands are calculated sequentially, and the final final stand exit side width ▲ B ^D _n ▼ is required. Therefore, ▲ B ^D _n ▼ is compared with the target width B ^aim, and if deviation ΔB remains, t ₁ , t ₂ , ..., T _(n-1) is changed by the tension calculator 10, and ΔB = T _(n-1) , t _(n-2) , ..., t until 0
Change to ₁ and find all t ₁ with ΔB = 0. Δ
When B = 0 is achieved, t ₁ (i = 1, ..., (n−1))
Is set in the constant tension control device, and the plate width control is also completed when the constant tension control is performed so that the tension between the stands matches the set tension standard. Thus, the target plate width with the same accuracy as in the case of two stands can be achieved by the fact that the bite width expansion amount and inter-stand width reduction amount of all stands are separated and used individually for setting. Is.

In the above embodiment, the thickness reduction schedule of each stand is a case where it is already fixed, but for example, when the target width cannot be achieved only by changing the tension, the reduction is performed. It is also possible to change the schedule.

Further, in the embodiment of n stands, when ΔB = 0, a method of sequentially changing the tension between the stands at the rear stage to the tension at the front stage is described, but the present invention is not limited to this and, for example, Needless to say, the accuracy of the width control can be similarly improved by selecting several stands and implementing the present invention.

Further, instead of using a mathematical formula for the relationship between the tension and the like and the width change, the correspondence relationship between the tension and the like and the width change may be stored based on the experimental data and controlled by this.

〔The invention's effect〕

As is clear from the above description, according to the present invention,
The change behavior of the plate width depending on the tension is compared with the phenomenon that the width in the cutting tool is widened and the width between the stands is narrowed.
Since each is calculated and controlled separately, it is possible to efficiently control the plate width of the product with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the case of two stands of the present invention, and FIG. 2 is a diagram showing a width change behavior in that case,
FIG. 3 is a diagram showing the basis for separating the inside and outside of the roll bite of the width change behavior of the present invention when front tension is applied, FIG. 4 is a diagram when rear tension is similarly applied, and FIG. 6 is a diagram showing the definition of dimensions at each position in the case of the embodiment of FIG. 1 ... Host computer, 2 ... Material width setting device, 3 ... Material thickness setting device, 4 ... i stand output side thickness setting device, 5 ... Target width setting device, 6 ... Target thickness setting device, 7 …… Calculator for front widening tool width under tension, 8 …… Calculator for rear tension under cutting tool width, 9 …… Calculator for narrowing width between stands, 10 …… Tension calculator, 11 …… Tension controller, 12 …… Analog / digital speed regulator, 13 …… Main motor, 14 …… First stand roll, 15 …… Second stand roll, 16 ……
1st stand, 17 ... 2nd stand, 18 ... Width meter.

Claims (1)

(57) [Claims] 1. An inter-stand tension (t _i ) is calculated and set based on a deviation (ΔB) between a target width (B ^aim ) and a final (n) stand exit side width (▲ B ^D _n ▼) calculated. Tension calculator (1
0) and material thickness (H _TB ) or (i-1) stand outlet side thickness setting value (H
_i-1 ) and i stand output side thickness setting value (H _i ), i stand input side width output (▲ B ^E _i ▼) by calculation, and the output (t _i ) of the tension calculator (10), A front tension under-bite widening width calculator (7) for calculating and outputting the width expansion amount (ΔB _fi ) in the i-stand by the front tension (t _i ) during i-stand rolling, and the i-stand exit side Thickness setting value (H _i ) and (i + 1) stand output side thickness setting value (H _{i + 1} ), and (i + 1) stand input side width output (▲ B ^E _{i + 1} ▼) by calculation, and the tension calculator (1
Based on the output (t _i ) of (0), the width expansion amount (ΔB _{bi + 1} ) in the bite of the (i + 1) stand by the backward tension (t _i ) at the time of rolling the (i + 1) stand is calculated and output. Calculator (8) for widening the inside width of the tool under rear tension, and the width of the material (B _TB ) or the width of the input side of the i stand (▲ B
^E _i ▼) is added with an i-stand bite width expansion amount output (ΔB _fi ) under forward tension to output an i-stand output side width (▲ B ^D _i ▼); Stand stand-out side width (▲ B ^D _i ▼) and i stand stand-out side thickness set value (H _i ) and output (t _i ) of the tension calculator (10)
I and (i + 1) a stand narrowing calculator (9) that calculates and outputs a narrowing amount (ΔB _si ) due to the tension between the stands, and the i stand output side width output (▲ B ^D _i ▼) A subtracter (22) that subtracts the inter-stand width narrowing amount output (ΔB _si ) and outputs (i + 1) stand entrance side width (▲ B ^E _{i + 1} ▼); and (i + 1) stand entrance side width ( ▲ B ^E _{i + 1} ▼) to output the width expansion amount of the stand bite (i + 1) under rear tension (ΔB
_{bi + 1} ) is added and (i + 1) stand output side width (▲ B ^D
an adder (23) that outputs _{i + 1} ▼) and a subtractor (24) that calculates and outputs the deviation (ΔB) between the target value (B ^aim ) and the n stand output side width (▲ B ^D _n ▼) , The tension between the stands is determined based on the output from the tension calculator (10) of the stand tension standards (t _i , ... t _i , ... t _n-1 ) when the width deviation (ΔB) becomes 0. A tension control device (11) that sets the rotation speed of each stand main motor (13) so as to match the standard, and the speed at which the main motor (13) is driven based on the rotation speed setting value of the main motor (13). A strip width control device for a tandem rolling mill, comprising a regulator (12).