EP2906369B1 - Width-altering system for strip-shaped rolled material - Google Patents

Description

Field of engineering

The present invention relates to a method for influencing the width of a strip-shaped rolling stock, in particular before hot rolling, during hot rolling or after hot rolling of the rolled stock in a hot rolling mill.

During hot rolling, a metallic rolling stock, for example a strip-shaped rolling stock made of steel or aluminum, is plastically deformed warm in a rolling nip of a roll stand.

• Produktion des Walzguts mit einer ersten Breite B₁, wobei das Walzgut aus dem ersten Aggregat mit einer Breite B = B₁ austritt und das austretende Walzgut zum zweiten Aggregat transportiert wird;
• Produktion eines Übergansstücks des Walzguts, wobei das Walzgut aus dem ersten Aggregat mit der Breite B mit B₁ ≤ B ≤ B₂ austritt;
• Produktion des Walzguts mit einer zweiten Breite B₂, wobei das Walzgut aus dem ersten Aggregat mit der Breite B = B₂ austritt.

The invention relates to a method for influencing the width of a strip-shaped rolling stock, wherein the rolling stock passes uncut through a first aggregate and a second aggregate and the rolled stock is rolled in a rolling mill in the first aggregate and / or in the second aggregate, comprising the following method steps:

• Production of the rolling stock with a first width B ₁ , wherein the rolling stock from the first unit with a width B = B ₁ exits and the emerging rolling stock is transported to the second unit;
• Production of a transition piece of the rolling stock, wherein the rolling stock from the first aggregate with the width B with B ₁ ≤ B ≤ B ₂ emerges;
• Production of the rolling stock with a second width B ₂ , wherein the rolling stock from the first aggregate with the width B = B ₂ emerges.

State of the art

From the prior art it is known to change the width of a continuously produced slab strand in a continuous casting machine by moving at least one narrow side wall in the mold. Furthermore, it is known to couple a continuous casting machine inline with a hot rolling mill, so that the hot rolling mill can immediately hot roll a uncut or cut slab strand produced in the continuous casting machine. Such a coupling of a casting machine to a hot rolling mill is called a cast -roll compound plant (also known as Thin Slab Casting and Rolling Plant, or TSCR for short); the uncut directly coupled operation of the casting and rolling plant is called continuous operation (engl. endless operation). An example of a cast-rolling compound plant that can be operated very endlessly is the Arvedi ESP (Endless Strip Production) plant.

Furthermore, it is known to produce a rolling stock with a different width with a cast-rolling composite plant. Typically, the width of the slab strand is changed in the mold, whereby a tapered or wider slab piece (also called transition piece or wedge-shaped transition piece) with a certain length (depending on the casting speed and the travel speed of the narrow side wall) is produced. The slab with the transition piece is then rolled in the rolling mill of the composite plant, which in any case a slowly tapered or slowly wider rolled strip is produced.

Since the slowly changing width band can not generally meet the width tolerances, it is disadvantageous that the band can not be sold directly with the rolled transition piece. Consequently It is desired to keep the length of the transition piece as short as possible. This can be done either by cutting out the transition piece from the slab or from the rolled strip, which in any case considerable Verlbringverluste arise. Furthermore, the transition piece can be trimmed or trimmed, whereby the Ausbringverluste can be reduced slightly. A very fast adjustment of the narrow side walls in the mold is also eliminated, since this can easily lead to breakthroughs in the thin strand shell of the slab strand.

How the Ausbringverluste further reduced and the reliability can be maintained at a high level, is not apparent from the prior art.

• Produktion des Walzguts mit einer ersten Breite B₁, wobei das Walzgut aus dem ersten Aggregat mit einer Breite B = B₁ austritt und das austretende Walzgut zum zweiten Aggregat transportiert wird;
• Produktion eines Übergansstücks des Walzguts, wobei das Walzgut aus dem ersten Aggregat mit der Breite B mit B₁ ≤ B ≤ B₂ austritt; und
• Produktion des Walzguts mit einer zweiten Breite B₂, wobei das Walzgut aus dem ersten Aggregat mit der Breite B = B₂ austritt.

From the US 4651550 A a method for influencing the width of a strip-shaped rolling stock is known, wherein the rolling stock passes through a first unit and a second unit uncut and the rolling stock is rolled in a rolling stand in the first unit and / or in the second unit, comprising the following method steps:

• Production of the rolling stock with a first width B ₁ , wherein the rolling stock from the first unit with a width B = B ₁ exits and the emerging rolling stock is transported to the second unit;
• Production of a transition piece of the rolling stock, wherein the rolling stock from the first aggregate with the width B with B ₁ ≤ B ≤ B ₂ emerges; and
• Production of the rolling stock with a second width B ₂ , wherein the rolling stock from the first aggregate with the width B = B ₂ emerges.

Summary of the invention

The object of the invention is to overcome the disadvantages of the prior art and to provide a method for influencing the width of a strip-shaped rolling stock, with which the length of a rolled transition piece, which is outside the width tolerances, can be reduced. This should reduce the Ausbringverluste.

• Produktion des Walzguts mit einer ersten Breite B₁, wobei das Walzgut aus dem ersten Aggregat mit einer Breite B = B₁ austritt und das austretende Walzgut zum zweiten Aggregat transportiert wird;
• Produktion eines Übergansstücks des Walzguts, wobei das Walzgut aus dem ersten Aggregat mit der Breite B mit B₁ ≤ B ≤ B₂ austritt;
• Produktion des Walzguts mit einer zweiten Breite B₂, wobei das Walzgut aus dem ersten Aggregat mit der Breite B = B₂ austritt;

erfolgt die Lösung dadurch, dass die Balligkeit zumindest einer Arbeits- und/oder zumindest einer Stützwalze des Walzgerüsts in Abhängigkeit eines Breitenfehlers e = B_Soll - B zwischen einer Soll-Breite B_Soll und der Breite B des Walzguts eingestellt wird, wobei bei e > 0 die Balligkeit erhöht und bei e < 0 die Balligkeit reduziert wird.The object of the invention is achieved by a method for influencing the width of a strip-shaped rolling stock, wherein the rolling stock passes uncut through a first unit and a second unit and the rolling stock is rolled in a rolling stand in the first unit and / or in the second unit, comprising the following method steps:

• Production of the rolling stock with a first width B ₁ , wherein the rolling stock from the first unit with a width B = B ₁ exits and the emerging rolling stock is transported to the second unit;
• Production of a transition piece of the rolling stock, wherein the rolling stock from the first aggregate with the width B with B ₁ ≤ B ≤ B ₂ emerges;
• Production of the rolling stock with a second width B ₂ , wherein the rolling stock from the first aggregate with the width B = B ₂ emerges;

the solution is achieved by setting the crowning of at least one working roll and / or at least one support roll of the roll stand as a function of a width error e = B _setpoint B between a desired width B _setpoint and the width B of the rolling stock, with e> 0 the crown is increased and at e <0 the crown is reduced.

In a rolling stand as the first and / or second unit, the crowning of a working or support roller of the rolling stand can be adjusted depending on the width error e additionally or alternatively to influence the train of the rolling stock, wherein at e> 0 increases the crown of the roller and e <0 the crown of the roller is reduced. Under crown, the central crown (engl. Central crown) is to be understood here as the thickness of the rolled material is reduced in a central area with an increase of the crown, so that the widening of the rolled material is increased during rolling. On the other hand, in the case of a negative latitude error e, the central crown is reduced, so that the spread during rolling is reduced. The adjustment of the crown of a roll can be done eg via roll bending actuators or via a thermal influence (eg a zone-dependent cooling) of the roll. If, in the case of thermal influence, an increase in crowning is desired, the cooling of the edge regions of the roll is increased more than the central regions. As a result, the central area of the roller expands more than the edge areas, whereby the crown is increased. On the other side is the crown reduced when the cooling in the central region of the roller is increased more than in the edge regions.

In order not to change the geometry of the rolling stock by setting the crown for width control, it is advantageous if both units have a roll stand, and a change in the crown of a roll takes place mainly in the first unit. This ensures that the rolled product after rolling in the second unit has a desired geometry.

Also, the adjustment of the crown as a function of the width of the error e can be carried out either controlled or regulated, ie taking into account the measured width _B of the rolled material, for example, at the exit from the second unit or later at an additional location.

In particular, when setting the crown, it is very advantageous to take into account the transport time of the rolling stock from the first unit or from a measuring device for detecting the actual width B _actual to the rolling stand. As a result, the width in the transition piece in the rolling stand of the second unit is compensated in the correct time. The consideration of the transport time can also be used when setting the train for width control.

Since normally only bands with a certain width can be sold, it is advantageous if the desired width B _{Soll is} a jump function H (t) from B ₁ to B ₂ or from B ₂ to B ₁ . Alternatively, the desired width B _{Soll may} also be a ramp function R (t) from B ₁ to B ₂ or from B ₂ to B ₁ . Of course, other functions are possible.

In general, it is useful if the first aggregate is a mold of a casting machine, e.g. a continuous arc casting machine or a two-roll casting machine, or a rolling stand, e.g. a rolling stand of a roughing mill.

In particular, during hot rolling in a hot rolling mill, it is expedient to transport the rolling stock from the first unit on a roller table to the second unit. The invention is by no means limited thereto, but operates e.g. also for freely suspended loops between two aggregates.

Brief description of the drawings

• Fig 1 und Fig 8: je eine schematische Darstellung eines Teils einer Gieß-Walz-Verbundanlage zur Durchführung der Breitenbeeinflussung eines bandförmigen Walzguts zwischen einer Stranggießmaschine und einem Vorwalzwerk
• Fig 2 und Fig 5: je eine Darstellung der Breite B_KOkille des Walzguts bei der Kokille, der Breite B_Treibrolle bei der Treibrolle und der Soll-Breite B_Soll an der Position der Treibrolle über der Zeit zur Ausführungsform nach Fig 1
• Fig 3 und Fig 6: je eine Darstellung des Breitenfehlers e über der Zeit an der Position der Treibrolle zur Ausführungsform nach Fig 1
• Fig 4a: ein Steuerungsschema zur Durchführung des erfindungsgemäßen Verfahrens
• Fig 4b, Fig 7 und Fig 10: je ein Regelungsschema zur Durchführung des erfindungsgemäßen Verfahrens
• Fig 9: eine Darstellung unterschiedlicher Breiten über der Zeit zur Ausführungsform nach Fig 8

Further advantages and features of the present invention will become apparent from the following description of non-limiting embodiments, reference being made to the following figures, which show the following:

• Fig. 1 and Fig. 8 Each of a schematic representation of a part of a casting-rolling composite plant for carrying out the width control of a strip-shaped rolling stock between a continuous casting machine and a roughing mill
• Fig. 2 and Fig. 5 a representation of the width B _{KOkille of} the rolling stock at the mold, the width B _{drive roller} at the drive roller and the target width B _Soll at the position of the drive roller over time to the embodiment according to Fig. 1
• Fig. 3 and Fig. 6 Each of a representation of the width error e over time at the position of the drive roller to the embodiment according to Fig. 1
• Fig. 4a a control scheme for carrying out the method according to the invention
• 4b . Fig. 7 and FIG. 10 Each a control scheme for carrying out the method according to the invention
• FIG. 9 : A representation of different widths over time to the embodiment according to Fig. 8

Description of the embodiments

The Fig. 1 shows a part of a cast-rolling composite plant with a sheet continuous casting machine 1 for the continuous casting of molten steel into thin slabs and a subsequent, in-line, rolling mill. From the rolling mill, only a rolling stand 7 of the roughing mill was shown; on the presentation of the other parts of the system has been omitted. In the mold 8, liquid steel is continuously cast into a thin slab strand, initially the width of the strand B = B ₁ = 1800 mm and its thickness is 90 mm. The casting speed 11 is 5 m / min; the metallurgical length of the continuous casting machine 1 from the mold 8 to the two driving rollers 10 is 15 m. Subsequent to the mold 8 of the thin slab strand is supported in the strand guide 9, guided and further cooled, the strand durcherstarrt in the last third of the arcuate strand guide 9. The strand guide 9 is indicated by two strand guide rollers. The solidified thin slab strand exits via the drive rollers 10 from the continuous casting machine 1 and represents the rolling stock 5. The pair of drive rollers 10 forms the first unit 2. The rolling stock 5 is in the transport direction 6 from the first unit 2 uncut on the roller table 3 to the second unit 4 out, wherein the second unit 4 by a rolling stand. 7 the roughing line is formed. Rolled product 5 rolled in the rolling stand is also referred to as rolled product 12.

If now another width of the rolled product 12 is desired, the two narrow side plates of the mold 8 are moved transversely to the casting direction. For example, during the continuous operation of the cast-rolled composite plant, the two narrow side plates are moved from B ₁ = 1800 mm to B ₂ = 1850 mm at a travel speed of 50 mm / min. By this movement is formed after the mold 8 in a width-changing, wedge-shaped thin slab strand (also called transition piece) in the strand guide 9 from. The width B _{mold of} the thin slab strand at the exit from the mold 8 or at the exit of the rolling stock 5 from the first unit 2 B _{drive roller} are in Fig. 2 shown in solid lines. Due to the length of the continuous casting machine, the head of the transition piece emerges from the first unit 2 with a delay of 3 minutes from the mold 8.

For width adjustment in the mold it is noted that in the production of thin slabs usually the narrow sides of the mold slowly inclined at the beginning of the transition piece, then move the inclined plates, and finally the inclined plates are returned to their original inclination. This has the advantage that the strand is better supported by the mold walls. The widths B _chill and B _{drive pulley} in this process are in Fig. 2 shown in phantom.

Furthermore is in Fig. 2 the desired width B _{target of} the rolling stock 5 is shown, wherein the target width mathematically as B _target = 1800 + 50th H (240) can be written, with the Heaviside hop function H (t) going from zero to one at 240 s jumps. For example, the jump function is known from http://mathworld.wolfram.com/HeavisideStepFunction.html.

The principle of the invention is based on the fact that, depending on the width error e with e = B _setpoint B, the tension on the rolling stock 5 between the first unit 2 (specifically the pair of driving rollers 10) and the second unit 4 (the rolling stand 7 of FIG Vorwalzstraße) is changed, with a negative e of the train σ is increased to the rolling stock 5 in the transport direction 6. Thus, the rolling stock 5 is constricted by the train, whereby the width of the rolling stock 5 and the rolled product 12 is reduced.

The width error e is in Fig. 3 shown. On the representation of the width error e for the in Fig. 2 dash-dotted widths was waived.

A control scheme for implementing the method according to the invention is in Fig. 4a shown. Specifically, the width error e is determined by the difference between the target value for the width B _desired and the width B, wherein B is determined by the width of the thin slab strand at the exit of the mold 8, taking into account a dead time of 3 min by the dead time member 13. The width error is then amplified by an amplifier member 14 and held by the limiting member 15 within allowable minimum and maximum limits. The result σ _Soll is fed to a tension regulator R _σ for the rolling stand 7, which adjusts the tension σ to the rolling stock 5 accordingly. The manipulated variable u is switched to the controlled system G, wherein the controlled system G as output an actual width B _{actual of} the rolled product 12 at the exit from the second unit 4 supplies.

The main difference between the control scheme in Fig. 4a and the control scheme in 4b is that the actual width B _{actual of} the rolled product 12 is measured immediately after exiting the second unit 4 by the width measuring device 16 (see Fig. 1 ) and the control loop is returned, so that the accuracy of the width control can be significantly increased.

Of course, it would also be possible to choose another function for the target width B _target , for example as in Fig. 5 , However, such a choice leads to positive and negative values for the width error e for the same width values B, so that the control according to FIG Fig. 4a or the regulation according to 4b with positive values of e, the rolling stock 5 is upsetting. The compression of the width of the rolling stock 5 is increased.

In any case, the actual width B _{actual of} the rolled product 12 is held closer to the desired width B _desired by the inventive method, so that the width tolerances can be better met.

In addition to influencing the tension σ for influencing the width of the rolling stock 5, it is also possible to adjust the crowning of a working and / or a supporting roll of the rolling stand 7 as a function of the width error e. For this example, the control scheme after Fig. 7 used. The difference to the scheme 4b consists in that the _{width error} e is additionally _fed to a controller R _Balligk for influencing the crowning of a working and / or support roller of the roll stand 7, which influences the crowning of the roll via the manipulated variable u ₂ . Thus, the controlled system G by two manipulated variables u ₁ , u ₂ influenced, wherein the controlled variable is the width B _is the rolling stock 5 after the second unit 4 (specifically, the roll stand 7). The manipulated variable u ₁ corresponding to the manipulated variable u from the 4b , As in Fig. 1 seen, the actual width B _is measured by the width measuring device 16 at the output of the second unit 4 and the control loop are fed.

The Fig. 8 shows like that Fig. 1 a part of a cast-rolling composite plant with a continuous casting machine 1, a first unit 2 in the form of a pair of drive rollers 10, a second unit 4 in the form of a rolling stand 7 and in addition a third unit 17 in the form of another rolling stand 7. To achieve higher Extracting or holding forces, the first unit 2 could of course also include several drive rollers 10. The second unit 4 together with the third unit 17 forms the rough rolling of the cast-rolling composite system. In Fig. 8 the rolling stock 5 is discharged from the drive rollers 10 from the continuous casting machine 1 with a thickness of 90mm, then rolled in the second unit 4 to a thickness of 50mm, and finally reduced in the third unit 17 to a thickness of 30mm. The width of the strand after the mold 8 B _mold , the width of the strand in the drive roller 10 B _{drive roller} , the target width B _target and the width of the strand after exiting the second unit 4 - once without B _{aggregate 2} and once at application of B according to the invention _is process - are in FIG. 9 shown. The actual width of the rolling stock 5 or of the rolled product 12 is in turn measured immediately after the second unit 4 by the width measuring device 16. From the FIG. 9 shows that the actual width B _{actual of} the rolled product 12 remains much longer within the width tolerance by the application, so that the Ausbringverluste be reduced.

The rule scheme for the Fig. 8 and 9 is in FIG. 10 shown. In contrast to the control scheme after 4b the width error e = B _Soll -B _{Ist is used} to control a first train σ ₁ between the first 2 and the second unit 4 and to control a second train σ ₂ between the second 4 and the third unit 17, the resulting manipulated variables u ₁ , u ₂ interact with each other on the controlled system G. Optionally, both the gain factors K ₁ and K _{2 of} the reinforcing members 14, the boundaries of the limiting members 15 and the controller R _σ for the first branch for influencing the train σ ₁ and for the second branch for influencing the train σ ₂ can be chosen differently.

While the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1

continuous casting

2

first aggregate

3

roller table

4

second aggregate

5

rolling

6

transport direction

7

rolling mill

8th

mold

9

strand guide

10

capstan roller

11

casting speed

12

rolled products

13

Dead time

14

amplifier element

15

limiting member

16

width gauge

17

third aggregate

B

width

B _is

Actual width

B _target

Nominal width

B _kokille

Width of the strand at the exit from the mold

B _{drive roller}

Width of the rolled stock at the exit from the first

B _{unit 2}

aggregate

B ₁

first width

B ₂

second width

e

width error

G

controlled system

R

regulator

R _σ

Train controller

σ

train

t

Time

u, u1, u2

manipulated variable

Claims (13)

1. Method for altering the width of a strip-shaped rolled material (5), wherein the rolled material (5) passes uncut through a first unit (2) and a second unit (4 and the rolled material (5) is rolled in a rolling stand (7) in the first unit (2) and/or in the second unit (4), comprising method steps as follows:

   - producing the rolled material (5) with a first width B₁, wherein the rolled material (5) emerges from the first unit (2) with a width B = B₁, and the emerging rolled material (5) is transported to the second unit (4);

   - producing a transition piece of the rolled material (5), wherein the rolled material (5) emerges from the first unit (2) with the width B, where B₁ ≤ B ≤ B₂;

   - producing the rolled material (5) with a second width B₂, wherein the rolled material (5) emerges from the first unit (2) with the width B = B₂;

   characterised in that the crown of at least one working roll and/or at least one backing roll of the rolling stand (7) is set as a function of a width error e = B_setp-B between a setpoint width B_setp and the width B of the rolled material (5), wherein the crown is increased if e > 0 and the crown is reduced if e < 0.
2. Method according to claim 1, characterised in that the setting of the crown is effected in a controlled manner as a function of the width error e.
3. Method according to one of claims 1 to 2, characterised in that the setting of the crown is effected in a regulated manner as a function of the width error e, wherein the width B is the measured width B_actual of the rolled material (5) as it emerges from the second unit (4) or thereafter.
4. Method according to one of claims 1 to 3, characterised in that the setting of the crown takes into consideration the transport time of the rolled material from the first unit (2) to the rolling stand (7).
5. Method according to one of the preceding claims, characterised in that the setpoint width B_setp is either a step function H(t) or a ramp function R(t) from B₁ to B₂ or from B₂ to B₁.
6. Method according to one of the preceding claims, characterised in that the first unit (2) is a mould of a casting machine, e.g. a bow-type continuous casting machine (1) or a two-roll casting machine.
7. Method according to one of claims 1 to 6, characterised in that the first unit (2) is a rolling stand (7), e.g. a rolling stand (7) of a roughing mill train.
8. Method according to one of the preceding claims, characterised in that the rolled material (5) is transported from the first unit (2) on a roller table (3) to the second unit (4).
9. Method according to one of the preceding claims, wherein the rolled material (5) emerging from the first unit (2) is transported in the direction of transport (6) to the second unit (4) while maintaining a tension σ = σ_normal, characterised in that the tension σ on the rolled material (5) between the first unit (2) and the second unit (4) is set as a function of the width error e = B_setp-B, wherein the tension σ is increased to σ > σ_normal if e < 0.
10. Method according to claim 9, characterised in that the tension σ is reduced to σ < σ_normal if e > 0.
11. Method according to one of claims 9 to 10, characterised in that the setting of the tension σ is effected in a controlled manner as a function of the width error e.
12. Method according to one of claims 9 to 10, characterised in that the setting of the tension σ is effected in a regulated manner as a function of the width error e, wherein the width B is a measured width B_actual of the rolled material (5) as it emerges from the second unit (4).
13. Method according to one of claims 9 to 12, characterised in that the setting of the tension σ is effected on the basis of a mathematical necking model for the rolled material under tension o.

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