EP1543900B1 - Method and continuous casting machine for calibrating and controlling roll gaps of guide roller segments or driving rolls when casting liquid metals, especially liquid steels - Google Patents

Abstract

In a process to set segmented (7) the roller gaps (6) for a continuous steel casting process, a calibration plug (22) is inserted in the gap between the rollers and advances through the line. The roller displacement is logged via pistons (11) and sensors. The information is logged and the roller position adjusted prior to commencement of the steel casting process.

Description

The invention relates to a method and a continuous casting machine for setting and controlling the roll gaps of support roll segments or pairs of drive rolls in a continuous casting machine for casting liquid metals, in particular liquid steel materials, wherein the roll gap between two opposing support rollers of the fixed side and the loose side via paired hydraulic piston Cylinder units are measured and controlled with integrated electronic position or position encoders, wherein the measured values are evaluated within a control loop of the control for the forces to be transmitted to the casting strand in time segments.

Such a method is from the EP 1 062 066 B1 known. The paired piston-cylinder units are set to prevent occurring bulges, which can lead to damage to the support roller segments. For this purpose, excessive force effects are avoided in such a way that the piston-cylinder units are adjusted both position-controlled and force-controlled and can be switched from pressure-controlled operation to the force-controlled operation when the pressure in the respective piston-cylinder unit reaches a limit.

In order to achieve a static certainty of the forces exerted by the piston-cylinder units, it has also been proposed ( DE 196 27 336b C1) in a support roller segment with four servo-piston-cylinder units, two adjoining servo-piston-cylinder units hydraulically linked to each other and set the other servo piston-cylinder units independently However, the known designs do not consider all circumstances of the basic setting the roll nip and the controllability during the casting operation.

The position-controlled piston-cylinder units of the support roller segments are adjusted on an alignment stand in a remote workshop by means of a so-called Kalibrierbramme over the total length of all support roller pairs and transmitted the measured values of the calibration for the relevant support roller segment to the control of the continuous casting. The roller gaps may deviate again after installation in the framework of the continuous casting device, so that a roller gap testing device is precautionary driven through the roller gap path. The calibration slab can also be lowered from above into the roller gap path by means of a crane and then the piston-cylinder units of all support roller segments are adjusted over the total length of all roller pairs.

The object of the invention is to carry out the roller gap adjustment of individual support roller pairs largely separately in smaller steps and thereby obtain more accurate results, so that the roller gap path as a whole can be set more accurately.

The stated object is achieved in that a at least one pair of rollers detecting calibration moved through the open roller gap and clamped during the transport movement between two opposing support rollers for a short time and each stored the clamping positions associated positions of the piston-cylinder units metrologically and after a nominal-actual value comparison, the positions of the piston-cylinder units are corrected before casting start or in a casting pause. As a result, the basic adjustment procedure is simplified without special aids and a higher accuracy of the roller gap path is achieved by the smaller measuring steps. The calibration of the support rollers is no longer performed in the workshop, but in the stationary device. The method can also be applied to individual support roller pairs. For an in-line measurement a maximum of two existing pairs of rollers are required.

One embodiment is that, in roller pairs mounted in support roller segments, the measurements are made between successive support roller segments on a calibration piece covering a maximum of three pairs of rollers. For in-line measurement of support roller segment transitions and for averaging in the determination of measured values, it is advantageous to extend the measurement method to a maximum of three roller pairs.

Another measure is that the calibration piece is moved in the roller gap path either from top to bottom or from bottom to top. As a result, measurement times can be integrated independently of plant downtime in the production time or during the Gießstartablaufs.

An accuracy-assurance measure is that based on the vertical distance of the lowermost pair of rollers up to a (in height) middle pair of rollers in a support roller segment, the upper piston-cylinder unit (of two per support roller segment superimposed pairs) to a fixed value is position-controlled. The advantage is an even more accurate measurement result.

It is further proposed that, based on the respective vertical distance between the measured values of the position of the lower piston-cylinder unit are stored in the calibration roller and the first pair of rollers on the fixed side in the support roller segment. As a result, a dependent on the position of the piston-cylinder unit and thus more accurate measurement result can be achieved.

In this sense, it is further provided that from a middle pair of rollers to the first pair of rollers of a support roller segment, the lower piston-cylinder unit is controlled to a fixed value in position.

A further formation of outstanding measuring points is achieved in that, based on the vertical distance between the calibration piece and the last support roller pair on the fixed side, the respective position in the force-controlled, upper piston-cylinder unit of a support roller segment are stored with their measured values.

The device for carrying out the method is based on a prior art, with a continuous casting machine for liquid metals, in particular for liquid steel materials, with the casting strand leading and / or supporting support roller segments or pairs of drive rollers, each paired, upper and lower hydraulic piston-cylinder Units with integrated electronic Wegoder position encoders for adjusting the roller gap between at least two mutually opposite support rollers of the fixed side and the Losseite, wherein the successive support roller pairs form a roller gap and the measured values within a control loop of the control for the cast strand in time to be transmitted forces be used.

The stated object is achieved according to the invention in that a calibration piece, which is attached to a traction means, from support roller pair to support roller pair in Rollenspaltweg movable and between a support roller pair by means of the respective Piston-cylinder unit is clamped and the associated positions of the piston-cylinder units are metrologically stored and controlled before casting start or in Guiießpausen. This results in measuring results in smaller steps and therefore more accurate.

The traction means may consist of a starter train according to another feature.

For the transitions between two support roller segments is also provided that the calibration piece is tuned in its length in the roller gap path successive maximum of three support roller pairs.

It is also advantageous that the shape and dimensions of the calibrating piece is adapted to the continuous casting machine type and the starting line used (starting bolt or link chain).

Finally, it is provided that the measured value recording, the assignment and the evaluation of the measurement results in a central computer in the switching house.

In the drawing Auführungsbeispiele of the invention are shown, which are explained in more detail below.

Fig. 1

eine Seitenansicht einer Dünnbrammen-Stranggießmaschine im Schnitt,

Fig. 2

eine schematisierte Seitenansicht eines geraden Senkrecht-Stützrollensegmentes mit einem Kalibrierstück, als Blockschaltbild zusammen mit einer oberen und einer unteren Kolben-Zylinder-Einheit,

Fig. 3

dieselbe Seitenansicht wie Fig. 2 mit einem alternativen Kalibrierstück und

Fig. 4

die Seitenansicht wie die Fig. 2 und 3 als Blockschaltbild innerhalb der gesamten Steuerungseinrichtung der Stranggießmaschine.

Show it:

Fig. 1

a side view of a thin slab continuous casting in section,

Fig. 2

6 is a schematic side view of a straight vertical support roller segment with a calibration piece, as a block diagram together with an upper and a lower piston-cylinder unit,

Fig. 3

the same side view as Fig. 2 with an alternative calibration piece and

Fig. 4

the side view like that Fig. 2 and 3 as a block diagram within the entire control device of the continuous casting machine.

In Fig. 1 the liquid steel material 1 flows from a distribution vessel 2 into an oscillating continuous casting mold 3 and is cooled in a spraying chamber 4 to such an extent that an all-round strand shell surrounds the still liquid core. The cast casting strand 5 forms a thin slab 5a with a rectangular cross-section, which is guided and / or supported on the further path through a roller gap 6 in a plurality of successively following support roller segments 7 and further cooled. Each support roller segment 7 consists of (idling) support rollers 8a and 8b, which form a fixed side 9 of non-adjustable support rollers 8a and a loose side 10 for adjustable to different cast strand thickness support rollers 8b. The adjustability results from piston-cylinder units 11 and 12, which are arranged in pairs over the strand width ( Fig. 2 to 4 ).

In the further course of the piston-cylinder units 11, 12 the roller gap 13 by means of position sensors 14 via a control circuit 15 to the respective, for example. By shrinking changing roller gap 13 and the applied support forces. In the embodiment of Fig. 1 the cast strand 5 is formed via a bending driver 16, Biegerollenpaare 17 by means of a Biegerichttreibers 18 in the horizontal.

When starting the casting process, the casting strand 5 is pulled out by means of a Anfahrbolzens 19, which may consist of sheet-continuous casting from a limbs-Anfahrstrangkette and pulled out by means of a roller drive 20 and parked after uncoupling by the bending driver 16 in a quiver 21 for a later use.

The procedure for setting and controlling the roller gap 6 (FIG. Fig. 2 ) operates such that a at least one pair of rollers 8a, 8b detecting calibration piece 22 is moved through the open Rollenspaltweg 13 and clamped during transport between each two opposing support rollers 8a, 8b for a short period of time (outside the casting or before the casting start) and the respectively associated with the clamping positions positions of the piston-cylinder units 11, 12 stored metrologically and after a desired-actual value comparison 23, the determined position of the piston-cylinder units 11, 12 are corrected.

When stored in support roller segments 7 roller pairs 8a, 8b, the measurements between successive support roller segments 7 on a maximum of three pairs of rollers 8a, 8b overlapping calibration piece 22a made ( Fig. 3 ).

According to Fig. 2 is, based on the vertical distance 24 of the lowermost pair of rollers 25 to a middle pair of rollers 26 in a support roller segment 7, the upper piston-cylinder unit 11 is controlled to a fixed value in this position.

In Fig. 3 is stored on the vertical distance 24 between the calibration piece 22 or 22a and the first pair of rollers 27 in the support roller segment 7, the measured values of the position of the lower piston-cylinder unit 12 in a computer 30 (see also Fig. 4 ).

Analogous to the procedure described so far, the lower piston-cylinder unit 12 is regulated to a fixed value in the position of the middle roller pair 26 to the first roller pair 27 of a support roller segment 7.

Likewise, based on the vertical distance 24 between the respective calibration piece 22 or 22a and the lowermost support rollers 8a on the fixed side 9, the respective position in the force-controlled, upper piston-cylinder unit 11 of a support roller segment 7 is stored with the associated measured values.

That in the Fig. 2 to 4 shown calibration piece 22 or 22a is attached to a traction means 28, which consists in the embodiment of a starter strand in the form of a starting pin 19. The calibration piece 22, 22a is moved from the support roller pair 8a, 8b to the next pair of support rollers 8a, 8b within the roller gap path 13 and is clamped between the opposing support rollers 8a, 8b by the respective piston-cylinder unit 11 or 12. The position of the piston-cylinder units 11 or 12 thus obtained is stored in a positionally controlled manner and controlled in a force-controlled manner before the casting start or during casting pauses.

In addition, the layer 31 of the calibration piece 22; 22a held, for example. Via a measuring roller or a driven roller in the pulse path 13 with a pulse and the data are passed into an evaluation unit 29.

The calibration piece 22 or 22a is tuned in its length to a minimum of two in the roller gap 13 successive support rollers 8a, 8a and 8b, 8b.

The shape and dimensions of the calibrating piece 22, 22a are adapted to the continuous casting machine type as well as to the starting strand used as traction means 28.

According to Fig. 4 are shown in the control loop 15, the desired position or the desired force of the upper piston-cylinder unit 11 and the lower piston-cylinder unit 12. The respective actual position is determined by the position sensor 14. Actual positions and target positions are each in the evaluation unit 29, the the computer 30 is connected, entered, in which the position 31 of the calibration piece 22, 22 a is taken into account for each measurement.

In a setpoint-actual value comparison 23 and in the central computer 30 or the evaluation unit 29, the calculation of the instantaneous, relative to the default setting (position 31 of the calibration 22, 22a) to be made correction 32 of the respective piston-cylinder unit 11th , 12 related to the position 31 of the Kalibrierstükkes, position-controlled before the casting start or in pouring breaks and force-controlled during the casting operation.

LIST OF REFERENCE NUMBERS

1

(liquid) steel material

2

distribution vessel

3

oscillating continuous casting mold

4

injection chamber

5

cast strand

5a

thin slab

6

nip

7

Support roller segment

8a

supporting role

8b

supporting role

9

fixed side

10

loose side

11

(upper) piston-cylinder unit

12

(lower) piston-cylinder unit

13

Rollenspaltweg

14

locator

15

loop

16

bending driver

17

bending rolls

18

Bending directional driver

19

Anfahrbolzen

20

Roller drive for starting bolts

21

quiver

22

calibration piece

22a

Calibration piece for more than two support rollers

23

Target actual value comparison

24

vertical distance

25

lowest pair of rollers

26

middle pair of rolls

27

first pair of roles

28

traction means

29

Evaluation unit

30

central computer

31

Location of the calibration piece

32

correction

Claims (12)

1. Method for basic setting and controlling of the roller gap (6) of support roller segments (7) or drive roller pairs in a continuous casting machine for casting liquid metals, particularly liquid steel materials (1), in which the roller gap (6) between two mutually opposite support rollers (8a; 8b) of the fixed side (9) and the movable side (10) is measured and regulated by way of paired hydraulic piston-cylinder units (11, 12) with integrated electronic travel or position transmitters (14), wherein the measurement values are evaluated within a regulating circuit (15) of the control for the forces to be transmitted to the cast strip (5) in time sections, characterised in that a calibrating member (22; 22a) engaging at least one roller pair (8a; 8b) is moved through the open roller gap path (13) and during the transport movement is clamped for a short time between each two mutually opposite support rollers (8a; 8b) and the positions, which are associated with each of the clamping settings, of the piston-cylinder units (11; 12) are stored as measurements and after a target/actual value comparison (23) the positions of the piston-cylinder units (11; 12) are corrected for start of casting or in a pause in casting.
2. Method according to claim 1, characterised in that in the case of roller pairs (8a; 8b) mounted in support roller segments (7) the measurements between successive support roller segments (7) are undertaken at a calibrating member (22a) covering a maximum of three roller pairs (8a; 8b).
3. Method according to one of claims 1 and 2, characterised in that the calibrating member (22; 22a) is moved in the roller gap path (13) either from above to below or from below to above.
4. Method according to one of claims 1 to 3, characterised in that referred to the vertical spacing (24) of the lowermost roller pair (25) from a middle roller pair (26) in a support roller segment (7) the upper piston-cylinder unit (11) is position-regulated to a fixed value.
5. Method according to one of claims 1 to 3, characterised in that the measurement values of the position of the lower piston-cylinder unit (12) are stored referred to the respective vertical spacing (24) between the calibrating member (22; 22a) and the first roller pair (27) on the fixed side (9) in the support roller segment (7).
6. Method according to one of claims 1 to 5, characterised in that the lower piston-cylinder unit (12) is regulated to a fixed value in position from a middle roller pair (26) to the first roller pair (27).
7. Method according to one of claims 1 to 6, characterised in that the respective position in the force-regulated upper piston-cylinder unit (11) of a support roller segment (7) is stored, together with its measurement values, referred to the vertical spacing (24) between the calibrating member (22; 22a) and the last support roller pair (8a) on the fixed side (9).
8. Continuous casting machine for liquid metals, particularly for liquid steel materials (1), with support roller segments (7) or drive roller pairs, which guide and/or support the cast strip (5) and which each comprise paired upper and lower hydraulic piston-cylinder units (11; 12) with integrated electronic travel or position transmitters (14) for setting the roller gap (6) between at least two mutually opposite support rollers (8a; 8b) of the fixed side (9) and the movable side (10), wherein the successive support roller pairs (8a; 8b) form a roller gap path (13) and the measurement values are used within a regulating circuit (15) of the control for the forces to be transmitted to the cast strip (5) in time sections, characterised in that a calibrating member (22), to which a tension means (28) is fastened, is movable from support roller pair (8a, 8b) to support roller pair (8a; 8b) in the roller gap path (13) and is clamped between a support roller pair (8a; 8b) by means of the respective piston-cylinder unit (11; 12) and the positions, which are connected therewith, of the piston-cylinder units (11; 12) are stored as measurements and can be controlled before the start of casting or in pauses in casting.
9. Continuous casting plant according to claim 8, characterised in that the tension means (28) consists of a start strip (19).
10. Continuous casting plant according to one of claims 8 and 9, characterised in that the calibrating member (22; 22a) is matched in its length to a maximum of three support roller pairs (8a; 8b) successive in the roller gap path (13).
11. Continuous casting plant according to one of claims 8 to 10, characterised in that the shape and dimensions of the calibrating member (22; 22a) are matched to the continuous casting plant type and the start strip (19) employed.
12. Continuous casting plant according to one of claims 8 to 11, characterised in that the measurement value recordal, the association and the evaluation of the measurement results are carried out in a central computer (30) in the control station.

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