EP2809465B1 - Method for the continuous casting of a metal strand in a continuous casting installation and a continuous casting installation - Google Patents

Description

The invention relates to a method for continuously casting a metallic strand in a continuous casting installation, in which the metal formed into a casting machine with molten core is vertically ejected from a mold in a casting machine, wherein the slab is guided in the conveying direction behind the mold through a number of segments, wherein each segment comprises a number of segmented rollers adapted to make contact with the slab surface, a number of segmented rollers being lifted from the slab surface in the area in front of the casting machine end or not being installed in provided receivers so that the contact between the slab and the segmented roller is interrupted is not given. Furthermore, the invention relates to a continuous casting plant.

The generic production of a strand is well known in the art. The cast strand, ie the slab, leaves the mold and is still molten in the interior. Along the pouring arc, the slab is bent from the vertical to the horizontal, using a number of casting arc segments. Each casting arc segment has a number of segment rolls which contact the slab in pairs on opposite sides.

The prior art is on the FIGS. 1 to 3 pointed. Fig. 1 shows a casting machine as part of a continuous casting in the side view. In Fig. 2 is the course of the temperature of the mold to an oven, which is downstream of the casting machine, shown.

In Fig. 1 It can be seen that the continuous casting plant 1 comprises the casting machine 2, which comprises a number - in the present case eight illustrated - casting arc segments 4, 5, 6, 7, 8, 9, 10 and 11, which form a pouring arc 3. The mold and the first three Gießbogensegmente are not shown. Along the pouring arc 3, the cast slab is conveyed to the casting machine end 14 in the conveying direction F and thereby deflected from the vertical to the horizontal.

In each Gießbogensegment 4, 5, 6, 7, 8, 9, 10, 11, a number of pairs of segment rollers 12 and 13 are mounted, between which the slab is conveyed through.

The casting machine length (from the mold to the casting end 14) is usually determined so that at maximum mass flow (corresponding thickness or cross section of the slab times casting speed) the solidification of the cast strand still within the last Gießbogensegments (ie present in the casting arc segment 11) takes place. The resulting temperature profile is in Fig. 2 illustrated, here by the example of a 16.4 m long Bogengießanlage. Shown are the core temperature T _K , the surface temperature T _O (on the underside of the slab) and the average value of the temperature T _M over the slab thickness when passing through the casting machine until it enters the roller hearth furnace located behind. Indicated is the casting machine end 14 and the stove beginning 19.

The average outlet temperature of the thin slab from the casting machine is higher than 1,200 ° C here. Also during further transport to the furnace, the slab loses its free environment and rolls, etc., still about 70 ° C at temperature. Due to the high mass flow, however, the temperature level at the inlet to the furnace is sufficiently high (here: 1,166 ° C).

It should be noted that the solidification of the slab takes place just before the end of the casting machine 14; the position is designated by 23.

However, the continuous casting plant is not always operated with the optimum conditions or with maximum casting speeds. Casting technology reasons (eg surface quality, crack prevention, casting stability) also require lower casting speeds depending on the product to be cast. A casting machine can and must be able to adjust the casting speeds flexibly. Also, for casting technology reasons, the strand cooling can not be arbitrarily adapted to the lower mass flow. At lower mass flow, therefore, the cast strand solidifies far within the continuous casting, which is evident Fig. 3 results. Here, again, the course of the temperature of the mold to the furnace is shown, but now at - in relation to Fig. 2 - lower casting speed. The Durcherstarrungsort the slab is again indicated at 23 and is far in front of the casting machine end 14. After the solidification loses the strand in its further course through the continuous casting in the example, additionally about 150 ° C (see .DELTA.T ₁ ) to the casting machine end 14th As a result of the low mass flow, the temperature loss between the end of the continuous casting machine 14 and the beginning of the furnace 19 is relatively high (see ΔT ₂ : in the example about 100 ° C), so that in the present case, the mean inlet temperature in the furnace only about 987 ° C is.

Consequently, there are large energy losses in the slab during early solidification within the continuous casting and during transport to the furnace at low mass flow.

A method of the type mentioned is from the DE 76 13 430 U1 known. Other solutions reveal the GB 1 603 428 A , the WO 2007/137759 A1 , the WO 2007/073841 A1 , the DE 10 2010 022 003 A1 and the EP 0 287 021 A2 ,

The invention has for its object to provide a method and a continuous casting, with which it is possible to reduce said energy losses in a simple and efficient manner, so that even with changing casting speed always optimal process conditions can be maintained. Thus, an energetically optimized mode of operation should be possible, which can be set at a predetermined casting speed.

The solution of this problem by the invention is according to the method characterized in that between the slab surface and the at least one from the slab lifted or uninstalled segment roller a thermal insulation element is introduced. Preferably, it is provided that the slab is guided in the conveying direction behind the mold along a casting arc through a number Gießbogensegmente and deflected in the horizontal, each Gießbogensegment having a number of segmented rollers, which are designed to make contact with the slab surface, wherein along the casting arc in A number of segmented rolls are lifted from the slab surface before the end of the casting machine or are not installed in intended receptacles.

This introduction of the Dämmelements can be done by horizontal insertion from the side of the slab.

The thermal insulation elements can be permanently installed between spaced support rollers or driver rollers, in particular in front of one or both sides of the slab or slab edges.

Preferably, a simulation calculation is carried out by means of a calculation model, the position of the sump tip being determined at least on the basis of the casting speed and the slab geometry, but possibly also on the basis of further parameters, the lifting off of segmented rolls on the basis of the simulation calculation taking place so that the lifting off for a defined section of the Casting arc takes place. Specifically, it can be provided that the Gießbogensegmente, which lie in the conveying direction behind the calculated Sumpfspitze, ascended and optionally provided with a thermal insulation element.

The Gießbogensegmente are usually provided with cooling means for cooling the slab, in which case the cooling capacity can be reduced or brought to zero at least on a number of Gießbogensegmente.

The slab can be supported at least in the region of the casting arc segments with lifted segment rolls by preferably driven support rollers, so that despite the out of contact brought support rollers a sufficient guidance and a functional transport of the slab is given. Alternatively, drive roller pairs or pinch rollers can be installed at certain intervals.

The lifted segment roles and / or the radiant heat of the slab exposed support rollers are preferably rotationally driven.

The proposed insulating effect in the continuous casting is preferably combined or supplemented with insulation measures that are performed behind the continuous casting.

Behind the casting machine is usually - in addition to other facilities - arranged a furnace, wherein at least one thermal insulation element for thermal insulation of the slab can be arranged in the region between the casting machine end and the beginning of the oven. In this case, it can be provided that the at least one thermal insulation element is retracted only temporarily into the region of the slab to its thermal insulation.

Preferably, it is further provided that the at least one thermal insulating element is retracted into the region of a pair of scissors and / or in the region of an inline scaffold and / or in the region of a cold string removal.

Thus, an improvement of the material properties - also on the surface and the edges of the slab - by increasing the minimum temperature before re-heating in the oven (or in the induction heating) by means of insulating elements in the continuous casting and / or behind the continuous casting can be achieved.

The proposed continuous casting for continuous casting of a metallic strand having a casting machine in which the slab-shaped metal can be applied with still molten core from a mold vertically, wherein in the conveying direction behind the mold a pouring arc is arranged with a number Gießbogensegmente, with the the slab can be deflected into the horizontal, wherein each Gießbogensegment has a number of segmented rollers, which are designed to make contact with the slab surface, according to the invention is characterized in that along the casting arc in the region before the casting end a number of segment rollers are provided with adjusting means to to be able to lift the segmented roll from the slab surface, wherein at least one movable thermal insulating element is present, which in a passive position outside the Gießbogensegments and in an active position within the Gießbogensegments and between the lifted segment roll and the slab can be placed.

The at least one movable thermal insulation element can be arranged horizontally and transversely to the conveying direction of the slab by the adjusting means.

The thermal insulation elements used are known as such in the prior art. These solutions can be used. It is this particular on the EP 0 198 595 B1 , on the EP 0 005 340 B1 , on the DE 1 452 102 A1 and on the EP 0 042 656 B1 pointed.

With the proposed approach, an increase in the temperature of the slab behind the casting machine and a higher furnace inlet temperature is achieved, without having to drive this an additional energy cost.

• Die Segmentrollen sollen bei Bedarf, das heißt wenn die (Aus-)Kühlung der durcherstarrten Bramme vermindert werden soll, vom Strang abheben, das heißt in den Rollensegmenten, in denen der Strang bereits durcherstarrt ist. Hierdurch wird der den Strang kühlende Kontakt der Rollen vermieden. Zweckmäßiger Weise sind dabei die Rollen angetrieben, um eine einseitige Erwärmung und Deformation der Rollen zu vermeiden. Dies gilt insbesondere, wenn die Rollen ungeschützt, das heißt ohne Dämmung, längere Zeit der Brammenstrahlung ausgesetzt sind.

In order to reduce the cost of re-heating the slab in the furnace and thus save energy costs, the following measures are proposed in the field of continuous casting (including the further transport to the furnace):

• If necessary, that is, when the cooling of the solidified slab is to be reduced, the segmented rolls should lift off from the strand, that is to say in the roll segments in which the strand is already solidified. As a result, the strand cooling the contact of the rollers is avoided. Conveniently, the rollers are driven in order to avoid unilateral heating and deformation of the rollers. This is especially true if the roles unprotected, that is without insulation, a long time the slab radiation are exposed.

With an extended lifting of the segmented rollers from the strand, it becomes possible to insert an insulating hood (thermal insulation element) between the strand and the segmented rolls. The insulation hood heats up in continuous operation to approximately strand surface temperature and thus significantly reduces the temperature loss.

The strand is supported in this case only by individual preferably driven strand rolls (support rollers).

In the continuous casting plant, the segment cooling in the area from the mold to the through solidification of the strand is minimized within the technologically permissible limits. Here, a two-material cooling offers, which has a larger adjustment range of the cooling effect; but it is also at least partially a dry pouring possible.

Another measure is the deactivation of the segment cooling in the solidified area to the casting machine end.

• Gießgeschwindigkeit, Brammendicke bzw. Brammengeometrie, Materialkonstanten, Einstellungen bei der Kokillenkühlung, die Kühlwirkung der Segmentkühlung, die Kühlwirkung an den Segmentrollen und an der sonstigen Umgebung.

For controlling the method, a mathematical model is preferably used. This calculation model describes the cooling of the strand within the continuous casting plant and the segment in which the strand solidifies safely. Among other things, the calculation model takes into account the following parameters:

• Casting speed, slab thickness or slab geometry, material constants, settings in the mold cooling, the cooling effect of the segment cooling, the cooling effect on the segment rolls and in the other environment.

The calculation can take place as a setup before the start of casting or dynamically during the casting process. Depending on the result of the simulation, it is determined which segments are driven up. If the mass flow changes during casting, individual segments can be opened or closed again, resulting in a flexible change of the strand length.

It can be provided that entire segments are adjusted as described; Alternatively, however, it is also possible for segment groups or separately individual segment rolls or segment roll pairs to be adjusted.

• Jeder freie Bereich kann mit ortsfesten oder beweglichen Dämmhauben (thermischen Dämmelementen) versehen werden.

Between the casting machine and the subsequent furnace, the following measures can have an advantageous effect in the sense of the task according to the invention and supplement the desired effect:

• Each free area can be provided with fixed or movable insulating covers (thermal insulation elements).

This can be done first in the field of cold-string disposal. For this purpose, after the removal of the cold leg of the "gallows" pivoted high and retracted into the space a Dämmhaube.

A corresponding thermal insulation is also possible between the roller table rollers.

Similarly, a thermal insulation in the area of the scissors frame and the shear blade can be done. To cut the thermal insulation hoods can be pivoted out of the cutting area and then swung back again. Accordingly, this area can not be insulated at the slab head and at the end of the slab. However, these temperature losses or temperature differences can be compensated in the oven by targeted torch mode or more efficiently by a small inductive heating, which acts on these colder areas. The temperature differences at the end of the slab are largely compensated by rapid transport into the furnace.

Also in the area of slab cleaning a thermal insulation is possible. This area can be used if the slab cleaning is not used and is swung up.

It is also advantageous to minimize the distance between the end of the casting machine and the beginning of the oven.

The proposed measures are preferably used on a thin slab Bogengießanlage used. Of course, however, they are also suitable for other continuous casting plants, in particular for vertical casting plants or for conventional thick slab casting plants.

In a vertical continuous casting preferred insulation measures are already carried out in the vertical and arch portion behind the continuous casting.

Instead of a pair of scissors and an oven behind the casting machine can also be an inline rolling mill with scissors arranged behind it and in the course of a furnace (or an inductive heater) installed behind the caster. For the area of the inline rolling stand, the same insulation measures described above apply.

• Es erfolgt ein nur minimaler Temperaturverlust im Bereich der Gießmaschine und auf der Transportstrecke dahinter. Es kommt zu einer Verminderung von Heizenergie im nachfolgenden Ofen (zumeist: herkömmlicher Rollenherdofen).

With the proposed procedure and apparatus configuration, it is possible to achieve the following energetic advantages:

• There is only a minimal loss of temperature in the casting machine and on the transport route behind it. There is a reduction of heating energy in the subsequent furnace (usually: conventional roller hearth furnace).

If in this way 100 ° C Brammentemperaturerhöhung be achieved at the entrance of the slab in the oven, there is a saving of about 36 kWh / t gas energy in the oven, that is about 1.10 € / t at a gas price of 0.03 € / kWh.

It results in an advantageous manner a higher furnace inlet temperature as an energetic average but also on the surface and especially on the slab edges.

It is possible to improve and ensure the material properties, especially for higher quality materials even at low mass flow, which may be technologically required.

The segment roller wear will also be reduced by the proposed measures, especially in the back of the caster.

As a result of a higher average inlet temperature in the oven, it is further possible to shorten the oven length somewhat.

Finally, the scissor load decreases or the scissors can be made smaller.

Fig. 1

in der Seitenansicht eine Gießmaschine als Bestandteil einer Stranggießanlage gemäß dem Stand der Technik,

Fig. 2

nach dem Stand der Technik den Verlauf der Temperatur von der Kokille bis zu einem Ofen, der der Gießmaschine nachgeschaltet ist, wobei eine erste, hohe Gießgeschwindigkeit gegeben ist,

Fig. 3

nach dem Stand der Technik den Verlauf der Temperatur von der Kokille bis zum nachgeschalteten Ofen, wobei eine zweite, verminderte Gießgeschwindigkeit gegeben ist,

Fig. 4

in der Seitenansicht die Gießmaschine, die nunmehr erfindungsgemäß ausgestattet ist und erfindungsgemäß betrieben wird,

Fig. 5

den Bereich der Stranggießanlage zwischen Gießmaschinenende und Ofen, der erfindungsgemäß ausgestattet ist und erfindungsgemäß betrieben wird, und

Fig. 6

den Verlauf der Temperatur von der Kokille bis zum nachgeschalteten Ofen, wobei die zweite, verminderte Gießgeschwindigkeit gegeben ist, wobei das erfindungsgemäße Verfahren eingesetzt wird.

In the drawings, embodiments of the invention are shown. Show it:

Fig. 1

in side view, a casting machine as part of a continuous casting plant according to the prior art,

Fig. 2

according to the prior art, the course of the temperature of the mold to a furnace, which is downstream of the casting machine, wherein a first, high casting speed is given,

Fig. 3

according to the prior art, the course of the temperature from the mold to the downstream furnace, wherein a second, reduced casting speed is given,

Fig. 4

in the side view of the casting machine, which is now equipped according to the invention and is operated according to the invention,

Fig. 5

the range of continuous casting between casting end and furnace, which is equipped according to the invention and operated according to the invention, and

Fig. 6

the course of the temperature from the mold to the downstream furnace, wherein the second, reduced casting speed is given, wherein the inventive method is used.

In Fig. 4 is a continuous casting 1 indicated, in which case the casting machine 2 is shown the same. For construction and operation is to the above embodiment Fig. 1 Referenced, which apply analogously here. What is new here is that it works with a casting speed that is reduced to such an extent that, without further measures, the sump tip is no longer in the area of the casting machine end 14, but instead - as in Fig. 3 shown - in the middle region of the casting machine. This would have the negative consequences, as related to Fig. 3 have been carried out above.

In order to prevent this, it is now provided according to the invention that a number of segment rollers 12 and 13 are lifted off the slab surface along the casting arc 3 in the area in front of the casting machine end 14. The contact between segment roller and slabs is thus interrupted. This has, first of all, the consequence that the cooling effect produced by the surface contact between the segmented roll and the slab does not occur and consequently the slab cools less strongly along its course to the casting machine end 14.

Furthermore, the segment rollers are raised or lowered in the direction normal to the slab surface so far that a thermal insulation element 15 or 16 can be introduced between the slab surface and the segment rollers 12, 13 lifted off the slab. Said insulation elements 15, 16 have been inserted laterally horizontally in the space created between the slab and segment roller 12, 13.

As a result, the slab can now cool much less than it would without the measure.

To give the slab despite lifted or lowered segment roller 12, 13 nevertheless a sufficient guidance, are in the Gießbogensegmenten preferably driven support rollers 17 are arranged. Accordingly, the strand is supported only by some support rollers 17. In the embodiment according to FIG. 4 the last three or four Gießbogensegmente 8, 9, 10, 11 have been adjusted accordingly.

In the present case, as it later in Fig. 6 can be seen, the cast strand already solidified approximately in the region of the casting arc segment 7. Accordingly, the following Gießbogensegmente 8, 9, 10 and 11 are ascended and provided with insulation elements 15, 16. This measure can be done above and below the slab, but possibly also only on one side.

A lateral insulation in the direction of the slab edges is provided. This may be attached to the insulating elements 15, 16 or have separate adjustment mechanisms. The lateral insulation is in Fig. 4 but not shown.

The extended lifting or lowering of the segment rollers is done for example by means of a long-stroke hydraulic cylinder 27, which in the embodiment according to Fig. 4 supported on the frame 28. As adjustment can also be used a mechanical adjustment or a pneumatic cylinder.

If the casting conditions are such that one or more casting segments or segment regions are not used for an extended period of time, said casting segments can optionally be advantageously prepared in such a way that the insulation is firmly installed. Again, as in Fig. 4 illustrated, the cast strand supported by spaced support rollers or drive rollers and installed in intermediate areas above and / or below and optionally also laterally a fixed insulation. Accordingly, a lateral retraction and extension of the insulation occurs in this case. Also, an extended employment of segmented rollers in the direction of the slab to or away from this does not take place here or the segment rolls are not present in the area of the insulation from the beginning.

In Fig. 5 It can be seen that thermal insulation measures are also taken in the region between the casting machine end 14 and the furnace beginning 19 of the subsequent furnace 18 in order to keep the slab warm at the furnace inlet. Thermal insulation elements 20, 21 and 22 are provided which, in a manner analogous to the insulation elements 15 and 16, hinder the release of heat from the slab to the environment and thus ensure that the slab remains warm.

In the area of slab cleaning 24, a swiveling insulating hood 20 is provided. The pivoting can take place when the spray bar of the slab cleaning 24 is not active and swung up.

Thermal insulation elements 21 are also present in the region of the scissors 25. The pivot arrows on the insulating elements 21 indicate the direction of movement, in which the insulating elements 21 are pivoted to either get into their active position (for thermal insulation) or in their passive position (for cutting the slab).

Also in the field of cold strand disposal immediately in front of the furnace 18, a thermal insulation element 22 is present. The gallows 26 for disposal of the dummy bar is indicated. After removal of the cold strand, the upper insulating element 22 can be pivoted into the position shown. The lower thermal insulation elements are presently designed as fixed insulation.

• Die sich ergebenden Temperaturverläufe für die Kerntemperatur T_K, den Mittelwert der Temperatur der Bramme T_M und der Oberflächentemperatur T_O auf der Brammenunterseite sind wiederum angegeben, wobei allerdings ergänzend und zu Zwecken des Vergleichs der Mittelwert der Temperatur T_M* als gepunktete Kurve eingetragen ist, die den Verlauf angibt, wie er sich ohne die erfindungsgemäßen Maßnahmen ergeben würde. Dass sich die temperaturmäßig höher liegende Kurve T_M ergibt, und nicht die Kurve T_M*, ist also das Resultat des Umstands, dass im eingetragenen Bereich D die beschriebenen Wärmedämm-Maßnahmen durchgeführt wurden.

These measures supplement the insulation effect in the continuous casting plant. Without insulation elements behind the continuous casting plant, part of the temperature effect which the continuous casting plant has produced would be lost again. In Fig. 6 It can be seen how the temperature profile with inventive design and procedure results:

• The resulting temperature profiles for the core temperature T _K , the average of the temperature of the slab T _M and the surface temperature T _O on the slab underside are again indicated, although supplementarily and for purposes of comparison, the mean value of the temperature T _M * is entered as a dotted curve indicating the course as it would result without the inventive measures. The fact that the temperature higher curve T _M results, and not the curve T _M *, so is the result of the fact that in the registered area D, the described thermal insulation measures were performed.

Accordingly, there is a higher inlet temperature of the slab upon entry into the oven 18 without additional energy.

In the proposed continuous casting and in the extended lifting of the segment roles increase the support lengths (frame) and the stroke of the adjustment etc. In order to optimize the setting accuracy of the segment roles, a calculation model and / or control algorithm is used, the rigidity of the segment, the segment frame and describes the influence of the adjusting elements (eg oil column) as a function of the contact pressure as well as the thermal change of the mechanical components (rollers, frame). Alternatively or additionally, force and displacement measuring sensors can also be used.

Furthermore, there are no fixed and Losseite for some segments in the continuous casting plant according to the invention, but both sides are adjusted. When opening and closing the segments they are positioned by means of encoders or driven optionally with the Verstellorgangen against stops (path limitation, quasi fixed side) and thus set the position defined.

The changed design of the segments can also have an influence on the exchange practice of the segments. When changing the segments, either the segments together with the frame 28 and adjusting members 27 can be changed, or the frame 28 is alternatively fixed and after removal of cross members, the segment rollers are removed for changing.

The segments or segment parts can be removed for changing across the slab transport direction to the side by the frame or lifted perpendicular to the slab transport direction.

LIST OF REFERENCE NUMBERS

1

continuous casting plant

2

casting machine

3

casting bow

4

Segment / casting arc segment

5

Segment / casting arc segment

6

Segment / casting arc segment

7

Segment / casting arc segment

8th

Segment / casting arc segment

9

Segment / casting arc segment

10

Segment / casting arc segment

11

Segment / casting arc segment

12

segment role

13

segment role

14

Gießmaschinenende

15

thermal insulation element

16

thermal insulation element

17

supporting role

18

oven

19

oven beginning

20

thermal insulation element

21

thermal insulation element

22

thermal insulation element

23

Place of Durcherstarrung

24

slabs cleaning

25

scissors

26

Gallows for disposal of the cold leg

27

Adjusting element (hydraulic cylinder)

28

frame

V

vertical

H

horizontal

F

conveying direction

T _K

core temperature

T _o

Surface temperature (slab underside)

T _M

Mean value of the temperature

T _M *

Mean temperature without thermal insulation measures

D

Range of thermal insulation measures

Claims (14)

1. Method for continuous casting of a metallic strip in a continuous casting plant (1), in which the metal formed into a slab and with still molten core is discharged in a casting machine (2) vertically (V) from a mould, wherein the slab is guided behind the mould in conveying direction (F) by a number of segments (4, 5, 6, 7, 8, 9, 10, 11) wherein each segment (4, 5, 6, 7, 8, 9, 10, 11) comprises a number of segment rollers (12, 13) constructed for contacting the slab surface, and wherein in the region ahead of the casting machine end (14) a number of segment rollers (12, 13) is lifted off the slab surface or not installed in provided mounts so that contact between slab and segment roller (12, 13) is interrupted or not provided,
   characterised in that
   a thermal insulating element (15, 16) is mounted between the slab surface and the at least one segment roller (12, 13) lifted off the slab or not installed.
2. Method according to claim 1, characterised in that the slab in conveying direction (F) behind the mould is guided along a casting curve (3) by a number of casting curve segments (4, 5, 6, 7, 8, 9, 10, 11) and deflected into the horizontal (H), wherein each casting curve segment (4, 5, 6, 7, 8, 9, 10, 11) comprises a plurality of segment rollers (12, 13) constructed for contact with the slab surface and wherein along the casting curve (3) in the region ahead of the casting machine end (14) a number of segment rollers (12, 13) is lifted off the slab surface or not installed in provided mounts.
3. Method according to claim 1 or 2, characterised in that mounting of the insulating element (15, 16) is carried out by horizontal pushing-in from the side of the slab.
4. Method according to claim 1 or 2, characterised in that the thermal insulating elements (15, 16) are fixedly installed between spaced backing rollers or drive rollers, particularly in front of one or in front of both of the slab sides or slab edges.
5. Method according to any one of claims 1 to 4, characterised in that a simulation calculation is performed by means of a computation model, wherein the position of the end of the liquid phase is determined at least on the basis of the casting speed and the slab geometry and wherein the lifting-off of segment rollers (12, 13) is so carried out on the basis of the simulation calculation that lifting-off is carried out for a defined section along the segments (4, 5, 6, 7, 8, 9, 10, 11), in particular along the casting curve (3).
6. Method according to any one of claims 1 to 5, characterised in that the segments (4, 5, 6, 7, 8, 9, 10, 11) are provided with cooling means for cooling the slab, wherein the cooling output is reduced or brought entirely to zero at least at a number of segments (4, 5, 6, 7, 8, 9, 10, 11).
7. Method according to any one of claims 1 to 6, characterised in that the slab is supported by backing rollers (17) at least in the region of the segments (4, 5, 6, 7, 8, 9, 10, 11) with lifted-up segment rollers (12, 13).
8. Method according to any one of claims 1 to 7, characterised in that the lifted-up segment rollers (12, 13) and/or the backing rollers (17) exposed to the radiant heat of the slab are rotationally driven.
9. Method according to any one of claims 1 to 8, characterised in that a furnace (18) is arranged behind the casting machine (1), wherein at least one thermal insulating element (20, 21, 22) for thermal insulation of the slab is arranged in the region between the casting machine end (14) and furnace start (19).
10. Method according to claim 9, characterised in that the at least one thermal insulating element (20, 21, 22) is moved only from time to time into the region of the slab for the thermal insulation thereof.
11. Method according to claim 10, characterised in that the at least one thermal insulating element (20, 21, 22) is moved into the region of a cutter and/or into the region of an in-line stand and/or into the region of a cold-strip removal.
12. Continuous casting plant (1) for continuous casting of a metallic strip, which plant comprises a casting machine (2), in which the metal formed into a slab and with still molten core can be discharged vertically (V) from a mould, wherein a number of segments (4, 5, 6, 7, 8, 9, 10, 11) is arranged in conveying direction (F) behind the mould, and wherein each segment (4, 5, 6, 7, 8, 9, 10, 11) comprises a number of segment rollers (12, 13) constructed for contact with the slab surface, particularly for carrying out the method according to any one of claims 1 to 11,
    characterised in that
    a number of segment rollers (12, 13) with adjusting means is provided in the region ahead of the casting machine end (14) in order to be able to lift the segment rollers (12, 13) off the slab surface, and wherein at least one movable thermal insulating element (15, 16) is present, which in a passive setting can be placed outside the segment (4, 5, 6, 7, 8, 9, 10, 11) and in an active setting can be placed within the segment (4, 5, 6, 7, 8, 9, 10, 11) and between the lifted-off segment roller (12, 13) and the slab.
13. Continuous casting plant (1) according to claim 12, characterised in that a casting curve (3), by which the slab can be deflected into the horizontal (H), with a number of casting curve segments (4, 5, 6, 7, 8, 9, 10, 11) is arranged behind the mould in conveying direction (F), wherein a number of segment rollers (12, 13) with adjusting means is provided along the casting curve (3) in the region ahead of the casting machine end (14) in order to be able to lift the segment roller (12, 13) off the slab surface.
14. Continuous casting plant according to claim 12 or 13, characterised in that the at least one movable thermal insulating element (15, 16) is arranged to be displaceable by the adjusting means horizontally and transversely to the conveying direction (F) of the slab.

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