EP0920938A1 - Method and continuous casting facility for producing thin slabs - Google Patents

Abstract

The first section (0) is designed for thickness reductions of 10-40 mm. The segment (1) has at least 3 bending points producing a radius of curvature of 3-6 m. The straightening roll section has at least 3 reversed bending points, with the last of these points (at a casting speed forming 80 % of the maximum) located at least 2 m away from the point of complete solidification of the slab. Slab thickeness reduction takes place by a vertical section (0) of casting rolls located directly below the mold (K). The slab is bent by a section (1) over a several bending points. Before complete solidification, the slab is straightened over several reversed bending points. The segment (0) is designed for thickness reductions of 10-40 mm. The segment (1) has at least 3 bending points producing a radius of curvature of 3-6 m. The straightening roll segment has at least 3 reversed bending points, with the last of these points (at a casting speed forming 80 % of the maximum) located at least 2 m away from the point of complete solidification of the slab.

Description

The invention relates to a method and an apparatus for Production of slabs on a preferably vertical mold having continuous casting plant preferably for thin slab plants for casting preferably steel with a solidification thickness, for example from 60 to 120 mm e.g. 80 mm and casting speeds up to 10 m / min and a maximum casting performance of approx. 3 million / t / a.

The well-known thin slab plants with a strand thickness reduction, realized with a casting and rolling device, reduce the strand thickness immediately below the continuous casting mold, with one or two Castor pairs is equipped, mainly in the so-called "segment 0 ". Here the thickness of the strand is increased e.g. from 65 mm to 40 mm a metallurgical length of approx. 2 m, i.e. over the entire length of the segment (or scaffolding) 0, which is not arranged vertically, reduced at a maximum casting speed of 6 m / min. This Plant data lead to a strand thickness reduction of up to 38% and a maximum deformation speed in the strand thickness 1.25 mm / s.

During this dwell time of the strand with liquid core, the Strand shell with a thickness of approx. 8 to 12 mm when it enters into segment 0, due to its bulging between the continuous casting machine rolls, badly deformed. This inner deformation takes off with increasing casting speed and system height or also ferrostatic Pressure increases and increases with decreasing roll spacing from. It should be noted that a roll diameter of e.g. 120 up to 140 mm from mechanical engineering criteria (mechanical load, design-related limits, especially for intermediate storage Roles) so far not to be undercut. A possible mechanical engineering Solution could be a sliding plate, also known as a "grid", represent, however, for the implementation of a reduction of Strand thickness is unsuitable.

• der Ausbuchtung bzw. -bauchung des Stranges zwischen den Rollen
• dem Biegen des Stranges aus der Senkrechten in den inneren Kreisbogen
• dem Richten des Stranges in die Horizontale
• der Abweichung der Rollen aus der idealen Strangführungslinie durch
  • Rollensatz
  • Rollenschlag und der
• Zugspannung

bestimmt.In normal continuous casting, the internal deformation is essentially of

• the bulge or bulge of the strand between the rolls
• the bending of the strand from the vertical into the inner circular arc
• straightening the strand horizontally
• the deviation of the rollers from the ideal strand guide line
  • Roller set
  • Roll hit and the
• Tension

certainly.

In addition to these inner and surface deformations the deformations are to be expected due to the reduction in strand thickness or the so-called casting rolling in segment 0 be generated. This specific internal deformation overlaps the Deformation already generated in segment 0, essentially caused through the strand bulge and the bending process from the Vertical in the inner arc. This accumulation of the individual specific deformations can lead to an overall deformation lead, which becomes critical and to the tearing of the inner as well outer strand shell leads.

This type of additional strand shell loading by the casting rolling or the reduction in thickness during solidification in the e.g. 2nd m long segment 0 immediately below the mold is in the Patent specifications DE 44 03 048 and DE 44 03 049 described, and in the diagram of Figure 1 shown in detail by way of example.

According to FIG. 1, a 1 m long vertical mold is included one or two pairs of casters to a 2 m long segment 0, in which the strand both over several steps in the inner circular arc bent as well as reduced in thickness. These two simultaneous processes or deformations lead to a overlapping cumulative total deformation consisting of the Bending deformation (D-B) and the casting roll deformation (D-Gw). The Total deformation (D-Ge) that acts on the strand shell can become larger than the critical limit deformation (D-Kr) and too Cracking the inner as well as the outer strand shell. This Danger increases with increasing casting speed due to a roller spacing or roller diameter in segment 0, the mechanical limits can not be arbitrarily small.

In addition, when describing this problem, consider that the limit deformation (D-Kr) is specific to each steel grade behaves. For example, a thermoforming quality with regard to absorption less deformation without the consequences of cracking critical as e.g. a micro-alloyed API X 80 steel grade.

Furthermore, the training and expansion of the overheated takes place Melt or the pure melting phase in the strand, displayed through the straight line (G1) depending on the casting speed, a significant influence on the inner strand quality. On indicated Example in Figure 1, the pure melting phase is sufficient the geometrically lowest liquidus temperature in the middle of the strand at a casting speed VG of 5 m / min to approx. 1.5 m and at VG10 m / min up to approx. 3.0 m below the pouring level. Below At this point, the 2-phase area lies over the entire strand thickness before, consisting of melt and crystal, which with increasing distance towards the top of the sump or the final solidification Loss of melting in favor of crystal loses.

With a crystal content of 50%, i.e. half the distance between the lowest liquidus point of 1.5 m at e.g. VG 5 m / min and the final solidification, which takes place at approx. 15 m, i.e. at 8.25 m (1.5m + (15m - 1.5m) x0.5 = 8.25m) (Gw-50%) has the melt / crystal phase a viscosity of 10,000 cP. With a crystal part of 80%, the 2-phase area takes a viscosity of 40,000 cP on, whereas the pure melting phase down to the lowest liquidus point has a viscosity of only approx. 1 to 5 cP depending on the steel grade and also its partial viscosity between the crystals (Crystal network or dendrites) practical until final solidification does not increase, therefore keeps constant.

In order to establish a relationship between the viscosities mentioned in the 2-phase area and known everyday substances, the following substances are recalled: - Water at 20 ° C 1 cp = 10exp3 Ns / m exp2 - olive oil at 20 ° C 80 cp - honey at 20 ° C 10,000 cp - Nivea at 20 ° C 40,000 cp - margarine at 20 ° C 100,000 cp - bitumen at 20 ° C 1,000,000 cp

These viscosities make it clear that for good forced convection and with it a good crushing of crystals a strand thickness reduction in the core of the strand a crystal / melt structure should be available, i.e. at maximum casting speed the strand should already be in the area of segment 0 essentially have a 2-phase area or the pure melt phase or also the overheating area or the penetration zone for the Rise of oxides no longer exist. These conditions in connection with the oxidic degree of purity have to the knowledge led that the segment 0 should once be vertical and to the second should only serve to reduce the strand thickness and not yet in addition to bending the strand.

In Figure 1, these poor conditions described above represents, the overheating zone or the deepest liquidus point up to the end of segment 0 and thus already in the inner circular arc of the continuous caster in the case of maximum Casting speed from 10 m / min, indicated by the dot (1.1) on the straight line (G1). These casting conditions are for both the strand shell deformation as well as for the oxidic degree of purity extremely disadvantageous.

The 2-phase area - spanned between two straight lines, namely the Straight line (G1) for the arrangement of the lowest liquidus point in Dependence on the casting speed and the straight line (G2) for the deepest solidus point or the final solidification depending from the casting speed - starts in the case of the maximum casting speed of 10 m / min at the end of segment 0, which is the strand thickness reduction makes.

FIG. 3, partial image 3a (see the left half of FIG. 3) the training of the different phases is also exemplary of a 100 mm thick strand from the mold level in the mold subsequent strand thickness reduction in the 2 m long segment 0 from 100 mm to 80 mm solidification thickness up to final solidification in last segment No. 14 for the maximum casting speed of 10 m / min. The drawing 3a makes it very clear that the Segment 0 both caused the highest possible deformation through the reduction in strand thickness and the bending process from the vertical in the inner arc over five bending points, in the Strand brings bad conditions for the upgrade as well of oxides in the mold level and thus in the pouring slag.

In addition, drawing 3a makes it clear that at a casting speed of 5 m / min the reduction speed on the shell of the strand acting from 100 mm to 80 mm thickness, i.e. by 20% is reduced, 0.833 mm / s and at a casting speed of 10 m / min is 1.66 mm / s. This rate of reduction of Strand thickness is a direct measure of the deformation of the strand shell represents that at the entry into segment 0 at a casting speed of 5 m / min approx. 10.3 mm and at a casting speed of 10 m / min is about 7.3 mm thick. This strand deformation caused by the casting rolling, is high and is also by the Speed increase from 5 to 10 m / min not only from 0.83 to 1.66 mm / s doubled, as is the simplified calculation size 1.66 mm / s expresses, but the increase in speed goes with a quadratic function in the deformation.

These high deformations, moreover superimposed by the bending processes in segment 0, lead to the risk of tears of the inner as well as the outer strand shell and here especially for those sensitive to cracks Steel grades.

Sending the above-mentioned knowledge and relationships, the invention is based, for high-speed slab plants the task on the basis of devices for strand thickness reduction a process and a immediately below the mold To propose a system concept for a continuous caster, one ensures optimal surface and interior quality of the steel strand.

• einen minimalen ferrostatischen Druck oder auch eine minimale Anlagenhöhe zwischen dem Gießspiegel in einer vorteilhaft hydraulisch angetriebenen, oszillierenden Senkrecht-Kokille und der Enderstarrung im horizontal verlaufenden Bereich der Strangführung,
• minimierte Deformationsdichte-Verteilung der Gesamtdeformation, bestehend aus der Gießwalzdeformation und der Biegedeformation bei einer Senkrecht-Abbiegeanlage mit konkav ausgeführten Kokillenbreitseiten, vorgegebenen Rollendurchmessern in der Strangführung und bis zu einer maximalen Gießgeschwindigkeit von vorteilhaft 10 m/min,
• einem völligen Abbau der Überhitzungsphase oder Penetrationszone für das Aufsteigen von Oxiden im Senkrechtteil der Stranggießanlage d.h. im Segment 0, dem Maschinenelement zur Durchführung der Strangdickenreduktion bei maximaler Gießgeschwindigkeit von z.B. 10 m/min, zur Sicherstellung einer Strangsymmetrie im Bereich der Überhitzung oder reinen Schmelzphase,
• einen Gießwalzvorgang bei maximaler Gießgeschwindigkeit von z.B. 10 m/min im Segment 0, bei dem das 2-Phasengebiet Schmelze/Kristall in der Mitte des Stranges spätestens am Ende des Segmentes 0, das die Strangdickenreduktion oder das Gießwalzen vornimmt, vorliegt,
• eine Deformationsgeschwindigkeit der Strangschale im Segment 0 von maximal 1,2 mm/s,
• eine minimierte Biegedeformationsdichte im Segment 1 aus der Senkrechten über mehrere Biegepunkte in den inneren Kreisbogen unabhängig von der Gießwalzdeformation im Segment 0, das direkt vor dem Segment 1 angeordnet ist,
• eine minimierte Richtdeformationsdichte aus dem inneren Anlagenradius über mehrere Richt- oder Rückbiegepunkte in die Horizontale, vorzugsweise mindestens 12 s oder mindestens 2 m vor der Enderstarrung bezogen auf eine Durchschnitts-Gießgeschwindigkeit von 80% der maximalen Gießgeschwindigkeit.

This object is achieved with the features specified in method claim 1 and in the device claim 7. The measures of the subclaims contain expedient and advantageous embodiments of the invention. This represents an unexpected solution to the numerous and complex problems shown and is described in more detail below. The invention secures and combines the features now listed, such as:

• a minimal ferrostatic pressure or a minimal plant height between the casting level in an advantageously hydraulically driven, oscillating vertical mold and the final solidification in the horizontal region of the strand guide,
• minimized deformation density distribution of the total deformation, consisting of the casting roll deformation and the bending deformation in a vertical bending system with concave wide sides, predetermined roll diameters in the strand guide and up to a maximum casting speed of advantageously 10 m / min,
• a complete reduction of the overheating phase or penetration zone for the rise of oxides in the vertical part of the continuous casting installation, ie in segment 0, the machine element for reducing the strand thickness at a maximum casting speed of, for example, 10 m / min, to ensure strand symmetry in the area of overheating or pure melting phase,
• a casting and rolling process at a maximum casting speed of, for example, 10 m / min in segment 0, in which the 2-phase melt / crystal region in the middle of the strand is at the end of segment 0 at the latest, which carries out the strand thickness reduction or the casting rolling,
• a deformation speed of the strand shell in segment 0 of a maximum of 1.2 mm / s,
• a minimized bending deformation density in segment 1 from the vertical over several bending points in the inner circular arc independently of the casting roll deformation in segment 0, which is arranged directly in front of segment 1,
• a minimized directional deformation density from the inner system radius over several straightening or back bending points into the horizontal, preferably at least 12 s or at least 2 m before final solidification, based on an average casting speed of 80% of the maximum casting speed.

In FIGS. 2 and 3b (see the right half of Figure 3) is the invention with regard to the method and the Characterized device.

FIG. 2 shows the distribution of the inner strand deformation according to the invention over the strand guide length with the identification of the System configuration for the casting speeds 5 and 10 m / min as well as the expansion of the pure melting phase, the final solidification in Dependence on the casting speed and the limit deformation represents.

The continuous casting process is constructed according to the invention so that the Strand deformation density via the strand guide is minimized and each type of deformation independently of the other one after the other arranged takes place. The deformation curves (D-5) and (D-10) run below the critical and thus limit deformation (D-Kr). Furthermore, the deformation curves make it clear that a Cumulation of deformations caused by casting rolling and the bend is avoided in that in the embodiment the strand thickness reduction (D-Gw) in a 3 m long, vertical Segment 0 and the bend (D-B) of the strand in the subsequent Segment 1 over e.g. five bending points is made.

It can also be seen from FIG. 2 that the lowest liquidus point (1.1) or the overheating zone or the penetration zone in the Inside the strand, which is about 10% of the solidification time at one Overheating of 25 ° C of the steel in the manifold maximum casting speed of 10 m / min to 3 m below the Casting level extends or extends up to 2 m deep into segment 0. This ensures that oxides are free and symmetrical to Strand solidification in the vertically arranged pure melting phase can rise and at the same time below the lowest liquidus point, from which the 2-phase area up to the inside of the strand completely filling the middle of the strand, crushing the crystals and the suppression of macro and mid-intensification by the Cast rolling process over the remaining length of 1 m in segment 0 can take place.

The 2-phase area is from the straight line (G1), which is the lowest position of the liquidus point and the straight line (G2) which determine the position of the Represents sump tip as a function of the casting speed, spanned. The 2-phase area crystal / melt begins in the case from VG 5 m / min at approx. 1.5 m (liquidus point 1.2) below the pouring level or 0.5 m after the strand enters segment 0 and ends at about 15.1 m (point 2.2 (in Fig. 2)) with the swamp tip; in the case of a casting speed of 10 m / min, the 2-phase area begins at about 3 m (1.1) and ends with the swamp tip at approx. 30.2 m (2.1) (see Fig. 2).

The strand reduction or the casting and rolling process with a full 2-phase area in the case of VG 5 there is an extension between the strand shells m / min casting speed over 2.5 m and in the case of VG 10 m / min over 1 m of the remaining length of segment 0. In both cases a Forced convection of the 2-phase area and thus an improvement the inner strand quality guaranteed.

The bending back of the strand from the inner radius - e.g. 4 m above several bending points, for example five reference points - into the 3 is exemplarily in the 2 m long segment 4 to ensure a gentle re-deformation (D-R) and at the same time the final solidification and thus the strand quality not negatively influenced by strand deformation.

Furthermore, reference should be made to the partial image 3b shown in FIG. 3. Here, especially in comparison to drawing 3a, it becomes clear that the casting roll deformation (D-Gw) from 100 to 80 mm over a 3 m long segment 0 and therefore only with a rate of deformation of 1.11 mm / s in the case of a casting speed of 10 m / min and 0.55 mm / s in the case of VG 5 m / min. This rate of deformation is significantly reduced from that of 1.66 mm / s in the case of a 2 m long segment 0 and 10 m / min casting speed. The rate of deformation is thus below the as the critically known value of 1.25 mm / s.

• eine genaue Oszillation und die Variation der Hubhöhe, der Frequenz sowie der Oszillationsform während des Gießens,
• eine gleichförmige Schlackenschmierung über die gesamte Strangbreite,
• eine ruhige Badspiegelbewegung,
• einen gleichförmigen Wärmedurchgang in die Kokille,
• einen zentrischen Strangverlauf sowohl in der Kokille als auch in der Strangführung und
• eine hohe Gießsicherheit unter Vermeidung von Durchbrüchen

sicherzustellen. The advantages achieved by the invention result from ensuring a continuous casting process for thin slabs with a solidification thickness between preferably 60-120 mm with a casting and rolling stage directly below the vertical mold in a vertically arranged segment 0. The vertical mold, into which, according to FIG 4 an immersion spout (Ta) guides the steel out of the distributor (V), should advantageously have concave broad side plates and be hydraulically driven in order to

• an exact oscillation and the variation of the lifting height, the frequency and the form of oscillation during casting,
• uniform slag lubrication across the entire strand width,
• a calm bath mirror movement,
• uniform heat transfer into the mold,
• a central strand course both in the mold and in the strand guide and
• a high level of casting reliability while avoiding breakthroughs

ensure.

The strand guide can also be concave with a deviation from the Linearity of maximum 2 x 12 mm to be formed around the strand straight and safe even at high casting speeds To lead strand. This can e.g. with a concave design Profile of the strand guide rollers can be realized. In addition, must the extent of the concave deflection from the mold outlet or from the first strand guide role to the last role of the strand guide not constant and functional towards the end of the strand guide steadily except for a minimal residual concavity or residual crowning remove the slab from 0 mm.

The segment 0 should be arranged vertically and exclusively be used for the strand thickness reduction. It should be one Have a minimum length of one at maximum casting speed Speed in the reduction of the casting thickness of less than 1.25 mm / s generated in the strand and at the same time at the maximum possible Pouring speed has a minimum length that the complete Reduction of overheating and, if possible, a smashing the crystal phase in the 2-phase area crystal / melt and suppression which ensures macro and mid-increase. In this Example described segment 0 has a length of 3 m.

In segment 1, i.e. immediately after the casting process in Segment 0, according to the invention, the bending of the strand with a 2-phase mixture between the strand shells over, for example, five Bending points in the inner arcs of e.g. 4 m in segment 1 made to keep the strand shell deformation density low and do not cumulate with the previous roll forming deformation allow.

According to the geometric relationships and a plant height from e.g. About 8 m there is a back bend in the horizontal for example via five reference points in segment 4 after approx. 12 m Distance from the mold level, which takes place well before final solidification, the at about 15 or 30 m distance from the casting level in the case of VG 5 or 10 m / min is completed. Between the back bend and the associated deformation of the inner strand shell and the Final solidification, which is extremely sensitive to deformation, are thus 36 s or 108 s, with a disturbance of the final solidification in the area of the swamp tip and the associated errors in the core the slab are excluded by the back bending process.

• einer 1,2 m langen Senkrecht-Kokille mit einer Dicke von maximal 180 mm in der Mitte des Gießspiegels und einer minimalen Dicke von 100 mm in der Mitte und einer Dicke von 100 mm im Schmalseitenbereich des Kokillenaustritts,
• einem vertikalen Segment 0, ausgerüstet als 3 m langes Zangensegment zur Reduktion der Strangdicke auf 80 mm,
• einem Segment 1 mit fünf Biegepunkten und einem inneren Radius von 4m,
• den Segmenten 2 und 3 im inneren Kreisbogen,
• einem Segment 4 mit fünf Richtpunkten und
• den Segmenten 5 bis 13 im horizontalen Teil der Strangführung.

FIG. 4 shows, as an exemplary embodiment of the invention, a single-core continuous casting installation for producing a maximum of 3.0 million tpa on average for a strand thickness of 100 mm at the outlet of the vertical mold with hydraulic drive, a solidification thickness of 80 mm and a maximum casting speed of 10 m / min, consisting of

• a 1.2 m long vertical mold with a maximum thickness of 180 mm in the middle of the mold level and a minimum thickness of 100 mm in the middle and a thickness of 100 mm in the narrow side area of the mold outlet,
• a vertical segment 0, equipped as a 3 m long pliers segment to reduce the strand thickness to 80 mm,
• a segment 1 with five bending points and an inner radius of 4m,
• segments 2 and 3 in the inner arc,
• a segment 4 with five reference points and
• segments 5 to 13 in the horizontal part of the strand guide.

The entire continuous caster has a metallurgical length of approx. 30 m, of which approx. 4 m are arranged vertically (K and 0), approx. 8 m in a circular arc (segment 1,2,3,4) and approx. 18 m horizontally (Segments 5 to 13). At a casting speed of maximum 10 m / min the lowest liquidus point ((1.1)) protrudes about 2 m into the 3 m long segment 0 into it, with an optimal ascent of oxides into the pouring slag and at the same time a symmetrical distribution of the oxides remaining in the steel but also a smashing of the Crystals in the 2-phase region and suppression of nuclear segregation is guaranteed in the strand. At approx. 16.5 m distance from the mold level there is a 2-phase mixture with 50% crystal content ((Gw-50%)) with a viscosity of 10,000 cP (same as honey at 20 ° C). In addition, the final solidification ((2.1)) takes place in the last segment (13) far from the back bend in segment 4. Between the back bend and the final solidification in the swamp tip area is undisturbed Solidification time of approx. 108 s, which is a good core solidification ensures.

Reference list

- (D-5)

Inner strand deformation during solidification for 5 m / min casting speed

- (D-10)

Inner strand deformation during solidification for 10 m / min casting speed

- (D-B)

Bending deformation on the inner strand shell at the Bend of the strand from the vertical to the inner arc

- (D-R)

Back-bending deformation on the inner strand shell when straightening the strand from the inner circular arc across several reference points in the horizontal

- (D-Gw)

Casting roll deformation on the inner strand shell

- (D-Ge)

Total deformation on the inner strand shell (D-Ge) = (D-B) + (D-Gw).

- (D-Kr)

Critical or limit deformation of the inner strand shell

-(1)

lowest point of overheating or lowest liquidus point as a distance in m from the casting level depending from the casting speed

- (1.1)

Distance of the lowest liquidus point from the casting level for 10 m / min casting speed

- (1.2)

Distance of the lowest liquidus point from the casting level for 5 m / min casting speed

- (Gw-50%)

2-phase mixture with 50% crystal and approx. 10 000 cP (equivalent to honey at 20 ° C) at a distance of 8.25 m and 16.6 m from the casting level in the case of Casting speeds 5 and 10 m / min

- (2)

lowest solidus point or swamp tip in m from Casting level depending on the casting speed

- (2.1)

Distance of the swamp tip from the casting level for one Casting speed of 10 m / min

- (2.2)

Distance of the swamp tip from the casting level for one Casting speed of 5 m / min

- V

Distributor

- Ta

Diving spout

- K

Vertical mold with hydraulic drive for oscillation

- 0

Segment 0 as a pliers segment

- 1

Segment 1 as a bending segment

- 2nd

Segment 2 as an arc segment

- 3rd

Segment 3 as an arc segment

- 4th

Segment 4 as a rebend segment

- 5th

Segment 5 as a horizontal segment

- 6th

Segment 6 as a horizontal segment, ....

- 14

Segment 14 as a horizontal segment

Claims (16)

Method for producing thin slabs on a continuous caster, in particular a vertical mold,
characterized by
that only the strand reduction, also called casting rolls, is carried out with a first segment (0) of the strand guide running directly below the mold, the segment (1) arranged immediately below the first segment (0) bends the strand over several bending points in the inner circular arc and before the final solidification, the strand is bent back horizontally over several backbend points. Method according to claim 1,
characterized by
that a vertical mold with a concave profile of its broad sides, which runs symmetrically in the horizontal, is used. Process according to claims 1 and 2,
characterized by
that the concave profile is completely withdrawn from the beginning of the mold (casting area) to the end of the mold over a functional course. Process according to claims 1 and 2,
characterized by
that the concave profile from the beginning of the mold (casting area) to the end of the mold is reduced to a residual concavity of a maximum of 10% of the solidification thickness per broad side plate. Method according to claim 4,
characterized by
that the residual concavity in the strand guide is functionally reduced to a concavity or crowning of the slab of at least +0 mm. Method according to one of claims 1 to 5,
characterized by
that the length of the vertically running segment (0) is dimensioned such that at maximum casting speed the pure melting phase or the deepest liquidus point is preferably below the first third and the end of the segment (0), but not shifted from the segment (0) and with the rate of deformation in the strand when the strand thickness is reduced, a value of 1.25 mm / s is not exceeded. Continuous casting installation for carrying out the method according to one of claims 1 to 6,
characterized by
that the vertical segment (0) is designed for a strand thickness reduction between 40 and 10 mm, the following segment (1) has at least three bending points and the radius of the inner circular arc is between 6 and 3 m and at least three orientation points are formed for the backward bending of the strand from the inner circular arc into the horizontal and the last backward bending point is at least 2 m from the bottom of the sump at 80% of the maximum casting speed. Continuous caster according to claim 7,
characterized by
that the vertical segment (0) has at least a length of 2 m. Continuous caster according to claim 7 or 8,
characterized by
that the system height between the casting level and the lower edge of the strand in the horizontal strand guide is not more than 10 m. Continuous caster according to one of claims 7 to 9,
characterized by
that the mold has a thickness between 160 and 70 mm in the narrow side area. Continuous caster according to one of claims 7 to 10,
characterized by
that the broad sides of the vertical mold have a horizontally running, concave and symmetrical profile with an opening in the middle of the broad side of the area of the mold level of maximum 40 mm per broad side. Continuous caster according to one of claims 7 to 11,
characterized by
that the concave profile of a maximum of 40 mm on each broad side in the mold level area of the mold is designed to decrease completely by the end of the mold. Continuous caster according to one of claims 7 to 11,
characterized by
that the concave profile of a maximum of 40 mm per broad side in the mold level of the mold is functionally designed to go back to a residual concavity of maximum 12 mm per broad side up to the end of the mold. Continuous caster according to one of claims 7 to 11 and 13,
characterized by
that the residual concavity at the mold exit in the strand guide is functionally designed to decrease the concavity or crowning of the slab from a minimum of +0 mm. Continuous caster according to one of claims 7 to 14,
characterized by
that the continuous caster length or the strand guide is at least 10 m. Continuous caster according to one of claims 7 to 15,
marked by
a continuous casting speed of maximum 10 m / min.

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