EP3130414B1 - Melt metallurgy assembly, comprising a mould - Google Patents

Description

The invention relates to a melting metallurgical plant, comprising a mold for discharging a casting strand from a mold outlet opening, wherein the mold is formed as a funnel mold, which has an upper, funnel-shaped area and a lower forming area with two opposite broad side walls and two in each case the two Having broad side walls connecting narrow side walls, wherein the two wide side walls are formed curved at its surface facing the casting strand, so that the cast strand leaves the die outlet opening at an angle to the vertical.

Such a system reveals the DE 37 24 628 C1 , Similar solutions show the DE 694 05 995 T2 and the CH 403 172 A ,

A fusion metallurgical plant with a generic hopper mold is from the DE 39 07 351 C2 known. The mold has an upper region, which is designed as a funnel, and a lower region, which has two parallel side walls running wide. In the area of the broad side walls, the molten material is formed into a strand and conveyed through the mold outlet opening into the subsequent strand guide. Here, in a known manner, the deflection of the cast casting strand from the vertical to the horizontal.

In addition to the generic construction of a mold as funnel mold, other constructions are known, as can be seen for example from EP 0 551 311 B1 , of the EP 0 539 861 B1 , of the EP 0 539 829 B1 and the DE 33 31 575 C2 results.

Other solutions show the DE 38 50 464 T2 , the DE 24 12 053 A1 and the CH 345 121 A ,

• Es existieren im wesentlichen drei unterschiedliche Kokillenarten im Strangguss für Flachprodukte. Die Standardkokille besteht an den Breitseiten aus parallelen senkrechten Kupferplatten (s. Fig. 1 mit der Kokille 1 und der nachfolgenden Strangführung 7). Die Breitseiten der Kokille können in Gießrichtung trapezförmig angestellt werden, um den bei der Erstarrung auftretenden Materialschrumpf auszugleichen. Diese parallelen Breitseiten können leicht gebogen sein (siehe die oben genannte DE 33 31 575 C2 ). Hierdurch ist der Strang schon in der Kokille leicht gebogen (s. Fig. 2 und Fig. 3). Bei einer Kreisbogenanlage hat der Strang beim Verlassen der Kokille bereits die gewünschte Krümmung und es ist keine weitere rissanfällige Biegung in einem Biegebereich nötig. Bei Oval- oder Klothoiden-Anlagen beginnt die Krümmung in der Kokille. Nach dem Verlassen der Kokille wird der Strang zwar weiter gebogen, die auftretenden Kräfte sind aber nicht so hoch und es werden weniger Rollen für die Biegung benötigt. Hierdurch kann die Anlage kürzer und niedriger gebaut werden. Der flüssige Stahl gelangt über ein Tauchrohr vom Tundish in die Kokille. Die Tauchrohre haben in der Regel einen Durchmesser von ca. 50 mm. Hierdurch müssen die Kokillen an der Oberseite ebenfalls eine Öffnung von mindestens 50 mm haben. Zu diesem Zweck ist es vorteilhaft, die eingangs genannte Trichterkokille einzusetzen (s. Fig. 4). Damit können insbesondere Gießstränge mit geringeren Abmessungen produziert werden (sog. CSP-Technologie). Die Tauchrohre können dabei kreisrund sein, was allerdings nicht zwingend ist; beispielsweise sind auch ovale Ausführungen möglich.

To the previously known solutions the following is stated:

• There are essentially three different mold types in continuous casting for flat products. The standard mold consists on the broad sides of parallel vertical copper plates (s. Fig. 1 with the mold 1 and the subsequent strand guide 7). The broad sides of the mold can be made trapezoidal in the casting direction to compensate for the material shrinkage occurring during solidification. These parallel broad sides can be slightly bent (see the above DE 33 31 575 C2 ). As a result, the strand is already slightly bent in the mold (s. Fig. 2 and Fig. 3 ). In a circular arc installation, the strand already has the desired curvature when it leaves the mold and no further crack susceptible bending in a bending area is necessary. In oval or clothoid systems, the curvature begins in the mold. After leaving the mold, the strand is bent further, but the forces are not so high and fewer rollers are needed for the bend. As a result, the system can be built shorter and lower. The liquid steel passes through a dip tube from the tundish into the mold. The dip tubes usually have a diameter of about 50 mm. As a result, the molds at the top must also have an opening of at least 50 mm. For this purpose, it is advantageous to use the aforementioned hopper mold (s. Fig. 4 ). In particular casting strands with smaller dimensions can be produced in this way (so-called CSP technology). The dip tubes can be circular, but this is not mandatory; For example, oval designs are possible.

The hopper mold is wider in the middle in the upper part to insert the dip tube, but tapers in width and after about 400 mm depth in the casting direction. The strand is then conveyed vertically and bent only after the solidification.

To the further known solutions is on the FIGS. 5, 6 and 7 directed. Here are shown different types, all of which realize the principle of the funnel mold and are designed differently. While at FIG. 5 the subdivision into the funnel area and the shaping area is clearly visible, these areas correspond to the solution FIG. 6 into each other over; the same applies to the solution after FIG. 7 , In general, the slabs have a length in the conveying direction, a width transverse to this and a thickness. The mold thickness is essentially the one in FIG. 5a can be seen in the right and left side of the representation.

If a continuous casting plant is to be designed, in particular, with a downstream rolling mill for lower annual volumes, there is a desire to build the plant as compact and small as possible and thus cost-effectively. An essential requirement here is that, despite a short construction, it is ensured that there is no excessively high susceptibility to cracking in the strand, which can result from the strand being bent strongly over relatively short distances.

The invention is therefore based on the object to provide a generic melting metallurgical plant with a mold, with which it is possible to increase the service life of the mold.

The solution of this object by the invention is characterized in that the system further comprises a dip tube, which extends into the funnel-shaped area and supplies the mold with melt, wherein the dip tube is completely curved only in its end facing the mold in the sense of broad side walls.

In this case, the radius of the cast strand is preferably greater on the outer side (ie on the fixed side) than on the inner side (ie on the loose side), the difference preferably corresponding exactly to the strand thickness. Accordingly, then would be the outer radius of curvature equal to the inner radius of curvature plus the strand thickness.

The angle is preferably between 1 ° and 20 °, more preferably between 2 ° and 15 °.

The radius of curvature or the curvature of the two broad side walls is preferably formed in the same direction.

The curvature of the two broad side walls preferably has a radius of curvature which is between 2 m and 2.5 m in the case of a subsequent strand guide designed as a circular arc system. This relates to the two radii of curvature of the two opposite curved surfaces of the mold.

The curvature of the two broad side walls preferably has a radius of curvature which, in the case of a subsequent strand guide designed as an oval or clothoid system, is between 5 m and 20 m, preferably between 8 m and 12 m.

In a clothoid system, the radius of curvature can also be increased upward.

The height of the mold is preferably between 900 mm and 1100 mm.

The mold outlet opening preferably has a width between 40 mm and 70.

According to a special embodiment of the invention, the funnel-shaped region is asymmetrical at least in its upper region, viewed perpendicular to the flow direction of the material passing through the mold.

In the area of the two broad side walls temperature sensors can be integrated. The system can then according to a preferred embodiment of the invention further comprise a control or regulating device which individually as a function of the temperature measured in a wide side wall controls or regulates the passage of cooling liquid through the wide side wall.

According to the invention it is achieved that even with a short design of the system, the bending of the cast strand behind the mold does not exceed excessively large and thus the problem of susceptibility to cracking of the strand is defused. For this purpose, the funnel-shaped mold according to the invention is used, which makes it possible to build the system shorter and thus more cost-effective. Rather, with a curved funnel mold, curvature may already begin during the molding process of the molten material in the mold.

The broad sides of the hopper mold in their shaping area are thus executed bent. This applies to all vertical funnel cork formats listed above.

In a circular arc system, the curved funnel mold already has the circle radius. In oval or clothoid systems, the strand curvature begins in the mold. The funnel canopies are usually 900 to 1,100 mm high. In a sheet system, the curvature extends over the entire mold height. Otherwise, the curvature can run over the entire height or only at the level of the bathroom mirror (about 60 to 100 mm) under the Kokillenoberseite or even lower begin. The strand thickness at Kokillenauslauf is preferably between 40 and 70 mm.

Up to now, vertical funnel cushions have only been used in vertical turn-off systems (CSP systems) or in long USP systems (ultra-strip production) with several segments. In order to be able to produce short low-cost CSP plants with an annual production of 0.5 to a maximum of one million tonnes and a low temperature loss between casting plant and rolling mill, these short sheet plants must be provided with as few pairs of rolls as possible. To avoid bending forces in the mold, at least two pairs of rolls without curvature must first be present in a vertical funnel mold. In the case of the curved funnel mold, however, these rolls can be dispensed with. As a result, the casting is lower and shorter, and thus receives a lower metallurgical length to be optimally designed for low production.

In a vertical mold with subsequent pairs of rolls without bending the casting is too long. In a production with a maximum possible casting speed, the production in the casting plant is then higher than is required in the steel mill or rolling mill.

But even with longer USP systems - built as a circular arc, oval or clothoid system - the curved funnel cane offers the advantage that the strand does not have to be bent so much beyond the mold. Lower bending forces occur so that the risk of cracking is reduced.

Due to the curved dip tube or a dip tube with a flow diversion, the liquid steel does not always strike the same mold position when it is filled into the curved funnel mold. The steel is deflected in the same radius of curvature as the mold was built. As a result, the life of the mold is increased.

The Kokillenoszillation takes place on the entry radius of the strand guide, so even in a clothoid system on the radius, which is present on the first pair of rollers.

Due to the curvature, the funnel cane is not exactly the same length on both broad sides. The arc length on the outside can usually be longer than the arc on the inside, ie in the casting direction. As a result, the solidification can be done faster on the outside and the strand shell there be thicker. To compensate for this, the installation of a temperature measuring sensor makes sense. Through the measured temperatures in the mold and a connected temperature and water quantity calculation program (such as the DSC - Dynamic Solidification Control), the required amounts of mold water for both broad sides can be determined separately to obtain a uniform strand shell thickness

Fig. 1

zeigt schematisch die Seitenansicht einer Kokille in einer ersten Ausführungsform gemäß dem Stand der Technik,

Fig. 2

zeigt schematisch die Seitenansicht einer Kokille in einer zweiten Ausführungsform gemäß dem Stand der Technik,

Fig. 3

zeigt schematisch die Seitenansicht einer Kokille in einer dritten Ausführungsform gemäß dem Stand der Technik,

Fig. 4

zeigt schematisch die Seitenansicht einer Kokille in einer vierten Ausführungsform gemäß dem Stand der Technik,

Fig. 5a

zeigt die Draufsicht auf die Oberseite einer Kokille,

Fig. 5b

zeigt die Draufsicht auf die Unterseite der Kokille und

Fig. 5c

zeigt schematisch die Seitenansicht der Kokille in einer fünften Ausführungsform gemäß dem Stand der Technik,

Fig. 6a

zeigt die Draufsicht auf die Oberseite einer Kokille,

Fig. 6b

zeigt die Draufsicht auf die Unterseite der Kokille und

Fig. 6c

zeigt schematisch die Seitenansicht der Kokille in einer sechsten Ausführungsform gemäß dem Stand der Technik,

Fig. 7

zeigt schematisch die Seitenansicht einer Kokille in einer siebten Ausführungsform gemäß dem Stand der Technik,

Fig. 8

zeigt schematisch die Seitenansicht einer Kokille gemäß der Erfindung,

Fig. 9

zeigt die Draufsicht auf die Oberseite einer erfindungsgemäßen Kokille,

Fig. 10

zeigt schematisch die Seitenansicht des formgebenden Bereichs einer erfindungsgemäßen Kokille nach einer möglichen Ausgestaltung,

Fig. 11

zeigt schematisch die Seitenansicht des formgebenden Bereichs einer erfindungsgemäßen Kokille nach einer anderen möglichen Ausgestaltung,

Fig. 12

zeigt schematisch die Seitenansicht des formgebenden Bereichs einer erfindungsgemäßen Kokille nach einer weiteren möglichen Ausgestaltung,

Fig. 13

zeigt die Draufsicht auf die Oberseite einer erfindungsgemäßen Kokille,

Fig. 14

zeigt schematisch die Seitenansicht einer erfindungsgemäßen Kokille,

Fig. 15

zeigt schematisch die Seitenansicht einer erfindungsgemäßen Kokille mit Tauchrohr zur Versorgung mit Schmelze,

Fig. 16

zeigt schematisch das Tauchrohr gemäß einer erfindungsgemäßen Ausgestaltung und

Fig. 17

zeigt schematisch das Tauchrohr gemäß einer nicht erfindungsgemäßen Ausgestaltung, links in perspektivischer Darstellung und rechts im Schnitt.

In the drawings, embodiments of the invention are shown.

Fig. 1

shows schematically the side view of a mold in a first embodiment according to the prior art,

Fig. 2

shows schematically the side view of a mold in a second embodiment according to the prior art,

Fig. 3

shows schematically the side view of a mold in a third embodiment according to the prior art,

Fig. 4

shows schematically the side view of a mold in a fourth embodiment according to the prior art,

Fig. 5a

shows the top view of the top of a mold,

Fig. 5b

shows the top view of the bottom of the mold and

Fig. 5c

shows schematically the side view of the mold in a fifth embodiment according to the prior art,

Fig. 6a

shows the top view of the top of a mold,

Fig. 6b

shows the top view of the bottom of the mold and

Fig. 6c

shows schematically the side view of the mold in a sixth embodiment according to the prior art,

Fig. 7

1 schematically shows the side view of a mold in a seventh embodiment according to the prior art,

Fig. 8

shows schematically the side view of a mold according to the invention,

Fig. 9

shows the top view of the top of a mold according to the invention,

Fig. 10

shows schematically the side view of the forming region of a mold according to the invention according to a possible embodiment,

Fig. 11

schematically shows the side view of the forming region of a mold according to the invention according to another possible embodiment,

Fig. 12

shows schematically the side view of the forming region of a mold according to the invention according to another possible embodiment,

Fig. 13

shows the top view of the top of a mold according to the invention,

Fig. 14

shows schematically the side view of a mold according to the invention,

Fig. 15

shows schematically the side view of a mold according to the invention with dip tube for supply with melt,

Fig. 16

schematically shows the dip tube according to an embodiment of the invention and

Fig. 17

schematically shows the dip tube according to a non-inventive embodiment, left in perspective and right in section.

As explained above, concern the FIGS. 1 to 7 previously known solutions.

In FIG. 8 a mold according to the invention is shown.

The mold 1 has a mold outlet opening 2, through which emerges the molded and prestabilized strand. Over its height h, the mold 1 has an upper funnel-shaped region 3 and a lower shaping region 4. The shaping area 4 is formed by the two broad side walls 5 and 6, which form the melt to the strand of the desired shape. The flow direction of the material is indicated by F.

The preformed strand passes below the mold outlet opening 2 directly into the strand guide 7, of which only a few rollers are shown schematically.

It is essential that the two broad side walls 5 and 6 are formed curved at its surface facing the casting strand. In FIG. 8 the radius of curvature is indicated by r _K. Accordingly, the cast strand leaves the mold outlet opening 2 at an angle α to the vertical V. This angle is for example in a range between 2 ° and 15 °.

The radii of curvature are usually between 2 m and 2.5 m in a bow machine and between 5 m and 20 m in an oval or clothoid system, preferably here at 10 m.

Indicated in FIG. 8 nor that temperature sensors 10 and 11 can be accommodated in the respective broad side walls 5 and 6. By means of a control or regulating device, not shown, so that the two wide side walls can be controlled individually in their temperature, so that there is a symmetrical Gießstrang despite curvature in the forming region 4 of the mold 1 as a result.

In FIG. 9 is the top view of the upper edge of the mold to see where a sectional plane is indicated by dashed lines. These are in the FIGS. 10, 11 and 12 various forms of the curvatures of the broad side walls indicated.

In FIG. 10 There is a curvature that goes beyond the vertical.

According to FIG. 11 The curvature extends to the vertical.

The solution according to FIG. 12 shows that the curvature can only begin after a parallel section of the broad side walls.

As in FIG. 13 can be seen, the funnel can also be carried out only on one broad side, preferably on the outer radius of the mold.

FIG. 14 shows the mold with curvature on both broad sides, but only half-sided funnel.

In FIG. 15 It can be seen how the dip tube 8 dips into the region of the funnel of the mold 1 in order to supply it with melt. Arrangements are made here to facilitate insertion of the dip tube into the funnel area. This is on the other FIGS. 16 and 17 Referenced.

The liquid steel flows from the tundish through the dip tube 8 in the mold 1. In a vertically inserted, straight and not bent at the end dip tube of the steel always meets in a curved mold according to the invention in the same place. At this position, the mold would wear much faster. The copper wall is ground more strongly there and the service life of the mold is thus shortened.

If, however, the dip tube 8 is also bent slightly in accordance with the Kokillenkrümmung, the hot steel does not always apply directly to the same position of the mold wall. As a result, the Kokillenstandzeit is significantly extended. It is also possible that the dip tube 8 is not completely curved, but only has an arcuate extension at the rear part seen in the casting direction in order to divert the steel flow somewhat in the casting direction.

In this case, if the flow deflection is not wider and longer than the vertical part of the dip tube, the risk that dip tube 8 and mold 1 touch each other, for example in the Kokillenoszillation.

In the FIGS. 16 and 17 It can be seen how the dip tube 8 has said curvature in its end region 9. This applies accordingly FIG. 16 the entire end area 9 (fully curved dip tube) or according to FIG. 17 (Not according to the invention) only a part of the side wall (dip tube with flow deflection).

In this case, a device should be provided which prevents the dip tube 8 can not be accidentally planted around the wrong tundish. Any position rotated by more than 5 ° must be structurally excluded.

Thus, for example, some (advantageously three or four) different width bolts may be attached to the upper end of the dip tube. At the tundish outlet appropriate grooves are provided. So the dip tube is always mounted in the correct position on the tundish.

LIST OF REFERENCE NUMBERS

1

mold

2

Mold outlet opening

3

upper funnel-shaped area

4

lower forming area

5

Wide side wall

6

Wide side wall

7

strand guide

8th

dip tube

9

End of the dip tube

10

temperature sensor

11

temperature sensor

r _K

radius of curvature

α

angle

V

vertical

F

flow direction

H

Height of the mold

Claims (10)

1. Melt metallurgical plant comprising a mould (1) for the issue of a cast strip from a mould outlet opening (2), wherein the mould (1) is constructed as a funnel mould having an upper funnel-shaped region (3) and a lower shape-imparting region (4) with two mutually opposite wide side walls (5, 6) and two narrow side walls respectively connecting the two wide side walls, wherein the two wide side walls (5, 6) are formed to be curved (r_K) at the surface thereof facing the cast strip so that the cast strip leaves the mould outlet (2) at an angle (α) to the vertical (V),
   characterised in that
   the plant further comprises an immersion pipe (8) which reaches into the funnel-shaped region (3) and supplies the mould (1) with melt, wherein the immersion pipe (8) is fully curved in the sense of the wide side walls (5, 6) only in the end region (9) thereof facing the mould (1).
2. Plant according to claim 1, characterised in that the angle (α) lies between 1° and 20°.
3. Plant according to claim 1 or 2, characterised in that the radius (r_K) of curvature or the curvature of the two wide side walls (5, 6) is in the same sense.
4. Plant according to claim 3, characterised in that the curvature of the two wide side walls (5, 6) has a radius (r_K) of curvature which in the case of a downstream strip guide (7) formed as a circularly arcuate installation lies between 2 metres and 2.5 metres.
5. Plant according to claim 3, characterised in that the curvature of the two wide side walls (5, 6) has a radius (r_K) of curvature which in the case of a downstream strip guide (7) formed as an oval or clothoid installation lies between 5 metres and 20 metres.
6. Plant according to any one of claims 1 to 5, characterised in that the height (h) of the mould (1) is between 900 millimetres and 1,100 millimetres.
7. Plant according to any one of claims 1 to 6, characterised in that the mould outlet opening (2) has a width between 40 millimetres and 70 millimetres.
8. Plant according to any one of claims 1 to 7, characterised in that the funnel-shaped region (3) as seen perpendicularly to the flow direction (F) of the material passing the mould (1) is formed to be asymmetrical at least in its upper region.
9. Plant according to any one of claims 1 to 8, characterised in that temperature sensors (10, 11) are integrated in the region of the two wide side walls (5, 6).
10. Plant according to claim 9, characterised in that it further comprises a controlling or regulating device which controls the conducting of cooling liquid through a wide side wall (5, 6) individually in dependence on the temperature measured in the wide side wall (5, 6).

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