EP1567297B1 - Impact pad for protecting the impact zone of a incoming molten metal stream in a metallurgical vessel - Google Patents

Abstract

A vessel acts as an intermediate storage point for molten steel prior to its discharge into a casting mold. The vessel is protected from the impact of incoming molten metal by a tundish (4) which has a cover (4d) which is partially destroyed by the incoming molten metal (3). The tundish is made of a incombustible material. The thin-walled cover is made of the same type of metal as the incoming molten steel and is perforated or incorporates fenestrations. The dish diameter is only slightly larger than the flow of incoming molten metal.

Description

• Ein gattungsgemäßer Einlegekörper ist aus der DE 2643009 bekannt. Dieser Einlegekörper weist zum Schutz der Aufprallfläche eines Zwischenbehälters vor einem auftreffenden Gießstahl einen Aufprallbereich auf, der durch ein Rost gebildet ist. Die das Rost bildenden Begrenzungen verhindern jedoch nur ungenügend ein Verspritzen des auftreffenden Gießstahls.

The present invention relates to an insert body for protecting the impact surface of a cast steel in a metallurgical vessel, in particular an intermediate container for continuous casting, with the boundary areas surrounding the impact area, which form a trough together with the impact area:

• A generic insert body is known from DE 2643009. This insert body has to protect the impact surface of an intermediate container in front of an impinging cast steel impact area, which is formed by a grid. However, the limitations forming the grate prevent inadequate splashing of the impinging cast steel.

From CH 581 513 A is an insert body made of metal to protect the impact surface of a pouring stream in a metallurgical Known vessel. The insert body has a wire grid, which extends over the upper opening of the insert body and has the task of braking the falling beam during passage.

From FR 66 139 E, an insert body is known, can be arranged in the material that is to mix with the incident pouring stream. So that the material can not escape from the insert body, the material can be arranged in a bag or the insert body can be provided with a closure made of paper or a material based on cellulose.

From US Pat. No. 5,169,591, various generic insert bodies are known, which each have an impact area which is surrounded by boundary walls. Thus, inter alia, it is proposed to make the boundary walls obliquely outward or concave, so that the impinging casting steel does not squirt out of the insert body in an uncontrolled manner. The boundary walls should therefore form a peripheral roof, which forms an inlet opening for the inflowing cast steel and should throw back the upwardly splashing cast steel down. In a further embodiment of an insert body disclosed by US Pat. No. 5,169,591, the impact area is oriented obliquely to the base area of the intermediate container, as a result of which the impinging cast steel is to be deflected to the side. For this purpose, this insert body on its one side, to which the pouring stream is deflected, no boundary wall. It has been found that the insert bodies disclosed in US Pat. No. 5,169,591 do not reliably prevent uncontrolled spraying of the cast steel. This is due to the fact that formed by the boundary walls upper inlet opening for the casting steel must be kept larger than the diameter of the pouring stream, so that it can always reach safely into the insert body, without impinging on the boundary walls, whereby the casting steel would certainly splash out of the intermediate housing.

European patent EP 0 790 873 also discloses a baffle plate for an intermediate vessel made of refractory material, the baffle plate having a baffle surface surrounded by side walls which in turn form an upper surface which forms the inlet opening for the inflowing cast steel. It is essential in this baffle plate that in each case a right angle is formed between the side walls and the baffle surface and between the side walls and the upper surface and / or the inlet opening has a rectangular shape. Also in this baffle plate, the problem arises that the inlet opening must be selected to be larger than the diameter of the inflowing pouring stream, so that it is reliably prevented that the pouring stream does not miss the inlet opening.

Object of the present invention is therefore to develop a generic insert body such that the inlet opening is the same size or only slightly larger than the cross section of the inflowing pouring stream, so that uncontrolled splashing out of the casting steel from the insert body upwards is avoided.

This object is achieved with an insert body according to the features of claim 1. Further advantageous embodiments of the insert body according to claim 1 result from the features of the dependent subclaims.

The idea underlying the invention is that the insert body has a closed lid, which is partially destroyed or opened only by the impinging cast steel, so that the cast steel can get into the insert body. By this measure, the jet of the cast steel can in principle impinge on any point of the lid of the insert body, so that no special measures for accurate pouring of the cast steel must be made and the filling of the intermediate container designed a total of simpler. The lid is this advantageous thin-walled design. It may alternatively or additionally be perforated and / or have predetermined breaking points, so that it only breaks up where the cast steel impinges. The predetermined breaking points can in principle be arranged arbitrarily. Thus, it is possible to arrange the predetermined breaking points as transverse and longitudinal lines. Likewise, the predetermined breaking points can form concentric circles, ellipses, rectangles or polygons. The same applies of course to the perforations, e.g. can be formed by means of small holes. The holes are advantageous so small diameter to be dimensioned that the sprinkling of the impact surface upwards casting steel can not pass through the remaining holes in the lid outside.

The lid area, which has not been torn into the insert body by the cast steel, advantageously remains existing until the insert body is almost or completely filled. The lid is advantageous during or after completion of the filling process of the insert body melted so that the cast steel can run out over the edge of the insert body. The basic idea here is that it no longer comes to spraying the casting steel when it is filled into an already filled container. Similarly, it is also possible that the lid is not completely melted, but is broken away from the pressing from below cast steel to the outside, so that the way for the cast steel up from the insert body is free.

In any case, at least the lid material of the insert body should be of the same or at least similar nature and quality as the cast steel itself so that it does not contaminate the casting steel. Due to the small dimensions and the particular thin-walled design of the lid, however, there will be no significant contamination when a completely different material is used for the lid.

It is of course possible to design the inner walls and the impact surface of the insert body as desired in order to achieve a specific flow of the cast steel.

The lid can be bent around the top edges of the side walls so that it is secured against loss. However, it is also possible to fix the lid by means of fasteners, e.g. in the form of screws on the insert body or its side walls to attach.

It is also possible that in the pot-shaped insert body rests a closed container, which is supported with its outer walls on the inner walls of the insert body. The container forms with its upper wall the lid of the insert body. The container can be easily used from above and is particularly thin-walled, so that it melts during filling of the insert body and mixes with the casting steel. It is also possible to fill the container with a fluid, in particular a gas, such as argon, so that the casting steel does not come into contact with oxygen, and thus there is no unwanted oxidation of the steel. The shape of the insert body and the container is again in principle arbitrary selectable.

Exemplary possible embodiments of the insert body according to the invention will be explained in more detail below with reference to drawings.

Fig. 1:

Einen Zwischenbehälter mit einliegendem Einlegekörper;

Fig. 2:

Querschnitt durch einen erfindungsgemäßen Einlegekörper im noch nicht vollständig gefüllten Zustand;

Fig. 3:

Querschnitt durch den Einlegekörper gem. Fig. 2 im fast vollständig gefüllten Zustand;

Fig. 4:

Querschnitt durch einen überlaufenden Einlegekörper gem. der Figuren 2 und 3;

Fig. 5:

Einlegekörper mit aufgeschraubtem Deckel;

Fig. 6:

Einlegekörper mit um die Stirnseiten der Seitenwände umgebogenen Deckel;

Fig. 7:

Einlegekörper mit von der Seite in einen Schlitz eingeschobenen Deckel;

Fig. 8:

Einlegekörper mit eingelegtem geschlossenen Behälter;

Fig. 9:

Querschnitt durch eine erste Ausführungsform eines Deckels für einen Einlegekörper;

Fig. 10:

Querschnitt durch eine zweite Ausführungsform eines Deckels für einen Einlegekörper;

Fig. 11:

Draufsicht auf den Deckels gem. Figur 10;

Fig. 12:

Draufsicht auf eine dritte mögliche Ausführungsform eines Deckels;

Fig. 13:

Querschnitt durch eine weitere Ausführungsform mit eingeschlossenem Behälter und nach innen und unten gerichtetem Kragen;

Fig. 14:

Querschnitt durch einen Einlegekörper gem. Figur 13 kurz nach dem Beginn des Einfließens.

Show it:

Fig. 1:

An intermediate container with inlaid insert body;

Fig. 2:

Cross section through an insert body according to the invention in not yet completely filled state;

3:

Cross section through the insert body acc. Fig. 2 in the almost completely filled state;

4:

Cross section through an overflowing insert body acc. Figures 2 and 3;

Fig. 5:

Insert body with screwed lid;

Fig. 6:

Insert body with bent over the end faces of the side walls lid;

Fig. 7:

Insert body with inserted from the side into a slot cover;

Fig. 8:

Insert body with inserted closed container;

Fig. 9:

Cross-section through a first embodiment of a lid for a loading body;

Fig. 10:

Cross-section through a second embodiment of a lid for a loading body;

Fig. 11:

Top view on the lid gem. Figure 10;

Fig. 12:

Top view of a third possible embodiment of a lid;

Fig. 13:

Cross-section through another embodiment with enclosed container and inwardly and downwardly directed collar;

Fig. 14:

Cross section through an insert body gem. Figure 13 shortly after the beginning of the inflow.

1 shows a perspective view of an intermediate container 1, as used for example in continuous casting. The intermediate container has an upper opening 1a, over which the casting steel 3 passes by means of a spigot 2 in the inserted in the intermediate container 1 insert body 4. The insert body 4 according to the invention has a cover 4d which is partially destroyed by the jet of the cast steel 3 when it strikes the cover 4d. As soon as the insert body 4 is completely filled, the cast steel 3 flows over the edges of the side walls of the insert body 4 and reaches the bottom 1b of the intermediate container 1. The cast steel 3 then passes through openings 1c into molds or tools (not shown).

FIG. 2 shows a cross section through an insert body 4 according to the invention, as has already been shown in FIG. The insert body 4 has a bottom 4e, which forms the baffle surface 4f for the impinging cast steel 3. The baffle 4f is bounded by the side walls 4a of the insert body 4. The insert body 4 is closed at the top by the lid 4d. Only the area of the lid 4d, which is hit by the jet of the cast steel 3, is destroyed, so that the steel 3c spouting away from the baffle 4f can reach against the side walls 4c and the lid 4d, but not out of the insert body. The cavity 4b of the insert body 4 is filled relatively quickly with the casting steel 3b, so that the surface 3a of the casting steel accumulating in the insert body rises rapidly and, as shown in FIG. 3, reaches the lid 4d. The lid is made of a similar or identical material to the cast steel 3, so that the lid 4d melts due to the hot cast steel 3 and clears the path for the cast steel from the insert body, as shown in FIG. The cast steel then flows over the side edges 4g of the side walls 4a of the insert body 4 and enters the intermediate container, not shown.

FIG. 5 shows an alternative embodiment of an insert body 104 according to the invention, with a baffle surface 104f, sidewalls 104a and a cavity 104b. On the end faces 104g of the side walls 104a, the in particular thin-walled cover 104d is fastened by means of screws.

FIG. 6 also shows an alternative embodiment of an insert body 204 with bottom 204e, which forms the curved baffle 204f, which in the middle has an elevation sloping towards the side walls 204a, through which the impinging cast steel is discharged to the sidewalls 204a. The end faces 204g of the side walls 204a are shown rounded off by way of example. Of course, they can also be edged. The lid 204d is bent around the end faces 204g and engages behind the outwardly directed side walls positively, whereby it is securely held on the insert body.

FIG. 7 shows a further possible embodiment of an insert body 304 according to the invention, wherein here the lid 304d is pushed laterally into a slot 304m, which is worked into the inwardly directed end faces 304g of the side walls 304a, with its outer edges 304n. The side walls 304a are curved so that the cast steel impinging on the inner walls 304c is deflected downward, in particular, from the upper part of the side walls 304a.

FIG. 8 shows an embodiment in which in the insert body 404 a vessel or closed container 404p rests, which with its upper wall forms the lid 404d of the insert body 404. The container 404q is supported with its outer walls on the inner walls 404c, 404f of the insert body 404. The side walls 404a are directed outwardly so that the container 404p is easily insertable from above into the insert body 404. The container 404p may be filled with a gas 404q for corrosion protection. In particular, the container 404p may be thin-walled in the lid region 404d so that it can melt relatively easily.

Figures 9 to 12 show possible embodiments of lids for insert body according to the invention. Thus, FIG. 9 shows a cross section through a cover 6, whose region 6b, which is to be pierced by the cast steel, has a thin-walled construction, the region surrounding the region 6b being slightly thicker. The transition from region 6a to region 6b can in principle be of any desired design and is illustrated here in a simplified bevelled manner.

FIG. 10 shows a cross section through a further possible embodiment of a cover 7 which has perforations in the form of blind bores or recesses 7b. A possible arrangement of the perforations 7b is shown in FIG. 11, wherein the region 7c to be broken by the casting steel is surrounded by perforations 7b arranged in a circle. If the cast steel now strikes the region 7c, the cover is broken along the line formed by the perforations 7b, leaving only the regions 7a of the cover intact. Likewise, the isolated perforations can also be replaced by continuous break lines or combined with them.

Figure 12 shows an embodiment of a lid 8 in which perforations 8b are arranged in rows and columns. Circular the incident beam 3a of a casting steel 3 is shown. The beam 3a will break the portion 8c of the lid 8 along the line 8d which connects the perforations 8b closest to the beam to the lid 8 so that only the portions 8a which have an optimally large reflection area for that of the Impact surface of the insert body high-profile cast steel forms.

FIGS. 13 and 14 show a further possible embodiment of an insert body 504 according to the invention. The insert body 504 has a bottom plate 504e, which is adjoined by a peripheral boundary wall 504a which extends vertically upwards. At the upper edge of the boundary wall 504a, an inwardly and downwardly directed collar 504g is formed, which forms with its upper side surface 504g 'a kind of funnel, so that a possibly erroneously oriented pouring stream is still directed into the insert body 504. The insert body can be formed as a circular vessel, wherein the lid 504d may be formed as a cone. For example, the lid may be poured into the collar during the manufacturing process of the insert body 504. In a preferred embodiment, however, the funnel-shaped or conical lid is part of a container 504p, which consists entirely of a same or similar material as the cast steel. The container is then used to make the insert body as an inner mold. The free ends 504g "of the sidewall 504a may be formed as tips, thereby increasing the funnel formed by the collar 504g. The interplay of the circumferential inwardly and downwardly directed collar 504g and the funnel-shaped lid 504d will produce the pouring cast steel The cover 504d melts after some time, and then the cast steel from the side wall and its molded collar in the direction of the pouring pouring jet is directed (arrows) The cover, in particular the tip of the cone or funnel, can also be filled with gas may have perforations, for example in the form of holes, so that the lid is only partially destroyed by the impinging pouring stream and forms a defined opening. Instead of perforations, one or more peripheral material weakenings, for example in the form of at least one groove, may also be provided. A groove has the advantage that the container remains closed and thus can be filled with a gas.

It is, as already mentioned, of course, possible to adapt the shape and geometry of the insert body together with its lid and its side walls and impact surface the prevailing conditions, always pay attention to an upper closure means of the open or stopped lid.

Claims (23)

1. Insert for protecting the surface of impact of a casting steel in a metallurgical vessel, in particular in a tundish for continuous casting, with boundary walls surrounding the region of impact, which together with the surface of impact constitute a trough, characterised in that the insert (4, 104, 204, 304, 404, 504) exhibits a cover (4d, 104d, 204d, 304d, 404d, 504d, 6, 7, 8) sealing the trough upwardly, the cover being capable of being partly destroyed by the casting steel (3, 503) reaching the insert (4, 104, 204, 304, 404, 504).
2. Insert according to Claim 1, characterised in that the surface of impact and also the boundary walls are made of a refractory material and in that the cover is made of a material that is identical to or similar to the casting steel.
3. Insert according to Claim 1 or 2, characterised in that the cover is thin-walled.
4. Insert according to one of the preceding claims, characterised in that the cover (6, 7, 8) is perforated and/or exhibits predetermined breaking-points.
5. Insert according to one of the preceding claims, characterised in that the cover exhibits at least one opening, in particular a small window-like opening.
6. Insert according to one of the preceding claims, characterised in that after or during the filling of the insert (4, 104, 204, 304, 404) the cover fuses or is broken open by the casting steel.
7. Insert according to one of the preceding claims, characterised in that the cover is constituted by a plate, in particular a thin-walled plate, which rests on the upper end faces of the boundary walls.
8. Insert according to Claim 7, characterised in that the plate (104d) is fastened to the boundary walls (104a), in particular to the end faces (194g) thereof, by means of fastening means (105).
9. Insert according to one of Claims 7 or 8, characterised in that the plate exhibits on its lateral regions at least one collar, in particular a moulded-on collar, which at least partly encompasses at least one of the boundary walls from inside and/or outside.
10. Insert according to one of Claims 1 to 6, characterised in that a container (404p, 504p) made of a material that is identical to or similar to the casting steel is located in the insert, said container constituting the cover of the insert (4, 104, 204, 304, 404, 504).
11. Insert according to Claim 10, characterised in that the container (404p) is closed and bears against the surface of impact (404f) and against the periphery (404c) of the insert (4, 104, 204, 304, 404) at least in certain regions, the surface shape of the container being adapted, in particular, to the shape of the surface of impact and/or to the shape of the boundary walls.
12. Insert according to Claim 10 or 11, characterised in that the container exhibits at least one moulded-on or welded-on collar protruding outwards which at least partly encompasses at least one of the boundary walls.
13. Insert according to one of Claims 10 to 12, characterised in that a gas or gas mixture (404q) which comes into contact with the inflowing casting steel is present in the container (404p).
14. Insert according to one of the preceding claims, characterised in that the surface of impact is curved, honeycombed and/or formed in oblique manner in relation to the horizontal.
15. Insert according to Claim, characterised in that the boundary walls diverge outwards towards the upper side of the insert (4, 104, 204, 404).
16. Insert according to one of the preceding Claims 1 to 14, characterised in that the boundary walls (303a) are, in particular, concavely vaulted, by virtue of which the boundary walls (304a) constitute a part of the cover of the insert (304).
17. Insert according to one of the preceding Claims 1 to 14, characterised in that the boundary walls (504a) extend perpendicularly upwards, exhibiting an inwardly directed collar (504g) at their upper end.
18. Insert according to Claim 17, characterised in that the collar additionally extends downwards in the direction of the surface of impact (504f).
19. Insert according to Claim 17 or 18, characterised in that with its inwardly directed collar (504g) and/or with its cover (504d) the insert constitutes a funnel.
20. Insert according to Claim 19, characterised in that the lateral boundary walls (504a) with their free ends (504g'') constitute a portion of the funnel.
21. Insert according to one of Claims 17 to 20, characterised in that the cover is conical, dished or planar.
22. Insert according to one of Claims 17 to 21, characterised in that the cover is held by the collar, in particular is enveloped by the latter.
23. Insert according to one of Claims 17 to 22, characterised in that the insert exhibits a container (504p) made of a material that is identical to or similar to the casting steel, the container exhibiting a bottom, in particular a flat planar bottom, with boundary walls attached thereto, and the container (504p) exhibiting a cover (504d) which is formed inwardly and at the bottom in the manner of a cone.

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