EP1805330A1

EP1805330A1 - Tapping tube for a metallurgical fusion pot

Info

Publication number: EP1805330A1
Application number: EP05783886A
Authority: EP
Inventors: Roland Pungersek; Roland Lanzenberger; Manfred Slamenik
Original assignee: Refractory Intellectual Property GmbH and Co KG
Current assignee: Refractory Intellectual Property GmbH and Co KG
Priority date: 2004-10-18
Filing date: 2005-09-16
Publication date: 2007-07-11
Also published as: AR051219A1; US20070216073A1; CA2563472C; JP2008516772A; DE102004050701B3; KR20070068304A; BRPI0513000A; CN1973054A; CA2563472A1; WO2006042597A1

Abstract

The invention relates to a tapping tube for a metallurgical fusion pot. The aim of the invention is to provide a tapping tube which minimises possible downtime and enables essentially identical tapping durations during the use of the tapping tube. To this end, the tapping tube functionally divides into two parts, namely a first part embodied according to prior art, and a second part that can be connected to the first part in an easily exchangeable (replaceable) manner, thus forming a complete tapping tube. According to the invention, the section of the tapping tube relating to the flow is the outlet end. The cross-section of the outlet end determines the outflow quantity and thus the outflow duration (tapping duration) of the metal melt.

Description

Tapping tube for a metallurgical melting vessel

Description

The invention relates to a tapping tube for a metallurgical Schmelz¬ vessel. A metallurgical melting vessel is understood to mean an aggregate in which a metallurgical melt is produced, treated and / or transported, for example a converter or an electric arc furnace.

In this case, a molten metal in the melting vessel is passed through the tapping tube in a downstream unit. For example, the steel is fed from the converter via a ladle to a downstream continuous casting plant. The molten metal should be transported as possible without contamination. For example, contact with the ambient atmosphere (oxygen, nitrogen) should be avoided, as should slagging.

From EP 0 057 946 B1 a converter tap is known, which - in the axial direction - is composed of a plurality of interconnected refractory blocks or disks. With the same geometry, the converter tap can also be monolithic. Figure 1 shows this prior art, which has long been proven in the market. The central passage for the molten metal may be conical, cylindrical or stepped from the inlet end to the outlet end. In any case, when passing the molten metal, erosions very quickly occur at the boundary wall of the passage channel, whose cross-section thus constantly increases during operation, as shown schematically in FIG.

It will be appreciated that as the cross-section of the passageway changes, the amount of melt per unit time passing through the tapping tube will vary. This change is largely uncontrolled because the removal of refractory material is also largely uncontrolled.

It has therefore been tried to repair tapping pipes of the type mentioned after a certain tapping time, for example, by introducing a cylindrical template in the extended by erosion Through-channel and encapsulation of the template with a refractory mass. This process is time consuming and associated with the hot furnace unit with considerable difficulties.

The object of the invention is to provide a tapping tube which, while minimizing possible downtimes, enables as far as possible equal tapping times during the service life of the tapping tube.

The core idea of the invention is to functionally divide the tapping tube into two parts, namely a first part, which may be formed according to the prior art, and a second part, which can easily be exchanged (interchangeable) with the first part, namely under training a complete tapping pipe.

The invention is based on the finding that the strömungs¬ technically relevant portion of the tapping pipe is the outlet end. The cross section at the outlet end determines the amount of discharge and thus the flow time (tapping time) of the molten metal. This part lies "outside", namely furthest away from the molten bath in the metallurgical vessel, so that in this case the relatively lowest temperatures prevail anyway, which facilitates the changeability of a corresponding tapping part.

The basic idea of the invention is illustrated in FIG. 3 on the basis of FIGS. 1 and 2. It can be seen that the upper part of the Abstiches, starting from the inlet end E, has been adopted unchanged from the prior art, wherein in Figure 3 a on eräher¬ 2 of the state of wear is shown.

The essential difference from the prior art is that an outlet-side end A of the tapping pipe is designed as a separate, auswechsel¬ Bares component B, which is sealingly connected to the adjoining part of the tapping tube, as will be shown in detail yet.

The replaceable component B, which essentially has a cylindrical shape, has a passage D 1 whose cross-sectional area corresponds to a desired cross-section of the non-worn passage D.

Of course, in the region of the passage D 1, too, the refractory material will wear out and thus increase in cross-section over time. As soon as this cross-sectional enlargement has reached a certain value, however, the component B is exchanged at short notice without having to make or make any changes to the upstream section (hereinafter referred to as upper section) of the tapping tube. Although after installation of the new component B arises in the transition region to the upper tapping pipe part an annular step S, but this is deliberately accepted, because a repair of the upper part of the tapping pipe for the reasons mentioned is unacceptable and technologically not necessary, because the tapping time and the mass flow of the tapped molten metal are oriented exclusively at the cross section of the passage channel at the outlet end A. It goes without saying that the connection region between the exchangeable part B and the remaining section of the tapping pipe must be tight on the one hand, but must also be such that the component B is easily removable. For this purpose, solution proposals are presented below.

It is also to be understood that the "loose" component B must be held in the assembly shown in Figure 3 so as not to come off the upper portion of the tapping tube 14. To this end, the invention proposes various solutions, which are also presented below.

In its most general embodiment, the invention then comprises a tapping tube for a metallurgical melting vessel having the following features:

the tapping pipe has a passage for molten metal, which connects an inlet end to an outlet end,

starting from the outlet end, the tapping pipe comprises a cylin derförmigen end portion, which, adjacent to the passageway, designed as a separate cylindrical component, the component is at its, the outlet end of the tapping um¬ comprehensive first end for stationary, but releasable mounting of the component in formed a holding device, the component has at its second end a, in the direction of the inlet end facing end face, which bears in a holding position of the component sealingly against an axially adjacent portion of the Abstich¬ tube. Cylindrical includes cross sections with circular cross section, but also all other cross sectional geometries. This applies to both inner and outer cross sections of the pipe. In the axial direction (flow direction of the melt), the tube may be cylindrical or conical. Other contours are possible, for example, a stepped surface. In addition to a circular cross-section, inner and outer cross sections can be polygonal or oval. Any polygon shape is possible.

Decisive for the tap pipe according to the invention is that the mentioned replaceable component the passage D (D l) circumferentially limited.

This includes embodiments, as shown in Figure 3, in which the component B extends over the entire cross-sectional area of the tapping tube. However, this also includes embodiments in which the component is inserted in the manner of a built-in sleeve in the lower (outlet side) end portion of the tapping tube, as will be graphically shown below.

The cylindrical component can have any inner cross section. For example, the passageway in the region of the component has a round or oval inner cross section. The cross-sectional area should correspond to the desired cross-sectional area with regard to the desired mass flow and the desired tapping time.

The passageway in the region of the component can have a constant internal cross-section over the height of the component, but it can also be slightly tapered or stepped at the outlet end.

As already mentioned, the cylindrical component can be inserted into an outer cylindrical end section of the tapping tube. The Tapping tube receives in this way its desired length unchanged. At the outlet end only an exchangeable sleeve is arranged interchangeable.

For a given length of the tapping tube this can also, as shown in Figure 3, be shortened, the replaceable component after installation of the tapping tube returns its original length.

The attachment of the replaceable component on or in the other part of the tapping tube can be done in different ways. One possibility is to form the component circumferentially with an external thread, which cooperates with a corresponding internal thread. This internal thread can be arranged as a separate component in the region of the outlet end of the tapping tube on the associated metallurgical vessel. However, it may also be part of the outlet end of the tapping pipe, in particular in the case of the mentioned component used.

Instead of a threaded connection, a bayonet lock is also possible.

According to one embodiment, the cylindrical exchange component on its outer side or at the outlet end stops for a pressure medium, which can act in the direction of the inlet end to the component.

The pressure means may for example be springs which are arranged on a holding device, which in turn is fastened to the outside of the metallurgical vessel. The decisive factor is that the replacement component is held under pressure in the direction of the inlet of the tapping pipe in such a way that a tight connection with respect to the remaining part of the tapping pipe results. The corresponding holding means are therefore arranged in particular on the free lower end face or on the outer circumference of the component.

The tightness can be improved if the end face has a surface profiling on the fitting-side end of the component, ie is not smooth. Such a profiling can consist of individual, discrete nubs or webs. Likewise, the profiling can also consist of concentric or spirally arranged web-like elevations.

In the same way, alternatively or cumulatively, the surface of the tapping tube can be formed, against which the end face of the interchangeable component is pressed.

Another alternative provides to place a seal between the corresponding surfaces of tapping tube and component. In particular, when the corresponding surface sections of the refractory material are more or less planar, it is advisable to form the generally annular seal with surface profilings, as described above.

These profiles, irrespective of whether they are formed from the refractory material and / or are part of the seal, allow a certain elasticity and thus deformability when the component is connected to the remaining portion of the tapping tube. As a gasket material, for example, graphite is suitable because it also has a corresponding temperature resistance. The seal can also be provided as a sealant, for example as an emulsion of flake graphite and oil.

The abutment surface (end face) of said component on the ceramic section of the remaining tapping tube can be flat (in particular perpendicular to the central longitudinal axis of the tapping tube) or domed, in particular domed, that is to say curved in the direction of the inlet end.

The component can simultaneously have a temporary barrier for so-called feed slag. This feed slag flows when tilting the associated converter in the tapping pipe (and subsequently in the downstream metallurgical vessel), which is undesirable. The invention therefore provides for the component to be formed with a blocking element which temporarily fills the inner cross-section (flow channel). In this case, "temporary" means that the blocking effect only has to be very short, for example a few seconds, before metal melt enters the tapping channel during tapping.

Such a blocking element can be, for example, a thin metal plate, or a type of cup, which are placed in the flow channel of the component, for example by means of spring arms (claws) on its peripheral surface.

The length of the component is basically arbitrary. The decisive factor is - as stated - the outlet cross section at the outlet end. However, the service life of the component can be increased if its length corresponds to at least 1.5 times the smallest inner diameter, wherein a ratio of 1.5 to 3 is generally sufficient. This length is too important to ensure the desired characteristic of the outgoing Schmelz¬ flow. In particular, a uniformly exiting melt stream is achieved.

By slightly changing the end piece, the tapping pipe described allows for the most part constant tapping times and thus an improved availability of the smelting unit. The change of the end-side component can be automated. Since the exchange takes place from the outside, it is easy and short to perform. The installation takes place in such a way that the tapping pipe at the outlet end terminates more or less flush with the outer wall of the metallurgical vessel.

The end-side component can be formed from the same material as the rest of the tapping tube. Both sections can also be formed from different varieties. In this case, the component can be made of a particularly wear-resistant material quality.

Different thermal expansions of different materials can be compensated by the mentioned sealing area or an elastic support for the component.

Other features of the invention will become apparent from the features of the claims and the other application documents.

The invention will be explained in more detail below with reference to various Ausführungsbei¬ games. In each case, in a diagrammatic representation,

FIG. 4 is a partial sectional view of an end portion of a tapping tube; 5 shows a plan view and a section through the surface 24 of the exchangeable component of the tapping tube according to FIG. 4, FIG.

FIG. 6: a partial sectional view of a further embodiment of a tapping tube, wherein only the lower part is shown.

In the figures, the same or equivalent components are shown with the same reference numerals.

FIG. 4 shows the lower part of a tapping tube 10, which is assembled in a refractory lining of a converter 12, which has a metal jacket 14 on the outside. All this is state of the art and therefore will not be further described.

Starting from the outlet end 16 of the passage D, an end portion 18 of the tap tube 10 on the inside an extended Aus¬ saving 20, in this case with a cylindrical wall surface. Immediately adjacent to the outlet end 16, a metal ring 22 is glued in the wall portion of the End¬ 18, which has an internal thread.

This internal thread cooperates with an external thread, which is formed circumferentially on a mounting part B. The component B is cylindrical. The outer diameter of the component B corresponds to the inner diameter of the recess 20. Thus, the component B can be placed along the threads described in the recess 20 until it is flush with the end portion 1 8 and the metal shell 14 at the outlet end 16. The component B has a central passage D channel with a circular cross section, which corresponds to a desired cross-section of the passage D at the outlet end of the tapping tube 10. For connection to the section 1 8, a graphite seal 28 is arranged between an upper end face 24 of the component B and the corresponding stop face 26 of the section 18, which was compressed when screwing the component B into the recess 20, the size in the drawing the seal 28 is exaggerated.

If the tapping tube 10 is worn, as shown in FIGS. 2, 3, whereby the component B also wears, only the component B is exchanged so that essentially an arrangement results, as shown in FIG. In this case, the component B is unscrewed from the recess 20 and screwed a new component with a defined passage D l.

FIG. 5 shows, in a section (bottom) and in a plan view (top), the formation of the end face 24 of the component B with concentric, rib-like ribs 24r, wherein the seal 28 can advantageously press into the valleys formed between the ribs 24r and so that the sealing effect is optimized.

In the embodiment according to FIG. 6, the component B is not arranged in a recess 20 of the end section 18 of the tapping tube 10. The upper part of the tapping tube 10 is shortened by the length (height) of the component B, so that the abutment surface 26 for the component B extends over the entire wall thickness of the tube 10.

The component B with a central passage D l with circular cross-section has on the outside a truncated cone shape and is arranged in a korrespon¬ dierenden metal sleeve 30 having a radially encircling web 32. Against this web 32 are holding arms 34, which are pressed by compression springs 36 in the direction of the upper part of the tapping tube 10. The springs 36 in turn are mounted on arms 38 which are hinged to the metal shell 14 of the metallurgical vessel (not shown in detail). Projecting parts thus form a holding device for the component B.

In this way, the component B is pressed under the action of the springs 36 with its upper end face 24 against the corresponding stop surface 26 of the upper part of the tapping tube 10. Between the surfaces 24, 26, which can also be formed profiled, in turn, a seal can be arranged, for example, a graphite foil.

In case of wear (indicated by the dashed line L), the component B can be exchanged in the short term by the holding device is released. The new component B (with through-channel D l) is then fixed again with the holding device and then secures an outflow cross-section with a defined nominal diameter for the following tapping batches.

Even with further wear of the tapping tube 10 (symbolized by a point line P), the upper part of the tapping tube 10 remains unchanged. However, the component B is exchanged again as soon as it has reached the state of wear represented by the dashed line L again.

FIG. 6 also shows diagrammatically a cup-shaped obturator 40, which consists of a thin sheet whose peripheral edge rests on the upper end face 24 of the component B when it is pressed against the corresponding stop face 26. The locking member 40 Prevents slag from entering through the flow channel D into a downstream melting vessel during casting. It can only penetrate a small amount of slag in the passage D channel to Sperr¬ organ 40. Once the feed slag is passed by the tilting of the melting vessel at the inlet end of the tapping tube 10, there is now only melt above the inlet end. Now, the slag located in the inlet-side part of the tapping pipe 10 can either float up or, after the obturator 40 has melted, flow out of this part of the slag. Subsequently, only melt flows through the tapping 10th

The blocking element shown represents a possible structural solution. It is crucial that with the change of the component B at the same time a blocking member of the same functionality can be installed, which then causes a temporary shut-off of the flow channel D.

Claims

Tapping tube for a metallurgical melting vessel

P a n t a n s p r e c h e

A tapping pipe (10) for a metallurgical melting vessel (12) having a passageway D for a molten metal connecting an inlet end E to an outlet end A, wherein, starting from the outlet end A, an associated cylindrical end portion of the tapping pipe (10) adjacent to the passageway D , is designed as a separate cylindrical component B, which at its, the Aus¬ current A of the tapping pipe (10) comprehensive first end for orts¬ firm, but releasable mounting of the component B in a Haltevor¬ direction (22; 34) is formed and at its second end a, in the direction of the inlet end E facing end face (24) auf¬ has, which bears in a holding position of the component B sealingly against an axially adjacent portion (26) of the tapping tube (10).

2. Tapping tube according to claim 1, the cylindrical component B has a, a desired cross-section of the passage D corresponding to the inner cross-section.

3. Abstichrohr according to claim 1, wherein the inner cross section of the component B is constant over its height.

4. Tapping tube according to claim 1, the component B rests in an outer cylindrical end portion of the tapping tube (10).

5. tapping pipe according to claim 1, the component B, the outlet end A adjacent, circumferentially has an external thread.

6. tapping pipe according to claim 1, the component B on its outer side or at the outlet end A stops (32) for a pressure medium (34, 36) which acts in the direction of the inlet end E on the component B.

7. Tapping tube according to claim 1, wherein the end face (24) at the second end of the component B has a surface profiling (24r).

8. tapping tube according to claim 7, wherein the surface profiling (24r) consists of concentric to each other or spirally extending web-like ribs.

9. tapping tube according to claim 1, wherein the end face (24) at the second end of the component B describes an annular portion of an imaginary sphere.

10. tapping tube according to claim 1 with a seal (28) between the end face (24) at the second end of the component B and the axially adjacent portion (26) of the tapping tube (10).

1 1. Tapping tube according to claim 10, wherein the seal consists of a sealant.

12. Abstichrohr according to claim 10, wherein the seal consists of an annular sealing film with one or both sides structured surface.

13. Tapping tube according to claim 1, wherein the end face (24) at the second end of the component adjacent portion (26) of the tapping tube (10) is designed plan.

14. Abstichrohr according to claim 1 with a, the inner cross section of the component B temporarily filling blocking member (40).

15. Tapping tube according to claim 1, wherein the component B has a length which corresponds to the 1, 5 to 3 times the smallest inner diameter of the tapping tube (10).