EP0406208A1 - Preheating device for a molten metal casting nozzle and metal casting installation comprising such device - Google Patents

Preheating device for a molten metal casting nozzle and metal casting installation comprising such device Download PDF

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Publication number
EP0406208A1
EP0406208A1 EP90870094A EP90870094A EP0406208A1 EP 0406208 A1 EP0406208 A1 EP 0406208A1 EP 90870094 A EP90870094 A EP 90870094A EP 90870094 A EP90870094 A EP 90870094A EP 0406208 A1 EP0406208 A1 EP 0406208A1
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EP
European Patent Office
Prior art keywords
burner
nozzle
stopper
chamber
rod
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP90870094A
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German (de)
French (fr)
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EP0406208B1 (en
Inventor
Paul Naveau
Stéphan Wilmotte
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Centre de Recherches Metallurgiques CRM ASBL
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Centre de Recherches Metallurgiques CRM ASBL
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/14—Closures
    • B22D41/16—Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/005—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like with heating or cooling means
    • B22D41/01—Heating means
    • B22D41/015—Heating means with external heating, i.e. the heat source not being a part of the ladle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
    • B22D41/50—Pouring-nozzles
    • B22D41/60—Pouring-nozzles with heating or cooling means

Definitions

  • the present invention relates to a device for preheating a nozzle for casting a molten metal, in particular steel. It also relates to a metal casting installation equipped with this device.
  • a conventional installation for casting a metal essentially consists of a container containing the metal to be poured, and a mold in which the metal is poured and where it solidifies to the desired shape.
  • the container is generally a ladle and the mold an ingot mold in which ingots intended for rolling are produced.
  • the installation generally comprises an additional container, the distribution basket, arranged between the casting ladle and the ingot mold, which here has no bottom.
  • Each of these containers namely the ladle and the distribution basket in the case of continuous casting, is provided, at its bottom, with a pouring opening allowing the flow of molten steel to the next container or to the mold.
  • Certain containers, and in particular the distribution baskets usually have several pouring orifices.
  • a pouring orifice is materialized by a refractory brick, called pouring brick or bottom nozzle, housed in the refractory lining of the bottom of the container and pierced with a calibrated channel which constitutes the taphole. It is currently common for the bottom nozzle to be extended, towards the outside of the container, by a tube whose internal section is suitable for that of the tap hole. This tube, which is intended to immerse in the steel contained in the next container or in the ingot mold is often called a submerged nozzle or an external nozzle.
  • the inlet of the bottom nozzle is usually profiled in a seat on which is applied a pad, also profiled, intended to close the tap hole.
  • This pad or stopper is also made of refractory material.
  • Such a device in fact comprises a distributor plate, or dome, of refractory material, placed in the axis of the tap hole, between the bottom nozzle and the external nozzle. This dome obstructs the propagation of the flame from the burner to the bottom nozzle and consequently prevents adequate heating of this bottom nozzle as well as of the upper surface of the dome.
  • the object of the present invention is to provide a device which makes it possible, in a simple and reliable manner, to remedy the aforementioned drawbacks.
  • the preheating device according to the invention has virtually no bulk, and it is easy to position and orient with precision; it can also be used with the various types of existing casting devices, in particular with those which have been mentioned above.
  • a device for preheating a nozzle for casting a molten metal said nozzle being at least partly disposed in the refractory lining of the bottom of a metallurgical container, is characterized in that it comprises at least one burner which is arranged inside said metallurgical container and which is oriented towards the inlet section of said pouring nozzle and in that said burner is housed in a tube for protection against molten metal.
  • a so-called premix burner is advantageously used, that is to say a burner in which the mixing of the fuel and the oxidant takes place inside the burner.
  • said tube is a stopper for closing said pouring nozzle and said burner is arranged in a chamber formed inside said stopper, and the lower end of the stopper is pierced at least one channel communicating with said chamber.
  • the chamber extends in the longitudinal direction of the stopper rod, coaxial thereto, and the burner occupies an upper part of the chamber, the latter thus having a free volume in the region of the lower end of the distaff.
  • the burner can be provided, in the region of its outlet end, with centering and / or sealing means; these means are preferably constituted by a ring, placed at the outlet end of the burner, which ensures on the one hand the centering of the burner in said interior chamber and on the other hand the sealed separation between said free volume and the rest of the room where the burner is located.
  • said channel pierced in the lower end of the stopper has a section coaxial with the stopper and having a diameter less than that of said interior chamber.
  • lateral outlet channels are preferably provided, which surround said coaxial channel and which open into it at suitable angles.
  • the angle of inclination of these lateral channels with respect to the coaxial channel is advantageously less than 90 ° and preferably less than 60 °.
  • a sleeve is provided around the lower end of the protective tube, respectively of the stopper rod, in order to avoid any disturbance of the flame by external influences.
  • Fig. 1 shows a preheating device representative of the prior art of preheating a pouring nozzle.
  • a fragment of a bottom 1 of a basket for distributing continuous steel In this bottom fragment 1 is housed a bottom nozzle 2, which is extended downwards by an external nozzle 3.
  • the bottom nozzle 2 has, at the entrance of the tap hole 4, a rounded seat 5 on which comes apply the profiled lower end, or nose 6, of a stopper 7 of refractory material.
  • a burner 8 is arranged under the external nozzle 3, in alignment with the latter; the flame 9 of this burner can propagate over the entire length of the outer nozzle 3 and of the bottom nozzle 2, and reach the profiled nose 6 of the stopper rod 7.
  • a steel cooling device is placed between the bottom 1 and the outer nozzle 3.
  • This device comprises a dome 11 made of refractory material, intended to form a hollow jet of steel in the device 10. This dome 11 would prevent the flame of a lower burner from propagating to the bottom nozzle 2 and to the nose 6 of the stopper 7.
  • the preheating device comprises a hollow stopper rod 12, made of refractory material, inside which is placed a burner 13 directed from top to bottom, that is to say towards the seat 5 and the tap hole 4 of the bottom nozzle 2.
  • the flame 14 can then reach the upper surface of the dome 11, as well as the nozzle 3, which ensures a fluid flow of the steel towards the device 10.
  • Fig. 3 shows in more detail a preheating device according to the invention.
  • the cooling device 10 and the external nozzle 3, which are not part of the invention and which are moreover shown in FIG, have not been reproduced. 2.
  • This assembly is recalled by the dome 11, which is placed at the outlet of the tap hole 4 of the bottom nozzle 2.
  • the stopper 12 of refractory material is hollow; it has an axial chamber 15, in which is disposed a premix burner 13.
  • the axial chamber 15 extends beyond the head 16 of the burner in the direction of the lower end of the stopper; it thus forms a free volume 17, which communicates with the outside via an axial channel 18, of diameter substantially smaller than that of this free volume 17.
  • the channel 18 opens axially in the nose of the stopper; inclined lateral channels 19 are also provided, which open on the one hand into the axial channel 18 and on the other hand into the profiled part 6 of the stopper rod 12.
  • the burner is supplied with fuel and with oxidant, from preferably gas, by two pipes 21, 22 of small diameter.
  • the entire burner, with its supply lines, is preferably made of stainless steel.
  • the head 16 of the burner 13 is centered in the axial chamber 15 by means of a ring 2u, which also ensures a sealed separation between the free volume 17 and the upper or upstream part of the chamber 15.
  • the lower end of the stopper 12 can be surrounded by a sleeve 23, for example of frustoconical shape, which rests on the bottom 1 around the bottom nozzle 2.
  • the combustible and oxidizing gases pass through the pipes 21, 22 at high speed and thus ensure the cooling of these pipes and of the burner head 16.
  • the gas mixture arrives at high speed in the free volume 17 then, through the axial channel 18 and the lateral channels 19, the flame 14 leaves the lower end of the stopper 12 in the direction of the bottom nozzle 2.
  • the axial flame penetrates into the tap hole 4 and spreads to the dome, the upper surface of which it heats.
  • the side flames heat the seat 5 of the bottom nozzle 2.
  • the lateral channels 19 are inclined on the axial channel 18 at an angle less than 90 °, and preferably less than 60 °. This angle is chosen, according to the profile of the seat 5 and of the roundness 6, in such a way that the lateral channels 19 are directed towards the seat 5 during the period of preheating of the nozzle and that they are not obstructed by the steel when the stopper rod is applied to the seat 5.
  • the sleeve 23 is preferably made of low density ceramic fiber. It avoids the blowing of the flame 14 by gas or air eddies which can occur in the distributor basket. It also maintains a high temperature around the seat 5 by reducing heat loss. The height of the sleeve 23 must be sufficient to guarantee the desired protection.
  • the efficiency of preheating can also be influenced by the relative position of the burner 16 and the nose 6 of the stopper rod relative to the seat 5 of the nozzle to be preheated.
  • This position can be defined by the height H of the burner 16 and / or h of the nose 6 above the bottom 1 of the basket; this height depends in particular on the geometry of the nozzle 2 (diameter, radius of curvature of the seat).
  • the height H should be understood to be preferably between 300 mm and 600 mm, and that the height h should preferably be less than and 50 mm.
  • a bottom nozzle in graphite alumina was preheated, and a distribution dome, arranged as shown in Fig.3.
  • a flame supplied by the combustion of 3 m3 N / h of gas with 11 m3 N / h of air was used.
  • the purpose of the excess gas was to increase the stability of the flame and to avoid decarburization of the graphite alumina nozzle.
  • the height h was 20 mm and the height H was 470 mm; the sleeve was 300 mm high.
  • the dome and the nozzle had a temperature of the order of 1200 ° C., clearly sufficient to start casting the steel without risk of freezing.
  • the device of the invention allows a relatively long area to be heated with the same efficiency going from the seat 5 to the dome 11. It provides a high heating power, while guaranteeing good resistance to the temperature of the burner head. There is no problem of space or installation.
  • the invention is of course not limited to the embodiment which has just been described and illustrated. It also includes various modifications that a person skilled in the art could make to it, for example by using a refractory tube which is not the stopper stopper stopper. Furthermore, the device of the invention can be used for the preheating of conventional type casting nozzles having no metal distribution dome. Finally, the use of the device of the invention is not limited to continuous casting.

Abstract

This preheating device for a molten-metal casting nozzle (2), arranged in the refractory lining of the bottom (1) of a metallurgical vessel, comprises at least one burner (13) which is arranged inside the metallurgical vessel and which is oriented towards the inlet section of the casting nozzle (2). The burner is accommodated in a tube (12) for protection against the molten metal; this tube is preferably a stopper rod (tapping rod) (12) for closing the casting nozzle. The burner (13) is arranged in a chamber (15) provided inside the stopper rod (tapping rod) and the lower end of this stopper rod (tapping rod) (12) is pierced with at least one channel (18) communicating with the said chamber (15) and oriented so as to direct the flame of the burner (13) towards the nozzle (2) and towards the seat (5) of the stopper rod (tapping rod) (12). <IMAGE>

Description

La présente invention concerne un dispositif de préchauffage d'une busette de coulée d'un métal en fusion, en particulier de l'acier. Elle porte également sur une installation de coulée d'un métal équipée de ce dispositif.The present invention relates to a device for preheating a nozzle for casting a molten metal, in particular steel. It also relates to a metal casting installation equipped with this device.

Une installation classique de coulée d'un métal se compose essentiellement d'un récipient contenant le métal à couler, et d'un moule dans lequel le métal est coulé et où il se solidifie à la forme désirée.A conventional installation for casting a metal essentially consists of a container containing the metal to be poured, and a mold in which the metal is poured and where it solidifies to the desired shape.

Dans le cas de l'acier, le récipient est généralement une poche de coulée et le moule une lingotière dans laquelle on produit des lingots destinés au laminage. Dans la technique de la coulée continue, actuellement bien connue, l'installation comporte en général un récipient supplémentaire, le panier répartiteur, disposé entre la poche de coulée et la lingotière, laquelle n'a ici pas de fond.In the case of steel, the container is generally a ladle and the mold an ingot mold in which ingots intended for rolling are produced. In the technique of continuous casting, currently well known, the installation generally comprises an additional container, the distribution basket, arranged between the casting ladle and the ingot mold, which here has no bottom.

Pour la clarté de l'exposé, la description qui suit fera plus particulièrement référence à la coulée continue de l'acier. Il va de soi cependant que cette référence particulière n'entraîne aucune limitation de l'invention et que celle-ci est applicable à la coulée de tout métal en fusion ainsi qu'aux opérations de moulage en fonderie.For the sake of clarity, the following description will more particularly refer to the continuous casting of steel. It goes without saying, however, that this particular reference does not imply any limitation of the invention and that it is applicable to the casting of any molten metal as well as to molding operations in foundries.

Chacun de ces récipients, à savoir la poche de coulée et le panier répartiteur dans le cas de la coulée continue, est pourvu, dans son fond, d'un orifice de coulée permettant l'écoulement de l'acier en fusion vers le récipient suivant ou vers la lingotière. Certains récipients, et en particulier les paniers répartiteurs, comportent habituellement plusieurs orifices de coulée.Each of these containers, namely the ladle and the distribution basket in the case of continuous casting, is provided, at its bottom, with a pouring opening allowing the flow of molten steel to the next container or to the mold. Certain containers, and in particular the distribution baskets, usually have several pouring orifices.

Concrètement, un orifice de coulée est matérialisé par une brique réfractaire, dite brique de coulée ou busette de fond, logée dans le garnissage réfractaire du fond du récipient et percée d'un canal calibré qui constitue le trou de coulée. Il est fréquent actuellement que la busette de fond soit prolongée, vers l'extérieur du récipient, par un tube dont la section intérieure est appropriée à celle du trou de coulée. Ce tube, qui est destiné à plonger dans l'acier contenu dans le récipient suivant ou dans la lingotière est souvent appelé busette immergée ou busette extérieure.Concretely, a pouring orifice is materialized by a refractory brick, called pouring brick or bottom nozzle, housed in the refractory lining of the bottom of the container and pierced with a calibrated channel which constitutes the taphole. It is currently common for the bottom nozzle to be extended, towards the outside of the container, by a tube whose internal section is suitable for that of the tap hole. This tube, which is intended to immerse in the steel contained in the next container or in the ingot mold is often called a submerged nozzle or an external nozzle.

L'entrée de la busette de fond est habituellement profilée en un siège sur lequel vient s'appliquer un tampon, également profilé, destiné à obturer le trou de coulée. Ce tampon ou quenouille est également réalisé en matériau réfractaire.The inlet of the bottom nozzle is usually profiled in a seat on which is applied a pad, also profiled, intended to close the tap hole. This pad or stopper is also made of refractory material.

Il est bien connu, dans la pratique actuelle, de préchauffer les busettes avant la coulée, afin d'éviter tout risque de solidification d'acier dans une busette froide, qui pourrait ainsi être rapidement bouchée. On utilise à cet effet un brûleur disposé à l'extérieur du récipient et orienté de bas en haut dans le prolongement du trou de coulée.It is well known, in current practice, to preheat the nozzles before casting, in order to avoid any risk of solidification of steel in a cold nozzle, which could thus be quickly plugged. For this purpose, a burner is used, placed outside the container and oriented from bottom to top in the extension of the tap hole.

Cette disposition s'avère cependant peu pratique, car la mise en place du brûleur impose que l'on resérve un espace libre assez important entre les deux récipients. En outre, il n'est pas toujours aisé de positionner et d'orienter le brûleur avec précision pour lui assurer une efficacité de chauffage maximale. Par ailleurs, une telle disposition de brûleur n'est pas utilisable avec un dispositif de coulée du type décrit notamment dans le brevet LU-A-86688. Un tel dispositif comporte en effet un plateau répartiteur, ou dôme, en matériau réfractaire, placé dans l'axe du trou de coulée, entre la busette de fond et la busette extérieure. Ce dôme fait obstacle à la propagation de la flamme du brûleur vers la busette de fond et empêche par conséquent le chauffage adéquat de cette busette de fond ainsi que de la surface supérieure du dôme.This arrangement is, however, impractical, because the installation of the burner requires that a fairly large free space be reserved between the two containers. In addition, it is not always easy to position and orient the burner precisely to ensure maximum heating efficiency. Furthermore, such a burner arrangement cannot be used with a casting device of the type described in particular in patent LU-A-86688. Such a device in fact comprises a distributor plate, or dome, of refractory material, placed in the axis of the tap hole, between the bottom nozzle and the external nozzle. This dome obstructs the propagation of the flame from the burner to the bottom nozzle and consequently prevents adequate heating of this bottom nozzle as well as of the upper surface of the dome.

La présente invention à pour objet de proposer un dispositif qui permet, de manière simple et fiable, de remédier aux inconvénients précités. En particulier, le dispositif de préchauffage conforme à l'invention ne présente pratiquement aucun encombrement, et il est aisé à positionner et à orienter avec précision; il peut en outre être utilisé avec les divers types de dispositifs de coulée existants, en particulier avec ceux qui ont été mentionnés plus haut.The object of the present invention is to provide a device which makes it possible, in a simple and reliable manner, to remedy the aforementioned drawbacks. In particular, the preheating device according to the invention has virtually no bulk, and it is easy to position and orient with precision; it can also be used with the various types of existing casting devices, in particular with those which have been mentioned above.

Conformément à la présente invention, un dispositif de préchauffage d'une busette de coulée d'un métal en fusion, ladite busette étant au moins en partie disposée dans le garnissage réfractaire du fond d'un récipient métallurgique, est caractérisé en ce qu'il comporte au moins un brûleur qui est disposé à l'intérieur dudit récipient métallurgique et qui est orienté vers la section d'entrée de ladite busette de coulée et en ce que ledit brûleur est logé dans un tube de protection contre le métal en fusion.According to the present invention, a device for preheating a nozzle for casting a molten metal, said nozzle being at least partly disposed in the refractory lining of the bottom of a metallurgical container, is characterized in that it comprises at least one burner which is arranged inside said metallurgical container and which is oriented towards the inlet section of said pouring nozzle and in that said burner is housed in a tube for protection against molten metal.

A cet effet, on utilise avantageusement un brûleur dit à prémélange, c'est-à-dire un brûleur dans lequel le mélange du combustible et du comburant s'effectue à l'intérieur du brûleur.To this end, a so-called premix burner is advantageously used, that is to say a burner in which the mixing of the fuel and the oxidant takes place inside the burner.

Selon une réalisation intéressante du dispositif de l'invention, ledit tube est une quenouille de fermeture de ladite busette de coulée et ledit brûleur est disposé dans une chambre ménagée à l'intérieur de ladite quenouille, et l'extrémité inférieure de la quenouille est percée d'au moins un canal communiquant avec ladite chambre.According to an interesting embodiment of the device of the invention, said tube is a stopper for closing said pouring nozzle and said burner is arranged in a chamber formed inside said stopper, and the lower end of the stopper is pierced at least one channel communicating with said chamber.

De préférence, la chambre s'étend suivant la direction longitudinale de la quenouille, coaxialement à celle-ci, et le brûleur occupe une partie supérieure de la chambre, celle-ci présentant ainsi un volume libre dans la région de l'extrémité inférieure de la quenouille.Preferably, the chamber extends in the longitudinal direction of the stopper rod, coaxial thereto, and the burner occupies an upper part of the chamber, the latter thus having a free volume in the region of the lower end of the distaff.

Dans ce volume libre débouchent d'une part le brûleur à prémélange et d'autre part ledit canal percé dans l'extrémité inférieure de la quenouille.In this free volume lead on the one hand the premix burner and on the other hand said channel pierced in the lower end of the stopper rod.

Selon l'invention, le brûleur peut être pourvu, dans la région de son extrémité de sortie, de moyens de centrage et/ou d'étanchéité; ces moyens sont de préférence constitués par une bague, posée à l'extrémité de sortie du brûleur, qui assure d'une part le centrage du brûleur dans ladite chambre intérieure et d'autre part la séparation étanche entre ledit volume libre et le reste de la chambre où se trouve le brûleur.According to the invention, the burner can be provided, in the region of its outlet end, with centering and / or sealing means; these means are preferably constituted by a ring, placed at the outlet end of the burner, which ensures on the one hand the centering of the burner in said interior chamber and on the other hand the sealed separation between said free volume and the rest of the room where the burner is located.

De manière également avantageuse, ledit canal percé dans l'extré­mité inférieure de la quenouille comporte un tronçon coaxial à la quenouille et présentant un diamètre inférieur à celui de ladite chambre intérieure.Also advantageously, said channel pierced in the lower end of the stopper has a section coaxial with the stopper and having a diameter less than that of said interior chamber.

A l'extrémité inférieure de la quenouille, il est de préférence prévu plusieurs canaux de sortie latéraux, qui entourent ledit canal coaxial et qui débouchent dans celui-ci sous des angles appropriés. Selon l'invention, l'angle d'inclinaison de ces canaux latéraux par rapport au canal coaxial est avantageusement inférieur à 90° et de préférence inférieur à 60°.At the lower end of the stopper rod, several lateral outlet channels are preferably provided, which surround said coaxial channel and which open into it at suitable angles. According to the invention, the angle of inclination of these lateral channels with respect to the coaxial channel is advantageously less than 90 ° and preferably less than 60 °.

Egalement selon l'invention, il est prévu un manchon autour de l'extrémité inférieure du tube de protection, respectivement de la quenouille, afin d'éviter toute perturbation de la flamme par des influences extérieures.Also according to the invention, a sleeve is provided around the lower end of the protective tube, respectively of the stopper rod, in order to avoid any disturbance of the flame by external influences.

D'autres particularités et avantages du dispositif de préchauffage conforme à l'invention apparaîtront par la description qui va suivre. Cette description, donnée à titre d'exemple, porte sur une réalisation particulière du dispositif de l'invention; elle se réfère aux dessins annexés, dans lesquels la

  • Fig. 1 montre, à titre de comparaison, un dispositif de préchauffage de la technique antérieure; la
  • Fig. 2 illustre le principe du dispositif de préchauffage conforme à l'invention; et la
  • Fig. 3 représente en détail une réalisation préférée d'un dispositif de l'invention.
Other features and advantages of the preheating device according to the invention will become apparent from the description which follows. This description, given by way of example, relates to a particular embodiment of the device of the invention; it refers to the accompanying drawings, in which the
  • Fig. 1 shows, for comparison, a preheating device of the prior art; the
  • Fig. 2 illustrates the principle of the preheating device according to the invention; and the
  • Fig. 3 shows in detail a preferred embodiment of a device of the invention.

Ces diverses figures constituent des représentations schématiques, dans lesquelles on s'est volontairement limité à ne montrer que les éléments nécessaires à la compréhension de l'invention. Pour la clarté de l'exposé, des éléments identiques ou assurant des fonctions identiques sont désignés par les mêmes repères numériques dans toutes les figures.These various figures constitute schematic representations, in which we have deliberately limited ourselves to showing only the elements necessary for understanding the invention. For the sake of clarity, identical elements or ensuring identical functions are designated by the same reference numerals in all the figures.

La Fig. 1 montre un dispositif de préchauffage représentatif de la technique antérieure du préchauffage d'une busette de coulée. On y à représenté un fragment d'un fond 1 de panier répartiteur de coulée continue de l'acier. Dans ce fragment de fond 1 est logée une busette de fond 2, qui est prolongée vers le bas par une busette extérieure 3. La busette de fond 2 présente, à l'entrée du trou de coulée 4, un siège arrondi 5 sur lequel vient s'appliquer l'extrémité inférieure profilée, ou nez 6, d'une quenouille 7 en matériau réfractaire. Un brûleur 8 est disposé sous la busette extérieure 3, en alignement avec celle-ci; la flamme 9 de ce brûleur peut se propager sur toute la longueur de la busette extérieure 3 et de la busette de fond 2, et atteindre le nez profilé 6 de la quenouille 7.Fig. 1 shows a preheating device representative of the prior art of preheating a pouring nozzle. There is shown a fragment of a bottom 1 of a basket for distributing continuous steel. In this bottom fragment 1 is housed a bottom nozzle 2, which is extended downwards by an external nozzle 3. The bottom nozzle 2 has, at the entrance of the tap hole 4, a rounded seat 5 on which comes apply the profiled lower end, or nose 6, of a stopper 7 of refractory material. A burner 8 is arranged under the external nozzle 3, in alignment with the latter; the flame 9 of this burner can propagate over the entire length of the outer nozzle 3 and of the bottom nozzle 2, and reach the profiled nose 6 of the stopper rod 7.

Une telle disposition du brûleur de préchauffage ne peut plus être utilisée avec une installation de coulée du type qui est représenté dans la Fig. 2. Ici, un dispositif de refroidissement de l'acier, désigné globalement par le repère 10, est placé entre le fond 1 et la busette extérieure 3. Ce dispositif comporte un dôme 11 en matière réfractaire, destiné à former un jet creux d'acier dans le dispositif 10. Ce dôme 11 empêcherait la flamme d'un brûleur inférieur de se propager jusqu'à la busette de fond 2 et au nez 6 de la quenouille 7.Such an arrangement of the preheating burner can no longer be used with a casting installation of the type which is shown in FIG. 2. Here, a steel cooling device, generally designated by the reference 10, is placed between the bottom 1 and the outer nozzle 3. This device comprises a dome 11 made of refractory material, intended to form a hollow jet of steel in the device 10. This dome 11 would prevent the flame of a lower burner from propagating to the bottom nozzle 2 and to the nose 6 of the stopper 7.

Dans son principe, le dispositif de préchauffage conforme à l'invention comporte une quenouille creuse 12, en matériau réfractaire, à l'intérieur de laquelle est placé un brûleur 13 dirigé de haut en bas, c'est-à-dire en direction du siège 5 et du trou de coulée 4 de la busette de fond 2. La flamme 14 peut alors atteindre la surface supérieure du dôme 11, ainsi que la busette 3, ce qui assure un écoulement fluide de l'acier vers le dispositif 10.In principle, the preheating device according to the invention comprises a hollow stopper rod 12, made of refractory material, inside which is placed a burner 13 directed from top to bottom, that is to say towards the seat 5 and the tap hole 4 of the bottom nozzle 2. The flame 14 can then reach the upper surface of the dome 11, as well as the nozzle 3, which ensures a fluid flow of the steel towards the device 10.

La Fig. 3 représente d'une manière plus détaillée un dispositif de préchauffage conforme à l'invention. Pour ne pas encombrer inutilement le dessin, on n'a pas reproduit le dispositif de refroidissement 10 et la busette extérieure 3, qui ne font pas partie de l'invention et qui sont d'ailleurs représentés dans la Fig. 2. Cet ensemble est rappelé par le dôme 11, qui est placé au débouché du trou de coulée 4 de la busette de fond 2.Fig. 3 shows in more detail a preheating device according to the invention. In order not to clutter the drawing unnecessarily, the cooling device 10 and the external nozzle 3, which are not part of the invention and which are moreover shown in FIG, have not been reproduced. 2. This assembly is recalled by the dome 11, which is placed at the outlet of the tap hole 4 of the bottom nozzle 2.

La quenouille 12 en matériau réfractaire est creuse; elle présente une chambre axiale 15, dans laquelle est disposé un brûleur 13 à prémélange. La chambre axiale 15 se prolonge au-delà de la tête 16 du brûleur en direction de l'extrémité inférieure de la quenouille; elle forme ainsi un volume libre 17, qui communique avec l'exté­rieur par un canal axial 18, de diamètre sensiblement inférieur à celui de ce volume libre 17. Le canal 18 débouche axialement dans le nez de la quenouille; il est également prévu des canaux latéraux 19 inclinés, qui débouchent d'une part dans le canal axial 18 et d'autre part dans la partie profilée 6 de la quenouille 12. Par ailleurs, le brûleur est alimenté en combustible et en comburant, de préférence gazeux, par deux conduites 21, 22 de faible diamètre. L'ensemble du brûleur, avec ses conduites d'alimentation, est de préférence réalisé en acier inoxydable.The stopper 12 of refractory material is hollow; it has an axial chamber 15, in which is disposed a premix burner 13. The axial chamber 15 extends beyond the head 16 of the burner in the direction of the lower end of the stopper; it thus forms a free volume 17, which communicates with the outside via an axial channel 18, of diameter substantially smaller than that of this free volume 17. The channel 18 opens axially in the nose of the stopper; inclined lateral channels 19 are also provided, which open on the one hand into the axial channel 18 and on the other hand into the profiled part 6 of the stopper rod 12. Furthermore, the burner is supplied with fuel and with oxidant, from preferably gas, by two pipes 21, 22 of small diameter. The entire burner, with its supply lines, is preferably made of stainless steel.

La tête 16 du brûleur 13 est centrée dans la chambre axiale 15 au moyen d'une bague 2u, qui assure également une séparation étanche entre le volume libre 17 et la partie supérieure ou amont de la chambre 15.The head 16 of the burner 13 is centered in the axial chamber 15 by means of a ring 2u, which also ensures a sealed separation between the free volume 17 and the upper or upstream part of the chamber 15.

Enfin, l'extrémité inférieure de la quenouille 12 peut être entourée d'un manchon 23, par exemple de forme tronconique, qui repose sur le fond 1 autour de la busette de fond 2.Finally, the lower end of the stopper 12 can be surrounded by a sleeve 23, for example of frustoconical shape, which rests on the bottom 1 around the bottom nozzle 2.

Le fonctionnement de ce dispositif se comprend aisément.The operation of this device is easily understood.

Les gaz combustibles et comburant parcourent à vitesse élevée les conduites 21, 22 et ils assurent ainsi le refroidissement de ces conduites et de la tête 16 du brûleur. Le mélange gazeux arrive à grande vitesse dans le volume libre 17 puis, par le canal axial 18 et les canaux latéraux 19, la flamme 14 sort de l'extrémité infé­rieure de la quenouille 12 en direction de la busette de fond 2. La flamme axiale pénètre dans le trou de coulée 4 et se propage jus­qu'au dôme dont elle chauffe la surface supérieure. Les flammes latérales échauffent le siège 5 de la busette de fond 2.The combustible and oxidizing gases pass through the pipes 21, 22 at high speed and thus ensure the cooling of these pipes and of the burner head 16. The gas mixture arrives at high speed in the free volume 17 then, through the axial channel 18 and the lateral channels 19, the flame 14 leaves the lower end of the stopper 12 in the direction of the bottom nozzle 2. The axial flame penetrates into the tap hole 4 and spreads to the dome, the upper surface of which it heats. The side flames heat the seat 5 of the bottom nozzle 2.

A cet égard, les canaux latéraux 19 sont inclinés sur le canal axial 18 d'un angle inférieur à 90°, et de préférence inférieur à 60°. Cet angle est choisi, selon le profil du siège 5 et de l'arrondi 6, de telle façon que les canaux latéraux 19 soient dirigés vers le siège 5 pendant la période de préchauffage de la busette et qu'ils ne soient pas obstrués par l'acier lorsque la quenouille est appliquée sur le siège 5.In this regard, the lateral channels 19 are inclined on the axial channel 18 at an angle less than 90 °, and preferably less than 60 °. This angle is chosen, according to the profile of the seat 5 and of the roundness 6, in such a way that the lateral channels 19 are directed towards the seat 5 during the period of preheating of the nozzle and that they are not obstructed by the steel when the stopper rod is applied to the seat 5.

Le manchon 23 est de préférence constitué de fibre céramique de faible densité. Il permet d'éviter le soufflage de la flamme 14 par les remous de gaz ou d'air qui peuvent se produire dans le panier répartiteur. Il assure également le maintien d'une température élevée autour du siège 5 en réduisant les pertes de chaleur. La hauteur du manchon 23 doit être suffisante pour garantir la protection recherchée.The sleeve 23 is preferably made of low density ceramic fiber. It avoids the blowing of the flame 14 by gas or air eddies which can occur in the distributor basket. It also maintains a high temperature around the seat 5 by reducing heat loss. The height of the sleeve 23 must be sufficient to guarantee the desired protection.

L'efficacité du préchauffage peut également être influencée par la position relative du brûleur 16 et du nez 6 de la quenouille par rapport au siège 5 de la busette à préchauffer. Cette position peut être définie par la hauteur H du brûleur 16 et/ou h du nez 6 au­dessus du fond 1 du panier; cette hauteur dépend notamment de la géométrie de la busette 2 (diamètre, rayon de courbure du siège).The efficiency of preheating can also be influenced by the relative position of the burner 16 and the nose 6 of the stopper rod relative to the seat 5 of the nozzle to be preheated. This position can be defined by the height H of the burner 16 and / or h of the nose 6 above the bottom 1 of the basket; this height depends in particular on the geometry of the nozzle 2 (diameter, radius of curvature of the seat).

Il est cependant apparu que la hauteur H devait être comprise de préférence entre 300 mm et 600 mm, et que la hauteur h devait de préférence être inférieure à et 50 mm.However, it appeared that the height H should be understood to be preferably between 300 mm and 600 mm, and that the height h should preferably be less than and 50 mm.

A titre d'exemple, on a préchauffé une busette de fond en alumine graphitée, et un dôme de distribution, disposé comme le montre la Fig.3. On a utilisé une flamme fournie par la combustion de 3 m³ N/h de gaz avec 11 m³ N/h d'air. L'excès de gaz avait pour but d'accroître la stabilité de la flamme et d'éviter la décarburation de la busette en alumine graphitée. La hauteur h valait 20 mm et la hauteur H était de 470 mm; le manchon avait une hauteur de 300 mm. Après une durée de préchauffage d'environ 2 h 30 min., le dôme et la busette présentaient une température de l'ordre de 1200°C, nettement suffisante pour commencer la coulée de l'acier sans risque de figeage.For example, a bottom nozzle in graphite alumina was preheated, and a distribution dome, arranged as shown in Fig.3. A flame supplied by the combustion of 3 m³ N / h of gas with 11 m³ N / h of air was used. The purpose of the excess gas was to increase the stability of the flame and to avoid decarburization of the graphite alumina nozzle. The height h was 20 mm and the height H was 470 mm; the sleeve was 300 mm high. After a preheating time of approximately 2 h 30 min., The dome and the nozzle had a temperature of the order of 1200 ° C., clearly sufficient to start casting the steel without risk of freezing.

Le dispositif de l'invention permet de chauffer avec la même efficacité une zone relativement longue allant du siège 5 au dôme 11. Il assure une puissance de chauffage élevée, tout en garantissant une bonne résistance à la température de la tête du brûleur. Il ne pose aucun problème d'encombrement ou de mise en place.The device of the invention allows a relatively long area to be heated with the same efficiency going from the seat 5 to the dome 11. It provides a high heating power, while guaranteeing good resistance to the temperature of the burner head. There is no problem of space or installation.

L'invention n'est bien entendu pas limitée à l'exemple de réalisation qui vient d'être décrit et illustré. Elle englobe également diverses modifications qu'un homme de métier pourrait y apporter, par exemple en utilisant un tube réfractaire qui ne soit pas la quenouille de fermeture du trou de coulée. Par ailleurs, le dispositif de l'invention peut être utilisé pour le préchauffage de busettes de coulée de type usuel ne comportant pas de dôme de répartition du métal. Enfin, l'emploi du dispositif de l'invention n'est pas limité à la coulée continue.The invention is of course not limited to the embodiment which has just been described and illustrated. It also includes various modifications that a person skilled in the art could make to it, for example by using a refractory tube which is not the stopper stopper stopper. Furthermore, the device of the invention can be used for the preheating of conventional type casting nozzles having no metal distribution dome. Finally, the use of the device of the invention is not limited to continuous casting.

Claims (10)

1. Dispositif de préchauffage d'une busette (2) de coulée d'un métal en fusion, ladite busette étant, au moins en partie, disposée dans le garnissage réfractaire du fond (1) d'un récipient métallurgique, caractérisé en ce qu'il comporte au moins un brûleur (13) qui est disposé à l'intérieur dudit récipient métallurgique et qui est orienté vers la section d'entrée de ladite busette de coulée (2), et en ce que ledit brûleur est logé dans un tube (12) de protection contre le métal en fusion.1. Device for preheating a nozzle (2) for casting a molten metal, said nozzle being, at least in part, disposed in the refractory lining of the bottom (1) of a metallurgical container, characterized in that '' it comprises at least one burner (13) which is disposed inside said metallurgical container and which is oriented towards the inlet section of said pouring nozzle (2), and in that said burner is housed in a tube (12) protection against molten metal. 2. Dispositif suivant la revendication 1, caractérisé en ce que ledit tube de protection est une quenouille (12) de fermeture de ladite busette de coulée, en ce que ledit brûleur (13) est disposé dans une chambre (15) ménagée à l'intérieur de ladite quenouille et en ce que l'extrémité inférieure de ladite quenouille (]2) est percée d'au moins un canal (18) communiquant avec ladite chambre (15).2. Device according to claim 1, characterized in that said protective tube is a stopper (12) for closing said pouring nozzle, in that said burner (13) is arranged in a chamber (15) provided in the inside of said stopper and in that the lower end of said stopper (] 2) is pierced with at least one channel (18) communicating with said chamber (15). 3. Dispositif suivant la revendication 2, caractérisé en ce que la chambre (15) s'étend suivant la direction longitudinale de la quenouille coaxialement à celle-ci, et en ce que le brûleur (13) occupe une partie supérieure de la chambre (15), celle-ci présen­tant ainsi un volume libre (17) dans la région de l'extrémité inférieure de la quenouille (12).3. Device according to claim 2, characterized in that the chamber (15) extends in the longitudinal direction of the stopper coaxially thereto, and in that the burner (13) occupies an upper part of the chamber ( 15), the latter thus having a free volume (17) in the region of the lower end of the stopper rod (12). 4. Dispositif suivant la revendication 3, caractérisé en ce que dans le volume libre (17) débouchent d'une part le brûleur (13) et d'autre part le canal (18) percé dans l'extrémité inférieure de la quenouille.4. Device according to claim 3, characterized in that in the free volume (17) open on the one hand the burner (13) and on the other hand the channel (18) pierced in the lower end of the stopper rod. 5. Dispositif suivant l'une ou l'autre des revendications 2 à 4, caractérisé en ce que le brûleur (13) est pourvu, dans la région de son extrémité de sortie, de moyens de centrage et/ou d'étanchéité (20) dans ladite chambre (15).5. Device according to either of Claims 2 to 4, characterized in that the burner (13) is provided, in the region of its outlet end, with centering and / or sealing means (20 ) in said chamber (15). 6. Dispositif suivant l'une ou l'autre des revendications 2 à 5, caractérisé en ce que ledit canal (18) comporte un tronçon coaxial à la busette (12) et présentant un diamètre inférieur à celui de la chambre (15).6. Device according to either of claims 2 to 5, characterized in that said channel (18) comprises a section coaxial with the nozzle (12) and having a diameter less than that of the chamber (15). 7. Dispositif suivant l'une ou l'autre des revendications 2 à 6, caractérisé en ce qu'il est prévu, à l'extrémité inférieure de la quenouille (12), plusieurs canaux de sortie latéraux (19) qui entourent ledit canal axial et qui débouchent dans celui-ci sous des angles appropriés.7. Device according to either of claims 2 to 6, characterized in that there is provided, at the lower end of the stopper (12), several lateral outlet channels (19) which surround said channel axial and which open into it at suitable angles. 8. Dispositif suivant l'une ou l'autre des revendications 1 à 7, caractérisé en ce qu'il est prévu un manchon (23) autour de l'extrémité inférieure du tube de protection, respectivement de la quenouille.8. Device according to either of Claims 1 to 7, characterized in that a sleeve (23) is provided around the lower end of the protective tube, respectively of the stopper rod. 9. Dispositif suivant l'une ou l'autre des revendications 1 à 8, caractérisé en ce que la distance H entre le fond (1) du récipient métallurgique et la sortie du brûleur (13) est comprise entre 300 mm et 600 mm.9. Device according to either of claims 1 to 8, characterized in that the distance H between the bottom (1) of the metallurgical vessel and the outlet of the burner (13) is between 300 mm and 600 mm. 10. Dispositif suivant l'une ou l'autre des revendications 1 à 9, caractérisé en ce que la distance h entre le fond (1) du récipient métallurgique et l'extrémité inférieure du barreau, respectivement de la quenouille (12), est inférieure à 50 mm.10. Device according to either of claims 1 to 9, characterized in that the distance h between the bottom (1) of the metallurgical container and the lower end of the rod, respectively of the stopper rod (12), is less than 50 mm.
EP90870094A 1989-06-27 1990-06-19 Preheating device for a molten metal casting nozzle and metal casting installation comprising such device Expired - Lifetime EP0406208B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE8900702A BE1004282A6 (en) 1989-06-27 1989-06-27 Warming device of casting nozzle for metal fusion and casting plant of metal equipped with this device.
BE8900702 1989-06-27

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EP0406208A1 true EP0406208A1 (en) 1991-01-02
EP0406208B1 EP0406208B1 (en) 1994-08-10

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EP90870094A Expired - Lifetime EP0406208B1 (en) 1989-06-27 1990-06-19 Preheating device for a molten metal casting nozzle and metal casting installation comprising such device

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AT (1) ATE109700T1 (en)
BE (1) BE1004282A6 (en)
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0495764A1 (en) * 1991-01-16 1992-07-22 CENTRE DE RECHERCHES METALLURGIQUES CENTRUM VOOR RESEARCH IN DE METALLURGIE Association sans but lucratif Preheating device for a molten metal casting nozzle
EP0562997A1 (en) * 1992-03-25 1993-09-29 Olifan-Vibracim S.A. Heat insulating device
CN103934445A (en) * 2014-04-09 2014-07-23 张家港联峰钢铁研究所有限公司 Cooling device for submersed nozzle

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2475777A (en) * 1945-09-24 1949-07-12 Brown Edward Heater for nozzle holes in steel ladles
WO1986002435A1 (en) * 1984-10-16 1986-04-24 Kortec Ag Closure apparatus for a tap hole
WO1988006068A1 (en) * 1987-02-20 1988-08-25 Daussan Et Compagnie Installation for pouring liquid metal, and process for its implementation

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2475777A (en) * 1945-09-24 1949-07-12 Brown Edward Heater for nozzle holes in steel ladles
WO1986002435A1 (en) * 1984-10-16 1986-04-24 Kortec Ag Closure apparatus for a tap hole
WO1988006068A1 (en) * 1987-02-20 1988-08-25 Daussan Et Compagnie Installation for pouring liquid metal, and process for its implementation

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0495764A1 (en) * 1991-01-16 1992-07-22 CENTRE DE RECHERCHES METALLURGIQUES CENTRUM VOOR RESEARCH IN DE METALLURGIE Association sans but lucratif Preheating device for a molten metal casting nozzle
EP0562997A1 (en) * 1992-03-25 1993-09-29 Olifan-Vibracim S.A. Heat insulating device
FR2689208A1 (en) * 1992-03-25 1993-10-01 Olifan Vibracim Sa Thermal insulation device.
CN103934445A (en) * 2014-04-09 2014-07-23 张家港联峰钢铁研究所有限公司 Cooling device for submersed nozzle

Also Published As

Publication number Publication date
DE69011436T2 (en) 1995-05-24
ATE109700T1 (en) 1994-08-15
BE1004282A6 (en) 1992-10-27
DE69011436D1 (en) 1994-09-15
EP0406208B1 (en) 1994-08-10

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