EP0213042B1 - Equipment for protecting a liquid-metal jet against oxidation and/or nitriding - Google Patents

Equipment for protecting a liquid-metal jet against oxidation and/or nitriding Download PDF

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Publication number
EP0213042B1
EP0213042B1 EP86401792A EP86401792A EP0213042B1 EP 0213042 B1 EP0213042 B1 EP 0213042B1 EP 86401792 A EP86401792 A EP 86401792A EP 86401792 A EP86401792 A EP 86401792A EP 0213042 B1 EP0213042 B1 EP 0213042B1
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EP
European Patent Office
Prior art keywords
shell
shells
distributor
casting
jet
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.)
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EP86401792A
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German (de)
French (fr)
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EP0213042A2 (en
EP0213042A3 (en
Inventor
Jean Foulard
Jacques Nicolas
Jean-François Mignot
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LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Application filed by LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority to AT86401792T priority Critical patent/ATE56642T1/en
Publication of EP0213042A2 publication Critical patent/EP0213042A2/en
Publication of EP0213042A3 publication Critical patent/EP0213042A3/en
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Publication of EP0213042B1 publication Critical patent/EP0213042B1/en
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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
    • B22D37/00—Controlling or regulating the pouring of molten metal from a casting melt-holding vessel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/106—Shielding the molten jet

Definitions

  • the present invention relates to the protection of a jet of liquid metal flowing from a pocket outlet or a distributor in a mold, according to which the casting jet is surrounded, over at least part of its height. , a sleeve into which a liquid metal protection gas is injected, so as to limit the contact of the latter with the ambient air between the outlet orifice and the ingot mold.
  • Devices have already been proposed for ensuring this protection, which are of the type comprising two substantially semi-cylindrical half-shells articulated around a vertical axis and each having at their upper end a sheath supplying protective gas.
  • a device of this kind is described in document DE-A-2,517,834 which provides a wafer-shaped sleeve located a short distance from the bottom of the distributor, the gas escaping both through the annular walls of the upper bottom and lower and through a sleeve obviously surrounding the jet over a small part of its height.
  • Such a device is not capable of providing adequate protection in the lower part of the casting jet.
  • the present invention aims to provide gaseous protection over the entire height of the jet of liquid metal, without having to extend to the mold, which is detrimental to the visual control of the casting operation and this objective is achieved.
  • the device in that on the one hand the device is applied in a sealed manner against the lower wall of the distributor, and on the other hand the axial length of the shells is chosen so that, when the device is applied against the bottom of the distributor, leave a clearance of axial length less than 100 mm between the lower end of the shell and the mold.
  • this axial length between the lower end of the shell and the ingot mold is less than 80 mm.
  • the axial length between the lower end of the shell and the ingot mold is less than 80 mm.
  • the invention also relates to an advantageous embodiment according to which the junction planes of the two half-shells partially overlap so as to improve the tightness of the shell.
  • a circular ferrule is provided which is integral with the tundish and intended to improve the gas tightness.
  • gases used to protect the casting jet against oxidation and / or nitriding are those usually used in such cases by those skilled in the art, such as nitrogen, argon, carbon dioxide, etc. ... used alone and / or in mixtures.
  • Figure 1 is a schematic sectional view of an embodiment of the device according to the invention as well as certain variants.
  • the protection device comprises a shell 1 consisting of two complementary half-shells 1A, 1B, as well as means for injecting protective gas, these means essentially consisting of a channel 8 of annular shape placed at the top of the shell 1, this channel 8 being provided with perforations 9 allowing the passage of gas from the supply lines 7A and 7B, respectively connected to the two annular half-channels 8A and 8B constituting the channel 8 and respectively integral with the two half shells 1A and 1B.
  • the device further comprises means for articulation of the half-shells, not shown in the figure. (the diameter, the position, the number of perforations will be determined experimentally by a person skilled in the art, by simple routine experiments, depending on the result that one wishes to obtain and the flow rate of inert gas).
  • the distributor of which only the bottom 3 can be seen in the figure is provided with a ferrule 5 of shape complementary to the external shape of the channel 8, that is to say circular in the present case.
  • the annular channel 8 On its upper face, the annular channel 8 has a circular groove 48 in which is housed a seal 4 ensuring the seal between the distributor and the device according to the invention.
  • the two half-shells 1A and 1B partially overlap along the joint line 6, ensuring a seal thanks to a structure in the form of a baffle.
  • the inner wall 66 of the half-shell 1B is fixed radially to the latter, with a recess 72.
  • the internal wall 65 is fixed radially to the half-shell 1A, at the end of the latter. It also includes a recess 73, complementary to the recess 72, which thus form a baffle 67, 68 and 69 for the gas coming from inside the shell and which would escape towards the outside. With such a pressure drop, the gas, introduced in the form of a laminar flow into the shell through the openings 9, cannot practically escape through the side seal 6.
  • the reference 10A represents two alternative embodiments of the aerodynamic means according to the invention placed at the lower end of the shell 1.
  • the internal wall of the half-shell 1A is chamfered at approximately 45 °, on the one hand, a flange 52 being fixed at the end, on the outer wall of the shell 1, while a flaring 352 of internal diameter D 4 extends the shells 1A, 1B, of internal diameter D 2 at their lower part.
  • the reference 10B shows an alternative embodiment of the walls of the shell 1 making it possible to further improve the gas protection.
  • the half-shells such as 1B, are surrounded, substantially from the base of the annular channel 8 at the lower end of the half-shell, by a sheath 70, arranged coaxially with the half-shells, so as to provide a space 71 which communicates with the annular gas supply channel 8 or gas distribution chamber.
  • This gas supply could be different if we wanted to create a gas duct of a different nature).
  • This sheath 70 preferably comprises an aerodynamic collar 52 at its base.
  • the protection device being designed in particular for continuous casting in molds of small dimensions, it is not possible, in this case to introduce the lower end of the shell into the metal taking into account the respective dimensions of the jet, the shell and the opening of the mold. This is why, there is a clearance between the lower part of the shell and the pouring opening, this clearance allowing moreover the operation of the device during casting, if this proves necessary.
  • the inerting shell 1 centered on the pouring jet 2 is pressed against the bottom of the distributor 3, in an almost leaktight manner, using a seal 4 made of refractory or metalloplastic fibrous product, and / or thanks to the circular ferrule 5.
  • the two half-shells 1A and 1B are pressed one against the other and sealing between them is ensured by the baffle-shaped seal 6 over the entire length of the device.
  • Two gas inlets 7A and 7B, of sufficient diameter to guarantee a very low speed of supply of protective gas lead into the distribution chambers 8A and 8B.
  • the gas then flows in laminar mode through the holes 9 and sheaths the metal jet to the lower part of the shell.
  • aerodynamic means are used.
  • the deflector moreover, results in better coverage of the upper part of the ingot mold thus ensuring greater efficiency of the inerting.
  • the dimensions and shape of the deflector can be adapted to the different formats of the molds.
  • a notch can be formed in a corner of the mold.
  • FIG. 2 is a perspective sketch showing the half-shells in the open position around the casting jet shown diagrammatically by the reference 102.
  • the protection device comprises two complementary half-shells 101A and 101B, surrounded at their upper part by complementary distribution chambers 108A and 108B of semi-annular shape, connected respectively to a gas supply not shown in the figure, and openings pierced 109 regularly distributed over the surface of the corresponding half-shells 101A and 101B, so as to allow the passage of the shielding gas between the half-shells 101A and 101 Swiss pour casting 102.
  • the distribution chambers 108A and 108B are closed at their ends.
  • Each half-shell has at its lower part a half-flange 150A and 150B, complementary to each other.
  • the junction between the half-shells on the one hand and the half-flanges on the other is done using the junction planes 157 and 158 extending respectively from the base of the distribution chambers 108A and 108B to half-flanges 150A and 150B.
  • These junction planes have the shape of a trapezoid-rectangle if the shell is cylindrical. (But this shell can also have the shape of a truncated cone).
  • Junction planes 157 and 158 are so thick that they overlap the joint plane two half-shells thus forming a baffle as described in FIG. 1.
  • the half-flange 150B is slightly longer than the half-circumference of the half-shell 101B at its base. Conversely, the half-collar 150A is slightly shorter than 101A. Thus, the half-flange 150B projects slightly beyond the junction planes 157 and 158, which makes it possible to extend the chicane joint at the level of the half-flanges.
  • the distribution chamber has two annular grooves 104 and 1040 to accommodate a seal with the base of the distributor.
  • Figure 3 shows two sectional views of the device of Figure 2, in the closed position.
  • the two half-shells 101A and 101B bear substantially one on the other at 160, 163, 260, 263, and delimit baffles 161, 162 and 261, 262 respectively.
  • Figure 3B which is a section along the axis AA of Figure 3A has the same references as Figure 3A.
  • FIG. 4A shows diagrammatically a first alternative embodiment of the assembly of the device according to the invention, provided with its control means.
  • the shell 1 comprises a hinge 31 allowing the opening and closing of the half-shells around the pouring jet (not shown) in the opening 30 of the oscillating ingot mold.
  • the shell 1 is connected via 31 to a first arm 32 which pivots horizontally on a second arm 34 around the articulation 33. (movement 1 the vertical arm 34 slides from bottom to top (movement 3 under the action of the jack 35, allowing the device 1 to be pressed onto the distributor (not shown).
  • 35 can be fixed to the casting table.
  • the jack 35 is fixed to the flow distributor 39 and is supplied with compressed air (for maneuvers) via 37 and inerting gas (argon and / or zote, and / or carbon dioxide) via 36.
  • the protection device is fixed on a support forming a protective gas pipe and comprising a movable part allowing the opening of the shells, this can be fixed on the wall of the pocket or of the distributor as well as on any support integral with its cradle, for such purpose to be able to operate the device in a manner integral with the pocket or the distributor; in some cases, it is possible to fix this assembly on the casting table.
  • the support arm is fixed on a journal allowing the exhaust of the jet protection device by a rotation of the latter.
  • a jack resting on the end of the arm applies the half-shell device to the bottom of the distributor, exerting a docking force of approximately 50 deca Newton, to ensure sealing as soon as the actuator goes into action to lower the device, the opening articulation is automatically biased by a spring which has been stretched when closing using a pushing arm held in place by a spring-controlled finger device.
  • FIG. 5 represents a preferred embodiment of the control means of the device according to the invention.
  • the two half-shells are shown diagrammatically by the references 401A and 401B in the open position corresponding to the position of the control means shown in the figure.
  • a main part consisting of a support arm 435, the end of which is bent on the side of the half-shell 401 B which is fixed to it by a ball joint 462.
  • the latter is located substantially at the end of the part right of arm 435.
  • the other half-shell 401A is secured, by the ball joint 461 to a plurality of articulated arms 489, the end 431 of which is bent around the half-shell 401A, connected to the arm 426 by the articulation 428, itself even connected to the arm 423, 421 ending with a control handle 420.
  • the arm 423, 421 slides in a cylindrical guide 422 as well as in a cylindrical guide 424.
  • the guides 422 and 424 are integral with the arm 423, itself fixed by its right end in the figure, to a carriage 450 sliding on a rail 451 in the direction of the arrow F.
  • An operating handle 437 is provided for controlling the rotation of the arm 435 about the axis 0 perpendicular to the plane of the figure.
  • the axis 436 allows rotation of the arm 435, so as to generate the movement of the shells so as to make them cross the plane of the figure.
  • the control lever 420 is pushed to the left in the direction of 422, causing the half-shells to close in the position shown diagrammatically in dotted lines. (a locking system keeps it in this position, unlockable manually).
  • the shell is placed under the distributor, for example using a jack which causes the arm 435 to rotate about the axis 436.
  • the half-shells initially, under the plane of the figure, have their upper side which passes over above the plane of the figure.
  • the reference 401AB represents the two closed half-shells brought into this position after rotation of the arm 435 around the axis 0 (perpendicular to the plane of the figure), followed by a closing of the half-shells using 420 ( then rotation of 435 around axis 436).
  • a protective shell (or sleeve) with an internal diameter of 80 mm is used at its base without collar.
  • the nitrogen flow rate is 60 Nm 3 / h, the specific consumption being approximately 5 Nm 3 / tonne.
  • the lower part of the shell is placed at an average distance from the oscillating ingot mold equal to 50 mm.
  • the speed of ejection of the shell protection gas at the periphery of its lower part is approximately 1.5 m / s, and approximately 3.5 m / s along the jet.
  • the operation is carried out under the same conditions as above with a flow rate of 30 Nm 3 / h.
  • the gas exit velocity at the periphery of the lower part of the shell is about 0.7 m / s, 1.7 m / s near the jet. Results are obtained slightly lower than the previous ones (the oxygen concentration curve equal to 1% between the lower part of the shell and the opening of the ingot mold is slightly closer to the casting jet than previously, but the latter remains perfectly protected).
  • the oxygen contents measured in the ingot mold generally remain above 1%.
  • the oscillations of the ingot mold induce a dilution such that it is generally not possible to obtain an oxygen content of less than 1%, at near the jet, in the mold.
  • the operation is carried out under the same conditions as above with a flow rate of 90 Nm 3 / g.
  • the gas exit velocity is 2.5 m / s and 5.5 m / s respectively.
  • Examples 1, 2 and 3 are repeated by adding a 6 mm flange around the shell with a chamfer at about 45 °, at its lower part, parallel to the opening of the mold.
  • the constant oxygen concentration curves around the casting jet are significantly more distant from the jet than the corresponding curves, in the absence of a collar, which means a slight improvement in the results.
  • the use of a flange can therefore be useful when seeking to further lower the oxygen concentrations near the jet.
  • Examples 1, 2 and 3 are repeated by forming a flare in the lower part of the shell, flare increasing the lower diameter by 12 mm (internal diameter at the lower part of the shell by approximately 92 mm).
  • a flare preferably of circular section, of height substantially equal to the increase in the radius of the shell. In the present case, this height is therefore substantially equal to 6 mm.

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  • Mechanical Engineering (AREA)
  • Engineering & Computer Science (AREA)
  • Continuous Casting (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Forging (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Disintegrating Or Milling (AREA)
  • Jet Pumps And Other Pumps (AREA)
  • Gas Separation By Absorption (AREA)
  • Chemically Coating (AREA)
  • Catching Or Destruction (AREA)

Abstract

Process for protecting against oxidation and/or nitridation of a liquid metal stream flowing from the outlet orifice of a ladle or a distribution vessel, comprising surrounding the pouring stream with a tube substantially throughout the height of the stream and injecting a protective gas at least around the pouring stream so as to minimize the contact of the molten metal with the ambient air and avoid the dilution of the protective gas and the aspiration of ambient air. A device for carrying out the process includes two complementary semi-shells for surrounding the pouring stream and a hinge articulating the semi-shells for opening and closing the latter.

Description

La présente invention concerne la protection d'un jet de métal liquide s'écoulant d'un orifice de sortie de poche ou d'un répartiteur dans une lingotière, selon laquelle on entoure le jet de coulée, sur au moins une partie de sa hauteur, d'un manchon dans lequel on injecte un gaz de protection du métal liquide, de manière à limiter le contact de celui-ci avec l'air ambiant entre l'orifice de sortie et la lingotière.The present invention relates to the protection of a jet of liquid metal flowing from a pocket outlet or a distributor in a mold, according to which the casting jet is surrounded, over at least part of its height. , a sleeve into which a liquid metal protection gas is injected, so as to limit the contact of the latter with the ambient air between the outlet orifice and the ingot mold.

On a déjà proposé des dispositifs destinés à assurer cette protection, qui sont du genre comprenant deux demi-coquilles substantiellement semi-cylindriques articulées autour d'un axe vertical et comportant à leur extrémité supérieure chacune une gaine alimentatrice en gaz de protection. Un dispositif de ce genre est décrit dans le document DE-A-2.517.834 qui prévoit un manchon en forme de galette situé à faible distance du fond du répartiteur, le gaz s'échappant à la fois au travers des parois annulaires de fond supérieure et inférieure et au travers d'un manchon entourant le jet manifestement sur une faible partie de sa hauteur. Un tel dispositif n'est pas apte à assurer une protection convenable dans la partie basse du jet de coulée. Un autre dispositif de ce type est décrit dans l'U.S.-A-3.439.735 où le manchon s'étend à la fois à faible distance du fond du répartiteur et d'un moule inférieur, en sorte que le gaz de protection introduit en position supérieure a tendance à s'échapper vers le haut, ce qui est encore accentué par une jupe inférieure évasée qui vient en contact avec le moule.Devices have already been proposed for ensuring this protection, which are of the type comprising two substantially semi-cylindrical half-shells articulated around a vertical axis and each having at their upper end a sheath supplying protective gas. A device of this kind is described in document DE-A-2,517,834 which provides a wafer-shaped sleeve located a short distance from the bottom of the distributor, the gas escaping both through the annular walls of the upper bottom and lower and through a sleeve obviously surrounding the jet over a small part of its height. Such a device is not capable of providing adequate protection in the lower part of the casting jet. Another device of this type is described in US-A-3,439,735 where the sleeve extends both a short distance from the bottom of the distributor and from a lower mold, so that the protective gas introduced in upper position tends to escape upwards, which is further accentuated by a flared lower skirt which comes into contact with the mold.

La présente invention vise à assurer une protection gazeuse sur toute la hauteur du jet de métal liquide, sans pour autant devoir s'étendre jusqu'à la lingotière, ce qui est préjudiciable au contrôle visuel de l'opération de coulée et cet objectif est atteint selon l'invention en ce que d'une part le dispositif est appliqué de façon étanche contre la paroi inférieure du répartiteur, et d'autre part la longueur axiale des coquilles est choisie de façon à, lorsque le dispositif est appliqué contre le fond du répartiteur, laisser subsister un dégagement de longueur axiale inférieure à 100 mm entre l'extrémité inférieure de la coquille et la lingotière. De préférence, cette longueur axiale entre l'extrémité inférieure de la coquille et la lingotière est inférieure à 80 mm. On a pu constater que cet agencement permettait à coup sûr d'isoler le jet sur toute la hauteur, en faisant en sorte que tout le gaz injecté soit dirigé vers le bas, sans aspiration d'air au niveau supérieur, alors que la distance axiale non entourée par le manchon est suffisamment faible pour que le rideau de gaz de protection issu du manchon assure la protection requise, tout en laissant un dégagement suffisant pour l'inspection visuelle du pied de coulée.The present invention aims to provide gaseous protection over the entire height of the jet of liquid metal, without having to extend to the mold, which is detrimental to the visual control of the casting operation and this objective is achieved. according to the invention in that on the one hand the device is applied in a sealed manner against the lower wall of the distributor, and on the other hand the axial length of the shells is chosen so that, when the device is applied against the bottom of the distributor, leave a clearance of axial length less than 100 mm between the lower end of the shell and the mold. Preferably, this axial length between the lower end of the shell and the ingot mold is less than 80 mm. It has been observed that this arrangement certainly makes it possible to isolate the jet over the entire height, by ensuring that all of the injected gas is directed downwards, without air suction at the upper level, while the axial distance not surrounded by the sleeve is weak enough for the curtain of shielding gas from the sleeve to provide the required protection, while leaving sufficient clearance for the visual inspection of the casting foot.

Selon une forme préférentielle de l'invention, la longueur axiale entre l'extrémité inférieure de la coquille et la lingotière est inférieure à 80 mm.According to a preferred form of the invention, the axial length between the lower end of the shell and the ingot mold is less than 80 mm.

L'invention concerne également une forme de réalisation avantageuse selon laquelle les plans de jonction des deux demi-coquilles se recouvrent partiellement de manière à améliorer l'étanchéité de la coquille. Dans un agencement où le dispositif comporte à sa partie supérieure un joint d'étanchéité entre coquille et répartiteur de coulée, on prévoit une virole circulaire solidaire du répartiteur et destinée à améliorer l'étanchéité du gaz.The invention also relates to an advantageous embodiment according to which the junction planes of the two half-shells partially overlap so as to improve the tightness of the shell. In an arrangement where the device comprises at its upper part a seal between the shell and the tundish, a circular ferrule is provided which is integral with the tundish and intended to improve the gas tightness.

Les gaz utilisés pour la protection du jet de coulée contre l'oxydation et/ou la nitruration sont ceux habituellement utilisés dans de tels cas par l'homme de métier, tels que l'azote, l'argon, l'anhydride carbonique, etc... utilisés seuls et/ou en mélanges.The gases used to protect the casting jet against oxidation and / or nitriding are those usually used in such cases by those skilled in the art, such as nitrogen, argon, carbon dioxide, etc. ... used alone and / or in mixtures.

L'invention sera mieux comprise à l'aide des exemples de réalisation suivants, donnés à titre non limitatif, conjointement avec les figures qui représentent:

  • - la figure 1 est une vue en coupe verticale schématique d'un dispositif de protection contre l'oxydation d'un jet de métal liquide suivant l'invention;
  • - la figure 2, une vue d'un exemple de réalisation selon l'invention, les deux demi-coquilles étant en position ouverte;
  • - les figures 3A et 3B, des vues en coupe de l'exemple de réalisation de la figure 2, les demi-coquilles étant fermées;
  • - les figures 4A et 4B, une vue schématique de variantes de réalisation des moyens de commandes de l'ouverture et de la fermeture des demi-coquilles;
  • - la figure 5, une vue détaillée de moyens de commande du mouvement des demi-coquilles, selon un mode préféré de réalisation.
The invention will be better understood with the aid of the following embodiments, given without limitation, together with the figures which represent:
  • - Figure 1 is a schematic vertical sectional view of a device for protection against oxidation of a jet of liquid metal according to the invention;
  • - Figure 2, a view of an exemplary embodiment according to the invention, the two half-shells being in the open position;
  • - Figures 3A and 3B, sectional views of the embodiment of Figure 2, the half-shells being closed;
  • - Figures 4A and 4B, a schematic view of alternative embodiments of the means for controlling the opening and closing of the half-shells;
  • - Figure 5, a detailed view of means for controlling the movement of the half-shells, according to a preferred embodiment.

La figure 1 est une vue en coupe schématique d'un exemple de réalisation du dispositif selon l'invention ainsi que de certaines variantes.Figure 1 is a schematic sectional view of an embodiment of the device according to the invention as well as certain variants.

Le dispositif de protection selon l'invention comporte une coquille 1 constituée de deux demi-coquilles 1A, 1B complémentaires, ainsi que des moyens pour l'injection de gaz protecteur, ces moyens étant essentiellement constitués d'un canal 8 de forme annulaire placé au sommet de la coquille 1, ce canal 8 étant muni de perforations 9 permettant le passage du gaz issu des conduites d'alimentation 7A et 7B, respectivement reliées aux deux demi canaux annulaires 8A et 8B constituant le canal 8 et respectivement solidaires des deux demi-coquilles 1A et 1B. Le dispositif comporte en outre des moyens d'articulation des demi-coquilles, non représentés sur la figure. (le diamètre, la position, le nombre des perforations seront déterminés expérimentalement par l'homme de métier, par de simples expériences de routine, en fonction du résultat que l'on veut obtenir et du débit de gaz inerte).The protection device according to the invention comprises a shell 1 consisting of two complementary half-shells 1A, 1B, as well as means for injecting protective gas, these means essentially consisting of a channel 8 of annular shape placed at the top of the shell 1, this channel 8 being provided with perforations 9 allowing the passage of gas from the supply lines 7A and 7B, respectively connected to the two annular half-channels 8A and 8B constituting the channel 8 and respectively integral with the two half shells 1A and 1B. The device further comprises means for articulation of the half-shells, not shown in the figure. (the diameter, the position, the number of perforations will be determined experimentally by a person skilled in the art, by simple routine experiments, depending on the result that one wishes to obtain and the flow rate of inert gas).

Le répartiteur dont on ne voit que le fond 3 sur la figure est muni d'une virole 5 de forme complémentaire à la forme extérieure du canal 8, c'est-à-dire circulaire dans le cas présent. Sur sa face supérieure, le canal annulaire 8 comporte une gorge circulaire 48 dans laquelle est logé un joint 4 assurant l'étanchéité entre le répartiteur et le dispositif selon l'invention.The distributor of which only the bottom 3 can be seen in the figure is provided with a ferrule 5 of shape complementary to the external shape of the channel 8, that is to say circular in the present case. On its upper face, the annular channel 8 has a circular groove 48 in which is housed a seal 4 ensuring the seal between the distributor and the device according to the invention.

Les deux demi-coquilles 1A et 1B se recouvrent partiellement le long de la ligne de joint 6, assurant une étanchéité grâce à une structure en forme de chicane. La paroi interne 66 de la demi-coquille 1B est fixée radialement à celle-ci, avec un décrochement 72. La paroi interne 65 est fixée radialement à la demi-coquille 1A, en extrémité de celle-ci. Elle comporte également un décrochement 73, complémentaire du décrochement 72, qui forment ainsi une chicane 67, 68 et 69 pour le gaz venant de l'intérieur de la coquille et qui s'échapperait vers l'extérieur. Avec une telle perte de charge, le gaz, introduit sous forme d'un flux laminaire dans la coquille par les ouvertures 9, ne peut pratiquement s'échapper par le joint latéral 6.The two half-shells 1A and 1B partially overlap along the joint line 6, ensuring a seal thanks to a structure in the form of a baffle. The inner wall 66 of the half-shell 1B is fixed radially to the latter, with a recess 72. The internal wall 65 is fixed radially to the half-shell 1A, at the end of the latter. It also includes a recess 73, complementary to the recess 72, which thus form a baffle 67, 68 and 69 for the gas coming from inside the shell and which would escape towards the outside. With such a pressure drop, the gas, introduced in the form of a laminar flow into the shell through the openings 9, cannot practically escape through the side seal 6.

A noter que l'extrémité latérale 70 de AB vient porter, au jeu près, après fermeture, contre l'extrémité latérale 71 de la paroi 65.Note that the lateral end 70 of AB comes to bear, after clearance, after closing, against the lateral end 71 of the wall 65.

La référence 10A représente deux variantes de réalisation des moyens aérodynamiques selon l'invention placés à l'extrémité inférieure de la coquille 1. La paroi interne de la demi-coquille 1A est chanfreinée à environ 45°, d'une part, une collerette 52 étant fixée en extrémité, sur la paroi extérieure de la coquille 1, tandis qu'un évasement 352 de diamètre interne D4 prolonge les coquilles 1A, 1B, de diamètre intérieur D2 à leur partie inférieure.The reference 10A represents two alternative embodiments of the aerodynamic means according to the invention placed at the lower end of the shell 1. The internal wall of the half-shell 1A is chamfered at approximately 45 °, on the one hand, a flange 52 being fixed at the end, on the outer wall of the shell 1, while a flaring 352 of internal diameter D 4 extends the shells 1A, 1B, of internal diameter D 2 at their lower part.

La référence 10B montre une variante de réalisation des parois de la coquille 1 permettant d'améliorer encore la protection gazeuse.The reference 10B shows an alternative embodiment of the walls of the shell 1 making it possible to further improve the gas protection.

Les demi-coquilles, telles que 1B, sont entourées, sensiblement de la base du canal annulaire 8 à l'extrémité inférieure de la demi-coquille, par une gaine 70, disposée coaxialement avec les demi-coquilles, de manière à ménager un espace 71 qui communique avec le canal annulaire 8 d'amenée de gaz ou chambre de répartition du gaz. (Cette amenée de gaz pourrait être différente si l'on voulait créer une gaine gazeuse de nature différente).The half-shells, such as 1B, are surrounded, substantially from the base of the annular channel 8 at the lower end of the half-shell, by a sheath 70, arranged coaxially with the half-shells, so as to provide a space 71 which communicates with the annular gas supply channel 8 or gas distribution chamber. (This gas supply could be different if we wanted to create a gas duct of a different nature).

Dans cette variante de réalisation, il est également possible de supprimer la paroi 1B au droit de la paroi 90. De cette manière, un flux de gaz sera engendré par les perforations 9, tandis qu'un second flux sera envoyé par la fente de sortie 71 du canal 8 dirigé vers le bas, pour entourer le jet à ce niveau. Les débits sont ajustés respectivement selon le diamètre des trous et la largeur de la fente.In this alternative embodiment, it is also possible to remove the wall 1B in line with the wall 90. In this way, a gas flow will be generated by the perforations 9, while a second flow will be sent through the outlet slot 71 of channel 8 directed downwards, to surround the jet at this level. The flow rates are adjusted respectively according to the diameter of the holes and the width of the slot.

Cette gaine 70 comporte de préférence une collerette aérodynamique 52 à sa base.This sheath 70 preferably comprises an aerodynamic collar 52 at its base.

Le dispositif de protection étant conçu en particulier pour la coulée continue dans des lingotières de petites dimensions, il n'est pas possible, dans ce cas d'introduire l'extrémité inférieure de la coquille dans le métal compte tenu des dimensions respectives du jet, de la coquille et de l'ouverture de la lingotière. C'est pourquoi, il existe un jeu entre la partie inférieure de la coquille et l'ouverture de coulée, ce jeu permettant de plus la manoeuvre du dispositif en cours de coulée, si cela s'avère nécessaire.The protection device being designed in particular for continuous casting in molds of small dimensions, it is not possible, in this case to introduce the lower end of the shell into the metal taking into account the respective dimensions of the jet, the shell and the opening of the mold. This is why, there is a clearance between the lower part of the shell and the pouring opening, this clearance allowing moreover the operation of the device during casting, if this proves necessary.

En position normale de fonctionnement, la coquille d'inertage 1 centrée sur le jet de coulée 2 est appuyée contre le fond du répartiteur 3, de façon quasi étanche, à l'aide de joint 4 en produit fibreux réfractaire ou métalloplastique, et/ou grâce à la virole circulaire 5.In the normal operating position, the inerting shell 1 centered on the pouring jet 2 is pressed against the bottom of the distributor 3, in an almost leaktight manner, using a seal 4 made of refractory or metalloplastic fibrous product, and / or thanks to the circular ferrule 5.

Les deux demi-coquilles 1A et 1B sont plaquées l'une contre l'autre et l'étanchéité entre elles est assurée par le joint en forme chicane 6 sur toute la longueur du dispositif.The two half-shells 1A and 1B are pressed one against the other and sealing between them is ensured by the baffle-shaped seal 6 over the entire length of the device.

Deux arrivées de gaz 7A et 7B, de diamètre suffisant pour garantir une très faible vitesse d'alimentation en gaz de protection débouchent dans les chambres de répartition 8A et 8B. Le gaz ensuite s'écoule en régime laminaire au travers les trous 9 et gaine le jet de métal jusqu'à la partie inférieure de la coquille.Two gas inlets 7A and 7B, of sufficient diameter to guarantee a very low speed of supply of protective gas lead into the distribution chambers 8A and 8B. The gas then flows in laminar mode through the holes 9 and sheaths the metal jet to the lower part of the shell.

Pour réduire, de façon significative, la dilution du gaz de protection avec l'air ambiant et permettre ainsi une protection efficace sur une plus grande longueur du jet de métal, des moyens aérodynamiques sont utilisés.To significantly reduce the dilution of the shielding gas with the ambient air and thus allow effective protection over a longer length of the metal jet, aerodynamic means are used.

Il consistent essentiellement en un chanfrei- nage (ou un évasement) de la paroi intérieure et l'adjonction d'un déflecteur sur la paroi extérieure de la coquille 1.It essentially consists of a chamfering (or flaring) of the inner wall and the addition of a deflector on the outer wall of the shell 1.

Le déflecteur, par ailleurs, entraîne une meilleure couverture de la partie supérieure de la lingotière assurant ainsi une plus grande efficacité de l'inertage. De plus, on peut adapter les dimensions et la forme du déflecteur aux différents formats des lingotières.The deflector, moreover, results in better coverage of the upper part of the ingot mold thus ensuring greater efficiency of the inerting. In addition, the dimensions and shape of the deflector can be adapted to the different formats of the molds.

Dans le cas d'une régulation de niveau par visée optique et/ou d'introduction d'addition par fil (A1., par exemple), une échancrure peut être ménagée dans un angle de la lingotière.In the case of level regulation by optical sighting and / or introduction of addition by wire (A1., For example), a notch can be formed in a corner of the mold.

La figure 2 est un croquis en perspective représentant les demi-coquilles en position ouverte autour du jet de coulée schématisé par la référence 102.FIG. 2 is a perspective sketch showing the half-shells in the open position around the casting jet shown diagrammatically by the reference 102.

Le dispositif de protection selon l'invention comporte deux demi-coquilles complémentaires 101A et 101B, entourées à leur partie supérieure des chambres de répartition complémentaires 108A et 108B de forme semi-annulaire, reliées respectivement à une alimentation en gaz non représentée sur la figure, et percées d'ouvertures 109 régulièrement réparties sur la surface des demi-coquilles correspondantes 101A et 101B, de manière à permettre le passage du gaz de protection entre les demi-coquilles 101A et 101 Bette jet de coulée 102. Les chambres de répartition 108A et 108B sont fermées à leurs extrémités.The protection device according to the invention comprises two complementary half-shells 101A and 101B, surrounded at their upper part by complementary distribution chambers 108A and 108B of semi-annular shape, connected respectively to a gas supply not shown in the figure, and openings pierced 109 regularly distributed over the surface of the corresponding half-shells 101A and 101B, so as to allow the passage of the shielding gas between the half-shells 101A and 101 Swiss pour casting 102. The distribution chambers 108A and 108B are closed at their ends.

Chaque demi-coquille comporte à sa partie inférieure une demi-collerette 150A et 150B, complémentaires l'une de l'autre. La jonction entre les demi-coquilles d'une part et les demi-collerettes d'autre part se fait à l'aide des plans de jonctions 157 et 158 s'étendant respectivement de la base des chambres de répartition 108A et 108B jusqu'aux demi-collerettes 150A et 150B. Ces plans de jonction ont la forme d'un trapèze-rectangle si la coquille est cylindrique. (Mais cette coquille peut avoir également la forme d'un tronc de cône). Les plans de jonction 157 et 158 ont une épaisseur telle qu'ils chevauchent le plan de joint des deux demi-coquilles formant ainsi une chicane comme décrit sur la figure 1. La demi-collerette 150B est légèrement plus longue que la demi-circonférence de la demi-coquille 101B à sa base. Inversement, la demi-collerette 150A est légèrement moins longue que 101A. Ainsi, la demi-collerette 150B déborde légèrement au-delà des plans de jonction 157 et 158 ce qui permet de prolonger le joint en chicane au niveau des demi-collerettes.Each half-shell has at its lower part a half-flange 150A and 150B, complementary to each other. The junction between the half-shells on the one hand and the half-flanges on the other is done using the junction planes 157 and 158 extending respectively from the base of the distribution chambers 108A and 108B to half-flanges 150A and 150B. These junction planes have the shape of a trapezoid-rectangle if the shell is cylindrical. (But this shell can also have the shape of a truncated cone). Junction planes 157 and 158 are so thick that they overlap the joint plane two half-shells thus forming a baffle as described in FIG. 1. The half-flange 150B is slightly longer than the half-circumference of the half-shell 101B at its base. Conversely, the half-collar 150A is slightly shorter than 101A. Thus, the half-flange 150B projects slightly beyond the junction planes 157 and 158, which makes it possible to extend the chicane joint at the level of the half-flanges.

Dans leur partie supérieure, la chambre de répartition comporte deux gorges annulaires 104 et 1040 pour loger un joint d'étanchéité avec la base du répartiteur.In their upper part, the distribution chamber has two annular grooves 104 and 1040 to accommodate a seal with the base of the distributor.

La figure 3 représente deux vues en coupe du dispositif de la figure 2, en position fermée.Figure 3 shows two sectional views of the device of Figure 2, in the closed position.

Sur la figure 3A (qui est une vue en coupe selon l'axe BB - figure 3B), les mêmes éléments que ceux de la figure 2 portent les mêmes références.In Figure 3A (which is a sectional view along the axis BB - Figure 3B), the same elements as those of Figure 2 have the same references.

On remarquera particulièrement que les deux demi-coquilles 101A et 101B portent sensiblement l'une sur l'autre en 160, 163, 260, 263, et délimitent respectivement des chicanes 161, 162 et 261, 262.It will be noted in particular that the two half-shells 101A and 101B bear substantially one on the other at 160, 163, 260, 263, and delimit baffles 161, 162 and 261, 262 respectively.

La figure 3B, qui est une coupe selon l'axe AA de la figure 3A porte les mêmes références que la figure 3A.Figure 3B, which is a section along the axis AA of Figure 3A has the same references as Figure 3A.

La figure 4A schématise une première variante de réalisation de l'ensemble du dispositif selon l'invention, muni de ses moyens de commande. La coquille 1 comporte une charnière 31 permettant l'ouverture et la fermeture des demi-coquilles autour du jet de coulée (non représenté) dans l'ouverture 30 de la lingotière oscillante. La coquille 1 est reliée via 31 à un premier bras 32 qui pivote horizontalement sur un second bras 34 autour de l'articulation 33. (mouvement 1 le bras vertical 34 coulisse de bas en haut (mouvement 3 sous l'action du vérin 35, permettant de venir plaquer le dispositif 1 sur la répartiteur (non représenté).FIG. 4A shows diagrammatically a first alternative embodiment of the assembly of the device according to the invention, provided with its control means. The shell 1 comprises a hinge 31 allowing the opening and closing of the half-shells around the pouring jet (not shown) in the opening 30 of the oscillating ingot mold. The shell 1 is connected via 31 to a first arm 32 which pivots horizontally on a second arm 34 around the articulation 33. (movement 1 the vertical arm 34 slides from bottom to top (movement 3 under the action of the jack 35, allowing the device 1 to be pressed onto the distributor (not shown).

Auparavant, on aura refermé les demi-coquilles autour du jet de coulée (mouvement 2 sur la figure).Previously, we will have closed the half-shells around the casting jet (movement 2 in the figure).

Dans cette variante, on peut fixer 35 à la table de coulée.In this variant, 35 can be fixed to the casting table.

Sur la variante de la figure 4B, les mêmes éléments portent les mêmes références. Le vérin 35 est fixé sur le répartiteur de coulée 39 et est alimenté en air comprimé (pour les manoeuvres) via 37 et en gaz d'inertage (argon et/ou zote, et/ou anhydride carbonique) via 36.In the variant of FIG. 4B, the same elements have the same references. The jack 35 is fixed to the flow distributor 39 and is supplied with compressed air (for maneuvers) via 37 and inerting gas (argon and / or zote, and / or carbon dioxide) via 36.

Le dispositif de protection est fixé sur un support formant conduite de gaz de protection et comportant une partie mobile permettant l'ouverture des coquilles, celui-ci peut être fixé sur la paroi de la poche ou du répartiteur ainsi que sur tout support solidaire de son berceau, à telle fin de pouvoir manoeuvrer le dispositif d'une façon solidaire de la poche ou du répartiteur; dans certains cas, il est possible de fixer cet ensemble sur la table de coulée.The protection device is fixed on a support forming a protective gas pipe and comprising a movable part allowing the opening of the shells, this can be fixed on the wall of the pocket or of the distributor as well as on any support integral with its cradle, for such purpose to be able to operate the device in a manner integral with the pocket or the distributor; in some cases, it is possible to fix this assembly on the casting table.

Le bras support est fixé sur un tourillon permettant l'échappement du dispositif de protection de jet par une rotation de celui-ci.The support arm is fixed on a journal allowing the exhaust of the jet protection device by a rotation of the latter.

Une fois mis en place, un vérin en appui sur l'extrémité du bras applique le dispositif en demi-coquille sur le fond du répartiteur en exerçant une force d'accostage d'environ 50 deca Newton, pour assurer l'étanchéité dès que le vérin entre en action pour abaisser le dispositif, l'articulation d'ouverture est sollicitée automatiquement par un ressort qui a été tendu à la fermeture à l'aide d'un bras poussant maintenu en place par un dispositif à doigt commandé par ressort.Once in place, a jack resting on the end of the arm applies the half-shell device to the bottom of the distributor, exerting a docking force of approximately 50 deca Newton, to ensure sealing as soon as the actuator goes into action to lower the device, the opening articulation is automatically biased by a spring which has been stretched when closing using a pushing arm held in place by a spring-controlled finger device.

La figure 5 représente un exemple préféré de réalisation des moyens de commande du dispositif selon l'invention.FIG. 5 represents a preferred embodiment of the control means of the device according to the invention.

Les deux demi-coquilles sont schématisées par les repères 401A et 401B en position ouverte correspondant à la position des moyens de commande représentés sur la figure.The two half-shells are shown diagrammatically by the references 401A and 401B in the open position corresponding to the position of the control means shown in the figure.

Ceux-ci comportent une partie principale constituée d'un bras support 435 dont l'extrémité est coudée du côté de la demi-coquille 401 B qui lui est fixée par une rotule 462. Cette dernière se trouve sensiblement à l'extrémité de la partie droite du bras 435.These comprise a main part consisting of a support arm 435, the end of which is bent on the side of the half-shell 401 B which is fixed to it by a ball joint 462. The latter is located substantially at the end of the part right of arm 435.

L'autre demi-coquille 401A est solidaire, par la rotule 461 d'une pluralité de bras articulés 489, dont l'extrémité 431 est coudée autour de la demi-coquille 401A, relié au bras 426 par l'articulation 428, lui-même relié au bras 423, 421 se terminant par une manette de commande 420. Le bras 423, 421 coulisse dans un guide cylindrique 422 ainsi que dans un guide cylindrique 424. Le ressort de rappel 432 fixé au bras 426 en 433 d'une part et au bras 435 en 434 d'autre part maintien les coquielles en position d'ouverture, la butée 425, solidaire du bras 423, 421 s'appuyant contre le guide cylindrique 424 pour limiter la course d'ouverture.The other half-shell 401A is secured, by the ball joint 461 to a plurality of articulated arms 489, the end 431 of which is bent around the half-shell 401A, connected to the arm 426 by the articulation 428, itself even connected to the arm 423, 421 ending with a control handle 420. The arm 423, 421 slides in a cylindrical guide 422 as well as in a cylindrical guide 424. The return spring 432 fixed to the arm 426 at 433 on the one hand and on the arm 435 at 434, on the other hand, keeps the shellfish in the open position, the stop 425 secured to the arm 423, 421 pressing against the cylindrical guide 424 to limit the opening stroke.

Les guides 422 et 424 sont solidaires du bras 423, lui-même fixé par son extrémité droite sur la figure, à un chariot 450 coulissant sur un rail 451 dans le sens de la flèche F. Une poignée de manoeuvre 437 est prévue pour commander la rotation du bras 435 autour de l'axe 0 perpendiculaire au plan de la figure. L'axe 436 permet une rotation du bras 435, de manière à engendrer le mouvement des coquilles de manière à leur faire traverser le plan de la figure.The guides 422 and 424 are integral with the arm 423, itself fixed by its right end in the figure, to a carriage 450 sliding on a rail 451 in the direction of the arrow F. An operating handle 437 is provided for controlling the rotation of the arm 435 about the axis 0 perpendicular to the plane of the figure. The axis 436 allows rotation of the arm 435, so as to generate the movement of the shells so as to make them cross the plane of the figure.

La mise en place du dispositif s'effectue comme suit:

  • On amène les demi-coquilles 401A et 401B à l'aplomb du jet de coulée, de part et d'autre de celui-ci, en faisant coulisser le chariot 450 sur le rail 451 et/ou par rotation autour de l'axe 0 à l'aide de la poignée de manoeuvre 437.
The installation of the device is carried out as follows:
  • The half-shells 401A and 401B are brought into line with the casting jet, on either side of it, by sliding the carriage 450 on the rail 451 and / or by rotation about the axis 0 using the operating handle 437.

La manette de commande 420 est poussée vers la gauche en direction de 422, provoquant la fermeture des demi-coquilles dans la position schématisée en pointillés. (un système de blocage la maintient dans cette position, déverrouillable manuellement).The control lever 420 is pushed to the left in the direction of 422, causing the half-shells to close in the position shown diagrammatically in dotted lines. (a locking system keeps it in this position, unlockable manually).

Enfin, on vient plaquer la coquille sous le répartiteur, par exemple à l'aide d'un vérin qui provoque la rotation du bras 435 autour de l'axe 436. Les demi-coquilles initialement, sous le plan de la figure, ont leur face supérieure qui passe au-dessus du plan de la figure. La référence 401AB représente les deux demi-coquilles fermées amenées dans cette position après rotation du bras 435 autour de l'axe 0 (perpendiculaire au plan de la figure), suivie d'une fermeture des demi-coquilles à l'aide de 420 (puis rotation de 435 autour de l'axe 436).Finally, the shell is placed under the distributor, for example using a jack which causes the arm 435 to rotate about the axis 436. The half-shells initially, under the plane of the figure, have their upper side which passes over above the plane of the figure. The reference 401AB represents the two closed half-shells brought into this position after rotation of the arm 435 around the axis 0 (perpendicular to the plane of the figure), followed by a closing of the half-shells using 420 ( then rotation of 435 around axis 436).

Exemple 1Example 1

Dans le cas d'une coulée d'acier au Si-Mn, dont les billettes ont une section carrée de 105 mm de côté, on utilise une coquille (ou manchon) de protection de diamètre intérieur de 80 mm à sa base sans colerette. Le débit d'azote est de 60 Nm3/h, la consommation spécifique étant égale à environ 5 Nm3/tonne. La partie inférieure de la coquille est placée à une distance moyenne de la lingotière oscillante égale à 50 mm. La vitesse d'éjection du gaz de protection de la coquille au niveau de la périphérie de sa partie inférieure est d'environ 1,5 m/s, et 3,5 m/s environ le long du jet.In the case of a Si-Mn steel casting, the billets of which have a square section of 105 mm on a side, a protective shell (or sleeve) with an internal diameter of 80 mm is used at its base without collar. The nitrogen flow rate is 60 Nm 3 / h, the specific consumption being approximately 5 Nm 3 / tonne. The lower part of the shell is placed at an average distance from the oscillating ingot mold equal to 50 mm. The speed of ejection of the shell protection gas at the periphery of its lower part is approximately 1.5 m / s, and approximately 3.5 m / s along the jet.

Pour ces conditions de fonctionnement et sans utilisation de ventilateur, inutile dans ce cas d'un bon inertage, on mesure les teneurs suivantes en oxygène:

  • - l'intérieur de la coquille <0,5%
  • - à la sortie de la coquille <0,6%
  • - dans la lingotière <0,9%
For these operating conditions and without the use of a fan, useless in this case of good inerting, the following oxygen contents are measured:
  • - the inside of the shell <0.5%
  • - at the exit of the shell <0.6%
  • - in the mold <0.9%

Ces valeurs permettent d'obtenir de bons résultats métallurgiques.These values make it possible to obtain good metallurgical results.

Exemple 2Example 2

On opère dans les mêmes conditions que précédemment avec un débit de 30 Nm3/h. La vitesse de sortie du gaz à la périphérie de la partie inférieure de la coquille est de 0,7 m/s environ, 1,7 m/s à proximité du jet. On obtient des résultats un peu inférieurs aux précédents (la courbe de concentration d'oxygène égale à 1% entre la partie inférieure de la coquille et l'ouverture de la lingotière est légèrement plus proche du jet de coulée que précédemment, mais celui-ci reste parfaitement protégé).The operation is carried out under the same conditions as above with a flow rate of 30 Nm 3 / h. The gas exit velocity at the periphery of the lower part of the shell is about 0.7 m / s, 1.7 m / s near the jet. Results are obtained slightly lower than the previous ones (the oxygen concentration curve equal to 1% between the lower part of the shell and the opening of the ingot mold is slightly closer to the casting jet than previously, but the latter remains perfectly protected).

Cependant, les teneurs en oxygène mesurées dans la lingotière restent généralement supérieures à 1%. Pour des débits inférieurs ou de l'ordre de 30 Nm3/h, on constate que les oscillations de la lingotière induisent une dilution telle qu'il n'est généralement pas possible d'obtenir une teneur en oxygène inférieure à 1%, à proximité du jet, dans la lingotière.However, the oxygen contents measured in the ingot mold generally remain above 1%. For lower flow rates or around 30 Nm 3 / h, it can be seen that the oscillations of the ingot mold induce a dilution such that it is generally not possible to obtain an oxygen content of less than 1%, at near the jet, in the mold.

Exemple 3Example 3

On opère dans les mêmes conditons que précédemment avec un débit de 90 Nm3/g. La vitesse de sortie des gaz est respectivement 2,5 m/s et 5,5 m/s.The operation is carried out under the same conditions as above with a flow rate of 90 Nm 3 / g. The gas exit velocity is 2.5 m / s and 5.5 m / s respectively.

Les résultats sont sensiblement identiques à ceux obtenus dans l'exemple 1 du point de vue concentration en oxygène.The results are substantially identical to those obtained in Example 1 from the point of view of oxygen concentration.

Exemples 4, 5 et 6Examples 4, 5 and 6

On recommence les exemples 1, 2, et 3 en ajoutant une collerette de 6 mm autour de la coquille avec un chanfrein à 45° environ, à sa partie inférieure, parallèlement à l'ouverture de la lingotière.Examples 1, 2 and 3 are repeated by adding a 6 mm flange around the shell with a chamfer at about 45 °, at its lower part, parallel to the opening of the mold.

Les courbes de concentrations à niveau constant d'oxygène autour du jet de coulée sont sensiblement plus éloignées du jet que les courbes correspondantes, en l'absence de collerette, ce qui signifie une légère amélioiration des résultats. L'utilisation d'une collerette peut donc s'avérer utile lorsqu'on cherche à abaisser encore les concentrations en oxygène à proximité du jet.The constant oxygen concentration curves around the casting jet are significantly more distant from the jet than the corresponding curves, in the absence of a collar, which means a slight improvement in the results. The use of a flange can therefore be useful when seeking to further lower the oxygen concentrations near the jet.

Exemples 7, 8 et 9Examples 7, 8 and 9

On recommence les exemples 1, 2 et 3 en formant un évasement dans la partie inférieure de la coquille, évasement augmentant de 12 mm le diamètre inférieur de celle-ci (diamètre interne à la partie inférieure de la coquille de 92 mm environ).Examples 1, 2 and 3 are repeated by forming a flare in the lower part of the shell, flare increasing the lower diameter by 12 mm (internal diameter at the lower part of the shell by approximately 92 mm).

D'une manière générale, on préfère choisir un évasement, de préférence de section circulaire, de hauteur sensiblement égale à l'augmentation du rayon de la coquille. Dans le cas présent, cette hauteur est donc sensiblement égale à 6 mm.In general, it is preferred to choose a flare, preferably of circular section, of height substantially equal to the increase in the radius of the shell. In the present case, this height is therefore substantially equal to 6 mm.

On constate qu'avec un évasement de la coquille dans sa partie inférieure, on obtient des concentrations en oxygène égales à celles des exemples 1, 2 et 3, pour des débits inférieurs, de gaz de protection.It is found that with a flaring of the shell in its lower part, oxygen concentrations equal to those of Examples 1, 2 and 3 are obtained, for lower flow rates, of protective gas.

Claims (5)

1. A device for protection of a jet of liquid metal (2-102) flowing from an outlet orifice of a ladle or distributor into an ingot mould, of the type with a shell (1) comprising two substantially semicylindrical half-shells (1A-1 B, 101A-101B, 401A-401 B) hinged around a vertical axis (31) and at their upper extremity, each comprising a casing (8A-8B, 108A-108B) supplying protective gas, the said shells bearing sealingly against the lower base surface of the ladle or distributor, characterised in that the supply casings (8A-8B, 108A-108B) are arranged on the outside of the said shells (1A-1B, 101A-101B, 401A-401B) with which they are in communication via circumferentially distributed orifices (9-109), in that the axial length of the shells (1A-1B, 101A-101B, 401A―401B) is selected in such a way as to leave a clearance having an axial length smaller than 100 mm between the lower extremity of the shell (1) and the ingot mould when the device is applied against the bottom (3) of the distributor.
2. A protective device according to claim 1, characterised in that the axial length between the lower extremity of the shell (1) and the ingot mould is smaller than 80 mm.
3. Device according to one of claims 1 to 2 characterised in that the junction planes (6) (157-158) of the two half-shells (1A-1B) (101A-101 B) partially overlap one another in such a way as to improve the sealing of the shell.
4. A protective device according to claim 1 characterised in that, at its upper part, it comprises at least one annular joint (4) (104) allowing a seal to be provided between the shell and the casting distributor.
5. A device according to claim 1 intended to be coupled to a casting distributor around its casting orifice, characterised in that it co-operates with a circular ferrule (5) integral with the distributor and intended to improve the gas seal.
EP86401792A 1985-08-14 1986-08-11 Equipment for protecting a liquid-metal jet against oxidation and/or nitriding Expired - Lifetime EP0213042B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86401792T ATE56642T1 (en) 1985-08-14 1986-08-11 DEVICE FOR PROTECTING A LIQUID CASTING STREAM AGAINST OXIDATION AND/OR NITRIDING.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8512378 1985-08-14
FR8512378A FR2586210B1 (en) 1985-08-14 1985-08-14 DEVICE FOR PROTECTION AGAINST OXIDATION AND / OR NITRURATION OF A LIQUID METAL JET AND ITS USE

Publications (3)

Publication Number Publication Date
EP0213042A2 EP0213042A2 (en) 1987-03-04
EP0213042A3 EP0213042A3 (en) 1988-12-07
EP0213042B1 true EP0213042B1 (en) 1990-09-19

Family

ID=9322225

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86401792A Expired - Lifetime EP0213042B1 (en) 1985-08-14 1986-08-11 Equipment for protecting a liquid-metal jet against oxidation and/or nitriding

Country Status (13)

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US (1) US4805688A (en)
EP (1) EP0213042B1 (en)
JP (1) JPS6297759A (en)
KR (1) KR870001888A (en)
AT (1) ATE56642T1 (en)
AU (1) AU594354B2 (en)
BR (1) BR8603875A (en)
CA (1) CA1299837C (en)
DE (1) DE3674293D1 (en)
ES (1) ES2001086A6 (en)
FR (1) FR2586210B1 (en)
PT (1) PT83195B (en)
ZA (1) ZA866054B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2642678A1 (en) * 1989-02-07 1990-08-10 Air Liquide Process for producing a gaseous atmosphere in contact with a metal at high temperature
US5421562A (en) * 1994-04-28 1995-06-06 General Motors Corporation Gas-shielded siphonic valve
US6228187B1 (en) 1998-08-19 2001-05-08 Air Liquide America Corp. Apparatus and methods for generating an artificial atmosphere for the heat treating of materials
US6491863B2 (en) 2000-12-12 2002-12-10 L'air Liquide-Societe' Anonyme A' Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes George Claude Method and apparatus for efficient utilization of a cryogen for inert cover in metals melting furnaces
KR100864444B1 (en) * 2002-04-24 2008-10-20 주식회사 포스코 Device for preventing oxidation of hot iron in continuous casting plant
US20060266793A1 (en) * 2005-05-24 2006-11-30 Caterpillar Inc. Purging system having workpiece movement device
US20190210099A1 (en) * 2017-10-05 2019-07-11 Emirates Steel Industries PJSC Method for continuous casting of two or more long products using a single continuous casting strand

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Publication number Priority date Publication date Assignee Title
US3439735A (en) * 1965-11-19 1969-04-22 Union Carbide Corp Continuous casting apparatus with inert gas protector
US3616843A (en) * 1969-11-25 1971-11-02 Koppers Co Inc Apparatus for shrouding in a continuous casting machine
DE2517834A1 (en) * 1975-04-22 1976-11-04 Linde Ag Continuous casting plant using double gas curtain - to protect molten metal flowing from ladle into mould.
GR61761B (en) * 1975-11-12 1979-01-09 Linde Ag Casting plant
US4084799A (en) * 1976-08-30 1978-04-18 Georgetown Steel Corporation Shrouding apparatus
US4270595A (en) * 1978-09-08 1981-06-02 Georgetown Steel Corporation Shroud with replaceable extension
AT368415B (en) * 1979-02-20 1982-10-11 Voest Alpine Ag INSTALLATION ON A METALLURGICAL TUBE WITH A PROTECTIVE PIPE
JPS5748307A (en) * 1980-09-05 1982-03-19 Toray Silicone Co Ltd Composition of defoaming agent
FR2523007A1 (en) * 1982-03-15 1983-09-16 Air Liquide METHOD AND INSTALLATION FOR PROTECTING A LIQUID METAL CASTING JET
CH660700A5 (en) * 1983-08-12 1987-06-15 Finanz Handels Invest Fhi SHIELDING DEVICE FOR A MOLDING BEAM FROM LIQUID MATERIAL.

Also Published As

Publication number Publication date
JPS6297759A (en) 1987-05-07
ZA866054B (en) 1987-03-25
US4805688A (en) 1989-02-21
DE3674293D1 (en) 1990-10-25
ES2001086A6 (en) 1988-04-16
ATE56642T1 (en) 1990-10-15
AU594354B2 (en) 1990-03-08
KR870001888A (en) 1987-03-28
CA1299837C (en) 1992-05-05
BR8603875A (en) 1987-03-24
FR2586210A1 (en) 1987-02-20
PT83195B (en) 1992-10-30
AU6118286A (en) 1987-02-19
FR2586210B1 (en) 1988-05-13
PT83195A (en) 1986-09-01
EP0213042A2 (en) 1987-03-04
EP0213042A3 (en) 1988-12-07

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