EP0213042A2 - 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
EP0213042A2
EP0213042A2 EP86401792A EP86401792A EP0213042A2 EP 0213042 A2 EP0213042 A2 EP 0213042A2 EP 86401792 A EP86401792 A EP 86401792A EP 86401792 A EP86401792 A EP 86401792A EP 0213042 A2 EP0213042 A2 EP 0213042A2
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EP
European Patent Office
Prior art keywords
shells
jet
sleeve
shell
distributor
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
EP86401792A
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German (de)
French (fr)
Other versions
EP0213042B1 (en
EP0213042A3 (en
Inventor
Jean Foulard
Jacques Nicolas
Jean-François Mignot
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Publication date
Application filed by Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Priority to AT86401792T priority Critical patent/ATE56642T1/en
Publication of EP0213042A2 publication Critical patent/EP0213042A2/en
Publication of EP0213042A3 publication Critical patent/EP0213042A3/en
Application granted granted Critical
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 a method of protection against oxidation and / or nitriding of a jet of liquid metal flowing from the outlet orifice of a pocket or a distributor in an oscillating ingot mold, method in which the casting jet is surrounded, over at least part of its height, with a sleeve into which a gas protecting the liquid metal is injected so as to limit the contact of the latter with the ambient air between the orifice and the oscillating ingot mold.
  • It also relates to a device for implementing such a method as well as to the use of this device.
  • the invention applies more particularly to continuous casting, in particular to continuous casting of small dimensions.
  • Continuous casting installations generally include one or more vertical jets which fall into a vertically oscillating mold.
  • the liquid metal is likely to oxidize and / or to nitride. Consequently, it has already been envisaged to protect the metal against such reactions by surrounding it, for most of its free fall, with a sheath or crown of neutral gas such as argon, nitrogen, carbon dioxide, etc.
  • a sheath or crown of neutral gas such as argon, nitrogen, carbon dioxide, etc.
  • the devices known at present have a certain number of drawbacks, in particular with regard to the difficulties of sealing, setting up, keeping over time and preserving the protective neutral gas.
  • Devices of this type include a circular sleeve surrounding the pouring jet, a sleeve widening at its lower part so as to come to rest on the table surrounding the oscillating ingot mold, the internal diameter of the lower part of said sleeve being, here again, greater than the width of the oscillating ingot mold. If this avoids the entry of air from below and therefore the phenomenon of progressive dilution of the shielding gas during its descent along the casting jet, it generates with such a system, a significant suction from above. Ambiant air. Indeed, the shielding gas sent downwards, in the same direction as the casting jet, cannot oppose the aspiration of ambient air, taking into account the significant differences in gas temperatures near the jet and ambient air. Turbulence is thus created near the pouring jet and the latter is thus, in places, directly in contact with the ambient air. In the absence of any indication as to the flow rate of shielding gas, it is not possible to thus achieve the aim set by the invention.
  • the present invention aims to remedy these drawbacks by providing an effective protection method as well as a device which can be easily installed during the flow of the liquid metal. and making it possible to obtain, for low gas consumption, excellent metallurgical results.
  • the protection method according to the invention is characterized in that the protective sleeve is integral with the pocket or the distributor and has a length such that the maximum distance D 1 between its lower end and the oscillating ingot mold, when the latter is in the low position, is less than 100 millimeters and in that the protective gas is injected into the sleeve so as to surround the pouring jet and escape towards the outside by the lower end of said sleeve with an average speed of gases evacuated near the lower end of the sleeve of between about 0.7 m / s and 5.5 m / s, so as to limit, on the one hand, the dilution of the shielding gas with the air in one any point located near the casting jet and, on the other hand, the suction of ambient air towards the casting jet.
  • the distance D 1 is less than or equal to 80 min.
  • the sleeve has a circular section in the plane perpendicular to the casting jet, the diameter D 2 of the sleeve at its lower part is preferably less and at most equal to the width of the oscillating ingot mold.
  • a collar placed near the lower part of the sleeve will be used, surrounding said sleeve substantially over its entire periphery, the diameter D 2 of the sleeve being chosen so that the diameter D 3 of the collar is preferably smaller and at most equal to the width of the oscillating ingot mold, this flange being preferably oriented parallel to the opening of the ingot mold.
  • the sleeve is provided, in its lower part, with a flare over its entire periphery, the diameter of the sleeve being chosen to be so that the diameter D 4 of the flare is preferably less than the width of the oscillating ingot mold.
  • the device according to the invention comprises, under the bottom and around the outlet orifice, an opening inerting shell, formed of two half-shells, which can be applied against the bottom of the pocket and / or the distribution basket and which injects shielding gas at low velocity, uniformly around the metal jet over most of its height; this is carried out in such a way that the sealing of the junction plane of the half-shells guarantees good sealing throughout the metal jet.
  • a suitable aerodynamic device such as a flange or a lower flaring making it possible to reduce the dilution and / or the aspiration of the protective gas by the ambient air.
  • the device according to the invention is characterized in that the means for surrounding the pouring jet consist firstly of two complementary half-shells and secondly of means of articulation of said half-shells allowing the opening and closing of these.
  • the aerodynamic deflection means preferably comprise a flange formed of two half-flanges, each integral with a half-shell, and / or a chamfered part, located at the lower end of the internal wall of each half-shell in direction of an external wall.
  • the flange and / or the chamfer will be replaced by a flaring of the lower part of the shells.
  • the junction planes of the two half-shells partially overlap so as to improve the tightness of the shell.
  • the device according to the invention comprises a concentric sheath placed around the half-shells and formed of two complementary half-sheaths, each being integral with its corresponding half-shell, the space between the sheath and the half-shells being connected to means for injecting a protective gas.
  • the device comprises at its upper part at least one annular seal making it possible to seal between the shell and the tundish under which it is to be placed.
  • the device When the device is intended to be coupled to a flow distributor around the pouring orifice thereof, it can cooperate with a circular ferrule, integral with the distributor and intended to improve the gas tightness of the coupling.
  • the articulation means of the half-shells are constituted by a hinge.
  • the articulation means of the half-shells consist of a set of articulated arms making it possible to move the half-shells away from each other, said articulated arms being controlled by control means.
  • a movable arm which is integral with it at one end and connected to means for pressing said shell against the distributor.
  • gases used for protecting 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, anhydride carbonic, 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 protective 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 the person skilled in the art, by simple routine experiments, depending on the result that one wants 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 ingot 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 also permitting 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 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.
  • They essentially consist of a chamfer (or a flare) of the interior wall and the addition of a deflector on the exterior wall of the shell 1.
  • 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 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 101B and the casting jet 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 hand is done using the junction planes 157 and 158 extending respectively from the base of the distribution chambers 108A and 108B to the 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).
  • the junction planes 157 and 158 have a thickness such that they overlap the joint plane of the two half-shells thus forming a cam baffle 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 150 A 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 means of control.
  • 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, making it possible to press the device 1 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 support arm 435 whose end is bent on the side of the half-shell 401B which is fixed to it by a ball joint 462.
  • the latter is located substantially at the end of the straight part 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 arm 423, 421 ending with a joystick controls 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 to the arm 435 at 434 on the other hand holds the shells in the open position, the stop 425 secured to the arm 423, 421 pressing against the cylindrical guide 424 to limit the opening stroke.
  • 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 face which passes 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 3 being approximately 5 Nm / 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 / 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.
  • 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)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
  • Forging (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Jet Pumps And Other Pumps (AREA)
  • Gas Separation By Absorption (AREA)
  • Chemically Coating (AREA)
  • Catching Or Destruction (AREA)
  • Disintegrating Or Milling (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 un procédé de protection contre l'oxydation et/ou la nitruration d'un jet de métal liquide s'écoulant de l'orifice de sortie d'une poche ou d'un répartiteur dans une lingotière oscillante, procédé dans lequel on entoure le jet de coulée, sur une partie au moins 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 oscillante.The present invention relates to a method of protection against oxidation and / or nitriding of a jet of liquid metal flowing from the outlet orifice of a pocket or a distributor in an oscillating ingot mold, method in which the casting jet is surrounded, over at least part of its height, with a sleeve into which a gas protecting the liquid metal is injected so as to limit the contact of the latter with the ambient air between the orifice and the oscillating ingot mold.

Elle se rapporte également à un dispositif de mise en oeuvre d'un tel procédé ainsi qu'à l'utilisation de ce dispositif.It also relates to a device for implementing such a method as well as to the use of this device.

L'invention s'applique plus particulièrement à la coulée continue, en particulier à la coulée continue de petites dimensions.The invention applies more particularly to continuous casting, in particular to continuous casting of small dimensions.

Les installations de coulée continue comprennent généralement un ou plusieurs jets verticaux qui tombent dans une lingotière oscillant verticalement. Pendant sa chute libre, du répartiteur (ou de la poche) dans la lingotière, le métal liquide est susceptible de s'oxyder et/ou de se nitrurer. Par conséquent, on a déjà envisagé de protéger le métal contre de telles réactions en l'entourant, sur la plus grande partie de sa chute libre, par une gaine ou couronne de gaz neutre tel que l'argon, l'azote, l'anhydride carbonique, etc... Toutefois, les dispositifs connus actuellement présentent un certain nombre d'inconvénients, notamment en ce qui concerne les difficultés d'étanchéité, de mise en place, de tenue dans le temps et de consannation du gaz neutre protecteur.Continuous casting installations generally include one or more vertical jets which fall into a vertically oscillating mold. During its free fall, from the distributor (or the pocket) in the ingot mold, the liquid metal is likely to oxidize and / or to nitride. Consequently, it has already been envisaged to protect the metal against such reactions by surrounding it, for most of its free fall, with a sheath or crown of neutral gas such as argon, nitrogen, carbon dioxide, etc. However, the devices known at present have a certain number of drawbacks, in particular with regard to the difficulties of sealing, setting up, keeping over time and preserving the protective neutral gas.

En particulier, dans la coulée continue pour former des billettes de petites sections, on utilise généralement un tube que l'on place autour du jet de coulée. Mais ces tubes doivent être changés fréquemment, car la manoeuvre du répartiteur les endommage. De plus, leur fixation, après début de la coulée provoque des projections. Enfin, il n'est pas aisé de les enlever en cas de problèmes.In particular, in continuous casting to form billets of small sections, a tube is generally used which is placed around the casting jet. But these tubes must be changed frequently, because the operation of the distributor damages them. In addition, their fixing, after the start of casting causes projections. Finally, it is not easy to remove them in case of problems.

Cependant, quel que soit le dispositif utilisé actuellement connu, il se pose des problèmes de dilution du gaz de protection, d'une part, et d'aspiration d'air, d'autre part. Le problème de dilution se pose essentiellement lors de l'utilisation de dispositifs tels que décrits dans les brevets américains 4 084 799 ou 4 102 386. Dans le brevet US 4 084 799, le manchon cylindrique de protection est solidaire du répartiteur ou de la poche, de manière sensiblement étanche. Carpte tenu d'une distance habituelle de l'ordre d'une quarantaine de centimètres entre le répartiteur et la position moyenne de la lingotière oscillante, ce dispositif qui a une longueur sensiblement égale à la moitié de cette distance se trouve donc à environ vingt centimètres de la lingotière oscillante. De plus, le diamètre interne du manchon., à sa partie inférieure, apparaît légèrement supérieur à la largeur de la lingotière oscillante. Enfin, aucune indication n'est donnée dans ce brevet quant à la manière d'injecter le gaz dans le manchon pour éviter la dilution de ce gaz avec l'air ambiant lorsque ledit gaz sort du manchon de protection. On a constaté, en pratique, qu'avec une telle géométrie du manchon, on ne pouvait généralement pas atteindre le but fixé par l'invention, à savoir une concentration en oxygène autour du jet de coulée jusqu'au pied de jet dans la lingotière, inférieure à environ 1 %.However, whatever the device currently known, there are problems of dilution of the protective gas, on the one hand, and air suction, on the other hand. The dilution problem essentially arises when using devices as described in American patents 4,084,799 or 4,102,386. In US patent 4,084,799, the cylindrical protective sleeve is integral with the distributor or the pocket , substantially sealed. Frame kept at a usual distance of around forty centimeters between the distributor and the average position of the mold oscillating, this device which has a length substantially equal to half this distance is therefore approximately twenty centimeters from the oscillating ingot mold. In addition, the internal diameter of the sleeve, at its lower part, appears slightly greater than the width of the oscillating ingot mold. Finally, no indication is given in this patent as to how to inject the gas into the sleeve to avoid dilution of this gas with ambient air when said gas leaves the protective sleeve. It has been found, in practice, that with such a geometry of the sleeve, it was generally not possible to achieve the goal set by the invention, namely an oxygen concentration around the casting jet up to the jet foot in the ingot mold. , less than about 1%.

Le problème d'aspiration d'air se pose essentiellement lors de l'utilisation de dispositifs tels que décrits dans le brevet US 3 439 735.The problem of air intake essentially arises when using devices as described in US Pat. No. 3,439,735.

Les dispositifs de ce type comportent un manchon circulaire entourant le jet de coulée, manchon s'élargissant à sa partie inférieure de manière à venir reposer sur la table entourant la lingotière oscillante, le diamétre intérieur de la partie inférieure dudit manchon étant, là encore, supérieur à la largeur de la lingotière oscillante. Si l'on évite ainsi les entrées d'air par le bas et donc le phénomène de dilution progressive du gaz de protection lors de sa descente de long du jet de coulée, on engendre avec un tel systéme, une importante aspiration par le haut de l'air ambiant. En effet, le gaz de protection envoyé vers le bas, dans le même sens que le jet de coulée, ne peut s'opposer à l'aspiration de l'air ambiant, compte tenu des différences importantes de températures du gaz à proximité du jet et de l'air ambiant. Il se crée ainsi des turbulences à proximité du jet de coulée et celui-ci est ainsi, par endroits, directement au contact de l'air ambiant. En l'absence de quelconques indications quant au débit de gaz de protection, il n'est pas possible d'atteindre ainsi le but fixé par l'invention.Devices of this type include a circular sleeve surrounding the pouring jet, a sleeve widening at its lower part so as to come to rest on the table surrounding the oscillating ingot mold, the internal diameter of the lower part of said sleeve being, here again, greater than the width of the oscillating ingot mold. If this avoids the entry of air from below and therefore the phenomenon of progressive dilution of the shielding gas during its descent along the casting jet, it generates with such a system, a significant suction from above. Ambiant air. Indeed, the shielding gas sent downwards, in the same direction as the casting jet, cannot oppose the aspiration of ambient air, taking into account the significant differences in gas temperatures near the jet and ambient air. Turbulence is thus created near the pouring jet and the latter is thus, in places, directly in contact with the ambient air. In the absence of any indication as to the flow rate of shielding gas, it is not possible to thus achieve the aim set by the invention.

On retrouve les deux phénomènes de dilution du gaz de protection et d'aspiration d'air lors de l'utilisation du dispositif décrit dans le brevet américain 3 908 734.We find the two phenomena of dilution of the protective gas and air suction when using the device described in American patent 3,908,734.

La présente invention vise à remédier à ces inconvénients en procurant un procédé de protection efficace ainsi qu'un dispositif pouvant être aisément mis en place pendant l'écoulement du métal liquide et permettant d'obtenir, pour une faible consommation de gaz, d'excellents résultats métallurgiques.The present invention aims to remedy these drawbacks by providing an effective protection method as well as a device which can be easily installed during the flow of the liquid metal. and making it possible to obtain, for low gas consumption, excellent metallurgical results.

Le procédé de protection selon l'invention est caractérisé en ce que le manchon de protection est solidaire de la poche ou du répartiteur et a une longueur telle que la distance maximale D1 entre son extrémité inférieure et la lingotière oscillante, lorsque celle-ci est en position basse, est inférieure à 100 millimètres et en ce que le gaz de protection est injecté dans le manchon de manière à entourer le jet de coulée et s'évacuer vers l'extérieur par l'extrémité inférieure dudit manchon avec une vitesse moyenne des gaz évacués à proximité de l'extrémité inférieure du manchon comprise entre environ 0,7 m/s et 5,5 m/s, de manière à limiter, d'une part, la dilution du gaz de protection avec l'air en un point quelconque situé à proximité du jet de coulée et, d'autre part, l'aspiration de l'air ambiant vers le jet de coulée.The protection method according to the invention is characterized in that the protective sleeve is integral with the pocket or the distributor and has a length such that the maximum distance D 1 between its lower end and the oscillating ingot mold, when the latter is in the low position, is less than 100 millimeters and in that the protective gas is injected into the sleeve so as to surround the pouring jet and escape towards the outside by the lower end of said sleeve with an average speed of gases evacuated near the lower end of the sleeve of between about 0.7 m / s and 5.5 m / s, so as to limit, on the one hand, the dilution of the shielding gas with the air in one any point located near the casting jet and, on the other hand, the suction of ambient air towards the casting jet.

La Demanderesse pense, sans pour autant vouloir être liée par une quelconque théorie, qu'un tel procédé perniet au gaz de protection de suivre le jet de coulée jusqu'à la surface du métal liquide dans la lingotière et remonter ensuite pour s'évacuer entre la partie inférieure du manchon de protection et la partie supérieure de la lingotière, repoussant ainsi l'air vers l'extérieur.The Applicant thinks, without wishing to be bound by any theory, that such a process allows the shielding gas to follow the pouring jet to the surface of the liquid metal in the ingot mold and then to rise to evacuate between the lower part of the protective sleeve and the upper part of the mold, thus pushing the air outwards.

- De préférence, la distance D1 est inférieure ou égale à 80 mn.- Preferably, the distance D 1 is less than or equal to 80 min.

Selon un mode préférentiel de réalisation, le manchon a une section circulaire dans le plan perpendiculaire au jet de coulée, le diamètre D2 du manchon à sa partie inférieure étant de préférence inférieur et au plus égal à la largeur de la lingotière oscillante.According to a preferred embodiment, the sleeve has a circular section in the plane perpendicular to the casting jet, the diameter D 2 of the sleeve at its lower part is preferably less and at most equal to the width of the oscillating ingot mold.

De préférence également, on utilisera une collerette placée à proximité de la partie inférieure du manchon, entourant ledit manchon sensiblement sur toute sa périphérie, le diamètre D2 du manchon étant choisi de sorte que le diamètre D3 de la collerette soit de préférence inférieur et au plus égal à la largeur de la lingotière oscillante, cette collerette étant orientée préférentiellement parallèlement à l'ouverture de la lingotière.Preferably also, a collar placed near the lower part of the sleeve will be used, surrounding said sleeve substantially over its entire periphery, the diameter D 2 of the sleeve being chosen so that the diameter D 3 of the collar is preferably smaller and at most equal to the width of the oscillating ingot mold, this flange being preferably oriented parallel to the opening of the ingot mold.

Selon une autre variante de l'invention permettant notamment de réduire les consommations, toutes choses égales par ailleurs, le manchon est muni, dans sa partie inférieure, d'un évasement sur l'ensemble de sa périphérie, le diamètre du manchon étant choisi de sorte que le diamètre D4 de l'évasement soit de préférence inférieur à la largeur de la lingotiëre oscillante.According to another variant of the invention making it possible in particular to reduce consumption, all other things being equal, the sleeve is provided, in its lower part, with a flare over its entire periphery, the diameter of the sleeve being chosen to be so that the diameter D 4 of the flare is preferably less than the width of the oscillating ingot mold.

Le dispositif selon l'invention comprend, sous le fond et autour de l'orifice de sortie, une coquille d'inertage, ouvrante, formée de deux demi-coquilles, pouvant être appliquée contre le fond de la poche et/ou du panier répartiteur et qui assure l'injection de gaz de protection à faible vélocité, uniformément autour du jet de métal sur la majeure partie de sa hauteur ; celle-ci est réalisée de telle façon que l'étanchéité du plan de jonction des demi-coquilles garantit une bonne étanchéité tout au long du jet de métal. Elle est de préférence pourvue à sa partie inférieure d'un dispositif aérodynamique approprié tel qu'une collerette ou un évasement inférieur permettant de réduire la dilution et/ou l'aspiration du gaz de protection par l'air ambiant.The device according to the invention comprises, under the bottom and around the outlet orifice, an opening inerting shell, formed of two half-shells, which can be applied against the bottom of the pocket and / or the distribution basket and which injects shielding gas at low velocity, uniformly around the metal jet over most of its height; this is carried out in such a way that the sealing of the junction plane of the half-shells guarantees good sealing throughout the metal jet. It is preferably provided at its lower part with a suitable aerodynamic device such as a flange or a lower flaring making it possible to reduce the dilution and / or the aspiration of the protective gas by the ambient air.

Le dispositif selon l'invention est caractérisé en ce que les moyens pour entourer le jet de coulée sont constitués d'une part, par deux demi-ooquilles complémentaires et d'autre part, par des moyens d'articulation desdites demi-coquilles permettant l'ouverture et la fermeture de celles-ci.The device according to the invention is characterized in that the means for surrounding the pouring jet consist firstly of two complementary half-shells and secondly of means of articulation of said half-shells allowing the opening and closing of these.

De préférence, il comporte des moyens de déflectian aérodynamiques, placés près de la partie inférieure des demi-coquilles. Les moyens de déflection aérodynamiques comportent de préférence, une collerette formée de deux demi-collerettes, chacune solidaire d'une demi-coquille, et/ou une partie chanfreinée, située à l'extrémité inférieure de la paroi interne de chaque demi-coquille en direction d'une paroi externe. Selon une variante de réalisation, on remplacera la colerette et/ou le chanfrein par un évasement de la partie inférieure des coquilles.Preferably, it comprises aerodynamic deflectian means, placed near the lower part of the half-shells. The aerodynamic deflection means preferably comprise a flange formed of two half-flanges, each integral with a half-shell, and / or a chamfered part, located at the lower end of the internal wall of each half-shell in direction of an external wall. According to an alternative embodiment, the flange and / or the chamfer will be replaced by a flaring of the lower part of the shells.

De préférence, les plans de jonctions des deux demi-coquilles se recouvrent partiellement de manière à améliorer l'étanchéité de la coquille.Preferably, the junction planes of the two half-shells partially overlap so as to improve the tightness of the shell.

Selon une variante de réalisation, le dispositif selon l'invention comporte une gaine concentrique placée autour des demi-coquilles et formée de deux demi-gaines complémentaires, chacune étant solidaire de sa demi-coquille correspondante, l'espace située entre la gaine et les demi-coquilles étant relié à des moyens d'injection d'un gaz protecteur.According to an alternative embodiment, the device according to the invention comprises a concentric sheath placed around the half-shells and formed of two complementary half-sheaths, each being integral with its corresponding half-shell, the space between the sheath and the half-shells being connected to means for injecting a protective gas.

Selon un autre aspect de l'invention, il comporte à sa partie supérieure au moins un joint annulaire permettant d'assurer l'étanchéité entre la coquille et le répartiteur de coulée sous lequel il doit être placée. Lorsque le dispositif est destiné à être accouplé à un répartiteur de coulée autour de l'orifice de coulée de celui-ci, il peut coopérer avec une virole circulaire, solidaire du répartiteur et destinée à améliorer l'étanchéité au gaz de l'accouplement.According to another aspect of the invention, it comprises at its upper part at least one annular seal making it possible to seal between the shell and the tundish under which it is to be placed. When the device is intended to be coupled to a flow distributor around the pouring orifice thereof, it can cooperate with a circular ferrule, integral with the distributor and intended to improve the gas tightness of the coupling.

Selon une première variante de réalisation, les moyens d'articulation des demi-coquilles sont constitués par une charnière.According to a first alternative embodiment, the articulation means of the half-shells are constituted by a hinge.

Selon une seconde variante, les moyens d'articulation des demi-coquilles sont constitués par un ensemble de bras articulés permettant d'éloigner les demi-coquilles l'une de l'autre, lesdits bras articulés étant commandés par des moyens de commande.According to a second variant, the articulation means of the half-shells consist of a set of articulated arms making it possible to move the half-shells away from each other, said articulated arms being controlled by control means.

Dans un mode de réalisation particulièrement bien adapté à l'industrie métallurgique, il comporte un bras mobile qui lui est solidaire à une extrémité et relié à des moyens pour plaquer ladite coquille contre le répartiteur.In an embodiment particularly well suited to the metallurgical industry, it comprises a movable arm which is integral with it at one end and connected to means for pressing said shell against the distributor.

Bien entendu, 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.Of course, the gases used for protecting 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, anhydride carbonic, 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 protsction selon l'invention comporte une coquille 1 constituée de deux demi-coquilles lA, 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'home de métier, par de simples expériences de routine, en fonction du résultat que l'on veut obtenir et du débit de gaz inerte).The protective 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 the person skilled in the art, by simple routine experiments, depending on the result that one wants 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 lA, 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 lA, 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 lingotiéres 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 permttant de plus la manoeuvre du dispositif en cours de coulée, si cela s'avëre nécessaire.The protection device being designed in particular for continuous casting in ingot 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 also permitting 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 effieace sur une plus grande longueur du jet de métal, des moyens aérodynamiques sont utilisés.Aerodynamic means are used 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.

Ils consistent essentiellement en un chanfreinage (ou un évasanent) de la paroi intérieure et l'adjonction d'un déflecteur sur la paroi extérieure de la coquille 1.They essentially consist of a chamfer (or a flare) of the interior wall and the addition of a deflector on the exterior 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 (Al., 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 (Al., 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 percêes 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 101B et le 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 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 101B and the casting jet 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 came 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 150 A 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 hand is done using the junction planes 157 and 158 extending respectively from the base of the distribution chambers 108A and 108B to the 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). The junction planes 157 and 158 have a thickness such that they overlap the joint plane of the two half-shells thus forming a cam baffle 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 150 A 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 cortmande. 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 le répartiteur (non représenté).FIG. 4A shows diagrammatically a first alternative embodiment of the assembly of the device according to the invention, provided with its means of control. 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, making it possible to press the device 1 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'extrfinité 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 401B 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 whose end is bent on the side of the half-shell 401B which is fixed to it by a ball joint 462. The latter is located substantially at the end of the straight part 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 coquilles 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 arm 423, 421 ending with a joystick controls 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 to the arm 435 at 434 on the other hand holds the shells 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 40lA 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 40lA 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 face which passes 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 3 étant égale à environ 5 Nm /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 3 being approximately 5 Nm / 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 :

Figure imgb0001
For these operating conditions and without the use of a fan, useless in this case of good inerting, the following oxygen contents are measured:
Figure imgb0001

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 Nm/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 / 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/h. La vitesse de sortie des gaz est respectivement 2,5 m/s et 5,5 m/s.We operate under the same conditions as above with a flow rate of 90 Nm3 / h. 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 êvasement 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 can be seen 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 (20)

1. Procédé de protection contre l'oxydation et/ou la nitruration d'un jet de métal liquide s'écoulant de l'orifice de sortie d'une poche ou d'un répartiteur dans une lingotière oscillante, procédé dans lequel on entoure le jet de coulée, sur une partie au moins 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 oscillante, caractérisé en ce que la manchon de protection est solidaire de la poche ou du répartiteur et a une longueur telle que la distance maximale D1 entre son extrémité inférieure et la lingotière oscillante, lorsque celle-ci est en position basse est inférieure à 100 millimètres et en ce que le gaz de protection est injecté dans le manchon de manière à entourer le jet de coulée et s'évacuer vers l'extérieur par l'extrémité inférieure dudit manchon avec une vitesse moyenne des gaz évacués à proximité de l'extrémité inférieure du manchon comprise entre environ 0,7 m/s et 5,5 m/s, de manière à limiter, d'une part, la dilution du gaz de protection avec l'air en un point quelconque situé à proximité du jet de coulée et, d'autre part, l'aspiration de l'air ambiant vers le jet de coulée.1. A method of protection against oxidation and / or nitriding of a jet of liquid metal flowing from the outlet orifice of a pocket or a distributor in an oscillating ingot mold, a process in which the casting jet, over at least part of its height, of a sleeve into which a liquid metal shielding gas is injected so as to limit the contact of the latter with ambient air between the outlet orifice and the oscillating ingot mold, characterized in that the protective sleeve is integral with the pocket or the distributor and has a length such that the maximum distance D 1 between its lower end and the oscillating ingot mold, when the latter is in the lower position is lower at 100 millimeters and in that the protective gas is injected into the sleeve so as to surround the pouring jet and escape towards the outside by the lower end of said sleeve with an average speed of the gases evacuated near the bottom end of the m ring between approximately 0.7 m / s and 5.5 m / s, so as to limit, on the one hand, the dilution of the shielding gas with the air at any point located near the casting jet and , on the other hand, the suction of ambient air to the casting jet. 2. Procédé selon la revendication 1, caractérisé en ce que la distance D1 est inférieure ou égale à 80 m/m.2. Method according to claim 1, characterized in that the distance D 1 is less than or equal to 80 m / m. 3. Procédé selon l'une des revendications 1 ou 2, caractérisé en ce que le manchon a une seciton circulaire dans le plan perpendiculaire au jet de coulée, le diamètre D2 du manchon à sa partie inférieure étant de préférence inférieur et au plus égal à la largeur de la lingotière oscillante.3. Method according to one of claims 1 or 2, characterized in that the sleeve has a circular section in the plane perpendicular to the casting jet, the diameter D 2 of the sleeve at its lower part is preferably less and at most equal to the width of the oscillating ingot mold. 4. Procédé selon l'une des revendications 1 à 3, caractérisé en ce qu'une collerette est placée à proximité de la partie inférieure du manchon, entourant ledit manchon sensiblement sur toute sa périphérie, le diamètre du manchon étant choisi de sorte que le diamètre D3 de la collerette soit de préférence inférieur et au plus égal à la largeur de la lingotière oscillante.4. Method according to one of claims 1 to 3, characterized in that a flange is placed near the lower part of the sleeve, surrounding said sleeve substantially over its entire periphery, the diameter of the sleeve being chosen so that the diameter D 3 of the collar is preferably less than and at most equal to the width of the oscillating ingot mold. 5. Procédé selon la revendication précédente, caractérisé en ce que la collerette est orientée sensiblement parallèlement au plan de la lingotière.5. Method according to the preceding claim, characterized in that the collar is oriented substantially parallel to the plane of the mold. 6. Procédé selon l'une des revendications 1 à 3, caractérisé en ce que le manchon est muni dans sa partie inférieure d'un évasement, sur toute sa périphérie, le diamètre du manchon étant choisi de sorte que le diamètre D4 de l'évasement soit de préférence inférieur à la largeur de la lingotière oscillante.6. Method according to one of claims 1 to 3, characterized in that the sleeve is provided in its lower part with a flare, over its entire periphery, the diameter of the sleeve being chosen so that the diameter D 4 of l flaring is preferably less than the width of the oscillating ingot mold. 7. Dispositif de protection contre l'oxydation et/ou la nitruration d'un jet (2) de métal liquide s'écoulant à partir de l'orifice de sortie d'une poche ou d'un repartiteur ( 3 ) , comportant des moyens (lA, 1B) pour entourer le jet de coulée (2) sur une partie au moins de sa hauteur et des moyens (8A, 8B) pour l'injection d'un gaz protecteur au moins autour du jet de coulée (2) de manière à minimiser le contact du métal fondu avec l'air ambiant, caractérisé en ce que les moyens pour entourer le jet de coulée sont constitués d'une part, par deux demi-coquilles complémentaires (lA, 1B) et d'autre part, par des moyens d'articulation (31) desdites demi-coquilles permettant l'ouverture et la fermeture de celles-ci.7. Device for protection against oxidation and / or nitriding of a jet (2) of liquid metal flowing from the outlet orifice of a pocket or of a distributor (3), comprising means (1A, 1B) for surrounding the pouring jet (2) over at least part of its height and means (8A, 8B) for injecting a protective gas at least around the pouring jet (2) so as to minimize the contact of the molten metal with the ambient air, characterized in that the means for surrounding the pouring jet consist on the one hand, by two complementary half-shells (1A, 1B) and on the other hand , by means of articulation (31) of said half-shells allowing the opening and closing of the latter. 8. Dispositif de protection selon la revendication 7, caractérisé en ce qu'il ccmporte des moyens de déflection aérodynamiques (51,52) placés prés de la partie inférieure des demi-coquilles (lA, 1B).8. Protective device according to claim 7, characterized in that it ccmporte aerodynamic deflection means (51,52) placed near the lower part of the half-shells (lA, 1B). 9. Dispositif selon la revendication 8, caractérisé en ce que les moyens de déflection aérodynamiques (51, 52) comportent une collerette (52) formée de deux demi-collerettes, chacune solidaire d'une demi-coquille (lA, 1B).9. Device according to claim 8, characterized in that the aerodynamic deflection means (51, 52) comprise a flange (52) formed of two half-flanges, each integral with a half-shell (lA, 1B). 10. Dispositif selon l'une des revendications 7 à 9, caractérisé en ce que les moyens de déflection (51, 52) comportent une partie chanfreinée (51) située à l'extrémité inférieure de la paroi interne de chaque demi-coquille (lA, 1B) en direction d'une paroi externe.10. Device according to one of claims 7 to 9, characterized in that the deflection means (51, 52) comprise a chamfered part (51) located at the lower end of the internal wall of each half-shell (lA , 1B) towards an external wall. 11. Dispositif de protection selon l'une des revendications 7 à 10, caractérisé en ce qu'il colporte une gaine concentrique (70) placée autour des demi-coquilles (lA, 1B) et formée de deux demi-gaines ccnplémentaires, chacune étant solidaire de sa demi-coquille correspondante, l'espace (71) situé entre la gaine et les demi-coquilles étant relié à des moyens d'injection (8A, 8B)d'un gaz protecteur.11. Protective device according to one of claims 7 to 10, characterized in that it peddles a concentric sheath (70) placed around the half-shells (lA, 1B) and formed of two half-sheaths ccnplémentaires, each being secured to its corresponding half-shell, the space (71) located between the sheath and the half-shells being connected to injection means (8A, 8B) of a protective gas. 12. Dispositif selon l'une des revendications 7 à 11, caractérisé en ce que les plans de jonctions des deux demi-coquilles se recouvrent partiellement de manière à améliorer l'étanchéité de la coquille.12. Device according to one of claims 7 to 11, characterized in that the junction planes of the two half-shells are partially cover so as to improve the tightness of the shell. 13. Dispositif de protection selon l'une des revendications 7 à 12, caractérisé en ce qu'il comporte à sa partie supérieure au moins un joint annulaire (4) permettant d'assurer l'étanchéité entre la coquille (lA, 1B) et le répartiteur de coulée (3) sous lequel elle doit être placée.13. Protective device according to one of claims 7 to 12, characterized in that it comprises at its upper part at least one annular seal (4) making it possible to seal between the shell (lA, 1B) and the tundish (3) under which it is to be placed. 14. Dispositif selon l'une des revendications 7 à 13, destiné à être accouplé à un répartiteur de coulée (3) autour de l'orifice de coulée de celui-ci, caractérisé en ce qu'il coopère avec une virole circulaire (5), solidaire du répartiteur (3) et destinée à améliorer l'étanchéité au gaz de l'accouplement.14. Device according to one of claims 7 to 13, intended to be coupled to a tundish (3) around the pouring orifice thereof, characterized in that it cooperates with a circular ferrule (5 ), integral with the distributor (3) and intended to improve the gas tightness of the coupling. 15. Dispositif selon l'une des revendications 7 à 14, caractérisé en ce que les moyens d'articulation (31) des demi-coquilles sont constitués par une charnière.15. Device according to one of claims 7 to 14, characterized in that the articulation means (31) of the half-shells are constituted by a hinge. 16. Dispositif selon l'une des revendications 7 à 15, caractérisé en ce que les moyens d'articulation (31) des demi-coquilles sont constitués par un ensemble de bras articulés (431, 435) permettant d'éloigner les demi-coquilles l'une de l'autre, lesdits bras articulés étant commandés par des moyens de ccmnande (421, 423, 426, 430, 432).16. Device according to one of claims 7 to 15, characterized in that the articulation means (31) of the half-shells consist of a set of articulated arms (431, 435) allowing the half-shells to be moved away one from the other, said articulated arms being controlled by control means (421, 423, 426, 430, 432). 17. Dispositif selon l'une des revendications 7 à 16, caractérisé en ce qu'il comporte un bras mobile (435) qui lui est solidaire à une extrémité (462) et relié à des moyens (436,450) pour plaquer ladite coquille (lA, 1B)contre le répartiteur (3).17. Device according to one of claims 7 to 16, characterized in that it comprises a movable arm (435) which is integral with it at one end (462) and connected to means (436,450) for pressing said shell (lA , 1B) against the distributor (3). 18. Dispositif selon l'une des revendications 7 à 17, caractérisé en ce que les moyens (lA, 1B) pour entourer le jet de coulée18. Device according to one of claims 7 to 17, characterized in that the means (lA, 1B) for surrounding the pouring jet (2) ont une longueur telle qu'ils entourent ledit jet sensiblement sur toute sa hauteur.(2) have a length such that they surround said jet substantially over its entire height. 19. Utilisation d'un dispositif selon l'une des revendications 7 à 19, pour la protection d'un jet de coulée issu d'une poche ou d'un répartiteur, caractérisé en ce que l'on sépare les demi-coquilles (lA, 1B), on amène les demi-coquilles de part et d'autre du jet de coulée (2), on ferme les demi-coquilles (lA, 1B), puis on plaque l'ensemble contre la poche ou le répartiteur (3), autour de l'orifice de coulée.19. Use of a device according to one of claims 7 to 19, for the protection of a casting jet from a ladle or a distributor, characterized in that the half-shells are separated ( lA, 1B), the half-shells are brought on either side of the casting jet (2), the half-shells are closed (lA, 1B), then the assembly is pressed against the ladle or the distributor ( 3), around the pouring orifice.
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 true EP0213042A2 (en) 1987-03-04
EP0213042A3 EP0213042A3 (en) 1988-12-07
EP0213042B1 EP0213042B1 (en) 1990-09-19

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

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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)

Cited By (1)

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FR2642678A1 (en) * 1989-02-07 1990-08-10 Air Liquide Process for producing a gaseous atmosphere in contact with a metal at high temperature

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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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US3439735A (en) * 1965-11-19 1969-04-22 Union Carbide Corp Continuous casting apparatus with inert gas protector
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.
FR2331402A1 (en) * 1975-11-12 1977-06-10 Linde Ag CASTING PLANT
DE2738587A1 (en) * 1976-08-30 1978-03-02 Georgetown Steel Corp SHIELDING DEVICE FOR A CASTING JET MADE OF LIQUID METAL
EP0089282A1 (en) * 1982-03-15 1983-09-21 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process and device for the protection of a casting stream of liquid metal

Cited By (1)

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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

Also Published As

Publication number Publication date
ATE56642T1 (en) 1990-10-15
AU6118286A (en) 1987-02-19
ZA866054B (en) 1987-03-25
EP0213042B1 (en) 1990-09-19
AU594354B2 (en) 1990-03-08
US4805688A (en) 1989-02-21
EP0213042A3 (en) 1988-12-07
PT83195B (en) 1992-10-30
ES2001086A6 (en) 1988-04-16
FR2586210B1 (en) 1988-05-13
KR870001888A (en) 1987-03-28
CA1299837C (en) 1992-05-05
BR8603875A (en) 1987-03-24
PT83195A (en) 1986-09-01
JPS6297759A (en) 1987-05-07
FR2586210A1 (en) 1987-02-20
DE3674293D1 (en) 1990-10-25

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