Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
  • B22D41/50—Pouring-nozzles
  • B22D41/58—Pouring-nozzles with gas injecting means

Definitions

• Refractory component and assembly with improved sealing for injection of an inert gas Refractory component and assembly with improved sealing for injection of an inert gas.
• the present invention relates to a refractory component used in the processing of a metal in the molten state, for example steel, fitted with a gas supply and providing improved sealing.
• the invention relates to such a component used in continuous casting of a metal in the molten state.
• casting of a liquid metal is generally carried out by means of an installation comprising various refractory components forming a channel between two successive metallurgical vessels. These refractory components perform various functions, namely conveyance of the liquid metal, protection of the liquid metal against cooling and chemical attack from the surrounding atmosphere and, where appropriate, regulation of the rate of pouring of the liquid metal.
• These components may be, for example, an inner nozzle supported on a well block integral with the bottom of the upper metallurgical vessel, a submerged entry nozzle or a pouring shroud, a collector nozzle, or the fixed or mobile plates of a slide valve.
• the joint surfaces between these various components forming a pouring channel all constitute points of potential ingress for the ambient air. In effect, by virtue of the flow of liquid metal through the pouring channel, substantial negative pressure is generated which is conducive to air ingress through these joint surfaces. The detrimental effects of such air ingress (nitrogen and oxygen) on the quality of the cast metal are known, and efforts have been made over a long period of time to remedy this.
• One of the known solutions in the current state of the art involves injecting an inert gas, for example argon, into the joint surface between two adjacent refractory components in the pouring channel.
• This injection may be effected for example via a groove made for this purpose in the surface of at least one of the components.
• this groove must as far as possible encircle the pouring orifice so that the inert gas which is under positive pressure can prevent any ingress of air into the pouring channel.
• an inert gas is injected directly into the pouring channel in a manner such that the inert gas cooperates mechanically with the liquid metal.
• the purpose of this type of inert gas injection may be to protect against erosion of certain refractory components located downstream of the injection point and which are particularly susceptible to the erosive action of the stream of liquid metal, such as for example the edges of the pouring orifice of the mobile plate of a slide valve designed to regulate the rate of flow.
• Another known effect of injecting an inert gas into a pouring channel is that it reduces problems of clogging of the pouring channel.
• the invention also relates to components used for the injection of gas into the bottom of a metallurgical vessel containing a bath of metal in the molten state, such as for example porous plugs.
• injection of gas will therefore refer both to the direct injection of an inert gas into a pouring channel or into the bottom of a metallurgical vessel and to the injection of an inert gas (or a sealing agent in suspension in a carrier fluid as described in international patent application
• WO 98/ 17421 into the joint surface between two adjacent refractory components of a pouring channel via a groove encircling at least partially the pouring orifice of the liquid metal, or to the injection of a cooling gas.
• the refractory components designed for the injection of an inert gas generally include means of delivering the gas to the means of injection (via a groove or the pouring channel).
• assemblies of refractory components are known in which the means of delivery and means of injection of the gas are provided by adjacent inter- communicating components (possibly they may even be separated by intermediate refractory components, the essential feature being that the gas can be transferred from the means of delivery to the means of injection) .
• the means of delivery generally include an inlet aperture opening on the outside wall of the refractory component and connected to a gas delivery line.
• This delivery line is connected to the fixed gas supply circuit of the casting installation, possibly via flexible pipes protected against thermal radiation.
• a metal connector is mounted in the inlet aperture; the connector and the material then form an integral assembly upon sintering of the constituent refractory material of the component.
• the connector can then be connected to the gas delivery line by screwing (either the connector is fitted with a male threaded part projecting beyond the component onto which the female end of the line is screwed, or the connector has a female thread into which the male-threaded end of the line is screwed), by welding or by various means of mechanical coupling.
• a refractory component provided with means of injecting or conveying gas and means of delivering said gas from an external wall of the component to said means of injection, the means of delivery of the gas comprising a part of enlarged cross-section extending from an external wall of the component and a part of reduced cross-section comrnunicating, at one end, with the inner end of the part of enlarged cross-section and, at the other end, with the means of injecting or conveying gas, the said component also comprising a seal fitted against the inner end of the part of enlarged cross-section, said seal, comprising an orifice at least partially in register with the commumcating orifice between the parts of enlarged and reduced cross-section is known from FR-A-2,763,012.
• the gas delivery line can be engaged more deeply into said component so that, when an appropriate seal is fitted therein, sealing tightness is assured not only at the cornmunication between the two parts of the means of delivery, but also at the walls of the part of enlarged cross-section.
• a very substantial improvement in sealing tightness compared with the device disclosed in European patent application 703,028 (reduction of the consumption of inert gas, reduction of air ingress, and precise control of the quantity of gas injected) was observed. However, it is desirable to still improve the sealing tightness.
• the seal presents a cross-section substantially similar to the cross- section of the enlarged part.
• the seal when the seal is placed in compression in an appropriate manner, it bears not only on the end of the part of enlarged cross-section, but also on the side walls of the latter, thereby providing an even tighter seal.
• the thickness of the seal does not exceed the depth of the part of enlarged cross-section, otherwise, under the effect of compression by the gas delivery line, the plastic seal will bear on the rim of the outer orifice of the means of delivery as it deforms, and sealing tightness will no longer be assured at the inner end of the part of enlarged cross-section.
• the inner end of the part of enlarged cross-section forms a surface presenting an orifice, the said parts of enlarged and reduced cross-section communicating via this orifice.
• a gas delivery line of essentially tubular form it is possible to use a gas delivery line of essentially tubular form.
• the part of enlarged cross- section consists of a bore of substantially circular cross-section which is easy to make.
• the thickness of the seal does not exceed the depth of the part of enlarged cross-section. It is to be noted that the seal can be made integral with the component.
• the seal presents a cross-section substantially similar to the cross-section of the enlarged part.
• the seal when the seal is placed in compression in an appropriate manner, it bears not only on the end of the part of enlarged cross-section, but also on the side walls of the latter, thereby providing an even tighter seal. It is essential that the thickness of the seal does not exceed the depth of the part of enlarged cross- section, otherwise, under the effect of compression by the gas delivery line, the plastic seal will bear on the rim of the outer orifice of the means of delivery as it deforms, and sealing tightness will no longer be assured at the inner end of the part of enlarged cross- section.
• the seal takes the form of a washer. Provision may be made however for a stack of such washers depending on the required thickness of the seal. The person skilled in the art will readily determine the optimal thickness of the seal.
• the seal is made of a plastic material so that, at operating temperatures, it is able to deform sufficiently when pressure is exerted on it to form a tight seal with the bottom wall and with the side walls of the end of the part of enlarged cross- section. Clay and graphite are materials potentially suitable for such use, graphite being the preferred choice.
• the invention relates to an assembly including a refractory component as described above and a gas delivery line, wherein one end of the gas delivery line is engaged in the part of enlarged cross-section which holds the seal in compression at the inner end and against the side walls of the part of enlarged cross- section.
• the refractory component is fitted with a metal casing (in the case of an inner nozzle for example) or band (in the case of a slide valve plate for example) covering it at least partially in the area of the gas delivery means. It is thus possible to form a solid attachment between the delivery line (by welding or screwing) and the casing or band, thereby avoiding accidental loss of sealing tightness in case of vibration for example.
• the end of the line engaged in the part of enlarged cross-section is configured so as to form a tight joint with the seal.
• the end may be shaped as a cone or truncated cone so that it "keys" into the joint.
• the end of the line may be threaded to enable the line to "screw” into the joint. Provision may also be made for a self-tapping end so that a perfectly fitting thread is formed in situ in the seal and the line/ seal joint is totally tight. According to this variant, it is advantageously the action of screwing the end of the line into the seal that compresses said seal towards the side walls of the part of enlarged cross-section.
• the part of enlarged cross-section is sufficiently deep so that, under the effect of thermal expansion of the end of the line engaged in the part of enlarged cross-section, the compression of the seal increases.
• the line is made solid with the casing or band, its only possibility of expansion is towards the end of the part of enlarged cross-section where the seal is located.
• FIG. 3 is an axial sectional view of a slide valve plate.
• Figure 1 shows an inner nozzle 1 comprising a refractory body 2 forming a pouring channel 3 and a plate 4.
• the inner nozzle 1 also includes means of injecting gas, for example an inert gas such as argon, into the pouring channel 3.
• These means of injecting gas are formed for example by a sleeve 5 in porous material mounted in a groove 6 formed in the refractory body 2.
• the groove 6 is connected to means of delivery of gas (7, 8) . As shown in figure 1, these means of delivery may emerge at the upper surface of the plate 4.
• Also shown is part of the gas delivery line 9, together with a metal casing 10 surrounding the plate 4 of the inner nozzle.
• Figure 2 shows the details of the connection between the gas inlet and the means of delivery of the gas at the plate 4 of the inner nozzle.
• These means of delivery of gas include a part of enlarged cross-section 7 and a part of reduced cross-section 8 corn ⁇ iunicating via an orifice 11.
• the inner end of the part of enlarged cross- section is fitted with a seal 12 for example in graphite.
• one end of the gas delivery line 9 engaged in the part of enlarged cross-section 7. It can be seen that the line 9 is made solid with the casing 10 by means of a circular weld 13.
• Figure 3 shows a refractory plate 14 of a slide valve presenting an orifice 15 for the pouring of metal.
• the plate is provided with a circular groove 16 circumscribing the pouring orifice 15 and forming with the surface of the refractory part (not shown) adjacent to the plate 14 a channel for the injection of a gas between these adjacent parts.
• the groove 16 is connected to gas delivery means including a portion of enlarged cross- section 17 and a portion of reduced cross- section 18 corriinunicating via an orifice 21.
• gas delivery line 19 engaged in the part of enlarged cross-section and made solid with the metal band 20 of the plate 14 by a spot weld 23.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
• Furnace Details (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)
• Furnace Housings, Linings, Walls, And Ceilings (AREA)
• Gasket Seals (AREA)

Priority Applications (1)

Applications Claiming Priority (4)

Publications (1)

Family

ID=8175739

Family Applications (1)

Country Status (16)

Families Citing this family (3)

Family Cites Families (7)

• 2001
  • 2001-04-23 AR ARP010101873A patent/AR028542A1/es not_active Application Discontinuation
  • 2001-04-24 TW TW090109756A patent/TW494139B/zh not_active IP Right Cessation
  • 2001-04-27 SK SK1516-2002A patent/SK15162002A3/sk unknown
  • 2001-04-27 MX MXPA02010599A patent/MXPA02010599A/es unknown
  • 2001-04-27 EP EP01929132A patent/EP1296787A1/en not_active Withdrawn
  • 2001-04-27 CA CA002406828A patent/CA2406828A1/en not_active Abandoned
  • 2001-04-27 PL PL01357772A patent/PL357772A1/xx not_active Application Discontinuation
  • 2001-04-27 CN CN01808578A patent/CN1444514A/zh active Pending
  • 2001-04-27 JP JP2001580008A patent/JP2003531728A/ja active Pending
  • 2001-04-27 KR KR1020027014219A patent/KR20030004368A/ko not_active Application Discontinuation
  • 2001-04-27 RU RU2002128609/02A patent/RU2002128609A/ru not_active Application Discontinuation
  • 2001-04-27 US US10/258,925 patent/US20030090043A1/en not_active Abandoned
  • 2001-04-27 WO PCT/BE2001/000076 patent/WO2001083138A1/en not_active Application Discontinuation
  • 2001-04-27 BR BR0110284-2A patent/BR0110284A/pt not_active Application Discontinuation
  • 2001-04-27 AU AU2001256017A patent/AU2001256017A1/en not_active Abandoned
• 2002
  • 2002-09-30 ZA ZA200207839A patent/ZA200207839B/en unknown

Non-Patent Citations (1)

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