EP0006453B1 - Process for increasing the lifetime of flush gas lances with porous lance heads made of graphite and inertion cage used therefor - Google Patents

Process for increasing the lifetime of flush gas lances with porous lance heads made of graphite and inertion cage used therefor Download PDF

Info

Publication number
EP0006453B1
EP0006453B1 EP79101605A EP79101605A EP0006453B1 EP 0006453 B1 EP0006453 B1 EP 0006453B1 EP 79101605 A EP79101605 A EP 79101605A EP 79101605 A EP79101605 A EP 79101605A EP 0006453 B1 EP0006453 B1 EP 0006453B1
Authority
EP
European Patent Office
Prior art keywords
graphite
lance
cage
gas
increasing
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.)
Expired
Application number
EP79101605A
Other languages
German (de)
French (fr)
Other versions
EP0006453A1 (en
Inventor
Werner Dr. Bücker
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.)
Messer Griesheim GmbH
Original Assignee
Messer Griesheim GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Messer Griesheim GmbH filed Critical Messer Griesheim GmbH
Publication of EP0006453A1 publication Critical patent/EP0006453A1/en
Application granted granted Critical
Publication of EP0006453B1 publication Critical patent/EP0006453B1/en
Expired legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
    • B22D1/002—Treatment with gases
    • B22D1/005—Injection assemblies therefor
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/05—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D1/00—Casings; Linings; Walls; Roofs
    • F27D1/16—Making or repairing linings increasing the durability of linings or breaking away linings
    • F27D1/1678—Increasing the durability of linings; Means for protecting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/16—Introducing a fluid jet or current into the charge
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/16—Introducing a fluid jet or current into the charge
    • F27D2003/168—Introducing a fluid jet or current into the charge through a lance
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D25/00—Devices or methods for removing incrustations, e.g. slag, metal deposits, dust; Devices or methods for preventing the adherence of slag

Definitions

  • the invention relates to a method and a device for increasing the service life of gas purging lances with porous purge heads made of graphite for non-ferrous metal melts.
  • the primary focus here is on aluminum melts that are flushed with argon.
  • the melt is cleaned, homogenized and degassed by flushing the molten metal with an inert gas. Rinsing is the last stage of treatment before the melt is poured.
  • the gas purging lance is lowered manually or mechanically into the crucible and the melt is flushed with an inert gas for about 5-10 minutes.
  • the rinsing treatment improves the quality of the castings by maintaining a dense structure and freedom from pores and also achieving good mold filling capacity.
  • the gas purging lances have flushing heads made of porous materials. Since the lances are exposed to the high temperatures of the metal melts, their lifespan is naturally short. This also applies to gas purging lances with flushing heads made of porous graphite, although graphite is a temperature-resistant material and the lance tube can also be made from graphite. The durability of graphite lances is nevertheless low, since the graphite burns out after use in the melt due to atmospheric oxygen.
  • the object of the invention is to increase the durability of such graphite lances by preventing the graphite from burning out after use in the melt.
  • a method has now been found for increasing the service life of gas purging lances with porous graphite purging heads for non-ferrous metal melts, in which, according to the invention, the lance immediately after purging in an inerting cage which surrounds the parts of the lance consisting of graphite with the formation of a gap with an inert gas until the ignition temperature of graphite falls below.
  • the inerting cage for carrying out the method according to the invention preferably consists of two half-shells which adapt to the shape of the parts of the lance made of graphite, forming a narrow gap.
  • the gap should be kept as narrow as possible, since then higher gas velocities are reached, which means that the lance cools down faster.
  • the half-shells can be connected to one another in an articulated manner by a hinge and can be designed to be lockable with one another in the folded state. This enables the lance to be inserted particularly quickly into the inerting cage after use in the melt.
  • the inerting cage is detachably installed on the bottle wagon on which the gas bottle with the purge gas is transported, so that a uniform implement is obtained.
  • FIG. 1 shows the flushing head 1 made of porous graphite of a gas flushing lance.
  • the flushing head 1 is attached to the lance tube 2, which is preferably also made of graphite.
  • the lance tube 2 is surrounded by an inerting cage, which consists of two half-shells 3, 4.
  • the half-shells 3, 4 are connected to one another in an articulated manner by a hinge 5.
  • a plate is welded onto the half-shell 3 and, when closed, represents the bottom of the cage.
  • the half-shells 3, 4 are shaped such that, when closed, they surround the flushing head 1 and the lance tube 2, forming a narrow gap 6, and thus form the inerting cage.
  • Fig. 2 shows the device in cross section.
  • FIG. 3 shows the device according to FIGS. 1 and 2 detachably installed on a bottle trolley 7 by means of a screw connection.
  • a second compressed gas bottle 9 is provided, which contains the nitrogen for cooling and inerting the lance.
  • the argon flows from the bottle 8 through the pressure reducer with flow meter 10, the compressed gas hose 11 and the lance tube 2 and the flushing head 1 into the molten metal, for example aluminum.
  • the gas purging lance has been used in the melt, it is quickly placed on the plate 12 and placed in the half-shell 3.
  • the half-shell 4 is folded onto the half-shell 3 and both half-shells are firmly connected to one another by means of the latch 132.
  • the argon supply is now interrupted and instead the nitrogen supply is released for cooling and inerting.
  • the nitrogen flows out of the compressed gas bottle 9 via the pressure reducer with flow meter 14 and the T-piece 15 into the compressed gas hose 11.
  • the flushing head 1 and the lance tube 2 quickly cooled by the high gas velocity in the narrow gap 6, so that the ignition temperature of graphite is soon fallen below.
  • the inert gas supply is interrupted and the lance can be safely removed from the inerting cage.
  • the inert gas consumption is low.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Description

Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur Erhöhung der Lebensdauer von Gasspüllanzen mit porösen Spülköpfen aus Grafit für Nichteisen-Metallschmelzen. Hierbei ist vor allem an Aluminiumschmelzen gedacht, die mit Argon gespült werden.The invention relates to a method and a device for increasing the service life of gas purging lances with porous purge heads made of graphite for non-ferrous metal melts. The primary focus here is on aluminum melts that are flushed with argon.

Durch das Spülen der Metallschmelze mit einem Inertgas wird die Schmelze gereinigt, homogenisiert und entgast. Das Spülen ist die letzte Behandlungsstufe vor dem Vergiessen der Schmelze. Die Gasspüllanze wird manuell oder mechanisch in den Tiegel gesenkt und die Schmelze etwa 5-10 Min. lang mit einem Inertgas gespült. Durch die Spülbehandlung wird die Qualität der Gussstücke verbessert, indem diese lich ein dichtes Gefüge und Porenfreiheit erhalten und ausserdem ein gutes Formfüllungsvermögen erreicht wird.The melt is cleaned, homogenized and degassed by flushing the molten metal with an inert gas. Rinsing is the last stage of treatment before the melt is poured. The gas purging lance is lowered manually or mechanically into the crucible and the melt is flushed with an inert gas for about 5-10 minutes. The rinsing treatment improves the quality of the castings by maintaining a dense structure and freedom from pores and also achieving good mold filling capacity.

Die Gasspüllanzen besitzen Spülköpfe aus porösen Materialien. Da die Lanzen den hohen Temperaturen der Metallschmelzen ausgesetzt werden, ist ihre Lebensdauer naturgemäss gering. Dies gilt auch für Gasspüllanzen mit Spülköpfen aus porösem Grafit, obwohl Grafit ein temperaturfester Werkstoff ist und auch das Lanzenrohr aus Grafit gefertigt werden kann. Die Haltbarkeit von Grafitlanzen ist aber dennoch gering, da der Grafit nach dem Einsatz in der Schmelze infolge des Luftsauerstoffs ausbrennt.The gas purging lances have flushing heads made of porous materials. Since the lances are exposed to the high temperatures of the metal melts, their lifespan is naturally short. This also applies to gas purging lances with flushing heads made of porous graphite, although graphite is a temperature-resistant material and the lance tube can also be made from graphite. The durability of graphite lances is nevertheless low, since the graphite burns out after use in the melt due to atmospheric oxygen.

Der Erfindung liegt die Aufgabe zugrunde, die Haltbarkeit derartiger Grafitlanzen zu vergrössern, indem das Ausbrennen des Grafits nach dem Einsatz in der Schmelze verhindert wird.The object of the invention is to increase the durability of such graphite lances by preventing the graphite from burning out after use in the melt.

Es wurde nun ein Verfahren zur Erhöhung der Lebensdauer von Gasspüllanzen mit porösen Spülköpfen aus Grafit für Nichteisen-Metallschmelzen gefunden, bei dem gemäss der Erfindung die Lanze unmittelbar nach dem Spülen in einem Inertisierungskäfig, der die aus Grafit bestehenden Teile der Lanze unter Ausbildung eines Spaltes umgibt, mit einem Inertgas solange durchströmt wird, bis die Zündtemperatur von Grafit unterschritten ist.A method has now been found for increasing the service life of gas purging lances with porous graphite purging heads for non-ferrous metal melts, in which, according to the invention, the lance immediately after purging in an inerting cage which surrounds the parts of the lance consisting of graphite with the formation of a gap with an inert gas until the ignition temperature of graphite falls below.

Als Inertgas zum Durchströmen der Lanze zwecks Kühlung wird Stickstoff bevorzugt. Der Inertisierungskäfig zur Durchführung des erfindungsgemässen Verfahrens besteht vorzugsweise aus zwei Halbschalen, die sich der Form der aus Grafit bestehenden Teile der Lanze unter Ausbildung eines engen Spaltes anpassen. Der Spalt soll dabei möglichst eng gehalten werden, da dann höhere Gasgeschwindigkeiten erreicht werden, wodurch sich die Lanze schneller abkühlt. Die Halbschalen können durch ein Scharnier gelenkig miteinander verbunden und im zusammengeklappten Zustand miteinander verriegelbar ausgeführt werden. Dies ermöglicht ein besonders schnelles Einlegen der Lanze in den Inertisierungskäfig nach dem Einsatz in der Schmelze. Bei einer vorteilhaften Ausführungsform der Erfindung wird der Inertisierungskäfig lösbar auf dem Flaschenwagen installiert, auf dem die Gasflasche mit dem Spülgas transportiert wird, so dass sich ein einheitliches Arbeitsgerät ergibt.Nitrogen is preferred as the inert gas for flowing through the lance for cooling. The inerting cage for carrying out the method according to the invention preferably consists of two half-shells which adapt to the shape of the parts of the lance made of graphite, forming a narrow gap. The gap should be kept as narrow as possible, since then higher gas velocities are reached, which means that the lance cools down faster. The half-shells can be connected to one another in an articulated manner by a hinge and can be designed to be lockable with one another in the folded state. This enables the lance to be inserted particularly quickly into the inerting cage after use in the melt. In an advantageous embodiment of the invention, the inerting cage is detachably installed on the bottle wagon on which the gas bottle with the purge gas is transported, so that a uniform implement is obtained.

Ein Ausführungsbeispiel der Erfindung soll anhand der beigefügten Zeichnungen erläutert werden.An embodiment of the invention will be explained with reference to the accompanying drawings.

Es zeigen:

  • Fig. 1 einen Schnitt durch einen Spülkopf und einen Teil des angeschlossenen Lanzenrohres, umgeben von einem Inertisierungskäfig,
  • Fig. einen Schnitt entlang der Linie A-A in Fig.1,
  • Fig.3 die Lanze mit Inertisierungskäfig nach den Fig. 1 und 2 auf einem Flaschenwagen installiert.
Show it:
  • 1 shows a section through a flushing head and part of the connected lance tube, surrounded by an inerting cage,
  • 1 shows a section along the line AA in FIG. 1,
  • 3 the lance with inerting cage according to FIGS. 1 and 2 installed on a bottle wagon.

Fig. 1 zeigt den Spülkopf 1 aus porösem Grafit einer Gasspüllanze. Der Spülkopf 1 ist auf dem Lanzenrohr 2 befestigt, welches vorzugsweise auch aus Grafit besteht. Erfindungsgemäss ist der Spülkopf 1 und das Lanzenrohr 2 von einem Inertisierungskäfig umgeben, der aus zwei Halbschalen 3, 4 besteht. Die Halbschalen 3, 4 sind durch ein Scharnier 5 gelenkig miteinander verbunden. An die Halbschale 3 ist ein Teller angeschweisst, der im geschlossenen Zustand den Boden des Käfigs darstellt. Die Halbschalen 3, 4 sind so geformt, dass sie im geschlossenen Zustand den Spülkopf 1 und das Lanzenrohr 2 unter Ausbildung eines engen Spaltes 6 umgeben und so den Inertisierungskäfig bilden. Fig. 2 zeigt die Vorrichtung im Querschnitt.1 shows the flushing head 1 made of porous graphite of a gas flushing lance. The flushing head 1 is attached to the lance tube 2, which is preferably also made of graphite. According to the flushing head 1 and the lance tube 2 is surrounded by an inerting cage, which consists of two half-shells 3, 4. The half-shells 3, 4 are connected to one another in an articulated manner by a hinge 5. A plate is welded onto the half-shell 3 and, when closed, represents the bottom of the cage. The half-shells 3, 4 are shaped such that, when closed, they surround the flushing head 1 and the lance tube 2, forming a narrow gap 6, and thus form the inerting cage. Fig. 2 shows the device in cross section.

Fig. 3 zeigt die Vorrichtung nach den Fig. 1 und 2 mittels einer Schraubverbindung lösbar installiert auf einem Flaschenwagen 7. Auf dem Flaschenwagen 76 ist die Druckgasflasche 8 befestigt, die das Spülgas für die Metallschmelze, beispielsweise Argon, enthält. Ferner ist eine zweite Druckgasflasche 9 vorgesehen, die den Stickstoff für die Kühlung und Inertisierung der Lanze enthält.3 shows the device according to FIGS. 1 and 2 detachably installed on a bottle trolley 7 by means of a screw connection. The pressure gas bottle 8, which contains the purge gas for the molten metal, for example argon, is fastened on the bottle trolley 76. Furthermore, a second compressed gas bottle 9 is provided, which contains the nitrogen for cooling and inerting the lance.

Im Betrieb strömt das Argon aus der Flasche 8 über den Druckminderer mit Durchflussmesser 10, den Druckgasschlauch 11 und das Lanzenrohr 2 und den Spülkopf 1 in die Metallschmelze, beispielsweise Aluminium. Nach dem Einsatz der Gasspüllanze in der Schmelze wird diese schnell auf den Teller 12 gestellt und in die Halbschale 3 eingelegt. Dann wird die Halbschale 4 auf die Halbschale 3 geklappt und beide Halbschalen werden mittels des Riegels 132 fest miteinander verbunden.In operation, the argon flows from the bottle 8 through the pressure reducer with flow meter 10, the compressed gas hose 11 and the lance tube 2 and the flushing head 1 into the molten metal, for example aluminum. After the gas purging lance has been used in the melt, it is quickly placed on the plate 12 and placed in the half-shell 3. Then the half-shell 4 is folded onto the half-shell 3 and both half-shells are firmly connected to one another by means of the latch 132.

Die Argonzufuhr wird nun unterbrochen und stattdessen die Stickstoffzufuhr zum Kühlen und Inertisieren freigegeben. Der Stickstoff strömt aus der Druckgasflasche 9 über den Druckminderer mit Durchflussmesser 14 und das T-Stück 15 in den Druckgasschlauch 11. Danach gelangt er aus dem Spülkopf 1 durch den engen Spalt 6 entlang des Lanzenrohres 2 nach aussen. Hierdurch wird der Zutritt von Luftsauerstoff zum Grafit und damit das Ausbrennen des Grafits verhindert. Gleichzeitig wird der Spülkopf 1 und das Lanzenrohr 2 durch die hohe Gasgeschwindikgeit im engen Spalt 6 schnell abgekühlt, so dass bald die Zündtemperatur von Grafit unterschritten wird. Dann wird die Inertgaszufuhr unterbrochen und die Lanze kann gefahrlos aus dem Inertisierungskäfig entnommen werden. Infolge der schnellen Abkühlung von Spülkopf 1 und Lanzenrohr 2 ist der Inertgasverbrauch gering.The argon supply is now interrupted and instead the nitrogen supply is released for cooling and inerting. The nitrogen flows out of the compressed gas bottle 9 via the pressure reducer with flow meter 14 and the T-piece 15 into the compressed gas hose 11. Then it comes out of the flushing head 1 through the narrow gap 6 along the lance tube 2 to the outside. This prevents the entry of atmospheric oxygen to the graphite and thus prevents the graphite from burning out. At the same time the flushing head 1 and the lance tube 2 quickly cooled by the high gas velocity in the narrow gap 6, so that the ignition temperature of graphite is soon fallen below. Then the inert gas supply is interrupted and the lance can be safely removed from the inerting cage. As a result of the rapid cooling of the flushing head 1 and lance tube 2, the inert gas consumption is low.

Claims (5)

1. Method for increasing the life of gas scavenging lances with porous scavenging heads of graphite characterised thereby that directly after the scavenging, an inert gas is passed through the lance in an inertisation cage (6), which surrounds the parts of the lange consisting of graphite with the formation of a gap, until the temperature is decreased to below the ignition temperature of graphite.
2. Method according to claim 1, characterized thereby that nitrogen is passed through the lance.
3. Inertisation cage for performing the method according to the claims 1 or 2, characterised thereby that it consists of two half shells (3, 4), which are adapted to the shape of the parts of the lance consisting of graphite with the formation of a narrow gap (6).
4. Inertisation cage according to claim 3, characterized thereby that the half shells (3, 4) are linked together by means of a hinge (5) and in the condition when closed together can be locked (13) together.
5. Inertisation cage according to claim 3 or 4, characterized thereby that it is removably installed on a cylinder transporter (7) on which the gas cylinder (8) with the scavenging gas is transported.
EP79101605A 1978-06-22 1979-05-25 Process for increasing the lifetime of flush gas lances with porous lance heads made of graphite and inertion cage used therefor Expired EP0006453B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2827403 1978-06-22
DE2827403A DE2827403C2 (en) 1978-06-22 1978-06-22 Device to increase the service life of gas primers with a porous graphite rinsing head

Publications (2)

Publication Number Publication Date
EP0006453A1 EP0006453A1 (en) 1980-01-09
EP0006453B1 true EP0006453B1 (en) 1981-06-03

Family

ID=6042463

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79101605A Expired EP0006453B1 (en) 1978-06-22 1979-05-25 Process for increasing the lifetime of flush gas lances with porous lance heads made of graphite and inertion cage used therefor

Country Status (7)

Country Link
US (1) US4264057A (en)
EP (1) EP0006453B1 (en)
JP (1) JPS552798A (en)
AT (1) AT377208B (en)
DE (1) DE2827403C2 (en)
ES (1) ES481712A1 (en)
ZA (1) ZA793085B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29818006U1 (en) * 1998-10-08 1999-03-11 Carbon Ind Produkte Gmbh Gas introduction system for melting baths

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU33708A1 (en) *
US3112194A (en) * 1960-10-19 1963-11-26 Union Carbide Corp Molten bath treating method and apparatus
US3304173A (en) * 1961-07-27 1967-02-14 United States Steel Corp Method of adding solids and oxygen to an open hearth furnace
NL296346A (en) * 1962-08-07
US3269829A (en) * 1963-09-24 1966-08-30 United States Steel Corp Method and apparatus for introducing steam and oxygen into a bath of molten steel
US3503597A (en) * 1967-02-20 1970-03-31 Kessler Harry Harvey Metal treating device
US3521874A (en) * 1967-05-12 1970-07-28 Reynolds Metals Co Gas diffuser unit for use in treating molten metal
US3932172A (en) * 1969-02-20 1976-01-13 Eisenwerk-Gesellschaft Maximilianshutte Mbh Method and converter for refining pig-iron into steel
FR2263308A1 (en) * 1974-03-08 1975-10-03 Combustible Nucleaire Purification of molten uranium to prevent axial fissures - occurring in continuous casting, by washing the melt with inert gas

Also Published As

Publication number Publication date
DE2827403B1 (en) 1979-08-02
AT377208B (en) 1985-02-25
EP0006453A1 (en) 1980-01-09
US4264057A (en) 1981-04-28
ZA793085B (en) 1980-08-27
JPS552798A (en) 1980-01-10
DE2827403C2 (en) 1980-04-03
ES481712A1 (en) 1980-02-16
ATA388479A (en) 1984-07-15

Similar Documents

Publication Publication Date Title
US4744821A (en) Process for producing spheroidal metal particles
DE1508113B1 (en) Method and device for lowering the manganese content of a steel or cast iron melt
EP0006453B1 (en) Process for increasing the lifetime of flush gas lances with porous lance heads made of graphite and inertion cage used therefor
DE60224977T2 (en) Preparation for welding process
CH625984A5 (en)
DE3200104C2 (en) Casting device for the production of alloyed metal castings
DE220035C (en)
DE2454776B2 (en) SYSTEM FOR INTRODUCING TREATMENT AGENTS IN METAL MELT
DE2263539A1 (en) Die casting melt filters - consisting of oxide bonded high temp refractory materials
US2950512A (en) Casting apparatus and method
DE2127936A1 (en) Device for forming a protective sheath around a molten metal stream
EP1149930A1 (en) Method and apparatus for regenerating a contaminated liquid metal bath
AT349666B (en) DEVICE FOR REPLACING IRON PIPES
DE3334989C2 (en) Process for producing low-oxygen metal powder
DE4332760A1 (en) Method for the operation of a low-pressure metal-casting apparatus and a low-pressure metal-casting apparatus for this purpose
DE664540C (en) Method and device for the production of dense castings using a gaseous pressure medium
AT162985B (en) Method and device for thermite welding
DE2227521C3 (en) Process for electroslag remelting of titanium or its alloys and apparatus for carrying out this process
DE2021491C (en) Metallic remelting electrode and device for its production
CH628547A5 (en) MOLD MOLDING METHOD AND DEVICE FOR POURING METALLIC MOLDING PIECES IN A MOLD.
DE2617237C3 (en) Lance head for the oxygen inflation process
DE3521086A1 (en) Process and apparatus for casting metal objects
DE2141176B2 (en) Method and device for treating molten metal, in particular for refining molten iron
DE62372C (en) Methods for cleaning up molten metal (iron)
AT340614B (en) DEVICE FOR ELECTRIC SLAG RE-MELTING OF CONSUMABLE ELECTRODES INTO HOLLOW BLOCKS

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): BE CH FR GB IT NL

17P Request for examination filed
ITF It: translation for a ep patent filed

Owner name: DE DOMINICIS & MAYER S.R.L.

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): BE CH FR GB IT NL

ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19920429

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19920511

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19920525

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19920531

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19920616

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19930525

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CH

Effective date: 19930531

Ref country code: BE

Effective date: 19930531

BERE Be: lapsed

Owner name: MESSER GRIESHEIM G.M.B.H.

Effective date: 19930531

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19931201

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19930525

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19940131

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT