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EP 2 866 962 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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18.01.2017 Bulletin 2017/03 |
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Date of filing: 29.06.2012 |
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International Patent Classification (IPC):
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International application number: |
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PCT/IB2012/053317 |
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International publication number: |
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WO 2014/001848 (03.01.2014 Gazette 2014/01) |
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CRUCIBLE FOR A MACHINE FOR CONTINUOUSLY CASTING A BAR OR A COIL OF A METAL ALLOY
TIEGEL FÜR EINE MASCHINE ZUM STRANGGIESSEN EINER STANGE ODER EINER SPULE AUS EINER
METALLLEGIERUNG
CREUSET POUR UNE MACHINE POUR LE COULAGE EN CONTINU D'UNE BARRE OU D'UNE BOBINE D'UN
ALLIAGE MÉTALLIQUE
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Designated Contracting States: |
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AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL
NO PL PT RO RS SE SI SK SM TR |
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Date of publication of application: |
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06.05.2015 Bulletin 2015/19 |
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Proprietors: |
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- Le Bronze Industriel
51600 Suippes (FR)
- Rautomead Limited
Dundee, DD2 4UH (Scotland) (GB)
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Inventors: |
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- PRIMAUX, François
F - 51110 Isles sur Suippe (FR)
- COOPER, Mervyn
Glenfarg
Perthshire PH2 9QY (GB)
- BELL, Colin
Dundee DD1 4BT (GB)
- BROWN, Graeme
Tealing
Dundee DD4 0QY (GB)
- MARNIE, Gavin
Dundee DD4 6EB (GB)
- FRAME, Brian
Perth PH1 1LJ (GB)
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Representative: Rhein, Alain |
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Cabinet Bleger-Rhein-Poupon
4A, rue de l'Industrie 67450 Mundolsheim 67450 Mundolsheim (FR) |
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References cited: :
EP-A1- 0 142 139 DE-A1- 19 747 002
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EP-A1- 2 039 444 US-B2- 7 036 554
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The invention is related to the field of the manufacture of bars or coils through
continuous casting of copper alloy with additions of chromium, zirconium, or chromium
and zirconium which will be called the "material" in the present document. A particular
application of the "material" is the manufacture of welding electrodes.
[0002] The manufacture of this material traditionally occurs through casting of billets,
then through hot extrusion of these billets, and finally through cold drawing in order
to bring them to the final size. An operation of solution annealing, which consists
in bringing the alloy at a temperature at which the addition elements (Cr, Zr) have
their largest domain of solubility in copper, followed by a quenching in water, will
occur after hot extrusion. A precipitation or ageing treatment will be added, generally
after drawing, in order to provide the required mechanical and electrical properties.
[0003] EP 0 142 139 discloses a crucible for a machine for continuously casting a bar or a coil of a
metal alloy, including a casting chamber and a primary supply chamber for supplying
a molten metal alloy.
[0004] EP 2 039 444 discloses a process for manufacturing copper alloy wore rod.
[0005] US 7 036 554 discloses a method and system for casting metal and metal alloys.
[0006] DE 197 47 002 is related to a three-chamber magnesium melting furnace operating by stepwise temperature
increase of the melt, in the flow direction through the chambers.
[0007] EP1 649 950 provides a continuous casting solution in the manufacture of welding electrodes.
A solution is provided for achieving, directly at the exit of the continuous casting,
a wire that is sufficiently thin for being passed directly to the cold mill or drawing
bench, thus saving the hot extrusion phase.
[0008] Nevertheless, for some types of material these methods are not satisfactory. As soon
as an element highly reactive to oxygen in a hot atmosphere enters into the composition
of the alloy, said element becomes oxidized during the pouring from the melting furnace
into the casting furnace, and the final composition of the alloy does not contain
the required percentage of this element.
[0009] This is in particular the case for zirconium, which very quickly becomes oxidized
when it is in the liquid state in copper. Hence, when it is desired to obtain products
made of an alloy of copper, chromium and zirconium, the continuous casting method
described above does not work.
[0010] The present invention attempts to cope with at least part of the above-mentioned
drawbacks and provides a solution, which permits to obtain the material or any product
in form of bars and coils made of an alloy comprising an element highly reactive to
oxygen in a hot atmosphere, such as for example magnesium, calcium, lithium or titanium.
[0011] To this end, the invention relates to a crucible for a machine for continuously casting
a wire of a metal alloy, including a casting chamber, a primary supply chamber for
supplying a molten metal alloy and a channel for transferring said molten metal alloy
to the casting chamber.
[0012] This crucible is particular in that it includes, in addition, a secondary supply
chamber configured for supplying the machine with a secondary metal and connected
to the primary supply chamber through an interior opening arranged at the lower level
of said primary supply chamber, and configured so that, in operation, the separation
is complete at the level of the surface of said molten metal alloy in the primary
supply chamber.
[0013] Thanks to these features, it becomes possible, at the level of the secondary supply
chamber, to create an area in which the molten metal alloy is protected against the
air, and in which a mixing with an additional component highly sensitive to air at
high temperature, as for example zirconium, can thus be contemplated.
[0014] According to other features :
- said transfer channel may be arranged in front of the secondary supply chamber, thus
obliging the molten metal alloy to transit through the secondary supply chamber,
- said crucible can be made of graphite, thus allying the good strength in a hot atmosphere
of the graphite, insofar as there is no oxygen, and the tendency of the graphite to
draw the small quantity of oxygen that remains in the molten metal alloy, making the
latter even leaner in oxygen, and thus little reactive to the coming supply of secondary
metal.
[0015] The present invention also relates to a machine for continuously casting a bar or
coil made of metal alloy, comprising a crucible according to the invention, and a
casting furnace surrounding said crucible, said casting furnace containing, in addition,
heating elements made of graphite and a ceramic liner for protecting the top of the
crucible ; the heating elements made of graphite permit to heat the crucible for maintaining
the molten metal alloy at temperature until the casting, and the ceramic liner protects
the top of the crucible against oxidation through contact with the air.
[0016] According to other features :
- said liner may include a partition configured so as to separate the secondary supply
chamber from the primary supply chamber, thus providing a very practical solution
for the separation.
[0017] The present invention finally relates to a method for manufacturing a bar or coil
through continuously casting by means of a machine according to the invention, characterized
in that it comprises the following steps :
- supplying the primary alloy in the absence of oxygen in the primary supply chamber
of the crucible
- adding a secondary metal into said oxygen-free primary alloy in the secondary supply
chamber of the crucible
- casting through a casting die
[0018] According to other features :
- said method can comprise an additional step of mixing the secondary metal into the
primary alloy, in order to get an homogeneous composition, said mixing being made
through mechanical stirring, through the flow of the primary molten alloy supply,
through electromagnetic stirring, or any other method,
- said primary molten alloy supply can occur by means of a fore hearth of a melting
furnace that contains the liquid metal, which feeds a primary supply chamber of a
crucible, and is placed on a liner of said crucible so as to protect a primary supply
opening of said crucible from air ingress, thus proposing an effective and simple
method of protection,
- the supply of primary alloy into the primary supply chamber at the level of said fore
hearth can be regulated by acting on the opening and closing of a stopper, with respect
to a nozzle located above and preferably in the middle of the primary supply opening,
which provides the advantage of a robust and simple method, the preferred position
in the middle providing an ideal flow configuration,
- the opening/closing of the stopper can be actuated depending on a level sensor and
depending on the turbulence one wants to create in the primary and/or a secondary
supply chambers, the level sensor giving the information when primary alloy needs
to be supplied or not, and the turbulence being requested stronger when the degree
of homogeneity needs to be increased,
- said secondary metal can be added into a secondary supply chamber, in order to get
a type of flow and mixing that results in a good homogeneity of the resulting alloy
for the casting step,
- said secondary metal can be added in the pure solid form or in the form of a mother
alloy, preferably in the form of powder, preferably inside a tube made of the same
material as the primary alloy or as the basic element of the primary alloy, the supply
speed of which can be adjusted, thus permitting same to be immersed into the molten
metal alloy bath and protected against the air before being at high temperature,
- said supply of primary alloy can occur in a protective atmosphere by adding a protective
gas, thus avoiding that said molten alloy becomes loaded with oxygen,
- said primary alloy can be copper alloy or a copper-chromium alloy, and said secondary
metal can contain zirconium, thus permitting the casting of a bar or coil made of
CuZr or CuCrZr alloy, adapted for example for the production of spot-welding electrodes.
[0019] The advantage deriving from the present invention consists in the fact that the additional
component highly sensitive to air, like zirconium, is introduced into an oxygen-free
molten metal. It is thus preserved in its entirety for forming the finally casted
alloy, which permits to control the zirconium content of the alloy, while minimizing
the consumption of this metal.
[0020] Further features and advantages of the invention will become clear from the following
detailed description, which refers to one exemplary embodiment, which is given by
way of an indication and is non-restrictive.
[0021] The understanding of this description will be facilitated when referring to the attached
drawings, in which :
- figure 1 represents a cross-section of a device according to the invention
- figure 2 represents a view from above of the device of fig. 1 ;
- figure 3 represents the cross-section BB of the device of fig.2 ;
- figure 4 represents a partial cross-sectional view of a fore hearth of a melting furnace
- figure 5 represents a view from above of a crucible according to the invention ;
- figure 6 represents the cross section CC of the device of fig. 2 according to a first
embodiment of the invention ;
- figure 7 represents the cross section CC of the device of fig. 2 according to a second
embodiment of the invention.
[0022] As shown in figures 1 to 7 of the attached drawing, the present invention relates
to a machine 1 for continuous casting. The machine 1 is described hereafter with respect
to a manufacture of electrodes made of an alloy of copper, chromium and zirconium.
The specialist in the art will easily be able to adapt the solution to other alloys
comprising an element highly reactive to oxygen in a hot atmosphere. This machine
1 includes a crucible 7, with a casting chamber 2 provided with a continuous casting
die 3, shown when casting upwards. The invention also encompasses the machines 1 with
a different number of dies 3, as well as with horizontal or downward casting dies
3, and it is easy for a specialist in the art to adapt it to this case.
[0023] The crucible 7 also includes a primary supply chamber 4 configured for supplying
the machine 1 with molten metal alloy, in particular copper and chromium. It includes,
in addition, a secondary supply chamber 5 configured for supplying the machine 1 with
an alloying metal, in particular zirconium. A transfer channel 6 is arranged between
the secondary supply chamber 5 and the casting chamber 2 at a level normally covered
with liquid metal in operation, said channel 6 permitting that the molten metal passes
from the secondary supply chamber 5 to the casting chamber 2, or exceptionally comes
back from same, for example during a stoppage of the casting in order to absorb an
expansion of the molten metal.
[0024] The crucible 7 is made of graphite. This material has a first advantage, which is
that it withstands high temperatures, in the range of 2000°C, at which the molten
metal is present. Nevertheless, at these temperatures it becomes quickly oxidized
in the presence of oxygen. A ceramic liner 8 has therefore been arranged on the top
of the crucible 7, in order to protect it against room air. Ceramic is a good choice
for such a liner because it withstands high temperatures and effectively protects
the graphite of the crucible from the oxygen of the air ; however other materials
can also be used. This liner 8 can advantageously completely close the casting and
supply chambers 2, 4, 5, while leaving only openings 12 necessary for the dies 3,
on the one hand, and 13, 14 for the supply, on the other hand of molten metal and
alloying metal. In addition, this liner 8 may comprise a partition 11 (see fig. 7)
for separating the primary supply chamber 4 from the secondary supply chamber 5. The
liner 8 may alternatively not have such a partition 11, and the separation of the
primary supply chamber 4 from the secondary supply chamber 5 is then made by a wall
of the crucible 7 itself (see fig. 6). An interior opening 21 is provided in both
cases, providing a passage between both chambers. The crucible 7 is furthermore placed
in a casting furnace 9 provided with heating elements 10 made of graphite. These heating
elements 10 are configured to heat the crucible 7 through radiation. They are in turn
heated by the passing through of a current and by joule effect. The complete casting
furnace 9 is filled with a protective gas, for example nitrogen, which permits to
protect both the heating elements 10 and the outside of the crucible 7 against room
air, and thus to avoid their accelerated oxidizing.
[0025] The inside of the crucible 7, forming the casting and supply chambers 2, 4, 5, is
protected against the oxygen by the presence of the molten metal.
[0026] In addition, one tries, within the scope of the present invention, to protect the
zirconium present in the molten metal against the oxygen. Hereafter will be described
the measures aimed at minimizing the presence of oxygen in the molten metal. It is
however not possible to completely eliminate the presence of oxygen. Now, graphite
is highly reactive to oxygen at the temperatures involved. The graphite of the crucible
7 will thus draw and entrap the oxygen still present in the molten metal, which further
reduces the quantity of oxygen likely to oxidize the zirconium.
[0027] The supply of molten copper and chromium alloy occurs through the primary supply
opening 13 of the liner 8 towards the primary supply chamber 4. The copper and the
chromium are melted in a melting furnace 20 (figure 4), in which they are subjected
to heating and magnetic stirring according to known methods.
[0028] The melting furnace 20 is designed with a fore hearth 15 for transferring the molten
copper-chromium alloy to the primary supply chamber 4, through the primary supply
opening 13. The form of the fore hearth 15 and the primary supply opening 13 is such
that, during operation, the primary supply opening 13 is « closed » by the fore hearth
15 of the melting furnace 20. The transfer occurs in a nitrogen atmosphere, injected
into the primary supply chamber 4, in order to avoid any contact of the liquid alloy
with oxygen, and to thus minimize the quantity of oxygen contained in the liquid alloy
inside the primary supply chamber 4.
[0029] The molten metal alloy flows towards the secondary supply chamber 5, passing through
the interior opening 21 under the liner partition 11 when present, the surface of
the melt in this secondary supply chamber 5 is protected from air with a graphite
powder layer.
[0030] Solid zirconium is simultaneously introduced through the secondary supply opening
14 into the secondary supply chamber 5. The zirconium is heated and melts very quickly,
through the conjunction of its low specific heat and its small mass percentage in
the alloy. Once it is liquid, the zirconium disperses in the liquid, due to the movements
induced by the supply into the two supply chambers 4, 5 and the transfer of the molten
alloy through the transfer channel 6. One can also choose to add another mixing means,
like a mechanical stirring means, or an electromagnetic stirring means.
[0031] According to the accuracy sought as regards the zirconium content of the alloy, zirconium
can be introduced by means of a Cu 50% Zr 50% alloy in the form of more or less small
particles, and even in the form of powder in a copper alloying tube 19. According
to a particular embodiment, the supply of liquid copper-chromium alloy is regulated
through the opening-closing action of a stopper 16 on a nozzle 17 located at the bottom
of the fore hearth 15. The opening is actuated when the level sensor 18 arranged in
a supply chamber 4, 5 indicates a predetermined low level, the closing is actuated
when the level sensor 18 indicates a predetermined high level. The zirconium supply
occurs in the secondary chamber 5 in the form of zirconium powder, according to a
flow rate adapted to the supply of molten metal alloy into the primary supply chamber
4.
[0032] There can be another level sensor in the casting chamber 2, intended to control the
level of molten alloy at the continuous casting die 3. The machine 1 can be configured
vertically mobile, in order to allow adjustments so as to guarantee a constant level
at said die.
[0033] The advantage of the present invention is that the shape of the liner 8, the primary
supply opening 13, the fore hearth 15, the stopper 16 and the nozzle 17 are configured
so that in the situation of production:
- the fore hearth 15 is placed on the liner 8 and obstructs the primary supply opening
13, making easy the inerting with nitrogen of the free space of the primary supply
chamber 4 above the molten metal alloy.
- The supply into the primary supply chamber 4 occurs by opening the stopper 16, which
lets the liquid metal pass from the fore hearth 15 through the nozzle 17, this supply
can occur continuously or discontinuously by opening, then closing the stopper 16.
[0034] The advantage deriving from the present invention resides in particular in that the
zirconium is introduced into an oxygen-free molten metal. It is thus preserved to
a maximum for forming the finally casted alloy, which permits to control the zirconium
content of the alloy, while minimizing the consumption of this metal.
[0035] In order to control the melting and the mixing of Zr into the basic alloy, it can
be easier to introduce the Zr as deep as possible into the secondary supply chamber
5, and to perform a strong stirring in order to melt and mix very well the Zr. In
case Zr is in the form of powder in a copper tube 19, the more it is desired that
the Zr be released at the bottom of the secondary supply chamber 5, the more the speed
of introduction of the copper alloying tube 19 should be increased, so that the copper
wall of the tube 19 melts later and releases the Zr deeper. It is possible that by
acting in this way more Zr than necessary is introduced, then the copper alloying
tube 19 will have to be removed and the supply of Zr will have to be discontinuous.
[0036] In order to improve the stirring in the secondary supply chamber 5 and to accelerate
the melting and mixing of the Zr, it can be useful to increase the flow rate of the
supply towards the primary supply chamber 4 beyond the flow rate of extraction by
the casting dies 3, this will create a turbulence in the primary and secondary supply
chambers 4, 5, but will also cause the level of the liquid metal in the whole crucible
7 to rise. It will be necessary to reduce, even stop the supply towards the primary
supply chamber 4 by acting on the closing of the stopper 16.
[0037] Although the invention has been described with respect to a particular embodiment,
it is understood that it is in no way restricted thereto and that various modifications
of shapes, materials and combinations of these various elements can be made without
departing from the framework of the invention.
1. Crucible (7) for a machine (1) for continuously casting a bar or coil of a metal alloy,
including a casting chamber (2), a primary supply chamber (4) for supplying a molten
metal alloy, characterized in that it includes a transfer channel (6), for transferring said molten metal alloy to the
casting chamber (2), and it includes in addition a secondary supply chamber (5) configured
for supplying the machine (1) with a secondary metal and connected to the primary
supply chamber (4) through an interior opening (21) arranged at the lower level of
said primary supply chamber (4), and configured so that, in operation, the separation
is complete at the level of the surface of said molten metal alloy in the primary
supply chamber (4) .
2. Crucible (7) according to the preceding claim, wherein said transfer channel (6) is
arranged in front of the secondary supply chamber (5), between the secondary supply
chamber (5) and the casting chamber (2) at a level normally covered with liquid metal
in operation, said channel (6) permitting that the molten metal passes from the secondary
supply chamber (5) to the casting chamber (2).
3. Crucible (7) according to any of the preceding claims, made of graphite.
4. Machine (1) for continuously casting a bar or coil of a metal alloy, comprising a
crucible (7) according to one of the preceding claims, and a casting furnace surrounding
said crucible (7), said casting furnace (9) containing, in addition, heating elements
(10) made of graphite and a ceramic liner (8) for protecting the top of the crucible
(7).
5. Machine (1) according to the preceding claim, wherein said liner (8) includes a liner
partition (11) configured to separate the secondary supply chamber (5) from the primary
supply chamber (4).
6. Method for manufacturing a bar or coil through continuously casting by means of a
machine (1) according to one of claims 4 or 5,
characterized in that it comprises the following steps:
- supplying a molten metal alloy in the absence of oxygen in the primary supply chamber
(4) of the crucible (7)
- adding a secondary metal into said oxygen-free primary alloy in the secondary supply
chamber (5) of the crucible (7)
- casting through a casting die (3).
7. Method according to claim 6 which comprises an additional step of mixing the secondary
metal into the primary alloy
8. Method according to one of the two preceding claims, wherein said molten metal alloy
supply occurs by means of a fore hearth (15) of a melting furnace (20) that contains
the molten metal alloy, said fore hearth (15) feeding a primary supply chamber (4)
of a crucible (7), and being placed on a liner (8) of said crucible (7) so as to protect
a primary supply opening (13) of said crucible (7) from air ingress.
9. Method according to the preceding claim, wherein the supply of molten metal alloy
into the primary supply chamber (4) at the level of said fore hearth (15) is regulated
by acting on the opening and closing of a stopper (16), with respect to a nozzle (17)
located above and in the middle of the primary supply opening (13).
10. Method according to the preceding claim, wherein the opening/closing of the stopper
(16) is actuated depending on a level sensor (18) and depending on the turbulence
one wants to create in the primary and/or a secondary supply chambers (4,5).
11. Method according to one of the claims 6 to 10, wherein said secondary metal is added
in the pure solid form or in the form of a mother alloy, in the form of powder, inside
a copper alloying tube (19) the supply speed of which can be adjusted.
12. Method according to one of the claims 6 to 12, wherein said molten metal alloy supply
occurs in a protective atmosphere by adding a protective gas.
13. Method according to one of claims 6 to 13 wherein said molten metal alloy is a copper-chromium
alloy, and said secondary metal contains zirconium.
1. Tiegel (7) für eine Maschine (1) zum Stranggießen einer Stange oder Spule einer Metalllegierung,
umfassend eine Gießkammer (2), eine primäre Zufuhrkammer (4) zum Zuführen einer Metalllegierungsschmelze,
dadurch gekennzeichnet, dass er einen Überführungskanal (6) umfasst, um die Metallegierungsschmelze in die Gießkammer
(2) zu überführen, und dass er zusätzlich eine sekundäre Zufuhrkammer (5) umfasst,
die konfiguriert ist, um die Maschine (1) mit einem Sekundärmetall zu speisen, und
über eine innere Öffnung (21), die im unteren Bereich der besagten primären Zufuhrkammer
(4) angeordnet ist, mit der primären Zufuhrkammer (4) verbunden und so konfiguriert
ist, dass im Betrieb die Trennung im Bereich der Oberfläche der besagten Metallegierungsschmelze
in der primären Zufuhrkammer (4) vollständig ist.
2. Tiegel (7) nach dem vorhergehenden Anspruch, bei dem der besagte Überführungskanal
(6) gegenüber der sekundären Zufuhrkammer (5), zwischen der sekundären Zufuhrkammer
(5) und der Gießkammer (2) auf einer Höhe angeordnet ist, die im Betrieb normalerweise
mit flüssigem Metall bedeckt ist, wobei der besagte Kanal (6) erlaubt, dass die Metallschmelze
von der sekundären Zufuhrkammer (5) in die Gießkammer (2) gelangt.
3. Tiegel (7) nach irgendeinem der vorhergehenden Ansprüche, der aus Graphit gefertigt
ist.
4. Maschine (1) zum Stranggießen eines Stabes oder einer Spule einer Metalllegierung,
umfassend einen Tiegel (7) nach einem der vorhergehenden Ansprüche und einen Gießofen,
der den besagten Tiegel (7) umgibt, wobei der besagte Gießofen (9) außerdem Heizelemente
(10) aus Graphit und eine Keramikauskleidung (8) zum Schützen des oberen Teils des
Tiegels (7) enthält.
5. Maschine (1) nach dem vorhergehenden Anspruch, bei der die besagte Auskleidung (8)
eine Auskleidungs-Trennwand (11) umfasst, die konfiguriert ist, um die sekundäre Zufuhrkammer
(5) von der primären Zufuhrkammer (4) zu trennen.
6. Verfahren zur Herstellung einer Stange oder Spule durch Stranggießen mittels einer
Maschine (1) nach einem der Ansprüche 4 oder 5,
dadurch gekennzeichnet, dass es die folgenden Schritte umfasst:
- Zuführen einer Metallegierungsschmelze in Abwesenheit von Sauerstoff in die primäre
Zuführkammer (4) des Tiegels (7),
- Zugeben eines Sekundärmetalls in die besagte sauerstofffreie Primärlegierung in
der sekundären Zufuhrkammer (5) des Tiegels (7),
- Gießen durch eine Gießdüse (3).
7. Verfahren nach Anspruch 6, das einen zusätzlichen Schritt der Zumischung des Sekundärmetalls
in die Primärlegierung umfasst.
8. Verfahren nach einem der beiden vorhergehenden Ansprüche, bei dem die besagte Zuführung
der Metalllegierungsschmelze mittels eines vorderen Herdes (15) eines Schmelzofens
(20) erfolgt, der die Metalllegierungsschmelze enthält, wobei der besagte vordere
Herd (15) eine primäre Zufuhrkammer (4) eines Tiegels (7) speist und auf einer Auskleidung
(8) des besagten Tiegels (7) angeordnet ist, sodass eine primäre Zufuhröffnung (13)
des besagten Tiegels vor Lufteintritt geschützt wird (7).
9. Verfahren nach dem vorhergehenden Anspruch, bei dem die Zufuhr von Metalllegierungsschmelze
in die primäre Zufuhrkammer (4) im Bereich des besagten vorderen Herdes (15) durch
Einwirkung auf das Öffnen und Schließen eines Stopfens (16) in Bezug auf eine oberhalb
und in der Mitte der primären Zufuhröffnung (13) angeordnete Düse (17) reguliert wird.
10. Verfahren nach dem vorhergehenden Anspruch, bei dem das Öffnen/Schließen des Stopfens
(16) in Abhängigkeit von einem Füllstandssensor (18) und in Abhängigkeit von der Verwirbelung,
die man in der Primär- und/oder einer Sekundärkammer (4, 5) schaffen wünscht, betätigt
wird.
11. Verfahren nach einem der Ansprüche 6 bis 10, bei dem das besagte Sekundärmetall in
reiner Feststoffform oder in der Form einer Mutterlegierung, in der Form eines Pulvers
innerhalb eines Kupferlegierungsrohrs (19), dessen Zufuhrgeschwindigkeit eingestellt
werden kann, zugegeben wird.
12. Verfahren nach einem der Ansprüche 6 bis 12, bei dem die besagte Zufuhr der Metalllegierungsschmelze
in einer Schutzatmosphäre durch Zugabe eines Schutzgases erfolgt.
13. Verfahren nach einem der Ansprüche 6 bis 13, bei dem die besagte Metalllegierungsschmelze
eine Kupfer-Chrom-Legierung ist und das besagte Sekundärmetall Zirkonium enthält.
1. Creuset (7) pour une machine (1) de coulée en continu d'une barre ou d'une bobine
d'un alliage métallique, comportant une chambre de coulée (2), une chambre d'alimentation
primaire (4) destinée à alimenter un alliage de métal en fusion, caractérisé par le fait qu'il comporte un canal de transfert (6) destiné à transférer ledit alliage de métal
en fusion vers la chambre de coulée (2) et qu'il comporte en outre une chambre d'alimentation
secondaire (5) configurée pour alimenter la machine (1) en métal secondaire et connectée
à la chambre d'alimentation primaire (4) par une ouverture intérieure (21) disposée
au niveau inférieur de ladite chambre d'alimentation primaire (4) et configurée de
sorte que, en fonctionnement, la séparation soit complète au niveau de la surface
dudit alliage de métal en fusion dans la chambre d'alimentation primaire (4).
2. Creuset (7) selon la revendication précédente, dans lequel ledit canal de transfert
(6) est disposé face à la chambre d'alimentation secondaire (5), entre la chambre
d'alimentation secondaire (5) et la chambre de coulée (2) à un niveau normalement
recouvert de métal liquide en fonctionnement, ledit canal (6) permettant au métal
en fusion de passer de la chambre d'alimentation secondaire (5) à la chambre de coulée
(2).
3. Creuset (7) selon l'une quelconque des revendications précédentes, réalisé en graphite.
4. Machine (1) de coulée en continu d'une barre ou d'une bobine en alliage de métal,
comprenant un creuset (7) selon l'une des revendications précédentes, et un four de
coulée entourant ledit creuset (7), ledit four de coulée (9) contenant, en outre,
des éléments chauffants (10) réalisés en graphite et un revêtement céramique (8) destiné
à protéger la partie supérieure du creuset (7).
5. Machine (1) selon la revendication précédente, dans laquelle ledit revêtement (8)
comporte une cloison de revêtement (11) configurée pour séparer la chambre d'alimentation
secondaire (5) de la chambre d'alimentation primaire (4).
6. Procédé de fabrication d'une barre ou d'une bobine par coulée en continu au moyen
d'une machine (1) selon l'une des revendications 4 ou 5,
caractérisé par le fait qu'il comprend les étapes suivantes consistant à:
- alimenter un alliage de métal en fusion en l'absence d'oxygène vers la chambre d'alimentation
primaire (4) du creuset (7),
- ajouter un métal secondaire dans ledit alliage primaire exempt d'oxygène dans la
chambre d'alimentation secondaire (5) du creuset (7),
- couler à travers une filière de coulée (3).
7. Procédé selon la revendication 6, qui comprend une étape additionnelle consistant
à mélanger le métal secondaire dans l'alliage primaire.
8. Procédé selon l'une des deux revendications précédentes, dans lequel l'alimentation
d'alliage de métal en fusion a lieu au moyen d'un foyer avant (15) d'un four de fusion
(20) qui contient l'alliage de métal en fusion, ledit foyer avant (15) alimentant
une chambre d'alimentation primaire (4) d'un creuset (7) et étant placé sur un revêtement
(8) dudit creuset (7) de manière à protéger une ouverture d'alimentation primaire
(13) dudit creuset (7) contre l'entrée d'air.
9. Procédé selon la revendication précédente, dans lequel l'alimentation d'alliage de
métal en fusion vers la chambre d'alimentation primaire (4) au niveau dudit foyer
avant (15) est régulée en agissant sur l'ouverture et la fermeture d'un bouchon (16),
par rapport à une buse (17) située au-dessus et au centre de l'ouverture d'alimentation
primaire (13).
10. Procédé selon la revendication précédente, dans lequel l'ouverture/fermeture du bouchon
(16) est actionnée en fonction d'un capteur de niveau (18) et en fonction de la turbulence
que l'on souhaite créer dans les chambres d'alimentation primaire et/ou secondaire
(4, 5).
11. Procédé selon l'une des revendications 6 à 10, dans lequel ledit métal secondaire
est ajouté sous forme solide pure ou sous forme d'un alliage mère, sous forme de poudre,
dans un tube d'alliage de cuivre (19) dont la vitesse d'alimentation peut être ajustée.
12. Procédé selon l'une des revendications 6 à 12, dans lequel ladite alimentation d'alliage
de métal en fusion a lieu dans une atmosphère protectrice en ajoutant un gaz protecteur.
13. Procédé selon l'une des revendications 6 à 13, dans lequel ledit alliage de métal
en fusion est un alliage de cuivre et de chrome, et ledit métal secondaire contient
du zirconium.
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only.
It does not form part of the European patent document. Even though great care has
been taken in compiling the references, errors or omissions cannot be excluded and
the EPO disclaims all liability in this regard.
Patent documents cited in the description