WO2017036497A1 - Ceramic refractory stopper - Google Patents
Ceramic refractory stopper Download PDFInfo
- Publication number
- WO2017036497A1 WO2017036497A1 PCT/EP2015/069753 EP2015069753W WO2017036497A1 WO 2017036497 A1 WO2017036497 A1 WO 2017036497A1 EP 2015069753 W EP2015069753 W EP 2015069753W WO 2017036497 A1 WO2017036497 A1 WO 2017036497A1
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- WO
- WIPO (PCT)
- Prior art keywords
- stopper
- plug
- channel
- head
- refractory ceramic
- Prior art date
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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
- B22D41/14—Closures
- B22D41/16—Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening
- B22D41/18—Stopper-rods therefor
Definitions
- the invention relates to a ceramic refractory stopper (a stopper device ) for controll ing a flow of molten metal at an outlet opening of a metallurgical vessel, such as a tundi sh .
- the generic type of ceramic refractory stoppers compri ses a rod-shaped stopper body, one end secti on of which being designed for fixation to a corresponding lifting mechanism while the other end of which i s provi ded by the so call ed stopper head.
- the rod-shaped stopper body defines a centra! longitudinal axis.
- Stopper rods of this type have also being used to introduce a gas, such as an inert gas, i . a. argon, into the molten steel for removing non-metallic inclusions from the molten m elt.
- a gas such as an inert gas, i . a. argon
- the invention yet does not deal with such gas purging stoppers but exclusively foeusses on stoppers to control the melt (out)f!ow in a
- S uch generic stopper comprises
- the channel fulfils various tasks, i . a:
- a serious drawback of the channel is that air (oxygen) is sucked in and into the stopper head when the stopper is in use.
- a negative pressure may establish by the outfl owing metal stream around the stopper head.
- the air/oxygen may penetrate into the material/matrix of the stopper head and further leave the stopper head via its surface, penetrate into the metal melt and worsen the melt qual ity.
- Thi s is in particular a probl em in connection with the parallel demand for longer casting times, for example from 5h up to 24h.
- One maj or cognition of the invention is to prevent any air (oxygen) from being sucked into the channel via its first (upper) end and to continue (flow) into the stopper head .
- This option (I) has several drawbacks : it increases the material need and thus the costs ; it makes manufacturing of a monolithic (one-piece) generic stopper rod. much more difficult and it worsens the physical parameters of the stopper head, in particular its thermal shock behavior.
- the invention takes another way (II) . It keeps the channel design more or less unchanged but integrates a plug/barri er into the channel and - more prec isely - into the transition section of the channel between stopper body and stopper head.
- This barrier is selected to provide a gas permeabi lity as low as possible to stop the air flow on its way towards and into the stopper head at its best.
- the plug reduces or avoids any negative pressure and thus any suction o f air through the stopper head below this barrier (in its mounted position).
- This plug allows to realize further technical aspects, in particular it provides a mechanical reinforcement of the stopper in its lower section, being the one undergoing hi gh stresses and wear.
- the stopper head and the stopper body are further connected and stabilized by said intermediate and solid plug, protruding i nto the cavity (channel section) of the stopper head and into a corresponding (adj acent) channel section within the stopper body.
- This fixation may be achieved by a friction-fit arrangement (for example a slightly frustoconi cal shape of the plug;
- an adhesive for example a refractory binder
- reinforcement means like an anchor, fixed with one end in said plug and with another end in the stopper body or in the stopper head.
- a channel o f length L extending from a first end of said stopper body through said stopper body in a direction of said central longitudinal axis (A) towards the stopper head and into the stopper head, ending at a distance to the dome like outer surface, d) a plug, arranged within sai d channel over its whol e cross-section and extending with a first part into the channel within the stopper body and with a second end into the channel within the stopper head, wherein
- said plug has a gas permeabil ity smaller than 0,7 nPin .
- the gas permeability is defined in accordance with Routschka “Taschenbuch Feuerfeste Werkstoffe” Vulkan Verlag, 2001 , pages 397ff, [IS BN 3 - 8027- 3 1 50-6] .
- the plug extends to a depth into the stopper head leaving a terminal section of the channel unsealed : in. other words : The channel continues over a short distance below the fitted plug.
- the (typically blind) channel tapers between its first and second end.
- the sloping angle may be around 1 - 5°, for example 3 or 4 degrees. This al lows to optimize isostatic pressing of the stopper as the corresponding mandrel may easily be extracted after
- the channel may have any cross sectional profile but a circular cross section is of advantage for manufacturing and sealing the plug within the channel .
- the plug i tself may as well have a circular cross secti on, perpendicul ar to the central longitudinal axis of the stopper body.
- the plug may be of a substantially cylindrical or frustoconicai shape,
- the smaller end in the use position of the stopper should be the lower end. This makes the arrangement (substantially gas tight positioning) of the plug within the channel easier.
- cylindrical plug with a tapered lower end.
- the sloping angle of the plug may be in the same range as that for the channel or slightly smaller, which increases the respective friction and sealing effect between corresponding surfaces of plug and channel.
- Optional features of the plug are one or more of the following: its largest cross section, perpendicular to the central longitudinal axis, being slightly larger than the cross section of the blind channel at a corresponding position; this allow a friction-fit arrangement of the plug within the channel without further means its height, parallel to the central longitudinal axis (A), being larger than its largest width, perpendicular to the central longitudinal axis (A). Both design features improve the barrier effect of the plug within the channel.
- At least the stopper head is made of an MgO-C material.
- MgO-C material This has been proven favorable in conventional stoppers with the exception of reactions with air diffusing into the stopper head. As any air ingress is now avoided, the MgO-C material can be used without any drawbacks.
- a further safety feature not necessarily required but of advantage, especially when the stopper is intended to be used over long easting times, includes to use graphite (or another carbonaceous material to manufacture a plug of low gas permeability) as a material from which the plug is made.
- the graphite plug not only stops the oxygen flow but its carbon may react with said oxygen within the channel sections above said plug and thus consumes said oxygen.
- barrier means oxidic or non-oxidic refractory materials such as AI2O3, corundum, zircon, zirconia.
- the gas permeability of the plug should be as low as possible, in any case ⁇ 0,7 nPm, ⁇ 0,4 nPm ⁇ 0,2nPm, preferred ⁇ 0,1 nPm or ⁇ 0,05nPm.
- the gas permeability of the material for the stopper head may be higher, for example: l-2nPm (especially l,0-l,3nPra) in case of an A! 2 C>3-C-material or 1-2 (especially 1,1-1,4) in case of an MgO-C-material.
- the gas permeability is tested in accordance with DIN EN 993-4: 1995-04 at room temperature (20°C).
- Other optional parameters of the refractory ceramic stopper are;
- the plug has a thermal expansion coefficient a (20-1000°C)
- the plug is made of a material in a grain, fraction d9o ⁇ 64pm, often ⁇ 20 ⁇ ,
- the plug has a density (according to DIN 51918: 1999-08) of 1,5- 3,5g/cm 3 ,
- At least one of the stopper body, the stopper head and the plug is an isostatically pressed part
- the stopper body, the stopper head and the plug can also be pressed in-situ in an isostatic press.
- a favorable way to manufacture a stopper of the type described is to shape the stopper head in a hydraulic press, which allows an in-situ forming of the terminal end of the channel and which leads to increased densities in the refractory wall of the stopper head by squeezing. These densities can be higher than those of the stopper body. In other words; The stopper features higher densities in the stopper head at positions offset to the stopper body.
- hydraulically pressed stopper head or a cast stopper head may be combined with an isostatically pressed stopper body, while the plug can be manufactured by either way or machined out of a monolithic body.
- At least one of different interfaces between stopper body and plug, between stopper body and stopper head or between stopper head and plug can be covered with an adhesive (including a mortar) to glue adjacent surface section.
- the new stopper allows longer casting tim.es compared with prior art. It is expected that casting times of up 24h with one single stopper will become possible.
- the new design i s preferred in view of stoppers which provide a coated stopper head surface (WO 96/ 1 6758) as thi s coating undergoes severe wear during casting and l oses its function rapidly.
- Figure 1 shows a longitudinal sectional view of a first embodiment of the new stopper.
- Figure 2 displays an enlarged side view of the plug according to Fig. 1
- Figure 3 shows a longitudinal secti onal view of a second embodiment of the new stopper in the Figures identical structural elements or structural el ements of the same or similar function are referenced by the same numerals .
- Figures 1 ,2 The stopper compri ses a rod shaped stopper body 10, defining a central longitudinal axis A-A, and a stopper head 12 at a second end E2 of the stopper body 1 0, providing a dome like outer surface 12o, a blind channel 1 4 of length L, extending from a first end E l (upper surface l Ou) of said stopper body 1 0 through said stopper body 1 0 in a direction of said central
- a fitting F is arranged around channel 14 within stopper body 10 at its upper end El to allow mechanical connection to an associated (now shown) lifting mechanism.
- Said plug is arranged such that about 2/3 of its axial length (along A-A) protrude into channel part 14t above stopper head 10 and 1/3 protrudes into that section of channel 14 which extends into said stopper head 12.
- stopper body 10 dashed lines
- stopper head 12 crossed lines
- channel 14 tapers between ends El and £2 slightly (3°) while it tapers strongly along its terminal end section 14ts within stopper head 12 with a cross section close to zero at its lowermost end 14u.
- Plug 20 has a frustoconical shape as may be seen from Fig.2 with a sloping angle of 2,5° so that it fits perfectly within channel 14 and seals the channel 14 circumferentially against air ingress to any stopper sections below said plug 20.
- Plug 20 is made of a graphite material with a density of 1,8 g/cm 3 and has a gas permeability of 0,05 nPm. -li
- Stopper head 12 is made of a refractory MgO-C composition, while the stopper body is made of a conventional MgO material.
- Stopper body 10 and stopper head 12 are manufactured commonly in an iostatic press (mould).
- the corresponding mandrel has a general shape corresponding to that of channel 14.
- the plug 20 is fitted into the channel 14 after pressing.
- Stopper head 12 is manufactured in a hydraulic press with a density of 2,85g/crn J .
- Stopper body 10 is manufactured by isostatic pressing with a density of 2,5 g/cm 3 .
- the plug 20 is a graphite plug with an outer (external) thread 20t which fits with an inner (internal) thread 14t along those channel sections in the stopper body 10 and the stopper head 12, to which the plug is inserted.
- This plug arrangement gives the stopper a favorable structural integrity and avoids air ingress into the stopper head 12 to great extent.
- stopper body 10 and plug 20 gives the three part stopper further stability.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Abstract
The invention relates to a ceramic refractory stopper (a stopper device) for controlling a flow of molten metal at an outlet opening of a metallurgical vessel, such as a tundish.
Description
Description
Ceramic refractory stopper
The invention relates to a ceramic refractory stopper (a stopper device ) for controll ing a flow of molten metal at an outlet opening of a metallurgical vessel, such as a tundi sh .
The generic type of ceramic refractory stoppers compri ses a rod-shaped stopper body, one end secti on of which being designed for fixation to a corresponding lifting mechanism while the other end of which i s provi ded by the so call ed stopper head. The rod-shaped stopper body defines a centra! longitudinal axis.
It is wel l known in steel casting to arrange such a stopper rod, which in many- cases i s a one-piece-stopper rod, in a vertical position, in order to vary the cross-sectional area of an associated outl et opening of a corresponding metal lurgical vessel by said lifting action . Insofar any directi ons disclosed hereinafter, like "top", "bottom", "upper and lower ends" always refer to the verti cal use position as shown in Fig . 1 of the attached drawing.
Stopper rods of this type have also being used to introduce a gas, such as an inert gas, i . a. argon, into the molten steel for removing non-metallic inclusions from the molten m elt.
The invention yet does not deal with such gas purging stoppers but exclusively foeusses on stoppers to control the melt (out)f!ow in a
metallurgical melting and/or treatment vessel .
S uch generic stopper comprises
- a rod shaped stopper body, defining a central longitudinal axis (A), and
- a stopper head at a second end of the stopper body, providing a dome like outer surface,
- a channel of a l ength L, extending from a first end of said stopper body through said stopper body in a direction of said central longitudinal axis (A) towards the stopper head and into the stopper head , ending at a distance to the dome like outer surface.
The channel fulfils various tasks, i . a:
- it allows to arrange a corresponding mandrel during isostatic pressing,
- it all ows to integrate a fitting in the ceramic body for fixation of the stopper to the lifting mechanism,
- it reduces the material consumption and the weight of the stopper,
- it improves the thermo mechanical properties of the stopper.
A serious drawback of the channel is that air (oxygen) is sucked in and into the stopper head when the stopper is in use. A negative pressure may establish by the outfl owing metal stream around the stopper head. The air/oxygen may penetrate into the material/matrix of the stopper head and further leave the stopper head via its surface, penetrate into the metal melt and worsen the melt qual ity.
Another drawback i s that the oxygen, di ffusing through the stopper head , may react with the refractory material of the stopper head in an uncontrollable manner. If an MgO-C material is used for the stopper head, this effect may
even lead to chemical reactions between, carbon and oxygen and consequently to a loss of integrity of the stopper head.
Thi s is in particular a probl em in connection with the parallel demand for longer casting times, for example from 5h up to 24h.
Insofar it is an obj ect of the invention to provide a refractory ceramic stopper allowing longer use (casting) times without losing its integrity.
One maj or cognition of the invention is to prevent any air (oxygen) from being sucked into the channel via its first (upper) end and to continue (flow) into the stopper head .
One option (I) to achieve this i s to end the channel before the stopper head , i.e . to arrange the second lower end of a blind channel above the stopper head. In other words ; not to extend the channe l into the stopper head
(material) and correspondingly to make the whole stopper head of a refractory material, in particular a substantially dense refractory material with no relevant gas permeability so that any air fl ow stops more or less completely at the lowermost end of the channel .
This option (I) has several drawbacks : it increases the material need and thus the costs ; it makes manufacturing of a monolithic (one-piece) generic stopper rod. much more difficult and it worsens the physical parameters of the stopper head, in particular its thermal shock behavior.
Insofar the invention takes another way (II) . It keeps the channel design more or less unchanged but integrates a plug/barri er into the channel and - more prec isely - into the transition section of the channel between stopper body and stopper head. This barrier is selected to provide a gas permeabi lity as low
as possible to stop the air flow on its way towards and into the stopper head at its best.
The plug reduces or avoids any negative pressure and thus any suction o f air through the stopper head below this barrier (in its mounted position).
This plug allows to realize further technical aspects, in particular it provides a mechanical reinforcement of the stopper in its lower section, being the one undergoing hi gh stresses and wear.
The stopper head and the stopper body are further connected and stabilized by said intermediate and solid plug, protruding i nto the cavity (channel section) of the stopper head and into a corresponding (adj acent) channel section within the stopper body. This fixation may be achieved by a friction-fit arrangement (for example a slightly frustoconi cal shape of the plug;
corresponding threads along the plug and the channel), by an adhesive (for example a refractory binder) between adj acent parts and/or further
reinforcement means like an anchor, fixed with one end in said plug and with another end in the stopper body or in the stopper head.
At the same time, the wear behavior of the overall stopper is optimized.
In i ts most general embodiment the invention relates to a refractory ceramic stopper comprising
a) a rod shaped stopper body, defining a central longitudinal axis (A), and
b) a stopper head at a second end of the stopper body, providing a
dome like outer surface,
c) a channel o f length L, extending from a first end of said stopper body through said stopper body in a direction of said central
longitudinal axis (A) towards the stopper head and into the stopper head, ending at a distance to the dome like outer surface, d) a plug, arranged within sai d channel over its whol e cross-section and extending with a first part into the channel within the stopper body and with a second end into the channel within the stopper head, wherein
e) said plug has a gas permeabil ity smaller than 0,7 nPin .
The gas permeability is defined in accordance with Routschka "Taschenbuch Feuerfeste Werkstoffe" Vulkan Verlag, 2001 , pages 397ff, [IS BN 3 - 8027- 3 1 50-6] .
To achieve the favorable mechanical and thermo-mechanical features as mentioned above the plug extends to a depth into the stopper head leaving a terminal section of the channel unsealed : in. other words : The channel continues over a short distance below the fitted plug.
According to one embodiment the (typically blind) channel tapers between its first and second end. For example the sloping angle may be around 1 - 5°, for example 3 or 4 degrees. This al lows to optimize isostatic pressing of the stopper as the corresponding mandrel may easily be extracted after
manufacture. It further allows to arrange the plug in a favorable position within the channel, independently of whether the pl ug i s of constant cross section over its height (in the axial plug directi on) or tapered .
The channel may have any cross sectional profile but a circular cross section is of advantage for manufacturing and sealing the plug within the channel .
The plug i tself may as well have a circular cross secti on, perpendicul ar to the central longitudinal axis of the stopper body.
Correspondingly the plug may be of a substantially cylindrical or frustoconicai shape,
In case of a cylindrical shape it may be advantageous to provide a
circumferential shoulder along the channel wall onto which the plug is set or to use a plug with an external thread, fitting with a corresponding internal thread, of the channel (wall).
In case of a frustoconicai shape the smaller end in the use position of the stopper should be the lower end. This makes the arrangement (substantially gas tight positioning) of the plug within the channel easier.
Combinations of both design variations are possible, for example a
cylindrical plug with a tapered lower end.
The sloping angle of the plug (barrier means) may be in the same range as that for the channel or slightly smaller, which increases the respective friction and sealing effect between corresponding surfaces of plug and channel.
Optional features of the plug are one or more of the following: its largest cross section, perpendicular to the central longitudinal axis, being slightly larger than the cross section of the blind channel at a corresponding position; this allow a friction-fit arrangement of the plug within the channel without further means its height, parallel to the central longitudinal axis (A), being larger than its largest width, perpendicular to the central longitudinal axis (A).
Both design features improve the barrier effect of the plug within the channel.
According to another embodiment at least the stopper head is made of an MgO-C material. 'This has been proven favorable in conventional stoppers with the exception of reactions with air diffusing into the stopper head. As any air ingress is now avoided, the MgO-C material can be used without any drawbacks.
A further safety feature, not necessarily required but of advantage, especially when the stopper is intended to be used over long easting times, includes to use graphite (or another carbonaceous material to manufacture a plug of low gas permeability) as a material from which the plug is made.
The graphite plug not only stops the oxygen flow but its carbon may react with said oxygen within the channel sections above said plug and thus consumes said oxygen.
Other materials suitable for the barrier means are oxidic or non-oxidic refractory materials such as AI2O3, corundum, zircon, zirconia.
As mentioned the gas permeability of the plug, for example a pressed plug, should be as low as possible, in any case < 0,7 nPm, < 0,4 nPm < 0,2nPm, preferred <0,1 nPm or <0,05nPm.
The gas permeability of the material for the stopper head may be higher, for example: l-2nPm (especially l,0-l,3nPra) in case of an A!2C>3-C-material or 1-2 (especially 1,1-1,4) in case of an MgO-C-material.
The gas permeability is tested in accordance with DIN EN 993-4: 1995-04 at room temperature (20°C).
Other optional parameters of the refractory ceramic stopper are;
- the plug has a thermal expansion coefficient a (20-1000°C)
according to DIN 51909: 2009-05 of less than 10 x 10'6/K, the plug is made of a material in a grain, fraction d9o<64pm, often <20μπι,
- the plug has a density (according to DIN 51918: 1999-08) of 1,5- 3,5g/cm3,
at least one of the stopper body, the stopper head and the plug is an isostatically pressed part,
- the stopper body, the stopper head and the plug can also be pressed in-situ in an isostatic press.
A favorable way to manufacture a stopper of the type described is to shape the stopper head in a hydraulic press, which allows an in-situ forming of the terminal end of the channel and which leads to increased densities in the refractory wall of the stopper head by squeezing. These densities can be higher than those of the stopper body. In other words; The stopper features higher densities in the stopper head at positions offset to the stopper body. The
hydraulically pressed stopper head or a cast stopper head may be combined with an isostatically pressed stopper body, while the plug can be manufactured by either way or machined out of a monolithic body.
At least one of different interfaces between stopper body and plug, between stopper body and stopper head or between stopper head and plug can be covered with an adhesive (including a mortar) to glue adjacent surface section.
The new stopper allows longer casting tim.es compared with prior art. It is expected that casting times of up 24h with one single stopper will become possible.
The new design i s preferred in view of stoppers which provide a coated stopper head surface (WO 96/ 1 6758) as thi s coating undergoes severe wear during casting and l oses its function rapidly.
Further aspects of the invention derive from the features of the sub-claims and the other application documents.
The discl osed features may be combined arbitrarily if not explicitly excluded or absurd for the skil led man,
The inventi on wi ll now be described by way of an exampl e. In the schematic drawi ng :
Figure 1 shows a longitudinal sectional view of a first embodiment of the new stopper.
Figure 2 displays an enlarged side view of the plug according to Fig. 1
Figure 3 shows a longitudinal secti onal view of a second embodiment of the new stopper in the Figures identical structural elements or structural el ements of the same or similar function are referenced by the same numerals .
Figures 1 ,2 : The stopper compri ses a rod shaped stopper body 10, defining a central longitudinal axis A-A, and a stopper head 12 at a second end E2 of the stopper body 1 0, providing a dome like outer surface 12o, a blind channel 1 4 of length L, extending from a first end E l (upper surface l Ou) of said stopper body 1 0 through said stopper body 1 0 in a direction of said central
longitudinal axis A towards the stopper head 1 2 and into the stopper head 12,
ending at a distance d to the lowermost point P of said dome like outer surface 12o,
A fitting F is arranged around channel 14 within stopper body 10 at its upper end El to allow mechanical connection to an associated (now shown) lifting mechanism.
It further comprises a plug 20, arranged within said blind channel 14 over its whole cross-section, partly (20f) into a section 14t of the channel 14 within the stopper body 10 and parti)/ (20s) into a section of the channel 14 within the stopper head 12, with a terminal end section 14ts of the channel 14 remaining unsealed.
Said plug is arranged such that about 2/3 of its axial length (along A-A) protrude into channel part 14t above stopper head 10 and 1/3 protrudes into that section of channel 14 which extends into said stopper head 12.
The transition area between stopper body 10 (dashed lines) and stopper head 12 (crossed lines) is clearly visible in this embodiment.
As may be seen from the Figures channel 14 tapers between ends El and £2 slightly (3°) while it tapers strongly along its terminal end section 14ts within stopper head 12 with a cross section close to zero at its lowermost end 14u.
Plug 20 has a frustoconical shape as may be seen from Fig.2 with a sloping angle of 2,5° so that it fits perfectly within channel 14 and seals the channel 14 circumferentially against air ingress to any stopper sections below said plug 20.
Plug 20 is made of a graphite material with a density of 1,8 g/cm3 and has a gas permeability of 0,05 nPm.
-li
lts axial height is 1,1 times its diameter.
Stopper head 12 is made of a refractory MgO-C composition, while the stopper body is made of a conventional MgO material.
Stopper body 10 and stopper head 12 are manufactured commonly in an iostatic press (mould). The corresponding mandrel has a general shape corresponding to that of channel 14. The plug 20 is fitted into the channel 14 after pressing.
Figure 3 :
This embodiment differs from that of Figures 1,2 as follows:
Stopper head 12 is manufactured in a hydraulic press with a density of 2,85g/crnJ. Stopper body 10 is manufactured by isostatic pressing with a density of 2,5 g/cm3.
The plug 20 is a graphite plug with an outer (external) thread 20t which fits with an inner (internal) thread 14t along those channel sections in the stopper body 10 and the stopper head 12, to which the plug is inserted. This plug arrangement gives the stopper a favorable structural integrity and avoids air ingress into the stopper head 12 to great extent.
A refractory adhesive between corresponding/adjacent surfaces of stopper head 12, stopper body 10 and plug 20 gives the three part stopper further stability.
Claims
Patent Claims
Ceramic refractory stopper
1. Refractory ceramic stopper comprising
a) a rod shaped stopper body (10), defining a central longitudinal axis (A), and
b) a stopper head (12) at a second end (E2) of the stopper body (10). providing a dome like outer surface (12o),
c) a channel (14) of a length L, extending from a first end (El) of said stopper body (10) through said stopper body (10) in a direction of said central longitudinal axis (A) towards the stopper head (12) and into the stopper head (12), ending at a distance to the dome like outer surface (12o),
d) a plug (20), arranged within said channel (14) over its whole
cross-section , extending with a first part (20f) into the channel (14) within the stopper body (10) and with a second part (20s) into the channel (14) within the stopper head (12), wherein e) said plug (20) has a gas permeability smaller than 0,7nPm.
2. Refractory ceramic stopper according to claim 1, wherein said plug (20) extends into the stopper head (12) to a depth leaving a terminal section (14ts) of the channel (14) unsealed.
3. Refractory ceramic stopper according to claim 1, wherein the channel (14) tapers between its first (14 f ) and second (14s) end,
4. Refractory ceramic stopper according to claim 1, comprising a plug (20) of substantially cylindrical or frustoconical shape,
5. Refractory ceramic stopper according to claim 1, comprising a plug (20) of substantially circular cross section, perpendicular to its central longitudinal axis (A).
6. Refractory ceramic stopper according to claim 1, comprising a plug (20) with an external thread (20t), fitting with a corresponding internal thread (14t) along a corresponding section ( 14t) of the channel (14).
7. Refractory ceramic stopper according to claim 1. wherein at least the stopper head (12) is made of an MgO-C material,
8. Refractory ceramic stopper according to claim i, wherein the plug (20) is made of a material from the group comprising: graphite, AI2.O3, corundum, zircon, zirconia.
9. Refractory ceramic stopper according to claim 1, wherein the plug (20) has a thermal expansion coefficient a (20-1000°C) according to DIN 51909: 2009-05 of less than 10 x 10"6/K.
10. Refractory ceramic stopper according to claim 1, wherein the plug (20) is in-situ arranged within the stopper head (12) and the stopper body (10) during common isostatic pressing of said three parts (10, 12, 20). ί i . Refractory ceramic stopper according to claim L including -reinforcing means, one end of which being fixedly secured within the plug (20) while another end being fixed within the stopper body (10) or the stopper head (12).
12. Refractory ceramic stopper according to claim 1, wherein the stopper head (12) has zones of different densities with highest density offset the stopper body (10). ■
13. Refractory ceramic stopper according to claim 1, wherein the stopper body (10) is an isostatically pressed part with a density dl 0, the stopper head (12) is a hydraulicaily pressed or cast part featuring a density dl 2, wherein dl 2 of the hydrically pressed part being larger than dlO.
14. Refractory ceramic stopper according to claim 1, wherein at least one of different interfaces between stopper body (10) and plug (20), stopper body (10) and stopper head (12) or stopper head (12) and plug (20) is covered with an adhesive.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/EP2015/069753 WO2017036497A1 (en) | 2015-08-28 | 2015-08-28 | Ceramic refractory stopper |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/EP2015/069753 WO2017036497A1 (en) | 2015-08-28 | 2015-08-28 | Ceramic refractory stopper |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2017036497A1 true WO2017036497A1 (en) | 2017-03-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2015/069753 WO2017036497A1 (en) | 2015-08-28 | 2015-08-28 | Ceramic refractory stopper |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2017036497A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115673306A (en) * | 2022-11-14 | 2023-02-03 | 青岛正望新材料股份有限公司 | Plug rod for producing high-phosphorus amorphous alloy and manufacturing method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54112816U (en) * | 1978-01-30 | 1979-08-08 | ||
| WO1985005056A1 (en) * | 1984-05-05 | 1985-11-21 | Thor Ceramics Limited | Stopper for use in molten metal handling |
| WO1999028066A1 (en) * | 1997-11-27 | 1999-06-10 | Foseco International Limited | Stopper rod |
-
2015
- 2015-08-28 WO PCT/EP2015/069753 patent/WO2017036497A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54112816U (en) * | 1978-01-30 | 1979-08-08 | ||
| WO1985005056A1 (en) * | 1984-05-05 | 1985-11-21 | Thor Ceramics Limited | Stopper for use in molten metal handling |
| WO1999028066A1 (en) * | 1997-11-27 | 1999-06-10 | Foseco International Limited | Stopper rod |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115673306A (en) * | 2022-11-14 | 2023-02-03 | 青岛正望新材料股份有限公司 | Plug rod for producing high-phosphorus amorphous alloy and manufacturing method thereof |
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