GB2095612A - Improve monoblock one-piece pouring stopper - Google Patents

Improve monoblock one-piece pouring stopper Download PDF

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Publication number
GB2095612A
GB2095612A GB8209430A GB8209430A GB2095612A GB 2095612 A GB2095612 A GB 2095612A GB 8209430 A GB8209430 A GB 8209430A GB 8209430 A GB8209430 A GB 8209430A GB 2095612 A GB2095612 A GB 2095612A
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Prior art keywords
stopper
mould
monoblock
pouring
zirconia
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GB8209430A
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GB2095612B (en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • 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
    • B22D41/186—Stopper-rods therefor with means for injecting a fluid into the melt

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

A one-piece monoblock pouring stopper 1 has a nose portion 2 comprising a high refractory material selected from calcined alumina, fused alumina, magnesite and zirconia is disclosed. It is made by charging a mould with a refractory material and a bonding agent to a level short of the full capacity of the mould and filling the remaining volume with a higher refractory material selected from calcined alumina, fused alumina, magnesite and zirconia, together with a bonding agent such as foundry resin, compressing the contents of the mould, preferably by isostatic pressing, firing the compressed contents to form a monolithic structure and shaping the monolithic structure to form a one-piece monoblock stopper. <IMAGE>

Description

SPECIFICATION Improved monoblock one-piece pouring stopper This invention relates to monoblock one-piece pouring stoppers which are used as valve closures to control the outflow of molten metal through bottom pouring nozzles in foundry ladles or tun dishes in the iron and steel industry.
Each monoblock pouring stopper is made from a refractory material such as graphitized alumina or clay graphite.
These stoppers have been made in 2 pieces i.e.
an extruded clay graphite body with a screwed on nose cap, which could have a different composition to improve wear resistance.
In use the nose caps wear quickly due to erosion by the pressure of the outflowing melt through the nozzle of the tun dish or ladle and it has been proposed to improve the wear characteristics of the nose cap by the addition of fused or calcined alumina to the refractory mix formula.
Another type of monoblock pouring stopper has been developed which is formed in one-piece by an isostatic pressing of graphitized alumina.
However the effective life of this stopper is also shortened by erosion at the top of the stopper.
This necessitates removal of the stopper and reshaping and grinding of the tip in order to provide a good mating seal with the pouring nozzle in a ladle or tun dish.
In the modern continuous casting plants this interruption in production not only wastes time but also fuel due to the cooling to allow removal of the stopper and subsequent reheating required to attain operating temperatures when the stopper is replaced.
It is an object of the present invention to obviate or mitigate the aforesaid disadvantages.
According to the present invention there is provided a one-piece monoblock pouring stopper having a nose portion comprising a high refractory material selected from calcined alumina, fused alumina, magnesite and zirconia.
The most preferred high refractory additive material is stabilised or unstabilised zirconia.
Further according to the present invention there is provided a method of manufacturing a one piece monoblock pouring stopper comprising charging a mould with a refractory material and a bonding agent to a level short of the full capacity of the mould and filling the remaining volume with a higher refractory material selected from calcined alumina, fused alumina, magnesite and zirconia, together with a bonding agent, compressing the contents of the mould, firing the compressed contents to form a monolithic structure and shaping the monolithic structure to form a one piece monoblock stopper.
Preferably the mould is an isostatic pressing mould and compression of the contents thereof is effected by an isostatic pressing apparatus.
Most preferably, the method comprises charging the isostatic pressing mould with graphitized alumina bonded with a foundry type resin to a level short of the full capacity of the mould and filling the remaining volume with a mix of zirconia and a foundry resin as bonding agent.
A preferred embodiment of this invention will now be described by way of example with reference to the accompanying drawing in which a monoblock stopper is illustrated mounted in an operational position above a pouring nozzle of a tun-dish.
A one-piece monoblock pouring stopper according to this embodiment of the invention is formed by a high intensity mixing of graphite and alumina powder together with foundry resin as bonding agent to form a homogeneous mix and charging the mix to a normal isostatic pressing mould to a level short of the full capacity of the mould.
A graded batch of zirconia together with a phenolic resin bonding agent, optionally including other minor ingredients such as graphite, is blended in a high intensity mixer to form a homogeneous blend and the blend is added to the mould to fill the remaining volume.
The mould is sealed and immersed in water and subjected to isostatic pressing. The compressed contents of the mould are then fired to form a monolithic structure which can then be shaped to form a one-piece monoblock stopper provided with an integral armoured nose portion of zirconia which is more highly resistant to erosion. Thus such a stopper has an extended working life.
In use a one-piece monoblock stopper 1 having an armoured nose portion 2 is fixed by conventional means to a cross arm control member 3 above the pouring nozzle 4 of a tun dish 5.
By raising or lowering of the control member 3 the armoured nose portion 2 of the stopper 1 increases or reduces the outflow volume of molten metal 6 through the pouring nozzle 4 into a continuous casting mould 7 wherein the molten metal begins to solidify to a mass 8 suitable for subsequent rolling.
The aperture 9, which allows the optional step of injection of argon gas through the stopper into the metal, may not be present in other embodiments so as to leave a thick solid armoured nose. This solid coating is advantageous in cases of severe wear.
1. A method of manufacturing a one-piece monoblock pouring stopper comprising charging a mould with a refractory material and a bonding agent to a level short of the full capacity of the mould and filling the remaining volume with a high refractory material selected from calcined alumina, fused alumina, magnesite and zirconia, together with a bonding agent, compressing the contents of the mould, firing the compressed contents to form a monolithic structure and shaping the monolithic structure to form a onepiece monoblock stopper.
2. A method according to claim 1,Lvherein the
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improved monoblock one-piece pouring stopper This invention relates to monoblock one-piece pouring stoppers which are used as valve closures to control the outflow of molten metal through bottom pouring nozzles in foundry ladles or tun dishes in the iron and steel industry. Each monoblock pouring stopper is made from a refractory material such as graphitized alumina or clay graphite. These stoppers have been made in 2 pieces i.e. an extruded clay graphite body with a screwed on nose cap, which could have a different composition to improve wear resistance. In use the nose caps wear quickly due to erosion by the pressure of the outflowing melt through the nozzle of the tun dish or ladle and it has been proposed to improve the wear characteristics of the nose cap by the addition of fused or calcined alumina to the refractory mix formula. Another type of monoblock pouring stopper has been developed which is formed in one-piece by an isostatic pressing of graphitized alumina. However the effective life of this stopper is also shortened by erosion at the top of the stopper. This necessitates removal of the stopper and reshaping and grinding of the tip in order to provide a good mating seal with the pouring nozzle in a ladle or tun dish. In the modern continuous casting plants this interruption in production not only wastes time but also fuel due to the cooling to allow removal of the stopper and subsequent reheating required to attain operating temperatures when the stopper is replaced. It is an object of the present invention to obviate or mitigate the aforesaid disadvantages. According to the present invention there is provided a one-piece monoblock pouring stopper having a nose portion comprising a high refractory material selected from calcined alumina, fused alumina, magnesite and zirconia. The most preferred high refractory additive material is stabilised or unstabilised zirconia. Further according to the present invention there is provided a method of manufacturing a one piece monoblock pouring stopper comprising charging a mould with a refractory material and a bonding agent to a level short of the full capacity of the mould and filling the remaining volume with a higher refractory material selected from calcined alumina, fused alumina, magnesite and zirconia, together with a bonding agent, compressing the contents of the mould, firing the compressed contents to form a monolithic structure and shaping the monolithic structure to form a one piece monoblock stopper. Preferably the mould is an isostatic pressing mould and compression of the contents thereof is effected by an isostatic pressing apparatus. Most preferably, the method comprises charging the isostatic pressing mould with graphitized alumina bonded with a foundry type resin to a level short of the full capacity of the mould and filling the remaining volume with a mix of zirconia and a foundry resin as bonding agent. A preferred embodiment of this invention will now be described by way of example with reference to the accompanying drawing in which a monoblock stopper is illustrated mounted in an operational position above a pouring nozzle of a tun-dish. A one-piece monoblock pouring stopper according to this embodiment of the invention is formed by a high intensity mixing of graphite and alumina powder together with foundry resin as bonding agent to form a homogeneous mix and charging the mix to a normal isostatic pressing mould to a level short of the full capacity of the mould. A graded batch of zirconia together with a phenolic resin bonding agent, optionally including other minor ingredients such as graphite, is blended in a high intensity mixer to form a homogeneous blend and the blend is added to the mould to fill the remaining volume. The mould is sealed and immersed in water and subjected to isostatic pressing. The compressed contents of the mould are then fired to form a monolithic structure which can then be shaped to form a one-piece monoblock stopper provided with an integral armoured nose portion of zirconia which is more highly resistant to erosion. Thus such a stopper has an extended working life. In use a one-piece monoblock stopper 1 having an armoured nose portion 2 is fixed by conventional means to a cross arm control member 3 above the pouring nozzle 4 of a tun dish 5. By raising or lowering of the control member 3 the armoured nose portion 2 of the stopper 1 increases or reduces the outflow volume of molten metal 6 through the pouring nozzle 4 into a continuous casting mould 7 wherein the molten metal begins to solidify to a mass 8 suitable for subsequent rolling. The aperture 9, which allows the optional step of injection of argon gas through the stopper into the metal, may not be present in other embodiments so as to leave a thick solid armoured nose. This solid coating is advantageous in cases of severe wear. CLAIMS
1. A method of manufacturing a one-piece monoblock pouring stopper comprising charging a mould with a refractory material and a bonding agent to a level short of the full capacity of the mould and filling the remaining volume with a high refractory material selected from calcined alumina, fused alumina, magnesite and zirconia, together with a bonding agent, compressing the contents of the mould, firing the compressed contents to form a monolithic structure and shaping the monolithic structure to form a onepiece monoblock stopper.
2. A method according to claim 1,Lvherein the mould is an isostatic pressing mould and compression of the contents thereof is effected by an isostatic pressing apparatus.
3. A method according to claim 2, wherein the isostatic pressing mould is charged with graphitized alumina bonded with a foundry type resin to a level short of the full capacity of the mould and the remaining volume is filled with a mix of zirconia and a foundry resin as bonding agent.
4. A monoblock stopper whenever produced by a method according to any one of claims 1 to 3.
5. A one-piece monoblock stopper having an integral armoured nose portion comprising zirconia bound with a foundry resin.
GB8209430A 1981-04-01 1982-03-31 A stopper for a foundry mould Expired GB2095612B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8209430A GB2095612B (en) 1981-04-01 1982-03-31 A stopper for a foundry mould

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8110120 1981-04-01
GB8209430A GB2095612B (en) 1981-04-01 1982-03-31 A stopper for a foundry mould

Publications (2)

Publication Number Publication Date
GB2095612A true GB2095612A (en) 1982-10-06
GB2095612B GB2095612B (en) 1985-02-06

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4706944A (en) * 1984-05-05 1987-11-17 Thor Ceramics Limited Stopper for use in molten metal handling
US4791978A (en) * 1987-11-25 1988-12-20 Vesuvius Crucible Company Gas permeable stopper rod
FR2699841A1 (en) * 1992-12-28 1994-07-01 Vesuvius France Sa Flow control cap for vessel contg. molten metal
FR2727340A1 (en) * 1994-11-28 1996-05-31 Vesuvius France Sa COWL WITH AN EXTERNAL LAYER CAPABLE OF FORMING A GAS WATERPROOF LAYER
US5691061A (en) * 1994-06-15 1997-11-25 Vesuvius Crucible Company Refractory shape having an external layer capable of forming a layer impermeable to gases and process for its preparation
EP1110646A2 (en) * 1999-12-24 2001-06-27 Veitsch-Radex GmbH Stopper rod
WO2001091950A1 (en) * 2000-05-29 2001-12-06 Rotary Nozzle International S.A. Refractory plate
US6479175B1 (en) 1998-05-05 2002-11-12 Didier-Werke Ag Ceramic composite
CN108907169A (en) * 2018-07-06 2018-11-30 苏州宝明高温陶瓷有限公司 A kind of stopper and its forming method for preventing caput from cracking

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4706944A (en) * 1984-05-05 1987-11-17 Thor Ceramics Limited Stopper for use in molten metal handling
US4791978A (en) * 1987-11-25 1988-12-20 Vesuvius Crucible Company Gas permeable stopper rod
EP0320481A1 (en) * 1987-11-25 1989-06-14 Vesuvius International Corporation Gas permeable stopper rod
FR2699841A1 (en) * 1992-12-28 1994-07-01 Vesuvius France Sa Flow control cap for vessel contg. molten metal
US5691061A (en) * 1994-06-15 1997-11-25 Vesuvius Crucible Company Refractory shape having an external layer capable of forming a layer impermeable to gases and process for its preparation
WO1996016758A1 (en) * 1994-11-28 1996-06-06 Vesuvius France S.A. Stopper rod with an outer layer for forming a gas-tight layer
FR2727340A1 (en) * 1994-11-28 1996-05-31 Vesuvius France Sa COWL WITH AN EXTERNAL LAYER CAPABLE OF FORMING A GAS WATERPROOF LAYER
US6479175B1 (en) 1998-05-05 2002-11-12 Didier-Werke Ag Ceramic composite
EP1110646A2 (en) * 1999-12-24 2001-06-27 Veitsch-Radex GmbH Stopper rod
EP1110646A3 (en) * 1999-12-24 2001-10-10 Veitsch-Radex GmbH Stopper rod
WO2001091950A1 (en) * 2000-05-29 2001-12-06 Rotary Nozzle International S.A. Refractory plate
BE1013540A3 (en) * 2000-05-29 2002-03-05 Rotary Nozzle Internat S A Refractory plate.
CN108907169A (en) * 2018-07-06 2018-11-30 苏州宝明高温陶瓷有限公司 A kind of stopper and its forming method for preventing caput from cracking
CN108907169B (en) * 2018-07-06 2020-09-11 苏州宝明高温陶瓷有限公司 Stopper rod capable of preventing rod head from cracking and forming method thereof

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Publication number Publication date
GB2095612B (en) 1985-02-06

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