EP0178053A1 - Pouring tubes - Google Patents
Pouring tubes Download PDFInfo
- Publication number
- EP0178053A1 EP0178053A1 EP85305872A EP85305872A EP0178053A1 EP 0178053 A1 EP0178053 A1 EP 0178053A1 EP 85305872 A EP85305872 A EP 85305872A EP 85305872 A EP85305872 A EP 85305872A EP 0178053 A1 EP0178053 A1 EP 0178053A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- sleeve
- pouring tube
- protective sleeve
- tube according
- metal casing
- 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.)
- Granted
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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
- B22D41/50—Pouring-nozzles
- B22D41/505—Rings, inserts or other means preventing external nozzle erosion by the slag
Definitions
- This invention relates to pouring tubes for use in the casting of molten metal.
- the invention is particularly suited to the continuous casting of metals, particularly in the case of tubes for use between a ladle and a tundish, for which the invention is now more specifically described below.
- the invention is not confined to use in continuous casting as it may be used in other enclosed molten metal pouring systems.
- molten metal e.g. steel is passed from a ladle into a tundish which serves to maintain a constant head of molten metal.
- the metal flows out from the base of the tundish through one or more nozzles into one or more continuous casting moulds.
- the quality of the cast metal, withdrawn from the base of the mould as a strand for subsequent use as billets, blooms or slabs, can be adversely affected by oxide and other non-metallic inclusions which may be entrained if the molten metal stream is not protected adequately as it flows between the ladle and the mould or moulds.
- inert gas e.g. argon can be passed through the tube around the molten metal stream thereby enhancing the minimisation of access by atmospheric oxygen and nitrogen to the stream.
- Pouring tubes may be formed from highly refractory materials such as graphitised alumina, fused silica, or zirconia but these are very costly to produce and consequently for economic reasons their use cannot always be justified.
- pouring tubes have been proposed which comprise a tubular structure formed of refractory, heat-insulating material in the form of a tube encased by thin sheet metal e.g. steel.
- These pouring tubes albeit expendable i.e. they have a limited useful service life expectancy, still possess several advantages not least their initial low cost, ease of manufacture and low-density which contributes to easier handling during installation and removal after casting.
- the outer casing may be provided with a close fitting protective sleeve of heat-insulating material located over that portion of the tube which in use is contacted by the molten metal and/or slag held in a tundish.
- the outer protective sleeve is generally located at the lower end of a pouring tube and extends upwards for a sufficient length so as to project at least 50 mm above the anticipated level of the upper surface of the molten metal held in a tundish.
- This sleeve protects the pouring tube from slag attack and the metal casing from premature melting. Without the protective sleeve the metal casing will melt not only below the surface of the molten metal in the tundish but also for a distance of say about 15 to 30 mm above the slag/metal surface. Furthermore the metal casing may melt before sufficient sintering of the refractory, heat-insulating material of the pouring tube has occurred to strengthen it, with the result that the tube will be weak and exhibit a tendency to fracture.
- the protective sleeve may fail in service due to premature cracking.
- the cracking generally extends substantially along the length of the sleeve and tends to occur within 30 to 40 minutes of commencement of casting e.g. during the time taken to cast one ladle of molten steel. Once the sleeve has cracked the molten metal/slag attacks the metal casing and may cause the entire pouring tube to fail.
- a pouring tube assembly for use in the casting of molten metal which comprises a refractory, heat-insulating tube portion encased by a sheet metal casing, the casing having over at least part of its length a protective heat-insulating sleeve thereon, the protective sleeve and the metal casing being spaced apart over at least a part of the length of the sleeve.
- the space between the sleeve and the metal casing is preferably upto 2 mm, and is preferably within that part of the sleeve which is uppermost in use.
- the protective sleeve may be in contact with the metal casing for at least a part of the length of the casing.
- the protective sleeve may be formed by the well-known slurry methods from a mixture of refractory filler material, fibrous material and binders.
- the preferred refractory filler material may be selected from one or more of alumina, calcined magnesite, silica, chamotte, olivine, zircon, chromite, calcined bauxite or other oxides and silicates.
- the fibrous material is preferably one or more of calcium silicate fibre, aluminosilicate fibre, rockwool or slag wool.
- the binder is preferably an organic binder e.g.
- the sleeve may be formed such that it is more refractory at the zone where it is contacted by molten slag in use in a tundish.
- the protective sleeve may have a dressing of refractory paint or like coating to resist the erosive and/or chemical attack from the molten metal and accompanying slag held in the tundish.
- the space between the protective sleeve and the metal casing may be filled with a preformed compressible gasket or sleeve formed of e.g. a highly fibrous very low density material such as calcium silicate fibre, aluminosilicate fibre, rockwool, slag wool or glass fibre.
- a low density fillers such as expanded perlite, expanded vermiculite, or calcined rice husks may be used with or without a binding agent.
- the protective sleeve may be formed at least in part as a duplex structure so as to include the compressible gasket or sleeve as the innermost layer of the structure.
- Other variants include wrapping at least part of the metal casing with heat-insulating tape or blanket prior to the addition of the sleeve or loosely tamping a fibre filler into the space between the sleeve and the casing after the protective sleeve has been located on the pouring tube.
- a pouring tube comprises a refractory, heat-insulating material tube 1 encased over its length by a mild steel casing 2.
- the pouring tube has a flared upper end 3, to mate with the outlet from a metallurgical vessel (not shown).
- a heat-insulating protective sleeve 4 is located around the metal casing in a spaced apart relationship over part 5 of the length of the sleeve.
- a tapered pouring tube comprises a refractory, heat-insulating material tube 6 encased over its length by a mild steel casing 7.
- the tube has a plain upper end 8 to locate with the outlet from a ladle (not shown).
- a heat-insulating protective sleeve 9 is located around the metal casing in a spaced apart relationship over the length of the sleeve by means of the inner compressible aluminosilicate fibre layer 10.
- a pouring tube according to the present invention was used to continuously cast a low- carbon fully aluminium-killed steel at a temperature of 1550°C for a duration of 4 hours. At the end of the casting sequence no significant deterioration of the pouring tube was evident and the outside surface of the immersed portion of the tube exhibited minimum erosion indicating that the tube of the present invention would have been capable of withstanding an even longer duration continuous casting sequence.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Endoscopes (AREA)
- Mechanical Coupling Of Light Guides (AREA)
- Ultra Sonic Daignosis Equipment (AREA)
- Ceramic Products (AREA)
- Thermal Insulation (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
Description
- This invention relates to pouring tubes for use in the casting of molten metal.
- The invention is particularly suited to the continuous casting of metals, particularly in the case of tubes for use between a ladle and a tundish, for which the invention is now more specifically described below. However, it should be appreciated that the invention is not confined to use in continuous casting as it may be used in other enclosed molten metal pouring systems.
- In continuous casting, molten metal e.g. steel is passed from a ladle into a tundish which serves to maintain a constant head of molten metal. The metal flows out from the base of the tundish through one or more nozzles into one or more continuous casting moulds. The quality of the cast metal, withdrawn from the base of the mould as a strand for subsequent use as billets, blooms or slabs, can be adversely affected by oxide and other non-metallic inclusions which may be entrained if the molten metal stream is not protected adequately as it flows between the ladle and the mould or moulds.
- A number of proposals have been suggested in which' the stream of molten metal flowing from the base of a ladle is surrounded by a ladle stream protection tube i.e. a pouring tube. Use of the tube minimises the deleterious oxidation effects of atmospheric oxygen on the molten metal, serves as a heat shield, thereby protecting operatives working near the stream of molten metal from radiant heat, noxious fumes and any sparks or stray molten metal droplets that may arise from unshielded streams.
- Moreover, inert gas e.g. argon can be passed through the tube around the molten metal stream thereby enhancing the minimisation of access by atmospheric oxygen and nitrogen to the stream.
- Pouring tubes may be formed from highly refractory materials such as graphitised alumina, fused silica, or zirconia but these are very costly to produce and consequently for economic reasons their use cannot always be justified.
- Alternatively, pouring tubes have been proposed which comprise a tubular structure formed of refractory, heat-insulating material in the form of a tube encased by thin sheet metal e.g. steel. These pouring tubes, albeit expendable i.e. they have a limited useful service life expectancy, still possess several advantages not least their initial low cost, ease of manufacture and low-density which contributes to easier handling during installation and removal after casting. The outer casing may be provided with a close fitting protective sleeve of heat-insulating material located over that portion of the tube which in use is contacted by the molten metal and/or slag held in a tundish.
- The improved heat-insulating properties and low density of the expendable tubes compared with the highly refractory tubes considerably reduces the amount of heat radiated to the surroundings and, accordingly, the degree of super-heat applied to the molten metal in the ladle may be reduced.
- The outer protective sleeve is generally located at the lower end of a pouring tube and extends upwards for a sufficient length so as to project at least 50 mm above the anticipated level of the upper surface of the molten metal held in a tundish.
- This sleeve protects the pouring tube from slag attack and the metal casing from premature melting. Without the protective sleeve the metal casing will melt not only below the surface of the molten metal in the tundish but also for a distance of say about 15 to 30 mm above the slag/metal surface. Furthermore the metal casing may melt before sufficient sintering of the refractory, heat-insulating material of the pouring tube has occurred to strengthen it, with the result that the tube will be weak and exhibit a tendency to fracture. If fortuitously the tube remains intact, the absence of the casing above the molten metal will permit the ingress of air due to the porous nature of the refractory, heat-insulating tube portion which completely negates a most important function of the pouring tube i.e. to protect the molten metal stream from atmospheric oxidation.
- However, it has been observed that the protective sleeve may fail in service due to premature cracking. The cracking generally extends substantially along the length of the sleeve and tends to occur within 30 to 40 minutes of commencement of casting e.g. during the time taken to cast one ladle of molten steel. Once the sleeve has cracked the molten metal/slag attacks the metal casing and may cause the entire pouring tube to fail.
- According to the present invention there is provided a pouring tube assembly for use in the casting of molten metal which comprises a refractory, heat-insulating tube portion encased by a sheet metal casing, the casing having over at least part of its length a protective heat-insulating sleeve thereon, the protective sleeve and the metal casing being spaced apart over at least a part of the length of the sleeve.
- The space between the sleeve and the metal casing is preferably upto 2 mm, and is preferably within that part of the sleeve which is uppermost in use. The protective sleeve may be in contact with the metal casing for at least a part of the length of the casing.
- The protective sleeve may be formed by the well-known slurry methods from a mixture of refractory filler material, fibrous material and binders. The preferred refractory filler material may be selected from one or more of alumina, calcined magnesite, silica, chamotte, olivine, zircon, chromite, calcined bauxite or other oxides and silicates. The fibrous material is preferably one or more of calcium silicate fibre, aluminosilicate fibre, rockwool or slag wool. The binder is preferably an organic binder e.g. a synthetic resin binder such as phenol-formaldehyde resin, urea-formaldehyde resin or mixtures of these. The sleeve may be formed such that it is more refractory at the zone where it is contacted by molten slag in use in a tundish.
- The protective sleeve may have a dressing of refractory paint or like coating to resist the erosive and/or chemical attack from the molten metal and accompanying slag held in the tundish.
- The space between the protective sleeve and the metal casing may be filled with a preformed compressible gasket or sleeve formed of e.g. a highly fibrous very low density material such as calcium silicate fibre, aluminosilicate fibre, rockwool, slag wool or glass fibre. Optionally, one or more low density fillers such as expanded perlite, expanded vermiculite, or calcined rice husks may be used with or without a binding agent.
- Alternatively, the protective sleeve may be formed at least in part as a duplex structure so as to include the compressible gasket or sleeve as the innermost layer of the structure. Other variants include wrapping at least part of the metal casing with heat-insulating tape or blanket prior to the addition of the sleeve or loosely tamping a fibre filler into the space between the sleeve and the casing after the protective sleeve has been located on the pouring tube.
- The invention is further described with reference to the accompanying diagrammatic drawings in which:
- Figure 1 is a section through a parallel sided, pouring tube (having a flared top portion) of the invention and
- Figure 2 is a section through a tapered pouring tube of the invention in which the protective sleeve has a duplex construction.
- Referring to Figure 1 a pouring tube comprises a refractory, heat-insulating material tube 1 encased over its length by a
mild steel casing 2. The pouring tube has a flared upper end 3, to mate with the outlet from a metallurgical vessel (not shown). A heat-insulating protective sleeve 4 is located around the metal casing in a spaced apart relationship overpart 5 of the length of the sleeve. - Referring to Figure 2, a tapered pouring tube comprises a refractory, heat-insulating
material tube 6 encased over its length by a mild steel casing 7. The tube has a plain upper end 8 to locate with the outlet from a ladle (not shown). A heat-insulatingprotective sleeve 9 is located around the metal casing in a spaced apart relationship over the length of the sleeve by means of the inner compressiblealuminosilicate fibre layer 10. - A pouring tube according to the present invention was used to continuously cast a low- carbon fully aluminium-killed steel at a temperature of 1550°C for a duration of 4 hours. At the end of the casting sequence no significant deterioration of the pouring tube was evident and the outside surface of the immersed portion of the tube exhibited minimum erosion indicating that the tube of the present invention would have been capable of withstanding an even longer duration continuous casting sequence.
Claims (11)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT85305872T ATE31493T1 (en) | 1984-09-06 | 1985-08-19 | POURING PIPES. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8422486 | 1984-09-06 | ||
GB848422486A GB8422486D0 (en) | 1984-09-06 | 1984-09-06 | Pouring tubes |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0178053A1 true EP0178053A1 (en) | 1986-04-16 |
EP0178053B1 EP0178053B1 (en) | 1987-12-23 |
Family
ID=10566328
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP85305872A Expired EP0178053B1 (en) | 1984-09-06 | 1985-08-19 | Pouring tubes |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0178053B1 (en) |
AT (1) | ATE31493T1 (en) |
DE (1) | DE3561230D1 (en) |
GB (1) | GB8422486D0 (en) |
IN (1) | IN163869B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0402673A2 (en) * | 1989-06-16 | 1990-12-19 | General Electric Company | Transfer tube |
WO2001072454A1 (en) * | 2000-03-29 | 2001-10-04 | Sms Demag Aktiengesellschaft | Method and device for the continuous casting of aluminum-killed steels by means of a water-cooled permanent mold |
FR2830473A1 (en) * | 2001-10-10 | 2003-04-11 | Andre Daussan | Manufacture of pouring tube for molten metal involves pouring a refractive sintering compound is into an annular space between an external metallic ferrule and an internal refractive forming tube |
FR2830472A1 (en) * | 2001-10-10 | 2003-04-11 | Andre Daussan | Manufacture of pouring tube for molten metal involves pouring a refractive sintering compound is into an annular space between an external metallic ferrule and an internal refractive forming tube |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE679008A (en) * | 1965-04-08 | 1966-10-04 | ||
FR1493389A (en) * | 1966-09-22 | 1967-08-25 | United States Steel Corp | Device for continuous metal casting |
FR2285946A1 (en) * | 1974-09-27 | 1976-04-23 | Didier Werke Ag | CASTING OUTLET PLUNGE KIT FOR CONTINUOUS STEEL CASTING PLANTS |
WO1982001836A1 (en) * | 1980-11-26 | 1982-06-10 | Daussan Jean C | Thermally insulating casting tube for metallurgic container |
EP0102292A2 (en) * | 1982-08-23 | 1984-03-07 | Daussan Et Compagnie | Tubes for pouring molten metal |
-
1984
- 1984-09-06 GB GB848422486A patent/GB8422486D0/en active Pending
-
1985
- 1985-08-19 AT AT85305872T patent/ATE31493T1/en active
- 1985-08-19 EP EP85305872A patent/EP0178053B1/en not_active Expired
- 1985-08-19 DE DE8585305872T patent/DE3561230D1/en not_active Expired
- 1985-09-06 IN IN240/BOM/85A patent/IN163869B/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE679008A (en) * | 1965-04-08 | 1966-10-04 | ||
FR1493389A (en) * | 1966-09-22 | 1967-08-25 | United States Steel Corp | Device for continuous metal casting |
FR2285946A1 (en) * | 1974-09-27 | 1976-04-23 | Didier Werke Ag | CASTING OUTLET PLUNGE KIT FOR CONTINUOUS STEEL CASTING PLANTS |
WO1982001836A1 (en) * | 1980-11-26 | 1982-06-10 | Daussan Jean C | Thermally insulating casting tube for metallurgic container |
EP0102292A2 (en) * | 1982-08-23 | 1984-03-07 | Daussan Et Compagnie | Tubes for pouring molten metal |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0402673A2 (en) * | 1989-06-16 | 1990-12-19 | General Electric Company | Transfer tube |
EP0402673A3 (en) * | 1989-06-16 | 1992-09-09 | General Electric Company | Transfer tube |
WO2001072454A1 (en) * | 2000-03-29 | 2001-10-04 | Sms Demag Aktiengesellschaft | Method and device for the continuous casting of aluminum-killed steels by means of a water-cooled permanent mold |
FR2830473A1 (en) * | 2001-10-10 | 2003-04-11 | Andre Daussan | Manufacture of pouring tube for molten metal involves pouring a refractive sintering compound is into an annular space between an external metallic ferrule and an internal refractive forming tube |
FR2830472A1 (en) * | 2001-10-10 | 2003-04-11 | Andre Daussan | Manufacture of pouring tube for molten metal involves pouring a refractive sintering compound is into an annular space between an external metallic ferrule and an internal refractive forming tube |
EP1302262A1 (en) * | 2001-10-10 | 2003-04-16 | André Daussan | Process for manufacturing a casting tube |
Also Published As
Publication number | Publication date |
---|---|
GB8422486D0 (en) | 1984-10-10 |
IN163869B (en) | 1988-12-03 |
ATE31493T1 (en) | 1988-01-15 |
DE3561230D1 (en) | 1988-02-04 |
EP0178053B1 (en) | 1987-12-23 |
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