WO2007021207A1 - Snorkels for vacuum degassing of steel - Google Patents
Snorkels for vacuum degassing of steel Download PDFInfo
- Publication number
- WO2007021207A1 WO2007021207A1 PCT/PL2005/000078 PL2005000078W WO2007021207A1 WO 2007021207 A1 WO2007021207 A1 WO 2007021207A1 PL 2005000078 W PL2005000078 W PL 2005000078W WO 2007021207 A1 WO2007021207 A1 WO 2007021207A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- snorkel
- recirculating
- snorkels
- steel
- vacuum
- Prior art date
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 37
- 239000010959 steel Substances 0.000 title claims abstract description 37
- 238000009849 vacuum degassing Methods 0.000 title description 8
- 230000003134 recirculating effect Effects 0.000 claims abstract description 21
- 239000000919 ceramic Substances 0.000 claims abstract description 10
- 238000001816 cooling Methods 0.000 claims abstract description 8
- 239000011261 inert gas Substances 0.000 claims abstract description 5
- 238000007792 addition Methods 0.000 claims abstract description 3
- 238000005275 alloying Methods 0.000 claims abstract description 3
- 239000007789 gas Substances 0.000 claims description 3
- 239000007788 liquid Substances 0.000 description 7
- 239000010410 layer Substances 0.000 description 6
- 238000007872 degassing Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 239000011214 refractory ceramic Substances 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
- C22B9/04—Refining by applying a vacuum
Definitions
- the subject of his invention are the snorkels for recirculating vacuum-degassing of steel.
- the process of vacuum degassing of steel in steel ladle has the purpose of reducing the content harmful gasses dissolved in steel as hydrogen, oxygen, nitrogen, as well as decarbourizing and raising steel purity, thus improving its mechanical properties.
- the vacuum-chamber throat located in its lower section, consists of separate ceramic rings connected to the metal-drawing and recirculating snorkels, located coaxially to each other and their internal refractory lining is made of many layers of ceramic blocks arranged next to each other in one circumferential line.
- liquid steel is drawn from the ladle to the vacuum chamber of the, RH unit, whereby the steel is circulated due to inert gas, preferably argon, being supplied through metal-drawing snorkel.
- inert gas preferably argon
- the inert gas pumps liquid steel into vacuum chamber through the metal- drawing snorkel, wherefrom, after its degassing, the steel returns to the ladle through the other, recirculating snorkel.
- Liquid steel is drawn only up to the level of the barometric pressure column which depends on external pressure and the pressure in the vacuum chamber.
- the external refractory lining of snorkels has a relatively short service life because of concrete-dissolving chemical corrosion that takes place in their service as a result of direct contact with the liquid layer of slag and having a destructive effect on the refractory lining of snorkels.
- the concrete surface is sprayed with alkaline mass during time breaks between consecutive steel melting cycles. Thus, a layer of material that protects the concrete against direct contact with liquid slag is created.
- the essence of the snorkels for recirculating vacuum-degassers of steel consists in manufacturing of metal-drawing and recirculating snorkels as well as vacuum-chamber throat rings in degassers as monolithic sets, in which ceramic blocks of the internal lining are made of several layers of rings bound together with similar overlapping blocks, with perforation being made on/in external refractory concrete lining of those monolithic sets.
- the steel casings of both snorkels are provided with cooling systems, preferably gas cooling systems.
- fig. 1 is a perspective view of either metal-drawing or recirculating snorkel with perforated surface of external refractory lining of the recirculating vacuum-degasser of steel
- fig. 2 is a perspective view of the steel casing of the snorkel shown in fig. 1 with an arrangement of cooling pipes
- fig. 3 is a perspective view of a fragment of vacuum chamber of the recirculating vacuum-degasser of steel in axial cross-section.
- the throat I of the vacuum chamber 2 of the recirculating vacuum-degasser of steel is provided with metal-drawing snorkel 3 and recirculating snorkel 4.
- Each of these snorkels, 3 and 4 is made as the monolith, 5 and 6, consisting of steel casing 7 with refractory lining 8_ on its external surface and a sleeve element 9 of refractory ceramic blocks iO located inside of that casing, so that the sleeve element 9 covers a set of pipes of the gas cooling system JJ, mounted on the internal surface of the steel casing 7 and projecting above its upper face by a dimension L which is equal to approx. 40 % of its total height H.
- external refractory lining 8 of the steel casing 7 is provided with perforation 12 all over its surface, whereas the refractory ceramic blocks H) of the sleeve element 9 are arranged alternately next to each other so that they form overlaps 1_3 with the neighboring ceramic blocks jj).
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Snorkels of recirculating vacuum-degasser of steel installed in the lower section of the vacuum chamber of the degasser unit, one of which is the metal-drawing snorkel equipped with pipe supplying inert gas to ladle and the other is a recirculating snorkel, the lower section of said vacuum chamber being provided with chute for alloying additions, burner hole and gas-suction duct and for vacuum creation in the chamber, internal and external linings of said snorkels being held by steel casings, wherein said metal-drawing snorkel (3) and said recirculating snorkel (4) and rings of the throat (1) of said vacuum chamber (2) of said degasser unit are made as monolithic sets (5) and (6) in which ceramic blocks (10) of the internal lining are made of several layers of rings bound with each other with similar blocks overlapping each other, said external refractory lining (8) of said metal-drawing snorkel (3) and said recirculating snorkel (4) in both of said monolithic sets (5) and (6) being provided with perforation (12), whereas said steel casings (7) of said sets being provided with a cooling system (11).
Description
Snorkels for vacuum degassing of steel
The subject of his invention are the snorkels for recirculating vacuum-degassing of steel.
The process of vacuum degassing of steel in steel ladle has the purpose of reducing the content harmful gasses dissolved in steel as hydrogen, oxygen, nitrogen, as well as decarbourizing and raising steel purity, thus improving its mechanical properties.
Many methods of vacuum degassing of steel are known, among them the RH recirculating vacuum-degassing process consisting in metal circulation through a vacuum chamber of an RH degasser equipped with a ladle for liquid steel, provided with a metal-drawing snorkel that contains an inert gas supply pipe and a recirculating snorkel. During the steel degassing process both snorkels are inserted into liquid steel in the ladle that is situated below the chamber of the degasser unit. Besides, the RH degasser is equipped with chute for alloying additions, a burner hole and, in its upper section, a gas-suction duct and a pipe for vacuum creation in the chamber.
The vacuum-chamber throat, located in its lower section, consists of separate ceramic rings connected to the metal-drawing and recirculating snorkels, located coaxially to each other and their internal refractory lining is made of many layers of ceramic blocks arranged next to each other in one circumferential line.
Once the snorkels are inserted in molten steel, liquid steel is drawn from the ladle to the vacuum chamber of the, RH unit, whereby the steel is circulated due to inert gas, preferably argon, being supplied through metal-drawing snorkel. By raising up and expanding, the inert gas pumps liquid steel into vacuum chamber through the metal- drawing snorkel, wherefrom, after its degassing, the steel returns to the ladle through the other, recirculating snorkel. Liquid steel is drawn only up to the level of the barometric pressure column which depends on external pressure and the pressure in the vacuum chamber.
The external refractory lining of snorkels, as used in known equipment for vacuum- degassing of steel, has a relatively short service life because of concrete-dissolving chemical corrosion that takes place in their service as a result of direct contact with the liquid layer of slag and having a destructive effect on the refractory lining of snorkels. In order to reduce the corrosive wear of monolithic Al2O3-base concrete layer of snorkels the concrete surface is sprayed with alkaline mass during time breaks between consecutive steel melting cycles. Thus, a layer of material that protects the concrete against direct contact with liquid slag is created.
The above mentioned snorkels have a steel casing, which holds the internal and external parts of ceramic working lining. However, in case of long times of the process and short time periods between consecutive degassings, the temperature increments of that casing after each degassing add up during the sequence and the consequential excessive rise of casing temperature leads to its significant expansion and deformation. The expansion of casing as a result of high temperature causes clearly noticeable cracks j.J „&:„„+ „,, +^1.
cooperating vacuum-chamber throat rings.
The essence of the snorkels for recirculating vacuum-degassers of steel according to this invention consists in manufacturing of metal-drawing and recirculating snorkels as well as vacuum-chamber throat rings in degassers as monolithic sets, in which ceramic blocks of the internal lining are made of several layers of rings bound together with similar overlapping blocks, with perforation being made on/in external refractory concrete lining of those monolithic sets. Favorably, the steel casings of both snorkels are provided with cooling systems, preferably gas cooling systems. Connecting the throat ring with snorkel to form a single monolith in which ceramic blocks of the external lining overlap each other has caused a significant raising of mechanical strength of those monoliths compared to separate rings of throats and snorkels with ceramic blocks arranged one next to the other in several ring-shaped layers. Making of perforation on external refractory concrete lining/surface of snorkel has enlarged the contact surface for the sprayed protective mass with concrete surface thus providing the potential for applying a thicker protective layer onto external concrete lining of snorkels for vacuum degassing of steel while ensuring also good adherence and holding of sprayed alkaline mass on the external surface of the snorkel. On the other hand, introducing of cooling system into steel casing of snorkel constituting a monolith with throat ring prevented excessive temperature increments and consequential cracks of the protective mass.
The object of his invention is shown in examples of its embodiments in the drawing where fig. 1 is a perspective view of either metal-drawing or recirculating snorkel with perforated surface of external refractory lining of the recirculating vacuum-degasser of steel, fig. 2 is a perspective view of the steel casing of the snorkel shown in fig. 1 with an arrangement of cooling pipes, and fig. 3 is a perspective view of a fragment of vacuum chamber of the recirculating vacuum-degasser of steel in axial cross-section.
The throat I of the vacuum chamber 2 of the recirculating vacuum-degasser of steel is provided with metal-drawing snorkel 3 and recirculating snorkel 4. Each of these snorkels, 3 and 4, is made as the monolith, 5 and 6, consisting of steel casing 7 with refractory lining 8_ on its external surface and a sleeve element 9 of refractory ceramic blocks iO located inside of that casing, so that the sleeve element 9 covers a set of pipes of the gas cooling system JJ, mounted on the internal surface of the steel casing 7 and projecting above its upper face by a dimension L which is equal to approx. 40 % of its total height H. Besides, external refractory lining 8 of the steel casing 7 is provided with perforation 12 all over its surface, whereas the refractory ceramic blocks H) of the sleeve element 9 are arranged alternately next to each other so that they form overlaps 1_3 with the neighboring ceramic blocks jj).
Claims
1. Snorkels of recirculating vacuum-degasser of steel installed in the lower section of the vacuum chamber of the degasser unit, one of which is the metal-drawing snorkel equipped with a duct supplying inert gas to ladle and the other is a recirculating snorkel, the lower section of said vacuum chamber being provided with chute for alloying additions, burner hole and gas-suction duct and for vacuum creation in the chamber, internal and external linings of said snorkels being held by steel casings, wherein said metal-drawing snorkel (3) and said recirculating snorkel (4) and rings of the throat (1) of said vacuum chamber (2) of said degasser unit are made as monolithic sets (5) and (6) in which ceramic blocks (10) of the internal lining are made of several layers of rings bound with each other with similar ceramic blocks overlapping each other.
2. Snorkels as claimed in Claim 1 wherein said external refractory lining (8) of said metal-drawing snorkel (3) and said recirculating snorkel (4) in both of said monolithic sets (5) and (6) are provided with perforation (12).
3. Snorkels as claimed in Claim 1 or Claim 2 wherein said steel casings (T) of said metal-drawing snorkel (3) and said recirculating snorkel (4) in both of said monolithic sets (5) and (6) are provided with cooling system (ϋ), preferably gas cooling system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP05814356A EP1957681B1 (en) | 2005-08-16 | 2005-11-21 | Snorkels for vacuum degassing of steel |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PL376633A PL204157B1 (en) | 2005-08-16 | 2005-08-16 | Connector pipes of the device for the vacuum degassing of steel |
| PLP.376633 | 2005-08-16 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2007021207A1 true WO2007021207A1 (en) | 2007-02-22 |
| WO2007021207A9 WO2007021207A9 (en) | 2007-06-28 |
Family
ID=36477709
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/PL2005/000078 WO2007021207A1 (en) | 2005-08-16 | 2005-11-21 | Snorkels for vacuum degassing of steel |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP1957681B1 (en) |
| PL (1) | PL204157B1 (en) |
| WO (1) | WO2007021207A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011023337A1 (en) * | 2009-08-28 | 2011-03-03 | Sms Siemag Aktiengesellschaft | Device for degassing molten steel with an improved discharge nozzle |
| US9038867B2 (en) | 2011-05-11 | 2015-05-26 | Tyk America, Inc. | Degasser snorkel with serpentine flow path cooling |
| US9644246B2 (en) | 2011-05-11 | 2017-05-09 | Tyk America, Inc. | Degasser snorkel with serpentine flow path cooling |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3521873A (en) * | 1966-04-28 | 1970-07-28 | Nippon Steel Corp | Passing tube for vessel for vacuum-degassing molten steel |
| BE879518A (en) * | 1979-10-19 | 1980-02-15 | Desaar Rene | PLUNGER TUBE FOR A VACUUM DEGASSING A STEEL BATH |
| JPS61253318A (en) * | 1985-05-04 | 1986-11-11 | Nippon Steel Corp | Method for cooling immersion pipe |
| US5024421A (en) * | 1990-05-08 | 1991-06-18 | Usx Corporation | Interlocking snorkel refractory |
| JPH08218113A (en) * | 1995-02-08 | 1996-08-27 | Nippon Steel Corp | Immersion pipe cooling condition setting method |
| GB2299344A (en) * | 1995-03-30 | 1996-10-02 | Veitsch Radex Ag | Snorkel for a degassing vessel |
-
2005
- 2005-08-16 PL PL376633A patent/PL204157B1/en unknown
- 2005-11-21 WO PCT/PL2005/000078 patent/WO2007021207A1/en active Application Filing
- 2005-11-21 EP EP05814356A patent/EP1957681B1/en not_active Not-in-force
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3521873A (en) * | 1966-04-28 | 1970-07-28 | Nippon Steel Corp | Passing tube for vessel for vacuum-degassing molten steel |
| BE879518A (en) * | 1979-10-19 | 1980-02-15 | Desaar Rene | PLUNGER TUBE FOR A VACUUM DEGASSING A STEEL BATH |
| JPS61253318A (en) * | 1985-05-04 | 1986-11-11 | Nippon Steel Corp | Method for cooling immersion pipe |
| US5024421A (en) * | 1990-05-08 | 1991-06-18 | Usx Corporation | Interlocking snorkel refractory |
| JPH08218113A (en) * | 1995-02-08 | 1996-08-27 | Nippon Steel Corp | Immersion pipe cooling condition setting method |
| GB2299344A (en) * | 1995-03-30 | 1996-10-02 | Veitsch Radex Ag | Snorkel for a degassing vessel |
Non-Patent Citations (3)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN vol. 011, no. 106 (C - 414) 3 April 1987 (1987-04-03) * |
| PATENT ABSTRACTS OF JAPAN vol. 1996, no. 12 26 December 1996 (1996-12-26) * |
| RATHNER R ET AL: "ENTWICKLUNG VON SPUELEMENTEN FUER ENTGASUNGSGEFAESSE. DEVELOPMENT OF PURGE ELEMENTS FOR DEGASSING UNITS", RADEX RUNDSCHAU, GRAEFELFING, DE, no. 4, December 1990 (1990-12-01), pages 365 - 376, XP002056363 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011023337A1 (en) * | 2009-08-28 | 2011-03-03 | Sms Siemag Aktiengesellschaft | Device for degassing molten steel with an improved discharge nozzle |
| RU2473704C1 (en) * | 2009-08-28 | 2013-01-27 | Смс Зимаг Акциенгезелльшафт | Device for degassing steel melt furnished with perfected exhaust sleeve |
| US9181602B2 (en) | 2009-08-28 | 2015-11-10 | Sms Group Gmbh | Device for degassing molten steel with an improved discharge nozzle |
| US9038867B2 (en) | 2011-05-11 | 2015-05-26 | Tyk America, Inc. | Degasser snorkel with serpentine flow path cooling |
| US9644246B2 (en) | 2011-05-11 | 2017-05-09 | Tyk America, Inc. | Degasser snorkel with serpentine flow path cooling |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1957681A1 (en) | 2008-08-20 |
| WO2007021207A9 (en) | 2007-06-28 |
| EP1957681B1 (en) | 2013-02-20 |
| PL376633A1 (en) | 2007-02-19 |
| PL204157B1 (en) | 2009-12-31 |
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