EP0776983B1 - Nozzle for blowing gas into molten metal and usage thereof - Google Patents
Nozzle for blowing gas into molten metal and usage thereof Download PDFInfo
- Publication number
- EP0776983B1 EP0776983B1 EP96914400A EP96914400A EP0776983B1 EP 0776983 B1 EP0776983 B1 EP 0776983B1 EP 96914400 A EP96914400 A EP 96914400A EP 96914400 A EP96914400 A EP 96914400A EP 0776983 B1 EP0776983 B1 EP 0776983B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- gas
- blast nozzle
- refractory
- gas blast
- furnace
- 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.)
- Expired - Lifetime
Links
Images
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
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- 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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/42—Constructional features of converters
- C21C5/46—Details or accessories
- C21C5/48—Bottoms or tuyéres of converters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
- B22D1/002—Treatment with gases
- B22D1/005—Injection assemblies therefor
Definitions
- This invention relates to a gas blast nozzle for molten metal in a smelting furnace such as an electric furnace or another refining furnace.
- a gas blast nozzle for molten metal that can be repaired easily, and a method of using the same.
- FIG. 5 of the accompanying drawings illustrates examples of conventional gas blast nozzles.
- Fig. 5(a), Fig. 5(b) and Fig.5(c), respectively, show a single pipe nozzle, a double pipe nozzle and a multi-pipe nozzle
- Fig. 5(d) shows a porous plug.
- reference numerals 10 and 11, respectively, denote a gas feed hose and a refractory block in a furnace bottom
- 17 and 18, respectively denote a cooling gas feed pipe and a porous brick.
- 5(c) may be realized by burying a plurality of small metal pipes in a refractory block and such a multi-pipe nozzle has been popularly used for electric furnaces because fine and evenly sized gas bubbles can be produced in molten metal by means of the multi-pipe nozzle.
- Japanese patent application laid-open publication No. 58-81937 discloses a gas blast plug comprising a refractory nozzle block having a bore therethrough and a small metal pipe placed in the bore with an annular gap to an inner surface of the bore.
- FIG. 6 of the accompanying drawings illustrates the gas blast plug according to the above prior art.
- an annular gap is formed between the inner surface of the bore and the outer surface of the small metal pipe 2, such that the thickness of the annular gap is sufficiently thin so as to avoid any leaking of molten metal.
- a gas feed hose (not shown) is connected to the small metal pipe 2.
- the arrangement shown in Fig. 6 seems to be effective for prolonging the service life of a gas blast nozzle, since the gas blast nozzle can be repaired when it has been partly worn away during its usage, and can be served for long term without replacing it.
- the inventors of the present invention have found that, when the gas blast plug according to the above is used in an electric refining furnace, the gas tends to move into the annular gap rather than entering into the molten metal as shown in Fig. 6(b).
- the gas from the small metal pipe 2 is supplied at a low rate and the gas is blown in from the bottom of the furnace, a high static pressure of the molten metal at the bottom of the furnace may resist the gas entering into the molten metal, and the gas may move more easily into the annular gap than into the molten metal.
- the above construction does not provide a solution to this problem.
- the present invention provides a gas blast nozzle that minimizes the breakdown time of a furnace for replacing the gas blast nozzle because it seldom requires the replacement, reduces the work load of the replacing operation under adverse working conditions and is free from the problem of gas leaking through the gas blast nozzle.
- Fig. 1 of the accompanying drawings shows a gas blast nozzle according to the invention.
- Fig. 1(a) is a longitudinal sectional view of the gas blast nozzle itself
- Fig. 1(b) is also a longitudinal sectional view of the gas blast nozzle showing how it is arranged in the bottom of a furnace
- Fig. 1(c) is also a longitudinal section view illustrating it with a coupler for connecting it with a gas feed hose.
- a gas blast nozzle for molten metal comprising a refractory block 4 having a narrow straight bore 3 being bored from the inside to the outside of a furnace, a tubular metal fitting 22 formed in one body with the refractory block 4, a small metal pipe 2 arranged slidably through the straight bore 3 of the refractory block 4 and a metal coupler 23 for connecting a gas hose 15 to an end of the tubular metal fitting 22, and is characterized in that an outer end portion of the small metal pipe 2 is made to penetrate through a rubber block 14 in the metal coupler 23, and the gas 12 fed to the metal coupler 23 is blown into the molten metal in the furnace from the inner end of the small metal pipe 2.
- the tubular metal fitting 22 is tubular at an end and has a saucer-like profile at the other end to snugly receive the bottom of the refractory block 4 so that the refractory block 4 is fitted and bonded to the tubular metal fitting 22 at its bottom to combine them in one body with each other. Since the refractory block 4 and the tubular metal fitting 22 are integrated in one body with each other and the small metal pipe is made to penetrate through the rubber block, gas is securely prevented from leaking through the annular gap between the small metal pipe 2 and the refractory block 4 unlike the case of Fig. 6(b).
- the tubular end of the metal fitting 22 is connected to an end of the metal coupler 23, and the other end of the metal coupler 23 is connected to a gas hose 15.
- the outer end of the small metal pipe 2 is made to penetrate the rubber block 14 and open for the gas hose 15.
- the gap between the outer periphery of the small metal pipe 2 and the inner surface of the metal coupler 23 is sealed by the rubber block 14 so that all the gas 12 fed in from the gas hose 15 is blown into the small metal pipe 2.
- a gas blast nozzle according to the invention may alternatively comprise a plurality of small metal pipes 2 in such a way that the gap between each of the small metal pipes 2 and the corresponding metal coupler 23 is filled with a rubber block 14 so that all the gas fed in may be blown into the small metal pipes 2 regardless of the number of small metal pipes 2.
- the gas blast nozzle 1 is fitted to the tuyere-forming bricks 6 at the refractory bottom 11 of the furnace and secured to an outer shell 19 of the furnace by means of a securing ring 21 and a lock member 20.
- the gap between the nozzle and the tuyere-forming bricks is filled with some castable refractory substance 5.
- the small metal pipe 2 may be a stainless steel pipe having an inner diameter of 1 to 2 mm, although the inner diameter and the number of pipes may be selected depending on the gas flow rate. Additionally, the small metal pipe may be a single pipe or a double pipe. It should be noted that the inner diameter of the straight bore 3 is made greater than the outer diameter of the small metal pipe 2 by 0 to 4 mm in order to allow the small metal pipe 2 to move smoothly vertically.
- FIG. 2 illustrates a method of using the gas blast nozzle 1 according to the invention.
- a gas blast nozzle 1 according to the invention is worn away, in particular the inner refractory is worn away during its usage which produces a worn away portion 8 as shown in Fig. 2(a).
- the worn away portion 8 is repaired by moving upward the small metal pipe 2 in the straight bore 3 until the inner end of the small metal pipe 2 projects over the inner surface of the furnace as shown in Fig. 2(b).
- the worn away portion 8 is filled with a refractory material 16 without closing the inner end of the small metal pipe 2 as shown in Fig. 2(c).
- the inner end of the small metal pipe 2 is projecting over the inner surface of the furnace after the worn away portion has been filled with the refractory material 16.
- the inner end of the small metal pipe 2 would neither be buried nor clogged by this projection even if in a usual repairing apparatus of the furnace a lining such as a sand slinger is used to fill the worn away portion 8 with an ordinary refractory material for repairing the lining of the furnace.
- the gas blast nozzle and its peripheral area can be repaired easily, if necessary, in the routine operation for maintaining the furnace bottom and the furnace wall, which consequently prolongs the service life of the gas blast nozzle so that the frequency of replacing the gas blast nozzle will be remarkably reduced.
- the projecting portion of the small metal pipe 2 is immediately molten away and the inner end of the gas blast nozzle will show a profile as shown in Fig. 1(b). Also, the gas blast nozzle operates to blow gas into the molten metal as stably as before.
- Fig. 3 illustrates another embodiment of a gas blast nozzle according to the invention.
- Fig. 3(a) is a longitudinal sectional view of the gas blast nozzle and
- Fig. 3(b) is also a longitudinal sectional view showing how the gas blast nozzle is arranged in the bottom of a furnace.
- the gas blast nozzle of Fig. 3(a) differs from that of Fig. 1(a) in that the refractory block 4 is divided into upper and lower pieces. Otherwise, it is the same as its counterpart of Fig. 1(a).
- the tubular metal fitting 22 is coupled at its outer end to a gas hose 15 by means of a metal coupler 23 and the annular gap around the small metal pipe 2 is sealed by a rubber block 14.
- the gas blast nozzle is also fitted to the tuyere-forming bricks 6 at the refractory bottom 11 of the furnace and secured to the outer shell 19 of the furnace by means of a securing ring 21 and a lock member 20. Also, the gap between the nozzle and the tuyere-forming bricks is filled with some castable refractory substance.
- Fig. 4 illustrates a method of using the gas blast nozzle illustrated in Fig. 3.
- the worn away portion 8 in Fig. 4(a) is repaired by moving upward the small metal pipe 2 in the straight bore until the inner end of the small metal pipe 2 projects over the inner surface of the furnace, replacing the damaged upper piece 4a of the refractory block with a new upper piece 4a (hereinafter referred to as a repairing brick) as shown in Fig. 4(b) and filling the remaining portion with a refractory material 16. Thereafter, the small metal pipe 2 is moved downward until the inner end arrives at the same level as that of the upper surface of the repairing brick 4a.
- the service life of the gas blast nozzle will be further prolonged compared with its repairing where the worn away portion is filled only by a castable refractory material. Additionally, since the small metal pipe 2 is not projecting into the furnace after repairing, it will be consumed at a reduced rate.
- a straight bore having an inner diameter of 5 mm was formed through a refractory block 4 as shown in Fig. 1(a) in order to provide a gas blast nozzle for feeding gas from the bottom of an electric furnace.
- the small metal pipe 2 had an inner diameter of 2 mm, an outer diameter of 4 mm and a length of 2 m and was used with a metal coupler 23 as shown in Fig. 1(c).
- Gas was blown into the molten metal in the furnace at a rate of 30 to 100 liter/min.
- the gas feeding hose 15 as shown in Fig. 1(c) was removed, the small metal pipe 2 was moved upward until the upper end arrived at the same level as that of the surface of a repaired refractory bottom 11 of the furnace and the worn away portion was filled with refractory material. After this repairing, it was coupled with the gas hose 15 again by means of the metal coupler 23.
- An ordinary refractory material for repairing furnace bottom was used to fill the worn away portion of the furnace.
- gas was continuously blown during the operation of filling the refractory material.
- the small metal pipe 2 was replaced by a new one, and the cycle of usual furnace operation and repairing was further repeated.
- moving and/or replacing the small metal pipe 2 it was found in some cases that molten metal had entered into the annular gap between the straight bore 3 and the metal pipe 2 and been solidified there.
- the small metal pipe 2 could be easily moved by striking it from the underside.
- the gas blast nozzle 1 was replaced when the worn away portion 8 of the nozzle became as deep as 300 mm, and it was found that the gas blast nozzle 1 according to the invention can withstand more than 300 charges, showing a remarkable improvement in the service life when compared with conventional gas blast nozzles that were replaced at every 50 charges.
- Case 1 in Table 1 represents the use of a split type gas blast nozzle as shown in Fig. 3 which was repaired by using a repairing brick 4a and filling refractory material.
- the upper piece of refractory block 4a was removed and the small metal pipe 2 was moved upwards. Thereafter, a new upper piece of refractory block 4a was connected to the lower piece of refractory block 4b with power applied therebetween.
- the annular gap between the small metal pipe 2 and the straight bore 3 of the refractory block was also filled with a nonporous refractory material.
- the worn away portion was filled with a filling material to complete the first repair.
- the gas blast nozzle was repaired after every 170 to 200 operating hours for the second through fifth repairs.
- the (upper) tuyere-forming brick 6 was also replaced at the even-numbered repairs.
- the upper piece of refractory block 4a had an orginal length of 200 mm, although the remaining length was between 50 and 100 mm at the time of each repair.
- the nozzle was replaced 170 to 200 hours after the fifth repair, then the lower piece of refractory block 4b was undamaged and could be used further.
- Case 2 in Table 1 represents the use of a one piece nozzle as shown in Fig. 1, which was repaired only by means of a filling refractory material. After 170 to 200 hours of gas blast operation, the small metal pipe 2 was moved upwards by a length greater than the height of the worn away portion of the nozzle, and the worn away portion was filled with a filling refractory material.
- the gas blast nozzle was repaired after every 80 to 100 operating hours for the second and fourth repairs.
- the nozzle had been worn away by 250 to 300 mm, and along with the upper tuyere-forming bricks they were replaced by the new ones, because they were so damaged that the time required for further repairing seemed to exceed the specified repairing time.
- the gas blast nozzle according to the invention can reduce the frequency of replacement of the gas blast nozzle, and can reduce the breakdown time of the furnace operation. Additionally, it reduces the work load of the replacing operation under adverse working conditions and is free from the problem of gas leaking through the gas blast nozzle.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Description
- Fig. 1
- illustrates an embodiment of a gas blast nozzle according to the invention.
- Fig. 2
- illustrates a method of using the gas blast nozzle of Fig. 1.
- Fig. 3
- illustrates another embodiment of a gas blast nozzle according to the invention.
- Fig. 4
- illustrates the method of using the gas blast nozzle of Fig. 3.
- Fig. 5
- illustrates a conventional gas blast nozzle.
- Fig. 6
- illustrates a conventional gas blast plug.
Case | 1 | 2 |
Type of nozzle | Two piece type (FIG. 3) | One piece type (FIG. 1) |
Repairing method | Using repairing brick (4a) and filling refractory | Using only filling refractory |
Service life from replacement to the 1st repair | 170 - 200 (h) | 170 - 200 (h) |
Service life from repairing to the next repairing | 170 - 200 (h) | 80 - 100 (h) |
Number of repairing from replacement to the | 5 | 4 times |
Service life from replacement to the next replacement | 1150 (h) | 550 (h) |
- 1:
- Gas blast nozzle for molten metal
- 2:
- Small metal pipe
- 3:
- Straight bore
- 4:
- Refractory block
- 5:
- Castable refractory substance
- 6:
- Tuyere-forming brick
- 8:
- Worn away portion
- 10:
- Gas feed hose
- 11:
- Refractory bottom of a furnace
- 12:
- Gas
- 14:
- Rubber block
- 15:
- Gas feed hose
- 16:
- Repairing refractory material
- 17:
- Cooling gas feed pipe
- 18:
- Porous brick
- 19:
- Outer shell of a furnace
- 20:
- Lock member
- 21:
- Securing ring
- 22:
- Tubular metal fitting
- 23:
- Metal coupler
Claims (4)
- A gas blast nozzle for molten metal comprisinga refractory block (4) having a narrow straight bore (3) being bored from the inside to the outside of a furnace,a tubular metal fitting (22) formed in one body with the refractory block (4),a small metal pipe (2) arranged slidably through the straight bore (3), anda metal coupler (23) for connecting a gas hose (15) to an end of the tubular metal fitting (22),
- A method of using a gas blast nozzle for molten metal as defined in claim 1,
characterized in that, in repairing a worn away inner portion (8) of the gas blast nozzle and a surrounding area, a refractory material is filled into the worn away portion (8) after having moved the small metal pipe (2) upwards through the straight bore (3) so that its inner end projects over the inner surface of the furnace in order to prevent its inner end from being clogged by a refractory material. - A gas blast nozzle for molten metal according to claim 1, characterized in that the refractory block (4) is composed by two or more refractory pieces being piled vertically.
- A method of using a gas blast nozzle for molten metal as defined in claim 3,
characterized in that, in repairing a worn away inner portion (8) of the gas blast nozzle and a surrounding area, the used upper refractory piece (4a) is changed to a new upper refractory piece (4a), and a refractory material is filled into the worn away portion (8) after moving the small metal pipe (2) upwards through the straight bore (3) so that its inner end projects over the inner surface of the furnace in order to prevent its upper end from being clogged by a refractory material.
Applications Claiming Priority (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12610795 | 1995-05-25 | ||
JP12610795 | 1995-05-25 | ||
JP126107/95 | 1995-05-25 | ||
JP32444795 | 1995-12-13 | ||
JP7324447A JPH0941024A (en) | 1995-05-25 | 1995-12-13 | Gas blowing nozzle into molten metal and its using method thereof |
JP324447/95 | 1995-12-13 | ||
PCT/JP1996/001356 WO1996037632A1 (en) | 1995-05-25 | 1996-05-23 | Nozzle for blowing gas into molten metal and usage thereof |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0776983A1 EP0776983A1 (en) | 1997-06-04 |
EP0776983A4 EP0776983A4 (en) | 1998-09-09 |
EP0776983B1 true EP0776983B1 (en) | 2001-09-26 |
Family
ID=26462336
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96914400A Expired - Lifetime EP0776983B1 (en) | 1995-05-25 | 1996-05-23 | Nozzle for blowing gas into molten metal and usage thereof |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0776983B1 (en) |
JP (2) | JPH0941024A (en) |
KR (1) | KR100349870B1 (en) |
CN (1) | CN1053015C (en) |
CA (1) | CA2195541A1 (en) |
DE (1) | DE69615508T2 (en) |
WO (1) | WO1996037632A1 (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10347947B4 (en) * | 2003-10-15 | 2007-04-12 | Maerz-Gautschi Industrieofenanlagen Gmbh | Industrial furnace and associated nozzle element |
JP4351715B2 (en) * | 2007-09-10 | 2009-10-28 | 新日本製鐵株式会社 | Tuna structure of melting furnace |
KR101310737B1 (en) * | 2008-07-28 | 2013-09-25 | 신닛테츠스미킨 카부시키카이샤 | Nozzle for continuous casting |
PL2942406T3 (en) * | 2014-05-05 | 2016-08-31 | Refractory Intellectual Property Gmbh & Co Kg | Fire resistant ceramic gas flushing element |
ES2685248T3 (en) * | 2014-09-29 | 2018-10-08 | Refractory Intellectual Property Gmbh & Co. Kg | Fixing device for a cylindrical ceramic hollow body and a refractory ceramic gas purge plug with such a fixing device |
EP3290532B1 (en) * | 2015-12-17 | 2020-05-06 | TYK Corporation | Converter furnace with bottom-blowing plug with improved workability |
JP7107141B2 (en) * | 2018-09-27 | 2022-07-27 | 日本製鉄株式会社 | Converter tuyere structure |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5952216B2 (en) * | 1979-05-24 | 1984-12-18 | 住友金属工業株式会社 | How to replace the gas blowing nozzle |
JPS5881937A (en) * | 1981-11-12 | 1983-05-17 | Kawasaki Steel Corp | Plug for injecting refining gas |
JPS5952216A (en) * | 1982-09-20 | 1984-03-26 | Canon Inc | Plural beam optical deflector |
DE3311617C1 (en) * | 1983-03-30 | 1984-10-25 | Messer Griesheim Gmbh, 6000 Frankfurt | Method and device for rinsing a molten metal, in particular steel, in a ladle |
JPS6030834A (en) * | 1983-07-14 | 1985-02-16 | Fuji Electric Co Ltd | Disk brake device |
DE3545763A1 (en) * | 1985-12-21 | 1987-06-25 | Didier Werke Ag | GAS PUMP PLUG FOR A MELTING VESSEL |
JPS6489947A (en) * | 1987-09-30 | 1989-04-05 | Aisin Seiki | Generating set for vehicle |
JPH0630834Y2 (en) * | 1987-12-07 | 1994-08-17 | 川崎炉材株式会社 | Gas blown tuyere structure for molten metal containers |
JPH01172507A (en) * | 1987-12-28 | 1989-07-07 | Nippon Steel Corp | Construction for fitting triple pie tuyere to furnace bottom |
JPH0497835U (en) * | 1991-01-11 | 1992-08-25 | ||
DE4213007C1 (en) * | 1992-04-21 | 1993-12-16 | Tech Resources Pty Ltd | Method and device for sealing nozzles in the surrounding refractory lining |
JP4610946B2 (en) * | 2004-06-30 | 2011-01-12 | 株式会社島津製作所 | Odor identification method |
-
1995
- 1995-12-13 JP JP7324447A patent/JPH0941024A/en active Pending
-
1996
- 1996-05-23 DE DE69615508T patent/DE69615508T2/en not_active Expired - Fee Related
- 1996-05-23 CN CN96190548A patent/CN1053015C/en not_active Expired - Fee Related
- 1996-05-23 KR KR1019970700435A patent/KR100349870B1/en not_active IP Right Cessation
- 1996-05-23 EP EP96914400A patent/EP0776983B1/en not_active Expired - Lifetime
- 1996-05-23 CA CA002195541A patent/CA2195541A1/en not_active Abandoned
- 1996-05-23 JP JP53555896A patent/JP3894502B2/en not_active Expired - Lifetime
- 1996-05-23 WO PCT/JP1996/001356 patent/WO1996037632A1/en active IP Right Grant
Also Published As
Publication number | Publication date |
---|---|
EP0776983A4 (en) | 1998-09-09 |
DE69615508T2 (en) | 2002-05-29 |
CA2195541A1 (en) | 1996-11-28 |
DE69615508D1 (en) | 2001-10-31 |
JP3894502B2 (en) | 2007-03-22 |
KR100349870B1 (en) | 2003-01-06 |
CN1154720A (en) | 1997-07-16 |
EP0776983A1 (en) | 1997-06-04 |
KR970704892A (en) | 1997-09-06 |
JPH0941024A (en) | 1997-02-10 |
CN1053015C (en) | 2000-05-31 |
WO1996037632A1 (en) | 1996-11-28 |
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