CA2078640A1 - Electric arc furnace bottom stir tuyere assembly - Google Patents
Electric arc furnace bottom stir tuyere assemblyInfo
- Publication number
- CA2078640A1 CA2078640A1 CA002078640A CA2078640A CA2078640A1 CA 2078640 A1 CA2078640 A1 CA 2078640A1 CA 002078640 A CA002078640 A CA 002078640A CA 2078640 A CA2078640 A CA 2078640A CA 2078640 A1 CA2078640 A1 CA 2078640A1
- Authority
- CA
- Canada
- Prior art keywords
- tuyere
- furnace
- hearth
- gas
- melt
- 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.)
- Abandoned
Links
Classifications
-
- 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
-
- 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
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/5211—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace
- C21C5/5217—Manufacture of steel in electric furnaces in an alternating current [AC] electric arc furnace equipped with burners or devices for injecting gas, i.e. oxygen, or pulverulent materials into the furnace
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
- F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces heated electrically, with or without any other source of heat
- F27B3/085—Arc furnaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D1/00—Casings; Linings; Walls; Roofs
- F27D1/16—Making or repairing linings increasing the durability of linings or breaking away linings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
ABSTRACT
A tuyere for injecting gas for stirring the melt in an electric arc furnace; in which as initially installed the tuyere extends a substantial distance above the furnace lining so as to avoid erosion of the lining by the currents produced in the melt by the stirring gas.
A tuyere for injecting gas for stirring the melt in an electric arc furnace; in which as initially installed the tuyere extends a substantial distance above the furnace lining so as to avoid erosion of the lining by the currents produced in the melt by the stirring gas.
Description
2~7~6~
ELECTRIC ARC FURNACE BOTTOM STIR TUYERE ASSEMBLY
FIE~D OF THE INVENTION
Thls ~nventlon relates to an lmproved means for stlrr~ng the contents of an electrlc arc furnace.
BACKGRW ND OF THE I~VENT12~
Var~ous means have been proposed for stlrr~ng the molten metal con-tatned in electrtc arc furnaces. In general these fall lnto two maln groups namely: dev~ces which utlllze magnetlc or electromagnet~c means to c~rculate the molten metal and dev~ces ln whlch gas ~s ~ntroduced lnto the furnace through a tuyere or other gas ln~ectlon dev~ce.
The use of magnet~c or electromagnetlc st1rr~ng dev~ces requlres expenstve and complex addlt~onal equ1pment and Is undes7rable from a cost standpo~nt. Tuyeres or lances lr~stalled ~n the furnace lln~ng produce the desired agitat~on however the stlrrlng campa~gn ls typlcally less than desired due to molten metal penetrat~on and/or the format~on of a metal/
15 slag/refractory crust above the tuyere. When the gas flow passage ls sufflclently large such that the pressure of the gas ex1tlng the tuyere does not exceed the local pressure due to the welght of the metal bath gas bubbles form and release at ~he tuyere tlp. ~lth the release of each bubble molten metal penetrates and solld~f~es lnslde the tuyere untll the passage is elther completely blocked (requ~rlng oxygen blowlng to reopen) or has formed a restr~ctlon whlch enables h~ghly unstable continuous flow at a threshold son~c velocity. Th~s flow reg1me has been referred to as ~nclptent ~ett~ng and ~s bel~eved to cause rap~d eros~on o~ the local re~ractory as d~scussed ~n a paper entltled Gas In~ect~on Tuvere Des~gn and Exper~ence by L. Farmer D. Lach M. Lanyl and D. ~nchester publlshed in the 1989 Steelmaking Conference Proceed~ng pp.487-495 by ISS-AIME. When a sump or depresslon develops around a tuyere due to local eroslon and/or hearth repalr the tuyere ls prone to be~ng covered by crust cons~stlng of one or more of the following: metal slag refractory repa~r materlal. Once 3~
~07~6~0 covered there ~s no v~slble slgn of stlrrlng and presumably no beneflts of stlrring are derlved dur~ng thls perlod. Thls condlt10n cont~nues untll the crust ls melted away allowlng stlrr~ng to resu~e. Thls lntermittent stlrrlng ls hlghly unpred1ctable and therefore undes~rable for cons1stent s operatlon.
SUMMARY OF THE INVE~II
The present lnventlon provldes a means for avo~d1ng the expens~ o~
lnstalllng electromagnetlc stlrr~ng means and for avoldlng the lnter~lttent blockage ~hlch has been experleneed wlth prlor art gas ln~ectlon devlces lnstalled ln the furnace llnlng.
The ~nventlon provldes an lmproved means for 1n~ectlng gas ~nto an electrlc arc furnace whlch avolds the formatlon of a sump or plt when gas ls ln~ected lnto the melt and ln whlch an open passageway for the lntroductlon of gas 1nto the melt ls avallable at all tlmes.
The 1nventlon also provldes gas ln~ectlon means whlch ls readlly lnstalled ln a furnace bottom and whlch has a long servlce l~fe.
3RIEF DESU~L~L~LOF T~E DRAWING
20Flgure l ls a fragmentary cross-sect10n of a furnace wlth a tuyere constructed ~n accordance w1th the present ln~ent10n;
Flgure 2 ls an enlar~ed fragmentary vl~w of the tuyere of Flgure l and Flgures 3(a) to 3(e) lllustrate one posslble ~echanlsm whlch may cause lntermlttent loss of stlrrlng ln prlor art devlces.
2s PETAILED DESCRI
As shown schematlcally ~n Flgure 3(a) a pr~or art st~rr~ng devlce or tuyere compr1ses a gas ~n~ect~ng p~pe 1 embedded ln a refractory sleeve 2 set ln refractory brlcks 3 and a refractory l~nlng 4. As ~ns~alled the tuyere l 2 ls flush wlth the top of the lln~ng 4 and when the tuyere ~s flrst ~nstalled good st~rrlng occurs when gas ls fed through the p~pe l. As success~ve heats are melted ln the furnace a comblnatlon of loose refractory materlal falllng lnto the area of the tuyere dur~ng furnace repa~r between heats and eros~on ln the area ad~acent to the ex~t tlp 5 of plpe l posslbly due to the currents set ln motlon as the metal ~s stlrred by the gas ~n~ected through plpe l results ln the cond~t10n shown ln F~g.
3(b).
20 ~86~0 Between heats the l~nlng ls repa~red e.g., by shovelllng or gunnlng loose refractory onto the furnace hearth or bottom, and thls refractory plus any restdual molten metal or slag ~n the furnace can form a crust 6 and produce the condltlon shown ~n F~gure 3~c). Thls blocks the exlt from plpe S l and no st1rrlng occurs untll an open~ng 7 ~s created e.g., e~ther by permlttlng the heat suppl~ed to the furnace to cause remeltlng o~ the crust 6, as shown-ln F~gure 3(d), or oxygQn can be lntroduced into plpQ l to open a passage through the crust 6.
Eventually the b~ockage becomes more severe, e.g., because of a skull 8 of metal be1ng formed on top of the crust 6. Th~s condlt10n ~s shown ~n Flgure 3(e). As the blockage progresses there ls no lndlcatlon of a problem because gas cont1nues to flow through the p~pe l and the back pressure does not elevate unt~l the lnlt~ally porous skull 8 becomes dense. It was observed that once the blockage occurred, the gas would flow but stlrr~ng of the metal could not be observed and therefore lt 1s bel1eved that the gas was not st1rrtng the melt poss~bly becaus~ lt was enter1ng the furnace over an extenslve area through w~dely d~spersed cracks, f~ssures, and pores.
To avold thls sequence of events the present lnventlon provldes a tuyere shown ln F~gures l and 2. As shown ln Flgure l, a furnace lO hav1ng a llnlng 12 of refractory brlck as 1s well known ln the art has a hearth 14 of refractory materlal wh~ch may be rammed 1n place. Furnace lO may also lnclude rammed refractory base 16 for the br1ck work 12. Accordlng to the ~nventlon, a tuyere assembly 18 ls posltloned tn the bottom of furnace lO
with a portlon projectlng above the hearth 14. Re~errtng to Flgure 2 the tuyere assembly 18 ~ncludes a chrome magnes~te tuyere block 20 hav~ng a cross-sect~onal shape ln the form of a trapezo~d set 7n the l~nlng or hearth 14 as the remalnder of the 11nlng ~s la~d down on the furnace hearth.
Tuyere block 20 ls so constructed and arranged to recelve a tuyere br~ck 22 made from a refractory mater~al (e.g., MgO-Graphlte m~xture) su~table for belng formed around the small d~ameter stalnless steel tubular nozzle p~pe 24. Nozzle p~pe 24 ls ~n turn connected to a larger dlameter gas supply plpe 26 as by a clrcumferent~al weld 28 at the upper end 30 of supply plpe 26. Thls construction ls deslgned so that when the tuyere brlck 22 erodes or the nozzle p~pe 24 becomes blocked and can not be cleared ~ ~ 7 ~
by oxygen ln~ectlon or there ls a routlne change of the tuyere the tuyere brlck 22 nozzle and p1pe assembly 24-32 may be removed easlly from the furnace by pushlng on the lower end 32 of the supply plpe 26 to move tuyere brlck 22 and nozzle and plpe assembly 2~-32 upwardly lnto the ~urnace hearth area. A new nozzle and plpe assembly ls then lnstalled by lnsert1ng a new tuyere brlck 22 and plpe asse~bly 24-32 lnto the openlng created by removal of the used assembly from lnslde the furnace. Tuyere brlck 22 and alter-nately tuyere block 20 and tuyere br~ck 22 lnltl~lly extend approxlmate1y at least one lnch and pre~erably four lnches above the hearth llnlng 14 to opttm~ze the mass of block 20 pro~ect1ng above hearth 14. The lower end 32 of supply 26 ls adapted for connectlon to a source of stlrrlng gas such as argon or other lnert gas by conventlonal flexlble hose connectlon as known ln the art and therefore not shown.
As shown ln F~gures 1 and 2 tuyere brlck 22 ls lnstalled so lts top extends above the top surface of the hearth 14 a dlstance of two (2) to four (4) lnches. Based upon a wear rate of about .02 inches (0.5 mm) per heat the tuyere of the lnvent10n wlll survlve for more than 100 heats. When the tuyere br~ck 22 erodes or the hearth l~nlng surface 14 bu11ds up so that ~t ls now flush w~th the top surface of the tuyere br1ck 22 the tuyere brlck 22 and nozle and ptpe assembly 24-32 should be replaced. As a result of thls construct~on sump format~on ~s avolded and a contlnuous flow of st~rrlng gas has been found to be lnsured.
Add~tlonally the tuyere open1ng ~s slzed to operate such that the gas ex~ts the tuyere as an underexpanded ~et. In thls mode the gas pressure upon exltlng the tuyere exceeds the local pressure due to the welght of the llqu1d metal. Upon ex~tlng the tuyere the gas w111 accelerate as ~t expands to the local pressure. The tuyere ls des~gned so that the gas veloclty at the tuyere exlt ls son1c (Mach No. 1.0) and upon expandlng outs~de of the tuyere supersonlc velocltles are attalned (Mach No. > 1.0).
Our stud1es have shown that at fully expanded velocltles greater than Mach No. a 1.25 a very stable ~et ls produced and the degree of local eroslon ls m~nimlzed.
Employlng an elevated tuyere accord~ng to the lnventlon wlll enable steady and cont~nuous operatlon of sufflclent duratlon.
2~78~
Hav1ng now descr1bed the 1nvent1On 1t 1s not 1ntended that 1t be 11m1ted except as may b0 requ1red by the appended cla1ms.
ELECTRIC ARC FURNACE BOTTOM STIR TUYERE ASSEMBLY
FIE~D OF THE INVENTION
Thls ~nventlon relates to an lmproved means for stlrr~ng the contents of an electrlc arc furnace.
BACKGRW ND OF THE I~VENT12~
Var~ous means have been proposed for stlrr~ng the molten metal con-tatned in electrtc arc furnaces. In general these fall lnto two maln groups namely: dev~ces which utlllze magnetlc or electromagnet~c means to c~rculate the molten metal and dev~ces ln whlch gas ~s ~ntroduced lnto the furnace through a tuyere or other gas ln~ectlon dev~ce.
The use of magnet~c or electromagnetlc st1rr~ng dev~ces requlres expenstve and complex addlt~onal equ1pment and Is undes7rable from a cost standpo~nt. Tuyeres or lances lr~stalled ~n the furnace lln~ng produce the desired agitat~on however the stlrrlng campa~gn ls typlcally less than desired due to molten metal penetrat~on and/or the format~on of a metal/
15 slag/refractory crust above the tuyere. When the gas flow passage ls sufflclently large such that the pressure of the gas ex1tlng the tuyere does not exceed the local pressure due to the welght of the metal bath gas bubbles form and release at ~he tuyere tlp. ~lth the release of each bubble molten metal penetrates and solld~f~es lnslde the tuyere untll the passage is elther completely blocked (requ~rlng oxygen blowlng to reopen) or has formed a restr~ctlon whlch enables h~ghly unstable continuous flow at a threshold son~c velocity. Th~s flow reg1me has been referred to as ~nclptent ~ett~ng and ~s bel~eved to cause rap~d eros~on o~ the local re~ractory as d~scussed ~n a paper entltled Gas In~ect~on Tuvere Des~gn and Exper~ence by L. Farmer D. Lach M. Lanyl and D. ~nchester publlshed in the 1989 Steelmaking Conference Proceed~ng pp.487-495 by ISS-AIME. When a sump or depresslon develops around a tuyere due to local eroslon and/or hearth repalr the tuyere ls prone to be~ng covered by crust cons~stlng of one or more of the following: metal slag refractory repa~r materlal. Once 3~
~07~6~0 covered there ~s no v~slble slgn of stlrrlng and presumably no beneflts of stlrring are derlved dur~ng thls perlod. Thls condlt10n cont~nues untll the crust ls melted away allowlng stlrr~ng to resu~e. Thls lntermittent stlrrlng ls hlghly unpred1ctable and therefore undes~rable for cons1stent s operatlon.
SUMMARY OF THE INVE~II
The present lnventlon provldes a means for avo~d1ng the expens~ o~
lnstalllng electromagnetlc stlrr~ng means and for avoldlng the lnter~lttent blockage ~hlch has been experleneed wlth prlor art gas ln~ectlon devlces lnstalled ln the furnace llnlng.
The ~nventlon provldes an lmproved means for 1n~ectlng gas ~nto an electrlc arc furnace whlch avolds the formatlon of a sump or plt when gas ls ln~ected lnto the melt and ln whlch an open passageway for the lntroductlon of gas 1nto the melt ls avallable at all tlmes.
The 1nventlon also provldes gas ln~ectlon means whlch ls readlly lnstalled ln a furnace bottom and whlch has a long servlce l~fe.
3RIEF DESU~L~L~LOF T~E DRAWING
20Flgure l ls a fragmentary cross-sect10n of a furnace wlth a tuyere constructed ~n accordance w1th the present ln~ent10n;
Flgure 2 ls an enlar~ed fragmentary vl~w of the tuyere of Flgure l and Flgures 3(a) to 3(e) lllustrate one posslble ~echanlsm whlch may cause lntermlttent loss of stlrrlng ln prlor art devlces.
2s PETAILED DESCRI
As shown schematlcally ~n Flgure 3(a) a pr~or art st~rr~ng devlce or tuyere compr1ses a gas ~n~ect~ng p~pe 1 embedded ln a refractory sleeve 2 set ln refractory brlcks 3 and a refractory l~nlng 4. As ~ns~alled the tuyere l 2 ls flush wlth the top of the lln~ng 4 and when the tuyere ~s flrst ~nstalled good st~rrlng occurs when gas ls fed through the p~pe l. As success~ve heats are melted ln the furnace a comblnatlon of loose refractory materlal falllng lnto the area of the tuyere dur~ng furnace repa~r between heats and eros~on ln the area ad~acent to the ex~t tlp 5 of plpe l posslbly due to the currents set ln motlon as the metal ~s stlrred by the gas ~n~ected through plpe l results ln the cond~t10n shown ln F~g.
3(b).
20 ~86~0 Between heats the l~nlng ls repa~red e.g., by shovelllng or gunnlng loose refractory onto the furnace hearth or bottom, and thls refractory plus any restdual molten metal or slag ~n the furnace can form a crust 6 and produce the condltlon shown ~n F~gure 3~c). Thls blocks the exlt from plpe S l and no st1rrlng occurs untll an open~ng 7 ~s created e.g., e~ther by permlttlng the heat suppl~ed to the furnace to cause remeltlng o~ the crust 6, as shown-ln F~gure 3(d), or oxygQn can be lntroduced into plpQ l to open a passage through the crust 6.
Eventually the b~ockage becomes more severe, e.g., because of a skull 8 of metal be1ng formed on top of the crust 6. Th~s condlt10n ~s shown ~n Flgure 3(e). As the blockage progresses there ls no lndlcatlon of a problem because gas cont1nues to flow through the p~pe l and the back pressure does not elevate unt~l the lnlt~ally porous skull 8 becomes dense. It was observed that once the blockage occurred, the gas would flow but stlrr~ng of the metal could not be observed and therefore lt 1s bel1eved that the gas was not st1rrtng the melt poss~bly becaus~ lt was enter1ng the furnace over an extenslve area through w~dely d~spersed cracks, f~ssures, and pores.
To avold thls sequence of events the present lnventlon provldes a tuyere shown ln F~gures l and 2. As shown ln Flgure l, a furnace lO hav1ng a llnlng 12 of refractory brlck as 1s well known ln the art has a hearth 14 of refractory materlal wh~ch may be rammed 1n place. Furnace lO may also lnclude rammed refractory base 16 for the br1ck work 12. Accordlng to the ~nventlon, a tuyere assembly 18 ls posltloned tn the bottom of furnace lO
with a portlon projectlng above the hearth 14. Re~errtng to Flgure 2 the tuyere assembly 18 ~ncludes a chrome magnes~te tuyere block 20 hav~ng a cross-sect~onal shape ln the form of a trapezo~d set 7n the l~nlng or hearth 14 as the remalnder of the 11nlng ~s la~d down on the furnace hearth.
Tuyere block 20 ls so constructed and arranged to recelve a tuyere br~ck 22 made from a refractory mater~al (e.g., MgO-Graphlte m~xture) su~table for belng formed around the small d~ameter stalnless steel tubular nozzle p~pe 24. Nozzle p~pe 24 ls ~n turn connected to a larger dlameter gas supply plpe 26 as by a clrcumferent~al weld 28 at the upper end 30 of supply plpe 26. Thls construction ls deslgned so that when the tuyere brlck 22 erodes or the nozzle p~pe 24 becomes blocked and can not be cleared ~ ~ 7 ~
by oxygen ln~ectlon or there ls a routlne change of the tuyere the tuyere brlck 22 nozzle and p1pe assembly 24-32 may be removed easlly from the furnace by pushlng on the lower end 32 of the supply plpe 26 to move tuyere brlck 22 and nozzle and plpe assembly 2~-32 upwardly lnto the ~urnace hearth area. A new nozzle and plpe assembly ls then lnstalled by lnsert1ng a new tuyere brlck 22 and plpe asse~bly 24-32 lnto the openlng created by removal of the used assembly from lnslde the furnace. Tuyere brlck 22 and alter-nately tuyere block 20 and tuyere br~ck 22 lnltl~lly extend approxlmate1y at least one lnch and pre~erably four lnches above the hearth llnlng 14 to opttm~ze the mass of block 20 pro~ect1ng above hearth 14. The lower end 32 of supply 26 ls adapted for connectlon to a source of stlrrlng gas such as argon or other lnert gas by conventlonal flexlble hose connectlon as known ln the art and therefore not shown.
As shown ln F~gures 1 and 2 tuyere brlck 22 ls lnstalled so lts top extends above the top surface of the hearth 14 a dlstance of two (2) to four (4) lnches. Based upon a wear rate of about .02 inches (0.5 mm) per heat the tuyere of the lnvent10n wlll survlve for more than 100 heats. When the tuyere br~ck 22 erodes or the hearth l~nlng surface 14 bu11ds up so that ~t ls now flush w~th the top surface of the tuyere br1ck 22 the tuyere brlck 22 and nozle and ptpe assembly 24-32 should be replaced. As a result of thls construct~on sump format~on ~s avolded and a contlnuous flow of st~rrlng gas has been found to be lnsured.
Add~tlonally the tuyere open1ng ~s slzed to operate such that the gas ex~ts the tuyere as an underexpanded ~et. In thls mode the gas pressure upon exltlng the tuyere exceeds the local pressure due to the welght of the llqu1d metal. Upon ex~tlng the tuyere the gas w111 accelerate as ~t expands to the local pressure. The tuyere ls des~gned so that the gas veloclty at the tuyere exlt ls son1c (Mach No. 1.0) and upon expandlng outs~de of the tuyere supersonlc velocltles are attalned (Mach No. > 1.0).
Our stud1es have shown that at fully expanded velocltles greater than Mach No. a 1.25 a very stable ~et ls produced and the degree of local eroslon ls m~nimlzed.
Employlng an elevated tuyere accord~ng to the lnventlon wlll enable steady and cont~nuous operatlon of sufflclent duratlon.
2~78~
Hav1ng now descr1bed the 1nvent1On 1t 1s not 1ntended that 1t be 11m1ted except as may b0 requ1red by the appended cla1ms.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In an electric arc furnace which includes a refractory lined bottom, the improvement which comprises at least one tuyere assembly set in said bottom so that it extends a sufficient distance above the bottom to avoid erosion of said bottom when a stirring gas is introduced into said furnace through a pipe in said tuyere assembly.
2. The apparatus of Claim 1, in which sand tuyere assembly extends approximately at least one inch above said refractory lined bottom.
3. The apparatus of Claim 2 in which said tuyere assembly extends a distance between approximately one inch and four inches above said refractory furnace bottom at the time it is originally installed.
4. In a method of melting metal in an electric arc furnace having a refractory lined hearth in which said furnace is charged with metal and a melt is formed in said furnace hearth the improvement which comprises stirring said melt by introducing a stirring gas into said melt through a conduit disposed in a tuyere assembly located in the refractory lining in the hearth and extending above said hearth said conduit extending from outside said furnace through said hearth and said tuyere assembly.
5. A method according to Claim 4 wherein said tuyere block extends approximately at least one inch above said hearth.
6. A method according to Claim 5 wherein said tuyere block extends a distance between approximately one inch and four inches above said hearth at the time prior to said furnace being used for a first melt after lnstallatlcn of said tuyere assembly.
7. An apparatus for stirring a melt of metal in a furnace which includes a tuyere installed in the bottom of said furnace so that it initially extends between one and four inches above the bottom of said furnace and means to connect said tuyere to a supply of gas under pressure for introduction into said melt through said tuyere.
8. An apparatus according to Claim 7 wherein the gas is argon.
9. An apparatus according to Claim 7 wherein the gas is nitrogen.
10. The apparatus of Claim 7 whereon said tuyere assembly includes a tuyere block 20 having a generally trapezoidal cross-sectional shape a tuyere brick 22 set in said block said tuyere brick being connected to a gas supply pipe which extends downwardly through said furnace bottom.
11. The apparatus of Claim 10 so constructed and arranged so that said tuyere brick is readily separated from the furnace bottom by pushing upwardly on said pipe to move said pipe and tuyere brick out of said furnace bottom as a single unit when it is to be replaced.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US76560191A | 1991-09-25 | 1991-09-25 | |
| US07/765601 | 1991-09-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2078640A1 true CA2078640A1 (en) | 1993-03-26 |
Family
ID=25073978
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002078640A Abandoned CA2078640A1 (en) | 1991-09-25 | 1992-09-18 | Electric arc furnace bottom stir tuyere assembly |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA2078640A1 (en) |
| GB (1) | GB2259976A (en) |
| MX (1) | MX9205449A (en) |
| TW (1) | TW206260B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5738811A (en) * | 1995-05-16 | 1998-04-14 | Monofrax Inc. | Process for making fused-cast refractory products |
| FR2735564B1 (en) * | 1995-06-19 | 1997-07-25 | Air Liquide | LANCE FOR INJECTING A FLUID INTO AN ENCLOSURE, METHOD FOR INSTALLING THE SAME AND OVEN BRICK COMPRISING SAME |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4661153A (en) * | 1983-07-01 | 1987-04-28 | Southwire Company | Refractory porous plug |
| GB2179724B (en) * | 1985-08-26 | 1990-02-28 | Labate Michael D | Apparatus for introducing gas into molten metal |
| CA1311787C (en) * | 1986-06-24 | 1992-12-22 | Masahisa Tate | Method of bottom blowing operation of a steel making electric furnace |
| GB8703717D0 (en) * | 1987-02-18 | 1987-03-25 | Injectall Ltd | Injecting gas into metal melts |
| DE3809828A1 (en) * | 1988-03-23 | 1989-10-12 | Radex Heraklith | COOLSTONE |
| DE3907383A1 (en) * | 1988-12-22 | 1990-09-20 | Cookson Plibrico Gmbh | INLET DEVICE |
-
1992
- 1992-08-11 TW TW081106329A patent/TW206260B/zh active
- 1992-09-18 CA CA002078640A patent/CA2078640A1/en not_active Abandoned
- 1992-09-24 MX MX9205449A patent/MX9205449A/en unknown
- 1992-09-24 GB GB9220230A patent/GB2259976A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB9220230D0 (en) | 1992-11-04 |
| GB2259976A (en) | 1993-03-31 |
| TW206260B (en) | 1993-05-21 |
| MX9205449A (en) | 1993-03-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 19970918 |