CA1141160A - Porous nozzle for molten metal vessel - Google Patents
Porous nozzle for molten metal vesselInfo
- Publication number
- CA1141160A CA1141160A CA000372875A CA372875A CA1141160A CA 1141160 A CA1141160 A CA 1141160A CA 000372875 A CA000372875 A CA 000372875A CA 372875 A CA372875 A CA 372875A CA 1141160 A CA1141160 A CA 1141160A
- Authority
- CA
- Canada
- Prior art keywords
- nozzle
- porous
- gas
- porous nozzle
- flange portion
- 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
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- Treatment Of Steel In Its Molten State (AREA)
- Continuous Casting (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
POROUS NOZZLE FOR MOLTEN METAL VESSEL
A refractory porous nozzle which is arranged at the bottom of a molten metal vessel, characterized in that said porous nozzle is made in one body having a flange portion at its upper portion and a cylindrical portion at its lower portion, the outer peripheral surface of the main body of said porous nozzle is gas-tightly enclosed with a steel shell, a gas pool is provided between the bottom surface of said flange portion and the outer peripheral surface of said cylindrical portion, and the inner peripheral surface of said steel shell, and the gas pool is communicated with an inert gas feeding pipe.
POROUS NOZZLE FOR MOLTEN METAL VESSEL
A refractory porous nozzle which is arranged at the bottom of a molten metal vessel, characterized in that said porous nozzle is made in one body having a flange portion at its upper portion and a cylindrical portion at its lower portion, the outer peripheral surface of the main body of said porous nozzle is gas-tightly enclosed with a steel shell, a gas pool is provided between the bottom surface of said flange portion and the outer peripheral surface of said cylindrical portion, and the inner peripheral surface of said steel shell, and the gas pool is communicated with an inert gas feeding pipe.
Description
POROUS NOZZ~ FOR ~
This invention relates to an improvement in a porous nozzle which is arranged at the bottom of a molten metal vessel, and the objects of which are to float up and separate the non-metallic inclusions in molten metal in said ves~el and to preven-t a slag involvement and a nozzle opening closl~e. More particularly it relate~ to an improvement of a porous nozzle mounted. at the bo-ttom of a ladle or tunidish container of the molten metal vessel.
Generally the nozzle of a ladle or tundish container is constructed with a dense refractory. However, non-metal.lic inclusions in the molten steel often adhere in the nozzle opening during the flowing-down of the melt to cause a contraction and a closure thereby often bring about troubles in the pouring operation of the meltO To prevent these disadvantageous phenomena, therefore, it is generally carried out to employ a refractory porous nozzle in which inert gases are jetted into the inner peripheral surface of the nozzle through the pores thereby to form a gas film and remove the things adhered to the nozzle openingO
~urther, for another porpose, in order that the non-metallic inclusions in the molten steel within the vessel are removed to make a purified and good quality molten steel there is also carried out a method in which separatel~ from a porous nozz:Le, a refractory porous plug is arranged at the ~ ~ .
6~
bottom of a container such as ladle or tundish, and inert gases are jetted into the molten steel through the pores of` the porous plug when the non-metallic inclusions are floated up and separated and the purity of said molten steel is improved. ~here is another method which does not use a porous plug. ~o take a tundish for example, a re-fractory weir is provided within said vessel to change the flow of the molten steel, and the non-metallic inclusions in the molten steel are floated up and separated. Accord-ing to the method in which a weir is provided in a tundish container, it exhibits e-ffects in its own way for floating up and separating the non-metallic inclusions. In view that the dimension of t~mdish is limited because of structure and design of a continuous casting equipment, however, it is difficult to make an effective weir shape or arran~e an effective weir within a comparatively narrow tundish, and it is known that not only the tundish design becomes complicate but also it is difficult to fix a weir within the tundish~
Further, the porous nozzle arran!~ed in conventional tundishes has e~fects for preventing contraction and closure of nozzle, but generally in a continuous casting working said nozzle may involve the non-metallic inclusions, slag, etc. which float up by a -turbulence generated at the upper portion o~ the nozzle opening when the ladle is-replaced, thereby causing a lowered quality of steelO
-~41~61) Furthermore, a~cording to the method in which a porous plug i.s provide~ at the bottom of a tundish cont~iner and inert g~se5 c~re jetted into the molten steel1 i1; is ef~ective Por floating up and separating the inclusions 9 but the plug must be arranged at a position different from that of the nozzle so that a complete effect cannot be exhibited for preventing the slag invol~ement, due to the tubulence generated at the upper portion of the nozz]e opening when replacing the ladle as referred to above.
In view of sai.d various demerits of conventional methods, the present ]nvention provides an integral, f].ange-shaped, porous nozzle ~1hich has in combi.nation a function of jetting inert gases up.wardly into the molten steel by a porous plug and a function of jetting the inert gases from the inner peripheral surface of a porous nozz]e to prevent the nozzle from closing, and in which the in-clusions in the molten steel are floated up and separated whereb~ the nozzle is prevented from closure, and it can avoid a slag involvement caused by the turbulence generated at the upper portion of the nozzle opening when the ladle is replaced, while alIowing a continuous casting of a molten steel of bigh quality. That is, it is the charac-teristic feature of the invention that the porous nozzle of the invention has in combination both the functions of jetting inert gases from the porous refraotory layer of the flange portion into the upper portion in the ' ' - ' .
.' ' ~ ' ' molten steel, and of' ~jet-ting -the inert gases into the nozzle o~ening.
The invention ~i~l now be described ~ore in detail with reference to the accompanying dra~ings which show some embodiments of the invention, in which Fig. 1 shows an embodiment of a porous nozzle of the invention and a vertical section of a porous nozzle in one body in which the bottom of the flange portion is communicated with à gas pool of the cylindrical outer circumference;
Fig. 2 shows another embodiment of the invention and a vertical section of a porous nozzle in which the flange portion and the cylindrical portion are made in one body through a sealing member;
Fig. 3 shows still another embodiment of the invention and a vertical section of a porous nozzle in which the flange portion and the cylindrical portion are made in one body throllgh a fine porous refractory layer;
and Fig. 4 is a vertical sectional view showing a state in which the porous nozæle of Fig. 2 is set at the bottom of a molten metal vessel.
In Fig. 1 the porous nozzle arranged at the pouring-out portion a-t the bottom of a molten steel vessel is mounted in the nozzle socket at the central portion of a nozzle-receiving brick, the outer peripheral surface of 16t~
which brick being .in contac-t W:i th -the :Li.n:i.n~ refrcactory brick o:~ said vessel bottom. 'I'he ob,jec-t o-L'-the ~n-vention is to provide an exce~lent pvrc)us nozY,:Ie in T~hich -the vessel. ls surrouned with an lron she:L] (3~ ln such a manner that a circular gas pool (2) ls provided at least at a part or -the whole of t;he ou-ter periphera] sur~'ace of a porous refractory layer constitu-ting the main body of a porous no~æle (1) and at least at a pa:rt or the whole o-f the flange portion at the lo~er end Or a f1.ange porous ~ayer (la), the gas pool (2) is communicated with a vent cleara.nce (2a) in the outer periphera] surface of the noz~,le cylindrical portion9 inert gases are jetted through a piping ~rom the outside into a nozzl.e opening (lla) ~rom the upper surface of said porous refrac-tory layer (la) constitutin~ the ~lange portion of the porous nozzle and from the inner periphery surface of a porous refractory layer (lb) constituti.ng the nozzle cylindrical portion, and by doing so it is possible easily to float up and separate the non-metallic inclusions in the molten steel while preventing th.e nozzle openin~ from cl.osure and slag involvement, Fig. 2 shows an embodiment of a pOI'OUS nozzle where the porous refractory layer of Fig. 1 is ma.de double.
~hat is, this porous nozæle is the one in w}hich the porous refractory layer (la) is isolated by a sealin~ member'(5) from the porous refractory layer (lb) constituting the .
cylindrical portion whereby -the f-llnctio:n o.t jet-ti.n~ the inert gases upwardly in -the mol-ten s-teeL is separa-ted from the funct.ion of jetting them i.nto an nozæle openlng (].la).
The present porous noz%]e has in one u.nlt a mechanism of jetting ~ases to the upper su.r-face of the ~lange, per-meating the pores of t;he f].ange porous refractory layer through a gas bl.owing opening (4) rnounted at the end of a gas pool (2) prov].aed i.n the c.ircumference at -th.e lower end o. the f1ange of said porous nozz].e, and a mechanism of jetting t;he gases in-to the nozzle opening (lla), permea.ting the pores of the porous refractory layer (lb) o.E the nozzle cylindrical portion through a gas pool (2a) surrounded by an iron shell (3). A sealin~ member (5) of separeting said two mechanism may be made of silica, alumina or any other optional sintered refractory -to prevent gas leakage completely, and the importan-t thing is that a gas leakage to the outside is prevented and that a gas per-meation is prevented between the refractory porous layer of the flange portion and the porous refractory layer of the nozzle cylindrical portion through said sealing member (5).
The reason of separating the gas ejection mechanism in the flange upper sur~ace from that in the noPzle opening (lla) is that specifically in a porous nozæle for tundish container, owing to the physical pressure difference between the molten steel sta-tic pressure within the tundish, which .
is received by the upper sur.~ace o'' the ~]"ange, and the molten steel kine-tic pressure (pressure is reduced ~ased on the ~ernoulli's theorem) ~rh:i.ch is recei.ved by the inner peripheral surf~ce O r the :nozz:l.e dur:i.ng the time when the molten steel flows down within said nozzle opening, it is necessary to separa.tely adjlls-t -the gas bl.owing pressure in the fl.ange portion and that in1;o the noz%le opening (lla).
Concerning the pressure of the ga,s blown into the nozzle opening (lla), it is possible to prevent the nozzle from contrac-tion and closure by forming a gas curtai.n in the inner peripheral surface o~ the nozzl,e opening, and with a gas pressure unnecessarily raised the inert gases are involved into the molten steel when the melt ~lows down into the nozzle opening, and -there-fore there is an un-favorable possibility that pin holes occur in the solidi,fy-ing process of the molten steel. Further, the present invention has a great number of merits in such that in the case o~ a closing mechanism of a sl.iding nozzle (lo~er nozzle) constituting the lo~er portion of said porous nozzle, it wi~l suf~ice only -to eject gas from the upper surface of the flange thanks to a plurality of blow openin~s as arranged, and if necessary it is capable of adjusting the gas ejection and gas pressure ~reely so as to save the use amount of inert gases.
According to the porous nozzle of Fig. ~, the porous refractory layer of the main body of said porous nozzle is :
.
constructed in such a way tha-t bet-~een the porous refractory layer o-~ the fl~.nge portlon a:nd that of the cylindrical.
p~rtion there i.s formecl a fine porous :reEractory layer (6) which is fine porosity an~ has a great gas resistancy compared with th.e porous refractory layer of the rnain porous body, inert ga.ses are guided L:rom the ga~ blow opening (4) and the gases are ~etted, -through the gas pool (2), -from the upper surface of the flange, permeating the pores of the porous refractory layer (la) o-f the,flange portion, while a part of -the inert gases permeates through the porous refractory layer (lb) of the vertical side through the fine porous refractory layer (6) thereby to be jetted into the nozzle opening. When a part of the inert gases permeates through said :fine porous refractory layer (6) . 15 the gas pressure is considerably reduced so that the amount ; of the gas entering into the nozzle opening (lla) is de-;: creased and there-fore9 the molten steel will never be involved with inert gas.
: In the drawings the fine porous refractory layer is : 20 not flat in its sectional configuration.but i-t may be o-f optional shape, and naturally the thickness o-f said layer is optionally selected and said layer is formed in shape and thickness answering the conditlons, considering the permeation and resistance of the gas.
~: 25 Fig. 4 is a schematical sectional view of the porous nozzle of Flg, 2, in which the porous nozzle wherein the a~
.
, ' ' ' . ~ :
' ~ ":
.,:
o _ 9 _ e~ection mech~nism ~rom the f]ange surface is separated from that into the nozzle opening, ix arranged at the bottom O:e a mo~ten me-tal vessel. Further, Fig. 4 is also a sectional view o~ the porous nozzle (1) as arranged, in T~rhlch a through hole is provided at the bottom of a vessel where a iron casing (7) is lined wi-th re-fractory bricks (8), said porous nozzle being mounted in the central zone of the inner peripheral sur~ace of a nozzle-receiving brick (9) flxed in said through hole. Fig, 4 is exampli~ied with a porous nozzle being connected at its lower end to a sliding nozzle (10), but said nozzle can naturally be applicable to melt discharging nozzles which adopt a stopper system as a nozzle opening and closing mechanism.
lhe invention will now be described by way o~ example.
By mounting the porous nozzle (shown in Fig. 2) of the invention to a tundish container there was carried out a 4-continuous casting operation for steel plates for motor-cars, but as e~pected initially there was neither contraction nor closure of the nozzle at all, and not observed any slag involvement when the ladle was replaced. Moreover, even the index of the non-metallic inclusions could be reduced by 30~40~o compared with conventional porous nozzles to obtain a very satisfactory result. ~he conditions of carrying out the operation are as follows:
' ' , .~,a3L~ 60 Kind of ~teel: S-teel plate for motorcar Ca~aclty of tundjsh: 45 t Number of continuous 4-continuous casting (cc) Capacity of ladle: 280 t Casting tonnage: 280 x 4 = 1,120 t Blow amount of lnert gas (Ar):
A) Gas pool blow opening (4) of the -flange portion Gas pressure: 0.9 kg/cm2 Gas flow: 8 N~/min B) Blow opening (4a) of the cylindrical portion Gas pressure: 0 7 kg/cm2 as flow: 6 N~/min The more the porous nozzle of the invention widens its width in an operable range in the length in the width direction of the flange, the more it produces its effect.
However, putting the shape and capacity of the melt vessel and the problems of said vessel when operating into con-sideratlon the optimum width and thickness of the flange should be selected. In the draw~ngs the upper surface of the ilange is shown in a flat con-figuration, but the shape is not limited to said configuration and there is no trouble in use even if the surface is curved or uneven a little. The important thing is that the porous nozzle has a function for ejecting an inert gas toward the upper portion of the molten metal. The porous nozzle of the .
invention has been described in detail particularly with respect to a tundish nozzle for molten steel, but the present inven-tion is very useful industrially in that it is applicable to vessels for other molten metals such as copper.
::
,
This invention relates to an improvement in a porous nozzle which is arranged at the bottom of a molten metal vessel, and the objects of which are to float up and separate the non-metallic inclusions in molten metal in said ves~el and to preven-t a slag involvement and a nozzle opening closl~e. More particularly it relate~ to an improvement of a porous nozzle mounted. at the bo-ttom of a ladle or tunidish container of the molten metal vessel.
Generally the nozzle of a ladle or tundish container is constructed with a dense refractory. However, non-metal.lic inclusions in the molten steel often adhere in the nozzle opening during the flowing-down of the melt to cause a contraction and a closure thereby often bring about troubles in the pouring operation of the meltO To prevent these disadvantageous phenomena, therefore, it is generally carried out to employ a refractory porous nozzle in which inert gases are jetted into the inner peripheral surface of the nozzle through the pores thereby to form a gas film and remove the things adhered to the nozzle openingO
~urther, for another porpose, in order that the non-metallic inclusions in the molten steel within the vessel are removed to make a purified and good quality molten steel there is also carried out a method in which separatel~ from a porous nozz:Le, a refractory porous plug is arranged at the ~ ~ .
6~
bottom of a container such as ladle or tundish, and inert gases are jetted into the molten steel through the pores of` the porous plug when the non-metallic inclusions are floated up and separated and the purity of said molten steel is improved. ~here is another method which does not use a porous plug. ~o take a tundish for example, a re-fractory weir is provided within said vessel to change the flow of the molten steel, and the non-metallic inclusions in the molten steel are floated up and separated. Accord-ing to the method in which a weir is provided in a tundish container, it exhibits e-ffects in its own way for floating up and separating the non-metallic inclusions. In view that the dimension of t~mdish is limited because of structure and design of a continuous casting equipment, however, it is difficult to make an effective weir shape or arran~e an effective weir within a comparatively narrow tundish, and it is known that not only the tundish design becomes complicate but also it is difficult to fix a weir within the tundish~
Further, the porous nozzle arran!~ed in conventional tundishes has e~fects for preventing contraction and closure of nozzle, but generally in a continuous casting working said nozzle may involve the non-metallic inclusions, slag, etc. which float up by a -turbulence generated at the upper portion o~ the nozzle opening when the ladle is-replaced, thereby causing a lowered quality of steelO
-~41~61) Furthermore, a~cording to the method in which a porous plug i.s provide~ at the bottom of a tundish cont~iner and inert g~se5 c~re jetted into the molten steel1 i1; is ef~ective Por floating up and separating the inclusions 9 but the plug must be arranged at a position different from that of the nozzle so that a complete effect cannot be exhibited for preventing the slag invol~ement, due to the tubulence generated at the upper portion of the nozz]e opening when replacing the ladle as referred to above.
In view of sai.d various demerits of conventional methods, the present ]nvention provides an integral, f].ange-shaped, porous nozzle ~1hich has in combi.nation a function of jetting inert gases up.wardly into the molten steel by a porous plug and a function of jetting the inert gases from the inner peripheral surface of a porous nozz]e to prevent the nozzle from closing, and in which the in-clusions in the molten steel are floated up and separated whereb~ the nozzle is prevented from closure, and it can avoid a slag involvement caused by the turbulence generated at the upper portion of the nozzle opening when the ladle is replaced, while alIowing a continuous casting of a molten steel of bigh quality. That is, it is the charac-teristic feature of the invention that the porous nozzle of the invention has in combination both the functions of jetting inert gases from the porous refraotory layer of the flange portion into the upper portion in the ' ' - ' .
.' ' ~ ' ' molten steel, and of' ~jet-ting -the inert gases into the nozzle o~ening.
The invention ~i~l now be described ~ore in detail with reference to the accompanying dra~ings which show some embodiments of the invention, in which Fig. 1 shows an embodiment of a porous nozzle of the invention and a vertical section of a porous nozzle in one body in which the bottom of the flange portion is communicated with à gas pool of the cylindrical outer circumference;
Fig. 2 shows another embodiment of the invention and a vertical section of a porous nozzle in which the flange portion and the cylindrical portion are made in one body through a sealing member;
Fig. 3 shows still another embodiment of the invention and a vertical section of a porous nozzle in which the flange portion and the cylindrical portion are made in one body throllgh a fine porous refractory layer;
and Fig. 4 is a vertical sectional view showing a state in which the porous nozæle of Fig. 2 is set at the bottom of a molten metal vessel.
In Fig. 1 the porous nozzle arranged at the pouring-out portion a-t the bottom of a molten steel vessel is mounted in the nozzle socket at the central portion of a nozzle-receiving brick, the outer peripheral surface of 16t~
which brick being .in contac-t W:i th -the :Li.n:i.n~ refrcactory brick o:~ said vessel bottom. 'I'he ob,jec-t o-L'-the ~n-vention is to provide an exce~lent pvrc)us nozY,:Ie in T~hich -the vessel. ls surrouned with an lron she:L] (3~ ln such a manner that a circular gas pool (2) ls provided at least at a part or -the whole of t;he ou-ter periphera] sur~'ace of a porous refractory layer constitu-ting the main body of a porous no~æle (1) and at least at a pa:rt or the whole o-f the flange portion at the lo~er end Or a f1.ange porous ~ayer (la), the gas pool (2) is communicated with a vent cleara.nce (2a) in the outer periphera] surface of the noz~,le cylindrical portion9 inert gases are jetted through a piping ~rom the outside into a nozzl.e opening (lla) ~rom the upper surface of said porous refrac-tory layer (la) constitutin~ the ~lange portion of the porous nozzle and from the inner periphery surface of a porous refractory layer (lb) constituti.ng the nozzle cylindrical portion, and by doing so it is possible easily to float up and separate the non-metallic inclusions in the molten steel while preventing th.e nozzle openin~ from cl.osure and slag involvement, Fig. 2 shows an embodiment of a pOI'OUS nozzle where the porous refractory layer of Fig. 1 is ma.de double.
~hat is, this porous nozæle is the one in w}hich the porous refractory layer (la) is isolated by a sealin~ member'(5) from the porous refractory layer (lb) constituting the .
cylindrical portion whereby -the f-llnctio:n o.t jet-ti.n~ the inert gases upwardly in -the mol-ten s-teeL is separa-ted from the funct.ion of jetting them i.nto an nozæle openlng (].la).
The present porous noz%]e has in one u.nlt a mechanism of jetting ~ases to the upper su.r-face of the ~lange, per-meating the pores of t;he f].ange porous refractory layer through a gas bl.owing opening (4) rnounted at the end of a gas pool (2) prov].aed i.n the c.ircumference at -th.e lower end o. the f1ange of said porous nozz].e, and a mechanism of jetting t;he gases in-to the nozzle opening (lla), permea.ting the pores of the porous refractory layer (lb) o.E the nozzle cylindrical portion through a gas pool (2a) surrounded by an iron shell (3). A sealin~ member (5) of separeting said two mechanism may be made of silica, alumina or any other optional sintered refractory -to prevent gas leakage completely, and the importan-t thing is that a gas leakage to the outside is prevented and that a gas per-meation is prevented between the refractory porous layer of the flange portion and the porous refractory layer of the nozzle cylindrical portion through said sealing member (5).
The reason of separating the gas ejection mechanism in the flange upper sur~ace from that in the noPzle opening (lla) is that specifically in a porous nozæle for tundish container, owing to the physical pressure difference between the molten steel sta-tic pressure within the tundish, which .
is received by the upper sur.~ace o'' the ~]"ange, and the molten steel kine-tic pressure (pressure is reduced ~ased on the ~ernoulli's theorem) ~rh:i.ch is recei.ved by the inner peripheral surf~ce O r the :nozz:l.e dur:i.ng the time when the molten steel flows down within said nozzle opening, it is necessary to separa.tely adjlls-t -the gas bl.owing pressure in the fl.ange portion and that in1;o the noz%le opening (lla).
Concerning the pressure of the ga,s blown into the nozzle opening (lla), it is possible to prevent the nozzle from contrac-tion and closure by forming a gas curtai.n in the inner peripheral surface o~ the nozzl,e opening, and with a gas pressure unnecessarily raised the inert gases are involved into the molten steel when the melt ~lows down into the nozzle opening, and -there-fore there is an un-favorable possibility that pin holes occur in the solidi,fy-ing process of the molten steel. Further, the present invention has a great number of merits in such that in the case o~ a closing mechanism of a sl.iding nozzle (lo~er nozzle) constituting the lo~er portion of said porous nozzle, it wi~l suf~ice only -to eject gas from the upper surface of the flange thanks to a plurality of blow openin~s as arranged, and if necessary it is capable of adjusting the gas ejection and gas pressure ~reely so as to save the use amount of inert gases.
According to the porous nozzle of Fig. ~, the porous refractory layer of the main body of said porous nozzle is :
.
constructed in such a way tha-t bet-~een the porous refractory layer o-~ the fl~.nge portlon a:nd that of the cylindrical.
p~rtion there i.s formecl a fine porous :reEractory layer (6) which is fine porosity an~ has a great gas resistancy compared with th.e porous refractory layer of the rnain porous body, inert ga.ses are guided L:rom the ga~ blow opening (4) and the gases are ~etted, -through the gas pool (2), -from the upper surface of the flange, permeating the pores of the porous refractory layer (la) o-f the,flange portion, while a part of -the inert gases permeates through the porous refractory layer (lb) of the vertical side through the fine porous refractory layer (6) thereby to be jetted into the nozzle opening. When a part of the inert gases permeates through said :fine porous refractory layer (6) . 15 the gas pressure is considerably reduced so that the amount ; of the gas entering into the nozzle opening (lla) is de-;: creased and there-fore9 the molten steel will never be involved with inert gas.
: In the drawings the fine porous refractory layer is : 20 not flat in its sectional configuration.but i-t may be o-f optional shape, and naturally the thickness o-f said layer is optionally selected and said layer is formed in shape and thickness answering the conditlons, considering the permeation and resistance of the gas.
~: 25 Fig. 4 is a schematical sectional view of the porous nozzle of Flg, 2, in which the porous nozzle wherein the a~
.
, ' ' ' . ~ :
' ~ ":
.,:
o _ 9 _ e~ection mech~nism ~rom the f]ange surface is separated from that into the nozzle opening, ix arranged at the bottom O:e a mo~ten me-tal vessel. Further, Fig. 4 is also a sectional view o~ the porous nozzle (1) as arranged, in T~rhlch a through hole is provided at the bottom of a vessel where a iron casing (7) is lined wi-th re-fractory bricks (8), said porous nozzle being mounted in the central zone of the inner peripheral sur~ace of a nozzle-receiving brick (9) flxed in said through hole. Fig, 4 is exampli~ied with a porous nozzle being connected at its lower end to a sliding nozzle (10), but said nozzle can naturally be applicable to melt discharging nozzles which adopt a stopper system as a nozzle opening and closing mechanism.
lhe invention will now be described by way o~ example.
By mounting the porous nozzle (shown in Fig. 2) of the invention to a tundish container there was carried out a 4-continuous casting operation for steel plates for motor-cars, but as e~pected initially there was neither contraction nor closure of the nozzle at all, and not observed any slag involvement when the ladle was replaced. Moreover, even the index of the non-metallic inclusions could be reduced by 30~40~o compared with conventional porous nozzles to obtain a very satisfactory result. ~he conditions of carrying out the operation are as follows:
' ' , .~,a3L~ 60 Kind of ~teel: S-teel plate for motorcar Ca~aclty of tundjsh: 45 t Number of continuous 4-continuous casting (cc) Capacity of ladle: 280 t Casting tonnage: 280 x 4 = 1,120 t Blow amount of lnert gas (Ar):
A) Gas pool blow opening (4) of the -flange portion Gas pressure: 0.9 kg/cm2 Gas flow: 8 N~/min B) Blow opening (4a) of the cylindrical portion Gas pressure: 0 7 kg/cm2 as flow: 6 N~/min The more the porous nozzle of the invention widens its width in an operable range in the length in the width direction of the flange, the more it produces its effect.
However, putting the shape and capacity of the melt vessel and the problems of said vessel when operating into con-sideratlon the optimum width and thickness of the flange should be selected. In the draw~ngs the upper surface of the ilange is shown in a flat con-figuration, but the shape is not limited to said configuration and there is no trouble in use even if the surface is curved or uneven a little. The important thing is that the porous nozzle has a function for ejecting an inert gas toward the upper portion of the molten metal. The porous nozzle of the .
invention has been described in detail particularly with respect to a tundish nozzle for molten steel, but the present inven-tion is very useful industrially in that it is applicable to vessels for other molten metals such as copper.
::
,
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A refractory porous nozzle which is arranged at the bottom of a molten metal vessel, characterized in that said porous nozzle is made in one body having a flange portion at its upper portion and a cylindrical portion at its lower portion, the outer peripheral surface of the main body of said porous nozzle is gas-tightly enclosed with a steel shell, a gas pool is provided between the bottom surface of said flange portion and the outer peripheral surface of said cylindrical portion, and the inner peripheral surface of said steel shell, and the gas pool is communicated with an inert gas feeding pipe.
2. A porous nozzle as described in Claim 1 wherein the flange portion and cylindrical portion of the nozzle are constructed in one body through a sealing member, and each gas pool is communicted with an inert gas feeding pipe.
3. A porous nozzle as described in Claim 1 wherein the flange portion and cylindrical portion of the nozzle is constructed in one body through a porous refractory layer more fine than in the nozzle body, a gas pool is provided only at the lower surface of said flange portion, and said gas pool is communicated with an inert gas feeding pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000372875A CA1141160A (en) | 1981-03-12 | 1981-03-12 | Porous nozzle for molten metal vessel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000372875A CA1141160A (en) | 1981-03-12 | 1981-03-12 | Porous nozzle for molten metal vessel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1141160A true CA1141160A (en) | 1983-02-15 |
Family
ID=4119436
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000372875A Expired CA1141160A (en) | 1981-03-12 | 1981-03-12 | Porous nozzle for molten metal vessel |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1141160A (en) |
-
1981
- 1981-03-12 CA CA000372875A patent/CA1141160A/en not_active Expired
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| MKEX | Expiry |