CN1694774A

CN1694774A - Gas purged nozzle

Info

Publication number: CN1694774A
Application number: CNA038248042A
Authority: CN
Inventors: J·里绍
Original assignee: VESUVIRUS CURCIBLE CO
Current assignee: VESUVIRUS CURCIBLE CO; Vesuvius Crucible Co
Priority date: 2002-09-03
Filing date: 2003-09-02
Publication date: 2005-11-09
Also published as: AU2003268298A1; US20060071041A1; BR0313972A; KR20050057141A; MXPA05002446A; CA2497298A1; PL375692A1; RU2005109547A; EP1536902A1; WO2004022267A1

Abstract

A nozzle (1) is described for delivering a flow of liquid metal from a metallurgical vessel. In combination with inert gas, the nozzle can shield the flow of liquid metal from oxygen and, additionally, can be used to purge liquid metal residing in the metallurgical vessel. The nozzle includes a substantially gas-impermeable liner (9) surrounded by a permeable composition (10). The gas-impermeable liner may comprise a resin-bonded material, and the permeable liner is preferably a carbon-bonded or castable refractory. A metal housing (14) may surround the nozzle.

Description

Ventilating filling pipe end

Invention field

The present invention relates to the refractory nozzle in the casting of molten steel, used, specifically refer to use inert gas to reduce at steel/mouth of a river the mouth of a river of harmful accumulation of alumina deposits at the interface.

Background of invention

In the prior art, refractory product is to be used to control motlten metal, for example molten steel flow.This goods comprise filling pipe end, slide plate, stopper and submersed nozzle etc., and they normally are used, and are used for molten steel control stream in steel pouring process.Because aluminium deoxidation killed steel has desired metallurgical performance, in nineteen seventies, such steel grade becomes a kind of modal product of iron and steel process industry.Yet unfortunately, aluminium oxide and other refractory material component can be in the deposition at the interface and the accumulations of refractory product and molten steel.This interface comprises mouth of a river endoporus and upper surface.This deposition finally may cause the obstruction fully at the mouth of a river or can not close molten steel stream fully.

Inert gas has been used to reduce the harmful deposit on refractory surfaces.Composite nozzle generally includes refractory component porous, air guide.Within the mouth of a river or outside air delivery system, for example passage, groove or device can be directed to multihole device with inert gas.The example at this mouth of a river is a U.S. Patent No. 4,360,190,5,100,035,5,137,189 and 5,723,055.In operation, through the inert gas of supercharging, the refractory component of for example process air delivery system of argon gas, and filtration porous.The element of porous can limit the part of mouth of a river bore area, perhaps can be that inert gas can be gone in the endoporus of the mouth of a river like this near bore area.In addition, multihole device can near or be positioned at the upper surface at the mouth of a river.Through the side of via hole or the formed bubble stream of little argon gas of the end face at the mouth of a river can reduce the harmful deposition of aluminium oxide in these zones.

Studies show that oxygen and mouth of a river component and molten steel react and can produce alumina deposits.Prior art is the dividing potential drop that reduces to cause the oxygen of obstruction by the inert gas that is blown into pressurization.In other words, prior art is that inert gas is blown in the mouth of a river, enters into molten steel stream subsequently again, makes oxygen concentration descend, thus the harmful deposit of corresponding minimizing.This solution is not entirely satisfactory, because still there is oxygen in molten steel, its reason is because such as before just having had aerobic in the pollution of the leakage of inertia system, inert gas and the system.Thereby obstruction still can take place.

Need refractory product and make molten steel and oxygen shielding.Its goods still allow oxygen to spread by goods in the prior art, and enter into molten steel.It is acceptable fully that metal shell is not proved to be yet, because oxygen still can infiltrate along the interface between refractory product and the box hat.In addition, " system shell " increased production cost greatly.Ideal situation is that the mouth of a river forms in the barrier that can't permeate around motlten metal, the oxygen in the inert gas can be removed or is purified.

Summary of the invention

The invention describes the refractory product that uses in the casting of molten steel, these goods have reduced and are exposed to steel and flow the especially deposition of aluminium oxide of lip-deep field trash.This surface can comprise the endoporus or the upper surface at the mouth of a river.

In a broad aspect, these goods comprise two parts, and the first comprises the liner of air-locked refractory assemblies basically, and it two is permeable refractory compositions around this liner.The anti-block of airtight composition is diffused in the motlten metal.Gas-permeable composition is used for the diffusion of inert gas, thereby with airtight composition and motlten metal and oxygen shielding.

Airtight composition is preferably resin-bonded composition, comprises refractory aggregate, bond and antioxidant (oxygen getter).Antioxidant comprises the compound that can remove oxygen in the gas that enters motlten metal, and comprises reactive metal.

Gas-permeable composition can comprise refractory material those carbon combinations, oxide-bonded, resin-bonded or cast molding.Importantly, gas-permeable composition allows the diffusion of inert gas, makes inert gas can prevent basically that block enters airtight composition and motlten metal.The porosity of gas-permeable composition can be controlled the diffusion of inert gas easily.In addition by combining with the porosity, air delivery system, for example passage, groove or device also can be so that transmission and the diffusion of inert gas by gas permeable material.

Method of the present invention comprises with gas-permeable composition at least a portion around this airtight composition, makes gas-permeable composition be full of inert gas with the endoporus that is lining in refractory product in the airtight composition basically.

One of them embodiment is that the inert gas of pressurization is with motlten metal and oxygen shielding.Its another embodiment is to be blown into inert gas to motlten metal in metallurgical tank.

Brief description of the drawings

Fig. 1 shows the cross section of refractory nozzle of the present invention.

Fig. 2 shows another concrete application, is to allow to blow to motlten metal in metallurgical tank.

Detailed description of the present invention

The present invention relates to be used to control the especially refractory product that flows of steel of motlten metal.The present invention can comprise any refractory product that is used to guide motlten metal stream, comprises filling pipe end, submersed nozzle and slide plate.For convenience, filling pipe end should refer to any refractory product that is used to guide motlten metal stream.

Fig. 1 shows example of the present invention.Goods 1 comprise mouth of a river body 2, and this mouth of a river body has the inner surface 3 of having determined endoporus 4, the outlet 7 and the outer surface 8 of the water conservancy diversion that links to each other round the upper surface 5 of the inlet 6 of endoporus 4, with inlet 6.The effect of endoporus 4 be with molten steel from enter the mouth 6 be sent to the outlet 7.Inner surface 3 comprises and contains the liner 9 of airtight composition basically.Liner 9 defines at least a portion of endoporus 4, generally is the whole of endoporus 4.The exterior section 10 at the mouth of a river 2 centers on lining 9, and comprises gas-permeable composition.The mouth of a river 2 is suitable for receiving inert gas flow.In casting process, conduit 11 can be with gas transfer to the mouth of a river 2, and in conjunction with in the mouth of a river 2 or around its various passages, groove or install 12, the gas-permeable composition 10 of gas permeation periphery shields the motlten metal in the endoporus 4 effectively and comes with atmosphere.

Airtight composition must be air-locked basically.Skilled in the art will recognize that the several method that uses some chemistry and mechanical approach to produce non-permeate material.For example, the composition of flux, glaze, particle size distribution, articulated system, refractory material and process condition can be separately and are influenced permeability jointly.Flux reduces vitrification point and is convenient to vitrifying.Glaze produces impermeable coating on the surface of refractory body.Particle size distribution in fire-resistant aggregation can influence the porosity of final products largely, and final influence permeability wherein.Process condition, for example sintering temperature and compacting has very dark influence to permeability.Fire-resistant and chemical composition bonding system also can have very big influence to permeability.

Airtight composition can be made by the material of any kind, comprises resin-bonded, the carbon combination, oxide-bonded and moulding by casting refractory material.The refractory material of carbon combination comprises the mixture of fire-resistant aggregation, graphite and the bond of roasting under reducing condition.Roasting means can form especially heating combination under the temperature of aluminium carbide of metal carbides.This temperature generally is higher than 800 ℃, but depends on that the roasting time temperature can be higher.The composition of oxide-bonded is sintering at high temperature, is significantly higher than carbon usually in conjunction with required temperature.The refractory material of resin-bonded is being lower than about 800 ℃ temperature, often is being to be lower than under about 500 ℃ temperature to solidify.Different with the material of front, the moulding by casting refractory material does not generally need compacting, and can be at the temperature and pressure compacted under near environment.The moulding by casting refractory material is included in normally used refractory cement shape product in the industry.

In preferred embodiments, airtight composition comprises resin-bonded material.This material does not need specially treated process or chemical substance, and is similar to the manufacturing of the refractory material that is used for steel and iron industry.The advantage of this material is, resin-bonded compositions is solidified at low temperatures, can form the anti-clogging material, and can contain antioxidant, this antioxidant be unable to bear carbon in conjunction with or the required high-temperature roasting of material of oxide-bonded.

The appropriate resin binding compositions comprises at least a refractory aggregate, curable resinoid bond and reactive metal.Fire-resistant aggregation comprises any refractory material that is fit to the molten steel casting, includes but are not limited to aluminium oxide, magnesia, calcium oxide, zirconia, silica and their compound and mixture.Preferably, those may at high temperature produce volatile oxidn, and for example silica and magnesian compound should be avoided using, because volatile oxidn is an approach of transmission oxygen in motlten metal, and the deposition that enters with aluminium oxide of oxygen is to be mutually related.

Should there be a certain amount of curable resin binder, to be implemented in compacting and to solidify enough green strengths afterwards.Solidify usually and be lower than about 300 ℃ of generations down.A kind of can being heated to is lower than about 800 ℃, preferably handles being lower than under about 500 ℃ temperature.The amount of bond is not what fix, depends on the green strength of for example employed bond type and expectation.The amount of bond is generally just enough at 1～10wt%.In general, bond is organically, and normally used bond is the carbide resin, for example the carbon-containing bonding agents that is obtained by pitch or resin.Bond can comprise the organic bond of other type, for example the compound of phenol, starch or lignin sulfinate.

Airtight bond can also comprise antioxidant.Antioxidant and the oxygen reaction that diffuses into or form at airtight composition, thus make in molten steel, there is not oxygen.Antioxidant commonly used comprises for example boron compound, carbide, nitride, and the reactive metal powders of aluminium, magnesium, silicon and their mixture and alloy for example.The advantage of boron compound is to reduce the porosity and permeability, thereby forms the physical barriers at the oxygen diffusion.The amount of required antioxidant depends on the concrete purposes of refractory product.Think that at present the amount of 0.25wt% is to show that non-oxidizability has the required minimum of a value of obvious improvement.On the other hand, the cost that the amount of antioxidant is higher than 15wt% is very high, generally is unnecessary, even may be dangerous when using reactive metal powders for example.In addition, antioxidant can reduce the thermal shock resistance of burnt product, and reduces the corrosion resistance to molten steel.

Preferred anti-oxidants comprises reactive metal, comprises aluminium, magnesium, silicon, titanium and their mixture and alloy.Reactive metal adds easily with forms such as powder, sheets, reactive metal should have enough amounts, and reactive metal just can be removed those and may be diffused in the refractory product or any oxygen from wherein coming out during the casting of molten steel like this.Multiple factor affecting is arranged to the amount that is used for except that the reactive metal of deoxidation.For example, the field trash that contains the compound that can discharge oxygen is silica for example, just requires higher levels of reactive metal to remove the oxygen that is discharged.To consider cost and danger to the reactive metal quantitative limitation.Reactive metal generally than fire-resistant aggregation price height, particularly for the reacting metal powder, may be blasted in processing procedure in addition.The addition of reactive metal is 0.5～10wt% in general.

Airtight bond can comprise the resin-bonded bond, and the bond of this resin-bonded comprises the bond of the refractory aggregate of 50～90wt%, 1～10wt% and the reactive metal of 0.5～15wt%.Better choice is, the bond of resin-bonded comprises the metallic aluminium of bond, the 0.5～10wt% of sintered alumina, the 1～10wt% of the aloxite (AI of 65～80wt%, 2～30wt%, the zirconia of the highest 15wt% and the silica that is less than 3wt%.

The permeable refractory composition can comprise any suitable fire proofing composition, comprises the refractory material carbon combination, oxide-bonded, resin-bonded or moulding by casting, but preferably includes the refractory material of carbon combination or the material of moulding by casting.The refractory material of suitable carbon combination has anti-thermal shock stability, is the material of widely approving in this area.The material of moulding by casting mixes dry powder the formation mortar usually with water.Its advantage is, mortar can be in moulding around the ventilative bond, and does not have pressure or temperature extremes.

Gas-permeable composition should center at least a portion of airtight composition, and preferably around whole gas-permeable composition.Compare with airtight composition, the desired feature that has of gas-permeable composition comprises grindability and lower thermal conductivity, but also is not necessary.Grindability allows the easier final size that is worked into of refractory product.Low thermal conductivity makes itself and molten steel thermal insulation, and has reduced the possibility that molten steel solidifies in the mouth of a river.

Gas-permeable composition allows the diffusion of inert gas, and inert gas just can be fully shields the oxygen of motlten metal and airtight composition and intrusion like this.The porosity of gas-permeable composition can be controlled the diffusion of inert gas easily.As explained above, skilled in the art will recognize that a large amount of technology that are used to improve the porosity.Also can use fugitive additive, for example wax and volatile compound improve the porosity.Combine with the porosity and also can adopt air delivery system, for example passage, groove or device are so that inert gas is by the transmission and the diffusion of gas permeable material.

The porosity of refractory material has determined its gas permeability largely.The total porosity of gas-permeable composition should be at least about 15%.Perhaps, the porosity of gas-permeable composition should have than airtight composition about at least 5%.The difference of this porosity is enough to gas is transmitted by gas-permeable composition and away from airtight composition.

Contiguous open pores is especially effective for increasing permeability.Gas can not hinder from a pore to another pore.Big pore size also helps the gas transmission.Compare, little pore size needs bigger pressure to make gas enter gas-permeable composition.Certainly, big pore can reduce the intensity of material.Optimal selection is, the average pore size of breathable refractory materials is at least about 1 micron, and less than 5 millimeters.

Air delivery system can increase the gas transmission.This system is included in the refractory product or lip-deep passage, groove or device.Fig. 1 shows the device 12 in the goods.This device can be bored a hole, to allow the uniform gas distribution along its length.Passage 13 in the mouth of a river 2 has similar function.Usually the wax by will compressing into or cast refractory product in advance or other low melting material are burnt and are formed passage.

Metal-back 14 can use with refractory product, especially when goods are the following mouth of a river of ladle or pans.Metal-back 14 has improved goods globality structurally usually, and forms the mechanical barrier to the oxygen diffusion.A benefit in addition is to can be formed on the outer surface 8 at the mouth of a river 2 and the gas passage of the groove 15 between the metal-back 14.This groove is usually than the easier manufacturing of the gas passage in the refractory product.

Fig. 2 shows another one example of the present invention.Submersed nozzle 2 extends to crystallizer 22 from the inside 21 of pans 20.The mouth of a river 2 comprises the airtight liner 9 that gas-permeable composition 10 centers on.The mouth of a river 2 comprises around the end face 5 of inlet 6.Different with Fig. 1, gas-permeable composition 10 extends to top surface 5.Under pressure than molten steel static pressure head height, force inert gas to pass through gas-permeable composition 10, can force gas to be overflowed from end face 5, thus the motlten metal in the purge pans 20.Significantly, purification for argon can also realize by the suitable mouth of a river with suitable constructions.

Airtight composition and gas-permeable composition should form single refractory product.These parts can be common compactings; A kind of composition can be around another composition or in another composition inside; Comprise that perhaps first and second compositions can be joined together by for example mortar.When being powdery, can adopt first and second compositions method of common compacting, and when these compositions need similarly to handle, for example when two compositions all was the component of resin-bonded, its hardening time was similar, especially can adopt the method for common compacting.

Compacting comprises that the single shaft that waits static pressure and standard suppresses.When being compressed on a kind of composition jointly and suppressing with the prefabricated component of another kind of composition also is possible.For example, a kind of material can be pressed and fired, and forms prefabricated component ventilative, the carbon combination.The material of second kind of airtight composition of formation can be suppressed with permeable preform and is solidified then to form refractory product.

Perhaps, airtight composition can be suppressed, and gas permeable material can be in second kind of material moulding or around it moulding by casting.In such embodiment, slide plate can have the lining that contains gas impermeable material, and the remainder of plate can be the mould material of porous.First and second combination of compositions another method is together comprised first goods that will contain airtight composition are attached on second goods that contains gas-permeable composition.Generally be to use fire mortar in conjunction with these two goods.

Method of the present invention comprises the endoporus that airtight composition basically is lining in refractory product, with gas-permeable composition at least a portion around airtight composition, makes gas-permeable composition be full of inert gas.

In one embodiment, as shown in Figure 1, the inert gas of overvoltage is with motlten metal and oxygen shielding.In another embodiment, as shown in Figure 2, inert gas shields motlten metal and oxygen in the endoporus of the mouth of a river, and purifies the motlten metal in the metallurgical tank.

Significantly, numerous modifications and variations of the present invention all is possible.Therefore, be construed as, the present invention can implement in the scope of claim below, except as otherwise noted.Though the present invention is described for some preferred embodiment, for a person skilled in the art, all will be clearly to different changes of the present invention, improvement and interpolation.All these improve, change and add and all think and be included in the scope of this patent, and are only limited by appended claim.

Claims

(according to the modification of the 19th of treaty)

1. the refractory nozzle that is used for molten metal casting, it has inlet, the outlet that is connected with inlet fluid, outer surface, limits the inner surface of endoporus and the end face that centers on inlet between entrance and exit, this mouth of a river is suitable for receiving inert gas flow, it is characterized in that:

A) be lining in basically all airtight fire proofing compositions of inner surface;

B) around the permeable refractory composition of at least a portion of airtight composition, this gas-permeable composition has the porosity that is enough to allow the inert gas diffusion.

2. according to the refractory nozzle of claim 1, its feature is that also gas-permeable composition has at least 15% the porosity.

3. according to any one refractory nozzle in the aforementioned claim, its feature also is, gas-permeable composition comprises the average pore size of open pores structure and at least 1 micron.

4. according to any one refractory nozzle in the aforementioned claim, its feature also is, the permeable refractory composition be selected from refractory material, the resin-bonded of refractory material, the oxide-bonded of carbon combination refractory material, can cast refractory material and their mixture.

5. according to any one refractory nozzle in the aforementioned claim, its feature is that also airtight fire proofing composition is selected from the refractory material of carbon combination, the refractory material of oxide-bonded, refractory material, moulding by casting refractory material and their mixture of resin-bonded.

6. according to any one refractory nozzle in the aforementioned claim, its feature is that also it contains the airtight composition of antioxidant.

7. according to any one refractory nozzle in the aforementioned claim, its feature also is, airtight composition comprises the refractory material of resin-bonded, and the refractory material of this resin-bonded contains the fire-resistant aggregation of 50～90wt%, the bond of 1～10wt% and the reactive metal of 0.5～15wt%.

8. according to the refractory product of claim 7, its feature is that also fire-resistant aggregation comprises at least a refractory material that is selected from aluminium oxide, zirconia, calcium oxide, magnesia, silica and their mixture and compound.

9. according to any one refractory nozzle in claim 7 and 8, it is characterized in that reactive metal comprises and is selected from aluminium, magnesium, silicon, titanium, at least a metal in their mixture and the alloy.

10. according to any one refractory product in the aforementioned claim, its feature also is, airtight fire proofing composition is made by following mixture, and this mixture comprises the aloxite (AI of 65～80wt%, the sintered alumina of 2～30wt%, the bond of 1～10wt%, the metallic aluminium of 0.5～10wt%, the silica that is up to the zirconia of 15wt% and is less than 3wt%.

11. according to any one refractory nozzle in the aforementioned claim, its feature is that also the mouth of a river comprises the inert gas transfer system.

12. the refractory nozzle according to claim 11 is characterized in that, air delivery system is selected from passage, groove and device.

13. according to any one refractory nozzle in the aforementioned claim, its feature is that also metal shell surrounds the outer surface at the mouth of a river at least in part.

14. according to any one refractory nozzle in the aforementioned claim, its feature is that also gas-permeable composition extends to end face, thereby inert gas can purify motlten metal when the pressure of inert gas surpasses molten steel hydrostatic head in the motlten metal.

Claims

A) be lining in air-locked basically fire proofing composition of inner surface at least a portion;

12. according to any one refractory nozzle in the aforementioned claim, its feature is that also metal shell surrounds the outer surface at the mouth of a river at least in part.

13. according to any one refractory nozzle in the aforementioned claim, its feature is that also gas-permeable composition extends to end face, thereby inert gas can purify motlten metal when the pressure of inert gas surpasses molten steel hydrostatic head in the motlten metal.