CN102712036A - Mould powder for continuous casting of steel - Google Patents
Mould powder for continuous casting of steel Download PDFInfo
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- CN102712036A CN102712036A CN2011800063522A CN201180006352A CN102712036A CN 102712036 A CN102712036 A CN 102712036A CN 2011800063522 A CN2011800063522 A CN 2011800063522A CN 201180006352 A CN201180006352 A CN 201180006352A CN 102712036 A CN102712036 A CN 102712036A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
-
- 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
- C21C7/076—Use of slags or fluxes as treating agents
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- 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
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- Engineering & Computer Science (AREA)
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- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Provided is a mould powder for continuous casting that is used in order to continuously cast steel containing at least one of Al and Ti. The mould powder has a CaO/SiO2 mass ratio of 1.0 to 1.5. The mould powder contains 15 to 30 mass% of SiO2, 30 to 40 mass% of CaO, 3 to 25 mass% of Al2O3, 2 to 6 mass% of Na2O, more than 2 mass% but 10 mass% or less of F added in the form of CaF2 or NaF, and 1 to 4 mass% of B2O3 such that thesum of the mass% of SiO2, Na2O, and B2O3 is 20 to 40 mass% and the remainder is inevitable impurities. The mould powder has a viscosity at 1,300 C of 0.5 to 8 poise.
Description
Technical field
The present invention relates to a kind of when continuously casting steel, be added in the crystallizer (casting mold) the continuous casting mold powder that uses.
Background technology
When the continuous casting molten steel, add moulding powder (following be designated as sometimes " powder ") on the liquid steel level in crystallizer.Characteristic below powder requires.
1) covers liquid steel level through the formed melted powder layer of powder fusion on liquid steel level and not melted powder layer above that,, prevent reoxidizing and carrying out heat preservation effect of molten steel thereby will have with contacting of air by isolated.
2) powder of fusion owing to must flow between crystallizer and the solidified shell plays a role as lubricant, thereby the powder that will have a frequent supply appropriate amount to be adapting to the depletion rate of powder, thereby reaches the fusion speed of the melted powder pond thickness of appropriate amount.
3) the melted powder layer is absorbed in the non-metallic inclusion that floats up in the molten steel, and the variation of its rerum natura (viscosity, melt temperature, setting temperature etc.) is little.
4) powder of fusion flows between crystallizer and the solidified shell, form uniform powder film, thereby powder film will have lubrication between crystallizer and solidified shell.
5) powder of fusion has suitable viscosity, interfacial tension, and the powder of fusion can not be involved in the molten steel.
In the continuous casting operation, local liquid level change and flow the interface of formed MOLTEN STEEL FLOW upset powder and molten steel because of the injection that is injected into the molten steel in the crystallizer, thereby the powder of fusion is involved in the molten steel sometimes.
In addition, when the molten steel that contains Al or Ti is cast continuously, because the powder of fusion contacts with molten steel, thereby the Al in the molten steel or Ti and as the SiO of the main component in the powder
2Between reaction below taking place.
4〔Al〕＋3（SiO
2）→2（Al
2O
3）＋3〔Si〕（1）
〔Ti〕＋（SiO
2）→（TiO
2）＋〔Si〕?（2）
At this, () is the composition in the molten steel, and () is the composition in the melted powder.When between molten steel and melted powder interface, producing the reaction as above-mentioned, the interfacial tension between molten steel and melted powder reduces greatly, thereby the powder in the molten steel is involved in the generation more easily that becomes.
The major part that is involved in the melted powder in the molten steel floats up again, catches and remains on the strand but its part often is solidified shell.The powder that remains in the steel mesexine becomes the cord defects of product surface.In addition, residual powder becomes the occurrence cause of pressure processing crackle in inside.These phenomenons take place when casting fast especially easily.In, low speed when casting, for the strict steel of quality requirements such as tinplate material, automotive sheet, these phenomenons usually become problem.
For this reason, as preventing that powder is involved in the countermeasure in the molten steel, has developed following powder etc.: shown in patent documentation 1, have a powder that high viscosity and high capillary difficulty are involved in; The powder that the difficulty with high interfacial tension shown in the patent documentation 2 is involved in; Passing through shown in the patent documentation 3 suppresses Al and the SiO in Ti and the powder in the molten steel
2Reaction prevent the significantly reduction of the interfacial tension between molten steel and melted powder, thereby suppress powder being involved in molten steel.
On the other hand, hindered and damage under the situation of lubrication to the crystallizer of melted powder and the inflow between solidified shell at the powder of fusion, in crystallizer, it is unstable that the heat extraction between solidified shell and the crystallizer (heat extraction) becomes.Consequently, solidifying of strand becomes inhomogeneous, causes the generation of strand crackle, and then produces bleedout (breakout).Bleedout causes that not only operation stops, the reduction of output, and continuous casting equipment is caused great infringement.Therefore, in order in crystallizer, to improve the uniformity of solidifying of strand, thereby prevent the generation of crackle and bleedout, the interior heat extraction of crystallization control device stably is very important.So people have developed and both satisfied in high viscosity shown in the patent documentation 4 and high basicity, thereby in powder film, separate out the powder that heat extraction is stably controlled in stable crystallization again.
In addition, in containing the Al steel, also there is unsettled problem thereby the heat extraction in generation insufficient lubrication or the crystallizer becomes because in powder, separating out the high-melting-point crystal is cacoclasite.So, as shown in the patent documentation 5, developed the caused molten steel of the reaction that prevents invar water and powder and polluted, pass through Li simultaneously
2The interpolation of O and F and prevent that the high-melting-point crystal from being the powder of separating out of cacoclasite.
Patent documentation 6 has proposed a kind of powder; It is in the viscosity of the powder of molten condition through raising; Make the inflow of powder between crystallizer and solidified shell for a small amount of and even; Weaken the crystallization tendency of powder simultaneously, the state of slag film is become evenly, thus the homogenising of seeking the heat extraction in crystallizer.
Moreover patent documentation 7 has proposed a kind of powder, and it makes powder contain ZrO
2, TiO
2And Cr
2O
3Among more than one oxide, thereby the homogenising of seeking the heat extraction in crystallizer.
The prior art document
Patent documentation
Patent documentation 1: japanese kokai publication hei 2-25254 communique
Patent documentation 2: TOHKEMY 2000-071051 communique
Patent documentation 3: TOHKEMY 2008-264791 communique
Patent documentation 4: TOHKEMY 2005-040835 communique
Patent documentation 5: TOHKEMY 2006-110578 communique
Patent documentation 6: International Publication WO00/33992 brochure
Patent documentation 7: japanese kokai publication hei 8-33962 communique
Summary of the invention
Invent problem to be solved
But; In order to adapt to further the requirement of castingization and quality raising fast; As the powder of record in the patent documentation 1; If just change powder constituent and make it high viscosityization, then can not guarantee the suitable powder influx between crystallizer and the solidified shell, thereby can not keep lubricity in order to prevent to be involved in.In addition, cause the possibility of bleedout to get rid of fully.
In the powder that patent documentation 2 is put down in writing, because CaO/SiO
2Very high, reach more than 7, thereby the setting temperature rising, the influx of suitable powder can not be guaranteed, thereby the lubricity between crystallizer and the solidified shell can not be kept.Therefore, can not get rid of the possibility that causes bleedout fully.In addition, because the SiO in the powder
2Amount is few, Al
2O
3Amount is many, thereby to separate out the high-melting-point crystal be cacoclasite, thereby might hinder lubricatedly, makes the heat extraction in the crystallizer become unstable simultaneously.
In the powder that patent documentation 3 is put down in writing, because viscosity is big, thereby the uniform inflow property of infringement between crystallizer and solidified shell, can not keep sufficient lubricity.Therefore, can not get rid of the possibility that causes bleedout fully.In addition, owing to contain a large amount of Al in order to ensure viscosity
2O
3, thereby to separate out the high-melting-point crystal be cacoclasite, thus might make heat extraction become unstable.
In the powder that patent documentation 4 is put down in writing, be that cacoclasite etc. is separated out energetically owing to make the high-melting-point crystal, thereby might hinder the inflow property and the lubricity of powder, make the heat extraction of high-melting-point crystal in crystallizer become unstable simultaneously.
In the powder that patent documentation 5 is put down in writing, the high-melting-point crystal is that separating out of cacoclasite is suppressed, but the Li that contains in the powder
2Al in O and the molten steel and Ti react and interfacial tension are reduced, thereby exist powder to be involved in the possibility in the molten steel easily.
Like this, in the powder that patent documentation 1～5 is put down in writing, take into account and prevent that the heat extraction that powder is involved in the molten steel and stable crystallization control device is interior from being very difficult.
In addition, in the powder that patent documentation 6 is put down in writing, reduce the F composition and improve viscosity.Therefore, the powder influx of fusion also can be less, and the problem of existence is the casting that can only be applicable to bloom and steel billet.
And the powder of record in the patent documentation 7 contains ZrO
2, TiO
2And Cr
2O
3, hinder the transfer of radiant heat of melted powder in liquid phase, thus scattering or absorption radiation of heat in liquid phase.Therefore, there is the interior heat extraction problem of unstable of crystallizer.
The present invention accomplishes in view of such situation; Its purpose is to provide a kind of continuous casting of steel to use powder; It has suppressed powder being involved in molten steel through suppressing the reaction of molten steel and powder, thereby can not resulted from the high-quality product of defective of powder; And make the heat extraction in the crystallizer stable, thereby can not hinder productivity ratio.
Be used to solve the means of problem
The main points of the present invention that are used to solve above-mentioned problem are following:
(1) a kind of continuous casting mold powder of steel, the continuous casting that it is used for containing at least a steel of Al or Ti is characterized in that: CaO/SiO
2Be 1.0～1.5 by quality ratio, contain SiO
2Be 15 quality %～30 quality %, CaO is 30 quality %～40 quality %, Al
2O
3Be 3 quality %～25 quality %, Na
2O is 2 quality %～6 quality %, with CaF
2Or the F composition that NaF adds is greater than 2 quality % but smaller or equal to 10 quality %, B
2O
3Be 1 quality %～4 quality %, SiO
2, Na
2O and B
2O
3Quality % sum be 20 quality %～40 quality %, remainder comprises unavoidable impurities; Viscosity under 1300 ℃ is 0.5poise～8poise.
Wherein, CaO all is scaled CaO and the value that obtains with the Ca that contains in the powder.
(2) according to the continuous casting mold powder of above-mentioned (1) described steel, it is characterized in that: further contain ZrO
2: among 2 quality %～10 quality %, the SrO:2.5 quality %～10 quality % more than a kind.
The effect of invention
According to the present invention; Can provide a kind of continuous casting of steel to use powder, even it is under situation about casting continuously with the molten steel that contains Al or Ti, through suppressing the reaction of molten steel and powder; Also suppressed powder being involved in molten steel; Thereby can not resulted from the high-quality product of defective of powder, and make the heat extraction in the crystallizer stable, thereby can not hindered productivity ratio.
The specific embodiment
Along with the quickening of casting speed, the powder in the molten steel is involved in increase, thereby produces the such defective that results from powder of cord defects and pressure processing crackle, so preferably use more is difficult to produce the powder that powder is involved in.But, be in the powder of target above-mentioned being involved in difficulty, the problem of existence is owing to separate out the high-melting-point crystal, thereby can not keep the sufficient lubricity between crystallizer and the solidified shell, and is unstable thereby heat extraction becomes.
So, when the molten steel that the inventor is contained Al or Ti in use casts continuously, be involved in order to prevent the powder in the molten steel, can carry out the stable control of the heat extraction in the crystallizer simultaneously, it has been carried out research with great concentration repeatedly.
Consequently, the inventor finds recently: if make the F composition that contains ormal weight in the powder wittingly, then the fusing point of powder descends, and SiO
2Activity reduce.In addition, also new discovery of the inventor: through reducing SiO
2Activity, above-mentioned (1) formula, represented molten steel and the SiO of (2) formula
2Reaction just can not take place, thereby being involved in to become and being difficult to take place of powder.
In addition, also new discovery of the inventor is if contain the B of ormal weight in powder
2O
3, then also can suppress the generation of high-melting-point crystal, the heat extraction instability of high-melting-point crystal can not occur resulting from, thereby make the heat extraction stabilisation.
Especially, also new discovery of the inventor is CaO, SiO as the main component at powder
2, Na
2The composition that adds among the O is to MnO, B
2O
3, SrO, BaO, TiO
2, Fe
2O
3Deng studying, the result is B
2O
3Effect with the generation that suppresses the high-melting-point crystal.
Below, carry out detailed explanation with regard to the content of invention.
In the present invention, CaO is meant the Ca that contains in the powder all is scaled the resulting value of CaO.
The viscosity of moulding powder of the present invention under 1300 ℃ is set to 0.5poise～8poise.Be lower than in viscosity under the situation of 0.5poise, the powder that can not reduce fully in the molten steel is involved in.Preferred viscosities is more than the 2poise.On the other hand, under the situation of viscosity greater than 8poise, the even inflow property between crystallizer and the solidified shell is also insufficient.Preferred viscosities is below the 4poise.
As the viscosity measurement method of moulding powder, preferably use the rotor method.The moulding powder of measuring object is inserted in the crucible; After 10～15 minutes, put into vertical tube furnace (Elema resistance furnace) 1400 ℃ of following premelts, and the rotor of E type viscosimeter is immersed in the melted powder; After stablizing 30 minutes under 1300 ℃; Make the rotor rotation, measure the moment of torsion that causes because of the viscosity impedance, obtain viscosity.In addition, importantly E type viscosimeter will be proofreaied and correct with standard viscosity liquid in advance.
Moulding powder of the present invention is a benchmark with the quality, with CaO/SiO
2(following be designated as sometimes " basicity ") is set at 1.0～1.5.Be lower than at 1.0 o'clock in basicity, SiO
2Amount increases, and can not obtain the effect that is involved in because of reaction preventing of suppressing to cause.About SiO
2To the influence that is involved in, the back also will describe.On the other hand, basicity greater than 1.5 situation under, the fusing point of powder too raises; In powder, generating the high-melting-point crystal is cacoclasite; The mobile of melted powder significantly worsens, thus inflow property and lubricity guarantee the difficulty that becomes, the instability that becomes of the heat extraction in crystallizer simultaneously.
Secondly, describe with regard to the powder composition.
As the main component of powder, CaO, SiO are arranged
2As stated, with the basicity CaO/SiO in the powder
2Maintain 1.0～1.5th, very important.
As powder constituent of the present invention, importantly set the SiO in the powder
2Be 15 quality %～30 quality %, Na
2O is 2% quality～6 quality %, B
2O
3Be 1 quality %～4 quality %, and SiO
2, Na
2O and B
2O
3The summation of content be 20 quality %～40 quality %.
At this, SiO
2Being the main component that constitutes powder, is that the rerum natura that is used for melt temperature and viscosity etc. is adjusted necessary composition.And find recently: Na
2O, B
2O
3Have the glass property of raising, suppress to contain Al
2O
3The function of generation of high-melting-point crystal, and through and use Na
2O, B
2O
3, its effect obtains performance significantly.
Wherein, distinguish at SiO
2, Na
2O, B
2O
3In, all be when content is too much, take place easily owing to the reaction with molten steel becomes, thereby the problem that exists is that powder being involved in molten steel taken place.
Therefore, can know except SiO
2, Na
2O, B
2O
3The content of each composition beyond, also need stipulate SiO
2, Na
2O and B
2O
3The summation of content.
So, about SiO
2, Na
2O, B
2O
3The content and the SiO of each composition
2, Na
2O and B
2O
3The summation of content, the inventor has obtained the opinion to optimum scope through experiment.Below at length describe.
Work as SiO
2When content is lower than 15 quality %, because adjustment such as the rerum natura of melt temperature and viscosity etc. is very difficult, thereby must be more than 15 quality %.But, when surpassing 30 quality %, owing to be difficult to obtain the inhibitory effect of reaction of powder and molten steel, thereby being involved in property worsens.Powder of the present invention as stated owing in powder, contain the F composition more than the ormal weight wittingly, thereby SiO
2Activity lower.Therefore, SiO
2Even the upper limit be 30 quality %, also can suppress the reaction of powder and molten steel.
In contrast, not to contain the powder in the past of the F composition more than the ormal weight wittingly in powder because SiO
2Activity higher, even if thereby make SiO
2On be limited to 30 quality %, can not suppress the reaction of powder and molten steel.
Na
2O is in order to adjust fusing point, improve glass property, to suppress to contain Al
2O
3The generation of high-melting-point crystal add, but at Na
2When O content is lower than 2 quality %, can not obtain its effect.In addition, Na
2O since easily with molten steel in Al or Ti react, thereby at Na
2When O content surpasses 6 quality %, can not obtain preventing effect because of reacting being involved in of suppressing to cause.Na
2The preferred scope of O content is 3 quality %～4 quality %.
B
2O
3Be in order to adjust fusing point, improve glass property, to suppress to contain Al
2O
3The high-melting-point crystal generation, the heat extraction stabilisation in the crystallizer is added, but work as B
2O
3When content is lower than 1 quality %, can not obtain its effect.In addition, B
2O
3Because Al in easy and the molten steel or Ti reaction, thereby work as B
2O
3When content surpasses 4 quality %, can not obtain preventing effect because of reacting being involved in of suppressing to cause.B
2O
3The content preferred range is 2 quality %～4 quality %.Preferred B
2O
3Lower limit be 2.5 quality %.
In addition, the SiO in powder
2, Na
2O and B
2O
3The summation of content when being lower than 20 quality %, the rerum natura adjustment of melt temperature and viscosity etc. the difficulty that becomes can not satisfy the characteristic that should possess as above-mentioned powder.On the other hand, the SiO in powder
2, Na
2O and B
2O
3The summation of content when surpassing 40 quality %, the reaction that suppresses powder and the molten steel difficulty that becomes can not obtain preventing effect because of being involved in of causing of reaction inhibition.SiO
2, Na
2O and B
2O
3The preferred scope of summation of content be 30 quality %～40 quality %.
By the way, as stated, the inventor finds through test recently: through and use Na
2O, B
2O
3Thereby, have the glass property of raising and suppress to contain Al
2O
3The effect of this function of generation of high-melting-point crystal can bring into play significantly, good thus heat extraction can stably be implemented, thereby it is unusual that operations such as bleedout can not take place, and can implement stable operation.Its mechanism it be unclear that, but can think to result from through and use Na
2O, B
2O
3And some cooperative effect that produces.
As powder constituent of the present invention, CaO content is set at below the 40 quality %.When CaO content surpassed 40 quality %, setting temperature raise, and inflow property and lubricity suffer damage easily.
On the other hand, if CaO is very few, then viscosity rises, and lubricity reduces, because of rather than preferably.In addition, the adjustment of fusing point also becomes difficult.Therefore, CaO is preferably set to more than the 30 quality %.
As powder constituent of the present invention, Al
2O
3Content is set at 3 quality %～25 quality %.Al
2O
3Add in order to adjust setting temperature and viscosity, but the Al in powder
2O
3Content when being lower than 3 quality %, the adjustment effect of setting temperature etc. is less, and when surpassing 25 quality % because viscosity too increases, thereby inflow property suffers damage with lubricity, the heat extraction behavior instability that becomes.
Powder constituent of the present invention need be through adding CaF wittingly
2Or NaF and the content of F composition is set at below the 10 quality %.The F composition reduces the setting temperature of powder, and makes SiO
2Activity reduce.In addition, the viscosity of powder also reduces.F composition in the powder is when surpassing 10 quality %, and viscosity too reduces and powder is flowed into too much, thereby the strand quality worsens.In addition, CaF
2Separate out Deng crystallization, make the heat extraction behavior become unstable.The content of preferred F composition is below the 9 quality %.
On the other hand, if the content of the F composition in the powder is very few, promptly the content of the F composition in the powder is below the 2 quality %, then SiO
2Activity can not reduce.In addition, take place with Al and Ti and SiO in the molten steel shown in above-mentioned (1) formula, (2) formula
2Reaction.Consequently, the surface tension between molten steel and melted powder reduces significantly, takes place easily thereby powder being involved in molten steel becomes.
In addition, if the content of the F composition in the powder is below the 2 quality %, then the viscosity adjustment becomes difficult, and viscosity rises, thereby becomes insufficient lubrication.
The content of preferred F composition is below the 2.4 quality %.More preferably below the 3 quality %.
In addition, F is as compound, and though be take which kind of form situation all can, total above-mentioned F content is represented F content.
Through making powder become up to the present described composition, when being used for the casting of the fast strand of casting speed, powder of the present invention is specially suitable.This is to flow between crystallizer and the solidified shell easily because the powder of fusion becomes.
More than be necessary composition of powder of the present invention and content, but also can further contain following composition.
As powder constituent of the present invention, ZrO
2Content is preferably set to 2 quality %～10 quality %.ZrO
2Add more than the 2 quality % in order to ensure viscosity.On the other hand, the ZrO in powder
2When content surpassed 10 quality %, viscosity too rose, the lubricity variation.ZrO
2The preferred scope of content is below the 4 quality %.
As powder constituent of the present invention, SrO content is preferably set to 2.5 quality %～10 quality %.Through SrO being set at more than the 2.5 quality %, can suppress physics values such as setting temperature and viscosity with respect to the variation of powder constituent and change.On the other hand, when SrO content surpassed 10 quality %, manufacturing cost raise.The preferred scope of SrO content is below the 4 quality %.
Moreover, preferably in powder of the present invention, suitably contain carbonaceous or organic matters such as fiber and resin such as carbon black, coke blacking, graphite.This is because these carbonaceous or organic matter can be adjusted fusion speed, has the molten steel surface heat preservation effect.In addition, also because have function as the cement that is used to be shaped etc.
Each composition of above-mentioned powder can adopt fluorescent X-ray and chemical analysis to analyze resulting value.
Powder of the present invention is preferably formed more than its 50 quality % by the premelt base material.So-called premelt base material is meant that at high temperature a part of composition as powder stock being carried out melt process in advance obtains.Usually powder stock is heated to 1000～1400 ℃ and make its fusion.The premelt base material is under said temperature, to make with CaO-Al
2O
3-SiO
2For base and mixed Na
2O, B
2O
3, the material fusion of F etc. and concretionary., be why in order on the molten steel in mold liquid level, to make powder fusion equably with being set at the premelt base material more than the 50 quality %.Powder morphology of the present invention both can be a powder, also can be graininess.In addition, be more preferably environmental protection good and the heat insulating ability of molten steel and the good hollow particle shape of covering property.
In addition, the reaction of inhibition powder and molten steel has reduction Al simultaneously
2O
3Or TiO
2Denseization in powder, prevent that thereby viscosity from changing the effect can guarantee inflow property and lubricity.
At this, as the reference value of the reaction that suppresses powder and molten steel, also can be with the interfacial tension of powder as index.The higher limit of the interfacial tension between molten steel and powder does not have special qualification, but the higher person preferably.As adjustable numerical value in actual job, under 1550 ℃, be about 1.7N/m as target.At this, why interfacial tension is set at the numerical value under 1550 ℃, be because it is in the approaching temperature of liquid steel temperature that casts continuously with effective supply.
At this, the measurement of interfacial tension can adopt with " big well is great, wild rugged to be exerted, Ji Jingyu: iron と steel, 58(1972), p.890 " in the same method of record carry out.
Promptly; In can 1550 ℃ melted powder of fusion in crucible, add the steel sample lentamente and make the steel fusion, from laterally the molten steel shape the melted powder being carried out the radioscopy photography; And measure the shape of steel, thereby the interfacial tension of obtaining from this X line perspective photograph.
Can use the object steel grade of powder of the present invention effectively so long as in molten steel, contain at least a person among Al or the Ti, just not have special qualification.The steel grade that concentration of carbon is low, for example concentration of carbon be the steel grade of 0.0005～0.05 quality % in steel plate, result from the defective of powder easily.Therefore, in such steel grade, powder of the present invention is suitable.
In addition, in the present invention, the Al in the molten steel or the content of Ti are not constrained.That is to say,, also can obtain effect of the present invention fully even be below the 0.1 quality % and the lower molten steel of the content of Al or Ti uses under the situation of powder of the present invention at least a content of Al, Ti.
If it is the continuous casting of the ultra-low carbon steel of 0.01～0.07 quality % that powder of the present invention is applicable to the Ti concentration in the molten steel, then is preferred especially.This is because of this steel grade owing to implemented to force the worker, thereby preferably reduces the field trash in the steel as far as possible.
In addition, if powder of the present invention is applicable to that the Al concentration in the molten steel is the continuous casting of the ultra-low carbon steel of 0.01～0.07 quality %, then be preferred especially.This is because of this steel grade owing to implemented to force the worker, thereby preferably reduces the field trash in the steel as far as possible.
And if powder of the present invention is applicable to that the Al concentration in the molten steel surpasses the continuous casting of the high Al steel of 0.1 quality %, then is preferred especially.This is because this steel grade easy residual field trash in steel.
Embodiment
Below enumerate embodiment, carry out detailed explanation with regard to the present invention.
In vacuum refining furnace (RH), will be adjusted into the constituent concentration of regulation with the molten steel 300ton of converter melting, the molten steel that makes the ultra-low carbon steel that obtains like this uses vertical curve type continuous casting machine that it is cast as thickness to be 250mm, the width strand as 1600mm through tundish, submersed nozzle.Casting speed is set at 1.8m/min.
Table 1, table 2 (continuous table 1) have been represented Al, the Ti concentration in the molten steel of composition, physics value and casting of powder.Powder No.1～21, the 50th, the present invention's example.No.22～41, the 51st, comparative example.
In addition, the viscosity of powder is the numerical value under 1300 ℃, measures with above-mentioned method.
Carry out hot rolling, pickling, cold rolling and annealing with well-established law to casting resulting strand; Thereby process thin steel sheet for automobile; Observe surface and application form planar defect, carry out pressure processing simultaneously, the generation of inspection crackle; About blemish, pressure processing crackle, estimated the steel-sheet quality with its incidence.
In addition; About operation property; In crystallizer, set up thermocouple, the continuous measurement variations in temperature is with the stable situation of its variation of temperature " G (Good) ", the unsettled situation of variation of temperature with unusual these 2 levels of situation " P (Poor) " of operations such as bleedout have taken place estimate.
In addition; About overall merit; There not to be operation unusual and be the situation " VG (Very Good) " below 0.2% in blemish aspect the quality and pressure processing crackle sum; Do not have operation unusual and also aspect quality blemish and pressure processing crackle sum greater than 0.2 but smaller or equal to 0.4% situation " G (Good) ", take place operation unusual or aspect quality blemish and pressure processing crackle sum estimate greater than these 3 levels of situation " P (Poor) " of 0.4%.
Consequently, shown in table 1, table 2, in using continuous casting of the present invention, can't see fully unusually because of the operation that flows into bleedout alarm that instability causes and bleedout etc., in contrast, these operations are observed unusually in large quantities in comparative example.
Especially, with regard to SiO
2, Na
2O and B
2O
3These 3 one-tenth assign to see that the No.27 of comparative example, the 28th does not contain Na
2The situation of O, or situation about lacking than scope of the present invention, remaining SiO
2, B
2O
3Content and SiO
2, Na
2O and B
2O
3Even content summation within the scope of the invention, it is unusual also to produce operation.
In addition, the No.30 of comparative example, the 31st does not contain B
2O
3Situation under, or situation about lacking than scope of the present invention, remaining SiO
2, Na
2The content of O and SiO
2, Na
2O and B
2O
3Even content summation within the scope of the invention, it is unusual also to produce operation.
In contrast, as No.1～21 of the present invention in the scope of the present invention example and No.50 under any circumstance, operation also can't see unusually fully.
This can think: in comparative example, because Na
2O and B
2O
3Content outside scope of the present invention, thereby can not suppress the generation of high-melting-point crystal fully and heat extraction is worsened, in contrast, in example of the present invention, can suppress the generation of high-melting-point crystal fully, thereby can realize good heat extraction.
In addition, in the production board of the strand that uses the present invention's example, the cracking frequency when resulting from incidence and the pressure processing of blemish of powder reduces than comparative example significantly.
Specifically, use vertical curve type continuous casting equipment, but in flexure type and vertical-type continuous casting equipment, also can confirm same effect.In addition; Present embodiment just is illustrated about the instance of the strand manufacturing of thin steel sheet for automobile; But the place that becomes the essence of present technique is the heat extraction in the stable crystalline device; And prevent because of powder is involved in the defective that produces, when making the strand of other steel grades such as steel plate for tanks, steel pipe, also can confirm this effect.
In addition, foregoing only illustration embodiment of the present invention, the present invention can carry out various changes in claims.
Utilizability on the industry
As above-mentioned, according to the present invention, can high production rate ground make and do not result from the high-quality steel of defective of powder.Therefore, the present invention has higher value on industry.
Claims (2)
1. the continuous casting mold powder of a steel, the continuous casting that it is used for containing at least a steel of Al or Ti is characterized in that: CaO/SiO
2Be 1.0～1.5 by quality ratio, contain SiO
2Be 15 quality %～30 quality %, CaO is 30 quality %～40 quality %, Al
2O
3Be 3 quality %～25 quality %, Na
2O is 2 quality %～6 quality %, with CaF
2Or the F composition that NaF adds is greater than 2 quality % but smaller or equal to 10 quality %, B
2O
3Be 1 quality %～4 quality %, SiO
2, Na
2O and B
2O
3Quality % sum be 20 quality %～40 quality %, remainder comprises unavoidable impurities; Viscosity under 1300 ℃ is 0.5poise～8poise;
Wherein, CaO all is scaled CaO and the value that obtains with the Ca that contains in the powder.
2. the continuous casting mold powder of steel according to claim 1 is characterized in that: further contain ZrO
2: among 2 quality %～10 quality %, the SrO:2.5 quality %～10 quality % more than a kind.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010010841 | 2010-01-21 | ||
| JP2010-010841 | 2010-01-21 | ||
| PCT/JP2011/051679 WO2011090218A1 (en) | 2010-01-21 | 2011-01-21 | Mould powder for continuous casting of steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102712036A true CN102712036A (en) | 2012-10-03 |
| CN102712036B CN102712036B (en) | 2015-06-17 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201180006352.2A Active CN102712036B (en) | 2010-01-21 | 2011-01-21 | Mould powder for continuous casting of steel |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP4837804B2 (en) |
| KR (2) | KR20120092708A (en) |
| CN (1) | CN102712036B (en) |
| BR (1) | BR112012018248A2 (en) |
| WO (1) | WO2011090218A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105642847A (en) * | 2016-01-26 | 2016-06-08 | 中南大学 | Casting powder for continuous casting of low-carbon steel and application of casting powder |
| CN114130973A (en) * | 2021-12-13 | 2022-03-04 | 芜湖新兴铸管有限责任公司 | Special mold flux for crystallizer for inland natural service environment resistant corrosion-resistant steel bar and preparation method and application thereof |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102014108843A1 (en) * | 2014-06-24 | 2015-12-24 | Thyssenkrupp Ag | Casting powder, foundry slag and method of casting steel |
| JP6354411B2 (en) * | 2014-07-15 | 2018-07-11 | 新日鐵住金株式会社 | Mold flux for continuous casting |
| CN105537547B (en) * | 2016-02-25 | 2018-05-01 | 唐山市鑫焱昌科技有限公司 | The inexpensive high alkalinity crystallizer protecting residue of continuous casting peritectic steel |
| CN105710347A (en) * | 2016-05-05 | 2016-06-29 | 北京晶晶星科技有限公司 | Anti-oxidation protection flux for composite roll and preparation method of flux |
| KR102288415B1 (en) * | 2020-03-18 | 2021-08-10 | 주식회사 포스코 | Tundish flux and casting method using the same |
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| CN114130973A (en) * | 2021-12-13 | 2022-03-04 | 芜湖新兴铸管有限责任公司 | Special mold flux for crystallizer for inland natural service environment resistant corrosion-resistant steel bar and preparation method and application thereof |
| CN114130973B (en) * | 2021-12-13 | 2023-05-05 | 芜湖新兴铸管有限责任公司 | Application of special mold flux for crystallizer for corrosion-resistant steel bars |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4837804B2 (en) | 2011-12-14 |
| KR20150033733A (en) | 2015-04-01 |
| WO2011090218A1 (en) | 2011-07-28 |
| CN102712036B (en) | 2015-06-17 |
| KR20120092708A (en) | 2012-08-21 |
| JPWO2011090218A1 (en) | 2013-05-23 |
| BR112012018248A2 (en) | 2016-05-03 |
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