CN102712036B - Mould powder for continuous casting of steel - Google Patents
Mould powder for continuous casting of steel Download PDFInfo
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- CN102712036B CN102712036B CN201180006352.2A CN201180006352A CN102712036B CN 102712036 B CN102712036 B CN 102712036B CN 201180006352 A CN201180006352 A CN 201180006352A CN 102712036 B CN102712036 B CN 102712036B
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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 on the continuous casting mold powder of use crystallizer (casting mold) in.
Background technology
When casting molten steel continuously, the liquid steel level in crystallizer adds moulding powder (being sometimes designated as below " powder ").Powder requires following characteristic.
1) the melted powder layer formed by powder melting on liquid steel level and non-melted powder layer thereon cover liquid steel level, isolated with the contact of air, thus will have and prevent reoxidizing and carrying out the effect that is incubated of molten steel.
2) powder of melting is owing to must flow into as lubricant plays effect between crystallizer and solidified shell, thus will have the powder of often supply appropriate amount to adapt to the depletion rate of powder, thus reach the melting speed of the melted powder pond thickness of appropriate amount.
3) melted powder layer is absorbed in the non-metallic inclusion floated up in molten steel, and the change of its physical property (viscosity, melt temperature, setting temperature etc.) is little.
4) powder of melting flows between crystallizer and solidified shell, form uniform powder film, thus powder film will have lubrication between crystallizer and solidified shell.
5) powder of melting has suitable viscosity, interfacial tension, and the powder of melting can not be involved in molten steel.
In continuous casting operation, the liquid surface of local and the interface of the MOLTEN STEEL FLOW upset powder formed because of the injection stream being injected into the molten steel in crystallizer and molten steel, the powder of thus melting is involved in molten steel sometimes.
In addition, when casting continuously the molten steel containing Al or Ti, due to powder and the steel contacts of melting, Al or Ti thus in molten steel and the SiO as the main component in powder
2between there is following reaction.
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 molten steel, and () is the composition in melted powder.When producing reaction as described above between molten steel and melted powder interface, the interfacial tension between molten steel and melted powder reduces greatly, thus the powder in molten steel is involved in become and more easily occurs.
The major part being involved in the melted powder in molten steel floats up again, but its part is often solidified shell catches and remain on strand.The powder remaining in steel mesexine becomes the cord defects of product surface.In addition, the occurrence cause of pressure processing crackle is become at the powder of internal residual.These phenomenons easily occur when quick cast especially.In, low speed casting time, for the steel that the quality requirements such as tinplate material, automotive sheet are strict, these phenomenons usually become problem.
For this reason, as preventing powder to be involved in countermeasure in molten steel, develop following powder etc.: as Patent Document 1 there is the powder that high viscosity and the capillary difficulty of height be involved in; The powder that the difficulty with high interfacial tension shown in patent document 2 is involved in; Passing through shown in patent document 3 suppresses Al and Ti in molten steel and the SiO in powder
2reaction prevent the significantly reduction of the interfacial tension between molten steel and melted powder, thus suppress powder being involved in molten steel.
On the other hand, when the powder of melting is hindered to the inflow between the crystallizer and solidified shell of melted powder and damages lubrication, in crystallizer, the heat extraction (heat extraction) between solidified shell and crystallizer becomes unstable.Consequently, solidifying of strand becomes uneven, causes the generation of strand crackle, and then produces bleedout (breakout).Bleedout not only causes the reduction of operation stopping, output, and causes great infringement to continuous casting equipment.Therefore, solidify uniformity in order to what improve strand in crystallizer, thus prevent the generation of crackle and bleedout, the heat extraction stably in crystallization control device is very important.So, be developed the high viscosity and high alkalinity that both meet shown in patent document 4, in powder film, separate out stable crystallization again thus stably control the powder of heat extraction.
In addition, containing in Al steel, also exist because separate out high-melting-point crystal and cacoclasite in the powder, thus the heat extraction produced in insufficient lubrication or crystallizer becomes unstable problem.So, shown in patent document 5, develop and prevent the molten steel because of caused by the reaction of molten steel and powder from polluting, pass through Li simultaneously
2the interpolation of O and F and prevent the powder of the precipitation of high-melting-point crystal and cacoclasite.
Patent document 6 proposes a kind of powder, it is in the viscosity of the powder of molten condition by improving, make powder to the inflow between crystallizer and solidified shell for a small amount of and even, weaken the crystallization tendency of powder simultaneously, make the state of slag film become even, thus seek the homogenising of the heat extraction in crystallizer.
Moreover patent document 7 proposes a kind of powder, it makes powder contain ZrO
2, TiO
2and Cr
2o
3among more than one oxide, thus seek the homogenising of the heat extraction in crystallizer.
Prior art document
Patent document
Patent document 1: Japanese Unexamined Patent Publication 2-25254 publication
Patent document 2: Japanese Unexamined Patent Publication 2000-071051 publication
Patent document 3: Japanese Unexamined Patent Publication 2008-264791 publication
Patent document 4: Japanese Unexamined Patent Publication 2005-040835 publication
Patent document 5: Japanese Unexamined Patent Publication 2006-110578 publication
Patent document 6: International Publication WO00/33992 pamphlet
Patent document 7: Japanese Unexamined Patent Publication 8-33962 publication
Summary of the invention
Invent problem to be solved
But, in order to adapt to the requirement of further quick cast and Quality advance, as the powder recorded in patent document 1, if just change powder constituent to prevent from being involved in and make it high viscosity, then can not guarantee the suitable powder influx between crystallizer and solidified shell, thus can not lubricity be maintained.In addition, the possibility of bleedout is caused to get rid of completely.
In the powder described in patent document 2, due to CaO/SiO
2very high, reach more than 7, thus setting temperature raises, and can not guarantee the influx of suitable powder, thus can not maintain the lubricity between crystallizer and solidified shell.Therefore, the possibility causing bleedout can not be got rid of completely.In addition, due to the SiO in powder
2amount is few, Al
2o
3amount is many, thus separates out high-melting-point crystal and cacoclasite, thus likely hinders lubrication, makes the heat extraction in crystallizer become unstable simultaneously.
In the powder described in patent document 3, because viscosity is large, thus damages to the uniform inflow between crystallizer and solidified shell, sufficient lubricity can not be maintained.Therefore, the possibility causing bleedout can not be got rid of completely.In addition, owing to containing a large amount of Al in order to ensure viscosity
2o
3, thus separate out high-melting-point crystal and cacoclasite, thus likely make heat extraction become unstable.
In the powder described in patent document 4, owing to making high-melting-point crystal and cacoclasite etc. separate out energetically, thus likely hinder inflow and the lubricity of powder, make the heat extraction of high-melting-point crystal in crystallizer become unstable simultaneously.
In the powder described in patent document 5, the precipitation of high-melting-point crystal and cacoclasite is suppressed, but the Li contained in powder
2al and Ti in O and molten steel reacts and interfacial tension is reduced, thus there is powder and be easily involved in possibility in molten steel.
Like this, in the powder described in patent document 1 ~ 5, take into account and prevent powder to be involved in molten steel and heat extraction in stability contorting crystallizer is very difficult.
In addition, in the powder described in patent document 6, reduce F composition and improve viscosity.Therefore, the powder influx of melting also can be less, and Problems existing is the casting that can only be applicable to bloom and steel billet.
And the powder recorded in patent document 7 contains ZrO
2, TiO
2and Cr
2o
3, hinder melted powder radiant heat transmission in the liquid phase, thus scattering or absorption radiation of heat in the liquid phase.Therefore, there is the heat-labile problem of row in crystallizer.
The present invention completes in view of such situation, its object is to the continuous casting powder that a kind of steel is provided, it is by suppressing the reaction of molten steel and powder, inhibit powder to being involved in molten steel, thus can not resulted from the product of high-quality of defect of powder, and the heat extraction in crystallizer is stablized, thus productivity ratio can not be hindered.
For solving the means of problem
Main points of the present invention for solving above-mentioned problem are as follows:
(1) a continuous casting mold powder for steel, it, for the continuous casting of the steel containing at least one in Al or Ti, is characterized in that: CaO/SiO
2be 1.0 ~ 1.5 by quality ratio, containing SiO
2be 15 quality % ~ 30 quality %, CaO be 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 is less than 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 inevitable impurity; Viscosity at 1300 DEG C is 0.5poise ~ 8poise.
Wherein, CaO is the value Ca contained in powder being all scaled CaO and obtaining.
(2) the continuous casting mold powder of the steel according to above-mentioned (1), is characterized in that: further containing ZrO
2: more than a kind among 2 quality % ~ 10 quality %, SrO:2.5 quality % ~ 10 quality %.
The effect of invention
According to the present invention, a kind of continuous casting powder of steel can be provided, even if it is when casting continuously with the molten steel containing Al or Ti, by suppressing the reaction of molten steel and powder, also inhibits powder to being involved in molten steel, thus can not resulted from the product of high-quality of defect of powder, and the heat extraction in crystallizer is stablized, thus can not productivity ratio be hindered.
Detailed description of the invention
Along with the quickening of casting speed, the powder in molten steel is involved in increase, thus produces cord defects and the such defect resulting from powder of pressure processing crackle, so preferably use is more difficult to produce the powder that powder is involved in.But in the above-mentioned powder be involved in difficulty for target, Problems existing is owing to separating out high-melting-point crystal, thus can not maintain the sufficient lubricity between crystallizer and solidified shell, thus heat extraction becomes unstable.
So the present inventor, when using the molten steel containing Al or Ti to cast continuously, in order to prevent the powder in molten steel to be involved in, can carry out the stability contorting of the heat extraction in crystallizer, repeatedly having carried out research with great concentration to it simultaneously.
Consequently, the present inventor finds recently: if make the F composition wittingly containing ormal weight in powder, then the fusing point of powder declines, and SiO
2activity reduce.In addition, the present inventor's also new discovery: by reducing SiO
2activity, above-mentioned (1) formula, the molten steel represented by (2) formula and SiO
2reaction would not occur, thus powder be involved in become be difficult to occur.
In addition, the present inventor's also new discovery, if the B in the powder containing ormal weight
2o
3, then also can suppress the generation of high-melting-point crystal, there will not be that to result from the heat extraction of high-melting-point crystal unstable, thus make heat extraction stabilisation.
Especially, the present inventor's also new discovery, as at the main component of powder and CaO, SiO
2, Na
2the composition added in O, to MnO, B
2o
3, SrO, BaO, TiO
2, Fe
2o
3etc. being studied, result is B
2o
3there is the effect of the generation suppressing high-melting-point crystal.
Below, the content with regard to invention is described in detail.
In the present invention, CaO refers to the value Ca contained in powder being all scaled CaO and obtaining.
The viscosity of moulding powder of the present invention at 1300 DEG C is set to 0.5poise ~ 8poise.When viscosity is lower than 0.5poise, can not be involved in by the powder reduced fully in molten steel.Preferred viscosities is more than 2poise.On the other hand, when viscosity is greater than 8poise, the even inflow between crystallizer and solidified shell is also insufficient.Preferred viscosities is below 4poise.
As the Viscosity Measurement Methods of moulding powder, preferably use eddy-canister viscometer.The moulding powder of measuring object is inserted in crucible, at 1400 DEG C, premelt is after 10 ~ 15 minutes, put into vertical tube furnace (Elema resistance furnace), and the rotor of E type viscosimeter is immersed in melted powder, stablize 30 minutes at 1300 DEG C after, rotor is rotated, measures the moment of torsion because viscous resistance causes, obtain viscosity.In addition, importantly E type viscosimeter corrects with standard viscosity liquid in advance.
Moulding powder of the present invention is benchmark with quality, by CaO/SiO
2(being sometimes designated as below " basicity ") is set as 1.0 ~ 1.5.Basicity lower than 1.0 time, SiO
2amount increases, and can not obtain the effect preventing being involved in because response inhabitation causes.About SiO
2on the impact be involved in, after also will be described.On the other hand, when basicity is greater than 1.5, the fusing point of powder too raises, generate high-melting-point crystal and cacoclasite in the powder, the mobility of melted powder significantly worsens, thus inflow property and lubricity guarantee become difficulty, the heat extraction simultaneously in crystallizer becomes unstable.
Secondly, be described with regard to powdered ingredients.
As the main component of powder, there are CaO, SiO
2.As mentioned above, by the basicity CaO/SiO in powder
2it is very important for maintaining 1.0 ~ 1.5.
As powder constituent of the present invention, importantly set the SiO in 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 form the main component of powder, is adjust necessary composition for the physical property of melt temperature and viscosity etc.And recently find: Na
2o, B
2o
3have improve glassy, suppress containing Al
2o
3the function of generation of high-melting-point crystal, and pass through and use Na
2o, B
2o
3, played its successful.
Wherein, distinguished at SiO
2, Na
2o, B
2o
3in, be all when content is too much, owing to becoming easy generation with the reaction of molten steel, thus Problems existing powder occurs to being involved in molten steel.
Therefore, known except SiO
2, Na
2o, B
2o
3each composition content beyond, also need regulation SiO
2, Na
2o and B
2o
3the summation of content.
So, about SiO
2, Na
2o, B
2o
3the content of each composition and SiO
2, Na
2o and B
2o
3the summation of content, the present inventor obtains the opinion to most suitable scope by experiment.Below be described in detail.
Work as SiO
2when content is lower than 15 quality %, because the physical property adjustment of melt temperature and viscosity etc. is very difficult, thus must at more than 15 quality %.But when more than 30 quality %, owing to being difficult to the inhibitory effect of reaction obtaining powder and molten steel, being thus involved in property worsens.Powder of the present invention is described above, owing to containing the F composition of more than ormal weight in the powder wittingly, thus SiO
2activity lower.Therefore, SiO
2even if the upper limit be 30 quality %, also can suppress the reaction of powder and molten steel.
In contrast, not that the powder in the past of the F composition containing more than ormal weight is wittingly due to SiO in the powder
2activity higher, even if thus make SiO
2the upper limit be 30 quality %, the reaction of powder and molten steel can not be suppressed.
Na
2o be in order to adjust fusing point, improve glassy, suppress containing Al
2o
3the generation of high-melting-point crystal add, but at Na
2when O content is lower than 2 quality %, its effect can not be obtained.In addition, Na
2o reacts, thus at Na due to Al or Ti easily and in molten steel
2when O content is more than 6 quality %, what can not obtain causing because of response inhabitation is involved in preventing effectiveness.Na
2the preferred scope of O content is 3 quality % ~ 4 quality %.
B
2o
3be in order to adjust fusing point, improve glassy, suppress containing Al
2o
3high-melting-point crystal generation, the heat extraction stabilisation in crystallizer is added, but work as B
2o
3when content is lower than 1 quality %, its effect can not be obtained.In addition, B
2o
3because Al or Ti easily and in molten steel reacts, thus work as B
2o
3when content is more than 4 quality %, what can not obtain causing because of response inhabitation is involved in preventing effectiveness.B
2o
3the preferred scope of content is 2 quality % ~ 4 quality %.Preferred B
2o
3lower limit be 2.5 quality %.
In addition, as the SiO in powder
2, Na
2o and B
2o
3the summation of content lower than 20 quality % time, the physical property adjustment of melt temperature and viscosity etc. becomes difficulty, can not meet the characteristic that should possess as above-mentioned powder.On the other hand, as the SiO in powder
2, Na
2o and B
2o
3the summation of content more than 40 quality % time, suppress the reaction of powder and molten steel to become difficulty, what can not obtain causing because of response inhabitation is involved in preventing effectiveness.SiO
2, Na
2o and B
2o
3the preferred scope of summation of content be 30 quality % ~ 40 quality %.
By the way, as mentioned above, the present inventor by test recently find: by and use Na
2o, B
2o
3, have and improve glassy thus suppress containing Al
2o
3the effect of this function of generation of high-melting-point crystal can bring into play significantly, heat extraction good thus can stably be implemented, and thus the operations such as bleedout can not occur abnormal, can implement stable operation.Its mechanism it be unclear that, but can think result from by and use Na
2o, B
2o
3and some cooperative effect produced.
As powder constituent of the present invention, CaO content is set as below 40 quality %.When CaO content is more than 40 quality %, setting temperature raises, and inflow property and lubricity easily suffer damage.
On the other hand, if CaO is very few, then viscosity rises, and lubricity reduces, because of instead of preferably.In addition, the adjustment of fusing point also becomes difficulty.Therefore, CaO is preferably set to more than 30 quality %.
As powder constituent of the present invention, Al
2o
3content is set as 3 quality % ~ 25 quality %.Al
2o
3add to adjust setting temperature and viscosity, but as the Al in powder
2o
3content lower than 3 quality % time, the Adjustment effect of setting temperature etc. is less, and when more than 25 quality %, and because viscosity too increases, thus inflow property and lubricity suffer damage, and heat extraction behavior becomes unstable.
Powder constituent of the present invention needs by adding CaF wittingly
2or NaF and make the content of F composition be set as below 10 quality %.F composition makes the setting temperature of powder reduce, and makes SiO
2activity reduce.In addition, the viscosity of powder also reduces.F composition in powder is when more than 10 quality %, and viscosity too reduces and makes powder flow into too much, thus Slab quality worsens.In addition, CaF
2deng crystallization, heat extraction behavior is made to become unstable.The content of preferred F composition is below 9 quality %.
On the other hand, if the content of the F composition in powder is very few, the content of the F composition namely in powder is below 2 quality %, then SiO
2activity can not reduce.In addition, occur with the Al in the molten steel shown in above-mentioned (1) formula, (2) formula and Ti and SiO
2reaction.Consequently, the surface tension between molten steel and melted powder significantly reduces, thus powder becomes easy generation to being involved in molten steel.
In addition, if the content of the F composition in powder is below 2 quality %, then viscosity adjustment becomes difficulty, and viscosity rises, thus becomes insufficient lubrication.
The content of preferred F composition is below 2.4 quality %.More preferably below 3 quality %.
In addition, F as compound, no matter be the situation taking which kind of form, total above-mentioned F content represents F content.
By the composition making powder become up to the present described, when the casting for the fast strand of casting speed, powder of the present invention is specially suitable.Easily flow between crystallizer and solidified shell this is because the powder of melting becomes.
More than the necessary composition of powder of the present invention and content, but also can further containing following composition.
As powder constituent of the present invention, ZrO
2content is preferably set to 2 quality % ~ 10 quality %.ZrO
2more than 2 quality % are added in order to ensure viscosity.On the other hand, as the ZrO in powder
2when content is more than 10 quality %, viscosity too rises, and lubricity is deteriorated.ZrO
2the preferred scope of content is below 4 quality %.
As powder constituent of the present invention, SrO content is preferably set to 2.5 quality % ~ 10 quality %.By SrO is set as more than 2.5 quality %, the physics value such as setting temperature and viscosity can be suppressed to change relative to the change of powder constituent.On the other hand, when SrO content is more than 10 quality %, manufacturing cost raises.The preferred scope of SrO content is below 4 quality %.
Moreover, preferably in powder of the present invention, suitably containing carbonaceous or the organic matters such as fiber and resin such as carbon black, coke blacking, graphite.This is because these carbonaceous or organic matter can adjust melting speed, there is the effect to molten steel surface insulation.In addition, also because have the function as the cement for being shaped etc.
Each composition of above-mentioned powder can adopt fluorescent X-ray and chemical analysis to carry out analyzing obtained value.
Powder of the present invention is preferably formed its more than 50 quality % by premelt base material.So-called premelt base material, refers to that at high temperature carrying out melt process to a part of composition as powder stock in advance obtains.Usually powder stock be heated to 1000 ~ 1400 DEG C and make its melting.Premelt base material makes with CaO-Al at the temperature disclosed above
2o
3-SiO
2na is mixed with for base
2o, B
2o
3, the material molten of F etc. concretionary.Why more than 50 quality % being set as premelt base material, is to make powder melting equably on molten steel in mold liquid level.Powder morphology of the present invention both can be powder, also can be graininess.In addition, the excellent and heat insulating ability of molten steel of environmental protection and the excellent hollow particle shape of covering is more preferably.
In addition, suppress the reaction of powder and molten steel to have reduction Al simultaneously
2o
3or TiO
2denseization in the powder, prevent viscosity B coefficent thus inflow property and the effect of lubricity can be guaranteed.
At this, as the reference value of reaction suppressing powder and molten steel, also can using the interfacial tension of powder as index.The higher limit of the interfacial tension between molten steel and powder is not particularly limited, but preferably the higher person.As numerical value adjustable in actual job, be about 1.7N/m as target at 1550 DEG C.At this, why interfacial tension being set as the numerical value at 1550 DEG C, is because it is in the close temperature of the liquid steel temperature that casts continuously with effective supply.
At this, the measurement of interfacial tension can adopt with " large well is great, wild rugged to be exerted, Ji Jingyu: iron と Steel, 58(1972), the same method recorded p.890 " is carried out.
Namely, in the melted powder of 1550 DEG C of melting in crucible, steel curved beam can be added lentamente and make steel melting, from laterally carrying out X-ray radiographic to the molten steel shape melted powder, and measure the shape of steel from this X-ray examination photo, thus obtain interfacial tension.
As long as the object steel grade of powder of the present invention effectively can be used in molten steel containing at least one person in Al or Ti, be just not particularly limited.The steel grade that concentration of carbon is low, such as concentration of carbon be the steel grade of 0.0005 ~ 0.05 quality % in steel plate, easily result from the defect of powder.Therefore, in such steel grade, powder of the present invention is suitable.
In addition, in the present invention, the content of Al or Ti in molten steel is not circumscribed.That is, even if when the content of at least one of Al, Ti is below 0.1 quality % and the low molten steel of the comparision contents of Al or Ti uses powder of the present invention, also effect of the present invention can be obtained fully.
If the powder of the present invention Ti concentration be applicable in molten steel is the continuous casting of the ultra-low carbon steel of 0.01 ~ 0.07 quality %, be then particularly preferred.This is because this steel grade forces work owing to being implemented, thus preferably reduce the field trash in steel as far as possible.
In addition, if the powder of the present invention Al concentration be applicable in molten steel is the continuous casting of the ultra-low carbon steel of 0.01 ~ 0.07 quality %, be then particularly preferred.This is because this steel grade forces work owing to being implemented, thus preferably reduce the field trash in steel as far as possible.
And if powder of the present invention is applicable to the continuous casting of the Al concentration in molten steel more than the high Al steel of 0.1 quality %, be then particularly preferred.This is because this steel grade easily remains field trash in steel.
Embodiment
Below enumerate embodiment, just the present invention is described in detail.
The constituent concentration of regulation will be adjusted to the molten steel 300ton of converter melting in vacuum refining furnace (RH), make the molten steel of the ultra-low carbon steel obtained like this through tundish, submersed nozzle and be cast as with vertical curve type continuous casting machine that thickness is 250mm, width is the strand of 1600mm.Casting speed is set as 1.8m/min.
Table 1, table 2(continued 1) illustrate Al, Ti concentration in the molten steel of the composition of powder, physics value and casting.Powder No.1 ~ 21,50 are the present invention's examples.No.22 ~ 41,51 are comparative examples.
In addition, the viscosity of powder is the numerical value at 1300 DEG C, measures by above-mentioned method.
Hot rolling, pickling, cold rolling and annealing is carried out to casting the strand obtained with well-established law, thus make thin steel sheet for automobile, observe surface and application form planar defect, carry out pressure processing simultaneously, check the generation of crackle, about blemish, pressure processing crackle, have rated steel-sheet quality by its incidence.
In addition, about workability, in crystallizer, set up thermocouple, continuous measurement variations in temperature, evaluate with the situation of the change instability of the situation of the vary stable of its temperature " G(Good) ", temperature and situation " P(Poor) " these 2 levels of there occurs the operation exceptions such as bleedout.
In addition, about overall merit, with do not have operation abnormal and also in quality blemish and pressure processing crackle sum be the situation " VG(Very Good) " of less than 0.2%, do not have operation abnormal and also in quality blemish and pressure processing crackle sum be greater than 0.2 but be less than or equal to the situation " G(Good) " of 0.4%, there are abnormal or that blemish and pressure processing crackle sum are greater than 0.4% in quality situation " P(Poor) " these 3 levels of operation and evaluate.
Consequently, as shown in table 1, table 2, in use continuous casting of the present invention, can't see completely because the operation flowing into bleedout alarm that instability causes and bleedout etc. is abnormal, in contrast, these operations are abnormal is in a comparative example observed in large quantities.
Especially, with regard to SiO
2, Na
2o and B
2o
3these 3 one-tenth assign to see, the No.27,28 of comparative example is not containing Na
2the situation of O, or the situation fewer than scope of the present invention, remaining SiO
2, B
2o
3content and SiO
2, Na
2o and B
2o
3even if content summation within the scope of the invention, it is abnormal also to produce operation.
In addition, the No.30,31 of comparative example is not containing B
2o
3when, or the situation fewer than scope of the present invention, remaining SiO
2, Na
2the content of O and SiO
2, Na
2o and B
2o
3even if content summation within the scope of the invention, it is abnormal also to produce operation.
In contrast, as No.1 ~ 21 of the example of the present invention in scope of the present invention and No.50 under any circumstance, operation is abnormal also be can't see completely.
This can think: in a comparative example, due to Na
2o and B
2o
3content outside scope of the present invention, thus can not suppress the generation of high-melting-point crystal fully and heat extraction be worsened, in contrast, in example of the present invention, the generation of high-melting-point crystal can be suppressed fully, thus good heat extraction can be realized.
In addition, in the production board of strand using example of the present invention, result from the incidence of blemish of powder and pressure processing time cracking frequency reduce significantly than comparative example.
Specifically, employ vertical curve type continuous casting equipment, but in flexure type and vertical-type continuous casting equipment, also can confirm same effect.In addition, the present embodiment is just illustrated about the example of the strand manufacture of thin steel sheet for automobile, but the place becoming the essence of this technology is the heat extraction in stable crystalline device, and prevent the defect that produces because powder is involved in, also can confirm this effect when making the strand of other steel grade such as steel plate for tanks, steel pipe.
In addition, foregoing is only exemplified with embodiments of the present invention, and the present invention can carry out various change in detail in the claims.
Utilizability in industry
As described above, according to the present invention, can make and not result from the high-quality steel of defect of powder in high production rate ground.Therefore, the present invention industrially has higher value.
Claims (2)
1. a continuous casting mold powder for steel, it, for the continuous casting of the steel containing at least one in Al or Ti, is characterized in that: CaO/SiO
2be 1.24 ~ 1.5 by quality ratio, containing SiO
2be 15 quality % ~ 30 quality %, CaO be 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 is less than 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 is inevitable impurity; Viscosity at 1300 DEG C is 0.5poise ~ 8poise;
Wherein, CaO is the value Ca contained in powder being all scaled CaO and obtaining.
2. a continuous casting mold powder for steel, it, for the continuous casting of the steel containing at least one in Al or Ti, is characterized in that: CaO/SiO
2be 1.24 ~ 1.5 by quality ratio, containing SiO
2be 15 quality % ~ 30 quality %, CaO be 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 is less than 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 %, further containing ZrO
2: more than a kind among 2 quality % ~ 10 quality %, SrO:2.5 quality % ~ 10 quality %, remainder is inevitable impurity; Viscosity at 1300 DEG C is 0.5poise ~ 8poise;
Wherein, CaO is the value Ca contained in powder being all scaled CaO and obtaining.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010-010841 | 2010-01-21 | ||
| JP2010010841 | 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 CN102712036A (en) | 2012-10-03 |
| CN102712036B true CN102712036B (en) | 2015-06-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201180006352.2A Active CN102712036B (en) | 2010-01-21 | 2011-01-21 | Mould powder for continuous casting of steel |
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| Country | Link |
|---|---|
| JP (1) | JP4837804B2 (en) |
| KR (2) | KR20150033733A (en) |
| CN (1) | CN102712036B (en) |
| BR (1) | BR112012018248A2 (en) |
| WO (1) | WO2011090218A1 (en) |
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| 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 |
| 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 |
| 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 |
| 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 |
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| JPH10263767A (en) * | 1997-03-21 | 1998-10-06 | Kawasaki Steel Corp | Method for continuously casting extra-low carbon steel and mold powder for continuous casting |
| JP2004148376A (en) * | 2002-10-31 | 2004-05-27 | Nippon Steel Corp | Powder for continuously casting steel |
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| CN1049117A (en) * | 1989-07-31 | 1991-02-13 | 重庆大学 | Presmelting vitrification continuous casting protective slag and production technology thereof |
| JP3004657B2 (en) * | 1989-08-14 | 2000-01-31 | 新日本製鐵株式会社 | Powder and casting method for casting high aluminum content steel |
| JP4265285B2 (en) * | 2003-05-29 | 2009-05-20 | Ｊｆｅスチール株式会社 | Mold powder for continuous casting of steel |
| JP4486878B2 (en) * | 2004-12-22 | 2010-06-23 | 新日本製鐵株式会社 | Mold powder for continuous casting of steel and continuous casting method |
| JP4903622B2 (en) * | 2007-04-16 | 2012-03-28 | 新日本製鐵株式会社 | Mold powder for continuous casting of steel and continuous casting method |
| JP5226423B2 (en) * | 2008-08-12 | 2013-07-03 | 日鐵住金建材株式会社 | Powder for continuous casting of steel |
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2011
- 2011-01-21 KR KR20157004455A patent/KR20150033733A/en active Search and Examination
- 2011-01-21 WO PCT/JP2011/051679 patent/WO2011090218A1/en active Application Filing
- 2011-01-21 CN CN201180006352.2A patent/CN102712036B/en active Active
- 2011-01-21 KR KR1020127018287A patent/KR20120092708A/en active Application Filing
- 2011-01-21 JP JP2011518098A patent/JP4837804B2/en active Active
- 2011-01-21 BR BR112012018248A patent/BR112012018248A2/en not_active Application Discontinuation
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| JPH10263767A (en) * | 1997-03-21 | 1998-10-06 | Kawasaki Steel Corp | Method for continuously casting extra-low carbon steel and mold powder for continuous casting |
| JP2004148376A (en) * | 2002-10-31 | 2004-05-27 | Nippon Steel Corp | Powder for continuously casting steel |
| CN101096049A (en) * | 2006-06-28 | 2008-01-02 | 宝山钢铁股份有限公司 | Low-contamination type continuous casting protection slag |
| CN101612653A (en) * | 2008-06-23 | 2009-12-30 | 宝山钢铁股份有限公司 | Mold powder for continuous casting of high aluminium-titanium-rare earth steel |
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Also Published As
| Publication number | Publication date |
|---|---|
| KR20120092708A (en) | 2012-08-21 |
| JP4837804B2 (en) | 2011-12-14 |
| CN102712036A (en) | 2012-10-03 |
| JPWO2011090218A1 (en) | 2013-05-23 |
| KR20150033733A (en) | 2015-04-01 |
| BR112012018248A2 (en) | 2016-05-03 |
| WO2011090218A1 (en) | 2011-07-28 |
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