CA1036825A - Flux for continuous casting of steel - Google Patents
Flux for continuous casting of steelInfo
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- CA1036825A CA1036825A CA232,685A CA232685A CA1036825A CA 1036825 A CA1036825 A CA 1036825A CA 232685 A CA232685 A CA 232685A CA 1036825 A CA1036825 A CA 1036825A
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- flux
- oxide
- steel
- continuous casting
- flowidity
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- Treatment Of Steel In Its Molten State (AREA)
Abstract
A B S T R A C T
A substantially entirely vitrified flux composition having flowidity and plastic deformation point suitable for use in the continuous casting of steel consists essentially of controlled proportions of alkali metal oxide, silica, calcium oxide, fluorine, and oxide of a Period IV total having Atomic Number of 23-28, inclusive, desirably with phosphorous pentoxide and titanium dioxide. In a process for continuous casting of steel the expos-ed molten metal surface is covered with a layer of such composition.
A substantially entirely vitrified flux composition having flowidity and plastic deformation point suitable for use in the continuous casting of steel consists essentially of controlled proportions of alkali metal oxide, silica, calcium oxide, fluorine, and oxide of a Period IV total having Atomic Number of 23-28, inclusive, desirably with phosphorous pentoxide and titanium dioxide. In a process for continuous casting of steel the expos-ed molten metal surface is covered with a layer of such composition.
Description
~03682S
The present invention relates to improvements in flux compositions for continuous casting of steel, and to such process using such flux.
Various steels such as high quality deoxidized carbon steel and certain stainless steels can be and often are now made by the process of continuous casting. In such manufacture inclusions of various materials such as oxides, silicates, and aluminates are particularly undesirable because they can give rise to surface or subsurface defects. Additionally, the mold desirably is protected at the top from attack by oxygen using a slag or flux.
Such slag or flux can help to suppress the formation of these undesirable inclusions, as well as to lubricate the steel as it is going through the mold and to affect heat transfer from the hot steel to the cooled mold.
A desirable flux composition for such continuous casting must possess chemical and thermal stability during contact with the molten steel in order to avoid generation of appreciable quantities of objectionable fumes, toxic gases, decomposition products, or by-products which might harm personnel or contaminate the product. Thus, lead-providing material in appreciable proportion is not used. Often such flux composition is called on to solubilize some of the impurities such as oxides, silicates, or aluminates which are believed to be the cause of most surface or subsurface imperfections found in continuous castings or in formed materials produced therefrom. The flux com-position should have a softening point (or a plastic deformation point) and a flowidity such that the layer of flux on the molten steel maintains its effectiveness during the casting process. Various fluxing and refractory ingredients can be tolerated in small proportions in the resulting steel in some cases; in other instances they must be low or absent to suppress transfer to the steel. Hence, aluminum-providing material in a flux is undesirable for use with some aluminum-killed steels, but can be used with the casting of other steels; various Period IV metal-providing materials can be tolerated in fluxes for steels normally containing them; occasionally boron oxide is un-desirable in fluxes for various steel.
., - 1 - ~
ib368zs Halley, in his ~nited States patent 3,649,249, discloses a synthetic slag composition e~inently suitable for use in the continuous casting of aluminum-killed steel, said slag having the composition: silica 10 to 5S%, calcia 0 to 40%, calcium fluoride 5 to 40%, sodium oxide and potassium oxide 5 to 35%, lithium oxide and lithium fluoride 0.5 to 15%, boria 0 to 30%; with the provision that the boria, calcium fluoride and lithium fluoride represent in combination, more than 15% of the composition, all percentages being by weight. Halley also characterizes his slag composition as having several particular properties: specific flowidity and plastic deformation point, both of which can be determined by standarized methods shown in the patent, and solubility of alumina therein in excess of 20%.
~xtensive testing of Halley's synthetic slag has shown it to be superior to any of the heterogeneous prior art slag (flux) compositions for suppressing the incidence of surface defects on such steels made by continuous casting; nevertheless, defects to the extent of about 10 percent often occur with such slag. Fortunately, such defects are not entirely of a serious type. However, even minor defects are undesirable because they require additional time, cost, and effort for correction.
Fluxes made in accordance with the present invention have been found quite efficient in the continuous casting of various steels. For elimin-ating defects they compare favorably with those heretofor produced. They can also be made to reduce attack on alumina-graphite molten metal inlet tubes ~shrouds) to the oQntinuous caster. Furthermore, the alumina content of the instant fluxes can be adjusted within the limits stated herein to further sup-press alumina solubility from the metal at modest sacrifice in raising fusion temperature and lowering flowidity of the flux. The instant flux compositions do not appear to form undesirable immiscible liquid phases at the elevated continuous casting temperatures.
An important distinction here from my prior work, Canadian patent applicatio~ 180,865 filed September 12, 1973, and from the Halley patent, is 10;~682S
the incorporation of an oxide of a Period IV metal having Atomic Number of 23 - 28, inclusive. Such inclusion reduces the softening point of the flux and increases flowidity, thus giving the flux desirable flowidity even though it contains refractory ingredients in appreciable proportions. Another adva~-tageous feature of the instant flux is the inclusion of a relatively small proportion of titanium dioxide. In small proportion ~less than about 4%) such inclusion tends to increase flowidity and reduce softening temperature of the flux, but as larger proportions of titanium dioxide are added up to the limits stated, viscosity of the flux is increased and this tends to reduce flowidity for controlling the balance of flowidity with the other desirable properties.
The flux composition according to the present invention is sub-stantially entirely in the vitreous state as frit particles, has flowidity and plastic deformation point suitable for use in the continuous casting of steel, and consists essentially of:
Advantageously Ingredient Broadly Wt. % Wt. %
Na20 6-25 8-23 Li20 0-8 3-7 SiO2 5-40 20-36 Mgo 0-20 0-10 CaO 5-30 8-30 BaO 0-20 0-10 SrO 0-20 0-10 Oxide of Period IV
metal having Atomic Number of 23-28, inclusive 1-10 1-6 TiO2 0-6 1-4 Zr2 0-5 0-3 1036~12S
In a process for the continuous casting of steel using an open-ended mold, the invention also provides the improvement which comprises cover-ing the exposed surface of the molten metal with a layer of such flux com-position (usually handled by scoop and maintained several inches thick).
When the foregoing compositional limitations are complied with, the flux flowidity will be in the usual range for continuous casting of steel (i.e., about 2" - 16" as measured according to United States patent 3,649,249) and advantageously about 6" - 10". Similarly the Plastic Deformation Point of the flux will be between about 1000 and about 1500 ., useful for continuous casting of steel. The alumina solubility will be at most about 15 - 17%
measured in accordance with the test shown in United States patent 3,649,249.
If the flux composition contains alumina, the alumina solubility will be diminished correspondingly.
While it is possible to use very small proportions (30% or less of the frit) of finely ground additives with the frit, which additives can smelt down in the caster to augment the composition within the limits stated, the flux as all frit appears to operate the best and most reliably in the con-tinuous casting of steel. The frit can be used as directly fritted or can be ground and classified according to desired size ranges. Usually it is cheaper to use the frit as it is fritted by quenching from a smelter operation.
The flux compositions can be smelted from actual oxides or pre-ferably for economy from their conventional ceramic raw material equivalents.
For example, some raw materials can be used to provide one or more ingredients of the flux such as sodium silicate which can provide sodium oxide as well as silicon dioxide. Similarly, the various carbonates, such as alkali metal carbonates, are capable of providing the requisite oxides. Care should be taken not to include substantial amounts of hydrated components if fluorides are present in the composition because of the formation of volatile fluorides.
It should be appreciated that high purity for the raw materials is not required, and the compositions in accordance with the present invention can have the ordinary small amounts of impurities encountered in ceramic practice without serious shortcomings.
For efficiency and economy the Period IV metal oxide is an iron oxide and for purposes of calculation in the batch this specification reckons the iron oxide as Fe203, although it can be charged to the batch in other form. Other Period IV metal oxides wherein the metal has Atomic Number of 23 - 28 include the oxides of cobalt, manganese, chromium, vanadium, and nickel. For the purposes of calculation herein cobalt oxide is reckoned as Co304, manganese oxide as MnO2, chromium oxide as Cr203, vanadium oxide as V205, and nickel oxide as NiO. Nickel oxide is not as potent a fluxing mater-ial as is iron oxide and is considerably more expensive. The oxides of man-ganese, chromium, and vanadium often are useful in specialty steels or in certain stainless steels, but ordinarily will be avoided in various high-quality, low-carbon steels. They have reasonable fluxing effectiveness.
Cobalt oxide also has similar effectiveness to iron oxide but is, of course, fairly expensive. These materials need not be charged as oxides to the batch but usually are. Zirconia is also a useful viscosity adjusting agent, amounts in excess of 1% tending to give increasing viscosity and lower flowidity, whereas very small fractions of 1% work oppositely.
Raw batch ingredients for the flux preferably are premixed in the dry state, then melted and cooled to form frit (i.e., small vitreous par-ticles). It should be noted that the fusion or smelting temperature for most compositions falling in the ranges specified herein will not exceed 2500F.
The resulting frit usually is crushed and pulverized to form particles in fineness passing at least 20 mesh (Tyler Standard Sieve) and advantageously being mostly between 50 and 100 mesh in size or even finer (e.g., at least 50% passing lOO mesh). Alternatively, often with advantage, the frit can be used directly from customary quenching. It has been found that the flux can be used in this particulate form in the continuous casting process by simply providing a layer on the surface of the molten metal at the top of the mold in the caster. An adequate layer of the flux usually is about 1 to 2 inches or more in thickness and is maintained in such thickness throughout the continu-ous casting process by periodic or continuous additions. Typically, the amount of the flux utili~ed is about 1 pound per ton and generally in the range of 0.2 to 1.5 pounds per ton of steel cast.
The following specific examples are given for the purpose of il-lustration and are not intended to be limiting. All parts and percentages ar0 by weight unless specified otherwise.
A flux composition was prepared by conventionally dry-mixing, fusing, and friting conventional raw batch ingredients listed below:
Raw Batch Composition Ingredient Percent by Weight CaF2 16.1 Spodumene 32.2 A1203 2.8 SrC03 Na2C3 34.2 Feldspar 5-3 100 .0 to yield frit of the following analysis:
Oxide Percent-by Weight Na20 22.0 Li20 3.0 SrO 8.1 CaO 14.8 A1203 16.0 Si02 32.1 F 10.0 106.0 The flowidity of the flux Caccording to the method discussed in ~0368Z5 United States patent 3,649,249, cited herein) was measured to be 4 inches.
Similarly the Plastic Deformation Point was about 1300F. When iron oxide is added to this fluxes, increased flowidity is obtained. On the other hand, the observed flowidity can be preserved even though refractory materials such as alumina and silica are raised somewhat in content. This flux was especial-ly useful for covering the molten metal surface of the top of a continuous casting mold while preventing attack on alumina-graphite molten metal nozzles feeding said mold.
A flux composition was prepared by conventionally dry-mixing, fus-ing, and fritting conventional raw batch ingredients listed below:
Raw Batch Composition Ingredient Percent by Ueight Na2SiF6 12.4 Na5P3010 26.8 Na2C03 7.8 Li2C3 14.5 BaC03 5 SrC03 4.1 SiO2 20.4 100 .0 to yield frit of the following analysis:
Oxide Percent by ~eight Na20 22.2 Li20 6.5 CaO 14.2 P205 17.0 SiO2 27.0 F 13.0 BaO 4.2 SrO 3 0 107.1 1036~ZS
The flowidity of the flux (according to the method described in United States patent 3,649,249, cited herein) was 9 inches. Similarly the Plastic Deformation Point was about 1050F. When iron oxide is added to this fluxes, increased flowidity is obtained. On the other hand, the observed flowidity can be preserved even though refractory materials such as alumina and silica are raised somewhat in content. This flux composition was of a lower melting range and was especially useful as a starter flux in continuous casting of steel.
A flux composition was prepared by conventionally dry-mixing, fusing, and fritting conventional raw batch ingredients listed below:
Raw Batch Composition Ingredient Percent by Weight SiO2 31.1 Na2C3 26.7 CaF2 24.6 CaC03 5.0 Li2C3 7.0 K2C03 2.6 i2 3.0 100 . O
to yield frit of the following analysis:
Oxide Percent by Weight Na20 19.7 K20 2.8 Li20 4-7 CaO 27.4 SiO2 35.8 F 9.2
The present invention relates to improvements in flux compositions for continuous casting of steel, and to such process using such flux.
Various steels such as high quality deoxidized carbon steel and certain stainless steels can be and often are now made by the process of continuous casting. In such manufacture inclusions of various materials such as oxides, silicates, and aluminates are particularly undesirable because they can give rise to surface or subsurface defects. Additionally, the mold desirably is protected at the top from attack by oxygen using a slag or flux.
Such slag or flux can help to suppress the formation of these undesirable inclusions, as well as to lubricate the steel as it is going through the mold and to affect heat transfer from the hot steel to the cooled mold.
A desirable flux composition for such continuous casting must possess chemical and thermal stability during contact with the molten steel in order to avoid generation of appreciable quantities of objectionable fumes, toxic gases, decomposition products, or by-products which might harm personnel or contaminate the product. Thus, lead-providing material in appreciable proportion is not used. Often such flux composition is called on to solubilize some of the impurities such as oxides, silicates, or aluminates which are believed to be the cause of most surface or subsurface imperfections found in continuous castings or in formed materials produced therefrom. The flux com-position should have a softening point (or a plastic deformation point) and a flowidity such that the layer of flux on the molten steel maintains its effectiveness during the casting process. Various fluxing and refractory ingredients can be tolerated in small proportions in the resulting steel in some cases; in other instances they must be low or absent to suppress transfer to the steel. Hence, aluminum-providing material in a flux is undesirable for use with some aluminum-killed steels, but can be used with the casting of other steels; various Period IV metal-providing materials can be tolerated in fluxes for steels normally containing them; occasionally boron oxide is un-desirable in fluxes for various steel.
., - 1 - ~
ib368zs Halley, in his ~nited States patent 3,649,249, discloses a synthetic slag composition e~inently suitable for use in the continuous casting of aluminum-killed steel, said slag having the composition: silica 10 to 5S%, calcia 0 to 40%, calcium fluoride 5 to 40%, sodium oxide and potassium oxide 5 to 35%, lithium oxide and lithium fluoride 0.5 to 15%, boria 0 to 30%; with the provision that the boria, calcium fluoride and lithium fluoride represent in combination, more than 15% of the composition, all percentages being by weight. Halley also characterizes his slag composition as having several particular properties: specific flowidity and plastic deformation point, both of which can be determined by standarized methods shown in the patent, and solubility of alumina therein in excess of 20%.
~xtensive testing of Halley's synthetic slag has shown it to be superior to any of the heterogeneous prior art slag (flux) compositions for suppressing the incidence of surface defects on such steels made by continuous casting; nevertheless, defects to the extent of about 10 percent often occur with such slag. Fortunately, such defects are not entirely of a serious type. However, even minor defects are undesirable because they require additional time, cost, and effort for correction.
Fluxes made in accordance with the present invention have been found quite efficient in the continuous casting of various steels. For elimin-ating defects they compare favorably with those heretofor produced. They can also be made to reduce attack on alumina-graphite molten metal inlet tubes ~shrouds) to the oQntinuous caster. Furthermore, the alumina content of the instant fluxes can be adjusted within the limits stated herein to further sup-press alumina solubility from the metal at modest sacrifice in raising fusion temperature and lowering flowidity of the flux. The instant flux compositions do not appear to form undesirable immiscible liquid phases at the elevated continuous casting temperatures.
An important distinction here from my prior work, Canadian patent applicatio~ 180,865 filed September 12, 1973, and from the Halley patent, is 10;~682S
the incorporation of an oxide of a Period IV metal having Atomic Number of 23 - 28, inclusive. Such inclusion reduces the softening point of the flux and increases flowidity, thus giving the flux desirable flowidity even though it contains refractory ingredients in appreciable proportions. Another adva~-tageous feature of the instant flux is the inclusion of a relatively small proportion of titanium dioxide. In small proportion ~less than about 4%) such inclusion tends to increase flowidity and reduce softening temperature of the flux, but as larger proportions of titanium dioxide are added up to the limits stated, viscosity of the flux is increased and this tends to reduce flowidity for controlling the balance of flowidity with the other desirable properties.
The flux composition according to the present invention is sub-stantially entirely in the vitreous state as frit particles, has flowidity and plastic deformation point suitable for use in the continuous casting of steel, and consists essentially of:
Advantageously Ingredient Broadly Wt. % Wt. %
Na20 6-25 8-23 Li20 0-8 3-7 SiO2 5-40 20-36 Mgo 0-20 0-10 CaO 5-30 8-30 BaO 0-20 0-10 SrO 0-20 0-10 Oxide of Period IV
metal having Atomic Number of 23-28, inclusive 1-10 1-6 TiO2 0-6 1-4 Zr2 0-5 0-3 1036~12S
In a process for the continuous casting of steel using an open-ended mold, the invention also provides the improvement which comprises cover-ing the exposed surface of the molten metal with a layer of such flux com-position (usually handled by scoop and maintained several inches thick).
When the foregoing compositional limitations are complied with, the flux flowidity will be in the usual range for continuous casting of steel (i.e., about 2" - 16" as measured according to United States patent 3,649,249) and advantageously about 6" - 10". Similarly the Plastic Deformation Point of the flux will be between about 1000 and about 1500 ., useful for continuous casting of steel. The alumina solubility will be at most about 15 - 17%
measured in accordance with the test shown in United States patent 3,649,249.
If the flux composition contains alumina, the alumina solubility will be diminished correspondingly.
While it is possible to use very small proportions (30% or less of the frit) of finely ground additives with the frit, which additives can smelt down in the caster to augment the composition within the limits stated, the flux as all frit appears to operate the best and most reliably in the con-tinuous casting of steel. The frit can be used as directly fritted or can be ground and classified according to desired size ranges. Usually it is cheaper to use the frit as it is fritted by quenching from a smelter operation.
The flux compositions can be smelted from actual oxides or pre-ferably for economy from their conventional ceramic raw material equivalents.
For example, some raw materials can be used to provide one or more ingredients of the flux such as sodium silicate which can provide sodium oxide as well as silicon dioxide. Similarly, the various carbonates, such as alkali metal carbonates, are capable of providing the requisite oxides. Care should be taken not to include substantial amounts of hydrated components if fluorides are present in the composition because of the formation of volatile fluorides.
It should be appreciated that high purity for the raw materials is not required, and the compositions in accordance with the present invention can have the ordinary small amounts of impurities encountered in ceramic practice without serious shortcomings.
For efficiency and economy the Period IV metal oxide is an iron oxide and for purposes of calculation in the batch this specification reckons the iron oxide as Fe203, although it can be charged to the batch in other form. Other Period IV metal oxides wherein the metal has Atomic Number of 23 - 28 include the oxides of cobalt, manganese, chromium, vanadium, and nickel. For the purposes of calculation herein cobalt oxide is reckoned as Co304, manganese oxide as MnO2, chromium oxide as Cr203, vanadium oxide as V205, and nickel oxide as NiO. Nickel oxide is not as potent a fluxing mater-ial as is iron oxide and is considerably more expensive. The oxides of man-ganese, chromium, and vanadium often are useful in specialty steels or in certain stainless steels, but ordinarily will be avoided in various high-quality, low-carbon steels. They have reasonable fluxing effectiveness.
Cobalt oxide also has similar effectiveness to iron oxide but is, of course, fairly expensive. These materials need not be charged as oxides to the batch but usually are. Zirconia is also a useful viscosity adjusting agent, amounts in excess of 1% tending to give increasing viscosity and lower flowidity, whereas very small fractions of 1% work oppositely.
Raw batch ingredients for the flux preferably are premixed in the dry state, then melted and cooled to form frit (i.e., small vitreous par-ticles). It should be noted that the fusion or smelting temperature for most compositions falling in the ranges specified herein will not exceed 2500F.
The resulting frit usually is crushed and pulverized to form particles in fineness passing at least 20 mesh (Tyler Standard Sieve) and advantageously being mostly between 50 and 100 mesh in size or even finer (e.g., at least 50% passing lOO mesh). Alternatively, often with advantage, the frit can be used directly from customary quenching. It has been found that the flux can be used in this particulate form in the continuous casting process by simply providing a layer on the surface of the molten metal at the top of the mold in the caster. An adequate layer of the flux usually is about 1 to 2 inches or more in thickness and is maintained in such thickness throughout the continu-ous casting process by periodic or continuous additions. Typically, the amount of the flux utili~ed is about 1 pound per ton and generally in the range of 0.2 to 1.5 pounds per ton of steel cast.
The following specific examples are given for the purpose of il-lustration and are not intended to be limiting. All parts and percentages ar0 by weight unless specified otherwise.
A flux composition was prepared by conventionally dry-mixing, fusing, and friting conventional raw batch ingredients listed below:
Raw Batch Composition Ingredient Percent by Weight CaF2 16.1 Spodumene 32.2 A1203 2.8 SrC03 Na2C3 34.2 Feldspar 5-3 100 .0 to yield frit of the following analysis:
Oxide Percent-by Weight Na20 22.0 Li20 3.0 SrO 8.1 CaO 14.8 A1203 16.0 Si02 32.1 F 10.0 106.0 The flowidity of the flux Caccording to the method discussed in ~0368Z5 United States patent 3,649,249, cited herein) was measured to be 4 inches.
Similarly the Plastic Deformation Point was about 1300F. When iron oxide is added to this fluxes, increased flowidity is obtained. On the other hand, the observed flowidity can be preserved even though refractory materials such as alumina and silica are raised somewhat in content. This flux was especial-ly useful for covering the molten metal surface of the top of a continuous casting mold while preventing attack on alumina-graphite molten metal nozzles feeding said mold.
A flux composition was prepared by conventionally dry-mixing, fus-ing, and fritting conventional raw batch ingredients listed below:
Raw Batch Composition Ingredient Percent by Ueight Na2SiF6 12.4 Na5P3010 26.8 Na2C03 7.8 Li2C3 14.5 BaC03 5 SrC03 4.1 SiO2 20.4 100 .0 to yield frit of the following analysis:
Oxide Percent by ~eight Na20 22.2 Li20 6.5 CaO 14.2 P205 17.0 SiO2 27.0 F 13.0 BaO 4.2 SrO 3 0 107.1 1036~ZS
The flowidity of the flux (according to the method described in United States patent 3,649,249, cited herein) was 9 inches. Similarly the Plastic Deformation Point was about 1050F. When iron oxide is added to this fluxes, increased flowidity is obtained. On the other hand, the observed flowidity can be preserved even though refractory materials such as alumina and silica are raised somewhat in content. This flux composition was of a lower melting range and was especially useful as a starter flux in continuous casting of steel.
A flux composition was prepared by conventionally dry-mixing, fusing, and fritting conventional raw batch ingredients listed below:
Raw Batch Composition Ingredient Percent by Weight SiO2 31.1 Na2C3 26.7 CaF2 24.6 CaC03 5.0 Li2C3 7.0 K2C03 2.6 i2 3.0 100 . O
to yield frit of the following analysis:
Oxide Percent by Weight Na20 19.7 K20 2.8 Li20 4-7 CaO 27.4 SiO2 35.8 F 9.2
2 3.0 102.6 The flowdity of this flux ~according to the method disclosed in -United States patent 3J649J249, cited herein) was measured to be 6 inches.
Similarly the Plastic Deformation Point was about 1150F. When iron oxide is added to this fluxes, increased flowidity is obtained. On the other hand, the observed flowidity can be preserved even though refractory materials such as alumina and silica are raised somewhat in content. The Ti02 was a valuable additive to reduce the softening range of the flux for use in continuous casting of steel. In other like fluxes the titanium dioxide content was varied from 1.2-5.6 parts, but the 3% level of Ti02 gave the lowest softening range of such fluxes.
A flux composition was prepared by conventionally dry-mixing, fusing, and fritting conventional raw batch ingredients listed below:
Raw Batch ComPOSitiOn Ingredient Percent by Weight CaF2 22.1 Na2B4O7 5-5 Na2C3 13.0 Si02 14.1 Spodumene 26.7 NaF 8.7 Li2C3 4.8 Fe 0 5.1 2 3 100.0 to yield frit of the following analysis:
Oxide Percent by Weight Li2O 4.0 Na2O 16.4 CaO 16.3 2 3 4.0 Si02 32.8 F 15.0 Fe 0 2 3 101.2 _ g _ 1036~25 The flowidity of the flux (according to the method disclosed in United States patent 3,649,249, cited herein) was measured to be 5 inches.
Similarly the Plastic Deformation Point was about 1200F. The iron oxide was found to impart excellent flowidity in spite of the alumina content.
A flux composition was prepared by conventionally dry-mixing, fusing, and fritting conventional raw batch ingredients listed below:
Raw Batch Composition Ingredient Percent by Weight CaF2 31.7 Na2B407 5.8 Na2C3 10.8 Spodumene 42.4 Feldspar 2.3 Al203 1.8 Fe 0 5.2 2 3 100.0 to yield frit of the following analysis:
Oxide Percent by Wei~ht Li20 3.0 Na20 8.4 CaO 22.3 2 3 4.0 A123 13.4 SiO2 28.8 F 15.0 Fe 0 5.2 2 3 loo.l The flowidity of the flux ~according to the method disclosed in United States patent 3,649,249, cited herein) was measured to be 3 inches.
Similarly the Plastic Deformation Point was about 1500~F. The combination of iron oxide and aluminum oxide was used to generate special hardness with 10;~6~ZS
reasonable flow. In this specification the flowidity tests were performed at 2600F.
A series of flux compositions was prepared by the same conven-tional dry mixing described earlier, followed by fusing, and fritting the conventional raw batch ingredients to yield fluxes having the following tabulated analyses and properties:
ExamPle 6ExamPle 7Example 8 Example 9 ''EXample'10 Li20 2.1 2.1 2.1 2.1 2.1 Na20 22.0 22.0 22.0 22.0 22.0 CaO 25.0 25.0 25.0 25.0 25.0 SiO2 31.0 31.0 31.0 31.0 31.8 MgO 3.0 3.0 3.0 3.0 3.0 BaO 3.0 3.0 3.0 3.0 3.0 Fe203 3.0 3.0 3.0 3.0 3.0 Cr203 75 MnO2 - .75 NiO - - .75 CoO - - - .75 F 10.1 10.1 10.1 10.1 10.1 Herty Plow 6" 6-1/4" 6" 6" 5-1/2"
PDP* 1200F. 1150F. 1200F. 1200F. 1300~F.
*Plastic Deformation Point Examples 6 through 9 illustrate that Cr203, MnO2, NiO, and CoO
all have similar properties in these casting fluxes reducing the Plastic Deformation Point and increasing the Flowidity over Example 10 containing none of these metal oxides. Iron oxide which also has a similar effect was main-tained constant. The flux from Example 6 was made in one-ton quantity and us-ed experimentally for continuous casting of a 1010 type steel on a 7" square billet caster with good operating results and good surfaces on the cast billet.
Similarly the Plastic Deformation Point was about 1150F. When iron oxide is added to this fluxes, increased flowidity is obtained. On the other hand, the observed flowidity can be preserved even though refractory materials such as alumina and silica are raised somewhat in content. The Ti02 was a valuable additive to reduce the softening range of the flux for use in continuous casting of steel. In other like fluxes the titanium dioxide content was varied from 1.2-5.6 parts, but the 3% level of Ti02 gave the lowest softening range of such fluxes.
A flux composition was prepared by conventionally dry-mixing, fusing, and fritting conventional raw batch ingredients listed below:
Raw Batch ComPOSitiOn Ingredient Percent by Weight CaF2 22.1 Na2B4O7 5-5 Na2C3 13.0 Si02 14.1 Spodumene 26.7 NaF 8.7 Li2C3 4.8 Fe 0 5.1 2 3 100.0 to yield frit of the following analysis:
Oxide Percent by Weight Li2O 4.0 Na2O 16.4 CaO 16.3 2 3 4.0 Si02 32.8 F 15.0 Fe 0 2 3 101.2 _ g _ 1036~25 The flowidity of the flux (according to the method disclosed in United States patent 3,649,249, cited herein) was measured to be 5 inches.
Similarly the Plastic Deformation Point was about 1200F. The iron oxide was found to impart excellent flowidity in spite of the alumina content.
A flux composition was prepared by conventionally dry-mixing, fusing, and fritting conventional raw batch ingredients listed below:
Raw Batch Composition Ingredient Percent by Weight CaF2 31.7 Na2B407 5.8 Na2C3 10.8 Spodumene 42.4 Feldspar 2.3 Al203 1.8 Fe 0 5.2 2 3 100.0 to yield frit of the following analysis:
Oxide Percent by Wei~ht Li20 3.0 Na20 8.4 CaO 22.3 2 3 4.0 A123 13.4 SiO2 28.8 F 15.0 Fe 0 5.2 2 3 loo.l The flowidity of the flux ~according to the method disclosed in United States patent 3,649,249, cited herein) was measured to be 3 inches.
Similarly the Plastic Deformation Point was about 1500~F. The combination of iron oxide and aluminum oxide was used to generate special hardness with 10;~6~ZS
reasonable flow. In this specification the flowidity tests were performed at 2600F.
A series of flux compositions was prepared by the same conven-tional dry mixing described earlier, followed by fusing, and fritting the conventional raw batch ingredients to yield fluxes having the following tabulated analyses and properties:
ExamPle 6ExamPle 7Example 8 Example 9 ''EXample'10 Li20 2.1 2.1 2.1 2.1 2.1 Na20 22.0 22.0 22.0 22.0 22.0 CaO 25.0 25.0 25.0 25.0 25.0 SiO2 31.0 31.0 31.0 31.0 31.8 MgO 3.0 3.0 3.0 3.0 3.0 BaO 3.0 3.0 3.0 3.0 3.0 Fe203 3.0 3.0 3.0 3.0 3.0 Cr203 75 MnO2 - .75 NiO - - .75 CoO - - - .75 F 10.1 10.1 10.1 10.1 10.1 Herty Plow 6" 6-1/4" 6" 6" 5-1/2"
PDP* 1200F. 1150F. 1200F. 1200F. 1300~F.
*Plastic Deformation Point Examples 6 through 9 illustrate that Cr203, MnO2, NiO, and CoO
all have similar properties in these casting fluxes reducing the Plastic Deformation Point and increasing the Flowidity over Example 10 containing none of these metal oxides. Iron oxide which also has a similar effect was main-tained constant. The flux from Example 6 was made in one-ton quantity and us-ed experimentally for continuous casting of a 1010 type steel on a 7" square billet caster with good operating results and good surfaces on the cast billet.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A flux composition having flowidity and plastic deformation point suitable for use in the continuous casting of steel, said composition being substantially entirely in the vitreous state as frit particles, and consisting essentially of:
2. The flux composition according to claim 1 consisting essentially of
3. The flux composition according to claim 1 wherein the oxide of said Period IV metal is an iron oxide.
4. The flux composition according to claim 2 wherein the oxide of said Period IV metal is Fe203.
5. In a process for the continuous casting of steel using an open-ended mold for the molten metal, the improvement which comprises covering the exposed surface of said molten metal with a layer of the flux composition of claim 1 or 2.
6. In a process for the continuous casting of steel using an open-ended mold for the molten metal, the improvement which comprises covering the exposed surface of said molten metal with a layer of the flux composition of claim 3 or 4.
7. The flux composition according to claim 1 wherein the oxide of said Period IV metal is a mixture of iron oxide and an oxide selected from Cr2O3, MnO2, Nio and CoO.
8. The flux composition according to claim 2 wherein the oxide of said Period IV metal is a mixture of iron oxide and an oxide selected from Cr2O3, MnO2, NiO and CoO.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA232,685A CA1036825A (en) | 1975-08-01 | 1975-08-01 | Flux for continuous casting of steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA232,685A CA1036825A (en) | 1975-08-01 | 1975-08-01 | Flux for continuous casting of steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1036825A true CA1036825A (en) | 1978-08-22 |
Family
ID=4103755
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA232,685A Expired CA1036825A (en) | 1975-08-01 | 1975-08-01 | Flux for continuous casting of steel |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1036825A (en) |
-
1975
- 1975-08-01 CA CA232,685A patent/CA1036825A/en not_active Expired
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