US20010010181A1 - Method and system for producing steel having low nitrogen content - Google Patents
Method and system for producing steel having low nitrogen content Download PDFInfo
- Publication number
- US20010010181A1 US20010010181A1 US09/817,941 US81794101A US2001010181A1 US 20010010181 A1 US20010010181 A1 US 20010010181A1 US 81794101 A US81794101 A US 81794101A US 2001010181 A1 US2001010181 A1 US 2001010181A1
- Authority
- US
- United States
- Prior art keywords
- molten metal
- flux
- denitrogenizing
- introducing
- silicates
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 30
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title description 42
- 229910000831 Steel Inorganic materials 0.000 title description 37
- 239000010959 steel Substances 0.000 title description 37
- 229910052757 nitrogen Inorganic materials 0.000 title description 21
- 230000004907 flux Effects 0.000 claims abstract description 75
- 229910052751 metal Inorganic materials 0.000 claims abstract description 67
- 239000002184 metal Substances 0.000 claims abstract description 67
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 12
- 239000011575 calcium Substances 0.000 claims description 12
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims description 12
- 239000011777 magnesium Substances 0.000 claims description 12
- 150000004760 silicates Chemical class 0.000 claims description 12
- 239000010936 titanium Substances 0.000 claims description 12
- 229910052782 aluminium Inorganic materials 0.000 claims description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 9
- 239000007769 metal material Substances 0.000 claims description 8
- 150000001875 compounds Chemical class 0.000 claims description 7
- 150000002739 metals Chemical class 0.000 claims description 7
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 6
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 6
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 6
- 239000003513 alkali Substances 0.000 claims description 6
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 6
- 229910052788 barium Inorganic materials 0.000 claims description 6
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 6
- 229910052796 boron Inorganic materials 0.000 claims description 6
- 229910052791 calcium Inorganic materials 0.000 claims description 6
- 229910052749 magnesium Inorganic materials 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- 238000005253 cladding Methods 0.000 claims description 3
- 230000003466 anti-cipated effect Effects 0.000 claims description 2
- 230000001737 promoting effect Effects 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims description 2
- 150000002222 fluorine compounds Chemical class 0.000 claims 4
- 239000002893 slag Substances 0.000 abstract description 22
- 239000000463 material Substances 0.000 abstract description 16
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 239000007788 liquid Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 229910001338 liquidmetal Inorganic materials 0.000 description 3
- 150000004767 nitrides Chemical class 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 238000009628 steelmaking Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- ULSFLOAZQDMJLA-UHFFFAOYSA-N [Ca].[B]=O Chemical group [Ca].[B]=O ULSFLOAZQDMJLA-UHFFFAOYSA-N 0.000 description 2
- 150000004673 fluoride salts Chemical class 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 229910004261 CaF 2 Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 230000003009 desulfurizing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- -1 steel Chemical class 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
- 238000009849 vacuum degassing Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Images
Classifications
-
- 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
- C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
-
- 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
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D3/00—Charging; Discharging; Manipulation of charge
- F27D3/0025—Charging or loading melting furnaces with material in the solid state
- F27D3/0026—Introducing additives into the melt
Definitions
- This invention relates in general to the field of metallurgical processing, and more specifically to processes for adding materials, such as fluxes, into molten metal such as liquid steel.
- nitrogen is generally considered to be an unwanted element in steel.
- Nitrogen enters into liquid steel from the air and from contaminants, such as oil, that may find their way into the raw and recycled material from which steel is made.
- the nitrogen changes the mechanical properties of steel, making it harder and less ductile. It can also chemically combine with aluminum, or other elements, to form inclusions, affecting the quality of the product.
- Combined compounds can also migrate to grain boundaries in the steel's microstructure, weakening the steel at elevated temperatures, giving rise to inter-granular cracks.
- Nitrogen levels are particularly a problem in steel that is produced by the so-called “mini-mills,” which generally use electric arc furnaces to melt the steel and that also tend to use a relatively high level of metal scrap as source material. It is not uncommon to see steels that are produced at such facilities as having a nitrogen content that is within the range of about 60 parts per million (ppm) to about 120 ppm. Steels that are made in mills having a basic oxygen furnace, on the other hand, have a nitrogen content that is commonly within the range of about 30 ppm to about 50 ppm. Some specialty applications, such as for the automotive body, however, require nitrogen levels that are as low as 20 ppm.
- the top ladle slag denitrogenizing treatment would require skimming of carried over furnace slag from the ladle and introduction of a synthetic denitrogenizing ladle flux of a specific composition on top of liquid steel. Adding of such flux to the ladle already containing other slag would not be desired and effective due to the dilution effect by the other slag. Effects of nitrogen removal by doing so would be questionable due to variability of composition of diluted ladle slag.
- the skimming operations which are not uncommon in some practices such as special desulfurization processes, are very time consuming and not energy efficient. Temperature loss of steel in the ladle not covered with slag can amount to 100-150 degrees F depending on the type of operation. Addition of solid slag fluxing mix requires extended heating to melt and bring the mix into solution. This requires a great deal of time and energy, both of which are expensive factors in the overall cost of production.
- a method of introducing a denitrogenizing flux to an amount of molten metal includes, according to a first aspect of the invention steps of: (a) encasing the denitrogenizing flux with an outer layer of a metallic material of equal of lower melting point in comparison to the liquid metal; and (b) introducing the flux so encased into the molten metal, whereby the outer layer will melt, thereby introducing the flux into the molten metal.
- an article for introducing a denitrogenizing flux to an amount of molten metal includes an outer layer of a metallic material that has a melting point that is beneath the anticipated temperature of the amount of molten metal; and a denitrogenizing flux that is encased within the molten metal, whereby the outer layer will melt after the article has been introduced into the molten metal for a predetermined period of time, thereby permitting introduction of the denitrogenizing flux into the molten metal at a depth below the top surface of the molten metal.
- a method of denitrogenizing an amount of molten metal includes steps of: (a) providing an amount of molten metal; and (b) introducing a denitrogenizing flux into the molten metal in such a way that the flux becomes exposed to the molten metal at a location that is at a depth that is substantially below the top surface of the molten metal, thereby promoting more efficient mixing of the flux into the molten metal.
- a method of introducing a denitrogenizing flux to an amount of molten metal includes, according to a fourth aspect of the invention, steps of: (a) supplying an amount of denitrogenizing flux into a lance assembly of the type that includes a nozzle that is constructed and arranged to be immersed in molten metal; and (b) using the lance assembly to introduce the flux into the molten metal.
- FIG. 1 is a schematic depiction of a conventional wire feed machine, which is shown in operation according to the invention
- FIG. 2 is a cross-sectional view taken along lines 2 - 2 in FIG. 1;
- FIG. 3 is a schematic depiction of a system constructed according to an alternative embodiment of the invention.
- FIG. 4 is a schematic control diagram.
- an improved system 10 for producing steel that has a low nitrogen content includes a source 12 of a wire vector 14 that is constructed and arranged to introduce a denitrogenizing flux into molten metal such as steel.
- System 10 utilizes a conventional wire feed machine of the type that includes feeding structure 16 for feeding the wire vector into a guide chute 18 at a controlled velocity so as to cause the wire vector 14 to penetrate into the molten steel 22 at a predetermined speed and direction.
- Wire vector 14 further includes an inner body of a powdered denitrogenizing flux material 26 , which includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).
- the most preferred flux materials are CaO—BaO—TiO 2 —(Al 2 O 3 ), CaO—TiO 2 (Al 2 O 3 ) and Calcium-Boron oxide bearing fluxes.
- any other flux that is capable of achieving the desired denitrogenization could be substituted.
- a process according to one embodiment of the invention involves encasing the denitrogenizing flux 26 with the outer layer of metallic material 24 and introducing the flux 26 so encased into the molten metal 22 , whereby the outer layer will melt, thereby introducing the flux into the molten metal.
- a system 30 for introducing a denitrogenizing flux 20 to an amount of molten metal 32 that is constructed according to a preferred embodiment of the invention includes a container 34 , such as a ladle, for holding an amount of molten metal 32 such as liquefied steel.
- System 30 further includes a lance assembly 36 that is preferably inclusive of a container or hopper 38 of a supply of denitrogenizing flux 40 , and a lance 42 for introducing the flux 40 into the molten metal 32 .
- the flux material 40 is a powdered denitrogenizing flux material which includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).
- the most preferred flux materials are CaO—BaO—TiO 2 —(Al 2 O 3 ), CaO—TiO 2 —(Al 2 O 3 ) and Calcium-Boron oxide bearing fluxes.
- any other flux that is capable of achieving the desired denitrogenization could be substituted.
- a second end of the lance 42 terminates in a nozzle 48 , which during operation of the system 30 is immersed in the molten metal 32 .
- the portion of the lance 42 that is expected to be immersed in the molten metal 32 during operation is encased in a protective refractory sleeve 54 , as is shown in FIG. 3.
- a conveyor 50 that is powered by a motor 52 is positioned to supply flux material from the hopper 38 into the lance 42 at a location that is between the valve 46 and the nozzle 48 .
- System 30 includes a control system having a CPU 56 that controls operation of the motor 52 and the valve 56 .
- system 30 is operated to introduce the denitrogenizing flux 40 into the molten metal 32 by CPU 56 instructing motor 52 to cause conveyor 50 to move flux into the lance 42 , and by opening valve 46 , thus causing the flux 40 to become entrained in the flow of inert gas that is provided by the pressure source 44 .
- the flux is then injected into the molten metal 32 at a preselected depth and velocity that is chosen to promote fast, efficient mixing of the flux 40 with the molten metal 32 .
- the invention adds denitrogenizing flux in a manner that is less time consuming and less wasteful of energy than methods of flux addition and mixing that are in conventional use.
Abstract
A method of introducing a denitrogenizing flux material into a container of molten metal includes steps of providing a wire-like vector that has an inner core of flux material and an outer layer that is used to contain the inner core, and using a wire feed machine to introduce the wire-like vector into a container of molten metal. In comparison with conventional top slag removal techniques, this process permits the material from which the inner core is made to be injected into the container of molten metal at a speed and direction that promotes a controlled mixing of the flux material and the molten metal.
Description
- This is a continuation-in-part of Ser. No. 08/866,173, filed May 30, 1997 and a continuation-in-part of Ser. No. 08/979,771, filed Nov. 26, 1997, the disclosures of which are hereby incorporated by reference as if fully set forth herein.
- 1. Field of the Invention
- This invention relates in general to the field of metallurgical processing, and more specifically to processes for adding materials, such as fluxes, into molten metal such as liquid steel.
- 2. Description of the Prior Art
- In the production of metals such as steel, it is sometimes desirable to remove unwanted trace elements from the liquid metal by reacting one or more flux materials with the liquid metal.
- For example, nitrogen is generally considered to be an unwanted element in steel. Nitrogen enters into liquid steel from the air and from contaminants, such as oil, that may find their way into the raw and recycled material from which steel is made. The nitrogen changes the mechanical properties of steel, making it harder and less ductile. It can also chemically combine with aluminum, or other elements, to form inclusions, affecting the quality of the product. Combined compounds can also migrate to grain boundaries in the steel's microstructure, weakening the steel at elevated temperatures, giving rise to inter-granular cracks.
- Nitrogen levels are particularly a problem in steel that is produced by the so-called “mini-mills,” which generally use electric arc furnaces to melt the steel and that also tend to use a relatively high level of metal scrap as source material. It is not uncommon to see steels that are produced at such facilities as having a nitrogen content that is within the range of about 60 parts per million (ppm) to about 120 ppm. Steels that are made in mills having a basic oxygen furnace, on the other hand, have a nitrogen content that is commonly within the range of about 30 ppm to about 50 ppm. Some specialty applications, such as for the automotive body, however, require nitrogen levels that are as low as 20 ppm. Some facilities use vacuum degassing equipment, which essentially exposes the liquid steel to near vacuum conditions to decarburize the steel. Some degree of nitrogen removal may be achieved as a by-product of this process. Unfortunately, this process is expensive and is not able to extract nitrogen that has already chemically combined with other elements, such as aluminum.
- More recently, it has been proposed to use fluxes to remove nitrogen from molten steel by adding a synthetic ladle slag of appropriate composition to the top surface of the molten steel within a ladle. The top slag process, which is also in common practice for desulfurizing steel, involves heating the steel within the ladle for an extended period of time and to circulate the steel, thereby exposing all the molten metal over time to the liquid metal-slag reaction interface. While denitrogenization with top ladle slag is promising in the sense that it permits reduction of nitrogen to levels otherwise not achievable by other processes, it has several practical limitations and consequently it is not in wide practice at this point. The top ladle slag denitrogenizing treatment would require skimming of carried over furnace slag from the ladle and introduction of a synthetic denitrogenizing ladle flux of a specific composition on top of liquid steel. Adding of such flux to the ladle already containing other slag would not be desired and effective due to the dilution effect by the other slag. Effects of nitrogen removal by doing so would be questionable due to variability of composition of diluted ladle slag. The skimming operations, which are not uncommon in some practices such as special desulfurization processes, are very time consuming and not energy efficient. Temperature loss of steel in the ladle not covered with slag can amount to 100-150 degrees F depending on the type of operation. Addition of solid slag fluxing mix requires extended heating to melt and bring the mix into solution. This requires a great deal of time and energy, both of which are expensive factors in the overall cost of production.
- Denitrogenization using fluxes is being explored in several universities on experimental scale. The removal of nitrogen from steel appears to take place both in acidic and basic fluxes. The nitride capacity of fluxes has a V-shaped dependency on the optical basicity. The nitride capacity is high at low optical basicity; as the optical basicity is increased it reaches a minimum and starts to increase later. This behavior is explained by Sommerville et. al. to be related to the structural effects; the nitrogen which substitutes for oxygens in the network shows an inverse relationship with basicity whereas that replacing “free” oxygens is directly related to basicity. While the knowledge of denitrogenization with fluxes is improving, the techniques used in these studies are on a laboratory scale and have employed the top slag method. As discussed above this technique has several practical limitations for routine technical uses.
- Articles addressing flux denitrogenization, the details of which are incorporated into this document as if set forth fully herein, are as follows:Studies on Slags for Nitrogen Removal from Steel, J. P. Ferreira et al., [75th Steelmaking Conference, Iron &Steel Society, Apr. 5-8, 1992, Toronto, Ontario, Canada—Abstracts], pp. 216-217; Studies of Nitrogen in Steel in a Plasma Induction Reactor with a BaO—TiO 2 Slag, L. B. McFeaters et al., [75th Steelmaking Conference, Iron &Steel Society, Apr. 5-8, 1992, Toronto, Ontario, Canada—Abstracts], pp. 218-219; and The Behavior of Nitrogen During Plasma-Enhanced Refining, M. Takahashi et al., [75th Steelmaking Conference, Iron Steel Society, Apr. 5-8, 1992, Toronto, Ontario, Canada—Abstracts], pp. 220-221; and Synthetic Slags for Nitrogen Removal, J. P. Ferreira, I. D. Sommerville, and a. Mclean, [Iron and Steelmaker, May 1992], pp. 43-49; and The use and Misuse of Capacities in Slags, I. D. Sommerville, A. Mclean and Y. D. Young [Proceedings International Conference on Molten Slags, Fluxes and Salts, 1997 Conference], pp. 375-383; and Solubility of Nitrogen in Cao—Sio 2 —CaF 2 Slag Systems, H. S. Song, D. S. Kim, D. J. Min and P. C. Rhee [Proceedings International Conference on Molten Slags, Fluxes and Salts, 1997 Conference], pp. 583-587; and Nitride Capacities in Slags, H. Suito, K. Tomioka, and J. Tanabe, [Proceedings of 4th International Conference on Molten Slags and Fluxes, 1992, Sendai], pp. 161-166.
- A need exists for an improved system and process for introducing a denitrogenizing flux to a quantity of molten metal, such as steel, in a manner that is less time consuming and less wasteful of energy than methods of flux addition and mixing that are in conventional use.
- Accordingly, it is an object of the invention to provide an improved system and process for introducing a denitrogenizing flux to a quantity of molten metal, such as steel, in a manner that is less time consuming and less wasteful of energy than methods of flux addition and mixing that are in conventional use. In order to achieve the above and other objects of the invention, a method of introducing a denitrogenizing flux to an amount of molten metal, includes, according to a first aspect of the invention steps of: (a) encasing the denitrogenizing flux with an outer layer of a metallic material of equal of lower melting point in comparison to the liquid metal; and (b) introducing the flux so encased into the molten metal, whereby the outer layer will melt, thereby introducing the flux into the molten metal.
- According to a second aspect of the invention, an article for introducing a denitrogenizing flux to an amount of molten metal includes an outer layer of a metallic material that has a melting point that is beneath the anticipated temperature of the amount of molten metal; and a denitrogenizing flux that is encased within the molten metal, whereby the outer layer will melt after the article has been introduced into the molten metal for a predetermined period of time, thereby permitting introduction of the denitrogenizing flux into the molten metal at a depth below the top surface of the molten metal. According to a third aspect of the invention, a method of denitrogenizing an amount of molten metal includes steps of: (a) providing an amount of molten metal; and (b) introducing a denitrogenizing flux into the molten metal in such a way that the flux becomes exposed to the molten metal at a location that is at a depth that is substantially below the top surface of the molten metal, thereby promoting more efficient mixing of the flux into the molten metal.
- A method of introducing a denitrogenizing flux to an amount of molten metal, includes, according to a fourth aspect of the invention, steps of: (a) supplying an amount of denitrogenizing flux into a lance assembly of the type that includes a nozzle that is constructed and arranged to be immersed in molten metal; and (b) using the lance assembly to introduce the flux into the molten metal.
- These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.
- FIG. 1 is a schematic depiction of a conventional wire feed machine, which is shown in operation according to the invention;
- FIG. 2 is a cross-sectional view taken along lines2-2 in FIG. 1;
- FIG. 3 is a schematic depiction of a system constructed according to an alternative embodiment of the invention; and
- FIG. 4 is a schematic control diagram.
- Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views, and referring in particular to FIG. 1, an improved
system 10 for producing steel that has a low nitrogen content includes asource 12 of awire vector 14 that is constructed and arranged to introduce a denitrogenizing flux into molten metal such as steel.System 10 utilizes a conventional wire feed machine of the type that includes feedingstructure 16 for feeding the wire vector into aguide chute 18 at a controlled velocity so as to cause thewire vector 14 to penetrate into themolten steel 22 at a predetermined speed and direction. - As may be seen in FIG. 2, the
wire vector 14 includes anouter layer 24 of a material, such as steel, that has a melting point that is at or beneath the temperature of themolten metal 22. Preferably, theouter layer 24 is fabricated from steel a material with equal or lower melting point than the liquid melt, preferably the outer layer can be made of steel or aluminum.Outer layer 24 thus encases the nonmetallic substance in an elongated, tube-like hollow cladding of metallic material that is designed to melt after being introduced into themolten metal 22. -
Wire vector 14 further includes an inner body of a powdereddenitrogenizing flux material 26, which includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al). The most preferred flux materials are CaO—BaO—TiO2—(Al2O3), CaO—TiO2(Al2O3) and Calcium-Boron oxide bearing fluxes. Alternatively, any other flux that is capable of achieving the desired denitrogenization could be substituted. - A process according to one embodiment of the invention involves encasing the
denitrogenizing flux 26 with the outer layer ofmetallic material 24 and introducing theflux 26 so encased into themolten metal 22, whereby the outer layer will melt, thereby introducing the flux into the molten metal. - Another embodiment of the invention is depicted in FIGS. 3 and 4. Referring in particular to FIG. 3, a
system 30 for introducing adenitrogenizing flux 20 to an amount ofmolten metal 32 that is constructed according to a preferred embodiment of the invention includes acontainer 34, such as a ladle, for holding an amount ofmolten metal 32 such as liquefied steel.System 30 further includes alance assembly 36 that is preferably inclusive of a container orhopper 38 of a supply ofdenitrogenizing flux 40, and alance 42 for introducing theflux 40 into themolten metal 32. - Preferably, the
flux material 40 is a powdered denitrogenizing flux material which includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al). The most preferred flux materials are CaO—BaO—TiO2—(Al2O3), CaO—TiO2—(Al2O3) and Calcium-Boron oxide bearing fluxes. Alternatively, any other flux that is capable of achieving the desired denitrogenization could be substituted. - A
pressure source 44 of an inert gas, preferably argon, is communicated with a first end of thelance 42, and acontrol valve 46 is interposed between thepressure source 44 and thelance 42 in order to control the flow of the inert gas through thelance 42. A second end of thelance 42 terminates in anozzle 48, which during operation of thesystem 30 is immersed in themolten metal 32. The portion of thelance 42 that is expected to be immersed in themolten metal 32 during operation is encased in a protectiverefractory sleeve 54, as is shown in FIG. 3. - A
conveyor 50 that is powered by amotor 52 is positioned to supply flux material from thehopper 38 into thelance 42 at a location that is between thevalve 46 and thenozzle 48. As may be seen in FIG. 4,System 30 includes a control system having aCPU 56 that controls operation of themotor 52 and thevalve 56. - In operation,
system 30 is operated to introduce thedenitrogenizing flux 40 into themolten metal 32 byCPU 56 instructingmotor 52 to causeconveyor 50 to move flux into thelance 42, and by openingvalve 46, thus causing theflux 40 to become entrained in the flow of inert gas that is provided by thepressure source 44. The flux is then injected into themolten metal 32 at a preselected depth and velocity that is chosen to promote fast, efficient mixing of theflux 40 with themolten metal 32. Accordingly, the invention adds denitrogenizing flux in a manner that is less time consuming and less wasteful of energy than methods of flux addition and mixing that are in conventional use. - It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Claims (11)
1. A method of introducing a denitrogenizing flux to an amount of molten metal, comprising steps of:
(a) encasing the denitrogenizing flux with an outer layer of a metallic material that has a melting point that is beneath the temperature of the amount of molten metal; and
(b) introducing the flux so encased into the molten metal, whereby the outer layer will melt, thereby introducing the flux into the molten metal.
2. A method according to , wherein step (a) is performed by encasing the flux in an elongated, tube-like hollow cladding of metallic material, thereby forming a wire-like vector.
claim 1
3. A method according to , wherein step (b) is performed by introducing the wire-like vector into the molten metal by using a conventional wire feeding machine.
claim 2
4. A method according to , wherein said denitrogenizing flux includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).
claim 1
5. An article for introducing a denitrogenizing flux to an amount of molten metal, comprising:
an outer layer of a metallic material that has a melting point that is beneath the anticipated temperature of the amount of molten metal; and
a denitrogenizing flux that is encased within the molten metal, whereby the outer layer will melt after the article has been introduced into the molten metal for a predetermined period of time, thereby permitting introduction of the denitrogenizing flux into the molten metal at a depth below the top surface of the molten metal.
6. An article according to , wherein said outer layer encases the nonmetallic substance in an elongated, tube-like hollow cladding of metallic material, thereby forming a wire-like vector.
claim 5
7. An article according to , wherein said denitrogenizing flux includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).
claim 5
8. A method of denitrogenizing an amount of molten metal, comprising steps of:
(a) providing an amount of molten metal; and
(b) introducing a denitrogenizing flux into the molten metal in such a way that the flux becomes exposed to the molten metal at a location that is at a depth that is substantially below the top surface of the molten metal, thereby promoting more efficient mixing of the flux into the molten metal.
9. A method according to , wherein said denitrogenizing flux includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).
claim 8
10. A method of introducing a denitrogenizing flux to an amount of molten metal, comprising steps of:
(a) supplying an amount of denitrogenizing flux into a lance assembly of the type that includes a nozzle that is constructed and arranged to be immersed in molten metal; and
(b) using the lance assembly to introduce the flux into the molten metal.
11. A method according to , wherein said denitrogenizing flux includes calcium oxide (CaO) and at least one compound selected from the group consisting of oxides, silicates, carbonates of alkali and alkaline earth metals and oxides, fluorides, silicates and carbonates of metals selected from the group consisting of Calcium (Ca), Silicon (Si), Magnesium (Mg), Boron (B), Titanium (Ti), Barium (Ba) and Aluminum (Al).
claim 10
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/817,941 US20010010181A1 (en) | 1997-05-30 | 2001-03-27 | Method and system for producing steel having low nitrogen content |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US86617397A | 1997-05-30 | 1997-05-30 | |
US97977197A | 1997-11-26 | 1997-11-26 | |
US27203199A | 1999-03-18 | 1999-03-18 | |
US09/817,941 US20010010181A1 (en) | 1997-05-30 | 2001-03-27 | Method and system for producing steel having low nitrogen content |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US27203199A Continuation | 1997-05-30 | 1999-03-18 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20010010181A1 true US20010010181A1 (en) | 2001-08-02 |
Family
ID=27402435
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/817,941 Abandoned US20010010181A1 (en) | 1997-05-30 | 2001-03-27 | Method and system for producing steel having low nitrogen content |
Country Status (1)
Country | Link |
---|---|
US (1) | US20010010181A1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050078843A1 (en) * | 2003-02-05 | 2005-04-14 | Natan Bauman | Hearing aid system |
WO2005078142A1 (en) * | 2004-02-11 | 2005-08-25 | Tata Steel Limited | A cored wire injection process ih steel melts |
US20060124208A1 (en) * | 2004-12-14 | 2006-06-15 | Coe C L | Method for making strain aging resistant steel |
US20070074599A1 (en) * | 2003-11-06 | 2007-04-05 | Djamschid Amirzadeh-Asl | Method for the introduction of inorganic solid bodies into hot liquid melts |
US20110192255A1 (en) * | 2008-10-09 | 2011-08-11 | National Institute Of Advanced Industrial Science And Technology | Composition for collecting metal component |
US8623113B2 (en) | 2010-03-31 | 2014-01-07 | National Institute Of Advanced Industrial Science And Technology | Metal component collection agent and method for collecting metal component |
CN107099642A (en) * | 2017-04-27 | 2017-08-29 | 攀钢集团研究院有限公司 | Immersion feeds silk braid pipe, wire feeder and feeds silk method |
-
2001
- 2001-03-27 US US09/817,941 patent/US20010010181A1/en not_active Abandoned
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20050078843A1 (en) * | 2003-02-05 | 2005-04-14 | Natan Bauman | Hearing aid system |
US20070074599A1 (en) * | 2003-11-06 | 2007-04-05 | Djamschid Amirzadeh-Asl | Method for the introduction of inorganic solid bodies into hot liquid melts |
US7682418B2 (en) | 2004-02-11 | 2010-03-23 | Tata Steel Limited | Cored wire injection process in steel melts |
WO2005078142A1 (en) * | 2004-02-11 | 2005-08-25 | Tata Steel Limited | A cored wire injection process ih steel melts |
US20080105086A1 (en) * | 2004-02-11 | 2008-05-08 | Tata Steel Limited | Cored Wire Injection Process in Steel Melts |
US7717976B2 (en) | 2004-12-14 | 2010-05-18 | L&P Property Management Company | Method for making strain aging resistant steel |
US20060124208A1 (en) * | 2004-12-14 | 2006-06-15 | Coe C L | Method for making strain aging resistant steel |
US20100193080A1 (en) * | 2004-12-14 | 2010-08-05 | L&P Property Management Company | Method for Making Strain Aging Resistant Steel |
US8419870B2 (en) | 2004-12-14 | 2013-04-16 | L&P Property Management Company | Method for making strain aging resistant steel |
US20110192255A1 (en) * | 2008-10-09 | 2011-08-11 | National Institute Of Advanced Industrial Science And Technology | Composition for collecting metal component |
US8979974B2 (en) | 2008-10-09 | 2015-03-17 | National Institute Of Advanced Industrial Science And Technology | Composition for collecting metal component |
US8623113B2 (en) | 2010-03-31 | 2014-01-07 | National Institute Of Advanced Industrial Science And Technology | Metal component collection agent and method for collecting metal component |
CN107099642A (en) * | 2017-04-27 | 2017-08-29 | 攀钢集团研究院有限公司 | Immersion feeds silk braid pipe, wire feeder and feeds silk method |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20010010181A1 (en) | Method and system for producing steel having low nitrogen content | |
KR950013823B1 (en) | Method of making steel | |
JP2006206957A (en) | Method for recovering manganese from slag produced when manufacturing manganese-based ferroalloy | |
JPS61250107A (en) | Method and apparatus for producing steel from sponge iron | |
AU743299B2 (en) | Method and article for introducing denitrogenizing flux into molten metal | |
US20130167688A1 (en) | Method of making low carbon steel using ferrous oxide and mineral carbonates | |
US4795491A (en) | Premelted synthetic slag for ladle desulfurizing molten steel | |
JP4894325B2 (en) | Hot metal dephosphorization method | |
JPH10130714A (en) | Production of steel for wire rod excellent in wire drawability and cleanliness | |
EP0073274B1 (en) | Method of preliminary desiliconization of molten iron by injecting gaseous oxygen | |
AU3704602A (en) | Method and article for introducing denitrogenizing flux into molten metal | |
US4726033A (en) | Process to improve electric arc furnace steelmaking by bottom gas injection | |
MXPA99011035A (en) | Method and article for introducing denitrogenizing flux into molten metal | |
JPH07207316A (en) | Wire for desulfurization of molten iron having high desulfurization efficiency | |
JP2000345224A (en) | Method for desulfurizing molten iron | |
JP3233304B2 (en) | Production of low Si, low S, and high Mn hot metal with smelting reduction of Mn ore | |
KR100336855B1 (en) | Flux wire for use in the manufacture of high purity aluminum deoxidized steel | |
JP3680385B2 (en) | Demanganese process for hot metal | |
JP5387045B2 (en) | Manufacturing method of bearing steel | |
JP4561135B2 (en) | Refractory-coated immersion lance and hot metal treatment apparatus including the same | |
SU1027227A1 (en) | Method for making steel | |
CN1665942B (en) | Metallurgical treatment method on a metal bath | |
KR970004985B1 (en) | Method of denitrification and dephosphorization | |
JP4197396B2 (en) | Blowing process management method | |
KR20050037076A (en) | Method for manufacturing steel with low sulfur |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SMS DEMAG, INC., PENNSYLVANIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:AG INDUSTRIES, INC.;REEL/FRAME:013467/0600 Effective date: 20020731 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |