CA1288954C - Process for producing high-quality steel - Google Patents
Process for producing high-quality steelInfo
- Publication number
- CA1288954C CA1288954C CA000522224A CA522224A CA1288954C CA 1288954 C CA1288954 C CA 1288954C CA 000522224 A CA000522224 A CA 000522224A CA 522224 A CA522224 A CA 522224A CA 1288954 C CA1288954 C CA 1288954C
- Authority
- CA
- Canada
- Prior art keywords
- melt
- carbon
- process according
- oxygen
- carbon content
- 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.)
- Expired - Lifetime
Links
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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/32—Blowing from above
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
ABSTRACT
The invention is concerned with a process for producing high-quality steel having a pre-selected carbon content from a melt. The process of the invention comprises decarburizing a melt in a converter by top-blowing the melt with oxygen such that the carbon content of the melt is lowered to less than about 0.1% carbon. A slag is created on the melt and carbon is delivered into the melt at a high velocity whereby the melt and the slag mix, the carbon being delivered to the melt until the oxygen content of the melt is less than or equal to about 250-400 ppm oxygen and the carbon content of the melt is greater than or equal to about 0.04-0.07% carbon. Recarburization of the melt is then effected in either the converter or a ladle whereby a melt containing as little oxygen as is reasonably possible and having a carbon content which is as close as possible to a pre-selected carbon content is achieved. the melt upon meeting such requirements is finally transferred to a ladle and treated both with a synthetic slag and with a material that is both deoxidizing and desulphurizing.
The invention is concerned with a process for producing high-quality steel having a pre-selected carbon content from a melt. The process of the invention comprises decarburizing a melt in a converter by top-blowing the melt with oxygen such that the carbon content of the melt is lowered to less than about 0.1% carbon. A slag is created on the melt and carbon is delivered into the melt at a high velocity whereby the melt and the slag mix, the carbon being delivered to the melt until the oxygen content of the melt is less than or equal to about 250-400 ppm oxygen and the carbon content of the melt is greater than or equal to about 0.04-0.07% carbon. Recarburization of the melt is then effected in either the converter or a ladle whereby a melt containing as little oxygen as is reasonably possible and having a carbon content which is as close as possible to a pre-selected carbon content is achieved. the melt upon meeting such requirements is finally transferred to a ladle and treated both with a synthetic slag and with a material that is both deoxidizing and desulphurizing.
Description
The present invention relates to a process for producing high-quality steel using an oxygen top-blowing procedure.
In the present invention and for purposes of this application, high quality steel is defined as a steel which contains as little phosphorus, sulphur and non-metallic inclusions as is reasonably possible.
A known method for achieving the desired carbon content in a melt comprises discontinuing the decarburizing process step at a pre-selected time. However, a disadvantage or drawback of this method is that it does not permit the production of steels having both high carbon and low phosphorus contents. Nevertheless, if it is desired to obtain steels having low phosphorus content, a pre-treatment (dephosphorizing, desulphurizing, desilicizing) of the hot metal melt is necessary. Such pre-treatments, which have been described primarily by Japanese steelmakers in various printed documents, are performed outside of steelmaking converters, in stationary or transportable ladles, and generate high costs due in part to the expensive apparatus which must be used. It will be appreciated that the inevita-ble temperature losses inherent to such processes have to be either borne or compensated through heating devices, thus leading to increased costs and further disadvantages. It should be noted that only by using the method described above wherein the desired carbon content is obtained through discontinuing the decarburization step, will low inclusion (phosphorus) contents steel also be obtained.
~Zl3~3~354 Another known method which allows low phosphorus contents in steel to be obtained at lower costs, involves decarburizing the steel down to low carbon-contents, e.g.
0.05% C. However, with this method, the decarburized steel will contain relatively high amounts of oxygen, depending upon the conditions (for examp]e, 500 to 1000 ppm, and even more),- the removal of which through conventional means not only requires large amounts of expensive substances, but also generates undesired inclusions.
It is an object of the present invention to overcome or alleviate the above discussed and other problems and deficiencies of the prior art and to provide a process which permits the production of high-quality steel, with a minimum content of non-metallic inclusions.
In accordance with the present invention, there is thus provided a process for producing high-quality steel having a pre-selected carbon content from a melt, which comprises a first step of decarburizing a melt in a con-verter by top-blowing said melt with oxygen such that the carbon content of said melt is lowered to less than about 0.1% carbon. Next, a slag is created on the melt and carbon is delivered into the melt at a high velocity whereby the melt and the slag mix, the carbon being delivered to the melt until the oxygen content of the melt is less than or equal to about 250-400 ppm oxygen and the carbon content of the melt is greater than or equal to about 0.04-0.07~
carbon. In a third step, recarburization of the melt is effected whereby a melt containing as little oxygen as is reasonably possible and having a carbon content which is as close as possible to a pre-selected carbon content is ~Z8E~9~
achieved. In a fourth optional step, the melt upon meeting such requirements is transferred to a ladle and treated both with a synthetic slag and with a material that is both deoxidizing and desulphurizing.
The first step of the process according to the present invention comprises decarburizing of the melt in a converter, by top-blowing oxygen and adding the well-known substances necessary to convert silicon and phosphorus into slag. The decarburization step generates heat and the resultant slag becomes reactive due to the oxygen input, thereby absorbing a portion of the phosphorus. The decarbu-rization step is contlnued to produce a carbon content lower than about 0.1~ C, preferably lower than 0.05~ C, regardless of the final carbon content which is desired in the finished steel.
The second step in the present invention comprises treating the decarburized an oxygen-enriched melt with carbon, within the converter. This process step is performed by introducing into the melt, at the highest velocity possible, carbon which is preferably in the form of comminu-ted coal such as anthracite. This second step generates an extraordinarily vehement reaction during which the metal bath is both deoxidized and recarburized. It will be ap-preciated that contrary to conventional deoxidization in a ladle with combinations of coal, ferromanganese, ferrosili-con, aluminum and the like, the products of deoxidization are exclusively gaseous in the instant case and will there-fore not yield inclusions. In this step, high amounts of carbon monoxide are generated, which result in a forceful mixing of the metal phase with the slag phase.
~288954 In accordance with the inventlon, care is taken to profit from the slag reactivity. The reaction of the second step is thus performed with the purpose of obtaining a strong stir and an intense mixing of the bath with the slag.
An advantageous method comprises top-blowing the carbon through a special lance, wherein the carbon particles are suspended in an inert gas and are accelerated to high speeds. It has been found advantageous to further bottom-blow an inert gas in the melt during the addition of carbon, in order to even further improve mixing of the bath and slag.
The second step is ceased at an oxygen-content of about 250-400 ppm oxygen. At this point, the melt still has a very low carbon content, e.g. about 0.04-0.07% C. It has been observed that during the addition of carbon in the second step, the carbon at first primarily deoxidizes the melt before recarburizing the same. In fact, the combination of the coal injection and the bottom-stirring result in lowering the product carbon: oxygen ratio to its thermo-dynamic equilibrium value in accordance with the actual temperature and gas pressure conditions in the metal bath.
For example, prior to coal addition: %carbon=0.032i ppm oxygen=900; after coal addition: ~carbon=0.057; ppm oxygen=350. Significantly, at the same time, it has been observed that a surprisingly high dephosphorization of the bath has occurred.
If especially low phosphorus content is desired, for example, 0.008% P or less, in accordance with the present invention, a Na2O-bearing material (i.e. suitable lZ8895~L
known compounds that yield Na2 upon thermal decomposition) will be added. These may be added for example, by top-blowing, together with the carbon.
The third step in the process of the invention comprises a treatment of the deoxidized and partly decarbu-rized bath (taking into consideration the actual conditions relati-ve to bath temperature, oxygen content, carbon content, etc.). It will be appreciated that the ratio of carbon:oxygen at a given temperature will be important with regard to the remainder of the process.
It will also be appreciated that one of the primary objects of the present invention is to suppress the tendency of the steel to form inclusions. As a consequence, the melt will be transferred to a ladle only upon containing as little oxygen as possible and having a carbon content as close to the desired content as possible. Preferably, the ladle should be free from any heating means. In order to avoid producing solid deoxidation products, the deoxidation should be carried out with carbon as far as feasible, thus creating only carbon monoxide and carbon dioxide.
Thus, in a first embodiment of the process ac-cording to the present invention, treatment of the melt with carbon continues within the converter, until the desired carbon content is reached. If this desired content is, for example, close to 0.10~ C, the corresponding oxygen content will be close to 200 ppm O. Thereafter, the melt is transferred into the ladle.
A second embodiment of the present invention comprises continuing the treatment of the melt with carbon in the ladle, so as to limit the amounts of carbon injected in the converter. In that case, the entire amount of carbon is added in the form of a commercially available recarburi-zer, during the transfer in the ladle and prior to adding alloying materials.
Whether the third process step is carried out in a converter or in a ladle, surprisingly, the rephosphorization that $hould normally be expected does not occur. It is believed that this unexpected result is because the second step does not only entail conversion of carbon and oxygen to carbon monoxide and carbon dioxide, plus a dissolution of carbon in iron, but also there occurs some type of inter-action between the slag and the carbon. It is further believed that this interaction at first is due to a strong reactivity towards phosphorus and also partially sulphur, and at a certain time has a maximum intensity, and towards the end of the treatment turns into a pronounced passivity.
At the term of the treatment, the slag is passive and will not pass on phosphorus to the melt, despite a treatment with reducing materials.
This passivity also influences the carbon: oxygen equilibrium in the converter through addition of materials such as ferromanganese, by injecting these materials in the melt and permits a lowering of the oxygen-content of the bath, while preserving its carbon content, and not suffering from rephosphorization. While this phenomenon generates solid deoxidization products, due to the still elevated bath temperature and to the bath-diameter; bath-height ratio (which is more favorable in the converter than in the iZ8~3~5~
ladle), these deoxidization products do not turn into inclusions in the finished steel, but precipitate entirely and are absorbed in the slag.
Finally, in a fourth optional step of the process according to the present invention, the melt is treated in a ladle with a deoxidizing and desulphurizing agent, prefer-ably with metallic calcium, and with well known synthetic slags. As a result, the renewed oxygen-surplus twhich is due to the inevitable temperature drop) is removed leading to the creation of relatively large globular oxidized products.
It will be appreciated that large globular bodies will more readily rise and precipitate from the metal phase than small or non-globular particles.
The above-described process of the present inven-tion can be used in order to manufacture both semi-killed and fully killed steels.
The following non-limiting example further illus-trates the invention.
EXAMPLE
1) Decarburizing (in the converter) end of blow 0 in steel 950 (ppm) C in steel 0.034 (~) P in steel 0.022 (~) Temperature 1700 ( C) ~2~38~
In the present invention and for purposes of this application, high quality steel is defined as a steel which contains as little phosphorus, sulphur and non-metallic inclusions as is reasonably possible.
A known method for achieving the desired carbon content in a melt comprises discontinuing the decarburizing process step at a pre-selected time. However, a disadvantage or drawback of this method is that it does not permit the production of steels having both high carbon and low phosphorus contents. Nevertheless, if it is desired to obtain steels having low phosphorus content, a pre-treatment (dephosphorizing, desulphurizing, desilicizing) of the hot metal melt is necessary. Such pre-treatments, which have been described primarily by Japanese steelmakers in various printed documents, are performed outside of steelmaking converters, in stationary or transportable ladles, and generate high costs due in part to the expensive apparatus which must be used. It will be appreciated that the inevita-ble temperature losses inherent to such processes have to be either borne or compensated through heating devices, thus leading to increased costs and further disadvantages. It should be noted that only by using the method described above wherein the desired carbon content is obtained through discontinuing the decarburization step, will low inclusion (phosphorus) contents steel also be obtained.
~Zl3~3~354 Another known method which allows low phosphorus contents in steel to be obtained at lower costs, involves decarburizing the steel down to low carbon-contents, e.g.
0.05% C. However, with this method, the decarburized steel will contain relatively high amounts of oxygen, depending upon the conditions (for examp]e, 500 to 1000 ppm, and even more),- the removal of which through conventional means not only requires large amounts of expensive substances, but also generates undesired inclusions.
It is an object of the present invention to overcome or alleviate the above discussed and other problems and deficiencies of the prior art and to provide a process which permits the production of high-quality steel, with a minimum content of non-metallic inclusions.
In accordance with the present invention, there is thus provided a process for producing high-quality steel having a pre-selected carbon content from a melt, which comprises a first step of decarburizing a melt in a con-verter by top-blowing said melt with oxygen such that the carbon content of said melt is lowered to less than about 0.1% carbon. Next, a slag is created on the melt and carbon is delivered into the melt at a high velocity whereby the melt and the slag mix, the carbon being delivered to the melt until the oxygen content of the melt is less than or equal to about 250-400 ppm oxygen and the carbon content of the melt is greater than or equal to about 0.04-0.07~
carbon. In a third step, recarburization of the melt is effected whereby a melt containing as little oxygen as is reasonably possible and having a carbon content which is as close as possible to a pre-selected carbon content is ~Z8E~9~
achieved. In a fourth optional step, the melt upon meeting such requirements is transferred to a ladle and treated both with a synthetic slag and with a material that is both deoxidizing and desulphurizing.
The first step of the process according to the present invention comprises decarburizing of the melt in a converter, by top-blowing oxygen and adding the well-known substances necessary to convert silicon and phosphorus into slag. The decarburization step generates heat and the resultant slag becomes reactive due to the oxygen input, thereby absorbing a portion of the phosphorus. The decarbu-rization step is contlnued to produce a carbon content lower than about 0.1~ C, preferably lower than 0.05~ C, regardless of the final carbon content which is desired in the finished steel.
The second step in the present invention comprises treating the decarburized an oxygen-enriched melt with carbon, within the converter. This process step is performed by introducing into the melt, at the highest velocity possible, carbon which is preferably in the form of comminu-ted coal such as anthracite. This second step generates an extraordinarily vehement reaction during which the metal bath is both deoxidized and recarburized. It will be ap-preciated that contrary to conventional deoxidization in a ladle with combinations of coal, ferromanganese, ferrosili-con, aluminum and the like, the products of deoxidization are exclusively gaseous in the instant case and will there-fore not yield inclusions. In this step, high amounts of carbon monoxide are generated, which result in a forceful mixing of the metal phase with the slag phase.
~288954 In accordance with the inventlon, care is taken to profit from the slag reactivity. The reaction of the second step is thus performed with the purpose of obtaining a strong stir and an intense mixing of the bath with the slag.
An advantageous method comprises top-blowing the carbon through a special lance, wherein the carbon particles are suspended in an inert gas and are accelerated to high speeds. It has been found advantageous to further bottom-blow an inert gas in the melt during the addition of carbon, in order to even further improve mixing of the bath and slag.
The second step is ceased at an oxygen-content of about 250-400 ppm oxygen. At this point, the melt still has a very low carbon content, e.g. about 0.04-0.07% C. It has been observed that during the addition of carbon in the second step, the carbon at first primarily deoxidizes the melt before recarburizing the same. In fact, the combination of the coal injection and the bottom-stirring result in lowering the product carbon: oxygen ratio to its thermo-dynamic equilibrium value in accordance with the actual temperature and gas pressure conditions in the metal bath.
For example, prior to coal addition: %carbon=0.032i ppm oxygen=900; after coal addition: ~carbon=0.057; ppm oxygen=350. Significantly, at the same time, it has been observed that a surprisingly high dephosphorization of the bath has occurred.
If especially low phosphorus content is desired, for example, 0.008% P or less, in accordance with the present invention, a Na2O-bearing material (i.e. suitable lZ8895~L
known compounds that yield Na2 upon thermal decomposition) will be added. These may be added for example, by top-blowing, together with the carbon.
The third step in the process of the invention comprises a treatment of the deoxidized and partly decarbu-rized bath (taking into consideration the actual conditions relati-ve to bath temperature, oxygen content, carbon content, etc.). It will be appreciated that the ratio of carbon:oxygen at a given temperature will be important with regard to the remainder of the process.
It will also be appreciated that one of the primary objects of the present invention is to suppress the tendency of the steel to form inclusions. As a consequence, the melt will be transferred to a ladle only upon containing as little oxygen as possible and having a carbon content as close to the desired content as possible. Preferably, the ladle should be free from any heating means. In order to avoid producing solid deoxidation products, the deoxidation should be carried out with carbon as far as feasible, thus creating only carbon monoxide and carbon dioxide.
Thus, in a first embodiment of the process ac-cording to the present invention, treatment of the melt with carbon continues within the converter, until the desired carbon content is reached. If this desired content is, for example, close to 0.10~ C, the corresponding oxygen content will be close to 200 ppm O. Thereafter, the melt is transferred into the ladle.
A second embodiment of the present invention comprises continuing the treatment of the melt with carbon in the ladle, so as to limit the amounts of carbon injected in the converter. In that case, the entire amount of carbon is added in the form of a commercially available recarburi-zer, during the transfer in the ladle and prior to adding alloying materials.
Whether the third process step is carried out in a converter or in a ladle, surprisingly, the rephosphorization that $hould normally be expected does not occur. It is believed that this unexpected result is because the second step does not only entail conversion of carbon and oxygen to carbon monoxide and carbon dioxide, plus a dissolution of carbon in iron, but also there occurs some type of inter-action between the slag and the carbon. It is further believed that this interaction at first is due to a strong reactivity towards phosphorus and also partially sulphur, and at a certain time has a maximum intensity, and towards the end of the treatment turns into a pronounced passivity.
At the term of the treatment, the slag is passive and will not pass on phosphorus to the melt, despite a treatment with reducing materials.
This passivity also influences the carbon: oxygen equilibrium in the converter through addition of materials such as ferromanganese, by injecting these materials in the melt and permits a lowering of the oxygen-content of the bath, while preserving its carbon content, and not suffering from rephosphorization. While this phenomenon generates solid deoxidization products, due to the still elevated bath temperature and to the bath-diameter; bath-height ratio (which is more favorable in the converter than in the iZ8~3~5~
ladle), these deoxidization products do not turn into inclusions in the finished steel, but precipitate entirely and are absorbed in the slag.
Finally, in a fourth optional step of the process according to the present invention, the melt is treated in a ladle with a deoxidizing and desulphurizing agent, prefer-ably with metallic calcium, and with well known synthetic slags. As a result, the renewed oxygen-surplus twhich is due to the inevitable temperature drop) is removed leading to the creation of relatively large globular oxidized products.
It will be appreciated that large globular bodies will more readily rise and precipitate from the metal phase than small or non-globular particles.
The above-described process of the present inven-tion can be used in order to manufacture both semi-killed and fully killed steels.
The following non-limiting example further illus-trates the invention.
EXAMPLE
1) Decarburizing (in the converter) end of blow 0 in steel 950 (ppm) C in steel 0.034 (~) P in steel 0.022 (~) Temperature 1700 ( C) ~2~38~
2) Deoxydation/Dephosphorization (in the converter~
Anthracite 2 (kg/t of steel) Na2O-bearer 6 (kg Na2O/t of steel) Carrier-Gas 0.10 (Nm N2/kg Anthracite) Bottom-stirring gas 0.05 (Nm Ar/t of - steel.Minute) 0 in steel 350 (ppm) C in steel 0.06 (%) P in steel 0.011 (%) Temperature 1660 (C) 3) Recarburizing Anthracite 1.1 (kg/t of steel) Fe-Mn 1.5 (kg/t of steel) Carrier-Gas 0.10 (Nm3N2/kg Anthracite) Bottom-stirring gas 0 (Nm N2/t of steel.Minute) 0 in steel 210 (ppm) C in steel 0.10 (~) Temperature 1645 (C) 4) Accurate recarburizing Anthracite 0.55 (kg/t of steel) 0 in steel 105 (ppm) C in steel 0.14 (%) Temperature 1605 (C) 5) Accurate deoxydization (in the ladle) Ca .45 (kg/t of steel) Synth. slag 1.8 (kg/t of steel) O in steel 3.S (ppm.) S in steel .06 (~) P in steel .012 (%) . .
Anthracite 2 (kg/t of steel) Na2O-bearer 6 (kg Na2O/t of steel) Carrier-Gas 0.10 (Nm N2/kg Anthracite) Bottom-stirring gas 0.05 (Nm Ar/t of - steel.Minute) 0 in steel 350 (ppm) C in steel 0.06 (%) P in steel 0.011 (%) Temperature 1660 (C) 3) Recarburizing Anthracite 1.1 (kg/t of steel) Fe-Mn 1.5 (kg/t of steel) Carrier-Gas 0.10 (Nm3N2/kg Anthracite) Bottom-stirring gas 0 (Nm N2/t of steel.Minute) 0 in steel 210 (ppm) C in steel 0.10 (~) Temperature 1645 (C) 4) Accurate recarburizing Anthracite 0.55 (kg/t of steel) 0 in steel 105 (ppm) C in steel 0.14 (%) Temperature 1605 (C) 5) Accurate deoxydization (in the ladle) Ca .45 (kg/t of steel) Synth. slag 1.8 (kg/t of steel) O in steel 3.S (ppm.) S in steel .06 (~) P in steel .012 (%) . .
Claims (15)
1. A process for producing high-quality steel having a pre-selected carbon content from a melt, comprising the steps of:
a) decarburizing a melt in a converter by top-blowing said melt with oxygen such that the carbon content of said melt is lowered to less than about 0.1% carbon;
b) creating a slag on said melt and delivering carbon into said melt at a high velocity whereby said melt and said slag mix, said carbon being delivered to said melt until the oxygen content of said melt is less than or equal to about 250-400 ppm oxygen and the carbon content of said melt is greater than or equal to about 0.04-0.07% carbon;
and c) recarburizing said melt whereby a melt con-taining as little oxygen as is reasonably possible and having a carbon content which is as close as possible to a pre-selected carbon content is obtained.
a) decarburizing a melt in a converter by top-blowing said melt with oxygen such that the carbon content of said melt is lowered to less than about 0.1% carbon;
b) creating a slag on said melt and delivering carbon into said melt at a high velocity whereby said melt and said slag mix, said carbon being delivered to said melt until the oxygen content of said melt is less than or equal to about 250-400 ppm oxygen and the carbon content of said melt is greater than or equal to about 0.04-0.07% carbon;
and c) recarburizing said melt whereby a melt con-taining as little oxygen as is reasonably possible and having a carbon content which is as close as possible to a pre-selected carbon content is obtained.
2. A process according to claim 1, further including transferring the melt obtained in step (c) to a ladle and treating said melt both with a synthetic slag and with a material that is both deoxidizing and desulphurizing.
3. A process according to claim 2, wherein said deoxidizing and desulphurizing material is metallic calcium.
4. A process according to claim 1, wherein said carbon is coal.
5. A process according to claim 4, wherein said coal is comminuted coal.
6. A process according to claim 5, wherein said comminuted coal is anthracite.
7. A process according to claim 1, wherein step (a) is carried out such that the carbon content of said melt is lowered to less than about 0.05% carbon.
8. A process according to claim 1, wherein said carbon is delivered into said melt by suspending carbon particles in an inert gas and by blowing the suspended carbon particles through a lance onto the melt surface.
9. A process according to claim 1, wherein dephospho-rization occurs in step (b) and wherein said dephospho-rization is enhanced by adding a Na2O-bearing material.
10. A process according to claim 8, wherein dephospho-rization occurs in step (b) and wherein said dephospho-rization is enhanced by adding a Na2O-bearing material.
11. A process according to claim 1, wherein deoxidiza-tion occurs in step (c) and wherein said deoxidization is enhanced by adding ferromanganese.
12. A process according to claim 8, wherein deoxidiza-tion occurs in step (c) and wherein said deoxidization is enhanced by adding ferromanganese.
13. A process according to claim 9, wherein deoxidiza-tion occurs in step (c) and wherein said deoxidization is enhanced by adding ferromanganese.
14. A process according to claims 1 or 8, wherein an inert gas is bottom-blown into the melt during steps (b) and (c), to improve mixing of said melt and said slag.
15. A process according to claim 1, wherein step (c) is accomplished in either a converter or a ladle depending upon temperature, preselected carbon:oxygen ratio and desired pre-selected carbon content.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU86225A LU86225A1 (en) | 1985-12-23 | 1985-12-23 | METHOD FOR PRODUCING HIGH QUALITY STEEL |
| LU86225 | 1985-12-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1288954C true CA1288954C (en) | 1991-09-17 |
Family
ID=19730608
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000522224A Expired - Lifetime CA1288954C (en) | 1985-12-23 | 1986-11-05 | Process for producing high-quality steel |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0226912A3 (en) |
| JP (1) | JPS62158811A (en) |
| AU (1) | AU590801B2 (en) |
| BR (1) | BR8605894A (en) |
| CA (1) | CA1288954C (en) |
| LU (1) | LU86225A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102019215678A1 (en) * | 2019-10-11 | 2021-04-15 | Sms Group Gmbh | Process for dephosphating molten steel during the refining process |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3702243A (en) * | 1969-04-15 | 1972-11-07 | Nat Steel Corp | Method of preparing deoxidized steel |
| AU6823981A (en) * | 1980-03-21 | 1981-10-15 | Nippon Steel Corporation | Multi-stage steel making |
| LU84168A1 (en) * | 1982-05-25 | 1984-03-07 | Arbed | METHOD FOR CARBONING METAL MELTS |
| LU85363A1 (en) * | 1984-05-15 | 1986-01-29 | Arbed | ADAPTER DEVICE FOR SOLID PARTICLE ACCELERATION NOZZLE |
-
1985
- 1985-12-23 LU LU86225A patent/LU86225A1/en unknown
-
1986
- 1986-10-23 AU AU64325/86A patent/AU590801B2/en not_active Ceased
- 1986-11-05 CA CA000522224A patent/CA1288954C/en not_active Expired - Lifetime
- 1986-12-02 BR BR8605894A patent/BR8605894A/en unknown
- 1986-12-05 EP EP86116948A patent/EP0226912A3/en not_active Withdrawn
- 1986-12-22 JP JP30403586A patent/JPS62158811A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0226912A2 (en) | 1987-07-01 |
| AU590801B2 (en) | 1989-11-16 |
| JPS62158811A (en) | 1987-07-14 |
| LU86225A1 (en) | 1987-07-24 |
| AU6432586A (en) | 1987-06-25 |
| BR8605894A (en) | 1987-08-25 |
| EP0226912A3 (en) | 1989-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2166097A1 (en) | Process for producing steel by converter | |
| US4456477A (en) | Production of ultra-low phosphorus steel | |
| CA1288954C (en) | Process for producing high-quality steel | |
| US4604138A (en) | Process for refining hot metal | |
| US4675049A (en) | Process for producing high quality steel | |
| US4397685A (en) | Production of ultra low carbon steel by the basic oxygen process | |
| US4525209A (en) | Process for producing low P chromium-containing steel | |
| EP0087328B1 (en) | Process to produce low hydrogen steel by argon-oxygen decarburization | |
| JPS5834527B2 (en) | Teirinyousennoseizohouhou | |
| KR100267271B1 (en) | The manufacturing method of low carbon steel with high purity | |
| JPS6121285B2 (en) | ||
| US4415359A (en) | Multi-step steelmaking refining method | |
| US3782921A (en) | Production of steel with a controlled phosphorus content | |
| JPS625964B2 (en) | ||
| US4065297A (en) | Process for dephosphorizing molten pig iron | |
| JPH08134528A (en) | Production of extra low carbon steel | |
| JP2842231B2 (en) | Pretreatment of hot metal by bottom-blown gas stirring | |
| US4451288A (en) | Method for producing low hydrogen content in steels produced by subsurface pneumatic refining | |
| JP3470599B2 (en) | Hot metal desiliconization method | |
| SU1125257A1 (en) | Method for smelting low-carbon steel in converter | |
| CA1075012A (en) | Process for dephosphorizing molten pig iron | |
| Mustata et al. | The features of physico-chemical processes during the combined oxygen blow steelmaking | |
| JPH03120307A (en) | Steelmaking method | |
| JPS6396211A (en) | De-phosphorizing method for molten metal containing chromium | |
| Bannenberg et al. | Operating Results of Vacuum Decarburization in Ladle Stand Degassing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |