CN115044740B - Endpoint carbon control method for low-carbon annealing-free steel converter - Google Patents
Endpoint carbon control method for low-carbon annealing-free steel converter Download PDFInfo
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- CN115044740B CN115044740B CN202210700853.0A CN202210700853A CN115044740B CN 115044740 B CN115044740 B CN 115044740B CN 202210700853 A CN202210700853 A CN 202210700853A CN 115044740 B CN115044740 B CN 115044740B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
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- 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
- C21C7/0006—Adding metallic additives
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- 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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention provides a method for controlling the terminal carbon of a low-carbon annealing-free steel converter, which comprises the steps of (1) adjusting the distribution of bottom blowing air bricks of the converter and a bottom blowing air supply mode, wherein (1) adjusting slag remaining, process feeding, terminal carbon gun position pulling and oxygen supply modes, step (2) adjusting a calcium treatment mode, and step (3) wrapping a heat preservation process. The carbon content of the finished product of the annealing-free low-carbon steel refining is controlled below 0.055 percent, and the carbon content is improved to 99 percent from 80 percent.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a method for controlling endpoint carbon of a low-carbon annealing-free steel converter.
Background
Household appliances, furniture screws or special-shaped parts with strength level below 4.8 in the current market are produced by adopting low-carbon steel, and the processing process needs annealing treatment, so that the processing cost is high. The related published technologies for the end point carbon stability control of a low-carbon steel converter at present are as follows: CN110468335a discloses a smelting method for stably controlling carbon content of low-carbon steel: and (3) a converter: adding steelmaking raw materials into a converter for smelting, carrying out bottom argon blowing and stirring in the whole process, controlling the tapping temperature to be 1630.01-0.03% and the tapping temperature to be 1630-1660 ℃, and sequentially adding deoxidizing agent, low-carbon alloy and slag along with steel flow during tapping for 1/4, wherein a sliding plate slag blocking operation is adopted during tapping; (2) LF refining: deoxidizing the aluminum particle and ferrosilicon powder slag surface, ensuring refining time to be more than or equal to 35 minutes, carrying out argon blowing operation after component and temperature adjustment, using a ladle covering agent during soft blowing, and ensuring proper ladle mixing temperature after soft blowing; (3) continuous casting: and (5) casting the steel in a whole process to obtain the finished steel.
However, the main difficulty in producing annealing-free low-carbon steel in the LF refining furnace billet continuous casting process route is that the control of the terminal carbon of the converter is unstable, and the uniformity of the components of molten steel in the terminal furnace is poor. The method for stabilizing the end point carbon control of the low-carbon steel converter generally comprises the steps of 1, optimizing a converter bottom blowing mode, 2, optimizing a slag remaining and process charging mode, 3, optimizing a smelting gun position and an oxygen supply mode, 4, combining flue gas analysis, enhancing end point gun lifting control, and the partial method for the end point carbon control of the low-carbon steel converter is practiced in a plurality of steel plants in China, and has obvious effects. Therefore, the stable control process of the converter endpoint carbon is a technical core for producing the annealing-free low-carbon steel. In order to reduce the processing cost, the carbon content of the low-carbon steel finished product needs to be controlled below 0.055%, the annealing treatment is avoided in the processing process, the low-carbon steel finished product needs to be controlled in the conventional production, RH vacuum treatment is needed, and the single-furnace production period is long. In addition, the end point carbon control of the annealing-free low-carbon steel XM06BA is unstable, and the uniformity of end point components is poor, so that the refined finished product C is more than or equal to 0.056%, and the degradation and judgment accidents are frequent.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention provides a method for controlling the endpoint carbon of a low-carbon annealing-free steel converter.
A method for controlling the endpoint carbon of a low-carbon annealing-free steel converter comprises the following steps of (1) the converter: adding steelmaking raw materials into a converter for smelting, performing full-process bottom blowing argon stirring, adjusting the arrangement of bottom blowing air bricks of the converter, controlling the bottom blowing flow of the converter according to the oxygen blowing step of the converter, adjusting the smelting slag remaining and process feeding mode, controlling tapping, adjusting the terminal carbon gun drawing position and the oxygen supplying mode, and determining the oxygen closing point of the terminal gun lifting by combining smoke analysis components; step (2) LF refining: deoxidizing aluminum particles and ferrosilicon powder slag surfaces, controlling refining time, performing calcium treatment by using pure calcium aluminum wires after components and temperature are adjusted, adjusting soft blowing time, and promoting floating of inclusions; and (3) continuous casting: the whole process protects and casts to obtain the finished steel, and the tundish heat preservation process is adjusted;
the method is characterized in that:
the step (1) is to adjust the distribution of the bottom blowing air bricks of the converter and the bottom blowing air supply mode as follows: 3 bottom blowing elements on each side of the 6 converter are distributed in an eccentric triangle; controlling the bottom blowing flow of the smelting oxygen step converter;
the slag remaining and process charging mode of the step (1) is as follows: after tapping, adopting a primary slag splashing mode, and pouring slag to 170 degrees after slag splashing, wherein the slag quantity is 2t; lime in the smelting process is controlled;
the saidThe adjusting terminal carbon gun position and oxygen supply mode in the step (1) are as follows: the carbon gun position at the end point is reduced to 0.8m compared with the normal gun position, and the oxygen supply flow is increased to 30000Nm 3 /h；
And (2) determining an end point gun lifting control by combining the smoke analysis in the step (1) as follows: when the CO content in the flue gas at the end point is reduced to below 5%, the gun is lifted, and the carbon at the end point can be stably controlled to be 0.03% -0.04%.
The pure calcium aluminum wire calcium treatment process in the step (2) comprises the following steps: starting the first furnace, feeding 450-500 m, and continuously casting 300-350 m each furnace.
The medium package heat preservation process in the step (3) comprises the following steps: adding a low-carbon low-silicon covering agent, then adding a high-performance covering agent, covering asbestos cloth at each baking hole, and keeping the black surface operation of a tundish casting area and an impact area in the casting process.
Further, the bottom blowing flow rate of the converter in the smelting oxygen step in the step (1) is specifically controlled to be 550Nm, wherein the bottom blowing flow rate of the converter in the smelting oxygen step is 0-70 percent 3 And/h, controlling the bottom blowing flow of the converter at 650Nm in the smelting oxygen step of 71-100 percent 3 /h。
Further, in the step (1), lime is specifically controlled in the smelting process, the addition amount of light burned dolomite is controlled to be 2000-2200 Kg, and limestone is controlled to be 1500Kg.
Further, in the step (2), the pure calcium aluminum wire calcium treatment process ensures that the startup calcium aluminum ratio is more than or equal to 0.12 and the continuous casting calcium aluminum ratio is more than or equal to 0.09.
The invention can realize the control method of the end point carbon of the low-carbon annealing-free steel converter, and the carbon content of the finished annealing-free low-carbon steel refining product is controlled below 0.055 percent, and the carbon content is improved to 99 percent from 80 percent.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a graph showing the effect of controlling the carbon content of the finished converter product according to the present invention.
Detailed Description
The invention will be further described with reference to the drawings and examples.
Examples
Low-carbon annealing-free steel converter endThe spot carbon control method comprises the following steps of (1) a converter in the step (1): adding steelmaking raw materials into a converter for smelting, performing full-process bottom blowing argon stirring, adjusting the arrangement of bottom blowing air bricks of the converter, controlling the bottom blowing flow of the converter according to the oxygen blowing step of the converter, adjusting smelting slag and process charging modes, and controlling tapping; adjusting the distribution of bottom blowing air bricks of the converter and the bottom blowing air supply mode, and distributing 3 bottom blowing elements of the converter in an eccentric triangle shape on each side; controlling the low blowing flow of the smelting oxygen step converter; the bottom blowing flow of the converter with 0-70% of smelting oxygen step is controlled at 550Nm 3 And/h, controlling the bottom blowing flow of the converter at 650Nm in the smelting oxygen step of 71-100 percent 3 /h; the slag-reserving and process-charging modes are regulated, a primary slag-splashing mode is adopted after tapping is finished, slag is splashed to 170 degrees after slag is splashed, and the slag-reserving amount is 2t; lime in the smelting process is controlled; the addition amount of the light burned dolomite is controlled to be 2000-2200 Kg, and the limestone is controlled to be 1500Kg; adjusting the carbon gun position and the oxygen supply mode of the end point; adjusting the terminal carbon pulling gun position and the oxygen supply mode, reducing the terminal carbon pulling gun position to 0.8m compared with the normal gun position, and increasing the oxygen supply flow to 30000Nm 3 /h; determining an oxygen closing point of the terminal gun lifting by combining the smoke analysis components; when the CO content in the flue gas at the end point is reduced to below 5%, lifting the gun, and stably controlling the carbon at the end point to be 0.03% -0.04%; step (2) LF refining: deoxidizing aluminum particles and ferrosilicon powder slag surfaces, controlling refining time, performing calcium treatment by using pure calcium aluminum wires after components and temperature are regulated, starting a first furnace, feeding 450-500 m, and continuously casting 300-350 m each furnace; ensuring that the starting-up calcium-aluminum ratio is more than or equal to 0.12, and the continuous casting calcium-aluminum ratio is more than or equal to 0.09; and (3) continuous casting: and (3) protecting and casting in the whole process to obtain finished steel, adjusting a tundish heat preservation process, adding a low-carbon low-silicon covering agent, and then adding a high-performance covering agent, wherein each baking hole is required to cover asbestos cloth, and the tundish casting area and the impact area are required to operate in a black surface in the casting process.
The invention can realize the control method of the end point carbon of the low-carbon annealing-free steel converter, the carbon content of the finished product of the annealing-free low-carbon steel refining is controlled to be less than 0.055 percent, the ratio is improved to 99 percent from 80 percent, and the effect is shown in figure 2, and the carbon content of the finished product of the converter is controlled (unit: 0.01 percent) to be less than 0.055 percent.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same; while the invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that: modifications may be made to the specific embodiments of the present invention or equivalents may be substituted for part of the technical features thereof; without departing from the spirit of the invention, it is intended to cover the scope of the invention as claimed.
Claims (4)
1. A method for controlling the endpoint carbon of a low-carbon annealing-free steel converter comprises the following steps of (1) the converter: adding steelmaking raw materials into a converter for smelting, performing full-process bottom blowing argon stirring, adjusting the arrangement of bottom blowing air bricks of the converter, controlling the bottom blowing flow of the converter according to the oxygen blowing step of the converter, adjusting the smelting slag remaining and process feeding mode, controlling tapping, adjusting the terminal carbon gun drawing position and the oxygen supplying mode, and determining the oxygen closing point of the terminal gun lifting by combining smoke analysis components; step (2) LF refining: deoxidizing aluminum particles and ferrosilicon powder slag surfaces, controlling refining time, performing calcium treatment by using pure calcium aluminum wires after components and temperature are adjusted, adjusting soft blowing time, and promoting floating of inclusions; and (3) continuous casting: the whole process protects and casts to obtain the finished steel, and the tundish heat preservation process is adjusted;
the method is characterized in that:
the step (1) is to adjust the distribution of the bottom blowing air bricks of the converter and the bottom blowing air supply mode as follows: 3 bottom blowing elements on each side of the 6 converter are distributed in an eccentric triangle; controlling the bottom blowing flow of the smelting oxygen step converter;
the slag remaining and process charging mode of the step (1) is as follows: after tapping, adopting a primary slag splashing mode, and pouring slag to 170 degrees after slag splashing, wherein the slag quantity is 2t; lime in the smelting process is controlled;
the adjusting terminal carbon gun position and oxygen supply mode in the step (1) are as follows: the carbon gun position at the end point is reduced to 0.8m compared with the normal gun position, and the oxygen supply flow is increased to 30000Nm 3 /h；
And (2) determining an end point gun lifting control by combining the smoke analysis in the step (1) as follows: when the CO content in the flue gas at the end point is reduced to below 5%, lifting the gun, and stably controlling the carbon at the end point to be 0.03% -0.04%;
the pure calcium aluminum wire calcium treatment process in the step (2) comprises the following steps: starting the first furnace, feeding 450-500 m, and continuously casting 300-350 m of each furnace;
the medium package heat preservation process in the step (3) comprises the following steps: the low-carbon low-silicon covering agent is added firstly, then the high-performance covering agent is added, the asbestos cloth is covered in each baking hole, and the black surface operation of the pouring area and the impact area of the tundish is kept in the pouring process.
2. The method for controlling the endpoint carbon of the low-carbon annealing-free steel converter according to claim 1, which is characterized by comprising the following steps: the low blowing flow rate of the converter for smelting the oxygen step in the step (1) is specifically that the bottom blowing flow rate of the converter for smelting the oxygen step of 0-70% is controlled at 550Nm 3 And/h, controlling the bottom blowing flow of the converter at 650Nm in the smelting oxygen step of 71-100 percent 3 /h。
3. The method for controlling the endpoint carbon of the low-carbon annealing-free steel converter according to claim 1, which is characterized by comprising the following steps: in the step (1), lime is specifically controlled in the smelting process, the addition amount of light burned dolomite is controlled to be 2000-2200 Kg, and limestone is controlled to be 1500Kg.
4. The method for controlling the endpoint carbon of the low-carbon annealing-free steel converter according to claim 1, which is characterized by comprising the following steps: in the pure calcium aluminum wire calcium treatment process in the step (2), the starting-up calcium aluminum ratio is more than or equal to 0.12, and the continuous casting calcium aluminum ratio is more than or equal to 0.09.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210700853.0A CN115044740B (en) | 2022-06-20 | 2022-06-20 | Endpoint carbon control method for low-carbon annealing-free steel converter |
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| CN202210700853.0A CN115044740B (en) | 2022-06-20 | 2022-06-20 | Endpoint carbon control method for low-carbon annealing-free steel converter |
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| CN115044740B true CN115044740B (en) | 2023-08-25 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20190076314A (en) * | 2017-12-22 | 2019-07-02 | 주식회사 포스코 | Method for Refining Low Carbon Steel |
| CN110093473A (en) * | 2019-03-21 | 2019-08-06 | 首钢京唐钢铁联合有限责任公司 | The production method of high nitrogen tinplate |
| CN110468335A (en) * | 2019-09-18 | 2019-11-19 | 中天钢铁集团有限公司 | A kind of smelting process of mild steel carbon content stability contorting |
| CN114606357A (en) * | 2022-03-20 | 2022-06-10 | 新疆八一钢铁股份有限公司 | Method for removing phosphorus and leaving carbon in medium-high carbon steel by converter |
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- 2022-06-20 CN CN202210700853.0A patent/CN115044740B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20190076314A (en) * | 2017-12-22 | 2019-07-02 | 주식회사 포스코 | Method for Refining Low Carbon Steel |
| CN110093473A (en) * | 2019-03-21 | 2019-08-06 | 首钢京唐钢铁联合有限责任公司 | The production method of high nitrogen tinplate |
| CN110468335A (en) * | 2019-09-18 | 2019-11-19 | 中天钢铁集团有限公司 | A kind of smelting process of mild steel carbon content stability contorting |
| CN114606357A (en) * | 2022-03-20 | 2022-06-10 | 新疆八一钢铁股份有限公司 | Method for removing phosphorus and leaving carbon in medium-high carbon steel by converter |
Non-Patent Citations (1)
| Title |
|---|
| SWRCH22A冷镦钢转炉冶炼一次拉碳工艺研究;严建新;胡友红;;金属制品(03);全文 * |
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