CN115044740A - Terminal carbon control method for low-carbon annealing-free steel converter - Google Patents
Terminal carbon control method for low-carbon annealing-free steel converter Download PDFInfo
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- CN115044740A CN115044740A CN202210700853.0A CN202210700853A CN115044740A CN 115044740 A CN115044740 A CN 115044740A CN 202210700853 A CN202210700853 A CN 202210700853A CN 115044740 A CN115044740 A CN 115044740A
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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
Abstract
The invention provides a terminal carbon control method for a low-carbon annealing-free steel converter, which comprises the steps of (1) adjusting distribution of bottom-blown air bricks and a bottom-blown air supply mode of the converter, adjusting slag retention, process feeding, terminal carbon drawing gun position and an oxygen supply mode in the step (1), adjusting a calcium treatment mode in the step (2), and performing a tundish heat preservation process in the step (3). The proportion of the carbon content of the produced non-annealed low carbon steel refined finished product controlled below 0.055 percent is improved from 80 percent to 99 percent.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a method for controlling end point carbon of a low-carbon annealing-free steel converter.
Background
At present, household appliances, furniture screws or special-shaped products with strength grade below 4.8 grade in the market are produced by low-carbon steel, annealing treatment is needed in the processing process, and the processing cost is high. The prior art for controlling the stability of the end point carbon of the low-carbon steel converter comprises the following relevant public technologies: CN110468335A, discloses a smelting method for stably controlling the carbon content of low-carbon steel, which comprises the following steps: converter: adding steelmaking raw materials into a converter for smelting, blowing argon for stirring at the bottom of the whole process, controlling the tapping [ C ] to be 0.01-0.03%, controlling the tapping temperature to be 1630-1660 ℃, sequentially adding a deoxidizer, a low-carbon alloy and slag charge along with steel flow during tapping 1/4, and adopting a sliding plate for slag stopping operation in the tapping process; (2) LF refining: deoxidizing by adopting the slag surfaces of aluminum particles and ferrosilicon powder, ensuring that the refining time is more than or equal to 35 minutes, carrying out argon blowing operation after the components and the temperature are adjusted, using a ladle covering agent during soft blowing, and ensuring proper ladle temperature after soft blowing; (3) continuous casting: and protecting and casting the whole process to obtain finished steel.
However, the main difficulties in producing the annealing-free low-carbon steel in the LF refining furnace billet continuous casting process route are unstable control of the converter end point carbon and poor component uniformity of molten steel in the end point furnace. 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 retention and process feeding mode, 3, optimizing a smelting gun position and an oxygen supply mode, 4, combining flue gas analysis, strengthening the end point gun lifting control, and having obvious effect due to the fact that part of the methods for the end point carbon control of the low-carbon steel converter are practiced in a plurality of domestic steel plants. Therefore, the stable control process of the converter end point carbon is the technical core of producing the annealing-free low-carbon steel. In order to reduce the processing cost, the carbon content of the finished low-carbon steel needs to be controlled below 0.055%, so that the annealing-free treatment in the processing process is realized, the RH vacuum treatment is needed to control the finished low carbon in the conventional production, and the single-furnace production period is longer. In addition, the annealing-free low-carbon steel XM06BA endpoint carbon control is unstable, and the endpoint component uniformity is poor, so that the refined finished product C is more than or equal to 0.056%, and the accidents of degradation and judgment are frequent.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for controlling the end point carbon of a low-carbon non-annealed steel converter.
A terminal carbon control method for a low-carbon annealing-free steel converter comprises the following steps of (1) converter: adding a steelmaking raw material into a converter for smelting, fully blowing argon and stirring, adjusting the arrangement of converter bottom-blown air bricks, controlling the bottom-blown flow of the converter according to the converter blowing oxygen step, adjusting a smelting slag retention and process feeding mode, controlling steel tapping, adjusting a terminal point carbon pulling gun position and an oxygen supply mode, analyzing components by combining smoke, and determining a terminal point gun lifting oxygen-closing point; step (2) LF refining: deoxidizing the slag surface of aluminum particles and ferrosilicon powder, controlling refining time, performing calcium treatment by using a pure calcium-aluminum wire after the components and the temperature are adjusted, and adjusting soft blowing time to promote floating of inclusions; and (3) continuous casting: protecting and casting the whole process to obtain finished steel, and adjusting the heat preservation process of the tundish;
the method is characterized in that:
the step (1) of adjusting the distribution of the bottom blowing air bricks of the converter and the bottom blowing air supply mode is as follows: 3 bottom blowing elements of the converter are distributed in an eccentric triangle on each side; controlling the bottom blowing flow of the converter in the smelting oxygen step;
the slag remaining and process charging mode in the step (1) is adjusted as follows: after tapping, adopting a primary slag splashing mode, pouring slag to 170 degrees after slag is splashed to dry, and keeping the slag amount to be 2 t; controlling lime in the smelting process;
the adjusting of the terminal carbon drawing gun position and the oxygen supply mode in the step (1) is as follows: the terminal carbon drawing gun position is reduced to 0.8m compared with the normal gun position, and the oxygen supply flow is increased to 30000Nm 3 /h；
The step (1) of determining the end point by combining the flue gas analysis and carrying out gun lifting control comprises the following steps: when the CO content in the flue gas is reduced to below 5 percent at the end point, the gun is lifted, and the carbon at the end point can be stably controlled to be 0.03-0.04 percent.
The calcium treatment process of the pure calcium aluminum wire in the step (2) comprises the following steps: and starting the first furnace, feeding 450-500 meters, and continuously casting 300-350 meters in each furnace.
The tundish heat-preservation process in the step (3) comprises the following steps: firstly adding a low-carbon low-silicon covering agent, then adding a high-performance covering agent, covering asbestos cloth on each baking hole, and keeping the black surfaces of a pouring area and an impact area of the tundish in the pouring process.
Further, the step (1) of controlling the bottom blowing flow of the converter in the oxygen smelting step is specifically that the bottom blowing flow of the converter in the oxygen smelting step is controlled to be 550Nm (Nm) in 0-70 percent 3 The flow rate of bottom blowing of the converter is controlled to be 650Nm at 71-100% in the oxygen smelting step 3 /h。
Further, the step (1) of controlling the lime in the smelting process is specifically that the adding amount of the light burned dolomite is controlled to be 2000-2200 Kg, and the limestone is controlled to be 1500 Kg.
Further, the calcium treatment process of the pure calcium aluminum wire in the step (2) ensures 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.
The invention can realize the end point carbon control method of the low-carbon non-annealed steel converter, and the proportion of the carbon content of the produced non-annealed low-carbon steel refined finished product controlled below 0.055 percent is improved from 80 percent to 99 percent.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a diagram showing the effect of controlling the carbon content of the converter product according to the present invention.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
Examples
A terminal carbon control method of a low-carbon annealing-free steel converter comprises the following steps of (1) step (1) converter: adding a steelmaking raw material into a converter for smelting, fully blowing argon and stirring, adjusting the arrangement of converter bottom-blown air bricks, controlling the bottom-blown flow of the converter according to the converter blowing oxygen step, adjusting a smelting slag-remaining and process feeding mode, and controlling steel tapping; adjusting the distribution of the converter bottom blowing air bricks and the bottom blowing air supply mode, and enabling 3 bottom blowing elements on each side of 6 bottom blowing elements of the converter to be in eccentric triangular distribution; controlling the low blowing flow of the converter in the smelting oxygen step; the bottom blowing flow of the converter with the oxygen smelting step of 0-70 percent is controlled to be 550Nm 3 The flow rate of bottom blowing of the converter is controlled to be 650Nm at 71-100% in the oxygen smelting step 3 H; adjusting a slag retention and process feeding mode, adopting a primary slag splashing mode after tapping is finished, pouring slag to 170 degrees after slag is splashed to dry, and keeping the slag amount to be 2 t; controlling lime in the smelting process; the adding amount of the light-burned dolomite is controlled to be 2000-2200 Kg, and the adding amount of the limestone is controlled to be 1500 Kg; adjusting the terminal carbon drawing gun position and the oxygen supply mode; adjusting the end point carbon drawing gun position and the oxygen supply mode, wherein the end point carbon drawing gun position is reduced to 0.8m compared with the normal gun position, and the oxygen supply flow is increased to 30000Nm 3 H; determining a terminal lance lifting oxygen-closing point by combining the components of the flue gas analysis; when the CO content in the flue gas is reduced to below 5 percent at the end point, the gun is lifted, and the carbon at the end point can be stably controlled to be 0.03-0.04 percent; step (2) LF refining: deoxidizing the slag surface of aluminum particles and ferrosilicon powder, controlling refining time, performing calcium treatment by using a pure calcium-aluminum wire after components and temperature are adjusted, starting a first furnace, feeding 450-500 m, and continuously casting300-350 meters per furnace; ensuring that the calcium-aluminum ratio of the startup 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: protecting and casting the whole process to obtain finished steel, adjusting the heat preservation process of the tundish, adding a low-carbon low-silicon covering agent, then adding a high-performance covering agent, covering asbestos cloth on each baking hole, and keeping the black surface operation of a tundish casting area and an impact area in the casting process.
The invention can realize the end point carbon control method of the low-carbon non-annealed steel converter, the proportion of the carbon content of the produced non-annealed low-carbon steel refined finished product controlled below 0.055 percent is improved from the original 80 percent to 99 percent, the effect is shown in figure 2, and the carbon content of the finished product of the converter (unit: 0.01 percent) is controlled below 0.055 percent.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.
Claims (4)
1. A terminal carbon control method for a low-carbon annealing-free steel converter comprises the following steps of (1) converter: adding a steelmaking raw material into a converter for smelting, fully blowing argon and stirring, adjusting the arrangement of converter bottom-blown air bricks, controlling the bottom-blown flow of the converter according to the converter blowing oxygen step, adjusting a smelting slag retention and process feeding mode, controlling steel tapping, adjusting a terminal point carbon pulling gun position and an oxygen supply mode, analyzing components by combining smoke, and determining a terminal point gun lifting oxygen-closing point; step (2) LF refining: deoxidizing the slag surface of aluminum particles and ferrosilicon powder, controlling refining time, performing calcium treatment by using a pure calcium-aluminum wire after the components and the temperature are adjusted, and adjusting soft blowing time to promote floating of inclusions; and (3) continuous casting: protecting and casting the whole process to obtain finished steel, and adjusting the heat preservation process of the tundish;
the method is characterized in that:
the step (1) of adjusting the distribution of the converter bottom blowing air bricks and the bottom blowing air supply mode is as follows: 3 bottom blowing elements of the converter are distributed in an eccentric triangle on each side; controlling the bottom blowing flow of the converter in the smelting oxygen step;
the slag remaining and process charging mode in the step (1) is adjusted as follows: after tapping, adopting a primary slag splashing mode, pouring slag to 170 degrees after slag is splashed to dry, and keeping the slag amount to be 2 t; controlling lime in the smelting process;
the adjusting of the terminal carbon drawing gun position and the oxygen supply mode in the step (1) is as follows: the terminal carbon drawing gun position is reduced to 0.8m compared with the normal gun position, and the oxygen supply flow is increased to 30000Nm 3 /h；
The step (1) of determining the end point by combining with the flue gas analysis and carrying out gun lifting control comprises the following steps: when the CO content in the flue gas is reduced to below 5 percent at the end point, the gun is lifted, and the carbon at the end point can be stably controlled to be 0.03-0.04 percent;
the calcium treatment process of the pure calcium aluminum wire in the step (2) comprises the following steps: starting a first furnace, feeding 450-500 meters, and continuously casting 300-350 meters in each furnace;
the tundish heat-preservation process in the step (3) comprises the following steps: firstly adding a low-carbon low-silicon covering agent, then adding a high-performance covering agent, covering asbestos cloth on each baking hole, and keeping the black surfaces of a pouring area and an impact area of the tundish in the pouring process.
2. The method for controlling the end point carbon of the low-carbon annealing-free steel converter according to claim 1, characterized by comprising the following steps: the step (1) of controlling the low blowing flow of the converter in the oxygen smelting step is to specifically control the bottom blowing flow of the converter to be 550Nm within 0-70% of the oxygen smelting step 3 H, controlling the flow rate of 71-100% of converter bottom blowing flow in the smelting oxygen step to 650Nm 3 /h。
3. The method for controlling the end point carbon of the low-carbon annealing-free steel converter according to claim 1, characterized by comprising the following steps: the lime used in the smelting process in the step (1) is specifically controlled in such a way that the addition amount of light burned dolomite is controlled to be 2000-2200 Kg, and the addition amount of limestone is controlled to be 1500 Kg.
4. The method for controlling the end point carbon of the low-carbon annealing-free steel converter according to claim 1, characterized by comprising the following steps: in the calcium treatment process of the pure calcium aluminum wire in the step (2), the calcium-aluminum ratio of startup is ensured to be more than or equal to 0.12, and the continuous casting calcium-aluminum ratio is ensured to be more than or equal to 0.09.
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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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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 |
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| 严建新;胡友红;: "SWRCH22A冷镦钢转炉冶炼一次拉碳工艺研究", 金属制品, no. 03 * |
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