CN113927003A - Method for reducing nitrogen increase of tundish molten steel in continuous casting process - Google Patents
Method for reducing nitrogen increase of tundish molten steel in continuous casting process Download PDFInfo
- Publication number
- CN113927003A CN113927003A CN202111212707.5A CN202111212707A CN113927003A CN 113927003 A CN113927003 A CN 113927003A CN 202111212707 A CN202111212707 A CN 202111212707A CN 113927003 A CN113927003 A CN 113927003A
- Authority
- CN
- China
- Prior art keywords
- molten steel
- tundish
- continuous casting
- argon
- casting process
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 48
- 239000010959 steel Substances 0.000 title claims abstract description 48
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000009749 continuous casting Methods 0.000 title claims abstract description 26
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 22
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 43
- 229910052786 argon Inorganic materials 0.000 claims abstract description 20
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 12
- 230000001681 protective effect Effects 0.000 claims abstract description 12
- 238000007664 blowing Methods 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 5
- 239000007789 gas Substances 0.000 claims abstract description 3
- 238000003723 Smelting Methods 0.000 abstract description 4
- 239000002184 metal Substances 0.000 abstract description 2
- 230000007547 defect Effects 0.000 description 5
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/116—Refining the metal
- B22D11/117—Refining the metal by treating with gases
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
The invention relates to the technical field of metal smelting, in particular to steel smelting; the invention aims to solve the technical problem of providing a method for reducing nitrogen increase of molten steel in a tundish in a continuous casting process. The method for reducing nitrogen increase of the molten steel in the tundish in the continuous casting process comprises the following steps: A. blowing argon into the protective tube, wherein the flow rate of the argon is 40L/min-50L/min; B. argon forms positive pressure in the protective tube; C. argon gas is used for blowing the molten steel liquid level in the tundish to a diameter of less than or equal to 100 mm; D. a covering agent is added to the surface of the molten steel in the tundish.
Description
Technical Field
The invention relates to the technical field of metal smelting, in particular to steel smelting.
Background
Nitrogen has a large influence on the properties of non-nitrogen containing steel. In the process of solidifying the continuous casting molten steel into a continuous casting billet, when the content of nitrogen in the molten steel is more than or equal to 50ppm, the continuous casting molten steel is easily combined with microalloy elements such as [ Al ], [ V ], [ Nb ], [ Ti ] and the like in the steel, formed combination substances such as [ AlN ], [ VN ], [ NbN ], [ TiN ] and the like are separated out at a grain boundary, the strength of the grain boundary is weakened, the microcrack defect of the continuous casting billet along the grain boundary is easily induced, and the microcrack defect of the continuous casting billet along the grain boundary is expressed as a line defect on the surface of a plate coil in a rolling process, so that serious quality degradation loss is caused.
From a converter to an LF furnace or an RH station, the nitrogen content in molten steel is stabilized at 27 ppm-35 ppm, but the nitrogen content of the molten steel of a continuous casting tundish fluctuates greatly within the range of 38 ppm-62 ppm, the nitrogen is increased by 11 ppm-27 ppm in the continuous casting process, and the proportion of more than or equal to 50ppm is up to 52%.
The deep analysis of the nitrogen increase reason in the continuous casting process discovers that the abnormal nitrogen increase in the continuous casting process is related to the poor protective casting effect of the molten steel in the continuous casting process, and nitrogen in the air enters the molten steel in the tundish. In order to reduce nitrogen increase of tundish molten steel in the continuous casting process, the argon blowing flow control of a protective tube in the continuous casting process and the tundish covering agent consumption are optimally controlled.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for reducing nitrogen increase of molten steel in a tundish in a continuous casting process.
The technical scheme adopted by the invention for solving the technical problems is as follows: the method for reducing nitrogen increase of the molten steel in the tundish in the continuous casting process comprises the following steps:
A. blowing argon into the protective tube, wherein the flow rate of the argon is 40L/min-50L/min;
B. argon forms positive pressure in the protective tube;
C. argon gas is used for blowing the molten steel liquid level in the tundish to a diameter of less than or equal to 100 mm;
D. a covering agent is added to the surface of the molten steel in the tundish.
Further, for step D, the covering agent is added in an amount of 0.2kg to 0.3kg per ton of steel.
Further, the thickness of the covering agent is 40mm to 90 mm.
The invention has the beneficial effects that: the nitrogen increasing amount of the molten steel in the process that the protective pipe flows to the tundish is reduced by the argon, positive pressure is formed in the protective pipe by the argon to prevent air from being sucked into the protective pipe and entering the molten steel, the molten steel liquid level in the tundish is blown by the argon to be less than or equal to 100mm in diameter, and the molten steel in the tundish is prevented from directly contacting with the air. After the detection of the tundish molten steel, the tundish molten steel increases nitrogen by 3ppm to 10ppm in the continuous casting process, and is greatly reduced compared with the original 11ppm to 27ppm, the proportion that the nitrogen content of the tundish molten steel is less than 50ppm reaches 100 percent, the continuous casting billet micro-crack defect is effectively controlled, and the corresponding coil surface line defect is also effectively controlled.
Detailed Description
The continuous casting production process flow of the steel slab comprises the following steps: the invention relates to a process in which the flow range is a part in continuous casting, namely molten steel enters a tundish part from a molten steel tank through a protection pipe.
The method for reducing nitrogen increase of the molten steel in the tundish in the continuous casting process comprises the following steps:
A. argon is blown into the protection tube through an argon blowing tube communicated with the protection tube, the flow of the argon is 40L/min-50L/min, and the argon can be replaced by other suitable inert gases;
B. when the flow of the argon is minimum, positive pressure is formed in the protective tube;
C. when the flow of argon is maximum, the diameter of the molten steel liquid level in the tundish blown by the argon is less than or equal to 100 mm;
D. adding a molten steel covering agent for heat preservation and isolation to the surface of the molten steel in the tundish.
And D, giving a recommended value range of the using amount of the covering agent, wherein for the step D, the adding amount of the covering agent is 0.2 kg-0.3 kg per ton of steel.
The thickness of the covering agent is recommended to be 40mm to 90 mm. The method ensures the full coverage of the surface of the molten steel in the tundish, avoids the direct contact of the molten steel and air, and does not influence the temperature measurement and sampling operation of a steel pouring operator on the molten steel in the tundish.
Claims (3)
1. The method for reducing nitrogen increase of the molten steel in the tundish in the continuous casting process is characterized by comprising the following steps of:
A. blowing argon into the protective tube, wherein the flow rate of the argon is 40L/min-50L/min;
B. argon forms positive pressure in the protective tube;
C. argon gas is used for blowing the molten steel liquid level in the tundish to a diameter of less than or equal to 100 mm;
D. a covering agent is added to the surface of the molten steel in the tundish.
2. The method of reducing nitrogen increase in a tundish molten steel in a continuous casting process according to claim 1, wherein: for step D, the addition of the covering agent is 0.2kg to 0.3kg per ton of steel.
3. The method of reducing nitrogen increase in a tundish molten steel in a continuous casting process according to claim 2, wherein: the thickness of the covering agent is 40 mm-90 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111212707.5A CN113927003A (en) | 2021-10-18 | 2021-10-18 | Method for reducing nitrogen increase of tundish molten steel in continuous casting process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111212707.5A CN113927003A (en) | 2021-10-18 | 2021-10-18 | Method for reducing nitrogen increase of tundish molten steel in continuous casting process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113927003A true CN113927003A (en) | 2022-01-14 |
Family
ID=79280143
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111212707.5A Pending CN113927003A (en) | 2021-10-18 | 2021-10-18 | Method for reducing nitrogen increase of tundish molten steel in continuous casting process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113927003A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004066335A (en) * | 2002-08-09 | 2004-03-04 | Jfe Steel Kk | Method for continuously casting steel |
| CN103667581A (en) * | 2013-11-22 | 2014-03-26 | 首钢水城钢铁（集团）有限责任公司 | Low-nitrogen SWR82B steel smelting method |
| CN108273971A (en) * | 2018-03-05 | 2018-07-13 | 首钢京唐钢铁联合有限责任公司 | A method of reducing casting process molten steel nitrogen increased amount |
| CN109382506A (en) * | 2018-11-20 | 2019-02-26 | 山东钢铁股份有限公司 | A kind of method of molten steel nitrogen increased amount in reduction continuous casting process |
| CN111004886A (en) * | 2019-11-25 | 2020-04-14 | 湖南华菱涟源钢铁有限公司 | Smelting method for reducing unit consumption of molten iron |
| CN111496238A (en) * | 2020-05-21 | 2020-08-07 | 宝武集团马钢轨交材料科技有限公司 | Continuous casting tundish micro-positive pressure argon sealing casting device and control system and method |
| CN112981038A (en) * | 2021-04-22 | 2021-06-18 | 北京科技大学 | Method for reducing nitrogen content in steel to obtain low-nitrogen steel in electric furnace steelmaking process |
-
2021
- 2021-10-18 CN CN202111212707.5A patent/CN113927003A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004066335A (en) * | 2002-08-09 | 2004-03-04 | Jfe Steel Kk | Method for continuously casting steel |
| CN103667581A (en) * | 2013-11-22 | 2014-03-26 | 首钢水城钢铁（集团）有限责任公司 | Low-nitrogen SWR82B steel smelting method |
| CN108273971A (en) * | 2018-03-05 | 2018-07-13 | 首钢京唐钢铁联合有限责任公司 | A method of reducing casting process molten steel nitrogen increased amount |
| CN109382506A (en) * | 2018-11-20 | 2019-02-26 | 山东钢铁股份有限公司 | A kind of method of molten steel nitrogen increased amount in reduction continuous casting process |
| CN111004886A (en) * | 2019-11-25 | 2020-04-14 | 湖南华菱涟源钢铁有限公司 | Smelting method for reducing unit consumption of molten iron |
| CN111496238A (en) * | 2020-05-21 | 2020-08-07 | 宝武集团马钢轨交材料科技有限公司 | Continuous casting tundish micro-positive pressure argon sealing casting device and control system and method |
| CN112981038A (en) * | 2021-04-22 | 2021-06-18 | 北京科技大学 | Method for reducing nitrogen content in steel to obtain low-nitrogen steel in electric furnace steelmaking process |
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|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20220114 |