CN114350893B - Online cleaning method for accumulated slag on furnace cover of LF (ladle furnace) refining furnace - Google Patents
Online cleaning method for accumulated slag on furnace cover of LF (ladle furnace) refining furnace Download PDFInfo
- Publication number
- CN114350893B CN114350893B CN202210002681.XA CN202210002681A CN114350893B CN 114350893 B CN114350893 B CN 114350893B CN 202210002681 A CN202210002681 A CN 202210002681A CN 114350893 B CN114350893 B CN 114350893B
- Authority
- CN
- China
- Prior art keywords
- furnace
- furnace cover
- refining
- slag
- molten steel
- 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.)
- Active
Links
Classifications
-
- 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
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
An online cleaning method for accumulated slag on a furnace cover of an LF refining furnace comprises the following steps: tapping after smelting in a converter; LF furnace refining, operation and control at this stage: lowering the furnace cover of the LF refining furnace to a position which is less than or equal to 50mm away from the mouth of the molten steel tank; and (3) electrically heating the molten steel under the protection of argon: when the temperature is not lower than 1580 ℃, the flow of argon is reduced to not more than 50NL/min, and the arc current is reduced to 24000-28000A; when the heating area is white, continuing to heat for 2-6 min and stopping heating; C. adjusting the position of the electrode; the following steps are performed. The invention can lead the accumulated slag on the furnace cover of the LF refining furnace to be manually stopped and cleaned four times per month, and the cleaning for each time needs about 3 hours to realize the on-line treatment, thereby improving the production efficiency by at least 1.5 percent; when the steel grade for smelting requires low carbon, low silicon and low sulfur, the problem of changing steel into steel with excessive components caused by furnace cover slag can be solved; when different steel grades are smelted, the furnace cover switching of the LF refining furnace is accelerated, and time is won for smelting the next furnace.
Description
Technical Field
The invention belongs to the field of smelting of molten steel, and particularly relates to a method for automatically cleaning accumulated slag on a furnace cover in a refining process by using an LF (ladle furnace).
Background
Adjusting the temperature of molten steel is one of the main tasks of an LF furnace. The LF furnace enables electric arcs to be buried in a slag layer in the heating process by making proper slag and selecting matched arc flow arc voltage, so that high thermal efficiency is obtained. The voltage and current of the electric arc can be well controlled electrically, so that the control precision of the temperature rising speed is higher than that of a chemical heating method. At present, an LF refining furnace is necessary steelmaking process equipment for domestic steel mills.
The accumulated slag sources of the furnace cover of the LF furnace are as follows: the impact of the electric arc on the steel slag during heating, and dust generated by the added materials, which are accumulated on the furnace cover for a long time to form furnace cover slag deposit. The LF process molten steel is heated by the high temperature of the electric arc, the electric arc is a high-temperature and high-speed gas jet flow, the molten pool is impacted, a pit is formed at the impact point, the pit depth is related to arc pressure and arc flow, when the arc flow is in the range of 20-85KA, the pit depth/arc flow is averagely 3mm/KA, the current ladle furnace operation arc flow is in the range of 20-28.8KA, the impact pit depth is 60-90mm, and when the electrode is used for heating, a naked molten steel surface can appear at the pit. When the amount of the slag is less, particularly the slag is agglomerated or relatively grown at the early stage of refining, the electric arc directly strikes the molten steel to send out crack noise, and the molten steel and the slag are ejected to a furnace cover. Meanwhile, in the heating process of the LF furnace, volatile matters are decomposed from the molten slag under the action of a strong electric arc, impurities are brought in when alloy, a carburant and a slagging material are added, and dust is generated by violent turnover of the molten steel when calcium wires are fed. The substances are gradually adhered to the furnace cover in the continuous operation process of the LF furnace, so that furnace cover slag is gradually thickened.
Slag accumulation damage of a furnace cover:
1) When the accumulated slag reaches a certain amount, the self-gravity is close to or greater than the lifting force, the furnace cover is lifted slowly or loses the lifting function, and the production stop of the LF furnace can be caused;
2) The slag accumulated on the furnace cover has complex composition, may contain harmful impurities such as steel, desulfurized slag and the like, and can increase the content of elements such as C, S, si and the like in the smelting molten steel, thereby causing the components to exceed the standard;
3) The risk of furnace cover slag accumulation collapsing at any time exists, and safety risk exists for related operators.
At present, two methods are mainly adopted for disposing the slag accumulated on the furnace cover, namely: firstly, arc pressing flow is adjusted, and slag is formed and arc is submerged. The cleaning frequency and the slag accumulation speed of the furnace cover can only be reduced, but the problem that the slag accumulation on the furnace cover still needs manual shutdown cleaning still exists; secondly, the furnace cover is intermittently shut down to manually clean accumulated slag, hot slag is beaten and cooled after the machine is shut down, the accumulated slag is beaten by tools such as an air pick and the like, slag blocks falling on a slag channel are conveyed away, and each cleaning not only needs 2-3 hours to cause low production efficiency, but also has high labor intensity and relatively large damage to the furnace cover.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides the online self-cleaning method for the accumulated slag of the furnace cover of the LF (ladle furnace) refining furnace, which has the advantages that the production is not influenced, the accumulated slag of the furnace cover of the LF furnace can be automatically cleaned online, the production efficiency is improved by at least 1.5 percent, and the accumulated slag of the furnace cover of the LF furnace can be cleaned without manually cleaning the accumulated slag.
The measures for realizing the aim are as follows:
an LF refining furnace cover slag deposit online cleaning method is characterized by comprising the following steps: the method comprises the following steps:
1) Tapping after smelting in a converter, controlling the distance between the liquid steel surface and a molten steel tank opening to be 300-600 mm, and controlling the thickness of slag on the molten steel tank opening not to exceed 50mm;
2) And (3) carrying out LF furnace refining, and operating and controlling the refining at the stage according to the following steps:
A. lowering the furnace cover of the LF refining furnace to a position which is less than or equal to 50mm away from the mouth of the molten steel tank;
B. under the protection of argon, the molten steel is electrically heated, and the flow rate of the argon is controlled to be 150-250NL/min: when the temperature is not lower than 1580 ℃, the following parameters are adjusted:
reducing the argon flow to be not more than 50NL/min, and reducing the arc current to 24000-28000A;
when the heating area is white, continuing to heat for 2-6 min and then stopping heating;
C. adjusting the position of the electrode to ensure that the distance between the lower end surface of the electrode and the liquid level of the molten steel is 200-500 mm, and the reddened area of the electrode is not exposed out of the furnace cover, so that the phenomenon of slag deposition on the furnace cover is kept to be free from dripping;
3) And (4) performing the next procedure, when the residual thickness of the accumulated slag on the furnace cover is more than 50mm, heating by using a starting electrode, and further melting the accumulated slag on the furnace cover until the residual thickness of the accumulated slag on the furnace cover is less than 50mm after white light appears in a heating zone, and performing the next procedure.
Preferably: after heating to 1590 deg.C, parameter adjustment was performed.
Preferably: when the temperature is higher than 1580 ℃, the flow of argon is regulated to be not more than 30NL/min, and the arc current is reduced to 24000-27500A.
Action and mechanism of the main process in the invention
According to the invention, the impact area generates high temperature (2400-2600K) when the electrode of the LF furnace is heated, the heat exchange efficiency between slag and steel is reduced during electric arc heating, the heat is stopped to flow in an area near the upper surface of molten steel, the accumulated slag on the furnace cover is melted by using the high heat near the heating area and drops to the molten steel tank or a slag channel, and the purpose of cleaning the accumulated slag on the furnace cover without stopping the furnace is achieved.
The reason why the distance between the molten steel surface and the upper edge of the molten steel tank is controlled to be 300-600 mm is that when the distance between the molten steel surface and the upper edge of the molten steel tank is more than 600mm, heat is not enough to be transferred to the furnace cover, but erosion is caused to refractory materials of the molten steel tank, and the lower limit of 300mm is the safety requirement of molten steel heating.
The invention controls the thickness of the slag on the edge of the molten steel tank to be not more than 50mm, and aims to ensure that the distance between the furnace cover of the LF refining furnace and the upper edge of the molten steel tank can be controlled within 50mm after the furnace cover is lowered, enhance the sealing property of the furnace cover, reduce the cooling of air on high-temperature gas during dust removal and air suction, and keep higher temperature between the molten steel surface and the furnace cover all the time.
When the temperature is higher than 1580 ℃, the flow of argon is reduced to not more than 50NL/min, and the arc current is reduced to 24000-28000A; when the heating area is white, continuing to heat for 2-6 min and stopping heating; the reason is that the higher the temperature of the molten steel is, the more beneficial the melting of the accumulated slag of the furnace cover is, the highest temperature of all steel grades needs to reach 1580 ℃ during normal production, namely, the operation of furnace cover slagging is carried out at the highest temperature in the refining process. The reason that the higher the area temperature is, the more dazzling the emitted light is, the white light is emitted indicates that the local temperature reaches the high temperature stage; the time of the stage lasts for 2-6 min to ensure the melting of the slag deposit on the furnace cover of the LF refining furnace, but if the time of the period is too long, the refractory and the furnace cover can be damaged, and production accidents can be caused.
After the heating is finished, the electrode red area is not exposed out of the furnace cover, because a large amount of waste heat still exists in the electrode after the heating is finished, in order to fully utilize the heat, the electrode is slightly lifted, and the electrode red end is enabled to be at the same horizontal plane with the accumulated slag of the furnace cover, so that the molten slag is continuously dropped.
Compared with the prior art, the invention has the advantages that:
1) The slag accumulated on the furnace cover of the LF refining furnace is manually stopped and cleaned four times per month originally, and the cleaning for each time needs about 3 hours to realize online treatment, so that the production is continuously carried out, and the production efficiency is improved by at least 1.5%;
2) When the steel grade to be smelted is required to be low-carbon, low-silicon and low-sulfur, the problem of steel modification due to excessive components caused by furnace cover slag is reduced due to the obvious reduction of slag accumulation on a furnace cover of the LF refining furnace, and the prior art has the modification amount of about 300 tons per year;
3) When different steel grades are smelted, the furnace cover switching of the LF refining furnace is accelerated, and time is won for smelting the next furnace.
Detailed Description
The present invention is described in detail below:
the embodiments of the invention are produced according to the following steps:
1) Tapping after smelting in a converter, controlling the distance between the liquid level of molten steel and the mouth of a molten steel tank to be 300-600 mm, and controlling the mouth of the molten steel tank
The thickness of the upper slag is not more than 50mm;
2) And (3) carrying out LF furnace refining, and operating and controlling the refining at the stage according to the following steps:
A. lowering the furnace cover of the LF refining furnace to a position which is less than or equal to 50mm away from the mouth of the molten steel tank;
B. under the protection of argon, the molten steel is electrically heated, and the flow rate of the argon is controlled to be 150-250NL/min: when the temperature is not lower than 1580 ℃, the following parameters are adjusted:
reducing the argon flow to be not more than 50NL/min, and reducing the arc current to 24000-28000A;
when the heating area is white, continuing to heat for 2-6 min and stopping heating;
C. adjusting the position of the electrode to ensure that the distance between the lower end surface of the electrode and the liquid level of the molten steel is 200-500 mm, and the reddened area of the electrode is not exposed out of the furnace cover, so that the phenomenon of slag deposition on the furnace cover is kept to be free from dripping;
3) And (4) performing the next procedure, when the residual thickness of the accumulated slag on the furnace cover is more than 50mm, heating by using a starting electrode, and further melting the accumulated slag on the furnace cover until the residual thickness of the accumulated slag on the furnace cover is less than 50mm after white light appears in a heating zone, and performing the next procedure.
Table 1 is a list of process parameters for each example of the present invention at step 1);
table 2 is a list of process parameters in step 2) for each example of the present invention;
table 3 shows the effects of the embodiments of the present invention.
TABLE 1 List of the process parameters for the inventive examples and comparative examples in step 1)
TABLE 2 list of process parameters for the inventive examples and comparative examples in step 2)
TABLE 2
TABLE 3 List of the effects of the examples of the present invention and comparative examples
It should be noted that: the steel grades listed in the embodiments of the invention are all in one-to-one correspondence with the process.
The present embodiments are merely preferred examples, and are not intended to limit the scope of the present invention.
Claims (3)
1. An online cleaning method for accumulated slag on a furnace cover of an LF refining furnace is characterized by comprising the following steps: the method comprises the following steps:
1) Tapping after smelting in a converter, controlling the distance between the liquid steel surface and a molten steel tank opening to be 300-600 mm, and controlling the thickness of slag on the molten steel tank opening not to exceed 50mm;
2) And (3) carrying out LF furnace refining, and operating and controlling the refining at the stage according to the following steps:
A. lowering the furnace cover of the LF refining furnace to a position which is less than or equal to 50mm away from the mouth of the molten steel tank;
B. under the protection of argon, the molten steel is electrically heated, and the flow rate of the argon is controlled to be 150-250NL/min: when the temperature is not lower than 1580 ℃, the following parameters are adjusted:
reducing the argon flow to be not more than 50NL/min, and reducing the arc current to 24000-28000A;
when the heating area is white, continuing to heat for 2-6 min and stopping heating;
C. adjusting the position of the electrode to ensure that the distance between the lower end surface of the electrode and the liquid level of the molten steel is 200-500 mm, and the reddened area of the electrode is not exposed out of the furnace cover, so that the phenomenon of residue deposition on the furnace cover is kept to be free from dripping;
3) And (4) performing the next procedure, when the residual thickness of the accumulated slag on the furnace cover is more than 50mm, heating by using a starting electrode, and further melting the accumulated slag on the furnace cover until the residual thickness of the accumulated slag on the furnace cover is less than 50mm after white light appears in a heating zone, and performing the next procedure.
2. The on-line cleaning method for accumulated slag on the furnace cover of the LF refining furnace, as recited in claim 1, is characterized in that: after heating to 1590 deg.C, parameter adjustment was performed.
3. The on-line cleaning method for accumulated slag on the furnace cover of the LF refining furnace, as recited in claim 1, is characterized in that: when the temperature is higher than 1580 ℃, the flow of argon is adjusted to be not more than 30NL/min, and the arc current is reduced to 24000-27500A.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210002681.XA CN114350893B (en) | 2022-01-04 | 2022-01-04 | Online cleaning method for accumulated slag on furnace cover of LF (ladle furnace) refining furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210002681.XA CN114350893B (en) | 2022-01-04 | 2022-01-04 | Online cleaning method for accumulated slag on furnace cover of LF (ladle furnace) refining furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114350893A CN114350893A (en) | 2022-04-15 |
| CN114350893B true CN114350893B (en) | 2022-11-11 |
Family
ID=81105172
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210002681.XA Active CN114350893B (en) | 2022-01-04 | 2022-01-04 | Online cleaning method for accumulated slag on furnace cover of LF (ladle furnace) refining furnace |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114350893B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1153677A (en) * | 1956-05-18 | 1958-03-20 | Handelsgesellschaft Ind G M B | Welding process of gray cast iron or hematite cast iron objects |
| JPS60200949A (en) * | 1984-03-23 | 1985-10-11 | Sumitomo Metal Ind Ltd | Production of high-carbon ferromanganese |
| JPH1072615A (en) * | 1996-08-30 | 1998-03-17 | Nippon Carbon Co Ltd | Method for refining molten metal in ladle and apparatus therefor |
| CN102559995A (en) * | 2012-02-29 | 2012-07-11 | 攀钢集团西昌钢钒有限公司 | Water-cooled furnace lid for refined-smelting ladle furnace, and slag removal method of dust-proof flue of water-cooled furnace lid |
| CN105817613A (en) * | 2016-06-06 | 2016-08-03 | 山东钢铁股份有限公司 | Anchor for cleaning accumulated slag at steel ladle hole |
| CN210922207U (en) * | 2019-08-05 | 2020-07-03 | 江阴兴澄特种钢铁有限公司 | Water-cooled furnace cover of refining furnace |
-
2022
- 2022-01-04 CN CN202210002681.XA patent/CN114350893B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1153677A (en) * | 1956-05-18 | 1958-03-20 | Handelsgesellschaft Ind G M B | Welding process of gray cast iron or hematite cast iron objects |
| JPS60200949A (en) * | 1984-03-23 | 1985-10-11 | Sumitomo Metal Ind Ltd | Production of high-carbon ferromanganese |
| JPH1072615A (en) * | 1996-08-30 | 1998-03-17 | Nippon Carbon Co Ltd | Method for refining molten metal in ladle and apparatus therefor |
| CN102559995A (en) * | 2012-02-29 | 2012-07-11 | 攀钢集团西昌钢钒有限公司 | Water-cooled furnace lid for refined-smelting ladle furnace, and slag removal method of dust-proof flue of water-cooled furnace lid |
| CN105817613A (en) * | 2016-06-06 | 2016-08-03 | 山东钢铁股份有限公司 | Anchor for cleaning accumulated slag at steel ladle hole |
| CN210922207U (en) * | 2019-08-05 | 2020-07-03 | 江阴兴澄特种钢铁有限公司 | Water-cooled furnace cover of refining furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114350893A (en) | 2022-04-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112322837A (en) | Smelting process for efficient slagging and desulfurization of LF (ladle furnace) aluminum killed steel | |
| CN1686666A (en) | Production method of large high chromium steel cold roll blank | |
| US20180340734A1 (en) | Electric arc furnace and method of operating same | |
| CN109423537A (en) | A kind of method of the quick cold steel of removal RH vacuum chamber | |
| CN107164639A (en) | A kind of electron beam covers the method that formula solidification technology prepares high temperature alloy | |
| WO2022001874A1 (en) | Slag-splashing fettling method | |
| CN102220634A (en) | Method to raise production efficiency of czochralski silicon mono-crystal | |
| CN114350893B (en) | Online cleaning method for accumulated slag on furnace cover of LF (ladle furnace) refining furnace | |
| CN104846146A (en) | Control method for preventing nitrogen increasing in LF refining treatment | |
| KR20040056706A (en) | A method for refining with high purity of stainless steel | |
| CN102051439B (en) | Method for smelting high aluminium steel | |
| CN112921149A (en) | Steel-making production control method of ultra-low sulfur steel | |
| CN108660290A (en) | A kind of compound ar blowing refining device and method in Medium frequency induction furnace roof bottom | |
| CN207619447U (en) | A kind of recoverable shaped steel refining slag hearth | |
| CN108728606B (en) | Production process of cold roll steel electroslag blank | |
| KR101210354B1 (en) | MANUFACTURING METHOD OF LOW CARBON SiMn BY LADLE FURNACE | |
| US20240191315A1 (en) | Electric furnace and steelmaking method | |
| EP4303327A1 (en) | Electric furnace and steelmaking method | |
| CN115109886B (en) | Heat preservation method for long-time shutdown of converter | |
| CN110144431A (en) | A kind of calcium treating method for the refining of LF furnace | |
| CN115820956B (en) | Sectional erosion control method for blast furnace hearth | |
| CN104818365B (en) | Steelmaking method capable of enhancing calcium/sulfur ratio in steel | |
| CN109028995A (en) | A method of processing Isa furnace feed opening dross | |
| CN112746180B (en) | Method for promoting electron beam refining nickel-based high-temperature alloy desulfurization through slagging | |
| CN110408742B (en) | Electrochemical refining device and method for preparing ultrapure steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |