CN109022681B - Method for reducing blockage of submerged nozzle through calcium-aluminum-iron alloy treatment - Google Patents
Method for reducing blockage of submerged nozzle through calcium-aluminum-iron alloy treatment Download PDFInfo
- Publication number
- CN109022681B CN109022681B CN201810805313.2A CN201810805313A CN109022681B CN 109022681 B CN109022681 B CN 109022681B CN 201810805313 A CN201810805313 A CN 201810805313A CN 109022681 B CN109022681 B CN 109022681B
- Authority
- CN
- China
- Prior art keywords
- calcium
- aluminum
- iron
- iron alloy
- 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
Images
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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- 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
-
- 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
-
- 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
- C21C7/068—Decarburising
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a method for reducing the blockage of an immersion nozzle through calcium-aluminum-iron alloy treatment, and belongs to the technical field of steel-making refining. In the RH refining process, forced decarburization or natural decarburization is adopted according to the station entering condition, the aluminum block is used for complete deoxidation after decarburization, the content of Alt in steel is adjusted according to the target by using calcium-aluminum-iron after the aluminum block is added for 3min, other alloys and the calcium-aluminum-iron are simultaneously added from a vacuum hopper, the vacuum circulation treatment of the molten steel is continuously carried out under vacuum, and the uniform distribution of calcium in the molten steel is ensured. The low-melting-point inclusion is formed by the reaction of calcium in the alloy and alumina inclusion in molten steel, so that the accumulation of the alumina inclusion at a water gap is reduced, the occurrence of water gap blockage in the casting process is reduced, and the quality of a casting blank is improved. The invention has higher process application value, simple and convenient field operation and can obviously reduce the occurrence of water gap blockage.
Description
Technical Field
The invention relates to a method for reducing the blockage of an immersion nozzle through calcium-aluminum-iron alloy treatment, and belongs to the technical field of steel-making refining.
Background
In-casting ultra-low carbon steel (C)<0.0030%) in the RH refining process, aluminum particles are mostly adopted to deoxidize the steel, and the aluminum particles and the oxygen in the molten steel generate Al2O3Although small-particle inclusions are easy to collide, polymerize and grow to float upwards and be removed in the later-stage calming and casting process, a part of the inclusions still exist in molten steel and are easy to gather at the outlet of a submerged nozzle of a crystallizer to cause the phenomenon of nozzle blockage. The water gap blockage can cause the asymmetric flow of a flow field of molten steel in the crystallizer, so that the liquid level fluctuation is influenced, the slag entrapment defect is caused, and the quality of a casting blank is further influenced. When the water gap is blocked, only the operation of changing the water gap can be adopted, the water gap is operated to reduce the pulling speed, and an operator installs a newly baked water gap and then raises the pulling speed to a normal level, thereby seriously affecting the production efficiency.
Disclosure of Invention
Aiming at Al generated by aluminum particles and oxygen in molten steel in the RH refining process2O3The invention provides a method for reducing the blockage of a submerged nozzle by calcium-aluminum-iron alloy treatment, aiming at solving the problems caused by impurities2O3The inclusions are denatured to generate calcium aluminate, so that calcium in molten steel is ensured to be uniformly distributed while the calcium aluminate is not easy to gather, thereby reducing the occurrence of blockage of a submerged nozzle of a crystallizer and improving the quality of a casting blank.
The invention relates to a method for reducing the blockage of a submerged nozzle by calcium-aluminum-iron alloy treatment, which comprises the following steps:
(1) controlling the oxygen content and the temperature of the converter endpoint;
(2) modifying slag during tapping;
(3) after the molten steel enters RH, rapidly vacuumizing for decarburization;
(4) adding aluminum to deoxidize, wherein the adding amount of the aluminum ensures that Als in the deoxidized steel is 0.010-0.018%;
(5) after the deoxidation is finished, pure circulation is carried out for 3 minutes;
(6) simultaneously adding calcium, aluminum and iron and other alloys, and adjusting the Alt content in the steel to be within the range of 0.035-0.040% when the process is finished;
(7) then pure circulation is carried out for 6-9 minutes;
(8) breaking vacuum and finishing refining.
According to the method for reducing the blockage of the immersion nozzle by the calcium-aluminum-iron alloy treatment, the oxygen content in the step (1) is controlled to be 500-700ppm, and the temperature is 1670-1685 ℃.
According to the method for reducing the blockage of the submerged nozzle by the calcium-aluminum-iron alloy treatment, the slag is modified by adding slag balls and small-particle lime when tapping in the step (2).
The method for reducing the blockage of the submerged nozzle by the calcium-aluminum-iron alloy treatment, disclosed by the invention, is characterized in that the decarburization time in the step (3) is controlled to be 14-16 min.
In the RH refining process, forced decarburization or natural decarburization can be adopted according to the station entering condition, when [ O ] is less than or equal to [ C ] multiplied by 1.5+100, oxygen is blown for forced decarburization, otherwise, natural decarburization is carried out.
The method for reducing the blockage of a submerged nozzle by calcium-aluminum-iron alloy treatment according to the invention, wherein the aluminum is added in the step (4) in such an amount that the Als in the deoxidized steel is preferably 0.015%.
The term "calcium aluminum iron" according to the present invention is a linear alloy of Ca powder wrapped by sheet iron, and table 1 refers to important chemical components of calcium aluminum iron, as shown below.
TABLE 1 calcium aluminum iron important ingredient reference (%)
| Al | Ca | Others |
| 55-65 | 8-12 | / |
According to the method for reducing the blockage of the submerged nozzle through the calcium-aluminum-iron alloy treatment, the adding amount of the calcium-aluminum-iron in the step (6) is calculated according to the target Alt content and the alloy content of the calcium-aluminum-iron shown in the table 1.
According to the method for reducing the blockage of the submerged nozzle through the calcium-aluminum-iron alloy treatment, in the step (6), according to different types of smelting steel, other alloys are added, and the other alloys can be micro-carbon ferromanganese, ferrophosphorus and the like.
After aluminum particles in RH are deoxidized, calcium-aluminum-iron alloy is added into a vacuum hopper for treatment, calcium is uniformly distributed by means of the circulating process of molten steel, so that the Ca content of the molten steel in a tundish is controlled to be 5-10 ppm, the castability of the molten steel is good, the incidence rate of water gap blockage is reduced, and the quality of casting blanks is improved
Drawings
FIG. 1 is a casting curve after treatment with a calcium-aluminum-iron alloy.
FIG. 2 is a comparison of the nozzle before and after the treatment of the calcium-aluminum-iron alloy. Wherein, the left figure is a casting finishing nozzle without calcium-aluminum-iron treatment; the right drawing shows the end-of-casting nozzle where the calcium-aluminum-iron treatment is performed.
FIG. 3 is Zeiss scanning analysis electron microscopic spectrum of main inclusion before and after calcium-aluminum-iron alloy treatment. Wherein, the left figure is a Zeiss scanning analysis electron microscope spectrogram without calcium, aluminum and iron treatment; the right figure shows Zeiss scanning analysis electron micrographs of calcium, aluminum and iron treated samples.
Examples
In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.
Comparative example 1
Smelting an ultra-low carbon SDC04 steel for a certain heat, wherein the tapping temperature of a converter is 1683 ℃, the end point oxygen content is 530ppm, aluminum slag balls and small white ash are added during tapping for slag modification, the RH arrival temperature is 1638 ℃, RH refining is carried out for natural decarburization, the decarburization time is 15min, complete deoxidation is carried out by using an aluminum block, Als in the steel is 0.015% after deoxidation, Fe-Ti alloy is added after 3min of the aluminum block, RH pure circulation is broken for 8min, the Ca content of a tundish molten steel is detected to be 0ppm, continuous casting is carried out in a carbon steel ultra-low 7 furnace, the section is 237mm multiplied by 1800mm, the casting speed is 1.0m/min, ultra-low carbon steel protective slag is adopted, the superheat degree is controlled to be 25-40 ℃, a tundish adopts a high-alkalinity covering agent, three-way argon protection, casting protection, casting protection and other protection measures such as opening protection casting are adopted, the stopper rod position rises in the whole casting process, a submerged nozzle is observed, and the thickness, a tendency to clog has developed.
Example 1
Smelting an ultra-low carbon SDC04 steel for a certain heat, wherein the tapping temperature of a converter is 1679 ℃, the end point oxygen content is 527ppm, aluminum slag balls and small white ash are added during tapping for slag modification, the RH arrival temperature is 1635 ℃, RH refining is carried out for natural decarburization, the decarburization time is 15min, an aluminum block is used for complete deoxidation, Als in the steel after deoxidation is 0.015%, the Alt content in the steel is adjusted to be 0.042% according to the target by using calcium-aluminum-iron after the aluminum block is added for 3min, meanwhile, Fe-Ti alloy is added, RH pure cycle is broken in 8min, the Ca content detected by molten steel in a tundish is controlled to be 7ppm, continuous casting is carried out in a 7-furnace for casting carbon steel, the section is 237mm multiplied by 1800mm, the drawing speed is 1.0m/min, carbon steel protective slag is adopted, the superheat degree is controlled to be 25-40 ℃, a high covering agent is adopted in the tundish, three-way of protective casting measures such as argon protection, casting protection and casting protection are adopted, the casting protection is opened, the observation of changing the lower nozzle can observe that the submerged nozzle is not obviously blocked, and the method can be found to be simple and convenient to operate, has obvious effect and improves the quality of casting blanks.
Immersion nozzle contrast analysis
Figure 2 compares the end of casting nozzle without calcium aluminide treatment (left) with calcium aluminide treatment (right). As can be seen in the figure, the inner wall of the water gap is blocked to a larger thickness after the casting without the calcium-aluminum-iron treatment, while the inner wall of the water gap is not blocked to a serious thickness after the casting with the calcium-aluminum-iron treatment, so that the effect is obvious.
Morphology analysis of inclusions in molten steel
FIG. 3 is a graph comparing the morphology of inclusions in molten steel without calcium-aluminum-iron treatment (left) and with calcium-aluminum-iron treatment (right). As shown in the figure, most of the shape types of the inclusions in the molten steel are angular Al when the molten steel is not treated by the calcium-aluminum-iron alloy2O3Type inclusions; most of the shape types of the inclusions in the molten steel treated by the calcium-aluminum-iron alloy are Al2O3CaO composite type inclusions, the morphology of which appears spherical. It can be seen that the Al in the shape of an edge is treated by the calcium-aluminum-iron alloy2O3The type plays a role in denaturation, and the blockage of the water gap can be reduced.
According to the method for reducing the blockage of the submerged nozzle through the calcium-aluminum-iron alloy treatment, disclosed by the invention, the Al content of the Al subjected to aluminum particle deoxidation in RH refining is reduced2O3The condition that similar impurities are accumulated at a water gap to cause blockage is avoided, the influence of calcium treatment on secondary oxidation of molten steel after RH vacuum breaking is avoided, and the method of adding the calcium-aluminum-iron alloy block into the RH vacuum tank can not only treat Al2O3The inclusion-like substance is properly denatured, and the castability of molten steel and the quality of casting blanks can be improved.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (7)
1. A method of reducing clogging of a submerged entry nozzle by a calcium aluminum iron alloy treatment, comprising:
(1) controlling the oxygen content and the temperature of the converter endpoint;
(2) modifying slag during tapping;
(3) after the molten steel enters RH, rapidly vacuumizing for decarburization;
(4) adding aluminum to deoxidize, wherein the adding amount of the aluminum ensures that Als in the deoxidized steel is 0.010-0.018%;
(5) after the deoxidation is finished, pure circulation is carried out for 3 minutes;
(6) simultaneously adding calcium, aluminum and iron and other alloys, and adjusting the Alt content in the steel to be within the range of 0.035-0.040% when the process is finished; the addition amount of the calcium, aluminum and iron enables the Ca content of the tundish molten steel to be 5-10 ppm;
(7) then pure circulation is carried out for 6-9 minutes;
(8) breaking vacuum and finishing refining.
2. The method of claim 1, wherein the oxygen content in step (1) is controlled to be 500-700ppm and the temperature is 1670-1685 ℃.
3. The method for reducing clogging of a submerged entry nozzle by calcium-aluminum-iron alloy treatment as claimed in claim 1, wherein said slag upgrading is performed by adding shot and small lime particles while tapping in step (2).
4. The method for reducing clogging of a submerged entry nozzle by calcium-aluminum-iron alloy treatment as claimed in claim 1, wherein said decarburization time in step (3) is controlled to 14-16 min.
5. A method for reducing the clogging of a submerged entry nozzle by a calcium-aluminium-iron alloy treatment according to claim 1, wherein said aluminium is added in step (4) in such an amount that the Als in the deoxidized steel is preferably 0.015%.
6. The method for reducing clogging of a submerged entry nozzle with a calcium-aluminum-iron alloy treatment according to claim 1, wherein said calcium-aluminum-iron addition in step (6) is calculated based on a target Alt content and said calcium-aluminum-iron alloy content.
7. A method for reducing the clogging of a submerged entry nozzle by a calcium-aluminium-iron alloy treatment according to claim 1, wherein in step (6) said other alloy is one or more of micro-carbon ferromanganese, ferromanganese or ferrophosphorus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810805313.2A CN109022681B (en) | 2018-07-20 | 2018-07-20 | Method for reducing blockage of submerged nozzle through calcium-aluminum-iron alloy treatment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810805313.2A CN109022681B (en) | 2018-07-20 | 2018-07-20 | Method for reducing blockage of submerged nozzle through calcium-aluminum-iron alloy treatment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109022681A CN109022681A (en) | 2018-12-18 |
| CN109022681B true CN109022681B (en) | 2020-06-19 |
Family
ID=64644834
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810805313.2A Active CN109022681B (en) | 2018-07-20 | 2018-07-20 | Method for reducing blockage of submerged nozzle through calcium-aluminum-iron alloy treatment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109022681B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109576441B (en) * | 2018-12-21 | 2020-12-15 | 首钢京唐钢铁联合有限责任公司 | RH refining method for controlling wettability of inclusions in low-carbon aluminum killed steel |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07224317A (en) * | 1994-02-14 | 1995-08-22 | Nisshin Steel Co Ltd | Production of high cleanliness steel |
| CN101906510A (en) * | 2010-08-16 | 2010-12-08 | 上海盛宝钢铁冶金炉料有限公司 | Steelmaking aluminum calcium ferrum deoxidizer and preparation method thereof |
| CN102719593B (en) * | 2011-03-29 | 2014-04-02 | 鞍钢股份有限公司 | Method for smelting ultra-low carbon steel |
| CN107012282B (en) * | 2016-01-27 | 2018-11-06 | 鞍钢股份有限公司 | Method for improving purity of high-quality ultra-low carbon steel |
| CN106148821B (en) * | 2016-07-13 | 2018-04-10 | 唐山钢铁集团有限责任公司 | Phosphorate the production technology of high-strength IF steel |
-
2018
- 2018-07-20 CN CN201810805313.2A patent/CN109022681B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109022681A (en) | 2018-12-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111270126B (en) | Niobium-titanium-nitrogen and titanium-nitrogen composite microalloyed HRB400E steel bar and production method thereof | |
| CN103627841B (en) | Control method for nitrogen content of molten steel of wear-resistant steel | |
| CN101962702B (en) | Method for controlling non-metallic inclusions in steel | |
| CN103741006B (en) | A kind of preparation method containing the low nitrogen stainless steel of Ti | |
| CN112899440A (en) | RH nitrogen-blowing alloying process for accurately controlling nitrogen content of nitrogen-containing steel | |
| CN108531807A (en) | A kind of heavy wall heavy caliber X80M pipelines clean steel and smelting process | |
| CN111041352B (en) | External refining production method of wire rod for cutting diamond wire | |
| CN104212934A (en) | Control method for titanium nitride inclusion of gear steel bar material | |
| CN111621621B (en) | Control method of Mn in molten steel in RH vacuum treatment process | |
| CN111254359A (en) | Corrosion-resistant rare earth bearing steel and preparation method thereof | |
| CN109022681B (en) | Method for reducing blockage of submerged nozzle through calcium-aluminum-iron alloy treatment | |
| CN107365884A (en) | Method for narrow-range control of carbon content of ultra-low carbon steel | |
| CN113913580A (en) | Production method of ultralow-carbon low-aluminum structural molten steel | |
| CN110317919B (en) | Low-cost production method of low-carbon enamel steel | |
| CN102443682A (en) | Method for controlling slagging of vacuum chamber | |
| TW201331377A (en) | Melting method of high cleanness steel | |
| CN102732678A (en) | Control method of oxygen in low-carbon low-silicon aluminum-killed steel | |
| CN109880970A (en) | A kind of technique promoting IF steel casting sequence | |
| CN113234894B (en) | Method for improving corrosion resistance of nitrogen-containing duplex stainless steel | |
| CN114908213A (en) | Method for treating Al in steel by using rare earth cerium element 2 O 3 Method for modifying inclusions | |
| RU2564373C1 (en) | Method of pipe steel production | |
| CN109023021B (en) | Steel plate with toughness improved by regulating Al element and manufacturing method thereof | |
| CN102816897A (en) | Method for reducing inclusions in low-silicon interstitial-free steel | |
| CN102816898A (en) | Method for modifying interstitial-free steel top slag | |
| JP5849667B2 (en) | Melting method of low calcium 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 |