CN114054739A - Submerged nozzle for promoting high efficiency and high cleanness and continuous casting production method - Google Patents
Submerged nozzle for promoting high efficiency and high cleanness and continuous casting production method Download PDFInfo
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- CN114054739A CN114054739A CN202111348157.XA CN202111348157A CN114054739A CN 114054739 A CN114054739 A CN 114054739A CN 202111348157 A CN202111348157 A CN 202111348157A CN 114054739 A CN114054739 A CN 114054739A
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- 238000009749 continuous casting Methods 0.000 title claims abstract description 29
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 27
- 230000001737 promoting effect Effects 0.000 title claims description 6
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 91
- 239000010959 steel Substances 0.000 claims abstract description 91
- 238000000034 method Methods 0.000 claims abstract description 25
- 230000008569 process Effects 0.000 claims abstract description 16
- 238000009434 installation Methods 0.000 claims abstract description 7
- 239000007789 gas Substances 0.000 claims description 40
- 238000005266 casting Methods 0.000 claims description 24
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 18
- 230000002093 peripheral effect Effects 0.000 claims description 12
- 229910052786 argon Inorganic materials 0.000 claims description 9
- 230000015572 biosynthetic process Effects 0.000 claims description 8
- 230000003749 cleanliness Effects 0.000 claims description 5
- 238000007654 immersion Methods 0.000 abstract description 7
- 230000024121 nodulation Effects 0.000 abstract description 5
- 230000009466 transformation Effects 0.000 abstract description 3
- 229910052755 nonmetal Inorganic materials 0.000 description 22
- 239000007788 liquid Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 4
- 238000007667 floating Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000009851 ferrous metallurgy Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- ZFXVRMSLJDYJCH-UHFFFAOYSA-N calcium magnesium Chemical compound [Mg].[Ca] ZFXVRMSLJDYJCH-UHFFFAOYSA-N 0.000 description 1
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- 230000001681 protective effect Effects 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/50—Pouring-nozzles
- B22D41/58—Pouring-nozzles with gas injecting means
-
- 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
- B22D11/16—Controlling or regulating processes or operations
- B22D11/18—Controlling or regulating processes or operations for pouring
-
- 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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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The present disclosure provides a promote high-efficient high clean immersion nozzle, contain: a wall part having an annular cross section to define a longitudinally extending molten steel flow passage, and both ends of the wall part in a longitudinal direction being provided with a molten steel inflow port and a molten steel outflow port communicating to the molten steel flow passage, respectively; and a microbubble generation unit installed to the wall portion at an installation position between the molten steel inflow port and the molten steel outflow port, and configured to supply microbubbles to the molten steel flow passage. The submerged nozzle is additionally provided with the micro-bubble generating unit at a reasonable position, micro-bubbles formed at a specific stage can fully capture nonmetallic inclusions, the problem of nodulation and current transformation of the submerged nozzle in the continuous casting process is solved, and meanwhile, the purity of molten steel is effectively improved. The present disclosure also provides a continuous casting production method using the submerged nozzle.
Description
Technical Field
The disclosure belongs to the technical field of ferrous metallurgy, and particularly relates to an immersion nozzle for promoting high efficiency and high cleanness and a continuous casting production method using the immersion nozzle.
Background
The steel is the most common important material in the fields of national defense, traffic, daily life and the like. With the progress of society and the development of science and technology, people have higher and higher requirements on the quality and performance of steel materials. Key quality indexes such as homogeneity, cleanliness and compactness of the steel material have important influence on the mechanical property of the product. For example, in the aspect of steel cleanliness, heterogeneous phases such as non-metallic inclusions can block the continuity of a matrix and influence the mechanical properties of steel products; part of the non-metallic inclusions can become crack nucleation points; and partial non-metal inclusions deteriorate the performance of the steel through different influence mechanisms, and reduce the fatigue life of the material. In the prior art, the form of the non-metallic inclusion is controlled by calcium treatment, calcium-magnesium composite treatment, rare earth treatment and the like, and the non-metallic inclusion removal is promoted by combining refining slag research, protective casting and tundish and crystallizer flow field research. However, the existing treatment methods involve a plurality of complicated processes, and the increase in raw materials and operation steps also increases the production cost accordingly.
With the development of continuous casting technology, continuous casting production equipment is also continuously improved. Among them, the submerged nozzle is widely used because it has advantages of preventing secondary oxidation and splashing of molten steel, adjusting the flow state and injection speed of molten steel, preventing non-metallic inclusions of mold flux from being involved in steel cement, and helping to promote floating of inclusions. However, the existing continuous casting equipment still has many problems in the production process, for example, the submerged nozzle nodulation causes the crystallizer liquid level fluctuation, the variable flow and the like, and the continuous casting production efficiency is seriously influenced.
Therefore, how to improve the production efficiency of continuous casting equipment and effectively remove non-metallic inclusions in continuous casting billets becomes an urgent problem to be solved in the technical field of ferrous metallurgy.
BRIEF SUMMARY OF THE PRESENT DISCLOSURE
In order to solve the prior art problem, the present disclosure provides a submerged nozzle for promoting high efficiency and high cleanliness, the submerged nozzle is additionally provided with a micro bubble generating unit at a reasonable position, micro bubbles formed at a specific stage can fully capture non-metallic inclusions, the problem of nodulation and current transformation of the submerged nozzle in the continuous casting process is improved, and meanwhile, the purity of molten steel is effectively improved. The present disclosure also provides a continuous casting production method using the submerged nozzle.
According to the present disclosure, there is provided an immersion nozzle for promoting high efficiency and high cleanliness, comprising:
a wall part having an annular cross section to define a longitudinally extending molten steel flow passage, and both ends of the wall part in a longitudinal direction being provided with a molten steel inflow port and a molten steel outflow port communicating to the molten steel flow passage, respectively; and
and a microbubble generation unit mounted to the wall portion at a mounting position between the molten steel inflow port and the molten steel outflow port, and configured to supply microbubbles to the molten steel flow path.
According to an embodiment of the present disclosure, the installation position is 250 to 320mm from the molten steel inflow port in the longitudinal direction of the wall portion.
According to an embodiment of the present disclosure, the microbubble generation unit includes:
a main gas flow passage communicating with an external gas source and embedded in the wall at the mounting position; and
the microbubble forms the passageway, and the microbubble forms the passageway and communicates main gas flow channel and molten steel flow channel.
According to an embodiment of the present disclosure, the microbubble generation unit further includes a base having a cross section matching the wall portion at the mounting position, and the main air flow passage is embedded in the base.
According to one embodiment of the present disclosure, the main gas flow passage is annular and disposed coaxially with the molten steel flow passage, and the plurality of microbubble formation passages are circumferentially disposed at equal intervals between the main gas flow passage and the molten steel flow passage.
According to one embodiment of the present disclosure, the microbubble formation channel and the main gas flow channel are inclined in a direction away from the molten steel inflow port at an included angle of 15 ° to 17 °.
According to one embodiment of the present disclosure, the diameter of the microbubble formation channel is 1/2 the diameter of the main gas flow channel.
According to one embodiment of the disclosure, the thickness of the wall at the mounting location is d, and the diameter of the main gas flow channel is d/4, wherein the outer peripheral edge of the main gas flow channel is d/4 away from the outer peripheral edge of the wall, and the inner peripheral edge of the main gas flow channel is d/2 away from the inner peripheral edge of the wall; the number of microbubble formation channels is 18.
According to the present disclosure, there is provided a continuous casting production method using the above-described submerged entry nozzle for casting.
According to one embodiment of the present disclosure, in a continuous casting process:
introducing high-temperature argon into the main gas flow channel, wherein the flow rate of the argon is controlled to be 0.20-0.50 NL/min;
controlling the casting superheat degree at 20-40 ℃; and
the pulling speed is controlled to be 0.45-1.70 m/min.
Due to the adoption of the technical scheme, compared with the prior art, the method has the following advantages:
1. according to the method, the micro-bubble generating unit is additionally arranged at a reasonable position of the submerged nozzle to form a micro-bubble film at a specific stage, so that the problem of nodulation and current transformation of the submerged nozzle in the continuous casting process is solved, the stability of a molten steel flow at an outlet of the submerged nozzle in a crystallizer is improved, and the production efficiency is effectively improved;
2. the submerged nozzle has the advantages of simple structure, easy modification and long service life, and effectively prolongs the service life of the crystallizer;
3. according to the continuous casting production method disclosed by the invention, the formed bubble clusters enter a molten pool in the crystallizer along with the molten steel flow, and are fully gathered and captured under the action of the flow field, so that the floating removal of inclusions is promoted, and the purity of the molten steel is improved;
4. the continuous casting production method does not involve the increase of raw materials and operation steps, and effectively reduces the production cost.
Drawings
FIG. 1 is a longitudinal cross-sectional view of a portion of a submerged entry nozzle according to the present disclosure;
fig. 2 is a longitudinal sectional view of a microbubble generation unit according to the present disclosure;
fig. 3 is a transverse sectional view of a microbubble generation unit according to the present disclosure.
In the drawings
100 wall parts, 110 molten steel inflow ports, 200 molten steel flow passages, 300 microbubble generating units, 310 main gas flow passages, 320 microbubble forming passages, 330 basal bodies.
Detailed Description
In order to make the objects, technical solutions and advantages of the present disclosure more apparent, the present disclosure is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the disclosure and are not intended to limit the disclosure.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein in the description is for the purpose of describing particular embodiments only and is not intended to limit the disclosure, e.g., the terms "length," "width," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," "outer," "lateral," "longitudinal," "vertical," etc., indicate an orientation or position based on that shown in the drawings, are for convenience of description only and are not to be construed as limiting the present disclosure. Wherein the term "transverse" is intended to mean a direction lying in the same plane as and perpendicular to "longitudinal" and "vertical" is intended to mean a direction perpendicular to the plane of "transverse" and "longitudinal".
The submerged nozzle is a pipeline for pouring molten steel, is a channel for the molten steel to enter the crystallizer from a tundish, protects the steel flow, prevents secondary oxidation of the molten steel, promotes impurities to float upwards, changes the flowing state of the molten steel in the crystallizer, improves the casting blank quality, prevents slag entrapment and the like, and plays an important role in improving the quality of steel and the continuous casting production capacity. Fig. 1 shows a longitudinal sectional view of a portion of a submerged entry nozzle according to the present disclosure, generally comprising a wall portion 100 and a micro-bubble generating unit 300 mounted to the wall portion 100. Wherein the wall part 100 has a circular cross-section to define a longitudinally extending molten steel flow passage 200, and a molten steel inflow port 110 and a molten steel outflow port (not shown) communicating to the molten steel flow passage 200 are provided at both ends of the wall part 100 in a longitudinal direction, respectively; the micro-bubble generating unit 300 is installed to the wall part 100 at an installation position between the molten steel inflow port 110 and the molten steel outflow port, and is provided to supply micro-bubbles to the molten steel flow path 200. In the casting process, the molten steel from the tundish enters the molten steel flow channel 200 from the molten steel inflow port 110, passes through the channel part formed by the microbubble generating unit 300, and then the microbubbles generated by the microbubble generating unit 300 are uniformly introduced into the molten steel. The microbubble generating unit 300 is preferably installed at a distance H of 250 to 320mm from the molten steel inflow port 110 along the longitudinal direction of the wall part 100, so as to control the distribution of the microbubble film along the specific cross section of the nozzle, thereby facilitating the incorporation of bubbles into the molten steel in an optimal state.
Fig. 2 and 3 show a longitudinal sectional view and a transverse sectional view, respectively, of one embodiment of a microbubble generation unit 300 according to the present disclosure. In this embodiment, the microbubble generation unit 300 includes a main gas flow path 310 that is in fluid communication with an external gas source and is embedded in the wall portion 100 at the installation position, and a microbubble generation path 320 that communicates the main gas flow path 310 with the molten steel flow path 200. The main gas flow path 310 and the microbubble generating path 320 may be directly installed in the wall portion 100 in an inlay manner. Alternatively, the main gas flow path 310 and the microbubble generation path 320 may also be mounted to the wall portion 100 by embedding a base 330 having a similar structure to the wall portion 100, and then by means of the base 330. Wherein the base 330 may have a cross-section matching the wall portion 100 at the installation position and constitute a portion of the molten steel flow channel 200.
The main gas flow passage 310 may be annular and disposed coaxially with the molten steel flow passage 200, and a plurality of microbubble generating passages 320 are circumferentially disposed at equal intervals between the main gas flow passage 310 and the molten steel flow passage 200. Preferably, the diameter of the microbubble formation passage 320 may be smaller than the diameter of the main gas flow passage 310; the micro-bubble forming passage 320 and the main gas flow passage 310 may be inclined in a direction away from the molten steel inflow port 110 at an included angle a of 15 ° to 17 °, that is, the inclined direction is lower near the molten steel flow side and higher away from the molten steel flow side, so as to increase the distance of the gas flowing through the micro-bubble forming passage 320, which is beneficial to the formation of micro-bubbles. In the embodiment of the present disclosure, if the thickness of the wall portion 100 at the installation position is d, the diameter of the main air flow passage 310 may be designed to be d/4, and the diameter of the microbubble generating passage 320 may be designed to be d/8. Wherein the outer peripheral edge of the main gas flow passage 310 is spaced apart from the outer peripheral edge of the wall portion 100 by d/4, the inner peripheral edge of the main gas flow passage 310 is spaced apart from the inner peripheral edge of the wall portion 100 by d/2, and 18 microbubble formation passages 320 are uniformly circumferentially arranged between the main gas flow passage 310 and the molten steel flow passage 200. The person skilled in the art can also make appropriate adjustments to the above parameters depending on the actual operating conditions.
In the continuous casting production method for pouring by using the submerged nozzle, in the continuous casting process, along with the injection of molten steel, an external gas source is controlled to introduce high-temperature argon into the main gas flow channel 310 at the speed of 0.20-0.50 NL/min. Meanwhile, the casting superheat degree is preferably controlled to be 20-40 ℃; the pulling speed is preferably controlled to be 0.45-1.70 m/min.
According to this open high-efficient high clean immersion nozzle of promotion is through addding the microbubble generating element in mouth of a river reasonable position, form the micro bubble membrane at specific stage, the micro bubble membrane is along the specific cross-section circumference evenly distributed in mouth of a river, form gaseous state dielectric layer between wall portion 100 inboard and molten steel stream, this dielectric layer can reduce the area of contact of molten steel stream and mouth of a river wall portion 100 inboard by a great extent, it grows up to reduce the inboard bonding aggregation of molten steel nonmetal inclusion in wall portion 100, improve continuous casting process immersion nozzle nodulation deflector problem, improve the stability of molten steel stream outlet department molten steel stream of the inside immersion nozzle of crystallizer. In addition, the bubble clusters generated by the micro-bubble generating unit enter a molten pool in the crystallizer along with the molten steel flow, and are fully gathered and captured under the action of the flow field, so that the floating removal of inclusions is promoted, and the purity of the molten steel is improved.
The following are specific examples of the continuous casting production method according to the present disclosure.
Example 1
In this example, a 200mm x 200mm section 82b high carbon hard wire billet was produced using a method according to the present disclosure. The following parameters were used in the production process:
| distance H between the mounting position and the molten steel inlet | 250mm |
| Thickness of the wall | d |
| Diameter of the main gas flow channel | d/4 |
| Diameter of micro-bubble forming channel | d/8 |
| Argon flow | 0.30NL/min |
| Inner diameter of outlet of submerged nozzle | Φ20mm |
| Degree of superheat of casting | 20℃ |
| Pulling speed | 1.20m/min |
After the implementation of the process, the square billet is sampled and detected, and compared with the square billet produced by using the existing submerged nozzle without a micro-bubble generating unit, the result shows that: the number of the single-tundish casting furnaces is increased from 9-11 furnaces to more than 14 furnaces; the liquid level stability of the crystallizer is obviously improved in the casting process; and detecting the grade of the non-metal inclusions of the rolled product, wherein the ratio of the class B and class C non-metal inclusions which are less than or equal to 1.0 is increased from 52.2% to 78.6%, and the ratio of the class D non-metal inclusions which are less than or equal to 0.5 is increased from 63.7% to 92.1%.
Example 2
In this example, a 200mm x 200mm section 82b high carbon hard wire billet was produced using a method according to the present disclosure. The following parameters were used in the production process:
| distance H between the mounting position and the molten steel inlet | 250mm |
| Thickness of the wall | d |
| Diameter of the main gas flow channel | d/4 |
| Diameter of micro-bubble forming channel | d/8 |
| Argon flow | 0.35NL/min |
| Inner diameter of outlet of submerged nozzle | Φ20mm |
| Degree of superheat of casting | 35℃ |
| Pulling speed | 1.70m/min |
After the implementation of the process, the square billet is sampled and detected, and compared with the square billet produced by using the existing submerged nozzle without a micro-bubble generating unit, the result shows that: the number of the single-tundish casting furnaces is increased from 9-11 furnaces to more than 14 furnaces; the liquid level stability of the crystallizer is obviously improved in the casting process; and detecting the grade of the non-metal inclusions of the rolled product, wherein the ratio of the class B and class C non-metal inclusions which are less than or equal to 1.0 is increased from 52.2% to 78.6%, and the ratio of the class D non-metal inclusions which are less than or equal to 0.5 is increased from 63.7% to 92.1%.
Example 3
In this example, a 360mm x 450mm section 34CrMo4 oxygen cylinder steel bloom was produced using a method according to the present disclosure. The following parameters were used in the production process:
after the implementation of the process, the square billet is sampled and detected, and compared with the square billet produced by using the existing submerged nozzle without a micro-bubble generating unit, the result shows that: the number of the single-tundish casting furnaces is increased from 8-12 furnaces to more than 14 furnaces; the liquid level stability of the crystallizer is obviously improved in the casting process; and detecting the grade of the non-metal inclusions of the rolled product, wherein the ratio of the class B and class C non-metal inclusions which are less than or equal to 1.0 is increased from 57.1% to 87.2%, and the ratio of the class D non-metal inclusions which are less than or equal to 0.5 is increased from 75.6% to 91.0%.
Example 4
In this example, a 360mm x 450mm section 34CrMo4 oxygen cylinder steel bloom was produced using a method according to the present disclosure. The following parameters were used in the production process:
| distance H between the mounting position and the molten steel inlet | 320mm |
| Thickness of the wall | d |
| Diameter of the main gas flow channel | d/4 |
| Diameter of micro-bubble forming channel | d/8 |
| Argon flow | 0.50NL/min |
| Inner diameter of outlet of submerged nozzle | Φ45mm |
| Degree of superheat of casting | 40℃ |
| Pulling speed | 0.52m/min |
After the implementation of the process, the square billet is sampled and detected, and compared with the square billet produced by using the existing submerged nozzle without a micro-bubble generating unit, the result shows that: the number of the single-tundish casting furnaces is increased from 8-12 furnaces to more than 14 furnaces; the liquid level stability of the crystallizer is obviously improved in the casting process; and detecting the grade of the non-metal inclusions of the rolled product, wherein the ratio of the class B and class C non-metal inclusions which are less than or equal to 1.0 is increased from 57.1% to 87.2%, and the ratio of the class D non-metal inclusions which are less than or equal to 0.5 is increased from 75.6% to 91.0%.
Example 5
In this example, a 200mm x 200mm section HRB400 steel billet for construction was produced using the method according to the present disclosure. The following parameters were used in the production process:
| distance H between the mounting position and the molten steel inlet | 270mm |
| Thickness of the wall | d |
| Diameter of the main gas flow channel | d/4 |
| Diameter of micro-bubble forming channel | d/8 |
| Argon flow | 0.20NL/min |
| Inner diameter of outlet of submerged nozzle | Φ20mm |
| Degree of superheat of casting | 20℃ |
| Pulling speed | 1.20m/min |
After the implementation of the process, the square billet is sampled and detected, and compared with the square billet produced by using the existing submerged nozzle without a micro-bubble generating unit, the result shows that: the number of the single-tundish casting furnaces is increased from 12-13 furnaces to more than 17 furnaces; the liquid level stability of the crystallizer is obviously improved in the casting process; and detecting the grade of the non-metal inclusions of the rolled product, wherein the ratio of the class B non-metal inclusions to the class C non-metal inclusions which are less than or equal to 1.0 is increased from 45.5% to 71.2%, and the ratio of the class D non-metal inclusions which are less than or equal to 0.5 is increased from 68.2% to 81.9%.
Example 6
In this example, a 200mm x 200mm section HRB400 steel billet for construction was produced using the method according to the present disclosure. The following parameters were used in the production process:
after the implementation of the process, the square billet is sampled and detected, and compared with the square billet produced by using the existing submerged nozzle without a micro-bubble generating unit, the result shows that: the number of the single-tundish casting furnaces is increased from 12-13 furnaces to more than 17 furnaces; the liquid level stability of the crystallizer is obviously improved in the casting process; and detecting the grade of the non-metal inclusions of the rolled product, wherein the ratio of the class B non-metal inclusions to the class C non-metal inclusions which are less than or equal to 1.0 is increased from 45.5% to 71.2%, and the ratio of the class D non-metal inclusions which are less than or equal to 0.5 is increased from 68.2% to 81.9%.
The above embodiment illustrates that, by adopting the technical scheme of the present disclosure, the probability of clogging of the submerged nozzle in the continuous casting process and flow-changing water shutoff is significantly reduced, and simultaneously, capturing, collision gathering and removal of non-metallic inclusions in molten steel inside the crystallizer can be more fully promoted, so that efficient and high-cleanliness production control in the continuous casting process of large and small-section square billets and rectangular billets is realized, and important basic technical conditions are established for efficiently and stably producing high-quality continuous casting billets.
The above examples merely represent embodiments of the present disclosure, which are described in more detail and detail, but are not to be construed as limiting the scope of the present disclosure. It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the concept of the present disclosure, and these changes and modifications are all within the scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the appended claims.
Claims (10)
1. A submerged entry nozzle for promoting high efficiency and high cleanliness, comprising:
a wall portion having an annular cross section to define a longitudinally extending molten steel flow passage, and both ends of the wall portion in a longitudinal direction being provided with a molten steel inflow port and a molten steel outflow port communicating to the molten steel flow passage, respectively; and
a microbubble generation unit installed to the wall portion at an installation position between the molten steel flow inlet and the molten steel flow outlet, and configured to supply microbubbles to the molten steel flow passage.
2. The submerged entry nozzle of claim 1, wherein the mounting position is 250-320 mm from the molten steel inflow port in the longitudinal direction of the wall portion.
3. Submerged entry nozzle according to claim 1, characterised in that said microbubble generation unit comprises:
a main gas flow passage communicating with an external gas source and embedded in the wall at the mounting location; and
and the micro-bubble forming channel is communicated with the main gas flow channel and the molten steel flow channel.
4. Submerged entry nozzle according to claim 3, characterised in that the microbubble generation unit further comprises a base body having a cross section matching the wall at the mounting location, the main gas flow channel being embedded in the base body.
5. The submerged entry nozzle of claim 3 or 4, characterized in that the main gas flow passage is annular and is arranged coaxially with the molten steel flow passage, and the plurality of microbubble generation passages are circumferentially arranged at equal intervals between the main gas flow passage and the molten steel flow passage.
6. The submerged entry nozzle of claim 5, characterized in that the microbubble generating passage is inclined away from the molten steel inflow opening at an angle of 15 ° to 17 ° with respect to the plane of the main gas flow passage.
7. Submerged entry nozzle according to claim 6, characterised in that the diameter of the microbubble generation channel is 1/2 times the diameter of the main gas flow channel.
8. Submerged entry nozzle according to claim 7,
the thickness of the wall at the mounting position is d, and the diameter of the main air flow channel is d/4, wherein the outer peripheral edge of the main air flow channel is d/4 away from the outer peripheral edge of the wall, and the inner peripheral edge of the main air flow channel is d/2 away from the inner peripheral edge of the wall;
the number of the microbubble formation channels is 18.
9. A continuous casting production method characterized by casting using the submerged entry nozzle of any one of claims 1 to 8.
10. The continuous casting production method according to claim 9, characterized in that, in the continuous casting process:
introducing high-temperature argon into the main gas flow channel, wherein the flow rate of the argon is controlled to be 0.20-0.50 NL/min;
controlling the casting superheat degree at 20-40 ℃; and
the pulling speed is controlled to be 0.45-1.70 m/min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111348157.XA CN114054739A (en) | 2021-11-15 | 2021-11-15 | Submerged nozzle for promoting high efficiency and high cleanness and continuous casting production method |
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| CN206305443U (en) * | 2016-12-08 | 2017-07-07 | 新疆八一钢铁股份有限公司 | Ladle nozzle argon gas blowing device |
| CN208322099U (en) * | 2018-06-04 | 2019-01-04 | 河钢股份有限公司 | A kind of curved surface sealing two-way argon blowing long nozzle structure |
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Application publication date: 20220218 |