Backflushable anti-flocculation flow port and method of use

Abstract

The present application belongs to the technical field of metallurgical continuous casting, and particularly relates to a back-flushable anti-flocculation flow nozzle and a use method. The nozzle comprises a nozzle body, a molten steel inlet, a molten steel outlet, a main air inlet pipe and a secondary air inlet pipe. The molten steel inlet is arranged at the top of the nozzle body, and the molten steel outlet is arranged at the bottom of the nozzle body. The main air inlet pipe and the secondary air inlet pipe are radially and symmetrically arranged in the middle of the nozzle body. The main air inlet pipe and the secondary air inlet pipe have different diameters. The nozzle has the following advantages: the symmetrically arranged main air inlet pipe and secondary air inlet pipe with different diameters form an asymmetric air flow, and forced turbulence is generated to enhance the inner wall scouring force, break the steady state environment of flocculation deposition, accelerate the peeling of the attached impurities, and remove the flocculation. The nozzle can make up for the technical deficiency of the existing continuous casting process, reduce the loss caused by flocculation, significantly reduce the use cost of continuous casting materials, and has important engineering application value for improving the continuous casting.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical continuous casting technology, and particularly relates to a backwashable anti-flocculation water outlet and its usage method. Background Technology

[0002] The upper cup of the tundish top nozzle matches the stopper rod head. Flow control is achieved by adjusting the opening between the cup and the stopper rod head. The lower part connects to the submerged entry nozzle, guiding the molten steel from the tundish top nozzle cavity to the submerged entry nozzle. During the production of medium carbon steel, nozzle turbulence frequently occurs: turbulent material accumulates at the cup-shaped opening of the tundish top nozzle, not only reducing the inner diameter of the cup-shaped opening and affecting the normal steel throughput, but also causing the cup-shaped opening to become uneven due to the adhesion of high-temperature turbulent material. This prevents proper matching with the stopper rod head, resulting in increased stopper rod stroke and insufficient steel throughput to meet normal casting requirements, affecting the continuity of the entire casting process; furthermore, the process flow is irregular. Turbulence not only causes slab quality defects and increases production costs, but can also lead to production accidents. Therefore, controlling turbulence, reducing production accidents, and improving slab quality are important issues that we are continuously working on to address.

[0003] In the prior art, patent publication number CN107127332A discloses a method for manufacturing an immersion nozzle to prevent turbulence. Based on the high-temperature resistance of Y2O3 and its ability to reduce the thermal expansion rate and high-temperature thermal shock resistance of ZrO2-based materials when combined with MgO, a ZrO2-based composite material is used as the inner inlay layer of the immersion nozzle. This method is suitable for casting aluminum-killed steel grades, improving steel cleanliness and effectively preventing turbulence at the nozzle. Patent publication number CN210045989U discloses an argon-blown immersion nozzle with argon-blowing holes located on the inner wall of the upper or lower third of the nozzle body. Simultaneously, the nozzle outlet uses two or four steel outlet holes symmetrically arranged on the side of the nozzle body, effectively preventing turbulence in molten steel. However, this solution only delays adhesion and cannot eliminate turbulence; furthermore, the high-cost material is uneconomical for ordinary steel grades. The aforementioned technical solutions, which prevent clogging and optimize molten steel quality through uniform argon blowing or multi-channel air blowing, have low anti-flooding efficiency and high cost of consumables in continuous casting. Therefore, there is an urgent need for a new type of anti-flooding nozzle with backwashing capability and its application process to address the shortcomings of existing anti-flooding technologies in continuous casting. This would have significant engineering application value for improving continuous casting, and would be crucial for saving resources and energy, reducing losses caused by flooding, lowering production costs, and enhancing the international competitiveness of steel. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a backwashable anti-flocculation inlet and its usage method. The backwashing method breaks the steady-state environment of flocculation deposition, while accelerating the removal of attached impurities, improving anti-flocculation efficiency, reducing losses caused by flocculation, and lowering production and application costs.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A backwashable anti-flocculation water inlet includes an inlet body, a molten steel inlet, a molten steel outlet, a main air inlet pipe, and a secondary air inlet pipe. The inlet body has a molten steel inlet at the top and a molten steel outlet at the bottom. The main air inlet pipe and the secondary air inlet pipe are radially symmetrically arranged in the middle of the inlet body, and the main air inlet pipe and the secondary air inlet pipe have different orifice diameters.

[0007] A vent valve is connected to the upper part of the water inlet body.

[0008] The ratio of the orifice diameter of the vent valve to that of the main intake pipe is 1:(2.5~3.5), and the thickness of the vent valve outlet is 3~5cm.

[0009] The aperture ratio of the main intake pipe to the auxiliary intake pipe is 1:(1.35~1.45) or 1:(0.75~0.85); the wall thickness of the main intake pipe and the auxiliary intake pipe is 2~5cm.

[0010] The main air intake pipe, auxiliary air intake pipe, and vent valve are made of the same material as the water inlet body.

[0011] A method for using a backwashable anti-flocculation nozzle: During normal use, the main air inlet and auxiliary air inlet are closed. Whenever the number of consecutive casting ladles is ≥4 or the fluctuation range of the molten steel level in the crystallizer is continuously greater than ±3mm, the nozzle is backwashed rapidly using a pulse-type method:

[0012] a. While keeping the molten steel inlet and outlet unobstructed, connect the main air inlet pipe and the auxiliary air inlet pipe to different high-temperature resistant air inlet pipes respectively;

[0013] b. Adjust the opening of the main intake pipe and the auxiliary intake pipe to 5%~10%;

[0014] c. Open the high-pressure inert gas valve connected to the intake pipe to maintain a high-pressure state in the channel;

[0015] d. Adjust the opening of the main intake manifold and the auxiliary intake manifold to 80%~90%;

[0016] e. Within 2-4 seconds, quickly adjust the air pressure in the intake pipe to 10-15 MPa and rapidly restore it to a high-pressure state to perform pulse-type backwashing on the water inlet; after rinsing, rapidly restore the high-pressure state and adjust the opening of the main intake pipe and auxiliary intake pipe to 5%-10% again;

[0017] f. If the steel produced is a type with severe turbulence, repeat steps a to e 2 to 3 times.

[0018] The intake pipe is filled with inert gas, and the high pressure is 5~8MPa inert gas pressure. The inert gas is either Ar or He.

[0019] In step e, the pulse backwashing is performed 10 to 15 times within a 30 to 60-second backwashing cycle.

[0020] In step e, during the pulse backwashing process, if the fluctuation range of the liquid level in the tundish is greater than ±3mm, the venting valve is opened to release the pressure; or inert gas is introduced through the venting valve to enhance the stirring of the molten steel in the nozzle; if the turbulence is severe during the pulse backwashing process, the calcium wire is fed into the turbulence position through the venting valve.

[0021] In step f, if the turbulence state is not significantly improved within a 2-4s backwashing cycle, the pressure ratio between the main air inlet pipe and the auxiliary air inlet pipe is adjusted to 1:(2.5-3.5) or 1:(0.25-0.5) within the pressure limit range.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. This invention overcomes the shortcomings of existing anti-flocculation technology in continuous casting processes, reduces losses caused by flocculation, significantly lowers the cost of continuous casting consumables, and has important engineering application value for improving continuous casting.

[0024] 2. The present invention uses symmetrically arranged main and auxiliary air intake pipes of different diameters to form an asymmetrical airflow, which forces the generation of turbulence, enhances the scouring force on the inner wall, breaks the steady-state environment of turbulent material deposition, and accelerates the stripping of attached impurities and removes turbulent material.

[0025] 3. The conventional use of the sprue of this invention is the same as that of ordinary sprues. Whenever the number of consecutive pouring tanks is ≥4 or when turbulence is observed by instruments, inert gas is introduced through the main and auxiliary air inlet pipes for rapid, asymmetrical high-pressure backwashing to clear the sprue and remove turbulent material. Alternatively, high-pressure inert gas can be introduced through the lower vent valve to form a passage, or calcium wire can be directly fed in from the lower vent valve to directly solve the turbulence problem. This prevents impurities from accumulating and growing on the inner wall of the sprue, and the regular rapid flushing of the sprue fundamentally eliminates the accumulation of impurities on the inner wall of the sprue.

[0026] 4. Compared with conventional sprue, this invention can be directly applied in areas where turbulence blockage frequently occurs, which is of great significance for saving resources and energy, reducing losses caused by turbulence, lowering production and application costs, and improving the international competitiveness of steel. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention.

[0028] In the diagram: 1-Sprue body, 2-Steel liquid inlet, 3-Steel liquid outlet, 4-Main air inlet pipe, 5-Secondary air inlet pipe, 6-Relief valve. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0030] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0031] Example 1:

[0032] A backwashable anti-flocculation water outlet and its application process in the production of medium carbon steel are as follows:

[0033] See Figure 1 The backwashable anti-flocculation sprue consists of six parts: sprue body 1 (made of refractory material), molten steel inlet 2, molten steel outlet 3, main air inlet pipe 4, auxiliary air inlet pipe 5, and vent valve 6. The molten steel inlet 2 is located at the top of the sprue body 1, and the molten steel outlet 3 is located at the bottom. During casting, molten steel flows into the sprue body 1 from the molten steel inlet 2 and flows out from the molten steel outlet 3. In the middle of the sprue body 1, the main air inlet pipe 4 and the auxiliary air inlet pipe 5 are symmetrically arranged about the central axis of the sprue body 1; their diameters are different, with a diameter ratio of 1:0.85 and a wall thickness of 5cm. The main air inlet pipe 4 and the auxiliary air inlet pipe 5 are closed during normal production.

[0034] A vent valve 6 is installed on the upper part of the sprue body 1. When the air / liquid pressure inside the sprue body 1 is too high, it can smoothly release the gas / liquid; or it can precisely feed calcium wire into the sprue through the vent valve 6 to quickly solve the turbulence problem. The vent valve 6 is closed during normal production. The diameter ratio of the vent valve 6 to the main air inlet pipe 4 is 1:3.5, and the outlet thickness is 5cm. The main air inlet pipe 4, the auxiliary air inlet pipe 5, and the vent valve 6 are made of the same material as the sprue body 1.

[0035] The normal usage method for backwashable nozzles is the same as that for ordinary nozzles. However, whenever the number of consecutive casting batches is ≥4 or when turbulence is observed by instruments (the fluctuation range of the molten steel level in the crystallizer is continuously greater than ±3mm), the nozzle should be backwashed rapidly using a pulse-type method to prevent turbulence events from occurring:

[0036] a. While keeping the molten steel inlet 2 and molten steel outlet 3 unobstructed, connect the main air inlet pipe 4 and the auxiliary air inlet pipe 5 to two high-temperature resistant air inlet pipes (the air inlet pipes can withstand the temperature of the nozzle and will not melt); the inert gas is He.

[0037] b. Open the main air intake pipe 4 and the auxiliary air intake pipe 5 by 10%, but do not open them all the way to prevent molten steel from overflowing.

[0038] c. Open the high-pressure inert gas valve connected to the high-temperature resistant intake pipe to maintain a high pressure of 8MPa in the channel;

[0039] d. Open the main intake pipe 4 and the auxiliary intake pipe 5 to 90%;

[0040] e. Within 2-4 seconds, rapidly increase the air pressure in the high-temperature resistant air inlet pipes on both sides to 15MPa, and then quickly reduce it back to 8MPa high pressure to perform pulse-type backwashing on the nozzle. After backwashing, quickly restore the high pressure state and close the main air inlet pipe 4 and the auxiliary air inlet pipe 5 to 10% again. In a 45-second backwashing cycle, the number of backwashing cycles is 15. If the turbulence is severe, the calcium wire can be precisely introduced into the turbulence location through the lower relief valve 6 to quickly resolve the turbulence problem; high-pressure inert gas can also be introduced through the lower relief valve 6 to enhance the stirring of the molten steel in the nozzle and improve the backwashing effect; if large fluctuations in the liquid level of the tundish are detected, open the relief valve 6 to release excess pressure.

[0041] f. If the steel grade being produced is one with severe turbulence, repeat steps a-e 2-3 times. If the turbulence condition does not significantly improve within a 13-second backwash cycle, adjust the air pressure ratio between the main intake pipe 4 and the auxiliary intake pipe 5 to 1:0.5 within the pressure limit range. Increase the air pressure on one side to forcefully purge and clear the blockage.

[0042] Using the above method, the average service life of the sprue reaches more than 25 hours.

[0043] Example 2:

[0044] A backwashable anti-flocculation water outlet and its application process in the production of medium carbon steel are as follows:

[0045] The difference between the backwashable anti-flocculent water outlet structure and that of Example 1 is that the diameter ratio of the main air inlet pipe 4 to the auxiliary air inlet pipe 5 is 1:1.35, and the pipe wall thickness is 2cm. The diameter ratio of the vent valve 6 to the main air inlet pipe 4 is 1:2.5, and the outlet thickness of the vent valve 6 is 3cm.

[0046] The normal usage method for backwashable nozzles is the same as that for ordinary nozzles. However, whenever the number of consecutive casting batches is ≥4 or when turbulence is observed by instruments (the fluctuation range of the molten steel level in the crystallizer is continuously greater than ±3mm), the nozzle should be backwashed rapidly using a pulse-type method to prevent turbulence events from occurring:

[0047] a. While keeping the molten steel inlet 2 and molten steel outlet 3 unobstructed, connect the main air inlet pipe 4 and the auxiliary air inlet pipe 5 to different high-temperature resistant air inlet pipes respectively; the inert gas is He;

[0048] b. Open the main air intake pipe 4 and the auxiliary air intake pipe 5 to 5%, but do not open them directly to prevent molten steel from overflowing.

[0049] c. Open the high-pressure inert gas valve connected to the high-temperature resistant intake pipe to maintain a high pressure of 5MPa in the channel;

[0050] d. Open the main intake pipe 4 and the auxiliary intake pipe 5 to 80%;

[0051] e. Within 3 seconds, rapidly increase the air pressure in the high-temperature resistant air inlet pipes on both sides to 10MPa, and then quickly reduce it back to a high-pressure state of 5MPa to perform pulse-type backwashing on the nozzle. After backwashing, quickly restore the high-pressure state and close the main air inlet pipe 4 and the auxiliary air inlet pipe 5 to 5% again. In a 30-second backwashing cycle, the number of backwashing cycles is 10. If the turbulence is severe, the calcium wire can be precisely introduced into the turbulence location through the lower relief valve 6 to quickly resolve the turbulence problem; high-pressure inert gas can also be introduced through the lower relief valve 6 to enhance the stirring of the molten steel in the nozzle and improve the backwashing effect; if large fluctuations in the liquid level of the tundish are detected, the relief valve 6 is opened to release excess pressure.

[0052] f. If the steel grade being produced is one with severe turbulence, repeat steps a-e 2-3 times. If the turbulence condition does not significantly improve within a 2-second backwash cycle, adjust the air pressure ratio between the main air inlet pipe 4 and the auxiliary air inlet pipe 5 to 1:2.5 within the pressure limit range. Increase the air pressure on one side to forcefully purge and clear the blockage.

[0053] Using the above method, the average service life of the water inlet reaches more than 22.5 hours.

[0054] Example 3:

[0055] A backwashable anti-flocculation water outlet and its application process in the production of medium carbon steel are as follows:

[0056] The difference between the backwashable anti-flocculent water outlet structure and that of Example 1 is that the diameter ratio of the main air inlet pipe 4 to the auxiliary air inlet pipe 5 is 1:1.07, and the pipe wall thickness is 3cm. The diameter ratio of the vent valve 6 to the main air inlet pipe 4 is 1:3, and the outlet thickness of the vent valve 6 is 4cm.

[0057] The normal usage method for backwashable nozzles is the same as that for ordinary nozzles. However, whenever the number of consecutive casting batches is ≥4 or when turbulence is observed by instruments (the fluctuation range of the molten steel level in the crystallizer is continuously greater than ±3mm), the nozzle should be backwashed rapidly using a pulse-type method to prevent turbulence events from occurring:

[0058] a. While keeping the molten steel inlet 2 and molten steel outlet 3 unobstructed, connect the main air inlet pipe 4 and the auxiliary air inlet pipe 5 to different high-temperature resistant air inlet pipes respectively; the inert gas is He;

[0059] b. Open the main air intake pipe 4 and the auxiliary air intake pipe 5 by 8%; do not open them all the way to prevent molten steel from overflowing.

[0060] c. Open the high-pressure inert gas valve connected to the high-temperature resistant intake pipe to maintain a high pressure of 6MPa in the channel;

[0061] d. Open the main intake pipe 4 and the auxiliary intake pipe 5 to 85%;

[0062] e. Within 3-4 seconds, rapidly increase the air pressure in the high-temperature resistant air inlet pipes on both sides to 13MPa, and then quickly reduce it back to 7MPa high pressure to perform pulse-type backwashing on the nozzle. After backwashing, quickly restore the high pressure state, and close the main air inlet pipe 4 and the auxiliary air inlet pipe 5 to 7% again. In a 40-second backwashing cycle, the number of backwashing cycles is 12. If the turbulence is severe, the calcium wire can be precisely introduced into the turbulence location through the lower relief valve 6 to quickly resolve the turbulence problem; high-pressure inert gas can also be introduced through the lower relief valve 6 to enhance the stirring of the molten steel in the nozzle and improve the backwashing effect; if large fluctuations in the liquid level of the tundish are detected, open the relief valve 6 to release excess pressure.

[0063] f. If the steel grade being produced is one with severe turbulence, repeat steps a-e 2-3 times. If the turbulence condition does not significantly improve within a 3-second backwash cycle, adjust the air pressure ratio on both sides to 1:0.25 within the pressure limit range. Increase the air pressure on one side to forcefully purge and clear the turbulence.

[0064] Using the above method, the average service life of the water inlet reaches more than 27 hours.

[0065] Comparative Example 1:

[0066] Using a conventional sprue, a medium carbon steel was produced at a domestic steel plant. During the continuous casting of four ladles, turbulence occurred and the sprue became blocked, so the sprue was replaced.

[0067] Comparative analysis shows that applying a backwashable anti-flocculent sprue and its application method to address the shortcomings of existing anti-flocculent technology in continuous casting processes will significantly reduce the cost of consumables used in continuous casting and has significant engineering application value for improving continuous casting. Developing a backwashable anti-flocculent sprue and its application method is of great significance for saving resources and energy, reducing losses caused by flocculation, lowering production and application costs, and enhancing the international competitiveness of steel.

[0068] Those skilled in the art should recognize that the above embodiments are merely illustrative of the invention and not intended to limit it, but are similarly limited to the scope of the invention. Variations and modifications to the above embodiments will fall within the protection scope of the claims. It should be understood that the endpoints and values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of various ranges, the endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0069] It should be noted that, in this document, terms such as "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Furthermore, the term "and / or" as used herein is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone.

[0070] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for using a backwashable anti-flocculation water outlet, characterized in that, The backwashable anti-flocculation water inlet includes a water inlet body, a molten steel inlet, a molten steel outlet, a main air inlet pipe, and a secondary air inlet pipe. The top of the water inlet body is provided with a molten steel inlet, and the bottom is provided with a molten steel outlet. The main air inlet pipe and the secondary air inlet pipe are radially symmetrically arranged in the middle of the water inlet body, and the orifice diameters of the main air inlet pipe and the secondary air inlet pipe are different. A vent valve is connected to the upper part of the water inlet body. When using a backwashable anti-flocculation inlet, the main air inlet and auxiliary air inlet are closed. Whenever the number of consecutive casting ladles is ≥4 or the fluctuation of the molten steel level in the crystallizer is continuously greater than ±3mm, the inlet is backwashed rapidly using a pulse-type method: Step a. While keeping the molten steel inlet and outlet unobstructed, connect the main air inlet pipe and the auxiliary air inlet pipe to different high-temperature resistant air inlet pipes respectively; Step b. Adjust the opening of the main intake manifold and the auxiliary intake manifold to 5%~10%; Step c. Open the high-pressure inert gas valve connected to the intake pipe to maintain a high-pressure state in the channel; Step d. Adjust the opening of the main intake manifold and the auxiliary intake manifold to 80%~90%; Step e. Within 2-4 seconds, quickly adjust the air pressure in the intake pipe to 10-15 MPa and rapidly restore it to a high-pressure state to perform pulse-type backwashing on the water inlet; after rinsing, rapidly restore the high-pressure state and adjust the opening of the main intake pipe and auxiliary intake pipe to 5%-10% again; Step f. If the produced steel grade is one with severe turbulence, repeat steps a to e 2 to 3 times.

2. The method of using a backwashable anti-flocculation water outlet according to claim 1, characterized in that, The ratio of the orifice diameter of the vent valve to that of the main intake pipe is 1:(2.5~3.5), and the thickness of the vent valve outlet is 3~5cm.

3. The method of using a backwashable anti-flocculation water outlet according to claim 1, characterized in that, The aperture ratio of the main intake pipe to the auxiliary intake pipe is 1:(1.35~1.45) or 1:(0.75~0.85); the wall thickness of the main intake pipe and the auxiliary intake pipe is 2~5cm.

4. The method of using a backwashable anti-flocculation water outlet according to claim 1, characterized in that, The main air intake pipe, auxiliary air intake pipe, and vent valve are made of the same material as the water inlet body.

5. The method of using a backwashable anti-flocculation water outlet according to claim 1, characterized in that, The intake pipe is filled with inert gas, and the high pressure is 5~8MPa inert gas pressure. The inert gas is either Ar or He.

6. The method of using a backwashable anti-flocculation water outlet according to claim 1, characterized in that, In step e, the pulse backwashing is performed 10 to 15 times within a 30 to 60-second backwashing cycle.

7. The method of using a backwashable anti-flocculation water outlet according to claim 1, characterized in that, In step e, during the pulse backwashing process, if the fluctuation range of the liquid level in the tundish is greater than ±3mm, the venting valve is opened to release the pressure; or inert gas is introduced through the venting valve to enhance the stirring of the molten steel in the nozzle; if the turbulence is severe during the pulse backwashing process, the calcium wire is fed into the turbulence position through the venting valve.

8. The method of using a backwashable anti-flocculation water outlet according to claim 1, characterized in that, In step e, if the turbulence state is not significantly improved within a 2-4s backwashing cycle, the air pressure ratio between the main air inlet pipe and the auxiliary air inlet pipe is adjusted to 1:(2.5-3.5) or 1:(0.25-0.5) within the pressure limit range.

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