VD rapid degassing process and application equipment

Abstract

The application provides a VD rapid degassing process and application equipment, relates to the field of steel metallurgy, and comprises the following steps: degassing agent preparation and positioning, molten steel treatment and vacuum establishment, air flow guiding, delivery and addition, and deep reaction and system resetting. Through cooperation of the degassing agent and the process steps, a time-delay relay reaction process from "main degassing" to "deep purification" to "secondary stirring" is realized. The composite structure (instantaneous decomposition of the shell, main reaction of the intermediate layer, and delayed activation of the core) of the degassing agent enables the degassing reaction to form a continuous and progressive reaction sequence, significantly prolongs the effective reaction time, ensures that the gas content can be stably and deeply reduced to a very low level, thereby meeting the stringent requirements of high-end steel on the gas content, and improving the stability and consistency of product quality.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgy, and more specifically, to a VD rapid degassing process and its application equipment. Background Technology

[0002] In the steel metallurgy industry, vacuum degassing (VD) is a key refining process for improving steel quality. Its core principle lies in placing a ladle containing molten steel in a vacuum environment. By reducing the partial pressure of the gas phase, the dissolution equilibrium of gases (mainly hydrogen and nitrogen) in the molten steel is disrupted. With the help of the stirring effect generated by blowing in an inert gas (usually argon), the gases diffuse into the bubbles and are quickly removed, thereby significantly improving the purity, toughness, and fatigue resistance of the steel.

[0003] However, the degassing reaction of molten steel in conventional VD processes is often concentrated, intense but short-lived, which can easily lead to problems such as insufficient reaction, low utilization of effective components, and limited ability to remove deep and residual gases. For some high-end steel products, the extremely low gas content standards are difficult to achieve stably with existing processes, which affects the stability and consistency of product quality and limits the competitiveness of enterprises in the high-end steel market.

[0004] Therefore, we have made improvements to this and proposed a rapid VD degassing process and its application equipment. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of poor degassing effect in the current VD process.

[0006] To achieve the above-mentioned objectives and improve the above-mentioned problems, the present invention provides:

[0007] The VD rapid degassing process includes the following steps:

[0008] 1. Degassing agent preparation and placement: Before treatment, a fixed amount of degassing agent is pre-loaded into a sealed storage area isolated from the main treatment chamber;

[0009] 2. Molten steel treatment and vacuum establishment: After sealing the molten steel in the main chamber, a vacuum is drawn until the pressure is below 100 Pa, and inert gas is blown into the bottom of the molten steel for stirring and degassing;

[0010] 3. Airflow guidance and delivery: When the gas content in the molten steel drops to a set threshold, the pipeline connecting the inert gas source and the main chamber is opened. The high-speed airflow formed by the pressure difference pushes the degassing agent in the sealed storage area to the top of the molten steel and blows it into the molten steel.

[0011] 4. Deep reaction and system reset: Maintain vacuum and stirring conditions for deep degassing reaction. After the reaction is completed, restore atmospheric pressure, remove the molten steel, and reset the sealed storage area.

[0012] As a preferred technical solution of this application, in step 3, the high-speed airflow propels the storage body carrying the degassing agent to move along the guide path at a speed of 0.5-1.0 m / s and positions it 0.5-1 meter above the molten steel surface.

[0013] As a preferred technical solution of this application, in step 3, the entire feeding action is completed within 5 seconds.

[0014] As a preferred technical solution of this application, in step 4, the vacuum pressure is maintained below 67 Pa during the deep reaction stage and is continued for 3-5 minutes until the [H] content in the molten steel is ≤1.5 ppm and the [N] content is ≤30 ppm.

[0015] As a preferred technical solution of this application, the degassing agent is a multi-layered composite spherical particle with a particle size of 5-15 mm, comprising, from the inside out:

[0016] Core: A magnesium or aluminum-magnesium alloy matrix encapsulated with a dense alkaline earth metal oxide coating;

[0017] Intermediate layer: a porous structure encapsulating the core, made of calcium-silicon alloy powder, refined slag powder and nano-rare earth oxides;

[0018] Outer shell: a loose structure formed by a mixture of porous carbonized rice husk ash and carbonates that encloses the middle layer.

[0019] As a preferred technical solution of this application, the carbonate in the outer shell is CaCO3 or MgCO3, which decomposes upon contact with molten steel to produce CO2 gas.

[0020] As a preferred technical solution of this application, the thickness of the alkaline earth metal oxide coating of the core is adjusted so that it melts through 30-60 seconds after the degassing agent is added to the molten steel.

[0021] The VD rapid degassing application device, as a preferred technical solution of this application, includes a vacuum chamber, a support component inside the vacuum chamber, a venting component at the bottom of the support component, a docking component outside the venting component, a connecting component at the bottom inside the vacuum chamber, a limiting component at the top of the connecting component, an installation component on one side of the vacuum chamber, and a pre-storage component inside the installation component.

[0022] As a preferred technical solution of this application, the bearing component includes a bearing cylinder, and the bottom end of the bearing cylinder is provided with a plurality of installation ports; the ventilating component includes ventilating bricks fixed inside the installation ports.

[0023] As a preferred technical solution of this application, the installation component includes a connecting cylinder, which is fixed to the outside of the vacuum chamber. A blocking cylinder is fixed inside the connecting cylinder on the side near the vacuum chamber, and one end of the blocking cylinder extends through the vacuum chamber into the interior of the vacuum chamber.

[0024] The pre-storage component includes a pre-storage cylinder slidably connected inside the blocking cylinder. A blocking ring is fixedly provided on the side of the pre-storage cylinder away from the bearing component. The blocking ring is slidably connected to the inside of the connecting cylinder. A buffer is provided on the side of the blocking ring near the bearing component. Several limiting components are provided inside the pre-storage cylinder.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] In the scheme of this application:

[0027] 1. By coordinating the degassing agent with the process steps, a delayed relay reaction process from "main degassing" to "deep purification" and then to "secondary stirring" is achieved. The composite structure of the degassing agent (instantaneous decomposition of the outer shell, main reaction of the middle layer, and delayed activation of the core) enables the degassing reaction to form a continuous and progressive reaction sequence, significantly extending the effective reaction time and ensuring that the gas content can be stably and deeply reduced to extremely low levels (such as [H]≤1.5 ppm), thereby meeting the stringent requirements of high-end steel for gas content, improving the stability and consistency of product quality, and solving the problems of poor degassing effect, concentrated, short and insufficient degassing reaction, and limited ability to remove deep and residual gases in the existing VD process.

[0028] 2. By setting up the "precise material delivery and addition under airflow guidance" step, the degassing agent can be automatically, quickly and accurately added within 5 seconds without disrupting the main vacuum environment. Utilizing the inherent pressure difference of the system as the driving force, the feeding action is simplified into a pure airflow control logic, which effectively shortens the auxiliary operation time and significantly shortens the VD smelting cycle. This directly improves the production rhythm and overall efficiency, and solves the problems of complex equipment, time-consuming operation, easy interruption of vacuum and production rhythm in the traditional feeding method of the existing technology. At the same time, it affects the closing of the vacuum container lid and the entry and exit of molten steel into and out of the vacuum container.

[0029] 3. By using the "instantaneous aerodynamic dispersion" of the degassing agent shell and the secondary boiling effect generated by the core, the microbubbles generated by the decomposition of the shell and the violent boiling caused by the rise of magnesium vapor in the core are achieved, forming additional spontaneous stirring energy from inside the molten steel. This, in conjunction with bottom blowing argon stirring, makes the composition and temperature of the molten steel more uniform and promotes the collision, growth and floating removal of degassing products and fine inclusions. This solves the problems of stirring "dead zone" and insufficient floating efficiency of inclusions that may exist in the existing technology that relies solely on bottom blowing argon.

[0030] 4. By setting up the "degassing agent preparation and placement" and "molten steel treatment and vacuum establishment" steps, a simple and reliable storage body reset and refilling mechanism based on real-time data is realized, which ensures the stability of the process between each heat, reduces the impact of human factors on product quality, and solves the problems of reliance on manual experience and poor operational consistency in the traditional process of the existing technology. Attached Figure Description

[0031] Figure 1 A process flow diagram of the VD rapid degassing process provided in this application;

[0032] Figure 2 A process flow diagram of step 1 in the VD rapid degassing process provided in this application;

[0033] Figure 3 A process flow diagram of step 2 in the VD rapid degassing process provided in this application;

[0034] Figure 4 A process flow diagram of step 3 in the VD rapid degassing process provided in this application;

[0035] Figure 5 The process flow diagram for step 4 of the VD rapid degassing process provided in this application;

[0036] Figure 6 A schematic diagram of the VD rapid degassing application equipment provided in this application;

[0037] Figure 7 A schematic diagram showing the disassembled structure of the air-permeable component in the VD rapid degassing application device provided in this application;

[0038] Figure 8 A schematic diagram of the limiting component in the VD rapid degassing application device provided in this application;

[0039] Figure 9 A schematic diagram showing the disassembled structure of the pre-stored components in the VD rapid degassing application device provided in this application.

[0040] The image shows:

[0041] 1. Vacuum chamber; 11. Fixed tube; 12. Chamber cover; 2. Bearing assembly; 21. Bearing cylinder; 22. Fixed column; 3. Ventilation assembly; 31. Mounting port; 32. Ventilation brick; 4. Connecting assembly; 41. Connecting cylinder; 42. No. 1 sealing ring; 43. Connecting cylinder; 44. Limiting cylinder; 5. Connecting assembly; 51. Buffer cylinder; 52. Support plate; 53. Connecting tube; 6. Limiting assembly; 61. Mounting ring; 62. Support ring; 63. Connecting ring; 7. Mounting assembly; 71. Connecting cylinder; 72. Blocking cylinder; 73. Exhaust groove; 8. Pre-storage assembly; 81. Pre-storage cylinder; 82. Blocking ring; 83. No. 2 sealing ring; 84. Restriction ring. Detailed Implementation

[0042] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0043] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0044] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] Example 1

[0047] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 The VD rapid degassing process includes the following steps:

[0048] 1. Preparation and placement of degassing agent: Before treatment, a quantitative amount of high-efficiency degassing agent is pre-loaded into a sealed storage area isolated from the main treatment chamber;

[0049] II. Molten Steel Treatment and Vacuum Establishment: After sealing the molten steel in the main chamber, evacuate the vacuum to a pressure below 100 Pa, and blow inert gas (such as argon) into the bottom of the molten steel for stirring and degassing;

[0050] 3. Airflow guidance and delivery: When the gas content in the molten steel drops to a set threshold, the pipeline connecting the inert gas source and the main chamber is opened. The high-speed airflow formed by the pressure difference pushes the degassing agent in the sealed storage area to the top of the molten steel and blows it into the molten steel.

[0051] IV. Deep Reaction and System Reset: Maintain vacuum and stirring conditions for deep degassing reaction. After the reaction is completed, restore atmospheric pressure, remove the molten steel, and reset the sealed storage area.

[0052] Furthermore, such as Figure 1 , Figure 2 and Figure 5 As shown, the degassing agent is prepared and positioned:

[0053] Before the molten steel enters the main processing system, the degassing agent is prepared. The metered, high-efficiency degassing agent is pre-loaded into a dedicated, sealed storage area. This storage area operates in two states: during the preparation and standby phases, it is completely isolated from the main processing chamber, maintaining an inert environment to ensure the chemical activity of the degassing agent is not disturbed by external factors before addition. Its internal structure keeps the material in a stable, aggregated state, preventing leakage or performance degradation due to equipment movement or vibration. This step moves the complex weighing and feeding operations, which would normally require a vacuum, to an atmospheric pressure environment, transporting the material to the physical location closest to the final addition point. Once this step is completed, the system is in a ready state, and its output points to the trigger signal for the third step.

[0054] Furthermore, such as Figure 1 and Figure 3 As shown, molten steel treatment and vacuum establishment:

[0055] After the container filled with molten steel is sent into the main chamber and sealed, it immediately enters the stage of rapidly establishing a vacuum, quickly extracting the gas in the chamber, so that the ambient pressure drops from atmospheric pressure to the high vacuum range set by the process (for example, to below several hundred Pascals). This process of rapid pressure drop is itself the initial driving force for degassing. According to Sivarti's law of gas dissolution, the solubility of a gas in molten metal is proportional to the square root of its partial pressure on the surface of the molten metal. The formula can be simplified as: [S]=K*√p, where [S] is the gas solubility, K is the equilibrium constant, and p is the partial pressure of the gas phase.

[0056] Therefore, when the total pressure of the chamber (and the partial pressures of hydrogen and nitrogen) is drastically reduced, the equilibrium state of hydrogen and nitrogen atoms dissolved in the molten steel is broken, and they gain a strong thermodynamic driving force to escape into the gas phase.

[0057] Once the vacuum is established, the physical degassing process is initiated: a controlled inert gas flow is continuously introduced into the bottom of the molten steel. After entering the molten steel, this gas flow expands rapidly in the vacuum environment, forming an upward-flowing bubble flow.

[0058] These bubbles produce a dual effect during their ascent: firstly, a strong fluid stirring effect, which rapidly homogenizes the composition and temperature inside the molten steel; and secondly, a carrier effect for gas transport.

[0059] Hydrogen and nitrogen atoms dissolved in molten steel diffuse to the bubble interface, combine into molecules, and enter the bubble. They are then carried directly to the vacuum space by the rising bubbles and eventually pumped away. This step "creates pressure difference driving force" and "provides an efficient material transport channel," constituting a rapid degassing process. Its effectiveness (feedback from real-time monitoring of gas content, pressure, and other parameters) determines whether and when the third step is needed to trigger deep chemical degassing.

[0060] Furthermore, such as Figure 1 and Figure 4 As shown, material delivery and addition guided by airflow:

[0061] When the real-time monitoring system in the second step (such as a mass spectrometer or laser gas analyzer) determines that the residual gas content in the molten steel has dropped to a specific threshold (e.g., [H] is between 1.5 and 2.0 ppm, or the degassing rate slows down significantly), the serialization command in this step is triggered. A pre-established controllable differential pressure channel is used to automate the material transport. Specifically, a dedicated path valve connecting the inert gas source and the main vacuum chamber is opened. Because the pressure on the gas source side (typically 0.4-0.6 MPa) is much higher than the vacuum pressure inside the chamber (typically <100 Pa), a high-speed directional airflow is generated according to fluid dynamics principles. Its volumetric flow rate Q can be estimated by the simplified flow equation Q=C*A*√(2ΔP / ρ)°, where C is the flow coefficient, A is the pipe area, ΔP is the pressure difference, and ρ is the gas density. This high-speed airflow acts as the power medium.

[0062] Meanwhile, the storage container, carrying the pre-prepared quantitative degassing agent from the first step, can be unlocked in this specific airflow field. The airflow force overcomes the initial static friction of the storage container, propelling it smoothly into the main chamber at a controlled speed (e.g., 0.5-1.0 m / s) along a guide path, and finally precisely positioning it at the addition position above the molten steel pool (usually 0.5-1 meter above the liquid surface). After positioning, the airflow does not stop. Through the change in flow channel design inside the storage container, it directly acts on the degassing agent inside, causing it to be uniformly and diffusely blown into the molten steel in the form of fluidization or spraying. This step transforms the feeding action from the traditional mode that relies on complex robotic arms or manual intervention into an automated process purely controlled by airflow logic. The feeding action itself can be completed within 5 seconds, hardly occupying any additional smelting cycle. It utilizes the pressure environment (the difference between the low pressure at the vacuum end and the positive pressure at the gas source end) to convert into driving force to achieve automatic feeding. This not only simplifies the equipment structure and improves reliability, but also avoids the sealing and maintenance problems caused by the introduction of additional moving parts.

[0063] Furthermore, such as Figure 1 , Figure 2 and Figure 5 As shown, deep reaction and system state reset:

[0064] After the degassing agent is added to the molten steel, the process enters the deep purification stage. The main system continues to maintain a high vacuum environment (e.g., pressure maintained below 67 Pa) and bottom blowing agitation to create kinetic conditions for the chemical reaction between the degassing agent and residual elements such as [H], [N], and [O] in the molten steel. The chemical reaction at this stage is the key to rapid degassing. Taking calcium-based degassing agents as an example, its main reaction can be described as follows:

[0065] Ca(l / g) + [H] → CaH2(s), 3Ca(l / g) + 2[N] → Ca3N2(s), and the strong deoxygenation reaction Ca + [O] → CaO(s);

[0066] The solid products generated by these reactions will float into the slag layer. Continuous stirring not only accelerates the mass transfer process of the reactants, but also promotes the collision, aggregation and flotation removal of these inclusions. This deep reaction stage usually lasts for 3-5 minutes until the monitoring system confirms that the gas content has stabilized and reached the final target value (e.g., [H]≤1.5ppm, [N]≤30ppm).

[0067] After the reaction is complete, the system enters the reset phase: First, the main vacuum system stops pumping and refills the chamber with inert gas to atmospheric pressure; then, the seal is opened, and at the same time, the empty storage tank that has completed its feeding task is hooked by a simple "L"-shaped tool and pushed back to the initial position in the chamber, ensuring that it does not obstruct the removal of molten steel. The processed molten steel is then removed and enters the subsequent continuous casting process; here, the storage tank can be easily opened to remove any remaining small amount of reaction products and refilled with the degassing agent required for the next heat, returning to the preparatory state. This step ensures the efficient and continuous operation of the entire process.

[0068] Example 2

[0069] The VD rapid degassing process provided in Example 1 is further optimized, specifically, as follows: Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the degassing agent is a multi-layered composite spherical particle with its particle size strictly controlled within a certain range (e.g., 5-15 mm) to ensure good flowability and trajectory stability during airflow delivery. It consists of three layers from the inside out and is prepared using powder metallurgy and granulation processes.

[0070] 1. Core (Activation Delayed Reaction Core):

[0071] Main components: Magnesium (Mg) or aluminum-magnesium (Al-Mg) alloy powder in a specific ratio is used as the matrix, and a thin and dense alkaline earth metal oxide (such as CaO) coating is uniformly wrapped on the outside. This coating is attached by a special sol-gel process and the thickness is precisely controlled.

[0072] Key to preparation: By adjusting the coating composition (such as adding a small amount of SiO2) and thickness, the melting delay time in molten steel can be precisely controlled (for example, the goal is to start melting through 30-60 seconds after addition).

[0073] 2. Intermediate layer (main degassing reaction layer):

[0074] Main components: This is the main body of the degassing agent, which is uniformly mixed with high-purity calcium silicon (CaSi) alloy powder, refined slag powder (main components are CaO-Al2O3-SiO2) and trace amounts of rare earth oxides (such as CeO2, La2O3), and then molded under high pressure and wrapped around the core.

[0075] Key preparation steps: Isostatic pressing is employed to ensure the layer possesses sufficient mechanical strength to withstand delivery impacts, while maintaining approximately 30% porosity to guarantee air permeability. Rare earth oxides exist in a nanoscale dispersed phase.

[0076] 3. Outer shell (instantaneous aerodynamic dispersion and insulation layer):

[0077] Main composition: It is made of porous carbonized rice husk ash mixed with specific carbonates (such as CaCO3 or MgCO3) in a certain proportion and formed by low temperature binder; this layer is more porous than the core and middle layer, with lower bulk density and higher specific surface area.

[0078] Key to preparation: Controlling its pore structure so that it can decompose and produce gas rapidly at high temperatures without breaking down prematurely.

[0079] The three-layer structure of this degassing agent works in conjunction with the aforementioned process steps:

[0080] 1. Regarding "material delivery and addition guided by airflow," its spherical outer shell provides excellent aerodynamic characteristics, ensuring stable flight in high-speed airflow and precise landing in the designated area of ​​molten steel. At the moment of contact between the outer shell and the molten steel, its porous carbonate components undergo a violent decomposition reaction at high temperature.

[0081] CaCO3(s)→CaO(s)+CO2(g)↑ (rapid, ~ 1100°C)

[0082] The large amount of CO2 gas generated instantaneously forms a local "micro-gas curtain". On the one hand, it achieves primary physical dispersion, effectively preventing the particle group from sticking together or being immediately encased and floated by the molten steel, forcing it to immerse. On the other hand, the endothermic decomposition reaction (ΔH>0) forms a short-term micro-cooling zone around the particles, slightly delaying the overall melting of the outer shell and buying valuable time for the particles to be fully immersed in the molten steel.

[0083] 2. In conjunction with "deep reaction and system state reset," the intermediate layer reacts first: the loose and porous main reaction layer is rapidly penetrated by molten steel and heated to the reaction temperature; the highly active CaSi alloy melts and vaporizes, releasing calcium vapor (Ca↑), whose chemical reaction with [H], [N], and [O] in the molten steel is the core of deep degassing.

[0084] [H]+Ca(g)→CaH2(s), 2[N]+3Ca(g)→Ca3N2(s), [O]+Ca(g)→CaO(s)

[0085] Meanwhile, the dispersed nano-rare earth oxides become heterogeneous nucleation cores for fine inclusions (such as Al2O3 and SiO2), promoting their collision growth and flotation removal through adsorption.

[0086] As the main reaction progresses to a certain point, heat transfer from the outer layer eventually melts through the dense oxide coating of the core, exposing the internal Mg or Al-Mg alloy, which has a lower boiling point (Mg boiling point...). ~At 1090°C, magnesium vapor (Mg↑) rapidly vaporizes at the temperature of molten steel. At this time, the oxygen activity of the molten steel has been significantly reduced after the previous degassing. The Mg vapor plays two main roles: first, as a strong reducing agent, it sweeps away residual oxygen and sulfur; second, its violent upward floating brings a secondary boiling effect, which strongly stirs the molten steel and further promotes the upward floating of the solid desulfurization, deoxidation and degassing products generated in the previous stage. It is equivalent to having an automatic process strengthening pulse built in.

[0087] Traditional degassing agents typically involve a single, violent reaction. This solution, through delayed activation of the core, achieves a three-stage relay reaction of "main degassing - deep purification - secondary stirring." This not only significantly extends the effective reaction time window, but also provides new driving force when the main reaction slows down, effectively avoiding the problem of insufficient power at the end of the reaction. This ensures that the gas content can be stably and deeply reduced to an extremely low level within the set treatment time, an effect that is difficult to achieve with traditional single-phase degassing agents.

[0088] The decomposition and gas generation in the outer shell is not only a dispersion method, but the tiny bubbles it produces also provide additional non-contact micro-stirring for the molten steel in the initial stage. Furthermore, the magnesium vapor boiling that is ultimately generated in the core is a spontaneously generated and uniformly distributed stirring energy from deep within the ladle. Compared to macroscopic stirring that relies solely on bottom argon blowing, this endogenous stirring from the micro to the mesoscopic level is more effective in breaking up "dead zones," thereby improving the efficiency of composition and temperature homogenization and inclusion removal by approximately 15-25%.

[0089] The CaO produced by the decomposition of the outer shell, the MgO produced by the reaction of the core, and the refining slag components in the main reaction layer together form a layer of active refining slag with high alkalinity and good adsorption capacity on the surface of the molten steel. This slag layer can effectively absorb the floating degassing products (such as CaH2 and Ca3N2) and inclusions, prevent them from dissolving back, and achieve partial synergy between degassing and soft blowing refining, thereby improving the purity of the molten steel.

[0090] Example 3

[0091] Please refer to Figure 6 , Figure 7 , Figure 8 and Figure 9 The VD rapid degassing application equipment includes a vacuum chamber 1. A fixed tube 11 is fixedly provided on the outside of the vacuum chamber 1. One end of the fixed tube 11 passes through the vacuum chamber 1 and communicates with the inside of the vacuum chamber 1. The other end of the fixed tube 11 is connected to a vacuum pump. A chamber cover 12 is provided at the top of the vacuum chamber 1. The chamber cover 12 is placed on the top of the vacuum chamber 1 to seal it. Then the vacuum pump is started to make the inside of the vacuum chamber 1 a vacuum state.

[0092] The vacuum chamber 1 is equipped with a bearing component 2 inside, which is used to load molten steel. The bottom of the bearing component 2 is equipped with a venting component 3, through which gas enters the interior of the bearing component 2. The outside of the venting component 3 is equipped with a docking component 4, which is used to ensure the airtightness of argon gas entering the interior of the bearing component 2 through the venting component 3. The bottom of the vacuum chamber 1 is equipped with a connecting component 5, which can be used to buffer inert gas when the vacuum pump is drawing a vacuum. The top of the connecting component 5 is equipped with a limiting component 6, which is located between the connecting component 5 and the bearing component 2. The side of the vacuum chamber 1 is equipped with an installation component 7, which is equipped with a pre-storage component 8 inside. The pre-storage component 8 is used to pre-store degassing agent and to introduce degassing agent into the molten steel through gas flow.

[0093] Furthermore, such as Figure 6 , Figure 7 and Figure 8 As shown, the bearing assembly 2 includes a bearing cylinder 21, which includes, but is not limited to, a steel ladle. Two fixed posts 22 are fixedly provided on both sides of the bearing cylinder 21. The two fixed posts 22 are used to be hooked by the two hooks of a crane or hoist, and then the bearing cylinder 21 is pulled upwards for transport. Several installation ports 31 communicating with the interior of the bearing cylinder 21 are provided at the bottom end of the bearing cylinder 21. The venting assembly 3 includes a venting brick 32 fixed inside the installation ports 31. The porous venting structure of the venting brick 32 prevents molten steel from passing through the venting brick 32, but allows gas to pass through it.

[0094] The buffer cylinder 51 includes a buffer cylinder 51 fixed to the bottom of the vacuum chamber 1. A support plate 52 is fixed to the top of the buffer cylinder 51. A connecting pipe 53 is fixed to one side of the buffer cylinder 51. One end of the connecting pipe 53 passes through the buffer cylinder 51 and extends into the interior of the buffer cylinder 51. The other end of the connecting pipe 53 passes through the vacuum chamber 1 and is connected to an inert gas source. The inert gas is argon. When it is necessary to allow argon to enter the interior of the buffer cylinder 51, the valve is opened and the gas pump is started, so that the argon is pressurized by the gas pump and enters the interior of the buffer cylinder 51. The pressure inside the buffer cylinder 51 increases, so that the argon passes through the connecting cylinder 43 and the permeable brick 32 and comes into contact with the molten steel inside the vacuum chamber 1 to react.

[0095] The limiting component 6 includes a connecting ring 63 fixed to the top of the support plate 52, a connecting ring 63 inside the mounting ring 61, a connecting ring 63 outside the mounting ring 61, a support ring 62 and a connecting ring 63 both fixedly connected to the bottom end of the bearing cylinder 21, and a docking component 4 located inside the support ring 62.

[0096] The docking assembly 4 includes a docking cylinder 41 located below the mounting port 31. The docking cylinder 41 is fixedly connected to the bottom end of the bearing cylinder 21. A first sealing ring 42 is fixedly provided at the bottom end of the docking cylinder 41. The first sealing ring 42 is used to achieve a sealing effect. A connecting cylinder 43 is provided inside the docking cylinder 41. The bottom end of the connecting cylinder 43 passes through the support plate 52 and communicates with the inside of the buffer cylinder 51. A limiting cylinder 44 is provided outside the docking cylinder 41. Both the connecting cylinder 43 and the limiting cylinder 44 are fixedly connected to the top end of the support plate 52.

[0097] Furthermore, such as Figure 6 and Figure 9 As shown, the mounting assembly 7 includes a connecting cylinder 71. A control valve is located at the end of the connecting cylinder 71 furthest from the supporting assembly 2. The output end of the control valve is connected to the connecting cylinder 71, and the input end of the control valve is connected to an inert gas source via a pipe. Connecting to the inert gas source and then to the inside of the vacuum chamber 1 avoids the entry of foreign objects into the vacuum chamber 1, preventing issues that could affect the degassing effect. The connecting cylinder 71 is fixed to the outside of the vacuum chamber 1, positioned above the supporting cylinder 21. A blocking cylinder 72 is fixed inside the connecting cylinder 71 on the side closest to the vacuum chamber 1. The blocking cylinder 72 is located at the end near the supporting assembly 2. A slide gate valve is provided to close the end of the blocking cylinder 72 near the support component 2. When it is necessary for the pre-storage component 8 to slide out of the blocking cylinder 72, the slide gate valve is opened to open the end of the blocking cylinder 72 near the support component 2, allowing the pre-storage cylinder 81 to slide out. One end of the blocking cylinder 72 extends through the vacuum chamber 1 into the interior of the vacuum chamber 1. Several exhaust grooves 73 are provided on the inner wall of the blocking cylinder 72. The exhaust grooves 73 are used to allow the gas between the blocking cylinder 72 and the blocking ring 82 to be discharged when the blocking ring 82 and the pre-storage cylinder 81 move, so as to avoid affecting the movement of the blocking ring 82 and the pre-storage cylinder 81.

[0098] The pre-storage component 8 includes a pre-storage cylinder 81 that is slidably connected inside the blocking cylinder 72. When the valve on the connecting cylinder 71 is opened, the airflow collides with the blocking ring 82, thereby pushing the pre-storage cylinder 81 to move. The blocking ring 82 is fixedly provided on the side of the pre-storage cylinder 81 away from the bearing component 2. The inner radius of the blocking ring 82 is smaller than the inner radius of the connecting cylinder 71, so that when the airflow passes through, it will collide with the blocking ring 82 and push the blocking ring 82 and the pre-storage cylinder 81 to move. The blocking ring 82 is slidably connected to the inside of the connecting cylinder 71.

[0099] Example 4

[0100] The VD rapid degassing application equipment provided in Example 3 has been further optimized, specifically, as follows: Figure 6 and Figure 9 As shown, the blocking ring 82 has a buffer on the side near the bearing assembly 2, and the pre-storage cylinder 81 has several limiting components inside;

[0101] The buffer includes a second sealing ring 83 fixedly connected to the blocking ring 82. The second sealing ring 83 and the first sealing ring 42 are made of rubber, including but not limited to rubber. The second sealing ring 83 can buffer when it collides with the blocking cylinder 72, and at the same time seal the exhaust groove 73, so that the airflow is concentrated inside the blocking ring 82 and passes through to the inside of the pre-storage cylinder 81, while preventing too much gas from entering the vacuum chamber 1. The second sealing ring 83 is located outside the pre-storage cylinder 81 and does not contact the connecting cylinder 71.

[0102] The limiting component includes a limiting ring 84, which is used to block the degassing agent and increase the airflow resistance, so that the airflow can better pass through the blocking of the limiting ring 84 to drive the pre-storage cylinder 81 to move. It works with the blocking ring 82 to push the pre-storage cylinder 81 out. Several limiting rings 84 are fixed at equal intervals inside the pre-storage cylinder 81. An inclined surface is opened on the side of the limiting ring 84 away from the bearing component 2. The inclined surface is used to allow the degassing agent to easily pass over the limiting ring 84.

[0103] The usage process of the VD rapid degassing process and application equipment provided by this invention is as follows:

[0104] When it is necessary to degas the molten steel inside the bearing cylinder 21, the degassing agent is placed inside the pre-storage cylinder 81 and restricted by the limiting ring 84. Then, the slide valve on the blocking cylinder 72 is closed, and the bearing cylinder 21 is lifted by hooking the fixed columns 22 on both sides of the bearing cylinder 21 with the hook of the crane or hoist. Then, the bearing cylinder 21 is placed inside the vacuum chamber 1, and the docking cylinder 41 is docked between the connecting cylinder 43 and the limiting cylinder 44. It is sealed by the first sealing ring 42, and then the chamber cover 12 is covered to seal it, so that the vacuum chamber 1 is isolated from the outside. Then, the vacuum pump is started, and the gas inside the vacuum chamber 1 is extracted through the fixed pipe 11. At this time, the valve controlling the inert gas to flow into the buffer cylinder 51 is opened and the air pump is started. The inert gas is injected into the buffer cylinder 51 through the connecting pipe 53 for pre-storage by the air pump. Then, the air pump and the valve are closed. At this time, the air pressure is insufficient to allow the inert gas to pass through the permeable brick 32.

[0105] When the air pressure inside the vacuum chamber 1 is at the low pressure threshold of the specified range, the air pump that controls the inert gas to flow into the buffer cylinder 51 is started, so that the inert gas passes through the permeable brick 32 under high pressure and comes into contact with the molten steel inside the bearing cylinder 21. After entering the molten steel, the volume of the inert gas expands rapidly in the vacuum environment, forming an upward surging bubble flow. At the same time, the surging of the bubbles stirs the molten steel. The hydrogen and nitrogen atoms dissolved in the molten steel diffuse to the bubble interface, combine into molecules and enter the bubble. Then they are directly carried to the vacuum space by the rising bubbles and are finally pumped away.

[0106] When the gas content in the molten steel decreases to a specified threshold, the control valve on the connecting cylinder 71 is opened, and then the gate valve on the blocking cylinder 72 is opened. This allows the inert gas to be rapidly drawn into the vacuum chamber 1 due to the low pressure inside the vacuum chamber 1. When the airflow passes through the blocking ring 82, due to the small space inside the blocking ring 82, most of the airflow impacts the blocking ring 82 and pushes the blocking ring 82 and the pre-storage cylinder 81 to extend. The extension stops after the second sealing ring 83 contacts the blocking cylinder 72, so that the end of the pre-storage cylinder 81 is above the bearing cylinder 21. The exhaust groove 73 is blocked by the second sealing ring 83, and a large amount of gas begins to rush into the interior of the pre-storage cylinder 81, which drives the degassing agent inside the pre-storage cylinder 81 outward. As a result, the path of the degassing agent is too close to the surface of the molten steel inside the bearing cylinder 21, so that it is sprinkled on the molten steel and merges with the molten steel. The degassing agent further degasses the molten steel.

[0107] After degassing is completed, the pressure inside the vacuum chamber 1 is released, and then the chamber cover 12 is opened. An L-shaped long rod tool can be used to hook the end of the pre-storage cylinder 81 and pull it into the connecting cylinder 71, so that it returns to the inside of the connecting cylinder 71 and the blocking cylinder 72. Then, the carrying cylinder 21 is separated from the inside of the vacuum chamber 1 by a crane or hoist.

[0108] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0109] Obviously, the embodiments described above are merely some embodiments of the present invention, not all embodiments. The accompanying drawings show preferred embodiments of the present invention, but do not limit the patent scope of the present invention. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. A VD rapid degassing process, characterized in that, Includes the following steps: (1) Preparation and placement of degassing agent: Before treatment, a quantitative amount of degassing agent is preloaded into a sealed storage area isolated from the main treatment chamber; (2) Steel treatment and vacuum establishment: After sealing the molten steel in the main chamber, vacuum is drawn until the pressure is below 100 Pa, and inert gas is blown into the bottom of the molten steel for stirring and degassing; (3) Airflow guidance delivery and addition: When the gas content in the molten steel is detected to drop to the set threshold, the pipeline connecting the inert gas source and the main chamber is opened, and the high-speed airflow formed by the pressure difference is used to push the degassing agent in the sealed storage area to the top of the molten steel and blow it into the molten steel. (4) Deep reaction and system reset: Maintain vacuum and stirring conditions for deep degassing reaction. After the reaction is completed, restore normal pressure, remove molten steel, and reset the sealed storage area.

2. The VD rapid degassing process according to claim 1, characterized in that, In step (3), the high-speed airflow propels the storage body carrying the degassing agent to move along the guide path at a speed of 0.5-1.0 m / s and positions it 0.5-1 meter above the molten steel surface.

3. The VD rapid degassing process according to claim 1, characterized in that, In step (3), the entire feeding action is completed within 5 seconds.

4. The VD rapid degassing process according to claim 1, characterized in that, In step (4), the vacuum pressure is maintained below 67 Pa during the deep reaction stage and is continued for 3-5 minutes until the [H] content in the molten steel is ≤1.5 ppm and the [N] content is ≤30 ppm.

5. The VD rapid degassing process according to claim 1 or 2, characterized in that, The degassing agent is a multi-layered composite spherical particle with a particle size of 5-15 mm, comprising, from the inside out: Core: A magnesium or aluminum-magnesium alloy matrix encapsulated with a dense alkaline earth metal oxide coating; Intermediate layer: a porous structure encapsulating the core, made of calcium-silicon alloy powder, refined slag powder and nano-rare earth oxides; Outer shell: a loose structure formed by a mixture of porous carbonized rice husk ash and carbonates that encloses the middle layer.

6. The VD rapid degassing process according to claim 5, characterized in that, The carbonate in the outer shell is CaCO3 or MgCO3, which decomposes upon contact with molten steel to produce CO2 gas.

7. The VD rapid degassing process according to claim 5, characterized in that, The thickness of the alkaline earth metal oxide coating in the core is controlled so that it melts through 30-60 seconds after the degassing agent is added to the molten steel.

8. A VD rapid degassing application device, using the VD rapid degassing process as described in claim 1, characterized in that, The vacuum chamber (1) includes a support component (2) inside the vacuum chamber (1), a breathable component (3) at the bottom of the support component (2), a docking component (4) outside the breathable component (3), a connecting component (5) at the bottom inside the vacuum chamber (1), a limiting component (6) at the top of the connecting component (5), an installation component (7) on one side of the vacuum chamber (1), and a pre-storage component (8) inside the installation component (7).

9. The VD rapid degassing application equipment according to claim 8, characterized in that, The bearing component (2) includes a bearing cylinder (21), and the bottom end of the bearing cylinder (21) is provided with a plurality of mounting ports (31); the air-permeable component (3) includes an air-permeable brick (32) fixed inside the mounting port (31).

10. The VD rapid degassing application device according to claim 8 or 9, characterized in that, The mounting assembly (7) includes a connecting cylinder (71), which is fixed to the outside of the vacuum chamber (1). A blocking cylinder (72) is fixed inside the connecting cylinder (71) on the side close to the vacuum chamber (1). One end of the blocking cylinder (72) extends through the vacuum chamber (1) into the interior of the vacuum chamber (1). The pre-storage component (8) includes a pre-storage cylinder (81) slidably connected inside the blocking cylinder (72). A blocking ring (82) is fixedly provided on the side of the pre-storage cylinder (81) away from the bearing component (2). The blocking ring (82) is slidably connected to the inside of the connecting cylinder (71). A buffer is provided on the side of the blocking ring (82) close to the bearing component (2). Several limiting components are provided inside the pre-storage cylinder (81).

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