Rh vacuum refining device and refining method

Abstract

The application discloses an RH vacuum refining device and a refining method, and belongs to the technical field of RH vacuum refining of steel smelting. The device comprises a ladle, a driving mechanism, an air gun, a detection mechanism and a control mechanism; the driving mechanism is arranged above the ladle and connected with the air gun, and is used for driving the air gun to extend into molten steel; the detection mechanism is arranged above the ladle and used for detecting the state of a slag surface; and the control mechanism is electrically connected with the detection mechanism and the driving mechanism. The refining method forms an initial slag-free area by bottom blowing gas, drives away residual slag by air gun blowing, and after the slag-free state is determined in real time by the detection mechanism, the control mechanism is linked to perform ladle jacking and air gun avoidance, and then vacuum refining is completed. The application can improve the slag-free determination precision and the equipment linkage efficiency, reduce the pollution of the slag to the molten steel, and improve the refining automation level.

Description

Technical Field

[0001] This application belongs to the field of RH vacuum refining technology in iron and steel smelting, and particularly relates to an RH vacuum refining apparatus and refining method. Background Technology

[0002] RH vacuum refining is a core process in the production of high-quality steel. Through the circulation and composition control of molten steel in a vacuum environment, harmful gases and non-metallic inclusions in the steel can be removed. It is a necessary step in the production of high value-added products such as low-carbon steel and ultra-low-carbon steel.

[0003] In actual production, slag in the ladle is easily drawn into the molten steel during stirring and circulation, causing secondary pollution and directly reducing the purity of the steel, thus affecting the quality of the final steel product. Current production relies heavily on manual visual observation of the slag surface, which has a large margin of error and cannot accurately identify the formation of slag-free areas. Furthermore, the observation results depend on the operator's experience, making it difficult to standardize judgment criteria across different heats and resulting in insufficient stability.

[0004] Meanwhile, the determination of slag surface condition is independent of the operation of refining equipment, requiring manual control of ladle lifting and adjustment of immersion tube depth. This results in a significant delay in operational response, lowering overall production efficiency and potentially disrupting established slag-free areas due to timing errors, further weakening the refining effect. These issues restrict the production qualification rate and process efficiency of high-quality steel, making it difficult to meet the demands of large-scale, intelligent production. Summary of the Invention

[0005] This application aims to at least partially solve the technical problems of low accuracy in slag-free refining judgment and poor equipment operation linkage, which lead to inconvenience in use. To this end, this application provides an RH vacuum refining apparatus and refining method.

[0006] In a first aspect, embodiments of this application provide an RH vacuum refining apparatus, comprising: a ladle for holding molten steel; a drive mechanism disposed above the ladle; an air gun connected to the drive mechanism, the drive mechanism being used to drive the air gun to extend into the molten steel; a detection mechanism disposed above the ladle; and a control mechanism electrically connected to both the detection mechanism and the drive mechanism.

[0007] Therefore, the detection agency can obtain the slag surface status in real time, replacing manual visual observation and eliminating the errors and delays of human observation. The control mechanism directly controls the drive mechanism based on the detection signals, eliminating the need for manual intervention, resulting in a faster response speed. It can complete the air gun action switch at the optimal time when the slag-free zone is formed, avoiding operational delays that could lead to slag re-diffusion. The air gun can actively extend into the molten steel to act on the slag layer. Compared with relying solely on the natural flow of molten steel to drive away slag, the effect of driving away residual slag is more direct and more stable.

[0008] In one possible implementation, the driving mechanism includes a rotating mechanism and a lifting mechanism. The rotating mechanism drives the air gun to rotate horizontally into or out of the ladle, while the lifting mechanism drives the air gun to move vertically up and down. Thus, the rotating mechanism enables the air gun to switch positions, rotating it into the ladle during slag removal operations and outwards during vacuum refining, avoiding structural interference between the air gun and the descending immersion tube and ensuring smooth process transitions. The lifting mechanism independently controls the immersion depth, flexibly adjusting the purging position according to the slag layer thickness and molten steel level, ensuring the airflow from the air gun always acts at the optimal slag removal depth, guaranteeing effective slag removal.

[0009] In one possible implementation, the RH vacuum refining apparatus includes a permeable brick and a gas pipeline. The permeable brick is embedded in the bottom of the ladle, and the gas pipeline is connected to the permeable brick. Gas is thus blown upwards from the center of the ladle's bottom, and the rising airflow carries the molten steel in the center upwards, thereby pushing the slag covering the surface to diffuse around the ladle, forming a slag-free zone in the center of the ladle.

[0010] In one possible implementation, there are multiple permeable bricks, all of which are circular. Thus, when multiple permeable bricks are evenly arranged along the center, the superimposed airflow forms a larger and more uniform upward flow field, which can more quickly blow away the central slag, and the resulting slag-free area has a more regular boundary, reducing local slag residue.

[0011] In one possible implementation, the gas in the air gun and the gas pipeline is either argon or carbon dioxide. This allows the device to be adapted to the process requirements of more steel grades, thus broadening its applicability.

[0012] In one possible implementation, the nozzle of the air gun is made of refractory material and is inclined towards the edge of the ladle at an angle of 30° to 60°. The nozzle can be immersed 50 mm to 150 mm below the surface of the molten steel. Therefore, the inclined nozzle allows the gas to more efficiently push the residual slag in the center towards the edge of the ladle, enhancing the stability of the slag-free area. The immersion depth of 50 mm to 150 mm avoids both shallow immersion (causing the gas to directly escape from the liquid surface and insufficient slag-driving power) and excessive immersion (causing excessive gas diffusion and inability to concentrate its effect on the slag layer). The refractory material can withstand the erosion of high-temperature molten steel and sudden temperature changes, extending the service life of the air gun 30 and reducing the frequency of replacement.

[0013] Secondly, embodiments of this application provide an RH vacuum refining method, employing the RH vacuum refining apparatus described in any of the above claims, comprising the following steps: S1. Start the permeable bricks and gas pipelines of the RH vacuum refining device to blow gas into the molten steel, blow away the slag in the middle of the ladle, and form an initial slag-free area; S2. Start the drive mechanism, rotate the air gun above the ladle and immerse the gun head in the molten steel, blow gas into the molten steel, and drive the residual slag to the edge of the ladle; S3. Activate the detection mechanism to perform real-time detection on the central area of ​​the ladle; S4. When the detection mechanism detects that the target area meets the slag-free condition, it sends a trigger signal to the control mechanism. The control mechanism controls the ladle to rise and simultaneously controls the drive mechanism to drive the air gun to rotate out of the area above the ladle. S5. Adjust the height of the ladle to the process requirements and perform vacuum refining; S6. After refining is completed, control the ladle to descend.

[0014] Therefore, the two-step slag removal method of bottom blowing and air gun works together to create a larger slag-free area, less residue, and stronger stability than a single slag removal method. The detection trigger and linkage control replace manual observation and operation, eliminating the response delay of manual operation. It can complete the immersion action of the impregnation tube at the best time of slag-free state, avoiding the slag from spreading back to the middle due to untimely operation. The air gun and ladle lifting move synchronously, which not only avoids interference between the air gun and the impregnation tube, but also shortens the waiting time between processes and improves the overall refining efficiency.

[0015] In one possible implementation, in step S1, the gas flow rate is 200 L / min to 1000 L / min, and the blowing time is 2 min to 4 min; and / or, in step S2, the gas flow rate is 100 L / min to 1000 L / min, and the blowing time is 1 min to 3 min. Thus, the bottom blowing flow rate range of 200 L / min to 1000 L / min matches the volume of a conventional ladle, ensuring the formation of a sufficiently large slag-free zone: too low a flow rate results in insufficient airflow power, failing to effectively blow away the slag layer; too high a flow rate easily causes molten steel splashing, posing a safety hazard. The air gun flow rate of 100 L / min to 1000 L / min matches the gun head immersion depth, providing sufficient thrust to move the slag to the edge without excessively agitating the molten steel, causing the slag to be re-rolled back to the center. The corresponding blowing time ensures the slag removal process is fully completed while controlling the overall process time, balancing refining effect and production rhythm.

[0016] In one possible implementation, in step S3, when the detection mechanism detects that the slag thickness in the target area is less than 0.5 mm, it is determined that the slag-free condition is met. Thus, using a quantified slag thickness value as the judgment standard replaces the qualitative judgment based on manual visual observation, eliminating judgment biases caused by differences in operator experience and visual fatigue. The judgment standard is unified for each furnace run, resulting in higher consistency of results. The 0.5 mm threshold setting ensures that there is essentially no slag residue in the central area, meeting the process requirements of slag-free refining and avoiding slag entrapment, while also avoiding excessively high threshold settings that lead to excessively long detection waiting times, thus balancing refining quality and production efficiency.

[0017] In one possible implementation, in step S4, the control mechanism drives the ladle to rise via the lifting mechanism of the RH vacuum refining device until the lower end of the immersion tube of the RH vacuum refining device is immersed in the molten steel to a depth of 5 cm, at which point the rise stops. This initial immersion depth of 5 cm ensures that the lower end of the immersion tube is completely submerged in the molten steel, forming a sealed vacuum circulation channel and preventing air from being drawn in during the vacuuming process, thus affecting the vacuum level. Simultaneously, this shallow immersion depth avoids disturbing the slag accumulated at the edge of the ladle, maintaining the stability of the slag-free central area and preventing slag from being drawn into the circulating molten steel, causing secondary pollution. Closed-loop control via a displacement sensor allows for precise control of the lifting stop position, avoiding height errors from manual operation, ensuring consistency of process parameters for each heat, and improving the stability of the refining process. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of an RH vacuum refining apparatus provided in an embodiment of this application; Figure 2 This is a top view of a steel ladle provided in an embodiment of this application.

[0020] Figure label: RH vacuum refining unit-1; ladle-10; molten steel-101; drive mechanism-20; rotating mechanism-210; lifting mechanism-220; air gun-30; detection mechanism-40; permeable brick-; vacuum chamber-60; impregnation tube-70. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that all directional indications in the embodiments of this invention are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. In this invention, unless otherwise explicitly specified and limited, the terms "connection" and "fixed" should be interpreted broadly. For example, "fixed" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction relationship between two components, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances. In addition, the descriptions involving "first," "second," etc., in this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] In related technologies, the RH vacuum refining process largely relies on manual visual identification of the slag surface state and manual control of ladle lifting and auxiliary equipment movements. This results in large errors in slag-free zone determination, high operational response delays, and the potential for damaging the established slag-free zone, leading to inconvenience in use. This application provides an RH vacuum refining device and method that uses a bottom-blowing device and air gun to collaboratively construct a stable slag-free zone. Combined with a detection mechanism to monitor the slag surface state in real time, and a control mechanism to coordinate ladle lifting and air gun avoidance actions, this approach can at least partially solve the technical problems of low accuracy in slag-free refining determination and poor equipment operational coordination, which cause inconvenience in use.

[0024] This application is described below with reference to the accompanying drawings and specific embodiments: Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the structure of an RH vacuum refining apparatus provided in an embodiment of this application. Figure 2 This is a top view of a steel ladle provided in an embodiment of this application.

[0025] This application provides an RH vacuum refining apparatus 1, which includes a ladle 10, a drive mechanism 20, an air gun 30, a detection mechanism 40, and a control mechanism.

[0026] A ladle 10 is used to hold molten steel 101. A drive mechanism 20 is located above the ladle 10. An air gun 30 is connected to the drive mechanism 20, which drives the air gun 30 to extend into the molten steel 101. A detection mechanism 40 is located above the ladle 10. A control mechanism is electrically connected to both the detection mechanism 40 and the drive mechanism 20.

[0027] In one possible embodiment, the ladle 10 is a high-temperature resistant steel container used to hold the molten steel 101 to be refined, and its bottom center has a flat structure.

[0028] In one possible embodiment, a frame is mounted above the ladle 10, a drive mechanism 20 is fixedly mounted on the frame, and an air gun 30 is connected to the output end of the drive mechanism 20 and can be driven by the drive mechanism 20 to extend into the molten steel 101 inside the ladle 10.

[0029] In one possible embodiment, a height-adjustable support is installed above the ladle 10. The height-adjustable support is made of stainless steel and its vertical distance from the ladle 10 can be adjusted according to the testing requirements. The testing area precisely corresponds to the slag-free target area in the middle of the ladle 10.

[0030] In one possible embodiment, the detection mechanism 40 uses infrared detection with a detection accuracy of <0.1 mm and a response time of <0.5 s, and is used to detect the slag thickness in the target area in real time and provide feedback signals.

[0031] In one possible embodiment, the control mechanism includes a PLC controller, a signal receiver, and an actuator, which are electrically connected to the detection mechanism 40, the drive mechanism 20, and the lifting mechanism (not shown in the figure) that raises and lowers the ladle 10 via wired signals. The controller is used to receive the slag-free trigger signal from the detection mechanism 40 and control the drive mechanism 20 and the lifting mechanism to complete automated actions according to a preset threshold.

[0032] In one possible embodiment, there are multiple drive mechanisms 20 and air guns 30, and they correspond one-to-one. For example, two sets of drive mechanisms 20 and air guns 30 are arranged symmetrically along the outer periphery of the ladle 10.

[0033] In one possible embodiment, an RH vacuum refining apparatus includes a vacuum chamber 60 and an immersion tube 70. The immersion tube 70 is fixed to the bottom of the vacuum chamber 60, with its lower end pointing vertically downwards, precisely corresponding to the slag-free target area in the middle of the ladle 10. It is used to immerse the molten steel 101 to form a sealed vacuum refining environment, thereby realizing the vacuum refining treatment of the molten steel 101.

[0034] The detection mechanism 40 collects the status signal of the slag surface in the middle of the ladle 10 in real time and transmits it to the control mechanism. The control mechanism has built-in judgment logic. After judging the signal, it outputs an action command to the drive mechanism 20. The drive mechanism 20 drives the air gun 30 to complete the station switching and immersion action, forming a closed-loop control link of detection-judgment-execution.

[0035] Therefore, the detection mechanism 40 can acquire the slag surface status in real time, replacing manual visual observation and eliminating the errors and delays of human observation. The control mechanism directly controls the drive mechanism 20 based on the detection signal, eliminating the need for manual intervention and resulting in a faster response speed. It can complete the switching of the air gun 10 at the optimal time when the slag-free area is formed, avoiding slag re-diffusion caused by operational delays. The air gun 10 can actively extend into the molten steel 101 to act on the slag layer. Compared with relying solely on the natural flow of molten steel to drive away slag, the effect of driving away residual slag is more direct and more stable.

[0036] Please see Figure 1 and Figure 2 In this embodiment of the application, the driving mechanism 20 includes a rotating mechanism 210 and a lifting mechanism 220. The rotating mechanism 210 is used to drive the air gun 30 to rotate horizontally into or out of the ladle 10, and the lifting mechanism 220 is used to drive the air gun 30 to rise and fall vertically.

[0037] In one possible embodiment, the horizontal rotation angle range of the rotating mechanism 210 is 0° to 180°.

[0038] In one possible embodiment, the rotating mechanism 210 uses a servo rotary motor, and the lifting mechanism 220 uses a linear lifting cylinder. For example, when the servo rotary motor rotates, it drives the air gun 30 to rotate horizontally around the output shaft, realizing the switching between the working position above the ladle 10 and the outer clearance position of the air gun 30; when the lifting cylinder is ventilated, the piston rod drives the air gun 30 to move up and down in the vertical direction, precisely adjusting the depth of the gun head immersed in the molten steel 101.

[0039] Thus, the rotating mechanism 30 can realize the switching of the air gun's position. During the slag removal operation, it is rotated into the ladle 10 and rotated out to the outside when entering the vacuum refining process, so as to avoid structural interference between the air gun 10 and the descending immersion tube and ensure smooth process connection. The lifting mechanism independently controls the immersion depth and can flexibly adjust the purging position according to the slag layer thickness and the liquid level of molten steel 101, so that the air gun airflow always acts on the optimal slag removal depth and ensures the slag removal effect.

[0040] Please see Figure 1 and Figure 2 In this embodiment of the application, the RH vacuum refining apparatus 1 includes a permeable brick 50 and a gas pipeline. The permeable brick 50 is embedded in the bottom of the ladle 10, and the gas pipeline is connected to the permeable brick 50.

[0041] Schematic illustration: A mounting groove matching the shape of the permeable brick 50 is formed at the center of the bottom of the ladle 10, and the permeable brick 50 is embedded in the groove; a gas pipeline enters from the outside of the bottom of the ladle 10, one end of which is sealed to the air inlet of the permeable brick 50, and the other end extends to the outside of the ladle 10 to connect to an external gas supply source. The gas output from the external gas source is transported to the interior of the permeable brick 50 through the gas pipeline, diffuses evenly through the diffused micropores inside the permeable brick 50, and smoothly enters the molten steel 101 from the top surface, forming a continuous upward airflow from bottom to top.

[0042] In one possible embodiment, the top surface of the permeable brick 50 is flush with the inner bottom surface of the ladle 10, so that it will not form a protrusion to hinder the flow of molten steel, nor will it easily accumulate slag to block the air holes, thus maintaining a stable blowing effect for a long time.

[0043] As a result, the gas is blown upward from the bottom center of the ladle 10, and the rising airflow drives the molten steel 101 in the middle to flow upward, thereby pushing the slag covering the surface to spread around the ladle 10, forming a slag-free area in the middle of the ladle 10.

[0044] Please see Figure 1 and Figure 2 In this embodiment of the application, there are multiple breathable bricks 50, and the multiple breathable bricks 50 are concentric.

[0045] For example, three permeable bricks 50 are evenly arranged around the center of the bottom of the ladle 10, forming an equilateral triangle. Each permeable brick 50 is connected to an independent branch gas pipeline, and all branch gas pipelines converge into a main gas pipeline. A total flow regulating valve is installed on the main pipeline. The independent branch pipelines ensure uniform gas supply pressure to each permeable brick, preventing insufficient gas volume in a single permeable brick and improving the stability of the overall bottom blowing effect.

[0046] The gas transported by the main gas pipeline is evenly distributed to each permeable brick 50 through branch pipelines. Multiple permeable bricks 50 release gas simultaneously, forming multiple upward airflows in the central area at the bottom of the ladle 10. These multiple airflows overlap and cover a larger central area.

[0047] Therefore, after multiple permeable bricks 50 are evenly arranged along the center, the airflow superimposes to form an upward flow field with a larger range and more even distribution, which can blow away the slag in the middle more quickly, and the boundary of the slag-free area formed is more regular, reducing local slag residue. Please see Figure 1 and Figure 2 In this embodiment, the gas in the air gun 10 and the gas pipeline is argon or carbon dioxide.

[0048] Argon is an inert gas that does not react chemically with the elements in molten steel. When blown in, it only serves to stir and remove slag, without contaminating the steel composition. It is suitable for the refining requirements of most high-quality steels. Carbon dioxide can play an auxiliary role in decarburization during the refining process of some steel grades.

[0049] Therefore, the availability of two gas sources allows the device to adapt to the process requirements of more steel grades, thus broadening its applicability.

[0050] Please see Figure 1 and Figure 2 In this embodiment, the nozzle of the air gun 30 is made of refractory material and is inclined toward the edge of the ladle 10 at an angle of 30° to 60°. The nozzle can be immersed 50 mm to 150 mm below the surface of the molten steel 101.

[0051] For example, the nozzle of the air gun 30 is made of Al2O3-SiC refractory material, and the outlet end of the nozzle is inclined towards the side wall of the ladle at an angle of 45°. In operation, the drive mechanism 20 lowers the air gun 30, immersing the outlet end of the nozzle 100 mm below the surface of the molten steel 101. The inclined outlet end causes the ejected gas to rush obliquely towards the edge of the ladle 10, and the depth of immersion below the liquid surface ensures that the gas directly acts on the molten steel 101 below the slag layer. The flow of the molten steel 101 drives the surface slag layer to move towards the edge.

[0052] Therefore, the nozzle is tilted towards the edge, which allows the gas to more efficiently push the residual slag in the middle towards the edge of the ladle 10, enhancing the stability of the slag-free area. The immersion depth is set in the range of mm to 1 mm, which avoids both shallow immersion causing the gas to rush directly out of the liquid surface and insufficient slag-driving power, and deep immersion causing excessive gas diffusion and inability to concentrate the effect on the slag layer. The refractory material can withstand the erosion of high-temperature molten steel 101 and sudden temperature changes, extending the service life of the air gun 30 and reducing the frequency of replacement.

[0053] Based on the same inventive concept, this application also provides an RH vacuum refining method, employing any of the RH vacuum refining apparatuses described in the above embodiments, comprising the following steps: S1. Start the permeable brick 50 and gas pipeline of RH vacuum refining unit 1 to blow gas into molten steel 101, blow away the slag in the middle of ladle 10, and form an initial slag-free area. S2. Start the drive mechanism 20, screw the air gun 30 into the ladle 10 and immerse the gun head into the molten steel 101, blow gas into the molten steel 101, and drive the residual slag to the edge of the ladle 10. S3. Start the detection mechanism 40 to conduct real-time detection on the central area of ​​the ladle 10; S4. When the detection mechanism 40 detects that the target area meets the slag-free condition, it sends a trigger signal to the control mechanism. The control mechanism controls the ladle 10 to rise, and at the same time controls the drive mechanism 20 to drive the air gun 30 to rotate out of the area above the ladle 10. S5. Adjust the height of ladle 10 to the process requirements and perform vacuum refining; S6. After refining is completed, control the ladle to descend.

[0054] The permeable brick 50 and the air gun 30 work together in two steps to remove slag, first forming a large slag-free zone, and then removing the residual slag in a more refined manner. The detection mechanism 40 acts as a trigger node, converting the physical state of the slag surface into an electrical signal input to the control mechanism. The control mechanism outputs two control signals simultaneously to achieve the linkage action of lifting the ladle 10 and avoiding the air gun 30, ensuring the synchronous connection of the processes.

[0055] Therefore, the two-step slag removal method of bottom blowing and air gun works together to form a larger slag-free area, less residue, and stronger stability than a single slag removal method. The detection trigger and linkage control replaces manual observation and operation, eliminating the response delay of manual operation. It can complete the immersion action of the impregnation tube at the best time of slag-free state, and avoid the slag from spreading back to the middle due to untimely operation. The air gun 30 and the ladle 10 lift synchronously, which not only avoids interference between the air gun 30 and the impregnation tube 70, but also shortens the waiting time of process connection and improves the overall refining efficiency.

[0056] In this embodiment of the application, in step S1, the gas flow rate is 200 L / min to 1000 L / min, and the blowing time is 2 min to 4 min; and / or, in step S2, the gas flow rate is 100 L / min to 1000 L / min, and the blowing time is 1 min to 3 min.

[0057] The bottom blowing stage uses a relatively large air volume and a long duration to provide sufficient stirring power and blow away the entire slag layer to form a basic slag-free zone. The air gun stage 30 uses an appropriate air volume and duration to specifically blow away the thin slag layer remaining at the edge. Too much air volume will cause violent fluctuations on the slag surface, and too long a duration will increase unnecessary process time.

[0058] Therefore, a bottom blowing flow rate range of 200 L / min to 1000 L / min, matched with the volume of a conventional ladle, ensures the formation of a sufficiently large slag-free zone: too low a flow rate results in insufficient airflow power, failing to effectively blow away the slag layer; too high a flow rate easily causes molten steel splashing, posing a safety hazard. An air gun flow rate of 100 L / min to 1000 L / min is matched with the gun head immersion depth, providing sufficient thrust to move the slag to the edge without excessively agitating the molten steel, preventing the slag from being re-rolled back into the center. The corresponding blowing duration ensures the slag removal process is fully completed while controlling the overall process time, balancing refining effect and production rhythm.

[0059] In this embodiment of the application, when the detection agency 40 detects that the slag thickness in the target area is less than 0.5 mm, it is determined that the slag-free condition is met.

[0060] Therefore, using quantified slag thickness as the judgment standard replaces qualitative judgment by manual visual observation, eliminating judgment bias caused by factors such as differences in operator experience and visual fatigue. The judgment standard is unified for each furnace, resulting in higher consistency of results. The 0.5 mm threshold setting ensures that there is basically no slag residue in the central area, meeting the process requirements of slag-free refining and avoiding slag entrapment, while avoiding excessively high threshold settings that lead to excessively long detection waiting time, thus balancing refining quality and production efficiency.

[0061] In this embodiment of the application, the control mechanism drives the ladle 10 to rise through the lifting mechanism (not shown in the figure) of the RH vacuum refining device 1 until the lower end of the immersion tube 70 of the RH vacuum refining device 1 is immersed in the molten steel 101 to a depth of 5 cm and then stops rising.

[0062] In one possible embodiment, the lifting mechanism that drives the ladle 10 to rise and fall has an integrated displacement sensor. The signal output terminal of the displacement sensor is electrically connected to the control mechanism. After receiving the slag-free trigger signal, the control mechanism starts the lifting mechanism to drive the ladle 10 to rise at a constant speed. The displacement sensor collects the lifting height data of the ladle 10 in real time and feeds it back to the control mechanism. When the calculated depth of the lower end of the immersion tube 70 immersed in the molten steel 101 reaches 5cm, the control mechanism issues a stop command, and the lifting mechanism locks to maintain the current height.

[0063] The displacement sensor collects height data in real time, forming a height closed-loop control with the control mechanism. The control mechanism accurately controls the stop position based on the feedback height value, ensuring that the initial immersion depth of the impregnation tube 70 is consistent in each batch.

[0064] Therefore, an initial immersion depth of 5 cm ensures that the lower end of the immersion tube 70 is completely submerged inside the molten steel 101, forming a sealed vacuum circulation channel and preventing air from being drawn in during the vacuuming process, which would affect the vacuum level. At the same time, this shallow immersion depth will not disturb the slag accumulated at the edge of the ladle 10, thus maintaining the stability of the slag-free area in the middle and preventing slag from being drawn into the circulating molten steel and causing secondary pollution. Through closed-loop control of the displacement sensor, the lifting stop position can be precisely controlled, avoiding height errors caused by manual operation, ensuring the consistency of process parameters for each heat, and improving the stability of the refining process.

[0065] In one possible embodiment, in step S5, In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0066] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0067] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An RH vacuum refining apparatus, characterized in that, include: A ladle, used to hold molten steel; A drive mechanism is disposed above the ladle; An air gun, which is connected to the drive mechanism, the drive mechanism being used to drive the air gun to extend into the molten steel; A testing mechanism is positioned above the ladle; A control mechanism is provided, which is electrically connected to both the detection mechanism and the drive mechanism.

2. The RH vacuum refining apparatus according to claim 1, characterized in that, The driving mechanism includes a rotating mechanism and a lifting mechanism. The rotating mechanism is used to drive the air gun to rotate horizontally into or out of the ladle, and the lifting mechanism is used to drive the air gun to move up and down vertically.

3. The RH vacuum refining apparatus according to claim 1, characterized in that, The RH vacuum refining apparatus includes a permeable brick and a gas pipeline. The permeable brick is embedded in the bottom of the ladle, and the gas pipeline is connected to the permeable brick.

4. The RH vacuum refining apparatus according to claim 3, characterized in that, The number of breathable bricks is multiple, and the multiple breathable bricks are in a circle.

5. The RH vacuum refining apparatus according to claim 3, characterized in that, The gas in the air gun and the gas pipeline is argon or carbon dioxide.

6. The RH vacuum refining apparatus according to any one of claims 1-5, characterized in that, The nozzle of the air gun is made of refractory material and is inclined toward the edge of the ladle at an angle of 30° to 60°. The nozzle can be immersed 50 mm to 150 mm below the surface of the molten steel.

7. A method for RH vacuum refining, characterized in that, The RH vacuum refining apparatus according to any one of claims 1-6 comprises the following steps: S1. Start the permeable bricks and gas pipelines of the RH vacuum refining device to blow gas into the molten steel, blow away the slag in the middle of the ladle, and form an initial slag-free area; S2. Start the drive mechanism, rotate the air gun above the ladle and immerse the gun head in the molten steel, blow gas into the molten steel, and drive the residual slag to the edge of the ladle; S3. Activate the detection mechanism to perform real-time detection on the central area of ​​the ladle; S4. When the detection mechanism detects that the target area meets the slag-free condition, it sends a trigger signal to the control mechanism. The control mechanism controls the ladle to rise and simultaneously controls the drive mechanism to drive the air gun to rotate out of the area above the ladle. S5. Adjust the height of the ladle to the process requirements and perform vacuum refining; S6. After refining is completed, control the ladle to descend.

8. The method according to claim 7, characterized in that, In step S1, the gas flow rate is 200 L / min to 1000 L / min, and the blowing time is 2 min to 4 min; and / or, in step S2, the gas flow rate is 100 L / min to 1000 L / min, and the blowing time is 1 min to 3 min.

9. The method according to claim 7, characterized in that, In step S3, when the detection mechanism detects that the slag thickness in the target area is less than 0.5 mm, it determines that the slag-free condition is met.

10. The method according to claim 7, characterized in that, In step S4, the control mechanism drives the ladle to rise through the lifting mechanism of the RH vacuum refining device until the lower end of the immersion tube of the RH vacuum refining device is immersed in the molten steel to a depth of 5 cm and then stops rising.

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