Online refining and degassing process for aluminum alloys

Abstract

This invention relates to an online refining and degassing process for aluminum alloys. It employs an ultrasonic-assisted three-chamber vacuum degasser to refine and degas the molten aluminum alloy in a degassing tank. During refining and degassing, the temperature of the molten aluminum alloy is controlled at 720℃~750℃, the ultrasonic frequency is 20~22kHz, the vacuum degree is 5Pa~1000Pa, and the vacuum holding time is 10~15min. A first inert gas is introduced into the aluminum alloy solution. This invention combines the advantages of ultrasonic degassing, rotary degassing, and vacuum degassing, while significantly optimizing and improving the disadvantages of rotary and ultrasonic degassing. Ultimately, it can significantly improve the degassing effect, shorten the degassing time, reduce bottom slag loss, and significantly reduce the hydrogen content, which can be reduced to below 0.3mL / kg, thereby meeting the production needs of high-quality, high-performance aluminum alloy products.

Description

Technical Field

[0001] This invention relates to an online refining and degassing process for aluminum alloys, belonging to the field of aluminum alloy smelting technology. Background Technology

[0002] In the smelting process of aluminum alloys, refining and degassing are required. Online degassing processes can be broadly categorized into gas blowing and vacuum refining methods.

[0003] The graphite rod / rotor of the fluted degassing machine rotates at very high speeds (>1000 r / min), resulting in a short lifespan and excessive slag formation. Because the bubbles have a short residence time in the molten aluminum, the degassing effect is affected. Operators typically compensate for this by increasing the inert gas flow rate, leading to significant inert gas consumption.

[0004] The vacuum degasser is structurally similar to the flow channel degasser, consisting of two main parts: the degassing channel and the vacuum degassing chamber.

[0005] Vacuum degassing chambers can be classified into single-chamber, double-chamber, and multi-chamber types based on the flow rate of molten aluminum. Unlike box-type and flue-type degassers, the graphite rotor of a vacuum degasser is installed at the bottom of the chamber. The bottom of the chamber has a slot, allowing it to communicate with the degassing tank. When molten aluminum flows through the degassing tank, a negative pressure is created in the chamber by a vacuum pump or other means, raising the molten aluminum level. Once the level reaches a certain height, the graphite rotor begins to rotate and inject inert gas, degassing and refining the aluminum. When degassing is complete, the negative pressure in the vacuum chamber is released, and the molten aluminum level drops until it is level with the level in the degassing tank.

[0006] Vacuum degassing machines offer advantages such as zero residual aluminum and small footprint. Furthermore, because the molten aluminum is degassed and stirred under vacuum, fewer oxides are produced, resulting in a cleaner molten aluminum. However, current vacuum degassing machines have the following disadvantages:

[0007] Because the graphite rotor is installed at the bottom, and there is a lot of slag at the bottom of the molten aluminum, the graphite rotor is prone to wear. Moreover, since the molten aluminum alloy is returned to the degassing tank after degassing, the final hydrogen content can only be reduced to 1.2 mL / kg and cannot be reduced further. For some aluminum alloys that require extremely low hydrogen content, the process needs to be optimized and improved.

[0008] Based on this, the present invention is proposed. Summary of the Invention

[0009] This invention addresses the shortcomings of existing technologies by providing an online refining and degassing process for aluminum alloys. The specific technical solution is as follows:

[0010] The online refining and degassing process for aluminum alloys includes the following steps:

[0011] An ultrasonic-assisted three-chamber vacuum degasser was used to refine and degas the molten aluminum alloy in the degassing tank. During the refining and degassing process, the temperature of the molten aluminum alloy was controlled at 720℃~750℃, the ultrasonic frequency was 20~22kHz, the vacuum degree was 5Pa~1000Pa, the vacuum holding time was 10~15min, and a first inert gas was introduced into the aluminum alloy solution.

[0012] A further improvement is made to the ultrasonic-assisted three-chamber vacuum degassing machine, which includes a vacuum degassing chamber and an ultrasonic generating chamber installed on top of the vacuum degassing chamber. Two metal vibrating plates are installed inside the vacuum degassing chamber, with a gap between the lower end of each metal vibrating plate and the bottom of the vacuum degassing chamber. The vacuum degassing chamber is divided by the two metal vibrating plates into side degassing chambers on both sides and a main degassing chamber located between the two side degassing chambers. The main degassing chamber and the side degassing chambers are connected by a gap between the lower end of the metal vibrating plate and the bottom of the vacuum degassing chamber. The main degassing chamber has a first vent hole connected to a vacuum pump on its top side wall, and the side degassing chamber has a second vent hole connected to a vacuum pump on its top side wall. The bottom side wall of the vacuum degassing chamber has an aluminum alloy molten liquid inlet / outlet hole connected to the degassing tank. The ultrasonic-assisted three-chamber vacuum degassing machine also includes a double-rotating graphite rotor for introducing a first inert gas into the main degassing chamber and the side degassing chamber. The ultrasonic vibration generated in the ultrasonic generating chamber is transmitted to the metal vibrating plate through a liquid medium.

[0013] In a further improvement, the dual-rotating graphite rotor includes a graphite outer cylinder and a hollow jet rod located inside the graphite outer cylinder. The top of the graphite outer cylinder is provided with a hemispherical cap, and the outer wall of the graphite outer cylinder has multiple circular third vent holes. A first conical tube is integrally connected to the lower end of the graphite outer cylinder, and a first circular tube is integrally connected to the lower end of the first conical tube. The first circular tube is embedded in the bottom of the vacuum degassing chamber, and the first circular tube is rotatably connected to the bottom of the vacuum degassing chamber by a first bearing. A first gear is installed at the lower end of the first circular tube, and the first gear is located below the vacuum degassing chamber. The graphite outer cylinder is located inside the vacuum degassing chamber. An opening slit is provided on the side wall of the hollow jet rod along its axial direction, and a conical cap is sealed at the top of the hollow jet rod. The lower end of the rod is integrally connected to a first hollow conical rod segment, the lower end of the first hollow conical rod segment is integrally connected to a first hollow round rod segment, the lower end of the first hollow round rod segment is integrally connected to a second hollow conical rod segment, the lower end of the second hollow conical rod segment is integrally connected to a second hollow round rod segment, and an air inlet pipe is provided at the lower end of the second hollow round rod segment. One end of the air inlet pipe is connected to an inert gas source, and the other end of the air inlet pipe is rotatably connected to the lower end of the second hollow round rod segment. The upper end of the second hollow round rod segment is rotatably connected to the lower end of the first round tube. The first hollow round rod segment is located inside the first round tube, and the first hollow round rod segment and the first round tube are in a clearance fit. A buffer area is provided between the outer wall of the hollow jet rod and the inner wall of the graphite outer cylinder. A second gear is also installed at the lower end of the second hollow round rod segment.

[0014] In a further improvement, the rotation of the graphite outer cylinder is opposite to that of the hollow jet rod.

[0015] In a further improvement, the ultrasonic generating chamber includes an ultrasonic probe mounting chamber, inside which multiple ultrasonic probes are installed in a staggered arrangement.

[0016] In a further improvement, the metal vibrating plate includes a hollow metal plate, the upper end of which is open and the inner cavity of which is connected to the ultrasonic probe mounting chamber; both the ultrasonic probe mounting chamber and the interior of the hollow metal plate are filled with sodium-potassium alloy, and a gap is provided between the liquid level of the sodium-potassium alloy in the ultrasonic probe mounting chamber and the top of the ultrasonic probe mounting chamber; the interior of the ultrasonic probe mounting chamber is also filled with a second inert gas.

[0017] In a further improvement, one side of the hollow metal plate is provided with multiple sets of downwardly recessed arc-shaped protrusions, and the other side of the hollow metal plate is provided with multiple sets of upwardly protruding arc-shaped protrusions. The cross-section of both the first and second arc-shaped protrusions is semi-circular with a diameter of r, and the r values ​​of the first and second arc-shaped protrusions increase sequentially from top to bottom.

[0018] As a further improvement, the top of the ultrasonic generating chamber is equipped with an air valve that connects to the ultrasonic probe mounting chamber.

[0019] In a further improvement, the initial air pressure inside the ultrasonic probe mounting chamber 51 is 0.113 to 0.116 MPa, and the ultrasonic frequency of the ultrasonic probe 52 is 20 kHz.

[0020] Further improvements include a vacuum level of 5 Pa to 50 Pa in the side degassing chamber 13 during refining and degassing, and a pulsed vacuum level in the main degassing chamber 14 within the range of 50 Pa to 1000 Pa. During the vacuuming process, a first inert gas is injected into the vacuum degassing chamber 10 through a dual-rotating graphite rotor 20. The rotational speed of the graphite outer cylinder 21 is 15 to 25 r / min, and the rotational speed of the hollow jet rod 22 is 3600 to 6000 r / min.

[0021] After refining and degassing are completed, the vacuum degassing chamber 10 is restored to normal pressure, and the aluminum alloy solution in the vacuum degassing chamber 10 flows back to the degassing tank.

[0022] The beneficial effects of this invention are:

[0023] The online refining and degassing process for aluminum alloys described in this invention optimizes and improves the existing vacuum degassing process. By combining the advantages of ultrasonic degassing, rotary degassing, and vacuum degassing, and significantly optimizing and improving the disadvantages of rotary degassing and ultrasonic degassing, the degassing effect can be significantly improved, the degassing time can be shortened, the bottom slag removal loss can be reduced, and the hydrogen content can be significantly reduced to below 0.3 mL / kg, thereby meeting the production needs of high-quality and high-performance aluminum alloy products. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the ultrasonic-assisted three-chamber vacuum degassing machine described in this invention;

[0025] Figure 2 This is a schematic diagram of the structure of the dual-rotation graphite rotor described in this invention;

[0026] Figure 3 This is a schematic diagram of the structure of the metal vibrating plate described in this invention;

[0027] Figure 4This is a schematic diagram showing the distribution of the arc-shaped protrusions described in this invention;

[0028] Figure 5 This is a schematic diagram showing the distribution of the arc-shaped protrusion II described in this invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] In the description of this invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] Example 1

[0033] The online refining and degassing process for aluminum alloys includes the following steps:

[0034] An ultrasonic-assisted three-chamber vacuum degasser was used to refine and degas the molten aluminum alloy in the degassing tank. During the refining and degassing process, the temperature of the molten aluminum alloy was controlled at 720℃~750℃, the ultrasonic frequency was 20~22kHz, the vacuum degree was 5Pa~1000Pa, the vacuum holding time was 10~15min, and a first inert gas was introduced into the aluminum alloy solution.

[0035] Example 2

[0036] In Example 1, as Figures 1-2As shown, the ultrasound-assisted three-chamber vacuum degassing machine includes a vacuum degassing chamber 10 and an ultrasound generating chamber 50 installed on top of the vacuum degassing chamber 10. Two metal vibrating plates 30 are disposed inside the vacuum degassing chamber 10, with a gap between the lower end of each metal vibrating plate 30 and the bottom of the vacuum degassing chamber 10. The vacuum degassing chamber 10 is divided by the two metal vibrating plates 30 into side degassing chambers 13 located on both sides and a main degassing chamber 14 located between the two side degassing chambers 13. The main degassing chamber 14 and the side degassing chambers 13 are connected by the gap between the lower end of each metal vibrating plate 30 and the bottom of the vacuum degassing chamber 10. The main degassing chamber 14 is provided with a first vent 16 connected to a vacuum pump on its top side wall, and the side degassing chamber 13 is provided with a second vent 15 connected to a vacuum pump on its top side wall. The vacuum degassing chamber 10 is provided with an aluminum alloy molten liquid inlet / outlet hole 12 connected to the degassing tank on its bottom side wall. The ultrasonic-assisted three-chamber vacuum degassing machine also includes a double-rotating graphite rotor 20 for introducing a first inert gas into the main degassing chamber 14 and the side degassing chamber 13. The ultrasonic vibration generated in the ultrasonic generating chamber 50 is transmitted to the metal vibrating plate 30 through a liquid medium.

[0037] The dual-rotating graphite rotor 20 includes a graphite outer cylinder 21 and a hollow jet rod 22 located inside the graphite outer cylinder 21. A hemispherical cap 24 is provided at the top of the graphite outer cylinder 21, and multiple circular third vent holes 211 are provided on the outer side wall of the graphite outer cylinder 21. A first conical tube portion 25 is integrally connected to the lower end of the graphite outer cylinder 21, and a first circular tube portion 65 is integrally connected to the lower end of the first conical tube portion 25. The first circular tube portion 65 is embedded in the bottom of the vacuum degassing chamber 10. The first circular tube 65 is rotatably connected to the bottom of the vacuum degassing chamber 10 via a first bearing 11. A first gear 61 is mounted on the lower end of the first circular tube 65, and the first gear 61 is located below the vacuum degassing chamber 10. The graphite outer cylinder 21 is located inside the vacuum degassing chamber 10. An opening slit 221 is provided on the side wall of the hollow jet rod 22 along the axial direction of the hollow jet rod 22. A conical cap 222 is sealed on the top of the hollow jet rod 22. The lower end of the jet rod 22 is integrally connected to a first hollow conical rod segment 26, the lower end of the first hollow conical rod segment 26 is integrally connected to a first hollow round rod segment 27, the lower end of the first hollow round rod segment 27 is integrally connected to a second hollow conical rod segment 28, the lower end of the second hollow conical rod segment 28 is integrally connected to a second hollow round rod segment 64, and the lower end of the second hollow round rod segment 64 is provided with an air intake pipe 63. One end of the air intake pipe 63 is connected to an inert gas source, and the other end of the air intake pipe 63... The lower end of the second hollow round rod segment 64 is rotatably connected to the upper end of the second hollow round rod segment 64 and the lower end of the first round tube 65. The first hollow round rod segment 27 is disposed inside the first round tube 65 and the first hollow round rod segment 27 and the first round tube 65 are in clearance fit. A buffer area 23 is provided between the outer side wall of the hollow jet rod 22 and the inner side wall of the graphite outer cylinder 21. The lower end of the second hollow round rod segment 64 is also equipped with a second gear 62.

[0038] First, conventional graphite rotors typically rotate at low speeds, not exceeding 100 r / min. Otherwise, excessive rotation speed would cause excessive disturbance to the liquid surface, resulting in excessive slag formation.

[0039] In this invention, through the dual-rotation structure design, on the one hand, the rotational speed of the graphite outer cylinder 21 can be maintained at a low level, only needing to prevent the aluminum alloy molten metal from accumulating in large quantities at the graphite outer cylinder 21; at low rotational speed, the wear of the graphite outer cylinder 21 is very low; on the other hand, the rotational speed of the hollow jet rod 22 inside can be designed to be very high, and it is preferably made of cast iron. With the design that the rotation of the graphite outer cylinder 21 is opposite to that of the hollow jet rod 22, the gas ejected from the opening slit 221 forms an "air blade". Under high-speed rotation, it continuously and violently shears against the third vent 211. The airflow impact force at the third vent 211 is very large, which helps to improve the dispersion effect of the first inert gas in the aluminum alloy molten metal and saves refining time. Meanwhile, under the same aperture (e.g., 1 mm), the dual-rotation graphite rotor 20 of the present invention is less prone to aluminum inclusions compared to traditional graphite rotors; even when replacing the graphite outer cylinder 21 later, it is convenient to replace without replacing the hollow air jet rod 22.

[0040] A negative pressure is created inside the vacuum degassing chamber 10 by a vacuum pump or other means, thereby raising the liquid level of the molten aluminum alloy inside the chamber. Once the liquid level reaches a certain height, the dual-rotating graphite rotor 20 begins to rotate and inject the first inert gas to degas and refine the molten aluminum alloy. When degassing is complete, the negative pressure inside the vacuum degassing chamber 10 is released, and the liquid level inside the chamber drops until it is level with the liquid level in the degassing tank.

[0041] The dual-rotating graphite rotor 20 is driven to rotate by gears. The side degassing chambers 13 on both sides and the main degassing chamber 14 in the middle are independent of each other, and their corresponding vacuum levels can also be different, thereby meeting different process requirements.

[0042] In this invention, since the rotational speed of the graphite outer cylinder 21 is much lower than that of the existing rotary degassing, it cannot achieve the purpose of rotary degassing; however, since the rotational speed and direction of the hollow jet rod 22 inside it have been optimized by this invention, it can achieve a similar purpose of rotary degassing, thereby improving the degassing effect.

[0043] This invention combines the advantages of ultrasonic degassing, rotary degassing, and vacuum degassing, and significantly optimizes and improves the disadvantages of rotary degassing and ultrasonic degassing, ultimately resulting in a significant improvement in degassing effect.

[0044] Example 3

[0045] In Example 2, as Figures 1-5 As shown, the ultrasonic generating chamber 50 includes an ultrasonic probe mounting chamber 51, inside which multiple ultrasonic probes 52 are installed in a staggered arrangement.

[0046] The metal vibrating plate 30 includes a hollow metal plate 31, the upper end of which is open and the inner cavity of which is connected to the ultrasonic probe mounting chamber 51. Both the ultrasonic probe mounting chamber 51 and the hollow metal plate 31 are filled with sodium-potassium alloy. The sodium-potassium alloy liquid level in the ultrasonic probe mounting chamber 51 is spaced from the top of the ultrasonic probe mounting chamber 51. The ultrasonic probe mounting chamber 51 is also filled with a second inert gas.

[0047] The hollow metal plate 31 has multiple sets of downwardly recessed arc-shaped protrusions 32 on one inner wall and multiple sets of upwardly protruding arc-shaped protrusions 33 on the other inner wall. The cross-sections of the arc-shaped protrusions 32 and 33 are semi-circular with a diameter of r. The r values ​​of the arc-shaped protrusions 32 and 33 increase sequentially from top to bottom.

[0048] The first and second inert gases can be one or more of nitrogen and argon. To facilitate the introduction of the second inert gas, a valve 53 connected to the ultrasonic probe mounting chamber 51 is provided at the top of the ultrasonic generating chamber 50. After the second inert gas is introduced, the initial gas pressure in the ultrasonic probe mounting chamber 51 is 0.113–0.116 MPa. When the ultrasonic probe 52 operates at a frequency of 20 kHz, the cavitation and vibration of the ultrasound will cause the gas pressure in the ultrasonic probe mounting chamber 51 to fluctuate drastically. Through the transmission of the sodium-potassium alloy, the ultrasonic vibration can be rapidly transmitted to the metal vibrating plate 30.

[0049] The second inert gas is mainly used to expel the air inside the ultrasonic probe installation chamber 51, avoiding the influence of oxygen, water vapor, etc. on the sodium-potassium alloy; at the same time, there is a certain air pressure, which can effectively transmit ultrasonic vibrations to the metal vibrating plate 30 during ultrasound.

[0050] The sound field distribution was tested using a hydrophone, and the maximum sound pressure was collected in V (because the hydrophone outputs a voltage value, the voltage value is used to represent the sound pressure). During the test, the vacuum degassing chamber 10 was filled with water, and the temperature was maintained at 30±1℃. In this embodiment, the maximum sound pressure in the ultrasonic probe mounting chamber 51 was 3.55V (the monitoring point was the bottom of the ultrasonic probe mounting chamber 51), the maximum sound pressure in the main degassing chamber 14 was 2.27V (the monitoring point was the middle of the side wall of the main degassing chamber 14), and the sound field attenuation rate was 36.1%. The maximum sound pressure at the bottom of the metal vibrating plate 30 was 3.03V.

[0051] As a control, if the sodium-potassium alloy is replaced with water, and everything else remains the same, the sound field attenuation rate is 70.2%. If neither arc-shaped protrusion 1 (32) nor arc-shaped protrusion 2 (33) is set, and everything else remains the same, the maximum sound pressure level at the bottom of the corresponding metal diaphragm 30 is 2.35V, a decrease of 22.4%, and the sound field attenuation rate is 59.7%. If arc-shaped protrusion 1 (32) is not set but arc-shaped protrusion 2 (33) is set, and everything else remains the same, the maximum sound pressure level at the bottom of the corresponding metal diaphragm 30 is 2.55V, a decrease of 15.8%. If the r-values ​​of arc-shaped protrusion 1 (32) and arc-shaped protrusion 2 (33) are equal, and everything else remains the same, the maximum sound pressure level at the bottom of the corresponding metal diaphragm 30 is 2.73V, a decrease of 9.9%. If both arc-shaped protrusion 1 (32) and arc-shaped protrusion 2 (33) are replaced with long straight strips of the same volume, and everything else remains the same, the maximum sound pressure level at the bottom of the corresponding metal diaphragm 30 is 1.84V, a decrease of 39.3%.

[0052] Example 4

[0053] In Example 3, during refining and degassing, the vacuum level in the side degassing chamber 13 is 5 Pa to 50 Pa, and the vacuum level in the main degassing chamber 14 fluctuates in a pulsed manner within the range of 50 Pa to 1000 Pa. During the vacuuming process, the first inert gas is sprayed into the vacuum degassing chamber 10 through the double-rotating graphite rotor 20. The rotation speed of the graphite outer cylinder 21 is 15 to 25 r / min, and the rotation speed of the hollow jet rod 22 is 3600 to 6000 r / min.

[0054] After refining and degassing are completed, the vacuum degassing chamber 10 is restored to normal pressure, and the aluminum alloy solution in the vacuum degassing chamber 10 flows back to the degassing tank.

[0055] In this embodiment, taking the refining and degassing of 4032 aluminum alloy as an example, the hydrogen content can be reduced to below 0.3 mL / kg (actual specific gravity method); the bottom slag removal loss is 7.3 kg / t. Because the gas pressure in the side degassing chamber 13 is relatively constant with small fluctuations, while the gas pressure in the main degassing chamber 14 located in the middle fluctuates violently and in a pulsed manner, and the liquid level also rises and falls continuously, the slag at the bottom of the aluminum liquid will fluctuate continuously, which is beneficial for subsequent slag removal on the liquid surface, effectively reducing the bottom slag removal loss. As a result, the aluminum alloy melt flowing back into the degassing tank contains less slag, has a more uniform texture, and the hydrogen content will also be reduced to a lower level.

[0056] Refining and degassing are carried out using a conventional vacuum degassing machine with a vacuum level of 5 Pa to 1000 Pa. The vacuum holding time usually needs to be more than 50 minutes, and the hydrogen content can be reduced to as low as 1.2 mL / kg (actual specific gravity method). In addition, due to the large amount of slag at the bottom of the aluminum melt, the slag removal loss at the bottom is usually more than 15 kg / t.

[0057] As a comparison, if the vacuum level in the main degassing chamber 14 is also maintained at 5Pa to 50Pa, the bottom slag removal loss is usually 14.3kg / t.

[0058] In contrast, if the ultrasonic probe 52 is directly inserted into the molten aluminum alloy, the degassing time can be shortened to 8 minutes under the dual action of ultrasonic and vacuum degassing. However, the bottom slag loss is 19.7 kg / t, and the final hydrogen content is as low as 1.16 mL / kg (actual specific gravity method).

[0059] In contrast, if only the dual-rotating graphite rotor 20 is activated without activating the ultrasonic generator chamber 50, the degassing time can be shortened to less than 15 minutes, but the hydrogen content can only be reduced to below 1 mL / kg (actual gravity method). Even if the degassing time is extended further, the hydrogen content will not decrease further. Conversely, if only the ultrasonic generator chamber 50 is activated without activating the dual-rotating graphite rotor 20, the degassing time requires 30 minutes, and the lowest hydrogen content is 1.21 mL / kg (actual gravity method). Even if the degassing time is extended further, the hydrogen content will not decrease further.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An online refining and degassing process for aluminum alloys, characterized in that... Includes the following steps: An ultrasonic-assisted three-chamber vacuum degasser is used to refine and degas the molten aluminum alloy in the degassing tank. During the refining and degassing process, the temperature of the molten aluminum alloy is controlled at 720℃~750℃, the ultrasonic frequency is 20~22kHz, the vacuum degree during the refining and degassing process is 5Pa~1000Pa, the vacuum holding time is 10~15min, and a first inert gas is introduced into the aluminum alloy solution. The ultrasonic-assisted three-chamber vacuum degasser includes a vacuum degassing chamber (10) and an ultrasonic generating chamber (50) installed on the top of the vacuum degassing chamber (10). Two metal vibrating plates (30) are arranged inside the vacuum degassing chamber (10). The lower end of the metal vibrating plate (30) is separated from the bottom of the vacuum degassing chamber (10). The vacuum degassing chamber (10) is divided into two side degassing chambers (13) located on both sides by the two metal vibrating plates (30). The main degassing chamber (14) in the middle of the chamber (13) is connected to the side degassing chamber (13) through the gap between the lower end of the metal vibrating plate (30) and the bottom of the vacuum degassing chamber (10). The top side wall of the main degassing chamber (14) is provided with a first vent (16) connected to the vacuum pump. The top side wall of the side degassing chamber (13) is provided with a second vent (15) connected to the vacuum pump. The bottom side wall of the vacuum degassing chamber (10) is provided with an aluminum alloy molten liquid inlet and outlet hole (12) connected to the degassing tank. The ultrasonic-assisted three-chamber vacuum degassing machine also includes a double-rotating graphite rotor (20) for introducing a first inert gas into the main degassing chamber (14) and the side degassing chamber (13). The ultrasonic vibration generated in the ultrasonic generating chamber (50) is transmitted to the metal vibrating plate (30) through the liquid medium.

2. The online refining and degassing process for aluminum alloys according to claim 1, characterized in that: The dual-rotating graphite rotor (20) includes a graphite outer cylinder (21) and a hollow jet rod (22) located inside the graphite outer cylinder (21). The top of the graphite outer cylinder (21) is provided with a hemispherical cap (24). The outer wall of the graphite outer cylinder (21) is provided with a plurality of circular third vent holes (211). The lower end of the graphite outer cylinder (21) is integrally connected to a first conical tube (25). The lower end of the first conical tube (25) is integrally connected to a first circular tube (65). The first circular tube (65) is embedded in the vacuum degassing chamber (10). At the bottom, the first circular tube (65) is rotatably connected to the bottom of the vacuum degassing chamber (10) by a first bearing (11). A first gear (61) is installed at the lower end of the first circular tube (65), and the first gear (61) is located below the vacuum degassing chamber (10). The graphite outer cylinder (21) is located inside the vacuum degassing chamber (10). The side wall of the hollow jet rod (22) is provided with an opening slit (221) along the axial direction of the hollow jet rod (22). The top of the hollow jet rod (22) is sealed with a conical cap (222). The lower end of the hollow jet rod (22) is integrally connected to a first hollow conical rod segment (26), the lower end of the first hollow conical rod segment (26) is integrally connected to a first hollow round rod segment (27), the lower end of the first hollow round rod segment (27) is integrally connected to a second hollow conical rod segment (28), the lower end of the second hollow conical rod segment (28) is integrally connected to a second hollow round rod segment (64), and an air inlet pipe (63) is provided at the lower end of the second hollow round rod segment (64). One end of the air inlet pipe (63) is connected to an inert gas source, and the other end of the air inlet pipe (63) is connected to an inert gas source. One end is rotatably connected to the lower end of the second hollow round rod segment (64), the upper end of the second hollow round rod segment (64) is rotatably connected to the lower end of the first round tube (65), the first hollow round rod segment (27) is disposed inside the first round tube (65) and the first hollow round rod segment (27) and the first round tube (65) are in clearance fit, a buffer area (23) is provided between the outer wall of the hollow jet rod (22) and the inner wall of the graphite outer cylinder (21); a second gear (62) is also installed at the lower end of the second hollow round rod segment (64).

3. The online refining and degassing process for aluminum alloys according to claim 2, characterized in that: The graphite outer cylinder (21) rotates in the opposite direction to the hollow jet rod (22).

4. The online refining and degassing process for aluminum alloys according to claim 2, characterized in that: The ultrasonic generating chamber (50) includes an ultrasonic probe mounting chamber (51), in which multiple ultrasonic probes (52) are installed in a staggered arrangement.

5. The online refining and degassing process for aluminum alloys according to claim 4, characterized in that: The metal vibrating plate (30) includes a hollow metal plate (31), the upper end of which is open and the inner cavity of which is connected to the ultrasonic probe mounting chamber (51); the interior of the ultrasonic probe mounting chamber (51) and the hollow metal plate (31) are both filled with sodium-potassium alloy, and the sodium-potassium alloy liquid level in the ultrasonic probe mounting chamber (51) is spaced from the top of the ultrasonic probe mounting chamber (51); the interior of the ultrasonic probe mounting chamber (51) is also filled with a second inert gas.

6. The online refining and degassing process for aluminum alloys according to claim 5, characterized in that: The hollow metal plate (31) has multiple sets of downwardly recessed arc-shaped protrusions (32) on one side of its inner wall, and multiple sets of upwardly protruding arc-shaped protrusions (33) on the other side of its inner wall. The cross-sections of the arc-shaped protrusions (32) and the arc-shaped protrusions (33) are both semi-circular with a diameter of r. The r values ​​of the arc-shaped protrusions (32) and the arc-shaped protrusions (33) are arranged to increase sequentially from top to bottom.

7. The online refining and degassing process for aluminum alloys according to claim 5, characterized in that: The top of the ultrasonic generating chamber (50) is equipped with an air valve (53) that communicates with the ultrasonic probe mounting chamber (51).

8. The online refining and degassing process for aluminum alloys according to claim 7, characterized in that: The initial air pressure in the ultrasonic probe installation chamber (51) is 0.113 to 0.116 MPa, and the ultrasonic frequency of the ultrasonic probe (52) is 20 kHz.

9. The online refining and degassing process for aluminum alloys according to claim 8, characterized in that: During refining and degassing, the vacuum degree in the side degassing chamber (13) is 5 Pa to 50 Pa, and the vacuum degree in the main degassing chamber (14) fluctuates in a pulse manner within the range of 50 Pa to 1000 Pa. During the vacuuming process, the first inert gas is sprayed into the vacuum degassing chamber (10) through the double rotating graphite rotor (20). The rotation speed of the graphite outer cylinder (21) is 15 to 25 r / min, and the rotation speed of the hollow jet rod (22) is 3600 to 6000 r / min. After refining and degassing, the vacuum degassing chamber (10) is restored to normal pressure, and the aluminum alloy solution in the vacuum degassing chamber (10) flows back to the degassing tank.

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