A spinning reciprocating permanent magnetic stirring device and method

Abstract

The present invention discloses a self-spinning reciprocating permanent magnetic stirring device and method, which includes a sleeve, a permanent magnet, a permanent magnet rotating mechanism, a lifting support, a runway, a trolley, a pallet and a control system. The permanent magnet and the sleeve are nested and assembled, the runway is arranged inside the sleeve through a lifting support, the trolley and the runway are assembled to slide back and forth, the pallet is supported and arranged on the trolley through a pallet rotating mechanism, and the control system is electrically connected to the permanent magnet rotating mechanism, the lifting support, the trolley and the pallet rotating mechanism respectively. The device and method of the present application have a simple structure, are easy to operate, easy to maintain, low cost, and have diversified magnetic field modes, which improve the controllability of the quality of the casting and improve the quality of the casting. It can be widely used in the field of permanent magnetic stirring of metallurgical melts, and can also be used in the field of experimental research, meeting the laboratory's diversified research on the effects of permanent magnetic stirring on melt solidification, structure and performance, etc., laying the foundation for subsequent industrial applications.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical melt stirring, and in particular relates to a self-spinning reciprocating permanent magnetic stirring device and method. Background Art

[0002] Currently, three-phase AC electromagnetic stirrers have become a mainstream, effective, and standard continuous casting configuration that can control the quality of cast strands. Controlling the quality of cast strands by applying electromagnetic stirring to the melt is gaining increasing attention among metallurgists.

[0003] However, electromagnetic stirring requires high-power, variable-frequency current to generate an alternating magnetic field, resulting in complex equipment, high energy consumption, and high maintenance costs. Furthermore, the stirrer must be cooled by flowing water at a certain pressure, but even with high-quality cooling water, the coil lifespan is still relatively short.

[0004] With the rapid development of magnetic materials, permanent magnetic stirring has become an effective alternative to electromagnetic stirring. Studies have shown that the power consumption of permanent magnetic stirring is only one-tenth of that of electromagnetic stirring. Several permanent magnetic stirring devices have emerged in the prior art. For example, Chinese patent CN110152545A discloses a continuous casting permanent magnetic spiral magnetic field stirrer, which uses a spiral magnetic field composed of magnetic steel distributed in a spiral line for magnetic field stirring. The number of magnetic steels used is relatively large, 25-40. Another example is Chinese patent CN208591780U, which discloses a permanent magnetic stirrer that can effectively prevent segregation. The melt is driven to move uniformly by the rotation of propeller-shaped blades. The structure is relatively complex and can only achieve a single magnetic field motion mode. In short, existing permanent magnetic stirring devices have a relatively complex structure and a relatively single magnetic field mode, which is not conducive to regulating and improving the quality of the ingot. In addition, permanent magnetic materials generally face the problem of "demagnetization at high temperature". When the permanent magnetic stirring is operated at high speed, it faces the dilemma of high-temperature cooling, which is also not conducive to the long-term stable operation of the drive mechanism. Furthermore, when common permanent magnetic stirring devices are used in experimental research, they are not conducive to the laboratory's diversified research on the effects of permanent magnetic stirring on melt solidification, structure and properties. Summary of the Invention

[0005] In light of this, the present invention aims to provide a reciprocating permanent magnetic stirring device and method, which boasts a simple structure, easy maintenance, low cost, convenient operation, and a diverse array of magnetic field modes, thereby enhancing the controllability and improving the quality of cast billets. This device is widely applicable to the field of permanent magnetic stirring of metallurgical melts and can also be used in experimental research, satisfying diverse laboratory research needs for studying the effects of permanent magnetic stirring on melt solidification, structure, and properties, laying the foundation for subsequent industrial applications.

[0006] The present invention solves the above problems through the following technical means:

[0007] In the first aspect, the present invention relates to a self-spinning reciprocating permanent magnet stirring device, comprising a sleeve, a permanent magnet, a permanent magnet rotating mechanism, a lifting support, a runway, a trolley, a pallet and a control system, wherein the permanent magnet is nested and assembled with the sleeve, the runway is arranged inside the sleeve through a lifting support, the trolley is reciprocatingly slidingly assembled with the runway, the pallet is supported and arranged on the trolley through a pallet rotating mechanism, and the control system is electrically connected to the permanent magnet rotating mechanism, the lifting support, the trolley and the pallet rotating mechanism respectively.

[0008] Furthermore, the permanent magnet rotating mechanism drives the permanent magnet to rotate forward or reverse, and the permanent magnet rotation speed is 0-200 rpm.

[0009] Furthermore, the permanent magnet includes a pair of arc-shaped NdFeB sintered magnet blocks, the arc angle of the NdFeB sintered magnet blocks is 30°-70°, and the NdFeB sintered magnet blocks are connected to the output end of the permanent magnet rotating mechanism through a connecting piece.

[0010] Furthermore, the walkway is a concave structure, the bottom of which is connected to the lifting support, the top of which is a trolley movement track, and edges are formed around the top to prevent the trolley from running away.

[0011] Furthermore, the round trip cycle of the trolley moving along the road is 30s-180s, and the movement range is -20-+20cm.

[0012] Furthermore, the tray rotating mechanism drives the tray to rotate forward or reverse, and the tray rotation speed is 0-50 rpm.

[0013] Furthermore, a heat insulation layer is provided at the bottom of the tray.

[0014] Furthermore, the control system includes a permanent magnet rotation control module, a lifting support control module, a trolley motion control module and a turntable rotation control module.

[0015] In a second aspect, the present invention relates to a method for stirring a melt using the above-mentioned reciprocating permanent magnetic stirring device, comprising the following steps:

[0016] S1: Adjust the lifting support to the target position;

[0017] S2: Place the crucible containing the melt under investigation on the tray;

[0018] S3: Start the permanent magnetic stirring device and adjust the permanent magnetic stirring parameters, including the permanent magnet direction and speed, the trolley movement cycle and range, and the tray direction and speed.

[0019] Appropriate permanent magnet stirring parameters can be selected based on melt characteristics and research needs. For a specific parameter, different values ​​can be set within a stirring cycle. For example, the permanent magnet can be rotated forward, reverse, and then forward again, and the corresponding speed can also be different. If a lower stirring speed is required, the tray can also be left stationary.

[0020] Beneficial effects of the present invention:

[0021] The device and method of the present application control the rotation speed and direction of the permanent magnet, the movement cycle and range of the trolley, and the rotation speed and direction of the tray through a control system. Under the combined effect, multi-level and diversified control of the magnetic field at the location of the melt is achieved, such as magnetic field intensity, magnetic field movement speed, magnetic field movement mode, magnetic field movement direction, etc., thereby improving the controllability of the quality of the casting.

[0022] In terms of magnetic field strength control, this device controls the magnetic field strength at various locations on the track through a preset support height, and combines the motion control of the trolley on the track to achieve diversified control of the magnetic field strength at the melt during the stirring process.

[0023] In terms of magnetic field movement speed, to address the problem that permanent magnets are prone to generating high temperatures and then losing magnetism under high-speed operation, this device can adopt the method of rotating the permanent magnet and the tray in opposite directions, thereby increasing the relative rotation speed of the permanent magnet and the melt, increasing the upper limit of the stirring speed, and effectively reducing the risk of permanent magnet demagnetization due to high temperature.

[0024] In terms of magnetic field motion pattern control, this device fully utilizes the distribution characteristics of the magnetic field strength between the two magnets (higher on the sides, lower in the center). Through the horizontal reciprocating motion of the trolley carrying the melt, and the rotational motion of the composite permanent magnet and tray, this combined motion creates a dynamic and changing spiral magnetic field at the melt. Compared to existing spiral stirring devices, which utilize the horizontal motion of multiple spirally distributed magnets to generate a moving spiral magnetic field, this device simplifies experimental equipment while making magnetic field control simpler and more diverse, rather than being limited to spiral magnetic fields.

[0025] In terms of stirring effect, the use of direction and position changes is used to continuously adjust the magnetic field motion state of the tray melt, stimulating Lorentz forces of different directions and magnitudes in the melt, thereby causing forced flow of the melt. This not only effectively achieves heat and mass transfer of the melt, achieves melt homogenization, and reduces solute segregation, but also effectively prevents the aggregation and growth of precipitated phases in the melt, resulting in a significant stirring effect. Compared with the traditional single magnetic field movement method, the melt moves in a single direction with the magnetic field, such as horizontal rotation, and relies on turbulence formed by high speed to achieve internal homogenization of the melt. The effect is limited. Moreover, maintaining the same speed and direction for a long time will also cause the precipitated phases in the melt to remain relatively stationary or the relative movement will weaken, weakening the melt stirring effect.

[0026] In terms of application scenarios, this device can be widely used in the field of permanent magnetic stirring of metallurgical melts, and can also be used in the field of experimental research, meeting the laboratory's diversified research on the effects of permanent magnetic stirring on melt solidification, organization and properties, etc. It has significant advantages such as simple structure, easy maintenance, low cost and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below with reference to the accompanying drawings and examples.

[0028] Figure 1 Schematic diagram of the structure of a preferred embodiment of a reciprocating spinning permanent magnetic stirring device of the present invention;

[0029] In the figure: 1--sleeve; 2--permanent magnet; 3--pallet; 4--trolley; 5--walkway; 6--lifting support; 7--permanent magnet rotating mechanism; 8--control system.

[0030] Figure 2 yes Figure 1 Partial magnetic field distribution diagram inside the permanent magnetic stirring device. The magnetic field strength at the center of the permanent magnet is 1400Gs. With the center of the permanent magnet as the origin, the track length is 40cm, and the range of motion of the trolley is (-20, +20); the magnetic field strength changes during the round trip of the trolley as shown in the figure below. Figure 2 As shown, it varies according to the range of motion. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below through the examples. Through these descriptions, the features and advantages of the present invention will become more clear and distinct. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0032] like Figures 1 to 2 As shown, the self-spinning reciprocating permanent magnetic stirring device of this embodiment includes a sleeve 1, a permanent magnet 2, a permanent magnet rotating mechanism 7, a lifting support 6, a runway 5, a trolley 4, a tray 3 and a control system 8. The permanent magnet is nested and assembled with the sleeve, the runway is arranged inside the sleeve through a lifting support, the trolley is assembled with the runway for reciprocating sliding, and the tray is supported and arranged on the trolley through a tray rotating mechanism; before the stirring starts, the height position of the tray can be adjusted by the lifting support to control the initial magnetic field strength at the melt.

[0033] The control system 8 is electrically connected to the permanent magnet rotation mechanism 7, the lift support 6, the trolley 4, and the tray rotation mechanism. This control system 8 includes a permanent magnet rotation control module, a lift support control module, a trolley motion control module, and a turntable rotation control module. It controls the permanent magnet speed and direction, support height, trolley motion cycle, motion range, and tray speed and direction.

[0034] The permanent magnet rotating mechanism 7 drives the permanent magnets to rotate forward or reverse at a speed of 0-200 rpm. The permanent magnets comprise a pair of curved NdFeB sintered magnets, each with an arc angle of 30°-70°. The NdFeB sintered magnets are connected to the output end of the permanent magnet rotating mechanism via a connector. In this embodiment, the arc angle of the NdFeB sintered magnets is 60°.

[0035] The walkway 5 is a concave structure, connected to the lifting support at the bottom, with a trolley track at the top and a trolley anti-escape edge formed around the top. The trolley moves along the walkway with a round trip cycle of 30s-180s and a range of motion of -20-+20cm.

[0036] The bottom of the tray 3 is provided with a heat insulating layer for placing a container containing the melt, such as a crucible; the tray rotating mechanism drives the tray to rotate forward or reverse, and the tray speed is 0-50 rpm.

[0037] During specific operation, the height of the lifting support is pre-adjusted. The rotation of the permanent magnet and tray, as well as the movement of the trolley, is controlled through a control system. The Lorentz force generated by the moving magnetic field drives the melt movement. The speed and direction of the permanent magnet and tray can be controlled to study the effects of magnetic field speed, forward rotation, reverse rotation, or forward rotation followed by reverse rotation on the melt solidification process. The trolley's movement cycle and range can be controlled to adjust the magnetic field strength at the melt's location. Combined with the horizontal rotation of the permanent magnet, the combined movement achieves spiral motion of the magnetic field at the melt, allowing for the study of the effects of magnetic field strength, magnetic field movement pattern, and other factors on the melt solidification process.

[0038] This embodiment further provides a method for stirring a melt using the above-mentioned lifting permanent magnetic stirring device, comprising the following steps:

[0039] S1: Control the adjustable height support to the target position;

[0040] S2: Place the crucible containing the melt under investigation on the tray;

[0041] S3: Start the permanent magnetic stirring device and adjust the permanent magnetic stirring parameters, including the permanent magnet direction and speed, the trolley movement cycle and range, and the tray direction and speed.

[0042] Appropriate permanent magnet stirring parameters can be selected based on melt characteristics and research needs. For a specific parameter, different values ​​can be set within a stirring cycle. For example, the permanent magnet can be rotated forward, reverse, and then forward again, and the corresponding speed can also be different. If a lower stirring speed is required, the tray can also be left stationary.

[0043] To make the above method clearer, the following is further described with specific examples:

[0044] Example 1

[0045] Adjust the height of the lifting support so that the tray is positioned at the center of the permanent magnet, achieving a magnetic field strength of 1400 Gs. Place the MgO crucible containing AH32 shipbuilding steel melt on the tray and activate the permanent magnetic stirring mechanism. Stirring lasts for 30 minutes, with the trolley moving within a range of (-20°, +20°) and a 120-second cycle. The permanent magnet rotates in the forward direction at 180 rpm, while the tray rotates in the reverse direction at 20 rpm. After stirring, remove the ingot and water-cool it to obtain the sample.

[0046] Example 2

[0047] Adjust the height of the lifting support so that the tray is positioned at the center of the permanent magnet and the magnetic field strength is 1400 Gs. Place the MgO crucible containing AH32 shipbuilding steel melt on the tray and activate the permanent magnetic stirring device. Stirring lasts for 30 minutes. During stirring, the trolley moves within a range of (-15, +15) degrees with a 90-second cycle. The permanent magnet rotates in the forward direction at 200 rpm, while the tray rotates in the reverse direction at 20 rpm. After stirring, remove the ingot and water-cool it to obtain the sample.

[0048] To sum up, the device and method of the present application control the speed and direction of the permanent magnet, the movement cycle and range of the trolley, and the direction and speed of the tray through the control system. Under the combined effect, multi-level and diversified control of the magnetic field at the location of the melt is achieved, such as magnetic field intensity, magnetic field movement speed, magnetic field movement mode, magnetic field movement direction, etc., thereby improving the controllability of the quality of the casting.

[0049] In terms of magnetic field intensity control, this device uses a preset support height to control the magnetic field intensity at various locations along the track. Combined with the motion control of the trolley on the track, this allows for diversified control of the magnetic field intensity at the melt during stirring. Regarding magnetic field speed, to address the problem of permanent magnets easily generating high temperatures and subsequently losing magnetism under high-speed operation, this device utilizes a method of rotating the permanent magnets and the tray in opposite directions, thereby increasing the relative rotational speed of the permanent magnets and the melt, raising the upper limit of stirring speed and effectively reducing the risk of permanent magnet demagnetization due to high temperatures. In terms of magnetic field motion pattern control, this device fully utilizes the distribution characteristics of the magnetic field intensity between the two magnets (high on the sides, low in the center). Through the horizontal reciprocating motion of the trolley carrying the melt, combined with the rotational motion of the permanent magnets and tray, the combined motion creates a dynamic, changing spiral magnetic field at the melt. Compared to existing spiral stirring devices, this device utilizes the horizontal motion of multiple spirally distributed magnets to generate a dynamic spiral magnetic field. This simplifies experimental equipment while allowing for simpler and more diverse magnetic field control, rather than being limited to a spiral magnetic field. In terms of stirring effect, the magnetic field motion state of the melt in the tray is continuously adjusted by changing direction and position, stimulating Lorentz forces of different directions and magnitudes in the melt, thereby causing forced flow of the melt. This not only effectively achieves heat and mass transfer of the melt, achieves melt homogenization, and reduces solute segregation, but also effectively prevents the aggregation and growth of precipitated phases in the melt, resulting in a significant stirring effect. Compared with traditional single magnetic field motion methods, the melt moves in a single direction with the magnetic field, such as horizontal rotation, relying on turbulence generated by high speed to achieve internal homogenization of the melt, but the effect is limited. Moreover, maintaining the same speed and direction for a long time will also cause the precipitated phases in the melt to remain relatively stationary or their relative motion will weaken, weakening the melt stirring effect. In terms of application scenarios, this device can be widely used in the field of permanent magnetic stirring of metallurgical melts, and can also be used in the field of experimental research, meeting the diverse laboratory research needs on the effects of permanent magnetic stirring on melt solidification, structure, and properties. It has significant advantages such as simple structure, easy maintenance, low cost, and easy operation.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A reciprocating permanent magnetic stirring device, characterized in that: The invention comprises a sleeve (1), a permanent magnet (2), a permanent magnet rotating mechanism (7), a lifting support (6), a runway (5), a trolley (4), a pallet (3) and a control system (8), wherein the permanent magnet is nested and assembled with the sleeve, the runway is arranged inside the sleeve via the lifting support, the trolley is assembled with the runway in a reciprocating sliding manner, the pallet is supported and arranged on the trolley via the pallet rotating mechanism, and the control system is electrically connected to the permanent magnet rotating mechanism, the lifting support, the trolley and the pallet rotating mechanism respectively; The control system controls the speed and direction of the permanent magnet, the movement cycle and range of the trolley, the direction and speed of the tray, and realizes multi-level and diversified control of the magnetic field at the melt location; The trolley carries the melt in horizontal reciprocating motion, and the composite permanent magnet and the tray rotate, and a moving and changing spiral magnetic field is formed at the melt by utilizing the combined motion.

2. The reciprocating permanent magnetic stirring device according to claim 1, characterized in that: The permanent magnet rotating mechanism (7) drives the permanent magnet to rotate forward or reverse, and the permanent magnet rotation speed is 0-200 rpm.

3. The reciprocating permanent magnetic stirring device according to claim 1, characterized in that: The permanent magnet (2) comprises a pair of arc-shaped NdFeB sintered magnet blocks, the arc angle of the NdFeB sintered magnet blocks is 30°-70°, and the NdFeB sintered magnet blocks are connected to the output end of the permanent magnet rotating mechanism through a connecting piece.

4. The reciprocating spinning permanent magnetic stirring device according to claim 1, characterized in that: The walkway (5) is a concave structure, the bottom of which is connected to the lifting support (6), the top of which is a trolley movement track, and the top is formed with edges around which the trolley can be prevented from running away.

5. The reciprocating spinning permanent magnetic stirring device according to claim 1, characterized in that: The round trip cycle of the trolley (4) moving along the road (5) is 30s-180s, and the range of movement is -20-+20cm.

6. The reciprocating spinning permanent magnetic stirring device according to claim 1, characterized in that: The tray rotating mechanism drives the tray to rotate forward or reverse, and the tray rotation speed is 0-50rpm.

7. The reciprocating spinning permanent magnetic stirring device according to claim 1, characterized in that: The bottom of the tray (3) is provided with a heat insulation layer.

8. The reciprocating spinning permanent magnetic stirring device according to claim 1, characterized in that: The control system (8) comprises a permanent magnet rotation control module, a lifting support control module, a trolley motion control module and a turntable rotation control module.

9. A method for stirring a melt using the self-spinning reciprocating permanent magnetic stirring device according to claim 1, characterized in that: The steps include: S1: Adjust the lifting support to the target position; S2: Place the crucible containing the melt under investigation on the tray; S3: Start the permanent magnetic stirring device and adjust the permanent magnetic stirring parameters, including the permanent magnet direction and speed, the trolley movement cycle and range, and the tray direction and speed.

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