Vacuum induction levitation melting and pulling ingot device and method coupled with multi-field assisted solidification

Abstract

A multi-field assisted solidification levitation melting and pulling ingot device includes a melting vessel configured to contain metal so that the metal is heated in the melting vessel, a first electromagnetic generating device configured to surround the melting vessel to heat the metal and levitate the metal within the melting vessel by generating a magnetic field, and an ultrasonic vibration pulling ingot device configured to contact the liquid metal and provide guidance to solid metal solidified from the liquid metal. The ultrasonic vibration pulling ingot device is configured to generate and transmit ultrasonic vibrations to a solidification interface of the metal while guiding the solid metal. A method is also provided.

Description

Technical Field

[0001] This invention relates to the field of metal casting, and more specifically to a suspension melting casting apparatus and method. Background Technology

[0002] With the development of science and technology, there is an urgent need for high-quality materials and their processing technologies.

[0003] The cold crucible vacuum induction suspension melting technology achieves non-contact melting of molten metal and crucible walls through the synergistic effect of a segmented water-cooled copper crucible and an electromagnetic field, significantly improving the preparation level of high-purity or reactive metals such as titanium, zirconium, and rare earth elements. Its core advantage lies in utilizing the thermal effect and levitation force generated by the electromagnetic field to keep the melt suspended in a vacuum environment, avoiding crucible material contamination. Simultaneously, electromagnetic stirring improves compositional uniformity, enabling continuous directional ingot pulling and forming of dense bars suitable for subsequent rolling or forging. The melt can be continuously pulled and drawn into shape through an ingot pulling process.

[0004] It is desirable to provide a new metal smelting apparatus / method that can achieve the advantages of uniform composition, refined microstructure, reduced segregation, and excellent mechanical properties. Summary of the Invention

[0005] To address the problems in the prior art, including but not limited to the example problems of the prior art described above, the present invention provides a suspension melting and casting apparatus and method.

[0006] According to one aspect of the present invention, a suspension melting and casting device for coupled multi-field assisted solidification is provided, comprising:

[0007] A melting vessel, configured to contain metal so that the metal can be heated within the melting vessel;

[0008] A first electromagnetic generator is configured to surround a melting vessel, generating a magnetic field to heat the metal to a liquid state and suspend the metal within the melting vessel; and

[0009] An ultrasonic vibration drawing device is configured to contact liquid metal and provide guidance for solid metal solidified from liquid metal.

[0010] The ultrasonic vibration pulling device is configured to generate ultrasonic vibration when guiding solid metal and transmit the ultrasonic vibration to the solidification interface of the metal.

[0011] In one embodiment, the ultrasonic vibration pulling device includes:

[0012] A drawing head, configured to contact the metal and guide its solidification; and

[0013] A transducer is installed in the ultrasonic vibration pulling device to generate ultrasonic vibration;

[0014] The ultrasonic vibration drawing device is configured to transmit the ultrasonic vibration generated by the transducer to the drawing head.

[0015] In one embodiment, the drawing head includes an end face with an arcuate surface for contacting metal.

[0016] In one embodiment, the ultrasonic vibration drawing device includes an amplitude transformer disposed on the side of the transducer and the drawing head away from the metal, and

[0017] The shape of the amplitude transformer is such that it has an increased cross-sectional area in the vertical direction, so that the area of ​​the end of the amplitude transformer that connects to the transducer is smaller than the area of ​​the end of the amplitude transformer that connects to the spindle head.

[0018] In one embodiment, the ultrasonic vibration pulling device includes:

[0019] An ultrasonic vibration transmission plate, connecting the larger end of the amplitude transformer; and

[0020] Multiple vibration transmission rods are arranged and distributed between the ultrasonic vibration transmission plate and the spindle head, and connect the ultrasonic vibration transmission plate and the spindle head.

[0021] In one embodiment, gaps are maintained between the plurality of vibration transmission bars to provide cooling conduits for the flow of a fluid medium to cool the spindle head.

[0022] In one embodiment, the ultrasonic vibration pulling device includes a pulling device housing, the pulling device housing including a pulling head for pulling the pulling device, and including a traction rod opposite to an end face for contacting metal, configured to be pulled.

[0023] In one embodiment, the suspension melting and drawing device further includes a traction device configured to connect to the traction rod of the ultrasonic vibration drawing device to move the ultrasonic vibration drawing device.

[0024] In one embodiment, the housing of the ultrasonic vibration pulling device is configured to be housed in a melting vessel and to be movable along the melting vessel.

[0025] In one embodiment, the suspension melting and drawing device further includes a second electromagnetic generator arranged around the melting vessel near the region of the solidified metal, and configured to generate a low-frequency alternating magnetic field to agitate the fluid state of the metal.

[0026] Another aspect of the present invention provides a method for suspension melting, comprising:

[0027] Heating the metal to a liquid state and keeping it suspended in a suspending state; and

[0028] An ultrasonic vibration drawing device is used to contact liquid metal and provide guidance for the solid metal solidified from the liquid metal.

[0029] This also includes: when using an ultrasonic vibration pulling device to guide solid metal in contact with liquid metal, generating ultrasonic vibration and transmitting the ultrasonic vibration to the solidification interface of the metal.

[0030] In one embodiment, the method further includes:

[0031] A low-frequency alternating magnetic field is generated in the region of liquid metal near where it solidifies into solid metal, in order to stir the fluid state of the metal. Attached Figure Description

[0032] The accompanying drawings, which are incorporated herein and form a part of this specification, illustrate the invention and, together with the description, further serve to explain the principles of the invention and enable those skilled in the art to make and use the embodiments described herein.

[0033] Figure 1 This is a schematic diagram of the structural layout of an embodiment of the suspension melting and drawing device according to the present invention, including a first electromagnetic generating device and a second electromagnetic generating device;

[0034] Figure 2 This is a schematic diagram of the ultrasonic vibration pulling device according to the present invention;

[0035] Figure 3 yes Figure 2 A schematic cross-sectional view of the ultrasonic vibration drawing device according to the present invention along the DD line is shown;

[0036] Figure 4 This is a schematic diagram of an embodiment of the suspension melting and casting device according to the present invention;

[0037] Figure 5 This is a schematic diagram of the ultrasonic vibration drawing device according to the present invention housed in a melting vessel;

[0038] Figure 6 This is a schematic diagram of the different states of metal according to the present invention and the corresponding partitions of the suspension melting and casting device of the present invention; and

[0039] Figure 7 This is a schematic diagram of the structural layout of an embodiment of the suspension melting and drawing device according to the present invention, which only includes the first electromagnetic generator.

[0040] The features of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein similar reference numerals consistently identify corresponding elements. In the drawings, similar reference numerals generally denote identical, functionally similar, and / or structurally similar elements. Unless otherwise stated, the drawings provided throughout this application should not be construed as being drawn to scale. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0042] However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the invention.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "comprising" as used herein indicates the presence of features, steps, or operations, but does not exclude the presence or addition of one or more other features.

[0044] The terms "first," "second," etc., used herein are for descriptive purposes only, such as distinguishing different components, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features defined with "first" or "second" may explicitly or implicitly include at least one feature. In the description of this application, the term "multiple" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0045] In this application, unless otherwise expressly specified and limited, the use of terms such as "top" or "bottom," "upper," or "lower" to describe the first feature as being above or below the second feature implies that the first and second features are in direct contact or indirect contact through an intermediate medium. The positional relationship between the two features is a relative relationship between top and bottom, and should not be subject to absolute orientation restrictions. It should not be limited to the orientation shown in the figure, but rather the effect of the product or method can be achieved in any orientation. The phrase "higher" than the second feature means that, as shown in the figure, the first feature is at a higher level in the vertical direction relative to the second feature, and does not imply that it must be arranged as shown in the figure during use. The use of terms such as "high," "low," "upper," and "lower" to describe relative positions in this application is not to limit absolute concepts; for example, it is used to describe the relative positions of several features in conjunction with the accompanying drawings.

[0046] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0047] The cold crucible vacuum induction levitation melting and casting technology achieves non-contact between the melt and the crucible wall through electromagnetic levitation, avoiding crucible material contamination and obtaining high-purity materials. However, significant defects still exist in the critical casting and forming stage. For example, uneven distribution of electromagnetic stirring within the molten pool can easily lead to alloy composition segregation, affecting the uniformity of the ingot microstructure and causing alloy composition segregation, coarse columnar grain structure, shrinkage porosity, and frequent bubble defects. Secondly, during directional casting, the transition of the melt from liquid to solid phase lacks effective external physical field intervention, resulting in coarsening of the solute discharge, grain refinement, and equiaxed crystal to columnar grain transformation processes at the casting front, severely affecting subsequent processing performance and reliability. Especially for highly reactive metals such as titanium alloys, even if levitation melting avoids crucible contamination, the coarseness of the as-cast microstructure and the anisotropy of properties remain prominent issues, often requiring complex subsequent hot isostatic pressing or forging processes to improve them. This increases production costs and limits further improvement in material properties. In addition, traditional cold crucible vacuum induction suspension melting and drawing furnaces face significant challenges in dynamic drawing processes: during the drawing of bar stock, the vertical section of the crucible is relatively long, the magnetic field penetration at the bottom of the crucible is insufficient, it is impossible to control the electromagnetic field for the melting and solidification process, the adaptability is insufficient, the impact on melting and solidification behavior is small, and the electromagnetic field parameters are difficult to adapt to complex drawing behaviors.

[0048] This invention provides a novel suspension melting and casting device and method, offering a new technical solution that couples multi-field assisted solidification. Under vacuum induction conditions, the suspension melting and casting device and method enable active and precise online control of the melt casting behavior during the casting process without introducing contamination. This suppresses component segregation, refines the casting structure, and reduces internal defects, thereby directly obtaining metal bars with uniform composition, dense structure, and excellent mechanical properties.

[0049] This invention employs a cold crucible vacuum induction system and a multi-field assisted solidification suspension melting and casting device. It innovatively integrates an ultrasonic-magnetic field composite application device to achieve a synergistic effect on the melt during the metal casting process, or more precisely, in the mushy zone of the casting process. This invention utilizes magnetic field and ultrasonic vibration to assist solidification, resulting in metal rods with finer grains, uniform composition, dense structure, and excellent mechanical properties.

[0050] One embodiment of the present invention provides a suspension melting and casting device. For example... Figure 1As schematically shown, a suspension melting and drawing device may include: a melting vessel 2 configured to contain metal so that the metal is heated within the melting vessel; a first electromagnetic generator 3 configured to surround the melting vessel 2, heat the metal to a liquid state by generating a magnetic field, and suspend the metal within the melting vessel 2; and an ultrasonic vibration drawing device 5 configured to contact the liquid metal and provide guidance for the solidified metal formed by the liquid metal. In this embodiment, the ultrasonic vibration drawing device 5 is configured to generate ultrasonic vibrations during the guidance of the solidified metal and transmit the ultrasonic vibrations to the solidification interface of the metal. In one embodiment, for example... Figure 4 In the embodiment shown, the first electromagnetic generator 3 can be a coil that generates a magnetic field by providing electricity.

[0051] In one implementation of the present invention, the ultrasonic vibration drawing device 5 may include: a drawing head 51 configured to contact the metal and guide the solidified metal; and a transducer 512 disposed in the ultrasonic vibration drawing device 5 to generate ultrasonic vibration. In this embodiment, the ultrasonic vibration drawing device 5 is configured to transmit the ultrasonic vibration generated by the transducer 512 to the drawing head 51.

[0052] In order to describe, Figure 2 An embodiment of an ultrasonic vibration drawing device 5 is shown. Figure 3 In the illustrated implementation, the drawing head 51 includes an end face 59 with an arcuate surface for contacting the metal. The arcuate surface of the end face for drawing is advantageous, as it increases the contact area between the drawing head 51 and the metal, which facilitates heat dissipation of the metal, accelerates the drawing speed, and also increases the stability of the contact and engagement between the end face of the drawing head 51 and the metal.

[0053] In one embodiment, the ultrasonic vibration drawing device 5 may include an amplitude transformer 511 disposed on the side of the transducer 512 and the drawing head 51 away from the metal. The amplitude transformer is shaped to have an increased cross-sectional area in the vertical direction, such that the area of ​​the end of the amplitude transformer 511 connected to the transducer 512 is smaller than the area of ​​the end of the amplitude transformer 511 connected to the drawing head 51. In this embodiment, the transducer 512 converts a high-frequency alternating current signal into mechanical vibration, and the amplitude transformer 511 can receive the vibration of the transducer 512 and amplify the vibration, transmitting it to the drawing head 51. In this embodiment, an amplitude transformer 511 is advantageously provided, which is disposed between the transducer 512 and the drawing head 51. It can not only transmit the vibration of the transducer 512 to the drawing head 51, but also effectively amplify the mechanical vibration provided by the transducer 512, and expand the distribution area of ​​the vibration when transmitted to the drawing head 51. This configuration enables the matching of a larger cross-section drawing head 51 with a smaller transducer 512, and amplifies the mechanical vibration, thereby improving the effect of vibration and achieving cost-effectiveness.

[0054] In one embodiment, the ultrasonic vibration drawing device 5 may further include an ultrasonic vibration transmission plate 55 connected between the amplitude transformer 511 and the drawing head 51, for example, the ultrasonic vibration transmission plate 55 may be welded to the drawing head 51; and a plurality of vibration transmission rods 53 arranged and distributed between the ultrasonic vibration transmission plate 55 and the drawing head 51, and connecting the ultrasonic vibration transmission plate 55 and the drawing head 51. In one embodiment, the plurality of vibration transmission rods 53 may be evenly distributed in the transverse direction, or symmetrically distributed around a center. In one embodiment, the plurality of vibration transmission rods 53 may be a plurality of titanium alloy cylinders, which can better ensure the effective transmission of mechanical vibration; however, other metals or alloys are also possible. In this embodiment, the structure of providing the ultrasonic vibration transmission plate 55 and the plurality of vibration transmission rods 53 between the drawing head 51 and the amplitude transformer 511 is advantageous. Such a configuration can transmit the mechanical vibration transmitted by the amplitude transformer 511 to a part of the drawing head 51 through the plurality of vibration transmission rods 53, thereby achieving good transmission of mechanical vibration and producing a better vibration effect on the drawing head 51. In this invention, the drawing head 51 can be configured with an end face 59 having an arc-shaped surface, which increases the surface area of ​​the end face, thereby achieving a larger distribution area for mechanical vibration. In this invention, the arc-shaped surface of the end face 59 (the side facing the metal) of the drawing head 51 is concave, which allows the arc-shaped end face 59 of the drawing head 51 to generate greater deformation and more complete vibration. The mechanical vibration of the arc-shaped end face 59 of the drawing head 51 is transmitted towards the metal. Each vibration transmission rod 53 can act as a vibration source to generate mechanical vibration on the arc-shaped end face 59. Multiple vibration transmission rods 53 can act as multiple vibration sources to form multiple vibration sources on the arc-shaped surface. These vibrations influence each other, increasing the interactive influence of vibration during the metal drawing process. The growth of the metal from liquid to solid is significantly affected by mechanical vibration. According to this invention, high-intensity ultrasonic vibration acts directly on the solidifying molten metal, breaking dendrites through its cavitation effect, enhancing mass transfer through its acoustic flow effect, and working together with the magnetoacoustic coupling effect to significantly break up primary grains at the solidification front, promote nucleus proliferation, and homogenize solute distribution. The periodic pressure changes generated by ultrasonic vibration propagating in the melt induce cavitation and acoustic flow effects. The cavitation effect manifests as the oscillation, growth, and collapse of microbubbles in the melt. The shock waves and microjets released during collapse act on the primary dendrites at the solidification front, causing fatigue fracture at the dendrite arm roots due to stress concentration, forming numerous fine grain fragments. Simultaneously, the high-pressure pulses generated by cavitation bubble collapse rapidly disperse these fragments throughout the melt, significantly increasing the number of crystal nuclei as heterogeneous nucleation sites. The acoustic flow effect drives macroscopic forced convection in the melt, uniformly transporting the multiplied crystal nuclei throughout the melt region and enhancing solute transport at the solidification interface front, eliminating local enrichment and achieving macroscopic homogenization of solute distribution.The application of ultrasonic vibration in this invention is a novel method for optimizing metal solidification, especially the casting process, using ultrasonic vibration for the first time in the field, and actual results have proven its significant effectiveness.

[0055] In one embodiment of the present invention, the ultrasonic vibration drawing device 5 can generate continuous vibrations with a frequency of 5 to 20 kHz and an amplitude of 5 to 50 μm; however, other frequencies and amplitudes may be used depending on the different metals and drawing conditions.

[0056] In embodiments of the invention, the plurality of vibration transmission rods 53 can be arranged with gaps, which is advantageous. On the one hand, these gaps allow the plurality of vibration transmission rods 53 to complement each other and form multiple vibration sources, resulting in more efficient vibration transmission. On the other hand, these gaps can provide cooling channels for the flow of fluid medium to cool the spindle head 51. Figure 3 The ultrasonic vibration pulling device 5 is shown as follows. Figure 2 At the cross-section of the DD line, the cooling medium 52 (such as water) can flow in from the inlet 510, flow between the multiple vibration transmission rods 53, and flow out from the outlet 54; the cooling medium can carry away the heat of the drawing head 51, cool the drawing head 51, and at the same time cool the multiple vibration transmission rods 53 and the ultrasonic vibration transmission plate 55.

[0057] According to the present invention, the metal is heated to a liquid state in the melting vessel 2. The portion of the metal from its liquid state to the point where it contacts the drawing head 51 and is drawn can be broadly divided into a liquid metal region 81, a paste-like metal region 82, and a solid metal region 83, such as... Figure 6 As shown, these zones can be adjusted as needed to optimize the properties of the drawn metal and the drawing speed. For example, the melting temperature and cooling temperature can be adjusted.

[0058] In this invention, the suspension melting and drawing device may further include a second electromagnetic generator 4, which is separate from the first electromagnetic generator 3. For example, in one embodiment, the first electromagnetic generator 3 is arranged in the melting zone of the melting vessel 2 to heat the metal to a liquid state and keep the metal in a suspended state; the metal is heated to a liquid state within the area of ​​the melting vessel 2 surrounded by the first electromagnetic generator 3. The second electromagnetic generator 4 is arranged in the area of ​​the melting vessel 2 near where the liquid metal solidifies into solid metal (i.e., near the drawing head 51) and is configured to generate a low-frequency alternating magnetic field to suppress turbulence, stir the fluid state (paste-like metal in this invention), and provide a stable environment for ultrasonic vibration. It should be understood that the second electromagnetic generator 4 extends within a certain range, and the area near where the liquid metal solidifies into solid metal should include a region of partially liquid metal, an interface region between the liquid metal and the solid metal, and a region of partially solid metal.

[0059] The smelting container 2 of the present invention can be, for example, a crucible. The smelting container 2 can be placed vertically, and its length extending in the vertical direction can be set as needed. The smelting container 2 can include a region for liquid metal, a region for paste metal, a region for solid metal, and a region for drawing ingots. These regions can all be distributed within the smelting container 2, or at least distributed within the smelting container 2. For example, the region for drawing ingots can be partially located within the smelting container 2. After the metal has completely formed into solid metal, it can gradually leave the smelting container 2, supported by its own rigidity.

[0060] In one embodiment, such as Figure 5 As shown, the ultrasonic vibration drawing device 5 includes a drawing device housing 56, which includes an end for solidifying metal, namely the drawing head 51, and a traction rod 58 opposite to the end for solidifying metal, configured for being drawn. The drawing device housing 56 is configured to accommodate a transducer 512, an amplitude transformer 511, an ultrasonic vibration transmission plate 55, and a plurality of vibration transmission rods 53; it also accommodates cooling pipes. The drawing device housing 56 is adapted to slide along the melting vessel 2 within the melting vessel 2. Under the traction of the traction rod 58 by an external force, the ultrasonic vibration device slides in the melting container 2. When the ultrasonic vibration pulling device 5 is located in the second electromagnetic generator 4, the liquid metal (due to, for example, a decrease in temperature) transforms into a paste-like metal, that is, a portion of the liquid metal begins to solidify into solid metal, or metal seed crystals formed in the liquid metal are about to transform into solid. At this time, the second electromagnetic generator 4 generates a low-frequency alternating magnetic field. The second electromagnetic generator 4 can constrain the flow of the molten metal, suppress turbulence, and stir the melt. At the same time, the ultrasonic vibration pulling device 5 provides mechanical vibration, which acts directly on the melt being pulled. Through its cavitation effect, dendrites are broken, and the acoustic flow effect enhances mass transfer. It also works together with the magnetoacoustic coupling effect that may be generated by the magnetic field to improve the microstructure and properties of the pulled bar. In this embodiment, the pulling head 51 transmits ultrasonic vibration to the solidification interface. At the same time, the specific spatial layout design of the coil of the second electromagnetic generator surrounding the ultrasonic vibration pulling device 5, especially the pulling head 51, is a structural guarantee for realizing the combined field action of ultrasonic vibration and electromagnetic field on the key area. According to the present invention, the second electromagnetic generating device 4 does not heat the metal and does not generate a force to suspend the metal. The second electromagnetic generating device 4 and the first electromagnetic generating device 3 are independent devices and have different functions in the present invention.

[0061] In one embodiment, the suspension melting and drawing device may further include a traction device 7 configured to connect to the traction rod 58 of the ultrasonic vibration drawing device 5 in order to move the ultrasonic vibration drawing device 5. Figure 4A traction device 7 according to an embodiment of the present invention is shown. The traction device 7 may include a lead screw 72, a pulling servo motor 74, and a connecting plate 71. The pulling servo motor drives the lead screw to rotate, thereby driving the connecting plate 71 to move. The connecting plate 71 is connected to the traction device 7 of the suspension melting pulling device, thereby driving the ultrasonic vibration pulling device 5 to move in order to realize pulling. The traction device 7 may also include a lead screw support 73 fixed to the lower furnace body 62, with the lead screw 72 mounted on the lead screw support 73. Figure 4 The suspended melting and drawing device shown pulls the ingot from top to bottom; however, in other embodiments of the invention, the drawing can be performed from bottom to top.

[0062] Figure 2 One implementation of the traction device 7 is shown. Figure 2 In the illustrated embodiment, the ultrasonic vibration pulling device 5 may include a traction rod 58, which may be a hollow rod. The traction rod 58 is provided with an inlet pipe 513 and an outlet pipe 57. An ultrasonic cable 514 for the transducer 512 may also be arranged inside the traction rod 58 so that an external ultrasonic generator can convert the mains power into a high-frequency AC signal and transmit it to the transducer 512.

[0063] exist Figure 4 In the illustrated embodiment, the traction rod 58 of the ultrasonic vibration pulling device 5 can pass through the connecting plate 71 of the traction device 7, and the traction rod 58 can be fixedly connected to the connecting plate 71. Thus, the connecting plate 71 of the traction device 7 can drive the traction rod 58 of the ultrasonic vibration pulling device 5, and thus drive the ultrasonic vibration pulling device 5 to move up and down to realize the pulling of the spindle.

[0064] Figure 4 This is one embodiment of the present invention, in which the structure of a suspension melting and drawing device is shown in detail; however, Figure 4 The structures shown are merely examples to aid in understanding the invention, and the components shown are not essential for other embodiments of the invention. Those skilled in the art can refer to... Figure 4 The illustrated embodiments set up other embodiments of the present invention.

[0065] like Figure 1 and 4 As shown, the suspension melting and pulling device of the present invention may include a first electromagnetic generator 3, a second electromagnetic generator 4, an ultrasonic vibration pulling device 5, and a traction device 7 arranged from top to bottom (melting container 2, such as a crucible).

[0066] In other embodiments, such as Figure 7 As shown, the suspension melting and pulling device may include a first electromagnetic generator 3, an ultrasonic vibration pulling device 5, and a traction device 7 arranged from bottom to top (melting container 2).

[0067] The melting container 2 can be provided, for example, as a segmented main body crucible made of industrial copper, with the copper segments separated by a special insulating material to ensure electromagnetic penetration. In one embodiment, the copper segmented main body crucible has an internal diameter of 60 mm. The melting container 2 (crucible) can also be configured with a water-cooling circuit, such as... Figure 4 As shown, a circulating water pipe 22 is provided at the upper end of the melting vessel 2. The water in the circulating water pipe 22 can be cooled by an external cooling water system (not shown) (for example, connected via an inlet and an opening 21). The suspension melting and drawing device of the present invention can also be connected to an external power supply system, a vacuum system, and an inert gas protection system, etc., which are not specifically shown here.

[0068] The first electromagnetic generating device 3 can be, for example, an electromagnetic coil, such as an electromagnetic coil wound around a melting device, used to confine and heat the metal. In one embodiment, since the metal is heated and held by the first electromagnetic generating device 3, the melting container 2 and the liquid metal can actually be in non-contact or soft contact, and the electromagnetic force can stir the liquid metal, resulting in a uniform melt composition.

[0069] An embodiment of the suspension melting and casting device of the present invention may further include a second electromagnetic generator 4, which is separate from the first electromagnetic generator 3, and the two operate independently, each providing different electromagnetic signals; for example, there is a gap between them. Figure 4 In the illustrated embodiment, an electromagnetic shield 41 is provided between the two devices to shield against interference between the first electromagnetic generator 3 and the second electromagnetic generator 4. The second electromagnetic generator 4 may include an electromagnetic converter 42, an electromagnetic cable 44, and an electromagnetic coil 45, configured to surround the melting vessel 2 and generate the desired electromagnetic field. The second electromagnetic generator 4 may also include water-cooled piping 46 surrounding the melting vessel 2, achieving a cooling effect through cooling water inlet and outlet 43. The second electromagnetic generator 4 can generate a low-frequency alternating magnetic field of 0.5~100Hz, strongly stirring the paste-like metal. Figure 4 As shown, the metal-contacting drawing head 51 is located within the second electromagnetic generator 4. In one implementation, the drawing stroke achieved by the traction device 7 of the suspension melting drawing device is 300 mm, the maximum diameter of the drawing bar 59 is 60 mm, and the drawing speed is adjustable from 0.5 to 30 mm / min. In other implementations, the above parameters may vary depending on the requirements.

[0070] The suspension melting and drawing device of the present invention may also include, for example, a feeding motor 11, a feeding pipe 13, a feeding port 12, and a feeding auger 14, for adding (a certain proportion) metal raw materials into the suspension melting and drawing device. The feeding pipe 13 extends into the upper end of the drawing copper crucible 23, and the upper end of the feeding pipe 13 is provided with a feeding port 12. The auger 14 is provided inside the feeding pipe. The feeding motor 11 is fixed to the upper end of the upper furnace body 61, and the output end of the feeding motor 11 is connected to the auger 14.

[0071] One aspect of the present invention provides a method for suspension melting. In one embodiment, the method includes: heating a metal to a liquid state and keeping the metal suspended, for example using a first electromagnetic generator 3; and contacting the liquid metal with an ultrasonic vibration pulling device 5 and providing guidance for the solidified metal formed by the liquid metal. The method further includes: generating ultrasonic vibrations and transmitting the ultrasonic vibrations to the solidification interface of the metal while contacting the liquid metal with the ultrasonic vibration pulling device 5 to guide the solidified metal, for example using a second electromagnetic generator 4.

[0072] In one embodiment, the method further includes generating a low-frequency alternating magnetic field in a region of the liquid metal near the solid metal to agitate the fluid-state metal.

[0073] The following describes the suspension melting process of the present invention, or the process of using the suspension melting ingot pulling device of the present invention for ingot pulling, with reference to an example.

[0074] First, raw material pretreatment can be carried out. For example, Ni, Ti, Zr, and Cu with a purity greater than 99.9 wt.% can be selected as raw materials. To reduce impurities, the surface of high-purity metal raw materials can be polished and then placed in anhydrous ethanol for ultrasonic cleaning for 15 minutes to remove particulate contaminants.

[0075] The second step is to prepare the ingredients. Weigh the aforementioned raw materials strictly according to their atomic percentages (Ti: 25%, Zr: 25%, Ni: 40%, Cu: 10%). After weighing, classify the raw materials according to their different components, seal them, and remove air to prevent oxidation before smelting.

[0076] Next, prepare for smelting. Clean the furnace thoroughly and place the obtained raw materials into the vacuum induction levitation melting acoustic-magnetic coupling stirring directional solidification ingot pulling device, with the high-melting-point alloy placed in the center of the crucible. Sequentially turn on the three-stage pump and all vacuum valves to evacuate to a vacuum level of 10. -3 Pa, then high-purity argon gas with a purity of 99.99% was introduced, and after gas washing, the vacuum was evacuated again to 7.1×10⁻³ Pa.

[0077] Next comes melting and refining. Turn on the circulating water cooling system, slowly adjust the power to 100kW and maintain it for 1 minute (to preheat the material and dry the moisture in the material), then slowly adjust the power to 223kW until the material is completely melted, and continue refining for 5 minutes. During the refining process, the frequency of the electromagnetic stirring magnetic field is controlled at 5-15kHz.

[0078] Next comes the casting process. After refining, the smelting power supply is turned off, and the magnetic field generator is turned on. The frequency of the electromagnetic stirring magnetic field is controlled at about 50Hz, and the ultrasonic vibration casting device 5 is set at about 20kHz with an amplitude of 20μm. Casting begins at the preset casting speed. After casting is completed, the magnetic field generator and the ultrasonic vibration casting device 5 are turned off, and the resulting alloy ingot is removed.

[0079] The above is an example of metal drawing according to the principles of the present invention. It should be understood that the descriptions of various parameters, temperature, time, composition, etc. in the above example can help to understand the present invention, and other embodiments of the present invention can be conceived based on the disclosure of the present invention.

[0080] This invention incorporates ultrasonic vibration into the metal smelting process and adds a second electromagnetic generator 4 to provide electromagnetic stirring to the metal in the paste-like metal region. This combines the ultrasonic cavitation effect to break dendrites and the acoustic flow effect to homogenize the solute with the flow stabilization of the magnetic field and the electromagnetic stirring effect. The two work synergistically to effectively suppress compositional segregation and the formation of coarse columnar crystals, directly obtaining a cast structure with fine grains, uniform structure, and few defects. This allows many high-performance metal materials (such as titanium, zirconium, rare earth and other highly active / refractory metals) to achieve performance levels close to or better than those achieved by the traditional "smelting + subsequent complex hot working" at the bar stage. The effect is "1+1>2": the magnetic field provides a stable melt environment for ultrasonic cavitation and regulates the flow, while the ultrasound efficiently achieves dendrite breaking and ultra-fine nucleation that the magnetic field cannot accomplish alone. Together, they achieve grain refinement, compositional homogenization and defect suppression, providing an efficient integrated solution for the preparation of high-end homogeneous metal materials.

[0081] It should be understood that in one embodiment of the present invention, ultrasonic vibration alone can effectively break coarse columnar crystals, resulting in finer grains than in the prior art smelting process without ultrasonic vibration, thereby improving the metallic properties of the drawn ingot.

[0082] This concept is specifically achieved by arranging magnet coils around the casting crucible, which can apply static or low-frequency alternating magnetic fields, while simultaneously installing a high-power ultrasonic vibration device at the casting head 51. During casting, the electromagnetic field generated by induction melting mainly performs the functions of melting, suspension, and basic stirring; while the additional steady-state magnetic field is used to constrain melt flow, suppress turbulence, and stir the melt, providing a stable environment for the ultrasonic field; high-intensity ultrasonic waves act directly on the melt being cast, breaking dendrites through cavitation effect, enhancing mass transfer through acoustic flow effect, and working together with the magnetoacoustic coupling effect that may be generated by the magnetic field to significantly break up the primary grains at the casting front, promote crystal nucleus growth, and homogenize the solute distribution. This composite field of ultrasound and magnetic field is not a simple superposition, but rather a coordinated design of phase, power and frequency to act on the mushy region of the ingot pulling process. This allows for active and precise control over the morphology, grain orientation and size of the ingot pulling interface. The ultimate goal is to directly produce uniform, high-performance ingot bars with ultra-fine equiaxed crystals or oriented fine columnar crystals in a single ingot pulling process, meeting the high-quality continuous ingot pulling requirements of high-purity titanium, zirconium, rare earth and other highly active / refractory metals.

[0083] According to the present invention, the frequency / power of ultrasound and the type (steady-state / alternating) / intensity of the magnetic field are combined as a set of matchable and adjustable process parameters to achieve precise adaptation for different materials (such as highly reactive / refractory metals such as titanium, zirconium, and rare earth elements) and different microstructure requirements (fine equiaxed crystals or oriented columnar crystals). This parameter combination design method for achieving specific solidification goals is protected.

[0084] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. It should be noted that implementations not illustrated or described in the drawings or the main text of the specification are forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the components described above are not limited to the various specific structures, shapes, or methods mentioned in the embodiments, and those skilled in the art can easily modify or substitute them.

[0085] Those skilled in the art will understand that the features described in the various embodiments and / or claims of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0086] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A suspension melting and billet pulling device, comprising: A melting vessel, configured to contain metal so that the metal can be heated within the melting vessel; A first electromagnetic generator is configured to surround a melting vessel, generating a magnetic field to heat the metal to a liquid state and suspend the metal within the melting vessel; and An ultrasonic vibration drawing device is configured to contact liquid metal and provide guidance for solid metal solidified from liquid metal. The ultrasonic vibration pulling device is configured to generate ultrasonic vibration when guiding solid metal and transmit the ultrasonic vibration to the solidification interface of the metal.

2. The suspension melting and casting device according to claim 1, wherein the ultrasonic vibration casting device comprises: A puller head, configured to contact the metal and guide its solidification; and A transducer is installed in the ultrasonic vibration drawing device to generate ultrasonic vibration; The ultrasonic vibration drawing device is configured to transmit the ultrasonic vibration generated by the transducer to the drawing head.

3. The suspension melting and billet pulling device according to claim 1 or 2, wherein... The drawing head includes an end face with an arcuate surface for contacting the metal.

4. The suspension melting and billet pulling device according to claim 1 or 2, wherein... The ultrasonic vibration drawing device includes an amplitude transformer, positioned on the side of the transducer and drawing head away from the metal. The shape of the amplitude transformer is such that it has an increased cross-sectional area in the vertical direction, so that the area of ​​the end of the amplitude transformer that connects to the transducer is smaller than the area of ​​the end of the amplitude transformer that connects to the spindle head.

5. The suspension melting and casting device according to claim 2, wherein the ultrasonic vibration casting device comprises: An ultrasonic vibration transmission plate, connecting the larger end of the amplitude transformer; and Multiple vibration transmission rods are arranged and distributed between the ultrasonic vibration transmission plate and the spindle head, and connect the ultrasonic vibration transmission plate and the spindle head.

6. The suspension melting and drawing device according to claim 5, wherein gaps are maintained between the plurality of vibration transmission bars to provide cooling channels for the flow of a fluid medium to cool the drawing head.

7. The suspension melting and billet pulling device according to claim 6, wherein, The ultrasonic vibration pulling device includes a pulling device housing, which includes a pulling head for pulling the ingot and a traction rod opposite to an end face for contacting metal, configured for being pulled.

8. The suspension melting and drawing device according to claim 7 further includes a traction device configured to connect to the traction rod of the ultrasonic vibration drawing device so as to traction the ultrasonic vibration drawing device to move.

9. The suspension melting and drawing device according to claim 7, wherein the drawing device housing of the ultrasonic vibration drawing device is configured to be accommodated in the melting vessel and to be movable along the melting vessel.

10. The suspension melting and drawing device according to claim 1 further includes a second electromagnetic generator arranged in the area near the solidified metal around the melting vessel, and configured to generate a low-frequency alternating magnetic field to stir the fluid metal.

11. A method for suspension melting and casting ingots, comprising: Heating the metal to a liquid state and keeping it suspended in a suspending state; and An ultrasonic vibration drawing device is used to contact liquid metal and provide guidance for the solid metal solidified from the liquid metal. This also includes: when using an ultrasonic vibration pulling device to guide solid metal in contact with liquid metal, generating ultrasonic vibration and transmitting the ultrasonic vibration to the solidification interface of the metal.

12. The method of claim 11, further comprising: A low-frequency alternating magnetic field is generated in the region of liquid metal near where it solidifies into solid metal, in order to stir the fluid state of the metal.

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