CN217844710U - Novel crucible with electromagnetic penetration and magnetic suspension capabilities - Google Patents

Abstract

The utility model discloses a novel crucible with electromagnetic penetration and magnetic suspension capacity, which comprises a crucible wall and a crucible bottom, wherein the inner wall of the crucible is prepared with a coating, and the outer side of the crucible wall surrounds an induction coil; the crucible is made of metal or graphite; the crucible is provided with a cutting seam along the height direction of the crucible, so that the crucible forms a structure formed by combining a plurality of flaps, and the cutting seam between adjacent flaps forms a gap. The crucible of the utility model can improve the melting temperature, shorten the melting time and reduce the energy consumption because the electromagnetic field can penetrate through the crucible wall to directly heat the material; the crucible does not need to be heated to a great degree of superheat, so that the crucible loss can be reduced, and the service life of the crucible is prolonged; because the superheat degree of the crucible is reduced, and because the magnetic levitation force weakens the contact between the molten pool and the crucible wall, the pollution of crucible materials to materials is reduced; the crucible can be used for preparing high-end materials in the ingot pulling-down technology and the directional solidification technology.

Description

Novel crucible with electromagnetic penetration and magnetic suspension capabilities

Technical Field

The utility model relates to a technical field of metal and alloy are smelted, particularly, relate to a novel crucible that has electromagnetism and pierces through and magnetic suspension ability.

Background

The electromagnetic induction melting technology comprises high-frequency induction melting, medium-frequency induction melting, power-frequency induction melting and ultrasonic induction melting technologies, and the melting technologies are mainly used for materials with higher requirements on product quality. Under the condition of higher requirements on product quality, electromagnetic induction melting (induction melting for short) needs to be completed under the protection of vacuum or inert gas.

The crucibles used in induction melting are mostly heat-resistant ceramic crucibles, such as corundum crucibles, magnesia crucibles, zirconia crucibles, etc., but such crucibles cannot be used for melting some high-end materials due to contamination of the materials to be melted or due to the inability to withstand excessively high melting temperatures. Therefore, it is necessary to use a metal crucible or a graphite crucible in some cases. For example, tungsten crucibles, molybdenum crucibles, tantalum crucibles, which melt rare earth metals, rare earth alloys and high melting point compounds, graphite crucibles, which melt refractory metals, copper, aluminum, iridium crucibles, which melt noble metals, semiconductors and produce single crystals, platinum crucibles, etc. When a metal crucible or a graphite crucible is used, in view of the requirements of crucible materials and materials to be melted, melting needs to be performed in an environment protected by vacuum or inert gas, that is, vacuum electromagnetic induction melting technology (vacuum induction melting for short) needs to be adopted.

In the process of using a metal crucible or a graphite crucible to perform induction melting on materials, because the crucible wall has conductivity, eddy currents induced by an electromagnetic field in the crucible are concentrated and distributed along the outer surface of the crucible wall, and the eddy currents have a shielding effect on the electromagnetic field, so that the electromagnetic field cannot enter the crucible to directly heat the materials in the crucible. The melting process can only rely on the electromagnetic field to heat the crucible to high temperature earlier, then, the crucible of high temperature passes through heat conduction with heat transfer to the inside material of crucible, makes the material heat up gradually, just then can realize melting or the reaction of material. Therefore, the technical requirement of induction melting of materials by using a metal crucible or a graphite crucible requires that the crucible has a large superheat degree and needs a long heat conduction time, so that the melting temperature is limited, the service life of the crucible is shortened, and the production efficiency is reduced.

SUMMERY OF THE UTILITY MODEL

The utility model discloses an overcome above-mentioned problem, designed metal crucible or graphite crucible that has electromagnetism penetrability and magnetic suspension effect, the purpose replaces the metal crucible or the graphite crucible of the traditional structure that uses in the past with this kind of crucible in the work is smelted in the response to improve and smelt the temperature, accelerate the smelting process, reduce energy consumption, improve production efficiency, reduce the crucible loss, alleviate the pollution of crucible material to the material. .

The utility model adopts the following technical proposal:

the utility model adopts a novel crucible with electromagnetic penetration and magnetic suspension capacity, which comprises a crucible wall and a crucible bottom, wherein the inner wall of the crucible is prepared with a coating, and the outer side of the crucible wall surrounds an induction coil;

the crucible is made of metal or graphite;

the crucible is provided with a cutting seam along the height direction of the crucible, so that the crucible forms a structure formed by combining a plurality of flaps, and the cutting seam between adjacent flaps forms a gap.

Further, the metal is a metal or an alloy with a melting point higher than that of the smelted material by more than 300 ℃.

Further, the width of the gap varies in the height direction of the crucible.

Furthermore, a groove is processed on the outer wall of the gap of the crucible.

Further, the gap extends from the highest point of the crucible to the lowest point of the crucible;

alternatively, the crucible is left at a certain height for a certain distance without opening the slot.

Further, the slit is a diagonal line, a curved line or a serpentine line extending between the upper and lower end surfaces of the crucible.

Furthermore, the inner wall of the crucible bottom is a conical surface, a hemispherical surface, a spherical table surface or a paraboloid.

Further, a crucible bottom induction ring is arranged below the crucible bottom.

Furthermore, the crucible and the induction coil are both configured into tapered shapes with large upper parts and small lower parts;

or the crucible wall and the induction coil are columnar, and the crucible bottom and the induction coil at the crucible bottom are configured into tapered shapes with large top and small bottom.

Furthermore, a metal or graphite crucible cover is arranged at the upper opening of the crucible, and the crucible cover is slotted to form a structure with flaps.

Compared with the metal or graphite crucible in the prior art, the utility model has the advantages of it is following:

because the electromagnetic field can penetrate through the crucible wall to directly heat materials, the melting temperature can be increased, the melting time is shortened, and the energy consumption is reduced;

because the electromagnetic field directly heats the materials, the crucible does not need to be heated to a large degree of superheat, so that the crucible loss can be reduced, and the service life of the crucible can be prolonged;

because the superheat degree of the crucible is reduced, and because the magnetic suspension force weakens the contact between the molten pool and the crucible wall, the pollution of crucible materials to materials is reduced, and the effect has particularly important significance for the production process with high heating temperature, long smelting time and strict requirements on products;

the crucible can be used for preparing high-end materials in a pull-down ingot technology and a directional solidification technology, and an undivided metal crucible and a graphite crucible cannot be used in the technologies;

by adopting the crucible of the utility model, the non-conductive compound or semiconductor at room temperature can be smelted by the induction power supply.

Drawings

FIG. 1 is a view of a metallic crucible or graphite crucible having a split structure according to the present invention;

FIG. 2 is a schematic view of the vortex and magnetic levitation force formed in the crucible of the present invention;

FIG. 3 is a cross-sectional view of a crucible with grooves machined in the gaps of the crucible petals;

FIG. 4 is a schematic diagram of the magnetic suspension effect of the bottom surface of the molten pool obtained by changing the shape of the inner surface of the crucible bottom;

FIG. 5 is a diagram of the arrangement of the crucible and the induction coil for obtaining an upward directed magnetic levitation force and for obtaining a magnetic levitation force having an upward directed component force;

FIG. 6 is a view showing the arrangement of a crucible and an induction coil in which the crucible wall is cylindrical and the crucible bottom is tapered;

FIG. 7 is a view of a crucible with a crucible cover, a crucible plug and a crucible holder in a melting furnace;

FIG. 8 is a crucible with a tip-over casting function in a melting furnace;

FIG. 9 shows an apparatus for metal distillation using a crucible according to the present invention;

FIG. 10 shows a crucible of the present invention used for pulling down a dummy ingot;

fig. 11 shows an apparatus for melting compounds using the crucible of the present invention.

Wherein, 1-crucible, 2-crucible wall, 3-crucible bottom, 4-induction ring, 5-lamella, 6-gap, 7-molten pool, 8-groove, 9-molten pool bottom, 10-crucible bottom induction ring, 11-crucible cover, 12-crucible frame, 13-insulating heat-insulating material, 14-smelting chamber, 15-crucible plug, 16-mould, 28-spray ring, 29-gas nozzle, 30-metal steam receiver, 31-metal steam, 32-metal crystal, 33-draw bar, 34-ingot blank, 35-temperature field device, 36-ignition material, 37-compound or semiconductor material.

Detailed Description

The following detailed description of the embodiments of the present invention, provided in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

As shown in fig. 1, the present embodiment provides a metal/graphite crucible 1 including a crucible wall 2 and a crucible bottom 3. In the present embodiment, the crucible wall 2 and the crucible bottom 3 may have an integral structure or may have a separate structure. The current output by the induction power supply generates an electromagnetic field through the induction coil 4 surrounding the crucible 1, and a small gap should be kept between the induction coil 4 and the outer wall of the crucible in order to improve the action efficiency of the electromagnetic field. The shape of the cross section (referring tobase:Sub>A section parallel to the axial direction of the crucible, hereinafter, see the same sectionbase:Sub>A-base:Sub>A in fig. 1) of the metal crucible or graphite crucible may be circular, rectangular, square, or other shapes, or may bebase:Sub>A combination of different shapes in the height direction. The crucible bottom 3 can be a plane, a conical surface, a hemispherical surface, a spherical table surface, a paraboloid and other types of curved surfaces, and can also adopt combinations of bottom surfaces with different shapes.

In the present embodiment, the crucible 1 has a slit along the height direction of the crucible, and the crucible 1 is configured by combining a plurality of petals 5, and a gap 6 is provided between adjacent petals 5. Due to the presence of the gap 6, the electromagnetic field can penetrate the crucible 1 into the crucible interior, directly heating the material inside the crucible.

As shown in fig. 2, another effect of the split structure of the crucible 1 is to generate electromagnetic levitation force to the material, specifically: the electromagnetic field B generated by the induction coil 4 forms an induced current I in each crucible flap 5, the eddy currents I in the flaps 5 are combined into an equivalent annular current I1 on the inner wall of the crucible, the material in the induction crucible is induced by the electromagnetic field B entering the crucible 1 to form eddy currents I2, and the material is melted by the heat generated by the eddy currents I2. The material is melted to form a molten pool 7, the eddy I2 is only distributed on the surface of the molten pool 7, and because the direction of the eddy I2 is always opposite to the direction of the equivalent current I1 of the inner wall of the crucible, an electromagnetic action ampere force F exists between the eddy I2 and the equivalent current I1, the force F acts on the surface of the molten pool, the direction of the force F is always vertical to the crucible wall 2 and points to the center of the crucible, and the force is an electromagnetic suspension force. The surface of the molten pool 7 is separated from the inner wall of the crucible 1 by the repulsive force F, and a suspended state is formed. Arrows and F indicate the repulsion force generated between I1 and I2.

In the present embodiment, since the electromagnetic field attenuates when passing through the slit 6 of the crucible flap 5, the wider the slit 6, the better the penetration effect of the electromagnetic field, but the liquid metal leaks due to the excessively large slit 6. The width of the gap 6 can be selected within the range of 0.02 mm-20 mm, and the optimal width of the gap 6 is 0.1 mm-5 mm. Furthermore, the width of the gap 6 can be changed in the height direction of the crucible 1, and a larger gap width can be selected at a position higher than the molten pool 7, so that the resistance of the gap to the electromagnetic field is reduced as much as possible.

In the present embodiment, since the types and the batch sizes of the melting materials related to the crucible 1 are greatly different, the range of covering the size of the crucible 1 is wide. The diameter or the side length of the inner wall of the cross section of the crucible 1 can cover the range of 5mm to 500 mm; the height may be in the range of 5mm to 2000 mm. Increasing the thickness of the crucible wall 2 increases the distance that the electromagnetic field travels through the slot 6, so decreasing the wall thickness increases the efficiency of the electromagnetic field penetration. However, too small a wall thickness reduces the strength of the crucible 1, shortening the life of the crucible. Further, the thickness of the crucible wall 2 of the present embodiment may be selected in the range of 0.1mm to 100 mm. The larger the size of the crucible 1, the greater the thickness of the crucible wall 2. The thickness of the crucible wall 2 is also related to the material of the crucible and the melting point of the material to be melted, the thickness of the precious metal crucible is small, and the thickness of the crucible used for melting the low melting point material is also small. Both the size and the thickness of the crucible cross-section can vary in the height direction of the crucible 1. In order to increase the penetration effect of the electromagnetic field, it is also possible to machine grooves 8 in the outer wall of the crucible at the slot 6, which serve to reduce the actual wall thickness of the crucible at the slot 6, see fig. 3.

In the present embodiment, increasing the number of lobes of the crucible lobes 5 corresponds to increasing the total width of the gaps 6 between the crucible lobes, which is beneficial for increasing the efficiency of the electromagnetic field entering the crucible, but too many lobes reduce the strength of the crucible and increase the manufacturing cost. The number of petals of the crucible petals 5 depends on the inner diameter of the crucible, the number of petals can be selected according to the ratio P of the inner diameter or the side length L of the inner wall of the crucible on the cross section to the side length L of the petals, and specifically, the P value range is 5:1 to 50:1, with 8:1 to 20:1 is the best, the number of the corresponding petals is 4 to 100 petals, and 10 to 50 petals are the best. As another embodiment, the number of petals 5 depends on the size of the crucible cross-section. Specifically, the crucible with the diameter less than 50mm can be designed according to 6-20 petals; the crucible with the diameter larger than 50mm and smaller than 300mm can be designed according to 12-50 petals; the crucible with the diameter larger than 300mm can be designed according to 30-100 petals.

In this embodiment, the gaps 6 of the crucible flaps may be the lowest points of the crucible extending from the highest point of the crucible 1, or may be formed by leaving a distance at a certain height without a slit and leaving a seamless ring, so as to maintain the integral structure of the crucible 1. The seamless ring may be positioned at the uppermost end, the lowermost end, or somewhere in the middle of the crucible. The number of seamless rings may be 1, 2 or more. In some embodiments, the orientation and shape of the slit 6 is a straight line parallel to the crucible axis. In other embodiments, the slot 6 may be a diagonal line, a curved line or a serpentine line extending from between the upper and lower end surfaces of the crucible in order to increase the cumulative total length of the slot 6 and increase the path of the electromagnetic field through the crucible wall 2.

In the present embodiment, since a high electromagnetic field efficiency can be obtained by keeping a small gap between the induction coil 4 and the outer wall of the crucible 1, the shape of the induction coil 4 generating the electromagnetic field is matched with the outer shape of the crucible 1. Since the crucible 1 is generally columnar in shape, the induction coil 4 is generally columnar in shape. Since the direction of the ampere force F generated by the electromagnetic field on the molten pool is perpendicular to the side wall of the induction coil 4, the magnetic levitation force has no upward component in this case, the surface of the molten pool 7 in the crucible forms a gap with the inner wall of the crucible under the action of the force F, but the pressure formed by the gravity of the molten pool 7 on the surface is larger as the distance from the top of the molten pool 7 is larger, so that the molten pool 7 forms a hump shape with a small upper diameter and a gradually larger lower diameter. The levitation effect of the molten pool 7 is gradually reduced in the middle and lower portions, and almost no levitation effect is obtained in the bottom of the molten pool 7. The inner wall of the crucible bottom 3 is designed to be a conical surface, a hemispherical surface, a spherical table surface, a paraboloid or other types of curved surfaces with inclination, and the bottom surface 9 of the molten pool can also be separated from the inner wall of the crucible under the action of F force in the direction vertical to the axis of the crucible, so that a certain suspension effect is obtained, as shown in figure 4.

In the present embodiment, as shown in fig. 5, it is effective to further increase the melting effect by providing the molten pool, particularly the bottom of the molten pool, with an upward magnetic levitation force. In addition to the inductor 4 on the side of the crucible wall 2, the arrangement of the crucible bottom inductor 10 below the crucible bottom 3 makes it possible to generate an additional upwardly directed magnetic levitation force on the bottom of the melt pool 7.

In the present embodiment, as shown in fig. 5, the levitating force F generated by the induction coil 4 and the crucible wall 2 having the taper angle α with the large upper end diameter and the small lower end diameter has not only the inward component Fa but also the upward component Fb. The larger the angle of taper α, the larger the upward component Fb. Therefore, in order to obtain an upward magnetic levitation force, or a magnetic levitation force with an upward component force, the outer shape of the crucible 1 and the arrangement of the induction coil 4 can be configured as follows:

the whole of the crucible 1 and the induction coil 4 are configured in a tapered shape with a large upper part and a small lower part, see fig. 5;

the crucible wall 2 and the induction coil 4 outside the crucible wall are columnar, and the crucible bottom 3 and the induction coil 10 at the crucible bottom below the crucible bottom are tapered, wherein the upper part is large, and the lower part is small, as shown in fig. 6;

it is understood that the crucible bottom induction coil 10 can be an integral part connected with the induction coil 4 on the side surface of the crucible in series, or can be a separate induction coil with a component force mutually with the induction coil 4 on the side surface of the crucible.

In the present embodiment, since the intensity of the ampere force increases as the frequency of the electromagnetic field increases, a relatively large maglev force F can be obtained by increasing the output frequency of the induction power supply. However, increasing the frequency reduces the penetration depth of the electromagnetic field into the material, reducing smelting efficiency. Therefore, when melting is performed using the crucible of the present embodiment, the frequency range of the induction power supply should be in a certain range higher than the frequency used for medium frequency induction melting, and can be selected from the range of 0.5kHz to 1000 kHz. In the case of metal melting, a superaudio induction power supply is preferably used, and the frequency range is limited to a range of 3kHz to 80kHz, preferably 5kHz to 50 kHz. The frequency is determined in relation to the crucible size and should be above 20kHz for crucibles having an internal diameter of less than 50mm and below 8kHz for crucibles having an internal diameter of more than 200 mm.

In order to make the crucible of the utility model have better use effect and perfect function, the following auxiliary measures can be taken for the crucible:

in the present embodiment, a metal or graphite crucible cover 11 may be attached to the upper opening of the crucible 1 in order to keep the temperature of the molten bath constant during the melting process and to increase the melting temperature, as shown in fig. 7. Preferably, the crucible cover 11 is also slit to be made into a structure of combining the petals, and the seamless crucible cover 11 can block the path of the magnetic force lines passing through the upper opening of the crucible 1, so that a part of the electromagnetic field can not enter the crucible.

In the present embodiment, a coating layer may be formed on the inner wall of the crucible in order to prevent contamination of the crucible 1 with the material to be melted. The coating material can be the same metal, alloy and compound as the smelted material, can be a component of the smelted material, and can also be metal, alloy and compound with the melting point higher than that of the smelted material. The preparation method of the coating comprises thermal spraying, plasma spraying, magnetron sputtering and the like.

In the present embodiment, as shown in fig. 7, when a metal crucible or a graphite crucible is installed in a vacuum furnace body, a crucible holder 12 is required, and the crucible holder 12 may be made of a metal material such as carbon steel, stainless steel, or copper, or may be made of a heat-resistant ceramic material. The crucible holder 12 of the metallic material can be provided with a cooling device, and the copper crucible holder must have a water-cooled structure. Between the crucible holder 12 and the crucible bottom 3, a high-temperature resistant insulating material 13 such as asbestos, alumina silicate fiber, alumina, zirconia, magnesia, graphite, or the like is required to be lined.

In the present embodiment, the metal or alloy for forming the metal crucible should be a material having a melting point higher by 300 ℃ or more than that of the material to be melted, and preferably a metal or alloy having a melting point higher by 500 ℃ or more than that of the material to be melted. The material of metal crucibles is widely used in practice, for example, metals such as W, mo, nb, ir and Pt, and alloys thereof, for example, alloys such as W-Mo, W-Re and Ir-Rh.

The method for smelting materials by using the crucible provided by the embodiment comprises the following steps:

in a first aspect:

step 1, after the materials are loaded into the crucible 1, vacuumizing the melting chamber 14, or filling argon after vacuumizing, and then starting an induction power supply to heat the materials.

And 2, increasing the power after the materials are melted and appear in the molten pool, so that the molten pool 7 appears in a suspension state. The suspended state is marked by the degree of humping formed by the molten pool 7, and the diameter of the humping is smaller than 2/3 of the inner diameter of the crucible to meet the requirement. In this state, the outer wall of the molten pool 7 is sufficiently separated from the inner wall of the crucible, and the best melting effect is obtained.

And 3, carrying out casting work after keeping the temperature for a period of time in a suspension state. In some embodiments, the casting process uses a tipping casting technique, where the crucible 1 is tipped by a tipping device and the melt of material is poured into the mold 16 for cooling, see fig. 8. In other embodiments, the casting process may also use a bottom casting technique, which uses a crucible 1 with a bottom casting opening on the crucible bottom 3, and the crucible plug 15 is used to shield the bottom casting opening during the melting process, and when casting is needed, the crucible plug 15 is removed to inject the material melt into a mold 16 below the crucible along the bottom casting opening, as shown in fig. 7. In the above two casting modes, the power of the induction power supply is maintained during casting, so that the molten pool is kept in a suspension state and flows out of the mold 16, and thus the material melt can be almost completely injected into the mold 16, and almost no material remains in the crucible.

In a second aspect:

as shown in fig. 9, the crucible of the present embodiment can be used for a distillation purification technique of metal. The auxiliary equipment and the process used for the distillation purification of the metal are similar to the smelting equipment and the process, but a metal vapor receiver 30 is arranged above the crucible 1 to receive the metal vapor 31 generated by the molten pool 7, so that the metal atoms in the gas state are condensed and crystallized on the metal vapor to form metal crystals 32. It can be understood that the technology has high heating temperature, long process time and very strict requirement on the impurity content, and the technical requirement is difficult to achieve by adopting the existing non-split metal crucible or graphite crucible.

In a third aspect:

as shown in fig. 10, the crucible 1 of the present embodiment can produce a product having excellent quality by the pull-down dummy ingot technique. Specifically, the crucible bottom 3 and the crucible wall 2 have a separation structure, the crucible bottom 3 is used as a crystallizer and is arranged at the lower opening of the crucible wall 2, the lower end surface of the crucible bottom 3 is provided with a pull rod 33 extending downwards, and the pull rod 33 extends to the lower surface of the smelting chamber 14 through vacuum sealing to be combined with an ingot pulling driver. After the materials are melted, an ingot pulling driver is started, the pull rod 33 is pulled down, and the molten pool 7 on the crucible bottom 3 is moved out of the crucible downwards along with the pull rod 33 to be cooled and solidified to form an ingot blank 34. To achieve the desired product quality, the speed of the down-draw process must be very low, typically limited to the range of 0.1mm/min to 100mm/min, and for most materials, the down-draw speed is limited to the range of 1mm/min to 20 mm/min. The advantage of using the pull-down dummy ingot technique is that the solidification process of the liquid material is sequential solidification from bottom to top, so the material of the ingot blank 34 is very compact, and has no metallurgical defects such as shrinkage cavities, pores, looseness, cracks and the like. It will be appreciated that the use of a non-split metal/graphite crucible of the prior art is not possible in the ingot pull-down technique because the temperature of such a crucible is high and the ingot pull-down process takes a long time, typically several hours or more, during which the contamination of the material by the walls of the high temperature crucible is significant and the product of the pull-down ingot is scrapped.

In a fourth aspect:

as shown in fig. 10, the crucible of the present embodiment can also be used for the directional solidification technique. The directional solidification technology is a technology with higher requirements than the pulling-down dummy ingot technology, and requires that a temperature field device 35 is arranged in the pulling-down dummy ingot process, so that a molten pool 7 on the crucible bottom 3 is solidified under the condition of axial temperature gradient when moving out of a crucible lower opening downwards along with a pull rod 33, an ingot blank 34 of directional crystallization is formed, and the purification effect is obtained. It will be appreciated that impurities in the melt pool 7, which serve as nuclei for non-spontaneous nucleation, disrupt the directional crystallisation process and so the cleanliness of the melt pool must be maintained during directional solidification. In addition, the directional solidification process requires a very low pull-down rate, typically an order of magnitude lower than pull-down dummy bar technology. In the face of such stringent impurity requirements and longer metallurgical processes, neither the prior art metal crucibles nor graphite crucibles can be used.

In a fifth aspect:

as shown in fig. 11, using the crucible of the present embodiment, it is possible to melt a compound or semiconductor that is not conductive at room temperature using an induction power source, and melting such a material requires the use of an ignition technique. Specifically, a conductive ignition material 36 is embedded in a non-conductive compound or semiconductor material 37, and an induction power supply is activated to preheat the material to a conductive temperature, so that the high-temperature material is induced to generate heat and melt from the inside under the action of an electromagnetic field, and then the melting range expands to the periphery until the material is completely melted. Preferably, the ignition material 36 is generally metal or graphite. It will be appreciated that with the prior art crucible, the ignition material 36 cannot be used inside the charge because the electromagnetic field cannot enter the interior of the crucible 1. In this case, although the crucible is heated up by the electromagnetic field as an ignition material to heat the material to a conductive temperature, the crucible wall always contaminates the material during the entire melting process of the material and the contamination is very severe because the crucible is at a high temperature.

In the above five aspects, under the condition that the crucible of the present embodiment is employed, a cooled inert gas, or a liquid inert gas such as liquid argon may be blown to the outer wall of the crucible during the melting process. The method for realizing the technology comprises the following steps: referring to FIG. 8, a gas injection ring 28 is provided on the side and/or lower surface of the crucible, and a plurality of gas injection ports 29 are provided in the ring and open upward, and gas lines are joined to the injection ring 28 from the outside of the melting furnace body by vacuum sealing. When the induction power supply is started to heat the material, or after the induction power supply is started to heat the material, a valve for conveying cooled inert gas or liquid inert gas is opened, so that low-temperature gas is sprayed to the crucible through the gas spraying port 29 of the spraying ring 29, and the outer wall of the crucible is cooled. The technology can reduce the temperature of the crucible in the smelting process, reduce the loss of crucible materials and reduce the pollution of the crucible to the materials. It will be appreciated that the above measures for cooling the crucible cannot be taken with the prior art crucibles, since the temperature of the material in the prior art crucibles is provided by the crucible.

The specific embodiment is as follows:

the utility model provides a few concrete embodiments to better understand the utility model discloses.

Detailed description of the preferred embodiment 1

The crucible and the vacuum induction melting equipment in the prior art are composed of an induction power supply with the power of 100kW and the frequency of 2500Hz and a vacuum melting chamber with the inner diameter of 1200mm, a tungsten crucible with the inner diameter of 300mm and the height of 280mm is arranged, and a molybdenum crystallizer is arranged above the crucible. The apparatus was used to distill metal \37841witha 100kg per furnace yield of metal Dy. In the prior art, an electromagnetic field of a medium-frequency power supply firstly heats a tungsten crucible, the tungsten crucible is heated, heat is transferred to dysprosium material, the distillation process is completed by keeping the temperature at 2000 ℃ for 5 hours, and the content of tungsten in the product is more than 1000ppm by distillation method 37841. Under the condition of the production process, the service life of the tungsten crucible is less than 100 heats.

In the case of the technique of the present embodiment, the tungsten crucible is not changed in size by an induction power source having a power of 100kW and a frequency of 5000Hz, but the whole is divided into 36 pieces, and the width of the piece gap is 2mm. A gas injection ring is arranged below the tungsten crucible, 8 gas injection ports which are opened upwards are arranged on the ring, and a liquid argon pipeline is combined on the injection ring through vacuum sealing. And opening a liquid argon valve after starting the induction power supply, so that the low-temperature argon is sprayed to the crucible through the gas spraying port of the spraying ring. In the heating process, the metal dysprosium in the crucible is directly heated, melted and evaporated under the action of an electromagnetic field. By using the new technology, the time for completing the distillation process is shortened to 3 hours, and the tungsten content in the product is less than 300ppm. The new technology not only does not need the tungsten crucible to have high temperature, but also receives the cooling effect, so the service life of the crucible is prolonged to more than 500 heats.

Specific example 2

The crucible in the prior art is adopted, the smelting equipment consists of a high-frequency power supply with the power of 60kW and the frequency of 100kHz and a smelting chamber with the inner diameter of 500mm, and the tantalum crucible with the inner diameter of 60mm is used for smelting high-purity alumina, the smelting amount is 500g, and the temperature is 2200 ℃. The alumina smelted by the method contains 600ppm of impurity Ta, and the quality is not satisfactory.

The utility model discloses a with gap width 0.4mm, the tantalum crucible that falls into 20 lamellas replaces not split crucible to smelt the alumina crucible, buries metallic aluminum ring as ignition material in the crucible. After the induction power supply is started, the aluminum ring is heated and then burns, and the heat generated by the aluminum ring makes the aluminum oxide heated to obtain the electric conduction capability. When heating was continued, the alumina was completely melted. The treated alumina has an impurity content of less than 100ppm.

Specific example 3

The traditional process for preparing the Mo-Re alloy target material is a powder metallurgy technology.

The magnetic suspension smelting technology of the embodiment is used for preparing the Mo-Re alloy casting target material. The device consists of a superaudio power supply with the power of 200kW and the frequency of 12kHz and a vacuum chamber with the inner diameter of 1000mm, wherein the crucible adopts a Mo crucible with the inner diameter of 200mm, and is divided into 30 petals, and the gap between the petals is 1mm. And a Mo coating is manufactured on the inner wall of the crucible by using a plasma spraying technology. 80kg of metal Mo and metal Re are filled into the crucible, the smelting temperature is 2800 ℃, the materials are completely melted after 20 minutes of smelting time, and the materials are cast into a plate-shaped target blank after 3 minutes of heat preservation. The plate blank has high compactness.

Specific example 4

The high purity copper alloy is melted by using a superaudio frequency power supply with the power of 100kW and the frequency of 10kHz and a high purity graphite crucible with the inner diameter of 300mm and divided into 32 petals in a vacuum chamber. The vacuum chamber was evacuated to 3x10 ^-4 Pa, starting an induction power supply to heat the copper alloy raw material, melting, and casting by using a tipping casting technology to obtain the copper alloy rod with the diameter of 60 mm. Analysis showed that the C content of the alloy was below 10ppm, whereas the C content of the copper alloy product smelted with the graphite crucible without splitting was above 100ppm.

The foregoing is illustrative of the best mode of the invention, and details not described herein are within the common general knowledge of a person of ordinary skill in the art. The protection scope of the present invention is subject to the content of the claims, and any equivalent transformation based on the technical teaching of the present invention is also within the protection scope of the present invention.

Claims (10)

1. A novel crucible with electromagnetic penetration and magnetic suspension capabilities comprises a crucible wall and a crucible bottom, wherein a coating is prepared on the inner wall of the crucible, and an induction coil is surrounded on the outer side of the crucible wall;

the crucible is made of metal or graphite;

the crucible is characterized in that the crucible is provided with a cutting seam along the height direction of the crucible, so that the crucible is in a structure formed by combining a plurality of flaps, and the cutting seam between the adjacent flaps forms a gap.

2. The crucible as set forth in claim 1, wherein: the metal is a metal or alloy with a melting point higher than the melting point of the material to be smelted by more than 300 ℃.

3. The crucible as set forth in claim 1, wherein: the width of the gap varies in the height direction of the crucible.

4. The crucible of claim 1, wherein: and processing a groove on the outer wall of the gap of the crucible.

5. The crucible of claim 1, wherein: the slit extends from the highest point of the crucible to the lowest point of the crucible;

alternatively, the crucible is left at a certain height for a certain distance without opening the slot.

6. The crucible of claim 1 or 3, wherein: the gap is a diagonal, curved or serpentine line extending between the upper and lower end surfaces of the crucible.

7. The crucible as set forth in claim 1, wherein: the inner wall of the crucible bottom is a conical surface, a hemispherical surface, a spherical table surface or a paraboloid.

8. The crucible of claim 1, wherein: a crucible bottom induction coil is arranged below the crucible bottom.

9. The crucible as set forth in claim 8, wherein: the crucible and the induction coil are both configured into a shape with tapers, wherein the upper part of the crucible is larger than the lower part of the induction coil;

or the crucible wall and the induction coil are columnar, and the crucible bottom and the induction coil at the crucible bottom are configured into tapered shapes with large top and small bottom.

10. The crucible as set forth in claim 1, wherein: the upper opening of the crucible is provided with a metal or graphite crucible cover, and the crucible cover is provided with a flap structure by a slit.

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