High-purity vacuum induction melting furnace

Abstract

The utility model provides a high-purity vacuum induction melting furnace, which comprises a furnace body and a vacuum system, and is characterized by further comprising a melting component, a blanking guide piece and a forming die which are arranged in the furnace body, the melting assembly comprises a smelting crucible and an induction coil arranged on the outer side of the smelting crucible, the blanking guide piece is arranged at the bottom of the smelting crucible, and a through hole is formed in the blanking guide piece to serve as a melt flow channel; the forming die is arranged below the melting assembly, the feeding end of the melt flow channel is communicated with the interior of the smelting crucible, and the discharging end of the melt flow channel is arranged opposite to a pouring inlet of the forming die. According to the utility model, the technical problem of impurity control in the amorphous alloy smelting process is solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of alloy smelting furnaces, and in particular relates to a high-purity vacuum induction smelting furnace. Background Art

[0002] Bulk amorphous alloys have the advantages of high strength, high hardness, high elasticity, and excellent corrosion resistance. They are widely used in consumer electronics, medical equipment, sporting goods, aerospace and other industries. The processing characteristics of bulk amorphous alloys are that they can be mass-produced by high-pressure casting, and have excellent product consistency, and can produce high-stability and high-performance products at extremely low costs. With the in-depth development of bulk amorphous alloys in various application fields, precision structural parts formed by bulk amorphous casting have become the first choice for structural parts in specific fields. In some areas where technological development is particularly rapid, the requirements for bulk amorphous alloy materials are becoming more and more stringent, and requirements for refined manufacturing have been put forward. For example, in the manufacture of precision appearance parts with high gloss requirements, or structural parts with extremely high fatigue resistance, the existing system of bulk amorphous alloy materials is difficult to meet their manufacturing needs, and further improvements are needed to the existing amorphous alloy materials.

[0003] Existing commercial bulk amorphous alloy materials mostly use zirconium-based amorphous systems. Zirconium-based amorphous materials have moderate cost and good performance, making them the first choice in the current market. In the prior art, a vacuum induction melting furnace is used to produce zirconium-based amorphous alloy materials, and the raw materials of zirconium-based amorphous alloys are subjected to high-temperature alloying treatment by medium-frequency induction heating to prepare a master alloy. The melting crucible used in the existing melting equipment is an oxide ceramic crucible. This crucible is not only inexpensive, but also enables the induction coil to directly induction heat the metal material in the crucible, so that the heating efficiency is high, the melting time is short, and it is easy to operate. However, in the process of pouring the molten metal into the oxide ceramic crucible, impurities on the surface of the molten metal are very easy to adhere to the inner wall and the pouring port of the ceramic crucible, which is easy to cause contamination of the molten metal after repeated use, and the oxide ceramic crucible itself may introduce trace element impurities that affect the quality of the alloy.

[0004] There are also some improved methods for oxide ceramic crucibles in the prior art, such as the method proposed in the Chinese patent application number 202110572911.1 entitled "An amorphous alloy cold wall crucible induction melting device and induction melting method". In this technical solution, a water-cooled copper crucible is used to replace the oxide ceramic crucible. On the one hand, the replacement method in the above technical solution requires the modification of the existing smelting furnace, and the water-cooled copper crucible is expensive, which will lead to a sharp increase in costs. On the other hand, the use of this technical solution cannot completely avoid the pollution caused by impurities on the surface of the molten liquid adhering to the inner wall of the crucible and the pouring mouth during the casting process. Summary of the invention

[0005] The utility model aims to provide a high-purity vacuum induction melting furnace, aiming to solve the technical problem of impurity control in the amorphous alloy melting process in the prior art.

[0006] In order to achieve the above utility model purpose, the technical solution adopted by the utility model is as follows:

[0007] The high-purity vacuum induction melting furnace provided in the utility model comprises a furnace body and a vacuum system, and also comprises a molten material assembly, a blanking guide and a forming mold arranged in the furnace body;

[0008] The molten material assembly comprises a smelting crucible and an induction coil arranged outside the smelting crucible, the material drop guide is installed at the bottom of the smelting crucible, and a through hole is opened on the material drop guide as a molten liquid flow channel;

[0009] The forming mold is arranged below the melt assembly, the feed end of the melt flow channel is communicated with the interior of the melting crucible, and the discharge end is arranged opposite to the inlet of the forming mold.

[0010] Different from the method of pouring out the molten metal from the smelting crucible after smelting in the prior art smelting process, the utility model adopts a method of setting a material drop guide at the bottom of the smelting crucible to guide the smelted molten metal to be directly discharged from the bottom of the crucible, so that the pure molten metal at the bottom is directly separated from the impurities floating on the surface of the molten metal to avoid the influence of the impurities.

[0011] Furthermore, the blanking guide includes a flow channel portion and a nesting portion, the flow channel portion includes a molten liquid flow channel, and the discharge end of the flow channel portion extends out of the bottom of the smelting crucible; the nesting portion is a clamping structure extending out of the side of the flow channel portion, and the clamping structure is clamped on the bottom of the smelting crucible.

[0012] The flow channel of the blanking guide is used to guide the flow direction of the alloy melt, so that the melt can be introduced from the bottom of the melting crucible to the forming mold at the bottom of the crucible according to the set position. When setting the flow channel, a clamping structure that can be clamped in the melting crucible should also be set on the side of the flow channel. This is because there will be thermal shock during the flow of the melt. Since the blanking guide and the melting crucible are separate structures, the blanking guide will be instantly deformed under thermal shock. If there is no clamping structure, there will be a risk of peeling off from the bottom of the crucible. The clamping structure can ensure that the overall position of the blanking guide does not change.

[0013] Preferably, the blanking guide is made of dense material, and its processing accuracy is higher than that of the melting crucible; the dense material is one of graphite material, silicon carbide material, silicon nitride material, titanium carbide material, and titanium nitride material.

[0014] The main reason for using the material drop guide and the melting crucible as a separate structure in the utility model is that the processing requirements of the melting crucible body and the material drop part are very different, and they are not suitable as an integrated structure. There is no shortage of smelting devices in the prior art that directly open the bottom of the melting crucible to discharge materials, but they have not been actually applied in industrial production. The reason is that the requirements for melting crucibles in industrialization are low cost and good thermal conductivity, so oxide crucibles are mostly used, and the characteristics of oxide crucibles themselves are that they are made by sintering, with low dimensional accuracy and rough surface, and oxide crucibles are fragile. Directly digging holes to flow out the molten liquid not only has high requirements for the processing of the flow hole, but because the oxide crucible is too rough, the bottom opening cannot be sealed at all, and the bottom of the crucible is easy to deform and break under the thermal shock of the molten liquid, not only can the smelting not be completed, but also the low cost advantage of the oxide crucible is lost. Although the above disadvantages can be overcome by using graphite, carbide, and nitride crucibles with high processing precision and not easy to break, the stirring force of amorphous materials during alloying and melting is insufficient due to the heating method of induction melting, and the impurities contained in the material itself cannot be completely floated to the surface. Such crucibles have poor thermal efficiency and long cycle time, and cannot meet the requirements of industrial melting. In the utility model, the melting crucible is made of ordinary materials, and a finely processed dense material guide is separately set at the bottom of the melting crucible to effectively solve the above problems.

[0015] Preferably, the utility model also includes a flow regulating rod suspended on the blanking guide and adapted for use therewith, which is used to block the molten liquid flow channel in the initial state and to adjust the molten liquid flow rate during discharge. The flow regulating rod includes an extension section, a blocking section, and a spherical portion connected in sequence; the extension section is provided with a connecting portion connected to a motion control device of the flow regulating rod, and the motion control device drives the flow regulating rod to move up and down along the smelting crucible; the blocking section is columnar and has a clearance fit with the molten liquid flow channel, and the clearance size is 0.02~0.5mm; the spherical portion is provided at the end of the flow regulating rod; and a throttling groove is also provided that passes through the blocking section and the spherical portion.

[0016] Preferably, the bottom of the melting crucible is provided with one or two blanking guides, and the number of the flow regulating rods is the same as the number of the blanking guides. In the casting of larger parts, or when a mold with two cavities is required, two blanking guides can be provided at the bottom of the melting crucible to improve casting efficiency. The number of blanking guides should not be greater than two, otherwise the flow of each molten liquid flow channel is prone to unevenness when the molten liquid is discharged.

[0017] Preferably, a transition portion is provided between the extension section and the plugging section. The processing precision of the extension section, the plugging section and the spherical portion of the flow regulating rod are different. The extension section is mainly used for connection and has a general processing precision, which can meet the requirements of being an extension structure. The plugging section and the spherical portion are used to block the molten liquid flow channel and have a high processing precision. The provision of a transition portion between the two can make the connection between the two smoother.

[0018] Preferably, the throttling groove is a linear groove or a wedge-shaped groove, and the throttling groove can adjust the flow rate of the molten metal flowing through the throttling groove during the up and down movement.

[0019] Preferably, the smelting crucible is a double-layer crucible, including an outer crucible and an inner crucible sleeved therein; the outer crucible is a ramming crucible, and the inner crucible is an oxide crucible, and the oxide crucible is one of a calcium oxide crucible, a magnesium oxide crucible, a silicon oxide crucible, an aluminum oxide crucible, and a zirconium oxide crucible.

[0020] Preferably, the preparation method of the outer crucible is: mix 60-75 parts of magnesia, 16-28 parts of sodium silicate, 8-12 parts of nano-silicon dioxide, and 5-8 parts of mullite powder by weight, wherein the average particle size of the magnesia is 0.2-2 mm, the average particle size of the nano-silicon dioxide is 80-100 nm, and the average particle size of the mullite powder is 0.05-0.2 mm; after the above-mentioned mixed powders are mixed evenly, pour 3-6% of water by weight of the mixed powder, mix the powder and water evenly, pound them into shape, and bake and dry them to obtain the outer crucible.

[0021] The utility model preferably adopts a double-layer composite melting crucible, the inner lining is an oxide crucible, and the outer layer is made of rammed crucible crushed materials poured and air-dried. In the alloy melting process, the effective power of induction heating can be directly applied to the material, thereby improving the efficiency of the melt and reducing energy consumption. Electromagnetic stirring can also be achieved during the heating process, so that the impurities inside the melt can fully float up and gather on the surface of the melt.

[0022] Preferably, a notch is provided at the top of the inner crucible near the pouring port of the outer crucible for easy dumping of waste, and a fixed angle is provided at the bottom of the outer crucible for reinforcing the outer crucible.

[0023] The utility model also provides a method for smelting using the above-mentioned high-purity vacuum induction melting furnace, comprising the following steps:

[0024] S1, after feeding materials into the melting crucible, the vacuum system is turned on to evacuate the furnace body, and after completion, the interior of the furnace body is filled with inert protective gas. In the initial state, the flow regulating rod is plugged into the blanking guide;

[0025] S2, turning on the induction coil to heat the melting crucible until the raw materials form a melt;

[0026] S3, reduce the heating power, let the molten metal stand, and allow the impurities in the molten metal to fully float to the surface;

[0027] S4, start the motion control device of the flow regulating rod, pull up the flow regulating rod at a set rate, so that the pure molten metal at the bottom of the melting crucible is injected into the molding mold cavity from the bottom of the melting crucible through the molten metal flow channel of the blanking guide;

[0028] S5, after casting is completed, clean the slag remaining at the bottom of the melting crucible.

[0029] The high purity vacuum induction melting furnace and melting method of the utility model have the following advantages:

[0030] 1. The technical solution of using a split structure and separate processing of the melting crucible and the blanking guide reduces the manufacturing cost of the melt assembly and can effectively achieve high-purity melting.

[0031] 2. The double-layer composite crucible structure is low-cost and can improve melting efficiency and reduce energy consumption.

[0032] 3. Through the cooperation of the flow regulating rod and the blanking guide, on the one hand, the sealing of the melt in the crucible can be achieved at a low cost, and on the other hand, the number of times and safety of the bottom pouring method of the oxide crucible can be improved.

[0033] 4. The smelting method of the utility model uses the method of bottom pouring to leave the surface impurities and slag at the bottom of the crucible or the head of the mold to be removed through the post-process, thereby achieving the purpose of removing material impurities and realizing high-purity smelting. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of the high purity vacuum induction melting furnace of the utility model;

[0035] Figure 2 This is one of the structural schematic diagrams of the melt assembly and the flow regulating rod in the utility model;

[0036] Figure 3 This is the second structural schematic diagram of the melt assembly and the flow regulating rod in the utility model;

[0037] Figure 4 This is one of the structural schematic diagrams of the flow regulating rod in the utility model;

[0038] Figure 5 for Figure 4 An enlarged schematic diagram of the structure within the middle dashed line;

[0039] Figure 6 This is the second structural schematic diagram of the flow regulating rod in the utility model;

[0040] Figure 7 for Figure 6 An enlarged schematic diagram of the structure within the middle dashed line;

[0041] Figure 8 This is the third structural schematic diagram of the melt assembly and the flow regulating rod in the utility model;

[0042] Description of Figure Numbers:

[0043] 101. furnace body; 102. casting mold; 103. vacuum system; 104. vacuum pipe; 105. air extraction port; 106. observation window; 107. sealing structure; 108. screw rod and slider structure; 109. hand wheel; 110. induction coil; 111. flow regulating rod;

[0044] 201, 301, outer crucible; 202, 302, inner crucible; 203, first fixed angle; 204, second fixed angle; 205, 307, 309, blanking guide; 206, 308, 310, melt flow channel; 207, melt impurities; 208, 216, blocking section; 209, 219, extension section; 210, 217, throttling groove; 211, 218, spherical part; 212, transition part; 213, 214, 305, 306, connecting part; 215, incision;

[0045] 303. A first flow regulating rod; 304. A second flow regulating rod. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and technical effect of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model is clearly and completely described. The embodiment described below is a part of the embodiment of the utility model, not all of the embodiments. In combination with the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model. If the specific conditions are not specified in the embodiment, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer; the reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially.

[0047] Unless the context clearly states otherwise, expressions in the singular form of a word should be understood to include the plural form of the word. The terms "include" or "have" are intended to specify the presence of a feature, quantity, step, operation, element, part, or combination thereof, but are not used to exclude the presence or possible addition of one or more other features, quantities, steps, operations, elements, parts, or combinations thereof.

[0048] The overall structural diagram of the high purity vacuum induction melting furnace provided by the embodiment of the utility model is shown in the attached figure. Figure 1As shown. The main structure of the smelting furnace includes a furnace body 101 and a vacuum system 103, and also includes a molten material assembly, a blanking guide and a forming mold 102 arranged in the furnace body. The forming mold 102 used in this embodiment is a casting mold. The furnace body 101 is a molten material bin, which is used to provide a suitable smelting environment for the smelting process. The vacuum system 103 uses a two-stage vacuum pumping system, which can draw a high vacuum in the furnace body 101. In the embodiment of the utility model, the inert protective gas system can adopt the inert gas intake protection system in the prior art, so it is not drawn in this embodiment. The vacuum system 103 is connected to the furnace body 101 through a vacuum pipe 104, and the exhaust port 105 in the furnace body 101 is used for vacuum exhaust. A transparent observation window 106 is provided on the top of the furnace body 101 for the operator to observe the smelting situation in the furnace at any time.

[0049] As attached Figure 2 To Attachment Figure 7 The figure shows the structure of the melt assembly and the flow regulating rod. Figure 1 The smelting furnace is further described with reference to other drawings.

[0050] The melt assembly includes a melting crucible and an induction coil 110 disposed outside the melting crucible. The material guide 205 is installed at the bottom of the melting crucible (such as the attached Figure 2 ), a through hole is provided on the blanking guide 205 as a molten metal flow channel 206. The forming mold 102 is arranged below the melt assembly, the feed end of the molten metal flow channel is communicated with the inside of the melting crucible, and the discharge end is arranged opposite to the inlet of the forming mold.

[0051] The melting crucible used in this embodiment is a double-layer crucible, including an outer crucible 201 and an inner crucible 202. The inner crucible 202 is an oxide crucible, preferably one of calcium oxide crucible, magnesium oxide crucible, silicon oxide crucible, aluminum oxide crucible, and zirconium oxide crucible.

[0052] The inner crucible selected in this embodiment is a calcium oxide crucible, and the outer crucible is prepared by ramming material outside the inner crucible. The preparation method of the outer crucible 201 can be referred to: 70 parts of magnesia, 24 parts of sodium silicate, 10 parts of nano silicon dioxide, and 5 parts of mullite powder are mixed by weight, wherein the average particle size of the magnesia is 1mm, the average particle size of the nano silicon dioxide is 90nm, and the average particle size of the mullite powder is 0.1mm. After the above-mentioned mixed powder is mixed evenly, water accounting for 5% of the weight of the mixed powder is poured in, and the powder and water are mixed evenly and then rammed into shape, and the outer crucible is obtained after baking and drying. The characteristics of the ramming crucible are low cost and simple preparation process, and there is no too strict requirement on the raw materials, that is, the raw material ratio, as long as it is within the ratio range of the utility model.

[0053] A notch 215 is provided at the top of the inner crucible 202 near the pouring port of the outer crucible 201 to facilitate dumping of waste materials and prevent the top of the crucible from being broken by thermal shock during dumping of waste materials. A first fixed angle 203 and a second fixed angle 204 are provided at the bottom of the outer crucible 201 to reinforce the crucible. The fixed angles can be made of a harder and more wear-resistant ceramic structure or metal structure.

[0054] As attached Figure 2 and attached Figure 3 The material guide 205 includes a flow channel portion and a nesting portion. The flow channel portion includes a melt flow channel 206, and the discharge end of the flow channel portion extends out of the bottom of the melting crucible. The nesting portion is a clamping structure extending from the side of the flow channel portion, and the clamping structure is clamped at the bottom of the melting crucible. The material guide 205 is preferably made of dense material, and its processing accuracy is higher than the processing accuracy of the melting crucible. The dense material is preferably one of graphite material, silicon carbide material, silicon nitride material, titanium carbide material, and titanium nitride material. The above materials have high processing accuracy, low surface energy, and are not easy to adhere to the melt.

[0055] Also used in conjunction with the blanking guide 205 is a flow regulating rod 111 suspended on the blanking guide 205 and adapted thereto.

[0056] As attached Figure 4 and attached Figure 5 , the flow regulating rod includes an extension section 209, a blocking section 208, and a spherical portion 211 connected in sequence. A connecting portion 213 is provided on the extension section 209 and is connected to the motion control device of the flow regulating rod. The motion control device used in this embodiment is a screw slider mechanism 108, and a hand wheel 109 is provided on it, and a sealing structure 107 is provided between the motion control device and the furnace body. By turning the hand wheel 109, the screw slider mechanism 108 drives the flow regulating rod 111 to move up and down along the smelting crucible. The blocking section 208 is columnar and has a clearance fit with the molten liquid flow channel 206, and the clearance size is 0.02~0.5mm, so that the blocking section can easily penetrate into the molten liquid flow channel, and the molten liquid will not leak out easily. The spherical portion 211 is arranged at the end of the flow regulating rod. A wedge-shaped throttling groove 210 is also provided to pass through the blocking section and the spherical portion. A transition portion 212 is also provided between the extension section 209 and the blocking section 208.

[0057] In another embodiment, as shown in the attached Figure 6 and attached Figure 7 The flow regulating rod includes an extension section 219, a material blocking section 216, and a spherical portion 218 connected in sequence. The extension section 219 is provided with a connecting portion 214 connected to the motion control device of the flow regulating rod, and is also provided with a linear throttling groove 217 that passes through the material blocking section and the spherical portion. The flow regulating rod can realize the opening and closing of the molten liquid in the melting crucible, and the throttling groove at the end thereof controls the flow rate of the molten liquid flowing out when it is opened or closed.

[0058] In another embodiment, as shown in the attached Figure 8 The bottom of the melting crucible composed of the outer crucible 301 and the inner crucible 302 is equipped with two material drop guides 307 and 309, and also equipped with a matching first flow regulating rod 303 and a second flow regulating rod 304. The connecting parts 305 and 306 are respectively connected to the motion control devices of the flow regulating rods 303 and 304. The flow of the molten liquid in the molten liquid flow channels 308 and 310 is controlled by using the material drop guides and the flow regulating rods.

[0059] Attach Figure 1 To Attachment Figure 3 For reference, the smelting method of the high-purity vacuum induction melting furnace in this embodiment includes the following steps:

[0060] S1, after feeding materials into the melting crucible, start the vacuum system 103 to evacuate the furnace body 101, and then fill the furnace body 101 with inert protective gas argon. Figure 3 In the initial state, the flow regulating rod is plugged into the blanking guide 205;

[0061] S2, turning on the induction coil 110 to heat the smelting crucible to melt the raw materials until they form a melt. The smelting power at this time is relatively high, and can be selected to be 100-200kw. In this process, rare earth metals such as yttrium and erbium or other deoxidizing slag-forming agents can also be added;

[0062] S3, reducing the heating power to 40-50kw for refining, and allowing the molten metal to stand to allow the impurities 207 in the molten metal to fully float to the surface;

[0063] S4, start the motion control device 108 of the flow regulating rod, and pull up the flow regulating rod (such as the attached Figure 2 ), so that the pure molten metal at the bottom of the melting crucible is injected into the cavity of the forming mold 102 from the bottom of the melting crucible through the molten metal flow channel 206 of the blanking guide;

[0064] S5, after casting is completed, clean the slag remaining at the bottom of the melting crucible.

[0065] The smelting method of the utility model uses the bottom pouring method to leave the surface impurities and scum at the bottom of the crucible or the material head part of the mold to be removed through the post-process, thereby achieving the purpose of removing material impurities and realizing high-purity smelting.

[0066] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A high purity vacuum induction melting furnace, comprising a furnace body and a vacuum system, characterized in that: It also includes a molten material assembly, a material drop guide and a forming die arranged in the furnace body; The molten material assembly comprises a smelting crucible and an induction coil arranged outside the smelting crucible, the material drop guide is installed at the bottom of the smelting crucible, and a through hole is opened on the material drop guide as a molten liquid flow channel; The forming mold is arranged below the melt assembly, the feed end of the melt flow channel is communicated with the interior of the melting crucible, and the discharge end is arranged opposite to the inlet of the forming mold.

2. The high purity vacuum induction melting furnace according to claim 1, characterized in that: The blanking guide comprises a flow channel portion and a nesting portion, the flow channel portion comprises a molten metal flow channel, and a discharge end of the flow channel portion extends out of the bottom of the smelting crucible; the nesting portion is a clamping structure extending out of the side of the flow channel portion, and the clamping structure is clamped on the bottom of the smelting crucible.

3. The high purity vacuum induction melting furnace according to claim 1, characterized in that: The material drop guide is made of dense material, and its processing accuracy is higher than that of the melting crucible; the dense material is one of graphite material, silicon carbide material, silicon nitride material, titanium carbide material, and titanium nitride material.

4. The high purity vacuum induction melting furnace according to claim 1, characterized in that: It also includes a flow regulating rod suspended on the blanking guide and adapted for use therewith, the flow regulating rod including an extension section, a blocking section, and a spherical portion connected in sequence; the extension section is provided with a connecting portion connected to a motion control device of the flow regulating rod, and the motion control device drives the flow regulating rod to move up and down along the smelting crucible; the blocking section is columnar and has a clearance fit with the molten liquid flow channel, and the clearance size is 0.02~0.5mm; the spherical portion is arranged at the end of the flow regulating rod; and a throttling groove penetrating the blocking section and the spherical portion is also provided.

5. The high purity vacuum induction melting furnace according to claim 4, characterized in that: The bottom of the smelting crucible is provided with one or two material dropping guides, and the number of the flow regulating rods is the same as the number of the material dropping guides.

6. The high purity vacuum induction melting furnace according to claim 4, characterized in that: A transition portion is also provided between the extension section and the material blocking section; and the throttling groove is a straight groove or a wedge-shaped groove.

7. The high purity vacuum induction melting furnace according to any one of claims 1 to 6, characterized in that: The smelting crucible is a double-layer crucible, including an outer crucible and an inner crucible sleeved therein; the outer crucible is a ramming crucible, and the inner crucible is an oxide crucible, and the oxide crucible is one of calcium oxide crucible, magnesium oxide crucible, silicon oxide crucible, aluminum oxide crucible, and zirconium oxide crucible.

8. The high purity vacuum induction melting furnace according to claim 7, characterized in that: A cutout is provided on the top of the inner crucible near the pouring port of the outer crucible.

9. The high purity vacuum induction melting furnace according to claim 8, characterized in that: The bottom of the outer crucible is provided with a fixed angle.

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