A method for balancing the superheat temperature of the melt in an electromagnetic cold crucible and the interfacial reaction, and an electromagnetic cold crucible

Abstract

A method and an electromagnetic cold crucible for balancing the superheat temperature of the melt in the electromagnetic cold crucible and the interfacial reaction belong to the technical field of electromagnetic cold crucibles. The existing electromagnetic cold crucibles cannot increase the superheat temperature of the molten metal, which has a negative impact on the integrity of the casting filling. In a method of the present invention for balancing the superheat temperature of the melt in the electromagnetic cold crucible and the interfacial reaction, a thermal barrier layer is provided at the bottom of the crucible body, and the temperature of the thermal barrier layer is regulated by a water separator. While achieving heat preservation, the interfacial reaction of the thermal barrier layer is reduced to reduce the contamination of the thermal barrier layer to the molten metal and ensure that the metal at the bottom of the crucible body is nearly in a state without a solidified shell; an electromagnetic cold crucible with a large aspect ratio is placed in an ultra-high frequency alternating electromagnetic field, and the eddy current heat generated by the ultra-high frequency alternating electromagnetic field melts the metal to form a "hump"-shaped molten metal in the electromagnetic cold crucible to reduce the contact area between the molten metal and the inner wall of the electromagnetic cold crucible. The present invention is mainly used to increase the superheat temperature of the melt in the electromagnetic cold crucible.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic cold crucibles, and particularly relates to a method and an electromagnetic cold crucible for balancing the superheat temperature of the melt in an electromagnetic cold crucible and the interfacial reaction. Background Art

[0002] With the continuous development of induction melting technology, in the aspect of engineering application of metal forming, the electromagnetic cold crucible induction skull melting technology has been introduced into the melting and preparation process of highly reactive alloys, such as Ti alloys, Zr alloys, etc. As an advanced melting method, it can form a solidified shell layer outside the melt during the melting process, effectively preventing the pollution of the metal melt and the nucleation effect of the crucible wall; the accompanying electromagnetic force stirring can also effectively remove high-density inclusions and low-density inclusions inside the melt, promoting the purity of the melt. Its working principle is to place a copper crucible with slits inside an alternating electromagnetic field, and a cooling water channel is arranged inside the crucible, and the eddy current heat excited by the induction coil above the alloy is used to melt the metal; at the same time, the molten metal will present a soft contact or non-contact state when contacting the crucible, so as to ensure the pure state of the alloy melt. These characteristics also make it show significant advantages in the field of smelting of active metals and high-purity metals.

[0003] Due to the existence of the condensation shell, the alloy liquid is always in a solid / liquid equilibrium state, and the melt temperature is basically near the liquidus of the alloy. Although the interfacial reaction can be reduced, the superheat of the melt is low, and the casting filling ability is weak. When melting high-melting-point and highly reactive alloys with traditional crucibles, although the superheat of the melt can be guaranteed, it will lead to a more serious interfacial reaction, easily causing the problem of non-metallic element inclusions in the alloy liquid and polluting the alloy liquid. Therefore, the existing electromagnetic cold crucibles cannot balance the superheat temperature of the metal melt and the interfacial reaction, which hinders the broad engineering application prospects of this technology. Summary of the Invention

[0004] The present invention aims to solve the problem of how to reduce the interfacial reaction while increasing the superheat of the melt to improve the purity and casting filling ability of the melt, and further provides a method and an electromagnetic cold crucible for balancing the superheat temperature of the melt in an electromagnetic cold crucible and the interfacial reaction. Under the synergistic effect of the thermal barrier layer and the water separator, and under the action of an ultra-high-frequency alternating electromagnetic field, while increasing the superheat temperature of the melt in the electromagnetic cold crucible, the interfacial reaction of the melt is also reduced, and the purity and casting filling ability of the melt are improved.

[0005] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0006] A method for balancing the superheat temperature of the melt in an electromagnetic cold crucible and the interfacial reaction, and the specific implementation process is as follows:

[0007] S1, sequentially arrange a thermal barrier layer and a water separator at the bottom of the crucible body;

[0008] S2. Place the crucible body with a large aspect ratio in the induction coil;

[0009] S3. Pass an ultra-high frequency current through the induction coil to generate an ultra-high frequency alternating electromagnetic field around the crucible body. The eddy current heat generated by the ultra-high frequency alternating electromagnetic field melts the metal, forming a "hump"-shaped metal melt in the electromagnetic cold crucible to reduce the contact area between the metal melt and the inner side wall of the electromagnetic cold crucible. At the same time, pass cooling water into the water distributor to control the temperature of the heat insulation layer by means of the water distributor. While achieving heat preservation, reduce the interfacial reaction of the heat insulation layer to reduce the pollution of the heat insulation layer to the metal melt and ensure that the metal at the bottom of the crucible body is in a semi-molten state.

[0010] An electromagnetic cold crucible, which comprises:

[0011] A crucible body, provided with a plurality of crucible segments along the circumferential direction. Each crucible segment is provided with a cooling water channel, and a slit is formed between two adjacent crucible segments;

[0012] A water distributor, arranged at the bottom of the crucible body and communicated with the cooling water channels of the crucible segments, for cooling the crucible body;

[0013] A heat insulation layer, arranged at the bottom of the crucible body and connected to the water distributor, for reducing the cooling of the water distributor to the metal melt at the inner bottom of the crucible body;

[0014] An induction coil, wound around the crucible body, for generating an ultra-high frequency alternating electromagnetic field;

[0015] After the metal material is put into the crucible body, an ultra-high frequency current is passed through the induction coil to generate an ultra-high frequency alternating electromagnetic field around the electromagnetic cold crucible. The eddy current heat generated by the ultra-high frequency alternating electromagnetic field melts the metal, and the water distributor passes cooling water into the cooling water channels of the crucible body to achieve the cooling of the crucible body.

[0016] Preferably, the ratio of the height of the crucible body to the outer diameter of the crucible body is greater than 5:2 to form a crucible body with a large aspect ratio, and the slit is less than 0.4 mm.

[0017] Preferably, the crucible body is a bottomless crucible. The top of the water distributor is inserted into the crucible body from the bottom of the crucible body, and the water distributor is detachably connected to the crucible body; the heat insulation layer is arranged at the top of the water distributor for reducing the cooling of the water distributor to the metal melt at the inner bottom of the crucible body.

[0018] Preferably, a plurality of micro-grooves are formed on the surface of the heat insulation layer. After the metal material in the crucible body is melted into a metal melt, the metal melt plugs the orifices of the micro-grooves to form a plurality of heat insulation air cavities with heat insulation effects in the heat insulation layer.

[0019] Preferably, a plurality of micro-grooves are formed on the surface of the thermal barrier layer, and the micro-grooves are filled with a thermal barrier material to achieve the thermal barrier effect.

[0020] Preferably, the thermal resistance material is one of quartz, corundum, and boron nitride.

[0021] Preferably, the micro-grooves are arranged in an array.

[0022] Preferably, the micro-groove is one of a square groove, a trapezoidal groove, and a semi-circular groove.

[0023] Preferably, the water separator includes:

[0024] An inlet chamber for introducing cooling water;

[0025] A cold water chamber inserted into the crucible body;

[0026] A connecting pipe, one end of which is disposed in the inlet chamber, and the other end is inserted into the cold water chamber and extends towards the bottom of the crucible body;

[0027] A return water chamber for discharging the cooling water;

[0028] A return water pipe inserted into the cooling water channel of the crucible body and connecting the cooling water channel and the return water chamber;

[0029] Cooling water is injected into the inlet chamber, and the cooling water flows from the connecting pipe to the cold water chamber and flushes the top surface of the cold water chamber to cool down the thermal barrier layer; after the cooling water flows from the cold water chamber to the cooling water channel and the return water pipe of the crucible body, it is discharged from the return water chamber to achieve the cooling of the crucible body.

[0030] The beneficial effects of the present invention compared with the prior art are as follows:

[0031] The present invention uses a thermal barrier layer to separate the water separator from the molten metal at the bottom of the electromagnetic cold crucible, increasing the thermal resistance between the water separator and the bottom of the melt. When the water separator regulates the temperature of the thermal barrier layer, a gradient temperature is formed from top to bottom in the thermal barrier layer. The temperature of the surface of the thermal barrier layer in contact with the molten metal is high, which increases the temperature of the molten metal at the bottom of the crucible body, making the solidified shell below the melt nearly disappear. While the temperature of the surface of the thermal barrier layer in contact with the water separator is low. By selecting a thermal resistance material with a small reaction degree and combining the cooling water flow rate and the arrangement mode of the thermal resistance material to comprehensively control the temperature of the thermal resistance material, the reaction kinetics process of the thermal barrier layer is controlled, thereby reducing the interfacial reaction on the surface of the thermal barrier layer in contact with the molten metal, reducing the contamination of the thermal barrier layer to the molten metal, and improving the purity of the melt. Therefore, under the synergistic effect of the thermal barrier layer and the water separator in the present application, while increasing the superheat of the melt at the bottom of the electromagnetic cold crucible, the interfacial reaction is reduced, and the purity of the melt and the casting filling ability are improved.

[0032] In addition, the magnetic field intensity of the ultra-high frequency alternating electromagnetic field is relatively strong, which can increase the electromagnetic force acting on the molten metal, further enhancing the tendency of the molten metal to converge towards the center of the electromagnetic cold crucible, forming a "hump" shape. Moreover, the ultra-high frequency alternating electromagnetic field can cause the molten metal to form a larger and more stable "hump", further reducing the contact area between the molten metal and the inner side wall of the electromagnetic cold crucible, thereby reducing the heat loss of the molten metal and increasing the superheat temperature of the molten metal. Since the molten metal is in a non-contact state with the side wall of the electromagnetic cold crucible, the occurrence of interfacial reactions is avoided, and the purity of the melt is improved. The electromagnetic cold crucible adopts a large aspect ratio structure. Under the condition of the existence of the melt "hump", the temperature gradient of the melt increases from bottom to top, further increasing the superheat temperature of the melt. Therefore, under the combined action of the thermal insulation layer, the water separator and the ultra-high frequency alternating electromagnetic field, not only the superheat temperature of the molten metal is increased, the casting filling ability is improved, but also the interfacial reaction between the electromagnetic cold crucible and the molten metal is reduced, and the purity of the molten metal is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, as part of this application, are used to provide a further understanding of the present invention.

[0034] Figure 1 It is a three-dimensional structural schematic diagram of the electromagnetic cold crucible of the present invention.

[0035] Figure 2 It is a sectional view of the electromagnetic cold crucible of the present invention.

[0036] Figure 3 It is a schematic diagram of three structural forms of the thermal insulation layer, where (a) is the thermal insulation layer with square micro-grooves, (b) is the thermal insulation layer with trapezoidal micro-grooves, and (c) is the thermal insulation layer with semi-circular micro-grooves.

[0037] Figure 4 It is a top view of the thermal insulation layer.

[0038] Figure 5 It is the temperature change gradient inside the thermal insulation layer when the electromagnetic cold crucible is working.

[0039] Figure 6 As the water flow rate of the water separator gradually increases, the temperature of the thermal insulation layer gradually decreases along the arc length.

[0040] Figure 7 It is a schematic diagram of the thermal insulation layer achieving the thermal resistance effect by using the heat insulation air cavity.

[0041] Description of the reference numerals: 1 - crucible body; 1-1 - crucible segment; 1-2 - cooling water channel; 2 - water distributor; 2-1 - water inlet pipe; 2-2 - water inlet chamber; 2-3 - cold water chamber; 2-4 - return water chamber; 2-5 - connecting pipe; 2-6 - return water pipe; 2-7 - drain pipe; 2-8 - pressure regulating valve; 2-9 - flow dividing plate; 3 - thermal insulation layer; 3-1 - microgroove; 4 - induction coil. Specific implementation mode

[0042] The following is a detailed description of the present invention by combining specific embodiments.

[0043] Embodiment 1:

[0044] A method for balancing the overheating temperature of the melt in an electromagnetic cold crucible and the interfacial reaction in this embodiment is specifically implemented as follows:

[0045] S1, the thermal insulation layer 3 and the water distributor 2 are sequentially arranged at the bottom of the crucible body 1;

[0046] S2, the crucible body 1 with a large aspect ratio is placed in the induction coil 4;

[0047] S3, the induction coil 4 is passed through with ultra-high frequency current to generate an ultra-high frequency alternating electromagnetic field around the crucible body 1. The eddy current heat generated by the ultra-high frequency alternating electromagnetic field melts the metal, and a "hump"-shaped metal melt is formed in the electromagnetic cold crucible to reduce the contact area between the metal melt and the inner wall of the electromagnetic cold crucible. At the same time, cooling water is introduced into the water distributor 2, and the temperature of the thermal insulation layer 3 is regulated by the water distributor 2 to form a gradient temperature from top to bottom in the thermal insulation layer 3. While achieving heat preservation, the interfacial reaction of the thermal insulation layer 3 is reduced to reduce the pollution of the thermal insulation layer to the metal melt and ensure that the metal at the bottom of the crucible body 1 is nearly in a non-solidified shell state.

[0048] In this embodiment, the thermal insulation layer 3 is used to separate the water distributor 2 from the metal melt at the bottom of the crucible in the electromagnetic cold crucible, increasing the thermal resistance between the water distributor and the bottom of the melt. When the water distributor regulates the temperature of the thermal insulation layer, a gradient temperature is formed from top to bottom in the thermal insulation layer, as Figure 5 shown. That is to say, the temperature of the side of the thermal insulation layer in contact with the metal melt is high. Compared with the traditional copper crucible bottom, the temperature of the metal melt at the bottom of the crucible body is increased, ensuring that the metal at the bottom of the crucible body is nearly in a non-solidified shell state. And the temperature of the side of the thermal insulation layer in contact with the water distributor is low. Under the cooling effect of the water distributor, the reaction kinetic characteristics of the thermal insulation layer are reduced, thereby reducing the interfacial reaction on the side of the thermal insulation layer in contact with the metal melt, reducing the pollution of the thermal insulation layer to the metal melt, and improving the purity of the melt. Therefore, the induction melting technology in this embodiment, under the synergistic effect of the thermal insulation layer 3 and the water distributor 2, improves the overheating of the melt at the bottom of the electromagnetic cold crucible, reduces the interfacial reaction, improves the purity of the melt and the casting filling ability.

[0049] In addition, the magnetic field intensity of the ultra-high frequency alternating electromagnetic field is relatively strong, which can increase the electromagnetic force acting on the molten metal, causing the molten metal to converge towards the center of the electromagnetic cold crucible to form a "hump" shape. Moreover, the ultra-high frequency alternating electromagnetic field can make the molten metal form a larger and more stable "hump", that is, the molten metal inside the electromagnetic crucible body 1 is overall similar to a metal column, and the diameter of the metal column gradually decreases from bottom to top. In this way, the contact area between the molten metal and the inner wall of the electromagnetic cold crucible is reduced, thereby reducing the heat loss of the molten metal and increasing the superheat temperature of the molten metal. The molten metal is in a non-contact state with the side wall of the electromagnetic cold crucible, avoiding the occurrence of interfacial reactions and improving the purity of the melt. The electromagnetic cold crucible adopts a large aspect ratio structure, which can raise the height of the "hump"-shaped molten metal, making the temperature gradient of the melt increase from bottom to top and further increasing the superheat temperature of the melt.

[0050] Therefore, under the combined action of the thermal insulation layer 3, the water separator 2 and the ultra-high frequency alternating electromagnetic field in this embodiment, not only the superheat temperature of the molten metal is increased, the casting filling ability is improved, but also the interfacial reaction between the electromagnetic cold crucible and the molten metal is reduced, and the purity of the molten metal is improved.

[0051] Embodiment 2:

[0052] See Figure 2 , an electromagnetic cold crucible in this embodiment includes a crucible body 1 for filling metal materials. A plurality of crucible segments 1-1 are arranged along the circumferential direction on the crucible body 1. A cooling water channel 1-2 is opened in each crucible segment 1-1. When cooling water is introduced into the cooling water channel 1-2, the temperature of the crucible body 1 can be reduced to prevent the crucible from burning out. A slit is formed between two adjacent crucible segments 1-1, and the slit is less than 0.4 mm. The ultra-high frequency alternating electromagnetic field enters the crucible body 1 from the slit, and an eddy current heat is formed in the crucible body 1 to melt the metal materials put into the crucible body 1 into a molten metal. The crucible body 1 is made of high-purity copper. In addition, the ratio of the height of the crucible body 1 to the outer diameter of the crucible body 1 is greater than 5:2 to form a crucible body 1 with a large aspect ratio.

[0053] To achieve the cooling of the crucible body 1, the electromagnetic cold crucible further includes a water separator 2. The cross-section of the water separator 2 is "convex"-shaped. The crucible body 1 is a bottomless crucible, that is, the crucible body 1 only has a crucible wall. The water separator 2 is arranged at the bottom of the crucible body 1, and the top convex part of the water separator 2 is inserted into the crucible body 1 from the bottom opening of the crucible body 1. The water separator 2 and the crucible body 1 are detachably connected, preferably by screws. A sealing gasket is arranged at the connection between the water separator 2 and the crucible body 1 to achieve a sealing effect.

[0054] Specifically, as Figure 2As shown, the water divider 2 includes a water inlet pipe 2-1, a water inlet chamber 2-2, a cold water chamber 2-3, a return water chamber 2-4, a connecting pipe 2-5, a return water pipe 2-6, a drain pipe 2-7, a pressure regulating valve 2-8, and a flow dividing plate 2-9. The cold water chamber 2-3, the return water chamber 2-4, and the water inlet chamber 2-2 are arranged in sequence from top to bottom. The water inlet pipe 2-1 is connected to the water inlet chamber 2-2, and cooling water is introduced into the water inlet chamber 2-2. The lower pipe orifice of the connecting pipe 2-5 is located in the water inlet chamber 2-2. The upper end of the connecting pipe 2-5 penetrates through the return water chamber 2-4 and is inserted into the cold water chamber 2-3. The upper pipe orifice of the connecting pipe 2-5 is close to the top of the cold water chamber 2-3 and is connected to the flow dividing plate 2-9. The flow dividing plate 2-9 and the inner wall of the cold water chamber 2-3 form an annular opening. The cooling water in the water inlet chamber 2-2 enters the cold water chamber 2-3 via the connecting pipe 2-5. Since the cold water chamber 2-3 of the water divider 2 is inserted into the crucible body 1, the cooling water flowing out of the connecting pipe 2-5 directly flushes the top of the cold water chamber 2-3 to reduce the temperature of the thermal insulation layer. By adjusting the water flow rate flowing out of the connecting pipe 2-5, the temperature of the thermal insulation layer 3 is regulated. The cooling water flowing out of the connecting pipe 2-5 diffuses outward along the flow dividing plate 2-9 and flows into the cold water chamber 2-3. The cold water chamber 2-3 is communicated with the lower opening of the cooling water channel 1-2. The cooling water enters the cooling water channel 1-2 via the cold water chamber 2-3 and cools the crucible wall to prevent the crucible wall from burning out. The return water pipe 2-6 communicates the cooling water channel 1-2 with the return water chamber 2-4. The top end of the return water pipe 2-6 extends to the top of the cooling water channel 1-2. The bottom end of the return water pipe 2-6 penetrates through the cold water chamber 2-3 and is inserted into the return water chamber 2-4. The cooling water flows from the bottom opening of the cooling water channel 1-2 to the top, then flows from the opening at the top end of the return water pipe 2-6 to the bottom of the return water pipe 2-6, and finally flows into the return water chamber 2-4 and is discharged through the drain pipe 2-7 connected to the return water chamber 2-4. The design of the cooling water channel 1-2 and the return water pipe 2-6 effectively controls the temperature of the crucible wall. The pressure regulating valve 2-8 is installed on the drain pipe 2-7 and is used to adjust the water inlet flow rate, thereby controlling the temperature of the crucible body 1, making the solidified shell in the crucible body 1 in a critical state. Cooperating with the crucible body 1 with a large aspect ratio and the ultra-high frequency alternating electromagnetic field can increase the temperature gradient in the melt and increase the melt superheat.

[0055] As Figure 3 and Figure 4As shown in the figure, the electromagnetic cold crucible further includes a thermal barrier layer 3. The thermal barrier layer 3 is disposed on the top of the water separator 2 and used as the bottom of the crucible body 1. When the metal in the crucible body 1 melts, the thermal barrier layer 3 is in direct contact with the metal melt in the crucible body 1. The thermal barrier layer 3 is used to separate the water separator 2 from the metal melt at the bottom of the electromagnetic cold crucible, increasing the thermal resistance between the water separator 2 and the bottom of the melt. When the water separator 2 regulates the temperature of the thermal barrier layer 3, a gradient temperature is formed from top to bottom in the thermal barrier layer 3. That is to say, the temperature of the side of the thermal barrier layer 3 in contact with the metal melt is high. Compared with the traditional copper crucible bottom, the temperature of the metal melt at the bottom of the crucible body is increased, ensuring that the metal at the bottom of the crucible body is nearly in a state without a solidified shell. And the temperature of the side of the thermal barrier layer 3 in contact with the water separator 2 is low. Under the cooling effect of the water separator 2, the reaction kinetic characteristics of the thermal barrier layer 3 are reduced, thereby reducing the interfacial reaction on the side of the thermal barrier layer 3 in contact with the metal melt, so as to reduce the pollution of the thermal barrier layer 3 to the metal melt and improve the purity of the melt. Therefore, under the synergistic effect of the thermal barrier layer 3 and the water separator 2 in this embodiment, while increasing the superheat of the melt at the bottom of the electromagnetic cold crucible, the interfacial reaction is also reduced, and the purity of the melt and the casting filling ability are improved.

[0056] Since the thermal barrier layer 3 is installed on the top of the water separator 2, and the water separator 2 and the crucible body 1 are connected in a detachable manner. When the thermal barrier layer 3 needs to be replaced, the water separator 2 can be detached from the crucible body 1 to realize the replacement of the thermal barrier layer 3.

[0057] Specifically, as Figure 3 and Figure 4 shown, a plurality of micro-grooves 3-1 arranged in an array are formed on the surface of the thermal barrier layer 3. After the metal material in the crucible body 1 is melted into a metal melt, due to the certain viscosity of the metal melt, the metal melt only blocks the orifice of the micro-groove 3-1 and does not flow into the micro-groove 3-1. As Figure 7 shown, after the micro-groove 3-1 is blocked, a heat-insulating air cavity is formed, which has a heat-insulating effect and increases the thermal resistance between the crucible bottom and the water separator. In addition, a thermal barrier material can be filled in the micro-groove 3-1, including but not limited to materials with low thermal conductivity such as quartz, corundum, and boron nitride, to achieve a thermal barrier effect and increase the thermal resistance between the water separator and the bottom of the melt. As Figure 3 shown, the micro-groove 3-1 can be a square groove, a trapezoidal groove, a semi-circular groove, etc. As Figure 5 shown, when the electromagnetic cold crucible is working, because of the thermal resistance effect at the micro-groove, only the temperature at the micro-groove 3-1 is relatively high, which can avoid the overall temperature of the upper surface of the thermal barrier layer 3 being too high and generating an interfacial reaction. The micro-grooves of the thermal barrier layer 3 can be designed according to different metal materials.

[0058] In addition, when facing different metal materials, different thermal resistance materials need to be filled in the thermal barrier layer 3 to ensure that the standard reaction Gibbs free energy is greater than 0. The selection method of the thermal resistance materials is as follows:

[0059] S1. Assume that the thermal resistance material filled in the thermal barrier layer 3 is an oxide thermal resistance material (M x2 O y2 ), and the metal raw material is A x1 B y1 C z1 . The reaction type is a redox reaction, and the reaction equation between the metal raw material elements and the thermal resistance material is determined as follows:

[0060] a1A x1 +b1M x2 O y2 =c1A x1 O y2 +d1M x2

[0061] a2B y1 +b2M x2 O y2 =c2B y1 O y2 +d2M x2

[0062] a3C z1 +b3M x2 O y2 =c3C z1 O y2 +d3M x2

[0063] where a1, a2, a3, b1, b2, b3, c1, c2, c3, d1, d2, d3 are all balancing coefficients;

[0064] S2. Calculate the standard reaction Gibbs free energy:

[0065] For element A:

[0066] Δ r G m θ(A)=c1Δ f G m θ(A x1 O y2 )+d1Δ f G m θ(M x2 )-b1Δ f G m θ(M x2 O y2 )-a1Δ f G m θ(Ax1 )

[0067] For element B:

[0068] Δ r G m θ(B) = c2Δ f G m θ(B y1 O y2 ) + d2Δ f G m θ(M x2 ) - b2Δ f G m θ(M x2 O y2 ) - a2Δ f G m θ(B y1 )

[0069] For element C:

[0070] Δ r G m θ(C) = c3Δ f G m θ(C z1 O y2 ) + d3Δ f G m θ(M x2 ) - b3Δ f G m θ(M x2 O y2 ) - a3Δ f G m θ(C z1 )

[0071] S3, determine whether the standard reaction Gibbs free energy of each element is less than 0. If the standard reaction Gibbs free energy of any element is less than 0 during this process, it is considered that the reaction will occur, and the thermal resistance material in the thermal barrier layer 3 needs to be replaced, including but not limited to oxide thermal resistance materials, carbide thermal resistance materials, composite thermal resistance materials, etc.; until the standard reaction Gibbs free energy of each element and the thermal resistance material is greater than 0, then confirm the use of this thermal resistance material.

[0072] If Figure 2As shown, the electromagnetic cold crucible further includes an induction coil 4. The induction coil 4 is wound around the crucible body 1. After the metal material is put into the crucible body 1, an ultra-high frequency current is passed through the induction coil 4 to generate an ultra-high frequency alternating electromagnetic field around the electromagnetic cold crucible. The applied induction frequency is 120 kHz - 150 kHz. The eddy current heat generated by the ultra-high frequency alternating electromagnetic field melts the metal to form a "hump"-shaped metal melt in the crucible body 1. Since the magnetic field strength of the ultra-high frequency alternating electromagnetic field is relatively strong, the electromagnetic force on the metal melt is increased, so that the metal melt converges towards the center of the electromagnetic cold crucible to form a "hump" shape, that is, the metal melt in the electromagnetic crucible body 1 is overall similar to a metal column, and the diameter of the metal column gradually decreases from bottom to top. In this way, the contact area between the metal melt and the inner wall of the electromagnetic cold crucible is reduced, thereby reducing the heat loss of the metal melt and increasing the superheat temperature of the metal melt. The metal melt is in a non-contact state with the side wall of the electromagnetic cold crucible, avoiding the occurrence of interfacial reactions and improving the purity of the melt. The electromagnetic cold crucible adopts a large aspect ratio structure, which can raise the height of the "hump"-shaped metal melt, making the melt temperature increase gradually from bottom to top and further increasing the superheat temperature of the melt.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for balancing the superheat temperature of the melt in an electromagnetic cold crucible and the interfacial reaction, characterized in that, The specific implementation process is as follows: S1. The thermal insulation layer and the water separator are sequentially arranged at the bottom of the crucible body. The crucible body is a bottomless crucible. The top of the water separator is inserted into the crucible body from the bottom of the crucible body, and the water separator is detachably connected to the crucible body. The thermal insulation layer is arranged on the top of the water separator and is used to reduce the cooling of the bottom metal melt in the crucible body by the water separator. A plurality of micro-grooves are formed on the surface of the thermal insulation layer. After the metal material in the crucible body is melted into a metal melt, the metal melt blocks the openings of the micro-grooves to form a plurality of heat insulation air cavities with heat insulation effects in the thermal insulation layer. The ratio of the height of the crucible body to the outer diameter of the crucible body is greater than 5:2 to form a crucible body with a large aspect ratio, and the slit is less than 0.4 mm. S2. Place the crucible body with a large aspect ratio in the induction coil. S3. Pass an ultra-high frequency current through the induction coil to generate an ultra-high frequency alternating electromagnetic field around the crucible body. The eddy current heat generated by the ultra-high frequency alternating electromagnetic field melts the metal to form a "hump"-shaped metal melt in the electromagnetic cold crucible to reduce the contact area between the metal melt and the inner side wall of the electromagnetic cold crucible. At the same time, pass cooling water into the water separator, and use the water separator to control the temperature of the thermal insulation layer. While achieving heat preservation, reduce the interfacial reaction of the thermal insulation layer to reduce the pollution of the metal melt by the thermal insulation layer and ensure that the metal at the bottom of the crucible body is in a semi-molten state.

2. An electromagnetic cold crucible, characterized in that, A method for balancing the overheating temperature of the melt in the electromagnetic cold crucible and the interfacial reaction as claimed in claim 1, wherein the electromagnetic cold crucible comprises: A crucible body, provided with a plurality of crucible segments along the circumferential direction. Each crucible segment is provided with a cooling water channel, and a slit is formed between two adjacent crucible segments. The ratio of the height of the crucible body to the outer diameter of the crucible body is greater than 5:2 to form a crucible body with a large aspect ratio, and the slit is less than 0.4 mm. A water separator, arranged at the bottom of the crucible body and communicated with the cooling water channels of the crucible segments, and is used for cooling the crucible body. The crucible body is a bottomless crucible. The top of the water separator is inserted into the crucible body from the bottom of the crucible body, and the water separator is detachably connected to the crucible body. A thermal insulation layer, arranged on the top of the water separator, arranged at the bottom of the crucible body and connected to the water separator, and is used to reduce the cooling of the bottom metal melt in the crucible body by the water separator. A plurality of micro-grooves are formed on the surface of the thermal insulation layer. After the metal material in the crucible body is melted into a metal melt, the metal melt blocks the openings of the micro-grooves to form a plurality of heat insulation air cavities with heat insulation effects in the thermal insulation layer. An induction coil, wound around the crucible body, and is used to generate an ultra-high frequency alternating electromagnetic field. After the metal material is put into the crucible body, an ultra-high frequency current is passed through the induction coil to generate an ultra-high frequency alternating electromagnetic field around the electromagnetic cold crucible. The eddy current heat generated by the ultra-high frequency alternating electromagnetic field melts the metal, and the water separator passes cooling water into the cooling water channels of the crucible body to realize the cooling of the crucible body.

3. The electromagnetic cold crucible according to claim 2, characterized in that, The micro-grooves are filled with a thermal insulation material to achieve the thermal insulation effect.

4. An electromagnetic cold crucible according to claim 3, characterized in that, The thermal insulation material is one of quartz, corundum, and boron nitride.

5. An electromagnetic cold crucible according to claim 2 or 3, characterized in that, The micro-grooves are arranged in an array form.

6. An electromagnetic cold crucible according to claim 2 or 3, characterized in that, The micro-groove is one of a square groove, a trapezoidal groove, and a semi-circular groove.

7. An electromagnetic cold crucible according to claim 2, characterized in that, The described water separator includes: An inlet chamber for introducing cooling water; A cold water chamber inserted into the crucible body; A connecting pipe, one end of which is arranged in the inlet chamber, and the other end is inserted into the cold water chamber and extends towards the bottom of the crucible body; A return water chamber for discharging the cooling water; A return water pipe inserted into the cooling water channel of the crucible body and connecting the cooling water channel and the return water chamber; Cooling water is injected into the inlet chamber. The cooling water flows from the connecting pipe to the cold water chamber and flushes the top surface of the cold water chamber to cool the heat insulation layer. After the cooling water flows from the cold water chamber to the cooling water channel and the return water pipe of the crucible body, it is discharged from the return water chamber to achieve the cooling of the crucible body.

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