Method for balancing melt overheating temperature and interface reaction of electromagnetic cold crucible and electromagnetic cold crucible

Abstract

The invention discloses a method for balancing the melt overheating temperature and interface reaction of an electromagnetic cold crucible and the electromagnetic cold crucible, belongs to the technical field of electromagnetic cold crucibles, and aims to solve the problem that the existing electromagnetic cold crucible cannot increase the overheating temperature of a metal melt and has negative effects on the integrity of casting and mold filling. According to the method for balancing the overheating temperature and the interface reaction of the melt in the electromagnetic cold crucible, the heat blocking layer is arranged at the bottom of the crucible body, the temperature of the heat blocking layer is regulated and controlled through the water segregator, heat preservation is achieved, meanwhile, the interface reaction of the heat blocking layer is reduced, and the heat insulation effect is improved. Pollution of the heat blocking layer to metal melt is reduced, and it is guaranteed that metal at the bottom of the crucible body is almost in a skull-free state. An electromagnetic cold crucible with a large aspect ratio is placed in an ultrahigh-frequency alternating electromagnetic field, eddy current hot melting metal generated by the ultrahigh-frequency alternating electromagnetic field forms hump-shaped metal melt in the electromagnetic cold crucible, and therefore the contact area between the metal melt and the inner wall of the electromagnetic cold crucible is reduced. The method is mainly used for increasing the melt overheating temperature of the electromagnetic cold crucible.

Description

Technical Field

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

[0002] With the continuous development of induction melting technology, the electromagnetic cold crucible induction shell melting technology has been introduced into the melting and preparation process of highly reactive alloys, such as Ti alloys, Zr alloys, etc., in the field of engineering application metal forming. As an advanced melting method, it can form a solidified shell layer on the outside of the melt during the melting process, effectively preventing metal melt contamination and wall nucleation effect; the accompanying electromagnetic stirring can also effectively remove high-density inclusions and low-density inclusions inside the melt, making the melt pure. Its working principle is to place a copper crucible with a slit inside an alternating electromagnetic field, and a cooling water channel is provided in the crucible. 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 be in a soft contact or non-contact state when in contact with the crucible, thereby ensuring the purity of the alloy melt. These characteristics also make it show significant advantages in the field of active metal and high-purity metal smelting.

[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 alloy liquidus line. Although the interface reaction can be reduced, the melt overheating is low and the casting filling capacity is weak. The traditional crucible smelting of high melting point and highly reactive alloys can ensure the melt overheating, but it will lead to more serious interface reactions, which can easily cause the inclusion of non-metallic elements in the alloy liquid and cause alloy liquid contamination. Therefore, the existing electromagnetic cold crucible cannot balance the problem of overheating temperature and interface reaction of the metal melt, 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 interface reaction while increasing the superheat of the melt to improve the purity of the melt and the casting filling capacity, and further provides a method for balancing the superheat temperature and interface reaction of the electromagnetic cold crucible melt and an electromagnetic cold crucible. Under the synergistic effect of the thermal barrier layer and the water separator, and the action of the ultra-high frequency alternating electromagnetic field, the superheat temperature of the electromagnetic cold crucible melt is increased, and the melt interface reaction is reduced, thereby improving the purity of the melt and the casting filling capacity.

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

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

[0007] S1, placing a thermal barrier layer and a water separator at the bottom of the crucible body in sequence;

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

[0009] S3, an ultra-high frequency current is passed through the induction coil to generate an ultra-high frequency alternating electromagnetic field around the crucible body. The eddy current generated by the ultra-high frequency alternating electromagnetic field heats the molten metal, forming 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; at the same time, cooling water is passed into the water divider, and the temperature of the thermal barrier layer is regulated by the water divider. 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 is in a semi-molten state.

[0010] An electromagnetic cold crucible, the electromagnetic cold crucible comprising:

[0011] The crucible body is provided with a plurality of crucible petals along the circumferential direction, each crucible petal is provided with a cooling water channel, and a slit is formed between two adjacent crucible petals;

[0012] A water distributor is provided at the bottom of the crucible body and is connected to the cooling water channel of the crucible petal for cooling the crucible body;

[0013] The heat-blocking layer is arranged at the bottom of the crucible body and connected to the water distributor, and is used to reduce the cooling of the metal melt at the bottom of the crucible body by the water distributor;

[0014] An induction coil is wound around the crucible body and is used to generate an ultra-high frequency alternating electromagnetic field;

[0015] After the metal material is put into the crucible, 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 generated by the ultra-high frequency alternating electromagnetic field heats the melted metal, and the water distributor passes cooling water into the cooling water channel of the crucible to cool the crucible.

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

[0017] Preferably, 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 and the crucible body are detachably connected; the thermal barrier layer is arranged on the top of the water separator to reduce the cooling of the bottom molten metal in the crucible body by the water separator.

[0018] Preferably, the surface of the thermal barrier layer is provided with a plurality of micro grooves, and after the metal material in the crucible is melted into a metal melt, the metal melt seals the notches of the micro grooves to form a plurality of heat insulating air cavities with a heat insulating effect in the thermal barrier layer.

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

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

[0021] Preferably, the microgrooves are arranged in an array.

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

[0023] Preferably, the water divider comprises:

[0024] A water inlet cavity, used for introducing cooling water;

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

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

[0027] A water return chamber, used to discharge cooling water;

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

[0029] Cooling water is injected into the water 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 the thermal barrier layer; the cooling water flows from the cold water chamber to the cooling water channel and return pipe of the crucible body, and is discharged from the return water chamber to achieve cooling of the crucible body.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention uses a thermal barrier layer to separate the water separator from the metal melt at the bottom of the electromagnetic cold crucible, increase the thermal resistance between the water separator and the bottom of the melt, and when the water separator adjusts 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 side of the thermal barrier layer in contact with the metal melt is high, which increases the temperature of the metal melt at the bottom of the crucible body, so that the solidified shell below the melt reaches a state of nearly disappearance. The temperature of the side of the thermal barrier layer in contact with the water separator is low, and a thermal resistance material with a small degree of reaction is selected, and the temperature of the thermal resistance material is comprehensively controlled in combination with the cooling water flow and the arrangement of the thermal resistance material, thereby controlling the reaction kinetics of the thermal barrier layer, thereby reducing the interface reaction of the side of the thermal barrier layer in contact with the metal melt, so as to reduce the contamination of the metal melt by the thermal barrier layer and improve the purity of the melt. Therefore, the induction smelting technology of the present application, under the synergistic effect of the thermal barrier layer and the water separator, improves the overheating of the melt at the bottom of the electromagnetic cold crucible, and also reduces the interface reaction, improves the purity of the melt and the casting filling capacity.

[0032] In addition, the magnetic field strength of the ultra-high frequency alternating electromagnetic field is relatively strong, which increases the electromagnetic force on the metal melt, and can further enhance the tendency of the metal melt to converge to the center of the electromagnetic cold crucible to form a "hump" shape. The ultra-high frequency alternating electromagnetic field can make the metal melt form a larger and more stable "hump", and the contact area between the metal melt and the inner wall of the electromagnetic cold crucible is further reduced, thereby reducing the heat loss of the metal melt and increasing the overheating temperature of the metal melt. The metal melt and the side wall of the electromagnetic cold crucible are in a non-contact state, avoiding the occurrence of interface reaction and improving the purity of the melt. The electromagnetic cold crucible adopts a large aspect ratio structure, which makes the melt temperature increase from bottom to top under the condition of the melt "hump", further increasing the overheating temperature of the melt. Therefore, under the joint action of the thermal barrier layer, the water separator and the ultra-high frequency alternating electromagnetic field, the overheating temperature of the metal melt is increased, the casting filling capacity is improved, and the interface reaction between the electromagnetic cold crucible and the metal melt is reduced, and the purity of the metal melt is improved. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0036] Figure 3 Schematic diagrams of three structural forms of thermal barrier layers, where (a) is a thermal barrier layer with square micro-grooves, (b) is a thermal barrier layer with trapezoidal micro-grooves, and (c) is a thermal barrier layer with semicircular micro-grooves.

[0037] Figure 4 A top view of the thermal barrier layer.

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

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

[0040] Figure 7 Schematic diagram of a thermal barrier layer using an insulating air cavity to achieve thermal resistance.

[0041] Explanation of the reference numerals: 1-crucible body; 1-1-crucible petal; 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 diverter plate; 3-thermal barrier layer; 3-1-micro groove; 4-induction coil. DETAILED DESCRIPTION

[0042] The present invention is described in detail below in conjunction with specific embodiments.

[0043] Embodiment 1:

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

[0045] S1, placing a heat barrier layer 3 and a water separator 2 at the bottom of a crucible body 1 in sequence;

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

[0047] S3, an ultra-high frequency current is passed through the induction coil 4 to generate an ultra-high frequency alternating electromagnetic field around the crucible body 1. The eddy current generated by the ultra-high frequency alternating electromagnetic field heats the molten metal, forming a "hump"-shaped metal melt 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 passed into the water divider 2, and the temperature of the thermal barrier layer 3 is regulated by the water divider 2 to form a gradient temperature from top to bottom in the thermal barrier layer 3, so as to achieve heat preservation while reducing the interface reaction of the thermal barrier layer 3, so as to reduce the contamination of the metal melt by the thermal barrier layer 3 and ensure that the metal at the bottom of the crucible body 1 is nearly in a non-condensed shell state.

[0048] In this embodiment, the water separator 2 is separated from the metal melt at the bottom of the electromagnetic cold crucible by a thermal barrier layer 3, thereby increasing the thermal resistance between the water separator and the bottom of the melt. When the water separator adjusts the temperature of the thermal barrier layer, a gradient temperature is formed from top to bottom in the thermal barrier layer, such as Figure 5 As shown, that is to say, the temperature of the side 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 compared to the traditional copper crucible bottom, ensuring that the metal at the bottom of the crucible body is close to a non-condensed shell state. The temperature of the side of the thermal barrier layer in contact with the water separator is low. Under the cooling effect of the water separator, the reaction kinetics of the thermal barrier layer are reduced, thereby reducing the interface reaction of the side of the thermal barrier layer in contact with the molten metal, thereby reducing the contamination of the molten metal by the thermal barrier layer and improving the purity of the melt. Therefore, the induction smelting technology of this embodiment, under the synergistic effect of the thermal barrier layer 3 and the water separator 2, improves the overheating of the melt at the bottom of the electromagnetic cold crucible, reduces the interface reaction, and improves the purity of the melt and the casting filling capacity.

[0049] In addition, the magnetic field strength of the ultra-high frequency alternating electromagnetic field is relatively strong, which increases the electromagnetic force on the metal melt, and can make the metal melt converge to the center of the electromagnetic cold crucible to form a "hump" shape, and the ultra-high frequency alternating electromagnetic field can make the metal melt form a larger and more stable "hump", that is, the metal melt in the electromagnetic crucible body 1 is similar to a metal column as a whole, and the diameter of the metal column gradually decreases from bottom to top, so that 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 overheating temperature of the metal melt. The metal melt and the side wall of the electromagnetic cold crucible are in a non-contact state, avoiding the occurrence of interface reaction 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, so that the melt temperature increases from bottom to top, further increasing the overheating temperature of the melt.

[0050] Therefore, under the combined action of the thermal barrier layer 3, the water separator 2 and the ultra-high frequency alternating electromagnetic field, this embodiment increases the superheat temperature of the molten metal, improves the casting filling capacity, reduces the interface reaction between the electromagnetic cold crucible and the molten metal, and improves the purity of the molten metal.

[0051] Embodiment 2:

[0052] See also Figure 2 An electromagnetic cold crucible of the present embodiment includes a crucible body 1 for filling metal materials. A plurality of crucible petals 1-1 are arranged on the crucible body 1 along the circumferential direction. A cooling water channel 1-2 is opened in each crucible petal 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. A slit is formed between two adjacent crucible petals 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. The ultra-high frequency alternating electromagnetic field forms eddy current heat in the crucible body 1 and melts the metal material put into the crucible body 1 into a metal melt. 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] In order to realize the cooling of the crucible body 1, the electromagnetic cold crucible also includes a water separator 2, the cross section of the water separator 2 is a "convex" shape, and 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 connected by screws, and 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, Figure 2As shown, the water distributor 2 includes an inlet pipe 2-1, an inlet chamber 2-2, a cold water chamber 2-3, a return chamber 2-4, a connecting pipe 2-5, a return pipe 2-6, a drain pipe 2-7, a pressure regulating valve 2-8 and a diverter plate 2-9. The cold water chamber 2-3, the return chamber 2-4 and the inlet chamber 2-2 are arranged in sequence from top to bottom. The inlet pipe 2-1 is connected to the inlet chamber 2-2 and cools the water into the inlet chamber 2-2. The lower pipe opening of the connecting pipe 2-5 is in the inlet chamber 2-2. The upper end of the connecting pipe 2-5 passes through the return chamber 2-4 and is inserted into the cold water chamber 2-4. In the water cavity 2-3, the upper pipe opening of the connecting pipe 2-5 is close to the top of the cold water cavity 2-3 and connected to the diverter plate 2-9. The diverter plate 2-9 and the inner wall of the cold water cavity 2-3 form an annular opening. The cooling water of the water inlet cavity 2-2 enters the cold water cavity 2-3 through the connecting pipe 2-5. Since the cold water cavity 2-3 of the water distributor 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 cavity 2-3 to reduce the temperature of the thermal barrier layer. The temperature of the thermal barrier layer 3 is regulated by adjusting the water flow rate flowing out of the connecting pipe 2-5. The cooling water flowing out of the connecting pipe 2-5 diffuses outward along the diverter plate 2-9 and flows into the cold water cavity 2-3. The cold water cavity 2-3 is connected with the lower opening of the cooling water channel 1-2. The cooling water enters the cooling water channel 1-2 through the cold water cavity 2-3 and cools the crucible wall to prevent the crucible wall from burning. The return pipe 2-6 is connected to the cooling water channel 1-2 and the return water chamber 2-4. The top of the return pipe 2-6 extends to the top of the cooling water channel 1-2. The bottom of the return pipe 2-6 runs 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, and then flows from the opening at the top of the return pipe 2-6 to the bottom of the return pipe 2-6, and finally flows into the return water chamber 2-4, and is discharged by 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 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 to adjust the water inlet flow rate, thereby controlling the temperature of the crucible body 1, so that the solidified shell in the crucible body 1 is in a critical state. 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 overheating.

[0055] like Figure 3 and Figure 4As shown, the electromagnetic cold crucible also includes a thermal barrier layer 3, which is arranged 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 is melted, the thermal barrier layer 3 directly contacts the molten metal in the crucible body 1, and the thermal barrier layer 3 is used to separate the water separator 2 from the molten metal at the bottom of the electromagnetic cold crucible, thereby increasing the thermal resistance between the water separator 2 and the bottom of the melt. When the water separator 2 adjusts 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, the temperature of the side of the thermal barrier layer 3 in contact with the molten metal is high, which increases the temperature of the molten metal at the bottom of the crucible body compared to the traditional copper crucible bottom, thereby ensuring that the metal at the bottom of the crucible body is close to a non-condensed shell state. 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 kinetics of the thermal barrier layer 3 is reduced, thereby reducing the interface reaction of the side of the thermal barrier layer 3 in contact with the metal melt, thereby reducing the contamination of the metal melt by the thermal barrier layer 3 and improving the purity of the melt. Therefore, the induction melting technology of this embodiment, under the synergistic effect of the thermal barrier layer 3 and the water separator 2, improves the overheating of the melt at the bottom of the electromagnetic cold crucible, reduces the interface reaction, and improves the purity of the melt and the casting filling capacity.

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

[0057] Specifically, Figure 3 and Figure 4 As shown, the surface of the heat-blocking layer 3 is provided with a plurality of micro grooves 3-1 arranged in an array. After the metal material in the crucible body 1 is melted into a metal melt, the metal melt only blocks the notch of the micro groove 3-1 and does not flow into the micro groove 3-1 because the metal melt has a certain viscosity. Figure 7 As shown, the micro groove 3-1 is blocked to form an insulating air cavity, which has a heat insulating effect and increases the thermal resistance between the bottom of the crucible and the water separator. In addition, the micro groove 3-1 can be filled with a heat-insulating material, including but not limited to quartz, corundum, boron nitride and other materials with low thermal conductivity, to achieve a heat-insulating effect and increase the thermal resistance between the water separator and the bottom of the melt. Figure 3 As shown, the micro groove 3-1 can be a square groove, a trapezoidal groove or a semicircular groove. Figure 5 As shown, when the electromagnetic cold crucible is working, because the micro-grooves have a thermal resistance effect, the temperature is relatively high only at the micro-grooves 3-1, so that the overall temperature of the upper surface of the thermal barrier layer 3 is prevented from being too high to produce an interface 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 method for selecting the thermal resistance material is as follows:

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

[0060] a1 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] 3C z1 +b3M x2 O y2 =c3C z1 O y2 +d3M x2

[0063] Among them, 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 the A element:

[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 the C element:

[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, judging whether the standard reaction Gibbs free energy of each element is less than 0. If the standard reaction Gibbs free energy of any element in this process is less than 0, 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, it is confirmed to use the thermal resistance material.

[0072] like Figure 2As shown, the electromagnetic cold crucible also includes an induction coil 4, which is wound around the crucible body 1. After the metal material is put into the crucible body 1, the induction coil 4 is passed through an ultra-high frequency current to generate an ultra-high frequency alternating electromagnetic field around the electromagnetic cold crucible. The applied induction frequency is 120kHz-150kHz. 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 intensity of the ultra-high frequency alternating electromagnetic field is relatively strong, the electromagnetic force exerted on the metal melt is increased, and the metal melt can be brought together to the center of the electromagnetic cold crucible to form a "hump" shape, that is, the metal melt in the electromagnetic crucible body 1 is similar to a metal column as a whole, and the diameter of the metal column gradually decreases from bottom to top, so that 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 overheating temperature of the metal melt. The metal melt and the side wall of the electromagnetic cold crucible are in a non-contact state, avoiding the occurrence of interface reaction 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, so that the melt temperature increases gradually from bottom to top, further increasing the melt superheat temperature.

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

Claims

1. A method for balancing the superheat temperature of an electromagnetic cold crucible melt and an interface reaction, characterized in that: The specific implementation process is as follows: S1, placing a thermal barrier layer and a water separator at the bottom of the crucible body in sequence; S2, placing the crucible body with a large aspect ratio in the induction coil; S3, an ultra-high frequency current is passed through the induction coil to generate an ultra-high frequency alternating electromagnetic field around the crucible body. The eddy current generated by the ultra-high frequency alternating electromagnetic field heats the molten metal, forming 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; at the same time, cooling water is passed into the water divider, and the temperature of the thermal barrier layer is regulated by the water divider. While achieving heat preservation, the interface 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 is in a semi-molten state.

2. An electromagnetic cold crucible, characterized in that: Used to implement the method for balancing the overheating temperature of the electromagnetic cold crucible melt and the interface reaction as described in claim 1, the electromagnetic cold crucible comprises: The crucible body is provided with a plurality of crucible petals along the circumferential direction, each crucible petal is provided with a cooling water channel, and a slit is formed between two adjacent crucible petals; A water distributor is provided at the bottom of the crucible body and is connected to the cooling water channel of the crucible petal for cooling the crucible body; The heat-blocking layer is arranged at the bottom of the crucible body and connected to the water distributor, and is used to reduce the cooling of the metal melt at the bottom of the crucible body by the water distributor; An induction coil is 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, 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 generated by the ultra-high frequency alternating electromagnetic field heats the melted metal, and the water distributor passes cooling water into the cooling water channel of the crucible to cool the crucible.

3. An electromagnetic cold crucible according to claim 2, characterized in that: The ratio of the height of the crucible body to the outer diameter of the crucible body is greater than 5:2, so as to form a crucible body with a large aspect ratio, and the cutting seam is less than 0.4 mm.

4. An electromagnetic cold crucible according to claim 2, characterized in that: 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 and the crucible body are detachably connected; the thermal barrier layer is arranged on the top of the water separator to reduce the cooling of the bottom metal melt in the crucible body by the water separator.

5. An electromagnetic cold crucible according to claim 4, characterized in that: The surface of the heat barrier layer is provided with a plurality of micro grooves. After the metal material in the crucible is melted into a metal melt, the metal melt seals the notches of the micro grooves to form a plurality of heat insulating air cavities with heat insulating function in the heat barrier layer.

6. An electromagnetic cold crucible according to claim 4, characterized in that: The surface of the heat-blocking layer is provided with a plurality of micro-grooves, and the micro-grooves are filled with heat-blocking materials to achieve a heat-blocking effect.

7. An electromagnetic cold crucible according to claim 6, characterized in that: The thermal resistance material is one of quartz, corundum and boron nitride.

8. An electromagnetic cold crucible according to claim 5 or 6, characterized in that: The micro grooves are arranged in the form of an array.

9. An electromagnetic cold crucible according to claim 5 or 6, characterized in that: The micro groove is one of a square groove, a trapezoidal groove and a semicircular groove.

10. The electromagnetic cold crucible according to claim 2, characterized in that: The water divider comprises: A water inlet cavity, used for introducing cooling water; A cold water chamber, inserted into the crucible body; A connecting pipe, one end of which is arranged in the water inlet cavity, and the other end of which is inserted into the cold water cavity and extends to the bottom of the crucible body; A water return chamber, used to discharge cooling water; A water return pipe is inserted into the cooling water channel of the crucible body and connects the cooling water channel with the water return chamber; Cooling water is injected into the water 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 the thermal barrier layer; the cooling water flows from the cold water chamber to the cooling water channel and return pipe of the crucible body, and is discharged from the return water chamber to achieve cooling of the crucible body.

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