Suspension melting apparatus with combined cold crucible and crucible detachment casting method

Abstract

The application discloses a kind of suspension smelting equipment with combined cold crucible, cold crucible, induction coil and mould device are installed in vacuum chamber;Coaxial electrode extends from the outside of vacuum chamber into chamber, the part outside chamber is combined with the two electrodes of induction power supply, the part inside chamber is combined with the two electrodes of induction coil;Two side walls of vacuum chamber are respectively installed with the horizontal direction of crucible driving rod guide pipe, and dynamic sealing device is arranged in each crucible driving rod guide pipe;Cold crucible is composed of two half-crucibles symmetrical to left and right, crucible driving rod guide pipe is provided with crucible push rod, one end of crucible push rod is connected with half-crucible, the other end is connected with crucible moving device;The part outside coaxial electrode is also connected with electrode moving device, so that coaxial electrode is vertically moved under the drive of electrode moving device;Mould device is located directly below cold crucible.The equipment of the application can realize that there is no residual metal in crucible during casting process by separating two half-crucibles.

Description

Technical Field

[0001] This invention relates to the field of melting and casting equipment technology, specifically to a suspension melting equipment with a combined cold crucible and a crucible separation casting method. Background Technology

[0002] As an advanced technology for smelting high-end metallic materials, suspension smelting technology has received widespread attention in material preparation research and industrial production. During the application of this technology, some process problems related to this new technology have gradually emerged and need to be addressed one by one.

[0003] The core component of suspension melting is a cold metal crucible 01. During the melting process in the vacuum chamber 02, electromagnetic levitation ensures that the molten pool in the crucible is almost in contact with the crucible wall, which is crucial for the smooth progress of the melting process. However, during the tilting or bottom casting process after melting, the intense cooling effect of the crucible wall causes some of the molten metal 03 to solidify along the crucible wall as it flows downwards, affecting the material yield. This is especially true for small-sized crucibles, where the solidified shell can constitute a significant proportion. Since the materials melted by suspension melting are often very expensive, the material yield is of particular concern.

[0004] like Figure 1 As shown, the structure of a tilting casting device for suspension melting is generally quite complex. First, the cold crucible 01 needs to be tilted to pour the molten metal 03 into the casting mold 010, and the casting mold 010 needs to be offset vertically from the cold crucible 01, which undoubtedly requires the vacuum chamber 02 to have a sufficiently large space. Second, the cold crucible 01 needs to be equipped with a coolant pipe 08 and a cooling pipe interface 07 located in the furnace body of the vacuum chamber 02. Obviously, the tilting action of the cold crucible 01 requires the installation of a device (such as a bearing) in the cooling pipe interface 07 to allow the coolant pipe 08 to rotate flexibly, as well as to ensure the insulation of the coolant pipe 08 to the vacuum chamber 02 and the vacuum dynamic seal. Third, the tilting of the cold crucible 01 also requires the induction coil 04 surrounding the outside of the cold crucible 01 to tilt accordingly. Therefore, the coaxial electrode 05, which is coupled with the induction coil 04, also needs to have an electrode interface 06 installed in the furnace body of the vacuum chamber 02. Furthermore, a device (such as a bearing) needs to be installed within the electrode interface 06 to allow the coaxial electrode 05 to rotate flexibly, ensuring the insulation of the coaxial electrode 05 to the vacuum chamber 02 and the vacuum dynamic seal. Fourth, at least one drive device 09 is also required to drive the tilting action of the cold crucible 01 and the induction coil 04.

[0005] like Figure 2As shown, some suspension melting equipment uses bottom casting for the casting process. In this casting method, an opening 011 needs to be set at the bottom of the cold crucible 01, and a crucible plug 012 is installed in the opening 011. After melting, the crucible plug 012 is pulled down first, and then the molten metal 03 flows down from the opening 011 at the bottom of the cold crucible 01 into the casting mold 010 below the cold crucible 01. This method does not require a tilting drive device, nor does it require a rotating device in the electrode interface 06 and cooling pipe interface 07, so the structure of this casting method is simpler than tilting casting. However, the crucible plug 012 can cause some contamination to the molten pool. In addition, in order to maintain the temperature of the molten pool during bottom casting, the current of the induction coil 04 is generally not interrupted, and the electromagnetic field generated by it will cause the bottom casting liquid to scatter, thereby interfering with the casting process.

[0006] Therefore, how to provide a casting method that hardly forms a solidified shell and has a simple equipment structure, as well as a suspension melting equipment for this casting method, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention designs a suspension melting device with a combined cold crucible. This cold crucible consists of two symmetrical half-crucibles. After melting is completed, the two half-crucibles quickly separate, allowing the molten metal in the cold crucible to flow downwards into the mold from the bottom. This significantly simplifies the equipment structure and ensures that the molten metal in the cold crucible is almost completely injected into the mold, with minimal crust formation in the cold crucible.

[0008] The present invention provides a suspension melting device with a combined cold crucible, including a vacuum chamber, a cold crucible, an induction coil, a coaxial electrode, and a mold device;

[0009] The cold crucible, induction coil, and mold device are installed in the vacuum chamber, with the induction coil surrounding the outer circumference of the cold crucible and the mold device used to receive the molten metal inside the cold crucible.

[0010] The coaxial electrode extends from the outside of the vacuum chamber into the chamber, with the part outside the chamber connected to the two electrodes of the induction power supply and the part inside the chamber connected to the two electrodes of the induction coil.

[0011] The two side walls of the vacuum chamber are respectively equipped with horizontal crucible drive rod guides, and each crucible drive rod guide is equipped with a dynamic sealing device.

[0012] The cold crucible consists of two symmetrical half-crucibles. A crucible push rod is installed inside the crucible drive rod guide tube. One end of the crucible push rod is connected to the half-crucible, and the other end is connected to the crucible moving device.

[0013] The outer part of the coaxial electrode is also connected to the electrode moving device so that the coaxial electrode can move vertically under the drive of the electrode moving device;

[0014] The mold assembly is located directly below the cold crucible.

[0015] Furthermore, the semi-crucible is composed of several lobes whose length direction is parallel to the axis of the cold crucible, and the several lobes form the whole semi-crucible;

[0016] Each of the lobes has a cooling hole that connects to the coolant interface.

[0017] Furthermore, the cold crucible includes a half-crucible body, cooling tubes, a water jacket, a main cooling tube, and a vacuum hose;

[0018] The cooling holes of each lob are connected to the water jacket through cooling tubes. The water jacket is connected to the main cooling pipe. The main cooling pipe is connected to the coolant interface installed on the side wall of the vacuum chamber through a vacuum hose. The coolant interface is connected to the cooling system outside the vacuum chamber.

[0019] Furthermore, clamps are fixedly installed on the side of the water jacket of each half crucible, and a horizontally oriented crucible push rod is installed on the outside of each clamp. The crucible push rod extends away from the half crucible, passes through the crucible drive rod conduit installed on the side wall of the vacuum chamber, extends to the outside of the vacuum chamber through the dynamic sealing device in the tube, and is connected to the crucible moving device.

[0020] Furthermore, the cold crucible includes a half-crucible body, a cooling manifold, and a vacuum hose;

[0021] The cooling holes of each lobe of the semi-crucible body are connected end to end and connected to the coolant interface on the side wall of the vacuum chamber through a cooling main pipe and a vacuum hose.

[0022] Furthermore, a clamp is fixedly installed on the lower edge side of each half crucible, and a horizontally oriented crucible push rod is installed on the outside of each clamp. The crucible push rod extends away from the half crucible, passes through the crucible drive rod guide tube installed on the side wall of the vacuum chamber, extends to the outside of the vacuum chamber through the dynamic sealing device in the tube, and is connected to the crucible moving device.

[0023] Furthermore, electrode guide tubes are installed vertically on the furnace top or bottom, and insulating linings and dynamic sealing devices are installed in the electrode guide tubes.

[0024] The coaxial electrode is installed in the electrode conduit at the top or bottom of the furnace, and passes through the insulating lining and dynamic sealing device in the electrode conduit.

[0025] Furthermore, the coaxial electrode includes an inner electrode tube and an outer electrode tube, and cooling water flows through both electrode tubes. A sealing component is provided between the inner electrode tube and the outer electrode tube.

[0026] Outside the vacuum chamber, both the inner and outer electrode tubes are connected to the two electrodes of the induction power supply via a flexible cable through a cable interface, while cooling water is introduced into the coaxial electrode through an electrode water interface pipe.

[0027] Inside the vacuum chamber, the inner electrode tube and the outer electrode tube are connected to the two electrodes of the induction coil through the induction coil interface tube, respectively.

[0028] Furthermore, an insulating sleeve is fitted onto the outer circumference of the cold crucible, and its inner diameter matches the outer diameter of the cold crucible.

[0029] The upper edge of the insulating sleeve is provided with an annular flange, which is connected to the upper edge of the induction coil.

[0030] The present invention also provides a crucible separation casting method, using the above-mentioned suspension melting equipment, comprising the following steps:

[0031] S1. Before the smelting work begins, use the crucible moving device to push the two half crucibles together to form a whole cold crucible. Use the electrode moving device to move the induction coil to the position of the cold crucible. Put the insulating sleeve on the outside of the cold crucible and insert it between the cold crucible and the induction coil.

[0032] S2. After evacuation and filling with inert gas, the induction power supply is started to deliver high-frequency current to the induction coil. The material in the cold crucible is heated and melted under the action of the electromagnetic field.

[0033] S3. After the melting requirements are met, start the electrode moving device to make the induction coil and the insulating sleeve rise rapidly until the lower edge of the induction coil and the insulating sleeve is higher than the upper edge of the cold crucible, so that the two half crucibles are freed from the constraint of the insulating sleeve.

[0034] The lifting process of the induction coil is completed within seconds, preferably within seconds;

[0035] S4. Immediately start the crucible moving device to quickly separate the two half crucibles, allowing the molten metal in the crucibles to flow downwards into the mold device, completing the casting action;

[0036] The separation process of the two half crucibles should begin within seconds after the induction coil lifting process ends and be completed within seconds. Preferably, it should begin within seconds after the induction coil lifting process ends and be completed within seconds.

[0037] The advantages of this invention compared to the prior art are:

[0038] 1. This invention designs an apparatus and method for completing the casting process in a semi-crucible separation manner for suspension melting technology. Compared with the traditional tilting casting mode, the semi-crucible separation casting method requires a simpler equipment structure, makes vacuum sealing easier to achieve, and allows for a reduction in furnace size.

[0039] 2. Compared with the bottom casting mode, in the half-crucible separation casting method, the induction coil is raised above the crucible, and the electromagnetic field has almost no effect on the liquid flow, so it will not interfere with the casting process.

[0040] 3. In traditional tilting and bottom casting processes, the molten metal flows downwards along the cooling crucible wall, causing a solidified shell to form on the crucible wall, reducing material yield. The cooling of the molten metal also negatively impacts the material composition of the casting. In the semi-crucible separation casting process of this invention, the molten metal falls rapidly into the mold without contact or support, thus preventing the formation of a solidified shell. Furthermore, the molten metal entering the mold maintains a relatively high temperature. Attached Figure Description

[0041] Figure 1 A diagram of a tilting casting device for suspension melting in existing technology;

[0042] Figure 2 This is a diagram of a bottom casting device for suspension melting in the prior art;

[0043] Figure 3 This is a diagram of the suspension melting apparatus with a combined cold crucible according to the present invention;

[0044] Figure 4 This is a structural diagram of the combined crucible of the present invention;

[0045] Figure 5 This is a structural diagram of a cold crucible without a water jacket;

[0046] Figure 6 A diagram of a gear-rack drive device driven by an electric motor;

[0047] Figure 7 This is a structural diagram of a coaxial water-cooled electrode and an electrode conduit.

[0048] Figure 8 This is a process diagram illustrating the separation and casting of the half-crucible in this invention.

[0049] Reference numerals: 1-Cold crucible, 2-Vacuum chamber, 3-Molten metal, 4-Induction coil, 5-Coaxial electrode, 10-Mold device, 13-Crucible moving device, 14-Electrode moving device, 15-Furnace body, 16-Furnace top, 17-Furnace bottom, 18-Crucible drive rod guide tube, 19-Dynamic sealing device, 20-Coolant interface, 21-Electrode guide tube, 22-Insulating liner, 23-Crucible body, 24-Cooling tube, 25-Water jacket, 26-Cooling main pipe, 27-Vacuum hose, 28-Insulating sleeve, 29-Clamp, 30- - Crucible push rod, 31- Material, 32- Flap, 33- Cooling hole, 34- Coolant supply ring, 35- Coolant return ring, 36- Main supply pipe, 37- Main return pipe, 38- Half crucible, 39- Annular flange, 40- Drive rod, 41- Motor, 42- Gear, 43- Rack, 45- Inner electrode tube, 46- Outer electrode tube, 47- Sealing component, 48- Cable interface, 49- Flexible cable, 50- Electrode water interface pipe, 51- Induction coil interface pipe, 52- Mold, 53- Pouring cup, 54- Sprue. Detailed Implementation

[0050] Combined with appendix Figure 3 As shown, this embodiment provides a suspension melting device with a combined cold crucible, including a melting furnace, an induction power supply, a vacuum-inert gas system, a water cooling system and a control system. The melting furnace includes a vacuum chamber 2, a cold crucible 1, an induction coil 4, a coaxial electrode 5 and a mold device 10.

[0051] Understandably, the cold crucible 1 is installed inside the vacuum chamber 2. After the vacuum-inert gas system evacuates the vacuum chamber 2, the high-frequency current generated by the induction power supply is input to the induction coil 4 surrounding the cold crucible 1. The resulting high-frequency electromagnetic field heats and melts the material in the cold crucible 1. A coaxial electrode 5 extends from the outside of the vacuum chamber 2 into the inside. The portion outside the electrode is connected to the two electrodes of the induction power supply via a cable, while the portion inside the electrode is connected to the two electrodes of the induction coil 4, thus providing power to the induction coil 4. The molten metal in the cold crucible 1 is transferred into the mold device 10 to complete the casting. A water-cooling system supplies cooling water to the cold crucible 1, induction coil 4, vacuum chamber 2, vacuum-inert gas system, and induction power supply to protect these devices. After evacuating the vacuum chamber 2, the vacuum-inert gas system can fill the vacuum chamber 2 with a protective gas, such as argon. The control system can be equipped with a PLC module for automatic control of the equipment operation.

[0052] In this embodiment, the vacuum chamber 2 comprises a furnace body 15, a furnace top 16, and a furnace bottom 17. Specifically, the furnace top 16 is located at the top of the furnace body 15, and the furnace bottom 17 is located at the bottom of the furnace body 15; the three together enclose the vacuum chamber 2. Horizontally oriented crucible drive rod guides 18 are installed on both side walls of the furnace body 15, with the axes of the two crucible drive rod guides 18 coinciding. A dynamic sealing device 19 is provided in each crucible drive rod guide 18. Preferably, the axis of the crucible drive rod guide 18 passes through the center of the vacuum chamber 2.

[0053] Combined with appendix Figure 3-4 To enable the electromagnetic field to penetrate the crucible wall and heat the material 31 in the cold crucible 1, the cold crucible 1 is composed of several lobes 32 whose length direction is parallel to the axis of the cold crucible 1. These lobes 32 form a whole around the cold crucible 1, creating a container for holding the material 31 in the center. The lobes 32 are made of metal, most commonly copper, but stainless steel or other metals can also be used. To enable the cold crucible 1 to withstand high temperatures, each lobe 32 is provided with a cooling hole 33 that communicates with the coolant interface 20.

[0054] Understandably, in the traditional structure of the tilting casting device for suspension melting, one end of the crucible drive rod in the crucible drive rod conduit 18 is connected to the cold crucible 1, and the other end is connected to the rotation drive device. The cold crucible 1 needs to be tilted under the action of the crucible drive rod in order to pour the molten metal into the casting mold 10, which leads to many of the disadvantages described in the background art.

[0055] like Figure 3-4 As shown, to eliminate the negative impact of the tilting casting device in suspension melting, this embodiment proposes a crucible separation casting method. The cold crucible 1 is a combined structure with opening and closing capabilities. The crucible driving rod in the crucible driving rod guide 18 is a crucible pushing rod 30. One end of the crucible pushing rod 30 is connected to the cold crucible 1, and the other end is connected to the crucible moving device 13. At the same time, the coaxial electrode 5 can move vertically under the drive of the electrode moving device 14.

[0056] Thus, during casting, the induction coil 4 moves upward under the action of the electrode moving device 14, so that its lower edge is higher than the upper edge of the cold crucible 1, so that the combined cold crucible 1 obtains the space required for lateral separation; then the combined cold crucible 1 is rapidly separated under the action of the crucible pushing rod 30, and the molten metal falls rapidly into the mold 10 without contact or support, so no solidified shell is formed, and the molten metal entering the mold 10 also maintains a high temperature.

[0057] Specifically, the cold crucible 1 is composed of two symmetrical half crucibles 38. Correspondingly, each half crucible 38 is composed of several lobes 32 whose length direction is parallel to the axis of the cold crucible 1. The several lobes 32 form the whole half crucible 38.

[0058] As one implementation method, see Appendix Figure 3-4 This embodiment is applicable to large-sized cold crucibles 1. The cold crucible 1 includes a half-crucible body 23, cooling tubes 24, a water jacket 25, a main cooling pipe 26, and a vacuum hose 27. The cooling holes 33 of each lobe 32 are connected to the water jacket 25 via the cooling tubes 24. The water jacket 25 is connected to the main cooling pipe 26. The main cooling pipe 26 is connected to a coolant inlet 20 installed on the furnace body 15 via the vacuum hose 27. The coolant inlet 20 is connected to a cooling system outside the vacuum chamber 2.

[0059] Specifically, the water jacket 25 includes an upper coolant supply ring 34 and a lower coolant return ring 35. The coolant supply ring 34 is connected to a main supply pipe 36, and the coolant return ring 35 is connected to a main return pipe 37. Both the main supply pipe 36 and the main return pipe 37 are connected to the coolant inlet 20 installed on the furnace body 15 via a vacuum hose 27.

[0060] Furthermore, such as Figure 3-4 As shown, clamps 29 are fixedly installed on the side of the water jacket 25 of each half crucible 38, and a horizontally oriented crucible push rod 30 is installed on the outside of each clamp 29. The crucible push rod 30 extends away from the half crucible 38, passes through the crucible drive rod guide tube 18 installed in the furnace body 15, extends through the dynamic sealing device 19 in the tube to the outside of the vacuum chamber 2, and is connected to the crucible moving device 13.

[0061] Understandably, the crucible drive rod guide 18 provides support, positioning, and guidance for the crucible push rod 30. The crucible push rod 30 and clamp 29 act as supports, positioning, and pushers for the half-crucibles 38. When the two crucible push rods 30 located on both sides of the furnace body 15 move left and right along the crucible drive rod guide 18, they push the two half-crucibles 38 to merge or separate. Preferably, the clamp 29 is made of insulating materials, such as epoxy resin, polytetrafluoroethylene, bakelite, nylon, etc., but it can also be made of metal materials, such as copper, brass, stainless steel, etc.

[0062] As another implementation method, see Appendix Figure 5 This embodiment is applicable to small-sized cold crucibles 1. The cold crucible 1 is not equipped with cooling tubes 24 and water jackets 25. The cooling holes of each lobe of the half crucible body 23 are connected end to end and connected to the coolant interface 20 of the furnace body 15 through the cooling main pipe 26 and the vacuum hose 27.

[0063] Furthermore, for the small-sized cold crucible 1, since there is no water jacket 25, the clamp 29 under the half crucible 38 is directly installed on the lower edge of the half crucible 38.

[0064] It is worth noting that in the suspension melting equipment with a combined cold crucible in this embodiment, the cold crucible 1 does not need to be flipped. Therefore, the water jacket 25, the cooling main pipe 26, and the vacuum hose 27 also do not need to be flipped, which greatly simplifies the structure.

[0065] In this embodiment, the crucible moving device 13 moves the half-crucible 38 by pushing and pulling. It is installed on both sides outside the vacuum chamber 2, with one set installed on each side, driving the half-crucible 38 on the corresponding side. The crucible moving device 13 can be driven by pneumatic, hydraulic or electric motor. The drive rod 40 of the crucible moving device 13 is arranged in the horizontal direction and is connected to the crucible push rod 30.

[0066] Specifically, when pneumatic or hydraulic drive is used, the connection between the drive rod 40 and the piston rod of the cylinder or oil cylinder is described in [reference needed]. Figure 3 When driven by an electric motor, the motor drives the drive rod 40 through a lead screw-nut structure, a worm gear structure, or a gear-rack structure. Figure 6 The diagram illustrates a gear-rack drive system driven by a motor. Specifically, the crucible moving device 13 includes a motor 41, a gear 42, a rack 43, a drive rod 40, and a controller (not shown). The motor can be an AC motor with speed controlled by a frequency converter, or it can be a stepper motor or a servo motor.

[0067] It is understood that, regardless of the driving method used, the moving speed, position, and limit of the drive rod 40 are all controlled by the controller. Any crucible moving device 13 that can drive the crucible push rod 30 to move horizontally, and whose moving speed, position, and limit are all controllable, falls within the scope of this embodiment.

[0068] It should be noted that the induction coil 4 is a spiral copper tube surrounding the cold crucible 1, through which a coolant is passed to prevent the induction coil 4 itself from being burned by the electromagnetic field.

[0069] In this embodiment, see Figure 3 and Figure 7 An electrode guide tube 21 is installed vertically at the furnace top 16 or furnace bottom 17, and an insulating liner 22 and a dynamic sealing device 19 are installed in the electrode guide tube 21. Preferably, the insulating liner 22 is made of insulating material, such as epoxy resin, polytetrafluoroethylene, bakelite, nylon, etc.

[0070] The coaxial electrode 5 includes an inner electrode tube 45 and an outer electrode tube 46, both of which are filled with cooling water. A sealing element 47 is provided between the inner electrode tube 45 and the outer electrode tube 46 to achieve insulation and prevent cooling water leakage. The coaxial electrode 5 can extend downward into the vacuum chamber 2 from above or upward from below. The coaxial electrode 5 is installed in the electrode conduit 21 of the furnace top 16 or the furnace bottom 17, passing through the insulating lining 22 and the dynamic sealing device 19 in the electrode conduit 21, thus allowing the coaxial electrode 5 to move vertically.

[0071] Outside the vacuum chamber 2, both the inner electrode tube 45 and the outer electrode tube 46 are connected to the two electrodes of the induction power supply via a flexible cable 49 through a cable interface 48. Cooling water is introduced into the coaxial electrode 5 through an electrode water interface pipe 50. Inside the vacuum chamber 2, the inner electrode tube 45 and the outer electrode tube 46 are connected to the two electrodes of the induction coil 4 through an induction coil interface pipe 51. Preferably, both the inner electrode tube 45 and the outer electrode tube 46 are made of copper.

[0072] In this embodiment, the melting furnace further includes an electrode moving device 14 for driving the coaxial electrode 5 to move up and down. The drive rod 40 of the electrode moving device 14 is connected to the portion of the coaxial electrode 5 outside the vacuum chamber 2. Preferably, the electrode moving device 14 can adopt the same structure as the crucible moving device 13.

[0073] like Figure 3 As shown, in this embodiment, to ensure a tight connection between the two half-crucibles 38, an insulating sleeve 28 is fitted onto the outer circumference of the cold crucible 1, with its inner diameter matching the outer diameter of the cold crucible 1. The insulating sleeve 28 fits the two half-crucibles 38 together to form a single cold crucible 1. An annular flange 39 is provided at the upper edge of the insulating sleeve 28, and the annular flange 39 engages with the upper edge of the induction coil 4. Thus, the insulating sleeve 28 not only enhances the connection strength between the two half-crucibles 38 but also provides electromagnetic insulation between the induction coil 4 and the cold crucible 1. Preferably, the insulating sleeve 28 is made of an insulating material, such as epoxy resin, polytetrafluoroethylene, bakelite, or nylon.

[0074] like Figure 3As shown, in this embodiment, the mold device 10 is located directly below the cold crucible 1, and it is an instrument for injecting molten metal to form an ingot or casting. Preferably, the mold device 10 includes a mold 52, a pouring cup 53, and a sprue 54, wherein the diameter of the upper opening of the pouring cup 53 is larger than the inner diameter of the cold crucible 1. In many cases, the mold device 10 may not have a sprue 54, or may not have a sprue 54 and a pouring cup 53. Obviously, if the pouring cup 53 and the sprue 54 are not provided, the diameter of the upper opening of the mold 52 should be larger than the inner diameter of the cold crucible 1. The mold 52 can be made of metal, ceramic, or a ceramic mold shell.

[0075] Based on the suspension melting equipment with a combined cold crucible in this embodiment, a crucible separation casting method is provided. Please refer to the following for details. Figure 3 and Figure 8 The method includes the following steps:

[0076] S1. Before the smelting operation begins, the two half crucibles 38 are pushed together by the crucible moving device 13 to form a whole cold crucible. The induction coil 4 is moved to the position of the cold crucible 1 by the electrode moving device 14. The insulating sleeve 28 is put on the outside of the cold crucible 1 and inserted between the cold crucible 1 and the induction coil 4.

[0077] S2. After vacuuming and filling with inert gas, the induction power supply is started to send high-frequency current to the induction coil 4, and the material 31 in the cold crucible 1 is heated and melted under the action of the electromagnetic field.

[0078] S3. After the melting requirements are met, the electrode moving device 14 is activated, so that the induction coil 4 and the insulating sleeve 28 are rapidly raised until the lower edge of the induction coil 4 and the insulating sleeve 28 are higher than the upper edge of the cold crucible 1, so that the two half crucibles 38 are freed from the restraint of the insulating sleeve 28.

[0079] S4. Immediately start the crucible moving device 13 to quickly separate the two half crucibles 38, so that the molten metal 3 in the crucibles flows downward into the mold device 10 to complete the casting action.

[0080] In S3 and S4 above, to ensure that the molten metal in the crucible falls into the mold completely in a liquid state, the above processes must be completed at an extremely high speed. On the one hand, the lifting speed of the induction coil 4 must be fast, that is, the lifting process of the induction coil 4 must be completed within 30 seconds, preferably within 3 seconds. On the other hand, the separation process of the two half-crucibles 38 must begin within 3 seconds after the end of the lifting process of the induction coil 4 and be completed within 10 seconds, preferably within 1 second after the end of the lifting process of the induction coil 4 and be completed within 1 second.

[0081] Understandably, the control of the driving process of lifting the induction coil 4 and separating the half crucible 38 can be achieved by manually issuing commands to the control system, or by programming the actions of the two driving devices and inputting them into the PLC module for program control.

[0082] This invention provides some specific embodiments to better understand the invention:

[0083] Example 1: A 1kg-class suspension melting device was used, with a vacuum chamber diameter of 500mm. A combined water-cooled copper crucible 1 was installed in the vacuum chamber. The crucible consisted of seven parts: a crucible body 23, cooling tubes 24, a water jacket 25, a main cooling pipe 26, a vacuum hose 27, an insulating sleeve 28, a crucible clamp 29, and a crucible push rod 30. The crucible body had an inner diameter of 50mm, an outer diameter of 70mm, and a height of 100mm. The crucible body was composed of 16 lobes 32 parallel to the crucible axis along its length, each lobe containing a cooling hole 33. Eight lobes formed a group, enclosing a semi-crucible 38 with a semi-circular inner hole in its cross-section. Eight cooling tubes below the semi-crucible lobes connected to the lower semi-circular water jacket. The water jacket had one main water supply pipe 36 and one main water return pipe 37, which were connected to the furnace cooling water interface 20 via the vacuum hose 27.

[0084] Two half-crucibles are joined together to form a circular crucible. An epoxy resin insulating sleeve 28, with an inner diameter of 70.2 mm, an outer diameter of 90 mm, and a height of 120 mm, is fitted over the crucible. This sleeve holds the two half-crucibles together. The upper edge of the insulating sleeve has a 120 mm diameter ring 39, which is used to hang the induction coil 4. Stainless steel clamps 29 are fitted to the side of the water jacket of each half-crucible, and each clamp is fitted with a horizontally extending push rod 30. The push rod passes through a push rod guide 18 in the furnace body, passes through a vacuum seal 19, and extends out of the vacuum chamber 2.

[0085] On each side of the vacuum chamber, there is a cylinder installed in a horizontal direction. The piston rod of the cylinder is connected to the part of the push rod 30 of the half crucible that extends out of the furnace body.

[0086] A spiral-shaped copper induction coil 4 surrounds the crucible 1, with an inner diameter of 92 mm and a height of 120 mm. The induction coil is combined with a coaxial electrode 5 extending into the vacuum chamber from above. The coaxial electrode is connected to the induction power supply via a flexible cable. The coaxial electrode consists of two layers of copper electrode tubes, an inner layer and an outer layer, each containing cooling water. An insulation and leak-proof structure 47 separates the two layers. The coaxial electrode passes through the furnace top 16 of the vacuum chamber 1 via an electrode conduit 21.

[0087] A vertically mounted cylinder is installed on top of the vacuum chamber. The piston rod of the cylinder is connected to a stainless steel rod that serves as a drive rod 40, which is then connected to a coaxial electrode 5.

[0088] The mold device 10 is located below the crucible. It consists of a carbon steel mold 49 and a carbon steel pouring cup 50, with the upper opening of the pouring cup having a diameter of 70 mm.

[0089] Two cylinders on either side of the vacuum chamber push the two half-crucibles inside, bringing them together to form a single crucible. An insulating sleeve is inserted downwards from above the induction coil to cover the crucible. 800g of metallic V is added to the crucible, then the vacuum chamber is evacuated and filled with inert gas. The induction power supply is then activated to heat the V material. Once the metallic V is completely melted, the casting process begins: a coaxial electrode drives the induction coil to rise 150mm in 0.2 seconds. Timing starts from the moment the electrode is raised, and at 0.2 seconds, the cylinder that moves the crucible is activated, separating the two half-crucibles by 80mm within 0.2 seconds. At this point, the molten V in the crucible immediately flows from the pouring cup into the mold. The V ingot in the mold weighs 790g, and the solidified shell adhering to the pouring cup weighs 10g.

[0090] Example 2: The equipment used is the same as in Example 1, except for the water-cooled copper crucible.

[0091] Crucible 1 is a water-cooled copper crucible with an inner diameter of 30 mm, without a water jacket. The outer diameter of the crucible body is 50 mm, the height is 60 mm, and it is divided into 12 segments. The crucible segments are grouped into sets of 6, forming a semi-crucible with a semi-circular inner hole in cross-section. Cooling holes 33 are prepared in each segment of the crucible, and the cooling holes are connected end to end. The first hole is connected to the main water supply pipe 36, and the sixth hole is connected to the main water return pipe 37. The main water supply pipe and the main water return pipe are connected to the cooling water interface 20 of the furnace body through a vacuum hose 27.

[0092] Each half crucible is fitted with a clamp 29 at its lower edge, and each clamp is fitted with a horizontally outward-facing push rod 30. The push rod passes through the push rod guide tube 18 of the furnace body and extends out of the vacuum chamber through a vacuum seal.

[0093] The epoxy resin insulating sleeve 28, which is fitted over the crucible, has an inner diameter of 50.2 mm, an outer diameter of 60 mm, and a height of 65 mm. Its upper edge has a ring 39 with an outer diameter of 90 mm. The induction coil 4, which surrounds the crucible, has an inner diameter of 70 mm, an outer diameter of 90 mm, and a height of 60 mm.

[0094] In this embodiment, no pouring cup is installed on the top of the mold 49, and the diameter of the top opening of the mold is 40mm.

[0095] The smelting process of the equipment is similar to that of Example 1, except that the material added to the crucible is 150g of metallic Ni. The casting process is similar to that of Example 1, except that the induction coil is raised to a height of 80mm and the distance between the half-crucible and the half-crucible is separated is 50mm. After casting, the weight of the Ni ingot obtained from the mold is 149g.

[0096] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A suspension melting device with a combined cold crucible, characterized in that, It includes a melting furnace, an induction power supply, a vacuum-inert gas system, a water cooling system and a control system. The melting furnace includes a vacuum chamber (2), a cold crucible (1), an induction coil (4), a coaxial electrode (5) and a mold device (10). The cold crucible (1), the induction coil (4) and the mold device (10) are installed in the vacuum chamber (2), and the induction coil (4) surrounds the outer periphery of the cold crucible (1). The mold device (10) is used to receive the molten metal in the cold crucible (1). The coaxial electrode (5) extends from the outside of the vacuum chamber (2) into the chamber, with the part outside the chamber combined with the two electrodes of the induction power supply and the part inside the chamber combined with the two electrodes of the induction coil (4). The two side walls of the vacuum chamber (2) are respectively equipped with crucible drive rod guide tubes (18) in a horizontal direction, and each crucible drive rod guide tube (18) is provided with a dynamic sealing device (19). The cold crucible (1) consists of two symmetrical half crucibles (38). A crucible push rod (30) is installed inside the crucible drive rod guide tube (18). One end of the crucible push rod (30) is connected to the half crucible (38), and the other end is connected to the crucible moving device (13). The outdoor portion of the coaxial electrode (5) is also connected to the electrode moving device (14) so ​​that the coaxial electrode (5) moves vertically under the drive of the electrode moving device (14); The mold device (10) is located directly below the cold crucible (1); The crucible moving device (13) is configured such that after the induction coil (4) is raised to a position where its lower edge is higher than the upper edge of the cold crucible (1), it starts to drive the two half crucibles (38) to separate within 3 seconds and completes the separation within 10 seconds, so that the molten metal (3) in the cold crucible (1) flows directly downward into the mold device (10) while remaining in a liquid state.

2. The suspension melting equipment according to claim 1, characterized in that, The half crucible (38) is composed of several lobes (32) whose length direction is parallel to the axis of the cold crucible (1), and the several lobes (32) form the whole half crucible (38); Each of the lobes (32) is provided with a cooling hole (33) that communicates with the coolant interface (20).

3. The suspension melting equipment according to claim 2, characterized in that, The cold crucible (1) includes a half crucible body (23), a cooling tube (24), a water jacket (25), a cooling main pipe (26), and a vacuum hose (27). The cooling holes (33) of each petal (32) are connected to the water jacket (25) through the cooling tube (24). The water jacket (25) is connected to the cooling main pipe (26). The cooling main pipe (26) is connected to the coolant interface (20) installed on the side wall of the vacuum chamber (2) through the vacuum hose (27). The coolant interface (20) is connected to the cooling system outside the vacuum chamber (2).

4. The suspension melting equipment according to claim 3, characterized in that, A clamp (29) is fixedly installed on the side of the water jacket (25) of each half crucible (38). A horizontally oriented crucible push rod (30) is installed on the outside of each clamp (29). The crucible push rod (30) extends away from the half crucible (38), passes through the crucible drive rod conduit (18) installed on the side wall of the vacuum chamber (2), extends through the dynamic sealing device (19) in the tube to the outside of the vacuum chamber (2), and is connected to the crucible moving device (13).

5. The suspension melting equipment according to claim 2, characterized in that, The cold crucible (1) includes a half crucible body (23), a cooling manifold (26), and a vacuum hose (27). The cooling holes (33) of each petal (32) of the semi-crucible body (23) are connected end to end and connected to the coolant interface (20) on the side wall of the vacuum chamber (2) through the cooling main pipe (26) and the vacuum hose (27).

6. The suspension melting equipment according to claim 5, characterized in that, A clamp (29) is fixedly installed on the lower edge side of each half crucible (38). A horizontally oriented crucible push rod (30) is installed on the outside of each clamp (29). The crucible push rod (30) extends away from the half crucible (38), passes through the crucible drive rod conduit (18) installed on the side wall of the vacuum chamber (2), extends through the dynamic sealing device (19) in the tube to the outside of the vacuum chamber (2), and is connected to the crucible moving device (13).

7. The suspension melting equipment according to claim 1, characterized in that, An electrode guide tube (21) is installed vertically on the furnace top (16) or furnace bottom (17), and an insulating liner (22) and a dynamic sealing device (19) are installed in the electrode guide tube (21). The coaxial electrode (5) is installed in the electrode conduit (21) of the furnace top (16) or furnace bottom (17) of the smelting furnace, and passes through the insulating lining (22) and dynamic sealing device (19) in the electrode conduit (21) to penetrate the furnace top (16) or furnace bottom (17).

8. The suspension melting equipment according to claim 7, characterized in that, The coaxial electrode (5) includes an inner electrode tube (45) and an outer electrode tube (46), and both electrode tubes are filled with cooling water. A sealing component (47) is provided between the inner electrode tube (45) and the outer electrode tube (46). Outside the vacuum chamber (2), the inner electrode tube (45) and the outer electrode tube (46) are connected to the two electrodes of the induction power supply through the cable interface (48) via the flexible cable (49), and the cooling water is introduced into the coaxial electrode (5) through the electrode water interface pipe (50). Inside the vacuum chamber (2), the inner electrode tube (45) and the outer electrode tube (46) are connected to the two electrodes of the induction coil (4) through the induction coil interface tube (51).

9. The suspension melting equipment according to claim 1, characterized in that, An insulating sleeve (28) is fitted on the outer circumference of the cold crucible (1), and its inner diameter matches the outer diameter of the cold crucible (1). An annular flange (39) is provided on the upper edge of the insulating sleeve (28), and the annular flange (39) is combined with the upper edge of the induction coil (4).

10. A crucible separation casting method, using the suspension melting equipment as described in claim 9, characterized in that, Includes the following steps: S1. Before the smelting work begins, use the crucible moving device (13) to push the two half crucibles (38) together to form a whole cold crucible. Use the electrode moving device (14) to move the induction coil (4) to the position of the cold crucible (1). Put the insulating sleeve (28) on the outside of the cold crucible (1) and insert it between the cold crucible (1) and the induction coil (4). S2. After vacuuming and filling with inert gas, the induction power supply is started to supply high-frequency current to the induction coil (4), and the material (31) in the cold crucible (1) is heated and melted under the action of the electromagnetic field. S3. After the melting requirements are met, start the electrode moving device (14) to make the induction coil (4) and the insulating sleeve (28) rise rapidly until the lower edge of the induction coil (4) and the insulating sleeve (28) is higher than the upper edge of the cold crucible (1), so that the two half crucibles (38) are freed from the constraint of the insulating sleeve (28). The lifting process of the induction coil (4) is completed within 30 seconds; S4. Immediately start the crucible moving device (13) to quickly separate the two half crucibles (38) so that the molten metal (3) in the crucible flows downward into the mold device (10) to complete the casting action; The separation process of the two half crucibles (38) must begin within 3 seconds after the lifting process of the induction coil (4) ends and be completed within 10 seconds.

11. The crucible separation casting method according to claim 10, characterized in that, The lifting process of the induction coil (4) in step S3 is completed within 3 seconds; the separation process of the two half crucibles (38) in step S4 is to start within 1 second after the lifting process of the induction coil (4) is completed within 1 second.

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