Hollow electrode synchronous pressing device and method for vacuum consumable arc furnace

Abstract

The present application belongs to the technical field of electrode preparation, and discloses a hollow electrode synchronous pressing device and method for a vacuum consumable arc furnace. The pressing device comprises a synchronous pressing unit and a linkage demolding unit. The synchronous pressing unit comprises a hollow punch assembly and a lower die assembly. The hollow punch assembly comprises a fixed plate and a plurality of hollow cylindrical punches, and the hollow cylindrical punches are connected with a driving device through the fixed plate. The lower die assembly is internally provided with a cylindrical die cavity corresponding to the hollow cylindrical punches, and the hollow cylindrical punches can move up and down relative to the lower die assembly. The linkage demolding unit comprises an independently liftable process core rod assembly and a bottom die assembly. The bottom die assembly can move up and down relative to the lower die assembly, and the process core rod assembly cooperates with the hollow cylindrical punches to press the raw material in the cylindrical die cavity into a hollow electrode. The present application realizes the batch production, high efficiency and low loss of the hollow electrode, and is particularly suitable for large-scale preparation of alloy smelting electrodes.

Description

Technical Field

[0001] This invention belongs to the field of vacuum consumable arc furnace electrode preparation technology, specifically relating to a device and method for synchronous pressing of hollow electrodes for a vacuum consumable arc furnace. Background Technology

[0002] Vacuum consumable arc furnaces are core equipment for producing titanium and titanium alloy ingots. The required consumable electrodes are typically made by pressing sponge titanium and alloying additives. For NbTi alloys, NbTi composite electrodes need to be prepared to obtain ingots with uniform composition. Existing methods for preparing composite electrodes mainly include the following: Ingot perforation method: First, a sponge titanium electrode is pressed, then melted into an ingot using a vacuum consumable arc furnace. After perforation, a niobium rod is inserted. This method results in significant material waste and high processing costs.

[0003] Tile-type split pressing and welding method: Tile-type electrode blocks and niobium rods are prepared separately and then assembled and welded. The process is complicated, the dimensional accuracy required for tile splicing is high, the equipment requirements are extremely high, and there are many weld seams, which may become sources of contamination or weak points. The welding quality directly affects the stability of smelting.

[0004] Titanium plate wrapping method: Titanium plates are welded into round tubes, and niobium rods are inserted as core rods to form composite electrodes. This method has a long plate processing flow, high losses, and extremely high costs.

[0005] Existing pressing molds are mostly single-cavity designs or semi-circular pressing molds, and there is a lack of hollow electrode molds required for NbTi alloys. Traditional methods suffer from low production efficiency and high costs. Therefore, there is an urgent need for a new scheme for the preparation of NbTi hollow electrodes that can achieve high efficiency, low cost, high quality, and is suitable for large-scale production. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a synchronous pressing device and method for hollow electrodes in a vacuum consumable arc furnace. The pressing device of this invention integrates high-efficiency pressing, reliable demolding, and assembly, enabling batch synchronous pressing of hollow electrode blocks, significantly improving equipment utilization and production efficiency. It employs low-cost, reusable process mandrels to solve the demolding problem in hollow body pressing, thereby extending the device's service life.

[0007] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows: In a first aspect, embodiments of the present invention provide a synchronous pressing device for hollow electrodes in a vacuum consumable arc furnace, comprising a synchronous pressing unit and a linkage demolding unit; The synchronous pressing unit includes a hollow punch assembly and a lower die assembly. The hollow punch assembly includes a fixed plate and a plurality of hollow cylindrical punches. One end of each hollow cylindrical punch is connected to the fixed plate, which is used to connect to a driving device. The lower die assembly has a cylindrical die cavity inside, and each cylindrical die cavity corresponds to one of the hollow cylindrical punches. The central axis of each hollow cylindrical punch coincides with the central axis of the cylindrical die cavity, and the hollow cylindrical punches can move up and down relative to the lower die assembly. The linkage demolding unit includes an independently liftable process mandrel assembly and a bottom mold assembly. The bottom mold assembly can move up and down relative to the lower mold assembly, and the process mandrel assembly can move up and down relative to the bottom mold assembly. The top of the process mandrel assembly can pass through the bottom mold assembly and enter the cylindrical mold cavity, and cooperate with the hollow cylindrical punch to press the raw material in the cylindrical mold cavity into a hollow electrode.

[0008] Furthermore, the other end of the hollow cylindrical punch is provided with a downward protrusion; The upper surface of the bottom mold assembly is provided with a groove, which is adapted to the lower protrusion, and the two can be spliced ​​and fixed.

[0009] Furthermore, the bottom mold assembly includes a main body and a protrusion, the protrusion being disposed on the upper surface of the main body, and the groove being disposed on the upper surface of the protrusion.

[0010] Furthermore, the outer diameter D2 of the protrusion is less than or equal to the diameter D of the cylindrical mold cavity, and the protrusion is at least partially accommodated in the cylindrical mold cavity and is snapped and fixed to the lower end of the cylindrical mold cavity.

[0011] Furthermore, the diameter of the cylindrical mold cavity is adapted to the outer diameter of the hollow cylindrical punch, so that the hollow cylindrical punch can move up and down in the cylindrical mold cavity.

[0012] Furthermore, the process mandrel assembly includes a mandrel body and a base, the base being located at the bottom end of the mandrel body, the top end of the mandrel body being hemispherical, and the base being used to connect an independent lifting hydraulic system.

[0013] Furthermore, the outer diameter D1 of the mandrel body is less than the size of the base, the mandrel body can pass through the bottom mold assembly and enter the cylindrical mold cavity, and the base is locked on the lower surface of the bottom mold assembly.

[0014] Furthermore, the outer diameter D1 of the mandrel body is less than the inner diameter d1 of the hollow cylindrical punch, which is less than the diameter D of the cylindrical die cavity, and the height H of the cylindrical die cavity is greater than the maximum rising height of the process mandrel assembly.

[0015] Furthermore, a positioning groove is provided on the side of the fixing plate, which is used to position the fixing plate.

[0016] In a second aspect, embodiments of the present invention provide a method for synchronously pressing hollow electrodes for a vacuum consumable arc furnace, applied to the synchronous pressing device for hollow electrodes for a vacuum consumable arc furnace described in the first aspect, comprising the following steps: Step S1, Initialization and Fabrication: Calculate the required cavity height for fabrication, control all process mandrel assemblies to rise to the fabrication position, at which point the top of the process mandrel assembly is above the required cavity height, and quantitatively feed raw materials into each cylindrical cavity. Step S2, Synchronous Pressing: The driving device drives the hollow punch assembly to move down synchronously to compact the raw material. After reaching the set pressure, the pressure is maintained to form a hollow electrode surrounding the mandrel body. Subsequently, the driving device drives the hollow cylindrical punch to reset. Preferably, the pressure is set to 500-700 MPa; Step S3, Secondary Linkage Demolding: The process mandrel assembly descends synchronously a certain distance until the top of the process mandrel assembly is completely detached from the inner hole of the hollow electrode; the bottom mold assembly descends so that the hollow electrode is detached from the bottom mold assembly; the bottom mold assembly and the process mandrel assembly rise and reset to the fabrication position, ready to prepare for the preparation of the next set of electrode blocks.

[0017] Compared with the prior art, the present invention has the following significant advantages: (1) The multi-station design of this invention increases the output of a single pressing several times, giving full play to the potential of large-tonnage presses. Multi-station synchronous pressing ensures high consistency of products in the same batch. The hemispherical mandrel head ensures uniform filling of raw materials and smooth inner hole.

[0018] (2) The present invention uses reusable process mandrel components, which has extremely low tooling costs and standardized hollow electrode mass production, reducing mold change and adjustment time.

[0019] (3) The pressing method of the hollow electrode of the present invention is continuous from material laying, pressing, demolding, stacking to welding. Since the Nb rod is in the center, the melting is not easy to "drop eggs", which can be easily automated, reduce manual intervention, and improve production safety and stability.

[0020] (4) The hollow electrode pressing method of the present invention improves the flexibility of production planning and material utilization through the modular production mode of “first making standard titanium electrodes and then installing customized niobium rods”, ensuring uniform electrode blank density and accurate dimensions, and providing high-quality preforms for subsequent smelting. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the hollow electrode synchronous pressing device in Embodiment 1 of the present invention.

[0022] Figure 2 yes Figure 1 A schematic diagram of the punch assembly in the pressing device.

[0023] Figure 3 yes Figure 1 A cross-sectional view of the punch assembly in the pressing device.

[0024] Figure 4 yes Figure 1 A top view of the lower die assembly in the pressing device.

[0025] Figure 5 yes Figure 1 Cross-sectional view of the lower die assembly in the pressing device.

[0026] Figure 6 yes Figure 1 A top view of the bottom mold assembly in the pressing device.

[0027] Figure 7 yes Figure 1 Cross-sectional view of the bottom mold assembly in the pressing device.

[0028] Figure 8 yes Figure 1 A schematic diagram of the process mandrel assembly in the pressing device.

[0029] Figure 9 yes Figure 1 Cross-sectional view of the process mandrel assembly in the pressing device.

[0030] Figure 10 This is a schematic diagram of the hollow electrode obtained in Example 4.

[0031] Figure 11 This is a cross-sectional view of the hollow electrode prepared in Example 4.

[0032] Explanation of reference numerals in the attached drawings: 1-Hollow punch assembly; 2-Lower mold assembly; 11-Hollow cylindrical punch; 12-Fixing plate; 13-Lower protrusion; 14-Positioning groove; 15-Hollow part; 21-Cylindrical mold cavity; 4-Process mandrel assembly; 3-Bottom mold assembly; 30-Main body; 31-Protrusion; 32-Groove; 41-Mandrel body; 42-Base; A-Synchronous pressing unit; B-Linked demolding unit. Detailed Implementation

[0033] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "inner" and "outer", "upper" and "lower", "left" and "right" is usually based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention.

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] Example 1 like Figure 1 As shown, a synchronous pressing device for hollow electrodes in a vacuum consumable arc furnace includes a synchronous pressing unit A and a linkage demolding unit B. The synchronous pressing unit A is located inside the hydraulic press main unit and includes a hollow punch assembly 1 and a lower die assembly 2.

[0036] In one implementation, multiple hollow cylindrical punches 11 can be provided, i.e., two or more. This application embodiment uses four hollow cylindrical punches 11 as an example for illustration.

[0037] like Figure 2 and Figure 3 As shown, the hollow punch assembly 1 includes a fixed plate 12 and four hollow cylindrical punches 11. The upper ends of the hollow cylindrical punches 11 are connected to the fixed plate 12. The fixed plate 12 is connected to the movable crossbeam of the hydraulic press. The side of the fixed plate 12 is provided with a positioning groove 14, which cooperates with a positioning pin to position the fixed plate 12. The lower end of the hollow cylindrical punches 11 is provided with a lower protrusion 13.

[0038] In one embodiment, the lower protrusion 13 is truncated cone-shaped, and the size of the lower protrusion 13 decreases from top to bottom.

[0039] The hollow cylindrical punch 11 has a hollow part 15 inside.

[0040] In one implementation, the four hollow cylindrical punches 11 are arranged in a 2×2 rectangular array.

[0041] like Figure 4 and Figure 5 As shown, the lower mold assembly 2 has four cylindrical mold cavities 21 inside. Each cylindrical mold cavity 21 is corresponding to each hollow cylindrical punch 11. The central axis of the hollow cylindrical punch 11 coincides with the central axis of the cylindrical mold cavity 21. The hollow cylindrical punch 11 can move up and down relative to the lower mold assembly 2 under the drive of the hydraulic press.

[0042] When it is necessary to add material into the cylindrical mold cavity 21, the hydraulic press drives the hollow cylindrical punch 11 to move upward, so that the hollow cylindrical punch 11 separates from the cylindrical mold cavity 21, making it easier to add material into the cylindrical mold cavity 21.

[0043] The linkage demolding unit B includes an independently liftable process mandrel assembly 4 and a bottom mold assembly 3. The bottom mold assembly 3 can move up and down relative to the lower mold assembly 2, and the process mandrel assembly 4 can move up and down relative to the bottom mold assembly 3. The process mandrel assembly 4 can pass through the bottom mold assembly 3 and enter the cylindrical mold cavity 21, and cooperate with the hollow cylindrical punch 11 to press the raw material in the cylindrical mold cavity 21 into a hollow electrode.

[0044] When the material feeding is completed and it is necessary to press the hollow electrode, the hydraulic press drives the hollow cylindrical punch 11 to move downward, and the bottom mold assembly 3 and the process mandrel assembly 4 both move upward. The mandrel body 41 in the process mandrel assembly 4 can pass through the protrusion 31 of the bottom mold assembly 3 and enter the cylindrical mold cavity 21. It cooperates with the downward moving hollow cylindrical punch 11 to press the raw material in the cylindrical mold cavity 21 into a hollow electrode.

[0045] The diameter of the cylindrical cavity 21 is matched with the outer diameter of the hollow cylindrical punch 11, so that the hollow cylindrical punch 11 can move up and down in the cylindrical cavity 21.

[0046] like Figure 6 and Figure 7 As shown, the bottom mold assembly 3 includes a main body 30 and a protrusion 31. The protrusion 31 is disposed on the upper surface of the main body 30, and the groove 32 is disposed on the upper surface of the protrusion 31.

[0047] The outer diameter D2 of the protrusion 31 is less than or equal to the diameter D of the cylindrical mold cavity 21. The protrusion 31 can be fully accommodated in the cylindrical mold cavity 21 and is fixedly engaged with the lower end of the cylindrical mold cavity 21.

[0048] In one embodiment, the upper end of the protrusion 31 is provided with a frustum-shaped groove 32. The size of the groove 32 decreases from top to bottom. The groove 32 is adapted to the lower protrusion 13, and the two can be spliced ​​together. Since the groove 32 and the lower protrusion 13 correspond to the two ends of the hollow electrode when the hollow electrode is pressed in the cylindrical mold cavity 21 of the lower mold assembly 2, the groove 32 and the lower protrusion 13 are adapted to each other, which can make the multiple hollow electrodes spliced ​​and fixed end to end.

[0049] In addition, the shape of the groove 32 is adapted to the lower end of the cylindrical mold cavity 21. The size of the groove 32 decreases from top to bottom, while the size of the lower end of the cylindrical mold cavity 21 increases from top to bottom. The two are adapted to each other, which can prevent material leakage.

[0050] In one implementation, the thickness of the bottom mold assembly 3 is 300mm.

[0051] like Figure 8 and Figure 9 As shown, the process mandrel assembly 4 includes a mandrel body 41 and a base 42. The base 42 is located at the bottom end of the mandrel body 41, and the top end of the mandrel body 41 is hemispherical. The base 42 is used to connect an independent mandrel lifting hydraulic system.

[0052] The shape of the hollow portion 15 is adapted to the shape of the mandrel body 41, and the hollow cylindrical punch 11 and the process mandrel assembly 4 cooperate to produce a hollow electrode. In one embodiment, both the hollow portion 15 of the hollow cylindrical punch 11 and the mandrel body 41 are cylindrical, and the two can cooperate to produce a cylindrical hollow electrode.

[0053] The outer diameter D1 of the mandrel body 41 is less than the size of the base 42. The mandrel body 41 can pass through the bottom mold assembly 3 and enter the cylindrical mold cavity 21. The base 42 is stuck on the lower surface of the bottom mold assembly 3.

[0054] The outer diameter D1 of the mandrel body 41 is less than the inner diameter d1 of the hollow cylindrical punch 11 and the diameter D of the cylindrical mold cavity 21. Furthermore, the height H of the cylindrical mold cavity 21 is greater than the maximum rising height of the process mandrel assembly 4, thereby ensuring that the process mandrel assembly 4 can always be located inside the cylindrical mold cavity 21.

[0055] In one implementation, the mandrel body 41 has an outer diameter of Φ152mm, a length of 800mm, and a top hemisphere with an R76mm diameter. It is made of H13 mold steel, with a nitrided and polished surface. Each mandrel body 41 has a base 42 at its bottom connected to an 80-ton servo hydraulic cylinder. The four servo hydraulic cylinders are precisely synchronized through a closed-loop servo control system.

[0056] In one embodiment, the hollow cylindrical punch 11 has an outer diameter of Φ279.8mm (with a gap of 0.2mm), an inner diameter of Φ152.2mm, and a length of 800mm; the cylindrical mold cavity 21 has a diameter of Φ280mm.

[0057] Example 2 A hollow electrode synchronous pressing device for a vacuum self-consuming electric arc furnace differs from Embodiment 1 in that the hollow punch assembly 1 includes a fixed plate 12 and a hollow cylindrical punch 11, and the lower die assembly 2 has a cylindrical die cavity 21 inside, which is correspondingly arranged with the hollow cylindrical punch 11.

[0058] Example 3 A synchronous pressing system for hollow electrodes in a vacuum self-consuming electric arc furnace includes the above-mentioned pressing device, a lower worktable and a lifting platform. The lower mold assembly 2 is fixed on the lower worktable, and a heat insulation pad is provided between the bottom of the lower mold assembly 2 and the lower worktable. The bottom mold assembly 3 is fixed on the lifting platform and positioned by guide columns. Driven by the lifting platform, the bottom mold assembly 3 can move up and down relative to the lower mold assembly 2.

[0059] Specifically, the bottom mold assembly 3 is bolted to the lifting platform and positioned by guide columns. The guide columns are fixed on the lower worktable, and the guide sleeve is embedded in the lifting platform to ensure that the bottom mold assembly 3 does not tilt when it is raised or lowered.

[0060] In one implementation, the lower mold assembly 2 is connected to the lower worktable via a T-slot, T-bolts, and a positioning block. The T-bolts are located at the bottom of the lower mold assembly 2, pass through the T-slots, and are secured with nuts. The positioning block fits against the side of the lower worktable. Since T-slots and T-bolts are common structures, their structure is not described here. It is understood that any structure that enables the connection between the lower mold assembly 2 and the lower worktable will meet the requirements.

[0061] In one implementation, the lifting platform of the bottom mold assembly 3 is driven by a 500-ton hydraulic cylinder.

[0062] Example 4 A method for synchronously pressing hollow electrodes for a vacuum consumable arc furnace, applied to the synchronous pressing device for hollow electrodes for a vacuum consumable arc furnace in Example 1, includes the following steps: Step S1, Initialization and Fabrication: Calculate the required mold cavity height for fabrication, and control all process mandrel assemblies 4 to rise to the fabrication position. At this time, the top of the process mandrel assembly 4 is located above the required mold cavity. Quantitatively add 40.6 kg of sponge titanium particles to each cylindrical mold cavity 21. Since the top of the mandrel body 41 is hemispherical, the sponge titanium particles are naturally distributed around the mandrel body 41. Step S2, Synchronous pressing: The hydraulic press (pressure of 12,000 tons) drives the hollow punch assembly 1 to move down synchronously to compact the sponge titanium particles. After reaching the set pressure of 600 MPa, the pressure is held for 12 seconds and then returned to form a titanium hollow electrode surrounding the mandrel body 41. Subsequently, the hydraulic press drives the movable crossbeam to reset the hollow cylindrical punch 11. Step S3, Secondary Linkage Demolding: The process mandrel assembly 4 descends synchronously by 500mm under the drive of an independent hydraulic system until the top of the mandrel body 41 is completely detached from the inner hole of the titanium hollow electrode; the bottom mold assembly 3 and the lifting platform descend as a whole by 300mm, and the titanium hollow electrode falls smoothly into the corresponding transport platform under the action of gravity; the bottom mold assembly 3 and the process mandrel assembly 4 rise and reset to the material placement position, ready to prepare for the preparation of the next set of electrode blocks; Step S4: Repeat steps S1-S3, pressing 6 groups to obtain 24 hollow titanium electrodes, as shown. Figure 10 and Figure 11 As shown, 24 hollow titanium electrodes are placed neatly on a stacking rack. Step S5: Using a niobium-piercing device, insert a 6.24m long pure niobium rod (Φ152mm) into the center hole of the row of titanium hollow electrodes (24×0.26m); hoist the titanium hollow electrodes with the niobium rod inserted to the welding station, and weld the 23 butt joint seams between the titanium hollow electrodes to make a complete consumable electrode to be melted.

[0063] The obtained titanium hollow electrode is an NbTi composite electrode with an outer diameter of Φ280mm, an inner diameter of Φ152mm, a height of 260mm, and a density of 3.6 g / cm³.

[0064] Implementation Results: In this embodiment, the single cycle time is approximately 5 minutes (including material application, pressing, demolding, and resetting), and approximately 50 electrode blocks can be produced per hour, which is 4 times more efficient than a single-cavity mold. The process mandrel has a long lifespan and is removable and replaceable. The prepared composite electrode, after testing, exhibits uniform density (deviation < ±0.05 g / cm³), good niobium rod centering (eccentricity < 1 mm), and high weld joint strength, fully meeting the smelting requirements for high-end NbTi alloy ingots.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A synchronous pressing device for hollow electrodes in a vacuum consumable arc furnace, characterized in that, It includes a synchronous pressing unit (A) and a linked demolding unit (B); The synchronous pressing unit (A) includes a hollow punch assembly (1) and a lower die assembly (2). The hollow punch assembly (1) includes a fixed plate (12) and a plurality of hollow cylindrical punches (11). One end of the hollow cylindrical punch (11) is connected to the fixed plate (12), and the fixed plate (12) is used to connect to the driving device. The lower die assembly (2) has a cylindrical die cavity (21) inside. The cylindrical die cavity (21) corresponds one-to-one with the hollow cylindrical punch (11), and the central axis of the hollow cylindrical punch (11) coincides with the central axis of the cylindrical die cavity (21). The hollow cylindrical punch (11) can move up and down relative to the lower die assembly (2). The linkage demolding unit (B) includes a process mandrel assembly (4) and a bottom mold assembly (3) that can be raised and lowered independently. The bottom mold assembly (3) can move up and down relative to the lower mold assembly (2). The process mandrel assembly (4) can move up and down relative to the bottom mold assembly (3). The top of the process mandrel assembly (4) can pass through the bottom mold assembly (3) and enter the cylindrical mold cavity (21), and cooperate with the hollow cylindrical punch (11) to press the raw material in the cylindrical mold cavity (21) into a hollow electrode.

2. The synchronous pressing device for hollow electrodes in a vacuum consumable arc furnace according to claim 1, characterized in that, The hollow cylindrical punch (11) has a lower protrusion (13) at the other end. The upper surface of the bottom mold assembly (3) is provided with a groove (32), which is adapted to the lower protrusion (13) and the two can be spliced ​​and fixed.

3. The hollow electrode synchronous pressing device for a vacuum consumable arc furnace according to claim 2, characterized in that, The bottom mold assembly (3) includes a main body (30) and a protrusion (31). The protrusion (31) is disposed on the upper surface of the main body (30), and the groove (32) is disposed on the upper surface of the protrusion (31).

4. The hollow electrode synchronous pressing device for a vacuum consumable arc furnace according to claim 3, characterized in that, The outer diameter D2 of the protrusion (31) is less than or equal to the diameter D of the cylindrical mold cavity (21). The protrusion (31) is at least partially accommodated in the cylindrical mold cavity (21) and is snapped and fixed to the lower end of the cylindrical mold cavity (21).

5. The synchronous pressing device for hollow electrodes in a vacuum consumable arc furnace according to any one of claims 1 to 4, characterized in that, The diameter of the cylindrical cavity (21) is adapted to the outer diameter of the hollow cylindrical punch (11), so that the hollow cylindrical punch (11) can move up and down in the cylindrical cavity (21).

6. The hollow electrode synchronous pressing device for a vacuum consumable arc furnace according to any one of claims 1 to 4, characterized in that, The process mandrel assembly (4) includes a mandrel body (41) and a base (42). The base (42) is located at the bottom of the mandrel body (41). The top of the mandrel body (41) is hemispherical. The base (42) is used to connect an independent lifting hydraulic system.

7. The synchronous pressing device for hollow electrodes in a vacuum consumable arc furnace according to claim 6, characterized in that, The outer diameter D1 of the mandrel body (41) is less than the size of the base (42). The mandrel body (41) can pass through the bottom mold assembly (3) and enter the cylindrical mold cavity (21). The base (42) is locked on the lower surface of the bottom mold assembly (3).

8. The synchronous pressing device for hollow electrodes in a vacuum consumable arc furnace according to claim 6, characterized in that, The outer diameter D1 of the mandrel body (41) is less than the inner diameter d1 of the hollow cylindrical punch (11) and the diameter D of the cylindrical mold cavity (21) is less than the diameter D of the cylindrical mold cavity (21), and the height H of the cylindrical mold cavity (21) is greater than the maximum rising height of the process mandrel assembly (4).

9. The synchronous pressing device for hollow electrodes in a vacuum consumable arc furnace according to any one of claims 1 to 8, characterized in that, The side of the fixing plate (12) is provided with a positioning groove (14), which is used to position the fixing plate (12).

10. A method for synchronous pressing of hollow electrodes in a vacuum consumable arc furnace, characterized in that, The device for synchronous pressing of hollow electrodes for a vacuum consumable arc furnace as described in any one of claims 1 to 9 comprises the following steps: Step S1, Initialization and Fabrication: Calculate the required cavity height for fabrication, control all process mandrel assemblies (4) to rise to the fabrication position, at which time the top of the process mandrel assembly (4) is above the required cavity height, and quantitatively feed raw materials into each cylindrical cavity (21); Step S2, Synchronous pressing: The driving device drives the hollow punch assembly (1) to move down synchronously to compact the raw material. After reaching the set pressure, the pressure is maintained to form a hollow electrode surrounding the core rod body (41). Subsequently, the driving device drives the hollow cylindrical punch (11) to reset. Step S3, Secondary linkage demolding: The process mandrel assembly (4) descends synchronously by a certain distance until the top of the process mandrel assembly (4) is completely detached from the inner hole of the hollow electrode; the bottom mold assembly (3) descends so that the hollow electrode is detached from the bottom mold assembly (3); the bottom mold assembly (3) and the process mandrel assembly (4) rise and reset to the fabrication position to prepare for the preparation of the next set of electrode blocks.

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