Vacuum induction melting and casting furnace for producing neodymium-iron-boron magnet

Abstract

The utility model relates to a neodymium iron boron magnet production equipment technical field, and disclose a kind of vacuum induction smelting casting piece furnace for neodymium iron boron magnet production, including the induction heating part located in smelting casting piece furnace inside and the smelting crucible wrapped in induction heating part inside, smelting crucible top is equipped with for the inner wall stripping cleaning part of its inner wall cleaning, inner wall stripping cleaning part includes auxiliary shovel removal part, stripping part, stripping drive part and lifting piece;Auxiliary shovel removal part includes fixed ring and shovel removal board, shovel removal board is symmetrically distributed in the bottom of fixed ring two sides, the outer wall profile of shovel removal board is compatible with the inner wall structure of smelting crucible, and closely combined with inner wall, for the solid alloy adhesion on smelting crucible inner wall is scraped and cleaned.The application two-stage cleaning and full height coverage, residual removal rate is high, to prevent melt pollution, guarantee magnet purity;Automatic cleaning, high efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of neodymium iron boron magnet production equipment, specifically a vacuum induction melting and casting furnace for neodymium iron boron magnet production. Background Technology

[0002] As a high-performance permanent magnet material, neodymium iron boron magnets are widely used in electronics, new energy and other fields. Among them, sintered neodymium iron boron magnets are formed by vacuum high-temperature heating. The melting and casting process is the key link in the production. The core equipment consists of a medium-frequency induction power supply, a vacuum unit, and a vacuum container. Components such as crucibles and tundishes are integrated into the vacuum container.

[0003] During production, NdFeB base materials are added to a crucible in a specific ratio and melted and alloyed at temperatures exceeding 1300°C. Elements such as dysprosium and terbium are added to optimize magnetic properties, and the entire process relies on a vacuum and inert atmosphere to prevent oxidation and maintain purity. The molten metal undergoes processes such as spinning, hydrogen breaking, and air jet milling to ultimately produce magnetic powder.

[0004] However, in actual production, the problem of residues after crucible melting is prominent: due to uneven feeding, heating and furnace temperature, raw materials are prone to not being fully melted, forming solid alloy particles that adhere; even with vacuum / inert protection, fluctuations in vacuum degree and gas purity or slight leakage of the crucible can still cause rare earth elements to react with trace amounts of oxygen and water vapor, generating rare earth oxides that are difficult to clean; at high temperatures, rare earth elements and boron nitride crucibles will also undergo micro-reactions, producing borides and nitrides; impacts during charging, friction during cleaning and thermal fatigue can also cause crucible debris to peel off and remain.

[0005] If these residues are not cleaned, they will directly contaminate the melt for the next smelting, seriously affecting the purity and performance of the magnets. Current manual cleaning methods (cleaning with a shovel while standing on top of the crucible) are limited by the complex structure of the crucible and the distribution of residues, resulting in narrow operating space and significant difficulty in peeling and cleaning; moreover, manual methods are inefficient and time-consuming, making them unsuitable for the large-scale, high-efficiency production pace of the industry. Therefore, we have proposed a vacuum induction melting and casting furnace for NdFeB magnet production to address the aforementioned problems. Utility Model Content

[0006] The purpose of this utility model is to provide a vacuum induction melting and casting furnace for the production of neodymium iron boron magnets, so as to solve the problem mentioned in the background art that after the casting furnace crucible is used, it needs to be cleaned in order to prevent contamination of the subsequent molten magnet material. Currently, manual cleaning of the casting furnace crucible involves standing on the top of the crucible and using a cleaning shovel. However, due to the complex structure of the crucible and the distribution of residues, the operating space is limited, the cleaning is difficult, and the cleaning efficiency is low.

[0007] This utility model provides the following technical solution: A vacuum induction melting and casting furnace for producing neodymium iron boron magnets includes an induction heating element located inside the furnace and a melting crucible enclosing the induction heating element. The top of the melting crucible is provided with an inner wall stripping and cleaning component for cleaning its inner wall. The inner wall stripping and cleaning component includes an auxiliary scraping component, a stripping component, a stripping drive component, and a lifting component. The auxiliary scraping component includes a fixing ring and scraping plates. The scraping plates are symmetrically distributed on both sides of the bottom of the fixing ring. The outer contour of the scraping plates is adapted to the inner wall structure of the melting crucible and fits tightly against the inner wall, used to scrape and clean solid alloy adhering to the inner wall of the melting crucible.

[0008] Preferably, the peeling component includes a fixed shaft, a three-jaw peeling frame, and peeling gears. The top of the three-jaw peeling frame is fixedly connected to the bottom of the fixed shaft. The ends of the three claws of the three-jaw peeling frame are all provided with horizontal mounting grooves. The peeling gears are installed in the horizontal mounting grooves through a rotating shaft, and the three peeling gears are radially distributed, with their rims tangent to the inner wall of the melting crucible.

[0009] Preferably, each of the three claws of the three-claw peeling frame has a limiting screw hole at the top of its outer edge on one side. An adjusting bolt passes through the limiting screw hole, and the bottom of the adjusting bolt extends into the horizontal mounting groove of the claw, abutting against the inner side of the tooth groove of the peeling gear. The adjusting bolt is a detachable structure, and by unscrewing the adjusting bolt, the peeling gear can be rotated to adjust the contact position of its outermost rim.

[0010] Preferably, the stripping drive includes a dust cover, a drive motor, a drive gear, a driven gear, a bearing, and a connecting shaft. The bearing is sleeved on the outer circumferential wall below the connecting shaft. The top of the fixed shaft passes through the dust cover and is fixedly sleeved outside the bearing. The driven gear is sleeved outside the fixed shaft at the top of the dust cover. The drive gear meshes with one side of the driven gear. The output end of the drive motor is connected to the drive gear. The outer circumferential wall above the connecting shaft is connected to the inner wall of the top of the dust cover through a connecting crossbar. The outer wall of the dust cover is connected to the inner wall of the fixing ring.

[0011] Preferably, the lifting component includes a lifting cover plate, the bottom of which is connected to the top of the connecting shaft, and the top of which is connected to an external lifting motor.

[0012] Preferably, the scraping plate has a scraping scraper on the lower inner surface of the side facing the inner wall of the melting crucible. The scraping scraper is made of silicon nitride ceramic material with a thickness of 3mm and the edge of the scraping scraper is set at a 45° acute angle.

[0013] This utility model has the following beneficial effects: 1. This application employs a two-stage cleaning process, involving fine grinding and crushing followed by scraping to remove glass, thereby improving the residue removal rate. The scraping plate is adaptable to the inner wall, and the gears are positionally adjustable, resulting in strong structural adaptability. A dust cover protects the drive components, ensuring component stability. This significantly improves efficiency, avoids the risks of manual operation, standardizes the cleaning effect, and guarantees production safety and stable magnet quality.

[0014] 2. The radial stripping gears of the stripping component scrape away stubborn oxides and borides by rotating. The adjusting bolts can also adjust the gear contact position to avoid excessive local wear caused by long-term fixed contact, thereby achieving wear surface rotation and extending the service life of the stripping gears.

[0015] 3. The peeling drive and lifting components enable automated operation of rotary peeling and lifting covering, eliminating the need for manual climbing; the auxiliary shovel and peeling components work together for high cleaning efficiency. Attached Figure Description

[0016] Figure 1 This is an overall isometric view of the present invention.

[0017] Figure 2 This is a schematic diagram of the inner wall peeling and cleaning component and the melting crucible of this utility model.

[0018] Figure 3 This is a schematic diagram of the disassembled structure of the inner wall peeling and cleaning component of this utility model.

[0019] Figure 4 This is a schematic diagram of the stripping drive component of this utility model.

[0020] Figure 5 This is a schematic diagram of the peeling component structure of this utility model.

[0021] In the diagram: 1. Induction heating element; 2. Melting crucible; 3. Inner wall peeling and cleaning element; 31. Auxiliary shovel; 311. Fixing ring; 312. Shovel plate; 32. Peeling element; 321. Fixing shaft; 322. Three-jaw peeling frame; 323. Peeling gear; 324. Horizontal mounting slot; 325. Rotating shaft; 326. Limiting screw hole; 327. Adjusting bolt; 33. Peeling drive element; 330. Dust cover; 331. Drive motor; 332. Driving gear; 333. Driven gear; 334. Bearing; 335. Connecting shaft; 336. Connecting crossbar; 34. Lifting element; 341. Lifting cover plate. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see the appendix Figures 1-3 As shown, a vacuum induction melting and casting furnace for NdFeB magnet production includes an induction heating element 1 located inside the furnace and a melting crucible 2 enclosing the induction heating element 1. The induction heating element 1, located inside the furnace, is annularly enclosing the outside of the melting crucible 2. It employs a medium-frequency induction coil structure and is connected to an external medium-frequency induction power supply. Through the principle of electromagnetic induction, it generates an alternating magnetic field, causing eddy currents in the metal raw material inside the crucible and generating heat, achieving high-temperature melting exceeding 1300℃, thus providing a heat source for the melting and alloying of NdFeB raw materials. The melting crucible 2, made of boron nitride, is fixed inside the induction heating element 1 and has a columnar structure with an open top. Serving as a melting container for NdFeB basic raw materials and trace elements such as dysprosium and terbium, it can withstand temperatures exceeding 1300℃ and has strong chemical inertness, reducing reactions with rare earth elements. The top of the smelting crucible 2 is equipped with an inner wall stripping and cleaning component 3 for cleaning its inner wall. This component is used to automatically clean the residue on the inner wall of the crucible. The inner wall stripping and cleaning component 3 includes an auxiliary scraping component 31, a stripping component 32, a stripping drive component 33, and a lifting component 34. The four components work together to achieve the cleaning functions of preliminary scraping, fine grinding, automatic drive, and full height coverage.

[0024] Please see the appendix Figures 2-5 As shown, the auxiliary scraping component 31 includes a fixing ring 311 and a scraping plate 312. The fixing ring 311 is an annular structure, coaxially sleeved on the outside of the peeling drive component 33. The scraping plate 312 is symmetrically distributed on both sides of the bottom of the fixing ring 311. Its outer wall contour is perfectly adapted to the inner wall structure of the melting crucible 2 and fits tightly against the inner wall. The scraping plate 312 has a scraping scraper on the lower inner surface of the side facing the inner wall of the crucible. The scraper is made of silicon nitride ceramic material with a thickness of 3mm and an edge set at a 45° acute angle. During the cleaning process, it moves up and down with the lifting component 34. Through the scraping plate 312 and the acute-angled scraper that fit against the inner wall, the solid alloy adhering material on the inner wall of the crucible behind the glass of the peeling component 32 is directly scraped off, laying the foundation for subsequent fine cleaning. The 45° acute-angled edge can penetrate into the tiny recesses of the inner wall of the crucible.

[0025] The peeling component 32 includes a fixed shaft 321, a three-jaw peeling frame 322, and peeling gears 323. The fixed shaft 321 is a vertical rod-shaped structure, and its top is connected to the peeling drive component 33 for transmission. The top of the three-jaw peeling frame 322 is fixedly connected to the bottom of the fixed shaft 321, and the three claws are evenly distributed radially. The ends of the three claws of the three-jaw peeling frame 322 are all provided with horizontal mounting grooves 324. The peeling gears 323 are installed in the horizontal mounting grooves 324 through the rotating shaft 325, and the three peeling gears 323 are distributed radially, with their rims tangent to the inner wall of the melting crucible 2. The three claws of the three-claw peeling frame 322 each have a limiting screw hole 326 near the top of one outer edge. An adjusting bolt 327 passes through the limiting screw hole 326, and the bottom of the adjusting bolt 327 extends into the horizontal mounting groove 324 of the claw, abutting against the inner side of the tooth groove of the peeling gear 323. The adjusting bolt 327 is a detachable structure. By unscrewing the adjusting bolt 327, the peeling gear 323 can be rotated to adjust the contact position of its outermost rim (see Appendix for details). Figure 5 (As shown). Driven by the peeling drive 33, the device rotates around the fixed shaft 321. The peeling gear 323 rolls along the inner wall of the crucible while revolving with the frame, scraping away stubborn residue with its teeth for fine cleaning. When the gear experiences localized wear, the adjusting bolt 327 can be unscrewed to rotate the peeling gear 323, adjusting the contact position of its outermost rim to prevent cleaning failure due to wear. The radial distribution of the three claws combined with the rolling contact of the gears covers the inner wall of the crucible, eliminating cleaning dead angles and ensuring uniform scraping force, avoiding rigid scraping damage to the crucible. The adjusting bolt design allows for flexible adjustment of the gear contact position, enabling alternating wear surfaces, extending gear life, and reducing consumable costs.

[0026] The stripping drive component 33 includes a dust cover 330, a drive motor 331, a drive gear 332, a driven gear 333, a bearing 334, and a connecting shaft 335. The dust cover 330 is a cylindrical structure with an open top. The bearing 334 is sleeved on the outer circumferential wall below the connecting shaft 335. The top of the fixed shaft 321 passes through the dust cover 330 and is fixedly sleeved on the outside of the bearing 334. The driven gear 333 is sleeved on the outside of the fixed shaft 321 at the top of the dust cover 330. The drive gear 332 meshes with one side of the driven gear 333. The output end of the drive motor 331 is connected to the drive gear 332. The outer circumferential wall above the connecting shaft 335 is connected to the inner wall of the top of the dust cover 330 through a connecting crossbar 336. The outer wall of the dust cover 330 is connected to the inner wall of the fixing ring 311. The drive motor 331, through gear transmission, drives the fixed shaft 321 to rotate via the driving gear 332 and the driven gear 333. This, in turn, drives the three-jaw peeling frame 322 and the peeling gear 323 of the peeling component 32 to rotate, providing power for fine cleaning. The dust cover 330 isolates the high temperature and debris inside the crucible, protecting the drive motor 331, gears, and other components. The gear transmission has high stability and high power transmission efficiency, and can precisely control the rotation speed of the peeling gear 323. The dust cover 330 and the connecting crossbar 336 form a closed and stable transmission space, preventing high temperature and debris from damaging the drive components and extending the life of the drive system. It is connected to the fixing ring 311 of the auxiliary scraper 31 to achieve the integration of the cleaning components and ensure synchronous movement.

[0027] The lifting component 34 includes a lifting cover plate 341. The bottom of the lifting cover plate 341 is connected to the top of the connecting shaft 335, and the top of the lifting cover plate 341 is connected to an external lifting motor. Driven by the external lifting motor, the entire inner wall peeling and cleaning component 3, including the auxiliary scraper 31, the peeling component 32, and the peeling drive component 33, moves up and down along the axial direction of the melting crucible 2, so that the cleaning structure covers the entire height of the crucible from top to bottom, avoiding cleaning dead corners in the height direction. The lifting control is automated, requiring no manual operation, and is adaptable to crucibles of different heights. The lifting speed can be adjusted by the control system in conjunction with the rotation speed of the peeling component 32.

[0028] Workflow: After melting, the induction heating element 1 is turned off. The temperature of the melting crucible 2 is allowed to drop to a safe range, maintaining an inert atmosphere inside the furnace. The lifting element 34 is activated, causing the inner wall stripping and cleaning element 3 to slowly descend until the stripping element 32, located below the auxiliary scraper 31, enters the crucible. The rim of the stripping gear 323 is tangential to the inner wall of the crucible bottom. The drive motor 331 of the stripping drive element 33 is activated. Through the meshing of the driving gear 332 and the driven gear 333, the fixed shaft 321 and the three-jaw stripping frame 322 rotate synchronously. While the stripping gear 323 revolves with the frame, it rolls along the inner wall of the crucible, its teeth penetrating deep into the surface. Stubborn residues (rare earth oxides, borides, crucible debris) are scraped and removed from the gaps. During this process, the lifting component 34 slowly lowers the cleaning component, ensuring that the stripping gear 323 cleans from top to bottom without any blind spots in the vertical direction. As the stripping component 32 descends, the auxiliary scraper 31 descends synchronously with the cleaning component. Its symmetrically distributed scraper plates 312 and 45° acute-angle silicon nitride ceramic scrapers perform a secondary scraping of the loose solid alloy adhering material after the stripping component 32 has been scraped. The acute-angle scraper can penetrate into the tiny recesses of the crucible's inner wall, removing dead corners that the stripping gear 323 teeth cannot reach, ensuring that the residue on the inner wall is completely removed. When the stripping component 32 descends to the bottom of the crucible and the auxiliary scraper 31 has completed full-height scraping, the drive motor 331 is turned off, and the lifting component 34 is activated to raise the inner wall stripping and cleaning component 3 to the top of the crucible and reset it. The furnace body is opened, the crucible is tilted, and the single cleaning operation is completed.

[0029] When the position of the stripping gear 323 needs to be adjusted, the outermost rim of the stripping gear 323 can be rotated by unscrewing the adjusting bolt 327 to adjust the contact position, thus avoiding cleaning failure caused by wear. The adjusting bolt 327 is designed to flexibly adjust the gear contact position, realize the alternation of wear surfaces, extend the service life of the gear, and reduce consumable costs.

[0030] This application features a two-stage cleaning process and full-height coverage, resulting in a high residue removal rate, eliminating melt contamination, and ensuring magnet purity; the automated cleaning process also ensures high efficiency.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0032] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A vacuum induction melting and casting furnace for producing neodymium iron boron magnets, comprising an induction heating element (1) located inside the melting and casting furnace and a melting crucible (2) enclosing the induction heating element (1), characterized in that: The top of the smelting crucible (2) is provided with an inner wall stripping and cleaning component (3) for cleaning its inner wall. The inner wall stripping and cleaning component (3) includes an auxiliary scraping component (31), a stripping component (32), a stripping drive component (33), and a lifting component (34). The auxiliary scraping component (31) includes a fixing ring (311) and a scraping plate (312). The scraping plate (312) is symmetrically distributed on both sides of the bottom of the fixing ring (311). The outer contour of the scraping plate (312) is adapted to the inner wall structure of the smelting crucible (2) and fits tightly against the inner wall. It is used to scrape and clean the solid alloy adhering on the inner wall of the smelting crucible (2).

2. The vacuum induction melting and casting furnace for producing neodymium iron boron magnets according to claim 1, characterized in that: The peeling component (32) includes a fixed shaft (321), a three-jaw peeling frame (322), and peeling gears (323). The top of the three-jaw peeling frame (322) is fixedly connected to the bottom of the fixed shaft (321). The ends of the three claws of the three-jaw peeling frame (322) are provided with horizontal mounting grooves (324). The peeling gears (323) are installed in the horizontal mounting grooves (324) through a rotating shaft (325). The three peeling gears (323) are radially distributed, and their rims are tangent to the inner wall of the melting crucible (2).

3. The vacuum induction melting and casting furnace for producing neodymium iron boron magnets according to claim 2, characterized in that: The three claws of the peeling frame (322) have limit screw holes (326) on the top of the outer edge of each claw. An adjusting bolt (327) is inserted into the limit screw hole (326). The bottom of the adjusting bolt (327) extends into the horizontal mounting groove (324) of the claw and abuts against the inner side of the tooth groove of the peeling gear (323). The adjusting bolt (327) is a detachable structure. By unscrewing the adjusting bolt (327), the peeling gear (323) can be rotated to adjust the contact position of its outermost rim.

4. The vacuum induction melting and casting furnace for producing neodymium iron boron magnets according to claim 3, characterized in that: The stripping drive component (33) includes a dust cover (330), a drive motor (331), a drive gear (332), a driven gear (333), a bearing (334), and a connecting shaft (335). The bearing (334) is sleeved on the outer circumferential wall below the connecting shaft (335). The top of the fixed shaft (321) passes through the dust cover (330) and is fixedly sleeved on the outside of the bearing (334). The driven gear (333) is sleeved on the... Outside the fixed shaft (321) at the top of the dust cover (330), the driving gear (332) meshes with one side of the driven gear (333), the output end of the drive motor (331) is connected to the driving gear (332), the outer circumferential wall above the connecting shaft (335) is connected to the inner wall of the top of the dust cover (330) through the connecting crossbar (336), and the outer wall of the dust cover (330) is connected to the inner wall of the fixing ring (311).

5. The vacuum induction melting and casting furnace for producing neodymium iron boron magnets according to claim 4, characterized in that: The lifting component (34) includes a lifting cover plate (341), the bottom of which is connected to the top of the connecting shaft (335), and the top of which is connected to an external lifting motor.

6. The vacuum induction melting and casting furnace for producing neodymium iron boron magnets according to claim 1, characterized in that: The scraping plate (312) has a scraping scraper on the inner surface of the side facing the inner wall of the melting crucible (2). The scraping scraper is made of silicon nitride ceramic material with a thickness of 3mm and the edge of the scraping scraper is set at a 45° acute angle.

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