Preparation method of radiation tile-shaped sintered neodymium-iron-boron magnet and forming device thereof

Abstract

This application relates to a method and forming apparatus for preparing radial tile-shaped sintered NdFeB magnets. The forming apparatus includes a heating mold, an extrusion mold, and an extrusion punch. The heating mold has a through-hole cavity and is fixedly mounted on the lower slide of a hot press. A heating coil is mounted on the hot press and fitted outside the heating mold. The extrusion mold is a cylinder embedded in the inner cavity of the heating mold. The extrusion punch is fixedly mounted in the center of the upper slide of the hot press. The preparation method involves first obtaining NdFeB powder with a particle size of 3-4 μm, magnetizing and sintering it into sintered square sheets, applying a release agent, preheating and holding it at 500-950℃ in an extrusion mold, and then hot-extending it at a speed of 0.01-1 mm / s for slight deformation to obtain the radial tile-shaped sintered magnet. The forming apparatus and preparation method of this application produce radial tile-shaped sintered magnets with high orientation, excellent magnetic properties, controllable forming dimensions, and high material utilization.

Description

Technical Field

[0001] This application relates to the technical field of sintered NdFeB magnets, and in particular to a method for preparing radial tile-shaped sintered NdFeB magnets and a forming apparatus thereof. Background Technology

[0002] Permanent magnet servo motors are widely used worldwide due to their high efficiency and low power consumption. The radially oriented neodymium iron boron (NdFeB) magnets are the core component that determines the performance of a permanent magnet servo motor. Currently, the NdFeB magnets used in commercially available permanent magnet servo motors are horizontally oriented, which is incompatible with the motor and prevents the full utilization of the sintered NdFeB magnets, resulting in a waste of magnetic energy. To fully utilize the magnet's performance, some magnet manufacturers have begun developing single-piece radially oriented magnetic tiles.

[0003] Utility model patent CN215731300U discloses a radially oriented sintered NdFeB magnetic tile and its forming device, including a left mold body and a right mold body. Each of the left and right mold bodies has an interlocking mold cavity on its opposite side. A first magnetic guiding block is disposed inside the left mold body, and a second magnetic guiding block is disposed inside the right mold body. A fixing mechanism is provided between the two sides of the left and right mold bodies. This patent solves the problem of easy damage during tile forming and material handling, but it does not solve the problems of uncontrollable finished product size and uneven orientation.

[0004] CN101867267B discloses a manufacturing process and molding die for radially oriented NdFeB magnet tiles for motors. A square NdFeB green blank obtained by conventional methods is placed in the recessed portion of a sintered ceramic plate in the molding die for sintering. Under high temperature and gravity, the blank located above the recessed portion of the molding die bends and deforms towards the recessed portion, ultimately obtaining radially oriented NdFeB magnet tiles. Because the bending of the blank relies on gravity, problems such as uncontrollable finished product dimensions and uneven orientation still exist. Summary of the Invention

[0005] To address the issues of uncontrollable finished product dimensions and uneven orientation in existing radially oriented tile-shaped NdFeB magnets, this application provides a method for preparing radially oriented tile-shaped sintered NdFeB magnets and its forming apparatus.

[0006] This application provides a radial tile-shaped sintered NdFeB magnet forming device, which adopts the following technical solution: A radial tile-shaped sintered NdFeB magnet forming device includes a heating mold, an extrusion mold, and an extrusion punch. The heating mold has a through-hole cavity and is fixedly mounted on the lower slide of a hot press device by a mold plate. The hot press device is provided with a heating coil sleeved outside the heating mold. The extrusion mold is a cylinder embedded in the inner cavity of the heating mold. The extrusion punch is fixedly mounted in the center of the upper slide of the hot press device.

[0007] Furthermore, the extrusion die includes a left extrusion die and a right extrusion die, and an extrusion deformation cavity is formed between the left extrusion die and the right extrusion die.

[0008] Furthermore, the extrusion deformation cavity is divided into a heating zone and a deformation zone.

[0009] Furthermore, the heating die and the extrusion punch are made of cemented carbide.

[0010] Furthermore, the extrusion die is made of ceramic.

[0011] A method for preparing a radial tile-shaped sintered NdFeB magnet includes the following steps: Step S1: Obtain NdFeB alloy thin strips according to the rapid solidification thin strip process. Then, treat the NdFeB alloy thin strips with hydrogen and perform air jet milling to obtain powder with a particle size X. 50 =3-4μm neodymium iron boron powder; Step S2: The above-mentioned NdFeB powder is placed into the mold cavity for magnetization and molding to obtain NdFeB green blanks. The orientation of the NdFeB green blanks is parallel orientation. Step S3: Sinter and age the formed NdFeB green blank to obtain the required sintered square sheet; Step S4: Apply release agent evenly to all six sides of the sintered square sheet; Step S5: Under argon protection, the heating die and extrusion die are preheated by the heating coil of the lower slider of the hot pressing equipment at a preheating temperature of 500℃-950℃. Step S6: After the extrusion die reaches the preheating temperature, place the sintered square sheet into the extrusion deformation cavity of the extrusion die and hold it for 3-15 minutes. Step S7: The extrusion punch 3 moves at a constant speed to extrude the sintered square sheet. The extrusion speed is 0.01 mm / s-1 mm / s. The sintered square sheet gradually undergoes slight deformation and bending in the deformation zone of the extrusion deformation cavity, and finally obtains a radial tile-shaped sintered NdFeB magnet.

[0012] Furthermore, the radially shaped sintered NdFeB magnet has a radius of 10mm-35mm, an orientation angle of 20°-100°, a thickness of 4mm-5mm, a height of 15mm-25mm, and an orientation of radially shaped.

[0013] Furthermore, the mold heating temperature in step S5 is 850°C.

[0014] Furthermore, the heat preservation time in step S6 is 3 minutes.

[0015] Furthermore, the extrusion speed in step S7 is 1 mm / s.

[0016] In summary, this application includes at least one of the following beneficial technical effects: 1. Using the radial tile-shaped sintered NdFeB magnet forming device of the present invention, sintered NdFeB square sheets are extruded in one step to form radial tile-shaped sintered NdFeB magnets with a radius of 10mm-35mm, an orientation angle of 20°-100°, a thickness of 4mm-5mm, and a height of 15mm-25mm, achieving a high material utilization rate, small processing allowance, and controllable magnet tile forming size; 2. This invention achieves rapid heating of the mold and provides uniform heat preservation for the blank through inductive heating, creating a precise and controllable high-temperature environment. Subsequently, radial tile-shaped sintered NdFeB magnets are formed by constant-speed extrusion. This simultaneous "thermal-mechanical" process greatly improves material utilization and production efficiency. By suppressing grain coarsening and promoting densification, tile-shaped magnets with high dimensional accuracy, high consistency, and excellent magnetic properties are directly obtained. 3. Based on powder particle size X 50 Radial tile-shaped sintered NdFeB magnets prepared from anisotropic sintered square sheets obtained by processing NdFeB powder with a diameter of 3-4 μm exhibit excellent magnetic properties and high orientation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a radial tile-shaped sintered NdFeB magnet forming device. Figure 2 This is a schematic diagram of the extrusion die in this invention; Figure 3 This is a schematic diagram of the orientation of the sintered square sheet in this invention; Figure 4 This is a schematic diagram of the orientation and orientation angle of the extruded billet in this invention; Figure 5 This is the XRD pattern of the elongated sample in Example 1; Figure 6 This is the XRD pattern of the elongated sample in Example 2; Figure 7 This is the XRD pattern of the elongated sample in Example 3; Figure 8 The XRD pattern of the elongated sample in Comparative Example 1 is shown. Figure 9 The XRD pattern of the elongated sample in Comparative Example 2 is shown. Figure 10The XRD pattern of the long strip sample in Comparative Example 3 is shown. Figure 11 This is the XRD pattern of the long strip sample in Comparative Example 4.

[0018] Explanation of reference numerals in the attached drawings: 1. Heating mold sleeve; 2. Extrusion mold; 21. Left extrusion mold; 22. Right extrusion mold; 3. Extrusion punch; 4. Sintered square sheet; 5. Extrusion deformation cavity; 51. Heating zone; 52. Deformation zone; 6. Heating coil; 7. Lower slider; 8. Mold sleeve pressure plate; 9. Upper slider. Detailed Implementation

[0019] The present application will be further described in detail below with reference to all the accompanying drawings.

[0020] This application discloses a radial tile-shaped sintered NdFeB magnet forming device.

[0021] A radial tile-shaped sintered NdFeB magnet forming device includes a heating mold sleeve 1, an extrusion mold 2, and an extrusion punch 3. The heating mold sleeve 1 is a hollow cylinder with openings at both the top and bottom ends, fixed on the lower slide block 7 of a hot press equipment. The heating mold sleeve is fixed by the lower slide block 7. A heating coil 6 is provided on the hot press equipment, which is fitted outside the heating mold sleeve 1. The heating mold sleeve 1 is located in the center of the heating coil 6. The extrusion punch 3 is fixedly installed in the center of the upper slide block 9 of the hot press equipment. The upper slide block 9 can move along the height direction. The heating mold sleeve 1 is fixedly installed on the lower slide block 7 of the hot press equipment by a mold sleeve pressure plate 8. The heating coil 6 is an electromagnetic induction coil, which heats the environment of the heating mold sleeve 1 by inductive heating.

[0022] The upper slider 9 is moved by a stamping device, which is existing technology and will not be described in detail here.

[0023] The extrusion die 2 is divided into two parts: a left extrusion die 21 and a right extrusion die 22. Both are cylinders with the same outer diameter as the inner diameter of the heating sleeve 1. The left and right extrusion dies 21 and 22 together form the extrusion deformation cavity 5, which includes a heating zone 51 and a deformation zone 52. The extrusion punch 3 has the same dimensions as the heating zone 51 of the extrusion deformation cavity 5 of the extrusion die 2 and is fixed in the center of the upper slide block of the hot press equipment. It is used to extrude and sinter the square sheet 4.

[0024] The heating zone 51 has a rectangular longitudinal section, and the deformation zone 51 has a tile-shaped longitudinal section. The heating zone 51 and the deformation zone 52 have a smooth transition.

[0025] Sintered square sheet 4 is an anisotropic neodymium iron boron magnet formed by sintering, and the orientation direction of sintered square sheet 4 is the thickness direction.

[0026] The device for forming irregularly shaped sintered NdFeB deformable magnets uses cemented carbide for heating die sleeve 1 and extrusion punch 3, and ceramic for extrusion die 2.

[0027] This invention also proposes a method for preparing radial tile-shaped sintered NdFeB magnets, which includes the following steps: Step S1: Obtain NdFeB alloy thin strips according to the rapid solidification thin strip process. Then, treat the NdFeB alloy thin strips with hydrogen and perform air jet milling to obtain powder with a particle size X. 50 =3-4μm neodymium iron boron powder; Step S2: The above-mentioned NdFeB powder is placed into the mold cavity for magnetization and molding to obtain NdFeB green blanks. The orientation of the NdFeB green blanks is parallel orientation. Step S3: Sinter and age the formed NdFeB green blank to obtain the required sintered square sheet 4; Step S4: Evenly coat all six sides of the sintered square sheet 4 with a release agent; Step S5: Under argon protection, the heating mold sleeve 1 and extrusion mold 2 are preheated by the heating coil 6 of the lower slider 7 of the hot pressing equipment. The preheating temperature is 500℃-950℃. Step S6: After the extrusion die 2 reaches the preheating temperature, the sintered square sheet 4 is placed into the extrusion deformation cavity 5 of the extrusion die 2 and kept warm for 3 min-15 min. Step S7: The extrusion punch 3 moves at a constant speed to extrude the sintered square sheet 4. The extrusion speed is 0.01 mm / s-1 mm / s. The sintered square sheet 4 gradually undergoes slight deformation and bending in the deformation zone 52 of the extrusion deformation cavity 5, and finally obtains a radial tile-shaped sintered NdFeB magnet.

[0028] The present invention will be further described in detail below with reference to specific embodiments in order to better understand and implement it.

[0029] Example 1: This example provides a method for preparing a radial tile-shaped sintered NdFeB magnet, the operation steps of which are as follows: Step S1: Obtain NdFeB alloy thin strips according to the rapid solidification thin strip process. Then, treat the NdFeB alloy thin strips with hydrogen and perform air jet milling to obtain powder with a particle size X. 50 =3.0μm NdFeB powder.

[0030] Step S2: The above-mentioned NdFeB powder is placed into the mold cavity for magnetization and molding to obtain NdFeB green blanks. The orientation of the NdFeB green blanks is parallel orientation.

[0031] Step S3: Sinter and age the formed NdFeB green blank to obtain a sintered square sheet 4 with a thickness of 4.8 mm and a height of 25.4 mm.

[0032] Step S4: Coat all six sides of the sintered square sheet 4 with a release agent.

[0033] Step S5: Under argon protection, the heating mold sleeve 1 and extrusion mold 2 are preheated by the heating coil 6 of the lower slider 7 of the hot pressing equipment. The preheating temperature is 850℃ and the heating rate is 15℃ / s.

[0034] Step S6: When the extrusion mold 2 reaches 850°C, place the sintered square sheet 4 into the extrusion mold and keep it at that temperature for 3 minutes.

[0035] Step S7: The extrusion punch 3 moves at a constant speed to extrude the sintered square sheet. The extrusion speed is 1 mm / s. The sintered square sheet gradually undergoes slight deformation and bending in the deformation zone of the extrusion deformation cavity, and finally obtains a radial tile-shaped sintered NdFeB magnet with an orientation angle of 20°, a radius of 34.5 mm, a thickness of 4.5 mm, and a height of 25 mm.

[0036] A long strip sample with a length of 10 mm and a width of 5 mm was cut using a wire cutting device. The arc surface was polished flat. Phase analysis was performed using XRD (X-ray diffractometer). The orientation degree was characterized by the characteristic peaks I(006) / I(105).

[0037] Example 2: This example provides a method for preparing a radial tile-shaped sintered NdFeB magnet, the operation steps of which are as follows: Step S1: Obtain NdFeB alloy thin strips according to the rapid solidification thin strip process. Then, treat the NdFeB alloy thin strips with hydrogen and perform air jet milling to obtain powder with a particle size X. 50 =3.0μm NdFeB powder.

[0038] Step S2: The above-mentioned NdFeB powder is placed into the mold cavity for magnetization and molding to obtain NdFeB green blanks. The orientation of the NdFeB green blanks is parallel orientation.

[0039] Step S3: The formed NdFeB green blank is sintered and aged to obtain a sintered square sheet with a thickness of 4.7 mm and a height of 15.4 mm.

[0040] Step S4: Coat all six sides of the sintered square sheet 4 with a release agent.

[0041] Step S5: Under argon protection, the heating mold sleeve 1 and extrusion mold 2 are preheated by the heating coil 6 of the lower slider 7 of the hot pressing equipment. The preheating temperature is 950℃ and the heating rate is 15℃ / s.

[0042] Step S6: When the extrusion mold 2 reaches 950°C, place the sintered square sheet 4 into the extrusion mold and keep it at that temperature for 15 minutes.

[0043] Step S7: The extrusion punch 3 moves at a constant speed to extrude and sinter the square sheet. The extrusion speed is 0.5 mm / s. The sintered square sheet 4 gradually undergoes slight deformation and bending in the deformation zone 52 of the extrusion deformation cavity 5, and finally obtains a radial tile-shaped sintered NdFeB magnet with an orientation angle of 30°, a radius of 12 mm, a thickness of 4 mm, and a height of 15 mm.

[0044] A long strip sample with a length of 10 mm and a width of 5 mm was cut using a wire cutting device. The arc surface was polished flat. Phase analysis was performed using XRD (X-ray diffractometer). The orientation degree was characterized by the characteristic peaks I(006) / I(105).

[0045] Example 3: This example provides a method for preparing a radial tile-shaped sintered NdFeB magnet, the operation steps of which are as follows: Step S1: Obtain NdFeB alloy thin strips according to the rapid solidification thin strip process. Then, treat the NdFeB alloy thin strips with hydrogen and perform air jet milling to obtain powder with a particle size X. 50 =3.5μm NdFeB powder.

[0046] Step S2: The above-mentioned NdFeB powder is placed into the mold cavity for magnetization and molding to obtain NdFeB green blanks. The orientation of the NdFeB green blanks is parallel orientation.

[0047] Step S3: The formed NdFeB green blank is sintered and aged to obtain a sintered square sheet with a thickness of 5.4 mm and a height of 25.4 mm.

[0048] Step S4: Coat all six sides of the sintered square sheet 4 with a release agent.

[0049] Step S5: Under argon protection, the heating mold sleeve 1 and extrusion mold 2 are preheated by the heating coil 6 of the lower slider 7 of the hot pressing equipment. The heating temperature of the mold is 500℃ and the heating rate is 15℃ / s.

[0050] Step S6: When the extrusion mold 2 reaches 500°C, place the sintered square sheet 4 into the extrusion mold and keep it at that temperature for 12 minutes.

[0051] Step S7: The extrusion punch 3 moves at a constant speed to extrude and sinter the square sheet 4. The extrusion speed is 0.01 mm / s. The sintered square sheet 4 gradually undergoes slight deformation and bending in the deformation zone 52 of the extrusion deformation cavity 5, and finally obtains a radial tile-shaped sintered NdFeB magnet with an orientation angle of 100°, a radius of 10 mm, a thickness of 5 mm, and a height of 25 mm.

[0052] A long strip sample with a length of 10 mm and a width of 5 mm was cut using a wire cutting device. The arc surface was polished flat. Phase analysis was performed using XRD (X-ray diffractometer). The orientation degree was characterized by the characteristic peaks I(006) / I(105).

[0053] Comparative Example 1: Radial orientation magnetic tile green blanks with a thickness of 5.1 mm and a height of 26 mm were prepared by first molding and then isostatic pressing. Then, the green blanks were sintered, aged and ground. The sintering temperature was 1020℃ and the heating rate was 10℃ / min. Finally, tile-shaped sintered NdFeB magnets with an orientation angle of 20°, a radius of 34.5 mm, a thickness of 4.5 mm and a height of 25 mm were obtained.

[0054] A long strip sample with a length of 10 mm and a width of 5 mm was cut using a wire cutting device. The arc surface was polished flat. Phase analysis was performed using XRD (X-ray diffractometer). The orientation degree was characterized by the characteristic peaks I(006) / I(105).

[0055] Comparative Example 2: Radial orientation magnetic tile green blanks with a thickness of 4.6 mm and a height of 16.3 mm were prepared by first molding and then isostatic pressing. Then, after sintering, aging and grinding, a tile-shaped sintered NdFeB magnet with an orientation angle of 30°, a radius of 12 mm, a thickness of 4 mm and a height of 15 mm was finally obtained.

[0056] A long strip sample with a length of 10 mm and a width of 5 mm was cut using a wire cutting device. The arc surface was polished flat. Phase analysis was performed using XRD (X-ray diffractometer). The orientation degree was characterized by the characteristic peaks I(006) / I(105).

[0057] Comparative Example 3: A radiative oriented magnetic tile green blank with a thickness of 5.8 mm and a height of 26.2 mm was prepared by first molding and then isostatic pressing. Then, the green blank was obtained by sintering, aging and grinding. The sintering temperature was 1050℃ and the heating rate was 10℃ / min. Finally, a tile-shaped sintered NdFeB magnet with an orientation angle of 100°, a radius of 10 mm, a thickness of 5 mm and a height of 25 mm was obtained.

[0058] A long strip sample with a length of 10 mm and a width of 5 mm was cut using a wire cutting device. The arc surface was polished flat. Phase analysis was performed using XRD (X-ray diffractometer). The orientation degree was characterized by the characteristic peaks I(006) / I(105).

[0059] Comparative Example 4: Rapidly quenched NdFeB powder with a particle size of 200-400μm is shaped to obtain a non-oriented green blank, which is then hot-pressed to obtain an isotropic hot-pressed magnet. Finally, the isotropic hot-pressed magnet is hot-extruded to obtain an anisotropic tile-shaped sintered NdFeB magnet with an orientation angle of 30°, a radius of 34.5mm, a thickness of 4.5mm, and a height of 25mm. The hot extrusion temperature is 850℃.

[0060] A long strip sample with a length of 10 mm and a width of 5 mm was cut using a wire cutting device. The arc surface was polished flat. Phase analysis was performed using XRD (X-ray diffractometer). The orientation degree was characterized by the characteristic peaks I(006) / I(105).

[0061] Comparing the dimensions before and after processing in Examples 1-3 and Comparative Examples 1-3, it can be seen that the amount of grinding required for processing radiant tile magnets made using the process method and apparatus of the present invention can be reduced by 25%-50%.

[0062] The magnetic properties and XRD characteristic peak ratios of the tile-shaped sintered NdFeB magnets obtained by the above method are shown in Table 1.

[0063] Table 1. Magnetic properties and XRD characteristic peak ratios of tile-shaped sintered NdFeB magnets

[0064] The magnetic properties of Examples 1-3 and Comparative Examples 1-3 can be compared with those of Comparative Examples 1-3. The radiant tile magnets prepared by the method and apparatus of the present invention in Examples 1-3 have a Br value that is more than 2% higher and an Hcj value that is more than 2.5% higher than that of the magnetic tiles directly obtained by conventional sintering magnets in Comparative Examples 1-3, and their magnetic properties are significantly improved.

[0065] Compared to the magnetic properties of the magnetic tiles obtained by hot-pressing and rapidly quenching powder with a coarser particle size in Comparative Example 4, the magnetic tiles prepared in Examples 1-3, due to the use of NdFeB magnets with a finer particle size, achieved higher Br and Hcj values. The magnetic tiles prepared by the method of this invention exhibit a Br value increased by more than 5% and an Hcj value increased by more than 33%, demonstrating significant performance advantages.

[0066] Compared with the magnetic tiles directly obtained from conventional sintered magnets in Comparative Examples 1-3, the magnetic tiles prepared using the method of the present invention in Examples 1-3 have a higher characteristic peak I(006) / I(105) value by more than 0.2. Compared with the magnetic tiles obtained from hot-pressed and rapidly quenched powder with coarser particle size in Comparative Example 4, the magnetic tiles prepared in Examples 1-3 have a higher characteristic peak I(006) / I(105) value by more than 0.5 due to the use of neodymium iron boron magnets with finer particle size, indicating that the magnetic tiles prepared using the present invention have a high degree of orientation.

[0067] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A device for forming radial tile-shaped sintered NdFeB magnets, characterized in that, The device includes a heating mold sleeve (1), an extrusion mold (2), and an extrusion punch (3). The heating mold sleeve (1) has an inner cavity. The heating mold sleeve (1) is fixedly installed on the lower slide block (7) of the hot press equipment by a mold sleeve pressure plate (8). The hot press equipment is provided with a heating coil (6) sleeved outside the heating mold sleeve (1). The extrusion mold (2) is a cylinder embedded in the inner cavity of the heating mold sleeve (1). The extrusion punch (3) is fixedly installed in the center of the upper slide block (9) of the hot press equipment. The extrusion mold (2) includes a left extrusion mold (21) and a right extrusion mold (22). An extrusion deformation cavity (5) is formed between the left extrusion mold (21) and the right extrusion mold (22). The extrusion deformation cavity (5) is divided into a heating zone (51) and a deformation zone (52). The heating mold sleeve (1) and the extrusion punch (3) are made of hard alloy, and the extrusion mold (2) is made of ceramic.

2. A method for preparing a radially shaped sintered NdFeB magnet, wherein the method uses the radially shaped sintered NdFeB magnet forming apparatus described in claim 1, characterized in that, Includes the following steps: Step S1: Obtain NdFeB alloy thin strips according to the rapid solidification thin strip process. Then, treat the NdFeB alloy thin strips with hydrogen and perform air jet milling to obtain powder with a particle size X. 50 Neodymium iron boron powder with a diameter of 3-4 μm; Step S2: The above-mentioned NdFeB powder is placed into the mold cavity for magnetization and molding to obtain NdFeB green blanks. The orientation of the NdFeB green blanks is parallel orientation. Step S3: Sinter and age the formed NdFeB green blank to obtain the required sintered square sheet (4). Step S4: Coat all six sides of the sintered square sheet (4) with a release agent; Step S5: Under argon protection, the heating mold sleeve (1) and extrusion mold (2) are preheated by the heating coil (6) of the lower slide (7) of the hot pressing equipment. The preheating temperature is 500℃-950℃. Step S6: When the extrusion die (2) reaches the preheating temperature, the sintered square sheet (4) is placed into the extrusion deformation cavity (5) of the extrusion die (2) and kept warm for 3 min-15 min. Step S7: The extrusion punch (3) moves at a constant speed to extrude the sintered square sheet (4). The extrusion speed is 0.01 mm / s-1 mm / s. The sintered square sheet (4) gradually undergoes slight deformation and bending in the deformation zone of the extrusion deformation cavity (5), and finally obtains a radial tile-shaped sintered NdFeB magnet. The radially shaped sintered NdFeB magnet has a radius of 10mm-35mm, an orientation angle of 20°-100°, a thickness of 4mm-5mm, a height of 15mm-25mm, and is oriented in a radially shaped manner.

3. The method for preparing a radially shaped sintered NdFeB magnet according to claim 2, characterized in that, The preheating temperature in step S5 is 850°C.

4. The method for preparing a radially shaped sintered NdFeB magnet according to claim 2, characterized in that, The heat preservation time in step S6 is 3 minutes.

5. The method for preparing a radial tile-shaped sintered NdFeB magnet according to claim 2, characterized in that, The extrusion speed in step S7 is 1 mm / s.

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