JPS6210253A - Manufacture of manganese-aluminum-carbon alloy magnet - Google Patents

Abstract

PURPOSE:To obtain superior magnetic characteristics by a small extent of working when a compressive strain is produced in a hollow billet of an Mn-Al-C alloy in the axial direction by plastic working to manufacture an alloy magnet, by previously producing a tensile strain in the extrusion direction by specified extrusion. CONSTITUTION:The cavity in the container part 6 of dies consisting of a mandrel 2 and a die 3 has a hollow cross-sectional shape, and the area of the opening of the container part 6 (the area of the cross-section perpendicular to the extrusion direction) is larger than the area of the opening of the bearing part 7. A billet 1' is put in the container part 6, and after the axial direction is made parallel to the extrusion direction, the billet 1' is pressurized at 530-830 deg.C with a punch 4. A new billet 1 is then put in the container part 6 and pressurized in the same way, and extrusion is carried out by repeating the stages. The outer surface of the extruded billet 1 is restrained, at least part of the inner surface is kept free, and the billet 1 is compressed in the axial direction. Part of the billet may be further compressed as required.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing permanent magnets. More specifically, polycrystalline manganese-aluminum-carbon system (
The present invention relates to a method for manufacturing Mn-AI-C alloy magnets, and particularly provides a method for manufacturing Mn-AI-C alloy magnets for multipolar magnetization.

BACKGROUND ART Mn-A I-C magnet alloy is a general term for Mn-AI-C magnet alloys and Mn-AI-C alloy magnets. The Mn-AI-C alloy for magnets contains 68 to 73 mass% of Mn (hereinafter simply expressed as chi) and (1/1°Mn-
6,6) A multi-element system consisting of ~(1/3 Mn -22,2)% C and the balance AI, including a ternary system containing no additive elements other than impurities and a quaternary or higher system containing a small amount of additive elements. Alloys for magnets are known, and these are collectively referred to as alloys. Similarly, Mn-AI-C alloy magnets are mainly composed of a face-centered tetragonal (τ phase, Ll. regular lattice) structure, which is a ferromagnetic phase, and contain C as an essential constituent element. Multi-component alloy magnets are known, including ternary alloy magnets that do not contain any additive elements other than impurities, and quaternary or higher alloy magnets that contain a small amount of additive elements.

Furthermore, as a manufacturing method of this Mn-AI-C alloy magnet, a method including a warm plastic working process such as warm extrusion process in addition to the method using casting and heat treatment is known. Especially the latter,
It is known as a method for producing anisotropic magnets that have excellent properties such as high magnetic properties, mechanical strength, weather resistance, and machinability.

Manufacturing methods for multipolar magnetized dn-A I-C alloy magnets include isotropic magnets, compression processing, and uniaxially anisotropic multi-pole magnets obtained in advance by known methods such as warm extrusion. A crystalline Mn-AI-C alloy magnet subjected to warm free compression processing in the anisotropic direction (Japanese Patent Application Laid-Open No. 119762/1983)
, and various types of plastic working that apply compressive strain in the axial direction of a hollow billet made of Mn-A I-C magnetic alloy (for example, JP-A-58-182208, JP-A-58-192306) Public bulletin) is known.

Problems to be Solved by the Invention Various types of plastic working that apply compressive strain in the axial direction of a hollow billet made of the above-mentioned Mn-A I-C magnetic alloy (in particular, JP-A No. 58-182208) In other words, polycrystalline Mn that has been made anisotropic in advance
-A A method in which a hollow billet made of an I-C alloy magnet is compressed in the axial direction of the billet, with the outer periphery of the billet constrained and at least a portion of the inner periphery free. For example, a hollow billet made of a uniaxially anisotropic polycrystalline Mn-Al-C alloy magnet obtained by a known method such as extrusion is used. By subjecting the billet to the specific compression process described above,
A magnet that exhibits excellent magnetic properties when magnetized with multiple poles has been obtained. However, the above method requires at least two types of plastic working, extrusion processing and compression Qo processing, and the fin 7) after extrusion processing has an easy magnetization direction in the extrusion direction, and when multipolar magnetized by compression processing, The magnetic anisotropy structure is transformed into a magnet that exhibits excellent magnetic properties. In other words, the billet after extrusion has uniaxial anisotropy with the easy magnetization direction in the axial direction of the billet, and has an anisotropic structure that is not suitable for multipolar magnetization. Furthermore, the magnetic properties in the circumferential direction are improved, and the magnetic anisotropy structure is converted into a magnet that exhibits excellent magnetic properties when magnetized with multiple poles.

In the method described above, a -axis anisotropic magnet (anisotropic magnet not suitable for multipolar magnetization) is first made by extrusion processing, and then a magnet that exhibits excellent magnetic properties when multipolar magnetized is produced by compression processing. Since the structure is changed, the manufacturing method is wasteful in terms of magnetic properties.

The object of the present invention is to obtain excellent magnetic properties with a small amount of processing.

Means for Solving the Problems In order to solve the problems described above, the present invention provides Mn
-A A hollow billet made of an I-C magnetic alloy is prepared using a die in which the cross-sectional shape of the hollow part of the container part is hollow and the opening area of the container part is larger than the opening area of the bearing part. After performing extrusion processing with the axial direction and extrusion direction parallel to each other, and applying tensile strain to the billet in the extrusion direction by the extrusion processing, the outer periphery of the billet is further restrained and at least a part of the inner periphery is freed. The billet is then compressed in the axial direction.

Effect: By the method described above, that is, by performing the specific extrusion process described above and then applying the specific compression process, the process can be performed by performing the previously known extrusion process and then subjecting the specific compression process described above. According to this method, even if the total amount of plastic working is small, a magnet that exhibits excellent magnetic properties when magnetized with multiple poles can be obtained.

Example The present invention provides a hollow billet made of an Mn-AI-C magnetic alloy at a temperature of 530 to 830°C, in which the cross-sectional shape of the hollow part of the container part is hollow, and the opening area of the container part is Using a die larger than the opening area of the bearing part, the billet is extruded with the axial direction parallel to the extrusion direction, and after applying tensile strain to the billet in the extrusion direction by the extrusion process, the billet is further extruded. The billet is compressed in the axial direction with the outer circumference constrained and at least a portion of the inner circumference free.

By performing the extrusion process described above, Mn-A, which has been made anisotropic by conventional extrusion processes, can be
By the method of obtaining an I-C alloy magnet, a magnet that exhibits excellent magnetic properties when subjected to multipolar magnetization even if the amount of strain during compression processing is small can be obtained. does not necessarily have to be continuous plastic working, but may be divided into multiple times.

An example of the extrusion process of the present invention described above will be described with reference to FIG. 1, assuming that the shape of the billet is cylindrical.

FIG. 1(a) shows a cross-sectional view of a portion of the die showing the state before extrusion, and similarly FIG. 1(b) shows the state after extrusion. 1 is a billet, 2 is a mandrel, 3 is a die, and 4 and 5 are punches. The mandrel 2 and the die 3 constitute a die.

In FIG. 1, reference numeral 6 denotes a container section, which accommodates the billet 1 before extrusion processing, and numeral 7 indicates a bearing section, which accommodates the billet 1 after extrusion processing. 8 is a conical part. Also, the opening area of the container section 6 is
The cross-sectional area of the cavity of the container part 6 (perpendicular to the extrusion direction) is approximately the same as the cross-sectional area of the billet 1 in FIG. The area (perpendicular to the extrusion direction) is shown in Figure 1(b).
almost coincides with the cross-sectional area of billet 1.

In FIG. 1, since both the container part 6 and the bearing part 7 are circular with the extrusion shaft at the center, the opening area of the container part 6 is defined by the ring shape formed by the outer diameter and inner diameter of the container part 6. is the area of The cross-sectional shape of the hollow portion of the container portion 6 is the aforementioned ring shape and is hollow. Similarly, the opening area of the bearing part 7 is a ring-shaped area defined by the outer diameter and inner diameter of the bearing part 7. For example, the outer diameter of the container part 6 is 40 mm and the inner diameter is 20 m, and the outer diameter of the bearing part 7 is 50 mm and the inner diameter is 40 mm.
Then, the opening area of the container portion 6 is approximately 942H2, and the opening area of the bearing portion 7 is approximately 70γm12.

In addition, the cross-sectional shape of the hollow portion of the container portion 6 has an outer diameter of 4
It has a ring shape with an inner diameter of 20 mm and an inner diameter of 20 mm.

In other words, the cross-sectional shape of the hollow part of the container part 6 is hollow when cut perpendicular to the extrusion direction with the billet 1 housed in the container part as shown in FIG. 1(a). , the die component (mandrel 2
), billet 1 is located outside of billet 1, and die 3 is located outside of billet 1.

An example of the extrusion processing method will be explained using FIG. 2.

First, as shown in FIG. 2(a), a cylindrical billet 1' is placed in a container section 6. Billet 1' using punch 4
By applying pressure, it becomes as shown in FIG. 2(b). Next, as shown in FIG. 2(C), the billet 1 is newly placed in the container part 6, and the billet 1 is pressurized using the punch 4 in the same manner as described above, as shown in FIG. 2(d). state. Thereafter, extrusion processing is performed by repeating this process.

Another extrusion method is to move the billet 1 from the container part 6 toward the bearing part while pressurizing the billet 1 with the punches 4 and 6 in the state shown in FIG. 2(C). In the figure, the state of billet 1 is shown in Figure 2 (C) to Figure 2 (d)). In order to facilitate insertion, the shape of the cylindrical billet is designed to have a certain amount of clearance. The shape of the hollow portion when the die is cut on a flat plane) is ring-shaped.

The compression process in the next step and the method of applying compressive strain to a portion of the billet in the axial direction of the billet are the same as the previously mentioned known technique (Japanese Patent Laid-Open No. 182208/1983).

Regarding the possible temperature range for plastic working (extrusion working and compression working) as described above, working was possible in the temperature range of 530 to 830°C, but at temperatures exceeding 78°C, the magnetic properties were considerably degraded. A more desirable temperature range was 660 to 760 t.

Next, more specific embodiments of the present invention will be described.

Example 1 The blend composition is 69.5% Mn and 29.3% AI.

Melting and casting 0.5% C and 0.7% Ni, outer diameter 3
A cylindrical billet having a diameter of 0 rm, an inner diameter of 10 mm, and a length of 20 mm was prepared. After holding this billet at 1000°C for 2 hours, it was air-cooled to 800°C, held at 600°C for 30 minutes, and then heat-treated by allowing it to cool to room temperature.

Next, extrusion processing as shown in FIG. 1 was performed at a temperature of 720° C. using a lubricant. In Fig. 1, the outer diameter of the container part of the die is 30 mrn, the inner diameter is 10 mrn,
The outer diameter of the bearing part is 40 mm, and the inner diameter is 35 rmn.
and X is 2C)m. The billet after extrusion had an outer diameter of 40 mm, an inner diameter of 35 mm, and a length of 42.7 m. Next, the outer peripheral surface of the cylindrical billet was restrained using a mold as shown in Fig. 3 through a lubricant, and the inner periphery was left free, and at a temperature of 680 tl. The cylindrical billet was compressed to a length of 20 tnr. In FIG. 3, the third figure (body 3) shows the state before processing, and FIG. 3(b) shows the state after processing. 1 is a billet, 4.5 is a punch, and 9 is an outer mold. Figure 3 (
As shown in a), the outer peripheral surface of the billet 1 is restrained by the outer mold 9. By pressurizing the billet 1 with punches 4 and 5, the billet 1 is compressed in the axial direction.

The inner diameter of the outer mold 9 is 40 rm.

This compressed billet has an outer diameter of 38 yes.

A cylindrical magnet with an inner diameter of 29 mm and a length of 20 mm was magnetized on the outer circumferential surface with 3Q poles. Magnetization is 2000g
A 1500V-C' pulse magnetization was performed using an F oil condenser. The surface magnetic flux density on the outer peripheral surface was measured using a Hall element. For comparison, Mn, AI, C, and Ni having the same composition as described above were melted and cast, and a diameter of 60
A cylindrical billet with a length of 20 m+ was produced. After holding this billet at 1100° C. for 2 hours, it was heat-treated by being allowed to cool to room temperature.

Next, through the lubricant, at a temperature of 7201:
A known extrusion process up to m was carried out. This extrusion rod has a length of 4
Cut to 2.7+Ilj+ and cut to an outer diameter of 40
A cylindrical billet with mr, inner diameter of 35I, and length of 42.7rta was produced. Next, this billet was subjected to the same compression process as described above, and was further cut into a cylindrical shape in the same manner as above, magnetized, and the surface magnetic flux density was measured.

Comparing the above two values, the value of the surface magnetic flux density of the magnet obtained by the method of the present invention was about 1.2 times that of the magnet produced for comparison.

Furthermore, only the outer periphery of the billet was compressed at a temperature of 680° C. using a mold as shown in FIG. 4 using the magnet of the present invention that had just been magnetized. FIG. 4(-) shows the state before processing, and FIG. 4(b) shows the state after processing. 1Q is a fixed punch, 11 is a movable punch, and 12 is a lower mold.

The fixing punch 10 and the lower mold 12 fix and restrain the billet, and the movable punch 11 pressurizes the billet 1, resulting in the state shown in FIG. 4(b), whereby only the outer periphery of the billet is compressed. Processed. Note that the diameter of the punch 1° (inner diameter of the punch 11) is 34. The length of the outer peripheral portion after compression processing was 15 mm. After processing, the billet is machined and made into a cylinder with an outer diameter of 38 mm, magnetized in the same manner as above, and when the surface magnetic flux density values are compared before and after this local compression processing, the value after processing is 0. .2kG higher.

Example 2 The blend composition was 69.4% Mn, 29.3% AI, 0.
A cylindrical billet with an outer diameter of 20 mm, an inner diameter of 5 mm, and a length of 20 mm was prepared by melting and casting 5% C, 0.7% Ni, and 0.1% Ti. After holding this billet at 1100°C for 2 hours, it was air-cooled to 600°C, held at 60°C for 30 minutes, and then heat-treated by allowing it to cool to room temperature.

Next, extrusion processing as shown in FIG. 1 was performed at a temperature of 720° C. using a lubricant. In Fig. 1, the outer diameter of the container part of the die is 20mm, the inner diameter is S-ring, the outer diameter of the bearing part is 3011111mm, and the inner diameter is 26mm.
Or 2011111. After extrusion, the billet had an outer diameter of 30 rms, an inner diameter of 26 mm, and a length of 33.5 layers.Then, this cylindrical billet was molded with a lubricant using a mold as shown in Figure 3. The length of the cylindrical billet was compressed to 16 groups at a temperature of 680°C with the outer peripheral surface of the cylindrical billet restrained and the inner periphery free.In Fig. 3, the inner diameter of the outer mold 9 is It is 30 rms.

This compressed billet has an outer diameter of 29 mm.

As a cylindrical magnet with an inner diameter of 21 mm and a length of 1 FB, the outer circumferential surface is magnetized with 18 poles, and the zero magnetization is pulse magnetized at 1500 V using a 20 oO no lF oil condenser. The surface magnetic flux density on the outer peripheral surface was measured using a Hall element. For comparison, Mn with the same compounding composition as the above-mentioned compounding composition,
Melting and casting AI, C, Ni and Ti, 60 diameters,
A cylindrical billet with a length of 20 mm was produced. After holding this billet at 1000° C. for 2 hours, it was heat-treated by being allowed to cool to room temperature.

Next, a known extrusion process was carried out at a temperature of 720° C. to a diameter of up to 30 mm using a lubricant. This extrusion rod has a length of 33.
Cut to 5m and machined, outer diameter 30mm, inner diameter 26+
A cylindrical billet with o+ and a length of 33.5 ms was prepared. Next, this billet was subjected to the same compression process as described above, and was further cut into a cylindrical shape in the same manner as above, magnetized, and the surface magnetic flux density was measured.

Comparing the above two values, the value of the surface magnetic flux density of the magnet obtained by the method of the present invention was about 1.2 times that of the magnet produced for comparison.

Furthermore, only the outer peripheral portion of the magnet of the present invention, which had just been magnetized, was compressed at a temperature of 680° C. using a mold as shown in FIG. Note that the diameter of the punch 10 (inner diameter of the punch 11) is 24 mm. The length of the outer periphery after compression processing was 10 m. The processed billet was machined to an outer diameter of 29 mm and magnetized in the same manner as described above. Comparing the surface magnetic flux density values before and after this local compression process, the value after processing was 0.2 k.
G has become high.

Example 3 Mn, AI, C, and Ni having the same composition as in Example 1 were melted and cast, and the outer diameter was 40 mm, the inner diameter was 30 B, and the length was 20 mm.
- A cylindrical billet was produced. This billet is 1100
After being kept at ℃ for 2 hours, air-cooled to eooc and then heated to 600℃.
After holding the sample for 30 minutes, heat treatment was performed by allowing it to cool to room temperature.

Next, extrusion processing as shown in FIG. 1 was carried out using a lubricant at a temperature of 720 tl. In Fig. 1, the outer diameter of the container part of the die is 40 mm, the inner diameter is 30 mm, and the outer diameter of the bearing part is 30 mm, and the inner diameter is 20 mm.
．． 8 and X is 20 yes. After extrusion, the billet has an outer diameter of 30#, an inner diameter of 20.8 VN, and a length of 3
It was bright. Next, the outer peripheral surface of the cylindrical billet was restrained using a mold as shown in Fig. 3 through a lubricant, and the inner periphery was left free.
The cylindrical billet was compressed up to 20 lengths at a temperature of .degree. In addition, in FIG. 3, the inner diameter of the outer mold 9 is 30 mm.

This compressed billet has an outer diameter of 29 blocks.

Inner diameter 181. A cylindrical magnet with a length of 20M was radially magnetized with 12 poles as shown in FIG. 5 from the outer circumferential surface and the inner circumferential surface. FIG. 5 schematically shows the formation of a magnetic path (indicated by a broken line in the figure) inside the cylindrical magnet when the cylindrical magnet is magnetized with multiple poles in the radial direction. As shown in FIG. 5, the magnetic path is substantially along the radial direction of the magnet. Magnetization is 2000.
Pulse magnetization was performed at 160 ov using an IIF oil condenser. The surface magnetic flux density on the outer peripheral surface was measured using a Hall element. For comparison, Mn, AI, C, and Ni having the same composition as described above were melted and cast to a diameter of 60 m.
A cylindrical billet with a length of 20 m and a length of 20 mm was prepared.

After holding this billet at 1100° C. for 2 hours, it was heat-treated by being allowed to cool to room temperature. Next, through the lubricant, 72
Conventional extrusion processes up to 40 mg diameter were carried out at a temperature of 0°C. This extruded rod was cut to a length of 30 yr and machined to have an outer diameter of 30 mm, an inner diameter of 20.8-9, and a length of 30 yr.
A cylindrical billet of m was produced.

Next, this billet was subjected to the same compression process as described above, and was further cut into a cylindrical shape in the same manner as above, magnetized, and the surface magnetic flux density was measured.

Comparing the above two values, the value of the surface magnetic flux density of the magnet obtained by the method of the present invention was about 1.2 times that of the magnet produced for comparison.

Furthermore, only the outer peripheral portion of the billet was compressed using a mold as shown in FIG. 4 at a temperature of 680° C. using the magnet that had just been magnetized according to the present invention. The diameter of punch 1o (punch 1
1) is 24 mm.

The length of the outer periphery after compression processing was 15 mm. The processed billet was machined to an outer diameter of 29 am and magnetized in the same manner as above, and when comparing the surface magnetic flux density values before and after this local compression processing, the value after processing was 0.2 kG. It got expensive.

Example 4 Mn, AI, C, and Ni having the same composition as in Example 1 were melted and cast to produce a cylindrical billet with a diameter of 50 mm and a length of 20 mm. This billet was held at 1100° C. for 2 hours, and then heat treated to cool to room temperature. Next, known extrusion processing was performed at a temperature of 720° C. to a diameter of 30 B using a lubricant. The extruded rod was cut to a length of 2ofl and machined to an outer diameter of 30 mx+.

A cylindrical billet (billet A) with an inner diameter of 10 mm and a length of 20 mg was prepared. In addition, we cut the extruded rod into lengths of 20 mm and cut them into cylindrical billets with a diameter of 29 m and a length of 40 m+ (
It was made into billet B). Billet B via lubricant, 6
The billet was subjected to free compression in the axial direction at a temperature of 60°C. The length of the fillet 7 after processing was 20 mm. After this processing, the billet (planar anisotropic magnet) was cut in the same manner as Pyrene A to obtain an outer diameter of 30 m, an inner diameter of 10 mm,
A cylindrical billet (billet B) with a length of 20+151 was made. Next, in the same manner as in Example 1, extrusion was performed using pyrene A and billet B through a lubricant at a temperature of 720° C. using a die as shown in FIG. In FIG. 1, the outer diameter of the container part of the die is 30W, the inner diameter is 10, and the outer diameter of the bearing part is 40 m.

The inner diameter is 35 mm, and the X diameter is 20 mm. After extrusion, the billet has an outer diameter of 40 mm, an inner diameter of 35 mm, and a length of 4 mm.
It was 27 mm. Next, these cylindrical billets were molded into cylinders at a temperature of 680°C using a lubricant and the outer circumferential surface of the cylindrical billets was constrained using a mold as shown in Figure 3, while the inner circumference was left free. billet length 20 tra
Compression processing was performed up to n. In addition, in Fig. 3, the outer mold 9
The inner diameter is between 40mm and 40mm.

Each billet subjected to this compression process has an outer diameter of 38 mm.
A cylindrical magnet with an inner diameter of 29 mm and a length of 20 m was magnetized with 30 poles on its outer circumferential surface. Pulse magnetization was performed at 150 oV using an oil capacitor with a magnetization value of 12,000 μF. The surface magnetic flux density of the outer peripheral surface was measured using a Hall element, and Example 1
compared with the magnet obtained in

Comparing the values of both of the above (the magnet of the present invention using billet A and billet B and the magnet obtained in Example 1), the value of the surface magnetic flux density of the magnet obtained in Example 4 is the same as that of Example 1. The billet of the produced magnet was about 1.2 times that of the magnet using billet 7) A, and about 1.3 times that of the magnet using billet B.

Furthermore, only the outer peripheral portion of the billet was compressed using a mold as shown in FIG. 4 at a temperature of 680° C. for each of the magnets of the present invention that had just been magnetized.

The diameter of the punch 10 (inner diameter of the punch 11) is 34 mm. The length of the outer peripheral portion after compression processing was 15 mm. The processed billet was machined and magnetized in the same manner as above with an outer diameter of 38mm, and when the surface magnetic flux density values were compared before and after this local compression processing, it was found that the surface magnetic flux density after processing was better. The compositions of the Mn-A I-C magnetic alloys are shown only for the quaternary system with Ni addition and the quinary system with Ni and Ti additions. Plastic processing (
Although a slight difference was observed in the magnetic properties of the magnets after extrusion processing + compression processing, the above-mentioned improvement in magnetic properties was observed compared to the known extrusion method.

Regarding local compression processing, only the method of compressing only the outer periphery of the billet was shown, but even when only the inner periphery was compressed, the magnetic properties were similarly improved.

Effects of the Invention As described in the examples, the present invention provides Mn-Al~
A hollow billet made of C-based magnetic alloy is extruded in the axial direction of the billet using a die in which the cross-sectional shape of the hollow part of the container part is hollow and the opening area of the container part is larger than the opening area of the bearing part. After extrusion processing is performed with the directions parallel to each other, and tensile strain is applied to the billet in the extrusion direction by the extrusion processing, the outer periphery of the billet is restrained, and at least a part of the inner periphery is free. By compressing the billet in the axial direction, a magnet that exhibits high magnetic properties when multipolar magnetized is obtained.

By this method, that is, by performing the above-mentioned specific extrusion processing and then performing the above-mentioned specific compression processing, the total Even if the amount of plastic working is small, a magnet that exhibits excellent magnetic properties when magnetized with multiple poles can be obtained.

[Brief explanation of the drawing]

1A and 1B are cross-sectional views of a part of a mold showing an example of the extrusion process of the present invention, FIGS. 2A to 2D are cross-sectional views of a part of a mold showing an example of the extrusion method of the present invention, Figure 3 a, l) and Figure 4 a
, b is a cross-sectional view of a part of a mold showing an example of the compression processing of the present invention, and FIG. It is a figure shown typically. 1.1'...Billet, 2...Mandrel, 3...Dice, 4,5...Punch, e...Container part , 7... Bearing part, 8... Conical part, 9... Outer mold, 1Q... Fixing punch, 11...
Movable punch, 12...Lower mold. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 5
Figure S

Claims (2)

[Claims] (1) A hollow billet made of manganese-aluminum-carbon-based magnet alloy is heated at a temperature of 530 to 830°C.
The cross-sectional shape of the hollow part of the container part is hollow, and the extrusion process is performed using a die in which the opening area of the container part is larger than the opening area of the bearing part, with the axial direction of the billet parallel to the extrusion direction, and After applying tensile strain to the billet in the extrusion direction through processing, compression processing is further performed in the axial direction of the billet while the outer periphery of the billet is restrained and at least a part of the inner periphery is free. A method for manufacturing a manganese-aluminum-carbon alloy magnet. (2) At a temperature of 530 to 830°C, a hollow billet made of a manganese-aluminum-carbon magnet alloy is
The cross-sectional shape of the hollow part of the container part is hollow, and the extrusion process is performed using a die in which the opening area of the container part is larger than the opening area of the bearing part, with the axial direction of the billet parallel to the extrusion direction, and After applying tensile strain to the billet in the extrusion direction through processing, further compressing the billet in the axial direction while constraining the outer periphery of the billet and leaving at least a portion of the inner periphery free,
A method for producing a manganese-aluminum-carbon alloy magnet, further comprising compressing a portion of the billet in the axial direction of the billet.