JPH0639668B2 - Method for producing manganese-aluminum-carbon alloy magnet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a permanent magnet. More specifically, the present invention relates to a method for producing a polycrystalline manganese-aluminum-carbon system (Mn-Al-C system) alloy magnet, and particularly to a method for producing a Mn-Al-C system alloy magnet for multipolar magnetization. is there.

2. Description of the Related Art Mn-Al-C based magnet alloys are a general term for Mn-Al-C based magnet alloys and Mn-Al-C based alloy magnets. The Mn-Al-C magnet alloy is 68 to 73 mass%.
(Hereinafter simply expressed as%) Mn and (1/10 Mn-6.
6) to (1 / 3Mn-22.2)% of C and the balance of Al, and a ternary system alloy containing no additional element other than impurities and a quaternary or more multicomponent magnet alloy containing a small amount of additional element Are known and are generic terms. Similarly, M
n-Al-C alloy magnet is composed of mainly face-centered tetragonal (tau phase, L1 ₀ type ordered lattice) is a ferromagnetic phase of tissue are those containing C as essential constituent elements, in addition to impurities A ternary system magnet containing no additional element and a quaternary or more multi-component alloy magnet containing a small amount of additional element are known, and they are collectively referred to.

Further, as a method for producing this Mn-Al-C alloy magnet, a method including a warm plastic working step such as warm extrusion processing is known in addition to the method by casting and heat treatment. In particular, the latter is known as a method for producing an anisotropic magnet having excellent properties such as high magnetic properties, mechanical strength, weather resistance and machinability.

As a method for producing the Mn-Al-C alloy magnet for multipolar magnetization, an isotropic magnet, a compression processing method, or a uniaxially anisotropic polycrystalline Mn obtained by a known method such as warm extrusion processing in advance.
-Al-C alloy magnet by free warm compression in the anisotropic direction (Japanese Patent Laid-Open No. 56-119762), and a hollow billet shaft made of Mn-Al-C magnet alloy. Various plastic workings that give compressive strain in the direction are known (for example, JP-A-58-181854 and JP-A-58-192304).

Problems to be Solved by the Invention Various types of plastic working that give a compressive strain in the axial direction of the hollow billet made of the Mn-Al-C based magnet alloy described above (especially JP-A-58-181854). )
In other words, that is, polycrystalline Mn-Al that has been anisotropy beforehand
-The hollow billet made of C-based alloy magnet has a conical portion that has a cross-sectional area perpendicular to the axial direction of the billet smaller than the opening area of the bearing portion and the opening area gradually decreases from the container portion to the bearing portion. A method of performing extrusion processing by making the axial direction of the billet parallel to the extrusion direction using a die, and further applying compression strain in the extrusion direction of the billet by the extrusion process (in order to give compression strain in the extrusion direction, this plastic processing Therefore, in the present specification, the known extrusion process is distinguished by being expressed as extrusion process A, and the extrusion process that gives a compressive strain in the above-described extrusion direction is expressed as extrusion process B or compression process). For example, a hollow body-shaped billet made of a uniaxially anisotropic polycrystalline Mn-Al-C alloy magnet obtained by a known method such as extrusion processing (extrusion processing A) is used. . By subjecting the billet to the above-mentioned specific extrusion process (extrusion process B), a magnet exhibiting excellent magnetic characteristics when multipolarized is obtained. However, the above-mentioned method requires at least two types of plastic working, that is, the known extrusion process (extrusion process A) and the above-mentioned specific extrusion process (extrusion process B).
The subsequent billet has an easy magnetization direction in the extruding direction, and has a magnetic anisotropy structure converted into a magnet exhibiting excellent magnetic properties when multipolarized by the specific extrusion process B described above. There is. That is, the billet after the known extrusion processing A has a uniaxial anisotropy having an easy magnetization direction in the axial direction of the billet, has an anisotropic structure not suitable for multi-pole magnetization, and has the following plastic processing (extrusion processing B ), The magnetic properties in the radial direction and the circumferential direction are improved, and the structure having magnetic anisotropy is converted into a magnet exhibiting excellent magnetic properties when magnetized in multiple poles.

In the above-mentioned method, it is excellent when the uniaxial anisotropic magnet (anisotropic magnet not suitable for multi-pole magnetization) is once formed by extrusion processing A and then multi-pole magnetized by the next plastic processing (extrusion processing B). Since the structure is changed to a magnet exhibiting magnetic characteristics, it is a wasteful manufacturing method in terms of magnetic characteristics.

The present invention aims to obtain excellent magnetic properties with a small amount of processing.

In order to achieve this object, the present invention provides manganese-
A hollow body-shaped billet made of an aluminum-carbon magnet alloy has a hollow cross-sectional shape of the hollow portion of the first container portion at a temperature of 530 to 830 ° C., and the opening area of the first container portion is the first. Using a first die larger than the opening area of the first bearing portion, a first extrusion process is performed by making the axial direction of the billet parallel to the extrusion direction, and the hollow body-shaped billet is obtained by this first extrusion process. After being expanded in the axial direction and the circumferential direction, the expanded hollow body billet is further decreased in the opening area from the second container portion to the second
The second die having a conical portion extending to the bearing portion is subjected to a second extrusion process in which the axial direction of the billet and the extrusion direction are parallel to each other, and the second extrusion process causes the billet to move in the axial direction. It compresses in the circumferential direction.

After performing the known extrusion process (extrusion process A) by the above-described method, that is, after performing the specific extrusion process described above, and then performing the specific extrusion process (extrusion process B) , The specific extrusion process described above (Extrusion process B)
Even if the total amount of plastic working is smaller than that of the method described above, a magnet exhibiting excellent magnetic characteristics can be obtained when magnetized in multiple poles.

Example In the present invention, a hollow-body-shaped billet made of a manganese-aluminum-carbon magnet alloy has a hollow cross-sectional shape of the hollow portion of the first container portion at a temperature of 530 to 830 ° C. Using the first die, the opening area of the container part of which is larger than the opening area of the first bearing part, the first extrusion process is performed by making the extrusion direction parallel to the axial direction of the billet, and the first extrusion process is performed. After extending the hollow body billet in the axial direction and the circumferential direction by the above, the expanded hollow body billet further decreases in opening area from the second container portion to the second bearing portion. A second die having a conical portion is used to perform a second extrusion process in which the billet axial direction and the extrusion direction are parallel to each other, and the billet is compressed in the axial direction and the circumferential direction by the second extrusion process. thing Is.

The second extrusion process (extrusion process) described above is performed by the method of obtaining the Mn-Al-C alloy magnet that has been previously anisotropy by the known extrusion process (extrusion process A) by performing the above-described extrusion process. A magnet exhibiting excellent magnetic properties can be obtained when multipolar magnetization is performed even if the strain amount in the processing B) is small.

The above-mentioned two extrusion processes do not necessarily have to be continuous plastic processes, and may be given by dividing into a plurality of times.

An example of the first (first) extrusion process of the present invention described above will be described with reference to FIG. 1 in which the billet has a cylindrical shape. FIG. 1 (a) is a sectional view of a part of the die showing a state before extrusion, and similarly FIG. 1 (b) shows a 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 dice 3 form a dice. In FIG. 1, 6
Is a container portion, which is a portion that accommodates the billet 1 before extrusion, and 7 is a bearing portion, which is a portion that accommodates the billet 1 after extrusion. 8 is a conical part.
The opening area of the container portion 6 is the cross-sectional area of the cavity of the container portion 6 (perpendicular to the extrusion direction), which is almost the same as the cross-sectional area of the billet 1 in FIG. Is the cross-sectional area of the cavity of the bearing portion 7 (perpendicular to the extrusion direction), which is substantially the same as the cross-sectional area of the billet 1 in FIG. 1 (b).

In FIG. 1, since both the container portion 6 and the bearing portion 7 are circular with the extruding shaft as the center, in other words, the opening area of the container portion 6 is a ring shape defined by the outer diameter and the inner diameter of the container portion 6. Area. The cross-sectional shape of the hollow portion of the container portion 6 is the above-mentioned ring shape and is hollow. Similarly, the opening area of the bearing portion 7 is a ring-shaped area formed by the outer diameter and the inner diameter of the bearing portion 7. For example, the outer diameter of the container portion 6 is 40 mm, the inner diameter is 20 mm,
When the outer diameter of the bearing portion 7 is 50 mm and the inner diameter is 40 mm, the opening area of the container portion 6 is about 942 mm ² , and the opening area of the bearing portion 7 is about 707 mm ² . The cross-sectional shape of the hollow portion of the container portion 6 is a ring shape having an outer diameter of 40 mm and an inner diameter of 20 mm. In other words, the hollow portion of the container portion 6 has a hollow cross-sectional shape when the billet 1 is housed in the container portion 6 as shown in FIG. That is, there is a die constituent member (mandrel 2) in the central portion, a billet 1 is further outside thereof, and a die constituent member (die 3) is further outside thereof.

An example of the extrusion processing method will be described with reference to FIG. First, as shown in FIG. 2 (a), the cylindrical billet 1 '
To house. By pressing the billet 1'using the punch 4, it becomes as shown in FIG. 2 (b). Next, Fig. 2 (c)
As shown in FIG. 2, the billet 1 is newly accommodated in the container portion 6, and the billet 1 is pressurized by using the punch 4 in the same manner as described above, so that the state shown in FIG. Thereafter, extrusion processing is performed by repeating this.

As another extrusion processing method, in the state shown in FIG. 2 (c), the billet 1 is moved in the direction from the container part 6 to the bearing part 7 while pressing the billet 1 with the punches 4 and 5 (second part). In the figure, the state of the billet 1 is shown in FIG.
There is a method of performing extrusion processing by moving from (c) to FIG. 2 (d)).

In FIG. 2 (a), the shape of the cylindrical billet 1'has a shape with an appropriate clearance so that the cylindrical billet 1'can be easily inserted into the container portion 6, but the cross section of the cylindrical billet 1 '( Plane perpendicular to the axial direction) and container part 6
The cross-sectional shapes of the hollow portions (the shape of the hollow portions when the die is cut along a plane perpendicular to the extrusion direction) are both ring-shaped.

The compression processing (extrusion processing B) in the next step and the method of giving a compressive strain to a part of the billet 1 in the axial direction of the billet 1 are described in the above-mentioned known art (Japanese Patent Laid-Open No. 58-18).
1854).

Regarding the temperature range in which plastic working as described above is possible,
Machining could be performed in the temperature range of 530 to 830 ° C, but the magnetic properties were considerably deteriorated at a temperature exceeding 780 ° C. A more desirable temperature range is 560 to 760 ° C.
Met.

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

Example 1 In the composition, 69.5% Mn, 29.3% Al, 0.
5% C and 0.7% Ni are melt-cast and the outer diameter is 25 m
A cylindrical billet having an m, an inner diameter of 5 mm and a length of 20 mm was produced.
After holding this billet at 1100 ° C for 2 hours, 600
After air-cooling to 600 ° C. and holding at 600 ° C. for 30 minutes, a heat treatment of allowing to cool to room temperature was performed.

Next, extrusion processing as shown in FIG. 1 was performed at a temperature of 720 ° C. through a lubricant. In FIG. 1, the outer diameter of the container portion of the die is 25 mm, the inner diameter is 5 mm, the outer diameter of the bearing portion is 30 mm, the inner diameter is 25 mm, and X is 20 mm. The billet after extrusion has an outer diameter of 30 mm and an inner diameter of 25 m.
It was m and the length was 43.6 mm. The billet after processing was cut into a length of 20 mm. Then, through the lubricant, the third
The inner cylinder billet was processed at a temperature of 680 ° C. using the mold shown in the figure. In FIG. 3, the names of the parts are almost the first.
It is the same as the figure. The difference from FIG. 1 is the presence or absence of the mandrel 2 and the punch 5. That is, the mold shown in FIG. 3 does not have the mandrel 2 and the punch 5. Further, as described above, in the plastic working using the mold shown in FIG. 1, it can be said that the billet is extruded because the axial length of the billet is elongated by the working, but the mold shown in FIG. 3 was used. In plastic working, the length of the billet in the axial direction shrinks due to working, so it can be said to be compression working. In FIG. 3, the diameter of the container part is 30 mm, the diameter of the bearing part is 28 mm,
α is 10 °. The dimension of the cylindrical billet after processing was 28 mm in outer diameter, 19 mm in inner diameter, and 13 mm in length.

The billet after processing has an outer diameter of 27 mm, an inner diameter of 20 mm and a length of 13
A cylindrical billet of mm was cut, and 12 poles were radially magnetized from the outer peripheral surface and the inner peripheral surface as shown in FIG. FIG. 4 schematically shows the formation of a magnetic path (indicated by a broken line in the drawing) inside the magnet when the cylindrical magnet is magnetized in multiple radial directions. As shown in FIG. 4, the magnetic path is substantially along the radial direction of the magnet. The magnetization was pulse-magnetized at 1500 V using a 2000 μF oil condenser. The surface magnetic flux density on the outer peripheral surface was measured with a Hall element.

For comparison, M of the same composition as the composition described above
n, Al, C and Ni were melted and cast to form a cylindrical billet having a diameter of 50 mm and a length of 20 mm. This billet is 11
After holding at 00 ° C. for 2 hours, a heat treatment of cooling to room temperature was performed. Then, a known extrusion process up to a diameter of 30 mm was performed at a temperature of 720 ° C. through a lubricant. This extruded rod is cut into a length of 20 mm and cut to have an outer diameter of 30 mm and an inner diameter of 2
A cylindrical billet having a length of 5 mm and a length of 20 mm was produced. Next, this billet was subjected to the same plastic working as the plastic working using the mold shown in FIG. 3, 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.

Further, only the outer peripheral portion of the billet was compression-processed at a temperature of 680 ° C. by using the magnet directly magnetized as described above according to the present invention using a mold as shown in FIG. In Fig. 5, Fig. 5 (a)
Shows the state before processing, and FIG. 5 (b) shows the state after processing. Reference numeral 9 is a lower die, 10 is a fixed punch, and 11 is a movable punch. The billet 1 is fixed and constrained by the lower die 9 and the fixing punch 10, and only the outer peripheral portion of the billet is compressed by pressing the billet 1 with the movable punch 11. The diameter of the punch 10 (punch 11
Inner diameter) is 23 mm. The outer peripheral length after compression processing was 10 mm. The billet after processing was cut, magnetized in the same manner as above with an outer diameter of 27 mm, and the surface magnetic flux densities before and after this local compression processing were compared. 2kG higher.

Example 2 69.4% of Mn, 29.3% of Al, and 0.
5% C, 0.7% Ni and 0.1% Ti were melted and cast to prepare a cylindrical billet having an outer diameter of 20 mm, an inner diameter of 5 mm and a length of 20 mm. The billet was held at 1100 ° C. for 2 hours, then air-cooled to 600 ° C., held at 600 ° C. for 30 minutes, and then heat-treated to cool to room temperature. Next, extrusion processing as shown in FIG. 1 was performed at a temperature of 720 ° C. through a lubricant. In FIG. 1, the outer diameter of the container portion of the die is 20 mm, the inner diameter is 5 mm, the outer diameter of the bearing portion is 30 mm, the inner diameter is 26 mm, and X is 20 mm. The extruded billet has an outer diameter of 30 mm, an inner diameter of 26 mm, and a length of 3
It was 3.5 mm. Next, the cylindrical billet was compressed in the axial direction of the cylindrical billet at a temperature of 680 ° C. through a lubricant using a mold as shown in FIG. In FIG. 3, the outer diameter of the container portion of the die is 30 mm, the diameter of the bearing portion is 28 mm, and α is 10 °. The processed cylindrical billet had an outer diameter of 28 mm, an inner diameter of 18 mm and a length of 10 mm.

The billet that has been subjected to this compression processing has an outer diameter of 27 mm and an inner diameter of 19
As a cylindrical magnet having a length of 10 mm and a length of 10 mm, 1
8 poles were radially magnetized. The magnetization was pulse-magnetized at 1500 V using a 2000 μF oil condenser. The surface magnetic flux density on the outer peripheral surface was measured with a Hall element. For comparison, Mn and A having the same composition as the composition described above are used.
1, C, Ni and Ti were melted and cast to form a cylindrical billet having a diameter of 50 mm and a length of 20 mm. This billet is 11
After holding at 00 ° C. for 2 hours, a heat treatment of cooling to room temperature was performed. Then, a known extrusion process up to a diameter of 30 mm was performed at a temperature of 720 ° C. through a lubricant. This extruded rod was cut into a length of 20 mm and cut to produce a cylindrical billet having an outer diameter of 30 mm, an inner diameter of 26 mm and a length of 20 mm. Next, this billet is subjected to the same compression processing as described above,
Further, similarly to the above, it was cut into a cylindrical shape, 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.

Further, the magnet magnetized previously according to the present invention was compression-processed only at the outer peripheral portion of the billet at a temperature of 680 ° C. using a mold as shown in FIG. The diameter of the punch 10 (the inner diameter of the punch 11) is 22 mm. The outer peripheral length after compression processing was 7 mm. The billet after processing was cut, magnetized in the same manner as above with an outer diameter of 27 mm, and the surface magnetic flux densities before and after this local compression processing were compared. 2kG higher.

Example 3 Mn, Al, C and Ni having the same compounding composition as in Example 1 were melt-cast and a cylindrical billet having an outer diameter of 40 mm, an inner diameter of 30 mm and a length of 20 mm was produced. The billet was held at 1100 ° C. for 2 hours, then air-cooled to 600 ° C., held at 600 ° C. for 30 minutes, and then heat-treated to cool to room temperature.

Next, extrusion processing as shown in FIG. 1 was performed at a temperature of 720 ° C. through a lubricant. In Fig. 1, the outer diameter of the container portion of the die is 40 mm and the inner diameter is 30 mm, the outer diameter of the bearing portion is 30 mm and the inner diameter is 20.8 mm, and X is 2
It is 0 mm. The billet after extrusion had an outer diameter of 30 mm, an inner diameter of 20.8 mm, and a length of 30 mm. Next, this cylindrical billet was compressed in the axial direction of the billet at a temperature of 680 ° C. through a lubricant using a mold as shown in FIG. In Fig. 3, the diameter of the container part of the die is 30 mm and the diameter of the bearing part is 28 mm.
Is 10 °. The billet after compression processing has an outer diameter of 28 mm,
The inner diameter was 10 mm and the length was 20.5 mm.

This compressed billet has an outer diameter of 27 mm and an inner diameter of 11
As a cylindrical magnet having a length of 20 mm and a length of 20 mm, 12 poles were radially magnetized. The magnetization was pulse-magnetized at 1500 V using a 2000 μF oil condenser. The surface magnetic flux density on the outer peripheral surface was measured with a Hall element. For comparison, Mn, Al, C, and Ni having the same composition as the composition described above were melt-cast and a cylindrical billet having a diameter of 50 mm and a length of 20 mm was produced. The billet was held at 1100 ° C. for 2 hours and then heat-treated by allowing it to cool to room temperature. Then, a known extrusion process up to a diameter of 30 mm was performed at a temperature of 720 ° C. through a lubricant. This extruded rod was cut into a length of 30 mm and cut to produce a cylindrical billet having an outer diameter of 30 mm, an inner diameter of 20.8 mm and a length of 30 mm. Next, this billet was subjected to the same compression processing as the above-mentioned compression processing, and was further cut into a cylindrical shape in the same manner as described 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 1.3 times that of the magnet prepared for comparison.

Example 4 Mn, Al, C and Ni having the same compounding composition as in Example 1 were melt-cast and a cylindrical billet having a diameter of 50 mm and a length of 20 mm was produced. The billet was held at 1100 ° C. for 2 hours and then heat-treated by allowing it to cool to room temperature.

Then, a known extrusion process up to a diameter of 25 mm was performed at a temperature of 720 ° C. through a lubricant. The extruded rod is cut to a length of 20 mm, and is cut and processed to have an outer diameter of 25 mm, an inner diameter of 5 mm, and a length of 20 mm.
To a cylindrical billet (billet A). Further, the extruded rod was cut into a length of 20 mm and cut into a cylindrical billet (billet B) having a diameter of 25 mm and a length of 35 mm. Using this billet B, through a lubricant, at a temperature of 660 ° C.,
Free compression processing was performed in the axial direction of the billet. The length of the billet after processing was 20 mm. The billet (plane anisotropic magnet) after this processing was cut into a cylindrical billet (billet B) having an outer diameter of 25 mm, an inner diameter of 5 mm and a length of 20 mm, similarly to the billet A. Next, the same extrusion processing and compression processing as in Example 1 were performed. That is, the billet A and the billet B were extruded through a lubricant at a temperature of 680 ° C. using a die as shown in FIG. In FIG. 1, the outer diameter of the container portion of the die is 25 mm and the inner diameter is 5 mm, the outer diameter of the bearing portion is 30 mm, the inner diameter is 25 mm, and X is 20 mm. Billet after extrusion has an outer diameter of 3
The length was 0 mm, the inner diameter was 25 mm, and the length was 43.6 mm. Next, this billet was cut into a length of 20 mm, and these cylindrical billets were compression processed in the axial direction of the cylindrical billet at a temperature of 680 ° C. through a lubricant using the mold shown in FIG. .
In FIG. 3, the diameter of the container portion of the die is 30 mm, the diameter of the bearing portion is 28 mm, and α is 10 °. The billet after processing has an outer diameter of 28 mm, an inner diameter of 19 mm,
It was 13 mm in length.

The billets thus processed were each made into a cylindrical billet having an outer diameter of 27 mm, an inner diameter of 20 mm and a length of 13 mm, and 12 poles were radially magnetized. The magnetization was pulse-magnetized at 1500 V using a 2000 μF oil condenser. The surface magnetic flux density on the outer peripheral surface was measured with a Hall element and compared with the magnet of the present invention obtained in Example 1.

Comparing the values of the following two (the magnet of the present invention using billet A and billet B and the magnet of the present invention obtained in Example 1), the value of the surface magnetic flux density of the magnet obtained in Example 4 was The magnet produced by using the billet A of the magnet produced in Example 1 was about 1.2 times, and the magnet produced by the billet B was about 1.3 times.

As described above, regarding the composition of the Mn-Al-C based magnet alloy, N
Only the i-added quaternary system and the Ni- and Ti-added quinary system are shown. However, a known ternary system which is a basic composition of the Mn-Al-C alloy magnet or a known additive element other than the above Regarding the multi-component system, although a slight difference was found in the magnetic properties of the magnet after plastic working, the improvement in magnetic properties as described above was recognized by the known extrusion method.

As for the local compression processing, only the method of compressing only the outer peripheral portion of the billet is shown, but even when only the inner peripheral portion of the billet is compressed, the improvement of the magnetic characteristics is similarly recognized.

EFFECTS OF THE INVENTION As described in the examples, the present invention provides a hollow body-shaped billet made of a manganese-aluminum-carbon magnet alloy, at a temperature of 530 to 830 ° C., and having a cross section of the hollow portion of the first container portion. Using a first die having a hollow shape and having an opening area of the first container portion larger than that of the first bearing portion, the first extrusion process is performed with the billet axial direction and the extrusion direction parallel to each other. And the hollow body-shaped billet is expanded in the axial direction and the circumferential direction by the first extrusion process, and then the expanded hollow body-shaped billet is sequentially opened from the second container portion. Second decrease
The second die having a conical portion extending to the bearing portion is subjected to a second extrusion process in which the axial direction of the billet and the extrusion direction are parallel to each other, and the second extrusion process causes the billet to move in the axial direction. By compressing in the circumferential direction,
A magnet exhibiting excellent magnetic characteristics can be obtained even when the total amount of plastic working is smaller than that of the above-described specific compression working after performing the known publicly known extrusion processing when multi-pole magnetized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A and FIG. 1B are partial sectional views of a mold showing an example of extrusion processing of the present invention, and FIGS. 2A to 2D are molds showing an example of extrusion method of the present invention. 3a and 3b are partial sectional views of a mold showing an example of the compression processing of the present invention, and FIG. 4 is a multi-pole magnetized in the radial direction of a cylindrical magnet. 5A and 5B are schematic cross-sectional views of a mold showing an example of the compression processing of the present invention. 1, 1 '... Billet, 2 ... Mandrel, 3 ... Die, 4, 5 ... Punch, 6 ... Container part, 7 ... Bearing part, 8 ... Conical part, 9 ... Lower mold, 10 ... fixed punch, 11 ... movable punch.

Claims (2)

[Claims] 1. A hollow body-shaped billet made of a manganese-aluminum-carbon magnet alloy has a hollow cross-sectional shape of a hollow portion of a first container portion at a temperature of 530 to 830 ° C. Using the first die in which the opening area of the container part is larger than the opening area of the first bearing part, the first extrusion process is performed by making the axial direction of the billet parallel to the extrusion direction, and the first extrusion process is performed. After the hollow body-shaped billet is expanded in the axial direction and the circumferential direction, the expanded hollow body-shaped billet further decreases in opening area from the second container portion to the second bearing portion. A second die having a portion is used to perform a second extrusion process in which the axial direction of the billet and the extrusion direction are parallel to each other.
The method for producing a manganese-aluminum-carbon alloy magnet, comprising compressing the billet in the axial direction and the circumferential direction by the extrusion process of 1. 2. A hollow body-shaped billet made of a manganese-aluminum-carbon magnet alloy has a hollow sectional shape of a hollow portion of a first container portion at a temperature of 530 to 830 ° C. Using the first die in which the opening area of the container part is larger than the opening area of the first bearing part, the first extrusion process is performed by making the axial direction of the billet parallel to the extrusion direction, and the first extrusion process is performed. After the hollow body-shaped billet is expanded in the axial direction and the circumferential direction, the expanded hollow body-shaped billet further decreases in opening area from the second container portion to the second bearing portion. A second die having a portion is used to perform a second extrusion process in which the axial direction of the billet and the extrusion direction are parallel to each other.
Manganese-characterized in that the billet is compressed in the axial direction and the circumferential direction by extrusion processing, and then a part of the compressed billet is compressed in the axial direction of the billet.
A method for manufacturing an aluminum-carbon alloy magnet.