JPH0663075B2 - Method for producing manganese-aluminum-carbon alloy magnet - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a permanent magnet, and more particularly, to a high-performance multi-pole magnetized with a polycrystalline manganese-aluminum-carbon (Mn-Al-C) alloy magnet. For manufacturing Mn-Al-C alloy magnet for use in automobiles.

2. Description of the Related Art Mn-Al-C alloy magnets are mainly composed of a face-centered tetragonal crystal (τ phase, L1o type ordered lattice), which is a ferromagnetic phase.
Is included as an essential constituent element, and a ternary alloy magnet containing no additional element other than impurities and a quaternary or more multi-component alloy magnet containing a small amount of additional element are known, and these are collectively referred to. .

Conventionally, the manufacturing method is such that the outer periphery of a hollow body billet made of an alloy for Mn-Al-C magnets is constrained by an outer mold,
A punch having a flat compression surface was used for compression processing (Japanese Patent Laid-Open No. 192306/58).

Problems to be Solved by the Invention According to the above-described conventional manufacturing method, the billet is subjected to substantially the same compressive strain at both the inner and outer peripheral portions thereof. It becomes a substantially straight line in the radial direction like the line A.

Therefore, in this state, even if S and N are magnetized on the outer circumference or the inner circumference as shown in the figure, the ideal semi-circular B line which is the ideal easy magnetization direction array is too much. Since the arrangement of the easy magnetization direction is different, a strong magnetic force could not be obtained even when the magnetizing work was performed.

Therefore, in the above-mentioned conventional example, as shown in FIG.
Before magnetizing N, the inner peripheral portion of the compressed billet is compressed again to bring the easy magnetization direction array to a substantially semicircular shape as shown in FIG. 7 of the present application, and thereafter magnetizing the inner periphery. I was trying to do the work.

However, in the conventional case, in order to obtain such a substantially semi-circular easy direction alignment, the inner circumference or the outer circumference of the billet must be compressed again after the compression of the billet, resulting in poor workability. It was

In view of this, the present invention, in which S, N is magnetized on the outer peripheral portion of the billet, makes it possible to easily obtain a substantially semicircular easy magnetization direction direction, and to integrate another billet in the billet. It is intended to be

Means for Solving the Problems And, in order to achieve this object, the present invention provides a hollow portion of a hollow first billet made of a pre-anisotropic polycrystalline manganese-aluminum-carbon alloy magnet. In the state where the second billet made of a metal material is present, at a temperature of 530 to 830 ° C., the punch is configured to axially compress these first and second billets, and the compression surface of the punch is The first and second billets have an inclination approaching the ends of the first and second billets from the inner circumference toward the outer circumference, and the inclined compression surface of the punch compresses the outer circumference of the hollow first billet. With the strain being larger than the compressive strain of the inner peripheral portion, the hollow body-shaped first billet is formed until the inner peripheral surface of the first billet and the outer peripheral surface of the second billet come into contact with each other or more. , Also axially compressed It is.

With the above configuration, the first billet is formed with the second billet made of a metal material provided in the hollow portion of the hollow first billet made of a manganese-aluminum-carbon magnet alloy. When the is compressed axially by the punch, the compression surface of the punch moves from the inner circumference toward the outer circumference to the first
Since the first billet has a slope approaching the end of the second billet, the compressive strain of the outer periphery of the first billet is larger than the compressive strain of the inner periphery, and as a result, the outer periphery of the first billet after compression is increased. , A semi-circular easy magnetization direction array is easily formed by one-time compression.
When S and N are magnetized on the outer circumference of the billet, a strong magnetic force is obtained.

Also, due to this compression, the second billet and the first billet for performing post-processing (cutting, etc.) for attachment to other equipment are integrated, so that the manufacturing process is simplified from this point as well. Will be realized.

Example FIG. 1 shows a cross section before processing. 1 is a hollow-shaped first billet (pre-anisotropic polycrystalline Mn-Al-
Billet made of C-based alloy magnet), 2 is a rod-shaped second billet (billet made of metal material), 4 and 5 are punches,
6 is an outer type. As shown in FIG. 1, the compression surfaces 4a and 5a of the punch 4 and the punch 5 which come into contact with the first and second billets 1 and 2 are the end portions of the billets 1 and 2 from the inner peripheral portion toward the outer peripheral portion. Has a slope α approaching. By using the punch 4 and the punch 5 to press the billets 1 and 2 in the axial direction, the billets 1 and 2 are compressed in the axial direction. First
The heights of the billet 1 and the billet 2 shown in the figure before processing are the same. Therefore, the height of the outer circumference of billets 1 and 2 after processing is smaller than the height of the inner circumference, and billets 1 and 2
The billets 1 and 2 were compressed in the axial direction so that the compressive strain on the outer peripheral portion of the billet was larger than that on the inner peripheral portion. Compressive strain refers to the axial strain of billets 1 and 2.

Further, by this compression, the inner peripheral surface of the billet 1 and the outer peripheral surface of the billet 2 are pressed and integrated.

2 to 6 show another embodiment. In the embodiment shown in FIG. 2, the third billet 3 is integrated within the second billet 2.

FIG. 3 shows that the outer peripheral surface of the second billet 2 is the first billet 1.
What is in contact with the inner peripheral surface of is compressed axially by punches 4 and 5.

FIG. 4 uses a cylindrical billet as the second billet 2.

FIG. 5 shows the first and second billets 2 and 3 in the first billet 1.
Is provided and the surfaces of these three billets 1 to 3 which are opposed to each other are brought into contact with each other, and are compressed axially by the punches 4 and 5.

FIG. 6 shows the second and the third integrated in the first billet 1.
The billets 2 and 3 are provided, which is different from that shown in FIG. 2 in that the outer peripheral surface of the first billet 1 is separated from the inner peripheral surface of the outer mold 6.

That is, in each of the examples of the present invention, the hollow part of the first billet 1 having a hollow body made of an alloy for manganese-aluminum-carbon magnets is provided with the second and third billets made of a metal material.
Punch the first billet 1 with two and three punches 4,5
The first and second billets 1 are compressed in the axial direction by means of the punches 4 and 5, and the compression surfaces of the punches 4 and 5 have an inclination to approach the first billet 1 from the inner peripheral portion toward the outer peripheral portion. The compressive strain of is larger than the compressive strain of the inner circumference,
As a result of this, the outer periphery of the billet 1 after compression is
As shown by the line B in the figure, a substantially semi-circular array of easy magnetization directions is easily formed by one compression, and when S and N are magnetized on the outer periphery of the billet 1, a strong magnetic force is obtained. Of.

Also, by this compression, second and third billets for performing post-processing (cutting, etc.) for attachment to other equipment, for example.
Since the second and third billets 1 and the first billet 1 are integrated, the manufacturing process is simplified also from this point.

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

(Figure 2) 69.5% Mn, 29.3% Al, 0.5% C and 0.7
% Ni was melted and cast to form a cylindrical billet having a diameter of 50 mm and a length of 40 mm. The billet was held at 1100 ° C. for 2 hours and then heat-treated to cool to room temperature.

Next, through a lubricant, at a temperature of 720 ° C., extrusion processing with a diameter of up to 32 mm was performed.

This extruded rod is cut and cut to have an outer diameter of 30 mm and an inner diameter of 24 m.
m, cylindrical first billet 1 with length 20 mm and outer diameter 11 m
A second cylindrical billet 2 having a diameter of m, an inner diameter of 5 mm and a length of 20 mm was produced, and a brass bar (diameter: 5 m) was formed in the hollow portion of the second billet 2.
and a third billet 3 having a length of 20 mm) was inserted.
The second and third billets 2 and 3 were placed in the hollow portion of the first billet 1, and compression processing was carried out at a temperature of 680 ° C. through a lubricant based on FIG. The outer diameter 6 has an inner diameter of 30 mm and an inclination angle (α) of 10 °. The machining was performed until the cavity formed by the outer die 6, punches 4,5 and billets 1, 2, 3 was almost eliminated. After machining the billet after machining to an outer diameter of 20 mm,
It was magnetized with 12 poles and the surface magnetic flux density was measured.

For comparison, using the same first and second billets 1 and 2 as described above, compression processing was performed using a punch whose compression surface was a flat surface, and after cutting processing in the same manner as above, It was magnetized with 12 poles 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 this example was about 1.2 times that of the magnet produced for comparison.

Also, regarding the composition of the Mn-Al-C alloy magnet, only the quaternary system of Ni addition and the quinary system of Ni and Ti additions are shown, but it is the basic composition of the Mn-Al-C alloy magnet. Even in the ternary system, a slight difference was observed in the magnetic characteristics of the magnet, but the above-mentioned improvement in the magnetic characteristics was recognized in comparison with the known compression processing method.

Further, an example in which a uniaxial anisotropic magnet or a plane anisotropic magnet is used as the Mn-Al-C alloy magnet that has been anisotropy in advance is shown, but the same applies when a diameter anisotropic magnet or the like is used.

Effect of the Invention As described above, the present invention is a state in which the second billet made of a metal material is provided in the hollow part of the first billet in the form of a hollow body made of an alloy for manganese-aluminum-carbon magnets. The first billet is axially compressed by a punch, and the compression surface of the punch has a slope approaching the first and second billet ends from the inner peripheral portion toward the outer peripheral portion. The compressive strain of the outer peripheral portion of the billet is larger than the compressive strain of the inner peripheral portion, and as a result, the semi-circular easy magnetizing direction array is compressed once in the outer peripheral portion of the first billet after compression. It is easily formed, and when S and N are magnetized on the outer circumference of the first billet, a strong magnetic force can be obtained.

Also, due to this compression, the second billet and the first billet for performing post-processing (cutting, etc.) for attachment to other equipment are integrated, so that the manufacturing process is simplified from this point as well. Will be realized.

[Brief description of drawings]

1 to 6 are sectional views showing an embodiment of the present invention, and FIG. 7 is a plan view showing an arrangement in the easy magnetization direction. 1 ... 1st billet, 2, 3 ... 2nd, 3rd billet,
4,5 …… Punch, 6 …… Outer mold, α …… Inclination angle.

Claims (6)

[Claims] 1. Pre-anisotropic polycrystalline manganese-
First hollow body made of aluminum-carbon alloy magnet
The second billet made of a metal material is present in the hollow part of the billet at a temperature of 530 to 830 ° C and is compressed by a punch in the axial direction of the first and second billets. The compression surface of the punch has a slope approaching the end portions of the first and second billets from the inner peripheral portion toward the outer peripheral portion,
Due to the inclined compression surface of the punch, the inner peripheral surface of the first billet and the second inner surface of the first billet are set in a state in which the compressive strain of the outer peripheral portion of the hollow body-shaped first billet is larger than the compressive strain of the inner peripheral portion. A method for producing a manganese-aluminum-carbon alloy magnet, comprising axially compressing the hollow first billet until it contacts the outer peripheral surface of the billet or more. 2. The method for producing a manganese-aluminum-carbon alloy magnet according to claim 1, wherein at least the outer peripheral portion of the second billet made of a metal material is made of a magnetic material. 3. A hollow-body-shaped first billet is made of a polycrystalline manganese-aluminum-carbon alloy magnet having an easy magnetization direction array in the axial direction of the hollow body, and the compressive strain is an absolute value of logarithmic strain. Is 0.05 or more, The method for producing a manganese-aluminum-carbon alloy magnet according to claim 1 or 2. 4. A hollow-body-shaped first billet has an easy magnetization direction array parallel to a plane perpendicular to the axial direction of the hollow body, and is magnetically isotropic in the plane, and The manganese-aluminum-carbon according to claim 1, comprising a polycrystalline manganese-aluminum-carbon alloy magnet which is anisotropic in a plane including a straight line parallel to the axial direction and the plane. -Based alloy magnet manufacturing method. 5. The manganese according to claim 1 or 2, wherein the first hollow billet is made of a polycrystalline manganese-aluminum-carbon alloy magnet having an easy magnetization direction array in the radial direction. -Aluminum-Carbon-based alloy magnet manufacturing method. 6. A compression process using a punch is performed in a state where the outer periphery of the hollow billet is restrained by an outer mold, and at least a part of the inner periphery is free. Or the manganese of item 2
A method for manufacturing an aluminum-carbon alloy magnet.