JP3047239B2 - Warm-worked magnet and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a permanent magnet substantially consisting of a rare earth, a transition metal, and boron, and to an improvement of a warm-worked magnet imparting magnetic anisotropy by warm working. In particular, the present invention relates to a permanent magnet which improves workability by adding graphite powder and low melting point glass, has no cracks, and realizes good magnetic properties by utilizing a chemical reaction between the additive and magnetic powder.

[Prior Art] Permanent magnets (hereinafter referred to as RTB-based permanent magnets) substantially made of rare earths, transition metals and boron have attracted attention as being inexpensive and having high magnetic properties.

However, this type of magnet is roughly divided into a sintered magnet and a super-quenched magnet. Whichever manufacturing method is used, it is necessary to mold into a required shape, and moldability is important. The use of a lubricant to improve the formability has been conventionally performed. The lubricant is an external lubricant applied to the die surface or the surface of the molded object to reduce the friction coefficient between the molded object and the die surface, and the mutual friction between the powder particles constituting the molded object. Powdery, added to reduce the coefficient
It is roughly divided into internal lubricants, which are liquid and solid lubricants.

However, when trying to obtain magnetic anisotropy in a sintered magnet, a complicated step of molding in a magnetic field is essential, and the shape is restricted.

Therefore, quenching magnets that do not require molding in a magnetic field, especially R
-T-B melt is solidified by a super-quenching method, a ribbon or a flake is obtained, pulverized, hot-pressed (high-temperature treatment), and then subjected to plastic working in a warm state to impart a magnetic anisotropy ( (Hereinafter referred to as "warm-processed magnet") has been attracting attention (Japanese Patent Application Laid-Open
-100402 publication). The inside of the ribbon or flake obtained by the ultra-quenching method further comprises countless fine crystal grains. Therefore, although the ribbon or flake obtained by the ultra-quenching method has a plate-like amorphous shape with a thickness of about 30 μm and a variable length of 500 μm or less, the crystal grains contained therein are sintered magnets (for example, 1-90μm of Japanese Patent Publication No. 61-34242)
This is because it is as fine as 0.02 to 1 μm, which is close to the critical dimension of about 0.3 μm of a single magnetic domain of the magnet of this system, and essentially excellent magnetic properties can be obtained.

In a warm-worked magnet, a close correlation between the plastic flow and the magnetic arrangement in a direction perpendicular to the plastic flow is important. It is necessary to improve the degree of orientation related to the magnetic properties so that the plastic flow is uniformly and sufficiently applied to the entire workpiece. In addition, the non-uniform deformation causes a large crack at the edge due to a bulge phenomenon (a phenomenon in which the edge is deformed into a barrel shape) of the workpiece in the plastic working. This is a serious problem when trying to obtain a magnet as a product.

Here, most of the working force applied at the time of warm working is used for plastic work, but is partially wasted as friction work. This also causes the above-mentioned bulge phenomenon.

Therefore, in order to improve the workability of warm working and to obtain a crack-free warm working magnet, JP-A-60-100402 discloses that graphite is used as an external lubricant on a die surface used for warm upsetting. A lined example is described.

There is also known a method of manufacturing a warm-worked magnet using graphite and glass as a composite additive as an external lubricant (see US Pat. No. 4,780,226). In this method, a low-melting glass powder having a low melting point equal to or lower than a warm working temperature, or a mixture of the glass powder and the graphite powder is sprayed on the surfaces of a working punch and a die.

[Problems to be Solved by the Invention] In the above-described method of lining graphite and / or glass as an external lubricant on the surface of a die, the friction coefficient between a magnet body (work) and a tool (die, punch) is simply determined. Is to reduce.

Even if the graphite applied to the die adheres to a thin strip or a plate-shaped amorphous flake with a thickness of about 30 μm and a side length of 500 μm or less, the friction coefficient of the tool surface is mainly reduced. It only reduces it, does not adhere to most flakes, etc., and has no effect as an internal lubricant. Therefore,
The conventional warm-worked magnet has a problem that many cracks occur.

Also, unlike sintered magnets by powder metallurgy, which are molded at room temperature, in the case of warm working, the upsetting is usually performed at a temperature of 600 to 850 ° C, so the additive added between the individual flakes Although it is considered that the roles are basically different, the conventional invention does not consider that point at all.

Accordingly, the present invention provides an R-TM-B based warm-worked magnet which facilitates plastic working to obtain a crack-free one and has good magnetic properties by utilizing a chemical reaction between magnetic powders of additives. The purpose is to provide.

[Means for Solving the Problems] The present invention provides an RTB-based alloy (R is one or more rare earth elements including yttrium, T is a transition metal mainly composed of iron, and B is boron. ) Is rapidly quenched to obtain a ribbon or flake, and the ribbon or flake is pulverized, and a glass having a softening point of 500 to 800 ° C. is 0.5% by weight or less (0%
) And less than 0.5% by weight of graphite (excluding 0), and after mixing, the mixed powder is molded and densified to give a magnetic anisotropy by plastic working at 600-850 ° C. This is a method for producing a warm-worked magnet having an intermetallic compound represented by R ₂ T ₁₄ B as a main phase.

The present invention also relates to an intermetallic compound represented by R ₂ T ₁₄ B (R is one or more rare earth elements including yttrium, T is a transition metal mainly composed of iron, and B is boron). A warm-worked magnet having fine crystal grains having an average crystal grain size of 0.02 to 1 μm that is magnetically anisotropic, and having a carbon content of 0.2.
A warm-worked magnet characterized in that its content is 5% by weight or less, its oxygen content is 0.3% by weight or less, and the contained glass component and graphite component are distributed along flake boundaries.

In the present invention, the low melting glass is, for example, water glass [K ₂
OnSi (OH) ₂ ], PbO—B ₂ O ₃ —SiO ₂ , or a product called Deltaglaze, which is a product name used for room temperature casting and extrusion of Ti. The Deltaglaze (trade name) is used by mixing particulate glass in trichlene.

 Next, the role of glass in the present invention will be described.

In the case of using graphite alone, black spherical lumps are found everywhere. Although it is not possible to judge whether all of the black spherical objects are flakes or agglomerates of graphite powder, it is a fact that the process increases with the amount of addition and becomes coarse. This fact means that the graphite powder is concentrated locally. On the other hand, even when the same amount of graphite is added, the use of glass also does not cause this "lump".

Therefore, it is considered that the glass is softened by the heat at the time of upsetting and contributes to the uniform dispersion of the graphite powder.

By the way, from the magnetic properties, when comparing three types of glass alone, graphite alone, and glass + graphite composite, the order is glass + graphite composite> graphite alone> glass alone.

In other words, there is an effect that the magnetic properties are sufficiently improved by adding a suitable amount of graphite due to the synergistic effect of the composite addition. The result of the structure observation showed that the flow of the particles was significantly improved by the composite addition, and the particles flowed in a direction perpendicular to the upsetting direction.

Glass also contributes to the improvement of workability as an internal lubricant. This brings about an effect of improving mechanical properties which has not been obtained in a warm-worked magnet using a conventional glass as an external lubricant.

Although the chemical reaction between the low-melting glass and the graphite powder has not been clarified at present, it is considered that some catalytic action is present when considering the above-mentioned combined effect.

It seems that a slightly higher softening point of the glass can provide a glass having better magnetic properties and workability. From the above, the softening point of the glass used in the present invention is preferably from 500 to 800C.

In the present invention, the graphite powder determines the residual magnetic flux density after upsetting. However, in a method in which graphite is added between raw material flakes in powder form and then subjected to warm working, a decrease in coercive force is remarkably reduced with the addition amount. As the addition amount is further increased, lumps are formed and grown, and the plastic change of the fine crystal grains in each flake is inhibited.

Therefore, in the present invention, the amounts of glass and graphite added have an upper limit. As described in detail in (Embodiment 3), it is necessary to make adjustments so as to determine optimal amounts of residual oxygen and C for obtaining preferable magnetic characteristics.

 The results of the tissue observation indicate the following.

According to the observation results of the cross-section structure of the upsetting magnet when glass was added stepwise, little change was observed up to the addition amount of 0.3 wt%, but when 0.5 wt% was added, a band-shaped layer perpendicular to the upsetting direction was added. Occurred.

On the other hand, according to the observation of the cross section of the upsetting magnet when the glass was fixed at 0.1 wt% and graphite was added stepwise,
In the case of the non-added material, the flake boundary could hardly be determined, but the boundary clearly appeared with the added amount. However, when the addition amount is 0.3 wt% or more, a layer is formed at the boundary of the flakes, and particularly when 0.5 wt% is added, it becomes remarkable. Further 0.5wt
The% addition resulted in undulations in the flake stream in some places.

In addition, graphite is fixed at 0.3 wt% and glass is
According to the observation results at the time of charging up to 0.1 to 0.5 wt%, the boundaries of the flakes are all clearer than without graphite, but it can be seen that there is a slight difference in the flake flow. That is, 0.3wt% of glass 0.1wt% and 0.3wt%
The flake flow is more uniform during the addition. But 0.5w
With the addition of t%, there were places where the flow did not always flow perpendicularly to the upsetting direction due to the formation of layers that obstructed the flow.

As described above, the structure observation was performed using an electron microscope. One example is shown in FIG. 6 and FIG. FIG. 6 shows the metal structure of the fractured surface observed from the compression direction and the vertical direction of the warm working,
FIG. 7 shows a fractured metal structure observed from a direction parallel to the compression direction of the warm working. In each case, the upper row has a magnification of 2000x
The lower row has a magnification of 30,000 times.

When 0.3wt% of glass and 0.3wt% of graphite are added together ((b) in the figure), when they are not added ((a) in the figure)
It can be seen that a uniform structure can be obtained as compared with. On the other hand, as shown in (c) in the figure, when graphite is excessively added in an amount of 0.5 wt%, coarse lumps may be observed.

[Action] The reason why the warm-worked magnet of the present invention exhibits excellent magnetic properties as well as workability is largely influenced by the oxygen content and the C (carbon) content.

FIG. 4 shows changes in the amount of residual C and the amount of oxygen in the composite addition of glass and graphite. FIG. 4 shows that the amount of residual oxygen slightly increases with the amount of graphite added, which is considered to be due to the absorption of water due to handling in the atmosphere when mixed with flakes. The amount of residual C increases linearly with the amount of graphite added regardless of the amount of glass added.

Considering this figure and FIG. 3 shown below (Example 3), the carbon content for obtaining good magnetic properties is 0.5% by weight or less, and the oxygen content is 0.3% by weight (3000 ppm).
The following is preferred.

The warming magnet according to the present invention is affected by the upsetting speed. For external appearance, upsetting speed 0.5 ~ 0.1mm / sec
Although there is no effect on the degree of change, the deformation resistance has strain rate dependence. This tendency appears to be particularly pronounced as the strain increases. As the strain rate is reduced, the coercive force tends to decrease slightly. The most affected are the saturation magnetization and the residual magnetic flux density, which can be increased by decreasing the strain rate,
In particular, the rate of increase increases as the speed becomes slower than 0.006 (1 / second). Therefore, when processed at a low strain rate, the saturation magnetization and the residual magnetic flux density are high, and the coercive force does not decrease so much. As a result, it is possible to obtain a warm-worked magnet having a maximum magnetic energy product reaching 40 MGOe. In particular, the adoption of the constant temperature forging method can easily realize this.

According to the present invention, an improvement in the degree of orientation of crystal grains having a magnetocrystalline anisotropy also provides excellent magnetic properties. This could be known by X-ray analysis.

Also in the present invention, it is effective to add an organic liquid lubricant, such as diethylene glycol, already filed by the present inventors as an internal lubricant (Japanese Patent Application No. 63-247172).
issue).

However, the organic liquid lubricant has the following problems. For example, when manufacturing a large-sized upholstered magnet,
At the consolidation stage, a difference in heat transfer causes a time difference in vaporization, and local segregation of oxygen and carbon occurs. Therefore, there is a large variation in characteristics (particularly, coercive force) within one magnet.
This is an industrial problem particularly when large magnets are manufactured. Therefore, in the present invention, an excellent warm-worked magnet can be obtained by using an appropriate amount in an auxiliary manner.

Although the upper limit of the average crystal grain size in the present invention is up to about 1 μm, the finer the grain size, the better the magnetic properties.
m is preferable.

In the present invention, the average crystal grain size is fine as a feature of the warm-worked magnet. It is difficult to obtain ultra-fine crystals of less than 0.02 μm in an industrially stable manner with the current technology.
If it exceeds μm, the coercive force decreases, which is not preferable. In the present invention, an excessive addition of graphite powder (about 0.5 w
t%) tends to form coarse crystal grains. Many coarse crystal grains are distributed.

Here, the average crystal grain size is measured by a cutting method in a micrograph. That is, the value obtained by dividing the length of the cut line segment by the number of crystal grains that cut the line segment when a straight line is arbitrarily drawn on the photograph is defined as the crystal grain size, and the average value obtained for at least 20 points or more is averaged. The crystal grain size is used.

It should be noted here that the warm-worked magnet has a flat shape in a plane perpendicular to the C-axis of the crystal, and is in a thickness direction when cut along a plane including the C-axis. Therefore, the above-mentioned average crystal grain size refers to that on a plane perpendicular to the C axis.

Therefore, in the warm-worked magnet, it is necessary to consider not only the crystal grain size (c) on the plane perpendicular to the C axis but also the crystal grain size (a) in the direction parallel to the C axis. Incidentally, in the case of the warm-worked magnet according to the present invention, c is about 0.2 to 0.3 μm, a
Is about 0.1 μm. The ratio of c to a and c / a is called the aspect ratio. In the present invention, graphite is added in excess (about
If it is about 0.5 wt% or more), the magnetically isotropic component increases, so that the residual magnetic flux density also decreases.

In the present invention, when the carbon content exceeds 0.5% by weight, the magnetic properties are deteriorated, and when the oxygen content exceeds 0.3% by weight, the deformation resistance of the workpiece is remarkably increased, and the workability is deteriorated.

The alloy according to the present invention contains a transition metal T as a main component and a rare earth element R containing yttrium and boron B. The composition range conforms to that of a warm-worked magnet known in JP-A-60-100402. However, in the present invention, the transition metal T is mainly composed of iron, and not only transition metals in the narrow sense of Co, Ni, Ru, Rh, Pd, Os, Ir, and Pt, but also atomic numbers 21 to 29, 39 to 47. , 72 to 79, 89 or more in a broad sense.

Further, addition of Ga has an effect of remarkably improving the coercive force in a warm-worked magnet as already announced by the present inventors, so it is effective to add Ga as needed. Furthermore, addition of a known additive element according to the purpose does not depart from the effects of the present invention.

It is needless to say that the rare-earth element R is also mainly composed of Nd and Pr, and as is well known, can be partially replaced by Ce, sidinium or the like for the purpose of cost reduction, and partially replaced by Dy or Tb for the purpose of improving temperature characteristics. .

 Hereinafter, the present invention will be described specifically with reference to examples.

[Example] (Example 1) An alloy ribbon of 14.5% Nd, 6% B, 7.5% Co, and 0.75% Ga in atomic% was obtained by a rapid quenching method. The super-quenched flakes were taken from -32mesh (-
After coarsely pulverizing to 500 μm), the spherical mass was removed by a classifier. 0.2 wt% of graphite powder and 0.3 wt% of low melting glass were put into 150 g of the classified flakes.
The mixture was mixed for 10 minutes using a mold mixer. As graphite powder, scale-like graphite was used, and as the low-melting glass, an amorphous low-melting-point glass based on borosilicate pismuth was used. Table 1 shows the temperature characteristics of the glasses used.

The resulting flakes were cold molded at a pressure of 3ton / cm ^2, φ28.5
× 40.5 (ρ = 5.8 g / cm ² ) was used as a green compact. This green compact
An anisotropic upset magnet was obtained by using a 30-ton warm upsetting machine and working up to a working temperature of 740 ° C and an upsetting ratio of 3.90. The upset magnet was cut into 10.5 x 10.5 mm squares using an outer peripheral cutting machine and evaluated.

 The evaluation method and equipment used are shown below.

(A) Stress (deformation resistance) -strain From the load-displacement line at the time of warm upsetting, a stress in a strain region where cracks did not enter, that is, a stress at a strain of 0.1 was calculated. The stress was a nominal stress and used for comparison of workability under each condition.

(B) Magnetic properties A demagnetization curve was drawn with a BH tracer, and the second quadrant was read. For the measurement of the sample, five pieces were measured for one set-up magnet, and the average value was used as a representative value. The detailed measurement locations and dimensions are as shown in FIG. 5 (an example where a conventional end crack has occurred. The measurement locations are the same in the present invention.) A 10.5 mm square sample was cut out. . In the figure, the numbers indicate the cut-out portions of the samples, and the evaluation of the magnetic characteristics is the samples from the portions indicated by the numbers 1, 3, 5, 7, and 9,
Done. In addition, the observation with the optical microscope was performed on the sample from the location indicated by the numeral 8.

(C) The distributions of the residual C amount, the oxygen amount, and the C and glass components were measured by grinding the central portion of the upset magnet and using an oxygen concentration analyzer. The oxygen measurement was performed three times for each sample, and the average value was used as a representative value.

On the other hand, in the analysis of the glass, two elements, Si and Bi, were selected from the composition of the low-melting glass used in the experiment, and the distribution state of the entire glass was estimated from the distribution of these two elements. Bi, Si
In the analysis of EP, linear analysis was performed on a plane perpendicular to the upsetting direction using EPMA.

(D) Tissue The upset magnet was polished with emery paper and mirror-finished by buff polishing, and then the structure was observed with an optical microscope. The observation was made in a direction perpendicular to the upsetting magnet upsetting direction.

(E) Fracture surface The upset magnet was fractured, and the fracture surface was observed from a plane perpendicular to the upsetting direction, and the flow of crystal grains and the degree of abnormally grown grains at the boundary of the ultra-quenched flakes were compared.

 Moreover, composition analysis was performed by SEM-EDX as needed.

(F) Hardness After the cut-out upsetting magnet was mirror-finished, the hardness was measured using a micro Vickers. The hardness was determined by pressing a pyramidal diamond squeezer against the sample with a load of 1000 g based on the hardness conversion table from the diagonal length of the oppression. The measurement was performed on two surfaces in the upsetting parallel direction and two surfaces in the vertical direction, and five points were measured for each surface (10 points in each direction), and the average value was used as a representative value of hardness.

 The evaluation results in the case of this example are shown below.

(B) Stress (deformation resistance)-strain 0.48 (ton / cm ² ) for a strain rate of 0.1 (1 / sec)
Met. It is understood that the deformation resistance can be reduced by reducing the strain rate.

(B) Magnetic properties 4πIr = 12.3 (KG) iHc = 15.7 (KOe) (BH) max = 34.6 (MGOe) It can be seen that excellent permanent magnet properties can be obtained.

(C) Residual C content, oxygen content and C, glass distribution Residual C content = 0.32 (wt%) Residual oxygen content = 1700 (ppm) As a comparative example, a sample without low melting point glass was prepared and compared. In the case of the examples, it was found that the graphite powder was more uniformly dispersed between the flakes. It was found that the glass was evenly distributed between the flakes.

(D) Structure A structure showing a uniform composition flow was observed.

(E) Fracture surface It was observed that the flow of flakes was uniform.

(F) Hardness Vickers hardness was 650. As a comparative example, when a sample without glass and graphite was prepared, Hv
It was 580. Therefore, the permanent magnet according to the present invention slightly increases in hardness but does not become brittle.

Comparative Example 1 A sample was prepared by changing only the amount of the low-melting glass in Example 1, and the magnetic properties were evaluated.

FIG. 1 shows the change in the magnetic properties with respect to the glass addition amount. Both the residual magnetic flux density and the maximum energy product tend to increase gradually with the addition amount. Maximum energy product (B
H) max is 29MGOe when 0.1 wt% is added, and shows a peak near 0.3 wt%. △ 4πIr = 320G, △ (B
H) max = 2MGOe improved. On the other hand, the coercive force decreased with the amount of addition. However, the decrease in coercive force of the 0.5 wt% additive material was ΔiHc = 1090 Oe as compared with the non-additive material, which was not so large.

(Example 2) In order to determine the optimal ranges of the graphite powder and the low-melting-point glass addition amount, in the same manner as in (Example 1), samples in which only each addition amount was changed were prepared, and the magnetic properties were measured.

FIG. 2 shows the change in the magnetic properties when the glass is set to three levels of 0.1, 0.3 and 0.5 wt%, and graphite powder is added stepwise. Magnetic flux density with the addition of graphite,
The maximum energy product increased and showed a peak at 0.3 wt% of graphite when the glass content was 0.1 and 0.3 wt%. The maximum values of both glass and graphite were increased by △ 4πIr = 910G and △ (BH) max = 5.9MGOe compared to the non-added material when 0.3 wt% was added. At 0.5 wt% of glass, the residual magnetic flux density increased with a small amount of graphite, and decreased significantly at 0.5 wt%. On the other hand, the coercive force is significantly reduced as compared with the case where glass is used alone. The tendency was larger and decreased gradually as the combined amount of glass and graphite increased. 0.3% by weight of glass and 0.3% by weight of graphite with the highest energy product
The coercive force is 15430 Oe, which is about 2590 Oe compared to the additive-free material.
e dropped.

Therefore, the amount of graphite powder that maximizes (BH) max is 0.3 wt%, but the coercive force of 10 KOe or more is required due to the required use as a practical magnet such as heat resistance. Is preferably less than 0.5 wt%.

(Embodiment 3) The important point of the present invention is that graphite powder and low melting point glass are not simply added as lubricating oils, but are maintained at optimum values of oxygen and C between flakes in order to improve magnetic properties. It is to make it.

Therefore, the procedure was the same as in Example 1 except that the amounts of the graphite powder and the low melting point glass were variously changed in order to determine the optimal residual oxygen content and C content in order to obtain preferable magnetic properties (in particular, iHc). Samples were prepared in each case, and the relationship between the residual oxygen amount and C amount and the coercive force of each sample was examined. FIG. 3 shows the results. FIG. 4 shows the correlation between the amount of added graphite, the amount of oxygen, and the amount of C, using the added amount of glass as a parameter.

In the case of graphite powder, the increase in O due to the addition is extremely small, so that it is not necessary to consider the increase in O of both, as in the case of an organic liquid lubricant + glass. They correspond almost one-to-one. Therefore, it may be considered that the O increase amount depends only on the glass addition amount.

As a result, the coercive force decreases even if either graphite or glass increases. The tendency of the coercive force to decrease is smaller than the case where graphite is used alone, but shows the same tendency. Therefore, even in the case of composite addition, C and O
You have to consider the balance. That is, since both C and O react with the Nd component necessary for the coercive force during the warm upsetting, a decrease in the coercive force cannot be avoided even if either of them increases. For example, in order to obtain a coercive force of 16 kOe or more, if the graphite addition amount is determined to be 0.2 wt%, the glass addition amount becomes 0.4 wt% as a limit value by interpolating FIG. Further, according to the present invention, the warm workability is improved by adding a suitable amount of graphite powder and low-melting glass to the crushed raw material flakes or ribbons, resulting in improved workability. It is possible to suppress the occurrence.

[Effects of the Invention] According to the present invention, it is possible to provide a warm-worked magnet having improved workability, no crack during warm working, and excellent magnetic properties, and a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the amount of glass added and magnetic properties, and FIG.
The figure shows the relationship between the graphite addition amount and the magnetic properties when the glass addition amount is used as a parameter. FIG. 3 shows the relationship between the coercive force and the oxygen content when the glass addition amount and the graphite addition amount are used as parameters. FIG. 4 is a diagram showing the relationship between the graphite addition amount and the carbon / oxygen content when the glass addition amount is used as a parameter. FIG. 5 shows the end cracks of the warm-worked magnet and the magnetic property measurement points. FIG. 6 is a photograph showing a metal structure of a fractured surface observed from a direction perpendicular to the compression direction of warm working, and FIG. 7 is a photograph showing a metal structure of a fractured surface observed from a direction parallel to the compression direction of warm working. It is a photograph.

Continuation of front page (56) References JP-A-64-7504 (JP, A) JP-A-64-65202 (JP, A)

Claims (2)

(57) [Claims] An ultra-rapidly cooled molten metal of an RTB-based alloy (R is one or more rare earth elements including yttrium, T is a transition metal mainly composed of iron, and B is boron). A strip or flake is obtained, and the strip or flake is pulverized. The obtained pulverized powder is mixed with glass having a softening point of 500 to 800 ° C. by 0.5% by weight or less (0%).
) And less than 0.5% by weight of graphite (excluding 0), and after mixing, the mixed powder is molded and densified to give a magnetic anisotropy by plastic working at 600-850 ° C. A method for producing a warm-worked magnet having an intermetallic compound represented by R ₂ T ₁₄ B as a main phase. 2. R ₂ T ₁₄ B (R is one or more of rare earth elements containing yttrium, T is a transition metal mainly composed of iron,
B is a warm-worked magnet having an intermetallic compound represented by boron as a main phase and having a magnetic anisotropy average crystal grain size of 0.1.
It has fine crystal grains of 02 to 1 μm, has a carbon content of 0.5% by weight or less, an oxygen content of 0.3% by weight or less, and contains glass component and graphite component distributed along the flake boundary. A warm-worked magnet.