JP2000087194A - Alloy for electromagnet and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an alloy for an electromagnet having high density and practical soft-magnetic characteristics and excellent in workability by using a die compacting-sintering process by the conventional powder metallurgical processing. SOLUTION: This alloy has 5-50 μm average grain diameter in a section and a compsn. consisting of 0.005-0.05%, in total, of residual carbon and residual oxygen, 15-60% Co and the balance Fe or further contg. 0.5-4% one or more selected from V, Si, Cr, Al and Mn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alloy for an electromagnet manufactured by a powder metallurgy method, and more particularly to an alloy for an electromagnet excellent in soft magnetic properties and workability and a method for manufacturing a member made of the alloy. is there.

[0002]

2. Description of the Related Art The alloy for an electromagnet of the present invention is a so-called permendur, a soft magnetic alloy based on Fe--Co, having the highest magnetic flux density and magnetic permeability among magnetic materials. However, since this alloy is relatively brittle, the cold workability is poor, and many attempts have been made to improve the workability without impairing the magnetic properties. Usually, by adding about 2% of vanadium (V) to this alloy, the workability is improved while maintaining the magnetic characteristics and the electric characteristics. For example, as a 2V-permendur, the magnetic pole of the electromagnet or the printer is improved. It is used to manufacture head yokes.

[0003] Generally, an Fe-Co based alloy is produced by a casting method or a precision casting method, but at the time of casting, problems such as segregation of components and generation of cavities occur. Also, even if the workability is somewhat improved, this kind of alloy still cannot escape from the area of difficult-to-process materials, and in the cutting work to finish the shape of the final part, the low machinability and Problems such as a decrease in yield due to the occurrence of chipping remain. The powder metallurgy method is very effective as a means for solving such a problem, and has an advantage that members that are difficult to produce by the melt casting method can be mass-produced in a near net shape. However, it is difficult to obtain a high-density sintered alloy by generating Kirkendle voids only by sintering the mixed powder of the Fe powder and the Co powder after forming the mold. Also, F
The e-50% Co alloy powder has high hardness and very poor compression moldability, so that the density after compacting and sintering is low, and therefore, a material having practical magnetic properties cannot be obtained. Therefore, in order to obtain a product having a high magnetic flux density, which is a feature of the present alloy, recompression and HIP processing must be performed.

The products targeted by the alloy for electromagnets of the present invention have a high magnetic flux density, that is, B> 1.8T (Tesla, where H = 2000 A / m), and have good soft magnetic properties (high magnetic permeability, This is a large-sized product that requires low coercivity. Furthermore, in the final finishing of the component shape, various types of machining such as cutting, drilling, and tapping are performed, so that it is necessary to provide good workability. Therefore, there is a need in the art for the development of an alloy having such practical magnetic properties and excellent workability. On the other hand, the recent progress of injection molding technology has been remarkable, and powder metallurgy by conventional mold compression molding-sintering (hereinafter referred to as “conventional powder metallurgy”).
And a sintered body with a higher density can be obtained. This is because a fine powder having an average particle diameter of 1 μm to several tens of μm and having a high surface energy is used in the injection molding method.

However, in the injection molding method, a large amount of organic binder is used, so that a long binder removal step is required. In particular, parts used for electromagnets have a thickness of 10
It is a thick-walled large-sized part having a thickness of 200 mm or more and a weight of 200 g or more, and the binder removal step causes a significant increase in manufacturing cost. Furthermore, since the pressure of injection molding is lower and the density of the molded body is lower than that of the powder metallurgy method, there remains a problem such as a decrease in dimensional accuracy due to a large shrinkage amount after sintering.

In the above-mentioned example of the conventional powder metallurgy method,
All have performed high temperature sintering of 1300-1400 degreeC,
It is effective in improving soft magnetic properties by increasing the density and coarsening the crystal grains.However, when cutting, drilling, tapping, etc. is performed to finish the final part shape after sintering, the crystal Conversely, coarsening of grains causes chipping or cracking.

[0007]

In view of the above-mentioned state of the art, the present inventors have made various studies. That is, an object of the present invention is to provide an electromagnet alloy having high density, practical soft magnetic properties, and excellent workability by using a conventional mold compression molding-sintering process by powder metallurgy. To provide. More specifically, it is excellent in cutting workability, drilling workability, tapping workability, etc. when finishing to the final part shape, the part thickness is 10 mm or more, and the weight is 200
It is an object of the present invention to provide an electromagnet alloy having a large thickness of at least g and a method for manufacturing the same.

[0008]

In general, the soft magnetic properties of Fe-Co based alloys are significantly affected by the contents of impurities such as residual carbon and residual oxygen in the alloy, the crystal grain size of the alloy, and the heat treatment conditions. You. In particular, when the content of impurities such as residual carbon and residual oxygen in the alloy is large,
Among the soft magnetic properties of the alloy, the magnetic permeability and coercive force, which are easily affected by the crystal structure, are significantly reduced. Therefore, reducing the impurity content of the raw material powder, setting the necessary minimum amount of molding lubricant,
It is necessary to take measures such as strict process control for these impurities mixed in the middle of the manufacturing process. In addition, Fe-Co
At around 730 ° C., ordered transformation occurs in the base alloy, embrittlement is likely to progress, and the cold workability of the alloy is significantly impaired.
This embrittlement can be prevented by a solution treatment of rapid cooling after solution heating in a temperature range of 800 to 1100 ° C., and annealing is performed after cold working. The same heat treatment as that of the molten casting material may be applied to the sintered material, but this complicates the manufacturing process and increases the manufacturing cost.

On the other hand, with respect to the crystal grain size of the Fe—Co-based alloy, as described in the description of the prior art, improvement in soft magnetic characteristics is expected due to coarsening, but workability tends to decrease. is there.

The present inventor has conducted various studies on the effects of the content of impurities such as residual carbon and residual oxygen in the alloy, the crystal grain size of the alloy, and the heat treatment conditions on the soft magnetic properties of the Fe—Co based alloy. Was done. According to the knowledge, it is well known that an alloy having a large crystal grain size and a small amount of impurities such as residual carbon and residual oxygen has excellent soft magnetic properties. It has been found that the crystal grain size is remarkably reduced, and that alloys having an average grain size less than a certain size exhibit excellent magnetic properties regardless of the amount of impurities. An alloy having such a fine crystal grain size is also excellent in various machinability.

The present inventor has conceived that an Fe—Co based alloy having a total content of residual carbon and residual oxygen of the alloy of 0.005 to 0.05% and an average crystal grain size of 5 to 50 μm is practically usable. The present inventors have found that both a certain soft magnetic property and workability can be achieved, and completed the present invention. In the present invention, “%” of the above content and other compounding amounts is “weight percentage” unless otherwise specified. Further, the average crystal grain size of the alloy is defined as a crystal grain size of 1/2 of the sum of the maximum length and the minimum length up to both ends passing substantially through the center of the crystal grain from the cross-sectional microstructure of the sample.
^This is the average value of the crystal grain size when ^two or more areas are observed.

That is, the gist of the present invention is that Co having an average crystal grain size of the alloy cross section of 5 to 50 μm and a total content of residual carbon and residual oxygen in the alloy of 0.005 to 0.05%:
An object of the present invention is to provide an electromagnet alloy having a composition of 15 to 60% and the balance of Fe. The average grain size of the alloy cross section is 5 to 50 μm, the total content of residual carbon and residual oxygen in the alloy is 0.005 to 0.05%, and Co: 15
-60%, one or two of V, Si, Cr, Al, Mn
Species or more: To provide an alloy for electromagnet having a composition consisting of 0.5 to 4% and the balance of Fe. Another object of the present invention is to provide an electromagnet alloy member having the above alloy composition, the amounts of residual carbon and residual oxygen, and the average crystal grain size, and having a density ratio of 94% or more. It is still another object of the present invention to provide a thick and large-sized electromagnet alloy member having a thickness of 10 mm or more and a weight of 200 g or more. Another gist of the present invention is to provide an alloy powder having the above composition and an average particle diameter in the range of 1 to 40 μm by using an organic binder of 0.3 to 2.5%.
An object of the present invention is to provide a method for producing an alloy member for an electromagnet obtained by granulating to an average particle diameter in the range of ~ 400 µm, forming a mold, and then sintering in a non-oxidizing atmosphere.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the amounts of alloy components and the effects thereof according to the present invention will be specifically described. First, the electromagnet part which is the target product of the present invention is required to have a high magnetic flux density of B> 1.8T (where H = 2000 A / m) and good soft magnetic properties (high magnetic permeability, low coercive force). Therefore,
The composition of the alloy is selected to satisfy this condition. As will be described in detail in the examples below, if the Co content is less than 15%, a desired magnetic flux density cannot be obtained. On the other hand, if the Co content exceeds 60%, both the magnetic flux density and the magnetic permeability decrease. There is a tendency and the desired value cannot be obtained. Therefore,
The Co content of the alloy composition of the present invention is preferably in the range of 15 to 60%. The content of Co is preferably 20 to 5%.
0%. Such Fe having good soft magnetic properties
-Co-based alloys are difficult to machine,
By containing one or more elements of V, Si, Cr, Al, and Mn in the range of 4%, the effect of reducing the crystal grain size and improving the workability can be obtained. If the content of these elements is less than 0.5%, almost no effect is recognized, and if it exceeds 4%, the soft magnetic properties are deteriorated. Therefore, in the present invention, the content of one or more elements of V, Si, Cr, Al, and Mn is limited to the range of 0.5 to 4%.

The method of improving workability by making crystal grains finer using the addition of such an element results in a decrease in soft magnetic characteristics and has a limited effect of the addition. In particular, in order to improve the machinability, drill workability, tapping workability, and the like when finishing to the final part shape, it is desirable to make the crystal grain size smaller.

In the present invention, the reason why the average grain size of the alloy cross section is 5 to 50 μm and the total content of residual carbon and residual oxygen in the alloy is limited to the range of 0.005 to 0.05% is as follows. This is because magnetic characteristics and workability are considered.
First, the reason why the average crystal grain size of the alloy cross section is limited to the range of 5 to 50 μm is that if the grain size is smaller than 5 μm, the soft magnetic properties, particularly the magnetic permeability, decrease. Furthermore, in order to make the average crystal grain size of the sintered alloy less than 5 μm, it is necessary to use a starting material powder finer than 1 μm, and such a powder is not practical because it increases the production cost. Actually, when a fine powder having a particle size of less than 1 μm is used, the crystal particle size after sintering tends to be coarse, and the soft magnetic properties are improved, but various machinability is reduced. On the other hand, when the average crystal grain size exceeds 50 μm, the soft magnetic properties are improved, but the workability is reduced and chipping or the like is liable to occur. The reason that the total content of residual carbon and residual oxygen in the alloy is limited to the range of 0.005 to 0.05% is that if the total content of residual carbon and residual oxygen is less than 0.005%, then This is because the soft magnetic properties of the bonded gold are improved, but the crystal grain size cannot be reduced, and therefore, the finish workability to the final shape is reduced. Further, in this case, there is a large practical problem such as difficulty in controlling the sintering atmosphere (dew point). When the total content of residual carbon and residual oxygen exceeds 0.05%, soft magnetic properties,
In particular, it is not preferable because the magnetic permeability and the coercive force decrease.

The higher the density ratio of the alloy (the lower the porosity), the better the magnetic properties. If the density ratio is about 90% in the range of the alloy composition of the present invention, the amount of residual carbon and residual oxygen, and the average crystal grain size as described above, a material having a higher maximum magnetic permeability than the conventional alloy can be obtained. Can be When the density ratio is 94% or more, the maximum magnetic permeability becomes 4000 or more. According to the production method of the present invention, a density ratio of about 96% can be obtained. However, in order to further increase the density and improve the magnetic characteristics, the sintering temperature is set higher in consideration of an increase in cost. And HIP processing are also effective means. ADVANTAGE OF THE INVENTION According to this invention, if only the sintered compact (density ratio 85-90%) of the same performance as a conventional one is obtained, it can set at a lower temperature and shorter time than the conventional sintering conditions. Can not be overlooked.

Next, the manufacturing method of the present invention will be described. First, for the purpose of obtaining a sintered alloy having high density and practical magnetic properties and workability, and controlling the average crystal grain size to 5 to 50 μm, the average particle size of the raw material powder is 1 to 40 μm. Is used. By using such a metal fine powder, the sinterability is greatly improved and the density of the sintered body is improved. The sinterability improves as the raw material powder becomes finer, but the average particle size is 1 μm.
If it is smaller than m, the production cost increases, the average crystal grain size of the alloy cross section after sintering is rather coarsened, and the workability is reduced. On the other hand, when the average particle size is larger than 40 μm, the effect of improving sinterability is low. Therefore, in the present invention, the average particle size of the raw material powder is limited to the range of 1 to 40 μm. The average particle size capable of greatly improving the sinterability is desirably 1 to
It is in the range of 20 μm.

Next, an organic binder is added to the raw material fine powder at 0.3.
％ 2.5% and granulated so that the average particle size becomes 40-400 μm. By using such a granulated powder, the fluidity of the granulated powder and the filling property into a molding die are improved, and a mold can be formed by a conventional powder metallurgy method. The amount of the organic binder to be added is 0.3 to 2.5% based on the weight (100%) of the metal powder. If the amount of the organic binder is less than 0.3%, the particle strength of the granulated powder cannot be obtained, the powder is broken during the powder supply process before molding, and the fluidity is reduced. As a result, the moldability deteriorates, for example, the broken powder enters the gap between the die and the upper and lower punches, causing a phenomenon of die galling. On the other hand, when the addition amount of the organic binder exceeds 2.5%, the apparent density of the granulated powder decreases, and as a result, a high-density sintered body cannot be obtained. In addition, residual oxygen and residual carbon in the alloy increase, thereby deteriorating magnetic properties and workability. Therefore, the addition amount of the organic binder is limited to the range of 0.3 to 2.5%.

There is no problem in combining two or more of these organic binders and adding them to the metal powder. Also in this case, if the total amount is less than 0.3%, the strength of the granulated powder cannot be obtained, the powder particles are broken in the powder supply process before molding, and the fluidity and the moldability decrease. On the other hand, if the addition amount exceeds 2.5%, the apparent density of the granulated powder decreases, and as a result, a high-density sintered body cannot be obtained. Further, residual oxygen and residual carbon contained in the alloy increase, thereby deteriorating magnetic properties and workability. Therefore, even when two or more kinds of organic binders are used in combination, the addition amount is preferably in the range of 0.3 to 2.5%. Organic binders used for granulation include polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP),
Methylcellulose (MC), polyacrylamide (P
A), polyethylene glycol (PEG) and the like. These are prepared by using water or industrial alcohol as a solvent and adding them to a metal powder as an aqueous solution or an alcohol solution to prepare a granulated powder. Considering the strength of the granulated powder, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol and the like are preferred.

In the present invention, a granulated powder was prepared using a stirred fluidized bed granulator. In this apparatus, after a predetermined amount of granulating metal powder is charged into a chamber, a stirrer (rotor) mounted below the chamber is rotated at a high speed to stir and flow the metal powder in the chamber. Thereafter, the above-mentioned organic binder solution is sprayed from a lower nozzle, and a small amount is coated on the surface of the metal powder. After spraying a predetermined amount of the organic binder solution, the solution component of the organic binder is gradually volatilized and dried by warm air blown from another nozzle below to obtain a desired granulated powder. Of course, a granulating device such as a fluidized bed device without a rotor or a spray dryer can also be used, but in such a device, granulated powder having a hollow inside is generally liable to be generated, and therefore the apparent density is low. Tend. The above-described apparatus has an advantage in that a binder can be attached to the surface of the metal fine powder, and at the same time, a dense granulated powder can be obtained by collision with the rotor.

The particle size of the granulated powder can be controlled by the type, concentration, supply amount and supply time of the organic binder solution, rotation speed of a stirrer (rotor), hot air drying temperature and drying time. Granulated powder composed of fine metal powder and organic binder has poor fluidity when the average particle diameter is smaller than 40 μm, and the granulated powder having a diameter larger than 400 μm has to be subjected to granulation for a long time, thereby increasing the processing cost. . Therefore, the average particle size of the granulated powder is 40 to
It is preferably within the range of 400 μm. The average particle size of the granulated powder is desirably 40 to 200 μm. In addition, the process becomes complicated, but after classifying the obtained granulated powder, by blending so as to have a predetermined particle size distribution, a granulated powder having further excellent fluidity and filling property can be obtained. . The granulated powder thus obtained is subjected to a known conventional powder metallurgy process, that is, a process such as die compression molding-sintering or die compression molding-sintering-heat treatment.

Hereinafter, an example of compression molding and sintering of a mold using the granulated powder of the present invention will be further described. The granulated powder of the present invention can be compression-molded using a general molding die. In order to obtain a high-density sintered body, it is preferable that the molded body also has a high density, and the molding pressure should be increased, but when the molding pressure is increased, it is necessary to strengthen the mold structure or take measures against mold wear. Therefore, the molding pressure is generally 5 to 7
ton / cm ² is desirable.

The sintering can be performed using a normal sintering furnace under normal sintering conditions. The sintering is performed in a reducing atmosphere or in a vacuum from the viewpoint of sinterability. The binder removal process before sintering may be omitted because the amount of binder added is as small as 0.3 to 2.5% as compared with the injection molding method, etc. In this case, it is desirable to perform the treatment in a reducing atmosphere at 400 to 600 ° C. for about 30 minutes to 1 hour. The sintering conditions are appropriately selected according to the type of the granulated powder to be used. The total amount of residual carbon and residual oxygen in the sintered alloy is 0.005 to 0.05%, and the average crystal grain size is It is held so as to be in the range of 5 to 50 μm. The Fe-Co-based and Fe-Co-V-based alloys of the present invention are preferably set in a reducing atmosphere at 1000 to 1400C for 1 to 5 hours. Desirably, 105
The sintering conditions are 0 to 1350 ° C. for 1 to 3 hours.

[0024]

In the present invention, the sinterability is greatly improved and the average crystal grain size of the sintered alloy is reduced by using an Fe-Co base alloy fine powder having an average particle size of 1 to 40 μm as a raw material powder. It can be controlled to 5 to 50 μm. The granulation of the alloy powder is performed using Fe-Co having an average particle size of 1 to 40 μm.
The base alloy fine powder is granulated to have an average particle size of 40 to 400 μm.
By making the powder coarse, the fluidity and moldability of the powder into the molding die are improved. Further, by setting the amount of the binder to be added at this time to 0.3 to 2.5%, the filling property of the powder into the molding die is improved, and the total content of residual oxygen and residual carbon in the alloy is reduced to 0%. .005-0.05
%, The crystal grain size of the alloy can be reduced. For this reason, finish workability to the final shape of the alloy can be improved. The granulated powder obtained as described above is subjected to a known conventional powder metallurgy process, that is, a process such as die compression molding-sintering, or die compression molding-sintering-recompression-annealing. The desired shape of F
An e-Co based sintered part can be obtained.

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

<Example of Co content test> Co as a raw material powder
Containing 10%, 30%, 50% and 70%
0%, 0.5%, 2% and 4% of V powder were added to the water atomized powder of the Co alloy composition at an internal rate of 0%, respectively, and the mixture was granulated using a stirred fluidized bed granulator. After 3 kg of the raw material powder was charged into the granulator, the whole amount of an aqueous solution containing 30 g of polyvinyl alcohol as a binder was sprayed, and then dried to prepare a granulated powder having an average particle diameter of 40 to 400 μm. The above granulated powder is molded into various test pieces at a molding pressure of ³ to 7 ton / cm ² , and 1000
Sintered at １３1350 ° C. for 1-5 hours. The test piece has an inner diameter of 2
A ring-shaped sintered body having a diameter of 0 mm, an outer shape of 30 mm, and a height of 5 mm was wound with a primary coil of 100 times and a secondary coil of 20 times, and a magnetic flux density (B ₂₅ ) and a maximum magnetic permeability (μ _m ) Was measured. The measurement results are shown in FIGS. FIG. 1 shows the relationship between the Co content and the magnetic flux density of four types of V-content Fe—Co alloys, and FIG.
5 is a graph showing the relationship between the Co content of an o-alloy and the maximum magnetic permeability. Examination of these graphs shows that the Co content is 1
If it is lower than 5%, the magnetic flux density tends to decrease, and an alloy having a desired magnetic flux density cannot be obtained. On the other hand, when the Co content exceeds 60%, both the magnetic flux density and the high magnetic permeability tend to decrease.

<Production Test Example> Fe-49 was used as a raw material powder.
Various average particle diameters of the Co-2V alloy composition and the Fe-50Co alloy composition (2 μm, 8 μm, 20 μm, 40 μm, 50 μm)
water atomized powder having a micron size) was used. Granulation was performed using a stirred fluidized bed granulator. After adding 3 kg of the raw material powder to the granulator, various amounts of polyvinyl alcohol aqueous solution or polyvinyl pyrrolidone.
After adding the methanol solution by spraying, it was dried to prepare a granulated powder having an average particle size of 40 to 400 µm. Table 1 shows the properties of the obtained granulated powder.

When a raw material powder having an average particle size of 8 μm and polyvinyl alcohol are used, the amount of the binder to be added is 0.1%.
At 2%, the particle size of the granulated powder is small and the strength of the granulated powder is low, so that the moldability is poor such that the particles break during molding and enter the clearance of the mold (Test Example 2). When the amount of the binder added is 0.3% or more and the average particle size after granulation is 40 μm or more, granulated powder having good fluidity and moldability can be obtained (Test Examples 4, 5, 7, and 8). When polyvinyl pyrrolidone was used as the binder, the same results as in the case of polyvinyl alcohol were obtained (Test Example 6). Fluidity and molding were obtained even when raw material powders having average particle diameters of 2 μm, 20 μm, 40 μm, and 50 μm were used. A granulated powder having good properties is obtained (Test Examples 1, 9 to 11). Powder mixed with zinc stearate (Zn-st) commonly used in powder metallurgy does not flow (Test Example 12). Also, when using Fe-20Co alloy powder and Fe-50Co alloy powder as the raw material powder, if the amount of the binder of the present invention is added,
A granulated powder having good fluidity and moldability is obtained (Test Examples 13 and 14).

The granulated powder thus obtained is mixed with 3 to 7
Each test piece was molded into a mold at a molding pressure of ton / cm ² and sintered at 1000 to 1350 ° C. for 1 to 5 hours in a hydrogen atmosphere. The test piece for magnetic measurement is a ring-shaped sintered body having an inner diameter of 20 mm, an outer diameter of 30 mm, and a height of 5 mm. The primary coil is wound 100 times, the secondary coil is wound 20 times, and the magnetic flux density (B ₂₅ ) to measure the maximum permeability (μ _m). The test piece for evaluation of workability was a sintered body of 50 mm × 50 mm × 15 mm. After cutting the surface, a drilling of φ3 and tapping of M3 were performed to evaluate the presence or absence of chipping and the state of the thread.

Table 2 shows the density ratio, the residual carbon content, the residual oxygen content, the average crystal grain size, the DC magnetic properties and the results of the evaluation of the workability of the obtained sintered body. When the amount of the binder added was 0.2%, the compactability of the granulated powder was poor and the density ratio was relatively low, so that the maximum magnetic permeability was lower than 4000 (Test Example 2). When the amount of the binder added is 0.3% or more, a high density ratio of 95% or more can be obtained, and good magnetic properties can be obtained (Test Examples 1, 3 to 5, and 7). However, the average particle size of the granulated powder is 4
Those having a thickness of less than 0 μm have poor workability (Test Example 3). When polyvinylpyrrolidone is used as the binder, the same as in the case of polyvinyl alcohol, a high density ratio and good magnetic properties are obtained (Test Example 6). However, if the amount of the binder exceeds 3%, the amount of residual carbon and the amount of residual oxygen after sintering become extremely large, so that the growth of crystal grains is hindered, the magnetic properties are remarkably reduced, and the workability is also poor ( Test Example 8). As the average particle size of the raw material powder increases, the sinterability tends to decrease. If the average particle size exceeds 40 μm, the density ratio of the sintered body decreases, and the magnetic properties decrease and the workability becomes poor. (Test Examples 9 and 11). A powder mixed with zinc stearate (Zn-st) has poor magnetic properties and workability because a compactability is poor and a high-density sintered body cannot be obtained (Test Example 12). Fe-20Co, Fe-
Even when the 50Co alloy powder is used, a high density ratio and good magnetic properties can be obtained (Test Examples 13 and 14). Regarding the workability, the granulated powder had a small average particle size (Test Example 3), the sintering had a large amount of residual carbon and oxygen (Test Example 8), and the average crystal particle size was large (Test Example 1
1, 12) tend to decrease workability, but all of the examples of the present invention are excellent in magnetic properties and workability. An alloy having a maximum magnetic permeability of 4000 or more and having good workability is an Fe-Co-based alloy having the above-described composition, and the total amount of residual carbon and residual oxygen is 0.005.
〜0.05%, average crystal grain size is 5-50 μm, and density ratio is 94% or more.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

As described above, according to the present invention, it is possible to easily use a metal fine powder having a high sintering property, and to use a conventional mold compression molding and sintering process of powder metallurgy. ,
An alloy for an Fe-Co based electromagnet having excellent soft magnetic properties and workability can be manufactured. Further, according to the present invention, it is possible to mass-produce an alloy for a Fe-Co-based electromagnet having a large thickness and a thickness of 10 mm or more, which is difficult to produce by an injection molding method, at low cost.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the Co content and the magnetic flux density of four types of V-content Fe—Co alloys.

FIG. 2 is a graph showing the relationship between the Co content and the maximum magnetic permeability of a similar Fe—Co alloy.

Claims (5)

[Claims] An average grain size of the alloy cross section is 5 to 50 μm.
And the sum of the residual carbon content and the residual oxygen content in the alloy is 0.
An alloy for an electromagnet having a composition of Co: 15 to 60% and the balance of Fe, which is 005 to 0.05%. 2. The average grain size of the alloy cross section is 5 to 50 μm.
And the sum of the residual carbon content and the residual oxygen content in the alloy is 0.
005-0.05%, Co: 15-60%, V,
One or more of Si, Cr, Al, and Mn: 0.5
An alloy for an electromagnet having a composition of about 4% and the balance of Fe. 3. The alloy for an electromagnet according to claim 1, wherein the density ratio is 94% or more. 4. The thickness is at least 10 mm and the weight is 200 g.
The alloy for an electromagnet according to claim 1, wherein the alloy has a thick and large shape as described above. 5. An alloy powder having an alloy composition according to claim 1 or 2 having an average particle diameter of 1 to 40 μm, using an organic binder of 0.3 to 2.5%. A method for producing an alloy member for an electromagnet, comprising granulating to an average particle diameter of 40 to 400 μm, and sintering in a non-oxidizing atmosphere after molding.