JP2005133142A - Cast iron based soft magnetic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cast iron based soft magnetic material which is advantageous to the increase of magnetic flux density. <P>SOLUTION: The cast iron based soft magnetic material has a ferritic iron based matrix, and carbide formed by one or more carbide forming elements is dispersed into the ferritic iron based matrix. As the carbide, at least one kind selected from vanadium carbide, tungsten carbide, molybdenum carbide and titanium carbide can be examplified. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cast iron soft magnetic material for a magnetic circuit.

  Conventionally, soft magnetic materials used for magnetic circuit members are required to have high specific resistance in order to reduce iron loss such as eddy current loss. Therefore, in order to reduce iron loss, laminates in which sheets such as iron plates and silicon steel plates are laminated in the thickness direction, or sintered powder compacts obtained by sintering green compacts in which iron powder is hardened are mainly used. Yes. Further, in order to further reduce iron loss, when the insulating material is interposed between the plate members constituting the laminated body, or when the sintered powder molded body is formed, the surface of the iron powder particles is electrically charged. What coat | covered the film | membrane with high insulation is known.

  However, there is a problem that it is difficult to form a soft magnetic material formed of a laminate in which plate materials such as iron plates and silicon steel plates are laminated into a three-dimensional shape or a complicated shape. Moreover, in the soft magnetic material which passed through the process which compacts iron powder, there exists a problem which needs to make a press pressure high in order to make a compactness high. Increasing the press pressure shortens the die life and increases costs. In addition, if the pressing is not performed uniformly, density unevenness occurs, which causes cracking of the soft magnetic material. Furthermore, the size is limited by the surface pressure at the time of pressing, and the degree of freedom is poor. Furthermore, in a soft magnetic material formed of a laminate, when the operating temperature increases, warpage and deformation cannot be ignored due to deformation, and strength and magnetic properties may be reduced due to the peeling.

Therefore, in recent years, cast iron-based soft magnetic materials for magnetic circuits formed of spheroidal graphite cast iron in which graphite is dispersed in a ferrite-containing iron-based matrix have been developed (Patent Document 1, Patent Document). 2).
JP 2002-280210 A JP 2002-322532 A

  According to the soft magnetic materials of Patent Document 1 and Patent Document 2 described above, since the molten metal containing carbon is poured into the cavity of the mold and solidified by casting, the moldability is good and the three-dimensional Even if it is a general shape or a complicated shape, the advantage that it can be formed easily while suppressing cost is obtained. Furthermore, the graphite produced in the cast iron structure has a higher electrical resistance than an iron-based matrix with a lower electrical resistance, so it can contribute to diverting the induced current generated inside the soft magnetic material. It is advantageous for increasing resistance and reducing iron loss.

  An object of the present invention is to provide a cast iron-based soft magnetic material that can further enhance the performance of the soft magnetic material described above and is advantageous for increasing the magnetic flux density.

  The present inventor has been diligently developing cast iron-based soft magnetic materials based on the above-described problems. And we found that the above-mentioned problem can be achieved by forming a cast iron-based soft magnetic material in which carbides generated by carbide-generating elements such as vanadium are dispersed in a ferrite-based iron matrix, and confirmed by tests The present invention has been completed. The reason is not necessarily clear, but is presumed as follows.

  That is, the carbon contained in the ferritic iron-based matrix is consumed by the carbide-forming elements to generate carbides, so that the amount of carbon in the ferritic iron-based matrix is reduced, and thus the ferritic iron-based matrix is made of pure iron. It is presumed that the composition becomes closer, the magnetic permeability is improved, and the magnetic flux density is improved.

  Further, in cast iron in which graphite is dispersed in a matrix, it has recently been reported that a minute gap is formed at the boundary between the edge of the graphite and the matrix. This gap is considered as one of the factors of graphite peeling in cast iron. Therefore, when the carbon contained in the cast iron is not formed in the form of carbides such as vanadium carbide but only as graphite, the influence of this gap becomes large, which may cause a loss related to magnetic permeability. On the other hand, if the carbon contained in the cast iron is positively present not only in the form of graphite but also in the form of a carbide such as vanadium carbide (including the case where the carbon exists in the form of both graphite and carbide). ), It is presumed that these carbides can reduce the effect of the gap described above and can reduce the loss of magnetic permeability.

  The cast iron-based soft magnetic material according to aspect 1 is characterized in that it has a ferrite-based iron-based matrix, and carbides generated by the carbide-forming elements are dispersed in the ferrite-based iron-based matrix.

  Ferrite is α-iron-based, and the amount of carbon in solid solution is small and the amount of carbon solid solution is close to that of pure iron. Therefore, the ferritic iron-based matrix is inherently excellent in magnetic properties and has high magnetic permeability. .

  According to the cast iron soft magnetic material according to aspect 1, it is formed by solidifying and cooling the molten metal, and when the carbide generating element generates carbide, the carbon contained in the ferritic iron-based matrix is generated as carbide. Since the elements are consumed, the amount of carbon in the ferritic iron-based matrix is reduced. As a result, the ferritic iron-based matrix becomes closer to the composition of pure iron, and it is presumed that the permeability in the iron-based matrix is further improved and the magnetic flux density is improved.

  Here, the ferritic iron-based matrix means that when the entire iron-based matrix excluding graphite and carbides (carbides such as vanadium carbide, tungsten carbide, molybdenum carbide, and titanium carbide) is 100%, ferrite in an area ratio. The thing which occupies 40% or more. Accordingly, when the iron-based matrix is 100%, the ferrite can be 50% or more, 60% or more, 80% or more in area ratio, and further 90% or more and 95% or more. It can also be set to 100%. The larger the ferrite area ratio, the richer the ferrite and the better the magnetic permeability.

  Here, the area ratio of ferrite is the area ratio at the cut surface of the soft magnetic material, and the area of graphite and the area of carbides (carbides such as vanadium carbide, tungsten carbide, molybdenum carbide, titanium carbide) are subtracted from the area of the visual field. When the area is 100%, it means the ratio of the area occupied by ferrite in 100%. The ferritic iron-based matrix is targeted both when no cementite and pearlite are generated and when cementite and pearlite are generated. Here, when cementite or pearlite is generated, the area ratio is determined so that cementite or pearlite is not included in the carbide such as the vanadium carbide.

  Therefore, examples of the ferrite-based iron matrix include ferrite-pearlite, ferrite-austenite, and the like in addition to ferrite. Here, when chill is generated in an as-cast state, heat treatment can be performed in a high temperature region (generally 700 ° C. or more). Magnetic properties can be improved by increasing the proportion of ferrite by heat treatment.

  In addition, since carbide generally has a higher hardness than a ferritic iron-based matrix, it can contribute to improving the wear resistance of cast iron-based soft magnetic materials, and is suitable for soft magnetic materials used in a sliding environment.

  According to the cast iron-based soft magnetic material according to aspect 2, the carbide is granular. If the carbide is granular, the strength of the soft magnetic material is ensured, and even when the usage environment is severe, the generation of cracks is suppressed, which can contribute to a longer life.

  According to the cast iron-based soft magnetic material according to the aspect 3, the carbide is an average particle size of 100 μm or less. A carbide having such a size can contribute to a long life even when the usage environment is severe. The above-mentioned carbide can be made into an average particle of 80 μm or less, a particle of 50 μm or less, or a particle of 40 μm or less, and can be a particle of 2 μm or more on the lower limit side.

  According to the cast iron soft magnetic material according to aspect 4, the carbide generating element is at least one of vanadium, tungsten, molybdenum, and titanium, and the carbide is at least one of vanadium carbide, tungsten carbide, molybdenum carbide, and titanium carbide. It is one type. These carbides are generated in the process of solidifying and cooling the molten metal.

  Since vanadium easily generates carbides, the carbon contained in the ferrite-based iron-based matrix is consumed and generated as carbides. Therefore, the composition of the ferrite-based iron-based matrix can be brought close to the pure iron composition. For this reason, it is presumed that the permeability in the ferritic iron-based matrix is further improved and the magnetic flux density is improved. Like vanadium, elements such as tungsten, molybdenum, and titanium have the function of generating carbides. Therefore, as in the case where vanadium carbides are generated, the carbons consumed in the ferrite-based iron matrix are consumed. Therefore, the composition of the ferritic iron-based matrix can be brought close to the pure iron composition. For this reason, it is presumed that the magnetic permeability in the ferritic iron-based matrix is improved and the magnetic flux density is improved.

  According to the cast iron-based soft magnetic material according to aspect 5, when the cast iron-based soft magnetic material is taken as 100%, the carbide generating elements are included in a weight ratio of 8% or less. Thus, since the carbide generating element is contained, it is possible to contribute to the generation of carbon contained in the ferritic iron-based matrix as a carbide by the carbide generating element. For this reason, the amount of carbon in the vicinity of the carbide in the ferritic iron-based matrix is reduced, the vicinity of the carbide is close to pure iron, the magnetic permeability is improved, and the magnetic flux density is improved. When the cast iron-based soft magnetic material is taken as 100%, the above-mentioned carbide forming elements such as vanadium are 7% or less, 6% or less, 4% or less, further 3% or less, 2% on the upper limit side by weight ratio. The lower limit may be 0.1% or more, 0.2% or more, or 0.3% or more. Accordingly, examples of the content of the carbide generating element include 0.1 to 6%, 0.2 to 4%, and 0.3 to 3% by weight. However, it is not limited to these.

  According to the cast iron-based soft magnetic material according to aspect 6, graphite is dispersed in the ferrite-based iron-based matrix, and the graphite is spheroidal graphite, CV graphite (compact vermicular graphite), flake graphite, and lump graphite. , Present in the form of at least one of polymorphic graphite, rose graphite, and eutectic graphite. In general, a large number of graphite is dispersed in cast iron. Since graphite has a higher specific resistance than a ferritic iron-based matrix, it can increase the specific resistance of cast iron-based soft magnetic materials and can bypass eddy currents, contributing to a reduction in eddy current loss. Here, the spherical graphite refers to spherical graphite or pseudo-spherical graphite produced when a molten metal is treated with a spheroidizing agent. In the present invention, since a carbide forming element such as vanadium is positively added, even when the molten metal is spheroidized with a spheroidizing agent, the spheroidizing rate is insufficient and the spheroidizing rate of the spherical graphite is reduced. There is a risk. CV graphite (compact vermicula graphite) is also called worm-like graphite. Multi-shaped graphite is a multi-shaped graphite. Generally, when spheroidizing with a spheroidizing agent, the spheroidizing of the graphite does not proceed sufficiently, and the spheroidizing is insufficient and poor spheroidizing. Is a typical example, and it is sometimes difficult to distinguish the shape from massive graphite.

  According to the cast iron-based soft magnetic material according to aspect 7, when the cast iron-based soft magnetic material is defined as 100%, silicon is included at 1.0 to 10% and carbon is included at 1.8 to 4.3%. ing. Silicon promotes ferritization and can increase the permeability of cast iron soft magnetic material, but if it is excessive, the hardness will be high, and post-processing such as cutting will be difficult, and hot water will be difficult. Flowability also decreases, and a tendency for castability to decrease is observed. The amount of silicon can be increased when post-workability, castability, etc. are not a problem. Taking these into consideration, the lower limit side can be exemplified as 1.1% or more, 1.2% or more, 1.3% or more, and the upper limit side is 4% or less, 5% or less, 6% or less, Can be exemplified by 8% or less, but is not limited thereto. Accordingly, examples of the silicon amount include 1.1 to 8%, 1.2 to 6%, and 1.2 to 5%.

  Since silicon can promote ferritization and contribute to increase the magnetic permeability of the cast iron soft magnetic material, the silicon amount can be substantially the same as the carbon amount or larger than the carbon amount by weight ratio. Accordingly, the silicon amount / carbon amount by weight ratio may be 0.95 or more, 1 or more, 1.2 or more, 1.8 or more, or 2.0 or less. When a soft magnetic material is formed of a laminated body of silicon steel plates, the silicon steel plate becomes harder as the amount of silicon increases, and the press punching property decreases when the silicon steel plate is press punched. As long as it is a cast iron-based soft magnetic material that solidifies the molten metal, press punchability need not be considered.

  Since carbon lowers the solidification start temperature of the molten metal, the flowability of the molten metal is improved to improve the castability. However, if carbon is excessive, there is a risk of impairing the magnetic permeability. Therefore, preferably, the carbon content can be set to 1.8 to 4.3% by weight. In this case, with respect to the carbon content, the lower limit side can be exemplified as 1.8% or more, 1.9% or more, 2.0% or more, and the upper limit side is 4.2% or less, 4.0% or less. , 3.8% or less, and further 3.6% or less, and therefore the carbon content is 1.8-4.2%, 1.8-4.0%, 1.8-3.8%. Can be illustrated. However, it is not limited to these.

  The cast iron soft magnetic material according to the present invention preferably contains a carbon amount and a silicon amount having a CE value of 2 or more. Thereby, good castability, magnetic characteristics, etc. are obtained. The CE value is a carbon equivalent, and the CE value is determined by the following formula (1).

CE value = carbon content (wt%) + silicon content (wt%) x 1/3 (1 formula)
The cast iron soft magnetic material according to the present invention may be used after heat treatment, or may be used without heat treatment. When used without heat treatment, the CE value can be increased in order to ensure the ferrite area ratio in the as-cast state. The CE value varies depending on the presence or absence of heat treatment, the use of cast iron soft magnetic material, the material, the amount of other alloy elements, the required strength, the cost, etc., but the lower limit of the CE value is 2.2 or more. 5 or more, or 3 or more can be exemplified, and the upper limit side can be exemplified by 6 or less and 5.5 or less. Accordingly, any of a hypoeutectic region, a eutectic region, and a hypereutectic region may be used.

  The cast iron soft magnetic material of the present invention can be used as a magnetic path forming material. In particular, it can be used as a magnetic path forming material for electromagnetic actuators such as motors and electromagnetic valves. For motors, it can be used for rotor cores, stator cores, and the like. As the motor, various motors such as an ABS system motor, a power steering motor, a wiper motor, a window regulator motor, a door lock motor, and a sunroof motor can be used, but are not limited thereto. .

 According to the present invention, it is possible to provide a cast iron-based soft magnetic material that is advantageous for reducing iron loss while ensuring magnetic flux density.

  Examples of the present invention will be specifically described below together with comparative examples.

(Example 1)
High-purity pig iron (carbon content: 4.0 wt%) by weight 6 kg, steel (S10C) by weight 19 kg, carburizing agent (carbon content: 70 wt%) by weight 1210 g, ferrosilicon (silicon-containing) 1800 g by weight and 1060 g by weight of ferrovanadium (FeV) were weighed at 1450 to 1600 ° C. in a high-frequency melting furnace. This dissolved hot water was used as a source hot water.

  In the crucible, 350 g by weight of spheroidizing treatment agent (TDCR-5 / Mg: 4.8 wt%, silicon: 46 wt%, Ca: 2.4 wt%, balance: Fe) manufactured by Toyo Denka Co., Ltd., ferrosilicon (silicon content) 70 wt%, balance Fe) 70 g by weight was added, and the spheroidizing agent was covered with 100 g of iron powder.

  Thus, 1600 degreeC hot water was poured in the crucible which accommodated the spheroidizing agent, and the process for spheroidizing was performed.

  Thereafter, the molten metal after spheroidizing treatment was poured into a cavity of a mold as a mold (self-hardening sand mold, using alkali phenol as a binder). The pouring temperature was 1450 ° C. At the time of pouring, pouring was inoculated using an inoculum (Carbaloy (iron-silicon system) made by Osaka Special Alloy).

  After pouring into the mold for a predetermined time (1 hour), the mold was disintegrated and the solidified casting was taken out. The cavity of the mold (sand mold) was formed in a cylindrical shape so that a test piece for magnetic properties of the material, an iron core for a motor, and electricity measurement could be taken. The diameter of the columnar shape was 60 mm and the length was 200 mm. The test piece is used in an as-cast state without heat treatment.

  By the above method, cast iron-based soft iron is produced by spheroidal graphite cast iron containing carbon: 3.6%, silicon: 4.87%, vanadium: 2.03% by weight, with the balance being substantially iron and inevitable impurities. A magnetic material was formed. Manganese contains about 0.2 to 0.6% by weight and unavoidable phosphorus and sulfur.

  A ring-shaped test piece for measuring magnetic properties was cut out from this sample by cutting, and the test pieces were annealed (1000 ° C. × 5 hours), and AC magnetic properties were measured. For the magnetic property measurement, Iwasaki Tsushinki Co., Ltd. BH Analyzer SY-8232 was used, and measurement was performed under the conditions of an AC frequency of 400 Hz and a magnetic field of 10,000 A / m. The variation in the magnetic characteristic value of the measuring device during AC measurement was within 1%.

  DC magnetic properties were also tested. In this case, measurement was performed under the condition of a magnetic field of 10,000 A / m using a direct current BH characteristic device BHU-60 manufactured by Riken Denshi Co., Ltd. The variation in the magnetic characteristic value of the measuring device during direct current measurement was within 1%.

(Example 2)
A cast iron-based soft magnetic material containing carbon: 2.11% by weight, silicon: 3.91%, vanadium: 0.99%, and the balance substantially consisting of iron was obtained in the same manner as in Example 1. Produced.

(Example 3)
A cast iron-based soft magnetic material containing carbon: 2.0%, silicon: 1.5%, vanadium: 0.49% by weight, and the balance being substantially made of iron in the same manner as in Example 1. Produced.

Example 4
A cast iron-based soft magnetic material containing, by weight, carbon: 2.01%, silicon: 1.66%, vanadium: 0.535%, boron: 0.05%, the balance being substantially iron The same method as in Example 1 was used. In this case, ferroboron (FeB) powder was used and inoculated with ferrosilicon at the time of molten metal flow inoculation.
A cast iron soft magnetic material was formed under the conditions shown in Table 1, and the magnetic properties were measured.

  Further, an adhesion test was performed on the cast iron soft magnetic material according to Examples 3 and 4 and the cast iron soft magnetic material according to Comparative Example 3, and the friction characteristics were tested. In this case, using a Suzuki-type friction and wear evaluation tester, a ring-shaped mating material (pure iron nitriding material) and a plate-shaped test piece (present invention material) were combined, and a surface pressure of 2 MPa was applied. The state was slid for 0.5 hours. At that time, the presence or absence of adhesion and the friction coefficient were tested. The adhesion state was observed with a stereoscopic microscope and an electron microscope. The measurement results are shown in Table 1.

  Table 1 described above shows the measurement results for the composition, CE value, β value (β value = Cwt% + Siwt%), castability, presence / absence of spheroidizing treatment, magnetic characteristics, and the like for each sample.

  As shown in Table 1, according to Examples 1 to 4, carbon is 2.0 to 3.6% by weight, silicon is 1.5 to 4.87% by weight, and vanadium is The weight ratio is 0.49 to 2.03%, the CE value is 2.5 to 5.22, and the β value is 3.5 to 8.47%.

(Evaluation)
As shown in Table 1, with respect to the evaluation of castability, Example 1 and Comparative Example 1 with a large amount of carbon were ◎, and others were ○. Regarding magnetic characteristics, according to each example, improvement of magnetic flux density and reduction of volume iron loss are recognized by adding vanadium. According to the present embodiment, most of the iron-based matrix of the cast iron-based soft magnetic material is a ferrite-based ferrite, and granular graphite and granular vanadium carbide are dispersed in the iron-based matrix. It is considered that vanadium carbide is produced by vanadium as a nucleus when the molten cast iron is cooled. For this reason, it is speculated that the magnetic flux density of the cast iron soft magnetic material can be increased by adding vanadium. Although the magnetic flux density is converted into force, it works as the square of the magnetic flux density, so even if the magnetic flux density is a difference of several percent, it appears as a large difference in the cast iron soft magnetic material product.

  Here, it can be determined that the compositions of Example 1 and Comparative Example 1 are approximately similar except for vanadium. In this case, Example 1 containing vanadium has higher DC magnetic flux density and AC magnetic flux density than Comparative Example 1 containing no vanadium, and also has less volume iron loss.

  It can be judged that the compositions of Example 2 and Comparative Example 2 are approximately similar except for vanadium. In this case, Example 2 containing vanadium has a higher DC magnetic flux density and AC magnetic flux density than Comparative Example 2 containing no vanadium, and also has a lower volume iron loss.

  It can be judged that the compositions of Example 3 and Comparative Example 3 are approximately similar except for vanadium. In this case, Example 3 containing vanadium has higher DC magnetic flux density and AC magnetic flux density than Comparative Example 3 not containing vanadium, and also has less volume iron loss.

  Moreover, it can be judged that the compositions of Example 4 and Comparative Example 3 are approximately similar except for vanadium and boron. In this case, Example 4 containing vanadium and boron has higher DC magnetic flux density and AC magnetic flux density than Comparative Example 3 containing no vanadium and boron, and also has a smaller volume iron loss.

  Note that Comparative Example 4 is not spheroidized and does not contain vanadium. In Comparative Example 4, although the volume iron loss can be made lower, the DC magnetic flux density and the AC magnetic flux density are also lower, which is not always sufficient.

  Add a description of the adhesion test. No adhesion was observed for Example 3 containing vanadium and Example 4 containing vanadium and boron. However, in Comparative Example 3, adhesion was observed. In cast iron containing vanadium, vanadium exists as a VC carbide, and unlike graphite, it is not only hard, but also the gap is suppressed and the adhesion to the matrix is high. This is presumed to be because powder does not easily occur. The coefficient of friction of Example 3 and Comparative Example 3 was 0.4. The coefficient of friction of Example 4 containing vanadium and boron was somewhat high, 0.5. This is presumably because the FeB compound is present at the grain boundaries, so that the sliding resistance is slightly increased and the friction coefficient is increased.

(EPMA analysis of Example 1)
1 shows a photomicrograph showing the metal structure of a cast iron soft magnetic material according to Example 1. FIG. As shown in FIG. 1, it can be seen that spherical graphite and polymorphic graphite that is deformed by breaking the spherical graphite are dispersed in the iron matrix.

  2 to 4 show element distribution states of EPMA analysis. FIG. 2 shows the distribution state of carbon. FIG. 3 shows the distribution of silicon. FIG. 4 shows the distribution state of vanadium. As can be understood from FIG. 2, it can be seen that spherical graphite or multi-shaped graphite in which spherical graphite is deformed and deformed is dispersed in the iron-based matrix. As can be seen from FIG. 3, silicon is dispersed throughout the iron matrix. This means that the entire ferritic iron-based matrix dissolves silicon. 4 and 2 together, it can be seen that carbon is present at the position where vanadium is present. This shows that vanadium carbide (VC) in which vanadium and carbon are bonded is generated and dispersed in the iron-based matrix.

  As can be understood from the above description, according to the present embodiment, the specific resistance of the cast iron soft magnetic material is increased, and therefore the iron loss can be reduced while ensuring the magnetic flux density. In addition, according to the present embodiment, the melted molten metal is cast and solidified in a mold cavity such as a mold, so that the moldability is good and the three-dimensional shape or complicated shape is obtained. Even so, there is an advantage that it can be formed easily while suppressing the cost. Furthermore, it is formed by casting the molten metal into a mold cavity such as a mold and solidifying it, so it has high integrity, and there is little change in strength and magnetic properties even in high temperature environments or environments with temperature changes. Therefore, it can be used satisfactorily even in an environment where the use temperature may be high, such as a vehicle. Furthermore, according to the cast iron-based soft magnetic material according to the present example, since a large number of graphite is generated in the iron-based matrix, even if it is used in an environment where vibration acts, vibration damping properties are also ensured.

(Other)
In addition, the present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications within a range not departing from the gist. The following technical idea can be understood from the above description.
(Additional Item 1) A cast iron system having a ferritic iron-based matrix and having a carbide produced by a carbide-forming element dispersed in the ferritic iron-based matrix and formed by casting (molten solidification) Soft magnetic material. Since carbon contained in the iron-based matrix is consumed by the carbide-generating element to generate carbide, the amount of carbon in the iron-based matrix can be reduced, and the composition of the iron-based matrix can be brought close to the pure iron composition.
(Additional Item 2) A step of adding a carbide generating element to a molten metal having a cast iron composition, a molten cast iron composition to which the carbide generating element is added is poured into a mold cavity, solidified, and used as a soft magnetic material after cooling. A method for producing a cast iron-based soft magnetic material. Since carbon contained in the iron-based matrix is consumed by the carbide-generating element to generate carbide, the amount of carbon in the iron-based matrix can be reduced, and the composition of the iron-based matrix can be brought close to the pure iron composition.

  The present invention can be applied to, for example, a magnetic circuit member installed in an electronic device, an electric device, or the like. Specifically, for example, it can be applied to a magnetic circuit member such as an iron core equipped in a motor, an electromagnetic actuator, or the like.

2 is a photomicrograph showing the metal structure of a cast iron soft magnetic material according to Example 1; It is a photograph which shows the analysis result of carbon by EPMA about the cast iron type soft magnetic material which concerns on Example 1. FIG. It is a photograph which shows the analysis result of the silicon | silicone by EPMA about the cast iron type soft magnetic material which concerns on Example 1. FIG. It is a photograph which shows the analysis result of vanadium by EPMA about the cast iron type soft magnetic material which concerns on Example 1. FIG.

Claims (7)

  A cast iron-based soft magnetic material having a ferrite-based iron-based matrix and having carbides generated by a carbide-forming element dispersed in the ferrite-based iron-based matrix.   The cast iron soft magnetic material according to claim 1, wherein the carbide is granular.   3. The cast iron-based soft magnetic material according to claim 2, wherein the carbide is granular with an average particle size of 100 μm or less.   In any one of Claims 1-3, the said carbide | carbonized_material production | generation element is at least 1 sort (s) of vanadium, tungsten, molybdenum, titanium, and the said carbide | carbonized_material is vanadium carbide, tungsten carbide, molybdenum carbide, titanium carbide. A cast iron-based soft magnetic material characterized by being at least one of them.   5. The cast iron soft magnetic material according to claim 4, wherein when the cast iron soft magnetic material is 100%, the carbide generating element is contained by 8% or less by weight.   6. The graphite according to claim 1, wherein the graphite is dispersed in the ferritic iron-based matrix, and the graphite is spheroidal graphite, CV graphite (compact vermicular graphite), piece A cast iron-based soft magnetic material characterized by existing in the form of at least one of glassy graphite, massive graphite, multi-shaped graphite, rose graphite, and eutectic graphite.   In any one of Claims 1-6, when a cast iron type soft magnetic material is 100%, silicon is 1.0 to 10% and carbon is 1.8 to 4.3 by weight ratio. % Cast iron-based soft magnetic material.

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