JP2008169451A - Component made of electrical sheet having excellent magnetic property, bar wire rod for component made of electrical sheet, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a component made of an electrical sheet such as a solenoid, to provide a steel member for a component made of an electrical sheet having excellent magnetic properties and used as the stock for the electrical sheet component, particularly, to provide a bar wire rod for a component made of an electrical sheet, and to provide a method for producing the same. <P>SOLUTION: The electrical sheet component having excellent magnetic properties has a composition comprising, by mass, >0.20 to 0.50% Mn, further comprising either or both of 0.05 to 1.00% Ni and 0.05 to 1.00% Co, and in which the content of C is limited to ≤0.02%, Si to ≤0.10%, P to ≤0.010% (inclusive of 0%), S to ≤0.010% (inclusive of 0%), Total Al to ≤0.010% (inclusive of 0%), Sol.Al to ≤0.005% (inclusive of 0%), Ti to ≤0.005%, N to ≤0.0050% and O to 0.0200%, and the balance Fe with inevitable impurities, and has the ferrite grain size number of ≤5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electromagnetic soft iron part such as a solenoid, a steel material for an electromagnetic soft iron part which is a material of the electromagnetic soft iron part, and a method for manufacturing the same.

  Steel materials for electromagnetic soft iron parts, especially rod wires for electromagnetic soft iron parts, are used as soft magnetic materials, for example, electric parts for automobiles, industrial equipment, automatic transmissions, electromagnetic clutches, etc. It is mainly used as a material for equipment, that is, electromagnetic soft iron parts. In recent years, electronic control parts used in automobiles are increasing, and high performance and downsizing of electromagnetic soft iron parts are required. Therefore, higher performance is also required for the magnetic properties of the bar wire for electromagnetic soft iron parts. The magnetic properties required for this soft magnetic material are a high magnetic flux density generated with respect to an external magnetic field (high magnetic flux density) and a small hysteresis loss (low coercive force) to reduce power consumption. That is, a material having a small coercive force (Hc) and a large saturation magnetic flux density (Bm) is required in a change curve (so-called hysteresis curve) of the magnetic flux density accompanying the strength of the magnetic field.

  Pure iron-based soft magnetic materials have been proposed as materials for electromagnetic parts that meet such requirements. In general, the following measures are taken to improve the magnetic properties of pure iron-based soft magnetic materials. (1) To obtain a high magnetic flux density, the amount of C in iron and the amount of alloying elements are reduced as much as possible, and (2) the ferrite crystal grains are enlarged to obtain a low coercive force. (3) To reduce the lattice defect density and the amount of crystal precipitates to facilitate magnetic domain movement.

  For example, soft magnetic steel has been proposed in which the amount of C is significantly reduced to form a ferrite single phase structure, and Al and N are reduced to suppress crystal grain non-uniformity (for example, Patent Document 1, Non-Patent Document). 1). The electromagnetic parts and soft magnetic materials proposed in Patent Document 1 and Non-Patent Document 1 are made by detoxifying S by adding Mn and growing ferrite crystal grains by annealing after cold working to reduce the coercive force. It is. Non-Patent Document 1 shows that when the ferrite crystal grain size is as coarse as 4 or less, the coercive force is drastically reduced and good magnetic flux density characteristics can be obtained.

  However, in order to improve the magnetic characteristics beyond the conventional level, it is necessary to significantly reduce the amounts of C, Al, and N to the limit as compared with the conventional level. For this reason, with the refining ability of the current steelmaking factory premised on mass production, there has been a problem that it is extremely difficult to reduce the above components to the limit, and even if it can be produced, the production cost becomes very high.

  In order to improve magnetic properties, a thick steel plate has been proposed by dehydrogenation treatment and addition of Ni (for example, Patent Document 2). Patent Document 2 also discloses that the effect of crystal grain refining by AlN is harmful to magnetic properties. However, the thick steel plate proposed in Patent Document 2 uses Al as a deoxidizing agent, and does not describe a method for manufacturing a bar wire.

JP 2003-226946 A JP-A-4-268822 Masamichi Chiba, Masato Shikabe, “Pure Iron-Based Soft Magnetic Materials”, Kobe Steel Technical Report, Vol. 52, No. 3, December 1, 2002, issued by Kobe Steel, p. 66-69

  In view of the above-described problems, the present invention is an electromagnetic soft iron component such as a solenoid, a steel material for an electromagnetic soft iron component excellent in magnetic properties, particularly a rod for an electromagnetic soft iron component, used as a material for the electromagnetic soft iron component. The object is to provide a wire rod and a manufacturing method thereof.

  The present invention relates to an electromagnetic soft iron part that improves magnetic properties by adding one or both of Ni and Co, and further suppresses deterioration of magnetic properties caused by a texture formed in a rod and wire by hot rolling, and its electromagnetic A steel material for electromagnetic soft iron parts having excellent magnetic properties, which is used as a raw material for soft iron parts, and a method for producing the same, the summary of which is as follows.

(1) In mass%,
Mn: more than 0.20 to 0.50%
In addition,
Ni: 0.05-1.00%,
Co: 0.05-1.00%
One or both of
C: 0.02% or less,
Si: 0.10% or less,
P: 0.010% or less (including 0%),
S: 0.010% or less (including 0%),
Total Al: 0.010% or less (including 0%),
Sol. Al: 0.005% or less (including 0%),
Ti: 0.005% or less (including 0%),
N: 0.0050% or less,
O: 0.0200%
An electromagnetic soft iron part with excellent magnetic properties, characterized in that the balance is Fe and inevitable impurities, and the ferrite grain size number is 5 or less.

(2) the ratio of the axial cross ferrite grain size number of _{G L} and the axial direction perpendicular to the direction of the cross ferrite grain size number _{G C G} L / _{G C,} characterized in that a 0.80 to 1.20 An electromagnetic soft iron part having excellent magnetic properties as described in (1) above.

(3) The material of the electromagnetic soft iron part described in (1) above, in mass%,
Mn: more than 0.20 to 0.50%
In addition,
Ni: 0.05-1.00%,
Co: 0.05-1.00%
One or both of
C: 0.02% or less,
Si: 0.10% or less,
P: 0.010% or less (including 0%),
S: 0.010% or less (including 0%),
Total Al: 0.010% or less (including 0%),
Sol. Al: 0.005% or less (including 0%),
Ti: 0.005% or less (including 0%),
N: 0.0050% or less,
O: 0.0200%
The wire rod for electromagnetic soft iron parts excellent in magnetic properties, characterized in that the balance is made of Fe and inevitable impurities.

(4) above a material of an electromagnetic soft iron component according to (2), the ratio G _{R /} G of the ferrite grain size number G _T of the ferrite grain size number G _R to the rolling direction in the vertical direction of the cross section of the rolling direction cross-section _The wire rod for electromagnetic soft iron parts having excellent magnetic properties as described in (3) above, wherein _T is 0.80 to 1.20.

(5) A method for producing a bar wire for electromagnetic soft iron parts as described in (3) above, in mass%,
Mn: more than 0.20 to 0.50%
In addition,
Ni: 0.05-1.00%,
Co: 0.05-1.00%
One or both of
C: 0.02% or less,
Si: 0.10% or less,
P: 0.010% or less (including 0%),
S: 0.010% or less (including 0%),
Total Al: 0.010% or less (including 0%),
Sol. Al: 0.005% or less (including 0%),
Ti: 0.005% or less (including 0%),
N: 0.0050% or less,
O: 0.0200%
A method for producing a bar wire material for electromagnetic soft iron parts excellent in magnetic properties, characterized in that a rolled material consisting of Fe and inevitable impurities is hot-rolled.

  (6) The bar wire for electromagnetic soft iron parts having excellent magnetic properties as described in (5) above, wherein the rolled material is heated to 1000 ° C. to 1250 ° C. and hot rolled at a finishing temperature of 800 ° C. or higher. Manufacturing method.

  (7) A method for manufacturing a bar wire for electromagnetic soft iron parts as described in (4) above, wherein after the hot rolling, heat treatment is performed by heating to a temperature range of 880 to 1250 ° C., holding for 60 to 3600 s, and cooling. The manufacturing method of the bar wire for electromagnetic soft iron parts excellent in the magnetic characteristics as described in said (5) or (6) characterized by performing.

  (8) The method for producing a bar wire for electromagnetic soft iron parts having excellent magnetic properties according to (7) above, wherein the cooling rate after heating and holding is 0.1 to 5 ° C./s.

  According to the rod and wire material for electromagnetic soft iron parts excellent in magnetic characteristics of the present invention and the manufacturing method thereof, the direct current magnetic characteristics of electromagnetic soft iron parts such as solenoids are improved. Industrial contributions such as automatic transmissions and electromagnetic clutches with high performance and miniaturization are very significant.

The present inventors diligently studied various factors affecting the magnetic characteristics of electromagnetic soft iron parts and bar wires for electromagnetic soft iron parts, and found the following findings. That is,
(1) In order to reduce the coercive force, it is necessary to facilitate the movement of magnetic domains. For this purpose, it is necessary to reduce the grain boundaries, inclusions, and crystal precipitates that hinder magnetic domain movement. It is effective to reduce objects and inclusions as much as possible.
(2) Among the elements (Al, Ti, N, S, O) that form particles (various alloy carbonitrides, sulfides, oxides, etc.) that pin the crystal grains, especially ferrite grains are refined It is necessary to regulate the amount of Al (particularly the amount of Sol.Al) that forms AlN, which has a large effect.
(3) When the amount of Mn is extremely reduced, part of MnS is dissolved in the matrix during rolling and heating, and MnS is refined by reprecipitation during the subsequent cooling process or heat treatment. is necessary.
(4) Ni and Co increase the saturation magnetic flux density of iron and do not generate carbonitrides and sulfides in iron, so they do not adversely affect the coercive force, so they are extremely effective means for improving magnetic properties. is there.
(5) In particular, when hot rolling is performed on the shape of a steel bar or wire rod, the anisotropy (texture) of the crystal orientation due to rolling is inherited to the final product, which adversely affects the magnetic properties. That is, when manufacturing steel bars and wire rods by hot rolling, the ferrite crystal grain size observed in the rolling direction (R direction) section is observed in the section perpendicular to the rolling direction (T direction). The crystal grain size tends to be smaller. As a result, anisotropy of magnetic properties due to the texture is generated in the electromagnetic soft iron part, which is the final product manufactured by cold forging, cutting, and final annealing of the bar wire. In order to prevent this, it is preferable that the ratio of the ferrite grain size in the axial direction (L direction) and the direction perpendicular to the axial direction (C direction) of the electromagnetic soft iron part is close to 1. For this purpose, it is effective to reduce the crystal orientation anisotropy by subjecting the rod-and-wire material after hot rolling to a temperature range in which the structure becomes an austenite single phase.

  Hereinafter, the present invention will be described in detail. First, the components of the electromagnetic soft iron part and the bar wire for the electromagnetic soft iron part of the present invention will be described.

  Mn: Mn needs to be 0.50% or less in order to reduce the saturation magnetic flux density of iron. On the other hand, Mn combines with S in steel to form MnS, thereby pinning the growth of crystal grains and having the effect of refining the crystal grains. For this reason, when the amount of Mn added is reduced to 0.20% or less, a part of MnS is dissolved in the matrix during rolling and heating, and MnS is finely re-precipitated during the subsequent cooling process or heat treatment, so that the crystal grains are more It becomes fine and the holding power increases. Therefore, in order to suppress the decrease of the saturation magnetic flux density of the electromagnetic soft iron part and its material and prevent the refinement of crystal grains due to the fine precipitation of MnS, it is necessary to be in the range of more than 0.20 to 0.50%. There is. In addition, since the hardness of a raw material raises and cold workability also falls by addition of Mn, it is preferable to reduce Mn to 0.30% or less.

  Ni and Co: Ni and Co are elements that increase the saturation magnetic flux density, and do not produce carbonitrides and sulfides in the steel, and thus do not adversely affect the coercive force. Therefore, it is an element that is extremely effective in improving the magnetic properties of electromagnetic soft iron parts and their materials. On the other hand, since excessive addition may not only saturate the effect but also decrease the magnetic properties, it must be in the range of 0.05 to 1.00%. A preferable range is 0.05 to 0.30%. In the present invention, Ni and Co are extremely important elements, and it is necessary to add one or both in the range of 0.05 to 1.00%.

  C: C forms cementite in the steel, thereby decreasing the saturation magnetic flux density and increasing the coercive force. Therefore, it is necessary to reduce the C content to 0.02% or less. Moreover, since the hardness of a raw material raises by containing C and cold workability falls, it is preferable to reduce as much as possible, However, In order to reduce C, the cost on refining starts. A suitable upper limit is 0.01% or less.

  Si: Si lowers the saturation magnetic flux density, and the cold workability decreases as the material hardness increases, so it is necessary to reduce it to 0.10% or less. In addition, in the case of electromagnetic soft iron parts that are assumed to be used in direct current, it is not necessary to consider the reduction of eddy current loss, so the preferred range is 0.05% or less.

  P: P is an element that decreases the cold workability, and needs to be reduced to 0.010% or less (including 0%). The preferred range is 0.008% or less.

  S: S is inevitably contained, and is an element having an effect of refining crystal grains by combining Mn in steel to form MnS, pinning the growth of crystal grains, and 0.010% (It is necessary to make it 0%. Therefore, when S is present, it is necessary to reduce the amount of Mn added to 0.010% or less. In order to reduce the coercive force, the amount of Mn is set to 0.008. % Or less is preferable.

Total Al: Al forms inclusions such as Al ₂ O ₃ that acts as a barrier for magnetic domain movement. Therefore, if Al is contained excessively, the coercive force increases, and the inclusions become the starting point of fracture during cold working. Cold workability decreases. Therefore, it is necessary to reduce the total Al amount to 0.010% or less (including 0%). Further, Al dissolved in the steel combines with N in the steel to form AlN and pin the growth of crystal grains. Since AlN has a great effect of refining crystal grains, the coercive force is increased and the magnetic properties are deteriorated. Therefore, it is preferable that the total Al amount is 0.005% or less. Total Al is the total amount of Al contained in the steel, and is the total of the amount of solid solution in the steel and the amount existing as inclusions such as oxides.

  Sol. Al: Al dissolved in the steel generates AlN as described above, refines the crystal grains, and greatly reduces the magnetic properties. In particular, from the viewpoint of AlN reduction, Sol. Since it is effective to regulate the amount of Al, Sol. The amount of Al needs to be reduced to 0.005% or less (including 0%). The preferred range is 0.003% or less. In addition, Sol. Al is a solid solution amount excluding Al present as inclusions such as oxides in steel, and can be measured by electrolytic extraction residue analysis.

  Ti: Ti is an element that forms TiN. When excessively added, coarse TiN is generated, which becomes a starting point of fracture during cold working, and cold workability is lowered. Therefore, the amount of Ti needs to be reduced to 0.005% or less (including 0%). Further, when Ti produces fine TiN like AlN, the crystal grains become fine and the magnetic properties are deteriorated. Therefore, the Ti content is preferably 0.003% or less.

  N: N combines with Al and N in steel to form AlN and TiN having an effect of refining crystal grains. Thereby, since the coercive force is increased, the N amount needs to be reduced to 0.0050% or less. The preferred range is 0.0030% or less.

  O: O is an element that forms an oxide with Al, Si, Ti and the like in steel. These oxides are inclusions that serve as barriers for magnetic domain movement, and not only increase the coercive force, but also the inclusions become the starting point of breakage during cold working, resulting in a decrease in cold workability. It is necessary to reduce to the following. The preferred range is 0.0150% or less.

  Next, the structure of the electromagnetic soft iron part of the present invention will be described.

  Ferrite grain size number: In the present invention, when the crystal grain size is refined, the magnetic properties are lowered, so the ferrite grain size number needs to be 5 or less. The ferrite particle size number can be measured by a comparison method or a cutting method in accordance with JIS G 0551. In addition, what is necessary is just to extract | collect the sample which measures a ferrite particle size by making a measurement surface into arbitrary directions. For example, it may be either the axial direction (L direction) or the direction perpendicular to the axial direction (C direction).

  When the electromagnetic soft iron part is rod-shaped, its axial direction corresponds to the longitudinal direction of the bar wire, that is, the rolling direction (R direction), and the direction perpendicular to the axial direction of the electromagnetic soft iron part is This corresponds to the direction perpendicular to the rolling direction (T direction).

  In addition, when the electromagnetic soft iron part has a flat plate shape, a bar wire is often cold forged parallel to the rolling direction, so the thickness direction is the axial direction and the horizontal direction is the direction perpendicular to the axial direction. Define. Therefore, a flat electromagnetic soft iron part such as a disk or a ring may have a thickness direction that is the R direction of a bar wire that is a material or a T direction. When the thickness direction corresponds to the R direction of the material, the horizontal direction corresponds to the T direction, and when the thickness direction corresponds to the T direction of the material, the horizontal direction corresponds to the R direction of the material.

  Furthermore, even when the electromagnetic soft iron part has a cup shape composed of a bottom and a vertical wall, the bar wire is often cold forged in parallel with the rolling direction, as in the flat plate shape. Is defined as the axial direction, and the direction parallel to the bottom is defined as the direction perpendicular to the axial direction. Therefore, in a cup-shaped electromagnetic soft iron part, there are cases where the depth direction of the cup is the R direction of the bar wire material, and the T direction. Among these, when the depth direction of the cup and the thickness direction of the bottom correspond to the R direction of the material, the direction parallel to the bottom corresponds to the T direction, and the depth direction of the cup and the thickness direction of the bottom correspond to the T direction of the material. When it corresponds to the direction, the direction parallel to the bottom corresponds to the R direction of the material.

In the present invention, the ratio G _L / G _C of the ferrite crystal grain size G _L in the axial direction and the ferrite crystal grain size G _{C in} the direction perpendicular to the axial direction of the electromagnetic soft iron part is preferably 0.80 to 1.20. . Thereby, the anisotropy of the magnetic property resulting from the texture formed by wire rod rolling is reduced, and the magnetic property is further improved.

  Next, a method for manufacturing the electromagnetic soft iron part of the present invention will be described.

  The steel composed of the above components is melted in a converter or electric furnace, and secondary refining and continuous casting are performed. The slab obtained by performing continuous casting may be used as a rolling material as it is, but it may be subjected to split rolling and used as a rolling material. The rolled material is heated to 1000 ° C. to 1250 ° C. and hot-rolled to obtain a bar or wire.

  The finishing temperature of hot rolling is preferably 800 ° C. or higher. Thereby, recrystallization of the rolled material is promoted, the anisotropy of the crystal orientation can be reduced, and the anisotropy of the ferrite crystal grain size of the final product is reduced. Cooling after rolling may be air cooling or slow cooling.

  A rod and wire obtained by hot rolling is processed into a part shape by one or both of cold processing such as forging and cutting. After processing to the part shape, final annealing is performed to remove the processing strain and recrystallize and grow the ferrite crystal grains to improve the magnetic properties. If the final annealing heating temperature is too low or the heating time is too short, the crystal grains may not grow sufficiently. On the other hand, if the heating temperature of the final annealing is too high or the heating time is too long, part of the structure becomes austenite, the crystal grain size becomes fine due to transformation, and the magnetic properties may deteriorate. Therefore, it is preferable that the heating temperature of the final annealing is 800 to 880 ° C. and the heating time is 1 to 10 hours. The cooling after the final annealing is preferably air cooling or slow cooling.

  The rod and wire manufactured by hot rolling may be cold worked as it is, or may be subjected to intermediate annealing for improving cold workability after hot rolling. Intermediate annealing is effective in eliminating texture anisotropy, and is effective in bringing the ratio of the grain size of the cross section perpendicular to the axial direction to the axial cross section of the electromagnetic soft iron part close to 1. If the heating temperature of the intermediate annealing is too low or the heating time is too short, softening may be insufficient. Moreover, when the heating temperature of intermediate annealing is too high or the heating time is too long, cementite may be re-dissolved in the matrix and finely precipitated during cooling, resulting in insufficient softening. Therefore, in order to sufficiently obtain the effect of the intermediate annealing, there are suitable heating temperature and heating time. In the case of the steel material of the present invention, it is preferable that the heating temperature is 650 to 720 ° C. and the heating time is 2 to 24 hours. The cooling after the intermediate annealing is preferably air cooling or slow cooling. In addition, although intermediate annealing is effective when the cold work rate is high, it does not necessarily need to be performed.

  In addition, what is applied to parts that require particularly excellent magnetic properties may be subjected to a heat treatment that is heated to a high temperature and transformed into an austenite single phase after hot rolling, before intermediate annealing and cold working. preferable. Thereby, the anisotropy of the texture produced by hot rolling can be eliminated.

  The structure of the wire for an electromagnetic soft iron part of the present invention, which is heat-treated after the hot rolling, will be described.

Ratio G _L / G _C of ferrite grain size number G _{L in} the cross section in the rolling direction and ferrite grain size number G _{C in} the cross section in the direction perpendicular to the rolling direction: of crystal orientation generated when hot rolling is performed on the shape of the bar steel and wire rod If the anisotropy is inherited to the final product, the magnetic properties are adversely affected. Therefore, the intermediate annealing, cold working before or after hot rolling of an electromagnetic soft iron component rod wire, the ratio of the ferrite grain size number G _T perpendicular cross section in the rolling direction and the ferrite grain size number G _R in the rolling direction cross-section G _R 1 / G _T is preferably as close to 1 as possible. Specifically, G _R / G _T is preferably 0.80 to 1.20.

In the electromagnetic soft iron part manufactured using this electromagnetic soft iron part wire, the ratio G _L / G _C of the ferrite grain size in the axial direction and the direction perpendicular thereto is 0.80 to 1.20. Thereby, the anisotropy of the magnetic characteristic resulting from the texture formed by hot rolling to the shape of a bar wire is reduced, and the magnetic characteristic of the electromagnetic soft iron part is further improved.

  Next, heat treatment after hot rolling will be described in the method for producing a bar wire for electromagnetic soft iron parts of the present invention.

  Heat treatment after hot rolling: In order to reduce the anisotropy of the texture of steel bars and wire rods after hot rolling, it is preferable that a part or all of the structure is once austenitized by heat treatment. If the heating temperature is too low or the holding time is too short, austenitization may be insufficient and the effect of reducing anisotropy may be insufficient. On the other hand, if the heating temperature is too high or the holding time is too long, the cost, facility restrictions, yield, etc. are reduced. Therefore, it is preferable to make heating temperature into the range of 880-1250 degreeC, and a more suitable range is 900-1100 degreeC. Further, the holding time is preferably 60 to 3600 s, and the preferable range of the holding time is 900 to 1800 s.

  In addition, when the cooling rate after heating and holding is too higher than 5 ° C./s, a bainite and martensite structure may be generated, and workability may be impaired. Further, when the cooling rate is too slower than 0.1 ° C./s, the productivity is lowered. Therefore, the cooling rate is preferably 0.1 to 5 ° C./s.

  In the method for manufacturing a bar wire for electromagnetic soft iron parts of the present invention, secondary processing such as wire drawing may be performed after hot rolling. In addition, when performing secondary processing in cold, for example, wire drawing, in order to improve cold workability, the material after hot rolling or heat treatment is subjected to annealing or spheroidizing annealing treatment. May be.

  Hereinafter, the present invention will be described in detail by way of examples.

  Converter molten steel having the composition shown in Table 1 was manufactured by continuous casting, and a rolling raw material of 162 mm square was obtained through a block rolling process. Next, a wire rod having a diameter of 25 mm was formed by hot rolling. Some rolled materials were heat-treated under the conditions shown in Table 2 after rolling.

  Next, the wire was held at 680 ° C. for 5 hours, then subjected to air-cooling intermediate annealing, a sample was taken, and Vickers hardness was measured according to JIS Z 2244. After cutting the wire after the intermediate annealing, 50% upsetting was performed at room temperature to simulate the cold forging process of component molding, and then a ring-shaped test piece (outer diameter 10 mm, inner diameter) as a test piece for magnetic property evaluation 6 mm, height 3 mm). Therefore, in the ring-shaped test piece, the thickness direction corresponds to the axial direction, and the horizontal direction corresponds to the direction perpendicular to the axial direction.

The ring-shaped test piece was heated to 850 ° C., held for 2 hours, and then subjected to final annealing for furnace cooling. Thereafter, the ferrite grain size number (G _L ) of the cross section in the axial direction and the ferrite grain size number (G _C ) of the cross section in the direction perpendicular to the axial direction were measured. Note that the wire material subjected to heat treatment after hot rolling, G ratio G _{R /} G _T of the ferrite grain size of a cross section perpendicular to the cross section to the rolling direction of the rolling direction of the wire is, the final annealing after the ring specimens It was confirmed to be equivalent to the _L / _{G C.}

  The DC magnetic characteristics of the ring-shaped test piece were measured by obtaining a hysteresis curve (BH curve) according to JIS C 2504 (IEC 60404-4). The coercive force (Hc) is measured under a magnetic field strength of 400 A / m applied and reversed. The magnetic flux density for an external magnetic field is the magnetic flux density (B) generated when the external magnetic field is 100 to 4000 A / m. did.

  The results are shown in Table 2. The measured value of the magnetic flux density represented the magnetic flux density (B1000) at 1000 A / m as a representative value. The criteria for superiority or inferiority of the magnetic properties were determined to be inferior in magnetic properties for Hc of 60 A / m or more and B1000 of 1.65 or less.

Production No. of the present invention example. 2 and 4 show the effect of heat treatment after rolling. Production Nos. Of the same component respectively. 1, no. 3 and by comparison, small ferrite grain size number, G L _/ G _C becomes closer to 1. That is, it can be seen that the ferrite grain size is increased and the anisotropy is improved, so that Hc is reduced and the magnetic properties are improved. In addition, production No. 3 is No.3. It is the same component as 1 and 2, and is an example of the present invention in which the heat treatment conditions after hot rolling are out of the preferred range. The magnetic characteristics of No. 3 are as follows. Is equivalent to 1.

  Production No. which is a comparative example. Since 12 to 17 do not contain Ni or Co, B1000 is smaller than the inventive examples and does not reach the target value. Production No. Since the amounts of Mn and Al are also outside the scope of the present invention in Nos. 15 to 17, the ferrite particle size number is large, and both Hc and B1000 are deteriorated.

  As is clear from these, those satisfying all the conditions defined in the present invention are superior in DC magnetic characteristics as compared with the comparative example.

Claims (8)

% By mass
Mn: more than 0.20 to 0.50%
In addition,
Ni: 0.05-1.00%,
Co: 0.05-1.00%
One or both of
C: 0.02% or less,
Si: 0.10% or less,
P: 0.010% or less (including 0%),
S: 0.010% or less (including 0%),
Total Al: 0.010% or less (including 0%),
Sol. Al: 0.005% or less (including 0%),
Ti: 0.005% or less (including 0%),
N: 0.0050% or less,
O: 0.0200%
An electromagnetic soft iron part with excellent magnetic properties, characterized in that the balance is Fe and inevitable impurities, and the ferrite grain size number is 5 or less. Claim ratio of axial sectional ferrite grain size number _{G L} and the axial direction perpendicular to the direction of the cross ferrite grain size number _{G C} of _G L / _{G C,} characterized in that a 0.80 to 1.20 1 Electromagnetic soft iron parts with excellent magnetic properties as described in 1. The material of the electromagnetic soft iron part according to claim 1, wherein the raw material is mass%.
Mn: more than 0.20 to 0.50%
In addition,
Ni: 0.05-1.00%,
Co: 0.05-1.00%
One or both of
C: 0.02% or less,
Si: 0.10% or less,
P: 0.010% or less (including 0%),
S: 0.010% or less (including 0%),
Total Al: 0.010% or less (including 0%),
Sol. Al: 0.005% or less (including 0%),
Ti: 0.005% or less (including 0%),
N: 0.0050% or less,
O: 0.0200%
The wire rod for electromagnetic soft iron parts excellent in magnetic properties, characterized in that the balance is made of Fe and inevitable impurities. A material of the electromagnetic soft iron component according to claim 2, the ratio G _{R /} G _T of the ferrite grain size number G _T of the ferrite grain size number G _R to the rolling direction in the vertical direction of the cross section of the rolling direction cross-section, 0 The bar wire material for electromagnetic soft iron parts having excellent magnetic properties according to claim 3, wherein the rod wire material has a magnetic property of .80 to 1.20. It is a manufacturing method of the bar wire material for electromagnetic soft iron parts of Claim 3, Comprising: In mass%,
Mn: more than 0.20 to 0.50%
In addition,
Ni: 0.05-1.00%,
Co: 0.05-1.00%
One or both of
C: 0.02% or less,
Si: 0.10% or less,
P: 0.010% or less (including 0%),
S: 0.010% or less (including 0%),
Total Al: 0.010% or less (including 0%),
Sol. Al: 0.005% or less (including 0%),
Ti: 0.005% or less (including 0%),
N: 0.0050% or less,
O: 0.0200%
A method for producing a bar wire material for electromagnetic soft iron parts excellent in magnetic properties, characterized in that a rolled material consisting of Fe and inevitable impurities is hot-rolled.   The method for producing a bar wire for an electromagnetic soft iron part having excellent magnetic properties according to claim 5, wherein the rolled material is heated to 1000 ° C. to 1250 ° C. and hot rolled at a finishing temperature of 800 ° C. or higher.   It is a manufacturing method of the bar wire material for electromagnetic soft iron parts of Claim 4, Comprising: After hot rolling, it heats to the temperature range of 880-1250 degreeC, and is heat-processed to hold | maintain and cool for 60-3600 s. The manufacturing method of the bar wire for electromagnetic soft iron parts excellent in the magnetic characteristics of Claim 5 or 6.   The method for producing a bar wire for an electromagnetic soft iron part having excellent magnetic properties according to claim 7, wherein the cooling rate after heating and holding is 0.1 to 5 ° C./s.