JP6623533B2 - Fe-based metal plate - Google Patents

Description

  The present invention relates to a high-strength Fe-based metal plate that is suitable for applications of magnetic cores having a large stress load used for electromagnetic components such as electric motors, generators, and transformers, and that can contribute to downsizing and reducing energy loss of these magnetic cores. .

  Conventionally, silicon steel plates have been used for magnetic cores of electric motors, generators, transformers and the like. The characteristics required for the silicon steel sheet are that the magnetic energy loss (iron loss) is small in an alternating magnetic field, and that the magnetic flux density is high in a practical magnetic field. To realize these, it is effective to increase the electric resistance and integrate the <100> axis of the α-Fe phase, which is the direction of easy magnetization, in the direction of the magnetic field to be used.

  In particular, when the {100} plane of the α-Fe phase is highly integrated in the rolling plane, the <100> axis becomes integrated in the rolling plane, and a higher magnetic flux density can be obtained when the same magnetic field is applied. Therefore, various techniques have been developed for the purpose of highly integrating the {100} plane parallel to the silicon steel sheet.

The present inventors have previously proposed the following technology as Patent Document 1.
(A) attaching a ferrite-forming element to one or both surfaces of a base metal plate made of an α-γ transformation type Fe-based metal;
(B) heating the base metal plate from room temperature to point A3 of the base metal plate to diffuse the ferrite-forming element into the base metal plate, partially alloying the base metal with the base metal, and The {200} plane integration degree of the α-Fe phase in the region of 25% to 50% and the {222} plane integration degree of 40% or less,
(C) Heating and holding the base metal plate at a temperature of A3 point or higher, increase the {200} plane integration degree of the α-Fe phase alloyed with the ferrite-forming element and increase the {222}工程 a process of reducing the degree of surface integration;
(D) When the base metal plate is cooled to a temperature lower than the A3 point and the γ-Fe phase in the unalloyed region transforms to the α-Fe phase, the {200} plane integration of the α-Fe phase A {200} plane integration degree of 30% or more and 99% or less, and a {222} plane integration degree of 30% or less. A method for producing an Fe-based metal plate having a high degree of integration.

  On the other hand, with the development of the motor drive system, frequency control of the drive power supply has become possible, and the number of motors that perform variable-speed operation and high-speed rotation at a commercial frequency or higher is increasing. In a motor that performs such high-speed rotation, the centrifugal force acting on a rotating body such as a rotor increases in proportion to the radius of rotation and increases in proportion to the square of the rotation speed. It is necessary that the magnetic core used for (1) have high strength.

  Under such circumstances, the Fe-based metal plate disclosed in Patent Literature 1 is also desired to have higher strength. However, Patent Literature 1 does not specifically study the enhancement of the strength of the Fe-based metal plate. .

  Generally, as a method for increasing the strength of a steel sheet, solid solution strengthening, precipitation strengthening, grain refinement strengthening, composite structure strengthening, and the like are known.However, there is a conflicting relationship between high mechanical strength and magnetic properties. It was extremely difficult to satisfy at the same time. 2. Description of the Related Art In recent years, a technique has been proposed for electrical steel sheets that achieves both high mechanical strength and magnetic properties.

  For example, Patent Literature 2 discloses a technique that utilizes precipitation hardening and grain hardening by carbonitrides of Nb, Zr, Ti, and V in a steel having a Si content of 2.0% or more and less than 4.0%. Proposed. Patent Literature 3 proposes a technique that utilizes refinement of crystal grains by precipitation of Al and N and strengthening of precipitation of Cu.

  However, the technology disclosed in Patent Literature 1 is a technology for diffusing and alloying a ferrite-forming element, orienting and growing a crystal, and the technology disclosed in Patent Literatures 2 and 3 is based on Nb, Zr, Ti, and V. This is a technique for performing precipitation of carbonitride, AlN, and Cu in finish annealing, and the technique disclosed in Patent Document 1 and the techniques disclosed in Patent Documents 2 and 3 are different from each other in a basic steel plate manufacturing technique. Therefore, the technology disclosed in Patent Documents 2 and 3 cannot be applied to the technology disclosed in Patent Document 1.

International Publication No. 2011/052654 JP-A-06-330255 JP 2010-024509 A

  An object of the present invention is to provide an Fe-based metal plate having excellent magnetic properties and strength in view of the above-mentioned state of the art.

  The Fe-based metal plate disclosed in Patent Literature 1 is not necessarily high in strength because the inside of the plate is composed of a single phase of α-Fe and easily formed of a coarse-grained structure oriented in {100} orientation. In order to achieve both magnetic properties and strength, the present inventors set the surface layer as a region of a coarse grain structure having a high degree of {200} plane integration as in Patent Document 1, and set the inner central layer to have a high strength. With the idea of using a three-layer Fe-based metal plate with an increased region, the growth of a layer of a coarse-grained structure with a high degree of {200} plane integration is suppressed, and the inside remains in the α-γ transformation region. Was considered.

  That is, using a base metal plate containing various elements which are considered to suppress the growth of crystal grains, an Fe-based metal plate was prepared according to the technique disclosed in Patent Document 1. As a result, by using a base metal plate containing a predetermined amount of a specific element such as Mn, a structure including a region of a coarse-grained structure having a high degree of {200} plane integration and a region of a fine-grained structure for increasing the strength is obtained. The inventors have found that an Fe-based metal plate can be obtained, and have found that the Fe-based metal plate has a high magnetic flux density and a high strength.

The present invention has been made based on the above findings, and the gist thereof is as follows.
(1) An Fe-based metal plate having a region where a ferrite-forming element is alloyed and concentrated,
The Fe-based metal is, by mass%, at least one of Si: 1.500% to 3.500% and Al: 0.500% to 3.000%, and Mn: 2.500% to 6%. .500% or less, and Ni: at least one of 2.500% to 6.500%.
At least a 0.2 μm region or the entire region from the surface of the region in which the ferrite-forming element is concentrated is an α-Fe single phase composition, and an inner region is a composition that can cause α-γ transformation,
The average grain size is defined as the average of the grain sizes in a plane parallel to the plate surface, the average grain size is more than 8 μm as a coarse grain structure, and the average grain size is 8 μm or less as a fine grain structure.
A region of at least 0.2 μm from the surface or the entire region of the region in which the ferrite forming element is concentrated is a region of a coarse grain structure,
{200} plane integration in the region of the coarse grain structure is 30% or more and 99% or less;
The region inside the region of the coarse grain structure is the fine grain structure, the thickness of Said sub grain structure by the thickness of the Fe-based metal plate is t, that is 1 / 10t or 7 / 10t or less Characterized Fe-based metal plate.
(2) The surface of the crystal grains occupying at least a 0.2 μm region or the entire region from the surface of the region in which the ferrite forming element is concentrated forms the surface of the plate, and further, the plate of the crystal particles The Fe-based metal plate according to the above (1), wherein a grain boundary inside is a boundary with the fine grain structure.
(3) The Fe system according to (1) or (2), wherein the X-ray random intensity ratio of {100} <011> in the region where the ferrite-forming element is concentrated is 50 or more and 400 or less. Metal plate.

  According to the present invention, an Fe-based metal plate having a high magnetic flux density and a high strength can be obtained.

1 shows a cross-sectional view in the thickness direction of an Fe-based metal plate.

  In the following description, “%” of the element content means “% by mass”. In addition, the crystal orientation and the crystal plane are generally described with respect to the steel sheet surface, which is used when expressing the crystal orientation in the steel sheet and the measured crystal plane and texture. That is, the crystal orientation is a direction perpendicular to the steel sheet surface, and the crystal plane is a plane parallel to the steel sheet surface. The expression is based on the body-centered cubic crystal structure, which is the α phase of Fe, and is based on the annihilation rule in X-ray measurement of the crystal plane. For example, {100} and {111} are used for the crystal orientation, and {200} and {222} are used for the crystal plane and texture, but these represent information about the same crystal grain. .

The Fe-based metal plate of the present invention has a region in which ferrite-forming elements are alloyed and concentrated, and a part or all of the region is a region of a coarse-grained structure, and the inside of the region is a region of a fine-grained structure. And a metal plate having a high magnetic flux density and a high strength such that the region where the ferrite forming element is concentrated has a high degree of {200} plane integration.
First, reasons for limiting individual conditions that define the present invention and preferable conditions for carrying out the present invention will be described.

  The Fe-based metal plate includes a surface layer in which the ferrite-forming element is concentrated and a central layer in which the ferrite-forming element is not concentrated. First, the definition of the boundary will be described.

  The concentrated portion where the ferrite-forming element specified in the present invention is concentrated is a region where the concentration of the ferrite-forming element is 1.1 times or more the concentration of the central part of the metal plate, and in the depth direction from the steel sheet surface, It has a thickness of 0.5 μm or more. If the thickness is less than 0.5 μm, the {100} oriented grains in the surface layer cannot be sufficiently developed, and it is difficult to increase the degree of {200} plane integration inside the steel sheet to 30% or more. The upper limit of the thickness of the concentrated portion is preferably 9 / 20t, where t is the thickness of the Fe-based metal plate. If the thickness exceeds 9/20 t, the thickness of the central layer cannot be made sufficiently large, and a metal plate having high strength cannot be obtained.

  A region where the concentration of the ferrite-forming element is less than 1.1 times the concentration of the central part of the steel sheet with respect to the concentrated portion of the ferrite-forming element is defined as a non-concentrated portion. In this specification, a concentrated portion of a ferrite-forming element may be described as “surface layer”, and a non-concentrated portion may be described as “center layer”. The boundary between the concentrated portion (surface layer) of the ferrite-forming element and the non-concentrated portion (center layer) of the ferrite-forming element can be determined, for example, by performing a line analysis on a cross section of the steel sheet in the thickness direction using EPMA. .

  As a method of forming the ferrite-forming element concentrated portion, there is a method of forming a film of the ferrite-forming element on the steel sheet surface and diffusing the ferrite-forming element in the direction of the center of the sheet thickness by heat treatment. In order to set the degree to 30% or more, it is not always necessary to alloy all of the coating, and it is possible to leave the coating on the surface within a range that does not significantly affect workability and the like. As described above, when a part of the film remains on the surface, the remaining film is not included in the concentrated portion of the ferrite forming element. Since Fe diffuses into the film from the base metal plate side in the heat treatment, it is determined that a region where the total content of elements other than Fe contained in the initial film is 50% or more remains. .

(Composition of Fe-based metal plate)
The Fe-based metal plate according to the present invention has at least one of Si: 1.500% or more and 3.500% or less and Al: 0.500% or more and 3.000% or less with respect to the entire Fe-based metal plate; It contains at least one of Mn: 2.500% to 6.500% and Ni: 2.500% to 6.500%, and further contains a ferrite-forming element.
The Si content is set to 1.500% or more and 3.500% or less. If it is less than 1.500%, a fine grain structure cannot be obtained. If it exceeds 3.500%, it becomes an α-single-phase component, and the texture cannot be adjusted to {100}. It is preferably from 2.000% to 3.500%.
The content of Al is set to 0.500% or more and 3.000% or less. If it is less than 0.500%, a fine-grained structure cannot be obtained. If it exceeds 3.000%, the magnetic flux density decreases. It is preferably from 0.500% to 2.500%.
The content of Mn is set to 2.500% or more and 6.500% or less. If it is less than 2.500%, a fine-grained structure cannot be obtained. If it exceeds 6.500%, the magnetic flux density decreases. It is preferably from 2.500% to 4.500%.
The content of Ni is set to 2.500% or more and 6.500% or less. If it is less than 2.500%, a fine-grained structure cannot be obtained. If it exceeds 6.500%, the magnetic flux density decreases. It is preferably from 2.500% to 6.500%.
When a plurality of types of γ-stabilizing elements are contained, the total content of the elements is preferably set to 2.500% or more and 6.000% or less.

(Composition of non-concentrated part / center layer of ferrite forming element)
The ratio of the non-concentrated portion / central layer of the ferrite forming element to the non-concentrated portion / central layer is Si: 1.500% to 3.500%, and Al: 0.500% to 3.000. % And at least one of Mn: 2.500% to 6.500% and Ni: 2.500% to 6.500%, and the total concentration of ferrite forming elements is It has a composition of the α-γ transformation component system which is less than 1.1 times the concentration of the central part and which is in the α phase at room temperature.
In the non-concentrated part / center layer of the ferrite-forming element, the concentration of Mn and Ni may increase near the boundary with the concentrated part / surface layer of the ferrite-forming element. The composition of the non-concentrated portion / central layer is the above composition in proportion to the entire non-concentrated portion / central layer.

(Concentration of ferrite-forming element / composition of surface layer)
The composition of the concentrated part / surface layer of the ferrite-forming element is such that the total concentration of the ferrite-forming element is 1.1 times or more the concentration of the center of the thickness of the metal plate in the composition of the non-concentrated part / center layer of the ferrite-forming element. The ferrite-forming element is added in such a manner.

(Concentrated part of ferrite forming element / thickness of surface layer)
It is preferable that the thickness of the concentrated portion / surface layer of the ferrite-forming element be 0.5 μm or more and 9/20 t or less. If the thickness is less than 0.5 μm, the {100} oriented grains in the surface layer cannot be sufficiently developed, and it is difficult to increase the degree of {200} plane integration inside the steel sheet to 30% or more. If the thickness exceeds 9/20 t, the thickness of the central layer cannot be sufficiently increased, and a metal plate having high strength cannot be obtained.

(Thickness of Fe-based metal plate)
The thickness of the Fe-based metal plate is preferably, for example, not less than 10 μm and not more than 5 mm. When the thickness is less than 10 μm, when the magnetic core is laminated and used as a magnetic core, the number of laminated layers increases, the gap increases, and it becomes difficult to obtain a high magnetic flux density. On the other hand, if the thickness is more than 5 mm, the {100} texture cannot be sufficiently grown, and it is difficult to obtain a high magnetic flux density.

(Structure of Fe-based metal plate)
FIG. 1 shows a cross-sectional view in the thickness direction of the Fe-based metal plate. At least a region of 0.2 μm from the surface or the entire region of the concentrated portion of the ferrite-forming element is an α-Fe single phase. The thickness of the α-single layer can be determined by performing a line analysis of the cross section of the Fe-based metal plate in the plate thickness direction using EPMA.

  In addition, at least the region of 0.2 μm from the surface or the entire region of the concentrated portion of the ferrite-forming element includes the α-Fe single phase region, and is the coarse grain structure 1. The coarse grain structure 1 is formed of a single crystal grain in the plate thickness direction (that is, the coarse grain layer is constituted by one crystal grain layer in the plate thickness direction) or a plurality of grains. It is formed by crystal grains (that is, a coarse grain layer is formed by two or more crystal grain layers in the thickness direction).

  When the region of the coarse grain structure 1 is composed of one layer of crystal grains, the surface of the crystal grains forms the surface of the plate, and the grain boundaries in the plate of the crystal grains are the same as the fine grain structure 2. Form the boundary. When the region of the coarse grain structure 1 is constituted by one crystal grain in the plate thickness direction, the degree of azimuthal integration of the {100} plane is increased, and thus there is an effect that the magnetic flux density is improved.

  The average grain size of the coarse grain structure 1 is larger than the average grain size of the fine grain structure, and is larger than 8 μm. The average crystal grain size is the average of the crystal grain sizes in a plane parallel to the plate surface. When the region of the coarse-grained structure 1 is composed of one layer of crystal grains, the crystal grain size in a field of 500 μm × 500 μm in at least one plane parallel to the plate surface in the region of the coarse-grained structure 1 The average crystal grain size is determined by measuring and averaging with an optical microscope. When the region of the coarse-grained structure 1 is composed of a plurality of crystal grains of two or more layers, in the region of the coarse-grained structure 1, the region is parallel to the plate surface and separated by 0.2 μm or more in the plate thickness direction. On a plurality of surfaces, the average crystal grain size is determined by measuring and averaging the crystal grain size in a visual field of 500 μm × 500 μm with an optical microscope.

  The grains of the coarse grain structure 1 are not limited to those having an average grain size of more than 8 μm in a plane parallel to the sheet surface and a grain size in the thickness direction of more than 8 μm, and are formed by rolling. Crystal grains having an average crystal grain size of more than 8 μm in a plane parallel to the plate surface to be formed and having a crystal grain size in the plate thickness direction of 8 μm or less, for example, flat crystal grains are also included.

  The thickness of the region that is the coarse-grained structure 1 can be determined by measuring using an optical microscope, and the region that is the coarse-grained structure 1 has a {200} plane integration of 30% or more and 99% or less. ｝ It is a texture. Even if Al and Si are contained in a steel sheet for the purpose of reducing iron loss due to an increase in electric resistance, it is difficult to sufficiently reduce iron loss by itself due to the effect of magnetostriction. When the content is in the above range, extremely good iron loss can be obtained.

  The Fe-based metal plate has a region composed of the fine-grained structure 2 inside the region of the coarse-grained structure 1. The fine grain structure 2 is a structure composed of crystals having an average crystal grain size of 8 μm or less. The average crystal grain size is the average of the crystal grain sizes in a plane parallel to the plate surface, similarly to the crystal grains having a coarse grain structure. In the region of the fine grain structure 2, on a plurality of surfaces parallel to the plate surface and spaced apart by 0.2 μm or more in the plate thickness direction, the crystal grain size in a visual field of 100 μm × 100 μm was measured with an optical microscope, and the average was measured. By doing so, the average crystal grain size is obtained.

  The region composed of the fine grain structure 2 has a thickness in the thickness direction of 1/10 t or more and 7/10 t or less, where t is the thickness of the Fe-based metal plate. If the thickness of the region composed of the fine-grained structure is less than 1/10 t, the effect of improving the strength cannot be obtained. On the other hand, if it exceeds 7/10 t, the ratio of the α-Fe single phase region of the coarse-grained structure having a {200} plane integration of 30% or more and 99% or less in the Fe-based metal plate is reduced, and the magnetic flux density is improved. Effect cannot be obtained. The thickness of the region composed of the fine grain structure is preferably 3/10 t or more and 5/10 t or less.

The thickness of the region composed of the fine-grained structure is such that the cross section of the surface of the Fe-based metal plate in the plate thickness direction is at least 20 points at 100 μm intervals in a direction parallel to the surface of the Fe-based metal plate. Is measured using an optical microscope, and the measured data is averaged. The average of the thickness is obtained by calculating the average value after excluding 10% of the measurement data from the minimum value side and the maximum value side of the measurement data. For example, the thickness is measured at 20 points every 100 μm, and the average is calculated from the measured data at 16 points, excluding two points from the minimum value of the thickness and two points from the maximum value of the thickness. Find the thickness.
In addition, when obtaining the thickness of the concentrated portion / surface layer of the ferrite forming element, the thickness of the α-monolayer, and the thickness of the coarse grain structure, the thickness of the region constituted by the fine grain structure is also determined. The measurement point is determined and the average value is calculated and obtained by the same method as the method for obtaining the value.

  The {200} plane integration of the {100} texture can be measured by X-ray diffraction using MoKα radiation. More specifically, for each sample, there are eleven orientation planes ({110}, {200}, {211}, {310}, {222}, {321}) with α-Fe crystals parallel to the sample surface. , {411}, {420}, {332}, {521}, {442}), and each measured value is divided by the theoretical integrated intensity of the sample in random orientation to obtain a total value. The ratio of the {200} intensity to is calculated as a percentage.

For example, the {200} intensity ratio is represented by the following equation (1).
{200} surface integration = [{i (200) / I (200)} / {i (hkl) / I (hkl)}] × 100
... (1)
However, the symbols are as follows.
i (hkl): Measured integrated intensity of {hkl} plane in sample measured I (hkl): Theoretical integrated intensity of {hkl} plane in sample having random orientation Σ: Sum of 11 orientation planes of α-Fe crystal Here, the integrated intensity of a sample having a random orientation may be obtained by preparing a sample and actually measuring it.

  Further, by setting the X-ray random intensity ratio of {100} <011> in the region where the ferrite forming element is concentrated to 50 or more and 400 or less, an effect of further improving the magnetic flux density can be obtained. The X-ray random intensity ratio is a ratio of the ratio of the measured X-ray diffraction intensity of {100} <011> of the sample to the X-ray diffraction intensity of {100} <011> in the sample having random orientation in the X-ray diffraction measurement. Value.

Next, a method for manufacturing the Fe-based metal plate of the present invention will be described. In the method described below, similarly to the manufacturing method described in Patent Document 1, a metal plate is subjected to a heat treatment of heating to a point A3 or higher and then cooling, and in the course of the heat treatment, a ferrite-forming element is diffused into the metal plate. Then, a technique of forming a region of the α-Fe single phase component system in which the ferrite forming element is concentrated and increasing the degree of {200} plane integration after the heat treatment is used.
At this time, the ferrite forming element is diffused into the metal plate to form a region of a coarse-grained structure having a higher degree of {200} plane integration in the surface layer after the heat treatment, and the ferrite forming element in the central layer is not concentrated. In the region of the γ transformation component system, a fine grain structure is formed by utilizing the γ-α transformation during heat treatment.
Hereinafter, preparation of the base metal plate and heat treatment of the base metal plate will be described in this order.

[Preparation of base metal plate]
As the base metal plate, a base metal plate having the component composition of the above-described Fe-based metal plate and having strain introduced into the surface layer is used. This is because, when the base metal plate is recrystallized, a large number of crystal grains whose plane parallel to the rolling plane is oriented in {100} are generated, and the degree of {200} plane integration of the α-Fe single phase is improved. For example, it is preferable to introduce a processing strain having a dislocation density of 1 × 10 ¹⁵ m / m ³ or more and 1 × 10 ¹⁷ m / m ³ or less. The method of causing such strain is not particularly limited. For example, it is preferable to perform cold rolling at a high rolling reduction, particularly at a rolling reduction of 97% or more and 99.99% or less. Further, a shear strain of 0.2 or more may be generated by cold rolling. The shear strain can be generated, for example, by rotating upper and lower rolling rolls at different speeds during cold rolling. In this case, the greater the difference between the rotational speeds of the upper and lower rolling rolls, the greater the shear strain. The magnitude of the shear strain can be calculated from the difference between the diameter of the rolling roll and the rotation speed.

[Adhesion of ferrite forming element]
(Type of ferrite forming element)
A ferrite-forming element other than Fe is diffused into the base metal sheet in which the strain is accumulated, and the region oriented {100} in the thickness direction of the steel sheet is increased.
For this purpose, a ferrite-forming element is deposited as a second layer on both sides of a base metal plate made of an α-γ transformation type Fe-based metal in a layered manner, and a region where the element is diffused and alloyed is formed as an α-Fe single phase. A bud of {100} orientation to increase the degree of {200} plane integration.
As such a ferrite-forming element, at least one of Al, Cr, Ga, Ge, Mo, Sb, Si, Sn, Ti, V, W, and Zn can be used alone or in combination.

(How to attach ferrite-forming elements)
Various methods such as plating methods such as hot dip plating and electrolytic plating, rolling clad methods, dry processes such as PVD and CVD, and powder coating methods can be used to attach the ferrite-forming element in a layered manner to the surface of the base metal plate. Can be adopted. A plating method or a rolled clad method is suitable as an efficient method for depositing a ferrite-forming element for industrial implementation.
The adhesion thickness of the ferrite-forming element before heating is desirably 0.05 μm or more and 1000 μm or less. If the thickness is less than 0.05 μm, sufficient {200} plane integration cannot be obtained. On the other hand, when the thickness exceeds 1000 μm, the thickness of the ferrite-forming element adhered to the surface becomes unnecessarily large even when it remains on the surface.

[Heat diffusion treatment]
A base metal plate to which, for example, Al is attached as a ferrite forming element is heated to the point A3 of the base material to recrystallize, and Al is diffused into a part of the base metal plate to be alloyed with the base material. .
When high working strain is imparted when the base metal plate is recrystallized, a texture oriented to {100} is formed after the recrystallization. Further, as the temperature rises, Al diffuses into the metal plate and is alloyed with iron, but becomes an α-Fe single phase component in the alloyed region, and transforms from γ phase to α phase in that region. At this time, since the transformation takes over the orientation of the {100} texture formed in the surface layer, a texture oriented to {100} is formed even in the alloyed region.
As a result, in the alloyed region, the degree of {200} plane integration of the α-Fe single phase was 25% or more and 50% or less, and accordingly, the degree of {222} plane integration was 1% or more and 40% or less. An organization is formed.

The base metal plate is further heated and maintained at a temperature of 1300 ° C. or lower.
The {100} crystal grains are preserved as they are in the already alloyed region without the γ transformation, and the {100} crystal grains are preserved as they are. Increase.
However, if the holding temperature is high or the holding time is too long, the transformation from the γ phase to the α phase tends to proceed, and the fine grain structure is not formed inside the coarse grain structure, so the base metal sheet The retention temperature (the temperature including the point less than the A3 point) and the retention time are adjusted according to the component composition of (1) to stop diffusion of Al, orientation to {100} grains, and grain growth of {100} grains.

The holding temperature after the temperature rise is preferably 1300 ° C. or less. The effect on magnetic properties saturates even when heated at a temperature exceeding 1300 ° C. As for the heating and holding time, cooling may be started immediately after reaching the holding temperature (in that case, substantially held for 0.01 second or more), or cooled for 600 minutes or less. You may start. The effect saturates even if it is maintained for more than 600 minutes.
When this condition is satisfied, the integration of the {200} plane oriented buds is further promoted, and the degree of {200} plane integration of the α-Fe single phase after cooling can be more than 30%.

  Further, the present invention is to make the inside of the coarse-grained structure a fine-grained structure and does not improve the {200} plane integration degree of the α-Fe single phase over the entire plate. If the {200} plane integration degree of the Al alloyed region becomes 30% or more and 99% or less by heating to the A3 point of the material, the base metal plate may be heated and held at less than the A3 point. Alternatively, the step of heating and holding the base metal plate at a temperature of 1300 ° C. or lower may be omitted.

[Cooling after heat diffusion treatment]
After the diffusion treatment, when cooling is performed in a state where the region where Al has not been alloyed remains, the region where the alloy is not alloyed contains an element such as Mn which slows down the movement speed of the grain boundary at the time of phase transformation. Transformation from the phase to the α phase becomes difficult to progress, and usually, at the time of the transformation from the γ phase to the α phase during cooling, the crystal oriented in {100} grows greatly, but the crystal growth stops, Alternatively, the progress of crystal growth is slowed, and the internal region that is not alloyed has a fine grain structure. In addition, at the time of cooling after the diffusion treatment, the cooling rate is not particularly limited, but is preferably from 0.1 ° C./sec to 500 ° C./sec.

  Whether the coarse-grained structure is composed of one layer of crystal grains or two or more layers of crystal grains depends on the thickness of the base metal plate, the holding time during heat treatment of the base metal plate, It changes depending on the holding temperature. In order to form the coarse grain structure with one layer of crystal grains, the structure is held at a higher temperature for a long time, and the cooling to at least the A3 point or less in the cooling process is gradually cooled.

  As a result, an Fe-based metal plate having a coarse-grained structure having a region with a {200} plane integration degree of 30% or more and 99% or less and an α-Fe single phase region and a fine-grained structure region is obtained.

  Next, an example of the present invention will be described. The conditions in the example are one condition example adopted for confirming the operability and the effect of the present invention. It is not limited. The present invention can employ various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

(Example 1)
The effect of the component composition of the base metal plate was studied. An ingot was cast by melting to have a component composition shown in Table 1 (the remainder is Fe and inevitable impurities). The ingot was hot-rolled in the γ region to a thickness of 50 mm, and subsequently worked warm or cold to obtain a base metal plate. As a comparative example, a base metal plate containing Mn, Ni, Si, and Al with a content outside the range of the present invention was prepared.

Next, the coating elements (ferrite-forming elements) shown in Table 2 were adhered to both surfaces of the base metal plate. The film element was attached by an ion plating method or a plating method. The thickness of the coating element (the total thickness on both sides) shown in Table 2 is a value obtained by summing the thicknesses measured on each side. Next, at the holding temperature and holding time shown in Table 2, the base metal plate to which the coating element was adhered was heat-treated. An infrared furnace was used as the heat treatment furnace, and heat treatment was performed in an atmosphere evacuated to a level of 10 ⁻³ Pa.

Table 3 shows the evaluation results of the structure of the obtained Fe-based metal plate, the thickness of the α-monolayer, the layer structure of coarse grains, the thickness of the fine grain structure, the magnetic properties, and the strength.
Regarding the structure, the {200} plane integration degree and the X-ray random intensity ratio of {100} <011> were determined by the X-ray diffraction method.
The measurement of the thickness of the α-single layer was obtained by performing a line analysis of a cross section of the metal plate in the plate thickness direction using EPMA. The α-monolayer is formed in two layers on both sides of the fine grain structure in the plate thickness direction, but since the thicknesses of these two layers are equal, only the thickness of one α-monolayer is measured. did. The layer structure of the coarse grains and the thickness of the fine grain structure inside the metal plate were measured and determined using an optical microscope.

Regarding magnetic properties, a sample was cut out from a direction at 45 ° to the rolling direction, and a magnetic flux density B50 and a saturation magnetic flux density Bs for a magnetization force of 5000 A / m were measured. In the measurement of the magnetic flux density B50, the measurement frequency was set to 50 Hz using SST (Single Sheet Tester). In the measurement of the saturation magnetic flux density Bs, a magnetizing force of 0.8 × 10 ⁶ A / m was applied using a VSM (Vibrating Sample Magnetometer). Then, the ratio B50 / Bs of the magnetic flux density B50 to the saturation magnetic flux density Bs was calculated.
Regarding the strength of the Fe-based metal plate, a No. 5 tensile test piece described in JIS Z2201 was sampled in a direction perpendicular to the rolling direction, and a tensile test was performed according to the test method described in JIS Z2241 to evaluate the tensile strength.

As shown in Table 3, each of Invention Examples 1 to 5 and 7 to 20 has an α-Fe single phase having a coarse-grained structure, and the thickness of the α-Fe single phase is 0.2 μm or more, The {200} plane integration of the -Fe single phase was 30% or more. The region inside the coarse grain structure was a fine grain structure composed of fine grains having an average crystal grain size of 8 μm or less. The thickness of the fine grain structure was 1/10 t or more and 7/10 t or less. In Comparative Examples 1, 3, 5 to 8, no region of fine grain structure was observed. Therefore, the tensile strengths of Comparative Examples 1, 3, 5 to 8 were lower than those of Inventive Examples 1 to 5, 7 to 20. In addition, the magnetic properties of Inventive Examples 1 to 20 were higher than Comparative Examples 1, 3, and 5 to 8, and both magnetic properties and strength were compatible.
In Comparative Examples 2 and 4, since they were α-single-phase components, no coarse-grained structure was formed even when the ferrite-forming element was attached and diffused.

(Example 2)
The effects of the coating elements (ferrite-forming element and austenite-forming element), the holding temperature and holding time of the heat treatment of the base metal plate, and the thickness of the fine grain structure were examined.
The coating elements shown in Table 4 were attached to both surfaces of the base metal plate. The film element was attached by an ion plating method or a plating method. The thickness of the coating element (the total thickness on both sides) shown in Table 4 is a value obtained by summing the thicknesses measured on each side. Next, at the holding temperature and holding time shown in Table 4, the base metal plate to which the coating element was adhered was heat-treated. An infrared furnace was used as the heat treatment furnace, and heat treatment was performed in an atmosphere evacuated to a level of 10 ⁻³ Pa. Table 5 shows the evaluation results of the structure of the obtained Fe-based metal plate, the thickness of the α-monolayer, the layer structure of coarse grains, the thickness of the fine grain structure, the magnetic properties, and the tensile strength. In addition, in the same manner as in Example 1, in the measurement of the thickness of the α-monolayer, only the thickness of one of the two α-monolayers formed on both sides of the fine grain structure in the thickness direction was measured. did.

  Inventive Examples 21 to 40 all have a region of coarse grain structure, and as shown in Table 5, the thickness of the α-Fe single phase is 0.2 μm or more, and the {200} plane integration degree is 30% or more. Met. In Invention Examples 21 to 40, the region inside the coarse-grained structure was a fine-grained structure composed of fine particles having an average crystal grain size of 8 μm or less. The thickness of the fine grain structure was 1/10 t or more and 7/10 t or less.

  Comparative Examples 9 and 15 are the case where the austenite forming element was adhered to the surface or the case where the ferrite forming element was not adhered, and the texture could not be controlled and the high magnetic flux density could not be obtained. Was. In Comparative Examples 10 and 11, the thickness of the ferrite forming element is not appropriate, and in Comparative Examples 12 to 14, the holding temperature and the holding time of the heat treatment of the base metal plate are not appropriate, and the magnetic properties or tensile strength are insufficient. Did not improve.

  According to the present invention, an Fe-based metal plate having a high magnetic flux density and a high strength can be obtained. Therefore, the present invention has high industrial applicability.

1 Coarse grain structure 2 Fine grain structure

Claims (3)

A Fe-based metal plate having a region where a ferrite-forming element is alloyed and concentrated,
The Fe-based metal is, by mass%, at least one of Si: 1.500% to 3.500% and Al: 0.500% to 3.000%, and Mn: 2.500% to 6%. .500% or less, and Ni: at least one of 2.500% to 6.500%.
At least a 0.2 μm region or the entire region from the surface of the region in which the ferrite-forming element is concentrated is an α-Fe single phase composition, and an inner region is a composition that can cause α-γ transformation,
The average grain size is defined as the average of the grain sizes in a plane parallel to the plate surface, the average grain size is more than 8 μm as a coarse grain structure, and the average grain size is 8 μm or less as a fine grain structure.
A region of at least 0.2 μm from the surface or the entire region of the region in which the ferrite forming element is concentrated is a region of a coarse grain structure,
{200} plane integration in the region of the coarse grain structure is 30% or more and 99% or less;
The region inside the region of the coarse grain structure is the fine grain structure, the thickness of Said sub grain structure by the thickness of the Fe-based metal plate is t, that is 1 / 10t or 7 / 10t or less Characterized Fe-based metal plate.   The surface of the crystal grains occupying at least a 0.2 μm region or the entire region from the surface of the region in which the ferrite-forming element is concentrated forms the surface of the plate, and further, the crystal particles in the plate The Fe-based metal plate according to claim 1, wherein a boundary is a boundary with the fine grain structure.   3. The Fe-based metal plate according to claim 1, wherein an X-ray random intensity ratio of {100} <011> in a region where the ferrite-forming element is concentrated is 50 or more and 400 or less. 4.

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