JP2016183360A - Fe-BASED METAL PLATE - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Fe-based metal plate excellent in magnetic properties and iron loss.SOLUTION: In an Fe-based metal plate, Fe-based metal contains 1.5-3.5% Si and 0.5-3.0% Al, and contains 2.5-6.5% Mn and 2.5-6.5% Ni as austenite-forming elements, the concentration of the austenite-forming elements in a layer A is 1.1 times or more that of a plate thickness center, the concentration of the austenite-forming elements in a layer B is 1.1 times or more that of the average of the total plate thickness, the layer A is present on the outer side of the layer B, the electrical resistivity of the layer B is 1.1 times or more that of the layer A, the thickness of the layer A is 0.5 μm or more, an area at a depth of at least 0.2 μm from the surface of the layer A or the whole area of the layer A has a composition forming an α-Fe single phase and the inside of the layer A is an area having a composition causing α-γ transformation, the area at a depth of at least 0.2 μm from the surface of the layer A or the whole area of the layer A has an average crystal grain size of 8 μm or more and the integration degree of a {200} plane of the area having the average crystal grain size is 30% or more, a part of the layer B has an average crystal grain size of less than 8 μm and when the plate thickness is defined as t, the thickness of the area having the average crystal grain size is more than 0 and less than (1/20)t.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an Fe-based metal plate that is suitable for magnetic cores used for electromagnetic parts such as electric motors, generators, transformers, and the like and that has reduced iron loss that can contribute to downsizing and energy loss reduction 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 a silicon steel sheet are a high magnetic flux density in a practical magnetic field and a low magnetic energy loss (iron loss) in an alternating magnetic field.

  Regarding the technology for increasing the magnetic flux density of the steel sheet, when the {100} plane of the α-Fe phase is highly integrated in the rolled surface, the <100> axis is accumulated in the rolled surface, and the same magnetic field was applied. In this case, since a higher magnetic flux density can be obtained, various methods for highly integrating {100} planes parallel to the plate surface of the silicon steel plate have been proposed.

In the patent document 1, the present inventors have also proposed a technique for making the following steel plate a high magnetic flux density. In Patent Document 1, (a) a ferrite-forming element is attached to one side or both sides of a base metal plate made of an α-γ transformation-based Fe-based metal, and (b) the base metal plate is moved from room temperature to the base material. The metal plate is heated to point A ₃ to diffuse the ferrite-forming elements in the base metal plate, and a part thereof is alloyed with the base material, and the {200} face of the α-Fe phase in the alloyed region the degree of integration was 50% or less than 25%, and not more than 40% {222} plane integration, (c) heating the base metal plate to a temperature higher than ₃ points a, hold, and ferrite forming elements Regarding the surface integration degree of the alloyed α-Fe phase, the {200} plane integration degree is increased and the {222} plane integration degree is decreased, and (d) the base metal plate is cooled to a temperature lower than the A3 point. When the γ-Fe phase in the non-alloyed region is transformed into the α-Fe phase, the α-Fe phase 200} plane integration to increase the {200} plane integration becomes 99% or less than 30%, and technology that {222} plane integration becomes 30% or less is disclosed.

  On the other hand, regarding the technology for reducing the iron loss of the steel sheet, a method of reducing iron loss by adding a high specific resistance element such as Si to the steel sheet to increase the electric resistance of the steel sheet, impurities or inclusions in the steel sheet The method of reducing iron loss by reducing the thickness, the method of reducing iron loss by reducing the plate thickness of the steel sheet, artificially introducing grooves and strain on the surface of the steel sheet, and subdividing the magnetic domains Therefore, a method for reducing the iron loss is generally known.

  In the patent document 2, the present inventors have also proposed a technique for making the following steel sheet low in iron loss. In Patent Document 2, the X-ray random intensity ratios of {001} <470>, {116} <6 12 1>, {223} <692> on the surface of the Fe-based metal plate are A, B, and C, respectively. When Z = (A + 0.98B) / (4 × 0.98C), 0.5 <Z ≦ 50, stress is applied to the crystal lattice of the α-Fe phase, and the magnetic domain width is narrowed. Thus, a technique for reducing iron loss by suppressing eddy current is disclosed.

  The technique disclosed in Patent Document 2 is an effective technique for obtaining a steel sheet having a high magnetic flux density and a low iron loss. However, in recent years, from the viewpoint of energy saving, there has been a strong demand for improving the efficiency of electrical equipment, and it has been desired to further reduce iron loss in magnetic core materials.

Japanese Patent No. 5136687 JP 2014-150247 A

  An object of the present invention is to provide an Fe-based metal plate excellent in magnetic characteristics and iron loss in view of the above-described current state of the prior art.

  The technique disclosed in Patent Document 2 is such that the electrical resistivity of the central portion of the plate thickness is 38 μΩ · cm or more and 200 μΩ · cm or less, and the electrical resistivity of the outermost layer is made higher than the electrical resistivity of the central portion of the plate thickness. The crystal orientation of the Fe-based metal plate is controlled to narrow the magnetic domain width. The present inventors further studied a means for achieving a reduction in iron loss of the Fe-based metal plate while referring to the technique disclosed in Patent Document 2. As a result, contrary to the technique disclosed in Patent Document 2, the inventors have conceived that the electrical resistivity at the central portion of the plate thickness is made higher than the electrical resistivity of the outermost layer.

  That is, in the Fe-based metal plate, by making the electrical resistivity at the central portion of the plate thickness higher than the electrical resistivity of the outermost layer, the highly integrated region on the {100} planes on both plate surface sides Are arranged with a region of high electrical resistivity therebetween and are electrically separated. The structure of the highly integrated area on the {100} planes on both plate surfaces and the area of high electrical resistivity at the center of the plate thickness are similar to the iron core laminated with thin electromagnetic steel plates whose surfaces are insulated. The thickness of one region highly integrated on the {100} plane is reduced, and it is considered that the same effect as reducing the thickness of the steel sheet, that is, the effect of reducing iron loss can be obtained.

  Therefore, the present inventors have examined means for realizing it. As a result, the surface side of the steel sheet is made a highly integrated region of {100} by diffusion of the ferrite-generating element, and the central portion of the plate thickness is concentrated with the diffusion of the ferrite-generating element, and the austenite-generating element in the base material is concentrated, and { It was found that a region having a higher electrical resistivity than the region highly integrated at 100} is formed, and the iron loss of the Fe-based metal plate can be reduced.

The present invention has been made based on the above findings, and the gist thereof is as follows.
(1) Fe-based metal is an average mass% of the entire metal plate, Si: 1.500% or more and 3.500% or less, and Al: 0.500% or more and 3.000% or less, As an austenite generating element, Mn: 2.500% or more and 6.500% or less, and Ni: 2.500% or more and 6.500% or less are included,
Layer A: a region where the concentration of the ferrite-forming element is 1.1 times or more the concentration at the center of the thickness of the metal plate,
B layer: As a region where the concentration of the austenite-generating element is 1.1 times or more of the average thickness of the entire metal plate,
A layer exists on the surface layer side from the B layer at least on one side from the thickness center in the thickness direction of the metal plate,
The electrical resistivity of the B layer is 1.1 times or more of the electrical resistivity of the A layer,
The thickness of the A layer is 0.5 μm or more;
A region of 0.2 μm or all region from the surface of the A layer has a composition of α-Fe single phase, and a region having a composition capable of causing α-γ transformation exists inside thereof.
An average crystal grain size of at least 0.2 μm from the surface of the layer A or the entire region is 8 μm or more,
{200} plane integration degree is 30% or more in the region where the average crystal grain size in the A layer is 8 μm or more,
The average crystal grain size of a part of the B layer is less than 8 μm,
The Fe-based metal plate, wherein the thickness of the region having an average crystal grain size of less than 8 μm in the B layer is more than 0 and less than 1/20 t, where t is the thickness of the metal plate.
(2) In the region where the average crystal grain size in the A layer is 8 μm or more, the surface of the crystal grain forms the surface of the plate, and the grain boundary in the plate of the crystal grain is one of the B layer. The Fe-based metal plate according to (1) above, wherein an average crystal grain size of a part region is a boundary with a region of less than 8 μm.

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

Sectional drawing of the thickness direction of a Fe-type metal plate is shown.

  In the following description, “%” of the element content means “mass%”. The crystal orientation and the crystal plane are generally described with respect to the steel plate surface used for expressing the crystal orientation in the steel plate and the crystal plane and texture to be measured. That is, the crystal orientation is an orientation perpendicular to the steel plate surface, and the crystal plane is a plane parallel to the steel plate surface. In addition, the expression is based on the extinction law in the X-ray measurement of the crystal plane caused by the body-centered cubic crystal structure which is the α phase of Fe. For example, {100} and {111} are used for crystal orientation, and {200} and {222} are used for crystal planes and textures, which represent information about the same crystal grains. .

The Fe-based metal plate of the present invention has a region in which a ferrite-forming element is alloyed and concentrated on the surface layer of the metal plate, and a part or all of the region is a coarse grain region having a high {200} plane integration degree Thus, the austenite generating element is concentrated inside the region, and a fine grain region having a higher electric resistivity than the region where the ferrite forming element of the surface layer is concentrated is provided. By having such a configuration, the Fe-based metal plate of the present invention is a metal plate having a high magnetic flux density and a low iron loss.
Reasons for limiting the individual conditions defining the present invention and preferable conditions for carrying out the present invention will be described.

  The Fe-based metal plate has a clear concentration gradient of contained elements in the plate thickness direction. First, the composition of the metal plate and the concentration distribution in the plate thickness direction will be described.

(Composition of Fe metal plate)
The Fe-based metal plate of the present invention is an average mass% of the entire Fe-based metal plate, at least Si: 1.500% to 3.500%, and Al: 0.500% to 3.000%. On the other hand, it contains at least one of Mn: 2.500% or more and 6.500% or less and Ni: 2.500% or more and 6.500% or less as an austenite forming element, and further contains a ferrite forming element To do.
When the Si content is less than 1.500%, a region having a high electrical resistivity cannot be obtained. 3. If it exceeds 500%, it becomes an α single phase component, and the texture cannot be aligned to {100}. It is preferably 2.000% or more and 3.500% or less.
When the Al content is less than 0.500%, a region having a high electrical resistivity cannot be obtained. If it exceeds 3,000%, it becomes an α single-phase component, and the texture cannot be aligned to {100} even if the ferrite-forming element is diffused. 0.500% or more and 2.500% or less are preferable.
If the Mn content is less than 2.500%, a region having a high electrical resistivity cannot be obtained. If it exceeds 6.500%, the magnetic flux density decreases. 2.500% or more and 4.500% or less are preferable.
When the Ni content is less than 2.500%, a region having a high electrical resistivity cannot be obtained. If it exceeds 6.500%, the magnetic flux density decreases. It is preferably 2.500% or more and 6.500% or less.
Note that when a plurality of types of austenite-generating elements are contained, the total content of the elements is preferably 2.500% or more and 6.000% or less.

(Element distribution of layer A and layer B and configuration in the plate thickness direction)
FIG. 1 shows a cross-sectional view in the thickness direction of the Fe-based metal plate.
The present invention defines various regions in the thickness direction. In particular, when the positional relationship from the plate surface is specified, the effect of the invention can be obtained if the metal plate satisfies the requirements on either the one surface side, the front surface side or the back surface side from the plate thickness center. Is possible. In the following description, an area on an arbitrary surface side from the thickness center is described.

  For example, when the region that is the B layer extends to both surface sides across the plate thickness center, the B layer is not an entire B layer, but an explanation of a region on any one side surface from the plate thickness center. If the region extends with a symmetric thickness from the center of the plate thickness, the description will be made with a region having a thickness of ½ of the thickness of the B layer itself. For example, “the thickness of the B layer” is “a thickness from the center of the plate thickness toward any one side”.

  Needless to say, it is preferable to satisfy both sides from the center of the plate thickness. Further, unless there is a particular reason and a special manufacturing method is not adopted, the metal plate generally has a material change symmetrical to the center of the plate thickness, and the values defined in the present invention are substantially the same values on both surface sides. In particular, in the manufacturing method described later, a substantially symmetric metal plate can be obtained with respect to the thickness center. Needless to say, the characteristic values of the metal plate such as magnetic properties are values measured for the entire plate.

In the metal plate of the present invention, the element having the above average content is distributed with a clear concentration gradient in the plate thickness direction. This distribution is controlled separately for ferrite-forming elements and austenite-forming elements.
The metal plate of this invention has the area | region where the density | concentration of a ferrite production | generation element is 1.1 times or more of the density | concentration of the plate | board thickness center of a metal plate. This region is referred to as the A layer in the present invention. The A layer is an area located on the surface layer side when the metal plate is viewed in the thickness direction. Preferably it is 1.5 times or more, More preferably, it is 2.0 times or more.

  In addition, the metal plate of the present invention has a region where the concentration of the austenite-generating element is 1.1 times or more of the average thickness of the metal plate. This region is referred to as B layer in the present invention. The B layer is an area located on the center layer side when the metal plate is viewed in the thickness direction. Preferably it is 1.5 times or more, More preferably, it is 2.0 times or more.

It should be noted here that the A layer and the B layer are independent definitions, and the metal plate may include regions that are both the A layer and the B layer. Conversely, there may be a region that is neither the A layer nor the B layer.
In the present invention, in the configuration in the thickness direction of the metal plate, the A layer needs to exist on the surface layer side from the B layer. Here, being present on the surface layer side means existing on both sides of the metal plate.

Furthermore, the metal plate of this invention makes the electrical resistivity of B layer 1.1 times or more of the electrical resistivity of A layer. Preferably it is 1.5 times or more, More preferably, it is 2.0 times or more.
The reason for this is that the metal plate of the present invention forms a layer with high electrical resistivity in the central region of the plate and functions that layer as an insulating layer, thereby reducing the thickness of the metal plate and reducing the iron loss. This is because it aims to lower the value. If the ratio is less than 1.1, the B layer does not function as an insulating layer, and the effects of the invention cannot be obtained sufficiently.

The electrical resistivity is obtained by the following formula (1). This equation (1) is an equation obtained by experiments. Here, for each element concentration, an average value for each layer is used.
ρ (μΩ · cm) = 9.9 + 12.4 [Si%] + 6 [Al%]
+2.5 [Mn + Ni%] (1)

  One method for forming the A layer is to form a ferrite-forming element film on the plate surface and diffuse the ferrite-generating element toward the center of the plate thickness by heat treatment, but it is not always necessary to alloy all of the films In order to obtain corrosion resistance and some coating effect, it is also possible to leave the film on the surface within a range that does not significantly affect the magnetic properties. As described above, when a part of the film remains on the surface, the remaining film is not included in the A layer and is not considered in the specification of the present invention. Since Fe diffuses from the base metal plate side in the coating in the heat treatment, the region where the total content of elements other than Fe contained in the initial coating is 50% or more is judged as a remaining coating. .

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

  The A layer has a thickness of 0.5 μm or more in the depth direction from the plate surface. If this thickness is less than 0.5 μm, it will be difficult to sufficiently develop {100} oriented grains described later. The upper limit of the thickness of the A layer is preferably 9/20 t, where t is the thickness of the Fe-based metal plate. The metal plate of the present invention exhibits an effect by concentrating the austenite-generating element in a region where the ferrite-forming element is not concentrated. When the thickness of the A layer exceeds 9/20 t, B A sufficient thickness of the layer cannot be obtained, and a metal plate having a low iron loss cannot be obtained.

(Element distribution and transformation behavior)
In the metal plate of the present invention, in addition to the distribution related to the concentration at the center of the thickness of the ferrite-forming element and the austenite-forming element, the element distribution in each region needs to be related to the transformation behavior. This is because, as will be described later, in the metal plate of the present invention, crystal orientation control is performed in relation to the transformation behavior.

  In the metal plate of the present invention, at least a 0.2 μm region or all regions from the surface of the A layer have an α-Fe single phase composition, and a composition capable of causing an α-γ transformation on the center layer side. The area must exist. Here, the region having a composition capable of causing the α-γ transformation does not need to be in the A layer, and may be a region that extends to the B layer or other layers. Of course, it may be a region that is not the A layer, exists in the B layer or other layers.

  In the present invention, based on the amount of elements contained in the region, the composition of the α-Fe single phase is determined by the equation (2), and the composition that can cause the α-γ transformation is determined by the equation (3). If this configuration is not satisfied, the {100} texture described later cannot be sufficiently grown, and it is difficult to obtain a high magnetic flux density.

45 × [Si%] + 88 × [Al%] − 20 × [Mn%] − 18 × [Ni%] − 75 ≧ 0
... (2)
45 × [Si%] + 88 × [Al%] − 20 × [Mn%] − 18 × [Ni%] − 75 <0
... (3)

  The element distribution for determining the A layer, the B layer, and the above transformation behavior can be determined, for example, by performing line analysis or mapping of the cross section in the plate thickness direction of the metal plate using EPMA. In order to avoid variation due to the measurement location, measurement may be performed at 10 or more locations, and the average may be determined.

(Metal plate structure)
The metal plate of the present invention is also characterized by a change in crystal grain size in the plate thickness direction.
The metal plate of the present invention has an average crystal grain size of 8 μm or more in at least a 0.2 μm region or all regions from the surface of the region of the α-Fe single phase composition in the A layer.

When the thickness of the region having the average crystal grain size of 8 μm or more is 0.2 μm or less, the effect of improving the magnetic characteristics by increasing the {200} plane integration degree described later cannot be obtained. Further, if this thickness is larger than the region of the α-Fe single phase composition in the A layer, it becomes difficult to secure a region functioning as an insulating layer described later, and the effects of the invention cannot be obtained. .
Here, the region where the average crystal grain size is 8 μm or more does not need to remain in the region of the α-Fe single phase composition in the A layer or in the A layer, but the B layer or other layers, etc. It doesn't matter if it extends to

  In the metal plate of the present invention, a part or all of the region in the B layer has an average crystal grain size of less than 8 μm. The thickness of this region is more than 0 and less than 1/20 t, where t is the thickness of the Fe-based metal plate. In the present invention, this region functions as an insulating layer, and is for reducing the iron loss by reducing the substantial thickness of the metal plate. Without this region, the iron loss is not reduced.

  In addition, since the magnetic flux density is not expected to contribute to the characteristics, it is preferably as thin as possible, and the upper limit is set to 1/20 t. Further, when this region becomes thicker, the proportion of the region where the average crystal grain size where the {200} plane integration degree preferable for improving the magnetic flux density described later is to be formed is less than 8 μm, and the effect of improving the magnetic flux density cannot be obtained. Preferably they are 1 / 50t or more and 2 / 25t or less. In addition, the area | region where the said average crystal grain diameter is less than 8 micrometers here does not need to stay in B layer, and may extend to A layer or other layers.

  When the crystal grains in the region where the average crystal grain size is 8 μm or more are very large, the surface of the crystal grains forms the surface of the metal plate, and at the same time, the grain boundary on the opposite side of the crystal grains is the average crystal grain A boundary with a region having a diameter of less than 8 μm is formed. That is, the metal plate is also formed in the plate thickness direction with a single crystal grain present on the center side from the surface and fine crystal grains present in the central region.

  Thus, when the surface layer region is constituted by one crystal grain, the orientation integration degree of the {100} plane of the surface layer portion to be described later is increased, which is preferable for the present invention because the magnetic flux density is improved. Moreover, it is preferable from the viewpoint of improving the magnetic flux density that the region where the average crystal grain size is 8 μm or more is composed of a small number of crystal grains in the thickness direction, even if not one layer.

What should be noted here is the method for measuring the average grain size.
The average crystal grain size in the present invention does not need to consider the grain size in the plate thickness direction. This is because, for example, when the metal plate itself is thin, the thickness of the A layer itself is particularly thin due to the manufacturing method or element distribution design, or the growth direction of the crystal grains is biased depending on the manufacturing method, This is because the object of the present invention can be achieved as long as the crystal grain size is small even if the crystal grain size in the cross section parallel to the surface of the metal plate can be increased. In order to define the crystal grain size required in the present invention even in such a situation, in the present invention, the average crystal grain size is determined by the cutting method only in the direction parallel to the plate surface in the plate thickness section observation. By performing this measurement a plurality of positions in the plate thickness direction, it is possible to grasp the change in the average crystal grain size in the plate thickness direction. The average crystal grain size is 8 μm or more, and the average crystal grain size is 8 μm. Less than the region thickness can be determined simultaneously.

In order to increase the magnetic flux density, the metal plate of the present invention is characterized by increasing the {200} plane integration degree in the region in the plate thickness direction.
In the present invention, the {200} plane integration degree is 30% or more and 99% or less in the region where the average crystal grain size in the A layer is 8 μm or more.

  The reason why the region that increases the {200} plane integration degree is limited to the A layer is that this region has a composition that easily forms an α phase, is easy to control texture, has high saturation magnetic flux density, and is optimal for high magnetic flux density. Because there is. Further, the reason why the average crystal grain size is limited to a region having an average crystal grain size of 8 μm or more is that the magnetic flux density can be improved by increasing the degree of integration of crystal orientation by grain growth. Needless to say, there is no problem even if the crystal region having the {200} plane extends beyond this region, and the effect of the present invention regarding the magnetic flux density can be obtained satisfactorily.

  Moreover, a good magnetic flux density cannot be obtained unless the surface integration degree is 30% or more. The upper limit is not particularly limited and may be 100%. For example, in a practical grain-oriented electrical steel sheet, the degree of integration with respect to the Goss orientation is substantially 100%, and the degree of integration is not a plane orientation, but is evaluated by a slight misalignment within several degrees near the Goss orientation. However, such an integration degree is preferable for the present invention.

  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, the effect of improving the magnetic flux density can be further obtained. The X-ray random intensity ratio is the ratio of the X-ray diffraction intensity of {100} <011> of the measured sample to the {100} <011> X-ray diffraction intensity of the sample having a random orientation in the X-ray diffraction measurement. Value.

  The {200} texture integration degree of the {200} texture can be measured by X-ray diffraction using MoKα rays. More specifically, for each sample, eleven orientation planes ({110}, {200}, {211}, {310}, {222}, {321} with α-Fe crystals parallel to the sample surface. , {411}, {420}, {332}, {521}, {442}), and the values obtained by dividing the measured values by the theoretical integrated strength of the sample having a random orientation. The ratio of {200} strength to is obtained as a percentage.

For example, {200} intensity ratio is expressed by the following equation (4).
{200} surface integration = [{i (200) / I (200)} / Σ {i (hkl) / I (hkl)}] × 100
... (4)
However, the symbols are as follows.
i (hkl): Measured integrated intensity of {hkl} plane in the measured sample I (hkl): Theoretical integrated intensity of {hkl} plane in a sample with 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.

Next, the manufacturing method of the Fe-type metal plate of this invention is demonstrated. In the method described below, similarly to the manufacturing methods described in Patent Documents 1 and 2, the metal plate is subjected to a heat treatment that is heated to A3 point or higher and then cooled, and in the course of the heat treatment, the ferrite-forming elements are placed inside the metal plate. To form a region of an α-Fe single-phase component system in which the ferrite-forming elements are concentrated, and a technique for increasing the {200} plane integration degree after heat treatment is used.
Below, it demonstrates in order of preparation of a base metal plate, and heat processing of a base metal plate.

[Preparation of base metal plate]
As the base metal plate, a metal plate containing an austenite-forming element, in which strain is introduced into the surface layer portion, is used. This is because, when the base metal plate is recrystallized, a large number of crystal grains whose plane parallel to the rolling surface is oriented in {100} are generated, and the {200} plane integration degree of the α-Fe single phase is improved. For example, it is preferable to introduce a working strain with a dislocation density of 1 × 10 ¹⁵ m / m ³ or more and 1 × 10 ¹⁷ m / m ³ or less. A method for generating such strain is not particularly limited, but for example, it is preferable to perform cold rolling at a high reduction rate, particularly a reduction rate of 97% to 99.99%. 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 the upper and lower rolling rolls at different speeds during cold rolling. In this case, the greater the difference in rotational speed between 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.

[Ferrite-forming element adhesion]
(Types of ferrite-forming elements)
A ferrite forming element other than Fe is diffused in the base metal plate in which strain is accumulated, and the {100} region is increased in the thickness direction of the steel plate.
Therefore, a ferrite-forming element is deposited as a second layer on both surfaces of the base metal plate, and the region where the element is diffused and alloyed becomes an α-Fe single-phase component, and the {200} plane integration degree {100} oriented buds to increase
As such a ferrite generating 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.

(Ferrite-forming element adhesion method)
As a method of attaching the ferrite-forming elements in layers to the surface of the base metal plate, there are various methods such as plating methods such as hot dipping and electrolytic plating, dry clad methods, PVD and CVD, and powder coating. Can be adopted. A plating method or a rolling clad method is suitable as an efficient method for attaching a ferrite-forming element for industrial implementation.
The adhesion thickness of the ferrite-forming element before heating is preferably 0.05 μm or more and 1000 μm or less. If the thickness is less than 0.05 μm, a sufficient {200} plane integration degree cannot be obtained. Moreover, when it exceeds 1000 μm, even when the adhered ferrite-forming element remains on the surface, the thickness becomes thicker than necessary.

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

The base metal plate is further heated and held at a temperature of 1300 ° C. or lower.
In the already alloyed region, the α-Fe single-phase structure does not undergo γ transformation, so the {100} crystal grains are preserved as they are, and {100} grains preferentially grow in the region and the {200} plane The degree of integration increases.
However, if the holding temperature is high or the holding time is too long, the transformation from the γ phase to the α phase is likely to proceed, and it is difficult to form a region in which the austenite-generating element is concentrated inside the coarse grain structure. Therefore, according to the composition of the base metal sheet, the holding temperature (temperature including less than A3 point) and holding time are adjusted, and Al diffusion, orientation into {100} grains, and grain growth of {100} grains are performed. stop.

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

  Further, the present invention is a region in which the austenite-generating element is concentrated inside the coarse grain structure, and does not improve the {200} plane integration degree of the α-Fe single phase over the entire plate. When the {200} plane integration degree of the Al alloyed region is 30% or more and 99% or less by heating the metal plate to A3 point of the base material, the base metal plate is heated at less than A3 point, You may hold | maintain or you may abbreviate | omit the process of heating and hold | maintaining a base material metal plate to the temperature of 1300 degrees C or less.

  The austenite-enriched region forms a ferrite-forming element coating on the plate surface, diffuses the ferrite-forming element toward the center of the plate thickness by heat treatment, and the ferrite-forming elements alloy or crystal grows thereby. As a result, the austenite-generating element contained in the Fe-based metal plate is extruded from the plate surface toward the center of the plate thickness and formed.

[Cooling after heat diffusion treatment]
In the region where Al is not alloyed after the diffusion treatment, normally, a crystal oriented in {100} grows greatly during the transformation from the γ phase to the α phase during cooling. When cooled in a state having a concentrated region, crystal growth stops or the progress of crystal growth slows down, and the inner region not alloyed has a fine grain structure. As a result, a high electrical resistivity region is formed by the austenite-generating element and the fine grain structure that increase the electrical resistivity. In the cooling after the diffusion treatment, the cooling rate is not particularly limited, but is preferably 0.1 ° C./sec or more and 500 ° C./sec or less.

  Whether the region of the A layer having an average crystal grain size of 8 μm or more 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 base material It varies depending on the holding time and holding temperature during the heat treatment of the metal plate. In order to form a region having an average crystal grain size of 8 μm or more in the A layer with one crystal grain, the layer is held at a higher temperature for a long time, and cooling to at least the A3 point or less is gradually cooled in the cooling process.

  Thus, from the surface toward the inside, the composition of the A layer has an area where the average crystal grain size is 8 μm or more and the {200} plane integration degree is 30% or more. An Fe-based metal plate having a crystal grain size of less than 8 μm and a high electrical resistivity region can be obtained.

Next, examples of the present invention will be described. The conditions in the examples are one example of conditions used for confirming the feasibility and effects of the present invention, and the present invention is based on this one example of conditions. It is not limited. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.
Further, in the examples, the configuration of the region in the plate thickness direction is symmetric from the center of the plate thickness. Therefore, unless otherwise specified, the numerical value defining the region in the plate thickness direction is measured on both plate surface sides. Display the averaged value. Numerical values such as magnetic properties are measured values on the metal plate itself.

Example 1
The influence of the composition of the base metal sheet was examined. The ingot was cast by melting so as to have the component composition shown in Table 1 (the balance being Fe and inevitable impurities). The ingot was hot-rolled to a thickness of 50 mm in the γ region, and subsequently processed warm or cold to obtain a base metal plate.

Next, the film elements (ferrite-forming elements) shown in Table 2 were attached to both surfaces of the base metal plate. In addition, the thickness of the film | membrane element shown in Table 2 shows the thickness coat | covered on one side. The film element was attached by an ion plating method or a plating method. Next, the base metal plate to which the film element was adhered was heat-treated at the holding temperature and holding time shown in Table 2. 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 structure of the obtained Fe-based metal plate, the thickness of the α-Fe single phase, the layer structure of the coarse grains, the thickness of the region where the average crystal grain size in the B layer is less than 8 μm, the magnetic properties, and The evaluation results of electrical characteristics are shown.
About the structure | tissue, the {200} plane integration degree and the X-ray random intensity ratio of {100} <011> were calculated | required by the X ray diffraction method.

The thickness of the α-Fe single phase was determined by measuring the composition of the metal plate in the plate thickness direction by line analysis using EPMA. The α-Fe single phase is formed in two layers on both sides of the austenite enriched region in the plate thickness direction. Since the two layers are equal in thickness, the thickness of one α-Fe single phase is the same. Only the thickness was measured. The coarse-grained layer structure was determined using an optical microscope.
The thickness of the region where the average crystal grain size in layer B is less than 8 μm is obtained by conducting a line analysis of the cross section in the plate thickness direction of the metal plate using EPMA, and the concentration of the austenite generating element is the average concentration of the entire Fe-based metal plate. A region having an average crystal grain size of less than 8 μm was determined using an optical microscope.

Regarding the magnetic properties, a sample was cut from a 45 ° direction with respect to the rolling direction, and a magnetic flux density B50 and a saturation magnetic flux density Bs with respect to a magnetizing force of 5000 A / m were measured. In the measurement of the magnetic flux density B50, SST (Single Sheet Tester) was used and the measurement frequency was 50 Hz. In measuring the saturation magnetic flux density Bs, a magnetizing force of 0.8 × 10 ⁶ A / m was applied using a VSM (Vibrating Sample Magnetometer). And ratio B50 / Bs of magnetic flux density B50 with respect to saturation magnetic flux density Bs was computed.
Regarding electrical characteristics, a cross section in the plate thickness direction of the metal plate was subjected to line analysis using EPMA, and a region in which the concentration of the ferrite-forming element was 1.1 times or more the concentration at the plate thickness center of the metal plate, and austenite A region in which the concentration of the generated element is 1.1 times or more of the average concentration of the entire Fe-based metal plate is obtained, and the A layer and the B layer are obtained from the average value of the component composition of each region using the above equation (1). The electrical resistivity was determined.

  As shown in Table 3, each of Invention Examples 1 to 20 has an α-Fe single phase with a coarse grain structure, the thickness of the α-Fe single phase is 0.2 μm or more, and {200} plane integration The degree was 30% or more. In Comparative Examples 1 to 8, although having a coarse grain structure, the {200} plane integration degree was less than 30%. In Invention Examples 1 to 20, the inner region of the coarse grain structure was the austenite concentrated region, and the thickness of the region where the average crystal grain size in the B layer was less than 8 μm was more than 0 and less than 1/20 t. In Examples 2, 4 to 8, a region where the average crystal grain size in the B layer was less than 8 μm was not observed. Moreover, the electrical resistivity of the B layer of Invention Examples 1 to 20 is higher than the electrical resistivity of the A layer. Moreover, the magnetic characteristics of Invention Examples 1 to 20 were higher than those of Comparative Examples 1 to 8, and both high magnetic characteristics and low iron loss could be achieved.

(Example 2)
The effects of the film elements (ferrite-forming elements and austenite-forming elements), the holding temperature and holding time of the heat treatment of the base metal sheet, and the thickness of the austenite-enriched region were examined.
The coating elements shown in Table 4 were attached to both surfaces of the base metal plate. In addition, the thickness of the film | membrane element shown in Table 4 shows the thickness coat | covered on one side. The film element was attached by an ion plating method or a plating method. Next, the base metal plate to which the film element was adhered was heat-treated at the holding temperature and holding time shown in Table 4. 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 structure of the obtained Fe-based metal plate, the thickness of the α-Fe single phase, the layer structure of coarse grains, the thickness of the region where the average crystal grain size in the B layer is less than 8 μm, the magnetic properties, and The evaluation result of electrical resistivity is shown. As in Example 1, in the measurement of the thickness of the α-Fe single phase, the thickness of one of the two α-Fe single phases formed on both sides of the austenite enriched region in the plate thickness direction. Only the thickness was measured.

  In Invention Examples 21 to 40, each has 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%. That was all. In Invention Examples 21 to 40, the region inside the coarse grain structure was the austenite concentrated region, and the thickness of the region where the average crystal grain size in the B layer was less than 8 μm was more than 0 and less than 1/20 t. Moreover, the electrical resistivity of the B layer of Invention Examples 21 to 40 is higher than the electrical resistivity of the A layer.

  Comparative Examples 9 and 15 are cases where an austenite-generating element was adhered to the surface or when a ferrite-generating element was not adhered, the texture could not be controlled, and a high magnetic flux density could not be obtained. It 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 holding time of the heat treatment of the base metal plate are not appropriate, and the average grain size in the B layer The thickness of the region having a diameter of less than 8 μm was out of the range of more than 0 and less than 1/20 t.

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

1 Coarse grain structure 2 Region where austenite-forming elements are concentrated

Claims (2)

Fe-based metal is an average mass% of the whole metal plate, Si: 1.500% or more and 3.500% or less, Al: 0.500% or more and 3.000% or less, and an austenite generating element And Mn: 2.500% or more and 6.500% or less, and Ni: 2.500% or more and 6.500% or less.
Layer A: a region where the concentration of the ferrite-forming element is 1.1 times or more the concentration at the center of the thickness of the metal plate,
B layer: As a region where the concentration of the austenite-generating element is 1.1 times or more of the average thickness of the entire metal plate,
A layer exists on the surface layer side from the B layer at least on one side from the thickness center in the thickness direction of the metal plate,
The electrical resistivity of the B layer is 1.1 times or more of the electrical resistivity of the A layer,
The thickness of the A layer is 0.5 μm or more;
A region of 0.2 μm or all region from the surface of the A layer has a composition of α-Fe single phase, and a region having a composition capable of causing α-γ transformation exists inside thereof.
An average crystal grain size of at least 0.2 μm from the surface of the layer A or the entire region is 8 μm or more,
{200} plane integration degree is 30% or more in the region where the average crystal grain size in the A layer is 8 μm or more,
The average crystal grain size of a part of the B layer is less than 8 μm,
The Fe-based metal plate, wherein the thickness of the region having an average crystal grain size of less than 8 μm in the B layer is more than 0 and less than 1/20 t, where t is the thickness of the metal plate.   In the region where the average crystal grain size in the A layer is 8 μm or more, the surface of the crystal grain forms the surface of the plate, and the grain boundary in the plate of the crystal grain is a partial region of the B layer. 2. The Fe-based metal plate according to claim 1, wherein the Fe-based metal plate has a boundary with a region having an average crystal grain size of less than 8 μm.

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