JPH05275222A - Bidirectional electromagnetic steel plate excellent in magnetic property and laminated iron core - Google Patents

Abstract

PURPOSE:To get a bidirectional electromagnetic steel plate, which has high permeability, and a laminated iron core, which has excellent magnetization property, using its steel plate. CONSTITUTION:These are a bidirectional electromagnetic steel plate high in permeability, which has Fe for its main ingredient and has high integration in {100} <001> azimuth and in which the area percentage of the nonmagnetic second phase exiting within 10mum from the surface of a board in cross section is 5% or less, and a laminated iron core using this steel plate. Hereby, especially the magnetization property under magnetization of a low-intermediate magnetic field improves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grain-oriented electrical steel sheet having excellent magnetic properties and a laminated core.

[0002]

2. Description of the Related Art In iron-based materials, the energy state of electrons bearing magnetism differs depending on the direction with respect to the crystal axis, and is characterized by being easily magnetized in the direction of the Miller index <100> axis. In the unidirectional electrical steel sheet used for the magnetic core of a transformer or the like, this crystal magnetic anisotropy is utilized to obtain a Miller index of {1
10} <001> only crystal grains (called Goss orientation) were selectively grown to dramatically improve the magnetic permeability in one direction in the plane of the steel sheet. This unidirectional electrical steel sheet ({1
In contrast to 10} <001>), a bidirectional electrical steel sheet (Mirror index {100} <001>) in which the <100> axes are oriented in two directions orthogonal to each other in the steel sheet plane has a more ideal soft magnetic property. It is a material. However, the materials reported to date in patents and the like have not been widely used industrially because of insufficient magnetic properties, particularly magnetic permeability.

[0003]

Although the grain-oriented electrical steel sheet has conditions close to ideal as a soft magnetic material, it has a problem that the magnetic permeability is not high enough. In particular, the low magnetic permeability on the low excitation side is a significant disadvantage when used in high-performance electric devices such as high-power actuators. The present invention provides a grain-oriented electrical steel sheet having high magnetic permeability and a laminated iron core having excellent magnetizing characteristics.

[0004]

Means for Solving the Problems The inventors of the present invention can obtain a bidirectional electrical steel sheet having an improved magnetic permeability particularly at a low excitation force by controlling the surface roughness of the steel sheet to a certain value or less. I found it. The present invention is described in detail below.

First, a plate-shaped material containing Fe as a main component and having a high degree of integration in the {100} <001> direction is prepared.
As a component other than Fe, Si is 1.8 to 6.8 by weight.
%, The magnetic permeability improves even under AC excitation, and C
The inclusion of o is advantageous because it increases the saturation magnetic flux density, but it is effective even when these components are not included and is not particularly limited. A plate thickness of 0.8 mm or less is particularly effective, but is not limited to this plate thickness.

Below the surface of the steel sheet, there is a non-magnetic second phase in which the metal component is oxidized or nitrided. The existence form of the second phase is shown in FIG. These non-magnetic second phases impede the movement of the domain wall, and significantly reduce the magnetic permeability especially under the excitation of the low-medium magnetic field. The inventors of the present invention have a cross section perpendicular to the plate surface of the steel plate,
It was found that the magnetic permeability characteristics are improved by controlling the area ratio of the nonmagnetic second phase existing within 10 μm from the plate surface to be 5% or less.

As a method for suppressing the amount of the non-magnetic second phase near the plate surface to a certain value or less, an acid corrosion method using hydrofluoric acid, sulfuric acid, etc., a method using electrolytic polishing, a method of mechanically grinding, A method of purifying annealing in a high-purity atmosphere may be considered, but the method is not particularly limited to one. In the above steps, the area ratio of the non-magnetic second phase existing within 10 μm from the plate surface in the cross section perpendicular to the plate surface is 5% or less, and especially the permeability in the low-medium excitation force is excellent. A grain-oriented electrical steel sheet is obtained.

The above-mentioned bidirectional electrical steel sheet exhibits excellent characteristics when it is used as a magnetic core by laminating thin plate materials. For example, when it is punched into a small EI type core and laminated to be used as a small transformer, it exhibits a high magnetic permeability characteristic especially in a low-medium magnetic field.

[0009]

【Example】

(Embodiment 1) A plate thickness of 0.1% including Si: 3.0% by weight and the balance of Fe and having an orientation close to {100} <001>.
A 35 mm steel plate was corroded for a certain period of time by immersing it in a solution containing 10% by volume nitric acid. The characteristics of the obtained material are shown in Table 1.

[0010]

[Table 1]

(Example 2) A steel plate having an orientation close to {100} <001> with a thickness of 0.8 mm made of Fe and inevitable impurities was mechanically polished. The properties of the resulting material are shown in Table 2.

[0012]

[Table 2]

(Embodiment 3) A steel sheet having a thickness of 0.30 mm and having an orientation close to {100} <001>, which is composed of the balance Fe and contains Si: 3.2% by weight, and an atmosphere of H ₂ : 100% Annealed at 1200 ° C for a certain period of time. The steel plate thus obtained was punched into an E shape to obtain a laminated core. The lapped portion of this laminated iron core was polished, and the core characteristics were measured as an EI core. The characteristics of the obtained iron core are shown in Table 3.

[0014]

[Table 3]

[0015]

INDUSTRIAL APPLICABILITY The present invention improves the excellent magnetization characteristics under the excitation of a low-medium magnetic field.

[Brief description of drawings]

FIG. 1 is a micrograph showing the existence form of a non-magnetic second phase below the surface of a steel sheet.

Claims (2)

[Claims] 1. A main component of Fe is {100} <001>.
It has a high degree of integration in the azimuth direction, and the area ratio of the non-magnetic second phase within 5 μm from the plate surface in a cross section perpendicular to the plate surface is 5%.
The following is a grain-oriented electrical steel sheet with excellent magnetic properties. 2. A laminated iron core obtained by laminating sheet materials cut out from the bidirectional electrical steel sheet according to claim 1.