JPH0762501A - Grain-oriented silicon steel sheet having excellent magnetostrictive characteristic - Google Patents

Abstract

PURPOSE:To produce the grain-oriented silicon steel sheet for a low-noise core having extremely small magnetostrictions by unifying the crystal directions of the respective crystal grains in the steel sheet to a specific direction and forming films for application of tension on the steel sheet surfaces. CONSTITUTION:After the surface scale of the low-carbon hot rolled steel sheet is removed by pickling, the steel sheet is cold rolled to a cold rolled sheet which is then annealed at 830 deg.C and is cold rolled to a final thickness of 0.28mm. A particulate dispersion of a multicomponent oxide consisting of an alumina sol and boric acid and having an ability to impart tension to the cold rolled steel sheet is applied on the surfaces of the cold rolled steel sheet and the coating is dried to form the films to 0.2mum thickness; thereafter, the films are baked at 850 deg.C. The grain-oriented silicon iron sheet which is unified in the crystal bearings of the respective crystal grains in the steel sheet to the {110} <001> orientation, has 5X10<-6> magnetorestriction when excited to 1.9T in 50 Hz AC and has the extremely small magnetostrictions to be the main cause for noise is thus obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unidirectional electromagnetic iron plate having excellent magnetostrictive properties.

[0002]

2. Description of the Related Art Iron and steel materials having excellent magnetic properties are generally used for the iron core material of transformers, the magnetic core material of electromagnets, and the shield material. High magnetic flux density, high magnetic permeability, and low coercive force lead to weight reduction of iron cores, stronger electromagnets, higher sensitivity of electronic devices, etc. Bring Since iron has a high saturation magnetic flux density, it is suitable for the above-mentioned applications and has been widely used.

Since pure iron-based steel materials have high saturation magnetic flux densities, they have been often used for applications in which a core is formed by laminating or winding and used with a high excitation magnetic flux density. However, when excited with a high magnetic field in order to utilize the high saturation magnetic flux density of pure iron, extremely loud noise was generated, which often became a problem. The main source of noise is the expansion and contraction of the material due to magnetostriction that occurs when the iron core material is magnetized. In the case of conventional pure iron-based materials, the value of this magnetostriction is large, and when a large amount of noise is generated, sound cannot be heard by humans by providing soundproofing means.

On the other hand, however, the larger the core such as the iron core is, the more noise is generated, and the soundproofing device is also bulky and costly. Further, if a soundproof device is attached to a vehicle transformer or the like, noise is reduced, but not only the vehicle weight becomes heavier by the weight of the soundproof device, but not only the fuel consumption is lowered, but also speeding up is hindered.

[0005]

In the present invention, the value of magnetostriction, which is the main cause of noise when used as a core by laminating or winding, is made much smaller than that of a conventional pure iron-based steel material. The present invention provides a unidirectional electromagnetic iron plate having excellent magnetostriction characteristics.

[0006]

The inventors investigated in detail the magnetostriction of various pure iron-based materials. As a result, the crystal orientation of each crystal grain in the iron plate is aligned with the {110} <001> orientation,
Moreover, it was found that magnetostriction is remarkably reduced by forming a coating film that gives tension to the iron plate surface, and the present invention has been completed. The present invention is based on this finding, and the gist thereof is {110} <001>.
It is an iron plate with unidirectionally aligned crystal grains, has a coating film capable of imparting tension to the iron plate, and has a magnetostriction of 5 × 10 5 when excited to 1.9 T by an alternating current of 50 Hz.
^-It is a unidirectional electromagnetic iron plate with excellent magnetostriction characteristics of ^-6 or less.

Here, the meaning that the crystal grains having the {110} <001> orientation are aligned in one direction means that {110} <0
01> Three axes orthogonal to the azimuth (rolling direction, plate surface vertical direction,
It means that the structure is made up of grains having a crystal orientation that is rotated up to 20 degrees around the plate width direction).

The present invention will be described in detail below. The magnetostriction of single crystal pure iron has been measured by many researchers, and it has been reported that the value of magnetostriction varies greatly depending on the domain structure in the demagnetized state (RH Bozorth: Ferromagnetism,
D. Van Nostrand Company, INC. (1951), p.645). For example, according to Kaya et al., The magnetostriction in the <001> direction is about 5 × 10 ^{−6 when} magnetized at DC 2.0T.
According to them, the value is about 16 × 10 ^-6 (ibid., P.64
6).

Further, there has been a long-standing report on a pure iron-based material having excellent unidirectional magnetization characteristics. For example, DM
Kohler (J. Appl. Phys. 38 (1967) 1176) shows that pure iron secondary recrystallized using MnS has extremely excellent direct current magnetization characteristics as compared with conventional iron without orientation control. Is stated. However, there is no example reported so far about what value the magnetostriction has when a pure iron unidirectional material is excited by an alternating current.

Therefore, the present inventors first evaluated the magnetostrictive characteristics of the unidirectional iron plate manufactured by the previously applied technique (Japanese Patent Application No. 1-82236). The measurement was performed on a single plate sample having a length of 300 mm and a width of 60 mm, and the strain of the sample due to magnetostriction was converted into an electric signal by a differential transformer and a relative magnetostriction change was detected as a magnetostriction amplitude. The results are shown in Fig. 1.

At an exciting magnetic flux density of 1.9 T with a large variation, the value of the magnetostrictive amplitude is larger than 5 × 10 ^{-6 and} 9 × 10 ^-6.
The following values are shown. 2 (Al ₂ O ₃ ) for the same material
FIG. 1 shows the results of measuring the magnetostrictive amplitude in the same manner after forming a coating film having B ₂ O ₃ as a main component (having the ability to apply tension to the iron plate). It can be seen that the value of the magnetostriction amplitude is significantly smaller when the film is formed than when the film is not provided, and the maximum magnetostriction value is 5 × 10 ⁻⁶ or less.
That is, the present invention is useful in reducing noise when using a magnetic field characteristic of iron in a high magnetic flux density region design.

[0012]

When the crystal grains having the {110} <001> orientation are aligned in one direction, a 180 ° magnetic domain is formed in the crystal grains, and it is easy to magnetize in that direction. When a material having such a magnetic domain structure is magnetized in its easy magnetization direction,
Almost all of the magnetization is provided by the movement of the 180 ° domain wall. As a result, ideally, the magnetostriction becomes almost zero.

As has been conventionally said, it is considered that the magnetostriction becomes small because the region where the rotational magnetization (actually, the magnetostriction is generated by the movement of the 90 ° domain wall) which causes the magnetostriction is reduced. . It is considered that when tension is applied, the magnetostriction is further reduced because the 90 ° domain wall is further reduced.

In order to apply tension to iron, a coating film having a coefficient of thermal expansion greatly different from that of iron may be formed on the surface. The formation of the film is by a known means. A well-known mixed solution of aluminum phosphate and colloidal silica for silicon steel may be applied to the surface of the steel sheet and dried, or a technique for forming a thin high-strength coating such as PVD, CVD, or ion plating may be used. Is also good.

Since the tension applied to the iron plate is proportional to the thickness of the coating, in the case of a coating containing mainly aluminum and boron, at least 0.2 is required to exert the tension effect.
A coating thickness of at least μm is required. The unidirectional electromagnetic iron plate referred to here is obtained by a known {110} <001> orientation control technique, and contains unavoidable impurities other than iron and an inhibitor element that cannot be completely purified. Inhibitor elements include Al, N, Mn, S,
There are Se, Cu, Sb, etc., and depending on the manufacturing method, 10 ppm to 0.2% may remain in the product.

[0016]

EXAMPLES C: 0.05 wt%, Al: 0.018 wt%,
N: 0.006 wt% and the balance is iron 2 mm
The hot-rolled sheet of 1 was pickled and cold-rolled to 0.8 mm. Annealing was performed at 830 ° C, pickling and cold rolling to 0.28 mm. 830 ° C
Decarburization annealing (in wet hydrogen) and final annealing at 890 ° C. for 10 hours were performed to obtain a cut plate having a length of 300 mm and a width of 60 mm.

Using this material, the magnetostriction amplitude (peak to peak value) was measured at an alternating current of 50 Hz. After measuring the magnetostriction amplitude, a fine particle dispersion containing alumina sol and boric acid was applied, dried and baked at 850 ° C. The magnetostriction amplitude was also measured in the same manner. The results are shown in Fig. 1. It can be seen that the magnetostriction amplitude is significantly reduced by applying the tension film.

[0018]

Industrial Applicability According to the present invention, it is possible to provide an electromagnetic iron plate having an extremely small magnetostriction, which is suitable for manufacturing a low-noise core.

[Brief description of drawings]

FIG. 1 is a chart showing a relationship between a magnetostrictive amplitude and an exciting magnetic flux density.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nao Mogi 20-1 Shintomi, Futtsu City Nippon Steel Co., Ltd. Technical Development Division (72) Inventor Takeo Nagashima 20-1 Shintomi Futtsu City Nippon Steel Co., Ltd. Technology Development Headquarters (72) Inventor Shuichi Yamazaki 20-1 Shintomi, Futtsu City Nippon Steel Co., Ltd.Technology Development Headquarters (72) Inventor Hiroyasu Fujii 20-1 Shintomi, Futtsu Nippon Steel Co., Ltd. (72) Inventor Takao Kanai 1618 Ida, Nakahara-ku, Kawasaki City Nippon Steel Corp. Advanced Technology Research Laboratories

Claims (2)

[Claims] 1. An iron plate in which crystal grains having a {110} <001> orientation are unilaterally aligned, a coating film having a capability of imparting tension to the iron plate is provided on the surface, and an alternating current of 50 Hz is applied. A unidirectional electromagnetic iron plate with excellent magnetostriction characteristics, which has a magnetostriction of 5 × 10 ⁻⁶ or less when excited to 9T. 2. A film capable of imparting tension is a composite oxide mainly containing aluminum and boron and has a thickness of 0.1.
The unidirectional electromagnetic iron plate having excellent magnetostriction characteristics according to claim 1, which has a thickness of 2 μm or more.