JPH05263198A - Double-layered non-oriented silicon steel sheet excellent in magnetic property - Google Patents

Abstract

PURPOSE:To provide a non-oriented silicon steel sheet simultaneously satisfying magnetic properties in low-frequency and high-frequency. CONSTITUTION:The objective double-layered non oriented silicon steel sheet excellent in magnetic properties is in which the components of the surface layer part are constituted of, by weight, <=0.005% C, 2.0 to 4.0% Si, 0.1 to 1.5% Mn, <=0.1% P, <=0.003% S, 0.05 to 2.0% Sol Al and <=0.003% N, and the balance Fe with inevitable impurities and the components of the internal layer part are constituted of <=0.005% C, <2.0% Si, 0.1 to 1.5% Mn, <=0.1% P, <=0.020% S, <=1.0% Sol Al and <=0.003% N, and the balance Fe with inevitable impurities, and in which the ratio of both surface layer part thickness internal layer part thickness is regulated to 0.1 to 0.6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a material for electric products generally used for motors and small transformers, and is especially used for inverters used in a wide frequency range from low frequency to high frequency and non-directional for high frequencies. It is a magnetic steel sheet.
In this field, for example, there are inverter control air conditioners, refrigerator motors, drive motors for electric vehicles, and the like.

[0002]

2. Description of the Related Art In this field, attention has been paid to the fact that inverter control is widely used for improving the energy efficiency of electrical equipment, and the number of equipment for high frequencies is also increasing. The frequency used for these electric devices is 20 to several kHz, and high frequency components are superimposed and used. As described above, the non-oriented electrical steel sheet most suitable for a wide frequency range from low frequency to high frequency has not yet been put on the market. The characteristics required for low frequencies are a small hysteresis loss and a high magnetic flux density for producing a strong rotating torque. What is required in the high frequency range is a small eddy current loss. As described above, since the characteristics required for one electric device differ depending on the frequency, it has heretofore been impossible to use a non-oriented electrical steel sheet having two characteristics.

[0003]

SUMMARY OF THE INVENTION In view of the above points, the inventors of the present invention have made a single steel sheet of a non-oriented electrical steel sheet a composite sheet in order to simultaneously satisfy the required characteristics for both low frequency and high frequency. The idea of layers was newly introduced to complete the invention. The characteristic of this non-oriented electrical steel sheet is that it has excellent magnetic characteristics in a wide range from low frequency to high frequency.

[0004]

That is, according to the present invention, in the weight ratio, the component of the surface layer portion is C ≦ 0.005%, Si: 2.0 to
4.0%, Mn: 0.1 to 1.5%, P ≦ 0.1%, S
≦ 0.003%, SolAl: 0.05 to 2.0%, N
≤0.003%, balance Fe and unavoidable impurities, and inner layer component C≤0.005%, Si: 2.0
%, Mn: 0.1 to 1.5%, P ≦ 0.1%, S ≦ 0.
020%, SolAl ≦ 1.0%, N ≦ 0.003%, and a multi-layer steel sheet comprising the balance Fe and unavoidable impurities, wherein the ratio of both surface layer thickness / inner layer thickness is 0.1.
It is a multi-layered non-oriented electrical steel sheet having excellent magnetic properties, which is characterized by being ˜0.6.

The basic idea of the present invention is to utilize the skin effect and the multilayer structure. As is well known, there is a phenomenon that the penetration of an external magnetic field is reduced in a high frequency region, which is known as a skin effect. At this time, the magnetic flux B inside the steel plate is the magnetic flux B on the steel plate surface.
The depth at which B / Bo = 1 / e with respect to o is called the skin thickness. The skin thickness changes depending on the frequency, the steel sheet permeability and the steel sheet electrical resistance. That is, a large amount of magnetic flux flows in the surface layer in the high frequency region, and eddy current loss also strongly occurs in the surface layer, so a steel sheet having a high electric resistance, that is, a large amount of Si or Al is advantageous. On the other hand, in the low frequency region, the ratio of eddy current loss to total iron loss is small, hysteresis loss is dominant, and the skin effect is weak, so the magnetic flux penetrates the steel sheet almost uniformly. At this time, it is possible to obtain better motor efficiency by increasing the magnetic flux density inside the steel sheet, that is, by making the inner layer of the steel sheet low Si and low Al.

That is, the composition of the outer layer and the inner layer is controlled in an inverter motor or the like which is required to satisfy both the low iron loss in the high frequency range and the high magnetic flux density in the low frequency range at the same time. Multi-layer steel sheets are advantageous.

The present invention will be described in detail below. First, the reasons for limiting the components will be described. The reason why the C content in the surface layer and the inner layer is limited to 0.005% or less is that the magnetic aging deterioration occurs at C content higher than this. The amount of Si in the surface layer is 2.0
Limiting the range to ~ 4.0% is to suppress eddy current loss,
This is because the Si amount required to obtain excellent iron loss at high frequencies is at least 2.0% or more, and 4.0% is the upper limit due to the problem of cold embrittlement. On the other hand, the reason for limiting the amount of Si in the inner layer to 2.0% or less is that it is necessary to obtain an excellent magnetic flux density at low frequencies.

The amount of Mn in the surface layer and the inner layer is limited to 0.1 to 1.5% because if it is less than 0.1%, fine MnS is precipitated and iron loss is deteriorated. The upper limit was 1.5% from the viewpoint. 0.1% P content in the surface and inner layers
In the following, P has the effect of reducing the eddy current loss, but 0.1% was made the upper limit from the viewpoint of the addition cost. The amount of S in the surface layer is limited to 0.003% or less because sulfides deteriorate iron loss at high frequencies, and 0.003%
Is the upper limit. The reason for limiting the amount of S in the inner layer to 0.020% or less is that sulfides also deteriorate iron loss at low frequencies.

The amount of SolAl in the surface layer is 0.05 to 2.0%
The reason for this is that the amount of SolAl required to obtain excellent iron loss at high frequencies is at least 0.05% or more, and 2.0% is the upper limit due to the problem of addition cost. On the other hand, the reason for limiting the amount of SolAl in the inner layer to 1.0% or less is that Al improves iron loss in the low frequency region, but there is a problem of addition cost. The reason why the N content in the surface layer and the inner layer is limited to 0.003% or less is that the nitride deteriorates the iron loss, and 0.003% is the upper limit. As components other than the above, for example, addition of B for reducing AlN or addition of grain boundary segregation type Sb, Sn, etc. for the purpose of improving texture does not impair the gist of the present invention. Next, the reasons for limiting the multilayer structure will be described. The ratio of both surface layer thickness / inner layer thickness is limited to the range of 0.1 to 0.6 because the ratio is 0.1.
This is because if it is below the range, sufficient low iron loss cannot be obtained in the high frequency region. The upper limit is set to 0.6 because if the surface layer is thicker than this, it is meaningless to make a multi-layer steel sheet because it is limited to applications in a relatively low frequency region. Here, the thickness of both surface layer portions is a value obtained by adding the thicknesses of the surface layer portions on both surfaces.

As a method for manufacturing the multi-layered steel sheet, any of known methods such as a casting method, a pressure bonding method and an explosive deposition method may be used. It should be noted that, depending on the manufacturing method of the multiple layers, there are more or less layers in which the surface layer and inner layer components are mixed and diffused in the joint portion. The existence of this diffusion layer does not cause any essential problem in the present invention, and the invention is completed if the components of the surface layer and the inner layer excluding the diffusion layer satisfy the above-mentioned claims. That is, the ratio of both surface layer thickness / inner layer thickness may be counted excluding the diffusion layer thickness.

Further, the total thickness of the product is preferably 0.15 mm to 0.8 mm which is often used as a non-oriented electrical steel sheet. Further, regarding the selection of the surface layer thickness of the upper surface and the lower surface, since the skin effect in the high frequency region is vertically symmetrical, there is no point in making a difference between the upper surface and the lower surface. Therefore, the thickness may be almost the same. Examples of the present invention will be specifically described below.

[0012]

EXAMPLES Table 1 shows the chemical composition of the materials used for the surface layer and the inner layer. Table 2 shows the contents of the experiment and the results when the ratio of the multiple layers was changed. The experimental process was performed by heating a cold-rolled sheet of non-oriented electrical steel sheet containing the components of Table 1 to 700 ° C. by electric current heating, press-bonding under 20% pressure, and making a sheet thickness of 0.5 mm.
It is a magnetic measurement after annealing at 0 ° C. for 30 seconds. The density used for the measurement was obtained by averaging the total amount of Si + 1.7Al in the inner and outer layers, and was calculated according to ASTM A34 (1983).

[0013]

[Table 1]

[0014]

[Table 2]

As described above, the experiment No. in which the multilayer ratio was outside the range of the present invention. In Nos. 1 and 3, the high frequency iron loss and the magnetic flux density are unsatisfactory, respectively. Experiments in which the amount of Si in the surface layer is outside the range of the present invention
No. No. 7 is dissatisfied with high frequency iron loss. Furthermore, in Experiment No. in which the components were out of the scope of the present invention. Since 8, 9, 10, 11, 12 and 13 have many fine precipitates, low frequency iron loss and high frequency magnetic properties are deteriorated. Experiment No., which is a conventional single-layer steel sheet In Nos. 5 and 6, both iron loss and magnetic flux density cannot be satisfied at the same time. Experiment No. satisfying the range of the present invention. Samples 2 and 4 were obtained that satisfied both the magnetic flux density at low frequencies and the high frequency iron loss.

[0016]

As described above, according to the present invention, it is possible to manufacture a non-oriented electrical steel sheet which simultaneously satisfies low-frequency and high-frequency magnetic properties, and it is possible to provide a very useful material especially for an inverter.

Claims (1)

[Claims] 1. A surface layer component in a weight ratio of C ≦ 0.005%, Si: 2.0 to 4.0%, Mn: 0.1 to 1.5%, P ≦ 0.1%, S ≦ 0.003%, SolAl: 0.05 to 2.0%, N ≦ 0.003%, balance Fe and unavoidable impurities, inner layer component C ≦ 0.005%, Si <2.0 %, Mn: 0.1 to 1.5%, P ≦ 0.1%, S ≦ 0.020%, SolAl ≦ 1.0%, N ≦ 0.003%, balance Fe and unavoidable impurities Is a multi-layer steel sheet having a ratio of both surface layer thickness / inner layer thickness of 0.
A multi-layer non-oriented electrical steel sheet having excellent magnetic properties, which is 1 to 0.6.