JP2001303212A - Nonoriented silicon steel sheet excellent in high frequency magnetic property and also having high space factor occupying volume rate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for improving blanking property for increasing the space factor of a nonoriented silicon steel sheet secured with excellent high frequency magnetic properties by a Cr-containing componential system. SOLUTION: In a nonoriented silicon steel sheet having a componential composition containing, by weight, 1.5 to 20% Cr and 2.5 to 10% Si, in which the total content of C and N is reduced to <=100 ppm, and the balance iron with inevitable impurities, the integrated intensity in the 100}<001> orientation in the plane parallel to the sheet face of the steel sheet is <=2.0 times that of the random structure, and also, the sheet thickness is controlled to <=0.30 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-oriented electrical steel sheet having excellent magnetic properties, and more particularly to a non-oriented electrical steel sheet having good magnetic properties when used at a frequency higher than the commercial frequency, and further having a high space factor. Related to electrical steel sheets.

[0002]

2. Description of the Related Art An Fe-Si alloy is known as a material having excellent soft magnetic properties, and is frequently used mainly as an electromagnetic steel sheet having a Si content of 3.5 mass% or less, mainly in various commercial frequency iron cores. However, when the operating frequency is higher than the commercial frequency, there is a disadvantage that the iron loss is increased in the magnetic steel sheet having the Si content of 3.5 mass% or less. Therefore, in order to improve the iron loss characteristics in a frequency range higher than the commercial frequency, a material having higher electric resistance is required.

[0003] Here, if the amount of Si in the steel is increased, the electric resistance increases, which is advantageous in reducing the iron loss in the high frequency range as described above. However, on the other hand, when the amount of Si is 3.5
If it exceeds mass%, the alloy becomes extremely hard and brittle, and the workability is inferior, so that production and processing by rolling become difficult. In particular, when the Si content exceeds 5.0 mass%, not only cold working but also warm working becomes impossible.

[0004] The workability of this high Si steel is improved to 6.5 mass%
As a technique for producing a steel sheet industrially even if it contains a certain amount of Si, a method by hot rolling under low temperature and high pressure disclosed in Japanese Patent Application Laid-Open No.
A method based on the diffusion and infiltration treatment of Si disclosed in Japanese Patent Laid-Open No. 2-227078 is typical.

[0005] However, the former Japanese Patent Application Laid-Open No. 61-166923.
The technology disclosed in the above publication requires fine adjustment of the rolling structure to apparently improve the brittleness of the alloy, and strict control is performed in the manufacturing process, so that it is possible to produce industrially stable products. Is estimated to be difficult. On the other hand, the latter
In the technique disclosed in Japanese Patent No. 227078, a special diffusion infiltration method is used, so that it is considered to be extremely disadvantageous in terms of cost when performing industrial production. Moreover, although there is a limit to further increasing the electric resistance in order to obtain good high-frequency magnetic characteristics, even if the amount of Si is increased by these methods,
It has to stay at the level of at most 80μΩcm. In particular, when the amount of Si is 3.5 mass% or less, which can be produced by a normal industrial rolling method, a specific resistance of only about 50 μΩcm was obtained. In addition, these Fe-Si alloys also have a problem of poor corrosion resistance in applications such as iron cores.

Further, Al has the effect of increasing the electric resistance in the same manner as Si from the viewpoint of magnetic properties, and does not deteriorate the workability as much as Si. It is known that the properties are improved. Al is Si
Although it is more expensive and has weaknesses such as a large decrease in magnetic flux density, for example, steel with a composition of Si: 3 mass% and Al: 0.7 mass% is more workable than steel with a composition of Si: 3.7 mass%. , Good cold rollability and almost the same magnetic properties.

However, in steel of Si: 3 mass% or more,
If the total amount of Si and Al is 4 mass% or more, cold rolling becomes impossible, and if the total amount of Si and Al exceeds 6 mass%, warm rolling becomes difficult. Moreover, also in this case, after all, only a specific resistance of less than 60 μΩcm was obtained industrially.

In any case, rather than simply reducing the iron loss in the high frequency range by simply increasing Si or Al, the alloy according to the new component system having essentially improved workability has a better magnetic property over the higher frequency range. , Ensuring workability,
It is desirable to satisfy corrosion resistance and low cost.

Therefore, the present inventors have proposed Fe-Si alloys and Fe-Si alloys.
-After researching and developing Al alloys to achieve both high specific resistance and good workability of the alloys, we obtained the knowledge that coexistence of Cr is effective, and It has been disclosed in JP-A-11-343544. That is,
Until now, Fe-Si alloys and Fe-Si-Al alloys
It has been thought that the toughness deteriorates with the addition of
Even if the content is 3 mass% or more, it is possible to obtain rather high toughness by sufficiently reducing the content of C and N and then adding a certain amount or more of Cr.
It has been found that the iron loss can be reduced in a high frequency range due to an increase in electric resistance by being contained together with Al and Al. In particular, if the workability at the time of manufacturing is improved, a steel plate having a small thickness can be obtained, so that further improvement in high-frequency magnetic characteristics can be expected.

[0010]

By the way, such a material having excellent high-frequency magnetic characteristics can be further reduced in eddy current loss at a high frequency by reducing the plate thickness, and the iron loss can be reduced. It is essentially advantageous that the thickness is sufficiently smaller than 0.30 mm, mainly 0.20 mm or 0.10 mm, which is sufficiently thinner than the usual non-oriented electrical steel sheets of 0.50 mm or 0.35 mm.

However, in this case, despite the fact that the high-frequency magnetic properties of the material are sufficiently low, the punched material is laminated and actually used as a transformer or high-frequency reactor core. Iron loss sometimes did not reach the expected level from the material. The present inventors examined the cause of the problem, and found that the cause was a problem in that the space factor when the layers were arranged was low, and the main cause was the shape after punching.

Accordingly, the present invention proposes a method of improving the punching property of a non-oriented electrical steel sheet having excellent high-frequency magnetic properties by using a Cr-containing component system in order to increase the space factor. The purpose is to:

[0013]

Means for Solving the Problems In order to improve the punching property of a steel sheet, the present inventors have to appropriately control the texture of the steel sheet and suppress the crystal orientation that inhibits the punching property to a predetermined range. However, they have newly found that they are extremely advantageous, and have completed the present invention.

That is, the gist of the present invention is as follows. (1) Cr: 1.5 mass% or more and 20 mass% or less and Si: 2.5 mass%
% And 10 mass% or less, and the total amount of C and N is 100%.
ppm or less, and the balance is iron and unavoidable impurities. In non-oriented electrical steel sheets, the {100} <001> orientation in the plane parallel to the sheet surface of Non-oriented electrical steel sheet with excellent high frequency magnetic properties and high space factor, characterized in that the thickness is 2.0 times or less of that and the sheet thickness is 0.30 mm or less.

(2) Cr: 1.5 mass% to 20 mass%, S
i: 2.5 mass% or more and 10 mass% or less and Al: 5 mass% or less, reducing the total amount of C and N to 100 ppm or less,
The remainder is a non-oriented electrical steel sheet composed of iron and unavoidable impurities, in a plane parallel to the sheet surface of the steel sheet.
{100} <001> orientation is 2.0 times or less that of the random structure, and the plate thickness is 0.30 mm or less. Electrical steel sheet.

(3) Cr: 1.5 mass% or more and 20 mass% or less;
Si: contains not less than 2.5 mass% and not more than 10 mass%, contains one or two of Mn and P at 1 mass% or less, reduces C and N to 100 ppm or less in total, and balances iron And a non-oriented electrical steel sheet having a component composition of unavoidable impurities, in a plane parallel to the sheet surface of the steel sheet,
The non-directionality with excellent high-frequency magnetic properties and high space factor, characterized in that the integrated strength in the 0｝ <001> direction is 2.0 times or less that of the random structure and the plate thickness is 0.30 mm or less. Electrical steel sheet.

(4) Cr: 1.5 mass% or more and 20 mass% or less, S
i: Including 2.5 mass% or more and 10 mass% or less and Al: 5 mass% or less, containing either one or two of Mn and P at 1 mass% or less, and 100 ppm or less in total of C and N In the non-oriented electrical steel sheet, the balance being iron and unavoidable impurities, the integrated strength of the {100} <001> orientation on a plane parallel to the sheet surface of the steel sheet is smaller than that of the random structure. 2.0 times or less, and the board thickness is 0.30m
A non-oriented electrical steel sheet having excellent high-frequency magnetic properties and a high space factor, characterized by being less than m.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The non-oriented electrical steel sheet according to the present invention will be described first with reference to the reasons for limiting each component range of the component composition. Cr: 1.5 mass% or more and 20.0 mass% or less Cr is a basic element that greatly improves electric resistance by a synergistic effect with Si and / or Al, reduces iron loss in a high frequency range, and further improves corrosion resistance. Alloy component, especially 3.
When containing 5 mass% or more of Si, or 3 mass% or more
Even if it contains Si and more than 1 mass% of Al,
It is extremely effective for obtaining toughness to the extent that it can be warm-rolled, and from that viewpoint, 2 mass% or more is required. When the amount of Si or Al is smaller than the above range, the amount of Cr is 2 mass%.
%, The workability can be ensured, but in order to exhibit the effect of improving the workability of Cr and to make the specific resistance of the alloy 60 μΩcm or more, Cr of 1.5 mass% or more is essential. On the other hand, if the Cr content exceeds 20 mass%, the effect of improving the toughness is saturated and the cost is increased. Therefore, the Cr content is specified to be 1.5 mass% to 20 mass%, preferably 10 mass% or less.

Si: not less than 2.5 mass% and not more than 10 mass% Si is a component effective for significantly increasing electric resistance by a synergistic effect with Cr and reducing iron loss in a high frequency range. However, when the amount of Si is less than 2.5 mass%, even if Cr and Al are used together, a specific resistance of 60 μΩcm or more cannot be obtained without sacrificing much the magnetic flux density. On the other hand, if the content exceeds 10 mass%, the toughness until warm rolling cannot be ensured even when Cr is contained, so that the Si content is 2.5 mass% or more and 10 mass% or less, preferably 7 mass% or less, more preferably 3.5 mass% or less. % Or more 7
mass% or less.

Al: 5 mass% or less Al, like Si, is a component that is effective for significantly improving electric resistance by a synergistic effect with Cr and reducing iron loss in a high frequency range. Therefore, Al can be contained in the present invention as needed.
However, if the amount of Al exceeds 5 mass%, the cost is increased, and the toughness until warm rolling cannot be ensured even with the inclusion of Cr. Therefore, it is necessary to contain Al at 5 mass% or less. On the other hand, the lower limit of Al does not need to be particularly limited.
When about 5 to 0.3 mass% is contained, and when Al is used positively for increasing the electric resistance, it is preferable to contain Al in a range of 0.5 mass% or more. Therefore, Al is 0.
The content is preferably 005 mass% or more, more preferably 0.5 mass% or more and 3 mass% or less.

C and N: 100 ppm or less in total amount C and N must be reduced as much as possible in order to degrade the toughness of the Fe—Cr—Si based alloy.
In order to ensure high toughness under the amounts of Si, Al and Al, it is important to keep the total amount to 100 ppm or less. Preferably, each of C and N is 50 ppm or less, more preferably
30 ppm or less.

The amount of impurities other than C and N is not particularly limited. For example, S is 20 ppm or less, preferably 10 ppm or less, more preferably 5 ppm or less, and O is 50 ppm or less, preferably 30 ppm or less, more preferably Is recommended to be regulated to 15 ppm or less, or to 120 ppm or less, preferably 50 ppm or less in total of impurities C + S + N + O.

1% or less of each of Mn and P by 1% or more respectively Mn and P can further increase the electric resistance by further adding Mn and P to the Fe—Cr—Si alloy. . By the addition of these components, a further reduction in iron loss can be achieved without impairing the spirit of the present invention. However, if these components are added in a large amount, the cost is increased. Therefore, the upper limit of each added amount is 1 mass%. More preferably, each is 0.5 mass% or less.

In the present invention, the addition of a conventionally known alloy component for the purpose of further improving the magnetic properties, corrosion resistance, workability, etc. does not impair the effects of the present invention. It is also possible to include components. Representative examples of those components are listed below.

That is, Ni of 5 mass% or less is a component for improving corrosion resistance, lowers the ductile-brittle transition temperature, improves workability, and easily makes crystal grains fine.
It is effective in suppressing eddy current loss and reducing high frequency iron loss.
Cu of 1 mass% or less has the same effect as Ni. 5 mass%
The following Mo and W improve corrosion resistance. La of less than 1 mass%,
V or Nb, Ti or Y or Zr of 0.1 mass% or less, and B of 0.1 mass% or less have an effect of increasing toughness and improving workability.
Co of 5 mass% or less improves the magnetic flux density and is effective in reducing iron loss. Sb and Sn of 0.1 mass% or less improve the texture and are effective in reducing iron loss.

Further, in the non-oriented electrical steel sheet of the present invention,
Regarding the texture, on a plane parallel to the sheet surface of the steel sheet,
It is important that the accumulation intensity in the {100} <001> orientation be 2.0 times or less that of the random structure. That is, when an electromagnetic steel sheet is processed as a core of a rotating device or a power transformer, the steel sheet is rolled in a rolling direction (hereinafter referred to as an L direction).
Alternatively, punching is generally performed in a direction perpendicular to the L direction (hereinafter, referred to as C direction). It has been newly found that if the degree of integration in the {100} <001> orientation is high in a steel sheet subjected to such a punching process, the magnetic properties when molded as an iron core or a transformer are deteriorated as compared with the material. .
The reason for this is not always clear, but {100} <00
1> The texture of the orientation is the sliding direction of the bcc metal <
111>, it is difficult for shear deformation to occur even when punched in any direction of the L direction and the C direction, and the shape of the punched surface, particularly the drooping shape of the end surface, is deteriorated, and the region is subject to distortion at the time of punching. It is considered that as a result, the deformation (corrugation of the sheet surface) of the steel sheet increases, and the magnetic properties deteriorate due to a decrease in the space factor. Further, in this case, punching distortion is likely to be generated in the steel sheet, and there is a concern that this may deteriorate magnetic properties.

Therefore, the relationship between the texture of the material and the space factor was intensively studied. The result is shown in FIG.
It was found that when the degree of integration of the {100} <001> orientation was 2.0 times or less that of the random structure, the space factor was significantly improved.

Further, as shown in FIG. 1 for each sheet thickness, the deterioration of the magnetic properties due to the increase in the degree of integration in the {100} <001> orientation is more than 0.30 mm. Is less likely to be a problem with the common plate thickness of
The 0 ° <001> direction has an easy axis of magnetization in the L direction and the C direction, which is advantageous for magnetic characteristics. However, as shown in FIG. 1, when the plate thickness became 0.30 mm or less, the above-mentioned problem newly emerged. The reason for this is not clear, but in a thin plate having a thickness of 0.30 mm or less, the adverse effect of {100} <001> texture at the time of punching given by {100} <0.
01> to surpass the effect of improving the magnetic properties by the orientation,
Conceivable. Therefore, in the non-oriented electrical steel sheet of the present invention,
Limit its thickness to 0.30mm or less.

In order to obtain the desired texture in the present invention, the annealing conditions and the rolling reduction during rolling may be appropriately adjusted. For example, a hot rolled electromagnetic steel sheet obtained by a normal process is subjected to one or a plurality of cold or warm rollings sandwiching intermediate annealing with a single pass of a tandem rolling mill or a Zenzimer rolling mill. , When finishing to a predetermined thickness of 0.30 mm or less, if the total draft in the final pass in each rolling is 65% or more, {100} <00
1> A steel sheet having a degree of integration of 2.0 or less times that of the random structure can be obtained.

Here, the degree of integration of a specific orientation indicates how much the frequency of existence of crystal grains having that orientation is relative to a structure having a completely random orientation distribution.
It can be determined as follows. That is, the central portion of the plate thickness parallel to the plate surface of the steel plate sample is polished, and the polished surface is subjected to the (110), (200) and
Measure the incomplete pole figure of (211) as numerical data. This measurement data is described in H. J. Bunge's “Texture Analys
It is converted into a three-dimensional azimuth distribution function using the series expansion method described in "Is Materials Science". If this distribution function is a perfect random distribution, the frequency of occurrence in any azimuth will be 1 To determine the degree of integration of a particular orientation that has been normalized, the orientation, here {100} <
001> The value of the distribution function in the azimuth may be adopted.
This value is correctly a multiple of the degree of integration for the random distribution. Here, the degree of integration in which the deviation angle from the {100} <001> direction was within 15 ° was obtained.

Incidentally, the non-oriented electrical steel sheet of the present invention can be manufactured by the following method. That is, the alloy material adjusted to the above-described component composition range is made into a slab by continuous casting or ingot-bulking rolling. In addition, a thin slab can be manufactured by using a thin slab continuous casting method. The obtained slab is subjected to hot rolling after heating and holding, or continuous casting such as a method of directly feeding and rolling after continuous casting (CC-DR method) or a method of keeping heat after continuous casting (HCR method). While maintaining the sensible heat at the time, it is subjected to hot rolling without heating.

Next, in hot rolling, the workability in the next step of cold rolling or warm rolling, that is, rollability, can be improved by rolling as thin as possible. This is based on the new finding that in the case of the Fe-Cr-Si-based alloy composition of the present invention, the surface portion of the hot-rolled sheet has higher toughness than the central portion and has excellent workability. is there. The thickness of the hot rolled sheet for that purpose is 3 mm or less, preferably 2.
5 mm or less, more preferably 2.0 mm or less.

Since the toughness of the hot-rolled sheet is improved, the sheet can be further rolled hot or cold to obtain a thin sheet having a thickness of 0.4 mm or less. 0.30
mm or less. Then, in this rolling step, an intended texture is obtained by controlling the annealing conditions and the rolling reduction.

By the way, it is well known that, in general, when the plate thickness is reduced, eddy current loss is advantageously suppressed particularly at high frequencies, resulting in low iron loss. However, materials with high electrical resistance have been poorly rollable so far, and 0.5 mm
It was only reduced to the extent. It has also been said that simply reducing the thickness does not allow a sufficient reduction in iron loss due to hysteresis loss. In this regard, in the present invention, it has been found that by selecting the component system and the purity, the effect of the high-frequency iron loss characteristics when the thickness is reduced can be promoted. In order to obtain such an effect of thickness reduction, it is effective to make the plate thickness 0.4 mm or less. However, to make it thinner than 0.01mm,
Due to cost and industrial implications, the range of thickness is 0.01
0.30.30 mm, preferably 0.03 to 0.30 mm.

In the rolling for reducing the thickness,
Because the workability of the material is excellent, it is not always necessary to secure the rollability by annealing the hot-rolled sheet as in the past, or intermediate annealing during cold rolling or warm rolling, especially in the past. , Improving work efficiency by omitting hot-rolled sheet annealing and intermediate annealing,
Energy saving and cost reduction can be achieved. However, when annealing is performed in the middle, for example, a temperature range of 600 to 1100 ° C.
s to about 10 min. Subsequent annealing and surface finishing
The same process as that for a normal electromagnetic steel sheet or an electromagnetic stainless steel sheet can be applied.

[0036]

EXAMPLE A steel slab having the composition shown in Table 1 was hot-rolled to various thicknesses, and then cold-rolled and annealed according to the conditions shown in Table 2 to a predetermined thickness.
Finish annealing at ℃ and semi-organic resin
It was baked at 2.0 g / m ² and an average film thickness of 1 μm to obtain a product plate.

From the product plate thus obtained, a punching process is performed in a size of 280 mm × 30 mm along the L direction and the C direction (die material: SKD-11, punching speed: 60 strokes / min and clearance: 10%). ), The space factor was measured for the test piece in accordance with JIS C2550 (1997). Here, cutting burrs were not removed to match the actual space factor of the iron core. The number of lamination tests was 80 for 0.10 mm thick material and 40 for 0.20 mm thick material.
There were 28 sheets of 0.30 mm thick material and 24 sheets of 0.35 mm thick material.

For each steel sheet, JIS C2550 (1975)
), And the iron loss at a frequency of 10 kHz and a magnetic flux density of 0.1 T was determined. Table 3 shows the measurement results.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

From Tables 2 and 3, it can be seen from Tables 2 and 3 that a steel sheet having a thickness of 0.30 mm or less and having a degree of {100} <001> orientation greater than 2.0 times that of the random structure has a high space factor and a high iron loss. Is low. It can also be seen that when the plate thickness is as large as 0.35 mm, the {100} <001> orientation is not adversely affected.

[0043]

According to the present invention, the conventional Si content of 6.5 mass
% Of non-oriented electrical steel sheet, which has high frequency magnetic properties equal to or higher than that of Fe-Si alloys and Fe-Al alloys in addition to good workability. Can be improved.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the degree of integration of {100} <001> orientation and the space factor.

Continued on the front page (72) Inventor Atsuto Honda 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. (Without address) Inside the Mizushima Works, Kawasaki Steel Corporation (72) Inventor Yuka 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama ( No address) Inside Mizushima Works, Kawasaki Steel Corporation (72) Inventor Masaki Kono 1-chome, Mizushima Kawasaki-dori, Kurashiki-shi, Okayama Prefecture (No address) Inside the Mizushima Works, Kawasaki Steel Corp.

Claims (4)

[Claims] (1) Cr: 1.5 mass% to 20 mass% and Si:
A non-oriented electrical steel sheet containing 2.5 mass% or more and 10 mass% or less, reducing the total amount of C and N to 100 ppm or less, and the balance being the composition of iron and unavoidable impurities. The {100} <001> orientation of the random surface is 2.0 times or less that of the random structure,
A non-oriented electrical steel sheet having excellent high-frequency magnetic properties and a high space factor, characterized by a sheet thickness of 0.30 mm or less. (2) Cr: 1.5 mass% to 20 mass%, Si: 2.
Non-oriented electrical steel sheets containing 5 mass% or more and 10 mass% or less and Al: 5 mass% or less, reducing the total amount of C and N to 100 ppm or less, with the balance being iron and unavoidable impurities.に お け る 10 in a plane parallel to the plate surface of the steel plate
The non-directionality with excellent high-frequency magnetic properties and high space factor, characterized in that the integrated strength in the 0｝ <001> direction is 2.0 times or less that of the random structure and the plate thickness is 0.30 mm or less. Electrical steel sheet. 3. Cr: 1.5 mass% or more and 20 mass% or less and Si:
Containing not less than 2.5 mass% and not more than 10 mass%, containing either one or two of Mn and P at 1 mass% or less;
And N are reduced to 100 ppm or less in total, and the remainder is non-oriented electrical steel sheets having a composition of iron and unavoidable impurities, and {100} <0 in a plane parallel to the sheet surface of the steel sheet.
A non-oriented electrical steel sheet having excellent high-frequency magnetic properties and a high space factor, wherein the integrated strength in the <01> orientation is 2.0 times or less that of the random structure and the sheet thickness is 0.30 mm or less. (4) Cr: 1.5 mass% to 20 mass%, Si: 2.
Contains 5 mass% or more and 10 mass% or less and Al: 5 mass% or less, and each of one or two of Mn and P is 1 ma
ss% or less, C and N are reduced to a total amount of 100 ppm or less, and the balance is a non-oriented electrical steel sheet having a composition of iron and unavoidable impurities. {100} <001> orientation is 2.0 times or less that of the random structure, and the plate thickness is 0.30 mm or less. Electrical steel sheet.