JPH01252727A - Double oriented silicon steel sheet and its production - Google Patents

Abstract

PURPOSE:To easily manufacture the title steel sheet which has a grain structure having specific texture, reduced in iron loss, and increased in magnetic flux density on an industrial scale, by allowing a rho-alpha transformation to occur in the course of the progress of the decarburizing annealing of a cold rolled silicon steel sheet prepared under specific process conditions and containing the prescribed components. CONSTITUTION:A silicon steel sheet containing, by weight, 0.02-1% C and 0.2-6.5% Si is cold-rolled twice or more, while process-annealed between the above cold rolling stages, under the conditions of >=10% draft in the first rolling and 40-75% draft in the final rolling, by which a cold rolled silicon steel sheet of 0.05-5mm thickness is prepared. Subsequently, this steel sheet is decarburized and then subjected to decarburizing annealing at a temp. where an alpha-pherrite single phase is essentially formed until <=0.01% C content is reached, by which a double oriented silicon steel steet excellent in soft-magnetic properties and having a texture which consists of columnar crystalline grains grown in a direction perpendicular to the sheet surface from the surface toward the inner part and in which average diameter in a direction parallel to the sheet surface is regulated to <=1mm and also the {100} plane is in parallel with the sheet surface and the <001> axis is highly integrated in the rolling direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bidirectional silicon steel sheet with excellent soft magnetic properties and a method for manufacturing the same.

[Prior Art] Silicon steel plates have conventionally been used for magnetic cores of electric motors, generators, transformers, etc. The magnetic properties required of this silicon steel plate are two things: low magnetic energy loss (iron loss) in an alternating magnetic field, and high magnetic flux density in a practical magnetic field. In order to achieve these, it is considered effective to increase the electrical resistance and to integrate the <ioo> axis of the bcc lattice, which is the direction of easy magnetization, in the direction of the used magnetic field.

When the direction of the used magnetic field is limited to one direction, a unidirectional silicon steel sheet containing about 3% St exhibits the best magnetic properties.

This is because, as shown in Figure 7 (a), the +1101 plane is parallel to the plate surface and the <100> axis is concentrated in the rolling direction, so the magnetic properties when used with a magnetic field applied in the rolling direction are Remarkably superior. However, this unidirectional silicon steel sheet is difficult to magnetize in directions other than the rolling direction, so it is not very effective when magnetic fields act in various directions within the sheet surface, such as in rotating equipment such as electric motors and generators. cannot be obtained.

When a magnetic field acts in a plurality of directions within the plane of the plate, a silicon steel plate having a texture as shown in FIGS. 7(b) to (e) is used.

Among these silicon steel sheets, the one that shows good magnetic properties is
As shown in FIGS. 2(B) to 2), the [1001 plane is parallel to the plate surface and the <100> axis is integrated in the direction perpendicular to the plate surface. With such a set ll1a, up to two of the three mutually orthogonal <100> axes will be parallel to the plate surface. Then, two <100 parallel to the plate surface
>The desired degree of axle accumulation varies depending on the application.

For example, a magnetic field is applied in two directions perpendicular to each other within the plate surface.
In the case of an L-type iron core, it is preferable to use a bidirectional silicon steel plate having the texture (1001<OO1>, +1001<011) shown in No. 71; i (b) and (c).
If the magnetic field is applied in all directions within the plate plane, use one with a 1001 in-plane non-directional texture as shown in Figure 7), or use one with a 1001 in-plane non-directional texture as shown in Figure 7 (B) and (C).
01<OO1), [1001<Ol l) It can be said that it is preferable to punch out pieces of agglomerated Mi weave at different angles within the plane of the plate and use them in layers.

Silicon steel sheets with <100> axes in the direction perpendicular to the sheet surface can be produced by methods using solidification structures, high-temperature annealing, and cooling from the austenite (hereinafter referred to as T) single-phase temperature range. It is known that it can be manufactured using three methods.

Method using O solidification structure When steel is solidified, crystals with the HOO> axis in the direction of heat flow grow. When solidified into a plate shape, the direction of heat flow is perpendicular to the plate surface, which is the cooling surface, and the <100> axis is oriented in this direction. Methods using solidified structures take advantage of this orientation, and specifically there are two methods: one using a molten metal quenching method and the other using ingot columnar crystals.

The molten metal quenching method is a method in which molten metal is injected onto the surface of a cooling roll rotating at high speed to directly produce a thin plate with a thickness of about 0.05 to 0.5 mm. With this method, about 6% S
When a silicon ribbon containing I is produced, a columnar grain structure having a long axis in a direction perpendicular to the plate surface or inclined at 20 to 30 degrees with respect to the perpendicular direction is obtained.

In the method of using ingot columnar crystals, a columnar crystal ingot with a (001) fiber structure manufactured by a special casting method is rolled so that the fI O01 side becomes the rolling surface, and 100
A silicon steel sheet having a flool <001> texture is produced by annealing at a temperature of 0° C. or higher.

○ Method using high-temperature annealing The following two methods are well-known in which crystal grains with <100> axes are grown in the direction perpendicular to the plate surface by high-temperature annealing.

One is a method that mainly specifies the annealing atmosphere.
Annealing is performed at a temperature of 0°C or higher. According to this annealing, after the crystal grains have once grown to a size comparable to the thickness of the plate, crystal grains with a (100> axis) preferentially grow in the direction perpendicular to the plate surface using surface energy as a driving force.

The other one is silicon steel with a trace amount of helium added to Oo and 90.
This is a method in which rolling is performed in the direction of 1150°C (cross rolling) and final annealing is performed at a temperature of 1150°C. According to this method, [100
1<001) orientation crystal grains are obtained by secondary recrystallization.

○ Method by cooling from the γ single-phase temperature range JP-A-53-3
1515 and Japanese Unexamined Patent Publication No. 53-31518, etc., are known.

That is, a wJ plate that essentially does not contain C is heated to the r single-phase region, then slowly cooled, and due to the γ-α ferrite (hereinafter α ferrite is referred to as α) transformation at that time, <100> axes are accumulated.

However, both methods have many problems.

[Invention will solve the problem! I topic]

Among the methods using solidification and l1m, in the molten metal ultra-quenching method, the (100) axis density in the direction perpendicular to the sheet surface is at most 3 to 6 times that of a sheet without orientation, and the sheet thickness accuracy is low. The high space factor required for the 1i magnetic steel sheet cannot be secured.

In the method using ingot columnar crystals, <
100> axes with a high density of 4A, the result is a very large crystal grain structure, and the crystal grains are usually 10 to 100 times the thickness of the plate. For this reason, although the magnetic properties in a static magnetic field are good, the eddy current loss is large in an alternating magnetic field, making it impossible to obtain a sufficiently low iron loss.Also, because a special casting method is used, it cannot be implemented on an industrial scale. It can be said that it is extremely difficult to do so.

All methods using high-temperature annealing have the same problems as the method using ingot columnar crystals.

In other words, whether annealing is performed in a weakly oxidizing atmosphere or cross-rolling is performed, if an attempt is made to increase the degree of integration of <100) axes in the direction perpendicular to the sheet surface, a very large grain structure will result.
Iron loss characteristics deteriorate in an alternating magnetic field.

Furthermore, in the former case where annealing is performed in a weakly oxidizing atmosphere, the temperature is 0.
There is a restriction that it can only be applied to thin sheets of 15 mm or less, and the latter method that performs cross rolling cannot be applied to long thin sheets, so neither of these methods can be considered an industrial method.

Since the method of cooling from the γ single-phase temperature range does not substantially contain C, the St content for magnetic properties is reduced to 1.5%.
By simply adding more than 10%, the γ single-phase temperature range disappears, and γ−α
Metamorphosis becomes virtually impossible.

Furthermore, even with the addition of about 1% of SL, it is necessary to raise the temperature to a high temperature of 1000° C. or higher to raise the Ac transformation point, and the crystal grains inevitably become coarser than 11. Moreover, in this method, the (100>axis density in the direction perpendicular to the plate surface is at most 3 to 7 times that of a random one without crystal orientation, and therefore the magnetic properties are also insufficient.

A method is also known in which similar heating and cooling is performed in an atmosphere containing HzS to improve the NOO) axis density, but because of the cooling from a high temperature of 1100 to 1200°C, the crystal grain size is about 2 to 3 fi. There is a growing problem.

The present invention provides a silicon steel sheet that can solve all of these problems by improving the grain structure, especially (1001<00
1>, flool <011> (7) A bidirectional silicon steel sheet having a texture and a method for manufacturing the same are provided.

[Means to solve the problem]

In the present invention, in the process of decarburization annealing of silicon steel sheets, γ-α
When transformation occurs, a silicon steel plate with a low-iron crystal grain structure with a high concentration of <100> axes in the direction perpendicular to the plate surface and a high magnetic flux density is subject to restrictions such as plate thickness due to high precision plate thickness. This is based on the knowledge that it can be easily produced on an industrial scale without any problems.

That is, the final annealing of conventional silicon steel sheets is usually performed in the α single phase temperature range. On the other hand, cold-rolled silicon steel sheets with an appropriate amount of C added to expand the temperature range of the austenitic phase (γ phase) become α single phase when decarburization is completed.
When annealing is performed in a temperature range of about 0 to 1100°C, for example in a vacuum, which is a non-oxidizing and weakly decarburizing atmosphere, this annealing reduces carbon
Since it contains a sufficient amount of , annealing is performed in the temperature range of α + γ mixed phase or T single phase.

As a result, the region from the surface to a depth of 5 to 100 μm is decarburized, only this part becomes a single α phase, and the inside is a fine α
+T mixed m weave or γ single phase Mi weave 0 e.g. α+
In the case of annealing in the T2 phase temperature range, (
As shown in b), the grains in the α single-phase region on the surface become columnar grains with the central axis perpendicular to the plate surface.

Such a decarburized layer on the surface grows inward only slowly in a weakly decarburized atmosphere, and during this period only the crystal grains of the α columnar grains on the surface that have 100) axes in the direction perpendicular to the plate surface. grows parallel to the plate surface.

As a result, the surface layer has a single α-phase texture in which the NOO) axis is strongly integrated in the direction perpendicular to the plate surface. It is presumed that this grain growth is driven by surface energy. At this stage, the α grains in the surface layer are 30 to 300μ in the direction parallel to the plate surface.
They are columnar grains with a size of about m.

Then, for example, if decarburization is allowed to proceed in a strongly decarburizing atmosphere,
The α grains in the surface layer grow toward the α + γ two-phase region or the T single-phase region inside, and finally, as shown in Figure 1 (b), columnar grains extending from both surfaces toward the inside become thicker than the plate. The α single-phase columnar grains and Il weave collided in the center.

As described above, if T-α transformation is caused in the decarburization process, the +1001 set &lIm grown on the surface will be propagated to the inside by grain growth, and the entire plate can easily be made into [100) set mm. . Furthermore, in the process of grain growth, HO in the direction perpendicular to the plate surface
The degree of integration of the O> axis also improves.

In addition, hot rolling and cold rolling before decarburization annealing have little effect on the degree of accumulation of HOO) axes in the direction perpendicular to the plate surface, but HOO axes parallel to the plate surface. ) For the accumulation of shafts, these rollings, especially cold rolling, have a thick effect (by controlling this, +1001
Textures in <001> orientation or +1001 <011> orientation can be obtained. By cold rolling before decarburization annealing, (1001<001> orientation or (1001
The accumulation of <011> orientation is obtained when the cold rolling rate is in a certain range and the NOO of the grains that form the core of the +1001 texture is obtained.
This is thought to be because the axes of > are concentrated in a specific direction with respect to the rolling direction.

The grain growth mechanism described above was discovered through research conducted by the present inventors.

Furthermore, in such a highly integrated +1001 texture, when the columnar crystals have a diameter of several times the plate thickness or less, eddy current loss is significantly lower than that of conventional ones, and high magnetic flux is generated. It was also found that the density

The bidirectional silicon steel sheet and method for manufacturing the same of the present invention were developed based on this knowledge.

That is, the bidirectional silicon steel sheet of the present invention satisfies C≦O1Q 1
Columnar crystal grains grown from the surface to the inside in the direction perpendicular to the plate surface, made of cold-rolled silicon with a plate thickness of 0.05 to 5 fl, containing wt%, 0.2≦Si≦6.5 wt%. The average diameter of the columnar crystal grains in the direction parallel to the plate surface is less than +1001 <001> orientation or +1001
It has a texture that is strongly concentrated in the <011> direction.

In addition, the method for manufacturing bidirectional silicon steel sheet of the present invention is 0°02≦
For a silicon steel sheet containing C≦1wt% and 0.2≦Si≦6.5wt%, cold rolling is performed two or more times with intermediate annealing in order to obtain a (1001<(101>) texture. The rolling ratio of the first rolling is 10% or more, and the rolling ratio of the final rolling is 40 to 75.
(1001<01, in order to obtain the H texture, the plate thickness O,
A cold-rolled silicon steel plate of S~5 fl is produced, and then this cold-rolled silicon steel plate is decarburized and annealed to C≦0.01wt% at a temperature at which it becomes substantially α single phase after decarburization.

[For production]

Hereinafter, the present invention will be explained in detail in the order of component composition, product sheet thickness, crystal structure, <100) axial density in the direction perpendicular to the sheet surface, cold rolled steel sheet manufacturing method, final annealing, and surface coating, and the effects will be clarified. .

○ Among the constituent components, C affects the γ-α transformation and magnetic properties.
, S l, Mn, kl are important.

C: In order to control the aggregated Ml texture using the γ-α transformation accompanying decarburization in the final annealing, it is necessary to contain 0.02 wt% or more, preferably 0.05 wt% or more in the stage before the final annealing. . The upper limit is 1w to suppress decarburization time.
t%, preferably 0.5 wt% or less, more preferably Q, 3 wt% or less.

At the stage after the final annealing, 0
．． 01 wt% or less, preferably 0.005 wt% or less,
More preferably, it is 0.003 wt% or less.

0.2 wt to ensure 5ill characteristics and mechanical properties
% or more, preferably 0.5 wt% or more, more preferably 1 wt% or more. The upper limit is set to 6.5 wt%, preferably 5 wt%, and more preferably 4 wt% to suppress embrittlement and decrease in magnetic flux density. For T-α transformation, 31 increases the upper limit temperature at which the α-single phase becomes substantially after completion of decarburization, contrary to Mn, which will be described later.

It is desirable to add it in order to increase Mrz electrical resistance and reduce eddy current loss, and to expand the γ phase temperature range and facilitate collective & I weave control using T-α transformation. When added, Q is preferably 5 wt% or more, and 0.8 wt% or more.
More preferably t% or more, but in any case α and T
The maximum amount added is such that the transformation temperature from two phases to α single phase becomes 850° C. or higher after completion of decarburization. This is because when a large amount of Mn is added, the upper limit temperature at which α becomes substantially single phase after decarburization is completed is lowered, and the annealing temperature must be lowered to the bottom. Note that if 5ill is high, a large amount of Mn can be added, but it should not exceed 5wt% in order to reduce the magnetic flux density. Substantially α single phase means MnS,
This means that a trace amount of second phase such as AJN may be present.

A1: Desired to be added to increase electrical resistance and reduce eddy current loss. Further, it may be added as a deoxidizing agent to reduce oxygen in steel during the steel manufacturing stage. but,
Adding a large amount causes embrittlement and lowers the magnetic flux density, so the content should be 3 wt% or less. For the γ-α transformation, Sl
Similarly, the upper limit temperature at which α becomes substantially single phase after decarburization is completed is increased.

Components other than C, Si, and Mn that can be added without impairing the present invention are as follows. Note that since N produces the same effect as C, it may be actively added.

A153wt% W, V, Cr, Co, Nl, Mo≦1wt%Cu≦0.
5 w t% NbS2.5 w t% N ≦o, oswt% S ≦0.5 w t% Sb, Se, As≦0.05 wt% B 50.005 wt% P ≦0.5 v t% O product board Thickness In the present invention, there is no need to set an upper limit on the thickness of the product plate from the standpoint of crystallization and IVIi. However, if the product plate thickness is thick, it will take a long time to decarburize to the inside, and eddy current loss will increase. The size should be 5 tl or less, preferably 1 crane or less, more preferably 0.5 fin or less. The lower limit is sufficiently accumulated (1
The length is set to 0.05 m for 001 set & 11 weave, preferably 0.1 we or more, more preferably 0.15 mm or more.

It is based on the &lI weave in which columnar grains extending from the surface of the O-crystal &II weave sheet towards the inside collide near the center of the sheet thickness, but it also has columnar grains &lvet that penetrate in the thickness direction by further promoting grain growth. However, in order to achieve low iron loss, the average diameter of the columnar crystal grains in the direction parallel to the plate surface should be 1 mm or less, and preferably 0.
．． It is 5 times or less, more preferably 0°35t* or less.

0 N OO in the direction perpendicular to the plate surface +2 under such conditions.
00+ anti-reflection bone strength is determined and expressed as a multiple of the value for the sample without crystal orientation orientation. This value almost matches the actual (100>axis density) in the direction perpendicular to the plate surface, except in the following cases.

(1) When crystal grains have a size of 0.1 m or more and there are not a sufficient number of crystal grains in the X-ray irradiation area.

(2) When the concentration of <100'> axes in the direction perpendicular to the plate surface is very strong, this is generally 10 times or more of the case where there is no orientation.

In the present invention, in order to eliminate the exception of (11, (2)), the ratio of crystal grains having <100> axes within ±5° from the perpendicular direction to the plate surface to the total is divided by the ratio in the case of no orientation. This value is defined as the <100> axial density in the direction perpendicular to the plate surface.This value almost agrees with the measurement by Xi when the degree of integration is small.

In experiments, SEM (Scanning [1lec
F, CP (tEIe-ctron Ch
The orientation of approximately 200 to 300 crystal grains is investigated using crystal orientation analysis based on the annelling pattern), and the <100> axis density in the direction perpendicular to the plate surface is determined.

In the silicon steel sheet according to the present invention, by having the crystal structure extending inward from the sheet surface as described above, <1.00> axes are concentrated at high density in the direction perpendicular to the sheet surface. In order to ensure sufficient magnetic properties, this density is preferably 5 or more, more preferably 8 or more, and even more preferably 15 to 20 or more, expressed as the value defined above.

○ Manufacturing method for cold-rolled steel sheets Cold rolling before decarburization annealing does not substantially affect the accumulation of N OO > axes in the direction perpendicular to the sheet surface, but It has a great effect on the accumulation, and by controlling it, a so-called bidirectional silicon steel plate having an aggregate &fl weave with +1001<Q O1) orientation or +1001 <011> orientation can be manufactured.

11001 In order to provide a set m weave with <001> orientation, cold rolling is performed two or more times with intermediate annealing at a rolling rate of 10% or more in the first rolling and a rolling rate of 40% in the final rolling.
~75%, by doing this, < in the direction parallel to the plate surface.
It is possible to obtain a texture in which the 100> axis is strongly deviated in two directions: the rolling direction and the direction 90° with respect to the rolling direction. If the rolling ratio in the first rolling is less than 10%, the <100> axis in the direction parallel to the plate surface cannot be strongly deviated in the above two directions, and if the rolling ratio in the final rolling is 40%.
If it is less than % or more than 75%, strong deviation in two directions cannot be achieved.

+1001 To impart a <Oll> oriented texture, cold rolling is performed once or twice or more with intermediate annealing at a rolling reduction of 80% or more in the final rolling. 100) The axis can be strongly deviated in the direction of 45° with respect to the rolling direction. If the rolling ratio in the final rolling is less than 80%, <1 in this direction
00> The deviation of the axis is weak (i.e., when cold rolling is performed two or more times, rolling other than the final rolling does not strongly affect the formation of this &llI texture, so the final plate thickness can be adjusted by controlling the rolling rate.

For intermediate annealing, 60% due to the need to cause recrystallization.
The temperature shall be 0°C or higher. The upper limit is 1200 from the point of view of industrial implementation.
The preferred range is 700 to 1000°C.

The production of cold rolled steel sheets usually involves the process of continuous casting - hot rolling - cold rolling, but there are other methods other than continuous casting.
For example, a method may be used in which a thin slab directly solidified to a thickness of 50 mm or less or an ultra-thin plate by the molten metal quenching method is directly or hot rolled and then cold rolled. This refers to rolling at temperatures below ℃.

○ Before final annealing and decarburization, decarburization annealing is performed in a temperature range where the product is a two-phase portion of α and γ or a single γ phase, and becomes a single phase after decarburization, thereby preventing decarburization. The part is annealed at a temperature in the α + γ two-phase region or the γ single-phase region, and while decarburization progresses from the surface, a γ-α transformation occurs from the surface layer toward the inside, and N OO > axis in the direction perpendicular to the sheet surface. A substantially single-phase columnar grain structure in which α is strongly accumulated is obtained. Specifically, in order to improve the annealing efficiency etc., it is preferable to perform the following annealing.

First, in a weakly decarburizing and non-oxidizing or weakly oxidizing atmosphere, for example, in a vacuum of ITorr or less, or at a low temperature with a dew point of less than -20°C, Hl, He, Ne is used.
, Nr, Kr, Xe, Rn, and Nt or in an atmosphere of 214 or more at a temperature of 800° C. or higher to form an α single phase region in a region at a depth of 5 to 100 μm from the plate surface. The annealing time is preferably about 1 to 48 hours. If this annealing is performed in a strongly decarburizing atmosphere or an oxidizing atmosphere, even if decarburization occurs, the direction perpendicular to the plate surface is <100>
Axis does not accumulate.

Next, in a strongly decarburizing atmosphere, for example, in H2 with a dew point of -20°C or higher, or in a gas prepared by adding an inert gas or co, co, to H2 with a dew point of -20°C or higher, 650 to 900
The plate is annealed at a temperature of °C, and the α single phase region formed on the surface layer of the plate is allowed to grow toward the inside of the plate. Annealing time is preferably 5m1
If annealing in a weak decarburizing atmosphere is continued without annealing in a 0 strong decarburizing atmosphere for about 20 hours,
If the board is thick, there is a problem in that it takes a long time.

However, the time required for decarburization strongly depends on the plate thickness, so if the plate thickness is 0.2 fi or less, it does not take much time even if annealing is continued in a weakly decarburizing atmosphere.

Note that the strong decarburization step may be performed in a temperature range where a mixed phase of α phase and cementite is formed when C is added.

Although it is preferable to form an insulating film on the surface of the O surface coating, this step may be performed after final annealing or after annealing in a weak decarburizing atmosphere. After surface coating, annealing is performed in a strongly decarburizing atmosphere.

[Example 1] This is an example of a bidirectional silicon steel plate having a +l O01<OO1) orientation texture.

Vacuum melted ingots with nine types of compositions shown in Table 1 as A to ), intermediate annealing (850°C), and cold rolling (rolling ratio 60%).
A plate of 0t[ was used. After that, each tentatively 1 as the final annealing.
870-1150℃ in a vacuum of 0-'Torr, 3
Weak decarburization annealing was performed for 0 minutes to 24 hours, followed by H process 2.
850°C in an Ar flow with a dew point of +40°C containing 0vo 1%
, strong decarburization annealing was performed for 5 minutes to 5 hours.

CM after final annealing is 0.003wt for all samples
% or less.

After the final annealing, the plate thickness was 21 mm from the surface of each sample.
As described above, the crystal orientation of 300 crystal grains in each sample was analyzed using the ECP method at position 5, and the <100> axis density in the direction perpendicular to the plate surface was determined as a multiple of that without orientation. The average grain size of the crystal grains in the direction parallel to the plate surface was determined from optical microscopic observation. In addition, in order to examine the orientation of the <100> axis with respect to the rolling direction,
Magnetic flux density a B when an external magnetic field of A/m is applied
+.

was measured in the rolling direction. For reference, similar measurements were also performed on a sample with almost no orientation. The results are shown in Table 2 together with the final annealing conditions.

The ingot with the composition has a C content of less than 0.02 wt%, and the manufacturing method using this does not fall within the scope of the present invention, and the ingots with other compositions A, C to 1 all satisfy the manufacturing method of the present invention,
The final annealing conditions also satisfy the manufacturing method of the present invention.

The investigation results for compositions A and C-1 show that both silicon steel sheets have an α-phase columnar grain structure grown in the direction perpendicular to the sheet surface;
Moreover, the <100> axis is strongly concentrated in the direction perpendicular to the plate surface, and the value of B1° is large even in the direction parallel to the plate surface, so <I
It can be seen that the OO> axis is strongly concentrated in the rolling direction.

Note that the cross-sectional structure photographs shown in Figures 2 (a) and (b) are
This is a sample of 0.5 mm17 manufactured by hot forging, hot rolling, and cold rolling of steel having the composition shown in the table. (a) is the stage after this sample has been subjected to weak decarburization annealing at 950°C in vacuum for 9 hours, and (b) is the stage after this annealing, with a dew point of +40°C and 4Qvo1%H! +8 in Ar air flow
The stage after strong decarburization annealing at 50° C. for 30 minutes is shown at ×100 and ×50, respectively.

[Example 2] [In order to investigate the effect of cold rolling on the degree of accumulation in the 1001<001> orientation, an ingot made by melting and casting steel with the composition shown in Table 1 in a vacuum was hot forged. by 10f
After heating this plate to a temperature of 1200°C and hot rolling it into a plate with a thickness of 4 to 1.0 fl, 30 to 80%
After performing the first stage cold rolling at various rolling rates in the range of 30 to 80
A second stage cold rolling was carried out at various rolling ratios in the range of 0.5 mm thick.

The surface of each plate obtained was cleaned by electrolytic degreasing, wound into a coil, and a release material mainly composed of A1.01 was filled between the eyebrows, followed by final annealing at 950°C in a vacuum of 1O-47orr for 55 minutes. After time annealing, the coil was subsequently unwound and annealed at 825°C for 2 hours in a 20VOI% H, -Nt gas stream with a dew point of +10°C.

Regarding the obtained sample, N 00 in the direction parallel to the plate surface
) 100OA in the rolling direction to investigate the degree of axle accumulation.
The magnetic flux density B1° was measured when a magnetic field of /m was applied. Also, the iron loss W when magnetized to 1.57 in an alternating magnetic field of 50H2. was also measured.

The results are shown in Table 3 and Figure 3, and Figure 4 shows the set &I! This is a (200) pole figure obtained by removing the surface by polishing to a depth of 215 of the plate thickness and measuring the surface by X-ray diffraction in order to examine the texture.

As is clear from these results, when the rolling ratio in the first rolling is 10% or more and the rolling ratio in the final rolling is 4%,
When it is 0 to 75%, B1° reaches 1.70 or more. From the results in Table 3 and Figure 4, in the direction parallel to the plate surface, <100> axes are strongly concentrated in the rolling direction, and (100>
&l1 where 01 is parallel and <001> axes gather in the rolling direction
It can be seen that m is obtained. It is also seen that the iron loss value also decreases due to the formation of such a texture.

Table 3 [Example 3] (This is an example of a bidirectional silicon steel plate having a set of 1001<011> orientations &[l weave.

Vacuum melted ingots with 10 different compositions shown as A-J in Table 4 were hot forged into 15 mm thick plates, and each plate was 5 m thick.
After hot rolling to a thickness of m, cold rolling (rolling ratio of 86%) was performed to obtain a plate having a thickness of 0.7 mm. Thereafter, each temporary annealing was performed in a vacuum of 10-"w l O-'T o r r as a final annealing.
Weak decarburization annealing is performed at 70 to 1150°C for 10 minutes to 24 hours, followed by H! N with dew point +10℃ containing 20VOI%
Strong decarburization annealing was performed at 825° C. for 5 minutes to 10 hours in one air flow.

The amount of C after final annealing is 0.003wt for all samples.
% or less.

After the final annealing, the plate thickness was 21 mm from the surface of each sample.
As mentioned above at position 5, the crystal orientation of 300 crystal grains was measured for each sample using the ECP method, and the <100> axis density in the direction perpendicular to the plate surface was determined as a multiple of that without orientation. The average grain size of the crystal grains in the direction parallel to the plate surface was determined from optical microscopic observation of the structure. In addition, in order to examine the orientation of the H00) axis in the direction of 45° with respect to the rolling direction, 1
Magnetic flux density B when applying an external magnetic field of 000 A/m,
. was measured in the 45° direction.

For reference, similar measurements were also performed on a sample with almost no orientation. The results are shown in Table 5 along with the final annealing conditions.

The ingot of composition J has a C content of less than 0.02 wt%, and the manufacturing method using it does not fall within the scope of the present invention.All other ingots of composition A-1 satisfy the manufacturing method of the present invention, and the final annealing is The conditions also satisfy the manufacturing method of the present invention.

The investigation results for compositions A to ■ show that all silicon steel sheets have a columnar grain structure of α phase that grows in the direction perpendicular to the sheet surface, and the H00> axis is strongly concentrated in the direction perpendicular to the sheet surface, and Also, the <100> axes are strongly concentrated in the direction of 45° to the rolling direction.

[Example 4] +1001 In order to investigate the influence of cold rolling on the degree of accumulation in the <011> orientation, an ingot produced by melting and casting steel with the composition shown in Table 1 as E in a vacuum was hot forged. 1
A plate with a thickness of 0fl is used, and the plate is heated in a temperature range of 1200 to 900°C. After hot rolling into a plate with a thickness of O ~ 0.5 mm, 7
Cold rolling was carried out at various rolling ratios ranging from 0 to 90%.
, a plate with a thickness of 3n.

Each plate obtained was coated with 0.1 u of Al z ○ and silk powder.
After polishing both sides of about 8 layers and cleaning the surface by electrolytic degreasing, final annealing was performed in a 97° C.
Annealed at 5℃ for 5 hours, followed by 5Q at dew point +5℃
vO1%Hz N! Annealing was performed at 800° C. for 2 hours in a gas stream.

Regarding the obtained sample, <ioo in the direction parallel to the plate surface
＞45 in the rolling direction to investigate the degree of axle accumulation.
Magnetic flux density B when a magnetic field of 100 OA/m is applied in the direction of deviation. was measured in the direction of 45° with respect to the rolling direction. Also, the iron loss W when magnetized to 1.5T in a 50Hz alternating magnetic field, ! ,,. was also measured.

The results are shown in Table 6 and FIG.
Measured by X-ray diffraction at a depth of 15 (200
It is a one pole figure.

As is clear from these results, when the rolling reduction in cold rolling is 80% or more, B. reaches 1.70 or more. From this, in the direction parallel to the plate surface, <100>
It can be seen that the axes are strongly stacked in the direction of 45° with respect to the rolling direction, resulting in a high stacking density (1001<011> set &lt; weave).

It is also seen that the iron loss value also decreases due to the formation of such a texture.

Table 6 [Effects of the Invention] As is clear from the above description, the present invention provides a bidirectional silicon steel sheet with excellent soft magnetic properties. In addition, no special techniques are required in terms of material or rolling, so it is easy to implement and has low implementation costs.Furthermore, it is possible to use the normal cold rolling method, so the steel plate is made of 81 layers with high plate thickness accuracy. The accumulation rate in the state also improves. Furthermore, since decarburization is used, the steel sheet contains sufficient C before decarburization. For this reason,
Even if Sl is added to ensure magnetic properties, the T-α transformation is less affected and the magnetic properties are even better.

Therefore, the present invention improves the properties of bidirectional silicon steel sheets and reduces manufacturing costs by implementing them on an industrial scale,
This has great industrial effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the structure of a silicon steel sheet according to the present invention, FIG. 2 is a photograph of the cross-sectional structure, FIGS. 3 and 5 are charts showing the relationship between cold rolling reduction and magnetic flux density, and FIGS. 6th
The figure is the same <(2001 pole figure, Figure 7 is a schematic diagram showing the crystal orientation of various silicon steel plates. Figure 1 (A) ζ> 2 ) ζ; (A) (B) Figure 3, second stage Rolling ratio (〃) Fig. 4

Claims (1)

[Claims] 1. C≦0.01wt%, 0.2≦Si≦6.5wt%
A cold-rolled silicon steel plate with a thickness of 0.05 to 5 mm containing
Consisting of columnar crystal grains that grow from the surface to the inside in the direction perpendicular to the plate surface, the average diameter of the columnar crystal grains in the direction parallel to the plate surface is 1 mm or less, the {100} plane is parallel to the plate surface, and 001〉A bidirectional silicon steel sheet with excellent soft magnetic properties and a texture in which the axes are strongly integrated. 2, C≦0.01wt%, 0.2≦Si≦6.5wt%
A cold-rolled silicon steel plate with a thickness of 0.05 to 5 mm containing
Consisting of columnar crystal grains that grow from the surface to the inside in the direction perpendicular to the plate surface, the average diameter of the columnar crystal grains in the direction parallel to the plate surface is 1 mm or less, the {100} plane is parallel to the plate surface, and 011〉A bidirectional silicon steel sheet with excellent soft magnetic properties and a texture in which the axes are strongly integrated. 3, 0.02≦C≦1wt%, 0.2≦Si≦6.5w
A silicon steel plate containing t% is cold rolled two or more times with intermediate annealing at a rolling rate of 10% or more for the first rolling and 40 to 75% for the final rolling to achieve a plate thickness of 0. .05
A cold rolled silicon steel plate of ~5 mm is produced, and then this cold rolled silicon steel plate is decarburized and annealed to C≦0.01wt% at a temperature at which it becomes substantially α-ferrite single phase after decarburization. A method for manufacturing a bidirectional silicon steel sheet having excellent soft magnetic properties as set forth in claim 1. 4, 0.02≦C≦1wt%, 0.2≦Si≦6.5w
By performing cold rolling once or twice or more with intermediate annealing at a rolling rate of 80% or more in the final rolling, a silicon steel plate containing t% can be cold rolled to a thickness of 0.05 to 5 mm. A silicon steel plate is produced, and then the cold rolled silicon steel plate is heated to C≦0.0 at a temperature at which it becomes substantially α-ferrite single phase after decarburization.
The method for producing a bidirectional silicon steel sheet with excellent soft magnetic properties according to claim 2, characterized in that decarburization annealing is performed to 1 wt%. 5. A patent claim characterized in that weak decarburization annealing is performed in a non-oxidizing or weakly oxidizing atmosphere at a temperature at which a two-phase mixture of α-ferrite and austenite or a single phase of austenite is obtained. A method for producing a bidirectional silicon steel sheet having excellent soft magnetic properties according to item 3 or 4. 6. Due to weak decarburization annealing, the area of 5 to 100 μm from the plate surface has α
Claim 5, characterized in that decarburization is performed until a single phase of ferrite is obtained, and then strong decarburization annealing is performed until α-ferrite grains in the surface layer collide at least in the center of the plate thickness.
A method for producing a bidirectional silicon steel sheet with excellent soft magnetic properties as described in 2.