JPS6179722A - Manufacture of grain oriented magnetic steel sheet having superior iron loss property and high magnetic flux density - Google Patents

Abstract

PURPOSE:To obtain the titled steel sheet, by applying precipitation annealing, cold rolling and decarburization annealing to a hot rolled plate of Si steel having a specified compsn., then finish annealing said sheet by using annealing separator agent composed of MgO having specified B content. CONSTITUTION:The hot rolled plate made of Si steel contg. 0.085% C, 2.0-4.0% Si, 0.03-0.15% Mn, 0.01-0.05% acid soluble Al, 0.005-0.010% N, 0.03-0.5% Sn, 0.02-0.3% Cu is precipitation annealed, next, cold rolled to <=0.23mm the final sheet thickness then decarburization annealed. Successively, annealing separator agent composed mainly of MgO having controlled 400ppm B content is coated on said sheet to finish anneal it. By this method, the titled thin steel sheet having high Goss orientation accumulated degree, fine secondary recrystallized grains and superior surface film is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a high magnetic flux density grain-oriented electrical steel sheet with excellent core loss characteristics.

(Prior Art) Grain-oriented electrical steel sheets are soft magnetic materials that are mainly used as iron core materials for transformers and other electrical equipment, and must have good magnetic properties in terms of excitation properties and iron loss properties. In order to obtain a material with good magnetic properties, (1) stz is increased to increase the specific resistance.

(2) Reduce the thickness of the product board.

(3) Reduce the secondary recrystallized grain size of the rust plate.

(4) High precision of GoIIg orientation of secondary recrystallized grains.

etc. can bloom.

The improvement in Gossian density has been greatly improved by the development of the single cold rolling method, and now products with magnetic flux density exceeding 95% of the theoretical value are being manufactured. Along with this, the iron loss characteristics also improved significantly, but it is not possible to further improve the iron loss characteristics by simply increasing the Go8s orientation density.
However, it has become necessary to develop techniques for increasing the resistivity, making secondary recrystallized grains finer, and reducing the thickness of product sheets.

Among these, the refinement of secondary recrystallized grains is an important problem in materials with a high i & final third reduction ratio such as the one-time cold rolling method.
Even though the iron loss characteristics were improved by increasing the degree of integration by 550,000 degrees, there was a problem in that the iron loss characteristics did not improve as expected due to the increase in grain size.

In order to solve these difficulties,
A method was proposed in which Sn was added to silicon steel containing a weight of ALlfr as described in Publication No. 2. Although the purpose of making the secondary recrystallization finer was achieved by adding Sn to the silicon solution containing a small amount of Al, the surface film deteriorated due to this Sn, and the effect of reducing iron loss was not sufficiently achieved. There is a problem that it is not possible to obtain
A method of adding Cu to molten silicon steel containing n was proposed, making it possible to manufacture a high magnetic flux density oriented electromagnetic needle plate with fine secondary recrystallized grains and an excellent surface coating. Ta.

On the other hand, due to the recent rapid rise in energy costs, there is a need to supply high magnetic flux density grain-oriented electrical steel sheets with even better iron loss characteristics.In order to meet this demand, there is a growing trend toward thinner product sheets, In recent years, the plate thickness has changed from 0.3011m to 0.2m.
Even 3 In products are now being manufactured.

(Problems to be Solved by the Invention) However, the above-mentioned silicon steel material with a composite addition of Cu and Sn has excellent magnetic properties and high magnetic flux density directionality when the plate thickness is 0.23 fl or less! In order to produce a single magnetic steel sheet, combined addition of Cu and Sn is essential to obtain fine secondary recrystallized grains and an excellent surface film, but as the sheet thickness decreases, the directionality decreases, which is expected. In some cases, the improvement in iron loss characteristics that was desired could not be obtained sufficiently.

The invention eliminates the problems of silicon steel with a composite addition of Cu and Sn, and produces a product with a thickness of 0.23 μ or less, a high Gosg orientation concentration, fine secondary recrystallized grains, and an excellent surface. The object of the present invention is to provide a method for manufacturing a magnetic steel sheet having a coating and having high magnetic flux density directionality and excellent iron loss characteristics.

(Means for solving problems) The basic configuration of the present invention is as follows.

That is, C: 01085% or less, Sl: 2.0
~4.0jX, Mn: 0.03~0.15%, S:
0.01-0.05%, acid-soluble Al: 0.01-0.0
5%, N: 0.005-0.010%, Sn
: A silicon steel material containing 0.03 to 0.5% + Cu: 0.02 to 0.3% is hot-rolled into a hot-rolled plate with an intermediate thickness, and the hot-rolled plate is subjected to precipitation annealing, Next, a series of high magnetic flux density directional electric 'fJi silver plates were prepared by performing a cold rolling process to reduce the final plate thickness to 0.23 u or less, a decarburization annealing process, an annealing separator coating process, and a final annealing process. A patented high-magnetic-flux-density grain-oriented electrical steel sheet characterized in that, in the manufacturing process, an annealing separator whose main component is MgO with a boron content of less than 400 ppm as boron is used in the annealing separator application step. This is a manufacturing method.

Next, the method of the present invention will be explained in more detail.

First, the basic experimental facts that led to the conclusion of the present invention will be discussed.

(Experiment 1) Inventor FiC: 0.067%, Sl: 32
3%, Mn: 0.07%.

S: 0.03%, acid soluble Al: 0.03%, N
: 0.007%, Sn: 0.1%. Cu: 0
．． A silicon steel material containing 0.09% was hot-rolled to a thickness of 2.0 mm by a conventional method and subjected to precipitation annealing at 1100℃ for 4 minutes, and then a final thickness of 0.30 to 0.081℃m was applied. Cold rolled in the range. Next, this cold-rolled plate was heated at 820°C for 4
After decarburizing annealing in wet hydrogen for minutes, the surface of the copper plate was
The weight of the four-agent slurry used for annealing, which is mainly composed of MgO, after drying is 6? /R, and finish annealing was performed. Finish annealing is first performed at 600℃ in dry nitrogen for 5
soak for dehydration, then 20%N2+8
After raising the temperature to 1200° C. at a rate of 20° C./Hr in 0% H2, the atmosphere was changed to pure hydrogen and purification annealing was performed for 10 hours, and the magnetic properties of the obtained product were examined. This result is the first
As shown in the figure.

(Experiment 2) Additionally, in order to investigate changes in iron loss characteristics due to differences in plate thickness, a product with a plate thickness of 0.30+W manufactured using the above method had a magnetic flux density of B. 1.95 (T), iron loss w171
50 and 0.95 (WAg) was collected, the glass film was removed in hydrochloric acid, and then chemically polished in a phosphoric acid-hydrogen peroxide mixture to reduce the plate thickness, and then heated at 850 °C for 3 The steel plate surface is annealed in wet hydrogen for 1 minute to generate 5I02, and after applying and drying an annealing separation agent containing MgO as a main component, 12 minutes in hydrogen to regenerate the glass film.
000 for 5 hours. The results are shown in (m) in Figure 1.

(see Figure 1), when manufacturing high magnetic flux density directional i magnetic steel plates with different plate thicknesses in the normal process, the plate thickness varies from 0.30 m to 0.2 m.
What is the board thickness up to 0 tm? The iron loss characteristics of the g-shaped steel sheet improve, but when the plate thickness is 0.20 m or less, the thinner the plate thickness, the worse the iron loss characteristics. In addition, the magnetic flux density also decreases when the plate thickness reaches 0.20 mm (the thinner the plate is, the worse the Goss orientation integration degree is).

On the other hand, when a product with a thickness of 0.30 Kll was reduced to a thickness of t by chemical polishing and the glass film was regenerated, the iron loss characteristics continuously improved as the thickness increased to 59 mm. If the secondary recrystallization progresses in the same way, that is, if the GO811 orientation integration degree and surface coating are the same, the thinner the plate, the better the iron loss characteristics. In this case, the secondary recrystallization behavior occurs when the plate thickness is 0.
It can be concluded that this is different from the case of 2011J1 or higher. Therefore, in order to elucidate the cause of the difference in secondary recrystallization behavior depending on plate thickness, the present inventor carried out the annealing separation agent application process under the same conditions as above, and extracted the sample sound during the temperature rise during finish annealing. Among the components in the steel, chemical analysis was conducted on CN, which greatly contributes to secondary recrystallization as an inhibitor.

Figure 2 (,) shows the Total N in the steel, Figure 2 (b
) is precipitated in steel as A7N (N ag
Figure 2 shows quantitative changes in ALN) with temperature. Figure 2(a)
, From (b), when the temperature is raised to about 3 A during final annealing, Total N is around 90010 before the start of secondary recrystallization.
+ Nag Although the difference due to plate thickness is extremely small for both ALN, the temperature is usually 950 to 1050°C, where it is thought that primary Gong due to secondary recrystallization occurs.

Furthermore, at temperatures above 1050°C where Gosm grains develop, the thinner the plate thickness is, the higher the TOta will be.
It was found that the amount of decrease was large for both IN and NJllAIN. Therefore, during the heating process of finish annealing, the strong inhibitory properties necessary for effective secondary recrystallization to proceed at lower temperatures are likely to be lost due to AlN C decomposition at lower temperatures for thinner materials. Ga55 after annealing
It is thought that the degree of azimuth integration deteriorates, and by suppressing the decomposition of this inhibitor, it is expected that the magnetic flux V degree of the thin material can be improved.

The present invention@ has conducted a detailed investigation into the reason why the decomposition of AlN as the inhibitor is more likely to occur at low temperatures in thin I/1 material than in thin I/1 material. (CB in steel)
It was found that the quantity was high. Figure 3 shows the distribution of CB) in the depth direction from the surface layer at 1025°C of the sample obtained in the above experiment, analyzed by IMA (ion micro globe analyzer), and the ion intensity f on the vertical axis.
f is calculated by multiplying the weight by 1.000, and the [B
], and the horizontal axis represents the distance in the depth direction with respect to the plate thickness. As shown in Figure 3, if the board thickness is 0.27mm thick, the CB) will have a background.

It is almost diffused into the steel and is dense, but when the plate thickness is 0.
Diffusion into the steel was clearly confirmed from 23 m onwards, and it was found that the amount of diffusion into the steel with thinner plate thickness (T) [8] increased and the penetration depth also became larger. Also, CB in this steel
) The same sample surface as shown in Figure 3 is held at a constant potential in a non-aqueous solvent! The precipitates were identified using EDX (Enerui dispersive
It turns out that there is something.

From the above facts, as soon as the thin material (CB) diffuses into the steel during the temperature rising process during final annealing to form BN, this BN becomes AAN (s) + Dan = Al + BN ( It is thought that this is produced by the reaction of s), and as a result of the decrease in the dispersed precipitated phase, which acts as an inhibitor for the effective progress of secondary recrystallization, the Go118 orientation integration degree of the product decreases, and the iron This is thought to deteriorate the loss characteristics.

As mentioned above, in the manufacturing process of grain-oriented electrical steel sheets with high insect flux density, in the final annealing process, the 1XA material with a thickness of 1
] has been found to diffuse and deteriorate the magnetic properties, but among the steps from the hot rolling process to the final annealing process, the process in which CB) is supplied to the steel plate surface is usually the annealing separation coating process. Only.

Magnesia, which is used as a general Vc phosphorus dull separator, is a mixture of Mg(OH)2 collected from seawater and 700 to 1
It is produced by firing at a relatively low temperature of 000°C and is called calcined magnesia. Due to the characteristics of its manufacturing method, this calcined magnesia contains unavoidable impurities such as Na'', CL,
For high magnetic flux density electrical steel sheets containing F-, So, "I B, etc., and using AlN as an inhibitor, the presence of CB in the annealing separator is particularly regulated. For example, Japanese Patent Publication No. 46-42298 According to the publication, boron or a boron compound is added to the annealing separator and the IC steel sheet is treated with [B''] during final annealing.
A technique for improving the magnetic properties of products by actively diffusing l is disclosed, but as in the present invention, the plate thickness is 0.23+c+
If it is thinner than below, the magnetic properties will deteriorate on the contrary. Therefore, from the above-mentioned actual results, the steel components include Cu and Sn.
It was found that reducing CB) in the Fi annealing separator in a material with a plate thickness of 0.23 jJ or less that contains CB) is essential for improving magnetic properties, and the present invention was completed.

The present inventor investigated the influence of the amount of CB in the annealing separator on the magnetic properties of the product. First, the decarburization annealing process was performed using the same material and under the same conditions as in the experiment], and then (B) trace fineness 99.9% Mg was used as an annealing separator.
B2O3 as a [B] source was blended with the O slurry as [E] in a ratio of 0 to 11,000pp to MgO, and the steel plate after decarburization annealing ((96P/ff on one side with type i after drying) was added to the O slurry.
It was coated to give a coating thickness of 1' and dried. Next, finish annealing was performed under the same conditions as in Experiment 1 to improve the magnetic properties of the product.

The results are shown in FIG. Figure 4: Plate thickness 0.27 a
For materials with a diameter of m or more, as the CB) content in the annealing separator decreases, the magnetic flux density improves slightly, but the iron loss characteristics cannot be improved because the product crystal grain size increases. -10,000, C in the annealing separator if the plate thickness is 0.23 Nm or less
B) As the i content decreases, the magnetic flux density improves and the iron loss characteristics greatly improve;
It has been found that in a region as small as 0.00 ppm, iron loss characteristics equivalent to the results shown in FIG. 1 obtained for the actual λ2 can be obtained.

Therefore, by making CB)fL in the annealing separator less than 400 ppm, Cu,
Plate thickness 0.23 PIF containing Sn, the following secondary recrystallization progresses effectively, and high magnetic flux density directionality with excellent iron loss characteristics has fine secondary recrystallized grains with Ga55 orientation concentration fR degree 1! A steel plate is obtained, and the object of the present invention is achieved continuously.

Next, the reasons for the limitations of the present invention will be explained.

If CfdQ exceeds 085%, it is not preferable because the post-process decarburization annealing takes a long time.

If the Sl content is less than 20%, the low iron loss which is the object of the present invention cannot be obtained, and if it exceeds -4.0%, cold rolling becomes difficult9, which is not preferable.

Acid-soluble Al is a basic element of Honsho branch system, 0.01~0
If it deviates from the 0.05% range, secondary recrystallization becomes unstable.

Mn and S are elements necessary to form MnS, and the appropriate amount of Mn is in the range of 0.03 to 0.15%, preferably 0.05 to 0.10%. If S exceeds 0.005%, desulfurization during purification annealing becomes difficult, which is not preferable.

On the other hand, at less than 0.01%, MnS acts as an inhibitor.
amount is insufficient.

Sn is 0.03 to 0.5%, preferably 0.05 to 0.0%.
20%, Cu 0.02-0.3%, preferably 0.0
It is in the range of 5 to 0.15%. This is effective in refining secondary recrystallized grains, and if this fL is less than 0.03%, the effect is weak, and if it exceeds -0.5%, it may be combined with Cu, resulting in poor rolling properties. and the pickling properties deteriorate. -10,000, Cu
is an excellent element for forming a glass film, and a film with good adhesion can be obtained, but when added alone, the secondary recrystallized grains become coarse and the core loss characteristics deteriorate. This amount of Ct+ is 0.
If it is less than 0.02%, it will have little effect on improving the glass film, and if it exceeds 0.3%, it is unfavorable from the viewpoint of magnetic properties.

Product board thickness is Q, 23+ut or less, preferably 0.231
Em ~ 0.10 tK is suitable, and for those with a thick plate thickness of 0.23 mm, even after improving the orientation (Go 10,000 degree of integration) and grain size, the iron loss characteristics can be improved more than the current process. It is difficult.

CB] content in annealing separator: 400 ppm
less than 1, preferably less than 1300 ppm,
If it is 400 pprn or more, the degree of Qoss orientation integration of the secondary recrystallized grains is low and the improvement in iron loss characteristics due to the reduction in plate thickness is not favorable.

As mentioned above, the purpose of the present invention is to limit the composition of the mm component in the steelmaking process, the plate thickness in the cold rolling process, and the trace elements in the annealing separator mainly composed of MgO in the annealing separator coating process. However, by combining the method of the first invention with the annealing temperature and atmospheric conditions in the final annealing step, it is possible to produce a high magnetic flux density grain-oriented electrical steel sheet with even better core loss characteristics. I discovered something.

That is, the second invention performs secondary recrystallization in the above-mentioned final annealing step within a temperature range of 780 to 1000°C, and
The method of the first invention is characterized in that the process is completed in an atmosphere that is neutral to Sn and Cu.

It is known that both Sn and Cutd, which are the silicon steel components of the present invention, are useful as inhibitor components for effectively promoting secondary recrystallization. As a result of intensive study on the behavior of Sn and Cu during final annealing, the present inventor found that during final annealing, grain boundary segregation occurs within the 5n)i steel sheet.
Normal grain grow of primary recrystallized grains by dispersing and precipitating Cu F'i and Cux S
th is suppressed (inhibitor effect), Sn is 800~
Cu-S, which is most sensitive to segregation at around 900°C, has a precipitation nose at about 900 to 1000°C, depending on the ratio of Cu and S, and therefore, the precipitation of Sn and CuzS segregation is also easy. The most powerful inhibitor effect is obtained by treatment with temperature overhead, and as a result, fine and Gomu
It was found that secondary recrystallized grains with a high s-orientation concentration yC summer can be obtained. Therefore, the suitable temperature for final annealing is 780 to 1000°C, preferably 800 to 950°C. Below 780°C, it takes a long time to start secondary recrystallization and the growth of secondary recrystallized grains, which is undesirable. If the value exceeds 1, the grain boundary segregation effect of Sn disappears, and the degree of integration of the GO2 orientation of the secondary recrystallized grains becomes low, making it impossible to obtain good iron loss characteristics.

In addition, the final annealing atmosphere is set at 780°C when the secondary recrystallization annealing is completed.
It is preferable to use a temperature range of ~1000°C as a neutral atmosphere with respect to Sn and Co. If Sn or l'icu is oxidizing, the oxides of Sr+ and Cu may be damaged on the surface of the steel sheet. Grain boundary segregation of Sn in steel due to
This is not preferable because the magnetic properties deteriorate due to the quantitative change in the dispersed precipitation of CuxS, and the diglass film formation properties deteriorate due to the oxides of Sn and Cu, resulting in deterioration of the film properties. - If the final annealing atmosphere is reducing to Sn + Cu, normal gran growth of the surface layer occurs due to the decomposition of CuxS near the steel plate surface, so secondary recrystallized grains grow fully. , and the magnetic properties deteriorate.

In the present invention, the temperature increase rate in the final annealing is not particularly limited, and it may be maintained at a constant temperature within the range of 780 to 1000°C until secondary recrystallization is completed, or it may be maintained at a constant temperature within the range of 780 to 1000°C, or up to 1000°C. Although the temperature may be raised continuously at a rate that allows secondary recrystallization to be completed, it is preferable to maintain the temperature at a constant temperature or to raise the temperature slowly so that there is no difference in temperature distribution around the outer circumference of the coil. . As an atmosphere that is neutral to Sn and Cu, N2. An inert gas such as Ar is preferred, and some H2 gas may be mixed with the inert gas (depending on the amount of moisture drawn in from the annealing separator coating step).

Furthermore, in the annealing separator application step of the invention, Mg
We have discovered that by blending a specific substance into an annealing separator containing O as a main component, it is possible to produce a grain-oriented electrical steel sheet with high magnetic flux density that has even better core loss characteristics and glass film characteristics.

That is, W is added to the annealing separator whose main component is MgO.

Mo + Sr + Cu + Co + Nl *
Contains one or more selected from Sb or compounds containing these! Ff characteristic and ne 2nd
Inventive method.

Any of metal powder, alloy powder, oxide, sulfide, and sulfate may be used as the substance containing the above elements, but in the case of a substance that is poorly soluble in water, it is difficult to disperse it in the annealing separator slurry. From the viewpoint of reactivity during final annealing, it is preferable to use 325 mesh/4' mesh, preferably particles with a particle size equal to or finer than that of the annealing separator mainly composed of MgO, or particles in the form of a colloid.

(Example〕 Hereinafter, non-inventive embodiments will be described.

Example 1 C: 0.06% by weight, Sl: 3.
20%, Mn: 0080%, S: 0020≦
Acid-soluble Al: 0.025%, N: 0.0085%,
A silicon steel slab containing Sn: 0.09% and Cu: 0.11% was heated to 1300°C and then hot rolled to 2.0%.
It was made into a hot-rolled plate. This hot-rolled plate was soaked at 1120° C. for 4 minutes, pickled, and then cold-rolled to a thickness of 0.230. This cold-rolled plate was heated to 820°C for 3 minutes at a dew point of +50°C.
Decarburization was carried out in a mixed gas flow of 50% N + 50% H2.

MgO is the main component on both sides of the steel plate after decarburization annealing, [:B)
A slurry of an annealing molecular agent purified by K to 200 ppm in weight ratio to MgO was coated and dried, and one side contact F) 6f/rr
It was marked with / and wound into a coil. 20 of this
The temperature was raised at 1200°C/Hr in a mixed gas of N2+H, and then switched to H2 gas and soaked for 20 hours.

After cooling, unreacted annealing separator is removed by brush washing with water.
A coil sample was taken and heated at 800°C for 2 hours with N.
After strain relief annealing in No. 2, the magnetic properties were measured. The results are shown in Table 1.

Example 2 The same composition and hot rolling process as in Example 1 were carried out under the same conditions to produce a hot-rolled sheet with a thickness of 20 mm, and this hot-rolled sheet was subjected to precipitation annealing under the same conditions as in Example 1. .

Next, the plate was cold rolled to a thickness of 90.15 fl, and all steps after decarburization annealing were carried out under the same conditions as in Example 1.

The results are shown in Table 1.

Comparative Example 1 C: 0.06%, Sl:
3.20%+Mn: 0.080%, S: 0
．． 020%, acid 'i5'J dissolved Al: 0.025%, N:
A silicon steel slab containing 0.0085% was subjected to final annealing under the same conditions as in Example 1. The first magnetic property measurement results
Shown in the table.

Comparative Example 2 The same material as in Comparative Example 1 was used and the steps after hot rolling were performed under the same conditions as in Example 2. The results are shown in Table 1.

Comparative Example 3 The same material and decarburization annealing were performed under the same conditions as in Example 1.
Next, a slurry of an annealing separator mainly composed of MgO, which is conventionally used, is applied to both sides of the steel plate after decarburization annealing and dried to 6 f/rr? It was wound into a coil shape with an xf amount. As a result of analyzing the amount of CB) in the annealing separator, the weight ratio to MgO was 750 ppm. Next, this coil was subjected to finish annealing under the same conditions as in Example 1. The performance measurement results are shown in Table 1.

Table 1 Example 3 Weight: C: 0.07%, Sl: 3.26%
, Mn: 0085%, S: 0.023%, acid soluble A
l: 0.031%, N: 0.0090%, Sn: 0.1
0%, Cu: 0.08% silicon steel slab containing 130%
After heating to 0° C., it was hot-rolled to obtain a 1.7-inch hot-rolled sheet.

This hot-rolled plate was soaked at 1100° C. for 5 minutes, washed, and then cold-rolled to a thickness of 0.151 JE. This cold-rolled plate was heated at 800℃ for 4 minutes to 20% H2+ with a dew point of +40℃.
Decarburization was performed in a stream of 80% N2 mixed gas. After decarburization annealing, a slurry of an annealing separator containing MgO as the main component and CB) at a weight ratio of 1 OOppm VCn'JA to MgO was applied to both sides of the steel plate after decarburization annealing, dried, and applied to one side. It was made into an attached chrysanthemum and rolled up into a coil. This was heated to 800°C in N + 2% H2, which is neutral to Sn + Cu K, at a rate of 50°C/Hr, and then heated to 800°C x 30 Hr.
, N2 and 12$H2 to perform secondary recrystallization annealing. Next, the temperature was raised to 1206°C at 20°C/Hr in H2 gas and soaked for 20 hours.

After cooling, unreacted annealing separator is removed by brush washing with water.
Collect a coil sample and heat it at 800℃ for 2 hours with N2.
The magnetic properties were measured after strain-enhancing annealing. The results are shown in Table 2.

Example 4 The same material and annealing separation agent application step as in Example 3 were performed under the same conditions, and the product was wound into a coil. Next, this't-7
The temperature was raised to 80°C at 50°C/Hr in a mixed gas of N2 + 2% H2, and then heated to 900°C with moss at 3°C/Hr in N2 + 2% H2CP.
Secondary recrystallization by increasing Hr'T temperature? After completion, switch to H2 gas and incubate at 1200'C at 25°C/Hr''''C.
It was soaked at 1200°C for 20 hours. After cooling, the unreacted annealing separator was removed by brush washing with water, and a coil sample was taken and strain-removed annealed at 800° C. for 2 hours using N2 cows, and then the magnetic properties were measured. The results are shown in Table 2.

Table 2 Example 5 The same material and decarburization annealing process as in Example 3 were carried out under the same conditions, and the surface of the copper plate after decarburization annealing had a CB) content of 75p.
Annealing separation ill mainly composed of pmiC purified MgO
The substances shown in Table 3 were blended into the slurry, coated and dried to give an adhesion of ff 6 P/-, and wound into a coil. This coil was subjected to finish annealing according to the same instructions as in Example 3. After cooling, the unreacted annealing separator was removed by washing with water, and the coil and the sample were collected and subjected to strain relief annealing in N2 at 800° C. for 2 hours, and then the magnetic properties and film properties were measured. This result is the third
Shown in the table.

Table 3 *Adhesion: Absolutely resistant film (phosphate + chromic acid 4 g /
Minimum bending diameter without peeling after processing (baking at 800℃ x 70 seconds) Although it has been proposed, as in the present invention, by combining the molten steel composition in the steelmaking process, the plate thickness in the cold rolling process, and the composition of the annealing separator mainly composed of MgO in the annealing separator coating process, , high magnetic flux with excellent iron loss characteristics that were previously unobtainable! The fact that it has become possible to manufacture oppositely oriented electrical steel sheets is of great engineering significance, and furthermore, the above invention, the secondary recrystallization annealing temperature and atmosphere in the final annealing process, and the combination of specific substances in the annealing separator There is no technology that dramatically improves the p-magnetic properties by combining the two, and this is an extremely novel technology.

[Brief explanation of drawings]

Figure 1 shows high magnetic flux density directionality! A diagram showing the relationship between the plate thickness and magnetic properties of a magnetic copper plate. Figure 2 (1) is a diagram showing the change in Total N in steel due to the difference in plate thickness during the temperature rising process of finish annealing of a high magnetic flux density grain-oriented electrical steel plate. , Figure 2 (b) is a diagram showing the change in Na as ALH in steel due to the difference in plate thickness, and Figure 3 shows the relationship between the concentration of [B] in steel and the distance in the deep field direction with respect to the plate thickness. Figure 4 shows the MFCO in the annealing separator.
This is a diagram showing the relationship between the amount of [E] and the magnetic % property. °C) Spec 1 lube time (x fO' 5ee) Fig. 4

Claims (3)

[Claims] (1) C: 0.085% or less, Si: 2.0-4.0%
, Mn: 0.03-0.15%, S: 0.01-0.0
5%, acid-soluble Al: 0.01-0.05%, N: 0.0
05-0.010%, Sn: 0.03-0.5%, Cu
: A silicon steel material containing 0.02 to 0.3% is hot-rolled into a hot-rolled plate with an intermediate thickness, the hot-rolled plate is subjected to precipitation annealing, and then the final plate thickness is adjusted to 0.23 mm or less. In a series of manufacturing processes for high-magnetic flux density grain-oriented electrical steel sheets, which include a cold rolling process, a decarburization annealing process, an annealing separator coating process, and a final annealing process, the boron content is reduced in the annealing separator coating process. M purified to less than 400 ppm as boron
A method for producing a high magnetic flux density grain-oriented electrical steel sheet with excellent iron loss characteristics, characterized by using an annealing separator containing gO as a main component. (2) In the above final annealing process, secondary recrystallization is performed at 780°C.
2. The method according to claim 1, characterized in that the process is completed within a temperature range of ~1000[deg.] C. and in an atmosphere neutral to Sn and Cu. (3) W, Mo,
3. The method according to claim 1 or 2, characterized in that one or more selected from Br, Cu, Co, Ni, Sb, or compounds containing these are contained.