JPH02196403A - High magnetic flux density anisotropic silicon steel plate excellent in iron loss characteristic and manufacture thereof - Google Patents

Abstract

PURPOSE:To stabilize magnetic flux density of a high magnetic flux density anisotropic silicon steel plate whose thickness is equal to or less than 0.30mm, and reduce the secondary grain diameter, thereby effectively decreasing iron loss and realizing excellent characteristics of iron loss by a method wherein respectively specified amount of Si, Mn and Ge are contained, and the residual part is constituted of Fe and a very small amount of inevitable elements. CONSTITUTION:The following are contained in the tile plate; Si: 2.5wt.% or more and 4.0wt.% or less, Mn: 0.04wt.% or more and 0.15wt.% or less, and Ge: 0.005wt.% or more and 0.20wt.% or less. The residual part is constituted of Fe and a very small amount of inevitable elements. The plate thickness is 0.10-0.30mm. Basic component of steel row material is as follows; C: 0.02-0.90wt.%, Si: 2.5-4.0wt.%, Mn: 0.04-0.15wt.%, solAl: 0.010wt.%, and N: 0.0040-0.0120wt.%. As to silicon steel slab, Ge is added in the range of 0.005-0.20wt.% to the steel row material. The slab thus obtained is subjected to hot rolling and cold rolling. After intermediate annealing, the slab is rapidly cooled and subjected to a second cold rolling. After a final cold-rolled plate is finished, a first recrystallization annealing serving in combination as decarburization is performed, and further high temperature finish-annealing is performed, thereby manufacturing a silicon steel plate.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a high magnetic flux density grain-oriented silicon steel sheet with excellent iron loss characteristics and a method for manufacturing the same, in particular, by effective refining of the secondary grain size. , which aims to advantageously improve iron loss characteristics without causing a decrease in magnetic flux density.

(Prior art) Grain-oriented silicon steel sheets are soft magnetic materials that are used as core materials for transformers and generators. There is also a need to form surface coatings with fewer defects. Materials with excellent magnetic properties have crystal grains (hereinafter referred to as secondary grains) in the product with a Goss orientation (110) (001
) orientation is required, which improves the magnetic flux density.

As such crystal orientation control technology, for example, Japanese Patent Publication No. 33-4710 and Japanese Patent Publication No. 40-15644 contain AI in the material and reduce the final cold rolling reduction to 8.
A technology to achieve a high rolling reduction of 1 to 95% and to precipitate AIN during annealing before final cold rolling was also developed in Japanese Patent Publication No. 46-2382.
No. 0 discloses a technique in which the cooling rate during annealing before the final cold rolling is rapidly cooled from a temperature range of 750 to 950°C to 400'C in 2 to 200 seconds.

The above-mentioned techniques have improved the magnetic flux density, and now products having characteristics of about 96% of the theoretical value have been industrially manufactured. Along with this, iron loss has been improved, but there are two problems.

The first point is that as the magnetic flux density increases, the secondary particle size of the product increases, making it impossible to obtain the desired iron loss improvement effect.

The second point is that when the thickness of the product is made thinner in order to improve core loss, secondary recrystallization becomes difficult, and the orientation of the secondary grains cannot be aligned with the Goss orientation, which results in an increase in magnetic flux density. This leads to deterioration.

As a workaround for the first problem,
The publication discloses a technique for aging by maintaining the inter-pass temperature of cold rolling at a predetermined temperature, but even with this, it is difficult to completely control the grain size of the secondary grains, and furthermore, Not only is this extremely complicated in actual operation, but it is also powerless to deal with the second problem.

In addition, as a technique to avoid the second problem, there is
-197819, Cu is added to the material by 0.03 ~
0.5wtχ (hereinafter simply expressed as %) and Sn 0.03
Added ~0.5% and raised the finishing front temperature to 1150 in hot rolling.
~1250"C.

By controlling the finishing surface temperature to 950~1050℃ and the coiling temperature within the temperature range of 500~600'C, we can produce grain-oriented silicon steel sheets with a thickness of 0.30mm or less and a low core loss and high magnetic flux density. A manufacturing technique has been proposed. Adding Cu to a steel containing A1 has been known for a long time, as disclosed in the above-mentioned Japanese Patent Publication No. 33-4710, and the key point of this technology is to regulate the conditions of the hot rolling process. By this, the precipitation of AIN during hot rolling is suppressed, and at the same time, Sn is actively precipitated at the grain boundaries.

However, in the above technology, Sn is precipitated at the grain boundaries, which leads to embrittlement of the steel, which may cause breakage during subsequent rolling or cause surface defects with scale-like patterns, as well as poor pickling properties. Even after rolling, some oxidized layers remain on the surface of the steel sheet, causing decarburization failure during decarburization annealing, resulting in deterioration of magnetic properties.
Scratch-like defects may occur on the surface, resulting in lack of stability.

(Problems to be Solved by the Invention) The present invention advantageously solves the above problems by stabilizing the magnetic flux density in a high magnetic flux density grain-oriented silicon steel sheet with a plate thickness of 0.30 mm or less, and The purpose of the present invention is to propose a high magnetic flux density grain-oriented silicon steel sheet with excellent iron loss characteristics, which has fine secondary grain size and effectively reduces iron loss, together with an advantageous manufacturing method thereof.

(Means for Solving the Problems) As a result of extensive research to solve the above problems, the inventors have found that by incorporating Ge into steel, the secondary grain size after final annealing can be made finer. After discovering that it was possible to do this, and adding various ideas based on this knowledge, they were able to complete this invention.

That is, this invention provides St: 2.5% or more, 4.0
% or less, Mn: 0.04% or more and 0.15% or less, Ge: 0.005% or more and 0.20% or less, and sometimes further contains Mo: 0.005 to 0.2
0%, Cu: 0.01-0.3%, Sb: 0.00
5-0.2Q%, Sn: 0.010-0.025%
and P: Contains at least one selected from 0.010 to 0.10%, the remainder is Fe and trace amounts of unavoidable elements, and has a plate thickness of 0.10 to 0.30 mm, and has excellent iron loss characteristics. High magnetic flux density grain-oriented silicon steel plate.

In addition, this invention includes C: 0.02 to 0.090%, Si
:2.5 to 4.0%, Mn: 0.04
~0.15%, sol Al: 0.010~0.
050% and N: 0.0040-0.0120%
Hot-rolling a silicon steel slab with Ge added in the range of 0.005 to 0.20% to a steel material whose basic component is
Then, after performing the first cold rolling to obtain an intermediate thickness,
After intermediate annealing at 1000-1200°C for 0.5-10 min, it is rapidly cooled to at least 500°C at a cooling rate of 7°C or more, and then cold-rolled a second time under the condition of a rolling reduction of 75-90%. After finishing the final cold-rolled plate with a plate thickness of 0.10 to 0.30+nm, it is subjected to primary recrystallization annealing that also serves as decarburization, and then an annealing separator mainly composed of MgO is applied. This is a method for manufacturing a grain-oriented silicon steel sheet with high magnetic flux density and excellent iron loss characteristics, which comprises performing high-temperature finish annealing.

The experimental results that formed the basis of this invention will be explained below.

C: 0.066%, Si: 3.25%, S:
0.025%, sat Al: 0.025% and N: 0.008%, the remainder being substantially Fe.
Ge is not added to the molten steel having the composition of 0.001~
A total of 10 steel ingots were cast with various amounts added in the range of 0.50%.

After heating these steel ingots to 1200°C, they are bloomed and rolled.
Then, it was heated to 1420°C and hot rolled to a length of 2.3 m.
It was made into a hot-rolled plate with a thickness of m. After pickling these, they were subjected to the first cold rolling to obtain an intermediate plate thickness of 1.50 an, and then N
After annealing at 1100'C for 13 minutes in
It was rapidly cooled in a vortex at ℃ (average cooling rate: 40 ℃/S).

Then, after second cold rolling to a final thickness of 0.23 mm,
Decarburization annealing was performed at 850° C. for 15 minutes in wet H2. After that, after applying an annealing separator mainly composed of MgO,
Finish annealing was carried out at 1200° C. for 120 hours.

FIG. 1 shows the results of examining the magnetic properties and average secondary particle size of the product sheet thus obtained.

As is clear from the figure, Ge is present in the grain-oriented silicon steel material.
In the product plate containing 0.005% to 0.20%, the secondary particle size is small (resulting in a significant reduction in iron loss).Furthermore, there is no deterioration in magnetic flux density. .

When we investigated the cause of this reduction in secondary grain size, we found that the (110) strength of the texture of the surface layer of the decarburized and primary recrystallized plate of the experimental material was significantly lower, as shown in Figure 2. It was found that it was increasing. It was also found that among the AIN precipitation sizes of the decarburized and primary recrystallized plates, the frequency of precipitation of very small precipitates of 50 Å or less was increasing. This increase in the number of fine precipitates in AIN means that the suppressing force is strengthened, and therefore even if the thickness of the steel plate becomes thinner, a decrease in magnetic flux density can be prevented. it is conceivable that. Furthermore, an increase in (110) strength means an increase in the frequency of nucleation during secondary recrystallization, which is thought to result in an increase in the frequency of secondary grain generation and a reduction in the secondary grain size. .

Next, in order to investigate the cause of the increase in (110) intensity,
An investigation of the structure of the steel plate after intermediate annealing revealed that it was 0.032%.
As shown in the example in FIG. 3(a) in which Ge is added,
It was found that extremely fine carbides were densely precipitated. In comparison, the frequency of precipitation of fine carbides is much lower in the case shown in Fig. 3, in which Ge is not added.

From the above, the addition of Ge promotes the fine precipitation of carbides after intermediate annealing, increases the (110) strength of the steel sheet surface layer after decarburization and primary recrystallization annealing, and also nucleates secondary recrystallization. It is presumed that the secondary particle size became finer as a result of the increased generation frequency.

Now, the ingredients of the silicon steel sheet material used in this invention are as follows.

That is, C: 0.02-0.090%, St: 2
．． 5-4.0%, Mn: 0.04-0.15%, s
ol Al: 0.010-0.040% and N
: A steel material having a basic component of 0.0040 to 0.0120% contains Ge in a range of 0.005 to 0.20%. Furthermore, in order to reinforce the suppressing force, conventionally known S and/or Se: 0.01
0-0.040%, sb and/or Mo: 0.
005-0.20%, Cu: 0.01-0.3%,
P: 0.010-0.10%, and Sn: 0
．． At least one selected from 0.010 to 0.025% may be added.

The reason why the silicon steel material is limited to the above range in this invention will be explained below.

C is an element useful for improving the hot-rolled structure by utilizing transformation, and 0.02% or more is required for C.
If it exceeds 0%, decarburization failure will occur in the subsequent decarburization annealing process, which is not preferable.

Si is a major element that increases electrical resistance and reduces iron loss, and requires at least 2.5%, but 4.0%
If it exceeds this, cold rolling becomes difficult, which is not preferable.

sol Al and N are the basic elements of this component system, which precipitate as AIN in steel and act as inhibitors. is 0. ．． If the content exceeds the range of 0.0040% to 0.0120%, secondary recrystallization becomes unstable.

Mn not only effectively contributes to improving the hot workability of steel, but also when S or Se is mixed, MnS
Since it forms precipitates such as MnSe and MnSe and also functions as an inhibitor, the content is set in the range of 0.04 to 0.15%.

The greatest feature of this invention is the addition of Ge to the above ingredients. By adding Ge to the steel material, AIN and carbides in the steel become extremely finely dispersed and precipitated, which is even more preferable. This improves the primary recrystallization structure of thin steel sheets. However, when Ge is less than 0.005%, this effect is small;
If it exceeds 0%, the precipitation of carbides will decrease and the suppressive effect will be weakened, so it must be contained in a range of 0.005 to 0.20%.

The object of the present invention is achieved by using the above-mentioned steel material components, but the following elements can also be added to strengthen the restraining force.

In other words, S, Se, Sb,
Mo+Cu, P, Sn, etc. may be added.

Both S and Se are elements useful as inhibitors, and both have equivalent effects, but when the content is 0.010
If it is less than 0.0%, a sufficient suppressing effect cannot be expected;
If it exceeds 0.040%, it will cause coarsening of MnS etc., poor purification, deterioration of surface properties, etc. Therefore, it is preferable to add it in the range of 0.010 to 0.040%, either alone or in combination.

sb has the effect of increasing the suppressive force by segregating at the grain boundaries, and Mo has the effect of sharpening the nuclei of secondary grains in the Goss orientation. The effect is noticeable within the range.

Cu, like Mn, is an element that combines with S and Se to form precipitates and enhances the suppressing effect, and the effect is 0.01
It becomes noticeable in the range of ~0.3%.

Similar to sb, P has the effect of increasing the suppressing force by segregating at grain boundaries, and this effect is significant in the range of 0.010 to 0.10%.

Sn, like sb, is an element that segregates at grain boundaries and strengthens the suppressing force, but if it is less than 0.010%, the addition effect is poor, while if it exceeds 0.025%, it may deteriorate the magnetic properties and surface texture described above. Since it destabilizes, 0.010 to 0.025
%.

In addition, in each of the above components, C, S, Se, and N.

After AI, P, etc. have fulfilled their respective functions, C is mainly removed during decarburization annealing, and S, Se, N, AI, P, etc. are removed during purification annealing in the latter half of finish annealing, so they are removed in the base iron of the product. only a trace amount remains as an impurity.

Next, the manufacturing method of the present invention will be explained.

A silicon steel material having the above-mentioned components can be produced by any conventionally known melting method, agglomeration method, or blooming method. This silicon steel material is then rolled into a hot rolled coil by conventional hot rolling.

The hot-rolled coil is subjected to norm annealing as required as is known, and then further annealed at 1000 to 1200°C for 0.5
A final plate thickness of 0.10 to 0.30 mm is obtained by cold rolling twice with intermediate annealing of ~101 Ilin. The reason why the final plate thickness is limited to the range of 0.10 to 0.30M is that there is no need to apply the technique of this invention to plates with a thickness exceeding 0.30 mm, whereas 0.10+
This is because it is difficult to obtain a good product even with the technique of the present invention for those with a value less than +m+.

The first and second rolling reduction ratio distribution in the cold rolling process is described in, for example, Japanese Patent Publication No. 40-15644 and Japanese Patent Publication No. 46-238.
The technique disclosed in Publication No. 20 is sufficient. The second rolling reduction rate here requires a strong reduction as is known in the rolling of silicon steel containing AI, but in the composition system of this invention,
The preferred range is 75-90%, which is slightly lower than the conventional preferred range of 80-95%.

In the method of the invention, it is also advantageous to control the cooling rate during intermediate annealing. Regarding cooling during annealing of silicon steel containing Al, for example, Japanese Patent Publication No. 46-2
Rapid cooling is said to be better as described in Japanese Patent No. 3820. Since this is related to the precipitation of AIN during cooling and is extremely important in terms of magnetic properties, numerous experiments have been conducted and it has been pointed out that delicate control must be performed depending on the material components. Broadly speaking, there are 500 such technologies.
℃ (including blackening point) (Japanese Patent Publication No. 46-23820, Japanese Patent Application Laid-Open No. 5163314, Japanese Patent Application Laid-open No. 62-180015), and technology that requires controlled cooling to rapidly cool down to around ℃ (including the blackening point), and It is divided into techniques (Japanese Patent Publication No. 59-48934) that require controlled rapid cooling.

However, even in the former technology, the cooling rate below a temperature of around 500°C is considered to be unrelated to AIN precipitation, and the actual cooling process involves methods such as hot water cooling or water quenching, and in practice The difference between the two was not clear.

As a result of intensive research into this point, the inventors found that for materials containing A1 and Ge:
It is advantageous to perform rapid cooling at a rate of 7°C/s or more, and more preferably, the temperature range that substantially requires rapid cooling is from 750°C to 250°C, and this range is within the average cooling rate near ~25°C/s, and even more preferably, the temperature range from 750 to 250"C is as described above with an average cooling rate of ~25°C/s; 250°C to 150°C It has been found that it is preferable to slow the cooling rate to 4° C./s or less.

Here, the average cooling rate in the range of 750℃ to 250℃ is 7
If it is less than 25° C./s, coarse precipitation of AIN tends to occur, while if it exceeds 25° C./s, the amount of ^IN precipitated may be insufficient. Therefore, the preferred average cooling rate in this temperature range is 7°C/s to 25°C/s, but this is because the average cooling rate is smaller than that of materials that do not contain Ge. It is also advantageous for industrial production.

Also, the average cooling rate from 250℃ to 150''C is particularly important, and if this is large, the reason is unknown, but 2
The secondary grains may become coarse locally and the iron loss may deteriorate.

Therefore, it is particularly advantageous for the average cooling rate in this temperature range to be 4° C./s or less.

In addition, in this invention, in the cold rolling process,
The technique of applying aging treatment between multiple passes as disclosed in Japanese Patent Publication No. 3846 and Japanese Patent Publication No. 54-29182 is not particularly necessary, but since it has a slight stabilizing effect on magnetic properties, it does not hinder its application. do not have.

The cold-rolled plate rolled to the final thickness is then rolled to 750 mm according to the conventional method.
Decarburization annealing is performed at ~900°C for about 10.5 to 10 minutes. At this time, for those in which the above-described cooling control was performed during the intermediate annealing, an effect of improving the magnetic properties of the - layer can be expected by rapidly heating at a temperature increase rate of 10° C./s or more.

An annealing separator containing MgO as a main component is applied to the surface of the steel sheet after decarburization annealing to prevent seizure of the steel sheet during final annealing and to form a forsterite film on the surface.

Here, as the annealing separator mentioned above, Japanese Patent Publication No. 51-124
It is more preferable to add TiO□ as disclosed in Japanese Patent No. 51.

Finish annealing is performed using N2 or N2*N at 1100℃ or higher.
! It is applied for more than 5 hours in a mixed gas atmosphere such as +Ar,
During secondary recrystallization, it is particularly desirable to use a mixed gas atmosphere of N2 and Nt.

Furthermore, a known inorganic coating mainly composed of magnesium phosphate, aluminum phosphate, calcium phosphate, etc., which serves both as insulation and imparts tension, is applied to the surface of the steel sheet after finish annealing, which also serves as flattening annealing. You can also do it.

(Effect) The crystal grain size of the product obtained is 2 times smaller than that of conventional products.
It is characterized by its extremely small secondary particle size. That is, while the conventional average secondary particle diameter was about 10-20111 Im, the average secondary particle diameter of the present invention was only 3-7 mm. Moreover, since there is no decrease in crystal orientation, an excellent grain-oriented silicon steel sheet with high magnetic flux density and extremely low core loss can be obtained. Furthermore, it has the advantage of excellent stability in surface properties and magnetic properties, and is easy to manufacture.

(Example) Example 1 C: 0.062%, St: 3.26%, Mn:
0.075%, Se: 0.010%, S: 0
．． 015%, sol Al: 0.025%, N:
0.008%, Sb: 0.020% and Ge
A slab containing 0.045% Fe with the remainder being substantially Fe was heated at 1380° C. for 3 hours and then hot rolled into a hot rolled sheet with a 2.2 pitch thickness. This hot-rolled sheet was then annealed in Nt at 1150° C. for 30 seconds, pickled, and cold-rolled for the first time to obtain a cold-rolled sheet having an intermediate thickness of 1.40 mm.

Next, this cold-rolled sheet was divided into six parts and heated at 1050℃22 in N2.
Intermediate annealing was performed for 1 minute, but at this time the temperature was increased from 750℃ to 250℃.
Mist cooling, gas cooling, and hot water cooling methods were used to adjust the average cooling rate to 150°C and the average cooling rate from 250°C to 150°C as shown in Table 1. An example of the cooling curve at this time is shown in FIG.

These steel plates were cold-rolled for the second time to a thickness of 0.20 an (rolling reduction: approximately 86%), and then decarburized annealed at 850°C for 12 minutes in wet H2. Then, after applying a separating agent mainly composed of MgO,
The temperature was raised from 850°C to 1150″C at a heating rate of 7°C/h in an atmosphere of
After increasing the temperature to 0°C at a rate of 15°C/h, the temperature was maintained at 1200°C for 10 hours, and after cooling to 700°C, the atmosphere was switched to N2 for cooling. Thereafter, the unreacted separating agent was removed and the tension coating was baked into a product.

Table 1 also shows the results of investigating the magnetic properties of the product thus obtained.

As is clear from the table, although good magnetic properties were obtained regardless of the cooling conditions,
The average cooling rate to 0℃ is 7 to 25℃ and 250℃
Particularly good values are obtained when the average cooling rate from °C to i:'c is 4'C/s or less.

ing.

Example 2 C: 0.055%, St: 3.20%, Mn:
0.080%, Se: 0.024%, Cu:
0.03%, sol At: 0.018%, N:
0.0082%, Mo: 0.012% and Ge
A slab containing 0.040% Fe with the remainder being substantially Fe was heated to 1420°C and subsequently hot rolled to form a 2.5-thick hot-rolled plate. After pickling this hot-rolled sheet, it was cold-rolled for the first time to give an intermediate thickness of 1.20 am, then heated in N2 at 1000°C for 12 minutes, and then cooled with mist to form the curve shown in Figure 4. After performing the cooling treatment of C, a final plate thickness of 0.18 mm+ was obtained by a second cold rolling. At this time, aging treatment was performed at 300° C. for 1 minute after each rolling pass.

The cold-rolled plate was then divided into six parts, each of which was heated at 84°C in wet hydrogen.
Decarburization annealing was carried out for 12 minutes at 0°C.
The temperature increase rate from 'C to 800C was changed as shown in f~ in Table 2.

After that, a separating agent mainly composed of MgO is applied, and then (N
After raising the temperature to 1150°C at a heating rate of 9°C/h in an atmosphere of
The mixture was cooled to 0''C, and then switched to N2 for further cooling. After that, unreacted separation agent was removed and the tension coating was baked to obtain a product.

Table 2 also shows the results of investigating the magnetic properties of the product board thus obtained.

Table 2 As is clear from the table, particularly good magnetic properties were obtained when the temperature increase rate during decarburization and primary recrystallization annealing was rapid heating of 10° C./s or more.

Example 3 Silicon steel material slabs having various compositions shown in Table 3 were
, B at 1250°C for 2 hours, others (C-1)
After heating at 1400″C for 1 hour,
A hot rolled sheet with a thickness of 2.5 mm was obtained by hot rolling.

After pickling these hot-rolled sheets, the first cold rolling yielded 1.35
+m++ intermediate plate thickness, and then annealed at 1100°C for 2 minutes, then placed in hot water at 80°C and cooled along the cooling curve shown in FIG. 4(a). Next, after a second cold rolling to a final plate thickness of 0.23 mm, decarburization annealing was performed at 860°C for 13 minutes in wet H2, and a separating agent mainly composed of MgO was applied, followed by 800°C. The temperature was raised in an atmosphere of 82°C to 1200°C at a heating rate of 5°C/h from 800°C.
The temperature was raised in an atmosphere of (NZ: 20%-L, 80%), then the atmosphere was switched to N2 at 1200"C, held at 1200°C for 5 hours, cooled to 600°C, and further N2 gas After switching to the temperature, it was cooled to room temperature.

Thereafter, the unreacted separating agent was removed and the tension coating was baked into the product.

Table 4 shows the results of investigating the magnetic properties and surface defect rate of the product board thus obtained.

Furthermore, Table 5 shows the analysis results of the components in the steel of the obtained product. In addition to the listed components, trace amounts of C, AI, S, Se, N, etc. were present as impurity components in the iron, but these had been reduced to a level that caused no magnetic problems.

1. As is clear from the same table, good magnetic properties are obtained only when an appropriate amount of Ge is contained according to the present invention.

(Effects of the Invention) Thus, according to the present invention, it is possible to stably obtain grain-oriented silicon steel sheets with excellent magnetic properties, particularly magnetic flux density and iron loss properties, even for thin plates with a thickness of 0.30 am or less, which is advantageous. It is.

[Brief explanation of the drawing]

Figure 1 shows the Ge content and BII+ Wlff/! i. Figure 2 shows the relationship between the Ge content and the (110) strength of the surface texture of the decarburized/primary recrystallized plate and the frequency of precipitation of fine AIN. Figure 3 is a transmission electron micrograph (X 100000
) Figure 4 shows examples of cooling curves after intermediate annealing, including water cooling at 80°C (a), mist cooling (C), (('), gas cooling (
e). Figure 2 Figure 3 Figure 4, a) (b) Large fllll FJ'r I/l / S jθ, IpM

Claims (1)

[Claims] 1. Si: 2.5 wt% or more, 4.0 wt% or less, M
n: 0.04 wt% or more, 0.15 wt% or less, Ge:
Contains 0.005wt% or more and 0.20wt% or less,
The remainder consists of Fe and trace amounts of unavoidable elements, and the plate thickness is 0.
．． A high magnetic flux density grain-oriented silicon steel sheet with excellent iron loss characteristics of 10 to 0.30 mm. 2. Si: 2.5wt% or more, 4.0wt% or less, Mn
: 0.04 wt% or more, 0.15 wt% or less, Ge: 0
．． 0.005 wt% or more and 0.20 wt% or less,
and Mo: 0.005 to 0.20 wt%, Cu: 0.01 to 0.3 wt%, Sb: 0.005 to 0.20 wt%, Sn: 0.010 to 0.025 wt%, and P: 0.0
Contains at least one type selected from 10 to 0.10 wt%, and the remainder is Fe.
and trace amounts of unavoidable elements, and the plate thickness is 0.10 to 0.
．． High magnetic flux density grain-oriented silicon steel sheet with excellent core loss characteristics of 30. 3. C: 0.02-0.090 wt%, Si: 2.5-4.0 wt%, Mn: 0.04-0.15 wt%, sol Al: 0.010-0.050 wt% and N
: A silicon steel slab in which Ge is added in the range of 0.005 to 0.20 wt% to a steel material whose basic component is 0.0040 to 0.0120 wt% is hot rolled, and then the first cold rolling is performed. After rolling to obtain an intermediate plate thickness, 1000-1200℃,
At least 500℃ after 0.5-10min intermediate annealing
A final cold-rolled plate with a thickness of 0.10-0.30 mm is obtained by rapidly cooling the plate at a cooling rate of 7°C/s or higher, and then performing a second cold rolling at a rolling reduction of 75-90%. After finishing to M
A method for producing a high magnetic flux density grain-oriented silicon steel sheet with excellent iron loss characteristics, which comprises applying an annealing separator containing gO as a main component and then performing high-temperature finish annealing. 4. The cooling rate after intermediate annealing is set at an average cooling rate of 7 to 25°C/s over the temperature range from 750°C to 250°C.
The manufacturing method according to claim 3, wherein: 5. The cooling rate after intermediate annealing is 7 to 25°C/s from 750°C to 250°C, and 15°C from 250°C.
Claim 3: The average cooling rate is 4°C/s or less until 0°C.
Manufacturing method described.