JPH10310822A - Production of grain-oriented silicon steel sheet stable in magnetic property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the dispersion of the material in the operation of steel making and hot rolling stages and to obtain a grain-oriented silicon steel sheet having stable magnetic properties by estimating the primary factor of the dispersion of the material caused by disturbance in the operation before decarburizing annealing, swiftly changing the annealing pattern in decarburizing annealing for a silicon steel slab having a specified compsn. based on a material model and executing treatment at a specified heating rate. SOLUTION: A silicon steel slab contg., by weight, 0.8 to 4.8% Si, <=0.085% C, 0.01 to 0.065% acid soluble Al, <=0.012% N, and the balance Fe is heated at <=1280 deg.C, is subjected to hot rolling and is subsequently subjected to cold rolling for one time or >=two times including annealing to regulate its sheet thickness into the final one, which is subjected to decarburizing annealing and is thereafter subjected to finish annealing to obtain a grain-oriented silicon steel sheet, where, in the decarburizing annealing stage, it is heated at the average heating rate of 10 to 40 deg.C/sec at least to 650 deg.C and is then heated at a heating rate of >=60 deg.C/sec to a temp. calculated based on a material prediction model to regulate the average grain size in the primary recrystallized structure, and after that, nitriding treatment is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a so-called grain-oriented electrical steel sheet in which crystal grains are accumulated in a {110} <001> direction with a Miller index, and to control the decarburization annealing pattern based on a material prediction model. Adjust the primary recrystallized grain structure by
It discloses a manufacturing method for producing stable magnetic characteristics.

[0002]

2. Description of the Related Art Grain-oriented electrical steel sheets are {110} <001.
> 0.8% of Si composed of crystal grains accumulated in the orientation
It is a steel sheet containing 〜4.8%. This steel sheet is required to have excitation characteristics and iron loss characteristics as magnetic characteristics. As an index indicating the excitation characteristic, a magnetic flux density: B _{8 at a} magnetic field strength of 800 A / m is usually used. As an index indicating iron loss characteristics, iron loss per kg of steel sheet when magnetized at a frequency of 50 Hz to 1.7 T: W _17/50 is used. The magnetic flux density: B ₈ is the largest controlling factor of the iron loss characteristics, and the higher the magnetic flux density: B ₈ value, the better the iron loss characteristics. Flux density: in order to increase the B ₈ is important to align advanced crystal orientation. The control of the crystal orientation is achieved by utilizing a catastrophic grain growth phenomenon called secondary recrystallization.

In order to control the secondary recrystallization, it is necessary to adjust the primary recrystallization structure and fine precipitates called inhibitors.

[0004] The inhibitor has a function of suppressing the growth of general grains in the primary recrystallized structure and preferentially growing only grains of a specific orientation. MFLittmann is a typical example of an industrially used inhibitor.
(Japanese Patent Publication No. 30-3651), JEMay & D. Turnbu
Met. Soc. AIME212 (1958) p769, MnS disclosed by Taguchi et al. (JP-B-40-15644), AlN disclosed by Taguchi et al.
No. 13469) discloses MnSe.
In order to finely precipitate these precipitates, a method has been adopted in which the precipitates are completely dissolved in slab heating before hot rolling, and then fine conditions are formed by controlling the conditions of hot rolling and subsequent annealing.

[0005] In order to completely dissolve these precipitates, it is necessary to heat at a high temperature of 1400 ° C or more, which is about 200 ° C higher than the slab heating temperature of ordinary steel, and has the following problems. (1) A dedicated heating furnace is required. (2) The energy intensity of the heating furnace is high. (3) There is a large amount of molten scale, and operation management such as so-called sticking out is necessary.

[0006] As a manufacturing method by low-temperature slab heating to solve this problem, Komatsu et al. (Japanese Patent Publication No. Sho 62-45285) formed a nitride (Al,
A method using Si) N as an inhibitor is disclosed.

On the other hand, there is almost no knowledge about the adjustment of the primary recrystallized grain structure.
No. 2,866 discloses its importance. In particular, in the production method by Komatsu et al. (Japanese Patent Publication No. 62-45285) using low-temperature slab heating, the primary recrystallization structure can be largely adjusted by the primary recrystallization annealing conditions.

The production of grain-oriented electrical steel sheets is carried out under strict control standards because various factors in each step fluctuate the inhibitor and primary recrystallization structure and affect the secondary recrystallization behavior. I have. However, it is difficult to eliminate operational disturbances. Processes that are particularly problematic in terms of production stability are the inhibitor-based component adjustment in the steelmaking process and the hot rolling process. For example, uneven heating of the skid at the time of slab heating, rolling caused by zooming of the passing speed of the finish hot rolling, changes in cooling conditions, and variations in the finishing temperature and the winding temperature can be mentioned. These disturbances change the structure of the hot-rolled sheet and the state of precipitates, and cause variations in the magnetic properties of the final product.

[0009]

SUMMARY OF THE INVENTION The present invention is intended to solve such a problem, and predicts in advance factors of material variation caused by operational disturbances before decarburizing annealing, and calculates a material model. An object of the present invention is to provide a method for producing a grain-oriented electrical steel sheet having uniform magnetic properties by quickly changing an annealing pattern of decarburizing annealing to adjust a primary recrystallization structure.

[0010]

SUMMARY OF THE INVENTION The present invention is as follows.

(1) Si: 0.8 to 4.8% by weight
%, C: 0.085% or less, acid-soluble Al: 0.01
６５0.065%, N: 0.012% or less, and 12% of a silicon steel slab composed of the balance of Fe and unavoidable impurities.
After being heated at a temperature of 80 ° C. or less and hot-rolled, the final thickness is obtained by one or two or more cold-rollings including annealing, in a method for producing a grain-oriented electrical steel sheet to be subjected to decarburizing annealing and finish annealing. Heat at an average heating rate of 10 to 40 ° C / sec until at least 650 ° C in the decarburizing annealing process,
Directional electromagnetic with stable magnetic characteristics characterized by heating at a heating rate of / sec or more to the temperature calculated based on the material prediction model, adjusting the average grain size of the primary recrystallization structure, and then performing nitriding treatment Steel plate manufacturing method.

(2) Si: 0.8 to 4.8% by weight
%, C: 0.085% or less, acid-soluble Al: 0.01
６５0.065%, N: 0.012% or less, and 12% of a silicon steel slab composed of the balance of Fe and unavoidable impurities.
After heating at a temperature of 80 ° C. or less and hot rolling, the final thickness by cold rolling once or more than two times including annealing, decarburizing annealing, in the method of manufacturing a grain-oriented electrical steel sheet to perform finish annealing, In the latter half of the decarburization annealing process, the heating is performed at a heating rate of 60 ° C./sec or more to the temperature calculated based on the material prediction model to adjust the average grain size of the primary recrystallization structure, and thereafter, the nitriding treatment is performed. For producing grain-oriented electrical steel sheets with stable magnetic properties.

The present inventors decarburized annealed a cold-rolled sheet in which the inhibitor component, the crystal structure of the hot-rolled sheet and the state of the precipitate were known, and examined the relationship between the annealing conditions and the grain structure. It has been found that there is a certain relationship between the grain structures and that by predicting this, excellent magnetic properties can be stably obtained.

FIG. 1 conceptually shows a material model for predicting a temporary recrystallization structure of an annealed plate. That is, based on the components of the hot-rolled sheet, the heat history and the rolling history, and the heat history of the hot-rolled sheet annealing, the ferrite grain size and precipitate (Al
N) is calculated to predict the structure before cold rolling, and from the obtained ferrite grain size and precipitate state, and the heat history and rolling history of the cold rolled sheet, the average grain size after the target temporary recrystallization is obtained. The temporary recrystallization heat history (decarburization annealing temperature) is determined, the grain structure of the temporary recrystallization is adjusted based on the obtained conditions, nitriding treatment is performed, an inhibitor is formed, and the finish annealing is performed. It was confirmed that recrystallization was stable and magnetic properties became uniform.

However, in the conventional decarburization annealing equipment, heating mainly by a radiant tube or an elema using radiant heat is mainly used, so that an annealing cycle cannot be changed in a short time in accordance with disturbance in a preceding process. Therefore, we studied the stabilization of the magnetic properties of the product by adjusting the primary recrystallization structure by changing the annealing pattern using dielectric heating, energization heating, etc., which can change the heating temperature in a short time. .

Performing decarburizing annealing of grain-oriented electrical steel sheets by rapid heating is disclosed, for example, in Japanese Patent Laid-Open No. 1-290716. However, an object of the disclosed invention is to improve the iron loss yield by making the secondary recrystallized structure finer by performing rapid heating at a heating rate of 100 ° C./sec or more from room temperature to a temperature range of 675 ° C. or more. It is. When rapid heating is performed by such a method, the primary recrystallization texture fluctuates greatly. Therefore, even if the primary recrystallization grain size is fixed, the magnetic characteristics cannot be controlled to be constant, and the magnetic characteristics in the longitudinal direction and the like are made uniform. Turned out to be ineffective. Therefore, when the conventional rapid heating technique is simply applied to change the annealing pattern, the magnetic characteristics cannot be stabilized.

The present inventors have conducted studies on the annealing pattern, and by appropriately selecting the temperature at which rapid heating is started, the primary recrystallization without affecting the primary recrystallization texture even when rapid heating annealing is employed. It was confirmed that only organizational adjustment could be performed.

In the following, an inhibitor component (acid-soluble A
A description will be given based on the results of an experiment performed on l). S by weight
i: 3.2%, C: 0.05%, acid-soluble Al: (1)
0.024, and (2) 0.029%, N: 0.08%
Is heated at a temperature of 1150 ° C.
It was hot rolled to a thickness of 2.3 mm. Thereafter, it is annealed at 1120 ° C. and cold-rolled to a thickness of 0.23 mm.
Decarburization annealing was performed in a temperature range of ° C., and annealing was performed in an atmosphere containing ammonia to reduce nitrogen to 0.02%. Then, after applying an annealing separator mainly containing MgO, finish annealing was performed. Table 1 shows the primary recrystallized structure (average particle size) after decarburizing annealing and the magnetic properties (B ₈ ) of the product.

[0019]

[Table 1]

From Table 1, it can be seen that the steel sheet 1 (acid-soluble Al: 0.0
24%) and steel sheet 2 (acid-soluble Al: 0.029%)
When decarburizing annealing is performed at the same annealing temperature, the magnetic flux density (B
It can be seen that there is a difference in ₈ ). On the other hand, when the primary recrystallization average particle diameter after decarburization annealing is the same, the magnetic properties of the product are at the same level despite the difference in the content of acid-soluble Al.

Therefore, in the production of a grain-oriented electrical steel sheet, even if there is a variation in the material in the longitudinal direction of the steel sheet such as the steel sheets 1 and 2 due to operational disturbance before the decarburization annealing, the primary steel sheet does not If the recrystallized average particle size is made substantially uniform, the magnetic properties of the product can be made uniform.

For example, in order to manufacture a product having a magnetic flux density (B ₈ ) of about 1.93 T from the steel sheets 1 and 2, the average primary recrystallization particle size may be adjusted to about 25 μm. In order to set the average primary recrystallization grain size of both steel sheets to about 25 μm, it is necessary to change the annealing temperature to 870 ° C. for steel sheet 1 and 850 ° C. for steel sheet 2.

Therefore, the radiant heating method (10
° C / sec) and electric heating (60, 300 ° C / sec) are combined, and the steel sheet is heated by radiant heating until heating is in progress, then the steel sheet is heated by electric current heating. The steel sheet 2 was subjected to decarburizing annealing at 850 ° C. Thereafter, annealing was performed in an ammonia-containing atmosphere to reduce nitrogen to 0.02%. Then after coating an annealing separator mainly comprised of MgO, perform finish annealing, the magnetic flux density was measured B ₈ of the resulting product.

FIG. 2A shows the correlation between the magnetic flux density B ₈ (T) of the product obtained from the steel sheet 1 and the rapid heating start temperature Tr (° C.), and FIG. The correlation between the magnetic flux density B ₈ (T) of the product and the rapid heating start temperature Tr (° C.) is shown. Here, the rapid heating start temperature Tr is
The temperature at which the steel sheet starts to be heated by electric heating. FIG.
As is clear from any of the steel sheets, when the heating start temperature by the rapid heating device is lower than 650 ° C., the magnetic flux density (B ₈ ) greatly changes depending on the heating speed, but the rapid heating start temperature is 650 ° C. or higher. Then, it can be seen that the magnetic characteristics (B ₈ ) after the secondary recrystallization are stabilized according to the primary recrystallization particle size. Since the average primary recrystallized grain size after annealing is in the range of 24.5 to 26 μm in any of the annealing cycles, the magnetic flux density (B ₈ ) greatly changes depending on the heating rate when the rapid heating start temperature is lower than 650 ° C. This is probably due to the texture.

As described above, when continuously manufacturing a grain-oriented electrical steel sheet having the above-described variations in the materials,
Even if the particle size is adjusted by rapid heating from room temperature as in the past, the magnetic properties are not stabilized.However, by appropriately selecting the temperature at which rapid heating is started, the primary recrystallization can be performed without affecting the primary recrystallization texture. It is possible to adjust the grain size of the crystal structure. By using such a heating method, by changing the soaking temperature at each portion in the longitudinal direction of the steel sheet to make the grain size of the primary recrystallization structure uniform, it is possible to manufacture a product having stable magnetic properties in the longitudinal direction of the steel sheet. .

In the present invention, the soaking temperature is changed at each part in the longitudinal direction of the steel sheet. The soaking temperature is determined by a material model that predicts the primary recrystallization structure of the annealed sheet.

FIG. 1 is a schematic view showing a material model according to the present invention. More specifically, for example, the ferrite grain size (D ₀ ) before cold rolling, the amount of precipitate (I ₀ ), Average particle size (r ₀ ), heat history of cold rolling {for example, temperature (T _c ), stay time (t _c ), reduction history [number of passes (N _p ), reduction ratio (R), etc.]], decarburization annealing The relation between the metallographically important factors such as history [heating rate (dT), soaking temperature (T _s ), soaking time (t _s )] and the primary recrystallized grain size (D) is described by the theory. Through experiments, a regression equation, that is, D = f ｛D ₀ , I ₀ , r ₀ , T _c , t _c , N _p , R, d
T, T _s , t _s ... May be obtained in advance and used as a material prediction model.
For example, to obtain a decarburizing annealing temperature (soaking temperature: T _s ) for obtaining a desired crystal grain size D from such a regression equation,
A value other than T _s may be input to calculate T _s .

In addition, the present inventors can use a rapid heating device in the second half of the decarburization annealing to heat the material to a temperature based on the material model, without affecting the primary recrystallization texture. It was also confirmed that only the particle size adjustment of the tissue was possible.

The steel sheet 2 was subjected to decarburization annealing at a soaking temperature of 850 ° C. based on the above-mentioned steel sheet. Then, as for the steel sheet 1, some of the samples were decarburized and annealed at a temperature of 850 ° C., and then heated by heating (60, 300 ° C./sec).
The particle size was adjusted by heating to 0 to 920 ° C. and performing additional annealing for a short time. Further, for a part of the sample of the steel sheet 1, the particle size was adjusted by rapidly heating from room temperature to 870 ° C. by electric heating (60, 300 ° C./sec). Thereafter, annealing was performed in an ammonia-containing atmosphere to reduce nitrogen to 0.02%. Then M
After applying an annealing separator containing gO as a main component, finish annealing was performed.

[0030]

[Table 2]

As is clear from Table 2, the heating rate was 60 ° C.
magnetic flux density (B ₈ ): about 1.93 T by annealing at a heating temperature of 870 to 910 ° C. at any heating rate of 300 ° C./sec and 300 ° C./sec to adjust the average primary recrystallization particle size to about 25 μm. It can be seen that the product can be manufactured. On the other hand, the samples subjected to rapid heating by the rapid heating device from the beginning of the decarburization annealing have significantly different magnetic properties of the products even though the average primary recrystallization grain size is almost the same. This is considered to be due to the fact that when the low temperature region of the decarburizing annealing is rapidly heated, the texture changes greatly.

As described above, after annealing by the conventional decarburizing annealing equipment, the particle size is adjusted by the rapid heating equipment according to the material prediction model, thereby stabilizing the magnetic properties (B ₈ ) after the secondary recrystallization. Products can be manufactured. Therefore, when continuously manufacturing non-oriented electrical steel sheets, products with the same level of magnetic properties can be stably manufactured by performing additional annealing by means of a rapid heating device and adjusting the grain size based on a material prediction model. it can.

[0033]

Next, an embodiment of the present invention will be described. In the present invention, Si: 0.8 to 4.8%, C:
0.085% or less, acid-soluble Al: 0.01 to 0.06
5%, N: 0.012% or less is required.

When Si is added in a large amount, the electric resistance increases and the iron loss characteristics are improved. However, 4.8%
If it exceeds, it will be easy to crack during rolling. Also,
If it is less than 0.8%, γ transformation occurs during finish annealing, and the crystal orientation is impaired.

C is an effective element for controlling the primary recrystallization structure, but has an adverse effect on the magnetic properties, so that it is necessary to remove carbon before the finish annealing. If C is more than 0.085%, the decarburization annealing time will be long and productivity will be impaired.

Acid-soluble Al is an essential element for bonding to N in the present invention to function as (Al, Si) N as an inhibitor. The limited range is 0.01 to 0.065% at which the secondary recrystallization is stabilized. If N exceeds 0.012%, voids in the steel plate called blisters are generated.

In addition, S has an adverse effect on the magnetic characteristics.
It is desirably 015% or less. Sn improves the texture after decarburizing annealing and stabilizes secondary recrystallization. 0.0
It is desirable to add 2 to 0.15%. Cr is an element that improves the oxide layer in decarburizing annealing and is effective for forming a glass film. It is desirable to add 0.03 to 0.2%. In addition, the inclusion of trace amounts of Cu, Sb, Mo, Bi, Ti, etc. in steel does not impair the gist of the present patent.

The above-mentioned silicon steel slab is obtained by melting the steel in a converter or an electric furnace or the like, subjecting the molten steel to vacuum degassing if necessary, and then subjecting the steel to continuous casting or ingot making followed by slab rolling. Thereafter, slab heating is performed prior to hot rolling. In the present invention, the slab heating temperature is set to 1280 ° C. or less to avoid various problems of high-temperature slab heating.

The steel sheet obtained by the hot rolling described above is optionally subjected to a short annealing at 900 to 1200 ° C. for 30 seconds to 30 minutes, and then cold rolled once or twice or more with the annealing interposed therebetween. To the final thickness. By performing this annealing, the structure of the hot-rolled sheet can be adjusted by recrystallization and precipitates can be adjusted, so that the magnetic properties of the product generally improve. For the cold rolling, it is necessary to make the final cold rolling reduction 80% or more in order to adjust the primary recrystallization texture as shown in Japanese Patent Publication No. 40-15644.

The steel sheet after cold rolling is subjected to decarburizing annealing in a humid atmosphere in order to remove C contained in the steel. In this decarburizing annealing step, heating is performed at an average heating rate of 10 to 40 ° C./sec up to at least 650 ° C., and subsequently, heating is performed at a heating rate of 60 ° C./sec or more to the annealing temperature calculated based on the material prediction model. Adjust the average particle size of the recrystallized structure.

The start temperature of the rapid heating is limited to 650 ° C. or more because when the heating is performed from a temperature lower than this temperature, the primary recrystallization texture is greatly changed and the magnetic characteristics are changed. The reason why the average heating rate before the rapid heating is set to 10 to 40 ° C./sec is that the lower limit is too long at less than 10 ° C./sec rather than a material problem, and the furnace length becomes longer. This is because the cost increases. On the other hand, if the upper limit is higher than 40 ° C./sec, the texture changes greatly, and the magnetic properties cannot be arranged only by the grain structure.

In the decarburizing annealing step, the temperature is calculated at 60 ° C./s up to the temperature calculated based on the material prediction model in the latter half of the decarburizing annealing.
The average particle size of the primary recrystallized structure may be adjusted by rapid heating at a heating rate of ec or more.

The method of rapid heating is not particularly limited, and includes a method using a high-energy heat source such as laser and plasma, a method using induction heating, an electric heating device, and the like.

After adjusting the primary recrystallization structure under the above conditions,
The inhibitor ((Al, Si) N) is adjusted by nitriding. Examples of the nitriding treatment include a method of annealing in an atmosphere containing a gas having a nitriding ability such as ammonia, and a method of adding a powder having a nitriding ability such as MnN to an annealing separator and performing the finishing annealing. In order to stably perform the secondary recrystallization, the amount of nitrogen after the nitriding treatment is such that the weight ratio of N / Al to the amount of Al in the steel is 0.5 or more, preferably 0.1% or more.
It is necessary to be 67 or more. After that, finish annealing is performed, and {110} <001> oriented grains are preferentially grown by secondary recrystallization.

[0045]

【Example】

[Example 1] Si: 3.2%, C: 0.05%, acid-soluble Al: 0.03%, N: 0.007%, Mn: 0.1
%, S: 0.007%, Cr: 0.1%, Sn: 0.0
A 5% silicon steel slab was heated to 1150 ° C. and hot rolled to a thickness of 2.3 mm. Based on the difference in heating temperature history due to the skid when heating the slab in the longitudinal direction of this material,
First, the precipitate grain size (such as AlN) and the ferrite grain size of each part of the hot rolled sheet were calculated. Next, the temperature history at the time of cold rolling was input together with these data, and the primary recrystallization annealing temperature at which the average primary recrystallization particle size became constant (22 μm) was calculated. The longitudinal recrystallization temperature was 860 ° C. to 880 ° C. When the annealing temperature in the direction is changed, the magnetic flux density (B ₈ ) becomes 1.9.
It was found that a 0T product could be manufactured stably. Then, after decarburizing annealing was performed by changing the annealing pattern in the longitudinal direction based on this material model, the atmosphere was set in an ammonia-containing atmosphere, and the nitrogen amount was set to 0.02%. Next, after applying an annealing separator mainly composed of MgO,
Finish annealing was performed for 0 hours. FIG. 3 shows the magnetic properties (iron loss: W _17/50 ) in the longitudinal direction of the product. FIG. 3 shows that controlling the annealing pattern of the decarburizing annealing based on the material model stabilizes the magnetic characteristics without being affected by the uneven heating in the hot rolling process due to the skid.

Example 2 Si: 3.2%, C: 0.0
5%, acid-soluble Al: 0.025%, N: 0.007
%, Mn: 0.1%, S: 0.007%, Cr: 0.1
%, Sn: 0.05%, silicon steel slab (steel 1) and Si: 3.2%, C: 0.05%, acid-soluble Al: 0.027%, N: 0.008% , Mn: 0.
1%, S: 0.008%, Cr: 0.1%, Sn: 0.
1150 ° C silicon steel slab (steel plate 2) containing 04%
For 30 seconds, and hot-rolled to a thickness of 2.3 mm. Thereafter, the hot-rolled sheet was annealed at 1120 ° C. and then cold-rolled to a final sheet thickness of 0.23 mm. Based on the components of these materials and the history of hot rolling and subsequent annealing, first, the precipitate grain size (such as AlN) and the ferrite grain size of each part of the steel sheet before cold rolling were calculated. Next, the temperature history at the time of cold rolling was input together with these data to calculate the primary recrystallization annealing temperature at which the average primary recrystallization grain size was constant at 25 μm. After annealing at a soaking temperature of 840 ° C. for 90 seconds, , Rapid heating (100 ℃
/ sec) in the temperature range of 860 to 880 ° C. for 30 seconds in the longitudinal direction. Therefore,
Decarburization annealing was performed by connecting the two coils described above and changing the annealing pattern in the longitudinal direction based on this material model. For comparison, all the coils were annealed at 850 ° C. for 120 seconds. These coils were annealed in an ammonia-containing atmosphere to reduce the nitrogen content to 0.02%, and then an annealing separator containing MgO as a main component was applied, followed by finish annealing at 1200 ° C. for 20 hours.

Table 3 shows the magnetic properties in the longitudinal direction of the product.
From Table 3, it can be seen that controlling the decarburizing annealing pattern based on the material model stabilizes the magnetic properties in the longitudinal direction.

[0048]

[Table 3]

[0049]

According to the present invention, it is possible to reduce the variation in the operation of the steel making and hot rolling processes and to manufacture a grain-oriented electrical steel sheet having industrially stable magnetic properties.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a material prediction model system.

[Figure 2] product of the magnetic flux density after annealing finish the decarburization annealing annealing cycle: is a table showing the relationship of B _8.

FIG. 3 (a) shows a longitudinal magnetic property (iron loss: W) of a product in which an annealing pattern of decarburizing annealing is controlled based on a material model.
_17/50 ). (B) the longitudinal direction of the magnetic properties of the products was not controlled annealing pattern (iron loss: W _17/50) table showing.

Claims (2)

[Claims] 1. Content of Si: 0.8-4.8%, C: 0.085% or less, Acid-soluble Al: 0.01-0.065%, N: 0.012% or less by weight% Then, the silicon steel slab consisting of the balance of Fe and unavoidable impurities is heated at a temperature of 1280 ° C. or less and hot-rolled, and then subjected to one or two or more cold-rollings including annealing to obtain a final sheet thickness, and decarburizing annealing. In the method for producing a grain-oriented electrical steel sheet subjected to finish annealing, at least 6
Heat up to 50 ° C at an average heating rate of 10 to 40 ° C / sec,
Then, heating to a temperature calculated based on the material prediction model at a heating rate of 60 ° C./sec or more to adjust the average grain size of the primary recrystallized structure, and then performing a nitriding treatment, thereby stabilizing the magnetic characteristics. Manufacturing method of grain-oriented electrical steel sheet. 2. In% by weight, Si: 0.8 to 4.8%, C: 0.085% or less, acid-soluble Al: 0.01 to 0.065%, N: 0.012% or less Then, after the silicon steel slab consisting of the balance of Fe and unavoidable impurities is heated at a temperature of 1280 ° C. or less and hot-rolled, the steel sheet is subjected to one or two or more cold rolling operations including annealing to obtain a final sheet thickness, and decarburized annealing. In the method for producing a grain-oriented electrical steel sheet to be subjected to finish annealing, a temperature of 60 ° C.
Directional electromagnetic with stable magnetic characteristics characterized by heating at a heating rate of / sec or more to the temperature calculated based on the material prediction model, adjusting the average grain size of the primary recrystallization structure, and then performing nitriding treatment Steel plate manufacturing method.