JPH09137224A - Production of grain-oriented silicon steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the magnetic properties of a silicon steel sheet and to improve its productivity by applying a cooling-heating cycle to hot rolled sheet annealing to a grain-oriented silicon steel sheet contg. Al and N as inhibitors and a specified amt. of Sb, and executing cold rolling at an ordinary temp. SOLUTION: A slab for a grain-oriented silicon steel sheet contg. Al and N as inhibitors and furthermore contg. >=0.03wt.% Sb is subjected to hot rolling, is next subjected to hot rolled sheet annealing, is thereafter subjected to each one time of cold rolling, decarburizing annealing and final finish annealing to obtain a grain-oriented silicon steel sheet. At this time, in the process of soaking in the temp. range of 1000 to 1180 deg.C in the hot rolled sheet annealing, a cooling-heating cycle to a temp. region lower by >=400 deg.C than the soaking temp. is applied, and if required, it is repeated for >= two times. Furthermore, the hot rolled sheet annealing is executed for >= two times according to necessary. The subsequent cold rolling is executed at an ordinary temp., e.g. of about 25 to 100 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a grain-oriented silicon steel sheet, and in particular, intends to realize improvement of magnetic characteristics together with improvement of productivity by adding a device to hot-rolled sheet annealing. .

[0002]

2. Description of the Related Art Oriented silicon steel sheets are used as soft magnetic materials.
It is mainly used as an iron core material for transformers and rotating machines, and is required to have high magnetic flux density as magnetic characteristics and small iron loss and magnetostriction. Such a grain-oriented silicon steel sheet has an inhibitor necessary for secondary recrystallization, such as Mn.
After heating a slab for grain-oriented silicon steel sheet containing S, MnSe, AlN, etc., hot rolling it, and then subjecting it to hot-rolled sheet annealing, if necessary, once or two or more times with intermediate annealing sandwiched. It is manufactured by cold rolling to a final product thickness, decarburization annealing, applying an annealing separator such as MgO to the steel sheet, and then performing final finishing annealing. On the surface of grain-oriented silicon steel, except for special cases, forsterite (Mg ₂ Si
O ₄ ) It is common that a quality insulating film is formed. This coating contributes not only to electrical insulation of the surface but also to improvement of iron loss and magnetostriction by imparting tensile stress to the steel sheet by utilizing its low thermal expansion property.

In this method for producing a grain-oriented silicon steel sheet, there is known a technique for prescribing the conditions for hot-rolled sheet annealing in order to keep the magnetic characteristics stable and good over the entire length of the coil.
For example, in Japanese Unexamined Patent Publication No. 57-198214 (manufacturing method of high magnetic flux density grain-oriented electrical steel sheet), the precipitation dispersed phase is
In the basic component system using MnS and AlN, hot-rolled sheet annealing is performed at a heating rate of 2-10 ° C / s from 800 ° C to 1080-1200 ° C during the heating process. In this soaking temperature range
In the cooling process after keeping the temperature for 60 seconds or less, the residence time from the soaking temperature range to the temperature range of 900 to 980 ° C is set to 20 seconds or more and 500 seconds or less, and then to room temperature at a cooling rate of 10 ° C / s or more. Techniques characterized by rapid cooling have been proposed. The idea of this technology is that the heating rate of 800 ℃ or more
Si ₃ N ₄ precipitated on the hot-rolled sheet during this heating process at ℃ / s
At the same time as decomposing the AlN, AlN is precipitated to an optimum size, and coarsening of the precipitate is prevented by limiting the soaking time to within 60 seconds, and the soaking temperature range from 900 to 980 ° C The purpose of this is to control the cooling so that AlN can be sufficiently precipitated. In other words, control of AlN precipitation is the central technical idea.

On the other hand, in Japanese Unexamined Patent Publication No. 6-235027 (method for producing a grain-oriented silicon steel sheet having good magnetic properties), in a heat cycle of hot-rolled sheet annealing, a heating rate of 5 ° C./s or more is used. After heating in the temperature range of 1100 to 1180 ℃,
It is characterized by repeating a heating cycle for cooling to a temperature range of 800 to 1050 ° C at a cooling rate of 5 ° C / s or more at least once and then maintaining the temperature soaking for 20 to 300 seconds in a temperature range of 800 to 1050 ° C. The technology to do is proposed. The idea of this technology is to accelerate the γ → α transformation by maintaining the cooling / heating cycle and maintaining the temperature from 800 ° C to 1050 ° C during the soaking of hot-rolled sheet to eliminate the structure such as pearlite which is harmful to the structure formation, and , To increase solid solution C and carbide in the crystal grains. The formation of such solid solution C and precipitated carbide is carried out by performing the final cold rolling by warm rolling as disclosed in Japanese Patent Publication No. 50-26493 (cold rolling method for high magnetic flux density unidirectional electrical steel sheet). It can be said that the technique is based on the prescription of aging between time and passes, but the specification does not describe the condition although the combination with cold rolling is presented.

However, for the cold rolling for carrying out this method, it is usual to use a Sendzimir mill capable of performing reverse rolling, which is significantly inferior in productivity to tandem rolling. Therefore, the above-mentioned technique may be a combination of techniques such as hot-rolled sheet annealing and warm rolling, and is not a technique that does not require warm rolling and eventually reverse rolling which is inferior in productivity.

[0006]

SUMMARY OF THE INVENTION The present invention advantageously solves the above-mentioned problems, and further improves the components and the annealing of hot-rolled sheet to reduce the productivity in cold rolling. An object of the present invention is to propose an advantageous manufacturing method capable of obtaining a grain-oriented silicon steel sheet having excellent magnetic properties even in tandem rolling.

[0007]

The background of the invention is described below based on experimental examples.

The inventors first conducted various experiments and studies on the composition of components and the annealing pattern of hot-rolled sheet. As a result, it was newly found that the need for warm rolling can be eliminated by carrying out hot-rolled sheet annealing twice with a component composition containing a relatively large amount of Sb, as described below. C: 0.07 wt%, Al: 0.025 wt%, N: 0.
In the manufacturing process of the grain-oriented silicon steel sheet with a final thickness of 0.34 mm, using a 3 wt% Si ingot containing Sb: 0.05 wt% and Sb: 0.05 wt%, cold rolling at room temperature by changing the annealing conditions of the hot rolled sheet Experiments were conducted to find suitable conditions.

The experimental results are summarized in Table 1.

[Table 1]

In Table 1, cold rolling is performed in a tandem mill using rolls and strip coolant at a temperature of 50 ° C., and warm rolling is performed in a reverse mill by reducing the amount of the coolant. It was rolled at a temperature of 200 ° C.

As is clear from Table 1, the hot rolled sheet annealing
It has been found that when the rolling is performed once, even if cold rolling is performed at room temperature, magnetic characteristics equivalent to or higher than those obtained when cold rolling is performed at a conventional temperature are obtained.

However, since the above method has a disadvantage that the hot-rolled sheet annealing is performed twice from the viewpoint of productivity, the heat pattern in the hot-rolled sheet annealing was further examined. First, as a simple idea, we investigated the extension of the soaking time and the raising of the soaking temperature in hot-rolled sheet annealing. The experimental results are summarized in Table 2 (extended time) and Table 3 (increased temperature).

[0013]

[Table 2]

[0014]

[Table 3]

The composition and final plate thickness of the steel ingots used in Tables 2 and 3 are the same as those in Table 1, and cold rolling is performed at room temperature (temperature: 50 ° C.) for tandem rolling. It was

As is clear from Tables 2 and 3, in both cases of extending the soaking time and raising the soaking temperature,
Currently used as a high magnetic flux density grain-oriented silicon steel sheet
The magnetic flux density (B ₈ ) characteristics exceeding 1.93 T were not obtained.

Therefore, it is considered that the hot-rolled sheet annealing may be performed twice, so that cooling is performed during the soaking (temperature: 1125 ° C. time: 2 minutes) of the normal hot-rolled sheet annealing.
A heat pattern having a region where the temperature was lowered by adding a heating cycle was devised and various experiments were conducted. FIG.
Fig. 2 shows a schematic diagram of a heat pattern in annealing a hot rolled sheet.

The experimental results are summarized in Table 4.

[Table 4]

In Table 4, cold rolling was carried out at room temperature (temperature: 50 ° C.), and the temperature drop ΔT during annealing of the hot rolled sheet is represented by the following equation. ΔT = annealed temperature of hot-rolled sheet annealing (1125 ° C.)-Lowering reaching temperature in low temperature region Table 4 also shows a material of two-pass hot-annealed sheet annealing at 1150 ° C. for 2 minutes.

Further, the influence of the cold rolling temperature in the annealed hot rolled sheet having a low temperature region during the soaking was investigated. At this time, the hot-rolled sheet is annealed at a soaking temperature: 1125.
℃, low temperature region reaching temperature: 625 ℃ (falling temperature difference ΔT:
500 ° C).

The results of the investigation are summarized in Table 5.

[Table 5]

The composition of the steel ingots used in the experiments shown in Tables 4 and 5 was the same as in Table 1, and the final plate thickness was 0.34 mm, which was the same as in Table 1.

As is clear from Tables 4 and 5, warm rolling is not performed by providing a temperature region lower than the soaking temperature of 400 ° C. or more (ΔT) during soaking during hot-rolled sheet annealing. That is, it has been found that stable magnetic properties can be obtained stably by cold rolling at room temperature.

As described above, by performing the hot-rolled sheet annealing twice or by providing a temperature region lower than the soaking temperature of 400 ° C. or higher during the soaking of the hot-rolled sheet annealing, and by cold rolling at room temperature. The reason why excellent magnetic properties are obtained is presumed as follows. By performing the hot-rolled sheet annealing twice or by providing a low temperature region of 400 ° C. or higher during the annealing, the steel sheet undergoes at least two α-γ transformations. As a result, the coarse pearlite and cementite structures of the steel sheet can be uniformly solid-dissolved and precipitated. As a result, the amount of solid solution C before cold rolling is greatly increased as compared with normal hot plate annealing,
It is considered that the optimum rolling temperature appears on the low temperature side. Furthermore, although the mechanism of Sb is under investigation, it is believed that it segregates at the grain boundaries and increases the amount of carbon solid solution in the grains.

Thus, the present invention is based on the above findings, and the gist thereof is as follows.

A slab for grain-oriented silicon steel sheet containing Al and N as main inhibitor components and containing Sb in an amount of 0.03 wt% or more was hot-rolled, then hot-rolled sheet was annealed, and then cold-rolled once. After making the final plate thickness by, apply decarburization annealing, then apply the annealing separator, and then, in the process of producing the grain-oriented silicon steel sheet by the series of steps of performing the final finish annealing, 1) Add a cooling / heating cycle up to a temperature lower than the soaking temperature by 400 ° C or more during soaking in the temperature range of 1000 to 1180 ° C 2) Cold rolling is performed at room temperature Method for manufacturing grain-oriented silicon steel sheet (first invention).

The method for producing a grain-oriented silicon steel sheet according to the first aspect of the invention (the second aspect of the invention), characterized in that the cooling / heating cycle is repeated twice or more during the soaking of the hot-rolled sheet.

A slab for grain-oriented silicon steel sheet containing Al and N as main inhibitor components and containing Sb in an amount of 0.03 wt% or more was hot-rolled, then hot-rolled sheet was annealed, and then cold-rolled once. After making the final plate thickness by, apply decarburization annealing, then apply the annealing separator, and then, in the process of producing the grain-oriented silicon steel plate by the series of steps of performing the final finishing annealing, 1) hot-rolling plate annealing Performing two or more times 2) A method for producing a grain-oriented silicon steel sheet, characterized in that cold rolling is performed at room temperature (third invention).

Here, in the cold rolling step performed at room temperature, the aging effect is unnecessary as in the above-mentioned prior art, and the temperature is preferably in the range of 25 to 100 ° C.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION First, the reasons for limiting the component composition range of the grain-oriented silicon steel sheet material and the preferred component composition range will be described.

C: 0.02 to 0.15 wt% C is an important component for improving the crystal structure by utilizing the α-γ transformation during hot rolling, but the content is 0.02 wt%.
%, The addition effect is poor, and if a large amount is added in excess of 0.15 wt%, subsequent decarburization becomes difficult.
Its content is preferably in the range of 0.02 to 0.15 wt%.

Si: 2.0-4.5 wt% Si is a useful component for improving the iron loss characteristics by increasing the electric resistance of the steel sheet, but if the content is less than 2.0 wt%, the electric resistance of the steel sheet will be low. Good iron loss characteristics cannot be obtained because the size decreases and eddy current loss increases. On the other hand, if it exceeds 4.5 wt%, cold rolling becomes difficult. Therefore, its content is preferably in the range of 2.5 to 4.5 wt%.

In addition to C and Si, in the grain-oriented silicon steel sheet material, only grains having a Goss orientation are selectively grown by suppressing grain growth other than the Goss orientation from the primary recrystallization structure. That is, it is essential to include a component forming an inhibitor having an essential function for secondary recrystallization. Two types of inhibitors are known, one that functions as a fine precipitate such as AlN, MnSe, and MnS, and the other that functions by segregating at grain boundaries such as Sb and Sn. Of these, the AlN inhibitor is essential in the present invention. This is because the cold rolling one-time method inevitably increases the rolling reduction, but under such high pressure rolling, the AlN inhibitor is particularly advantageous.

In order to obtain a suitable amount of AlN inhibitor, sol.Al: 0.01 to 0.05 wt% and N: 0.004, respectively.
~ 0.012 wt% is preferable. Because Al
If the content is less than 0.01 wt%, the magnetic flux density will decrease.
This is because secondary recrystallization becomes unstable when it exceeds 0.05 wt%, and when the N content is less than 0.004 wt%, the amount of AlN inhibitor is insufficient and the magnetic flux density decreases, while 0.012 wt%.
This is because when it exceeds%, the products often have surface defects called blister.

In the present invention, so-called MnSe such as MnSe and MnS is contained as long as it contains AlN as the main inhibitor.
There is no problem in using Se-based inhibitors together. Here, the preferable range of each forming component of the MnSe-based inhibitor is as follows.

Mn: 0.03 to 0.30 wt% When the content of Mn is less than 0.03 wt%, the absolute amount of Mn is insufficient as an inhibitor component. descend. Therefore, the content is preferably in the range of 0.03 to 0.30 wt%.

Se and / or S: 0.01 to 0.05 wt% If the content of Se and S is less than 0.01 wt%, the absolute amount is insufficient as an inhibitor component, while if it exceeds 0.05 wt%, purification by finish annealing is performed. Therefore, the content of each is 0.01 to 0, either alone or in combination.
The range of 05 wt% is suitable.

Further, the present invention is characterized by using Sb which is a grain boundary segregation type inhibitor. The grain boundary segregation-type inhibitor component of Sb here has a small effect of improving the magnetic properties when the content thereof is too small, and the content thereof is 0.03 wt.
% Or more is required. On the other hand, if the amount is too large, embrittlement and adverse effects on the forsterite coating occur, so the upper limit of the content is 0.
30 wt% is preferable. Furthermore, in order to prevent surface defects due to surface embrittlement during hot rolling, 0.10 wt%
It is also effective to add the following Mo.

Next, in the production of the grain-oriented silicon steel sheet which is the subject of the present invention, the molten steel obtained by the conventional steelmaking method is cast by, for example, the continuous casting method or the ingot casting method, and if necessary, After forming a slab by interposing the slabbing process and uniformly heating it in the plate thickness direction to 1350 ° C. or more in an induction heating furnace, hot rolling is performed and hot rolled sheet annealing conforming to the present invention is performed. Then, the cold-rolled sheet having the final thickness is obtained by cold rolling at room temperature by the cold rolling method. Following this, decarburization annealing is performed, an annealing separating agent containing MgO as the main component is applied, and then
Final finish annealing is performed at a temperature of about 1200 ° C, and the product is subjected to tensioning coating.

The hot rolled sheet annealing conditions applicable to the present invention are lower than the soaking temperature by 400 ° C. or more by adding a cooling / heating cycle during soaking in the temperature range of 1000 to 1180 ° C. By providing a low temperature region, repeating the cooling / heating cycle twice or more during the soaking, or performing hot-rolled sheet annealing twice or more. By performing hot-rolled sheet annealing such as these Combined with the inclusion of 0.03 wt% or more of Sb, final cold rolling at room temperature can be performed to obtain a product having excellent magnetic properties.

In the above hot-rolled sheet annealing, the soaking temperature is 10
If it is less than 00 ° C, the amount of γ-transformation is small and the improvement of the structure is insufficient and good magnetic properties cannot be obtained.
The precipitation dispersed phase of S, MnSe, etc. becomes coarse and the magnetic properties deteriorate, so the range was set to 1000 to 1180 ° C.

The addition of a cooling / heating cycle in the course of soaking is, for example, first performed by the inventor in Japanese Patent Laid-Open No. 59-1932.
As disclosed in the proposal in Japanese Patent No. 19, a pair of turn roll groups that alternately pass through the steel plates and make detours are installed with a heat insulating material sandwiched between them, and one turn roll group side is a heating zone and the other turn is a turn band. This can be extremely easily performed by using a continuous annealing facility using the roll group as a cooling zone.

[0043]

【Example】

Example 1 C: 0.079% by weight, Si: 3.35%, Mn: 0.069%, S
e: 0.023%, Al: 0.023%, N: 0.0083%, Cu: 0.13
%, Sb: 0.035% and the balance being essentially Fe. After heating a silicon steel slab in an induction heating furnace at 1430 ° C for 30 minutes,
It was hot rolled into a hot rolled sheet with a thickness of 2.2 mm. This hot-rolled sheet was divided into two parts, one under conditions of 1100 ° C for 1 minute (comparative example), and the other under conditions of adding a pattern of decreasing temperature to 550 ° C during soaking at a temperature of 1100 ° C (compliance example). ), And each hot-rolled sheet was annealed. Regarding cooling after soaking, both were mist-cooled from 800 ° C to 400 ° C at a cooling rate of 20 ° C / s. After that, both were finished by cold rolling at room temperature (temperature: 50 ° C) to a plate thickness of 0.35 mm. Then 840 ° C
Decarburization annealing was performed for 2 minutes, MgO was applied, and finish annealing was performed at 1200 ° C for 10 hours to obtain a product. The magnetic properties of the product thus obtained are shown in Table 6.

[0044]

[Table 6]

Example 2 C: 0.079%, Si: 3.35%, Mn: 0.069%, S by weight%
e: 0.023%, Al: 0.023%, N: 0.0083%, Cu: 0.13
%, Sb: 0.050% and the balance substantially consisting of Fe. After heating a silicon steel slab at 1430 ° C for 30 minutes in an induction heating furnace,
It was hot rolled into a hot rolled sheet with a thickness of 2.2 mm. This hot-rolled sheet is divided into two parts, one under conditions of 1000 ° C for 1 minute (comparative example), and the other under conditions of adding a pattern in which the temperature drops to 550 ° C during soaking at a temperature of 1000 ° C (compliance example) ), And each was hot-rolled and annealed. Regarding cooling after soaking, both were mist-cooled from 800 ° C to 400 ° C at a cooling rate of 20 ° C / s. After that, both were finished by cold rolling at room temperature (temperature: 40 ° C) to a plate thickness of 0.30 mm. Then 840 ℃ ・ 2
After decarburization annealing for 1 minute, MgO was applied and finish annealing was performed at 1200 ° C for 10 hours to obtain a product. Table 7 shows the magnetic properties of the products thus obtained.

[0046]

[Table 7]

Example 3 C: 0.079% by weight, Si: 3.35%, Mn: 0.069%, S
e: 0.023%, Al: 0.023%, N: 0.0083%, Cu: 0.13
%, Sb: 0.035% and the balance being essentially Fe. After heating a silicon steel slab in an induction heating furnace at 1430 ° C for 30 minutes,
It was hot rolled into a hot rolled sheet with a thickness of 2.0 mm. This hot-rolled sheet is divided into two parts, one under conditions of 1100 ° C for 1 minute (comparative example), and the other under conditions where a pattern of decreasing temperature to 650 ° C is added during soaking at a temperature of 1100 ° C (comparative example). ), And each hot-rolled sheet was annealed. Regarding cooling after soaking, both were mist-cooled from 800 ° C to 400 ° C at a cooling rate of 20 ° C / s. After that, both were finished by cold rolling at room temperature (temperature: 40 ° C) to a plate thickness of 0.27 mm. Then 840 ° C
Decarburization annealing was performed for 2 minutes, MgO was applied, and finish annealing was performed at 1200 ° C for 10 hours to obtain a product. Table 8 shows the magnetic properties of the products thus obtained.

[0048]

[Table 8]

Example 4 C: 0.079% by weight, Si: 3.35%, Mn: 0.069%, S
e: 0.023%, Al: 0.023%, N: 0.0083%, Cu: 0.13
%, Sb: 0.035% and the balance being essentially Fe. A silicon steel slab was heated at 1430 ° C. for 30 minutes in an induction heating furnace and hot-rolled into a hot-rolled sheet having a thickness of 1.8 mm. This hot-rolled sheet was divided into two parts, and one was placed at 1100 ° C for 1 minute (comparative example).
On the other hand, hot-rolled sheet annealing was carried out under the condition that a pattern of decreasing the temperature to 400 ° C was added during soaking at a temperature of 1100 ° C (compliance example). For cooling after soaking, both are 80
Mist cooling was performed from 0 ° C to 400 ° C at a cooling rate of 20 ° C / s. After that, both were finished by cold rolling at room temperature (temperature: 60 ° C) to a plate thickness of 0.23 mm. Then, decarburization annealing was performed at 840 ° C for 2 minutes, MgO was applied, and finish annealing was performed at 1200 ° C for 10 hours to obtain a product. The magnetic properties of the product thus obtained are shown in Table 9.

[0050]

[Table 9]

Example 5 C: 0.079% by weight, Si: 3.35%, Mn: 0.069%, S
e: 0.023%, Al: 0.023%, N: 0.0083%, Cu: 0.13
%, Sb: 0.035% and the balance being essentially Fe. After heating a silicon steel slab in an induction heating furnace at 1430 ° C for 30 minutes,
It was hot rolled into a hot rolled sheet with a thickness of 1.8 mm. This hot-rolled sheet is divided into two parts, one under conditions of 1100 ° C for 1 minute (comparative example), and the other under conditions of adding a pattern of temperature decrease to 400 ° C during soaking at a temperature of 1100 ° C (compliance example) ), And each hot-rolled sheet was annealed. Regarding cooling after soaking, both were in-air cooling. At this time, the cooling rate from 800 ° C to 400 ° C was 2 ° C / s. After that, both were finished by cold rolling at room temperature (temperature: 55 ° C) to a plate thickness of 0.23 mm. Then, decarburization annealing was performed at 840 ° C for 2 minutes, MgO was applied, and finish annealing was performed at 1200 ° C for 10 hours to obtain a product. Table 10 shows the magnetic properties of the products thus obtained.

[0052]

[Table 10]

Example 6 C: 0.079% by weight, Si: 3.35%, Mn: 0.069%, S
e: 0.023%, Al: 0.023%, N: 0.0083%, Cu: 0.13
%, Sb: 0.035% and the balance being essentially Fe. After heating a silicon steel slab in an induction heating furnace at 1430 ° C for 30 minutes,
It was hot rolled into a hot rolled sheet with a thickness of 2.2 mm. This hot-rolled sheet was divided into two, one under the condition of 1100 ° C for 1 minute (comparative example), and the other under the condition of adding a pattern of repeated temperature decrease to 550 ° C twice during soaking at a temperature of 1100 ° C. (Compatible example), hot rolled sheet annealing was performed. Regarding cooling after soaking, both were mist-cooled from 800 ° C to 400 ° C at a cooling rate of 20 ° C / s. After that, both were finished by cold rolling at room temperature (temperature: 50 ° C) to a plate thickness of 0.35 mm.
Then, decarburization annealing was performed at 840 ° C for 2 minutes, and MgO was applied.
Finished annealing was performed at 1200 ℃ for 10 hours to obtain a product. Table 11 shows the magnetic properties of the products thus obtained.

[0054]

[Table 11]

Example 7 C: 0.079% by weight, Si: 3.35%, Mn: 0.069%, S
e: 0.023%, Al: 0.023%, N: 0.0083%, Cu: 0.13
%, Sb: 0.035% and the balance being essentially Fe. After heating a silicon steel slab in an induction heating furnace at 1430 ° C for 30 minutes,
It was hot rolled into a hot rolled sheet with a thickness of 2.2 mm. This hot-rolled sheet was divided into two, one of which was annealed at 1100 ° C for 1 minute (comparative example), and the other was annealed twice at 1100 ° C for 1 minute. For the cooling after soaking, the first time is 80 in the mist.
Cooling at 0 ℃ to 400 ℃ at 20 ℃ / s, the second time at 2 ℃ in air
Air cooling of / s was performed. After that, both are at room temperature (temperature: 40 ℃)
Finished to a thickness of 0.35 mm by cold rolling. 840
Decarburization annealing at ℃ · 2 minutes, apply MgO and 1200 ℃ · 10
Finish annealing was performed for a time to obtain a product. Table 12 shows the magnetic properties of the products thus obtained.

[0056]

[Table 12]

As is apparent from Tables 6 to 12, the conforming examples of the present invention have extremely excellent magnetic properties as compared with the comparative examples. It shows that good magnetic properties can be stably obtained even by cold rolling technology at room temperature that can be rolled in a tandem mill by the hot-rolled sheet annealing method in which the dispersion and crystal structure, and further the dispersion of carbide are improved. is there.

[0058]

The present invention contains 0.03 wt% or more of Sb,
In producing a grain-oriented silicon steel sheet with AlN as the main inhibitor, the hot rolling sheet annealing conditions are specified and cold rolling is performed at room temperature.According to the present invention, the productivity is reduced in cold rolling. It is possible to adopt tandem rolling that does not cause it, and it is possible to manufacture grain-oriented silicon steel sheets with excellent productivity and magnetic properties.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a heat pattern of hot-rolled sheet annealing.

Claims (3)

[Claims] 1. A slab for grain-oriented silicon steel sheet containing Al and N as main inhibitor components and containing 0.03 wt% or more of Sb is hot-rolled and then annealed once after hot-rolled sheet annealing. After the final thickness is obtained by hot rolling, decarburization annealing is applied, then an annealing separator is applied, and then final finishing annealing is performed. Add a cooling / heating cycle up to a temperature lower than the soaking temperature by 400 ° C or more during soaking in the temperature range of 1000 to 1180 ° C of annealing 2) Cold rolling at normal temperature And a method for manufacturing a grain-oriented silicon steel sheet. 2. The method for producing a grain-oriented silicon steel sheet according to claim 1, wherein a cooling / heating cycle is repeated twice or more during the soaking of the hot-rolled sheet. 3. A slab for grain-oriented silicon steel sheet containing Al and N as main inhibitor components and containing 0.03 wt% or more of Sb is hot-rolled and then annealed once after hot-rolled sheet annealing. After the final thickness is obtained by hot rolling, decarburization annealing is applied, then an annealing separator is applied, and then final finishing annealing is performed. Annealing is performed twice or more. 2) A method for manufacturing a grain-oriented silicon steel sheet, which comprises performing cold rolling at room temperature.