JP2750238B2 - Method for producing grain-oriented silicon steel sheet having crystal orientation integrated in Goss orientation - Google Patents

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 having a crystal orientation integrated in a Goss orientation.

[0002]

2. Description of the Related Art Oriented silicon steel sheets have better magnetic properties than non-oriented silicon steel sheets, and are mainly used as transformer cores. {110} <0 by Goss
Since the invention of a method for producing a grain-oriented silicon steel sheet having crystal grains aligned in the <01> orientation, many methods for producing a grain-oriented silicon steel sheet having such a Goss structure have been proposed. These proposals can be broadly summarized into the following three.

[0003] The first method is a method called twice cold pressure method. This method is a modification of the Goss method, in which Mn, Sb, S, Se, etc. are added at the steelmaking stage, and secondary recrystallization is performed by utilizing the effect of these elements and their fine precipitates to suppress the growth of crystal grains. It is also done. Specifically, C:
0.02 to 0.08 wt%, Si: 2.0 to 4.0 wt%
%, Mn: about 0.2 wt%, S: 0.005 to 0.0
A steel ingot having a composition of 5 wt% is melted and rolled to a plate thickness of 2.0 to 3.0 mm by hot rolling, and then subjected to hot rolling annealing, and then to cold rolling at a rolling ratio of about 70%, 85
Intermediate annealing at 0 to 1050 ° C is performed, and the rolling reduction is 60 to
Cold rolling at 70%, decarburizing annealing at 800 to 850 ° C, annealing at 1100 ° C or higher for 5 to 50 hours to perform secondary recrystallization and removal of inhibitor (purification annealing),
Growing ss grains (for example, Japanese Patent Publication No. 51-13469)
issue).

[0004] The second method is a method called a one-time cold pressure method. In this method, the number of cold rolling is set to one,
It is known that the degree of accumulation of Goss grains is higher than that of the recooling method. Specifically, C: 0.02 to 0.08 wt%, S
i: 2.0 to 4.0 wt%, Mn: about 0.2 wt%,
1. A steel ingot having a composition of about N: 0.01 to 0.05 wt% and Al: about 0.1 wt% is melted and hot-rolled to obtain a sheet thickness of 2.
After rolling to 0 to 3.0 mm, hot-rolled sheet annealing is performed to perform AlN precipitation treatment, then cold rolling is performed at a rolling ratio of 80 to 95%, decarburizing annealing is performed, and then at 1200 ° C. 2
The secondary recrystallization and removal of the inhibitor (purification annealing) are performed by high-temperature annealing for 0 hour to grow Goss grains (for example, Japanese Patent Publication No. 40-15644).

[0005] A third method is to use Go without an inhibitor.
This is a method of forming an ss structure (see, for example,
5339, JP-A-2-57635, etc.). In this method, Goss grains are developed by simply combining rolling and heat treatment under specific conditions.

[0006]

As described above, first,
Since the second method requires decarburization annealing and purification annealing, annealing at high temperature for a long time is indispensable. Because of this, manufacturing costs,
It is inevitable that equipment costs will increase.

If the final sheet thickness is reduced to 0.20 mm or less in order to reduce iron loss, the secondary recrystallization phenomenon becomes unstable and it is difficult to occupy the entire surface with Goss grains. For this reason, the production limit is currently about 0.23 mm in thickness.

Since the third method does not require decarburizing annealing and purification annealing, it is more advantageous in terms of manufacturing cost than the first and second methods. However, the inventors of the present application disclose Japanese Patent Application Laid-Open Nos. 64-55339 and 2-57635.
In addition to the method disclosed in
The ss grain growth mechanism was extremely unstable, and it was found that it was not always possible to obtain a material covered entirely with Goss grains, and it was difficult to obtain stable quality. Goss stable
Grain generation is practically indispensable for grain oriented silicon steel sheets, and even if it is used except for portions other than Goss grains, the cost is increased due to a decrease in yield.

The present invention has been made in view of such circumstances, and it is possible to manufacture a grain-oriented silicon steel sheet having a crystal orientation integrated with a Goss orientation having excellent magnetic properties at low manufacturing cost. It is intended to provide a manufacturing method.

[0010]

According to the present invention, C: 0.01
wt% or less, Si: 2.5 to 7.0 wt%, S: 0.0
1 wt% or less, Al: 0.01 wt% or less, N: 0.0
A steel material containing 1 wt% or less is prepared, and this steel material is
C. or higher, followed by hot rolling so that the finishing temperature becomes 700 to 950.degree. C., and then subjected to primary cold rolling at a rolling reduction of 40% or more, followed by primary annealing at a temperature of 600 to 900.degree. Further, a secondary cold rolling is performed at a rolling ratio of 50 to 80%, and then the reducing atmosphere or the oxygen partial pressure is reduced to 0.5%.
Non-oxidizing atmosphere of Pa or less, or oxygen partial pressure of 0.5 Pa
A method for producing a grain-oriented silicon steel sheet having a crystal orientation integrated in a Goss orientation, characterized by performing secondary annealing at a temperature of 1000 to 1300 ° C. in the following vacuum.

Further, the steel material after the secondary annealing is further subjected to tertiary cold rolling at a rolling reduction of 30% or more, and subsequently a reducing atmosphere or a non-oxidizing atmosphere having an oxygen partial pressure of 0.5 Pa or less, or A method for producing a grain-oriented silicon steel sheet having a crystal orientation accumulated in a Goss orientation, wherein tertiary annealing is performed at a temperature of 1000 to 1300 ° C. in a vacuum having an oxygen partial pressure of 0.5 Pa or less.

In order to solve the above-mentioned problems, the inventors of the present application have presupposed a component system that does not require purification annealing, and have studied in detail the effects of components in steel, and rolling conditions and annealing conditions including hot rolling conditions. As a result, by defining the steel composition in a specific range, and further defining the above manufacturing conditions in a specific narrow range,
Finally, they have found that Goss grains grow stably and can cover the entire surface of the silicon steel sheet. The present invention having the above-described configuration has been made based on such findings of the present inventors.

[0013]

Hereinafter, the present invention will be described in detail. First,
The reasons for limiting the chemical components will be described.

C is preferably reduced as much as possible in the steel making stage from the viewpoint of magnetic properties. If C exceeds 0.01% by weight, the magnetic properties are significantly deteriorated. Therefore, the upper limit of C is set to 0.
It is defined as 01 wt%.

Si has an effect of increasing electric resistance and has an effect of 2.5
The metallurgical transformation point is eliminated by containing at least
It has the effect of making it a single phase. Further, at around 6.5 wt%, magnetostriction becomes zero, so that extremely excellent soft magnetic characteristics can be obtained. However, if it exceeds 7 wt%, magnetostriction increases again, magnetic properties deteriorate, and the material becomes extremely brittle, which is not practical. Therefore, the content of Si is set to 2.5 to 7.0 w.
It is specified in the range of t%.

S and N are typical elements contained in ordinary steel, and these elements can be formed in a solid solution state or a precipitate state because they inhibit grain growth. It is preferable to reduce as much as possible. However, if an extreme reduction is made at the steel making stage, it will cause an increase in cost. Therefore, the upper limits of these contents are respectively defined as 0.01 wt% as ranges that do not impair the grain growth.

Al is an element having a wide solid solubility in α-iron and a strong affinity for oxygen. Therefore, when the Goss structure is formed by the final heat treatment, it reacts with a trace amount of oxygen in the heat treatment atmosphere to form an oxide layer on the surface of the steel sheet, so that crystal grain growth due to surface energy is hindered. For this reason, the content of Al is set to 0.01 wt% or less at which such inconvenience does not occur. A more preferable range of the Al content is 0.005 wt% or less. Since Al is usually added as a deoxidizing agent, it needs to be strictly controlled. The idea of promoting the growth of Goss grains by controlling a small amount of Al, which is a general additive element, as described above was found by the present inventors for the first time.

Cu is an element having a small solid solubility in α-iron, and is an element that remarkably inhibits crystal grain growth when a Goss structure is formed by final heat treatment. Further, Cu is contained at about 0.05 wt% in the steel making stage. Therefore, the content is preferably reduced to 0.01 wt% or less, at which the above-mentioned inconvenience does not occur, and more preferably 0.005 wt% or less. However, Cu has a melting point of 1083.
° C, and is a component which is volatilized by heat treatment at about 1000 ° C or more. Therefore, even if it is contained more than 0.01 wt%, it can be reduced to 0.01 wt% or less by heat treatment for a relatively long time. However, extension of the heat treatment time is not preferable from the viewpoint of increasing the efficiency of the process.

The unavoidable impurity elements other than these elements can be contained in such an amount as to be contained in ordinary steel. However, from the viewpoint of further improving the magnetic characteristics and the like, it is preferable that the number is small. In particular, Sn or the like having a low solid solubility in α-iron remarkably inhibits crystal grain growth when a Goss structure is formed by final heat treatment similarly to Cu, so that the content is 0.01 wt.
%, Preferably 0.005 wt% or less. V, Zn, etc., which have a high solid solubility in α-iron and a strong affinity for oxygen, have an effect of inhibiting crystal grain growth by surface energy, similarly to Al, so that the content is 0.01 wt. %, Preferably 0.005 wt% or less. Further, since O in the steel affects the tertiary recrystallization behavior, it is desirably as low as possible, preferably 0.008 wt% or less. The basic element of other steels, M
It is preferable that n and P are also small.

The steel thus melted is cast into an ingot or made into a slab by a continuous casting method, and the ingot or the slab is kept at a temperature of 1000 ° C. or more and subjected to hot rolling. You. The holding temperature before hot rolling is specified to be 1000 ° C. or higher because recrystallization is promoted during hot rolling in a rough rolling mill or a preceding stage of a finishing hot rolling mill and a hot rolling finishing temperature of 700 to 950 ° C. is secured. To do that. The hot rolling may be performed after the ingot or slab is heated to 1000 ° C. or more in a heating furnace, or the slab temperature may be set to 1000 after continuous casting by direct rolling.
It may be carried out while the temperature is kept at not less than ° C.

The finishing temperature of hot rolling is 700-95.
It must be in the range of 0 ° C. Finish temperature 700
If the temperature is lower than 0 ° C., the rolling load of the hot rolling becomes too large, which is not preferable in production, and also adversely affects the final growth of Goss grains. Further, in order to make the finishing temperature higher than 950 ° C., it is necessary to set the initial temperature of the ingot or the slab higher, which is disadvantageous in manufacturing cost.

The thickness of the hot-rolled sheet varies depending on the desired thickness of the final product, but generally ranges from about 1.6 mm to about 5.0 mm. The hot-rolled sheet manufactured in this manner is wound according to a conventional method, and the winding temperature is preferably 560 to 800 ° C. When the winding temperature is lower than 560 ° C., cooling on the run-out table after the completion of hot rolling is practically difficult, and therefore, lacks practicality. The acidity deteriorates due to oxidation,
Not practical.

The rolled hot-rolled coil may be annealed in a continuous furnace or a batch furnace as required.
The hot-rolled sheet annealing temperature at this time is preferably 700 to 1100 ° C. If the hot-rolled sheet annealing temperature is less than 700 ° C,
Since the worked structure formed at the time of hot rolling cannot be eliminated, the effect is not substantially exhibited. On the other hand, if the hot-rolled sheet annealing temperature exceeds 1100 ° C., it causes high operating costs. This is a practical problem.

The hot rolled sheet thus obtained is subjected to primary cold rolling according to a conventional method. The rolling rate of this cold rolling is 40
% Or more. When the rolling reduction is less than 40%, the final product thickness (usually, 1.0 mm or less) is calculated based on the thickness of the normal hot-rolled sheet.
It is difficult to perform rolling to the maximum, and the effect of surface energy is relatively reduced. Therefore, sufficient grain growth cannot be caused by subsequent annealing. Normally, lubricating materials are used in cold rolling,
The same effect can be obtained even if rolling is performed without lubrication without using a lubricant.

The thus obtained primary cold-rolled sheet is 6
Annealing (primary annealing) at 00 to 900 ° C. If the annealing temperature is lower than 600 ° C., complete recrystallization by annealing cannot be performed. On the other hand, if the annealing temperature exceeds 900 ° C,
Although complete recrystallization is achieved, annealing costs are inevitably high. In addition, in order to perform recrystallization in a short time and secure economic efficiency, it is particularly preferable to perform annealing at a temperature of 680 to 800 ° C. In this annealing, even if the steel sheet surface is slightly oxidized, it can be removed by pickling before cold rolling performed later, so that the crystal orientation in the secondary or tertiary annealing is accumulated in the Goss orientation. There is no major problem in terms of securing However, from the viewpoint of preventing an oxide film from being formed excessively, it is preferable to perform the treatment in a non-oxidizing atmosphere or a vacuum having a low oxygen partial pressure as much as possible. There is no problem if the annealing time is usually 2 minutes or more. Such an annealing treatment can be performed by batch annealing or continuous annealing using a box furnace.

The heating conditions in the annealing treatment are suitably a heating rate of 200 to 500 ° C./min and a holding time of about 2 to 5 minutes for continuous annealing, and a heating rate of 4 to 20 for batch annealing.
C./min, and a holding time of 1 to 10 hours are appropriate. The cooling rate may be a normally adopted cooling rate as long as distortion due to heat shrinkage does not remain in the steel sheet. For example, 6
A cooling rate of 13.5 ° C / sec to 00 ° C and 12 ° C / sec to 300 ° C is employed.

The steel sheet subjected to the primary annealing has a rolling reduction of 5%.
Secondary cold rolling is performed at 0 to 80%. If the rolling ratio is less than 50% or more than 80%, the final accumulation of Goss grains is not sufficient. This cold rolling can be performed either without lubrication or with lubrication as in the case of primary cold rolling.

The secondary cold rolled sheet obtained in this way is 10
Annealing is again performed at a temperature of 00 to 1300 ° C (secondary annealing). If the annealing temperature is lower than 1000 ° C., the driving force for crystal grain growth utilizing surface energy is not sufficient, and the desired
You can't get a Goss organization. On the other hand, when the annealing temperature is 13
If the temperature exceeds 00 ° C., the energy cost required for such high-temperature heating becomes excessively large, causing a practical problem.

This secondary annealing is carried out in an atmosphere having a substantial reducing property in which hydrogen is contained in a necessary amount or an oxygen partial pressure substantially consisting of an inert gas such as nitrogen or Ar having a pressure of 0.5 Pa.
It is necessary to carry out in the following non-oxidizing atmosphere or in a vacuum having an oxygen partial pressure of 0.5 Pa or less. This is to prevent the formation of an oxide film on the steel sheet surface that hinders the integration of the crystal orientation in the Goss orientation. When oxygen is contained in a vacuum or an inert gas atmosphere so that the oxygen partial pressure exceeds about 0.5 Pa, an oxide film is formed on the surface of the steel sheet, and the above effects cannot be obtained. There is no problem if the annealing time is 2 minutes or more as in the primary annealing.

Although the secondary annealed sheet thus obtained exhibits high magnetic flux density characteristics (B ₈ ≧ 1.7 T or more) as it is, it is further enhanced by performing the third cold rolling and the third annealing. It shows magnetic properties.

The rolling reduction of the third cold rolling is set to 30% or more. If the rolling reduction is less than 30%, the crystal structure finally obtained does not have a desired Goss structure. In addition, the rolling rate is 5
In a range exceeding 0%, B ₈ shows a high magnetic flux density of 1.9 T or more. This cold rolling can be carried out without lubrication or lubrication as in the case of primary and secondary cold rolling.

The tertiary cold rolled sheet is annealed at a temperature of 1000 to 1300 ° C. (tertiary annealing). Also in this case, if the annealing temperature is lower than 1000 ° C., a desired Goss structure cannot be obtained because the driving force for crystal grain growth utilizing surface energy is not sufficient. On the other hand, if the annealing temperature exceeds 1300 ° C., the energy cost required for such high-temperature heating becomes substantially too large, causing a practical problem.
This annealing also needs to be performed in a reducing atmosphere or a non-oxidizing atmosphere with an oxygen partial pressure of 0.5 Pa or less, or in a vacuum with an oxygen partial pressure of 0.5 Pa or less for the same reason as the above-described secondary annealing. . There is no problem if the annealing time is 3 minutes or more,
Prolonged annealing forms a more stable Goss structure.

Each of the steel sheets obtained by the above method has a G
Oss grains accumulate stably. The above characteristics are 8
Each of the magnetic flux densities B ₈ when a magnetic field of 00 A / m is applied is 1.7 T or more, indicating excellent magnetic properties.

As described above, a steel sheet having excellent properties can be produced by the present invention only when a steel having a specific composition is subjected to a primary cold pressure, a primary annealing, a secondary cold pressure, or in addition to the secondary annealing. It is presumed that a preferred texture is formed by the tertiary cold pressure, and selective grain growth of Goss grains occurs by crystal growth using surface energy by secondary annealing or tertiary annealing.

If the conditions of the primary cold pressure, primary annealing, secondary cooling pressure, secondary annealing, and tertiary cold pressure deviate from the conditions of the present invention, the final annealing (secondary annealing or tertiary annealing) is performed according to the present invention. The result is that the crystal does not eventually become a coarse crystal, or the crystal orientation is not sufficiently integrated in the Goss orientation (the (100) plane is aligned with the plate surface, but the <001> axis is shifted from the rolling direction). turn into.

[0036]

【Example】

[Example 1] Steels having the chemical components shown in Table 1 were melted, and the finishing temperature: 820 ° C, the winding temperature: 600 ° C, and the finished plate thickness: 1.8.
The hot rolling was performed under the condition of mm. The hot-rolled sheet having a thickness of 1.8 mm produced in this manner is pickled to remove a surface oxide film, and then 40% (1 mm in thickness) to 85% (0.
(3 mm). Next, these steel sheets are heated at 600 to 900 ° C. in a non-oxidizing atmosphere.
For 1 hour.

FIG. 1 shows the DC magnetic characteristics (magnetic flux density B ₈ ) of the steel sheet at this stage. Figure 1 is a diagram showing a magnetic flux density B ₈ in the primary cold rolling ratio and primary annealing temperatures.
As shown in the figure, at this stage, the magnetic flux density B ₈ is 1.6.
Nothing exceeded T, and high magnetic flux characteristics were not obtained.

Next, all of these steel plates were 0.1 mm
To 2nd cold rolling. The cold rolling rate at this time is about 60
９０90%. Oxygen partial pressure of 0.5
Secondary annealing was performed at 1200 ° C. for 5 hours in a vacuum of Pa or less, and the DC magnetic properties after annealing were measured.

FIG. 2 shows the result. Figure 2 is a diagram showing the magnetic flux density B ₈ after the secondary annealing at each of the secondary cold rolling ratio and primary annealing temperatures. As shown in this figure, the rolling reduction of the secondary cold rolling is 80% or less, and the primary annealing temperature is 700 to 80.
At 0 ° C., it was confirmed that high magnetic properties with a magnetic flux density B ₈ of 1.7 T or more were obtained.

Example 2 Using the same hot-rolled sheets as in Example 1, pickling these steel sheets to remove the surface oxide film,
The primary cold rolling was performed in a range of 40% (sheet thickness 1 mm) to 85% (sheet thickness 0.3 mm). Next, these steel sheets were subjected to an annealing treatment at 700 ° C. for 1 hour in a non-oxidizing atmosphere.

Next, the steel sheet after the primary annealing has a rolling reduction of 5%.
After subjecting to secondary cold rolling of 0 to 90%, an oxygen partial pressure of 0.5
A secondary annealing treatment was performed at 1250 ° C. for 5 hours in a vacuum of Pa or less.

The DC magnetic properties of the steel sheet thus obtained were measured. FIG. 3 shows the result. Figure 3 is a diagram showing the values of the magnetic flux density B ₈ of the steel sheet after the secondary annealing in the case of changing the primary reduction ratio and the secondary reduction ratio, in the figure, indicated points in a white circle is {110} The steel plates that were not accumulated on the steel plate surface, and the points indicated by black circles indicate the steel plates with {110} accumulated on the steel plate surface.

As is clear from this figure, when the secondary cold rolling ratio exceeds 80%, no accumulation of {110} was observed, and it was confirmed that the value of the magnetic flux density was low. On the other hand, in the region where the secondary cold rolling reduction is 50 to 80% and the primary cold rolling reduction is 60% or less, the magnetic flux density is 1.6T.
As described above, when the secondary cold rolling reduction is 55% or more, 1.7 T
As described above, it was confirmed that a high value of 1.8 T or more was obtained around 70%.

Example 3 Using the same hot-rolled sheets as in Example 1, pickling these hot-rolled sheets to remove a surface oxide film, and then reducing the thickness to 0.8 mm (rolling ratio: 55.6%). Cold rolled (primary cold rolling). At 700 ° C 1
Annealing treatment was performed for 1 hour, 3 hours, and 1000 ° C. for 1 minute.

Next, with respect to the steel sheet after the primary annealing, a sheet thickness of 0.
After secondary cold rolling to 3 mm (rolling ratio: 62.5%), these steel sheets were subjected to a secondary annealing treatment at 1200 ° C. for 10 hours in a vacuum having an oxygen partial pressure of 0.5 Pa or less. .

At this stage, the direct current magnetic properties of the steel sheet were measured. Table 2 shows the results. As shown in Table 2, 7
00 having been subjected to the primary annealing at ℃ it was confirmed that good magnetic properties and B ₈ is 1.7T or higher is obtained.

Further, the above-mentioned steel sheet is subjected to tertiary cold rolling to 0.06 mm (rolling ratio: 80%) and 0.03 mm (rolling ratio: 90%), and then 1200 in a vacuum having an oxygen partial pressure of 0.5 Pa or less. A tertiary annealing treatment was performed at 1 ° C. for 1 hour, and the direct current magnetic properties of these steel sheets were measured. Table 3 shows the results.
Shown in Note that the sample numbers in Table 3 indicate the number of samples prepared under the same conditions. From these Tables 3, it was confirmed that, regardless of the condition of the primary annealing, by performing the tertiary rolling and the tertiary annealing under specific conditions, a steel material having an extremely high magnetic flux density can be obtained stably.

Example 4 The steel sheet obtained in Example 2 (except the one already cold-rolled to 0.1 mm) was tertiary cold-rolled to a sheet thickness of 0.1 mm (rolling ratio 30% or more). )
Then, in a vacuum with an oxygen partial pressure of 0.5 Pa or less, 10
An annealing treatment was performed at 50 ° C. for 1 hour, and the direct current magnetic properties of these steel sheets were measured. FIG. 4 shows the results.

As is clear from this figure, it was confirmed that all the steel sheets having a magnetic flux density of about 1.7 T or more (see FIG. 3) in the stage of Example 2 exhibited a high magnetic flux density of 1.9 T or more. Was done.

Example 5 Steels having the chemical components C1 to D3 shown in Table 4 were melted, and the finishing temperature: 800 ° C. and the winding temperature: 6
Hot rolling was performed under the conditions of 10 ° C. and a finished plate thickness of 1.8 mm. The hot-rolled sheet is pickled to remove a surface oxide film, and then subjected to primary cold rolling to a sheet thickness of 0.8 mm (rolling ratio: 55.6%). An annealing treatment was performed.

Next, with respect to the steel sheet after the primary annealing, the sheet thickness is set to 0.
Secondary cold rolling was performed to 3 mm (rolling ratio: 40%), and subsequently, these steel sheets were subjected to a secondary annealing treatment at 1180 ° C. for 10 hours in a hydrogen atmosphere having an oxygen partial pressure of 0.5 Pa or less. did. The B ₈ of steel sheets were measured using a DC magnetic measurement device. Table 5 shows the results. In addition, steel type C1
C3 is the result of changing the amount of Cu, and D1 to D3 are the results of changing the amount of Al. As is clear from Table 5, C
It was confirmed that a high magnetic flux density can be obtained when u and Al are 0.01 wt% or less.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

[Table 4]

[0056]

[Table 5]

[0057]

According to the present invention, there is provided a manufacturing method capable of manufacturing a grain-oriented silicon steel sheet having a crystal orientation integrated with a Goss orientation having excellent magnetic properties at a low manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a view showing DC magnetic characteristics of a steel sheet after primary annealing in Example 1.

FIG. 2 is a diagram showing DC magnetic characteristics of a steel sheet after secondary annealing in Example 1.

FIG. 3 is a view showing DC magnetic characteristics of a steel sheet obtained in Example 3.

FIG. 4 is a view showing DC magnetic characteristics of the steel sheet obtained in Example 4.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akira Hiraka 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Misao Namikawa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan (56) References JP-A-1-309924 (JP, A) JP-A-64-55339 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C21D 8 / 12

Claims (3)

(57) [Claims] 1. C: 0.01 wt% or less, Si: 2.5
To 7.0 wt%, S: 0.01 wt% or less, Al: 0. 0 wt%.
A steel material containing 01 wt% or less and N: 0.01 wt% or less is prepared, and after maintaining the steel material at 1000 ° C or more, hot rolling is performed so that the finishing temperature becomes 700 to 950 ° C.
Next, after performing a primary cold rolling of a rolling reduction of 40% or more,
Primary annealing at a temperature of 00 to 900 ° C.
0-80% secondary cold rolling is performed, and subsequently, in a reducing atmosphere or a non-oxidizing atmosphere with an oxygen partial pressure of 0.5 Pa or less, or in a vacuum with an oxygen partial pressure of 0.5 Pa or less.
A method for producing a grain-oriented silicon steel sheet having a crystal orientation integrated in a Goss orientation, characterized by performing secondary annealing at a temperature of 000 to 1300 ° C. 2. The steel according to claim 1, wherein the steel further contains 0.01 wt% or less of Cu.
A method for producing a grain-oriented silicon steel sheet having a crystal orientation integrated in a Goss orientation. 3. The steel material after the secondary annealing is further subjected to tertiary cold rolling at a rolling reduction of 30% or more, and subsequently a reducing atmosphere or a non-oxidizing atmosphere having an oxygen partial pressure of 0.5 Pa or less, or 3. The production of a grain-oriented silicon steel sheet having a crystal orientation integrated with Goss orientation according to claim 1 or 2, wherein the third annealing is performed at a temperature of 1000 to 1300 [deg.] C. in a vacuum having an oxygen partial pressure of 0.5 Pa or less. Method.