KR20150080241A - (１００)[０ｖｗ] ELECTRICAL STEEL SHEET CONTAINING HIGH Si AND ITS PRODUCTION METHOD - Google Patents

Abstract

The present invention relates to an electrical steel sheet containing high Si to be used for a steel core for electrical instruments such as motors and transformers and a production method thereof. According to an embodiment of the present invention, provided is a (100) [0vw] electrical steel sheet containing high Si, which is composed of C more than 0 wt% and equal to or less than 0.005 wt%, Si more than 4 wt% and equal to or less than 5 wt%, 0.05-1.0 wt% of Mn, 0.0001-0.035 wt% of S, Al more than 0 wt% and equal to or less than 0.20 wt%, P more than 0 wt% and equal to or less than 0.2 wt%, N more than 0 wt% and equal to or less than 0.005 wt%, a remaining amount of Fe, and impurities.

Description

(100) [0vw] electric steel sheet containing a large amount of Si and a method for producing the same [0001] The present invention relates to a (100)

The present invention relates to an electric steel sheet used as an iron core of an electric device such as a motor and a transformer and a method of manufacturing the same. More particularly, the present invention relates to a (100) [0vw] electric steel sheet containing a large amount of Si and a method of manufacturing the same.

In recent electric appliances, use in a high frequency range has been increasing for the purpose of high efficiency and miniaturization. In particular, as a generator for an electric automobile, improvement of magnetism in a high frequency range of 400 to 1,000 Hz is strongly demanded.

The non-oriented electrical steel sheet is an important component for converting electrical energy into mechanical energy in an electric device. In order to save energy, it is necessary to lower the iron loss and the magnetic flux density.

Iron loss is turned into heat in the process of energy conversion, and magnetic flux density appears as a force for generating power. Therefore, if the magnetic flux density is high, it is possible to reduce the mechanical loss of the electric device, thereby enabling miniaturization.

Iron loss may be lowered by lowering the thickness or by adding a large amount of alloying elements, but it may be produced as a pure steel having a low impurity content, or as a steel having an improved magnetic property by adding an additional element. In the case of the former, the costs for further processing in the manufacturing process are increased, and in the latter case, the costs for the additional elements are followed.

A method of producing a high-grade (111) [uvw] nonoriented electric steel sheet which is generally performed at present is characterized in that the main alloy contains about 3% of Si, 0.5 to 1.4% of Al, 0.1 to 0.4% of Mn, Inevitable impurities and residual components are obtained and good magnetic properties are obtained by lowering the slab heating temperature at the time of hot rolling. Specifically, as the slab heating temperature is low, such as 1050 to 1150 ° C, it is possible to obtain good magnetic properties. This is because, in order to prevent the generation of fine AlN and MnS which inhibits crystal growth during the final annealing by the winding-rewinding method, a method of reheating the slab at a low temperature is the only method.

Eddy current loss (P _ec ) of electric steel sheet is expressed by the following equation.

Where Bo is the magnetic flux density, t is the thickness of the steel plate, f is the frequency, and p is the resistivity. Thus, when all conditions are fixed, increasing the resistivity decreases the eddy current loss (P _ec ).

At this time, the effect of increasing the resistivity depending on the amount of the additive element is shown in Fig.

1, the effect of increasing the resistivity of silicon (Si) is the largest, and the resistivity effect of aluminum (Al) is also similar to that of silicon.

However, in the case of increasing the silicon content to increase the resistivity, the cold workability due to the reduction in elongation rate sharply decreases, and when the silicon content exceeds 3.5%, it is known that cold rolling can not be industrially carried out. 3%.

1, when the amount of silicon in the electrical steel sheet is increased from 3% to 5%, the eddy loss is reduced to about half of that before the increase of the silicon content. Therefore, in order to improve the magnetic properties, Is contained in an amount exceeding 4%, and at the same time, it is necessary to develop an electric steel sheet excellent in cold workability.

Recently, it has been reported that (100) [0vw] crystal orientations can be obtained in an electric steel sheet containing 2 to 4% Si in the registered patent 10-1203791 (Patent document 1) and the patent document 10-1227767 (Patent document 2).

Fig. 2 shows the ideal crystal orientation and each crystal orientation obtained by the Etch-pit method.

Research has been published on the development of (100) [0vw] electrical steel sheet superior in magnetic properties to conventional (111) [uvw] nonoriented electrical steel sheets. In the research results such as T. Tomida (see Non-Patent Documents 1 and 2) and Patent Application No. 10-0797895 (Patent Document 3), S is treated as an inevitable impurity, and a steel sheet containing a large amount of C is subjected to isothermal heat treatment in vacuum (100) [0vw] crystal orientation while a phase transformation from austenite (?) To ferrite (?) Takes place by decarburization reaction, and a method of obtaining a large amount of Mn-containing steel sheet from austenite (100) [0 vw] crystal orientation using phase transformation to ferrite (?).

However, in the above-described (100) [0vw] nonoriented electrical steel sheet making methods, commercialization has failed due to a difficult vacuum heat treatment method and a long heat treatment time of several tens of hours.

KR 10-1203791 B1 (2012.11.21 Announcement) KR 10-1227767 B1 (2013.01.29 Announcement) KR 10-0797895 B1 (2008.01.24 Announcement)

 IEEE Trans. Magnetics vol. 37, 2001, pp 2318  J. Magnetism and Magnetic Materials vol. 254-255, 2003, pp 315

In order to significantly reduce the iron loss in the production of the (100) [0vw] electrical steel sheet, the Si content is increased to 4 to 5% by weight, which is higher than the existing value, and S is added as the most important element, A large amount of Si that can be produced by a heat treatment at a low cost and a short time by using a winding-rewinding method in a reductive gas atmosphere instead of a vacuum in the final annealing by using a steel sheet having the compositional composition showing the ferrite structure There is a main purpose in providing one (100) [0vw] electrical steel sheet and its manufacturing method.

According to a preferred embodiment of the present invention, there is provided a ferritic stainless steel comprising, by weight, C: more than 0 to 0.005%, Si: more than 4 to 5%, Mn: 0.05 to 1.0%, S: 0.0001 to 0.035% (100) [0vw] electrical steel sheet containing a large amount of Si, which contains not more than 0.1% by mass of P, not less than 0% and not more than 0.2%, N: more than 0 and not more than 0.005%, and the balance of Fe and other unavoidable impurities.

The electrical steel sheet is one-stage annealed in a one-stage annealing furnace at 800 ° C to 1090 ° C, and is characterized in that it is two-stage annealed in a two-stage annealing furnace at 1100 ° C to 1350 ° C.

In this case, it is preferable that the heat treatment time in the one-stage annealing furnace is 10 seconds to 600 seconds, and the heat treatment time in the two-stage annealing furnace is 10 seconds to 600 seconds.

Further, it is preferable that the S content is more than 0.008% and 0.035% or less.

On the other hand, when the content of C is more than 0% and not more than 0.005%, the content of Si is more than 4%, the content of Mn is 0.05% to 1.0%, the content of S is 0.0001 to 0.035% %, N: not less than 0 and not more than 0.005%, and the remaining Fe and other unavoidable impurities are hot-rolled and pickled and cold-rolled, and the cold-rolled steel sheet is subjected to a first stage annealing at 800 ° C to 1090 ° C (100) [0vw] electrical steel sheet containing a large amount of Si, which is characterized in that it is annealed and annealed in two stages in a two-stage annealing furnace at 1100 ° C to 1350 ° C.

In this case, it is preferable that the heat treatment time in the one-stage annealing furnace is 10 seconds to 600 seconds, and the heat treatment time in the two-stage annealing furnace is 10 seconds to 600 seconds.

Further, after the slab is reheated and hot-rolled, the hot-rolled sheet may be subjected to intermediate annealing in a temperature range of 650 ° C to 1100 ° C, or may be cold rolled after pickling and pickling.

At this time, the annealed plate structure subjected to the slab structure and final annealing represents a ferrite phase structure.

Compared with the (100) [0vw] electrical steel sheet produced by the conventional method of heat-treating in vacuum for a long time by using a steel sheet containing a large amount of C and Mn for phase transformation from austenite (γ) to ferrite (α) The (100) [0vw] electric steel sheet containing a large amount of Si according to the preferred embodiment of the present invention is heat treated in a reductive gas atmosphere instead of a vacuum using a steel sheet showing a ferrite structure at a preheating temperature range, (100) [0vw] crystal orientation is formed inexpensively.

Therefore, it is possible to manufacture an electric steel sheet by a winding-rewinding method, and it is possible to improve productivity and reduce manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the resistivity increasing effect according to the amount of additive in an electrical steel sheet.
Fig. 2 is a diagram showing the ideal crystal orientation and each crystal orientation obtained by the Etch-pit method. Fig.
Fig. 3 is a photograph of an etch rate showing the crystal orientation distribution of the steel material A according to Example 2. Fig.
Fig. 4 is a photograph showing a fracture profile of a tensile specimen before and after the middle annealing of the hot-rolled sheet.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of a (100) [0vw] electrical steel sheet containing a large amount of Si according to the present invention and a method for producing the same will be described with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

In addition, the following embodiments are not intended to limit the scope of the present invention, but merely as exemplifications of the constituent elements set forth in the claims of the present invention, and are included in technical ideas throughout the specification of the present invention, Embodiments that include components replaceable as equivalents in the elements may be included within the scope of the present invention.

The present invention relates to a method for producing a (100) [0vw] electrical steel sheet containing a high Si content by adding 0.0001% to 0.035% of S, which is the most important element in terms of% by weight, It is preferable that the amount of Al which interferes with the surface energy organic selective crystal growth of the (100) crystal grains due to surface segregated S is controlled to exceed 0.20% by weight on the premise of the ferrite phase in the entire temperature range of the manufacturing process, N exceeding 0 to 0.005 wt%, and P exceeding 0 to 0.2 wt%.

Accordingly, the content range of the slab used in the present invention is in the range of C: more than 0% to 0.005%, Si: more than 4%, Mn: 0.05% % To 1.0%, S: 0.0001 to 0.035%, Al: more than 0 to 0.20%, P: more than 0 to 0.2%, N: more than 0 to 0.003%, and the balance of Fe and other unavoidable impurities. As a result, a (100) [0vw] electrical steel sheet excellent in magnetic properties within the component range can be manufactured easily and inexpensively.

With respect to the addition amount of the alloy element to be mixed, the increase in the resistivity is the largest at Si and the effect of Mn at about half of Si.

In addition, one embodiment of the present invention is a steel sheet comprising: C: more than 0% to 0.005%, Si: more than 4%, Mn: 0.05% to 1.0%, S: 0.0001 to 0.035% By mass or less, P: more than 0 and not more than 0.2%, N: more than 0 and not more than 0.005%, and the balance Fe and other unavoidable impurities, After the intermediate annealing at 1100 ° C, pickling and cold rolling, the heat treatment atmosphere for the single-stage annealing furnace and the two-stage annealing furnace is such that the reducing gas (100) And the surface of the annealed plate is made of (100) [0 vw] crystal orientation.

In this case, in order to maximally activate (100) crystal growth at the two-stage annealing temperature higher than the first-stage annealing temperature while suppressing the (111) crystal growth at the first annealing, the temperature of the first annealing furnace is preferably 800 to 1090 ° C, and the temperature of the two-stage annealing furnace is set to 1100 ° C to 1350 ° C higher than the one-stage annealing furnace temperature.

Hereinafter, reasons for limiting the composition of the present invention will be described.

S: 0.0001 to 0.035% by weight

As described above, since the selective crystal growth of the desired (100) [0 vw] crystal grains can occur when an appropriate amount of surface segregated S exists, the surface energy of (110) (110) [uvw] crystal orientation is obtained instead of the (100) [0vw] crystal orientation finally because only the (110) crystal grains grow while encroaching the other crystal grains.

Therefore, the substantial S content should be at least 0.0001 wt% or more so that S can be surface segregated to change the surface energy, and prevent the formation of MnS that interferes with the selective crystal growth of (100) [0vw] If possible, S is preferably limited to 0.035% by weight or less.

More preferably, in consideration of economical efficiency in the current steelmaking process, S is preferably limited to 0.008 wt% or more and 0.035 wt% or less.

C: more than 0 and not more than 0.005% by weight

In the conventional (100) [0vw] crystal orientation forming method using the austenite (?) Ferrite (?) Phase transformation accompanied by the decarburization reaction occurring in the long-time vacuum heat treatment, 0.02 to 0.07% of C is necessarily included in the steel sheet .

In this case, due to the extremely slow decarburization reaction in vacuum, a heat treatment time of several tens of hours is required until a (100) [0 vw] crystal orientation is obtained after final annealing, and a batch type heat treatment suitable for a long heat treatment time is inevitable.

However, in the case of the (100) [0vw] non-oriented electrical steel sheet manufacturing method according to an embodiment of the present invention, the conventional long-time oxidative vacuum atmosphere heat treatment method using the conventional austenite? Ferrite , As shown in Table 1 of the following examples, the composition showing the ferrite structure in the entire temperature range of the normal temperature of the manufacturing process is used, and in order to obtain the (100) [0vw] crystal orientation easily after the final annealing in a short time in the reducing gas atmosphere, To less than 0.005% by weight of C, which is a strong austenite stabilizing element in the range.

Accordingly, in the case of the (100) [0vw] nonoriented electrical steel sheet manufacturing method according to an embodiment of the present invention, the conventional (111) [uvw] unoriented electric steel sheet production method, Winding-rewinding method, it is possible to mass-produce in a short period of time, and it is possible to reduce the manufacturing cost by improving the productivity.

On the other hand, Ti, B, Sn, Sb, Ca, Zr, Nb, V, Cu and the like are examples of impurities which are inevitably added as impurities.

Si: more than 4 and not more than 5.0%

Si is added because it increases the resistivity and lowers the eddy loss in the iron loss. If the Si content is less than 4 wt%, the electrical resistivity is small and the eddy current loss becomes large. Therefore, the Si content is preferably more than 4 wt%.

If the content exceeds 5.0% by weight, even if the steel sheet is subjected to the intermediate annealing, the cold rolled steel sheet is broken and the rolled sheet is broken, so that the composition of the normal steel slab is 4.0 wt% % To 5.0% by weight.

Mn: 0.05 to 1.0 wt%

Mn is an austenite stabilizing element such as Si, which increases the specific resistance and lowers the eddy loss in the iron loss. If Mn is added in an amount of 1.0 weight% or more, however, the cold rolled steel tends to be broken and the cold rolled steel tends to break.

Therefore, in order to obtain an electric steel sheet having a desired (100) [0vw] crystal orientation by using the manufacturing method of the present invention, the slab can exhibit a ferrite structure in the temperature range over the entire manufacturing process, , It is desirable to limit the content of Mn to 0.05% to 1.0%, which is the minimum amount that can be lowered in the present steelmaking process.

Al: more than 0 and not more than 0.2% by weight

Al is an effective component to lower the eddy loss by increasing the resistivity like Si. Therefore, it is added to the existing (111) [uvw] nonoriented electric steel sheet by 0.2 ~ 1.3%.

However, since the object of the present invention is to produce a (100) [0vw] nonoriented electrical steel sheet, when Al is added in an amount of more than 0.2% in the composition of the present invention, a surface oxidation layer of Al is formed during annealing, The H ₂ S reaction which is the reaction between S segregated on the surface of the steel sheet and the hydrogen in the reducing atmosphere does not occur smoothly due to the surface oxide layer and thus the segregation concentration of S on the surface of the steel sheet immediately below the surface oxide layer is increased.

As a result, the surface energy of (111) crystal grains is minimized rather than the surface energy of (100) crystal grains. Accordingly, as Al increases, selective crystal growth of (111) crystal grains is promoted rather than selective crystal growth of (100) crystal grains so that the final crystal orientation is (111) [uvw ] Crystal orientation, it is preferable to limit the Al content to more than 0 to 0.2% by weight in order to obtain the (100) [0vw] crystal orientation.

P: more than 0 and not more than 0.2% by weight

P is added because it increases the resistivity to lower the iron loss, and the result of Example 10 below shows that addition of 0.1 wt% does not affect the obtaining of the complete (100) [0 vw] crystal orientation. However, if P is added excessively, there is a high possibility of cracking during cold rolling due to crystal grain embrittlement due to grain boundary segregation of P during the hot rolling process, so that it is preferable to limit the amount to more than 0 to 0.2 wt%.

N: more than 0 and not more than 0.005% by weight

In order to prevent the selective crystal growth inhibition of the (100) [0vw] crystal grains by the produced AlN, it is preferable to reduce N to 0 to 0.005 wt% or less, if possible.

Hereinafter, a method for producing a (100) [0vw] electrical steel sheet containing a large amount of Si according to an embodiment of the present invention will be described.

Since the slab is heated to a high temperature of 1200 DEG C or more and the fusing temperature in the hot rolling process is 900 DEG C or more, hot rolling does not adversely affect the crystal growth in the final annealing since there is little precipitation of AlN and MnS on the hot- Do not. Further, in the case where the hot-rolled sheet is annealed in the same component and in the case where the hot-rolled sheet is not annealed, magnetic characteristics of the same level can be obtained.

According to one embodiment of the present invention, the hot-rolled sheet may be subjected to intermediate annealing in the range of 650 ° C. to 1100 ° C., It is also possible to perform the cold rolling two times including annealing.

As described above, the final annealing composed of the first stage and the second stage is preferably performed in a reducing gas atmosphere containing hydrogen and / or nitrogen in order to prevent (111) crystal growth due to surface oxidation of Al, Fe, Si and the like .

In order to obtain a stable (100) [0 vw] crystal orientation in the two-stage annealing, the one-stage annealing and the two-stage annealing should be divided into a one-stage annealing and a two- So that the continuous annealing can be performed.

At this time, in order to maximize the crystal growth of (100) at the two-stage annealing temperature higher than the first-stage annealing temperature while suppressing the (111) crystal growth at the first annealing, the temperature and heat treatment time range of the first annealing furnace 800 to 1090 占 폚, and 10 seconds to 600 seconds, and the temperature and the heat treatment time range of the two-stage annealing furnace are 1100 占 폚 to 1350 占 폚 and 10 seconds to 600 seconds.

When the annealing time is less than 10 seconds, the atom movement time is not sufficient and the annealing time is changed from (100) to (111) 600 seconds.

The (100) [0vw] electric steel sheet containing a large amount of Si according to an embodiment of the present invention can be continuously produced using the winding-rewinding method from the above-described hot rolling to the final annealing .

On the other hand, the surface coating of the produced electrical steel sheet may be carried out by a coating method which is usually used if necessary.

Hereinafter, examples will be described.

Table 1 shows various chemical compositions of the specimens to be used in Examples to be described later, and the remainder consists of Fe and other inevitable impurities. Table 2 shows heat treatment conditions related to intermediate annealing conditions and final annealing conditions.

Each of the specimens was in the form of a plate, and the plates were cast into an ingot through a vacuum induction melting process. The ingot was hot-rolled at 1150 ° C and hot-rolled to a temperature of 650 ° C to 1100 ° C , And cold rolled after pickling to prepare a cold-rolled steel sheet having a thickness of 0.35 mm.

The final annealing method for the cold-rolled steel sheet is not a vacuum but a one-stage annealing and a two-stage annealing performed in a reducing gas atmosphere.

In this case, in the case of the heat treatment including the one-stage annealing and the two-stage annealing, the temperature and the heat treatment time range of the one-stage annealing furnace are 850 to 1090 ° C and 10 seconds to 600 seconds, 1100 ° C to 1350 ° C and 10 seconds to 600 seconds.

An etch-pit method and an optical microscope were used to determine the crystal orientation of the annealed sheet.

Steel grade
Component (% by weight) C Si Mn P S Al N A 0.002 4.1 0.1 0.004 0.001 0.0008 0.001 B 0.002 4.0 0.1 0.004 0.001 0.2 0.001 C 0.002 4.1 0.1 0.003 0.03 0.0008 0.002 D 0.002 4.1 0.1 0.1 0.001 0.0005 0.001 E 0.002 4.4 1.0 0.004 0.001 0.0006 0.002 F 0.002 4.6 0.1 0.004 0.002 0.0005 0.001 G 0.002 5.0 0.1 0.005 0.003 0.0005 0.001

Example

Steel grade
Intermediate annealing condition
Final Annealing Conditions Crystal orientation fraction
x%: (100) [0vw]
y%: (111) [uvw] Single-stage annealing Two-step annealing Temperature
(° C) time
(sec) Temperature
(° C) time
(sec) Temperature
(° C) time
(sec) x
(%) y
(%) Example 1 A-0 670 120 skip skip 1300 20 56 44 Example 2 A-1 670 120 850 600 1300 20 100 0 Example 3 A-2 1100 60 1080 7 1300 210 100 0 Example 4 A-3 skip skip 900 90 1250 210 100 0 Example 5 A-4 skip skip 960 30 1200 210 100 0 Example 6 A-5 skip skip 1000 15 1150 210 100 0 Example 7 A-6 skip skip 1020 10 1150 210 100 0 Example 8 B skip skip 1050 10 1200 210 35 65 Example 9 C skip skip 1050 30 1200 300 100 0 Example 10 D skip skip 1000 30 1150 210 100 0 Example 11 E 1050 60 1050 10 1150 210 100 0 Example 12 F 1050 60 900 90 1150 600 100 0 Example 13 G 670 120 1080 7 1100 410 100 0

[Example 1]

A hot-rolled sheet formed as shown in A of Table 1 was subjected to an intermediate annealing treatment at 670 캜 as shown in A-0 of Table 2, followed by pickling and cold rolling to prepare a cold-rolled steel sheet having a thickness of 0.35 mm. In the test, the single-stage annealing was omitted and the two-stage annealing was performed at 1300 ° C for 20 seconds. Table 2 shows the associated crystal orientation fractions, showing electrical steel sheet texture of 56% (100) [0vw] and 44% (111) [uvw]. This is a result of the (100) crystal growth being not sufficiently achieved by omitting one-stage annealing.

[Example 2]

The hot-rolled sheet formed as shown in A of Table 1 was subjected to an intermediate annealing treatment at 670 캜 as shown in A-1 of Table 2, followed by pickling and cold rolling to produce a cold-rolled steel sheet having a thickness of 0.35 mm. In the test, one step annealing was performed at 850 ° C for 600 seconds, and then the two-step annealing was performed at 1300 ° C for 20 seconds. FIG. 3, which shows Table 2 and the Atchip type, shows a 100% (100) [0vw] electrical steel sheet texture.

[Example 3]

A hot-rolled steel sheet having a composition as shown in A of Table 1 was subjected to intermediate annealing at 1100 ° C as shown in A-2 of Table 2, followed by pickling and cold rolling to prepare cold-rolled steel sheets having a thickness of 0.35 mm. In the test, one step of annealing was performed at 1080 ° C for 7 seconds, followed by a two-step annealing at 1300 ° C for 210 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

[Example 4]

A cold-rolled steel sheet having a thickness of 0.35 mm was produced by pickling and cold rolling without intermediate annealing as shown in A-3 of Table 2 above, and the hot- , Followed by one-step annealing at 900 DEG C for 90 seconds and then two-step annealing at 1250 DEG C for 210 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

[Example 5]

A cold rolled steel sheet having a thickness of 0.35 mm was produced by pickling and cold rolling without intermediate annealing as shown in A-4 of Table 2 above, and the cold rolled steel sheet was subjected to final annealing , Followed by one-step annealing at 960 占 폚 for 30 seconds, followed by two-step annealing at 1200 占 폚 for 210 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

[Example 6]

A hot-rolled steel sheet having a thickness of 0.35 mm was produced by pickling and cold rolling without intermediate annealing as shown in A-5 of Table 2 above, and the cold-rolled steel sheet was subjected to final annealing , Followed by one-step annealing at 1000 캜 for 15 seconds, followed by two-step annealing at 1150 캜 for 210 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

[Example 7]

A cold rolled steel sheet having a thickness of 0.35 mm was produced by pickling and cold rolling without intermediate annealing as shown in A-6 of Table 2 above, , Followed by one-stage annealing at 1020 占 폚 for 10 seconds, followed by two-stage annealing at 1150 占 폚 for 210 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

[Example 8]

A hot-rolled steel sheet having a thickness of 0.35 mm was produced by pickling and cold rolling without intermediate annealing as shown in Table 2 B of Table 1, and the steel sheet was subjected to final annealing at 1050 Lt; 0 > C for 10 seconds, followed by two-stage annealing at 1200 DEG C for 210 seconds. Table 2 shows the electrical steel sheet structure of 35% (100) [0vw] and 65% (111) [uvw] in the final annealing crystal orientation. This is because as the Al increases, the selective crystal growth of the (111) crystal grains is promoted rather than the selective crystal growth of the (100) crystal grains, so that the final crystal orientation shifts from (100) (111) [uvw] crystal orientation.

[Example 9]

A cold rolled steel sheet having a thickness of 0.35 mm was prepared by pickling and cold rolling without intermediate annealing as shown in C of Table 2 above, and a hot rolled steel sheet having a thickness of 1050 Lt; 0 > C for 30 seconds, followed by two-stage annealing at 1200 < 0 > C for 300 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

[Example 10]

A cold-rolled steel sheet having a thickness of 0.35 mm was prepared by pickling and cold rolling without intermediate annealing as shown in D of Table 2, as shown in D of Table 1 above. When the cold-rolled steel sheet was subjected to final annealing, 1000 Lt; 0 > C for 30 seconds, followed by two-stage annealing at 1150 [deg.] C for 210 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

[Example 11]

The hot-rolled sheet as shown in E of Table 1 was subjected to intermediate annealing at 1050 ° C as shown in E of Table 2, followed by pickling and cold rolling to obtain a cold-rolled steel sheet having a thickness of 0.35 mm. , Followed by one-step annealing at 1050 캜 for 10 seconds, followed by two-step annealing at 1150 캜 for 210 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

[Example 12]

The hot-rolled sheet formed as shown in F of Table 1 was subjected to intermediate annealing at 1050 ° C as shown in F of Table 2, followed by pickling and cold rolling to produce a cold-rolled steel sheet having a thickness of 0.35 mm. , Followed by one-step annealing at 900 ° C for 90 seconds and then two-step annealing at 1150 ° C for 600 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

 [Example 13]

The hot-rolled steel sheets as shown in G of Table 1 were subjected to an intermediate annealing treatment at 670 ° C as shown in Table 2, followed by pickling and cold rolling to produce cold-rolled steel sheets having a thickness of 0.35 mm. , Followed by one-step annealing at 1080 占 폚 for 7 seconds, followed by two-step annealing at 1100 占 폚 for 400 seconds. Table 2 shows the 100% (100) [0 vw] electrical steel sheet texture of the final annealing crystal orientation.

On the other hand, in Examples 4 to 10, cold rolling could be carried out without plate breakage even when intermediate annealing was not performed when the Si content exceeded 3.5%, unlike the conventionally known. Therefore, intermediate annealing is not a necessary condition for cold rolling in these embodiments.

However, in the case of Examples 11 to 13 for steel types containing a higher Si content, cold rolling was difficult due to sheet breakage unless proper intermediate annealing was performed. Therefore, in order to prevent unexpected plate fracture at the time of cold rolling and to make cold rolling more stable, it is preferable to perform appropriate intermediate annealing for the hot rolled steel sheet before cold rolling with respect to the steel of the entire composition range of the present invention.

Fig. 4 is a photograph showing the fracture appearance of the tensile test specimen before and after the intermediate annealing of the hot-rolled steel sheet in Examples 11 to 13. Fig.

The hot-rolled steel sheet in which the intermediate annealing is omitted shows typical brittle fracture with low elongation (Fig. 4 (a)) and cold rolling is impossible. It can be seen that cold rolling is possible.

Claims (8)

C: more than 0% to 0.005%, Si: more than 4%, Mn: 0.05% to 1.0%, S: 0.0001 to 0.035%, Al: more than 0.20% , N: not less than 0 and not more than 0.005%, and a large amount of Si constituted by remaining Fe and other unavoidable impurities.
The method according to claim 1,
(100) [0vw] electrical steel sheet containing a large amount of Si, characterized in that it is annealed in a single stage annealing furnace at 800 ° C to 1090 ° C and annealed twice in a two-stage annealing furnace at 1100 ° C to 1350 ° C.
The method of claim 2,
(100) [0vw] electric steel sheet containing a large amount of Si, characterized in that the heat treatment time in the one-stage annealing furnace is 10 seconds to 600 seconds and the heat treatment time in the two-stage annealing furnace is 10 seconds to 600 seconds.
The method according to claim 1,
(100) [0vw] electrical steel sheet containing a large amount of Si, characterized in that S is contained in an amount of more than 0.008% to 0.035% or less.
C: more than 0% to 0.005%, Si: more than 4%, Mn: 0.05% to 1.0%, S: 0.0001 to 0.035%, Al: more than 0.20% , N: not less than 0 and not more than 0.005%, and the remaining Fe and other unavoidable impurities are hot-rolled, pickled and cold-rolled, and the cold-rolled steel sheet is subjected to one-stage annealing at a temperature of 800 ° C to 1090 ° C (100) [0vw] electric steel sheet containing a large amount of Si, characterized in that the two-stage annealing is performed in a two-stage annealing furnace at 1100 ° C to 1350 ° C.
The method of claim 5,
(100) [0vw] electric steel sheet containing a large amount of Si, characterized in that the heat treatment time in the one-stage annealing furnace is 10 seconds to 600 seconds and the heat treatment time in the two-stage annealing furnace is 10 seconds to 600 seconds Gt;
The method of claim 5,
(100) [0vw] electric steel sheet containing a large amount of Si, characterized in that the slab is reheated and hot-rolled and thereafter subjected to intermediate annealing of the hot-rolled sheet in the temperature range of 650 ° C to 1100 ° C, ≪ / RTI >
The method of claim 5,
(100) [0vw] electric steel sheet containing a large amount of Si, characterized in that the slab structure and the annealed plate structure subjected to final annealing are ferrite-like structures.

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