KR20160074350A - Oriented electrical steel sheet and method for manufacturing the same - Google Patents

Abstract

According to an embodiment of the present invention, the manufacturing method of the oriented electrical steel sheet comprises: a step of providing a slab including 1.0-4.0 wt% of silicon (Si), 0.1-0.4 wt% of carbon (C), 0.002-0.05 wt% of phosphorus (P), and iron (Fe) and unavoidable impurities; a step of heating the slab; a step of manufacturing a hot-rolled steel sheet by performing hot rolling of the slab; a step of performing annealing of hot-rolled sheets for the hot-rolled steel sheet; a step of performing cold rolling of the annealed hot-rolled steel sheet; a step of decarbonizing annealing the cold-rolled steel sheet; a step of performing cold rolling of the steel sheet for which decarbonizing annealing is completed; and a step of finally annealing the steel sheet for which cold rolling is completed. The slab comprises: 0.002 wt% or higher and 0.02 wt% or lower of antimony (Sb); 0.002 wt% or higher or lower than 0.03 wt% of tin (Sn); or a combination of the two. The present invention provides a manufacturing method of an oriented electrical steel sheet, and an oriented electrical steel sheet manufactured by the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a directional electric steel sheet,

To a directional electric steel sheet and a manufacturing method thereof.

The grain-oriented electrical steel sheet is a soft magnetic material having excellent magnetic properties in the rolling direction, consisting of crystal grains having a Goss orientation in which the crystal orientation of the steel sheet is {110} < 001 >.

The directional electrical steel sheet is rolled to a final thickness of usually 0.15 to 0.35 mm through hot rolling, hot-rolled sheet annealing, and cold rolling after the slab is heated, followed by high-temperature annealing for primary recrystallization annealing and secondary recrystallization.

At this time, it is known that, at a high temperature annealing, the degree of integration of the Goss orientation to be secondary recrystallized becomes higher as the temperature increase rate is slower, and the magnetism is excellent. In general, the rate of increase in temperature during high temperature annealing of a directional electric steel sheet is not more than 15 ° C per hour, and not only takes 2 to 3 days to raise the temperature, but also requires energy annealing more than 40 hours. In addition, since the current high-temperature annealing process is performed in a batch-type annealing in a coil state, the following difficulties arise in the process. First, a temperature deviation of the outer and inner windings of the coil occurs due to the heat treatment in the coil state, so that the same heat treatment pattern can not be applied to each part, resulting in magnetism deviation between the outer and inner windings. Second, since the MgO is coated on the surface after decarburization annealing and various surface defects are formed in the process of forming the base coating during the high temperature annealing, the rate of water drop is decreased. Third, since the decarburized annealed annealed decarburized plate is wound in a coil form, then annealed at high temperature, and then subjected to planarization annealing, the insulating coating is performed. Thus, the production process is divided into three stages, thereby causing a problem of a low yield rate.

In one embodiment of the present invention, a method for producing a directional electrical steel sheet and a directional electrical steel sheet produced by the method are provided.

A method for producing a grain-oriented electrical steel sheet according to an embodiment of the present invention comprises: 1.0 to 4.0% of Si, 0.1 to 0.4% of C, and 0.002 to 0.004% of P, based on 100% Providing a slab comprising 0.05% and the remainder comprising Fe and other inevitably incorporated impurities; Heating the slab; Hot-rolling the slab to produce a hot-rolled steel sheet; Annealing the hot-rolled steel sheet by hot-rolling; Cold-rolling the hot-rolled steel sheet annealed; Decarbonizing and annealing the cold-rolled steel sheet; Cold-rolling the steel sheet after completion of the decarburization annealing; And finally annealing the cold-rolled steel sheet; .

The slab may further contain Sn, Sb, or a combination thereof. The slab may be added in an amount of 0.002 wt% or more and 0.02 wt% or less, Sb alone, or 0.002 wt% or more and 0.03 wt% 0.002 wt% or more and 0.02 wt% or less of Sb and 0.002 wt% or more and 0.03 wt% or less of Sn, and the total amount of Sn and Sn to be added may be 0.04 wt% or less.

The step of final annealing after the cold rolling step may be continuous.

The step of decarburizing and annealing the cold-rolled steel sheet and the step of cold-rolling the decarburized annealed steel sheet may be repeated twice or more.

The reduction ratio in the cold rolling may be 50% to 70%.

The final annealing step is one which comprises a second stage performed at annealing temperature 850 ℃ to 1000 ℃ and dew point comprising: a first step of performing annealing at a temperature of 70 ℃ or less and 1000 ℃ to 1200 ℃ and H ₂ 50 vol% or more in the atmosphere .

The first step may be performed for 300 seconds or less, and the second step may be performed for 60 seconds to 300 seconds.

The heating temperature of the slab may be between 1100 ° C and 1350 ° C.

The grain-oriented electrical steel sheet according to an embodiment of the present invention has a ratio (D2 / D1) of the diameter (D1) of the circumscribed circle to the diameter (D2) of the inscribed circle in the goss grain is at least 0.5% And the crystal grain size in the range of 占 퐉 to 500 占 퐉 is 80% or more of the entire grains.

The grain-oriented electrical steel sheet may include Sn, Sb, or a combination thereof, and the balance includes Fe and other inevitably impurities. When Sb is added singly, the grain-oriented electrical steel sheet may contain 0.002 wt% or more of Sb 0.02 wt% or less; When Sn alone is added, 0.002 to 0.03% by weight of Sn is added; When both Sb and Sn are added, Sb is added in an amount of 0.002 to 0.02% by weight and Sn is added in an amount of 0.002 to 0.03% by weight, and the total amount of Sn and Sn to be added may be 0.04% by weight or less.

The directional electrical steel sheet may further comprise 1.0% to 4.0% Si and less than 0.002% C (not including 0%) in terms of% by weight.

According to one embodiment of the present invention, it is possible to provide a method of manufacturing a grain-oriented electrical steel sheet in which continuous annealing can be performed without annealing in a batch form in a coil state at the final annealing.

Further, it is possible to produce a grain-oriented electrical steel sheet with only a short time of annealing.

Unlike the conventional method for producing a grain-oriented electrical steel sheet, a step of winding a cold-rolled steel sheet is not required.

In addition, a method of manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention can provide a grain-oriented electrical steel sheet that does not use a grain growth inhibitor.

In addition, steep annealing can be omitted.

FIG. 1 is a photograph showing changes in texture through EBSD analysis of a directional electrical steel sheet during a final annealing process in a method of manufacturing a grain-oriented electrical steel sheet according to an embodiment.
FIG. 2 is a photograph showing crystal grain distribution of a grain oriented electrical steel sheet according to one embodiment of the present invention through EBSD analysis.
3 is a photograph showing the texture of a directional electric steel sheet produced by a final batch annealing process.
4 (a) is a photograph showing the grain distribution of the grain-oriented electrical steel sheet produced by Example 3 through EBSD analysis. 4 (b) is a photograph showing the grain distribution of the grain-oriented electrical steel sheet produced by the comparative example through EBSD analysis.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is intended that the disclosure of the present invention be limited only by the terms of the appended claims. Like reference numerals refer to like elements throughout the specification.

Thus, in some embodiments, well-known techniques are not specifically described to avoid an undesirable interpretation of the present invention. Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Whenever a component is referred to as "including" an element throughout the specification, it is to be understood that the element may include other elements, not the exclusion of any other element, unless the context clearly dictates otherwise. Also, singular forms include plural forms unless the context clearly dictates otherwise.

In addition, unless otherwise stated,% means weight%.

The method for manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention is characterized in that the slab is produced by firstly mixing 1.0% to 4.0% of Si, 0.1% to 0.4% of Si, 0.002% 0.05%, the remainder comprising Fe and other inevitably incorporated impurities and the remainder Fe and other inevitably incorporated impurities.

The slab further comprises Sn, Sb, or a combination thereof, and when Sb alone is added, Sb is added in an amount of not less than 0.002 wt% and not more than 0.02 wt%; When Sn alone is added, Sn is added in an amount of 0.002 wt% or more and 0.03 wt% or less; When both Sb and Sn are added, Sb is added in an amount of 0.002 wt% or more and 0.02 wt% or less, Sn is added in an amount of 0.002 wt% or more and 0.03 wt% or less, and the sum of Sn and Sn added is 0.04 wt% or less.

The reason for limiting the composition is as follows.

Si improves the iron loss by lowering the magnetic anisotropy of the electrical steel sheet and increasing the resistivity. When the Si content is less than 1.0%, the iron loss is inferior, and when the Si content is more than 4.0%, the brittleness is increased. Therefore, the content of Si in the grain-oriented electrical steel sheet after the slab and the final annealing step may be 1.0% to 4.0%.

C is required for the process of C to escape to the surface layer during the middle decarburization annealing and the final decarburization annealing so that the Goss crystal grains in the surface layer diffuse to the center portion, so the content of C in the slab may be 0.1 to 0.4%. Further, the amount of carbon in the grain-oriented electrical steel sheet after the final annealing step in which decarburization is completed may be 0.0020 wt% or less.

Sb is added in an amount of 0.002% or more, which is advantageous for nucleation of Goss grain during cold rolling. However, when 0.02% is exceeded, the surface is segregated and the decarburization rate is lowered, so that the Goss crystal grains formed in the surface layer may not be diffused into the inside.

Sn is added in an amount of 0.002% or more, so that a large amount of Goss grains can be generated in the surface layer by increasing the Goss grain nucleation site. However, if it is 0.03% or more, the decarburization rate is lowered and the Goss crystal grains formed in the surface layer may not be diffused into the inside.

If both of Sb and Sn are added, when the content exceeds 0.04 wt%, the decarburization rate is lowered, so that the Goss grains formed in the surface layer may not diffuse into the inside.

P is added in an amount of 0.002% or more to elongate the Goss nucleation site, but if it exceeds 0.05%, the rolling property may be deteriorated.

The slab having the above composition is heated. The slab heating temperature may be between 1100 ° C and 1350 ° C higher than the normal heating temperature.

When the slab is heated at a high temperature, there is a problem that the hot-rolled structure is coarsened and adversely affects magnetism. However, according to one embodiment of the present invention, since the content of carbon is larger than that in the related art, the hot-rolled steel sheet is not coarsened even when the slab heating temperature is as high as 1100 ° C to 1350 ° C, Which is advantageous in hot rolling.

The hot-rolled slab is hot-rolled to produce a hot-rolled steel sheet.

The hot-rolled steel sheet is subjected to hot-rolled sheet annealing. At this time, the hot-rolled sheet annealing can be carried out at an annealing temperature of 850 to 1000 占 폚. The dew point temperature may be 50 캜 to 70 캜.

Hot rolled steel sheet decarburization annealing is performed, pickling is carried out, and cold rolling is performed to produce a cold rolled steel sheet. The cold-rolled steel sheet is decarburized and annealed. Further, the steel sheet after the decarburization annealing is cold-rolled.

The step of decarburizing annealing the cold-rolled steel sheet and the step of cold-rolling the steel sheet after the decarburization annealing may be repeated two or more times.

The decarburization annealing process of the method for producing a grain-oriented electrical steel sheet according to one embodiment of the present invention will be described.

The decarburization annealing can be performed at a dew point temperature of 50 ° C to 70 ° C in a region where austenite single phase region or a composite phase of ferrite and austenite exist. At this time, the annealing temperature range may be 850 to 1000 캜. Further, the atmosphere may be a mixed gas atmosphere of hydrogen and nitrogen. The decarbonization amount in the decarburization annealing may be 0.0300 wt% to 0.0600 wt%.

In this decarburization annealing process, the grain size on the surface of the electric steel sheet grows to a great extent, but the crystal grains inside the electric steel sheet remain as a fine structure. After the decarburization annealing, the size of the surface ferrite grains may be 150 μm to 250 μm.

The cold rolling step of the method for producing a grain-oriented electrical steel sheet according to one embodiment of the present invention will be described.

It is known that it is effective to carry out cold rolling at a high pressure lowering rate which is close to 90% once in the manufacturing process of a conventional high magnetic flux density directional electric steel sheet. This is because only Goss crystal grains in the primary recrystallized grains create an environment favorable for grain growth.

However, according to one embodiment of the present invention, since the method for producing a grain-oriented electrical steel sheet internally diffuses Goss grain in the surface layer caused by decarburization annealing and cold rolling without using abnormal grain growth of Goss orientation grain, It is advantageous to form them so as to have a large distribution.

Therefore, when cold rolling is carried out at a reduction ratio of 50% to 70% in the cold rolling, many goss texture can be formed in the surface layer portion. Or 55% to 65%. Here, the reduction rate is (thickness of steel sheet before rolling-thickness of steel sheet after rolling) / (thickness of steel sheet before rolling).

In addition, a plurality of surface Goss texture structures can be formed in the surface layer at least twice in the decarburization annealing and cold rolling processes.

After the decarburization annealing and cold rolling have been completed, the steel sheet is subjected to final annealing.

In the method of manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention, unlike the conventional batch method, final annealing can be performed successively after cold rolling.

In the method for producing a grain-oriented electrical steel sheet according to an embodiment of the present invention, the final annealing step includes a first final annealing step in which annealing is performed at an annealing temperature of 850 ° C to 1050 ° C and a dew point temperature of 50 ° C to 70 ° C, And a second final annealing step performed in an atmosphere of 1200 캜 and H ₂ 50 vol% or more. Also, the atmosphere of the second final annealing step may be H ₂ Can be at least 90 vol%.

FIG. 1 is a photograph showing changes in texture through EBSD analysis of a directional electrical steel sheet during a final annealing process in a method of manufacturing a grain-oriented electrical steel sheet according to an embodiment. In FIG. 1, the red portion indicates a structure having a Goss orientation, and the texture changes progressively in (a) to (i).

The cold-rolled sheet before final annealing is in a state in which decarburization annealing proceeds so that the amount of carbon black remaining in the slab is 40 wt% to 60 wt% of the minimum amount of carbon in the slab. Therefore, at the first stage of the final annealing, the carbon grains are removed and the crystal grains formed in the surface layer are diffused inside. In the first step, decarburization can be carried out so that the amount of carbon in the steel sheet becomes 0.01 wt% or less.

Thereafter, in the second step, a texture having a Goss orientation diffused in the first step is grown. In the method for manufacturing a grain-oriented electrical steel sheet according to an embodiment of the present invention, unlike the case where the grains are grown by the conventional abnormal grain growth, the goss texture structure has a plurality of goss grain grains having a small grain size have.

The directional electrical steel sheet after completion of the final annealing can be dried after applying the insulating coating liquid as necessary.

According to one embodiment of the present invention, a directional electrical steel sheet as described below can be provided by the method for manufacturing a directional electrical steel sheet.

FIG. 2 is a photograph showing crystal grain distribution of a grain oriented electrical steel sheet according to one embodiment of the present invention through EBSD analysis.

2, the grain oriented electrical steel sheet according to an embodiment of the present invention is characterized in that the ratio (D2 / D1) of the diameter (D1) of the circumscribed circle and the diameter (D2) Of which 95% or more.

Here, the circumscribed circle means the smallest circle among the virtual circles surrounding the outside of the crystal grains, and the inscribed circle means the largest circle of the virtual circles included in the crystal grains.

Table 1 is a table showing the ratio (D2 / D1) of the relative size of the inscribed circle and the circumscribed circle of the grain-oriented electrical steel sheet according to one embodiment of the present invention shown in FIG.

Circumscribed circle D1 Inscribed circle (D2) The ratio (D2 / D1) 2.4 1.59 0.6625 2.54 1.5 0.590551181 2.7 2 0.740740741 1.7 1.1 0.647058824 1.9 1.2 0.631578947 2.5 1.3 0.52 2.2 1.2 0.545454545 2.9 1.7 0.586206897 2.2 1.4 0.636363636 1.9 1.1 0.578947368 1.3 0.9 0.692307692 1.8 1.2 0.666666667 1.2 0.7 0.583333333 1.7 1.1 0.647058824 1.8 One 0.555555556 1.7 0.9 0.529411765 1.2 0.8 0.666666667 1.3 0.9 0.692307692 2 One 0.5 1.5 0.8 0.533333333 1.2 0.7 0.583333333

Referring to Table 1, the grain-oriented electrical steel sheet according to an embodiment of the present invention has a ratio (D2 / D1) of the diameter (D1) of the circumscribed circle to the diameter (D2) 95% or more.

This is because the texture of the grain-oriented electrical steel sheet according to an embodiment of the present invention is such that the goth crystal grains on the surface grow into the steel sheet, and therefore, a round grain is produced.

Fig. 3 shows the texture of a directional electrical steel sheet produced by a final batch annealing process. It can be seen that the grain-oriented electrical steel sheet produced by the prior art produces grain ellipsoidal in shape longer than that of the grain oriented electrical steel sheet according to an embodiment of the present invention.

Table 2 shows the ratio (D2 / D1) of the relative size of the inscribed circle and the circumscribed circle of the grain-oriented electrical steel sheet shown in Fig.

Circumscribed circle D1 Inscribed circle (D2) The ratio (D2 / D1) 1.6 0.8 0.5 2.2 1.2 0.55 2.6 0.9 0.35 3.3 1.6 0.48 4.7 1.7 0.36 1.1 0.5 0.45 2.5 0.9 0.36 One 0.5 0.5 2.3 1.4 0.61 1.2 0.9 0.75 5.1 2.3 0.45 1.9 0.7 0.37 3.6 2.1 0.58 2.7 1.7 0.63 1.4 0.6 0.43 0.8 0.4 0.5 1.3 0.5 0.38 0.7 0.3 0.43 1.8 1.1 0.61 1.1 0.5 0.45 0.9 0.35 0.39

The directional electrical steel sheet produced by the prior art is a long elliptical type of grain, so that the value of D2 / D1 is smaller than that of the directional electrical steel sheet according to the embodiment of the present invention.

In addition, the grain size of the grain-oriented electrical steel sheet according to an embodiment of the present invention may be 80% or more of the total grains having a size of 20 탆 to 500 탆.

Hereinafter, the embodiment will be described in detail. The following examples are illustrative of the present invention only and are not intended to limit the scope of the present invention.

[Example 1]

2.0% Si and 0.20% C, Sb and Sn as shown in Table 3, and the balance Fe and unavoidable impurities. The slab was heated at a temperature of 1200 DEG C and hot-rolled to a thickness of 3 mm. Thereafter, the hot-rolled sheet was annealed at an annealing temperature of 870 캜 and a dew point temperature of 60 캜 for 150 seconds, cooled, and pickled. Thereafter, it was cold-rolled at a reduction ratio of 60%.

The cold-rolled sheet was subjected to decarburization annealing at an annealing temperature of 870 캜, a mixed gas atmosphere of hydrogen and nitrogen, and a dew point temperature of 60 캜.

Thereafter, the cold rolling was repeated three times. Here, the cold rolling process is repeated three times. That is, the hot-rolled sheet annealed is subjected to primary cold-rolling, primary decarburization annealing, secondary cold-rolling, secondary decarburization annealing and third cold- it means. The primary decarburization annealing is performed for 110 seconds and the secondary decarburization annealing is performed for 50 seconds.

Then, the steel sheet was subjected to first final annealing at a temperature of 950 占 폚, a mixed gas atmosphere of hydrogen and nitrogen at 60 占 폚 for 60 seconds, annealing temperature: 1050 占 폚, and a second Final annealing was performed. Table 3 shows the related contents.

Sb (% by weight) Sn (wt%) Goss fraction (%) B10 (T) W17 / 50 (W / Kg) Remarks 0 0 83 1.85 1.29 Comparative material 0.003 0 86 1.88 1.15 Invention material 0 0.003 85 1.87 1.17 Invention material 0.01 0 89 1.9 1.09 Invention material 0 0.01 89 1.89 1.19 Invention material 0.01 0.01 90 1.91 1.05 Invention material 0.02 0.02 89 1.89 1.14 Invention material 0.02 0.02 89 1.89 1.14 Invention material 0.02 0.03 69 1.75 1.78 Comparative material 0.03 0 75 1.78 1.67 Comparative material 0 0.04 77 1.75 1.8 Comparative material

As shown in Table 3, it can be seen that the Goss fraction is increased and the magnetic flux density and iron loss are superior at the addition of the appropriate amount of Sb and Sn. However, when excess Sb and Sn are added, the decarburization rate is lowered, and growth of the Goss grain of the surface layer is disturbed, and the magnetic property is drastically deteriorated.

[Example 2]

2.0% of Si and 0.20% of C in terms of% by weight, a slab containing P in Table 2, and the balance Fe and unavoidable impurities was prepared. The slab was heated to a temperature of 1200 DEG C and hot-rolled to a thickness of 3 mm. Then, hot-rolled sheet annealing was performed at an annealing temperature of 870 占 폚 and a dew point temperature of 60 占 폚 for 150 seconds, followed by cooling and pickling. And then cold rolled at a reduction ratio of 60%.

The cold-rolled sheet was subjected to decarburization annealing at an annealing temperature of 870 占 폚, a mixed gas atmosphere of hydrogen and nitrogen, and a dew point temperature of 60 占 폚.

Thereafter, the cold rolling was repeated three times. Here, the cold rolling process is repeated three times. That is, the hot-rolled sheet annealed is subjected to primary cold-rolling, primary decarburization annealing, secondary cold-rolling, secondary decarburization annealing and third cold- it means. The primary decarburization annealing is performed for 110 seconds and the secondary decarburization annealing is performed for 50 seconds.

Then, the steel sheet was subjected to first final annealing at a temperature of 950 占 폚, a mixed gas atmosphere of hydrogen and nitrogen at 60 占 폚 for 60 seconds, annealing temperature: 1050 占 폚, and a second Final annealing was performed. Table 4 shows the related contents.

P (% by weight) Crack occurrence Goss fraction (%) B10 (T) W17 / 50 (W / Kg) Remarks 0 X 83 1.85 1.29 Comparative material 0.01 X 86 1.89 1.21 Invention material 0.03 X 88 1.89 1.15 Invention material 0.05 X 88 1.9 1.2 Invention material 0.07 O - - - Comparative material 0.1 O - - - Comparative material

As shown in Table 4, when the P was added, the Goss fraction was increased, but the edge crack occurred.

[Example 3]

A slab containing 2.0% of Si, 0.20% of C, 0.0300% of P, 0.0100% of Sb and 0.0200% of Sn, and the balance Fe and unavoidable impurities was prepared. The slab was heated to a temperature of 1200 DEG C and hot-rolled to a thickness of 3 mm. Then, hot-rolled sheet annealing was performed at an annealing temperature of 870 占 폚 and a dew point temperature of 60 占 폚 for 150 seconds, followed by cooling and pickling. And then cold rolled at a reduction ratio of 60%.

The cold-rolled sheet was subjected to decarburization annealing at an annealing temperature of 870 占 폚, a mixed gas atmosphere of hydrogen and nitrogen, and a dew point temperature of 60 占 폚.

Thereafter, the cold rolling was repeated three times. Here, the cold rolling process is repeated three times. That is, the hot-rolled sheet annealed is subjected to primary cold-rolling, primary decarburization annealing, secondary cold-rolling, secondary decarburization annealing and third cold- it means. The primary decarburization annealing is performed for 110 seconds and the secondary decarburization annealing is performed for 50 seconds.

Then, the steel sheet was subjected to first final annealing at a temperature of 950 占 폚, a mixed gas atmosphere of hydrogen and nitrogen at 60 占 폚 for 60 seconds, annealing temperature: 1050 占 폚, and a second Final annealing was performed.

Further, the slab containing no Si, Sb and P was used as the slab containing 2.0% of Si and 0.20% of C and having the balance of Fe and unavoidable impurities. And made into a comparative material. 4 (a) is a photograph showing the grain distribution of the grain-oriented electrical steel sheet produced by Example 3 through EBSD analysis. 4 (b) is a photograph showing the grain distribution of the grain-oriented electrical steel sheet produced by the comparative example through EBSD analysis.

Referring to FIG. 4, it can be seen that the directional electrical steel sheet to which Sn, Sb and P are added has a finer grain size and more goth texture.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (10)

The steel slab includes 1.0 to 4.0% of Si, 0.1 to 0.4% of C, and 0.002 to 0.05% of P, based on 100% by weight of the total composition of the slab, the balance being Fe and other inevitably incorporated impurities Providing a slab comprising;
Heating the slab;
Hot-rolling the slab to produce a hot-rolled steel sheet;
Annealing the hot-rolled steel sheet by hot-rolling;
Cold-rolling the hot-rolled steel sheet annealed;
Decarbonizing and annealing the cold-rolled steel sheet;
Cold-rolling the steel sheet after completion of the decarburization annealing; And
Finally annealing the cold-rolled steel sheet; Wherein the method comprises the steps of:
Providing a slab comprising 1.0% to 4.0% of Si, and 0.1% to 0.4% of C, based on 100% by weight of the total composition of the slab, the balance comprising Fe and other inevitably incorporated impurities;
Heating the slab;
Hot-rolling the slab to produce a hot-rolled steel sheet;
Annealing the hot-rolled steel sheet by hot-rolling;
Cold-rolling the hot-rolled steel sheet annealed;
Decarbonizing and annealing the cold-rolled steel sheet;
Cold-rolling the steel sheet after completion of the decarburization annealing; And
Finally annealing the cold-rolled steel sheet; , &Lt; / RTI &
The slab further comprises Sn, Sb, or a combination thereof,
Sb alone or in an amount of not less than 0.002 wt% and not more than 0.02 wt%
0.002 wt% or more and 0.03 wt% or less of Sn,
A method for producing a grain-oriented electrical steel sheet wherein Sb and Sb are added in an amount of not less than 0.002 wt% and not more than 0.02 wt%, and Sn in an amount of not less than 0.002 wt% and not more than 0.03 wt%, wherein the sum of Sn and Sn added is 0.04 wt% .
3. The method of claim 2,
And the final annealing after the cold rolling is continued.
The method of claim 3,
Wherein the step of decarburizing and annealing the cold-rolled steel sheet and the step of cold-rolling the steel sheet after the decarburization annealing are repeated twice or more.
6. The method of claim 5,
Wherein the reduction ratio in the cold rolling is 50% to 70%.
6. The method of claim 5,
The finish-annealing step is a second finish-annealing step performed at annealing temperature 850 ℃ to 1000 ℃ and Like the first finish-annealing step, and 1000 ℃ to 1200 ℃ and H ₂ 50 vol% or more in an atmosphere to carry out annealing at a temperature of 70 ℃ below Wherein the method comprises the steps of:
The method according to claim 6,
Wherein the heating temperature of the slab is 1100 ° C to 1350 ° C.
The crystal grains in which the ratio (D2 / D1) of the diameter (D1) of the circumscribed circle to the diameter (D2) of the inscribed circle in the goss crystal grains is 0.5 or more is 95%
Wherein the grain size of 20 占 퐉 to 500 占 퐉 is 80% or more of the total grains.
9. The method of claim 8,
The directional electrical steel sheet comprises Sn, Sb, or a combination thereof, the balance comprising Fe and other inevitably incorporated impurities,
Sb alone or in an amount of not less than 0.002 wt% and not more than 0.02 wt%
0.002 wt% or more and 0.03 wt% or less of Sn,
0.002 wt% or more and 0.02 wt% or less of Sb and Sb and 0.002 wt% or more and 0.03 wt% or less of Sn, and the sum of Sn and Sn added is 0.04 wt% or less.
10. The method according to claim 8 or 9,
Wherein the grain-oriented electrical steel sheet further comprises 1.0% to 4.0% of Si, 0.1% to 0.4% of Si, and 0.002% to 0.05% of P by weight.

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