JP2019116680A - Slab for grain-oriented electrical steel sheet, grain-oriented electrical steel sheet and manufacturing method thereof - Google Patents

Abstract

To provide a grain-oriented electrical steel sheet and a manufacturing method of the grain-oriented electrical steel sheet.SOLUTION: The manufacturing method includes: a step of heating a slab that contains, by mass%, Si: 3.0 to 5.0%, C: 0.01 to 0.15%, Mn: 0.1 to 1.5%, with the balance containing Fe and other unavoidable impurities, and satisfies following formulas 1 and 2; a step of hot rolling the slab to produce a hot rolled sheet; a step of cold rolling the hot rolled sheet to produce a cold rolled sheet; a step of primary recrystallization annealing of the cold rolled sheet; and a step of secondary recrystallization annealing of the cold-rolled sheet on which the primary recrystallization annealing has been completed. Formula 1:0.5≤[Si]/(100×[C]×[Mn])≤3, Formula 2:(0.04×[Si]-0.075)-(0.045×[Mn])≤[C]≤(0.055×[Si] -0.1)-(0.055×[Mn]). [Si], [C], and [Mn] in Formula 1 and Formula 2 indicate a content (mass%) of Si, C, and Mn, respectively.SELECTED DRAWING: None

Description

  The present invention relates to a slab for a directional electrical steel sheet, a directional electrical steel sheet, and a method of manufacturing the same, and more specifically, by precisely adjusting the contents of Mn and C according to the content of Si in the slab, The present invention relates to a slab for a directional magnetic steel sheet for obtaining excellent magnetism, a directional magnetic steel sheet, and a method of manufacturing the directional magnetic steel sheet.

The grain-oriented electrical steel sheet forms a so-called goss texture in which the crystal grain orientation of the steel sheet surface is {110} and the crystal orientation in the rolling direction is parallel to the <001> axis, It is a soft magnetic material whose magnetic properties are increased in the rolling direction of the steel sheet. In general, whether or not the magnetic properties are excellent is expressed by magnetic flux density and core loss, and high magnetic flux density can be obtained by correctly arranging the orientation of crystal grains in the {110} <001> orientation. The electromagnetic steel sheet having a high magnetic flux density not only can reduce the size of the core material of the electric device, but also the hysteresis loss can be reduced to achieve the miniaturization of the electric device and the high efficiency. Iron loss is a power loss consumed as thermal energy when an arbitrary alternating magnetic field is applied to a steel plate, and the higher the magnetic flux density and specific resistance, and the lower the thickness and the amount of impurities in the steel plate, Iron loss decreases and the efficiency of electrical devices increases.
Currently, in order to reduce CO ₂ emissions worldwide and respond to global warming, we are aiming to commercialize products with high efficiency and energy efficiency, and use highly efficient electrical equipment that uses less electrical energy With the increasing demand for the spread of the steel, the social demand for the development of a directional electrical steel sheet having better low iron loss characteristics is increasing.

  In a grain-oriented electrical steel sheet excellent in magnetic properties, Goss texture consisting of crystal grains having an orientation within 15 ° from the {110} <001> orientation in the rolling direction of the steel sheet must be strongly developed, In order to form such texture, Goth-oriented crystal grains must form special grain growth called secondary recrystallization. Such special crystal growth is different from normal crystal grain growth, and the movement of the crystal grain boundary, which is usually grown by precipitates, inclusions, or elements that segregate in solid solution or grain boundaries, is suppressed. Occurs when the The precipitates and inclusions that suppress grain growth in this way are referred to as grain growth inhibitors, in particular, and the manufacturing technology of a grain-oriented electrical steel sheet by secondary recrystallization in the {110} <001> orientation. Research has developed to secure superior magnetic properties by forming secondary recrystallizations with high degree of integration to {110} <001> orientation using a strong grain growth inhibitor.

On the other hand, when heating a slab for hot rolling, a method of manufacturing a so-called low-temperature-oriented electrical steel sheet in which the heating temperature is relatively lowered has been developed, and in this case, the slab is heated at a low temperature. The method of using an Al-based precipitate as a main grain growth inhibitor is proposed. Specifically, when an inhibitor is formed by such a low temperature heating method for slabs, the effect of Al-based nitrides to suppress crystal grain growth is strong, and as a manufacturing method to form secondary recrystallization more advantageously Proposed.
It is not easy to increase the content of Al to form an Al-based nitride above a certain level, and the content is limited. And, precisely control the content of Si and Mn, which are the main forming elements of Al-based nitride, and the content of C which indirectly influences each other in forming the composite nitride of Si and Mn. There is a need to.

Japanese Patent Re-Table 2008-133337

  This invention is made in view of said condition, Comprising: The place made into the objective is to provide the slab for directional electromagnetic steel plates, a directional electromagnetic steel plate, and its manufacturing method. Specifically, for a directional electrical steel sheet having excellent magnetism as a result by precisely adjusting the contents of Mn and C according to the content of Si in the slab for producing the magnetic steel sheet Provided are a slab, a grain-oriented electrical steel sheet, and a method of manufacturing the same.

The manufacturing method of the directionality electromagnetic steel sheet of the present invention for achieving the above object is, by mass%, Si: 3.0 to 5.0%, C: 0.01 to 0.15%, Mn: 0.1 Heating the slab containing 1.5% and the balance of Fe and other unavoidable impurities and satisfying the following formulas 1 and 2, and hot rolling the slab to produce a hot-rolled sheet , Cold-rolling a hot-rolled sheet to produce a cold-rolled sheet, primary re-crystallization annealing of the cold-rolled sheet, and secondary re-crystallization annealing of the cold-rolled sheet which has undergone primary recrystallization annealing And a stage.
Formula 1: 0.5 ≦ [Si] / (100 × [C] × [Mn]) ≦ 3
Formula 2: (0.04 × [Si] −0.075) − (0.045 × [Mn]) ≦ [C] ≦ (0.055 × [Si] −0.1) − (0.055 × [Mn])
In Formula 1 and Formula 2, [Si], [C], and [Mn] show content (mass%) of Si, C, and Mn, respectively.

The slab is made of Al: 0.01 to 0.04% by mass, and one or more of Sb and Sn alone or in a total amount of 0.03 to 0.1% by mass, N: 0.01% by mass or less However, 0 mass% can be excluded and S: 0.01% or less (however, except 0 mass%) can further be included.
In the stage of heating the slab, the heating temperature of the slab may be 1000 ° C to 1250 ° C.
After heating the slab, the austenite volume fraction in the slab is preferably 20 to 40%.
After the secondary recrystallization annealing step, it is preferable that the volume fraction of the texture having a crystal orientation in which the angle formed by the {100} plane with the rolling plane (ND plane) is 15 ° or less is 3% or less.

The grain-oriented electrical steel sheet slab of the present invention contains, by mass%, Si: 3.0 to 5.0%, C: 0.01 to 0.15%, Mn: 0.1 to 1.5%, the balance Is composed of Fe and other unavoidable impurities, and is characterized by satisfying Formula 1 and Formula 2 below.
Formula 1: 0.5 ≦ [Si] / (100 × [C] × [Mn]) ≦ 3
Formula 2: (0.04 × [Si] −0.075) − (0.045 × [Mn]) ≦ [C] ≦ (0.055 × [Si] −0.1) − (0.055 × [Mn])
In Formula 1 and Formula 2, [Si], [C], and [Mn] show content (mass%) of Si, C, and Mn, respectively.

The slab is made of Al: 0.01 to 0.04% by mass, and one or more of Sb and Sn alone or in a total amount of 0.03 to 0.1% by mass, N: 0.01% by mass or less However, 0 mass% can be excluded and S: 0.01% or less (however, except 0 mass%) can further be included.
The austenite volume fraction in the slab is preferably 20 to 40%.

The grain-oriented electrical steel sheet of the present invention contains, by mass%, Si: 3.0 to 5.0%, C: 0.005% or less (except 0%), and Mn: 0.1 to 1.5%. The remaining part is made of Fe and other unavoidable impurities, and the volume fraction of the texture having a crystal orientation in which the {100} plane makes an angle of 15 ° or less with the rolling plane (ND plane) is 3% or less. I assume.
The grain-oriented electrical steel sheet contains 0.01 to 0.04% by mass of Al, and 0.03 to 0.1% by mass or 0.01% by mass of one or more of Sb and Sn alone or in combination. It is preferable to further contain% or less (however, except 0 mass%) and S: 0.01% or less (however, except 0 mass%).

  According to the present invention, in the grain-oriented electrical steel sheet manufactured according to the present invention, by adjusting the contents of Mn and C according to the content of Si, the specific resistance of the steel sheet is high and a large number of Goss textures are formed. There is an effect to be a directional electromagnetic steel sheet excellent in magnetic properties.

The manufacturing method of the grain oriented electrical steel sheet of the present invention contains, by mass%, Si: 3.0 to 5.0%, C: 0.01 to 0.15%, Mn: 0.1 to 1.5%. The remaining portion consists of Fe and other unavoidable impurities, and the steps of heating the slab satisfying the following formulas 1 and 2; hot rolling the slab to produce a hot rolled sheet; and cold rolling the hot rolled sheet The steps of rolling to produce a cold rolled sheet, primary recrystallization annealing of the cold rolled sheet, and secondary recrystallization annealing of the cold rolled sheet having undergone primary recrystallization annealing are included.
Formula 1: 0.5 ≦ [Si] / (100 × [C] × [Mn]) ≦ 3
Formula 2: (0.04 × [Si] −0.075) − (0.045 × [Mn]) ≦ [C] ≦ (0.055 × [Si] −0.1) − (0.055 × [Mn])
In Formula 1 and Formula 2, [Si], [C], and [Mn] show content (mass%) of Si, C, and Mn, respectively.

Each step will be described in detail below.
First, heat the slab.
The slab contains Si: 3.0 to 5.0%, C: 0.01 to 0.15%, Mn: 0.1 to 1.5%, the balance being composed of Fe and other unavoidable impurities.
Hereinafter, each component of the slab will be described.

Si: 3.0 to 5.0% by mass
Silicon (Si) is a basic composition of a magnetic steel sheet, and plays a role in increasing core resistivity and improving core loss. If the content of Si is too low, the resistivity decreases, and the eddy current loss increases, resulting in poor core loss characteristics. On the other hand, when too much Si is added, the ductility and toughness of the mechanical properties decrease and not only plate breakage frequently occurs during the rolling process but also continuous annealing for commercial production At the same time, there is a possibility that the weldability between the plates is reduced to deteriorate the productivity. As a result, if the content of Si is not controlled to the above-mentioned range, not only the magnetic properties are impaired, but also the productivity may be deteriorated. Therefore, it is preferable to contain Si in the above-mentioned range, and more preferably, it is 3.5 to 5.0 mass% of Si.

C: 0.01 to 0.15 mass%
Carbon (C) is an austenite-stabilizing element, is added in the slab, and can refine coarse columnar structures generated in the continuous casting process and suppress segregation of sulfur (S) to the slab center . In addition, work hardening of the steel sheet can be promoted during cold rolling, and secondary recrystallization nucleation in the {110} <001> orientation can be promoted in the steel sheet. However, if too much is added, edge-cracks may occur during hot rolling. Therefore, it is preferable to contain C in the above-mentioned range.
However, in the production process of the magnetic steel sheet, decarburization annealing is to be performed during primary recrystallization annealing, and the content of C in the final oriented magnetic steel sheet that has undergone decarburization annealing is 0.005 mass% or less Is preferable and it is more preferable that it is 0.003 mass% or less.

Mn: 0.1 to 1.5 mass%
Manganese (Mn), like Si, has the effect of reducing iron loss by increasing resistivity and reducing eddy current loss. Also, the crystal grain growth is suppressed by reacting with S present in the steel to form a Mn-based compound, or by reacting with Al and nitrogen to form a nitride of the (Al, Si, Mn) N form. Play a role. If the content of Mn is too small, the above effect can not be expected, and if the content of Mn is too large, the austenitic phase transformation rate increases during secondary recrystallization annealing and the Goss texture is largely damaged. There is a possibility that the magnetic characteristics may be rapidly reduced.

Al: 0.01 to 0.04 mass%
Aluminum (Al) combines with nitrogen ions introduced by ammonia gas, which is an atmosphere gas for nitriding in the primary recrystallization annealing process, to form nitrides in the form of AlN as well as forming a solid solution state in the steel In combination with Si, Mn, and the above-described nitrogen ions to form a nitride of the (Al, Si, Mn) N form, thereby playing the role of a grain growth inhibitor. When the content is too small, the above-mentioned role can not be expected, and when the content is too large, a very coarse nitride is formed, which may cause the crystal grain growth suppressing power to be sharply reduced. . Therefore, when Al is additionally contained, the content of Al is preferably adjusted to the above range.

Sb and Sn: 0.03 to 0.1% by mass
The addition of tin (Sn) can improve the core loss by increasing the number of secondary grain nuclei of {110} <001> orientation. Sn also plays an important role in suppressing grain growth through segregation at grain boundaries. This compensates for the fact that the AlN and MnS precipitates are coarsened and the effect of suppressing grain growth is weakened when the temperature rising rate becomes low in the secondary annealing stage. However, when the content of Sn is too large, there is a possibility that the problem of increased brittleness may occur.
Antimony (Sb) is segregated at grain boundaries and has an effect of suppressing excessive growth of primary recrystallized grains. By suppressing grain growth in the primary recrystallization annealing stage by adding Sb, the nonuniformity of the size of the primary recrystallized grain along the thickness direction of the steel plate is removed, and at the same time secondary recrystallization is performed. By forming it stably, it is possible to make a grain-oriented electrical steel sheet with even more excellent magnetism. When the content of Sb is too small, the suppressing effect is insufficient, and when the content of Sb is too large, decarburization at the time of primary recrystallization annealing may be hindered to deteriorate the magnetic properties.
Such Sn and Sb may be included alone or together. When one or more of Sb and Sn are additionally contained, any one of Sb and Sn can be contained alone or in a total amount of 0.03 to 0.1% by mass. In other words, only Sb alone is contained 0.03 to 0.1% by mass, only Sn alone is contained 0.03 to 0.1% by mass alone, or Sb and Sn are simultaneously contained, and the total is 0.03 It can be ̃0.1 mass%.

N: 0.01 mass% or less Nitrogen (N) is an element which reacts with Al and Mn to form a compound such as AlN and (Al, Mn, Si) N, and N is additionally contained. And 0.01% by mass or less in the slab. If too much N is added, it will not only induce surface defects such as blisters due to nitrogen diffusion in the process after hot rolling, but also excessive nitride will be formed in the slab state, so It is not easy and causes a rise in manufacturing cost. Accordingly, the content of N is preferably limited to 0.01% by mass or less. After that, reinforcement of nitride for secondary recrystallization formation of Goss texture is carried out by nitriding treatment which introduces ammonia gas as atmosphere gas during decarburizing annealing process so that nitrogen diffuses into steel. To reinforce. After this, nitrogen is partially removed by secondary recrystallization annealing, and the content of N becomes 0.01 mass% or less even in the steel plate finally manufactured. Specifically, the slab and the steel plate may be controlled to contain N at 0.005% by mass or less.

S: 0.01 mass% or less Sulfur (S) segregates in the center of the slab during casting to cause brittleness, and further reacts with Mn in the steel to form a Mn-based sulfide to form a microstructure. Make it uneven and worsen the rollability. Therefore, it is not preferable that S be added and precipitated more than the content which is contained unavoidable. Even when S is additionally contained, the content of S is preferably controlled to 0.01 mass% or less.

In one embodiment of the present invention, the slab may satisfy Formula 1 and Formula 2 below.
Formula 1: 0.5 ≦ [Si] / (100 × [C] × [Mn]) ≦ 3
Formula 2: (0.04 × [Si] −0.075) − (0.045 × [Mn]) ≦ [C] ≦ (0.055 × [Si] −0.1) − (0.055 × [Mn])
(However, in Formula 1 and Formula 2, [Si], [C] and [Mn] respectively indicate the content (mass%) of Si, C and Mn.)
Hereafter, the content regarding the restriction | limiting of the component of Formula 1 and Formula 2 is demonstrated.

  During the manufacturing process of the grain-oriented electrical steel sheet, the microstructure of the steel sheet has a ferrite structure and an austenite structure simultaneously at the temperature at which the slab is heated. At this time, when the volume fraction of the austenitic structure is in the range of 20% to 40% of the whole area, the magnetic properties of the final directionality electrical steel sheet are most excellent. When the austenite volume fraction is less than 20%, the stretched structure having a {100} crystal plane does not disappear at the center of the slab, and the magnetic flux density and the core loss characteristics are deteriorated until the final product stage. When the austenite volume fraction exceeds 40%, many phase transformations occur to reduce the amount of Goss texture generated during the hot rolling process, which may result in a steel material inferior in magnetic properties. Therefore, it is important to maintain the volume fraction of austenite structure in the range of 20 to 40% at the time of slab heating.

The fraction of the austenitic structure of the slab varies with the amount of alloying elements added. In general, Si is an element that enhances the ferrite fraction, and C and Mn are elements that enhance the austenite fraction. Therefore, if the content of Si is increased to increase the specific resistance of the steel plate, the ferrite fraction of the slab increases, so C or Mn must be added to control to maintain an appropriate austenite fraction.
For this reason, adjustment of content of C and Mn according to content of Si is required, The range can be represented like said Formula 1. FIG. When the left side of Formula 1 is less than 0.5, the austenite phase fraction exceeds the appropriate level, and when the right side of Formula 1 exceeds 3, the austenite fraction becomes less than the appropriate level.

On the other hand, the above-mentioned formula 2 is a formula showing the range of content of C according to content of Si and Mn. An object of the present invention is to make a grain-oriented electrical steel sheet excellent in magnetism by increasing the specific resistance of the steel sheet. In the case of C, there is no relationship with the increase in specific resistance of the grain-oriented electrical steel sheet, and as described above, C in the initial slab is reduced to 0.003 mass% or less by the decarburization process in the primary recrystallization annealing step I have to let it go.
On the other hand, Mn is an element which raises the specific resistance of the steel plate as the amount of addition increases. Therefore, in order to increase the specific resistance of the steel sheet while forming an appropriate austenite structure at the time of heating the slab, it is more effective to increase the content of Mn rather than adding C. At this time, the content of C should be lowered as the content of Mn is increased. This is because both C and Mn are elements that increase the austenite fraction, as described above. Further, as the content of Si increases, the range of the content of Mn and C for maintaining an appropriate austenite fraction changes, so the range of C is the content of Si and Mn as shown in Formula 2. It is preferable to express in the complex relation of

The temperature at the stage of heating the slab will be described. By heating the slab at a temperature of 1250 ° C. or less, it is possible to prevent the columnar crystal structure of the slab from growing coarsely and to prevent the plate from being cracked in the hot rolling process. When the temperature is less than 1000 ° C., the rolling load is increased because the hot rolling temperature is low and the deformation resistance of the steel sheet is increased. Therefore, it is preferable that the heating temperature of a slab is 1000 degreeC-1250 degreeC.
Next, the slab is hot-rolled to produce a hot-rolled sheet. The hot rolling temperature is not limited, and in one embodiment, the hot rolling is completed at 950 ° C. or less. After that, it can be water cooled and wound up at 600 ° C. or less. It can be manufactured to a hot-rolled sheet with a thickness of 1.5 to 5.0 mm by hot rolling.
The hot-rolled hot-rolled sheet can be subjected to hot-rolled sheet annealing or cold-rolled without being subjected to hot-rolled sheet annealing, as necessary. When performing hot-rolled sheet annealing, in order to make the hot-rolled structure uniform, it is preferable to heat at a temperature of 900 ° C. or higher, and to cool after being equalized.

  Subsequently, the hot-rolled sheet is cold-rolled to produce a cold-rolled sheet. Cold rolling is performed by multiple cold rolling methods including single cold rolling, multiple cold rolling, or intermediate annealing using a reverse rolling mill or a tandem (Tandem) rolling mill. A cold rolled sheet having a thickness of 1 mm to 0.5 mm can be manufactured. Furthermore, it is preferable to perform warm rolling which maintains the temperature of a steel plate at 100 degreeC or more during cold rolling. The final rolling reduction by cold rolling is 50 to 95%.

Next, the cold rolled cold rolled sheet is subjected to primary recrystallization annealing. At the primary recrystallization annealing stage, primary recrystallization which becomes a nucleus of Goss grains occurs. In the primary recrystallization annealing process, decarburization and nitriding of the steel plate are performed. For decarburization and nitriding, primary recrystallization annealing is preferably performed in a mixed gas atmosphere of water vapor, hydrogen, and ammonia.
A method of decarburizing and nitriding in forming nitrides such as (Al, Si, Mn) N and AlN of the main precipitates by introducing nitrogen ions into a steel plate using ammonia gas for nitriding Alternatively, there is a method of simultaneously performing nitriding treatment so as to simultaneously carry out nitriding treatment simultaneously with decarburizing, or a method of performing decarburization after first performing nitriding treatment, but any method exhibits the effect of the present invention There is no problem with the above.

Finally, the secondary recrystallization annealing is performed on the cold-rolled sheet on which the primary recrystallization annealing has been completed. At this time, it is preferable that secondary recrystallization annealing be performed after the annealing separator is applied to the cold-rolled sheet on which the primary recrystallization annealing has been completed. The annealing separator at this time is not particularly limited, and an annealing separator containing MgO as a main component can be used.
One embodiment of the present invention provides a directional electrical steel sheet slab. The directional electromagnetic steel plate slab has been described in detail in the heating step of the slab in the process of manufacturing the directional electromagnetic steel plate described above, and thus the overlapping description will be omitted.

It is preferable that the volume fraction of the texture having a crystal orientation in which the angle between the {100} plane and the rolling plane (ND plane) is 15 ° or less is 3% or less .
In one embodiment of the present invention, by precisely controlling the content of Si, C and Mn in the slab, it is possible to properly control the austenite fraction in the slab after heating the slab, thereby Stretched texture with 100} crystal faces can be minimized. It is possible to manufacture a grain-oriented electrical steel sheet which is extremely excellent in magnetism.
Specifically, iron loss is 0.85 W / kg or less under the conditions of 1.7 T (T is SI unit of magnetic flux density: Tesla) and 50 Hz of the grain-oriented electrical steel sheet manufactured according to one embodiment of the present invention Good to have. More specifically, the core loss is preferably 0.73 to 0.83 W / kg.

The magnetic flux density induced under a magnetic field of 800 A / m of the grain-oriented electrical steel sheet manufactured according to an embodiment of the present invention may be 1.90 T or more. More specifically, it can be 1.90 to 1.95T.
The alloy composition of the finally manufactured grain-oriented electrical steel sheet has been described in detail in the above-mentioned alloy composition of the slab, and therefore, redundant description will be omitted.
Hereinafter, preferred examples and comparative examples of the present invention will be described. However, the following embodiments are only preferred embodiments of the present invention, and the present invention is not limited to the following embodiments.

EXAMPLES The composition of the alloying elements and the balance shown in Table 1 below prepared a slab consisting of Fe and other unavoidable impurities. The slab was heated at a temperature of 1150 ° C. for 90 minutes and the austenite fraction was measured. Then, it hot-rolled and manufactured the 2.3-mm-thick hot-rolled sheet. The hot-rolled sheet was heated at a temperature of 1050 ° C. or higher, maintained at 910 ° C. for 70 seconds, water-cooled and then pickled. Next, a reverse rolling mill was used to cold-roll to a thickness of 0.23 mm after a total of six passes. A cold-rolled steel plate is heated in a furnace and then maintained at a mixed gas atmosphere of hydrogen: 50% by volume and nitrogen: 50% by volume, a dew point temperature of 60 ° C., and an annealing temperature of 850 ° C. for 120 seconds. Next recrystallization annealing was performed. Thereafter, after MgO was applied, it was wound into a coil and subjected to secondary recrystallization annealing. The secondary recrystallization annealing is performed by raising the temperature to 1200 ° C. in a mixed gas atmosphere of nitrogen: 25% by volume and hydrogen: 75% by volume, and after reaching 1200 ° C., maintaining it in a hydrogen: 100% by volume gas atmosphere for 20 hours It was cold.

After finally cleaning the surface of the steel plate obtained, the insulating coating solution was applied and annealed at 830 ° C. for 30 seconds. Thereafter, the core loss was measured under the conditions of 1.7 T and 50 Hz using the single sheet measurement method, and the magnitude (Tesla) of the magnetic flux density induced under a magnetic field of 800 A / m was measured. Each iron loss value shows the average according to conditions.
Also, the fraction of texture having the {100} crystal face of the finally obtained steel plate was analyzed.

表１から確認できるとおり、Ｓｉ、ＣおよびＭｎの含有量を本発明の範囲内で制御した発明材１〜５の場合に、比較材１〜４に比べて優れた鉄損および磁束密度値を得ることができた。これは、スラブの加熱時、スラブ内のオーステナイト分率が精密に制御されて｛１００｝結晶面が残存する現象を抑制し、最終方向性電磁鋼板内でゴス集合組織を多量形成するからである。

As can be confirmed from Table 1, in the case of the inventive materials 1 to 5 in which the contents of Si, C and Mn are controlled within the range of the present invention, the core loss and the magnetic flux density value superior to the comparative materials 1 to 4 I was able to get it. This is because when the slab is heated, the austenite fraction in the slab is precisely controlled to suppress the phenomenon in which the {100} crystal face remains, and a large amount of Goss texture is formed in the final oriented electrical steel sheet. .

  The present invention is not limited to the above-described embodiments, but is manufactured in various forms different from each other, and those having ordinary knowledge in the technical field to which the present invention belongs can understand the technical idea and essentials of the present invention. It will be understood that it can be implemented in other specific forms without changing the features. Therefore, it should be understood that the embodiments described above are illustrative in all aspects and not limiting.

Claims (10)

Si: 3.0 to 5.0%, C: 0.01 to 0.15%, Mn: 0.1 to 1.5% by mass, the balance being composed of Fe and other unavoidable impurities, Heating the slab satisfying the following formulas 1 and 2;
Hot rolling the slab to produce a hot rolled sheet;
Cold rolling the hot rolled sheet to produce a cold rolled sheet;
Performing primary recrystallization annealing on the cold rolled sheet;
And D. secondary recrystallization annealing of the cold-rolled sheet on which the primary recrystallization annealing has been completed.
Formula 1: 0.5 ≦ [Si] / (100 × [C] × [Mn]) ≦ 3
Formula 2: (0.04 × [Si] −0.075) − (0.045 × [Mn]) ≦ [C] ≦ (0.055 × [Si] −0.1) − (0.055 × [Mn])
(However, in Formula 1 and Formula 2, [Si], [C] and [Mn] respectively indicate the content (mass%) of Si, C and Mn.)   The slab may contain Al: 0.01 to 0.04% by mass, and one or more of Sb and Sn alone or in a total amount of 0.03 to 0.1% by mass, and N: 0.01% by mass or less The method for producing a grain-oriented electrical steel sheet according to claim 1, further comprising (excluding 0% by mass) and S: 0.01% or less (excluding 0% by mass).   The method according to claim 1 or 2, wherein, in the heating of the slab, a heating temperature of the slab is 1000 ° C to 1250 ° C.   The method for producing a grain-oriented electrical steel sheet according to any one of claims 1 to 3, wherein the austenite volume fraction in the slab is 20 to 40% after the step of heating the slab.   After the step of secondary recrystallization annealing, the volume fraction of the texture having a crystal orientation in which the {100} plane makes an angle of 15 ° or less with the rolling plane (ND plane) is 3% or less. The manufacturing method of the directionality electromagnetic steel sheet according to any one of claims 1 to 4. Si: 3.0 to 5.0%, C: 0.01 to 0.15%, Mn: 0.1 to 1.5% by mass, the balance being composed of Fe and other unavoidable impurities, A slab for a directional electrical steel sheet characterized by satisfying the following Formula 1 and Formula 2.
Formula 1: 0.5 ≦ [Si] / (100 × [C] × [Mn]) ≦ 3
Formula 2: (0.04 × [Si] −0.075) − (0.045 × [Mn]) ≦ [C] ≦ (0.055 × [Si] −0.1) − (0.055 × [Mn])
(However, in Formula 1 and Formula 2, [Si], [C] and [Mn] respectively indicate the content (mass%) of Si, C and Mn.)   The slab may contain Al: 0.01 to 0.04% by mass, and one or more of Sb and Sn alone or in a total amount of 0.03 to 0.1% by mass, and N: 0.01% by mass or less The slab according to claim 6, further comprising (excluding 0% by mass) and S: 0.01% or less (excluding 0% by mass).   The austenite volume fraction in the said slab is 20 to 40%, The slab for the directionality electromagnetic steel plate of Claim 6 or 7 characterized by the above-mentioned.   Si: 3.0 to 5.0%, C: 0.005% or less (except 0%), Mn: 0.1 to 1.5% by mass, the balance being Fe and other unavoidable impurities A grain-oriented electrical steel sheet characterized in that the volume fraction of the texture having a crystal orientation in which the {100} plane makes an angle of 15 ° or less with the rolling plane (ND plane) is 3% or less.   The electromagnetic steel sheet comprises Al: 0.01 to 0.04% by mass, and one or more of Sb and Sn individually or in combination of 0.03 to 0.1% by mass, N: 0.01% by mass The oriented electrical steel sheet according to claim 9, further comprising the following (excluding 0% by mass) and S: 0.01% or less (excluding 0% by mass).