KR20190078230A - Grain oriented electrical steel sheet, and method for manufacturing grain oriented electrical steel sheet - Google Patents

Abstract

A grain oriented electrical steel sheet according to an embodiment of the present invention comprises a base steel sheet and a linear ceramic layer positioned on the base steel sheet, wherein the linear ceramic layer forms an angle of 82° to 88° or 92° to 98° with respect to the rolling direction of the steel sheet.

Description

TECHNICAL FIELD [0001] The present invention relates to a directional electric steel sheet and a method for manufacturing a directional electric steel sheet,

A directional electric steel sheet and a method of manufacturing a directional electric steel sheet. More specifically, the present invention relates to a directional electrical steel sheet and a method of manufacturing a grain-oriented electrical steel sheet, in which a line-shaped ceramic layer is formed on a base steel sheet and its angle with the rolling direction is controlled.

A grain-oriented electrical steel sheet is an electrical steel sheet containing a Si component and having an aggregate structure in which the grain orientations are aligned in the {110} < 001 > direction, and has extremely excellent magnetic properties in the rolling direction.

In particular, iron core materials for transformers are required to have low iron losses in order to reduce energy loss. Since it is effective to apply a tensile force to a steel sheet in order to manufacture an electrical steel sheet having a small iron loss, methods of imparting tensile force to the steel sheet and reducing iron loss by forming a film made of a material having a lower thermal expansion coefficient at a higher temperature than the steel sheet have.

In order to minimize the power loss of the directional electrical steel sheet, it is common to form an insulating film on the surface thereof. In this case, the insulating film is basically made of a material having a high electrical insulating property, excellent adhesion with a material, . In addition, due to recent intensification of international standards for transformer noise and intensifying competition in the related industry, researches on magnetostriction (magnetostrictive) phenomenon are required to reduce the noise of the insulating coating of a directional electrical steel sheet.

Specifically, when a magnetic field is applied to an electric steel sheet used as an iron core of a transformer, the shrinkage and expansion are repeated to cause a trembling phenomenon, which causes vibration and noise in the transformer.

In the case of a generally known directional electric steel sheet, an insulating layer is formed on a steel sheet and a Forsterite base coat, and a tensile stress is applied to the steel sheet using the difference in thermal expansion coefficient of the insulating layer, , But there is a limit to satisfy the noise level in the advanced directional electric steel sheet which is recently required.

On the other hand, a wet coating method is known as a method of reducing a 90 占 magnetic domain of a directional electric steel sheet. Here, the 90 占 magnetic domain refers to a region having magnetization oriented at right angles to the magnetic field application direction. The smaller the amount of the 90 占 magnetic domain, the smaller the magnetostriction. However, in the general wet coating method, there is a problem that noise reduction effect by tensile stress application is insufficient and coating thickness is thicker than that of a thick film, which results in a problem that the transformer drop rate and efficiency become poor.

To provide a directional electrical steel sheet and a method of manufacturing a directional electrical steel sheet. More specifically, it is intended to provide a method of manufacturing a grain-oriented electrical steel sheet and a grain-oriented electrical steel sheet in which a line-shaped ceramic layer is formed on a base steel sheet and its angle with the rolling direction is controlled.

A directional electrical steel sheet according to an embodiment of the present invention includes: a base steel sheet; And a line-shaped ceramic layer positioned on the base steel sheet, and the line-shaped ceramic layer has an angle of 82 to 88 ° or 92 to 98 ° with the rolling direction of the steel sheet.

A plurality of linear ceramic layers are present, and a plurality of ceramic layers can form a pattern along the rolling direction of the steel sheet.

The width of the ceramic layer may be 5.0 to 30 mm.

The distance between the ceramic layers may be 2.0 to 10.0 mm.

The porosity of the ceramic layer is 1% or less.

The ceramic layer may have a surface roughness of 1 mu m or less.

The thickness of the ceramic layer may be 0.1 to 3.5 mu m.

The ceramic layer may be made of a ceramic powder.

The ceramic powder includes at least one selected from Li, B, Ca, Sr, Mg, Al, Si, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Oxide, nitride, carbide, or oxynitride.

The ceramic powder may be at least one selected from the group consisting of Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , MgO · Al ₂ O ₃ , 2MgO · SiO ₂ , MgO · SiO ₂ , 2MgO · TiO ₂ , MgO · TiO ₂ , MgO · 2TiO ₂ , Al _{2 O 3 · SiO 2, 3Al} 2 O 3 · 2SiO 2, Al 2 O 3 · TiO 2, ZnO · SiO 2, ZrO 2 · SiO 2, ZrO 2 · TiO 2, 9Al 2 O 3 · 2B 2 O 3, _{2Al 2 O 3 · B 2 O} 3, 2MgO · 2Al 2 O 3 · 5SiO 2, Li 2 O · Al 2 O 3 · SiO 2, Li 2 O · Al 2 O 3 · 4SiO 2, BaO · Al 2 O 3 _{· SiO 2, AlN, SiC,} TiC, TiN, BN, ZrN, CrN, BaTiO 3, SrTiO 3, FeTiO 3, MgTiO 3, CaO, FeAl 2 O 4, CaTiO 3, MgAl 2 O 4, FeTiO 4, SrZrO 3 , Y ₂ O ₃ , CoAl ₂ O ₄ , and ZrSiO ₄ .

And a metal oxide layer formed between the base steel sheet and the ceramic layer.

The base steel sheet comprises 2.6 to 5.5 wt% of silicon (Si), 0.020 to 0.040 wt% of aluminum (Al), 0.01 to 0.20 wt% of manganese (Mn), antimony (Sb), tin (Sn) By weight and 0.01 to 0.15% by weight, the remainder being Fe and other unavoidable impurities.

A method of manufacturing a directional electrical steel sheet according to an embodiment of the present invention includes the steps of: preparing a base steel sheet; And forming a linear ceramic layer on the base steel sheet by spraying the ceramic powder at an angle of 82 to 88 DEG or 92 to 98 DEG with respect to the rolling direction.

The step of producing the base steel sheet comprises the steps of: producing a slab; Heating the slab; Hot rolling the slab to produce a hot-rolled steel sheet; A step of cold-rolling the hot-rolled steel sheet to produce a cold-rolled steel sheet; A first recrystallization annealing step for the cold-rolled steel sheet, and a secondary recrystallization annealing step for the first recrystallization annealed steel sheet.

After the primary recrystallization annealing step, the annealing separator may further be applied.

In the step of forming the on-line ceramic layer, a plurality of linear ceramic layers may be formed, and a plurality of ceramic layers may form a pattern along the rolling direction of the steel sheet.

The step of forming the on-line ceramic layer includes the steps of supplying a ceramic powder to a heat source in which a gas containing at least one of Ar, H ₂ , N ₂ , or He is converted into plasma at an output of 20 to 300 kW, As shown in FIG.

The average particle size of the ceramic powder may be 10 to 1000 nm.

In the grain-oriented electrical steel sheet according to an embodiment of the present invention, the line-shaped ceramic layer forms an appropriate angle with the rolling direction, thereby achieving the effect of imparting tension and the effect of refining the magnetic domain.

Further, the grain-oriented electrical steel sheet according to an embodiment of the present invention is excellent in insulation characteristics.

Further, a transformer in which the noise is reduced can be manufactured by using the directional electrical steel sheet according to an embodiment of the present invention.

1 is a schematic view schematically showing a rolled surface (ND side) of a grain-oriented electrical steel sheet according to an embodiment of the present invention.
2 is a schematic view schematically showing a cross section of a directional electric steel sheet according to another embodiment of the present invention.

The terms first, second and third, etc. are used to describe various portions, components, regions, layers and / or sections, but are not limited thereto. These terms are only used to distinguish any moiety, element, region, layer or section from another moiety, moiety, region, layer or section. Thus, a first portion, component, region, layer or section described below may be referred to as a second portion, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified and that the presence or absence of other features, regions, integers, steps, operations, elements, and / It does not exclude addition.

When referring to a portion as being "on" or "on" another portion, it may be directly on or over another portion, or may involve another portion therebetween. In contrast, when referring to a part being "directly above" another part, no other part is interposed therebetween.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Unless otherwise stated,% means% by weight, and 1 ppm is 0.0001% by weight.

In an embodiment of the present invention, the term further includes an additional element, which means that an additional amount of the additional element is substituted for the remaining iron (Fe).

"A to B" means not less than A and not more than B unless otherwise defined.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

1 schematically shows a cross section of a directional electrical steel sheet according to an embodiment of the present invention. As shown in FIG. 1, the directional electrical steel sheet 100 according to one embodiment of the present invention includes a base steel sheet 10; And a linear ceramic layer (30) located on the base steel sheet (10). The directional electrical steel sheet of Fig. 1 is only for illustrating the present invention, and the present invention is not limited thereto.

The line-shaped ceramic layer 30 may have an angle (?) With the rolling direction (RD direction) of the steel sheet is 82 to 88 degrees or 92 to 98 degrees. By controlling the angle of the ceramic layer 30 in this way, it is possible to maximize the effect of imparting tension and the effect of miniaturization of the magnetic domain.

The ceramic layer 30 on the line means a shape similar to a parallelogram. The angle? Formed by the long sides of two pairs of long sides and the rolling direction (RD direction) is 82 to 88 占 or 92 to 98 占Lt; / RTI &gt; The short side may be formed parallel to the rolling direction (RD direction).

The angle formed by the line-shaped ceramic layer 30 and the rolling direction (RD direction) of the steel sheet is close to a right angle (90 DEG), and the effect of miniaturization of the magnetic domain is remarkably deteriorated. Further, even when the angle? Is smaller than 88 占 or larger than 96 占, the effect of miniaturization of the magnetic domain is remarkably deteriorated. More specifically, the line-shaped ceramic layer 30 may have an angle (?) With the rolling direction (RD direction) of the steel sheet is 84 to 86 degrees or 94 to 96 degrees.

The base steel sheet 10 is composed of 2.6 to 5.5% by weight of silicon (Si), 0.020 to 0.040% by weight of aluminum (Al), 0.01 to 0.20% by weight of manganese (Mn), antimony (Sb) 0.01 to 0.15% by weight of the combination thereof, and the balance of Fe and other unavoidable impurities.

Hereinafter, the reason for limiting the constituents of the base steel sheet 10 will be described.

Si: 2.6 to 5.5 wt%

Silicon (Si) increases the resistivity of the steel to reduce iron loss. When the content of Si is too small, the resistivity of the steel becomes small and the iron loss characteristic deteriorates. In the high temperature annealing, Problems can arise. If the content of Si is too large, the brittleness is increased and cold rolling may become difficult. Therefore, the content of Si can be controlled within the above-mentioned range. More specifically, Si may be contained in an amount of 2.6 to 4.3% by weight.

Al: 0.020 to 0.040 wt%

Aluminum (Al) is finally a component that acts as an inhibitor by being made of nitride of (Al, Si, N), (Al, Si, Mn) N type. When the content of Al is too small, it is difficult to expect a sufficient effect as an inhibitor. When the content of Al is too large, the nitride of the Al system precipitates and grows too much, so that the effect as an inhibitor may become insufficient. Therefore, the content of Al can be controlled within the above-mentioned range.

Mn: 0.01 to 0.20 wt%

Mn has the effect of increasing the resistivity and decreasing the iron loss by the same way as Si and reacting with the nitrogen introduced by the nitriding treatment together with Si to form precipitates of N (Al, Si, Mn), whereby the growth of the primary recrystallized grains And it is an important element for causing secondary recrystallization. However, when the content of Mn is too large, it accelerates the austenite phase transformation during hot rolling so that the size of the primary recrystallized grains is reduced to make the secondary recrystallization unstable. When the content of Mn is too small, the effect of increasing the austenite fraction during hot-rolling reheating as the austenite forming element to increase the amount of precipitates and thus to make the primary recrystallization through MnS formation not too much It can occur insufficiently. Therefore, the content of Mn can be controlled within the above-mentioned range.

Sb, Sn or a combination thereof: 0.01 to 0.15 wt%

Since Sb or Sn is an element which interferes with the grain boundary movement as a grain boundary segregation element, generation of goss grain in the {110} < 001 > orientation is promoted as a grain growth inhibitor so that secondary recrystallization is well developed, to be. If the content of Sb or Sn added alone or in combination is too small, the effect may be deteriorated. If the content of Sb or Sn added alone or in combination is too large, grain boundary segregation occurs severely and the brittleness of the steel sheet becomes large, so that plate breakage may occur during rolling.

In order to improve the noise characteristics, the grain size of the high-temperature annealing grain is miniaturized in the steel sheet to reduce the 90 ° magnetic domain because the noise of the grain-oriented electrical steel sheet is caused by vibration caused by magnetostriction. However, in a conventional method for producing a grain-oriented electrical steel sheet, the crystal grain size is large and non-uniform, and the noise improving effect is insufficient.

The base steel sheet 10 according to an embodiment of the present invention has excellent effect of improving transformer noise by controlling Sb or Sn alone or in combination to have a grain size of 10 to 60 mm. If the grain size is too small, the magnetic flux density is insufficient, which is not enough to produce a product such as a transformer. If the crystal grain size is too large, the magnetostriction becomes severe and it becomes difficult to manufacture a low noise transformer. In this case, the grain size means a circle equivalent diameter measured using the intercept method.

As shown in FIG. 2, in one embodiment of the present invention, the ceramic layer 30 is located on the substrate steel sheet 10. 2, a metal oxide layer 20 may be further formed between the ceramic layer 30 and the base steel sheet 10. In this case, the ceramic layer 30 is formed on the metal oxide layer 20 do. The metal oxide layer 20 may include forsterite. The metal oxide layer 20 is not essential and the ceramic layer 30 may be directly formed on the base steel sheet 10 by removing or suppressing the metal oxide layer 20. [

2, the metal oxide layer 20 and the ceramic layer 30 are formed on one side of the base steel sheet 10, but the present invention is not limited thereto. The metal oxide layer 20 and the ceramic layer 30 may be formed on both sides of the base steel sheet 10, It is also possible that the ceramic layer 30 is formed.

The line-shaped ceramic layer 30 may have an angle (?) With the rolling direction (RD direction) of the steel sheet is 82 to 88 degrees or 92 to 98 degrees. By controlling the angle of the ceramic layer 30 in this way, it is possible to maximize the effect of imparting tension and the effect of miniaturization of the magnetic domain.

As shown in Figs. 1 and 2, a plurality of linear ceramic layers 30 are present, and a plurality of ceramic layers 30 can form a pattern along the rolling direction (RD direction) of the steel sheet. Forming a pattern means repeating that the plurality of ceramic layers 30 having a constant width w form a constant distance d.

The width w of the ceramic layer 30 may be 5.0 to 30 mm. If the width w is too small, the effect of improving the iron loss due to the application of the tensile force is insignificant, and a large number of coating nozzles must be formed. If the width (w) is too small, the magnetic domain refining effect may be weakened. Therefore, the width w of the ceramic layer 30 can be controlled within the range described above. Specifically, the width w of the ceramic layer 30 may be 8 to 20 mm. Specifically, the width w of the ceramic layer 30 means the distance between the long sides in the parallelogram forming the ceramic layer 30 on the line.

The distance d between the ceramic layers 30 may be 2.0 to 10.0 mm. If the spacing d is too small, there may arise a problem that the surface roughness is made rough by forming a double layer of the ceramic layer in a part of the area, and the spot rate is deteriorated when the transformer is manufactured. A technique of removing a part of a steel sheet by using the conventional laser irradiation has a problem that re-coating is required because insulation is weakened by inducing peeling of an insulating coating layer. In addition, there is a problem that there is a restriction in use because the iron loss improvement effect disappears when the heat treatment process is performed by the customer. Is fundamentally different from the negative type process of forming a ceramic coating on the entire plate surface of a steel sheet and removing the ceramic coating 30 in the sense that the interval d between the ceramic layers 30 is wide. In the case of the negative type process, the interval d between the ceramic layers 30 can not be made wide as in the embodiment of the present invention. When the interval d is too wide, it is difficult to appropriately obtain the desired magnetic domain refining effect. More specifically, the distance d between the ceramic layers 30 may be 3 to 7 mm. The distance between the ceramic layers 30 means the distance between the long sides in the parallelogram in the adjacent ceramic layers 30 on the line.

The ceramic layer 30 may be formed by spraying a ceramic powder in the embodiment of the present invention. The ceramic layer 30 thus formed may have a very low porosity and may be formed of the base steel sheet 10 or the metal oxide layer 20, And is very excellent in adhesion to the substrate. Specifically, the porosity of the ceramic layer 30 is 1% or less. Here, the porosity means the area fraction occupied by the pores with respect to the total area of the cross section of the ceramic layer 30.

The ceramic layer 30 formed by the method of forming the ceramic layer 30 by spraying the ceramic powder has a very small surface roughness Ra. By reducing the surface roughness (Ra) of the ceramic layer (30), it is possible to improve the dropping rate and to prevent the problem that the no load of the transformer is lowered. Specifically, the surface roughness of the ceramic layer 30 may be 1 占 퐉 or less.

The thickness C of the ceramic layer 30 may be 0.1 to 3.5 占 퐉. If the thickness C of the ceramic layer 30 is too small, the amount of the tensile force generated on the surface of the grain-oriented electrical steel sheet by the ceramic layer is small, and the iron loss reducing effect and insulating effect may be insufficient. On the other hand, if the thickness C of the ceramic layer 30 is too large, the adhesion of the ceramic layer 30 becomes low, and peeling may occur. More specifically, the thickness C of the ceramic layer 30 may be 1 to 3 占 퐉.

The ceramic layer 30 may be made of ceramic powder. The ceramic powder includes at least one selected from Li, B, Ca, Sr, Mg, Al, Si, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Oxide, nitride, carbide, or oxynitride. More specifically, the ceramic powder may be selected from the group consisting of Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , MgO · Al ₂ O ₃ , 2MgO · SiO ₂ , MgO · SiO ₂ , 2MgO · TiO ₂ , MgO · TiO ₂ , MgO · 2TiO _{2, Al 2 O 3 · SiO} 2, 3Al 2 O 3 · 2SiO 2, Al 2 O 3 · TiO 2, ZnO · SiO 2, ZrO 2 · SiO 2, ZrO 2 · TiO 2, 9Al 2 O 3 · 2B 2 _{O 3, 2Al 2 O 3 ·} B 2 O 3, 2MgO · 2Al 2 O 3 · 5SiO 2, Li 2 O · Al 2 O 3 · SiO 2, Li 2 O · Al 2 O 3 · 4SiO 2, BaO · Al _{2 O 3 · SiO 2, AlN} , SiC, TiC, TiN, BN, ZrN, CrN, BaTiO 3, SrTiO 3, FeTiO 3, MgTiO 3, CaO, FeAl 2 O 4, CaTiO 3, MgAl 2 O 4, FeTiO 4 _{, SrZrO 3, Y 2 O 3} , CoAl may include at least one selected from ₂ O _4, and ZrSiO _4.

The average particle diameter of the ceramic powder may be 10 to 1000 nm. If the particle diameter of the ceramic powder is too small, the formation of the ceramic layer 30 may become difficult. If the particle diameter of the ceramic powder is too large, the surface roughness may become coarse and surface defects may occur. Therefore, the particle diameter of the ceramic powder can be adjusted to the above-mentioned range.

The ceramic powder may be in the form of any one or more selected from the group including spherical, plate-like, and needle-shaped.

A method of manufacturing a directional electrical steel sheet according to an embodiment of the present invention includes the steps of: preparing a base steel sheet; And forming a linear ceramic layer on the base steel sheet by spraying the ceramic powder at an angle of 82 to 88 DEG or 92 to 98 DEG with respect to the rolling direction.

Each step will be described in detail below.

The step of producing the base steel sheet comprises the steps of: producing a slab; Heating the slab; Hot rolling the slab to produce a hot-rolled steel sheet; A step of cold-rolling the hot-rolled steel sheet to produce a cold-rolled steel sheet; A first recrystallization annealing step for the cold-rolled steel sheet, and a secondary recrystallization annealing step for the first recrystallization annealed steel sheet.

In the step of producing the slab, the slab may contain silicon (Si) in an amount of 2.6 to 5.5 wt%, aluminum (Al) in an amount of 0.020 to 0.040 wt%, manganese (Mn) in an amount of 0.01 to 0.20 wt%, antimony (Sb) , Or a combination thereof in an amount of 0.01 to 0.15% by weight, the balance being Fe and other unavoidable impurities. Since the components of the slab are the same as those of the above-described directional electrical steel sheet, the overlapping description will be omitted.

The step of heating the slab may first be heated to 1200 DEG C or less before hot rolling the slab. Further, the hot-rolled steel sheet produced after hot-rolling can be annealed. In addition, decarburization, decarburization and soaking can be performed during the primary recrystallization annealing. Since this process is performed according to a normal process, a detailed description is omitted.

As described above, in the series of steps of subjecting the slab having the composition according to an embodiment of the present invention to the hot rolling-cold rolling-primary recrystallization annealing-secondary recrystallization annealing, the average grain size of the grain after the secondary recrystallization annealing is 10 to 60 mm The process conditions can be controlled to meet the range.

After the primary recrystallization annealing, the annealing separator is applied to prevent sticking between the base steel sheets 10 during the secondary recrystallization annealing for forming the secondary recrystallization. At this time, the metal oxide layer 20 can be formed on the base steel sheet 10 by including MgO, Al ₂ O ₃ , or the like in the annealing separator component. Annealing separators can be used without limitation in commonly known compositions.

The secondary recrystallization annealing step includes a step of primary cracking at 600 to 750 ° C, a step of raising the temperature to 5 to 20 ° C / s, and a secondary cracking at 950 to 1300 ° C, for the steel sheet coated with the annealing separator . The primary cracking step and the step of heating can be performed in 10 to 60% by volume of hydrogen and the remaining nitrogen atmosphere, and the secondary cracking step can be performed in a hydrogen atmosphere of 90 vol% or more.

Next, the ceramic layer 30 is formed by spraying the ceramic powder onto the base steel sheet 10. When the metal oxide layer 20 is formed on the base steel sheet 10, the ceramic powder is sprayed onto the metal oxide layer 20. As a method of forming the ceramic layer 30, plasma spray coating, high velocity oxy fuel, aerosol deposition, and cold spray coating are applied .

More specifically, a plasma spray for spraying a ceramic powder onto a base steel sheet 10 by supplying a ceramic powder to a heat source formed by plasma-blowing a gas containing at least one of Ar, H ₂ , N ₂ or He at an output of 20 to 300 kW Coating method can be used.

The ceramic layer 30 can be formed by supplying the mixture of the ceramic powder and the solvent in suspension form to the plasmaized heat source. At this time, the solvent may be water or alcohol.

The ceramic powder includes at least one selected from Li, B, Ca, Sr, Mg, Al, Si, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Oxide, nitride, carbide, or oxynitride.

The ceramic powder may be at least one selected from the group consisting of Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , MgO · Al ₂ O ₃ , 2MgO · SiO ₂ , MgO · SiO ₂ , 2MgO · TiO ₂ , MgO · TiO ₂ , MgO · 2TiO ₂ , Al _{2 O 3 · SiO 2, 3Al} 2 O 3 · 2SiO 2, Al 2 O 3 · TiO 2, ZnO · SiO 2, ZrO 2 · SiO 2, ZrO 2 · TiO 2, 9Al 2 O 3 · 2B 2 O 3, _{2Al 2 O 3 · B 2 O} 3, 2MgO · 2Al 2 O 3 · 5SiO 2, Li 2 O · Al 2 O 3 · SiO 2, Li 2 O · Al 2 O 3 · 4SiO 2, BaO · Al 2 O 3 _{· SiO 2, AlN, SiC,} TiC, TiN, BN, ZrN, CrN, BaTiO 3, SrTiO 3, FeTiO 3, MgTiO 3, CaO, FeAl 2 O 4, CaTiO 3, MgAl 2 O 4, FeTiO 4, SrZrO 3 , Y ₂ O ₃ , CoAl ₂ O ₄ , and ZrSiO ₄ .

The particle size of the ceramic powder may be 10 to 1000 nm. If the particle size of the ceramic powder is too small, the formation of the ceramic layer may become difficult. If the particle diameter of the ceramic powder is too large, the surface roughness may become coarse and surface defects may occur. Therefore, the particle diameter of the ceramic powder can be adjusted to the above-mentioned range.

The ceramic powder may be in the form of any one or more selected from the group including spherical, plate-like, and needle-shaped.

At this time, the ceramic layer 30 on the line can be formed by spraying the ceramic powder at an angle (?) Of 82 to 88 ° or 92 to 98 ° with respect to the rolling direction. Further, a plurality of ceramic layers may be formed, and a plurality of ceramic layers may form a pattern along the rolling direction of the steel sheet.

The ceramic layer 30 on the line is the same as that of the grain-oriented electrical steel sheet, and a duplicate description will be omitted.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. However, the following examples are only a preferred embodiment of the present invention, and the present invention is not limited to the following examples.

Experimental Example  One

, 0.04 wt% of antimony (Sb), 0.09 wt% of tin (Sn), and nickel (Ni) were added in an amount of 3.4 wt% of silicon (Si), 0.03 wt% of aluminum (Al) 0.02 wt% of carbon (C), 0.06 wt% of carbon (C) and 40 wt% of nitrogen (N), and the balance of Fe and other unavoidable impurities.

The slab was heated at 1150 占 폚 for 220 minutes and hot-rolled to a thickness of 2.3 mm to prepare a hot-rolled steel sheet.

The hot-rolled steel sheet was heated to 1120 占 폚, held at 920 占 폚 for 95 seconds, quenched in water and pickled, and cold-rolled to a thickness of 0.27 mm to prepare a cold-rolled sheet.

The cold-rolled sheet was placed in a furnace maintained at 850 캜, maintained in a mixed atmosphere of 74% by volume of hydrogen, 25% by volume of nitrogen and 1% by volume of dry ammonia gas for 180 seconds, Annealing were simultaneously carried out to produce a primary recrystallized annealed steel sheet. An annealing separator containing magnesium oxide (MgO) as a main component was applied to a steel sheet subjected to primary recrystallization annealing using a roll, followed by secondary recrystallization annealing.

The primary and secondary cracking temperatures were set to 700 ° C and 1200 ° C, respectively, during the second recrystallization annealing, and to 15 ° C / hr during the temperature rise period. In addition, up to 1200 deg. C, a mixed gas atmosphere of 50 vol% nitrogen and 50 vol% hydrogen was set. After reaching 1200 deg. C, it was maintained in a hydrogen gas atmosphere of 100 vol% for 20 hours and then furnace cooled.

Thereafter, ceramic powder was supplied to a heat source in which argon (Ar) gas was converted into plasma at an output of 250 kW, and was sprayed at an angle (?) Set forth in Table 1 below. The spacing of the ceramic layers was 4.5 mm, the width was 9 mm, and the thickness was 0.6 占 퐉.

The magnetostriction generates a sinusoidal magnetic field of one cycle and converts the magnetostriction of the time domain into a log scale through Fourier transform to obtain A-weighted decibels. And the frequency responses are summarized in Table 1 below.

Noise was measured by real - time monitoring by installing a microphone on the top of the directional electric steel plate.

The iron loss was measured at 1.7 Tesla and 50 Hz using a single sheet method and the magnetic flux density (Tesla) induced under a magnetic field of 800 A / m was measured. Each iron loss value represents the average by condition. The magnetic flux density and iron loss are summarized in Table 1 below.

division Angle (β, °) Ceramic type Measuring condition: 1.7T 50Hz Magnetostriction
(? PP, nm) Noise (λdBA, dBA) W17 / 50 (W / kg) B8 (T) Comparative Example 1 No ceramic layer 1010 57.9 0.947 1.920 Comparative Example 2 90 TiO ₂ 325 55.3 0.848 1.918 Example 1 88 TiO ₂ 315 54.5 0.810 1.918 Example 2 86 TiO ₂ 248 52.7 0.770 1.920 Example 3 84 TiO ₂ 298 53.6 0.795 1.918 Example 4 82 TiO ₂ 318 55.0 0.840 1.918 Comparative Example 3 90 Y ₂ O ₃ 320 54.5 0.855 1.919 Example 5 88 Y ₂ O ₃ 308 53.2 0.802 1.918 Example 6 86 Y ₂ O ₃ 250 52.2 0.750 1.918 Example 7 84 Y ₂ O ₃ 277 53.2 0.790 1.917 Example 8 82 Y ₂ O ₃ 320 53.8 0.812 1.917

As shown in Table 1, it can be confirmed that the properties of Examples 1 to 8 are superior to those of Comparative Examples 1 to 3. It can be confirmed that this occurs because the ceramic layer has an appropriate angle (beta) with the rolling direction of the steel sheet.

Experimental Example  2

(Si), 0.03 wt% of aluminum (Al), 0.10 wt% of manganese (Mn), 0.05 wt% of antimony (Sb) and 0.05 wt% of tin (Sn) And other unavoidable impurities were prepared.

The slab was heated at 1150 占 폚 for 220 minutes and hot-rolled to a thickness of 2.3 mm to prepare a hot-rolled steel sheet.

The hot-rolled steel sheet was heated to 1120 占 폚, held at 920 占 폚 for 95 seconds, quenched in water and pickled, and then cold-rolled to a thickness of 0.23 mm to prepare a cold-rolled sheet.

The cold-rolled sheet was put into a furnace maintained at 850 ° C, and then the dew point temperature and the oxidizing ability were controlled. In the hydrogen, nitrogen, and ammonia mixed gas atmosphere, decarburization and primary recrystallization annealing were simultaneously performed, A steel sheet was produced.

Thereafter, slurry was prepared by mixing distilled water with an annealing separator containing MgO as a main component, and the slurry was applied to a decarburized annealed steel sheet using a roll or the like, and then finally annealed.

During the final annealing, the primary cracking temperature was 700 ° C, the secondary cracking temperature was 1200 ° C, and the temperature was 15 ° C / hr in the temperature rising period. In addition, the mixed gas atmosphere of nitrogen gas of 25 vol% and hydrogen gas of 75 vol% was heated up to 1200 deg. C, and after reaching 1200 deg. C, maintained in a hydrogen gas atmosphere of 100 vol% for 15 hours and then furnace cooling.

Thereafter, a ceramic powder was injected into a heat source in which argon (Ar) gas was converted into plasma at an output of 200 kW. On the metal oxide layer, a ceramic layer having an angle? Formed by the linear ceramic layer and the rolling direction of 86 占 was formed to a thickness of 1.5 占 퐉 at a coating width of 10 mm and a coating distance of 5 mm.

division Ceramic powder Magnetic property noise
(dBa) _{W 17/50 (W / kg} ) B ₈ (T) Example 9 Al ₂ O ₃ 0.70 1.930 43.2 Example 10 SiO ₂ 0.77 1.925 44.5 Example 11 ZrO ₂ 0.72 1.915 44.5 Example 12 MgO · Al ₂ O ₃ 0.75 1.909 45.0 Example 13 MgO · SiO ₂ 0.78 1.917 45.1 Example 14 2MgO · TiO ₂ 0.75 1.920 46.2 Example 15 _{9Al 2 O 3 · 2B 2 O} 3 0.68 1.941 41 Example 16 BaTiO ₃ 0.77 1.920 45 Example 17 SrTiO ₃ 0.78 1.915 46 Example 18 FeTiO ₃ 0.85 1.923 50 Example 19 MgTiO ₃ 0.81 1.908 51 Example 20 CaO 0.83 1.900 49 Example 21 FeAl ₂ O ₄ 0.83 1.901 50

As shown in Table 2, it can be seen that excellent magnetic and noise reduction characteristics are exhibited irrespective of the type of the ceramic powder.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: directional electric steel plate, 10: base steel plate,
20: metal oxide layer, 30: ceramic layer

Claims (18)

Base steel sheet; And
And a linear ceramic layer positioned on the base steel sheet,
Wherein the on-line ceramic layer has an angle of 82 to 88 ° or 92 to 98 ° with the rolling direction of the steel sheet. The method according to claim 1,
Wherein a plurality of the on-line ceramic layers are present, and a plurality of ceramic layers form a pattern along the rolling direction of the steel sheet. The method according to claim 1,
Wherein the ceramic layer has a width of 5.0 to 30 mm. 3. The method of claim 2,
Wherein a distance between the ceramic layers is 2.0 to 10.0 mm. The method according to claim 1,
Wherein the ceramic layer has a porosity of 1% or less. The method according to claim 1,
Wherein the ceramic layer has a surface roughness of 1 占 퐉 or less. The method according to claim 1,
Wherein the ceramic layer has a thickness of 0.1 to 3.5 占 퐉. The method according to claim 1,
Wherein the ceramic layer is made of ceramic powder. 9. The method of claim 8,
The ceramic powder may include at least one selected from Li, B, Ca, Sr, Mg, Al, Si, P, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Wherein the oxide, nitride, carbide, or oxynitride is contained. 9. The method of claim 8,
The ceramic powder may be selected from the group consisting of Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , MgO · Al ₂ O ₃ , 2MgO · SiO ₂ , MgO · SiO ₂ , 2MgO · TiO ₂ , MgO · TiO ₂ , MgO · 2TiO ₂ , _{Al 2 O 3 · SiO 2,} 3Al 2 O 3 · 2SiO 2, Al 2 O 3 · TiO 2, ZnO · SiO 2, ZrO 2 · SiO 2, ZrO 2 · TiO 2, 9Al 2 O 3 · 2B 2 O 3 _{, 2Al 2 O 3 · B 2} O 3, 2MgO · 2Al 2 O 3 · 5SiO 2, Li 2 O · Al 2 O 3 · SiO 2, Li 2 O · Al 2 O 3 · 4SiO 2, BaO · Al 2 O _{3 · SiO 2, AlN, SiC} , TiC, TiN, BN, ZrN, CrN, BaTiO 3, SrTiO 3, FeTiO 3, MgTiO 3, CaO, FeAl 2 O 4, CaTiO 3, MgAl 2 O 4, FeTiO 4, SrZrO ₃ , Y ₂ O ₃ , CoAl ₂ O ₄ , and ZrSiO ₄ . The method according to claim 1,
And a metal oxide layer formed between the base steel sheet and the ceramic layer. The method according to claim 1,
The base steel sheet comprises 2.6 to 5.5% by weight of silicon (Si), 0.020 to 0.040% by weight of aluminum (Al), 0.01 to 0.20% by weight of manganese (Mn), antimony (Sb) Wherein the composition comprises 0.01 to 0.15 wt% of the composition, the balance being Fe and other unavoidable impurities. Producing a base steel sheet; And
And forming a linear ceramic layer on said base steel sheet by spraying ceramic powder at an angle of 82 to 88 ° or 92 to 98 ° with respect to the rolling direction. 14. The method of claim 13,
The method of claim 1,
Producing a slab;
Heating the slab;
Hot-rolling the slab to produce a hot-rolled steel sheet;
Cold-rolling the hot-rolled steel sheet to produce a cold-rolled steel sheet;
Annealing the cold-rolled steel sheet for primary recrystallization annealing;
And secondary recrystallization annealing the primary recrystallized annealed steel sheet. 15. The method of claim 14,
Further comprising a step of applying an annealing separator after the primary recrystallization annealing step. 14. The method of claim 13,
In the step of forming the on-line ceramic layer,
A method of manufacturing a directional electrical steel sheet in which a plurality of ceramic layers are formed and a plurality of ceramic layers form a pattern along the rolling direction of the steel sheet. 14. The method of claim 13,
Wherein forming the on-line ceramic layer comprises:
Supplying a ceramic powder to a heat source which has been plasmaized at a power of 20 to 300 kW with a gas containing at least one of Ar, H ₂ , N ₂ , and He, and spraying ceramic powders onto the ground steel sheet. &Lt; / RTI &gt; 14. The method of claim 13,
Wherein the average particle diameter of the ceramic powder is 10 to 1000 nm.

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