The present invention relates to grain-oriented electrical steel sheets, a method for manufacturing grain-oriented electrical steel sheets, and an annealing separator used for manufacturing grain-oriented electrical steel sheets.
Background technology
[0002]
The grain-oriented electrical steel sheet is a steel sheet in which Si is contained in an amount of about 0.5 to 7% by mass and the crystal orientation is integrated in the {110} <001> orientation (goss orientation). A catastrophic grain growth phenomenon called secondary recrystallization is used to control the crystal orientation.
[0003]
The manufacturing method of grain-oriented electrical steel sheet is as follows. The slab is heated and hot-rolled to produce a hot-rolled steel sheet. Anneal the hot-rolled steel sheet as needed. Pickle the hot-rolled steel sheet. A cold-rolled steel sheet is manufactured by cold-rolling the hot-rolled steel sheet after pickling at a cold-rolling ratio of 80% or more. Decarburization annealing is performed on the cold-rolled steel sheet to develop primary recrystallization. Finish annealing is performed on the cold-rolled steel sheet after decarburization annealing to develop secondary recrystallization. Through the above steps, grain-oriented electrical steel sheets are manufactured.
[0004]
After the above-mentioned decarburization annealing and before finish annealing, an aqueous slurry containing an annealing separator containing MgO as a main component is applied on the surface of the cold-rolled steel sheet and dried. After winding the cold-rolled steel sheet with the annealing separator dried on a coil, finish annealing is performed. During finish annealing, MgO in the annealing separator reacts with SiO 2 in the internal oxide layer formed on the surface of the cold-rolled steel sheet during decarburization annealing, and contains forsterite (Mg 2SiO 4) as the main component. A primary coating is formed on the surface. After forming the primary coating, an insulating coating (also referred to as a secondary coating) composed of, for example, colloidal silica and phosphate is formed on the primary coating. The primary coating and the insulating coating have a smaller coefficient of thermal expansion than the steel sheet. Therefore, the primary coating, together with the insulating coating, applies tension to the steel sheet to reduce iron loss. The primary coating further enhances the adhesion of the insulating coating to the steel sheet. Therefore, it is preferable that the primary coating has high adhesion to the steel sheet.
[0005]
On the other hand, it is also effective to increase the magnetic flux density to reduce the hysteresis loss in order to reduce the iron loss of the grain-oriented electrical steel sheet.
[0006]
In order to increase the magnetic flux density of the grain-oriented electrical steel sheet, it is effective to integrate the crystal orientation of the grain steel sheet in the Goss orientation. Techniques for enhancing the accumulation in the Goss direction are proposed in Patent Documents 1 to 3. In these patent documents, the steel sheet contains a magnetic property improving element (Sn, Sb, Bi, Te, Pb, Se, etc.) that enhances the action of the inhibitor. As a result, the accumulation in the Goss direction is increased, and the magnetic flux density can be increased.
[0007]
However, when the element for improving magnetic properties is contained, a part of the primary coating is aggregated, and the interface between the steel sheet and the primary coating tends to be flattened. In this case, the adhesion of the primary coating to the steel sheet is reduced.
[0008]
Patent Documents 4, 5, 6 and 7 disclose techniques for improving the adhesion of the primary coating to a steel sheet.
[0009]
In Patent Document 4, the slab contains 0.001 to 0.1% of Ce, and a primary film containing 0.01 to 1000 mg / m 2 of Ce is formed on the surface of the steel sheet. In Patent Document 5, in a grain-oriented electrical steel sheet containing Si: 1.8 to 7% and having a primary film containing forsterite as a main component on the surface, Ce is 0.001 per surface in the primary film in terms of basis weight. It contains ~ 1000 mg / m 2.
[0010]
In Patent Document 6, 0.1 to 10% of a rare earth metal element compound and one or more alkaline earth metal compounds selected from Ca, Sr or Ba are 0 in a quenching separator containing MgO as a main component. By containing a compound containing 1 to 10% and 0.01 to 5% of a sulfur compound, one or more alkaline earth metal compounds selected from Ca, Sr or Ba can be contained in the primary coating. It forms a primary film characterized by containing rare earth elements.
[0011]
Patent Document 7 is characterized by containing a compound containing one or more elements selected from Ca, Sr or Ba, a rare earth metal element compound of 0.1 to 1.0%, and sulfur. Form a primary coating.
Prior art literature
Patent documents
[0012]
Patent Document 1: Japanese Patent Application Laid-Open No. 6-88171
Patent Document 2: Japanese Patent Application Laid-Open No. 8-269552
Patent Document 3: Japanese Unexamined Patent Publication No. 2005-290446
Patent Document 4: Japanese Unexamined Patent Publication No. 2008-127634
Patent Document 5: Japanese Unexamined Patent Publication No. 2012-214902
Patent Document 6: International Publication No. 2008/062853
Patent Document 7: Japanese Unexamined Patent Publication No. 2009-270129
Outline of the invention
Problems to be solved by the invention
[0013]
However, when the annealing separator contains a rare earth element compound such as Y, La, or Ce to form a primary film containing Y, La, or Ce, the magnetic properties may deteriorate. Further, when preparing the quenching separator, if the number density of particles in the raw material powder of the rare earth element compound such as Y, La, Ce or the additive such as Ca, Sr, Ba is insufficient, the primary coating is formed. Areas of underdevelopment may occur, resulting in poor adhesion. Further, in the above document, there is no reference to the appearance of the film. In the grain-oriented electrical steel sheet, it is preferable that the film appearance is excellent.
[0014]
An object of the present invention is to manufacture a grain-oriented electrical steel sheet, a method for manufacturing a grain-oriented electrical steel sheet, and a grain-oriented electrical steel sheet, which have excellent magnetic properties, excellent adhesion of a primary film to a base steel sheet, and excellent film appearance. Is to provide an annealed separating agent utilized in.
Means to solve problems
[0015]
The grain-oriented electrical steel sheet according to the present invention comprises a group consisting of C: 0.005% or less, Si: 2.5 to 4.5%, Mn: 0.02 to 0.2%, S and Se in mass%. One or more elements to be selected: 0.005% or less in total, sol. It contains Al: 0.01% or less and N: 0.01% or less, and the balance is formed on the surface of the base steel plate having a chemical composition consisting of Fe and impurities, and Mg 2SiO. A primary coating containing 4 as a main component is provided, and the peak position of the Al emission intensity obtained when elemental analysis by the glow discharge emission analysis method is performed from the surface of the primary coating in the plate thickness direction of the directional electromagnetic steel plate is determined. It is an Al oxide that is arranged within the range of 2.0 to 10.0 μm in the plate thickness direction from the surface of the primary coating, and is an Al oxide at the peak position of Al emission intensity, and has an area-based circle equivalent diameter of 0.2 μm or more. The number density of the Al oxides is 0.032 to 0.20 / μm 2, and the distribution diagram of 100 μm × 100 μm Al oxides at the peak position of Al emission intensity obtained by the glow discharge emission analysis method. In the case of dividing by a grid of 10 μm × 10 μm, the ratio of the number of grids not containing Al oxide to the total number of grids in the distribution map is less than 5%.
[0016]
The method for manufacturing grain-oriented electrical steel sheets according to the present invention is from C: 0.1% or less, Si: 2.5 to 4.5%, Mn: 0.02 to 0.2%, S and Se in mass%. One or more elements selected from the group: 0.005-0.07% in total, sol. Cold with a cold rolling ratio of 80% or more with respect to a hot-rolled steel sheet containing Al: 0.005 to 0.05% and N: 0.001 to 0.030% and the balance being Fe and impurities. A process of producing a cold-rolled steel sheet to be a base steel sheet by rolling, a process of performing decarburization and annealing on the cold-rolled steel sheet, and a shrinking separator on the surface of the cold-rolled steel sheet after decarburization and annealing. A step of applying the contained aqueous slurry and drying the aqueous slurry on the surface of the cold-rolled steel sheet in a furnace at 400 to 1000 ° C., and a step of performing finish baking on the cold-rolled steel sheet after the aqueous slurry has been dried. And prepare. The quenching separator includes at least one metal compound selected from the group consisting of MgO, Y, La, and Ce, and at least one metal compound selected from the group consisting of Ti, Zr, and Hf. When the MgO content in the annealing separator is 100% by mass, the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide is The total content in terms of oxide of the metal compound selected from the group consisting of Ti, Zr, and Hf is 0.5 to 6.0%, and the total content in terms of oxide is 0.8 to 10.0%. The average particle size of the metal compound selected from the group consisting of La and Ce is 10 μm or less, and the average particle size of the metal compound selected from the group consisting of Ti, Zr and Hf is said to be Y, La and Ce. The ratio of the metal compound selected from the group consisting of the group to the average particle size is 0.1 to 3.0, and the total of the metal compounds selected from the group consisting of Y, La, and Ce in terms of oxide. The total of the content and the total content in terms of oxides of the metal compound selected from the group consisting of Ti, Zr, and Hf is 2.0 to 12.5%, and the quenching separator is used for the annealing. The ratio of the total number of Ti, Zr, and Hf atoms contained in the separating agent to the total number of Y, La, and Ce atoms is 0.15 to 3.6, and further, the Y, La, It is a metal compound particle selected from the group consisting of Ce, and has a sphere-equivalent diameter based on volume, and the number density of particles of 0.1 μm or more is 2 billion / g or more, and further, the Ti, It is a particle of a metal compound selected from the group consisting of Zr and Hf, and has a volume-based equivalent sphere diameter, and the number density of particles of 0.1 μm or more is 2 billion / g or more.
[0017]
The annealing separator used in the production of the directional electromagnetic steel plate according to the present invention contains at least one metal compound selected from the group consisting of MgO, Y, La, and Ce, and a group consisting of Ti, Zr, and Hf. It is selected from the group consisting of Y, La, and Ce when it contains at least one metal compound selected from the above and the MgO content in the annealing separator is 100% by mass. The total oxide-equivalent content of the metal compound is 0.5 to 6.0%, and the total oxide-equivalent content of the metal compound selected from the group consisting of Ti, Zr, and Hf is 0. 8 to 10.0%, the average particle size of the metal compound selected from the group consisting of Y, La, and Ce is 10 μm or less, and the average particle size of the metal selected from the group consisting of Ti, Zr, and Hf is 10 μm or less. The ratio of the average particle size of the compound to the average particle size of the metal selected from the group consisting of Y, La and Ce is 0.1 to 3.0, and the metal is selected from the group consisting of Y, La and Ce. The total of the oxide-equivalent total content of the metal compound to be obtained and the oxide-equivalent total content of the metal compound selected from the group consisting of Ti, Zr, and Hf is 2.0 to 12. It is 5%. The ratio of the total number of Ti, Zr, and Hf atoms contained in the quenching separator to the total number of Y, La, and Ce atoms is 0.15 to 3.6, and further, the Y, La , Ce, particles of a metal compound selected from the group consisting of, and having a volume-based sphere-equivalent diameter, and a particle number density of 0.1 μm or more is 2 billion / g or more, and further, the above-mentioned Ti. , Zr, Hf, which is a particle of a metal compound selected from the group, and has a volume-based equivalent sphere diameter, and the number density of particles of 0.1 μm or more is 2 billion / g or more.
The invention's effect
[0018]
The grain-oriented electrical steel sheet according to the present invention has excellent magnetic properties and excellent adhesion to the base steel sheet of the primary coating. The manufacturing method according to the present invention can manufacture the above-mentioned grain-oriented electrical steel sheet. The annealing separator according to the present invention is applied to the above-mentioned manufacturing method, whereby a grain-oriented electrical steel sheet can be manufactured.
Embodiment for carrying out the invention
[0019]
The present inventors have investigated and investigated the magnetic properties of grain-oriented electrical steel sheets containing elements for improving magnetic properties, and the adhesion of primary coatings formed by containing Y, La, and Ce compounds in a quenching separator. went. As a result, the present inventors obtained the following findings.
[0020]
The interface between the primary coating of grain-oriented electrical steel sheet and the steel sheet has an inset structure. Specifically, in the vicinity of the interface between the primary coating and the steel sheet, the roots of the primary coating are stretched inside the steel sheet. The more the root of the primary coating penetrates into the steel sheet, the higher the adhesion of the primary coating to the steel sheet. Further, the more the roots of the primary coating are dispersed inside the steel sheet (the more stretched it is), the higher the adhesion of the primary coating to the steel sheet is.
[0021]
On the other hand, if the roots of the primary coating penetrate too deeply into the steel sheet, the roots of the primary coating prevent secondary recrystallization in the Goss orientation. Therefore, crystal grains with random orientation increase in the surface layer. Furthermore, the root of the primary coating becomes a factor that hinders the movement of the domain wall, and the magnetism Qi characteristics deteriorate. Similarly, if the roots of the primary coating are excessively dispersed inside the steel sheet, the roots of the primary coating prevent the secondary recrystallization in the Goss orientation, so that the crystal grains in the random orientation increase in the surface layer. Further, the root of the primary coating becomes a factor that hinders the movement of the domain wall, and the magnetic characteristics deteriorate.
[0022]
Based on the above findings, the present inventors further investigated the state of the root of the primary coating, the magnetic properties of the grain-oriented electrical steel sheet, and the adhesion of the primary coating.
[0023]
When the annealing separator contains Y, La, and Ce compounds to form a primary film, the magnetic properties deteriorate as described above. It is considered that this is because the roots of the primary coating penetrate too deeply into the inside of the steel sheet and hinder the movement of the domain wall. Further, if the particle size of the Y, La, and Ce compounds is large, Y, La, and Ce are localized in the annealing separator. As a result, the roots of the primary coating do not grow uniformly, and there is a portion where the primary coating becomes thin. As a result, not only the film adhesion is deteriorated, but also the appearance of the film is deteriorated due to unevenness of light and darkness due to a bias in the degree of primary film development and color unevenness due to the formation of compounds containing Y, La, and Ce.
[0024]
Therefore, the present inventors reduce the content of the Y, La, and Ce compounds in the annealing separator containing MgO as the main component, and contain Ti, Zr, and Hf compounds as alternatives to form a primary film. At the same time, we tried to increase the density of the number of particles of these compounds in the quenching separator (raw material powder) before adjusting to the aqueous slurry. As a result, it has been found that the magnetic properties of the grain-oriented electrical steel sheet may be improved and the adhesion of the primary coating may be improved. The present inventors further adjusted the content of the Y, La, and Ce compounds and the content of the Ti, Zr, and Hf compounds in the MgO-based annealing separator to form the root depth of the primary coating. And the state of dispersion was investigated.
[0025]
The main component of the root of the primary film is an Al oxide typified by spinel (MgAl 2O 4). The depth position from the surface of the peak of Al emission intensity obtained by performing elemental analysis based on the glow discharge emission spectrometry (GDS method) from the surface of the directional electromagnetic steel plate in the plate thickness direction (hereinafter referred to as Al peak). The position D Al) is considered to indicate the position of the spinel, that is, the position of the root of the primary coating. Further, the number density of Al oxides represented by spinels having a diameter equivalent to a circle based on the area at the Al peak position D Al and having a size of 0.2 μm or more (hereinafter referred to as Al oxide number density ND) is the primary coating. It is considered to indicate the dispersed state of the roots.
[0026]
As a result of further studies, if the following conditions are met, the roots of the primary coating have an appropriate length and an appropriate dispersion state, so that excellent magnetic properties and adhesion of the primary coating can be obtained. Furthermore, it was found that the appearance of the film did not deteriorate.
(1) Al peak position D Al is 2.0 to 10.0 μm.
(2) The Al oxide number density ND is 0.032 to 0.20 / μm 2.
(3) In the distribution map of 100 μm × 100 μm Al oxide at the peak position of Al emission intensity obtained by the glow discharge emission analysis method, when the distribution map is divided by a grid of 10 μm × 10 μm, the total in the distribution map. The ratio of the number of lattices not containing Al oxide to the number of lattices (hereinafter referred to as lattice ratio RA Al) is less than 5%.
[0027]
The above-mentioned appropriate ranges of the Al peak position D Al, the Al oxide number density ND, and the lattice ratio RA Al are the average particle size of the Y, La, Ce compounds in the quenching separator, and the Y, La, Ce compounds. From the group consisting of Y, La, Ce in the raw material powder before adjusting the content, the average particle size of the Ti, Zr, Hf compounds, the content of the Ti, Zr, Hf compounds and the annealing separator into an aqueous slurry. It can be obtained by adjusting the number density of the particles of the selected metal compound and the number density of the particles of the metal compound selected from the group consisting of Ti, Zr, and Hf within an appropriate range.
[0028]
Further, the ratio of the oxide-equivalent content C RE (described later) of the Y, La, and Ce compounds and the oxide-equivalent content C G4 (described later) of the Ti, Zr, and Hf compounds in the MgO-based annealing separator. Al peak position D The image showing the distribution of Al obtained by EDS analysis in the glow discharge scar region of Al and the Al oxide number density ND (pieces / μm 2) in each image were investigated. As a result, the Al oxide number density ND changes by adjusting the oxide-equivalent content of the Y, La, and Ce compounds and the oxide-equivalent content of the Ti, Zr, and Hf compounds in the annealing separator. It turned out that.
[0029]
As a result of further studies, when MgO, Y, La, Ce compounds and Ti, Zr, Hf compounds are contained and the MgO content in the annealing separator is 100% by mass, Y, La, Ce. The total oxide-equivalent content of the compound is 0.5 to 6.0%, the total oxide-equivalent content of the Ti, Zr, and Hf compounds is 0.8 to 10.0%, and Y, La. , The average particle size of the Ce compound is 10 μm or less, and the ratio of the average particle size of the Ti, Zr, and Hf compounds to the average particle size of the Y, La, and Ce compounds is 0.1 to 3.0, and Y, La. , The total of the total oxide-equivalent content of the Ce compound and the total oxide-equivalent content of the Ti, Zr, and Hf compounds is 2.0 to 12.5%, and Ti, which is contained in the quenching separator. The ratio of the total number of Zr and Hf atoms to the total number of Y, La and Ce atoms is 0.15 to 3.6, and the compounding agent is contained in the raw material powder before being adjusted into an aqueous slurry. From the group consisting of the metal compound powder selected from the group consisting of Y, La, and Ce and the group consisting of Ti, Zr, and Hf, each of which has a density of 2 billion particles / g or more. A directional electromagnetic steel sheet manufactured from a hot-rolled steel sheet containing a magnetic flux density improving element (Sn, Sb, Bi, Te, Pb, etc.) by using a quenching separator to which a selected metal compound powder is applied. Also, the Al peak position D Al is 2.0 to 10.0 μm, and the number density ND of Al oxides with a size equivalent to 0.2 μm or more based on the area is 0.032 to 0.20 /. In the distribution map of 100 μm × 100 μm Al oxide at the peak position of Al emission intensity obtained by the glow discharge emission analysis method, the distribution map is divided into 10 μm × 10 μm grids. It was found that the ratio of the number of lattices containing no Al oxide (lattice ratio RA Al) to the total number of lattices in the compound was less than 5%, and excellent magnetic properties, adhesion of the primary coating, and good coating appearance were obtained. ..
[0030]
The grain-oriented electrical steel sheet according to the present invention completed based on the above findings has a mass% of C: 0.005% or less, Si: 2.5 to 4.5%, Mn: 0.02 to 0.2%. One or more elements selected from the group consisting of, S and Se: 0.005% or less in total, sol. It contains Al: 0.01% or less and N: 0.01% or less, and the balance is formed on the surface of the base steel sheet having a chemical composition consisting of Fe and impurities and the surface of the base steel sheet, and is Mg 2SiO. It is provided with a primary coating containing 4 as a main component. The peak position of the Al emission intensity obtained when elemental analysis by the glow discharge emission analysis method is performed from the surface of the primary coating in the plate thickness direction of the directional electromagnetic steel plate is 2.0 to the plate thickness direction from the surface of the primary coating. Al arranged within the range of 10.0 μm, the number density of Al oxides at the peak position of Al emission intensity is 0.032 to 0.2 / μm 2, and Al obtained by the glow discharge emission analysis method. In the distribution map of 100 μm × 100 μm Al oxide at the peak position of emission intensity, when the distribution map is divided by 10 μm × 10 μm grids, the ratio of the number of grids not including Al oxide to the total number of grids in the distribution map is It is less than 5%.
[0031]
The method for manufacturing grain-oriented electrical steel sheets according to the present invention is from C: 0.1% or less, Si: 2.5 to 4.5%, Mn: 0.02 to 0.2%, S and Se in mass%. One or more elements selected from the group: 0.005-0.07% in total, sol. Cold with a cold rolling ratio of 80% or more with respect to a hot-rolled steel sheet containing Al: 0.005 to 0.05% and N: 0.001 to 0.030% and the balance being Fe and impurities. A process of producing a cold-rolled steel sheet to be a base steel sheet by rolling, a process of performing decarburization and annealing on the cold-rolled steel sheet, and a shrinking separator on the surface of the cold-rolled steel sheet after decarburization and annealing. A step of applying the contained aqueous slurry and drying the aqueous slurry on the surface of the cold-rolled steel sheet in a furnace at 400 to 1000 ° C., and a step of performing finish baking on the cold-rolled steel sheet after the aqueous slurry has been dried. And prepare. The annealing separator is at least one metal compound selected from the group consisting of MgO, Y, La, and Ce, and at least one metal compound selected from the group consisting of Ti, Zr, and Hf. When the above is contained and the MgO content in the annealing separator is 100% by mass, the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide is 0. It is 5 to 6.0%, and the total content in terms of oxide of the metal compound selected from the group consisting of Ti, Zr and Hf is 0.8 to 10.0%, from Y, La and Ce. The average particle size of the metal compound selected from the group is 10 μm or less, and the average particle size of the metal compound selected from the group consisting of Ti, Zr, and Hf is selected from the group consisting of Y, La, and Ce. The ratio of the metal compound to the average particle size is 0.1 to 3.0, and the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide and Ti, Zr, Hf. The total of the total content of the metal compound selected from the group consisting of metal compounds in terms of oxide is 2.0 to 12.5%, and in the annealing separator, Ti, Zr, contained in the annealing separator. The ratio of the total number of Hf atoms to the total number of Y, La, and Ce atoms is 0.15 to 3.6, and further, in the raw material powder before adjusting the quenching separator into the aqueous slurry. The number of particles of the metal compound having a particle size of 0.1 μm or more selected from the group consisting of Y, La, and Ce, and the particles having a particle size of 0.1 μm or more of the metal compound selected from the group consisting of Ti, Zr, and Hf. The number density of each is 2 billion pieces / g or more. However, the particle size is the equivalent diameter of a sphere on a volume basis.
[0032]
The annealing separator further contains at least one metal compound selected from the group consisting of Ca, Sr, and Ba, and when the MgO content in the annealing separator is 100% by mass, Ca, The total content of the metal compound selected from the group consisting of Sr and Ba in terms of sulfate may be 10% or less.
[0033]
In the method for producing a directional electromagnetic steel sheet, the chemical composition of the hot-rolled steel sheet further comprises 0. It may contain 6% or less.
[0034]
In the method for producing a directional electromagnetic steel sheet, the chemical composition of the hot-rolled steel sheet further comprises 0. It may contain 03% or less.
[0035]
The annealing separator according to the present invention is used in the production of grain-oriented electrical steel sheets. The quenching separator includes at least one metal compound selected from the group consisting of MgO, Y, La, and Ce, and at least one metal compound selected from the group consisting of Ti, Zr, and Hf. When the MgO content in the annealing separator is 100% by mass, the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide is 0.5. The total content in terms of oxide of the metal compound selected from the group consisting of Ti, Zr, and Hf is 0.8 to 10.0%, and it is composed of Y, La, and Ce. The average particle size of the metal compound selected from the group is 10 μm or less, and the average particle size of the metal compound selected from the group consisting of Ti, Zr, and Hf is selected from the group consisting of Y, La, and Ce. The ratio of the metal compound to the average particle size is 0.1 to 3.0, and the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide and Ti, Zr, and Hf. The total of the total content of the metal compound selected from the group in terms of oxide is 2.0 to 12.5%, and Ti, Zr, Hf contained in the quenching separator. The ratio of the total number of atoms to the total number of Y, La, and Ce atoms is 0.15 to 3.6, and Y in the raw material powder before the quenching separator is adjusted into the aqueous slurry. , The number of particles of the metal compound having a particle size of 0.1 μm or more selected from the group consisting of La and Ce, and the particles of the metal compound having a particle size of 0.1 μm or more selected from the group consisting of Ti, Zr and Hf. The number density is 2 billion pieces / g or more. However, the particle size is the equivalent diameter of a sphere on a volume basis.
[0036]
The annealing separator further contains at least one metal compound selected from the group consisting of Ca, Sr, and Ba, and when the MgO content in the annealing separator is 100% by mass, Ca, The total content of the metal selected from the group consisting of Sr and Ba in terms of sulfate may be 10% or less.
[0037]
Hereinafter, the method for manufacturing grain-oriented electrical steel sheets and grain-oriented electrical steel sheets according to the present invention, and the annealing separator used for manufacturing grain-oriented electrical steel sheets will be described in detail. In the present specification,% with respect to the content of an element means mass% unless otherwise specified. Further, regarding the numerical values ​​A and B, the notation "A to B" means "A or more and B or less". When a unit is attached only to the numerical value B in such a notation, the unit shall be applied to the numerical value A as well.
[0038]
[Structure of grain-oriented electrical steel sheet]
The grain-oriented electrical steel sheet according to the present invention includes a base steel sheet and a primary coating formed on the surface of the base steel sheet.
[0039]
[Chemical composition of base steel sheet]
The chemical composition of the base steel sheet constituting the above-mentioned grain-oriented electrical steel sheet contains the following elements. As will be described in the manufacturing method described later, the base steel sheet is manufactured by performing cold rolling using a hot-rolled steel sheet having a chemical composition described later.
[0040]
C: 0.005% or less
Carbon (C) is an element effective for microstructure control until the decarburization annealing process is completed during the manufacturing process, but if the C content exceeds 0.005%, the magnetic properties of the grain-oriented electrical steel sheet, which is the product plate, Decreases. Therefore, the C content is 0.005% or less. The C content is preferably as low as possible. However, even if the C content is reduced to less than 0.0001%, the above effect does not change so much, only the manufacturing cost is incurred. Therefore, the preferred lower limit of the C content is 0.0001%.
[0041]
Si: 2.5-4.5%
Silicon (Si) increases the electrical resistance of steel and reduces eddy current loss. If the Si content is less than 2.5%, the above effect cannot be sufficiently obtained. On the other hand, if the Si content exceeds 4.5%, the cold workability of the steel deteriorates. Therefore, the Si content is 2.5-4.5%. The lower limit of the Si content is preferably 2.6%, more preferably 2.8%. The preferred upper limit of the Si content is 4.0%, more preferably 3.8%.
[0042]
Mn: 0.02 to 0.20%
Manganese (Mn) combines with S and Se described later to form MnS and MnSe during the manufacturing process. These precipitates function as inhibitors (inhibitors of normal grain growth) and cause secondary recrystallization in steel. Mn further enhances the hot workability of steel. If the Mn content is less than 0.02%, the above effect cannot be sufficiently obtained. On the other hand, if the Mn content exceeds 0.20%, secondary recrystallization does not occur and the magnetic properties of the steel deteriorate. Therefore, the Mn content is 0.02 to 0.20%. The preferred lower limit of the Mn content is 0.03%, more preferably 0.04%. The preferred upper limit of the Mn content is 0.13%, more preferably 0.10%.
[0043]
One or more elements selected from the group consisting of S and Se: 0.005% or less in total
Sulfur (S) and selenium (Se) combine with Mn to form MnS and MnSe that function as inhibitors during the manufacturing process. However, if the total content of these elements exceeds 0.005%, the remaining inhibitors will reduce the magnetic properties. Further, segregation of S and Se may cause surface defects in the grain-oriented electrical steel sheet. Therefore, in the grain-oriented electrical steel sheet, the total content of one or more selected from the group consisting of S and Se is 0.005% or less. It is preferable that the total S and Se contents in the grain-oriented electrical steel sheet are as low as possible. However, even if the total of the S content and the Se content in the grain-oriented electrical steel sheet is reduced to less than 0.0005%, only the manufacturing cost increases and the above effect does not change so much. Therefore, the preferable lower limit of the total content of one or more selected from the group consisting of S and Se in the grain-oriented electrical steel sheet is 0.0005%.
[0044]
Sol. Al: 0.01% or less
Aluminum (Al) combines with N to form AlN during the manufacturing process of grain-oriented electrical steel sheets, and functions as an inhibitor. However, sol. If the Al content exceeds 0.01%, the inhibitor remains excessively in the steel sheet, so that the magnetic properties deteriorate. Therefore, sol. The Al content is 0.01% or less. sol. The preferred upper limit of the Al content is 0.004%, more preferably 0.003%. sol. It is preferable that the Al content is as low as possible. However, sol. Reducing the Al content to less than 0.0001% only increases the manufacturing cost and does not significantly change the above effect. Therefore, sol. In the grain-oriented electrical steel sheet. The preferable lower limit of the Al content is 0.0001%. In addition, in this specification, sol. Al means acid-soluble Al. Therefore, sol. The Al content is the content of acid-soluble Al.
[0045]
N: 0.01% or less
Nitrogen (N) combines with Al to form AlN during the manufacturing process of grain-oriented electrical steel sheets, and functions as an inhibitor. However, if the N content in the grain-oriented electrical steel sheet exceeds 0.01%, the inhibitor remains excessively in the grain-oriented electrical steel sheet, so that the magnetic properties deteriorate. Therefore, the N content is 0.01% or less. The preferred upper limit of the N content is 0.004%, more preferably 0.003%. The N content is preferably as low as possible. However, even if the total N content in the grain-oriented electrical steel sheet is reduced to less than 0.0001%, the manufacturing cost is only increased and the above effect does not change so much. Therefore, the preferable lower limit of the N content in the grain-oriented electrical steel sheet is 0.0001%.
[0046]
The balance of the chemical composition of the base steel sheet of the grain-oriented electrical steel sheet according to the present invention consists of Fe and impurities. Here, impurities are those mixed from ore, scrap, or the manufacturing environment as a raw material when the base steel sheet is industrially manufactured, or are not completely purified by purification annealing and are contained in the steel. It means the following remaining elements and the like that are permissible as long as they do not adversely affect the grain-oriented electrical steel sheet of the present invention.
[0047]
[About impurities]
The total content of one or more elements selected from the group consisting of Cu, Sn, Sb, Bi, Te and Pb in the impurities in the base steel sheet of the directional electromagnetic steel sheet according to the present invention is 0.30% or less. be.
[0048]
Copper (Cu), tin (Sn), antimony (Sb), bismuth (Bi), tellurium (Te) and lead (Pb) are used in the base steel plate by high-temperature heat treatment, which is also called "purification annealing" in one process of finish annealing. A part of Cu, Sn, Sb, Bi, Te and Pb in the system is discharged to the outside of the system. These elements exert the effect of increasing the orientation selectivity of secondary recrystallization and improving the magnetic flux density in the finish annealing, but if they remain in the grain-oriented electrical steel sheet after the finish annealing is completed, they deteriorate the iron loss as mere impurities. .. Therefore, the total content of one or more elements selected from the group consisting of Cu, Sn, Sb, Bi, Te and Pb is 0.30% or less. As described above, since these elements are impurities, it is preferable that the total content of these elements is as low as possible.
[0049]
[Primary coating]
The grain-oriented electrical steel sheet according to the present invention further includes a primary coating as described above. The primary coating is formed on the surface of the base steel sheet. The main component of the primary coating is forsterite (Mg 2SiO 4). More specifically, the primary coating contains 50-90% by mass of Mg 2SiO 4.
[0050]
The main component of the primary coating is Mg 2SiO 4 as described above, but the primary coating also contains Y, La, Ce and Ti, Zr, Hf. The total Y, La, and Ce contents in the primary coating are 0.001 to 6.0%. The total content of Ti, Zr, and Hf in the primary coating is 0.0005 to 4.0%.
[0051]
As described above, in the present invention, in the method for producing grain-oriented electrical steel sheets, an annealing separator containing Ti, Zr, and Hf compounds is used in addition to the above-mentioned Y, La, and Ce compounds. As a result, the magnetic properties of the grain-oriented electrical steel sheet can be enhanced, and the film adhesion of the primary coating can also be enhanced. Since Y, La, Ce and Ti, Zr, Hf are contained in the annealing separator, the primary coating also contains the above-mentioned contents of Y, La, Ce and Ti, Zr, Hf.
[0052]
The Mg 2SiO 4 content in the primary coating can be measured by the following method. The grain-oriented electrical steel sheet is electrolyzed to separate the primary coating unit from the surface of the base steel sheet. Mg in the separated primary film is quantitatively analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The product of the obtained quantitative value (mass%) and the molecular weight of Mg 2SiO 4 is divided by the atomic weight of Mg to obtain the content of Mg 2SiO 4 equivalent.
[0053]
The total Y, La, Ce content and the total Ti, Zr, Hf content in the primary coating can be measured by the following method. The grain-oriented electrical steel sheet is electrolyzed to separate the primary coating unit from the surface of the base steel sheet. Y content (mass%), La content (mass%), Ce content (mass%), Ti content (mass%), Zr content (mass%) and Hf content in the separated primary film. (% by mass) is quantitatively analyzed by ICP-MS to obtain the total of Y content, La content, Ce content and the total of Ti content, Zr content and Hf content.
[0054]
[Peak position of Al emission intensity by GDS method]
Further, in the directional electromagnetic steel plate according to the present invention, the peak position of the Al emission intensity obtained when elemental analysis by the glow discharge emission spectrometry is performed in the plate thickness direction of the directional electromagnetic steel plate from the surface of the primary coating is the primary coating. It is arranged within the range of 2.0 to 10.0 μm in the plate thickness direction from the surface.
[0055]
In grain-oriented electrical steel sheets, the interface between the primary coating and the steel sheet (bare metal) has an inset structure. Specifically, a part of the primary coating penetrates into the inside of the steel sheet from the surface of the steel sheet. A part of the primary coating that has entered the inside of the steel sheet from the surface of the steel sheet exerts a so-called anchor effect and enhances the adhesion of the primary coating to the steel sheet. Hereinafter, in the present specification, a part of the primary coating that has entered the inside of the steel sheet from the surface of the steel sheet is defined as "the root of the primary coating".
[0056]
In the region where the roots of the primary coating penetrate deeply into the steel sheet, the main component of the roots of the primary coating is spinel (MgAl 2O 4), which is a kind of Al oxide. The peak of the Al emission intensity obtained when the elemental analysis by the glow discharge emission spectrometry is performed indicates the position of the spinel.
[0057]
The depth position of the Al emission intensity peak from the surface of the primary coating is defined as the Al peak position D Al (μm). Al peak position D When Al is less than 2.0 μm, it means that the spinel is formed at a shallow (low) position from the surface of the steel sheet. This means that the roots of the primary coating are shallow. In this case, the adhesion of the primary coating is low. On the other hand, when the Al peak position D Al exceeds 10.0 μm, the roots of the primary coating are excessively developed, and the roots of the primary coating have penetrated to the deep part inside the steel sheet. In this case, the root of the primary coating inhibits the domain wall movement. As a result, the magnetic properties deteriorate.
[0058]
Al peak position D If Al is 2.0 to 10.0 μm, the adhesion of the coating film can be improved while maintaining excellent magnetic properties. Al peak position D The preferable lower limit of Al is 3.0 μm. It is more preferably 4.0 μm. Al peak position D The preferable upper limit of Al is 9.0 μm, and more preferably 8.0 μm.
[0059]
Al peak position D Al can be measured by the following method. Elemental analysis is performed using a well-known glow discharge emission spectrometry (GDS method). Specifically, an Ar atmosphere is created on the surface of the grain-oriented electrical steel sheet. A voltage is applied to the grain-oriented electrical steel sheet to generate glow plasma, and the surface layer of the steel sheet is sputtered and analyzed in the plate thickness direction.
[0060]
Al is identified in the surface layer of the steel sheet based on the emission spectrum wavelength peculiar to the element generated by exciting atoms in glow plasma. In addition, the emission intensity of the identified Al is plotted in the depth direction. Based on the plotted Al emission intensity, the Al peak position D Al is obtained.
[0061]
The depth position from the surface of the primary coating in elemental analysis can be calculated based on the spatter time. Specifically, the relationship between the spatter time and the spatter depth (hereinafter referred to as the sample result) is obtained in advance in the standard sample. The sample results are used to convert the sputter time to sputter depth. The converted sputter depth is defined as the depth position (depth position from the surface of the primary coating) subjected to elemental analysis (Al analysis). In the GDS method in the present invention, a commercially available high frequency glow discharge emission spectrometer can be used.
[0062]
[Number density ND of Al oxides with a size of 0.2 μm or more in discharge marks]
Further, in the directional electromagnetic steel plate according to the present invention, the number density ND of Al oxides having a diameter equivalent to a circle at the Al peak position D Al and having a size of 0.2 μm or more is 0.032 to 0.20 / μm 2. Is.
[0063]
As described above, the Al peak position D Al corresponds to the root portion of the primary coating. Spinel (MgAl 2O 4), which is an Al oxide, is abundantly present in the roots of the primary coating. Therefore, when the number density of Al oxides in an arbitrary region at the Al peak position D Al (for example, the bottom of the discharge mark of the glow discharge) is defined as the Al oxide number density ND, the Al oxide number density ND is primary. It is an index showing the dispersed state of the root (spinel) of the coating film on the surface layer of the steel plate.
[0064]
When the Al oxide number density ND is less than 0.032 / μm 2, the roots of the primary coating are not sufficiently formed. Therefore, the uniformity of the primary coating is low. On the other hand, when the Al oxide number density ND exceeds 0.20 / μm 2, the roots of the primary coating are excessively developed, and the roots of the primary coating have penetrated to the deep part inside the steel sheet. In this case, the roots of the primary coating inhibit secondary recrystallization and domain wall movement, and the magnetic properties deteriorate. Therefore, the Al oxide number density ND is 0.032 to 0.20 / μm 2. The preferable lower limit of the Al oxide number density ND is 0.035 pieces / μm 2, and more preferably 0.04 pieces / μm 2. The preferable upper limit of the number density ND is 0.12 pieces / μm 2, and more preferably 0.08 pieces / μm 2.
[0065]
The Al oxide number density ND can be obtained by the following method. Glow discharge is performed by the glow discharge emission spectrometer to the Al peak position D Al. Al peak position D Of the discharge marks at Al, elemental analysis using an energy dispersive X-ray spectroscope (EDS) is performed on an arbitrary region (observation region) of 30 μm × 50 μm or more, and the characteristics of the observation region. Create a map showing the distribution of X-ray intensity and identify Al oxides. Specifically, the region in which the intensity of the characteristic X-ray of O of 50% or more is analyzed with respect to the maximum intensity of the characteristic X-ray of O in the observation region is specified as an oxide. In the specified oxide region, a region in which the intensity of the specific X-ray of Al of 30% or more with respect to the maximum intensity of the specific X-ray of Al is analyzed is specified as an Al oxide. The identified Al oxide is mainly spinel, and may be a silicate containing Mg, Ca, Sr, Ba and the like and Al at a high concentration. Among the specified Al oxides, the number of Al oxides having a diameter equivalent to a circle based on the area and having a size of 0.2 μm or more is counted, and the Al oxide number density ND (pieces / μm 2) is obtained by the following formula. ..
Circle equivalent diameter = √ (4 / π ・ (Area of ​​region specified as Al oxide (area per analysis point in the map showing distribution of characteristic X-ray intensity x area specified as Al oxide) Analysis score))
Area per analysis point = observation area area ÷ number of analysis points in the map showing the distribution of characteristic X-ray intensity
ND = number of specified Al oxides with a circle equivalent diameter of 0.2 μm or more / area of ​​the observation area
[0066]
If the Y, La, Ce content in the primary coating is 0.001 to 6.0% and the Ti, Zr, Hf content in the primary coating is 0.0005 to 4.0%, the Al peak position. D Al is 2.0 to 10.0 μm, and the number density ND of Al oxides at the Al peak position D Al is 0.032 to 0.20 / μm 2.
[0067]
[Lattice ratio RA Al]
Further, in the directional electromagnetic steel plate according to the present invention, in the distribution map of Al oxide at the Al peak position D Al obtained by the glow discharge emission analysis method, the distribution map of 100 μm × 100 μm is divided by a grid of 10 μm × 10 μm and distributed. The ratio of the number of lattices not containing Al oxide (lattice ratio RA Al) to the total number of lattices in the figure is 5% or less.
[0068]
As described above, the Al peak position D Al corresponds to the root portion of the primary coating. Spinel (MgAl 2O 4), which is an Al oxide, is abundantly present in the roots of the primary coating. Therefore, the lattice ratio RA is an index indicating the dispersed state of the roots (Al oxide) of the primary coating on the surface layer of the steel sheet, as in the case of the Al oxide number density ND.
[0069]
When the lattice ratio RA Al exceeds 5%, the roots of the primary coating are not uniformly formed. Therefore, color unevenness occurs depending on the degree of development of the coating film, and the appearance of the coating film deteriorates. Therefore, the lattice ratio RA Al is 5% or less. The preferred upper limit of the lattice ratio RA is 3%, more preferably 2%.
[0070]
The lattice ratio RA Al can be obtained by the following method. Glow discharge is performed by the glow discharge emission spectrometer to the Al peak position D Al. Al peak position D Of the discharge marks at Al, an arbitrary 100 μm × 100 μm region (observation region) is subjected to elemental analysis using an energy dispersive X-ray spectroscope (EDS), and Al in the observation region is performed. Identify the oxide. Specifically, the region in which the intensity of the characteristic X-ray of O of 50% or more is analyzed with respect to the maximum intensity of the characteristic X-ray of O in the observation region is specified as an oxide. In the specified oxide region, a region in which the intensity of the specific X-ray of Al of 30% or more with respect to the maximum intensity of the specific X-ray of Al is analyzed is specified as an Al oxide. The identified Al oxide is mainly spinel, and may be a silicate containing Mg, Ca, Sr, Ba and the like and Al at a high concentration. Based on the measurement results, a distribution map of Al oxide in the observation region is created.
[0071]
The created distribution map is divided by a grid of 10 μm × 10 μm. Then, it is specified whether or not Al oxide is contained in each lattice. After identification, the number of lattices containing no Al oxide is counted. After obtaining the number of lattices containing no Al oxide, the lattice ratio RA Al (%) is calculated by the following formula.
Lattice ratio RA Al = number of lattices not including Al oxide / total number of lattices in the distribution map x 100
[0072]
[Production method]
An example of a method for manufacturing a grain-oriented electrical steel sheet according to the present invention will be described. An example of a method for manufacturing a grain-oriented electrical steel sheet includes a cold rolling step, a decarburization annealing step, and a finish annealing step. Hereinafter, each step will be described.
[0073]
[Cold rolling process]
In the cold-rolled process, cold-rolled steel sheets are cold-rolled to manufacture cold-rolled steel sheets. The hot-rolled steel sheet contains the following chemical composition.
[0074]
C: 0.1% or less,
If the C content in the hot-rolled steel sheet exceeds 0.1%, the time required for decarburization annealing becomes longer. In this case, the manufacturing cost is high and the productivity is also lowered. Therefore, the C content of the hot-rolled steel sheet is 0.1% or less. The preferred upper limit of the C content of the hot-rolled steel sheet is 0.092%, more preferably 0.085%. The lower limit of the C content of the rolled steel sheet is 0.005%, preferably 0.02%, and more preferably 0.04%.
[0075]
Si: 2.5-4.5%,
As explained in the section on chemical composition of grain-oriented electrical steel sheets, which is a product, Si increases the electrical resistance of steel, but if it is contained in excess, cold workability decreases. When the Si content of the hot-rolled steel sheet is 2.5 to 4.5%, the Si content of the grain-oriented electrical steel sheet after the finish annealing step is 2.5 to 4.5%. The upper limit of the Si content of the hot-rolled steel sheet is preferably 4.0%, more preferably 3.8%. The lower limit of the Si content of the hot-rolled steel sheet is preferably 2.6%, more preferably 2.8%.
[0076]
Mn: 0.02 to 0.20%
As explained in the item of chemical composition of grain-oriented electrical steel sheet which is a product, Mn combines with S and Se to form a precipitate and functions as an inhibitor in the manufacturing process. Mn further enhances the hot workability of steel. When the Mn content of the hot-rolled steel sheet is 0.02 to 0.20%, the Mn content of the directional electromagnetic steel sheet after the finish annealing step is 0.02 to 0.20%. The upper limit of the Mn content of the hot-rolled steel sheet is preferably 0.13%, more preferably 0.1%. The lower limit of the Mn content of the hot-rolled steel sheet is preferably 0.03%, more preferably 0.04%.
[0077]
One or more elements selected from the group consisting of S and Se: 0.005 to 0.07% in total
During the manufacturing process, sulfur (S) and selenium (Se) combine with Mn to form MnS and MnSe. Both MnS and MnSe function as inhibitors necessary for suppressing grain growth during secondary recrystallization. If the total content of one or more elements selected from the group consisting of S and Se is less than 0.005%, it is difficult to obtain the above effect. On the other hand, if the total content of one or more elements selected from the group consisting of S and Se exceeds 0.07%, secondary recrystallization does not occur during the manufacturing process and the magnetic properties of the steel deteriorate. .. Therefore, the total content of one or more elements selected from the group consisting of S and Se in the hot-rolled steel sheet is 0.005 to 0.07%. The preferred lower limit of the total content of one or more elements selected from the group consisting of S and Se is 0.008%, more preferably 0.016%. The preferred upper limit of the total content of one or more elements selected from the group consisting of S and Se is 0.06%, more preferably 0.05%.
[0078]
Sol. Al: 0.005 to 0.05%
During the manufacturing process, aluminum (Al) combines with N to form AlN. AlN functions as an inhibitor. Sol. In hot-rolled steel sheet. If the Al content is less than 0.005%, the above effect cannot be obtained. On the other hand, sol. If the Al content exceeds 0.05%, AlN becomes coarse. In this case, AlN becomes difficult to function as an inhibitor, and secondary recrystallization may not occur. Therefore, the sol. The Al content is 0.005 to 0.05%. Sol. In hot-rolled steel sheet. The preferred upper limit of the Al content is 0.04%, more preferably 0.035%. Sol. In hot-rolled steel sheet. The lower limit of the Al content is preferably 0.01%, more preferably 0.015%.
[0079]
N: 0.001 to 0.030%
During the manufacturing process, nitrogen (N) combines with Al to form AlN, which functions as an inhibitor. If the N content in the hot-rolled steel sheet is less than 0.001%, the above effect cannot be obtained. On the other hand, if the N content in the hot-rolled steel sheet exceeds 0.030%, AlN becomes coarse. In this case, AlN becomes difficult to function as an inhibitor, and secondary recrystallization may not occur. Therefore, the N content in the hot-rolled steel sheet is 0.001 to 0.030%. The preferable upper limit of the N content in the hot-rolled steel sheet is 0.012%, which is more preferable. Is 0.010%. The preferable lower limit of the N content in the hot-rolled steel sheet is 0.005%, more preferably 0.006%.
[0080] [0080]
The balance of the chemical composition of the hot-rolled steel sheet of the present invention consists of Fe and impurities. Here, the impurities are mixed from ore, scrap, manufacturing environment, etc. as a raw material when the hot-rolled steel sheet is industrially manufactured, and adversely affect the hot-rolled steel sheet of the present embodiment. Means something that is acceptable to the extent that it does not exist.
[0081]
[About arbitrary elements]
The hot-rolled steel sheet according to the present invention may further contain at least 0.6% of one or more elements selected from the group consisting of Cu, Sn and Sb instead of a part of Fe. All of these elements are arbitrary elements.
[0082]
One or more elements selected from the group consisting of Cu, Sn and Sb: 0 to 0.6% in total
Copper (Cu), tin (Sn) and antimony (Sb) are all optional elements and may not be contained. When contained, Cu, Sn and Sb all increase the magnetic flux density of grain-oriented electrical steel sheets. If Cu, Sn and Sb are contained even in a small amount, the above effect can be obtained to some extent. However, if the total contents of Cu, Sn and Sb exceed 0.6%, it becomes difficult to form an internal oxide layer during decarburization annealing. In this case, during finish annealing, MgO as an annealing separator and SiO 2 in the internal oxide layer react to delay the progress of primary film formation. As a result, the adhesion of the primary film is reduced. Further, Cu, Sn, and Sb are likely to remain as impurity elements after purification annealing. As a result, the magnetic properties deteriorate. Therefore, the total content of one or more elements selected from the group consisting of Cu, Sn and Sb is 0 to 0.6%. The preferred lower limit of the total content of one or more elements selected from the group consisting of Cu, Sn and Sb is 0.005%, more preferably 0.007%. The preferred upper limit of the total content of one or more elements selected from the group consisting of Cu, Sn and Sb is 0.5%, more preferably 0.45%.
[0083]
The hot-rolled steel sheet according to the present invention may further contain 0.03% or less in total of one or more elements selected from the group consisting of Bi, Te and Pb instead of a part of Fe. All of these elements are arbitrary elements.
[0084]
One or more elements selected from the group consisting of Bi, Te and Pb: 0 to 0.03% in total
Bismuth (Bi), tellurium (Te) and lead (Pb) are all optional elements and may not be contained. When contained, Bi, Te and Pb all increase the magnetic flux density of grain-oriented electrical steel sheets. If any of these elements are contained, this effect can be obtained to some extent. However, if the total content of these elements exceeds 0.03%, these elements segregate on the surface during finish annealing, and the interface between the primary coating and the steel sheet becomes flat. In this case, the film adhesion of the primary film is reduced. Therefore, the total content of one or more elements selected from the group consisting of Bi, Te and Pb is 0 to 0.03%. The preferred lower limit of the total content of one or more elements selected from the group consisting of Bi, Te and Pb is 0.0005%, more preferably 0.001%. The preferred upper limit of the total content of one or more selected from the group consisting of Bi, Te and Pb is 0.02%, more preferably 0.015%.
[0085]
The hot-rolled steel sheet having the above-mentioned chemical composition is manufactured by a well-known method. An example of a method for manufacturing a hot-rolled steel sheet is as follows. Prepare a slab having the same chemical composition as the hot-rolled steel sheet described above. Slabs are manufactured by performing well-known refining and casting processes. Heat the slab. The heating temperature of the slab is, for example, more than 1280 ° C to 1350 ° C. Hot rolling is performed on the heated slab to produce a hot-rolled steel sheet.
[0086]
Cold-rolled the prepared hot-rolled steel sheet to manufacture a cold-rolled steel sheet, which is the base steel sheet. Cold rolling may be carried out only once or may be carried out a plurality of times. When cold rolling is carried out a plurality of times, cold rolling is carried out, intermediate annealing for the purpose of softening is carried out, and then cold rolling is carried out. Cold rolling is carried out once or a plurality of times to produce a cold-rolled steel sheet having a product plate thickness (plate thickness as a product).
[0087]
The cold rolling ratio in one or more cold rolling is 80% or more. Here, the cold spread rate (%) is defined as follows.
Cold rolling ratio (%) = (1-Thickness of cold-rolled steel sheet after the last cold rolling / Thickness of hot-rolled steel sheet before the start of the first cold rolling) x 100
[0088]
The preferable upper limit of the cold spread rate is 95%. Further, the hot-rolled steel sheet may be heat-treated or pickled before the hot-rolled steel sheet is cold-rolled.
[0089]
[Decarburization annealing process]
Decarburization annealing is performed on the steel sheet manufactured by the cold rolling process, and nitriding annealing is performed as necessary. Decarburization annealing is performed in a well-known hydrogen-nitrogen-containing moist atmosphere. By decarburization annealing, the C concentration of grain-oriented electrical steel sheets is reduced to 50 ppm or less, which can suppress magnetic aging deterioration. In decarburization annealing, primary recrystallization is further developed in the steel sheet, and the processing strain introduced by the cold rolling step is released. Further, in the decarburization annealing step, an internal oxide layer containing SiO 2 as a main component is formed on the surface layer portion of the steel sheet. The annealing temperature in decarburization annealing is well known, for example, 750 to 950 ° C. The holding time at the annealing temperature is, for example, 1 to 5 minutes.
[Finishing annealing process]
Perform a finish annealing process on the steel sheet after the decarburization annealing process. In the finishing annealing step, first, an aqueous slurry containing an annealing separator is applied to the surface of the steel sheet. The coating amount is, for example, about 4 to 15 g / m 2 per side of a 1 m 2 steel sheet. Then, the steel sheet coated with the aqueous slurry is inserted into a furnace at 400 to 1000 ° C. and dried, and then annealing (finish annealing) is carried out.
[0090]
[About aqueous slurry]
The aqueous slurry is purified by adding industrial pure water to the annealing separator described later and stirring. The ratio of the annealing separator to the industrial pure water may be determined so as to be a required coating amount when coated with a roll coater, and is preferably 2 times or more and 20 times or less, for example. If the ratio of water to the annealing separator is less than twice, the viscosity of the water slurry becomes too high and the annealing separator cannot be uniformly applied to the surface of the steel sheet, which is not preferable. When the ratio of water to the annealing separator is more than 20 times, the water slurry is not sufficiently dried in the subsequent drying step, and the water remaining in the finish annealing further oxidizes the steel sheet, resulting in deterioration of the appearance of the primary coating film. Therefore, it is not preferable.
[0091]
[About annealing separator]
In the present invention, the annealing separator used in the finishing annealing step contains magnesium oxide (MgO) and an additive. MgO is the main component of the annealing separator, and the "main component" refers to a component contained in a substance in an amount of 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. .. The amount of the annealing separator adhered to the steel sheet is preferably 2 g / m 2 or more and 10 g / m 2 or less per one side, for example. When the amount of the annealing separator adhered to the steel sheet is less than 2 g / m 2, it is not preferable because the steel sheets are seized with each other in the finish annealing. If the amount of the annealing separator adhered to the steel sheet exceeds 10 g / m 2, the manufacturing cost increases, which is not preferable. The annealing separating agent may be applied by electrostatic application or the like instead of application by an aqueous slurry.
The additive contains at least one metal compound selected from the group consisting of Y, La, and Ce, and at least one metal compound selected from the group consisting of Ti, Zr, and Hf. When the MgO content in the quenching separator is 100% by mass, the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide is 0.5 to 6.0. %, And the total content of the metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide is 0.8 to 10.0%. Further, in the annealing separator, the ratio of the total number of Ti, Zr, and Hf atoms contained in the annealing separator to the total number of Y, La, and Ce atoms is 0.15 to 3.6. .. Further, in the annealing separator, the total content in terms of oxide of the metal compound selected from the group consisting of Y, La and Ce and the oxide of the metal compound selected from the group consisting of Ti, Zr and Hf. The total with the converted total content is 2.0 to 12.5%. Hereinafter, the additives in the annealing separator will be described in detail.
[0092]
[Additive]
The additive contains at least one metal compound selected from the group consisting of Y, La, and Ce and at least one metal compound selected from the group consisting of Ti, Zr, and Hf. The oxide-equivalent content of the metal compound selected from the group consisting of Y, La and Ce and the oxide-equivalent content of the metal compound selected from the group consisting of Ti, Zr and Hf are as follows. be.
[0093]
[Metal compound selected from the group consisting of Y, La, Ce]
The metal compounds (referred to as Y, La, Ce compounds) selected from the group consisting of Y, La and Ce have a total of 0. It contains 5 to 6.0%. Here, one kind of Y, La, and Ce compounds contained in the annealing separator is defined as M RE, and the oxide-equivalent content W RE (% by mass) of M RE in the annealing separator is as follows. It is as follows.
W RE = (MRE added amount (mass%)) / (MRE molecular weight) × ((Y2O3 molecular weight) × (Y atom number per MRE1 molecule / 2) + (La 2O3 molecular weight) × (Number of La atoms per M RE 1 molecule / 2) + (Molecular weight of CeO 2) × (Number of Ce atoms per M RE 1 molecule))
For the M RE, the ratio x RE of the total number of Y, La, and Ce atoms to the number of Mg atoms contained in the annealing separator is as follows.
x RE = ((the number of Y atoms per M RE molecule) + (the number of La atoms per M RE molecule) + (the number of Ce atoms per M RE molecule)) x (the amount of M RE added (mass%) ) / M RE molecular weight) × (MgO molecular weight / 100)
Therefore, the total content of Y, La, and Ce compounds in terms of oxides when the MgO content is 100% by mass in the annealing separator to which one or more Y, La, Ce compounds are added. Ratio of the total number of Y, La, Ce atoms to the number of Mg atoms in C RE (hereinafter referred to as oxide-equivalent content C RE of Y, La, Ce compound) and quenching separator X RE (hereinafter, Y, The abundance ratios of La and Ce atoms (referred to as X RE) are the sum of W RE and the sum of x RE of each of the metal compound species selected from the group consisting of Y, La and Ce contained in the quenching separator, respectively. Is.
[0094]
The Y, La, and Ce compounds are, for example, oxides and hydroxides, carbonates, sulfates, and the like that are partially or wholly converted into oxides by the drying treatment and finish annealing treatment described later. The Y, La, and Ce compounds suppress the aggregation of the primary coating. The Y, La, and Ce compounds also serve as oxygen release sources. Therefore, the root growth of the primary coating formed by finish annealing is promoted. As a result, the adhesion of the primary coating to the steel sheet is improved. If the oxide-equivalent content C RE of the Y, La, and Ce compounds is less than 0.5%, the above effect cannot be sufficiently obtained. On the other hand, if the oxide-equivalent content C RE of the Y, La, and Ce compounds exceeds 6.0%, the roots of the primary coating are excessively developed. In this case, the roots of the primary coating hinder the movement of the domain wall, so that the magnetic properties deteriorate. If the oxide-equivalent content C RE of the Y, La, and Ce compounds exceeds 6.0%, the MgO content in the annealing separator is further reduced, so that the formation of forsterite is suppressed. That is, the reactivity is reduced. Therefore, the oxide equivalent content C RE of the Y, La, and Ce compounds is 0.5 to 6.0%. The preferable lower limit of the oxide-equivalent content C RE of the Y, La, and Ce compounds is 1.0%, and more preferably 2.0%. Oxide conversion of Y, La, Ce compounds The preferred upper limit of the content C RE is 5.0%, more preferably 4.0%.
[0095]
The average particle size PS RE of the Y, La, and Ce compounds is 10 μm or less. When the average particle size PS RE of the Y, La, and Ce compounds exceeds 10 μm, the amount of the Y, La, and Ce compounds that react with Ti, Zr, and Hf decreases with respect to the addition amount, so that the root growth of the primary coating is performed. The promotion of the primary coating is suppressed, and the adhesion of the primary coating to the steel sheet is reduced. Further, the roots of the primary coating do not grow uniformly, and there is a portion where the primary coating becomes thin. As a result, the appearance of the film is deteriorated due to unevenness of light and darkness due to a bias in the degree of primary film development and color unevenness due to the formation of compounds containing Y, La, and Ce. Therefore, the average particle size PS RE is 10 μm or less. The preferred upper limit of the average particle size PS RE is 8 μm, more preferably 4 μm. The lower limit of the average particle size PS RE is not particularly limited, but is, for example, 0.003 μm or more in terms of industrial production.
[0096]
The average particle size PS RE can be measured by the following method. The Y, La, and Ce compound powders are measured by a laser diffraction / scattering method based on JIS Z8825 (2013) using a laser diffraction / scattering particle size distribution measuring device. Thereby, the average particle size PS RE can be obtained.
[0097]
[Metal compound selected from the group consisting of Ti, Zr, Hf]
Metal compounds (referred to as Ti, Zr, Hf compounds) selected from the group consisting of Ti, Zr, and Hf have a total of 0.8 to 0.8 in terms of oxide when MgO in the quenching separator is 100% by mass. It contains 10.0%. Here, one kind of Ti, Zr, Hf compound contained in the annealing separator is defined as MG4, and the oxide-equivalent content WG4 (mass%) of MG4 in the annealing separator is as follows. It is as follows.
W G4 = (Molecular weight of MG4 added (% by mass)) / (Molecular weight of MG4) × ((Molecular weight of TiO 2) × (Number of Ti atoms per MG41 molecule) + (Molecular weight of ZrO2) × (MG41) Number of Zr atoms per molecule) + (Molecular weight of HfO 2) × (Number of Hf atoms per MG41 molecule))
Further, for the MG4, the ratio of the total sum of Ti, Zr, and Hf atoms to the number of Mg atoms contained in the annealing separator x G4 is as follows.
x G4 = ((the number of Ti atoms per MG41 molecule) + (the number of Zr atoms per MG41 molecule) + (the number of Hf atoms per MG41 molecule)) x (the amount of MG4 added (mass%) ) / M G4 molecular weight) × (MgO molecular weight / 100)
Therefore, the total content of Ti, Zr, Hf compounds in terms of oxide when the MgO content is 100% by mass in the annealing separator to which one or more Ti, Zr, Hf compounds are added. C G4 (hereinafter referred to as oxide-equivalent content of Ti, Zr, Hf compound C G4) and the ratio of the total sum of Ti, Zr, Hf atoms to the number of Mg atoms in the quenching separator X G4 (hereinafter, Ti, Zr). , Hf atom abundance ratio X G4) is the sum of WG4 and x G4 of each metal compound selected from the group consisting of Ti, Zr, and Hf contained in the quenching separator, respectively.
[0098]
The Ti, Zr, and Hf compounds are, for example, oxides and hydroxides, carbonates, sulfates, etc., which are partially or wholly converted into oxides by the drying treatment and finish annealing treatment described later. When the Ti, Zr and Hf compounds are contained in the annealing separator together with the Y, La and Ce compounds, they react with a part of the Y, La and Ce compounds during finish annealing to form a composite oxide. If the composite oxide is formed, the oxygen release capacity of the annealing separator can be increased as compared with the case where the Y, La, and Ce compounds are contained alone. Therefore, by containing the Ti, Zr, and Hf compounds instead of the Y, La, and Ce compounds, the coating film grows homogeneously while suppressing the deterioration of the magnetic properties due to the excessive inclusion of the Y, La, and Ce compounds. However, the appearance of the coating film can be improved, the root growth of the primary coating film can be promoted, and the adhesion of the primary coating film to the steel sheet can be enhanced. If the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds is less than 0.8%, the above effect cannot be sufficiently obtained. On the other hand, if the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds exceeds 10.0%, the roots of the primary coating may be excessively developed and the magnetic properties may be deteriorated. If the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds exceeds 10.0%, the MgO content in the annealing separator is further reduced, so that the formation of forsterite is suppressed. That is, the reactivity is reduced. When the oxide equivalent content C G4 of the Ti, Zr, and Hf compounds is 0.8 to 10.0%, the primary coating adheres to the base steel sheet while suppressing the deterioration of magnetic properties and reactivity. It can enhance the sex.
[0099]
The preferable lower limit of the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds is 1.5%, and more preferably 2.0%. The preferable upper limit of the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds is 8.5%, and more preferably 8.0%.
[0100]
[Oxide-equivalent content of Y, La, Ce compounds C RE and total content of Oxide-equivalent content of Ti, Zr, Hf compounds C G4]
The total content of the oxide-equivalent content C RE of the Y, La, and Ce compounds and the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds is 2.0 to 12.5%. If the total content is less than 2.0%, the roots of the primary coating do not grow sufficiently, and the adhesion of the temporary coating to the steel sheet is lowered. On the other hand, if the total content exceeds 12.5%, the roots of the primary coating are excessively developed and the magnetic properties are deteriorated. Therefore, the total content of the oxide-equivalent content C RE of the Y, La, and Ce compounds and the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds is 2.0 to 12.5%. The preferred lower limit of the total content is 3.0%, and the preferred upper limit is 11.0%.
[0101]
[Average particle size ratio of Y, La, Ce compounds and Ti, Zr, Hf compounds in the annealing separator]
Ratio of average particle size PS G4 of Ti, Zr, Hf compounds to average particle size PS RE of Y, La, Ce compounds in the quenching separator (average particle size ratio) RA G4 / RE (= PS G4 / PS RE) ) Is 0.1 to 3.0.
[0102]
If the average particle size ratio RA G4 / RE is less than 0.1, the particle sizes of Ti, Zr, and Hf with respect to Y, La, and Ce are too small. In this case, the number of isolated Ti, Zr, and Hf compounds increases, and the development of the primary coating becomes non-uniform. As a result, the appearance of the film is deteriorated. On the other hand, when the average particle size ratio RA G4 / RE exceeds 3.0, the amount of the Y, La, and Ce compounds reacting with the Ti, Zr, and Hf compounds does not increase, and the development of the primary coating becomes non-uniform. As a result, the appearance of the film is deteriorated. When the average particle size ratio RA G4 / RE is 0.1 to 3.0, the appearance of the film is improved. The preferable lower limit of the average particle size ratio RA G4 / RE is 0.2, more preferably 0.3. The preferred upper limit of the average particle size ratio RA G4 / RE is 0.8, more preferably 0.6.
[0103]
The average particle size ratio RA G4 / RE is obtained by the following method. The average particle size PS RE is obtained by the above-mentioned measuring method. Further, the average particle size PS G4 of the Ti, Zr, and Hf compounds is obtained by the same measuring method as the average particle size PS RE. Using the obtained average particle size PS RE and PS G4, the average particle size ratio RA G4 / RE is obtained by the following formula.
Average particle size ratio RA G4 / RE = average particle size PS G4 / average particle size PS RE
[0104]
[Y, La, Ce atom / Ti, Zr, Hf atomic number ratio in the quenching separator]
In the annealing separator, the ratio (X RE / X G4) of the total number of Ti, Zr, and Hf atoms contained in the annealing separator to the total number of Y, La, and Ce atoms is 0.15. ~ 3.6. When X RE / X G4 is less than 0.15, the root growth of the primary coating is suppressed during finish annealing. As a result, the adhesion of the primary coating to the steel sheet is reduced. On the other hand, even if X RE / X G4 exceeds 3.6, the development of the primary coating becomes non-uniform and the appearance of the coating deteriorates. When X RE / X G4 is 0.15 to 3.6, the adhesion of the primary coating to the steel sheet is enhanced. The preferred lower limit of X RE / X G4 is 0.5, more preferably 0.8. The preferred upper limit of X RE / X G4 is 3.2, more preferably 3.0.
[0105]
[N RE and NG 4 in annealing separator]
If the number of particles of rare earth element compounds such as Y, La, and Ce and the number of particles of additives such as Ti, Zr, and Hf are insufficient in the powder of the raw material for the quenching separator before preparation into the aqueous slurry, the primary coating will be formed. Underdeveloped areas may occur, resulting in poor adhesion and film appearance. Therefore, the number of particles of the metal compound selected from the group consisting of Y, La, and Ce contained in the annealing separator and having a particle size of 0.1 μm or more is composed of the density NRE and Ti, Zr, Hf. The number density NG4 of the particles having a particle size of 0.1 μm or more of the selected metal compound is 2 billion pieces / g or more, respectively. The particle size of these metal compounds is determined as a volume-based equivalent sphere diameter, and is determined from a particle number-based particle size distribution obtained by measuring raw material powder with a laser diffraction type particle size distribution measuring device.
Here, the particle size distribution based on the number of particles is a particle size range in which an arbitrary value in the range of 0.1 to 0.15 μm is the minimum diameter and an arbitrary value in the range of 2000 to 4000 μm is the maximum diameter. It shows the frequency (%) of the particles in each section with respect to all particles after being divided by the same width on the logarithmic scale so as to have the above sections. Here, for the representative particle size D of each section, the upper limit value D MAX [μm] and the lower limit value D MIN [μm] of each section are used.
D = 10 ^ ((LogD MAX + LogD MIN) / 2)
Is required as.
Further, the weight w [g] of the particles in each section in the particles of 100 raw material powders is the abundance frequency f with respect to all the particles, the representative particle size D [μm], and the specific gravity d [g / μm 3] of the metal compound. make use of,
w = f ・ d ・ (D ^ 3 ・ π) / 6
Is required as.
Since the total W [g] of the weight w of all sections is the average weight of 100 raw material powder particles, the number of particles n [pieces / g] in 1 g of the metal compound powder is
N = 100 / W
Is required as.
When determining the number of particles of a metal compound having a particle size of 0.1 μm or more selected from the group consisting of Y, La, and Ce and the density N RE, the number of particles n in 1 g of each metal compound powder in the raw material powder. Is calculated, and the total content C (%) of the content c (%) of each metal compound in the slurry and all the content c is used.
N RE = Σ (n ・ c / C)
Is required as. The number density NG4 of particles having a particle size of 0.1 μm or more of a metal compound selected from the group consisting of Ti, Zr, and Hf is also obtained in the same manner.
If N RE or NG 4 is less than 2 billion pieces / g, the root growth effect of the primary coating is biased during finish annealing, and a region where root growth is not sufficiently promoted occurs. As a result, sufficient adhesion of the primary coating to the steel sheet cannot be obtained. When N RE and NG 4 are 2 billion pieces / g or more, the adhesion of the primary coating is enhanced. Y, La, Ce, Ti, Zr, Hf and the like have the effect of releasing oxygen during finish annealing, and Y, La, Ce slowly release oxygen from low temperature to high temperature. On the other hand, Ti, Zr, and Hf are considered to have a relatively short oxygen release period, but have the effect of enhancing the oxygen release effect of Y, La, and Ce, and sustain the aggregation of the internal oxide layer necessary for the development of the coating film. It is thought that it can be suppressed to. Therefore, it is considered that this interaction can be effectively obtained by increasing the number densities N RE and NG 4 to enhance the dispersed state in the separating agent layer.
[0106]
When N RE and NG 4 satisfy the above relationship, and when RA G4 / RE is 0.15 to 3.6, the development of the coating film becomes more remarkable and the appearance of the coating film becomes good. The reason for this is that when X RE / X G4 prepares a slurry in an appropriate range by making the particle size uniform, Ti, Zr, Hf are arranged in the vicinity of Y, La, Ce, and the acid. It is considered that the region where the elemental release is strengthened can be secured evenly with respect to the plate surface.
[0107]
On the other hand, if N RE or NG 4 is insufficient (less than 2 billion pieces / g), a region where the development of the primary coating is insufficient occurs. In this case, even if RA G4 / RE is satisfied, the appearance of the film is deteriorated.
[0108]
[Optional component of annealing separator]
The quenching separator further contains at least one metal compound (referred to as Ca, Sr, Ba compound) selected from the group consisting of Ca, Sr, and Ba, if necessary, and is a annealing separator in% by mass. When the MgO content thereof is 100%, the total content of Ca, Sr, and Ba compounds in terms of sulfate may be 10% or less.
[0109]
When the Ca, Sr, and Ba compounds are contained, the total amount of the Ca, Sr, and Ba compounds is 10% or less in terms of sulfate when the MgO content in the quenching separator is 100% by mass. Here, when one kind of Ca, Sr, Ba compound contained in the annealing separator is defined as MMX, when the MgO content in the annealing separator is 100% by mass, the MMX The content WMX in terms of sulfate can be calculated by the following formula.
W MX = mass% of MX / molecular weight of MX MX ((number of atoms of Ca per M MX molecule) × (CaSO 4 molecular weight) + (number of atoms of Sr per M MX molecule) × (SrSO 4 molecular weight) + (Number of Ba atoms per MMX molecule) x (BaSO 4 molecular weight))
Therefore, the total content of Ca, Sr, Ba compounds in terms of sulfate when the MgO content is 100% by mass in the annealing separator to which one or more Ca, Sr, Ba compounds are added. CMX (hereinafter referred to as oxide-equivalent content CMX of Ca, Sr, and Ba compounds) is the sum of WMX.
[0110]
The Ca, Sr, and Ba compounds lower the reaction temperature between MgO in the annealing separator and SiO 2 on the surface layer of the steel sheet in the finish annealing, and promote the formation of forsterite. If at least one of Ca, Sr, and Ba compounds is contained in a small amount, the above effect can be obtained to some extent. On the other hand, when the sulfate-equivalent content CMX of the Ca, Sr, and Ba compounds exceeds 10%, the reaction between MgO and SiO 2 is rather slowed down, and the formation of forsterite is suppressed. That is, the reactivity is reduced. When the sulfate-equivalent content CMX of the Ca, Sr, and Ba compounds is 10% or less, the formation of forsterite is promoted in the finish annealing.
[0111]
[Manufacturing conditions for finishing annealing process]
The finish annealing process is carried out under the following conditions, for example. A drying process is performed prior to finish annealing. First, the surface of the steel sheet is coated with an annealed separator of an aqueous slurry. A steel sheet coated with an annealing separator on the surface is placed in a furnace kept at 400 to 1000 ° C. and held (drying treatment). As a result, the annealing separator applied to the surface of the steel sheet dries. The holding time is, for example, 10 to 90 seconds.
[0112]
After drying the annealing separator, perform finish annealing. In finish annealing, the annealing temperature is set to 1150 to 1250 ° C., and the base steel sheet (cold-rolled steel sheet) is heated evenly. The soaking time is, for example, 15 to 30 hours. The atmosphere inside the furnace in finish annealing is a well-known atmosphere.
[0113]
In the grain-oriented electrical steel sheet manufactured by the above manufacturing process, a primary film containing Mg 2SiO 4 as a main component is formed. Further, the Al peak position D Al is arranged within the range of 2.0 to 10.0 μm from the surface of the primary coating. Further, the Al oxide number density ND becomes 0.032 to 0.20 / μm 2. Further, the lattice ratio RA Al becomes 5% or less.
[0114]
By the decarburization annealing step and the finish annealing step, each element of the chemical composition of the hot-rolled steel sheet is removed from the components in the steel to some extent. Compositional changes (and processes) in the finish annealing process are sometimes referred to as "purification (annealing)" and are used to control crystal orientation in addition to Sn, Sb, Bi, Te and Pb, especially as inhibitors. Functional S, Al, N, etc. are largely removed. Therefore, the element content in the chemical composition of the base steel sheet of the grain-oriented electrical steel sheet is lower than that of the chemical composition of the hot-rolled steel sheet as described above. If the above-mentioned manufacturing method is carried out using the hot-rolled steel sheet having the above-mentioned chemical composition, a grain-oriented electrical steel sheet having the above-mentioned base material steel sheet having the above-mentioned chemical composition can be manufactured.
[0115]
[Secondary film formation process]
In an example of the method for manufacturing grain-oriented electrical steel sheets according to the present invention, a secondary film forming step may be further carried out after the finish annealing step. In the secondary film forming step, an insulating coating agent mainly composed of colloidal silica and phosphate is applied to the surface of the directional electromagnetic steel plate after the temperature of finish annealing is lowered, and then baking is performed. As a result, a secondary coating, which is a tension insulating coating, is formed on the primary coating.
[0116]
[Magnetic domain subdivision processing process]
The grain-oriented electrical steel sheet according to the present invention may be further subjected to a magnetic domain subdivision treatment step after a finish annealing step or a secondary coating forming step. In the magnetic domain subdivision processing step, the surface of the grain-oriented electrical steel sheet is irradiated with a laser beam having a magnetic domain subdivision effect, or a groove is formed on the surface. In this case, a grain-oriented electrical steel sheet having further excellent magnetic characteristics can be manufactured.
Example
[0117]
Hereinafter, embodiments of the present invention will be specifically described with reference to examples. These examples are examples for confirming the effect of the present invention, and do not limit the present invention.
[0118]

[Manufacturing of grain-oriented electrical steel sheets]
The molten steel having the chemical composition shown in Table 1 was manufactured in a vacuum melting furnace. A slab was manufactured by a continuous casting method using the manufactured molten steel.
[0119]
[table 1]

[0120]
The slab was heated at 1350 ° C. Hot rolling was carried out on the heated slab to produce a hot-rolled steel sheet having a plate thickness of 2.3 mm. The chemical composition of the hot-rolled steel sheet was the same as that of molten steel, as shown in Table 1.
[0121]
The hot-rolled steel sheet was annealed, and then the hot-rolled steel sheet was pickled. The conditions for annealing the hot-rolled steel sheet and the pickling conditions for the hot-rolled steel sheet were the same for all test numbers.
[0122]
The hot-rolled steel sheet after pickling was cold-rolled to produce a cold-rolled steel sheet having a plate thickness of 0.22 mm. In all the test numbers, the cold spread rate was 90.4%.
[0123]
Primary recrystallization annealing was performed on the cold-rolled steel sheet, which also served as decarburization annealing. The annealing temperature in the primary recrystallization annealing was 750 to 950 ° C. in all test numbers, and the holding time at the annealing temperature was 2 minutes.
[0124]
An aqueous slurry was applied to the cold-rolled steel sheet after primary recrystallization annealing, dried, and the annealed separator was applied at a rate of 5 g / m 2 per side. The aqueous slurry was prepared by mixing an annealing separator (raw material powder) with industrial pure water in a mixing ratio of 1: 4. The annealing separator contained MgO, the additives shown in Table 2, and CaSO 4 of 2.0% when the MgO content in the annealing separator was 100% by mass. The content C RE (% by mass) of the Y, La, and Ce compounds in the annealing separator shown in Table 2 is Y in terms of oxide when MgO in the annealing separator is 100% by mass. It means the total content of La and Ce compounds (oxide-equivalent content C RE of Y, La and Ce compounds). Similarly, the Y, La, Ce abundance ratio X RE shown in Table 2 means the ratio of the total number of Y, La, and Ce atoms to the number of Mg atoms contained in the quenching separator. Similarly, the content C G4 (% by mass) of the Ti, Zr, and Hf compounds in the annealing separator shown in Table 2 is Ti in terms of oxide when MgO in the annealing separator is 100% by mass. , Zr, Hf compound total content (Oxide equivalent content C G4 of Ti, Zr, Hf compound). Similarly, the Ti, Zr, Hf abundance ratio X G4 shown in Table 2 means the ratio of the total number of Ti, Zr, Hf atoms to the number of Mg atoms contained in the quenching separator. Similarly, the Y, La, Ce number densities N RE shown in Table 2 are the particle size 0.1 μm of the metal compound selected from the group consisting of Y, La, Ce in the annealing separator before adjusting to the aqueous slurry. It means the number density of the above particles in the raw material powder. Similarly, the Ti, Zr, Hf number density NG4 shown in Table 2 is a metal compound having a particle size of 0.1 μm selected from the group consisting of Ti, Zr, Hf in the quenching separator before preparation into an aqueous slurry. It means the number density of the above particles in the raw material powder.
[0125]
The average particle size PS RE (μm) in Table 2 means the average particle size of the Y, La, and Ce compounds measured by the above-mentioned measuring method. PS G4 in Table 2 means the average particle size of the Ti, Zr, and Hf compounds measured by the above-mentioned measuring method. RA G4 / RE in Table 2 means the average particle size ratio measured by the above-mentioned measuring method.
[0126]
[Table 2]

[0127]
The cold-rolled steel sheet coated with the water-based slurry was placed in a furnace at 900 ° C. for 10 seconds at any test number, dried, and the water-based slurry was dried. After drying, finish annealing treatment was carried out. In the finish annealing treatment, the test numbers were kept at 1200 ° C. for 20 hours. Through the above manufacturing process, a grain-oriented electrical steel sheet having a base steel sheet and a primary coating was manufactured.
[0128]
[Measurement of number density of particles in raw material powder]
The raw material powder was measured with a number-based particle size distribution data using a laser diffraction type particle size distribution measuring device (model: LA950, HORIBA, Ltd.), and the number of particles in 1 g was calculated.
[0129]
[Chemical composition analysis of the base steel sheet of grain-oriented electrical steel sheet]
The chemical composition of the base steel sheet of the manufactured directional electromagnetic steel sheets of test numbers 1 to 63 was determined by the spark discharge emission analysis method and the atomic absorption spectroscopy. The obtained chemical composition is shown in Table 3.
[0130]
[Table 3]

[0131]
[Evaluation test]
[Al peak position D Al measurement test]
For the grain-oriented electrical steel sheet of each test number, the Al peak position D Al was determined by the following measurement method. Specifically, elemental analysis using the GDS method is performed on the surface layer of the grain-oriented electrical steel sheet, and elemental analysis is performed within a range (surface layer) of 100 μm in the depth direction from the surface of the grain-oriented electrical steel sheet. Al contained in each depth position in was identified. The emission intensity of the identified Al was plotted in the depth direction from the surface. The Al peak position D Al was determined based on the plotted Al emission intensity graph. The obtained Al peak position D Al is shown in Table 4.
[0132]
[Table 4]

[0133]
[Al oxide number density ND measurement test]
For the grain-oriented electrical steel sheet of each test number, the Al oxide number density ND (pieces / μm 2) at the Al peak position D Al was determined by the following method. Glow discharge was performed to the Al peak position D Al by the glow discharge emission spectrometer. Al peak position D Of the discharge marks at Al, an arbitrary 36 μm × 50 μm region (observation region) is subjected to elemental analysis using an energy dispersive X-ray spectroscope (EDS), and Al in the observation region is performed. The oxide was identified. Among the precipitates in the observation region, those containing Al and O were identified as Al oxides. The number of specified Al oxides was counted, and the Al oxide number density ND (pieces / μm 2) was obtained by the following formula.
ND = number of specified Al oxides / area of ​​observation area
Table 4 shows the obtained Al oxide number density ND.
[0134]
[Lattice ratio RA Al measurement test]
The lattice ratio RA Al was obtained by the following method. Glow discharge was performed to the Al peak position D Al by the glow discharge emission spectrometer. Al peak position D Of the discharge marks at Al, elemental analysis using an energy dispersive X-ray spectroscope (EDS) is performed on an arbitrary 100 μm × 100 μm region (observation region) without overlap, and observation is performed. Al oxides in the region were identified. Specifically, the region in which the intensity of the characteristic X-ray of O of 50% or more is analyzed with respect to the maximum intensity of the characteristic X-ray of O in the observation region was specified as an oxide. In the specified oxide region, a region in which the intensity of the specific X-ray of Al of 30% or more with respect to the maximum intensity of the specific X-ray of Al is analyzed is specified as Al oxide. Al oxide in the observation area based on the measurement results I made a distribution map of.
[0135]
The created distribution map was divided into 10 μm × 10 μm grids, 100 grids were obtained, and it was specified whether or not Al oxide was contained in each grid. After identification, the number of lattices containing no Al oxide was counted. After obtaining the number of lattices containing no Al oxide, the lattice ratio RA Al (%) was determined by the following formula.
Lattice ratio RA Al = number of lattices not including Al oxide / total number of lattices in the distribution map x 100
[0136]
[Total Y, La, Ce content and Ti, Zr, Hf content in the primary coating]
The Y, La, Ce content (mass%) and Ti, Zr, Hf content (mass%) in the primary coating were measured for the grain-oriented electrical steel sheets of each test number by the following method. Specifically, the grain-oriented electrical steel sheet was electrolyzed to separate the primary coating unit from the surface of the base steel sheet. The Mg in the separated primary film was quantitatively analyzed by ICP-MS. The product of the obtained quantitative value (% by mass) and the molecular weight of Mg 2SiO 4 was divided by the atomic weight of Mg to obtain the content of Mg 2SiO 4 equivalent. The total Y, La, Ce content and the total Ti, Zr, Hf content in the primary coating were measured by the following method. The primary film was separated from the surface of the base steel sheet by electrolyzing the grain-oriented electrical steel sheet. The total content of Y, La and Ce (mass%) and the total content of Ti, Zr and Hf (% by mass) in the separated primary film were quantitatively analyzed by ICP-MS. Table 4 shows the total Y, La, and Ce contents and the total Ti, Zr, and Hf contents obtained by the measurement.
[0137]
[Magnetic characterization test]
The magnetic properties of the grain-oriented electrical steel sheets of each test number were evaluated by the following method. Specifically, a sample having a length of 300 mm and a width of 60 mm in the rolling direction was taken from the grain-oriented electrical steel sheet of each test number. A magnetic field of 800 A / m was applied to the sample to determine the magnetic flux density B8. Table 4 shows the test results.
[0138]
[Adhesion evaluation test]
The adhesion of the primary coating of grain-oriented electrical steel sheets of each test number was evaluated by the following method. Specifically, a sample having a length of 60 mm and a width of 15 mm in the rolling direction was taken from the grain-oriented electrical steel sheet of each test number. A bending test was performed on the sample with a curvature of 10 mm. The bending test was carried out by using a bending resistance tester (manufactured by TP Giken Co., Ltd.) and installing it on the sample so that the axial direction of the cylinder coincided with the width direction of the sample. The surface of the sample after the bending test was observed, and the total area of ​​the area where the primary coating remained without peeling was determined. The residual ratio of the primary coating was determined by the following formula.
Primary film residual rate = total area of ​​area where the primary film remains without peeling / sample surface area x 100
[0139]
[Film appearance evaluation test]
The appearance of the primary coating of grain-oriented electrical steel sheets of each test number was evaluated by the following method. Samples having a length of 15 mm and a width of 60 mm in the rolling direction were taken from the grain-oriented electrical steel sheets of each test number. The appearance of the sample was visually observed, and when the color was uniformly achromatic in the width direction and unevenness in color and lightness was not visually recognized, it was judged that the appearance of the film was good. If the area where the color unevenness occurs is less than 5%, it is evaluated as “◯”, if it is 5% or more and less than 10%, it is evaluated as “Δ”, and if it is 10% or more, it is evaluated as “×”.
[0140]
[Test results]
Table 4 shows the test results. With reference to Table 4, in test numbers 11, 15, 16, 20, 23, 24, 31-35, 38-40, 44, 45 and 49, the chemical composition is appropriate and in the quenching separator. Conditions (Oxide-equivalent content of Y, La, Ce compounds C RE, Ti, Zr, Hf Oxide-equivalent content of compounds C G4, total content C RE + C G4, Y, La, Ce Average particle size of compounds PS RE, average particle size ratio AR G4 / RE, atomic number ratio X RE / X G4) were appropriate. As a result, the Al peak position D Al was in the range of 2.0 to 10.0 μm, and the number density ND of Al oxides was in the range of 0.032 to 0.20 / μm 2. Further, the lattice ratio RA Al of the Al oxide was 5% or less. The Y, La, and Ce contents in the primary coating were in the range of 0.001 to 6.0%, and the Ti, Zr, and Hf contents were in the range of 0.0005 to 4.0%. .. As a result, in the grain-oriented electrical steel sheets having these test numbers, the magnetic flux density B8 was 1.92T or more, and excellent magnetic characteristics were obtained. Furthermore, the residual ratio of the primary film was 90% or more, showing excellent adhesion. Furthermore, the appearance of the primary coating was also good.
[0141]
Further, in particular, test numbers 21, 24, and 35 contain at least two kinds of metal compounds selected from the group consisting of Ti, Zr, and Hf, and the primary coating exhibits extremely excellent adhesion and adhesion. It showed extremely excellent magnetic properties.
[0142]
On the other hand, in Test Nos. 1 to 7, 9, 10, 13, 14 and 18, although the chemical composition of the steel sheet was appropriate, the oxide-equivalent content C RE of the Y, La and Ce compounds in the annealing separator was found. It was too low. Therefore, the Al peak position D Al of these test numbers was less than 2.0 μm. As a result, in these test numbers, the residual ratio of the primary coating was less than 90%, and the adhesion was low. In addition, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0143]
In test numbers 8, 12, 17, 22 and 28, the chemical composition of the steel sheet was appropriate, but the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds was too low. Therefore, in these test numbers, the number density ND of Al oxides was less than 0.032 / μm 2, and the Al peak position D Al was less than 2.0 μm. As a result, in these test numbers, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0144]
In test numbers 37, 42, 47, 51 and 53, the average particle size ratio RA G4 / RE was too large. Therefore, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0145]
In test number 19, the Ti, Zr, and Hf oxide equivalent contents C G4 were too high. Therefore, the magnetic flux density B8 was less than 1.92T, and the magnetic characteristics were low. In addition, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0146]
In test number 21, the atomic number ratio X RE / X G4 was too high. Therefore, the Al peak position D Al exceeded 10.0. As a result, in this test number, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0147]
In test numbers 25 and 26, the oxide-equivalent content C RE of the Y, La, and Ce compounds was too high. Therefore, the Al peak position D Al exceeded 10.0 μm. As a result, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0148]
In test number 27, the oxide-equivalent content C G4 of the Ti, Zr, and Hf compounds was too high. Therefore, the number density ND of Al oxide exceeded 0.2 / μm 2. As a result, the magnetic properties were low.
[0149]
In test number 29, the atomic number ratio X RE / X G4 was too low. Al peak position D Al was less than 2.0. As a result, the residual ratio of the primary film was less than 90%, and the adhesion was low.
[0150]
In test number 30, the total content C RE + C G4 was too low. As a result, the Al peak position D Al was less than 2.0, and the number density ND of Al oxides was less than 0.032 / μm 2. As a result, the residual ratio of the primary film was less than 90%, and the adhesion was low. In addition, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0151]
In test numbers 41 and 46, the average particle size PS RE of the Y, La, and Ce compounds was too large. Therefore, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0152]
In test numbers 36, 43, and 48, the average particle size ratio RA G4 / RE was too small. Therefore, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0153]
In test number 50, the average particle size ratio RA G4 / RE was too small, and the average particle size PS RE was too large. Therefore, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0154]
In test numbers 52, 54 and 55, the average particle size PS RE of the Y, La and Ce compounds was too large. Furthermore, the average particle size ratio RA G4 / RE was too small. Therefore, the lattice ratio RA Al exceeded 5%, and the appearance of the primary coating was deteriorated.
[0155]
In test numbers 56 to 59, the number density of particles in the annealed separator raw material powder of the Y, La, and Ce compounds was too low. Therefore, the Al peak position D Al was too low, and the Al oxide number density ND was too small. As a result, the adhesion of the primary coating was low.
[0156]
In test numbers 60 to 63, the number density of particles in the annealed separator raw material powder of the Ti, Zr, and Hf compounds was too low. Therefore, the Al oxide number density ND was too small. As a result, the adhesion of the primary coating was low.
[0157]

[Manufacturing of grain-oriented electrical steel sheets]
In the same manner as in Example 1, an aqueous slurry was applied to and dried the cold-rolled steel sheet after primary recrystallization annealing of test numbers 64 to 79 produced from molten steel having the chemical composition shown in Table 1, and an annealed separator was applied. Was applied at a rate of 5 g / m 2 per side. The aqueous slurry was prepared by mixing an annealing separator and industrial pure water in a mixing ratio of 1: 6. The annealing separators were MgO, the additives shown in Table 5, 2.5% CeO 2 and 2.0% ZrO 2, 4.0% when the MgO content was 100% by mass. It contained TiO 2. The Y, La, Ce content C RE in the annealing separator shown in Table 5 is an oxide conversion of the Y, La, Ce compound when the MgO content in the annealing separator is 100% by mass. Means the total content of. Similarly, the Y, La, Ce abundance ratio X RE shown in Table 5 means the ratio of the total number of Y, La, and Ce atoms to the number of Mg atoms contained in the quenching separator. Similarly, the Ti, Zr, Hf content C G4 in the annealing separator shown in Table 5 is an oxide of the Ti, Zr, Hf compound when the MgO content in the annealing separator is 100% by mass. Means the converted total content. Similarly, the Ti, Zr, Hf abundance ratio X G4 shown in Table 5 means the ratio of the total number of Ti, Zr, Hf atoms to the number of Mg atoms contained in the quenching separator. Similarly, the Ca, Sr, and Ba contents CMX shown in Table 5 are the total sulfate equivalents of the Ca, Sr, and Ba compounds when the MgO content in the annealing separator is 100% by mass. It means the content. Similarly, PS RE shown in Table 5 means the average particle size of all the Y, La, and Ce compounds contained in the annealing separator. Similarly, PS G4 shown in Table 5 means the average particle size of all Ti, Zr, and Hf compounds contained in the annealing separator. Similarly, RA RE / G4 shown in Table 5 means the ratio of PS G4 to the PS RE.
[0158]
[Table 5]

[0159]
The cold-rolled steel sheet coated with the water-based slurry was placed in a furnace at 900 ° C. for 10 seconds at any test number to dry the water-based slurry. After drying, finish annealing treatment was carried out. In the finish annealing treatment, the test numbers were kept at 1200 ° C. for 20 hours. Through the above manufacturing process, a grain-oriented electrical steel sheet having a base steel sheet and a primary coating was manufactured.
[0160]
[Chemical composition analysis of the base steel sheet of grain-oriented electrical steel sheet]
The chemical composition of the base steel sheet of the manufactured directional electromagnetic steel sheets of test numbers 64 to 79 was determined by the spark discharge emission analysis method and the atomic absorption spectroscopy. The obtained chemical composition is shown in Table 6.
[0161]
[Table 6]

[0162]
[Evaluation test of coating]
For the directional electromagnetic steel plate of each test number, the Al oxide number density ND (pieces / μm 2) at the Al peak position D Al and the Al peak position D Al, in the primary coating, in the same manner as in Example 1. The Y, La, Ce content, Ti, Zr, Hf content and lattice ratio RA Al were determined. Table 7 shows the DA, Al oxide number density ND, Y, La, Ce content, Ti, Zr, Hf content, and RA Al in the primary coating obtained by measurement.

The scope of the claims
[Claim 1]
It is a grain-oriented electrical steel sheet
By mass%,
C: 0.005% or less,
Si: 2.5-4.5%,
Mn: 0.02-0.2%,
One or more elements selected from the group consisting of S and Se: 0.005% or less in total,
Sol. Al: 0.01% or less, and
N: 0.01% or less
A base steel sheet containing a chemical composition containing Fe and impurities, and the balance
It is formed on the surface of the base steel sheet and has a primary coating containing Mg 2SiO 4 as a main component.
The peak position of the Al emission intensity obtained when elemental analysis by the glow discharge emission spectrometry is performed from the surface of the primary coating in the plate thickness direction of the directional electromagnetic steel plate is in the plate thickness direction from the surface of the primary coating. Arranged within the range of 2.0 to 10.0 μm,
It is an Al oxide at the peak position of the Al emission intensity, and the number density of the Al oxides having a diameter equivalent to a circle based on an area of ​​0.2 μm or more is 0.032 to 0.20 / μm 2. ,
In the distribution map of the Al oxide of 100 μm × 100 μm at the peak position of the Al emission intensity obtained by the glow discharge emission analysis method, the distribution map is divided by a grid of 10 μm × 10 μm. A directional electromagnetic steel plate in which the ratio of the number of lattices not containing Al oxide to the total number of lattices is 5% or less.
[Claim 2]
By mass%,
C: 0.1% or less,
Si: 2.5-4.5%,
Mn: 0.02-0.2%,
One or more elements selected from the group consisting of S and Se: 0.005 to 0.07% in total,
Sol. Al: 0.005 to 0.05% and
N: 0.001 to 0.030%
A process of manufacturing a cold-rolled steel sheet by cold-rolling a hot-rolled steel sheet containing Fe and impurities at a cold-rolling rate of 80% or more.
The process of decarburizing and annealing the cold-rolled steel sheet and
A step of applying an aqueous slurry containing an annealing separator to the surface of the cold-rolled steel sheet after decarburization and annealing, and drying the aqueous slurry on the surface of the cold-rolled steel sheet in a furnace at 400 to 1000 ° C.
It is provided with a step of performing finish annealing on the cold-rolled steel sheet after the aqueous slurry has been dried.
The annealing separator is
With MgO
At least one metal compound selected from the group consisting of Y, La, and Ce,
Containing at least one metal compound selected from the group consisting of Ti, Zr, and Hf,
When the MgO content in the annealing separator is 100% by mass, the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide is 0.5 to 6. It is 0.0%, and the total content of the metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide is 0.8 to 10.0%.
The average particle size of the metal compound selected from the group consisting of Y, La, and Ce is 10 μm or less.
The ratio of the average particle size of the metal compound selected from the group consisting of Ti, Zr and Hf to the average particle size of the metal compound selected from the group consisting of Y, La and Ce is 0.1 to 3. 0,
The total content of the metal compound selected from the group consisting of Y, La and Ce in terms of oxide and the total content of the compound of the metal selected from the group consisting of Ti, Zr and Hf in terms of oxide. The total with the amount is 2.0 to 12.5%,
The ratio of the total number of Ti, Zr, and Hf atoms contained in the quenching separator to the total number of Y, La, and Ce atoms is 0.15 to 3.6.
Furthermore, it is a particle of a metal compound selected from the group consisting of Y, La, and Ce, and has a volume-based sphere-equivalent diameter, and the number density of particles of 0.1 μm or more is 2 billion / g or more. can be,
Furthermore, it is a particle of a metal compound selected from the group consisting of Ti, Zr, and Hf, and has a volume-based sphere-equivalent diameter, and the number density of particles of 0.1 μm or more is 2 billion / g or more. There is a method for manufacturing directional electromagnetic steel sheets.
[Claim 3]
The method for manufacturing grain-oriented electrical steel sheets according to claim 2.
The annealing separator further contains at least one metal compound selected from the group consisting of Ca, Sr, and Ba.
When the MgO content in the annealing separator is 100% by mass, the total content of the metal compound selected from the group consisting of Ca, Sr, and Ba in terms of sulfate is 10% or less. Manufacturing method of grain-oriented electrical steel sheet.
[Claim 4]
The method for manufacturing grain-oriented electrical steel sheets according to claim 2 or 3.
The chemical composition of the hot-rolled steel sheet is further replaced with a part of Fe.
A method for manufacturing grain-oriented electrical steel sheets, which contains 0.6% or less in total of one or more elements selected from the group consisting of Cu, Sb and Sn.
[Claim 5]
The method for manufacturing grain-oriented electrical steel sheets according to any one of claims 2 to 4.
The chemical composition of the hot-rolled steel sheet is further replaced with a part of Fe.
A method for manufacturing grain-oriented electrical steel sheets, which contains 0.03% or less in total of one or more elements selected from the group consisting of Bi, Te and Pb.
[Claim 6]
Annealing separator used in the manufacture of grain-oriented electrical steel sheets
With MgO
At least one metal compound selected from the group consisting of Y, La, and Ce,
Containing at least one metal compound selected from the group consisting of Ti, Zr, and Hf,
When the MgO content in the annealing separator is 100% by mass, the total content of the metal compound selected from the group consisting of Y, La, and Ce in terms of oxide is 0.5 to 6. It is 0.0%, and the total content of the metal compound selected from the group consisting of Ti, Zr, and Hf in terms of oxide is 0.8 to 10.0%.
The average particle size of the metal compound selected from the group consisting of Y, La, and Ce is 10 μm or less.
The ratio of the average particle size of the metal compound selected from the group consisting of Ti, Zr and Hf to the average particle size of the metal compound selected from the group consisting of Y, La and Ce is 0.1 to 3. 0,
The total content of the metal compound selected from the group consisting of Y, La and Ce in terms of oxide and the total content of the compound of the metal selected from the group consisting of Ti, Zr and Hf in terms of oxide. The total with the amount is 2.0 to 12.5%,
The ratio of the total number of Ti, Zr, and Hf atoms contained in the quenching separator to the total number of Y, La, and Ce atoms is 0.15 to 3.6.
Furthermore, it is a particle of a metal compound selected from the group consisting of Y, La, and Ce, and has a volume-based sphere-equivalent diameter, and the number density of particles of 0.1 μm or more is 2 billion / g or more. can be,
Furthermore, it is a particle of a metal compound selected from the group consisting of Ti, Zr, and Hf, and has a volume-based sphere-equivalent diameter, and the number density of particles of 0.1 μm or more is 2 billion / g or more. There is a quenching separator.
[Claim 7]
The annealing separator according to claim 6, further containing at least one metal compound selected from the group consisting of Ca, Sr, and Ba.
When the MgO content in the annealing separator is 100% by mass, the total content of the metal compound selected from the group consisting of Ca, Sr, and Ba in terms of sulfate is 10% or less. Annealing separator.